contrib/bind/lib/dns/resolver.c

   1 /*
   2  * Copyright (C) 2004-2009  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: resolver.c,v 1.355.12.44.2.2 2010/01/07 17:19:22 each Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/platform.h>
  25 #include <isc/print.h>
  26 #include <isc/string.h>
  27 #include <isc/random.h>
  28 #include <isc/task.h>
  29 #include <isc/stats.h>
  30 #include <isc/timer.h>
  31 #include <isc/util.h>
  32
  33 #include <dns/acl.h>
  34 #include <dns/adb.h>
  35 #include <dns/cache.h>
  36 #include <dns/db.h>
  37 #include <dns/dispatch.h>
  38 #include <dns/ds.h>
  39 #include <dns/events.h>
  40 #include <dns/forward.h>
  41 #include <dns/keytable.h>
  42 #include <dns/log.h>
  43 #include <dns/message.h>
  44 #include <dns/ncache.h>
  45 #include <dns/opcode.h>
  46 #include <dns/peer.h>
  47 #include <dns/rbt.h>
  48 #include <dns/rcode.h>
  49 #include <dns/rdata.h>
  50 #include <dns/rdataclass.h>
  51 #include <dns/rdatalist.h>
  52 #include <dns/rdataset.h>
  53 #include <dns/rdatastruct.h>
  54 #include <dns/rdatatype.h>
  55 #include <dns/resolver.h>
  56 #include <dns/result.h>
  57 #include <dns/rootns.h>
  58 #include <dns/stats.h>
  59 #include <dns/tsig.h>
  60 #include <dns/validator.h>
  61
  62 #define DNS_RESOLVER_TRACE
  63 #ifdef DNS_RESOLVER_TRACE
  64 #define RTRACE(m)       isc_log_write(dns_lctx, \
  65                                       DNS_LOGCATEGORY_RESOLVER, \
  66                                       DNS_LOGMODULE_RESOLVER, \
  67                                       ISC_LOG_DEBUG(3), \
  68                                       "res %p: %s", res, (m))
  69 #define RRTRACE(r, m)   isc_log_write(dns_lctx, \
  70                                       DNS_LOGCATEGORY_RESOLVER, \
  71                                       DNS_LOGMODULE_RESOLVER, \
  72                                       ISC_LOG_DEBUG(3), \
  73                                       "res %p: %s", (r), (m))
  74 #define FCTXTRACE(m)    isc_log_write(dns_lctx, \
  75                                       DNS_LOGCATEGORY_RESOLVER, \
  76                                       DNS_LOGMODULE_RESOLVER, \
  77                                       ISC_LOG_DEBUG(3), \
  78                                       "fctx %p(%s'): %s", fctx, fctx->info, (m))
  79 #define FCTXTRACE2(m1, m2) \
  80                         isc_log_write(dns_lctx, \
  81                                       DNS_LOGCATEGORY_RESOLVER, \
  82                                       DNS_LOGMODULE_RESOLVER, \
  83                                       ISC_LOG_DEBUG(3), \
  84                                       "fctx %p(%s): %s %s", \
  85                                       fctx, fctx->info, (m1), (m2))
  86 #define FTRACE(m)       isc_log_write(dns_lctx, \
  87                                       DNS_LOGCATEGORY_RESOLVER, \
  88                                       DNS_LOGMODULE_RESOLVER, \
  89                                       ISC_LOG_DEBUG(3), \
  90                                       "fetch %p (fctx %p(%s)): %s", \
  91                                       fetch, fetch->private, \
  92                                       fetch->private->info, (m))
  93 #define QTRACE(m)       isc_log_write(dns_lctx, \
  94                                       DNS_LOGCATEGORY_RESOLVER, \
  95                                       DNS_LOGMODULE_RESOLVER, \
  96                                       ISC_LOG_DEBUG(3), \
  97                                       "resquery %p (fctx %p(%s)): %s", \
  98                                       query, query->fctx, \
  99                                       query->fctx->info, (m))
 100 #else
 101 #define RTRACE(m)
 102 #define RRTRACE(r, m)
 103 #define FCTXTRACE(m)
 104 #define FTRACE(m)
 105 #define QTRACE(m)
 106 #endif
 107
 108 /*%
 109  * Maximum EDNS0 input packet size.
 110  */
 111 #define RECV_BUFFER_SIZE                4096            /* XXXRTH  Constant. */
 112
 113 /*%
 114  * This defines the maximum number of timeouts we will permit before we
 115  * disable EDNS0 on the query.
 116  */
 117 #define MAX_EDNS0_TIMEOUTS      3
 118
 119 typedef struct fetchctx fetchctx_t;
 120
 121 typedef struct query {
 122         /* Locked by task event serialization. */
 123         unsigned int                    magic;
 124         fetchctx_t *                    fctx;
 125         isc_mem_t *                     mctx;
 126         dns_dispatchmgr_t *             dispatchmgr;
 127         dns_dispatch_t *                dispatch;
 128         isc_boolean_t                   exclusivesocket;
 129         dns_adbaddrinfo_t *             addrinfo;
 130         isc_socket_t *                  tcpsocket;
 131         isc_time_t                      start;
 132         dns_messageid_t                 id;
 133         dns_dispentry_t *               dispentry;
 134         ISC_LINK(struct query)          link;
 135         isc_buffer_t                    buffer;
 136         isc_buffer_t                    *tsig;
 137         dns_tsigkey_t                   *tsigkey;
 138         unsigned int                    options;
 139         unsigned int                    attributes;
 140         unsigned int                    sends;
 141         unsigned int                    connects;
 142         unsigned char                   data[512];
 143 } resquery_t;
 144
 145 #define QUERY_MAGIC                     ISC_MAGIC('Q', '!', '!', '!')
 146 #define VALID_QUERY(query)              ISC_MAGIC_VALID(query, QUERY_MAGIC)
 147
 148 #define RESQUERY_ATTR_CANCELED          0x02
 149
 150 #define RESQUERY_CONNECTING(q)          ((q)->connects > 0)
 151 #define RESQUERY_CANCELED(q)            (((q)->attributes & \
 152                                           RESQUERY_ATTR_CANCELED) != 0)
 153 #define RESQUERY_SENDING(q)             ((q)->sends > 0)
 154
 155 typedef enum {
 156         fetchstate_init = 0,            /*%< Start event has not run yet. */
 157         fetchstate_active,
 158         fetchstate_done                 /*%< FETCHDONE events posted. */
 159 } fetchstate;
 160
 161 typedef enum {
 162         badns_unreachable = 0,
 163         badns_response,
 164         badns_validation
 165 } badnstype_t;
 166
 167 struct fetchctx {
 168         /*% Not locked. */
 169         unsigned int                    magic;
 170         dns_resolver_t *                res;
 171         dns_name_t                      name;
 172         dns_rdatatype_t                 type;
 173         unsigned int                    options;
 174         unsigned int                    bucketnum;
 175         char *                  info;
 176         /*% Locked by appropriate bucket lock. */
 177         fetchstate                      state;
 178         isc_boolean_t                   want_shutdown;
 179         isc_boolean_t                   cloned;
 180         isc_boolean_t                   spilled;
 181         unsigned int                    references;
 182         isc_event_t                     control_event;
 183         ISC_LINK(struct fetchctx)       link;
 184         ISC_LIST(dns_fetchevent_t)      events;
 185         /*% Locked by task event serialization. */
 186         dns_name_t                      domain;
 187         dns_rdataset_t                  nameservers;
 188         unsigned int                    attributes;
 189         isc_timer_t *                   timer;
 190         isc_time_t                      expires;
 191         isc_interval_t                  interval;
 192         dns_message_t *                 qmessage;
 193         dns_message_t *                 rmessage;
 194         ISC_LIST(resquery_t)            queries;
 195         dns_adbfindlist_t               finds;
 196         dns_adbfind_t *                 find;
 197         dns_adbfindlist_t               altfinds;
 198         dns_adbfind_t *                 altfind;
 199         dns_adbaddrinfolist_t           forwaddrs;
 200         dns_adbaddrinfolist_t           altaddrs;
 201         isc_sockaddrlist_t              forwarders;
 202         dns_fwdpolicy_t                 fwdpolicy;
 203         isc_sockaddrlist_t              bad;
 204         isc_sockaddrlist_t              edns;
 205         isc_sockaddrlist_t              edns512;
 206         dns_validator_t                 *validator;
 207         ISC_LIST(dns_validator_t)       validators;
 208         dns_db_t *                      cache;
 209         dns_adb_t *                     adb;
 210
 211         /*%
 212          * The number of events we're waiting for.
 213          */
 214         unsigned int                    pending;
 215
 216         /*%
 217          * The number of times we've "restarted" the current
 218          * nameserver set.  This acts as a failsafe to prevent
 219          * us from pounding constantly on a particular set of
 220          * servers that, for whatever reason, are not giving
 221          * us useful responses, but are responding in such a
 222          * way that they are not marked "bad".
 223          */
 224         unsigned int                    restarts;
 225
 226         /*%
 227          * The number of timeouts that have occurred since we
 228          * last successfully received a response packet.  This
 229          * is used for EDNS0 black hole detection.
 230          */
 231         unsigned int                    timeouts;
 232
 233         /*%
 234          * Look aside state for DS lookups.
 235          */
 236         dns_name_t                      nsname;
 237         dns_fetch_t *                   nsfetch;
 238         dns_rdataset_t                  nsrrset;
 239
 240         /*%
 241          * Number of queries that reference this context.
 242          */
 243         unsigned int                    nqueries;
 244
 245         /*%
 246          * The reason to print when logging a successful
 247          * response to a query.
 248          */
 249         const char *                    reason;
 250
 251         /*%
 252          * Fetch-local statistics for detailed logging.
 253          */
 254         isc_result_t                    result; /*%< fetch result  */
 255         isc_result_t                    vresult; /*%< validation result  */
 256         int                             exitline;
 257         isc_time_t                      start;
 258         isc_uint64_t                    duration;
 259         isc_boolean_t                   logged;
 260         unsigned int                    querysent;
 261         unsigned int                    referrals;
 262         unsigned int                    lamecount;
 263         unsigned int                    neterr;
 264         unsigned int                    badresp;
 265         unsigned int                    adberr;
 266         unsigned int                    findfail;
 267         unsigned int                    valfail;
 268         isc_boolean_t                   timeout;
 269 };
 270
 271 #define FCTX_MAGIC                      ISC_MAGIC('F', '!', '!', '!')
 272 #define VALID_FCTX(fctx)                ISC_MAGIC_VALID(fctx, FCTX_MAGIC)
 273
 274 #define FCTX_ATTR_HAVEANSWER            0x0001
 275 #define FCTX_ATTR_GLUING                0x0002
 276 #define FCTX_ATTR_ADDRWAIT              0x0004
 277 #define FCTX_ATTR_SHUTTINGDOWN          0x0008
 278 #define FCTX_ATTR_WANTCACHE             0x0010
 279 #define FCTX_ATTR_WANTNCACHE            0x0020
 280 #define FCTX_ATTR_NEEDEDNS0             0x0040
 281 #define FCTX_ATTR_TRIEDFIND             0x0080
 282 #define FCTX_ATTR_TRIEDALT              0x0100
 283
 284 #define HAVE_ANSWER(f)          (((f)->attributes & FCTX_ATTR_HAVEANSWER) != \
 285                                  0)
 286 #define GLUING(f)               (((f)->attributes & FCTX_ATTR_GLUING) != \
 287                                  0)
 288 #define ADDRWAIT(f)             (((f)->attributes & FCTX_ATTR_ADDRWAIT) != \
 289                                  0)
 290 #define SHUTTINGDOWN(f)         (((f)->attributes & FCTX_ATTR_SHUTTINGDOWN) \
 291                                  != 0)
 292 #define WANTCACHE(f)            (((f)->attributes & FCTX_ATTR_WANTCACHE) != 0)
 293 #define WANTNCACHE(f)           (((f)->attributes & FCTX_ATTR_WANTNCACHE) != 0)
 294 #define NEEDEDNS0(f)            (((f)->attributes & FCTX_ATTR_NEEDEDNS0) != 0)
 295 #define TRIEDFIND(f)            (((f)->attributes & FCTX_ATTR_TRIEDFIND) != 0)
 296 #define TRIEDALT(f)             (((f)->attributes & FCTX_ATTR_TRIEDALT) != 0)
 297
 298 typedef struct {
 299         dns_adbaddrinfo_t *             addrinfo;
 300         fetchctx_t *                    fctx;
 301 } dns_valarg_t;
 302
 303 struct dns_fetch {
 304         unsigned int                    magic;
 305         fetchctx_t *                    private;
 306 };
 307
 308 #define DNS_FETCH_MAGIC                 ISC_MAGIC('F', 't', 'c', 'h')
 309 #define DNS_FETCH_VALID(fetch)          ISC_MAGIC_VALID(fetch, DNS_FETCH_MAGIC)
 310
 311 typedef struct fctxbucket {
 312         isc_task_t *                    task;
 313         isc_mutex_t                     lock;
 314         ISC_LIST(fetchctx_t)            fctxs;
 315         isc_boolean_t                   exiting;
 316         isc_mem_t *                     mctx;
 317 } fctxbucket_t;
 318
 319 typedef struct alternate {
 320         isc_boolean_t                   isaddress;
 321         union   {
 322                 isc_sockaddr_t          addr;
 323                 struct {
 324                         dns_name_t      name;
 325                         in_port_t       port;
 326                 } _n;
 327         } _u;
 328         ISC_LINK(struct alternate)      link;
 329 } alternate_t;
 330
 331 struct dns_resolver {
 332         /* Unlocked. */
 333         unsigned int                    magic;
 334         isc_mem_t *                     mctx;
 335         isc_mutex_t                     lock;
 336         isc_mutex_t                     nlock;
 337         isc_mutex_t                     primelock;
 338         dns_rdataclass_t                rdclass;
 339         isc_socketmgr_t *               socketmgr;
 340         isc_timermgr_t *                timermgr;
 341         isc_taskmgr_t *                 taskmgr;
 342         dns_view_t *                    view;
 343         isc_boolean_t                   frozen;
 344         unsigned int                    options;
 345         dns_dispatchmgr_t *             dispatchmgr;
 346         dns_dispatch_t *                dispatchv4;
 347         isc_boolean_t                   exclusivev4;
 348         dns_dispatch_t *                dispatchv6;
 349         isc_boolean_t                   exclusivev6;
 350         unsigned int                    ndisps;
 351         unsigned int                    nbuckets;
 352         fctxbucket_t *                  buckets;
 353         isc_uint32_t                    lame_ttl;
 354         ISC_LIST(alternate_t)           alternates;
 355         isc_uint16_t                    udpsize;
 356 #if USE_ALGLOCK
 357         isc_rwlock_t                    alglock;
 358 #endif
 359         dns_rbt_t *                     algorithms;
 360 #if USE_MBSLOCK
 361         isc_rwlock_t                    mbslock;
 362 #endif
 363         dns_rbt_t *                     mustbesecure;
 364         unsigned int                    spillatmax;
 365         unsigned int                    spillatmin;
 366         isc_timer_t *                   spillattimer;
 367         isc_boolean_t                   zero_no_soa_ttl;
 368
 369         /* Locked by lock. */
 370         unsigned int                    references;
 371         isc_boolean_t                   exiting;
 372         isc_eventlist_t                 whenshutdown;
 373         unsigned int                    activebuckets;
 374         isc_boolean_t                   priming;
 375         unsigned int                    spillat;        /* clients-per-query */
 376         unsigned int                    nextdisp;
 377         /* Locked by primelock. */
 378         dns_fetch_t *                   primefetch;
 379         /* Locked by nlock. */
 380         unsigned int                    nfctx;
 381 };
 382
 383 #define RES_MAGIC                       ISC_MAGIC('R', 'e', 's', '!')
 384 #define VALID_RESOLVER(res)             ISC_MAGIC_VALID(res, RES_MAGIC)
 385
 386 /*%
 387  * Private addrinfo flags.  These must not conflict with DNS_FETCHOPT_NOEDNS0,
 388  * which we also use as an addrinfo flag.
 389  */
 390 #define FCTX_ADDRINFO_MARK              0x0001
 391 #define FCTX_ADDRINFO_FORWARDER         0x1000
 392 #define UNMARKED(a)                     (((a)->flags & FCTX_ADDRINFO_MARK) \
 393                                          == 0)
 394 #define ISFORWARDER(a)                  (((a)->flags & \
 395                                          FCTX_ADDRINFO_FORWARDER) != 0)
 396
 397 #define NXDOMAIN(r) (((r)->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0)
 398
 399 static void destroy(dns_resolver_t *res);
 400 static void empty_bucket(dns_resolver_t *res);
 401 static isc_result_t resquery_send(resquery_t *query);
 402 static void resquery_response(isc_task_t *task, isc_event_t *event);
 403 static void resquery_connected(isc_task_t *task, isc_event_t *event);
 404 static void fctx_try(fetchctx_t *fctx, isc_boolean_t retrying);
 405 static isc_boolean_t fctx_destroy(fetchctx_t *fctx);
 406 static isc_result_t ncache_adderesult(dns_message_t *message,
 407                                       dns_db_t *cache, dns_dbnode_t *node,
 408                                       dns_rdatatype_t covers,
 409                                       isc_stdtime_t now, dns_ttl_t maxttl,
 410                                       dns_rdataset_t *ardataset,
 411                                       isc_result_t *eresultp);
 412 static void validated(isc_task_t *task, isc_event_t *event);
 413 static void maybe_destroy(fetchctx_t *fctx);
 414 static void add_bad(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
 415                     isc_result_t reason, badnstype_t badtype);
 416
 417 /*%
 418  * Increment resolver-related statistics counters.
 419  */
 420 static inline void
 421 inc_stats(dns_resolver_t *res, isc_statscounter_t counter) {
 422         if (res->view->resstats != NULL)
 423                 isc_stats_increment(res->view->resstats, counter);
 424 }
 425
 426 static isc_result_t
 427 valcreate(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, dns_name_t *name,
 428           dns_rdatatype_t type, dns_rdataset_t *rdataset,
 429           dns_rdataset_t *sigrdataset, unsigned int valoptions,
 430           isc_task_t *task)
 431 {
 432         dns_validator_t *validator = NULL;
 433         dns_valarg_t *valarg;
 434         isc_result_t result;
 435
 436         valarg = isc_mem_get(fctx->res->buckets[fctx->bucketnum].mctx,
 437                              sizeof(*valarg));
 438         if (valarg == NULL)
 439                 return (ISC_R_NOMEMORY);
 440
 441         valarg->fctx = fctx;
 442         valarg->addrinfo = addrinfo;
 443
 444         if (!ISC_LIST_EMPTY(fctx->validators))
 445                 INSIST((valoptions & DNS_VALIDATOR_DEFER) != 0);
 446
 447         result = dns_validator_create(fctx->res->view, name, type, rdataset,
 448                                       sigrdataset, fctx->rmessage,
 449                                       valoptions, task, validated, valarg,
 450                                       &validator);
 451         if (result == ISC_R_SUCCESS) {
 452                 inc_stats(fctx->res, dns_resstatscounter_val);
 453                 if ((valoptions & DNS_VALIDATOR_DEFER) == 0) {
 454                         INSIST(fctx->validator == NULL);
 455                         fctx->validator  = validator;
 456                 }
 457                 ISC_LIST_APPEND(fctx->validators, validator, link);
 458         } else
 459                 isc_mem_put(fctx->res->buckets[fctx->bucketnum].mctx,
 460                             valarg, sizeof(*valarg));
 461         return (result);
 462 }
 463
 464 static isc_boolean_t
 465 rrsig_fromchildzone(fetchctx_t *fctx, dns_rdataset_t *rdataset) {
 466         dns_namereln_t namereln;
 467         dns_rdata_rrsig_t rrsig;
 468         dns_rdata_t rdata = DNS_RDATA_INIT;
 469         int order;
 470         isc_result_t result;
 471         unsigned int labels;
 472
 473         for (result = dns_rdataset_first(rdataset);
 474              result == ISC_R_SUCCESS;
 475              result = dns_rdataset_next(rdataset)) {
 476                 dns_rdataset_current(rdataset, &rdata);
 477                 result = dns_rdata_tostruct(&rdata, &rrsig, NULL);
 478                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
 479                 namereln = dns_name_fullcompare(&rrsig.signer, &fctx->domain,
 480                                                 &order, &labels);
 481                 if (namereln == dns_namereln_subdomain)
 482                         return (ISC_TRUE);
 483                 dns_rdata_reset(&rdata);
 484         }
 485         return (ISC_FALSE);
 486 }
 487
 488 static isc_boolean_t
 489 fix_mustbedelegationornxdomain(dns_message_t *message, fetchctx_t *fctx) {
 490         dns_name_t *name;
 491         dns_name_t *domain = &fctx->domain;
 492         dns_rdataset_t *rdataset;
 493         dns_rdatatype_t type;
 494         isc_result_t result;
 495         isc_boolean_t keep_auth = ISC_FALSE;
 496
 497         if (message->rcode == dns_rcode_nxdomain)
 498                 return (ISC_FALSE);
 499
 500         /*
 501          * A DS RRset can appear anywhere in a zone, even for a delegation-only
 502          * zone.  So a response to an explicit query for this type should be
 503          * excluded from delegation-only fixup.
 504          *
 505          * SOA, NS, and DNSKEY can only exist at a zone apex, so a postive
 506          * response to a query for these types can never violate the
 507          * delegation-only assumption: if the query name is below a
 508          * zone cut, the response should normally be a referral, which should
 509          * be accepted; if the query name is below a zone cut but the server
 510          * happens to have authority for the zone of the query name, the
 511          * response is a (non-referral) answer.  But this does not violate
 512          * delegation-only because the query name must be in a different zone
 513          * due to the "apex-only" nature of these types.  Note that if the
 514          * remote server happens to have authority for a child zone of a
 515          * delegation-only zone, we may still incorrectly "fix" the response
 516          * with NXDOMAIN for queries for other types.  Unfortunately it's
 517          * generally impossible to differentiate this case from violation of
 518          * the delegation-only assumption.  Once the resolver learns the
 519          * correct zone cut, possibly via a separate query for an "apex-only"
 520          * type, queries for other types will be resolved correctly.
 521          *
 522          * A query for type ANY will be accepted if it hits an exceptional
 523          * type above in the answer section as it should be from a child
 524          * zone.
 525          *
 526          * Also accept answers with RRSIG records from the child zone.
 527          * Direct queries for RRSIG records should not be answered from
 528          * the parent zone.
 529          */
 530
 531         if (message->counts[DNS_SECTION_ANSWER] != 0 &&
 532             (fctx->type == dns_rdatatype_ns ||
 533              fctx->type == dns_rdatatype_ds ||
 534              fctx->type == dns_rdatatype_soa ||
 535              fctx->type == dns_rdatatype_any ||
 536              fctx->type == dns_rdatatype_rrsig ||
 537              fctx->type == dns_rdatatype_dnskey)) {
 538                 result = dns_message_firstname(message, DNS_SECTION_ANSWER);
 539                 while (result == ISC_R_SUCCESS) {
 540                         name = NULL;
 541                         dns_message_currentname(message, DNS_SECTION_ANSWER,
 542                                                 &name);
 543                         for (rdataset = ISC_LIST_HEAD(name->list);
 544                              rdataset != NULL;
 545                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
 546                                 if (!dns_name_equal(name, &fctx->name))
 547                                         continue;
 548                                 type = rdataset->type;
 549                                 /*
 550                                  * RRsig from child?
 551                                  */
 552                                 if (type == dns_rdatatype_rrsig &&
 553                                     rrsig_fromchildzone(fctx, rdataset))
 554                                         return (ISC_FALSE);
 555                                 /*
 556                                  * Direct query for apex records or DS.
 557                                  */
 558                                 if (fctx->type == type &&
 559                                     (type == dns_rdatatype_ds ||
 560                                      type == dns_rdatatype_ns ||
 561                                      type == dns_rdatatype_soa ||
 562                                      type == dns_rdatatype_dnskey))
 563                                         return (ISC_FALSE);
 564                                 /*
 565                                  * Indirect query for apex records or DS.
 566                                  */
 567                                 if (fctx->type == dns_rdatatype_any &&
 568                                     (type == dns_rdatatype_ns ||
 569                                      type == dns_rdatatype_ds ||
 570                                      type == dns_rdatatype_soa ||
 571                                      type == dns_rdatatype_dnskey))
 572                                         return (ISC_FALSE);
 573                         }
 574                         result = dns_message_nextname(message,
 575                                                       DNS_SECTION_ANSWER);
 576                 }
 577         }
 578
 579         /*
 580          * A NODATA response to a DS query?
 581          */
 582         if (fctx->type == dns_rdatatype_ds &&
 583             message->counts[DNS_SECTION_ANSWER] == 0)
 584                 return (ISC_FALSE);
 585
 586         /* Look for referral or indication of answer from child zone? */
 587         if (message->counts[DNS_SECTION_AUTHORITY] == 0)
 588                 goto munge;
 589
 590         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
 591         while (result == ISC_R_SUCCESS) {
 592                 name = NULL;
 593                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
 594                 for (rdataset = ISC_LIST_HEAD(name->list);
 595                      rdataset != NULL;
 596                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
 597                         type = rdataset->type;
 598                         if (type == dns_rdatatype_soa &&
 599                             dns_name_equal(name, domain))
 600                                 keep_auth = ISC_TRUE;
 601
 602                         if (type != dns_rdatatype_ns &&
 603                             type != dns_rdatatype_soa &&
 604                             type != dns_rdatatype_rrsig)
 605                                 continue;
 606
 607                         if (type == dns_rdatatype_rrsig) {
 608                                 if (rrsig_fromchildzone(fctx, rdataset))
 609                                         return (ISC_FALSE);
 610                                 else
 611                                         continue;
 612                         }
 613
 614                         /* NS or SOA records. */
 615                         if (dns_name_equal(name, domain)) {
 616                                 /*
 617                                  * If a query for ANY causes a negative
 618                                  * response, we can be sure that this is
 619                                  * an empty node.  For other type of queries
 620                                  * we cannot differentiate an empty node
 621                                  * from a node that just doesn't have that
 622                                  * type of record.  We only accept the former
 623                                  * case.
 624                                  */
 625                                 if (message->counts[DNS_SECTION_ANSWER] == 0 &&
 626                                     fctx->type == dns_rdatatype_any)
 627                                         return (ISC_FALSE);
 628                         } else if (dns_name_issubdomain(name, domain)) {
 629                                 /* Referral or answer from child zone. */
 630                                 return (ISC_FALSE);
 631                         }
 632                 }
 633                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
 634         }
 635
 636  munge:
 637         message->rcode = dns_rcode_nxdomain;
 638         message->counts[DNS_SECTION_ANSWER] = 0;
 639         if (!keep_auth)
 640                 message->counts[DNS_SECTION_AUTHORITY] = 0;
 641         message->counts[DNS_SECTION_ADDITIONAL] = 0;
 642         return (ISC_TRUE);
 643 }
 644
 645 static inline isc_result_t
 646 fctx_starttimer(fetchctx_t *fctx) {
 647         /*
 648          * Start the lifetime timer for fctx.
 649          *
 650          * This is also used for stopping the idle timer; in that
 651          * case we must purge events already posted to ensure that
 652          * no further idle events are delivered.
 653          */
 654         return (isc_timer_reset(fctx->timer, isc_timertype_once,
 655                                 &fctx->expires, NULL, ISC_TRUE));
 656 }
 657
 658 static inline void
 659 fctx_stoptimer(fetchctx_t *fctx) {
 660         isc_result_t result;
 661
 662         /*
 663          * We don't return a result if resetting the timer to inactive fails
 664          * since there's nothing to be done about it.  Resetting to inactive
 665          * should never fail anyway, since the code as currently written
 666          * cannot fail in that case.
 667          */
 668         result = isc_timer_reset(fctx->timer, isc_timertype_inactive,
 669                                   NULL, NULL, ISC_TRUE);
 670         if (result != ISC_R_SUCCESS) {
 671                 UNEXPECTED_ERROR(__FILE__, __LINE__,
 672                                  "isc_timer_reset(): %s",
 673                                  isc_result_totext(result));
 674         }
 675 }
 676
 677
 678 static inline isc_result_t
 679 fctx_startidletimer(fetchctx_t *fctx, isc_interval_t *interval) {
 680         /*
 681          * Start the idle timer for fctx.  The lifetime timer continues
 682          * to be in effect.
 683          */
 684         return (isc_timer_reset(fctx->timer, isc_timertype_once,
 685                                 &fctx->expires, interval, ISC_FALSE));
 686 }
 687
 688 /*
 689  * Stopping the idle timer is equivalent to calling fctx_starttimer(), but
 690  * we use fctx_stopidletimer for readability in the code below.
 691  */
 692 #define fctx_stopidletimer      fctx_starttimer
 693
 694
 695 static inline void
 696 resquery_destroy(resquery_t **queryp) {
 697         resquery_t *query;
 698
 699         REQUIRE(queryp != NULL);
 700         query = *queryp;
 701         REQUIRE(!ISC_LINK_LINKED(query, link));
 702
 703         INSIST(query->tcpsocket == NULL);
 704
 705         query->fctx->nqueries--;
 706         if (SHUTTINGDOWN(query->fctx))
 707                 maybe_destroy(query->fctx);     /* Locks bucket. */
 708         query->magic = 0;
 709         isc_mem_put(query->mctx, query, sizeof(*query));
 710         *queryp = NULL;
 711 }
 712
 713 static void
 714 fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
 715                  isc_time_t *finish, isc_boolean_t no_response)
 716 {
 717         fetchctx_t *fctx;
 718         resquery_t *query;
 719         unsigned int rtt, rttms;
 720         unsigned int factor;
 721         dns_adbfind_t *find;
 722         dns_adbaddrinfo_t *addrinfo;
 723         isc_socket_t *socket;
 724
 725         query = *queryp;
 726         fctx = query->fctx;
 727
 728         FCTXTRACE("cancelquery");
 729
 730         REQUIRE(!RESQUERY_CANCELED(query));
 731
 732         query->attributes |= RESQUERY_ATTR_CANCELED;
 733
 734         /*
 735          * Should we update the RTT?
 736          */
 737         if (finish != NULL || no_response) {
 738                 if (finish != NULL) {
 739                         /*
 740                          * We have both the start and finish times for this
 741                          * packet, so we can compute a real RTT.
 742                          */
 743                         rtt = (unsigned int)isc_time_microdiff(finish,
 744                                                                &query->start);
 745                         factor = DNS_ADB_RTTADJDEFAULT;
 746
 747                         rttms = rtt / 1000;
 748                         if (rttms < DNS_RESOLVER_QRYRTTCLASS0) {
 749                                 inc_stats(fctx->res,
 750                                           dns_resstatscounter_queryrtt0);
 751                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS1) {
 752                                 inc_stats(fctx->res,
 753                                           dns_resstatscounter_queryrtt1);
 754                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS2) {
 755                                 inc_stats(fctx->res,
 756                                           dns_resstatscounter_queryrtt2);
 757                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS3) {
 758                                 inc_stats(fctx->res,
 759                                           dns_resstatscounter_queryrtt3);
 760                         } else if (rttms < DNS_RESOLVER_QRYRTTCLASS4) {
 761                                 inc_stats(fctx->res,
 762                                           dns_resstatscounter_queryrtt4);
 763                         } else {
 764                                 inc_stats(fctx->res,
 765                                           dns_resstatscounter_queryrtt5);
 766                         }
 767                 } else {
 768                         /*
 769                          * We don't have an RTT for this query.  Maybe the
 770                          * packet was lost, or maybe this server is very
 771                          * slow.  We don't know.  Increase the RTT.
 772                          */
 773                         INSIST(no_response);
 774                         rtt = query->addrinfo->srtt + 200000;
 775                         if (rtt > 10000000)
 776                                 rtt = 10000000;
 777                         /*
 778                          * Replace the current RTT with our value.
 779                          */
 780                         factor = DNS_ADB_RTTADJREPLACE;
 781                 }
 782                 dns_adb_adjustsrtt(fctx->adb, query->addrinfo, rtt, factor);
 783         }
 784
 785         /*
 786          * Age RTTs of servers not tried.
 787          */
 788         factor = DNS_ADB_RTTADJAGE;
 789         if (finish != NULL)
 790                 for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
 791                      addrinfo != NULL;
 792                      addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 793                         if (UNMARKED(addrinfo))
 794                                 dns_adb_adjustsrtt(fctx->adb, addrinfo,
 795                                                    0, factor);
 796
 797         if (finish != NULL && TRIEDFIND(fctx))
 798                 for (find = ISC_LIST_HEAD(fctx->finds);
 799                      find != NULL;
 800                      find = ISC_LIST_NEXT(find, publink))
 801                         for (addrinfo = ISC_LIST_HEAD(find->list);
 802                              addrinfo != NULL;
 803                              addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 804                                 if (UNMARKED(addrinfo))
 805                                         dns_adb_adjustsrtt(fctx->adb, addrinfo,
 806                                                            0, factor);
 807
 808         if (finish != NULL && TRIEDALT(fctx)) {
 809                 for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
 810                      addrinfo != NULL;
 811                      addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 812                         if (UNMARKED(addrinfo))
 813                                 dns_adb_adjustsrtt(fctx->adb, addrinfo,
 814                                                    0, factor);
 815                 for (find = ISC_LIST_HEAD(fctx->altfinds);
 816                      find != NULL;
 817                      find = ISC_LIST_NEXT(find, publink))
 818                         for (addrinfo = ISC_LIST_HEAD(find->list);
 819                              addrinfo != NULL;
 820                              addrinfo = ISC_LIST_NEXT(addrinfo, publink))
 821                                 if (UNMARKED(addrinfo))
 822                                         dns_adb_adjustsrtt(fctx->adb, addrinfo,
 823                                                            0, factor);
 824         }
 825
 826         /*
 827          * Check for any outstanding socket events.  If they exist, cancel
 828          * them and let the event handlers finish the cleanup.  The resolver
 829          * only needs to worry about managing the connect and send events;
 830          * the dispatcher manages the recv events.
 831          */
 832         if (RESQUERY_CONNECTING(query)) {
 833                 /*
 834                  * Cancel the connect.
 835                  */
 836                 if (query->tcpsocket != NULL) {
 837                         isc_socket_cancel(query->tcpsocket, NULL,
 838                                           ISC_SOCKCANCEL_CONNECT);
 839                 } else if (query->dispentry != NULL) {
 840                         INSIST(query->exclusivesocket);
 841                         socket = dns_dispatch_getentrysocket(query->dispentry);
 842                         if (socket != NULL)
 843                                 isc_socket_cancel(socket, NULL,
 844                                                   ISC_SOCKCANCEL_CONNECT);
 845                 }
 846         } else if (RESQUERY_SENDING(query)) {
 847                 /*
 848                  * Cancel the pending send.
 849                  */
 850                 if (query->exclusivesocket && query->dispentry != NULL)
 851                         socket = dns_dispatch_getentrysocket(query->dispentry);
 852                 else
 853                         socket = dns_dispatch_getsocket(query->dispatch);
 854                 if (socket != NULL)
 855                         isc_socket_cancel(socket, NULL, ISC_SOCKCANCEL_SEND);
 856         }
 857
 858         if (query->dispentry != NULL)
 859                 dns_dispatch_removeresponse(&query->dispentry, deventp);
 860
 861         ISC_LIST_UNLINK(fctx->queries, query, link);
 862
 863         if (query->tsig != NULL)
 864                 isc_buffer_free(&query->tsig);
 865
 866         if (query->tsigkey != NULL)
 867                 dns_tsigkey_detach(&query->tsigkey);
 868
 869         if (query->dispatch != NULL)
 870                 dns_dispatch_detach(&query->dispatch);
 871
 872         if (! (RESQUERY_CONNECTING(query) || RESQUERY_SENDING(query)))
 873                 /*
 874                  * It's safe to destroy the query now.
 875                  */
 876                 resquery_destroy(&query);
 877 }
 878
 879 static void
 880 fctx_cancelqueries(fetchctx_t *fctx, isc_boolean_t no_response) {
 881         resquery_t *query, *next_query;
 882
 883         FCTXTRACE("cancelqueries");
 884
 885         for (query = ISC_LIST_HEAD(fctx->queries);
 886              query != NULL;
 887              query = next_query) {
 888                 next_query = ISC_LIST_NEXT(query, link);
 889                 fctx_cancelquery(&query, NULL, NULL, no_response);
 890         }
 891 }
 892
 893 static void
 894 fctx_cleanupfinds(fetchctx_t *fctx) {
 895         dns_adbfind_t *find, *next_find;
 896
 897         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
 898
 899         for (find = ISC_LIST_HEAD(fctx->finds);
 900              find != NULL;
 901              find = next_find) {
 902                 next_find = ISC_LIST_NEXT(find, publink);
 903                 ISC_LIST_UNLINK(fctx->finds, find, publink);
 904                 dns_adb_destroyfind(&find);
 905         }
 906         fctx->find = NULL;
 907 }
 908
 909 static void
 910 fctx_cleanupaltfinds(fetchctx_t *fctx) {
 911         dns_adbfind_t *find, *next_find;
 912
 913         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
 914
 915         for (find = ISC_LIST_HEAD(fctx->altfinds);
 916              find != NULL;
 917              find = next_find) {
 918                 next_find = ISC_LIST_NEXT(find, publink);
 919                 ISC_LIST_UNLINK(fctx->altfinds, find, publink);
 920                 dns_adb_destroyfind(&find);
 921         }
 922         fctx->altfind = NULL;
 923 }
 924
 925 static void
 926 fctx_cleanupforwaddrs(fetchctx_t *fctx) {
 927         dns_adbaddrinfo_t *addr, *next_addr;
 928
 929         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
 930
 931         for (addr = ISC_LIST_HEAD(fctx->forwaddrs);
 932              addr != NULL;
 933              addr = next_addr) {
 934                 next_addr = ISC_LIST_NEXT(addr, publink);
 935                 ISC_LIST_UNLINK(fctx->forwaddrs, addr, publink);
 936                 dns_adb_freeaddrinfo(fctx->adb, &addr);
 937         }
 938 }
 939
 940 static void
 941 fctx_cleanupaltaddrs(fetchctx_t *fctx) {
 942         dns_adbaddrinfo_t *addr, *next_addr;
 943
 944         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
 945
 946         for (addr = ISC_LIST_HEAD(fctx->altaddrs);
 947              addr != NULL;
 948              addr = next_addr) {
 949                 next_addr = ISC_LIST_NEXT(addr, publink);
 950                 ISC_LIST_UNLINK(fctx->altaddrs, addr, publink);
 951                 dns_adb_freeaddrinfo(fctx->adb, &addr);
 952         }
 953 }
 954
 955 static inline void
 956 fctx_stopeverything(fetchctx_t *fctx, isc_boolean_t no_response) {
 957         FCTXTRACE("stopeverything");
 958         fctx_cancelqueries(fctx, no_response);
 959         fctx_cleanupfinds(fctx);
 960         fctx_cleanupaltfinds(fctx);
 961         fctx_cleanupforwaddrs(fctx);
 962         fctx_cleanupaltaddrs(fctx);
 963         fctx_stoptimer(fctx);
 964 }
 965
 966 static inline void
 967 fctx_sendevents(fetchctx_t *fctx, isc_result_t result, int line) {
 968         dns_fetchevent_t *event, *next_event;
 969         isc_task_t *task;
 970         unsigned int count = 0;
 971         isc_interval_t i;
 972         isc_boolean_t logit = ISC_FALSE;
 973         isc_time_t now;
 974         unsigned int old_spillat;
 975         unsigned int new_spillat = 0;   /* initialized to silence
 976                                            compiler warnings */
 977
 978         /*
 979          * Caller must be holding the appropriate bucket lock.
 980          */
 981         REQUIRE(fctx->state == fetchstate_done);
 982
 983         FCTXTRACE("sendevents");
 984
 985         /*
 986          * Keep some record of fetch result for logging later (if required).
 987          */
 988         fctx->result = result;
 989         fctx->exitline = line;
 990         TIME_NOW(&now);
 991         fctx->duration = isc_time_microdiff(&now, &fctx->start);
 992
 993         for (event = ISC_LIST_HEAD(fctx->events);
 994              event != NULL;
 995              event = next_event) {
 996                 next_event = ISC_LIST_NEXT(event, ev_link);
 997                 ISC_LIST_UNLINK(fctx->events, event, ev_link);
 998                 task = event->ev_sender;
 999                 event->ev_sender = fctx;
1000                 if (!HAVE_ANSWER(fctx))
1001                         event->result = result;
1002
1003                 INSIST(result != ISC_R_SUCCESS ||
1004                        dns_rdataset_isassociated(event->rdataset) ||
1005                        fctx->type == dns_rdatatype_any ||
1006                        fctx->type == dns_rdatatype_rrsig ||
1007                        fctx->type == dns_rdatatype_sig);
1008
1009                 /*
1010                  * Negative results must be indicated in event->result.
1011                  */
1012                 if (dns_rdataset_isassociated(event->rdataset) &&
1013                     event->rdataset->type == dns_rdatatype_none) {
1014                         INSIST(event->result == DNS_R_NCACHENXDOMAIN ||
1015                                event->result == DNS_R_NCACHENXRRSET);
1016                 }
1017
1018                 isc_task_sendanddetach(&task, ISC_EVENT_PTR(&event));
1019                 count++;
1020         }
1021
1022         if ((fctx->attributes & FCTX_ATTR_HAVEANSWER) != 0 &&
1023             fctx->spilled &&
1024             (count < fctx->res->spillatmax || fctx->res->spillatmax == 0)) {
1025                 LOCK(&fctx->res->lock);
1026                 if (count == fctx->res->spillat && !fctx->res->exiting) {
1027                         old_spillat = fctx->res->spillat;
1028                         fctx->res->spillat += 5;
1029                         if (fctx->res->spillat > fctx->res->spillatmax &&
1030                             fctx->res->spillatmax != 0)
1031                                 fctx->res->spillat = fctx->res->spillatmax;
1032                         new_spillat = fctx->res->spillat;
1033                         if (new_spillat != old_spillat) {
1034                                 logit = ISC_TRUE;
1035                         }
1036                         isc_interval_set(&i, 20 * 60, 0);
1037                         result = isc_timer_reset(fctx->res->spillattimer,
1038                                                  isc_timertype_ticker, NULL,
1039                                                  &i, ISC_TRUE);
1040                         RUNTIME_CHECK(result == ISC_R_SUCCESS);
1041                 }
1042                 UNLOCK(&fctx->res->lock);
1043                 if (logit)
1044                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
1045                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
1046                                       "clients-per-query increased to %u",
1047                                       new_spillat);
1048         }
1049 }
1050
1051 static inline void
1052 log_edns(fetchctx_t *fctx) {
1053         char domainbuf[DNS_NAME_FORMATSIZE];
1054
1055         if (fctx->reason == NULL)
1056                 return;
1057
1058         dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
1059         isc_log_write(dns_lctx, DNS_LOGCATEGORY_EDNS_DISABLED,
1060                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
1061                       "too many timeouts resolving '%s' (in '%s'?): %s",
1062                       fctx->info, domainbuf, fctx->reason);
1063
1064         fctx->reason = NULL;
1065 }
1066
1067 static void
1068 fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
1069         dns_resolver_t *res;
1070         isc_boolean_t no_response;
1071
1072         REQUIRE(line >= 0);
1073
1074         FCTXTRACE("done");
1075
1076         res = fctx->res;
1077
1078         if (result == ISC_R_SUCCESS) {
1079                 /*%
1080                  * Log any deferred EDNS timeout messages.
1081                  */
1082                 log_edns(fctx);
1083                 no_response = ISC_TRUE;
1084          } else
1085                 no_response = ISC_FALSE;
1086
1087         fctx->reason = NULL;
1088         fctx_stopeverything(fctx, no_response);
1089
1090         LOCK(&res->buckets[fctx->bucketnum].lock);
1091
1092         fctx->state = fetchstate_done;
1093         fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
1094         fctx_sendevents(fctx, result, line);
1095
1096         UNLOCK(&res->buckets[fctx->bucketnum].lock);
1097 }
1098
1099 static void
1100 process_sendevent(resquery_t *query, isc_event_t *event) {
1101         isc_socketevent_t *sevent = (isc_socketevent_t *)event;
1102         isc_boolean_t retry = ISC_FALSE;
1103         isc_result_t result;
1104         fetchctx_t *fctx;
1105
1106         fctx = query->fctx;
1107
1108         if (RESQUERY_CANCELED(query)) {
1109                 if (query->sends == 0 && query->connects == 0) {
1110                         /*
1111                          * This query was canceled while the
1112                          * isc_socket_sendto/connect() was in progress.
1113                          */
1114                         if (query->tcpsocket != NULL)
1115                                 isc_socket_detach(&query->tcpsocket);
1116                         resquery_destroy(&query);
1117                 }
1118         } else {
1119                 switch (sevent->result) {
1120                 case ISC_R_SUCCESS:
1121                         break;
1122
1123                 case ISC_R_HOSTUNREACH:
1124                 case ISC_R_NETUNREACH:
1125                 case ISC_R_NOPERM:
1126                 case ISC_R_ADDRNOTAVAIL:
1127                 case ISC_R_CONNREFUSED:
1128
1129                         /*
1130                          * No route to remote.
1131                          */
1132                         add_bad(fctx, query->addrinfo, sevent->result,
1133                                 badns_unreachable);
1134                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
1135                         retry = ISC_TRUE;
1136                         break;
1137
1138                 default:
1139                         fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
1140                         break;
1141                 }
1142         }
1143
1144         isc_event_free(&event);
1145
1146         if (retry) {
1147                 /*
1148                  * Behave as if the idle timer has expired.  For TCP
1149                  * this may not actually reflect the latest timer.
1150                  */
1151                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
1152                 result = fctx_stopidletimer(fctx);
1153                 if (result != ISC_R_SUCCESS)
1154                         fctx_done(fctx, result, __LINE__);
1155                 else
1156                         fctx_try(fctx, ISC_TRUE);
1157         }
1158 }
1159
1160 static void
1161 resquery_udpconnected(isc_task_t *task, isc_event_t *event) {
1162         resquery_t *query = event->ev_arg;
1163
1164         REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
1165
1166         QTRACE("udpconnected");
1167
1168         UNUSED(task);
1169
1170         INSIST(RESQUERY_CONNECTING(query));
1171
1172         query->connects--;
1173
1174         process_sendevent(query, event);
1175 }
1176
1177 static void
1178 resquery_senddone(isc_task_t *task, isc_event_t *event) {
1179         resquery_t *query = event->ev_arg;
1180
1181         REQUIRE(event->ev_type == ISC_SOCKEVENT_SENDDONE);
1182
1183         QTRACE("senddone");
1184
1185         /*
1186          * XXXRTH
1187          *
1188          * Currently we don't wait for the senddone event before retrying
1189          * a query.  This means that if we get really behind, we may end
1190          * up doing extra work!
1191          */
1192
1193         UNUSED(task);
1194
1195         INSIST(RESQUERY_SENDING(query));
1196
1197         query->sends--;
1198
1199         process_sendevent(query, event);
1200 }
1201
1202 static inline isc_result_t
1203 fctx_addopt(dns_message_t *message, unsigned int version,
1204             isc_uint16_t udpsize, isc_boolean_t request_nsid)
1205 {
1206         dns_rdataset_t *rdataset;
1207         dns_rdatalist_t *rdatalist;
1208         dns_rdata_t *rdata;
1209         isc_result_t result;
1210
1211         rdatalist = NULL;
1212         result = dns_message_gettemprdatalist(message, &rdatalist);
1213         if (result != ISC_R_SUCCESS)
1214                 return (result);
1215         rdata = NULL;
1216         result = dns_message_gettemprdata(message, &rdata);
1217         if (result != ISC_R_SUCCESS)
1218                 return (result);
1219         rdataset = NULL;
1220         result = dns_message_gettemprdataset(message, &rdataset);
1221         if (result != ISC_R_SUCCESS)
1222                 return (result);
1223         dns_rdataset_init(rdataset);
1224
1225         rdatalist->type = dns_rdatatype_opt;
1226         rdatalist->covers = 0;
1227
1228         /*
1229          * Set Maximum UDP buffer size.
1230          */
1231         rdatalist->rdclass = udpsize;
1232
1233         /*
1234          * Set EXTENDED-RCODE and Z to 0, DO to 1.
1235          */
1236         rdatalist->ttl = (version << 16);
1237         rdatalist->ttl |= DNS_MESSAGEEXTFLAG_DO;
1238
1239         /*
1240          * Set EDNS options if applicable
1241          */
1242         if (request_nsid) {
1243                 /* Send empty NSID option (RFC5001) */
1244                 unsigned char data[4];
1245                 isc_buffer_t buf;
1246
1247                 isc_buffer_init(&buf, data, sizeof(data));
1248                 isc_buffer_putuint16(&buf, DNS_OPT_NSID);
1249                 isc_buffer_putuint16(&buf, 0);
1250                 rdata->data = data;
1251                 rdata->length = sizeof(data);
1252         } else {
1253                 rdata->data = NULL;
1254                 rdata->length = 0;
1255         }
1256
1257         rdata->rdclass = rdatalist->rdclass;
1258         rdata->type = rdatalist->type;
1259         rdata->flags = 0;
1260
1261         ISC_LIST_INIT(rdatalist->rdata);
1262         ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
1263         RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist, rdataset) == ISC_R_SUCCESS);
1264
1265         return (dns_message_setopt(message, rdataset));
1266 }
1267
1268 static inline void
1269 fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
1270         unsigned int seconds;
1271         unsigned int us;
1272
1273         /*
1274          * We retry every .8 seconds the first two times through the address
1275          * list, and then we do exponential back-off.
1276          */
1277         if (fctx->restarts < 3)
1278                 us = 800000;
1279         else
1280                 us = (800000 << (fctx->restarts - 2));
1281
1282         /*
1283          * Double the round-trip time.
1284          */
1285         rtt *= 2;
1286
1287         /*
1288          * Always wait for at least the doubled round-trip time.
1289          */
1290         if (us < rtt)
1291                 us = rtt;
1292
1293         /*
1294          * But don't ever wait for more than 10 seconds.
1295          */
1296         if (us > 10000000)
1297                 us = 10000000;
1298
1299         seconds = us / 1000000;
1300         us -= seconds * 1000000;
1301         isc_interval_set(&fctx->interval, seconds, us * 1000);
1302 }
1303
1304 static isc_result_t
1305 fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
1306            unsigned int options)
1307 {
1308         dns_resolver_t *res;
1309         isc_task_t *task;
1310         isc_result_t result;
1311         resquery_t *query;
1312         isc_sockaddr_t addr;
1313         isc_boolean_t have_addr = ISC_FALSE;
1314
1315         FCTXTRACE("query");
1316
1317         res = fctx->res;
1318         task = res->buckets[fctx->bucketnum].task;
1319
1320         fctx_setretryinterval(fctx, addrinfo->srtt);
1321         result = fctx_startidletimer(fctx, &fctx->interval);
1322         if (result != ISC_R_SUCCESS)
1323                 return (result);
1324
1325         INSIST(ISC_LIST_EMPTY(fctx->validators));
1326
1327         dns_message_reset(fctx->rmessage, DNS_MESSAGE_INTENTPARSE);
1328
1329         query = isc_mem_get(res->buckets[fctx->bucketnum].mctx,
1330                             sizeof(*query));
1331         if (query == NULL) {
1332                 result = ISC_R_NOMEMORY;
1333                 goto stop_idle_timer;
1334         }
1335         query->mctx = res->buckets[fctx->bucketnum].mctx;
1336         query->options = options;
1337         query->attributes = 0;
1338         query->sends = 0;
1339         query->connects = 0;
1340         /*
1341          * Note that the caller MUST guarantee that 'addrinfo' will remain
1342          * valid until this query is canceled.
1343          */
1344         query->addrinfo = addrinfo;
1345         TIME_NOW(&query->start);
1346
1347         /*
1348          * If this is a TCP query, then we need to make a socket and
1349          * a dispatch for it here.  Otherwise we use the resolver's
1350          * shared dispatch.
1351          */
1352         query->dispatchmgr = res->dispatchmgr;
1353         query->dispatch = NULL;
1354         query->exclusivesocket = ISC_FALSE;
1355         query->tcpsocket = NULL;
1356         if (res->view->peers != NULL) {
1357                 dns_peer_t *peer = NULL;
1358                 isc_netaddr_t dstip;
1359                 isc_netaddr_fromsockaddr(&dstip, &addrinfo->sockaddr);
1360                 result = dns_peerlist_peerbyaddr(res->view->peers,
1361                                                  &dstip, &peer);
1362                 if (result == ISC_R_SUCCESS) {
1363                         result = dns_peer_getquerysource(peer, &addr);
1364                         if (result == ISC_R_SUCCESS)
1365                                 have_addr = ISC_TRUE;
1366                 }
1367         }
1368
1369         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1370                 int pf;
1371
1372                 pf = isc_sockaddr_pf(&addrinfo->sockaddr);
1373                 if (!have_addr) {
1374                         switch (pf) {
1375                         case PF_INET:
1376                                 result =
1377                                   dns_dispatch_getlocaladdress(res->dispatchv4,
1378                                                                &addr);
1379                                 break;
1380                         case PF_INET6:
1381                                 result =
1382                                   dns_dispatch_getlocaladdress(res->dispatchv6,
1383                                                                &addr);
1384                                 break;
1385                         default:
1386                                 result = ISC_R_NOTIMPLEMENTED;
1387                                 break;
1388                         }
1389                         if (result != ISC_R_SUCCESS)
1390                                 goto cleanup_query;
1391                 }
1392                 isc_sockaddr_setport(&addr, 0);
1393
1394                 result = isc_socket_create(res->socketmgr, pf,
1395                                            isc_sockettype_tcp,
1396                                            &query->tcpsocket);
1397                 if (result != ISC_R_SUCCESS)
1398                         goto cleanup_query;
1399
1400 #ifndef BROKEN_TCP_BIND_BEFORE_CONNECT
1401                 result = isc_socket_bind(query->tcpsocket, &addr, 0);
1402                 if (result != ISC_R_SUCCESS)
1403                         goto cleanup_socket;
1404 #endif
1405
1406                 /*
1407                  * A dispatch will be created once the connect succeeds.
1408                  */
1409         } else {
1410                 if (have_addr) {
1411                         unsigned int attrs, attrmask;
1412                         attrs = DNS_DISPATCHATTR_UDP;
1413                         switch (isc_sockaddr_pf(&addr)) {
1414                         case AF_INET:
1415                                 attrs |= DNS_DISPATCHATTR_IPV4;
1416                                 break;
1417                         case AF_INET6:
1418                                 attrs |= DNS_DISPATCHATTR_IPV6;
1419                                 break;
1420                         default:
1421                                 result = ISC_R_NOTIMPLEMENTED;
1422                                 goto cleanup_query;
1423                         }
1424                         attrmask = DNS_DISPATCHATTR_UDP;
1425                         attrmask |= DNS_DISPATCHATTR_TCP;
1426                         attrmask |= DNS_DISPATCHATTR_IPV4;
1427                         attrmask |= DNS_DISPATCHATTR_IPV6;
1428                         result = dns_dispatch_getudp(res->dispatchmgr,
1429                                                      res->socketmgr,
1430                                                      res->taskmgr, &addr,
1431                                                      4096, 1000, 32768, 16411,
1432                                                      16433, attrs, attrmask,
1433                                                      &query->dispatch);
1434                         if (result != ISC_R_SUCCESS)
1435                                 goto cleanup_query;
1436                 } else {
1437                         switch (isc_sockaddr_pf(&addrinfo->sockaddr)) {
1438                         case PF_INET:
1439                                 dns_dispatch_attach(res->dispatchv4,
1440                                                     &query->dispatch);
1441                                 query->exclusivesocket = res->exclusivev4;
1442                                 break;
1443                         case PF_INET6:
1444                                 dns_dispatch_attach(res->dispatchv6,
1445                                                     &query->dispatch);
1446                                 query->exclusivesocket = res->exclusivev6;
1447                                 break;
1448                         default:
1449                                 result = ISC_R_NOTIMPLEMENTED;
1450                                 goto cleanup_query;
1451                         }
1452                 }
1453                 /*
1454                  * We should always have a valid dispatcher here.  If we
1455                  * don't support a protocol family, then its dispatcher
1456                  * will be NULL, but we shouldn't be finding addresses for
1457                  * protocol types we don't support, so the dispatcher
1458                  * we found should never be NULL.
1459                  */
1460                 INSIST(query->dispatch != NULL);
1461         }
1462
1463         query->dispentry = NULL;
1464         query->fctx = fctx;
1465         query->tsig = NULL;
1466         query->tsigkey = NULL;
1467         ISC_LINK_INIT(query, link);
1468         query->magic = QUERY_MAGIC;
1469
1470         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1471                 /*
1472                  * Connect to the remote server.
1473                  *
1474                  * XXXRTH  Should we attach to the socket?
1475                  */
1476                 result = isc_socket_connect(query->tcpsocket,
1477                                             &addrinfo->sockaddr, task,
1478                                             resquery_connected, query);
1479                 if (result != ISC_R_SUCCESS)
1480                         goto cleanup_socket;
1481                 query->connects++;
1482                 QTRACE("connecting via TCP");
1483         } else {
1484                 result = resquery_send(query);
1485                 if (result != ISC_R_SUCCESS)
1486                         goto cleanup_dispatch;
1487         }
1488         fctx->querysent++;
1489
1490         ISC_LIST_APPEND(fctx->queries, query, link);
1491         query->fctx->nqueries++;
1492         if (isc_sockaddr_pf(&addrinfo->sockaddr) == PF_INET)
1493                 inc_stats(res, dns_resstatscounter_queryv4);
1494         else
1495                 inc_stats(res, dns_resstatscounter_queryv6);
1496         if (res->view->resquerystats != NULL)
1497                 dns_rdatatypestats_increment(res->view->resquerystats,
1498                                              fctx->type);
1499
1500         return (ISC_R_SUCCESS);
1501
1502  cleanup_socket:
1503         isc_socket_detach(&query->tcpsocket);
1504
1505  cleanup_dispatch:
1506         if (query->dispatch != NULL)
1507                 dns_dispatch_detach(&query->dispatch);
1508
1509  cleanup_query:
1510         query->magic = 0;
1511         isc_mem_put(res->buckets[fctx->bucketnum].mctx,
1512                     query, sizeof(*query));
1513
1514  stop_idle_timer:
1515         RUNTIME_CHECK(fctx_stopidletimer(fctx) == ISC_R_SUCCESS);
1516
1517         return (result);
1518 }
1519
1520 static isc_boolean_t
1521 triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1522         isc_sockaddr_t *sa;
1523
1524         for (sa = ISC_LIST_HEAD(fctx->edns);
1525              sa != NULL;
1526              sa = ISC_LIST_NEXT(sa, link)) {
1527                 if (isc_sockaddr_equal(sa, address))
1528                         return (ISC_TRUE);
1529         }
1530
1531         return (ISC_FALSE);
1532 }
1533
1534 static void
1535 add_triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
1536         isc_sockaddr_t *sa;
1537
1538         if (triededns(fctx, address))
1539                 return;
1540
1541         sa = isc_mem_get(fctx->res->buckets[fctx->bucketnum].mctx,
1542                          sizeof(*sa));
1543         if (sa == NULL)
1544                 return;
1545
1546         *sa = *address;
1547         ISC_LIST_INITANDAPPEND(fctx->edns, sa, link);
1548 }
1549
1550 static isc_boolean_t
1551 triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
1552         isc_sockaddr_t *sa;
1553
1554         for (sa = ISC_LIST_HEAD(fctx->edns512);
1555              sa != NULL;
1556              sa = ISC_LIST_NEXT(sa, link)) {
1557                 if (isc_sockaddr_equal(sa, address))
1558                         return (ISC_TRUE);
1559         }
1560
1561         return (ISC_FALSE);
1562 }
1563
1564 static void
1565 add_triededns512(fetchctx_t *fctx, isc_sockaddr_t *address) {
1566         isc_sockaddr_t *sa;
1567
1568         if (triededns512(fctx, address))
1569                 return;
1570
1571         sa = isc_mem_get(fctx->res->buckets[fctx->bucketnum].mctx,
1572                          sizeof(*sa));
1573         if (sa == NULL)
1574                 return;
1575
1576         *sa = *address;
1577         ISC_LIST_INITANDAPPEND(fctx->edns512, sa, link);
1578 }
1579
1580 static isc_result_t
1581 resquery_send(resquery_t *query) {
1582         fetchctx_t *fctx;
1583         isc_result_t result;
1584         dns_name_t *qname = NULL;
1585         dns_rdataset_t *qrdataset = NULL;
1586         isc_region_t r;
1587         dns_resolver_t *res;
1588         isc_task_t *task;
1589         isc_socket_t *socket;
1590         isc_buffer_t tcpbuffer;
1591         isc_sockaddr_t *address;
1592         isc_buffer_t *buffer;
1593         isc_netaddr_t ipaddr;
1594         dns_tsigkey_t *tsigkey = NULL;
1595         dns_peer_t *peer = NULL;
1596         isc_boolean_t useedns;
1597         dns_compress_t cctx;
1598         isc_boolean_t cleanup_cctx = ISC_FALSE;
1599         isc_boolean_t secure_domain;
1600
1601         fctx = query->fctx;
1602         QTRACE("send");
1603
1604         res = fctx->res;
1605         task = res->buckets[fctx->bucketnum].task;
1606         address = NULL;
1607
1608         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1609                 /*
1610                  * Reserve space for the TCP message length.
1611                  */
1612                 isc_buffer_init(&tcpbuffer, query->data, sizeof(query->data));
1613                 isc_buffer_init(&query->buffer, query->data + 2,
1614                                 sizeof(query->data) - 2);
1615                 buffer = &tcpbuffer;
1616         } else {
1617                 isc_buffer_init(&query->buffer, query->data,
1618                                 sizeof(query->data));
1619                 buffer = &query->buffer;
1620         }
1621
1622         result = dns_message_gettempname(fctx->qmessage, &qname);
1623         if (result != ISC_R_SUCCESS)
1624                 goto cleanup_temps;
1625         result = dns_message_gettemprdataset(fctx->qmessage, &qrdataset);
1626         if (result != ISC_R_SUCCESS)
1627                 goto cleanup_temps;
1628
1629         /*
1630          * Get a query id from the dispatch.
1631          */
1632         result = dns_dispatch_addresponse2(query->dispatch,
1633                                            &query->addrinfo->sockaddr,
1634                                            task,
1635                                            resquery_response,
1636                                            query,
1637                                            &query->id,
1638                                            &query->dispentry,
1639                                            res->socketmgr);
1640         if (result != ISC_R_SUCCESS)
1641                 goto cleanup_temps;
1642
1643         fctx->qmessage->opcode = dns_opcode_query;
1644
1645         /*
1646          * Set up question.
1647          */
1648         dns_name_init(qname, NULL);
1649         dns_name_clone(&fctx->name, qname);
1650         dns_rdataset_init(qrdataset);
1651         dns_rdataset_makequestion(qrdataset, res->rdclass, fctx->type);
1652         ISC_LIST_APPEND(qname->list, qrdataset, link);
1653         dns_message_addname(fctx->qmessage, qname, DNS_SECTION_QUESTION);
1654         qname = NULL;
1655         qrdataset = NULL;
1656
1657         /*
1658          * Set RD if the client has requested that we do a recursive query,
1659          * or if we're sending to a forwarder.
1660          */
1661         if ((query->options & DNS_FETCHOPT_RECURSIVE) != 0 ||
1662             ISFORWARDER(query->addrinfo))
1663                 fctx->qmessage->flags |= DNS_MESSAGEFLAG_RD;
1664
1665         /*
1666          * Set CD if the client says don't validate or the question is
1667          * under a secure entry point.
1668          */
1669         if ((query->options & DNS_FETCHOPT_NOVALIDATE) != 0) {
1670                 fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
1671         } else if (res->view->enablevalidation) {
1672                 result = dns_keytable_issecuredomain(res->view->secroots,
1673                                                      &fctx->name,
1674                                                      &secure_domain);
1675                 if (result != ISC_R_SUCCESS)
1676                         secure_domain = ISC_FALSE;
1677                 if (res->view->dlv != NULL)
1678                         secure_domain = ISC_TRUE;
1679                 if (secure_domain)
1680                         fctx->qmessage->flags |= DNS_MESSAGEFLAG_CD;
1681         }
1682
1683         /*
1684          * We don't have to set opcode because it defaults to query.
1685          */
1686         fctx->qmessage->id = query->id;
1687
1688         /*
1689          * Convert the question to wire format.
1690          */
1691         result = dns_compress_init(&cctx, -1, fctx->res->mctx);
1692         if (result != ISC_R_SUCCESS)
1693                 goto cleanup_message;
1694         cleanup_cctx = ISC_TRUE;
1695
1696         result = dns_message_renderbegin(fctx->qmessage, &cctx,
1697                                          &query->buffer);
1698         if (result != ISC_R_SUCCESS)
1699                 goto cleanup_message;
1700
1701         result = dns_message_rendersection(fctx->qmessage,
1702                                            DNS_SECTION_QUESTION, 0);
1703         if (result != ISC_R_SUCCESS)
1704                 goto cleanup_message;
1705
1706         peer = NULL;
1707         isc_netaddr_fromsockaddr(&ipaddr, &query->addrinfo->sockaddr);
1708         (void) dns_peerlist_peerbyaddr(fctx->res->view->peers, &ipaddr, &peer);
1709
1710         /*
1711          * The ADB does not know about servers with "edns no".  Check this,
1712          * and then inform the ADB for future use.
1713          */
1714         if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0 &&
1715             peer != NULL &&
1716             dns_peer_getsupportedns(peer, &useedns) == ISC_R_SUCCESS &&
1717             !useedns)
1718         {
1719                 query->options |= DNS_FETCHOPT_NOEDNS0;
1720                 dns_adb_changeflags(fctx->adb, query->addrinfo,
1721                                     DNS_FETCHOPT_NOEDNS0,
1722                                     DNS_FETCHOPT_NOEDNS0);
1723         }
1724
1725         /* Sync NOEDNS0 flag in addrinfo->flags and options now. */
1726         if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) != 0)
1727                 query->options |= DNS_FETCHOPT_NOEDNS0;
1728
1729         /*
1730          * Handle timeouts by reducing the UDP response size to 512 bytes
1731          * then if that doesn't work disabling EDNS (includes DO) and CD.
1732          *
1733          * These timeout can be due to:
1734          *      * broken nameservers that don't respond to EDNS queries.
1735          *      * broken/misconfigured firewalls and NAT implementations
1736          *        that don't handle IP fragmentation.
1737          *      * broken/misconfigured firewalls that don't handle responses
1738          *        greater than 512 bytes.
1739          *      * broken/misconfigured firewalls that don't handle EDNS, DO
1740          *        or CD.
1741          *      * packet loss / link outage.
1742          */
1743         if (fctx->timeout) {
1744                 if ((triededns512(fctx, &query->addrinfo->sockaddr) ||
1745                      fctx->timeouts >= (MAX_EDNS0_TIMEOUTS * 2)) &&
1746                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1747                         query->options |= DNS_FETCHOPT_NOEDNS0;
1748                         fctx->reason = "disabling EDNS";
1749                 } else if ((triededns(fctx, &query->addrinfo->sockaddr) ||
1750                             fctx->timeouts >= MAX_EDNS0_TIMEOUTS) &&
1751                            (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1752                         query->options |= DNS_FETCHOPT_EDNS512;
1753                         fctx->reason = "reducing the advertised EDNS UDP "
1754                                        "packet size to 512 octets";
1755                 }
1756                 fctx->timeout = ISC_FALSE;
1757         }
1758
1759         /*
1760          * Use EDNS0, unless the caller doesn't want it, or we know that
1761          * the remote server doesn't like it.
1762          */
1763         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
1764                 if ((query->addrinfo->flags & DNS_FETCHOPT_NOEDNS0) == 0) {
1765                         unsigned int version = 0;       /* Default version. */
1766                         unsigned int flags;
1767                         isc_uint16_t udpsize = res->udpsize;
1768                         isc_boolean_t reqnsid = res->view->requestnsid;
1769
1770                         flags = query->addrinfo->flags;
1771                         if ((flags & DNS_FETCHOPT_EDNSVERSIONSET) != 0) {
1772                                 version = flags & DNS_FETCHOPT_EDNSVERSIONMASK;
1773                                 version >>= DNS_FETCHOPT_EDNSVERSIONSHIFT;
1774                         }
1775                         if ((query->options & DNS_FETCHOPT_EDNS512) != 0)
1776                                 udpsize = 512;
1777                         else if (peer != NULL)
1778                                 (void)dns_peer_getudpsize(peer, &udpsize);
1779
1780                         /* request NSID for current view or peer? */
1781                         if (peer != NULL)
1782                                 (void) dns_peer_getrequestnsid(peer, &reqnsid);
1783                         result = fctx_addopt(fctx->qmessage, version,
1784                                              udpsize, reqnsid);
1785                         if (reqnsid && result == ISC_R_SUCCESS) {
1786                                 query->options |= DNS_FETCHOPT_WANTNSID;
1787                         } else if (result != ISC_R_SUCCESS) {
1788                                 /*
1789                                  * We couldn't add the OPT, but we'll press on.
1790                                  * We're not using EDNS0, so set the NOEDNS0
1791                                  * bit.
1792                                  */
1793                                 query->options |= DNS_FETCHOPT_NOEDNS0;
1794                         }
1795                 } else {
1796                         /*
1797                          * We know this server doesn't like EDNS0, so we
1798                          * won't use it.  Set the NOEDNS0 bit since we're
1799                          * not using EDNS0.
1800                          */
1801                         query->options |= DNS_FETCHOPT_NOEDNS0;
1802                 }
1803         }
1804
1805         /*
1806          * If we need EDNS0 to do this query and aren't using it, we lose.
1807          */
1808         if (NEEDEDNS0(fctx) && (query->options & DNS_FETCHOPT_NOEDNS0) != 0) {
1809                 result = DNS_R_SERVFAIL;
1810                 goto cleanup_message;
1811         }
1812
1813         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0)
1814                 add_triededns(fctx, &query->addrinfo->sockaddr);
1815
1816         if ((query->options & DNS_FETCHOPT_EDNS512) != 0)
1817                 add_triededns512(fctx, &query->addrinfo->sockaddr);
1818
1819         /*
1820          * Clear CD if EDNS is not in use.
1821          */
1822         if ((query->options & DNS_FETCHOPT_NOEDNS0) != 0)
1823                 fctx->qmessage->flags &= ~DNS_MESSAGEFLAG_CD;
1824
1825         /*
1826          * Add TSIG record tailored to the current recipient.
1827          */
1828         result = dns_view_getpeertsig(fctx->res->view, &ipaddr, &tsigkey);
1829         if (result != ISC_R_SUCCESS && result != ISC_R_NOTFOUND)
1830                 goto cleanup_message;
1831
1832         if (tsigkey != NULL) {
1833                 result = dns_message_settsigkey(fctx->qmessage, tsigkey);
1834                 dns_tsigkey_detach(&tsigkey);
1835                 if (result != ISC_R_SUCCESS)
1836                         goto cleanup_message;
1837         }
1838
1839         result = dns_message_rendersection(fctx->qmessage,
1840                                            DNS_SECTION_ADDITIONAL, 0);
1841         if (result != ISC_R_SUCCESS)
1842                 goto cleanup_message;
1843
1844         result = dns_message_renderend(fctx->qmessage);
1845         if (result != ISC_R_SUCCESS)
1846                 goto cleanup_message;
1847
1848         dns_compress_invalidate(&cctx);
1849         cleanup_cctx = ISC_FALSE;
1850
1851         if (dns_message_gettsigkey(fctx->qmessage) != NULL) {
1852                 dns_tsigkey_attach(dns_message_gettsigkey(fctx->qmessage),
1853                                    &query->tsigkey);
1854                 result = dns_message_getquerytsig(fctx->qmessage,
1855                                                   fctx->res->mctx,
1856                                                   &query->tsig);
1857                 if (result != ISC_R_SUCCESS)
1858                         goto cleanup_message;
1859         }
1860
1861         /*
1862          * If using TCP, write the length of the message at the beginning
1863          * of the buffer.
1864          */
1865         if ((query->options & DNS_FETCHOPT_TCP) != 0) {
1866                 isc_buffer_usedregion(&query->buffer, &r);
1867                 isc_buffer_putuint16(&tcpbuffer, (isc_uint16_t)r.length);
1868                 isc_buffer_add(&tcpbuffer, r.length);
1869         }
1870
1871         /*
1872          * We're now done with the query message.
1873          */
1874         dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
1875
1876         if (query->exclusivesocket)
1877                 socket = dns_dispatch_getentrysocket(query->dispentry);
1878         else
1879                 socket = dns_dispatch_getsocket(query->dispatch);
1880         /*
1881          * Send the query!
1882          */
1883         if ((query->options & DNS_FETCHOPT_TCP) == 0) {
1884                 address = &query->addrinfo->sockaddr;
1885                 if (query->exclusivesocket) {
1886                         result = isc_socket_connect(socket, address, task,
1887                                                     resquery_udpconnected,
1888                                                     query);
1889                         if (result != ISC_R_SUCCESS)
1890                                 goto cleanup_message;
1891                         query->connects++;
1892                 }
1893         }
1894         isc_buffer_usedregion(buffer, &r);
1895
1896         /*
1897          * XXXRTH  Make sure we don't send to ourselves!  We should probably
1898          *              prune out these addresses when we get them from the ADB.
1899          */
1900         result = isc_socket_sendto(socket, &r, task, resquery_senddone,
1901                                    query, address, NULL);
1902         if (result != ISC_R_SUCCESS)
1903                 goto cleanup_message;
1904
1905         query->sends++;
1906
1907         QTRACE("sent");
1908
1909         return (ISC_R_SUCCESS);
1910
1911  cleanup_message:
1912         if (cleanup_cctx)
1913                 dns_compress_invalidate(&cctx);
1914
1915         dns_message_reset(fctx->qmessage, DNS_MESSAGE_INTENTRENDER);
1916
1917         /*
1918          * Stop the dispatcher from listening.
1919          */
1920         dns_dispatch_removeresponse(&query->dispentry, NULL);
1921
1922  cleanup_temps:
1923         if (qname != NULL)
1924                 dns_message_puttempname(fctx->qmessage, &qname);
1925         if (qrdataset != NULL)
1926                 dns_message_puttemprdataset(fctx->qmessage, &qrdataset);
1927
1928         return (result);
1929 }
1930
1931 static void
1932 resquery_connected(isc_task_t *task, isc_event_t *event) {
1933         isc_socketevent_t *sevent = (isc_socketevent_t *)event;
1934         resquery_t *query = event->ev_arg;
1935         isc_boolean_t retry = ISC_FALSE;
1936         isc_interval_t interval;
1937         isc_result_t result;
1938         unsigned int attrs;
1939         fetchctx_t *fctx;
1940
1941         REQUIRE(event->ev_type == ISC_SOCKEVENT_CONNECT);
1942         REQUIRE(VALID_QUERY(query));
1943
1944         QTRACE("connected");
1945
1946         UNUSED(task);
1947
1948         /*
1949          * XXXRTH
1950          *
1951          * Currently we don't wait for the connect event before retrying
1952          * a query.  This means that if we get really behind, we may end
1953          * up doing extra work!
1954          */
1955
1956         query->connects--;
1957         fctx = query->fctx;
1958
1959         if (RESQUERY_CANCELED(query)) {
1960                 /*
1961                  * This query was canceled while the connect() was in
1962                  * progress.
1963                  */
1964                 isc_socket_detach(&query->tcpsocket);
1965                 resquery_destroy(&query);
1966         } else {
1967                 switch (sevent->result) {
1968                 case ISC_R_SUCCESS:
1969
1970                         /*
1971                          * Extend the idle timer for TCP.  20 seconds
1972                          * should be long enough for a TCP connection to be
1973                          * established, a single DNS request to be sent,
1974                          * and the response received.
1975                          */
1976                         isc_interval_set(&interval, 20, 0);
1977                         result = fctx_startidletimer(query->fctx, &interval);
1978                         if (result != ISC_R_SUCCESS) {
1979                                 fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
1980                                 fctx_done(fctx, result, __LINE__);
1981                                 break;
1982                         }
1983                         /*
1984                          * We are connected.  Create a dispatcher and
1985                          * send the query.
1986                          */
1987                         attrs = 0;
1988                         attrs |= DNS_DISPATCHATTR_TCP;
1989                         attrs |= DNS_DISPATCHATTR_PRIVATE;
1990                         attrs |= DNS_DISPATCHATTR_CONNECTED;
1991                         if (isc_sockaddr_pf(&query->addrinfo->sockaddr) ==
1992                             AF_INET)
1993                                 attrs |= DNS_DISPATCHATTR_IPV4;
1994                         else
1995                                 attrs |= DNS_DISPATCHATTR_IPV6;
1996                         attrs |= DNS_DISPATCHATTR_MAKEQUERY;
1997
1998                         result = dns_dispatch_createtcp(query->dispatchmgr,
1999                                                      query->tcpsocket,
2000                                                      query->fctx->res->taskmgr,
2001                                                      4096, 2, 1, 1, 3, attrs,
2002                                                      &query->dispatch);
2003
2004                         /*
2005                          * Regardless of whether dns_dispatch_create()
2006                          * succeeded or not, we don't need our reference
2007                          * to the socket anymore.
2008                          */
2009                         isc_socket_detach(&query->tcpsocket);
2010
2011                         if (result == ISC_R_SUCCESS)
2012                                 result = resquery_send(query);
2013
2014                         if (result != ISC_R_SUCCESS) {
2015                                 fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
2016                                 fctx_done(fctx, result, __LINE__);
2017                         }
2018                         break;
2019
2020                 case ISC_R_NETUNREACH:
2021                 case ISC_R_HOSTUNREACH:
2022                 case ISC_R_CONNREFUSED:
2023                 case ISC_R_NOPERM:
2024                 case ISC_R_ADDRNOTAVAIL:
2025                 case ISC_R_CONNECTIONRESET:
2026                         /*
2027                          * No route to remote.
2028                          */
2029                         isc_socket_detach(&query->tcpsocket);
2030                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
2031                         retry = ISC_TRUE;
2032                         break;
2033
2034                 default:
2035                         isc_socket_detach(&query->tcpsocket);
2036                         fctx_cancelquery(&query, NULL, NULL, ISC_FALSE);
2037                         break;
2038                 }
2039         }
2040
2041         isc_event_free(&event);
2042
2043         if (retry) {
2044                 /*
2045                  * Behave as if the idle timer has expired.  For TCP
2046                  * connections this may not actually reflect the latest timer.
2047                  */
2048                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
2049                 result = fctx_stopidletimer(fctx);
2050                 if (result != ISC_R_SUCCESS)
2051                         fctx_done(fctx, result, __LINE__);
2052                 else
2053                         fctx_try(fctx, ISC_TRUE);
2054         }
2055 }
2056
2057 static void
2058 fctx_finddone(isc_task_t *task, isc_event_t *event) {
2059         fetchctx_t *fctx;
2060         dns_adbfind_t *find;
2061         dns_resolver_t *res;
2062         isc_boolean_t want_try = ISC_FALSE;
2063         isc_boolean_t want_done = ISC_FALSE;
2064         isc_boolean_t bucket_empty = ISC_FALSE;
2065         unsigned int bucketnum;
2066
2067         find = event->ev_sender;
2068         fctx = event->ev_arg;
2069         REQUIRE(VALID_FCTX(fctx));
2070         res = fctx->res;
2071
2072         UNUSED(task);
2073
2074         FCTXTRACE("finddone");
2075
2076         INSIST(fctx->pending > 0);
2077         fctx->pending--;
2078
2079         if (ADDRWAIT(fctx)) {
2080                 /*
2081                  * The fetch is waiting for a name to be found.
2082                  */
2083                 INSIST(!SHUTTINGDOWN(fctx));
2084                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
2085                 if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES)
2086                         want_try = ISC_TRUE;
2087                 else {
2088                         fctx->findfail++;
2089                         if (fctx->pending == 0) {
2090                                 /*
2091                                  * We've got nothing else to wait for and don't
2092                                  * know the answer.  There's nothing to do but
2093                                  * fail the fctx.
2094                                  */
2095                                 want_done = ISC_TRUE;
2096                         }
2097                 }
2098         } else if (SHUTTINGDOWN(fctx) && fctx->pending == 0 &&
2099                    fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators)) {
2100                 bucketnum = fctx->bucketnum;
2101                 LOCK(&res->buckets[bucketnum].lock);
2102                 /*
2103                  * Note that we had to wait until we had the lock before
2104                  * looking at fctx->references.
2105                  */
2106                 if (fctx->references == 0)
2107                         bucket_empty = fctx_destroy(fctx);
2108                 UNLOCK(&res->buckets[bucketnum].lock);
2109         }
2110
2111         isc_event_free(&event);
2112         dns_adb_destroyfind(&find);
2113
2114         if (want_try)
2115                 fctx_try(fctx, ISC_TRUE);
2116         else if (want_done)
2117                 fctx_done(fctx, ISC_R_FAILURE, __LINE__);
2118         else if (bucket_empty)
2119                 empty_bucket(res);
2120 }
2121
2122
2123 static inline isc_boolean_t
2124 bad_server(fetchctx_t *fctx, isc_sockaddr_t *address) {
2125         isc_sockaddr_t *sa;
2126
2127         for (sa = ISC_LIST_HEAD(fctx->bad);
2128              sa != NULL;
2129              sa = ISC_LIST_NEXT(sa, link)) {
2130                 if (isc_sockaddr_equal(sa, address))
2131                         return (ISC_TRUE);
2132         }
2133
2134         return (ISC_FALSE);
2135 }
2136
2137 static inline isc_boolean_t
2138 mark_bad(fetchctx_t *fctx) {
2139         dns_adbfind_t *curr;
2140         dns_adbaddrinfo_t *addrinfo;
2141         isc_boolean_t all_bad = ISC_TRUE;
2142
2143         /*
2144          * Mark all known bad servers, so we don't try to talk to them
2145          * again.
2146          */
2147
2148         /*
2149          * Mark any bad nameservers.
2150          */
2151         for (curr = ISC_LIST_HEAD(fctx->finds);
2152              curr != NULL;
2153              curr = ISC_LIST_NEXT(curr, publink)) {
2154                 for (addrinfo = ISC_LIST_HEAD(curr->list);
2155                      addrinfo != NULL;
2156                      addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2157                         if (bad_server(fctx, &addrinfo->sockaddr))
2158                                 addrinfo->flags |= FCTX_ADDRINFO_MARK;
2159                         else
2160                                 all_bad = ISC_FALSE;
2161                 }
2162         }
2163
2164         /*
2165          * Mark any bad forwarders.
2166          */
2167         for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
2168              addrinfo != NULL;
2169              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2170                 if (bad_server(fctx, &addrinfo->sockaddr))
2171                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2172                 else
2173                         all_bad = ISC_FALSE;
2174         }
2175
2176         /*
2177          * Mark any bad alternates.
2178          */
2179         for (curr = ISC_LIST_HEAD(fctx->altfinds);
2180              curr != NULL;
2181              curr = ISC_LIST_NEXT(curr, publink)) {
2182                 for (addrinfo = ISC_LIST_HEAD(curr->list);
2183                      addrinfo != NULL;
2184                      addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2185                         if (bad_server(fctx, &addrinfo->sockaddr))
2186                                 addrinfo->flags |= FCTX_ADDRINFO_MARK;
2187                         else
2188                                 all_bad = ISC_FALSE;
2189                 }
2190         }
2191
2192         for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
2193              addrinfo != NULL;
2194              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2195                 if (bad_server(fctx, &addrinfo->sockaddr))
2196                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2197                 else
2198                         all_bad = ISC_FALSE;
2199         }
2200
2201         return (all_bad);
2202 }
2203
2204 static void
2205 add_bad(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, isc_result_t reason,
2206         badnstype_t badtype)
2207 {
2208         char namebuf[DNS_NAME_FORMATSIZE];
2209         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
2210         char classbuf[64];
2211         char typebuf[64];
2212         char code[64];
2213         isc_buffer_t b;
2214         isc_sockaddr_t *sa;
2215         const char *sep1, *sep2;
2216         isc_sockaddr_t *address = &addrinfo->sockaddr;
2217
2218         if (reason == DNS_R_LAME)
2219                 fctx->lamecount++;
2220         else {
2221                 switch (badtype) {
2222                 case badns_unreachable:
2223                         fctx->neterr++;
2224                         break;
2225                 case badns_response:
2226                         fctx->badresp++;
2227                         break;
2228                 case badns_validation:
2229                         break;  /* counted as 'valfail' */
2230                 }
2231         }
2232
2233         if (bad_server(fctx, address)) {
2234                 /*
2235                  * We already know this server is bad.
2236                  */
2237                 return;
2238         }
2239
2240         FCTXTRACE("add_bad");
2241
2242         sa = isc_mem_get(fctx->res->buckets[fctx->bucketnum].mctx,
2243                          sizeof(*sa));
2244         if (sa == NULL)
2245                 return;
2246         *sa = *address;
2247         ISC_LIST_INITANDAPPEND(fctx->bad, sa, link);
2248
2249         if (reason == DNS_R_LAME)       /* already logged */
2250                 return;
2251
2252         if (reason == DNS_R_UNEXPECTEDRCODE &&
2253             fctx->rmessage->rcode == dns_rcode_servfail &&
2254             ISFORWARDER(addrinfo))
2255                 return;
2256
2257         if (reason == DNS_R_UNEXPECTEDRCODE) {
2258                 isc_buffer_init(&b, code, sizeof(code) - 1);
2259                 dns_rcode_totext(fctx->rmessage->rcode, &b);
2260                 code[isc_buffer_usedlength(&b)] = '\0';
2261                 sep1 = "(";
2262                 sep2 = ") ";
2263         } else if (reason == DNS_R_UNEXPECTEDOPCODE) {
2264                 isc_buffer_init(&b, code, sizeof(code) - 1);
2265                 dns_opcode_totext((dns_opcode_t)fctx->rmessage->opcode, &b);
2266                 code[isc_buffer_usedlength(&b)] = '\0';
2267                 sep1 = "(";
2268                 sep2 = ") ";
2269         } else {
2270                 code[0] = '\0';
2271                 sep1 = "";
2272                 sep2 = "";
2273         }
2274         dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
2275         dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
2276         dns_rdataclass_format(fctx->res->rdclass, classbuf, sizeof(classbuf));
2277         isc_sockaddr_format(address, addrbuf, sizeof(addrbuf));
2278         isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
2279                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
2280                       "%s %s%s%sresolving '%s/%s/%s': %s",
2281                       dns_result_totext(reason), sep1, code, sep2,
2282                       namebuf, typebuf, classbuf, addrbuf);
2283 }
2284
2285 static void
2286 sort_adbfind(dns_adbfind_t *find) {
2287         dns_adbaddrinfo_t *best, *curr;
2288         dns_adbaddrinfolist_t sorted;
2289
2290         /*
2291          * Lame N^2 bubble sort.
2292          */
2293
2294         ISC_LIST_INIT(sorted);
2295         while (!ISC_LIST_EMPTY(find->list)) {
2296                 best = ISC_LIST_HEAD(find->list);
2297                 curr = ISC_LIST_NEXT(best, publink);
2298                 while (curr != NULL) {
2299                         if (curr->srtt < best->srtt)
2300                                 best = curr;
2301                         curr = ISC_LIST_NEXT(curr, publink);
2302                 }
2303                 ISC_LIST_UNLINK(find->list, best, publink);
2304                 ISC_LIST_APPEND(sorted, best, publink);
2305         }
2306         find->list = sorted;
2307 }
2308
2309 static void
2310 sort_finds(fetchctx_t *fctx) {
2311         dns_adbfind_t *best, *curr;
2312         dns_adbfindlist_t sorted;
2313         dns_adbaddrinfo_t *addrinfo, *bestaddrinfo;
2314
2315         /*
2316          * Lame N^2 bubble sort.
2317          */
2318
2319         ISC_LIST_INIT(sorted);
2320         while (!ISC_LIST_EMPTY(fctx->finds)) {
2321                 best = ISC_LIST_HEAD(fctx->finds);
2322                 bestaddrinfo = ISC_LIST_HEAD(best->list);
2323                 INSIST(bestaddrinfo != NULL);
2324                 curr = ISC_LIST_NEXT(best, publink);
2325                 while (curr != NULL) {
2326                         addrinfo = ISC_LIST_HEAD(curr->list);
2327                         INSIST(addrinfo != NULL);
2328                         if (addrinfo->srtt < bestaddrinfo->srtt) {
2329                                 best = curr;
2330                                 bestaddrinfo = addrinfo;
2331                         }
2332                         curr = ISC_LIST_NEXT(curr, publink);
2333                 }
2334                 ISC_LIST_UNLINK(fctx->finds, best, publink);
2335                 ISC_LIST_APPEND(sorted, best, publink);
2336         }
2337         fctx->finds = sorted;
2338
2339         ISC_LIST_INIT(sorted);
2340         while (!ISC_LIST_EMPTY(fctx->altfinds)) {
2341                 best = ISC_LIST_HEAD(fctx->altfinds);
2342                 bestaddrinfo = ISC_LIST_HEAD(best->list);
2343                 INSIST(bestaddrinfo != NULL);
2344                 curr = ISC_LIST_NEXT(best, publink);
2345                 while (curr != NULL) {
2346                         addrinfo = ISC_LIST_HEAD(curr->list);
2347                         INSIST(addrinfo != NULL);
2348                         if (addrinfo->srtt < bestaddrinfo->srtt) {
2349                                 best = curr;
2350                                 bestaddrinfo = addrinfo;
2351                         }
2352                         curr = ISC_LIST_NEXT(curr, publink);
2353                 }
2354                 ISC_LIST_UNLINK(fctx->altfinds, best, publink);
2355                 ISC_LIST_APPEND(sorted, best, publink);
2356         }
2357         fctx->altfinds = sorted;
2358 }
2359
2360 static void
2361 findname(fetchctx_t *fctx, dns_name_t *name, in_port_t port,
2362          unsigned int options, unsigned int flags, isc_stdtime_t now,
2363          isc_boolean_t *need_alternate)
2364 {
2365         dns_adbaddrinfo_t *ai;
2366         dns_adbfind_t *find;
2367         dns_resolver_t *res;
2368         isc_boolean_t unshared;
2369         isc_result_t result;
2370
2371         res = fctx->res;
2372         unshared = ISC_TF((fctx->options | DNS_FETCHOPT_UNSHARED) != 0);
2373         /*
2374          * If this name is a subdomain of the query domain, tell
2375          * the ADB to start looking using zone/hint data. This keeps us
2376          * from getting stuck if the nameserver is beneath the zone cut
2377          * and we don't know its address (e.g. because the A record has
2378          * expired).
2379          */
2380         if (dns_name_issubdomain(name, &fctx->domain))
2381                 options |= DNS_ADBFIND_STARTATZONE;
2382         options |= DNS_ADBFIND_GLUEOK;
2383         options |= DNS_ADBFIND_HINTOK;
2384
2385         /*
2386          * See what we know about this address.
2387          */
2388         find = NULL;
2389         result = dns_adb_createfind(fctx->adb,
2390                                     res->buckets[fctx->bucketnum].task,
2391                                     fctx_finddone, fctx, name,
2392                                     &fctx->name, fctx->type,
2393                                     options, now, NULL,
2394                                     res->view->dstport, &find);
2395         if (result != ISC_R_SUCCESS) {
2396                 if (result == DNS_R_ALIAS) {
2397                         /*
2398                          * XXXRTH  Follow the CNAME/DNAME chain?
2399                          */
2400                         dns_adb_destroyfind(&find);
2401                         fctx->adberr++;
2402                 }
2403         } else if (!ISC_LIST_EMPTY(find->list)) {
2404                 /*
2405                  * We have at least some of the addresses for the
2406                  * name.
2407                  */
2408                 INSIST((find->options & DNS_ADBFIND_WANTEVENT) == 0);
2409                 sort_adbfind(find);
2410                 if (flags != 0 || port != 0) {
2411                         for (ai = ISC_LIST_HEAD(find->list);
2412                              ai != NULL;
2413                              ai = ISC_LIST_NEXT(ai, publink)) {
2414                                 ai->flags |= flags;
2415                                 if (port != 0)
2416                                         isc_sockaddr_setport(&ai->sockaddr,
2417                                                              port);
2418                         }
2419                 }
2420                 if ((flags & FCTX_ADDRINFO_FORWARDER) != 0)
2421                         ISC_LIST_APPEND(fctx->altfinds, find, publink);
2422                 else
2423                         ISC_LIST_APPEND(fctx->finds, find, publink);
2424         } else {
2425                 /*
2426                  * We don't know any of the addresses for this
2427                  * name.
2428                  */
2429                 if ((find->options & DNS_ADBFIND_WANTEVENT) != 0) {
2430                         /*
2431                          * We're looking for them and will get an
2432                          * event about it later.
2433                          */
2434                         fctx->pending++;
2435                         /*
2436                          * Bootstrap.
2437                          */
2438                         if (need_alternate != NULL &&
2439                             !*need_alternate && unshared &&
2440                             ((res->dispatchv4 == NULL &&
2441                               find->result_v6 != DNS_R_NXDOMAIN) ||
2442                              (res->dispatchv6 == NULL &&
2443                               find->result_v4 != DNS_R_NXDOMAIN)))
2444                                 *need_alternate = ISC_TRUE;
2445                 } else {
2446                         if ((find->options & DNS_ADBFIND_LAMEPRUNED) != 0)
2447                                 fctx->lamecount++; /* cached lame server */
2448                         else
2449                                 fctx->adberr++; /* unreachable server, etc. */
2450
2451                         /*
2452                          * If we know there are no addresses for
2453                          * the family we are using then try to add
2454                          * an alternative server.
2455                          */
2456                         if (need_alternate != NULL && !*need_alternate &&
2457                             ((res->dispatchv4 == NULL &&
2458                               find->result_v6 == DNS_R_NXRRSET) ||
2459                              (res->dispatchv6 == NULL &&
2460                               find->result_v4 == DNS_R_NXRRSET)))
2461                                 *need_alternate = ISC_TRUE;
2462                         dns_adb_destroyfind(&find);
2463                 }
2464         }
2465 }
2466
2467 static isc_boolean_t
2468 isstrictsubdomain(dns_name_t *name1, dns_name_t *name2) {
2469         int order;
2470         unsigned int nlabels;
2471         dns_namereln_t namereln;
2472
2473         namereln = dns_name_fullcompare(name1, name2, &order, &nlabels);
2474         return (ISC_TF(namereln == dns_namereln_subdomain));
2475 }
2476
2477 static isc_result_t
2478 fctx_getaddresses(fetchctx_t *fctx) {
2479         dns_rdata_t rdata = DNS_RDATA_INIT;
2480         isc_result_t result;
2481         dns_resolver_t *res;
2482         isc_stdtime_t now;
2483         unsigned int stdoptions;
2484         isc_sockaddr_t *sa;
2485         dns_adbaddrinfo_t *ai;
2486         isc_boolean_t all_bad;
2487         dns_rdata_ns_t ns;
2488         isc_boolean_t need_alternate = ISC_FALSE;
2489
2490         FCTXTRACE("getaddresses");
2491
2492         /*
2493          * Don't pound on remote servers.  (Failsafe!)
2494          */
2495         fctx->restarts++;
2496         if (fctx->restarts > 10) {
2497                 FCTXTRACE("too many restarts");
2498                 return (DNS_R_SERVFAIL);
2499         }
2500
2501         res = fctx->res;
2502         stdoptions = 0;         /* Keep compiler happy. */
2503
2504         /*
2505          * Forwarders.
2506          */
2507
2508         INSIST(ISC_LIST_EMPTY(fctx->forwaddrs));
2509         INSIST(ISC_LIST_EMPTY(fctx->altaddrs));
2510
2511         /*
2512          * If this fctx has forwarders, use them; otherwise use any
2513          * selective forwarders specified in the view; otherwise use the
2514          * resolver's forwarders (if any).
2515          */
2516         sa = ISC_LIST_HEAD(fctx->forwarders);
2517         if (sa == NULL) {
2518                 dns_forwarders_t *forwarders = NULL;
2519                 dns_name_t *name = &fctx->name;
2520                 dns_name_t suffix;
2521                 unsigned int labels;
2522                 dns_fixedname_t fixed;
2523                 dns_name_t *domain;
2524
2525                 /*
2526                  * DS records are found in the parent server.
2527                  * Strip label to get the correct forwarder (if any).
2528                  */
2529                 if (dns_rdatatype_atparent(fctx->type) &&
2530                     dns_name_countlabels(name) > 1) {
2531                         dns_name_init(&suffix, NULL);
2532                         labels = dns_name_countlabels(name);
2533                         dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
2534                         name = &suffix;
2535                 }
2536
2537                 dns_fixedname_init(&fixed);
2538                 domain = dns_fixedname_name(&fixed);
2539                 result = dns_fwdtable_find2(fctx->res->view->fwdtable, name,
2540                                             domain, &forwarders);
2541                 if (result == ISC_R_SUCCESS) {
2542                         sa = ISC_LIST_HEAD(forwarders->addrs);
2543                         fctx->fwdpolicy = forwarders->fwdpolicy;
2544                         if (fctx->fwdpolicy == dns_fwdpolicy_only &&
2545                             isstrictsubdomain(domain, &fctx->domain)) {
2546                                 isc_mem_t *mctx;
2547
2548                                 mctx = res->buckets[fctx->bucketnum].mctx;
2549                                 dns_name_free(&fctx->domain, mctx);
2550                                 dns_name_init(&fctx->domain, NULL);
2551                                 result = dns_name_dup(domain, mctx,
2552                                                       &fctx->domain);
2553                                 if (result != ISC_R_SUCCESS)
2554                                         return (result);
2555                         }
2556                 }
2557         }
2558
2559         while (sa != NULL) {
2560                 if ((isc_sockaddr_pf(sa) == AF_INET &&
2561                          fctx->res->dispatchv4 == NULL) ||
2562                     (isc_sockaddr_pf(sa) == AF_INET6 &&
2563                         fctx->res->dispatchv6 == NULL)) {
2564                                 sa = ISC_LIST_NEXT(sa, link);
2565                                 continue;
2566                 }
2567                 ai = NULL;
2568                 result = dns_adb_findaddrinfo(fctx->adb,
2569                                               sa, &ai, 0);  /* XXXMLG */
2570                 if (result == ISC_R_SUCCESS) {
2571                         dns_adbaddrinfo_t *cur;
2572                         ai->flags |= FCTX_ADDRINFO_FORWARDER;
2573                         cur = ISC_LIST_HEAD(fctx->forwaddrs);
2574                         while (cur != NULL && cur->srtt < ai->srtt)
2575                                 cur = ISC_LIST_NEXT(cur, publink);
2576                         if (cur != NULL)
2577                                 ISC_LIST_INSERTBEFORE(fctx->forwaddrs, cur,
2578                                                       ai, publink);
2579                         else
2580                                 ISC_LIST_APPEND(fctx->forwaddrs, ai, publink);
2581                 }
2582                 sa = ISC_LIST_NEXT(sa, link);
2583         }
2584
2585         /*
2586          * If the forwarding policy is "only", we don't need the addresses
2587          * of the nameservers.
2588          */
2589         if (fctx->fwdpolicy == dns_fwdpolicy_only)
2590                 goto out;
2591
2592         /*
2593          * Normal nameservers.
2594          */
2595
2596         stdoptions = DNS_ADBFIND_WANTEVENT | DNS_ADBFIND_EMPTYEVENT;
2597         if (fctx->restarts == 1) {
2598                 /*
2599                  * To avoid sending out a flood of queries likely to
2600                  * result in NXRRSET, we suppress fetches for address
2601                  * families we don't have the first time through,
2602                  * provided that we have addresses in some family we
2603                  * can use.
2604                  *
2605                  * We don't want to set this option all the time, since
2606                  * if fctx->restarts > 1, we've clearly been having trouble
2607                  * with the addresses we had, so getting more could help.
2608                  */
2609                 stdoptions |= DNS_ADBFIND_AVOIDFETCHES;
2610         }
2611         if (res->dispatchv4 != NULL)
2612                 stdoptions |= DNS_ADBFIND_INET;
2613         if (res->dispatchv6 != NULL)
2614                 stdoptions |= DNS_ADBFIND_INET6;
2615         isc_stdtime_get(&now);
2616
2617         INSIST(ISC_LIST_EMPTY(fctx->finds));
2618         INSIST(ISC_LIST_EMPTY(fctx->altfinds));
2619
2620         for (result = dns_rdataset_first(&fctx->nameservers);
2621              result == ISC_R_SUCCESS;
2622              result = dns_rdataset_next(&fctx->nameservers))
2623         {
2624                 dns_rdataset_current(&fctx->nameservers, &rdata);
2625                 /*
2626                  * Extract the name from the NS record.
2627                  */
2628                 result = dns_rdata_tostruct(&rdata, &ns, NULL);
2629                 if (result != ISC_R_SUCCESS)
2630                         continue;
2631
2632                 findname(fctx, &ns.name, 0, stdoptions, 0, now,
2633                          &need_alternate);
2634                 dns_rdata_reset(&rdata);
2635                 dns_rdata_freestruct(&ns);
2636         }
2637         if (result != ISC_R_NOMORE)
2638                 return (result);
2639
2640         /*
2641          * Do we need to use 6 to 4?
2642          */
2643         if (need_alternate) {
2644                 int family;
2645                 alternate_t *a;
2646                 family = (res->dispatchv6 != NULL) ? AF_INET6 : AF_INET;
2647                 for (a = ISC_LIST_HEAD(fctx->res->alternates);
2648                      a != NULL;
2649                      a = ISC_LIST_NEXT(a, link)) {
2650                         if (!a->isaddress) {
2651                                 findname(fctx, &a->_u._n.name, a->_u._n.port,
2652                                          stdoptions, FCTX_ADDRINFO_FORWARDER,
2653                                          now, NULL);
2654                                 continue;
2655                         }
2656                         if (isc_sockaddr_pf(&a->_u.addr) != family)
2657                                 continue;
2658                         ai = NULL;
2659                         result = dns_adb_findaddrinfo(fctx->adb, &a->_u.addr,
2660                                                       &ai, 0);
2661                         if (result == ISC_R_SUCCESS) {
2662                                 dns_adbaddrinfo_t *cur;
2663                                 ai->flags |= FCTX_ADDRINFO_FORWARDER;
2664                                 cur = ISC_LIST_HEAD(fctx->altaddrs);
2665                                 while (cur != NULL && cur->srtt < ai->srtt)
2666                                         cur = ISC_LIST_NEXT(cur, publink);
2667                                 if (cur != NULL)
2668                                         ISC_LIST_INSERTBEFORE(fctx->altaddrs,
2669                                                               cur, ai, publink);
2670                                 else
2671                                         ISC_LIST_APPEND(fctx->altaddrs, ai,
2672                                                         publink);
2673                         }
2674                 }
2675         }
2676
2677  out:
2678         /*
2679          * Mark all known bad servers.
2680          */
2681         all_bad = mark_bad(fctx);
2682
2683         /*
2684          * How are we doing?
2685          */
2686         if (all_bad) {
2687                 /*
2688                  * We've got no addresses.
2689                  */
2690                 if (fctx->pending > 0) {
2691                         /*
2692                          * We're fetching the addresses, but don't have any
2693                          * yet.   Tell the caller to wait for an answer.
2694                          */
2695                         result = DNS_R_WAIT;
2696                 } else {
2697                         /*
2698                          * We've lost completely.  We don't know any
2699                          * addresses, and the ADB has told us it can't get
2700                          * them.
2701                          */
2702                         FCTXTRACE("no addresses");
2703                         result = ISC_R_FAILURE;
2704                 }
2705         } else {
2706                 /*
2707                  * We've found some addresses.  We might still be looking
2708                  * for more addresses.
2709                  */
2710                 sort_finds(fctx);
2711                 result = ISC_R_SUCCESS;
2712         }
2713
2714         return (result);
2715 }
2716
2717 static inline void
2718 possibly_mark(fetchctx_t *fctx, dns_adbaddrinfo_t *addr)
2719 {
2720         isc_netaddr_t na;
2721         char buf[ISC_NETADDR_FORMATSIZE];
2722         isc_sockaddr_t *sa;
2723         isc_boolean_t aborted = ISC_FALSE;
2724         isc_boolean_t bogus;
2725         dns_acl_t *blackhole;
2726         isc_netaddr_t ipaddr;
2727         dns_peer_t *peer = NULL;
2728         dns_resolver_t *res;
2729         const char *msg = NULL;
2730
2731         sa = &addr->sockaddr;
2732
2733         res = fctx->res;
2734         isc_netaddr_fromsockaddr(&ipaddr, sa);
2735         blackhole = dns_dispatchmgr_getblackhole(res->dispatchmgr);
2736         (void) dns_peerlist_peerbyaddr(res->view->peers, &ipaddr, &peer);
2737
2738         if (blackhole != NULL) {
2739                 int match;
2740
2741                 if (dns_acl_match(&ipaddr, NULL, blackhole,
2742                                   &res->view->aclenv,
2743                                   &match, NULL) == ISC_R_SUCCESS &&
2744                     match > 0)
2745                         aborted = ISC_TRUE;
2746         }
2747
2748         if (peer != NULL &&
2749             dns_peer_getbogus(peer, &bogus) == ISC_R_SUCCESS &&
2750             bogus)
2751                 aborted = ISC_TRUE;
2752
2753         if (aborted) {
2754                 addr->flags |= FCTX_ADDRINFO_MARK;
2755                 msg = "ignoring blackholed / bogus server: ";
2756         } else if (isc_sockaddr_ismulticast(sa)) {
2757                 addr->flags |= FCTX_ADDRINFO_MARK;
2758                 msg = "ignoring multicast address: ";
2759         } else if (isc_sockaddr_isexperimental(sa)) {
2760                 addr->flags |= FCTX_ADDRINFO_MARK;
2761                 msg = "ignoring experimental address: ";
2762         } else if (sa->type.sa.sa_family != AF_INET6) {
2763                 return;
2764         } else if (IN6_IS_ADDR_V4MAPPED(&sa->type.sin6.sin6_addr)) {
2765                 addr->flags |= FCTX_ADDRINFO_MARK;
2766                 msg = "ignoring IPv6 mapped IPV4 address: ";
2767         } else if (IN6_IS_ADDR_V4COMPAT(&sa->type.sin6.sin6_addr)) {
2768                 addr->flags |= FCTX_ADDRINFO_MARK;
2769                 msg = "ignoring IPv6 compatibility IPV4 address: ";
2770         } else
2771                 return;
2772
2773         if (!isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(3)))
2774                 return;
2775
2776         isc_netaddr_fromsockaddr(&na, sa);
2777         isc_netaddr_format(&na, buf, sizeof(buf));
2778         FCTXTRACE2(msg, buf);
2779 }
2780
2781 static inline dns_adbaddrinfo_t *
2782 fctx_nextaddress(fetchctx_t *fctx) {
2783         dns_adbfind_t *find, *start;
2784         dns_adbaddrinfo_t *addrinfo;
2785         dns_adbaddrinfo_t *faddrinfo;
2786
2787         /*
2788          * Return the next untried address, if any.
2789          */
2790
2791         /*
2792          * Find the first unmarked forwarder (if any).
2793          */
2794         for (addrinfo = ISC_LIST_HEAD(fctx->forwaddrs);
2795              addrinfo != NULL;
2796              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2797                 if (!UNMARKED(addrinfo))
2798                         continue;
2799                 possibly_mark(fctx, addrinfo);
2800                 if (UNMARKED(addrinfo)) {
2801                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2802                         fctx->find = NULL;
2803                         return (addrinfo);
2804                 }
2805         }
2806
2807         /*
2808          * No forwarders.  Move to the next find.
2809          */
2810
2811         fctx->attributes |= FCTX_ATTR_TRIEDFIND;
2812
2813         find = fctx->find;
2814         if (find == NULL)
2815                 find = ISC_LIST_HEAD(fctx->finds);
2816         else {
2817                 find = ISC_LIST_NEXT(find, publink);
2818                 if (find == NULL)
2819                         find = ISC_LIST_HEAD(fctx->finds);
2820         }
2821
2822         /*
2823          * Find the first unmarked addrinfo.
2824          */
2825         addrinfo = NULL;
2826         if (find != NULL) {
2827                 start = find;
2828                 do {
2829                         for (addrinfo = ISC_LIST_HEAD(find->list);
2830                              addrinfo != NULL;
2831                              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2832                                 if (!UNMARKED(addrinfo))
2833                                         continue;
2834                                 possibly_mark(fctx, addrinfo);
2835                                 if (UNMARKED(addrinfo)) {
2836                                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2837                                         break;
2838                                 }
2839                         }
2840                         if (addrinfo != NULL)
2841                                 break;
2842                         find = ISC_LIST_NEXT(find, publink);
2843                         if (find == NULL)
2844                                 find = ISC_LIST_HEAD(fctx->finds);
2845                 } while (find != start);
2846         }
2847
2848         fctx->find = find;
2849         if (addrinfo != NULL)
2850                 return (addrinfo);
2851
2852         /*
2853          * No nameservers left.  Try alternates.
2854          */
2855
2856         fctx->attributes |= FCTX_ATTR_TRIEDALT;
2857
2858         find = fctx->altfind;
2859         if (find == NULL)
2860                 find = ISC_LIST_HEAD(fctx->altfinds);
2861         else {
2862                 find = ISC_LIST_NEXT(find, publink);
2863                 if (find == NULL)
2864                         find = ISC_LIST_HEAD(fctx->altfinds);
2865         }
2866
2867         /*
2868          * Find the first unmarked addrinfo.
2869          */
2870         addrinfo = NULL;
2871         if (find != NULL) {
2872                 start = find;
2873                 do {
2874                         for (addrinfo = ISC_LIST_HEAD(find->list);
2875                              addrinfo != NULL;
2876                              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2877                                 if (!UNMARKED(addrinfo))
2878                                         continue;
2879                                 possibly_mark(fctx, addrinfo);
2880                                 if (UNMARKED(addrinfo)) {
2881                                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2882                                         break;
2883                                 }
2884                         }
2885                         if (addrinfo != NULL)
2886                                 break;
2887                         find = ISC_LIST_NEXT(find, publink);
2888                         if (find == NULL)
2889                                 find = ISC_LIST_HEAD(fctx->altfinds);
2890                 } while (find != start);
2891         }
2892
2893         faddrinfo = addrinfo;
2894
2895         /*
2896          * See if we have a better alternate server by address.
2897          */
2898
2899         for (addrinfo = ISC_LIST_HEAD(fctx->altaddrs);
2900              addrinfo != NULL;
2901              addrinfo = ISC_LIST_NEXT(addrinfo, publink)) {
2902                 if (!UNMARKED(addrinfo))
2903                         continue;
2904                 possibly_mark(fctx, addrinfo);
2905                 if (UNMARKED(addrinfo) &&
2906                     (faddrinfo == NULL ||
2907                      addrinfo->srtt < faddrinfo->srtt)) {
2908                         if (faddrinfo != NULL)
2909                                 faddrinfo->flags &= ~FCTX_ADDRINFO_MARK;
2910                         addrinfo->flags |= FCTX_ADDRINFO_MARK;
2911                         break;
2912                 }
2913         }
2914
2915         if (addrinfo == NULL) {
2916                 addrinfo = faddrinfo;
2917                 fctx->altfind = find;
2918         }
2919
2920         return (addrinfo);
2921 }
2922
2923 static void
2924 fctx_try(fetchctx_t *fctx, isc_boolean_t retrying) {
2925         isc_result_t result;
2926         dns_adbaddrinfo_t *addrinfo;
2927
2928         FCTXTRACE("try");
2929
2930         REQUIRE(!ADDRWAIT(fctx));
2931
2932         addrinfo = fctx_nextaddress(fctx);
2933         if (addrinfo == NULL) {
2934                 /*
2935                  * We have no more addresses.  Start over.
2936                  */
2937                 fctx_cancelqueries(fctx, ISC_TRUE);
2938                 fctx_cleanupfinds(fctx);
2939                 fctx_cleanupaltfinds(fctx);
2940                 fctx_cleanupforwaddrs(fctx);
2941                 fctx_cleanupaltaddrs(fctx);
2942                 result = fctx_getaddresses(fctx);
2943                 if (result == DNS_R_WAIT) {
2944                         /*
2945                          * Sleep waiting for addresses.
2946                          */
2947                         FCTXTRACE("addrwait");
2948                         fctx->attributes |= FCTX_ATTR_ADDRWAIT;
2949                         return;
2950                 } else if (result != ISC_R_SUCCESS) {
2951                         /*
2952                          * Something bad happened.
2953                          */
2954                         fctx_done(fctx, result, __LINE__);
2955                         return;
2956                 }
2957
2958                 addrinfo = fctx_nextaddress(fctx);
2959                 /*
2960                  * While we may have addresses from the ADB, they
2961                  * might be bad ones.  In this case, return SERVFAIL.
2962                  */
2963                 if (addrinfo == NULL) {
2964                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
2965                         return;
2966                 }
2967         }
2968
2969         result = fctx_query(fctx, addrinfo, fctx->options);
2970         if (result != ISC_R_SUCCESS)
2971                 fctx_done(fctx, result, __LINE__);
2972         else if (retrying)
2973                 inc_stats(fctx->res, dns_resstatscounter_retry);
2974 }
2975
2976 static isc_boolean_t
2977 fctx_destroy(fetchctx_t *fctx) {
2978         dns_resolver_t *res;
2979         unsigned int bucketnum;
2980         isc_sockaddr_t *sa, *next_sa;
2981
2982         /*
2983          * Caller must be holding the bucket lock.
2984          */
2985
2986         REQUIRE(VALID_FCTX(fctx));
2987         REQUIRE(fctx->state == fetchstate_done ||
2988                 fctx->state == fetchstate_init);
2989         REQUIRE(ISC_LIST_EMPTY(fctx->events));
2990         REQUIRE(ISC_LIST_EMPTY(fctx->queries));
2991         REQUIRE(ISC_LIST_EMPTY(fctx->finds));
2992         REQUIRE(ISC_LIST_EMPTY(fctx->altfinds));
2993         REQUIRE(fctx->pending == 0);
2994         REQUIRE(fctx->references == 0);
2995         REQUIRE(ISC_LIST_EMPTY(fctx->validators));
2996
2997         FCTXTRACE("destroy");
2998
2999         res = fctx->res;
3000         bucketnum = fctx->bucketnum;
3001
3002         ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
3003
3004         /*
3005          * Free bad.
3006          */
3007         for (sa = ISC_LIST_HEAD(fctx->bad);
3008              sa != NULL;
3009              sa = next_sa) {
3010                 next_sa = ISC_LIST_NEXT(sa, link);
3011                 ISC_LIST_UNLINK(fctx->bad, sa, link);
3012                 isc_mem_put(res->buckets[bucketnum].mctx, sa, sizeof(*sa));
3013         }
3014
3015         for (sa = ISC_LIST_HEAD(fctx->edns);
3016              sa != NULL;
3017              sa = next_sa) {
3018                 next_sa = ISC_LIST_NEXT(sa, link);
3019                 ISC_LIST_UNLINK(fctx->edns, sa, link);
3020                 isc_mem_put(res->buckets[bucketnum].mctx, sa, sizeof(*sa));
3021         }
3022
3023         for (sa = ISC_LIST_HEAD(fctx->edns512);
3024              sa != NULL;
3025              sa = next_sa) {
3026                 next_sa = ISC_LIST_NEXT(sa, link);
3027                 ISC_LIST_UNLINK(fctx->edns512, sa, link);
3028                 isc_mem_put(res->buckets[bucketnum].mctx, sa, sizeof(*sa));
3029         }
3030
3031         isc_timer_detach(&fctx->timer);
3032         dns_message_destroy(&fctx->rmessage);
3033         dns_message_destroy(&fctx->qmessage);
3034         if (dns_name_countlabels(&fctx->domain) > 0)
3035                 dns_name_free(&fctx->domain, res->buckets[bucketnum].mctx);
3036         if (dns_rdataset_isassociated(&fctx->nameservers))
3037                 dns_rdataset_disassociate(&fctx->nameservers);
3038         dns_name_free(&fctx->name, res->buckets[bucketnum].mctx);
3039         dns_db_detach(&fctx->cache);
3040         dns_adb_detach(&fctx->adb);
3041         isc_mem_free(res->buckets[bucketnum].mctx, fctx->info);
3042         isc_mem_put(res->buckets[bucketnum].mctx, fctx, sizeof(*fctx));
3043
3044         LOCK(&res->nlock);
3045         res->nfctx--;
3046         UNLOCK(&res->nlock);
3047
3048         if (res->buckets[bucketnum].exiting &&
3049             ISC_LIST_EMPTY(res->buckets[bucketnum].fctxs))
3050                 return (ISC_TRUE);
3051
3052         return (ISC_FALSE);
3053 }
3054
3055 /*
3056  * Fetch event handlers.
3057  */
3058
3059 static void
3060 fctx_timeout(isc_task_t *task, isc_event_t *event) {
3061         fetchctx_t *fctx = event->ev_arg;
3062         isc_timerevent_t *tevent = (isc_timerevent_t *)event;
3063         resquery_t *query;
3064
3065         REQUIRE(VALID_FCTX(fctx));
3066
3067         UNUSED(task);
3068
3069         FCTXTRACE("timeout");
3070
3071         inc_stats(fctx->res, dns_resstatscounter_querytimeout);
3072
3073         if (event->ev_type == ISC_TIMEREVENT_LIFE) {
3074                 fctx->reason = NULL;
3075                 fctx_done(fctx, ISC_R_TIMEDOUT, __LINE__);
3076         } else {
3077                 isc_result_t result;
3078
3079                 fctx->timeouts++;
3080                 fctx->timeout = ISC_TRUE;
3081                 /*
3082                  * We could cancel the running queries here, or we could let
3083                  * them keep going.  Since we normally use separate sockets for
3084                  * different queries, we adopt the former approach to reduce
3085                  * the number of open sockets: cancel the oldest query if it
3086                  * expired after the query had started (this is usually the
3087                  * case but is not always so, depending on the task schedule
3088                  * timing).
3089                  */
3090                 query = ISC_LIST_HEAD(fctx->queries);
3091                 if (query != NULL &&
3092                     isc_time_compare(&tevent->due, &query->start) >= 0) {
3093                         fctx_cancelquery(&query, NULL, NULL, ISC_TRUE);
3094                 }
3095                 fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
3096                 /*
3097                  * Our timer has triggered.  Reestablish the fctx lifetime
3098                  * timer.
3099                  */
3100                 result = fctx_starttimer(fctx);
3101                 if (result != ISC_R_SUCCESS)
3102                         fctx_done(fctx, result, __LINE__);
3103                 else
3104                         /*
3105                          * Keep trying.
3106                          */
3107                         fctx_try(fctx, ISC_TRUE);
3108         }
3109
3110         isc_event_free(&event);
3111 }
3112
3113 static void
3114 fctx_shutdown(fetchctx_t *fctx) {
3115         isc_event_t *cevent;
3116
3117         /*
3118          * Start the shutdown process for fctx, if it isn't already underway.
3119          */
3120
3121         FCTXTRACE("shutdown");
3122
3123         /*
3124          * The caller must be holding the appropriate bucket lock.
3125          */
3126
3127         if (fctx->want_shutdown)
3128                 return;
3129
3130         fctx->want_shutdown = ISC_TRUE;
3131
3132         /*
3133          * Unless we're still initializing (in which case the
3134          * control event is still outstanding), we need to post
3135          * the control event to tell the fetch we want it to
3136          * exit.
3137          */
3138         if (fctx->state != fetchstate_init) {
3139                 cevent = &fctx->control_event;
3140                 isc_task_send(fctx->res->buckets[fctx->bucketnum].task,
3141                               &cevent);
3142         }
3143 }
3144
3145 static void
3146 fctx_doshutdown(isc_task_t *task, isc_event_t *event) {
3147         fetchctx_t *fctx = event->ev_arg;
3148         isc_boolean_t bucket_empty = ISC_FALSE;
3149         dns_resolver_t *res;
3150         unsigned int bucketnum;
3151         dns_validator_t *validator;
3152
3153         REQUIRE(VALID_FCTX(fctx));
3154
3155         UNUSED(task);
3156
3157         res = fctx->res;
3158         bucketnum = fctx->bucketnum;
3159
3160         FCTXTRACE("doshutdown");
3161
3162         /*
3163          * An fctx that is shutting down is no longer in ADDRWAIT mode.
3164          */
3165         fctx->attributes &= ~FCTX_ATTR_ADDRWAIT;
3166
3167         /*
3168          * Cancel all pending validators.  Note that this must be done
3169          * without the bucket lock held, since that could cause deadlock.
3170          */
3171         validator = ISC_LIST_HEAD(fctx->validators);
3172         while (validator != NULL) {
3173                 dns_validator_cancel(validator);
3174                 validator = ISC_LIST_NEXT(validator, link);
3175         }
3176
3177         if (fctx->nsfetch != NULL)
3178                 dns_resolver_cancelfetch(fctx->nsfetch);
3179
3180         /*
3181          * Shut down anything that is still running on behalf of this
3182          * fetch.  To avoid deadlock with the ADB, we must do this
3183          * before we lock the bucket lock.
3184          */
3185         fctx_stopeverything(fctx, ISC_FALSE);
3186
3187         LOCK(&res->buckets[bucketnum].lock);
3188
3189         fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
3190
3191         INSIST(fctx->state == fetchstate_active ||
3192                fctx->state == fetchstate_done);
3193         INSIST(fctx->want_shutdown);
3194
3195         if (fctx->state != fetchstate_done) {
3196                 fctx->state = fetchstate_done;
3197                 fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
3198         }
3199
3200         if (fctx->references == 0 && fctx->pending == 0 &&
3201             fctx->nqueries == 0 && ISC_LIST_EMPTY(fctx->validators))
3202                 bucket_empty = fctx_destroy(fctx);
3203
3204         UNLOCK(&res->buckets[bucketnum].lock);
3205
3206         if (bucket_empty)
3207                 empty_bucket(res);
3208 }
3209
3210 static void
3211 fctx_start(isc_task_t *task, isc_event_t *event) {
3212         fetchctx_t *fctx = event->ev_arg;
3213         isc_boolean_t done = ISC_FALSE, bucket_empty = ISC_FALSE;
3214         dns_resolver_t *res;
3215         unsigned int bucketnum;
3216
3217         REQUIRE(VALID_FCTX(fctx));
3218
3219         UNUSED(task);
3220
3221         res = fctx->res;
3222         bucketnum = fctx->bucketnum;
3223
3224         FCTXTRACE("start");
3225
3226         LOCK(&res->buckets[bucketnum].lock);
3227
3228         INSIST(fctx->state == fetchstate_init);
3229         if (fctx->want_shutdown) {
3230                 /*
3231                  * We haven't started this fctx yet, and we've been requested
3232                  * to shut it down.
3233                  */
3234                 fctx->attributes |= FCTX_ATTR_SHUTTINGDOWN;
3235                 fctx->state = fetchstate_done;
3236                 fctx_sendevents(fctx, ISC_R_CANCELED, __LINE__);
3237                 /*
3238                  * Since we haven't started, we INSIST that we have no
3239                  * pending ADB finds and no pending validations.
3240                  */
3241                 INSIST(fctx->pending == 0);
3242                 INSIST(fctx->nqueries == 0);
3243                 INSIST(ISC_LIST_EMPTY(fctx->validators));
3244                 if (fctx->references == 0) {
3245                         /*
3246                          * It's now safe to destroy this fctx.
3247                          */
3248                         bucket_empty = fctx_destroy(fctx);
3249                 }
3250                 done = ISC_TRUE;
3251         } else {
3252                 /*
3253                  * Normal fctx startup.
3254                  */
3255                 fctx->state = fetchstate_active;
3256                 /*
3257                  * Reset the control event for later use in shutting down
3258                  * the fctx.
3259                  */
3260                 ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
3261                                DNS_EVENT_FETCHCONTROL, fctx_doshutdown, fctx,
3262                                NULL, NULL, NULL);
3263         }
3264
3265         UNLOCK(&res->buckets[bucketnum].lock);
3266
3267         if (!done) {
3268                 isc_result_t result;
3269
3270                 /*
3271                  * All is well.  Start working on the fetch.
3272                  */
3273                 result = fctx_starttimer(fctx);
3274                 if (result != ISC_R_SUCCESS)
3275                         fctx_done(fctx, result, __LINE__);
3276                 else
3277                         fctx_try(fctx, ISC_FALSE);
3278         } else if (bucket_empty)
3279                 empty_bucket(res);
3280 }
3281
3282 /*
3283  * Fetch Creation, Joining, and Cancelation.
3284  */
3285
3286 static inline isc_result_t
3287 fctx_join(fetchctx_t *fctx, isc_task_t *task, isc_sockaddr_t *client,
3288           dns_messageid_t id, isc_taskaction_t action, void *arg,
3289           dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
3290           dns_fetch_t *fetch)
3291 {
3292         isc_task_t *clone;
3293         dns_fetchevent_t *event;
3294
3295         FCTXTRACE("join");
3296
3297         /*
3298          * We store the task we're going to send this event to in the
3299          * sender field.  We'll make the fetch the sender when we actually
3300          * send the event.
3301          */
3302         clone = NULL;
3303         isc_task_attach(task, &clone);
3304         event = (dns_fetchevent_t *)
3305                 isc_event_allocate(fctx->res->mctx, clone, DNS_EVENT_FETCHDONE,
3306                                    action, arg, sizeof(*event));
3307         if (event == NULL) {
3308                 isc_task_detach(&clone);
3309                 return (ISC_R_NOMEMORY);
3310         }
3311         event->result = DNS_R_SERVFAIL;
3312         event->qtype = fctx->type;
3313         event->db = NULL;
3314         event->node = NULL;
3315         event->rdataset = rdataset;
3316         event->sigrdataset = sigrdataset;
3317         event->fetch = fetch;
3318         event->client = client;
3319         event->id = id;
3320         dns_fixedname_init(&event->foundname);
3321
3322         /*
3323          * Make sure that we can store the sigrdataset in the
3324          * first event if it is needed by any of the events.
3325          */
3326         if (event->sigrdataset != NULL)
3327                 ISC_LIST_PREPEND(fctx->events, event, ev_link);
3328         else
3329                 ISC_LIST_APPEND(fctx->events, event, ev_link);
3330         fctx->references++;
3331
3332         fetch->magic = DNS_FETCH_MAGIC;
3333         fetch->private = fctx;
3334
3335         return (ISC_R_SUCCESS);
3336 }
3337
3338 static isc_result_t
3339 fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
3340             dns_name_t *domain, dns_rdataset_t *nameservers,
3341             unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp)
3342 {
3343         fetchctx_t *fctx;
3344         isc_result_t result;
3345         isc_result_t iresult;
3346         isc_interval_t interval;
3347         dns_fixedname_t fixed;
3348         unsigned int findoptions = 0;
3349         char buf[DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE];
3350         char typebuf[DNS_RDATATYPE_FORMATSIZE];
3351         dns_name_t suffix;
3352
3353         /*
3354          * Caller must be holding the lock for bucket number 'bucketnum'.
3355          */
3356         REQUIRE(fctxp != NULL && *fctxp == NULL);
3357
3358         fctx = isc_mem_get(res->buckets[bucketnum].mctx, sizeof(*fctx));
3359         if (fctx == NULL)
3360                 return (ISC_R_NOMEMORY);
3361         dns_name_format(name, buf, sizeof(buf));
3362         dns_rdatatype_format(type, typebuf, sizeof(typebuf));
3363         strcat(buf, "/");       /* checked */
3364         strcat(buf, typebuf);   /* checked */
3365         fctx->info = isc_mem_strdup(res->buckets[bucketnum].mctx, buf);
3366         if (fctx->info == NULL) {
3367                 result = ISC_R_NOMEMORY;
3368                 goto cleanup_fetch;
3369         }
3370         FCTXTRACE("create");
3371         dns_name_init(&fctx->name, NULL);
3372         result = dns_name_dup(name, res->buckets[bucketnum].mctx, &fctx->name);
3373         if (result != ISC_R_SUCCESS)
3374                 goto cleanup_info;
3375         dns_name_init(&fctx->domain, NULL);
3376         dns_rdataset_init(&fctx->nameservers);
3377
3378         fctx->type = type;
3379         fctx->options = options;
3380         /*
3381          * Note!  We do not attach to the task.  We are relying on the
3382          * resolver to ensure that this task doesn't go away while we are
3383          * using it.
3384          */
3385         fctx->res = res;
3386         fctx->references = 0;
3387         fctx->bucketnum = bucketnum;
3388         fctx->state = fetchstate_init;
3389         fctx->want_shutdown = ISC_FALSE;
3390         fctx->cloned = ISC_FALSE;
3391         ISC_LIST_INIT(fctx->queries);
3392         ISC_LIST_INIT(fctx->finds);
3393         ISC_LIST_INIT(fctx->altfinds);
3394         ISC_LIST_INIT(fctx->forwaddrs);
3395         ISC_LIST_INIT(fctx->altaddrs);
3396         ISC_LIST_INIT(fctx->forwarders);
3397         fctx->fwdpolicy = dns_fwdpolicy_none;
3398         ISC_LIST_INIT(fctx->bad);
3399         ISC_LIST_INIT(fctx->edns);
3400         ISC_LIST_INIT(fctx->edns512);
3401         ISC_LIST_INIT(fctx->validators);
3402         fctx->validator = NULL;
3403         fctx->find = NULL;
3404         fctx->altfind = NULL;
3405         fctx->pending = 0;
3406         fctx->restarts = 0;
3407         fctx->querysent = 0;
3408         fctx->referrals = 0;
3409         TIME_NOW(&fctx->start);
3410         fctx->timeouts = 0;
3411         fctx->lamecount = 0;
3412         fctx->adberr = 0;
3413         fctx->neterr = 0;
3414         fctx->badresp = 0;
3415         fctx->findfail = 0;
3416         fctx->valfail = 0;
3417         fctx->result = ISC_R_FAILURE;
3418         fctx->vresult = ISC_R_SUCCESS;
3419         fctx->exitline = -1;    /* sentinel */
3420         fctx->logged = ISC_FALSE;
3421         fctx->attributes = 0;
3422         fctx->spilled = ISC_FALSE;
3423         fctx->nqueries = 0;
3424         fctx->reason = NULL;
3425         fctx->timeout = ISC_FALSE;
3426
3427         dns_name_init(&fctx->nsname, NULL);
3428         fctx->nsfetch = NULL;
3429         dns_rdataset_init(&fctx->nsrrset);
3430
3431         if (domain == NULL) {
3432                 dns_forwarders_t *forwarders = NULL;
3433                 unsigned int labels;
3434                 dns_name_t *fwdname = name;
3435
3436                 /*
3437                  * DS records are found in the parent server.
3438                  * Strip label to get the correct forwarder (if any).
3439                  */
3440                 if (dns_rdatatype_atparent(fctx->type) &&
3441                     dns_name_countlabels(name) > 1) {
3442                         dns_name_init(&suffix, NULL);
3443                         labels = dns_name_countlabels(name);
3444                         dns_name_getlabelsequence(name, 1, labels - 1, &suffix);
3445                         fwdname = &suffix;
3446                 }
3447                 dns_fixedname_init(&fixed);
3448                 domain = dns_fixedname_name(&fixed);
3449                 result = dns_fwdtable_find2(fctx->res->view->fwdtable, fwdname,
3450                                             domain, &forwarders);
3451                 if (result == ISC_R_SUCCESS)
3452                         fctx->fwdpolicy = forwarders->fwdpolicy;
3453
3454                 if (fctx->fwdpolicy != dns_fwdpolicy_only) {
3455                         /*
3456                          * The caller didn't supply a query domain and
3457                          * nameservers, and we're not in forward-only mode,
3458                          * so find the best nameservers to use.
3459                          */
3460                         if (dns_rdatatype_atparent(fctx->type))
3461                                 findoptions |= DNS_DBFIND_NOEXACT;
3462                         result = dns_view_findzonecut(res->view, name, domain,
3463                                                       0, findoptions, ISC_TRUE,
3464                                                       &fctx->nameservers,
3465                                                       NULL);
3466                         if (result != ISC_R_SUCCESS)
3467                                 goto cleanup_name;
3468                         result = dns_name_dup(domain,
3469                                               res->buckets[bucketnum].mctx,
3470                                               &fctx->domain);
3471                         if (result != ISC_R_SUCCESS) {
3472                                 dns_rdataset_disassociate(&fctx->nameservers);
3473                                 goto cleanup_name;
3474                         }
3475                 } else {
3476                         /*
3477                          * We're in forward-only mode.  Set the query domain.
3478                          */
3479                         result = dns_name_dup(domain,
3480                                               res->buckets[bucketnum].mctx,
3481                                               &fctx->domain);
3482                         if (result != ISC_R_SUCCESS)
3483                                 goto cleanup_name;
3484                 }
3485         } else {
3486                 result = dns_name_dup(domain,
3487                                       res->buckets[bucketnum].mctx,
3488                                       &fctx->domain);
3489                 if (result != ISC_R_SUCCESS)
3490                         goto cleanup_name;
3491                 dns_rdataset_clone(nameservers, &fctx->nameservers);
3492         }
3493
3494         INSIST(dns_name_issubdomain(&fctx->name, &fctx->domain));
3495
3496         fctx->qmessage = NULL;
3497         result = dns_message_create(res->buckets[bucketnum].mctx,
3498                                     DNS_MESSAGE_INTENTRENDER,
3499                                     &fctx->qmessage);
3500
3501         if (result != ISC_R_SUCCESS)
3502                 goto cleanup_domain;
3503
3504         fctx->rmessage = NULL;
3505         result = dns_message_create(res->buckets[bucketnum].mctx,
3506                                     DNS_MESSAGE_INTENTPARSE,
3507                                     &fctx->rmessage);
3508
3509         if (result != ISC_R_SUCCESS)
3510                 goto cleanup_qmessage;
3511
3512         /*
3513          * Compute an expiration time for the entire fetch.
3514          */
3515         isc_interval_set(&interval, 30, 0);             /* XXXRTH constant */
3516         iresult = isc_time_nowplusinterval(&fctx->expires, &interval);
3517         if (iresult != ISC_R_SUCCESS) {
3518                 UNEXPECTED_ERROR(__FILE__, __LINE__,
3519                                  "isc_time_nowplusinterval: %s",
3520                                  isc_result_totext(iresult));
3521                 result = ISC_R_UNEXPECTED;
3522                 goto cleanup_rmessage;
3523         }
3524
3525         /*
3526          * Default retry interval initialization.  We set the interval now
3527          * mostly so it won't be uninitialized.  It will be set to the
3528          * correct value before a query is issued.
3529          */
3530         isc_interval_set(&fctx->interval, 2, 0);
3531
3532         /*
3533          * Create an inactive timer.  It will be made active when the fetch
3534          * is actually started.
3535          */
3536         fctx->timer = NULL;
3537         iresult = isc_timer_create(res->timermgr, isc_timertype_inactive,
3538                                    NULL, NULL,
3539                                    res->buckets[bucketnum].task, fctx_timeout,
3540                                    fctx, &fctx->timer);
3541         if (iresult != ISC_R_SUCCESS) {
3542                 UNEXPECTED_ERROR(__FILE__, __LINE__,
3543                                  "isc_timer_create: %s",
3544                                  isc_result_totext(iresult));
3545                 result = ISC_R_UNEXPECTED;
3546                 goto cleanup_rmessage;
3547         }
3548
3549         /*
3550          * Attach to the view's cache and adb.
3551          */
3552         fctx->cache = NULL;
3553         dns_db_attach(res->view->cachedb, &fctx->cache);
3554         fctx->adb = NULL;
3555         dns_adb_attach(res->view->adb, &fctx->adb);
3556
3557         ISC_LIST_INIT(fctx->events);
3558         ISC_LINK_INIT(fctx, link);
3559         fctx->magic = FCTX_MAGIC;
3560
3561         ISC_LIST_APPEND(res->buckets[bucketnum].fctxs, fctx, link);
3562
3563         LOCK(&res->nlock);
3564         res->nfctx++;
3565         UNLOCK(&res->nlock);
3566
3567         *fctxp = fctx;
3568
3569         return (ISC_R_SUCCESS);
3570
3571  cleanup_rmessage:
3572         dns_message_destroy(&fctx->rmessage);
3573
3574  cleanup_qmessage:
3575         dns_message_destroy(&fctx->qmessage);
3576
3577  cleanup_domain:
3578         if (dns_name_countlabels(&fctx->domain) > 0)
3579                 dns_name_free(&fctx->domain, res->buckets[bucketnum].mctx);
3580         if (dns_rdataset_isassociated(&fctx->nameservers))
3581                 dns_rdataset_disassociate(&fctx->nameservers);
3582
3583  cleanup_name:
3584         dns_name_free(&fctx->name, res->buckets[bucketnum].mctx);
3585
3586  cleanup_info:
3587         isc_mem_free(res->buckets[bucketnum].mctx, fctx->info);
3588
3589  cleanup_fetch:
3590         isc_mem_put(res->buckets[bucketnum].mctx, fctx, sizeof(*fctx));
3591
3592         return (result);
3593 }
3594
3595 /*
3596  * Handle Responses
3597  */
3598 static inline isc_boolean_t
3599 is_lame(fetchctx_t *fctx) {
3600         dns_message_t *message = fctx->rmessage;
3601         dns_name_t *name;
3602         dns_rdataset_t *rdataset;
3603         isc_result_t result;
3604
3605         if (message->rcode != dns_rcode_noerror &&
3606             message->rcode != dns_rcode_nxdomain)
3607                 return (ISC_FALSE);
3608
3609         if (message->counts[DNS_SECTION_ANSWER] != 0)
3610                 return (ISC_FALSE);
3611
3612         if (message->counts[DNS_SECTION_AUTHORITY] == 0)
3613                 return (ISC_FALSE);
3614
3615         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
3616         while (result == ISC_R_SUCCESS) {
3617                 name = NULL;
3618                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
3619                 for (rdataset = ISC_LIST_HEAD(name->list);
3620                      rdataset != NULL;
3621                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
3622                         dns_namereln_t namereln;
3623                         int order;
3624                         unsigned int labels;
3625                         if (rdataset->type != dns_rdatatype_ns)
3626                                 continue;
3627                         namereln = dns_name_fullcompare(name, &fctx->domain,
3628                                                         &order, &labels);
3629                         if (namereln == dns_namereln_equal &&
3630                             (message->flags & DNS_MESSAGEFLAG_AA) != 0)
3631                                 return (ISC_FALSE);
3632                         if (namereln == dns_namereln_subdomain)
3633                                 return (ISC_FALSE);
3634                         return (ISC_TRUE);
3635                 }
3636                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
3637         }
3638
3639         return (ISC_FALSE);
3640 }
3641
3642 static inline void
3643 log_lame(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo) {
3644         char namebuf[DNS_NAME_FORMATSIZE];
3645         char domainbuf[DNS_NAME_FORMATSIZE];
3646         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
3647
3648         dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
3649         dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
3650         isc_sockaddr_format(&addrinfo->sockaddr, addrbuf, sizeof(addrbuf));
3651         isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
3652                       DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
3653                       "lame server resolving '%s' (in '%s'?): %s",
3654                       namebuf, domainbuf, addrbuf);
3655 }
3656
3657 static inline isc_result_t
3658 same_question(fetchctx_t *fctx) {
3659         isc_result_t result;
3660         dns_message_t *message = fctx->rmessage;
3661         dns_name_t *name;
3662         dns_rdataset_t *rdataset;
3663
3664         /*
3665          * Caller must be holding the fctx lock.
3666          */
3667
3668         /*
3669          * XXXRTH  Currently we support only one question.
3670          */
3671         if (message->counts[DNS_SECTION_QUESTION] != 1)
3672                 return (DNS_R_FORMERR);
3673
3674         result = dns_message_firstname(message, DNS_SECTION_QUESTION);
3675         if (result != ISC_R_SUCCESS)
3676                 return (result);
3677         name = NULL;
3678         dns_message_currentname(message, DNS_SECTION_QUESTION, &name);
3679         rdataset = ISC_LIST_HEAD(name->list);
3680         INSIST(rdataset != NULL);
3681         INSIST(ISC_LIST_NEXT(rdataset, link) == NULL);
3682         if (fctx->type != rdataset->type ||
3683             fctx->res->rdclass != rdataset->rdclass ||
3684             !dns_name_equal(&fctx->name, name))
3685                 return (DNS_R_FORMERR);
3686
3687         return (ISC_R_SUCCESS);
3688 }
3689
3690 static void
3691 clone_results(fetchctx_t *fctx) {
3692         dns_fetchevent_t *event, *hevent;
3693         isc_result_t result;
3694         dns_name_t *name, *hname;
3695
3696         FCTXTRACE("clone_results");
3697
3698         /*
3699          * Set up any other events to have the same data as the first
3700          * event.
3701          *
3702          * Caller must be holding the appropriate lock.
3703          */
3704
3705         fctx->cloned = ISC_TRUE;
3706         hevent = ISC_LIST_HEAD(fctx->events);
3707         if (hevent == NULL)
3708                 return;
3709         hname = dns_fixedname_name(&hevent->foundname);
3710         for (event = ISC_LIST_NEXT(hevent, ev_link);
3711              event != NULL;
3712              event = ISC_LIST_NEXT(event, ev_link)) {
3713                 name = dns_fixedname_name(&event->foundname);
3714                 result = dns_name_copy(hname, name, NULL);
3715                 if (result != ISC_R_SUCCESS)
3716                         event->result = result;
3717                 else
3718                         event->result = hevent->result;
3719                 dns_db_attach(hevent->db, &event->db);
3720                 dns_db_attachnode(hevent->db, hevent->node, &event->node);
3721                 INSIST(hevent->rdataset != NULL);
3722                 INSIST(event->rdataset != NULL);
3723                 if (dns_rdataset_isassociated(hevent->rdataset))
3724                         dns_rdataset_clone(hevent->rdataset, event->rdataset);
3725                 INSIST(! (hevent->sigrdataset == NULL &&
3726                           event->sigrdataset != NULL));
3727                 if (hevent->sigrdataset != NULL &&
3728                     dns_rdataset_isassociated(hevent->sigrdataset) &&
3729                     event->sigrdataset != NULL)
3730                         dns_rdataset_clone(hevent->sigrdataset,
3731                                            event->sigrdataset);
3732         }
3733 }
3734
3735 #define CACHE(r)        (((r)->attributes & DNS_RDATASETATTR_CACHE) != 0)
3736 #define ANSWER(r)       (((r)->attributes & DNS_RDATASETATTR_ANSWER) != 0)
3737 #define ANSWERSIG(r)    (((r)->attributes & DNS_RDATASETATTR_ANSWERSIG) != 0)
3738 #define EXTERNAL(r)     (((r)->attributes & DNS_RDATASETATTR_EXTERNAL) != 0)
3739 #define CHAINING(r)     (((r)->attributes & DNS_RDATASETATTR_CHAINING) != 0)
3740 #define CHASE(r)        (((r)->attributes & DNS_RDATASETATTR_CHASE) != 0)
3741 #define CHECKNAMES(r)   (((r)->attributes & DNS_RDATASETATTR_CHECKNAMES) != 0)
3742
3743
3744 /*
3745  * Destroy '*fctx' if it is ready to be destroyed (i.e., if it has
3746  * no references and is no longer waiting for any events).  If this
3747  * was the last fctx in the resolver, destroy the resolver.
3748  *
3749  * Requires:
3750  *      '*fctx' is shutting down.
3751  */
3752 static void
3753 maybe_destroy(fetchctx_t *fctx) {
3754         unsigned int bucketnum;
3755         isc_boolean_t bucket_empty = ISC_FALSE;
3756         dns_resolver_t *res = fctx->res;
3757         dns_validator_t *validator, *next_validator;
3758
3759         REQUIRE(SHUTTINGDOWN(fctx));
3760
3761         if (fctx->pending != 0 || fctx->nqueries != 0)
3762                 return;
3763
3764         for (validator = ISC_LIST_HEAD(fctx->validators);
3765              validator != NULL; validator = next_validator) {
3766                 next_validator = ISC_LIST_NEXT(validator, link);
3767                 dns_validator_cancel(validator);
3768                 /*
3769                  * If this is a active validator wait for the cancel
3770                  * to complete before calling dns_validator_destroy().
3771                  */
3772                 if (validator == fctx->validator)
3773                         continue;
3774                 ISC_LIST_UNLINK(fctx->validators, validator, link);
3775                 dns_validator_destroy(&validator);
3776         }
3777
3778         bucketnum = fctx->bucketnum;
3779         LOCK(&res->buckets[bucketnum].lock);
3780         if (fctx->references == 0 && ISC_LIST_EMPTY(fctx->validators))
3781                 bucket_empty = fctx_destroy(fctx);
3782         UNLOCK(&res->buckets[bucketnum].lock);
3783
3784         if (bucket_empty)
3785                 empty_bucket(res);
3786 }
3787
3788 /*
3789  * The validator has finished.
3790  */
3791 static void
3792 validated(isc_task_t *task, isc_event_t *event) {
3793         isc_result_t result = ISC_R_SUCCESS;
3794         isc_result_t eresult = ISC_R_SUCCESS;
3795         isc_stdtime_t now;
3796         fetchctx_t *fctx;
3797         dns_validatorevent_t *vevent;
3798         dns_fetchevent_t *hevent;
3799         dns_rdataset_t *ardataset = NULL;
3800         dns_rdataset_t *asigrdataset = NULL;
3801         dns_dbnode_t *node = NULL;
3802         isc_boolean_t negative;
3803         isc_boolean_t chaining;
3804         isc_boolean_t sentresponse;
3805         isc_uint32_t ttl;
3806         dns_dbnode_t *nsnode = NULL;
3807         dns_name_t *name;
3808         dns_rdataset_t *rdataset;
3809         dns_rdataset_t *sigrdataset;
3810         dns_valarg_t *valarg;
3811         dns_adbaddrinfo_t *addrinfo;
3812
3813         UNUSED(task); /* for now */
3814
3815         REQUIRE(event->ev_type == DNS_EVENT_VALIDATORDONE);
3816         valarg = event->ev_arg;
3817         fctx = valarg->fctx;
3818         addrinfo = valarg->addrinfo;
3819         REQUIRE(VALID_FCTX(fctx));
3820         REQUIRE(!ISC_LIST_EMPTY(fctx->validators));
3821
3822         vevent = (dns_validatorevent_t *)event;
3823
3824         FCTXTRACE("received validation completion event");
3825
3826         ISC_LIST_UNLINK(fctx->validators, vevent->validator, link);
3827         fctx->validator = NULL;
3828
3829         /*
3830          * Destroy the validator early so that we can
3831          * destroy the fctx if necessary.
3832          */
3833         dns_validator_destroy(&vevent->validator);
3834         isc_mem_put(fctx->res->buckets[fctx->bucketnum].mctx,
3835                     valarg, sizeof(*valarg));
3836
3837         negative = ISC_TF(vevent->rdataset == NULL);
3838
3839         sentresponse = ISC_TF((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0);
3840
3841         /*
3842          * If shutting down, ignore the results.  Check to see if we're
3843          * done waiting for validator completions and ADB pending events; if
3844          * so, destroy the fctx.
3845          */
3846         if (SHUTTINGDOWN(fctx) && !sentresponse) {
3847                 maybe_destroy(fctx);    /* Locks bucket. */
3848                 goto cleanup_event;
3849         }
3850
3851         LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
3852
3853         /*
3854          * If chaining, we need to make sure that the right result code is
3855          * returned, and that the rdatasets are bound.
3856          */
3857         if (vevent->result == ISC_R_SUCCESS &&
3858             !negative &&
3859             vevent->rdataset != NULL &&
3860             CHAINING(vevent->rdataset))
3861         {
3862                 if (vevent->rdataset->type == dns_rdatatype_cname)
3863                         eresult = DNS_R_CNAME;
3864                 else {
3865                         INSIST(vevent->rdataset->type == dns_rdatatype_dname);
3866                         eresult = DNS_R_DNAME;
3867                 }
3868                 chaining = ISC_TRUE;
3869         } else
3870                 chaining = ISC_FALSE;
3871
3872         /*
3873          * Either we're not shutting down, or we are shutting down but want
3874          * to cache the result anyway (if this was a validation started by
3875          * a query with cd set)
3876          */
3877
3878         hevent = ISC_LIST_HEAD(fctx->events);
3879         if (hevent != NULL) {
3880                 if (!negative && !chaining &&
3881                     (fctx->type == dns_rdatatype_any ||
3882                      fctx->type == dns_rdatatype_rrsig ||
3883                      fctx->type == dns_rdatatype_sig)) {
3884                         /*
3885                          * Don't bind rdatasets; the caller
3886                          * will iterate the node.
3887                          */
3888                 } else {
3889                         ardataset = hevent->rdataset;
3890                         asigrdataset = hevent->sigrdataset;
3891                 }
3892         }
3893
3894         if (vevent->result != ISC_R_SUCCESS) {
3895                 FCTXTRACE("validation failed");
3896                 inc_stats(fctx->res, dns_resstatscounter_valfail);
3897                 fctx->valfail++;
3898                 fctx->vresult = vevent->result;
3899                 result = ISC_R_NOTFOUND;
3900                 if (vevent->rdataset != NULL)
3901                         result = dns_db_findnode(fctx->cache, vevent->name,
3902                                                  ISC_TRUE, &node);
3903                 if (result == ISC_R_SUCCESS)
3904                         (void)dns_db_deleterdataset(fctx->cache, node, NULL,
3905                                                     vevent->type, 0);
3906                 if (result == ISC_R_SUCCESS && vevent->sigrdataset != NULL)
3907                         (void)dns_db_deleterdataset(fctx->cache, node, NULL,
3908                                                     dns_rdatatype_rrsig,
3909                                                     vevent->type);
3910                 if (result == ISC_R_SUCCESS)
3911                         dns_db_detachnode(fctx->cache, &node);
3912                 result = vevent->result;
3913                 add_bad(fctx, addrinfo, result, badns_validation);
3914                 isc_event_free(&event);
3915                 UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
3916                 INSIST(fctx->validator == NULL);
3917                 fctx->validator = ISC_LIST_HEAD(fctx->validators);
3918                 if (fctx->validator != NULL) {
3919                         dns_validator_send(fctx->validator);
3920                 } else if (sentresponse)
3921                         fctx_done(fctx, result, __LINE__); /* Locks bucket. */
3922                 else
3923                         fctx_try(fctx, ISC_TRUE);       /* Locks bucket. */
3924                 return;
3925         }
3926
3927         isc_stdtime_get(&now);
3928
3929         if (negative) {
3930                 dns_rdatatype_t covers;
3931                 FCTXTRACE("nonexistence validation OK");
3932
3933                 inc_stats(fctx->res, dns_resstatscounter_valnegsuccess);
3934
3935                 if (fctx->rmessage->rcode == dns_rcode_nxdomain)
3936                         covers = dns_rdatatype_any;
3937                 else
3938                         covers = fctx->type;
3939
3940                 result = dns_db_findnode(fctx->cache, vevent->name, ISC_TRUE,
3941                                          &node);
3942                 if (result != ISC_R_SUCCESS)
3943                         goto noanswer_response;
3944
3945                 /*
3946                  * If we are asking for a SOA record set the cache time
3947                  * to zero to facilitate locating the containing zone of
3948                  * a arbitrary zone.
3949                  */
3950                 ttl = fctx->res->view->maxncachettl;
3951                 if (fctx->type == dns_rdatatype_soa &&
3952                     covers == dns_rdatatype_any &&
3953                     fctx->res->zero_no_soa_ttl)
3954                         ttl = 0;
3955
3956                 result = ncache_adderesult(fctx->rmessage, fctx->cache, node,
3957                                            covers, now, ttl,
3958                                            ardataset, &eresult);
3959                 if (result != ISC_R_SUCCESS)
3960                         goto noanswer_response;
3961                 goto answer_response;
3962         } else
3963                 inc_stats(fctx->res, dns_resstatscounter_valsuccess);
3964
3965         FCTXTRACE("validation OK");
3966
3967         if (vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF] != NULL) {
3968
3969                 result = dns_rdataset_addnoqname(vevent->rdataset,
3970                                    vevent->proofs[DNS_VALIDATOR_NOQNAMEPROOF]);
3971                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
3972                 INSIST(vevent->sigrdataset != NULL);
3973                 vevent->sigrdataset->ttl = vevent->rdataset->ttl;
3974         }
3975
3976         /*
3977          * The data was already cached as pending data.
3978          * Re-cache it as secure and bind the cached
3979          * rdatasets to the first event on the fetch
3980          * event list.
3981          */
3982         result = dns_db_findnode(fctx->cache, vevent->name, ISC_TRUE, &node);
3983         if (result != ISC_R_SUCCESS)
3984                 goto noanswer_response;
3985
3986         result = dns_db_addrdataset(fctx->cache, node, NULL, now,
3987                                     vevent->rdataset, 0, ardataset);
3988         if (result != ISC_R_SUCCESS &&
3989             result != DNS_R_UNCHANGED)
3990                 goto noanswer_response;
3991         if (ardataset != NULL && ardataset->type == 0) {
3992                 if (NXDOMAIN(ardataset))
3993                         eresult = DNS_R_NCACHENXDOMAIN;
3994                 else
3995                         eresult = DNS_R_NCACHENXRRSET;
3996         } else if (vevent->sigrdataset != NULL) {
3997                 result = dns_db_addrdataset(fctx->cache, node, NULL, now,
3998                                             vevent->sigrdataset, 0,
3999                                             asigrdataset);
4000                 if (result != ISC_R_SUCCESS &&
4001                     result != DNS_R_UNCHANGED)
4002                         goto noanswer_response;
4003         }
4004
4005         if (sentresponse) {
4006                 /*
4007                  * If we only deferred the destroy because we wanted to cache
4008                  * the data, destroy now.
4009                  */
4010                 dns_db_detachnode(fctx->cache, &node);
4011                 UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4012                 if (SHUTTINGDOWN(fctx))
4013                         maybe_destroy(fctx);    /* Locks bucket. */
4014                 goto cleanup_event;
4015         }
4016
4017         if (!ISC_LIST_EMPTY(fctx->validators)) {
4018                 INSIST(!negative);
4019                 INSIST(fctx->type == dns_rdatatype_any ||
4020                        fctx->type == dns_rdatatype_rrsig ||
4021                        fctx->type == dns_rdatatype_sig);
4022                 /*
4023                  * Don't send a response yet - we have
4024                  * more rdatasets that still need to
4025                  * be validated.
4026                  */
4027                 dns_db_detachnode(fctx->cache, &node);
4028                 UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4029                 dns_validator_send(ISC_LIST_HEAD(fctx->validators));
4030                 goto cleanup_event;
4031         }
4032
4033  answer_response:
4034         /*
4035          * Cache any NS/NSEC records that happened to be validated.
4036          */
4037         result = dns_message_firstname(fctx->rmessage, DNS_SECTION_AUTHORITY);
4038         while (result == ISC_R_SUCCESS) {
4039                 name = NULL;
4040                 dns_message_currentname(fctx->rmessage, DNS_SECTION_AUTHORITY,
4041                                         &name);
4042                 for (rdataset = ISC_LIST_HEAD(name->list);
4043                      rdataset != NULL;
4044                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
4045                         if ((rdataset->type != dns_rdatatype_ns &&
4046                              rdataset->type != dns_rdatatype_nsec) ||
4047                             rdataset->trust != dns_trust_secure)
4048                                 continue;
4049                         for (sigrdataset = ISC_LIST_HEAD(name->list);
4050                              sigrdataset != NULL;
4051                              sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4052                                 if (sigrdataset->type != dns_rdatatype_rrsig ||
4053                                     sigrdataset->covers != rdataset->type)
4054                                         continue;
4055                                 break;
4056                         }
4057                         if (sigrdataset == NULL ||
4058                             sigrdataset->trust != dns_trust_secure)
4059                                 continue;
4060                         result = dns_db_findnode(fctx->cache, name, ISC_TRUE,
4061                                                  &nsnode);
4062                         if (result != ISC_R_SUCCESS)
4063                                 continue;
4064
4065                         result = dns_db_addrdataset(fctx->cache, nsnode, NULL,
4066                                                     now, rdataset, 0, NULL);
4067                         if (result == ISC_R_SUCCESS)
4068                                 result = dns_db_addrdataset(fctx->cache, nsnode,
4069                                                             NULL, now,
4070                                                             sigrdataset, 0,
4071                                                             NULL);
4072                         dns_db_detachnode(fctx->cache, &nsnode);
4073                 }
4074                 result = dns_message_nextname(fctx->rmessage,
4075                                               DNS_SECTION_AUTHORITY);
4076         }
4077
4078         result = ISC_R_SUCCESS;
4079
4080         /*
4081          * Respond with an answer, positive or negative,
4082          * as opposed to an error.  'node' must be non-NULL.
4083          */
4084
4085         fctx->attributes |= FCTX_ATTR_HAVEANSWER;
4086
4087         if (hevent != NULL) {
4088                 hevent->result = eresult;
4089                 RUNTIME_CHECK(dns_name_copy(vevent->name,
4090                               dns_fixedname_name(&hevent->foundname), NULL)
4091                               == ISC_R_SUCCESS);
4092                 dns_db_attach(fctx->cache, &hevent->db);
4093                 dns_db_transfernode(fctx->cache, &node, &hevent->node);
4094                 clone_results(fctx);
4095         }
4096
4097  noanswer_response:
4098         if (node != NULL)
4099                 dns_db_detachnode(fctx->cache, &node);
4100
4101         UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4102
4103         fctx_done(fctx, result, __LINE__); /* Locks bucket. */
4104
4105  cleanup_event:
4106         INSIST(node == NULL);
4107         isc_event_free(&event);
4108 }
4109
4110 static inline isc_result_t
4111 cache_name(fetchctx_t *fctx, dns_name_t *name, dns_adbaddrinfo_t *addrinfo,
4112            isc_stdtime_t now)
4113 {
4114         dns_rdataset_t *rdataset, *sigrdataset;
4115         dns_rdataset_t *addedrdataset, *ardataset, *asigrdataset;
4116         dns_rdataset_t *valrdataset = NULL, *valsigrdataset = NULL;
4117         dns_dbnode_t *node, **anodep;
4118         dns_db_t **adbp;
4119         dns_name_t *aname;
4120         dns_resolver_t *res;
4121         isc_boolean_t need_validation, secure_domain, have_answer;
4122         isc_result_t result, eresult;
4123         dns_fetchevent_t *event;
4124         unsigned int options;
4125         isc_task_t *task;
4126         isc_boolean_t fail;
4127         unsigned int valoptions = 0;
4128
4129         /*
4130          * The appropriate bucket lock must be held.
4131          */
4132
4133         res = fctx->res;
4134         need_validation = ISC_FALSE;
4135         secure_domain = ISC_FALSE;
4136         have_answer = ISC_FALSE;
4137         eresult = ISC_R_SUCCESS;
4138         task = res->buckets[fctx->bucketnum].task;
4139
4140         /*
4141          * Is DNSSEC validation required for this name?
4142          */
4143         if (res->view->enablevalidation) {
4144                 result = dns_keytable_issecuredomain(res->view->secroots, name,
4145                                                      &secure_domain);
4146                 if (result != ISC_R_SUCCESS)
4147                         return (result);
4148
4149                 if (!secure_domain && res->view->dlv != NULL) {
4150                         valoptions = DNS_VALIDATOR_DLV;
4151                         secure_domain = ISC_TRUE;
4152                 }
4153         }
4154
4155         if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
4156                 need_validation = ISC_FALSE;
4157         else
4158                 need_validation = secure_domain;
4159
4160         adbp = NULL;
4161         aname = NULL;
4162         anodep = NULL;
4163         ardataset = NULL;
4164         asigrdataset = NULL;
4165         event = NULL;
4166         if ((name->attributes & DNS_NAMEATTR_ANSWER) != 0 &&
4167             !need_validation) {
4168                 have_answer = ISC_TRUE;
4169                 event = ISC_LIST_HEAD(fctx->events);
4170                 if (event != NULL) {
4171                         adbp = &event->db;
4172                         aname = dns_fixedname_name(&event->foundname);
4173                         result = dns_name_copy(name, aname, NULL);
4174                         if (result != ISC_R_SUCCESS)
4175                                 return (result);
4176                         anodep = &event->node;
4177                         /*
4178                          * If this is an ANY, SIG or RRSIG query, we're not
4179                          * going to return any rdatasets, unless we encountered
4180                          * a CNAME or DNAME as "the answer".  In this case,
4181                          * we're going to return DNS_R_CNAME or DNS_R_DNAME
4182                          * and we must set up the rdatasets.
4183                          */
4184                         if ((fctx->type != dns_rdatatype_any &&
4185                              fctx->type != dns_rdatatype_rrsig &&
4186                              fctx->type != dns_rdatatype_sig) ||
4187                             (name->attributes & DNS_NAMEATTR_CHAINING) != 0) {
4188                                 ardataset = event->rdataset;
4189                                 asigrdataset = event->sigrdataset;
4190                         }
4191                 }
4192         }
4193
4194         /*
4195          * Find or create the cache node.
4196          */
4197         node = NULL;
4198         result = dns_db_findnode(fctx->cache, name, ISC_TRUE, &node);
4199         if (result != ISC_R_SUCCESS)
4200                 return (result);
4201
4202         /*
4203          * Cache or validate each cacheable rdataset.
4204          */
4205         fail = ISC_TF((fctx->res->options & DNS_RESOLVER_CHECKNAMESFAIL) != 0);
4206         for (rdataset = ISC_LIST_HEAD(name->list);
4207              rdataset != NULL;
4208              rdataset = ISC_LIST_NEXT(rdataset, link)) {
4209                 if (!CACHE(rdataset))
4210                         continue;
4211                 if (CHECKNAMES(rdataset)) {
4212                         char namebuf[DNS_NAME_FORMATSIZE];
4213                         char typebuf[DNS_RDATATYPE_FORMATSIZE];
4214                         char classbuf[DNS_RDATATYPE_FORMATSIZE];
4215
4216                         dns_name_format(name, namebuf, sizeof(namebuf));
4217                         dns_rdatatype_format(rdataset->type, typebuf,
4218                                              sizeof(typebuf));
4219                         dns_rdataclass_format(rdataset->rdclass, classbuf,
4220                                               sizeof(classbuf));
4221                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
4222                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
4223                                       "check-names %s %s/%s/%s",
4224                                       fail ? "failure" : "warning",
4225                                       namebuf, typebuf, classbuf);
4226                         if (fail) {
4227                                 if (ANSWER(rdataset)) {
4228                                         dns_db_detachnode(fctx->cache, &node);
4229                                         return (DNS_R_BADNAME);
4230                                 }
4231                                 continue;
4232                         }
4233                 }
4234
4235                 /*
4236                  * Enforce the configure maximum cache TTL.
4237                  */
4238                 if (rdataset->ttl > res->view->maxcachettl)
4239                         rdataset->ttl = res->view->maxcachettl;
4240
4241                 /*
4242                  * If this RRset is in a secure domain, is in bailiwick,
4243                  * and is not glue, attempt DNSSEC validation.  (We do not
4244                  * attempt to validate glue or out-of-bailiwick data--even
4245                  * though there might be some performance benefit to doing
4246                  * so--because it makes it simpler and safer to ensure that
4247                  * records from a secure domain are only cached if validated
4248                  * within the context of a query to the domain that owns
4249                  * them.)
4250                  */
4251                 if (secure_domain && rdataset->trust != dns_trust_glue &&
4252                     !EXTERNAL(rdataset)) {
4253                         dns_trust_t trust;
4254
4255                         /*
4256                          * RRSIGs are validated as part of validating the
4257                          * type they cover.
4258                          */
4259                         if (rdataset->type == dns_rdatatype_rrsig)
4260                                 continue;
4261                         /*
4262                          * Find the SIG for this rdataset, if we have it.
4263                          */
4264                         for (sigrdataset = ISC_LIST_HEAD(name->list);
4265                              sigrdataset != NULL;
4266                              sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
4267                                 if (sigrdataset->type == dns_rdatatype_rrsig &&
4268                                     sigrdataset->covers == rdataset->type)
4269                                         break;
4270                         }
4271                         if (sigrdataset == NULL) {
4272                                 if (!ANSWER(rdataset) && need_validation) {
4273                                         /*
4274                                          * Ignore non-answer rdatasets that
4275                                          * are missing signatures.
4276                                          */
4277                                         continue;
4278                                 }
4279                         }
4280
4281                         /*
4282                          * Normalize the rdataset and sigrdataset TTLs.
4283                          */
4284                         if (sigrdataset != NULL) {
4285                                 rdataset->ttl = ISC_MIN(rdataset->ttl,
4286                                                         sigrdataset->ttl);
4287                                 sigrdataset->ttl = rdataset->ttl;
4288                         }
4289
4290                         /*
4291                          * Cache this rdataset/sigrdataset pair as
4292                          * pending data.  Track whether it was additional
4293                          * or not.
4294                          */
4295                         if (rdataset->trust == dns_trust_additional)
4296                                 trust = dns_trust_pending_additional;
4297                         else
4298                                 trust = dns_trust_pending_answer;
4299
4300                         rdataset->trust = trust;
4301                         if (sigrdataset != NULL)
4302                                 sigrdataset->trust = trust;
4303                         if (!need_validation || !ANSWER(rdataset)) {
4304                                 addedrdataset = ardataset;
4305                                 result = dns_db_addrdataset(fctx->cache, node,
4306                                                             NULL, now, rdataset,
4307                                                             0, addedrdataset);
4308                                 if (result == DNS_R_UNCHANGED) {
4309                                         result = ISC_R_SUCCESS;
4310                                         if (!need_validation &&
4311                                             ardataset != NULL &&
4312                                             ardataset->type == 0) {
4313                                                 /*
4314                                                  * The answer in the cache is
4315                                                  * better than the answer we
4316                                                  * found, and is a negative
4317                                                  * cache entry, so we must set
4318                                                  * eresult appropriately.
4319                                                  */
4320                                                 if (NXDOMAIN(ardataset))
4321                                                         eresult =
4322                                                            DNS_R_NCACHENXDOMAIN;
4323                                                 else
4324                                                         eresult =
4325                                                            DNS_R_NCACHENXRRSET;
4326                                                 /*
4327                                                  * We have a negative response
4328                                                  * from the cache so don't
4329                                                  * attempt to add the RRSIG
4330                                                  * rrset.
4331                                                  */
4332                                                 continue;
4333                                         }
4334                                 }
4335                                 if (result != ISC_R_SUCCESS)
4336                                         break;
4337                                 if (sigrdataset != NULL) {
4338                                         addedrdataset = asigrdataset;
4339                                         result = dns_db_addrdataset(fctx->cache,
4340                                                                 node, NULL, now,
4341                                                                 sigrdataset, 0,
4342                                                                 addedrdataset);
4343                                         if (result == DNS_R_UNCHANGED)
4344                                                 result = ISC_R_SUCCESS;
4345                                         if (result != ISC_R_SUCCESS)
4346                                                 break;
4347                                 } else if (!ANSWER(rdataset))
4348                                         continue;
4349                         }
4350
4351                         if (ANSWER(rdataset) && need_validation) {
4352                                 if (fctx->type != dns_rdatatype_any &&
4353                                     fctx->type != dns_rdatatype_rrsig &&
4354                                     fctx->type != dns_rdatatype_sig) {
4355                                         /*
4356                                          * This is The Answer.  We will
4357                                          * validate it, but first we cache
4358                                          * the rest of the response - it may
4359                                          * contain useful keys.
4360                                          */
4361                                         INSIST(valrdataset == NULL &&
4362                                                valsigrdataset == NULL);
4363                                         valrdataset = rdataset;
4364                                         valsigrdataset = sigrdataset;
4365                                 } else {
4366                                         /*
4367                                          * This is one of (potentially)
4368                                          * multiple answers to an ANY
4369                                          * or SIG query.  To keep things
4370                                          * simple, we just start the
4371                                          * validator right away rather
4372                                          * than caching first and
4373                                          * having to remember which
4374                                          * rdatasets needed validation.
4375                                          */
4376                                         result = valcreate(fctx, addrinfo,
4377                                                            name, rdataset->type,
4378                                                            rdataset,
4379                                                            sigrdataset,
4380                                                            valoptions, task);
4381                                         /*
4382                                          * Defer any further validations.
4383                                          * This prevents multiple validators
4384                                          * from manipulating fctx->rmessage
4385                                          * simultaneously.
4386                                          */
4387                                         valoptions |= DNS_VALIDATOR_DEFER;
4388                                 }
4389                         } else if (CHAINING(rdataset)) {
4390                                 if (rdataset->type == dns_rdatatype_cname)
4391                                         eresult = DNS_R_CNAME;
4392                                 else {
4393                                         INSIST(rdataset->type ==
4394                                                dns_rdatatype_dname);
4395                                         eresult = DNS_R_DNAME;
4396                                 }
4397                         }
4398                 } else if (!EXTERNAL(rdataset)) {
4399                         /*
4400                          * It's OK to cache this rdataset now.
4401                          */
4402                         if (ANSWER(rdataset))
4403                                 addedrdataset = ardataset;
4404                         else if (ANSWERSIG(rdataset))
4405                                 addedrdataset = asigrdataset;
4406                         else
4407                                 addedrdataset = NULL;
4408                         if (CHAINING(rdataset)) {
4409                                 if (rdataset->type == dns_rdatatype_cname)
4410                                         eresult = DNS_R_CNAME;
4411                                 else {
4412                                         INSIST(rdataset->type ==
4413                                                dns_rdatatype_dname);
4414                                         eresult = DNS_R_DNAME;
4415                                 }
4416                         }
4417                         if (rdataset->trust == dns_trust_glue &&
4418                             (rdataset->type == dns_rdatatype_ns ||
4419                              (rdataset->type == dns_rdatatype_rrsig &&
4420                               rdataset->covers == dns_rdatatype_ns))) {
4421                                 /*
4422                                  * If the trust level is 'dns_trust_glue'
4423                                  * then we are adding data from a referral
4424                                  * we got while executing the search algorithm.
4425                                  * New referral data always takes precedence
4426                                  * over the existing cache contents.
4427                                  */
4428                                 options = DNS_DBADD_FORCE;
4429                         } else
4430                                 options = 0;
4431                         /*
4432                          * Now we can add the rdataset.
4433                          */
4434                         result = dns_db_addrdataset(fctx->cache,
4435                                                     node, NULL, now,
4436                                                     rdataset,
4437                                                     options,
4438                                                     addedrdataset);
4439                         if (result == DNS_R_UNCHANGED) {
4440                                 if (ANSWER(rdataset) &&
4441                                     ardataset != NULL &&
4442                                     ardataset->type == 0) {
4443                                         /*
4444                                          * The answer in the cache is better
4445                                          * than the answer we found, and is
4446                                          * a negative cache entry, so we
4447                                          * must set eresult appropriately.
4448                                          */
4449                                         if (NXDOMAIN(ardataset))
4450                                                 eresult = DNS_R_NCACHENXDOMAIN;
4451                                         else
4452                                                 eresult = DNS_R_NCACHENXRRSET;
4453                                 }
4454                                 result = ISC_R_SUCCESS;
4455                         } else if (result != ISC_R_SUCCESS)
4456                                 break;
4457                 }
4458         }
4459
4460         if (valrdataset != NULL)
4461                 result = valcreate(fctx, addrinfo, name, fctx->type,
4462                                    valrdataset, valsigrdataset, valoptions,
4463                                    task);
4464
4465         if (result == ISC_R_SUCCESS && have_answer) {
4466                 fctx->attributes |= FCTX_ATTR_HAVEANSWER;
4467                 if (event != NULL) {
4468                         /*
4469                          * Negative results must be indicated in event->result.
4470                          */
4471                         if (dns_rdataset_isassociated(event->rdataset) &&
4472                             event->rdataset->type == dns_rdatatype_none) {
4473                                 INSIST(eresult == DNS_R_NCACHENXDOMAIN ||
4474                                        eresult == DNS_R_NCACHENXRRSET);
4475                         }
4476                         event->result = eresult;
4477                         dns_db_attach(fctx->cache, adbp);
4478                         dns_db_transfernode(fctx->cache, &node, anodep);
4479                         clone_results(fctx);
4480                 }
4481         }
4482
4483         if (node != NULL)
4484                 dns_db_detachnode(fctx->cache, &node);
4485
4486         return (result);
4487 }
4488
4489 static inline isc_result_t
4490 cache_message(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, isc_stdtime_t now)
4491 {
4492         isc_result_t result;
4493         dns_section_t section;
4494         dns_name_t *name;
4495
4496         FCTXTRACE("cache_message");
4497
4498         fctx->attributes &= ~FCTX_ATTR_WANTCACHE;
4499
4500         LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4501
4502         for (section = DNS_SECTION_ANSWER;
4503              section <= DNS_SECTION_ADDITIONAL;
4504              section++) {
4505                 result = dns_message_firstname(fctx->rmessage, section);
4506                 while (result == ISC_R_SUCCESS) {
4507                         name = NULL;
4508                         dns_message_currentname(fctx->rmessage, section,
4509                                                 &name);
4510                         if ((name->attributes & DNS_NAMEATTR_CACHE) != 0) {
4511                                 result = cache_name(fctx, name, addrinfo, now);
4512                                 if (result != ISC_R_SUCCESS)
4513                                         break;
4514                         }
4515                         result = dns_message_nextname(fctx->rmessage, section);
4516                 }
4517                 if (result != ISC_R_NOMORE)
4518                         break;
4519         }
4520         if (result == ISC_R_NOMORE)
4521                 result = ISC_R_SUCCESS;
4522
4523         UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
4524
4525         return (result);
4526 }
4527
4528 /*
4529  * Do what dns_ncache_add() does, and then compute an appropriate eresult.
4530  */
4531 static isc_result_t
4532 ncache_adderesult(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
4533                   dns_rdatatype_t covers, isc_stdtime_t now, dns_ttl_t maxttl,
4534                   dns_rdataset_t *ardataset,
4535                   isc_result_t *eresultp)
4536 {
4537         isc_result_t result;
4538         dns_rdataset_t rdataset;
4539
4540         if (ardataset == NULL) {
4541                 dns_rdataset_init(&rdataset);
4542                 ardataset = &rdataset;
4543         }
4544         result = dns_ncache_add(message, cache, node, covers, now,
4545                                 maxttl, ardataset);
4546         if (result == DNS_R_UNCHANGED || result == ISC_R_SUCCESS) {
4547                 /*
4548                  * If the cache now contains a negative entry and we
4549                  * care about whether it is DNS_R_NCACHENXDOMAIN or
4550                  * DNS_R_NCACHENXRRSET then extract it.
4551                  */
4552                 if (ardataset->type == 0) {
4553                         /*
4554                          * The cache data is a negative cache entry.
4555                          */
4556                         if (NXDOMAIN(ardataset))
4557                                 *eresultp = DNS_R_NCACHENXDOMAIN;
4558                         else
4559                                 *eresultp = DNS_R_NCACHENXRRSET;
4560                 } else {
4561                         /*
4562                          * Either we don't care about the nature of the
4563                          * cache rdataset (because no fetch is interested
4564                          * in the outcome), or the cache rdataset is not
4565                          * a negative cache entry.  Whichever case it is,
4566                          * we can return success.
4567                          *
4568                          * XXXRTH  There's a CNAME/DNAME problem here.
4569                          */
4570                         *eresultp = ISC_R_SUCCESS;
4571                 }
4572                 result = ISC_R_SUCCESS;
4573         }
4574         if (ardataset == &rdataset && dns_rdataset_isassociated(ardataset))
4575                 dns_rdataset_disassociate(ardataset);
4576
4577         return (result);
4578 }
4579
4580 static inline isc_result_t
4581 ncache_message(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
4582                dns_rdatatype_t covers, isc_stdtime_t now)
4583 {
4584         isc_result_t result, eresult;
4585         dns_name_t *name;
4586         dns_resolver_t *res;
4587         dns_db_t **adbp;
4588         dns_dbnode_t *node, **anodep;
4589         dns_rdataset_t *ardataset;
4590         isc_boolean_t need_validation, secure_domain;
4591         dns_name_t *aname;
4592         dns_fetchevent_t *event;
4593         isc_uint32_t ttl;
4594         unsigned int valoptions = 0;
4595
4596         FCTXTRACE("ncache_message");
4597
4598         fctx->attributes &= ~FCTX_ATTR_WANTNCACHE;
4599
4600         res = fctx->res;
4601         need_validation = ISC_FALSE;
4602         secure_domain = ISC_FALSE;
4603         eresult = ISC_R_SUCCESS;
4604         name = &fctx->name;
4605         node = NULL;
4606
4607         /*
4608          * XXXMPA remove when we follow cnames and adjust the setting
4609          * of FCTX_ATTR_WANTNCACHE in noanswer_response().
4610          */
4611         INSIST(fctx->rmessage->counts[DNS_SECTION_ANSWER] == 0);
4612
4613         /*
4614          * Is DNSSEC validation required for this name?
4615          */
4616         if (fctx->res->view->enablevalidation) {
4617                 result = dns_keytable_issecuredomain(res->view->secroots, name,
4618                                                      &secure_domain);
4619                 if (result != ISC_R_SUCCESS)
4620                         return (result);
4621
4622                 if (!secure_domain && res->view->dlv != NULL) {
4623                         valoptions = DNS_VALIDATOR_DLV;
4624                         secure_domain = ISC_TRUE;
4625                 }
4626         }
4627
4628         if ((fctx->options & DNS_FETCHOPT_NOVALIDATE) != 0)
4629                 need_validation = ISC_FALSE;
4630         else
4631                 need_validation = secure_domain;
4632
4633         if (secure_domain) {
4634                 /*
4635                  * Mark all rdatasets as pending.
4636                  */
4637                 dns_rdataset_t *trdataset;
4638                 dns_name_t *tname;
4639
4640                 result = dns_message_firstname(fctx->rmessage,
4641                                                DNS_SECTION_AUTHORITY);
4642                 while (result == ISC_R_SUCCESS) {
4643                         tname = NULL;
4644                         dns_message_currentname(fctx->rmessage,
4645                                                 DNS_SECTION_AUTHORITY,
4646                                                 &tname);
4647                         for (trdataset = ISC_LIST_HEAD(tname->list);
4648                              trdataset != NULL;
4649                              trdataset = ISC_LIST_NEXT(trdataset, link))
4650                                 trdataset->trust = dns_trust_pending_answer;
4651                         result = dns_message_nextname(fctx->rmessage,
4652                                                       DNS_SECTION_AUTHORITY);
4653                 }
4654                 if (result != ISC_R_NOMORE)
4655                         return (result);
4656
4657         }
4658
4659         if (need_validation) {
4660                 /*
4661                  * Do negative response validation.
4662                  */
4663                 result = valcreate(fctx, addrinfo, name, fctx->type,
4664                                    NULL, NULL, valoptions,
4665                                    res->buckets[fctx->bucketnum].task);
4666                 /*
4667                  * If validation is necessary, return now.  Otherwise continue
4668                  * to process the message, letting the validation complete
4669                  * in its own good time.
4670                  */
4671                 return (result);
4672         }
4673
4674         LOCK(&res->buckets[fctx->bucketnum].lock);
4675
4676         adbp = NULL;
4677         aname = NULL;
4678         anodep = NULL;
4679         ardataset = NULL;
4680         if (!HAVE_ANSWER(fctx)) {
4681                 event = ISC_LIST_HEAD(fctx->events);
4682                 if (event != NULL) {
4683                         adbp = &event->db;
4684                         aname = dns_fixedname_name(&event->foundname);
4685                         result = dns_name_copy(name, aname, NULL);
4686                         if (result != ISC_R_SUCCESS)
4687                                 goto unlock;
4688                         anodep = &event->node;
4689                         ardataset = event->rdataset;
4690                 }
4691         } else
4692                 event = NULL;
4693
4694         result = dns_db_findnode(fctx->cache, name, ISC_TRUE, &node);
4695         if (result != ISC_R_SUCCESS)
4696                 goto unlock;
4697
4698         /*
4699          * If we are asking for a SOA record set the cache time
4700          * to zero to facilitate locating the containing zone of
4701          * a arbitrary zone.
4702          */
4703         ttl = fctx->res->view->maxncachettl;
4704         if (fctx->type == dns_rdatatype_soa &&
4705             covers == dns_rdatatype_any &&
4706             fctx->res->zero_no_soa_ttl)
4707                 ttl = 0;
4708
4709         result = ncache_adderesult(fctx->rmessage, fctx->cache, node,
4710                                    covers, now, ttl, ardataset, &eresult);
4711         if (result != ISC_R_SUCCESS)
4712                 goto unlock;
4713
4714         if (!HAVE_ANSWER(fctx)) {
4715                 fctx->attributes |= FCTX_ATTR_HAVEANSWER;
4716                 if (event != NULL) {
4717                         event->result = eresult;
4718                         dns_db_attach(fctx->cache, adbp);
4719                         dns_db_transfernode(fctx->cache, &node, anodep);
4720                         clone_results(fctx);
4721                 }
4722         }
4723
4724  unlock:
4725         UNLOCK(&res->buckets[fctx->bucketnum].lock);
4726
4727         if (node != NULL)
4728                 dns_db_detachnode(fctx->cache, &node);
4729
4730         return (result);
4731 }
4732
4733 static inline void
4734 mark_related(dns_name_t *name, dns_rdataset_t *rdataset,
4735              isc_boolean_t external, isc_boolean_t gluing)
4736 {
4737         name->attributes |= DNS_NAMEATTR_CACHE;
4738         if (gluing) {
4739                 rdataset->trust = dns_trust_glue;
4740                 /*
4741                  * Glue with 0 TTL causes problems.  We force the TTL to
4742                  * 1 second to prevent this.
4743                  */
4744                 if (rdataset->ttl == 0)
4745                         rdataset->ttl = 1;
4746         } else
4747                 rdataset->trust = dns_trust_additional;
4748         /*
4749          * Avoid infinite loops by only marking new rdatasets.
4750          */
4751         if (!CACHE(rdataset)) {
4752                 name->attributes |= DNS_NAMEATTR_CHASE;
4753                 rdataset->attributes |= DNS_RDATASETATTR_CHASE;
4754         }
4755         rdataset->attributes |= DNS_RDATASETATTR_CACHE;
4756         if (external)
4757                 rdataset->attributes |= DNS_RDATASETATTR_EXTERNAL;
4758 }
4759
4760 static isc_result_t
4761 check_related(void *arg, dns_name_t *addname, dns_rdatatype_t type) {
4762         fetchctx_t *fctx = arg;
4763         isc_result_t result;
4764         dns_name_t *name;
4765         dns_rdataset_t *rdataset;
4766         isc_boolean_t external;
4767         dns_rdatatype_t rtype;
4768         isc_boolean_t gluing;
4769
4770         REQUIRE(VALID_FCTX(fctx));
4771
4772         if (GLUING(fctx))
4773                 gluing = ISC_TRUE;
4774         else
4775                 gluing = ISC_FALSE;
4776         name = NULL;
4777         rdataset = NULL;
4778         result = dns_message_findname(fctx->rmessage, DNS_SECTION_ADDITIONAL,
4779                                       addname, dns_rdatatype_any, 0, &name,
4780                                       NULL);
4781         if (result == ISC_R_SUCCESS) {
4782                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
4783                 if (type == dns_rdatatype_a) {
4784                         for (rdataset = ISC_LIST_HEAD(name->list);
4785                              rdataset != NULL;
4786                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
4787                                 if (rdataset->type == dns_rdatatype_rrsig)
4788                                         rtype = rdataset->covers;
4789                                 else
4790                                         rtype = rdataset->type;
4791                                 if (rtype == dns_rdatatype_a ||
4792                                     rtype == dns_rdatatype_aaaa)
4793                                         mark_related(name, rdataset, external,
4794                                                      gluing);
4795                         }
4796                 } else {
4797                         result = dns_message_findtype(name, type, 0,
4798                                                       &rdataset);
4799                         if (result == ISC_R_SUCCESS) {
4800                                 mark_related(name, rdataset, external, gluing);
4801                                 /*
4802                                  * Do we have its SIG too?
4803                                  */
4804                                 rdataset = NULL;
4805                                 result = dns_message_findtype(name,
4806                                                       dns_rdatatype_rrsig,
4807                                                       type, &rdataset);
4808                                 if (result == ISC_R_SUCCESS)
4809                                         mark_related(name, rdataset, external,
4810                                                      gluing);
4811                         }
4812                 }
4813         }
4814
4815         return (ISC_R_SUCCESS);
4816 }
4817
4818 static void
4819 chase_additional(fetchctx_t *fctx) {
4820         isc_boolean_t rescan;
4821         dns_section_t section = DNS_SECTION_ADDITIONAL;
4822         isc_result_t result;
4823
4824  again:
4825         rescan = ISC_FALSE;
4826
4827         for (result = dns_message_firstname(fctx->rmessage, section);
4828              result == ISC_R_SUCCESS;
4829              result = dns_message_nextname(fctx->rmessage, section)) {
4830                 dns_name_t *name = NULL;
4831                 dns_rdataset_t *rdataset;
4832                 dns_message_currentname(fctx->rmessage, DNS_SECTION_ADDITIONAL,
4833                                         &name);
4834                 if ((name->attributes & DNS_NAMEATTR_CHASE) == 0)
4835                         continue;
4836                 name->attributes &= ~DNS_NAMEATTR_CHASE;
4837                 for (rdataset = ISC_LIST_HEAD(name->list);
4838                      rdataset != NULL;
4839                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
4840                         if (CHASE(rdataset)) {
4841                                 rdataset->attributes &= ~DNS_RDATASETATTR_CHASE;
4842                                 (void)dns_rdataset_additionaldata(rdataset,
4843                                                                   check_related,
4844                                                                   fctx);
4845                                 rescan = ISC_TRUE;
4846                         }
4847                 }
4848         }
4849         if (rescan)
4850                 goto again;
4851 }
4852
4853 static inline isc_result_t
4854 cname_target(dns_rdataset_t *rdataset, dns_name_t *tname) {
4855         isc_result_t result;
4856         dns_rdata_t rdata = DNS_RDATA_INIT;
4857         dns_rdata_cname_t cname;
4858
4859         result = dns_rdataset_first(rdataset);
4860         if (result != ISC_R_SUCCESS)
4861                 return (result);
4862         dns_rdataset_current(rdataset, &rdata);
4863         result = dns_rdata_tostruct(&rdata, &cname, NULL);
4864         if (result != ISC_R_SUCCESS)
4865                 return (result);
4866         dns_name_init(tname, NULL);
4867         dns_name_clone(&cname.cname, tname);
4868         dns_rdata_freestruct(&cname);
4869
4870         return (ISC_R_SUCCESS);
4871 }
4872
4873 static inline isc_result_t
4874 dname_target(dns_rdataset_t *rdataset, dns_name_t *qname, dns_name_t *oname,
4875              dns_fixedname_t *fixeddname)
4876 {
4877         isc_result_t result;
4878         dns_rdata_t rdata = DNS_RDATA_INIT;
4879         unsigned int nlabels;
4880         int order;
4881         dns_namereln_t namereln;
4882         dns_rdata_dname_t dname;
4883         dns_fixedname_t prefix;
4884
4885         /*
4886          * Get the target name of the DNAME.
4887          */
4888
4889         result = dns_rdataset_first(rdataset);
4890         if (result != ISC_R_SUCCESS)
4891                 return (result);
4892         dns_rdataset_current(rdataset, &rdata);
4893         result = dns_rdata_tostruct(&rdata, &dname, NULL);
4894         if (result != ISC_R_SUCCESS)
4895                 return (result);
4896
4897         /*
4898          * Get the prefix of qname.
4899          */
4900         namereln = dns_name_fullcompare(qname, oname, &order, &nlabels);
4901         if (namereln != dns_namereln_subdomain) {
4902                 dns_rdata_freestruct(&dname);
4903                 return (DNS_R_FORMERR);
4904         }
4905         dns_fixedname_init(&prefix);
4906         dns_name_split(qname, nlabels, dns_fixedname_name(&prefix), NULL);
4907         dns_fixedname_init(fixeddname);
4908         result = dns_name_concatenate(dns_fixedname_name(&prefix),
4909                                       &dname.dname,
4910                                       dns_fixedname_name(fixeddname), NULL);
4911         dns_rdata_freestruct(&dname);
4912         return (result);
4913 }
4914
4915 /*
4916  * Handle a no-answer response (NXDOMAIN, NXRRSET, or referral).
4917  * If bind8_ns_resp is ISC_TRUE, this is a suspected BIND 8
4918  * response to an NS query that should be treated as a referral
4919  * even though the NS records occur in the answer section
4920  * rather than the authority section.
4921  */
4922 static isc_result_t
4923 noanswer_response(fetchctx_t *fctx, dns_name_t *oqname,
4924                   isc_boolean_t bind8_ns_resp)
4925 {
4926         isc_result_t result;
4927         dns_message_t *message;
4928         dns_name_t *name, *qname, *ns_name, *soa_name, *ds_name;
4929         dns_rdataset_t *rdataset, *ns_rdataset;
4930         isc_boolean_t aa, negative_response;
4931         dns_rdatatype_t type;
4932         dns_section_t section =
4933                 bind8_ns_resp ? DNS_SECTION_ANSWER : DNS_SECTION_AUTHORITY;
4934
4935         FCTXTRACE("noanswer_response");
4936
4937         message = fctx->rmessage;
4938
4939         /*
4940          * Setup qname.
4941          */
4942         if (oqname == NULL) {
4943                 /*
4944                  * We have a normal, non-chained negative response or
4945                  * referral.
4946                  */
4947                 if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
4948                         aa = ISC_TRUE;
4949                 else
4950                         aa = ISC_FALSE;
4951                 qname = &fctx->name;
4952         } else {
4953                 /*
4954                  * We're being invoked by answer_response() after it has
4955                  * followed a CNAME/DNAME chain.
4956                  */
4957                 qname = oqname;
4958                 aa = ISC_FALSE;
4959                 /*
4960                  * If the current qname is not a subdomain of the query
4961                  * domain, there's no point in looking at the authority
4962                  * section without doing DNSSEC validation.
4963                  *
4964                  * Until we do that validation, we'll just return success
4965                  * in this case.
4966                  */
4967                 if (!dns_name_issubdomain(qname, &fctx->domain))
4968                         return (ISC_R_SUCCESS);
4969         }
4970
4971         /*
4972          * We have to figure out if this is a negative response, or a
4973          * referral.
4974          */
4975
4976         /*
4977          * Sometimes we can tell if its a negative response by looking at
4978          * the message header.
4979          */
4980         negative_response = ISC_FALSE;
4981         if (message->rcode == dns_rcode_nxdomain ||
4982             (message->counts[DNS_SECTION_ANSWER] == 0 &&
4983              message->counts[DNS_SECTION_AUTHORITY] == 0))
4984                 negative_response = ISC_TRUE;
4985
4986         /*
4987          * Process the authority section.
4988          */
4989         ns_name = NULL;
4990         ns_rdataset = NULL;
4991         soa_name = NULL;
4992         ds_name = NULL;
4993         result = dns_message_firstname(message, section);
4994         while (result == ISC_R_SUCCESS) {
4995                 name = NULL;
4996                 dns_message_currentname(message, section, &name);
4997                 if (dns_name_issubdomain(name, &fctx->domain)) {
4998                         /*
4999                          * Look for NS/SOA RRsets first.
5000                          */
5001                         for (rdataset = ISC_LIST_HEAD(name->list);
5002                              rdataset != NULL;
5003                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5004                                 type = rdataset->type;
5005                                 if (type == dns_rdatatype_rrsig)
5006                                         type = rdataset->covers;
5007                                 if (((type == dns_rdatatype_ns ||
5008                                       type == dns_rdatatype_soa) &&
5009                                      !dns_name_issubdomain(qname, name)))
5010                                         return (DNS_R_FORMERR);
5011                                 if (type == dns_rdatatype_ns) {
5012                                         /*
5013                                          * NS or RRSIG NS.
5014                                          *
5015                                          * Only one set of NS RRs is allowed.
5016                                          */
5017                                         if (rdataset->type ==
5018                                             dns_rdatatype_ns) {
5019                                                 if (ns_name != NULL &&
5020                                                     name != ns_name)
5021                                                         return (DNS_R_FORMERR);
5022                                                 ns_name = name;
5023                                                 ns_rdataset = rdataset;
5024                                         }
5025                                         name->attributes |=
5026                                                 DNS_NAMEATTR_CACHE;
5027                                         rdataset->attributes |=
5028                                                 DNS_RDATASETATTR_CACHE;
5029                                         rdataset->trust = dns_trust_glue;
5030                                 }
5031                                 if (type == dns_rdatatype_soa) {
5032                                         /*
5033                                          * SOA, or RRSIG SOA.
5034                                          *
5035                                          * Only one SOA is allowed.
5036                                          */
5037                                         if (rdataset->type ==
5038                                             dns_rdatatype_soa) {
5039                                                 if (soa_name != NULL &&
5040                                                     name != soa_name)
5041                                                         return (DNS_R_FORMERR);
5042                                                 soa_name = name;
5043                                         }
5044                                         name->attributes |=
5045                                                 DNS_NAMEATTR_NCACHE;
5046                                         rdataset->attributes |=
5047                                                 DNS_RDATASETATTR_NCACHE;
5048                                         if (aa)
5049                                                 rdataset->trust =
5050                                                     dns_trust_authauthority;
5051                                         else
5052                                                 rdataset->trust =
5053                                                         dns_trust_additional;
5054                                 }
5055                         }
5056                 }
5057                 result = dns_message_nextname(message, section);
5058                 if (result == ISC_R_NOMORE)
5059                         break;
5060                 else if (result != ISC_R_SUCCESS)
5061                         return (result);
5062         }
5063
5064         /*
5065          * A negative response has a SOA record (Type 2)
5066          * and a optional NS RRset (Type 1) or it has neither
5067          * a SOA or a NS RRset (Type 3, handled above) or
5068          * rcode is NXDOMAIN (handled above) in which case
5069          * the NS RRset is allowed (Type 4).
5070          */
5071         if (soa_name != NULL)
5072                 negative_response = ISC_TRUE;
5073
5074         result = dns_message_firstname(message, section);
5075         while (result == ISC_R_SUCCESS) {
5076                 name = NULL;
5077                 dns_message_currentname(message, section, &name);
5078                 if (dns_name_issubdomain(name, &fctx->domain)) {
5079                         for (rdataset = ISC_LIST_HEAD(name->list);
5080                              rdataset != NULL;
5081                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5082                                 type = rdataset->type;
5083                                 if (type == dns_rdatatype_rrsig)
5084                                         type = rdataset->covers;
5085                                 if (type == dns_rdatatype_nsec) {
5086                                         /*
5087                                          * NSEC or RRSIG NSEC.
5088                                          */
5089                                         if (negative_response) {
5090                                                 name->attributes |=
5091                                                         DNS_NAMEATTR_NCACHE;
5092                                                 rdataset->attributes |=
5093                                                         DNS_RDATASETATTR_NCACHE;
5094                                         } else {
5095                                                 name->attributes |=
5096                                                         DNS_NAMEATTR_CACHE;
5097                                                 rdataset->attributes |=
5098                                                         DNS_RDATASETATTR_CACHE;
5099                                         }
5100                                         if (aa)
5101                                                 rdataset->trust =
5102                                                     dns_trust_authauthority;
5103                                         else
5104                                                 rdataset->trust =
5105                                                         dns_trust_additional;
5106                                         /*
5107                                          * No additional data needs to be
5108                                          * marked.
5109                                          */
5110                                 } else if (type == dns_rdatatype_ds) {
5111                                         /*
5112                                          * DS or SIG DS.
5113                                          *
5114                                          * These should only be here if
5115                                          * this is a referral, and there
5116                                          * should only be one DS.
5117                                          */
5118                                         if (ns_name == NULL)
5119                                                 return (DNS_R_FORMERR);
5120                                         if (rdataset->type ==
5121                                             dns_rdatatype_ds) {
5122                                                 if (ds_name != NULL &&
5123                                                     name != ds_name)
5124                                                         return (DNS_R_FORMERR);
5125                                                 ds_name = name;
5126                                         }
5127                                         name->attributes |=
5128                                                 DNS_NAMEATTR_CACHE;
5129                                         rdataset->attributes |=
5130                                                 DNS_RDATASETATTR_CACHE;
5131                                         if (aa)
5132                                                 rdataset->trust =
5133                                                     dns_trust_authauthority;
5134                                         else
5135                                                 rdataset->trust =
5136                                                         dns_trust_additional;
5137                                 }
5138                         }
5139                 }
5140                 result = dns_message_nextname(message, section);
5141                 if (result == ISC_R_NOMORE)
5142                         break;
5143                 else if (result != ISC_R_SUCCESS)
5144                         return (result);
5145         }
5146
5147         /*
5148          * Trigger lookups for DNS nameservers.
5149          */
5150         if (negative_response && message->rcode == dns_rcode_noerror &&
5151             fctx->type == dns_rdatatype_ds && soa_name != NULL &&
5152             dns_name_equal(soa_name, qname) &&
5153             !dns_name_equal(qname, dns_rootname))
5154                 return (DNS_R_CHASEDSSERVERS);
5155
5156         /*
5157          * Did we find anything?
5158          */
5159         if (!negative_response && ns_name == NULL) {
5160                 /*
5161                  * Nope.
5162                  */
5163                 if (oqname != NULL) {
5164                         /*
5165                          * We've already got a partial CNAME/DNAME chain,
5166                          * and haven't found else anything useful here, but
5167                          * no error has occurred since we have an answer.
5168                          */
5169                         return (ISC_R_SUCCESS);
5170                 } else {
5171                         /*
5172                          * The responder is insane.
5173                          */
5174                         return (DNS_R_FORMERR);
5175                 }
5176         }
5177
5178         /*
5179          * If we found both NS and SOA, they should be the same name.
5180          */
5181         if (ns_name != NULL && soa_name != NULL && ns_name != soa_name)
5182                 return (DNS_R_FORMERR);
5183
5184         /*
5185          * Do we have a referral?  (We only want to follow a referral if
5186          * we're not following a chain.)
5187          */
5188         if (!negative_response && ns_name != NULL && oqname == NULL) {
5189                 /*
5190                  * We already know ns_name is a subdomain of fctx->domain.
5191                  * If ns_name is equal to fctx->domain, we're not making
5192                  * progress.  We return DNS_R_FORMERR so that we'll keep
5193                  * trying other servers.
5194                  */
5195                 if (dns_name_equal(ns_name, &fctx->domain))
5196                         return (DNS_R_FORMERR);
5197
5198                 /*
5199                  * If the referral name is not a parent of the query
5200                  * name, consider the responder insane.
5201                  */
5202                 if (! dns_name_issubdomain(&fctx->name, ns_name)) {
5203                         FCTXTRACE("referral to non-parent");
5204                         return (DNS_R_FORMERR);
5205                 }
5206
5207                 /*
5208                  * Mark any additional data related to this rdataset.
5209                  * It's important that we do this before we change the
5210                  * query domain.
5211                  */
5212                 INSIST(ns_rdataset != NULL);
5213                 fctx->attributes |= FCTX_ATTR_GLUING;
5214                 (void)dns_rdataset_additionaldata(ns_rdataset, check_related,
5215                                                   fctx);
5216                 fctx->attributes &= ~FCTX_ATTR_GLUING;
5217                 /*
5218                  * NS rdatasets with 0 TTL cause problems.
5219                  * dns_view_findzonecut() will not find them when we
5220                  * try to follow the referral, and we'll SERVFAIL
5221                  * because the best nameservers are now above QDOMAIN.
5222                  * We force the TTL to 1 second to prevent this.
5223                  */
5224                 if (ns_rdataset->ttl == 0)
5225                         ns_rdataset->ttl = 1;
5226                 /*
5227                  * Set the current query domain to the referral name.
5228                  *
5229                  * XXXRTH  We should check if we're in forward-only mode, and
5230                  *              if so we should bail out.
5231                  */
5232                 INSIST(dns_name_countlabels(&fctx->domain) > 0);
5233                 dns_name_free(&fctx->domain,
5234                               fctx->res->buckets[fctx->bucketnum].mctx);
5235                 if (dns_rdataset_isassociated(&fctx->nameservers))
5236                         dns_rdataset_disassociate(&fctx->nameservers);
5237                 dns_name_init(&fctx->domain, NULL);
5238                 result = dns_name_dup(ns_name,
5239                                       fctx->res->buckets[fctx->bucketnum].mctx,
5240                                       &fctx->domain);
5241                 if (result != ISC_R_SUCCESS)
5242                         return (result);
5243                 fctx->attributes |= FCTX_ATTR_WANTCACHE;
5244                 return (DNS_R_DELEGATION);
5245         }
5246
5247         /*
5248          * Since we're not doing a referral, we don't want to cache any
5249          * NS RRs we may have found.
5250          */
5251         if (ns_name != NULL)
5252                 ns_name->attributes &= ~DNS_NAMEATTR_CACHE;
5253
5254         if (negative_response && oqname == NULL)
5255                 fctx->attributes |= FCTX_ATTR_WANTNCACHE;
5256
5257         return (ISC_R_SUCCESS);
5258 }
5259
5260 static isc_result_t
5261 answer_response(fetchctx_t *fctx) {
5262         isc_result_t result;
5263         dns_message_t *message;
5264         dns_name_t *name, *qname, tname;
5265         dns_rdataset_t *rdataset;
5266         isc_boolean_t done, external, chaining, aa, found, want_chaining;
5267         isc_boolean_t have_answer, found_cname, found_type, wanted_chaining;
5268         unsigned int aflag;
5269         dns_rdatatype_t type;
5270         dns_fixedname_t dname, fqname;
5271
5272         FCTXTRACE("answer_response");
5273
5274         message = fctx->rmessage;
5275
5276         /*
5277          * Examine the answer section, marking those rdatasets which are
5278          * part of the answer and should be cached.
5279          */
5280
5281         done = ISC_FALSE;
5282         found_cname = ISC_FALSE;
5283         found_type = ISC_FALSE;
5284         chaining = ISC_FALSE;
5285         have_answer = ISC_FALSE;
5286         want_chaining = ISC_FALSE;
5287         if ((message->flags & DNS_MESSAGEFLAG_AA) != 0)
5288                 aa = ISC_TRUE;
5289         else
5290                 aa = ISC_FALSE;
5291         qname = &fctx->name;
5292         type = fctx->type;
5293         result = dns_message_firstname(message, DNS_SECTION_ANSWER);
5294         while (!done && result == ISC_R_SUCCESS) {
5295                 name = NULL;
5296                 dns_message_currentname(message, DNS_SECTION_ANSWER, &name);
5297                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
5298                 if (dns_name_equal(name, qname)) {
5299                         wanted_chaining = ISC_FALSE;
5300                         for (rdataset = ISC_LIST_HEAD(name->list);
5301                              rdataset != NULL;
5302                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5303                                 found = ISC_FALSE;
5304                                 want_chaining = ISC_FALSE;
5305                                 aflag = 0;
5306                                 if (rdataset->type == type && !found_cname) {
5307                                         /*
5308                                          * We've found an ordinary answer.
5309                                          */
5310                                         found = ISC_TRUE;
5311                                         found_type = ISC_TRUE;
5312                                         done = ISC_TRUE;
5313                                         aflag = DNS_RDATASETATTR_ANSWER;
5314                                 } else if (type == dns_rdatatype_any) {
5315                                         /*
5316                                          * We've found an answer matching
5317                                          * an ANY query.  There may be
5318                                          * more.
5319                                          */
5320                                         found = ISC_TRUE;
5321                                         aflag = DNS_RDATASETATTR_ANSWER;
5322                                 } else if (rdataset->type == dns_rdatatype_rrsig
5323                                            && rdataset->covers == type
5324                                            && !found_cname) {
5325                                         /*
5326                                          * We've found a signature that
5327                                          * covers the type we're looking for.
5328                                          */
5329                                         found = ISC_TRUE;
5330                                         found_type = ISC_TRUE;
5331                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
5332                                 } else if (rdataset->type ==
5333                                            dns_rdatatype_cname
5334                                            && !found_type) {
5335                                         /*
5336                                          * We're looking for something else,
5337                                          * but we found a CNAME.
5338                                          *
5339                                          * Getting a CNAME response for some
5340                                          * query types is an error.
5341                                          */
5342                                         if (type == dns_rdatatype_rrsig ||
5343                                             type == dns_rdatatype_dnskey ||
5344                                             type == dns_rdatatype_nsec)
5345                                                 return (DNS_R_FORMERR);
5346                                         found = ISC_TRUE;
5347                                         found_cname = ISC_TRUE;
5348                                         want_chaining = ISC_TRUE;
5349                                         aflag = DNS_RDATASETATTR_ANSWER;
5350                                         result = cname_target(rdataset,
5351                                                               &tname);
5352                                         if (result != ISC_R_SUCCESS)
5353                                                 return (result);
5354                                 } else if (rdataset->type == dns_rdatatype_rrsig
5355                                            && rdataset->covers ==
5356                                            dns_rdatatype_cname
5357                                            && !found_type) {
5358                                         /*
5359                                          * We're looking for something else,
5360                                          * but we found a SIG CNAME.
5361                                          */
5362                                         found = ISC_TRUE;
5363                                         found_cname = ISC_TRUE;
5364                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
5365                                 }
5366
5367                                 if (found) {
5368                                         /*
5369                                          * We've found an answer to our
5370                                          * question.
5371                                          */
5372                                         name->attributes |=
5373                                                 DNS_NAMEATTR_CACHE;
5374                                         rdataset->attributes |=
5375                                                 DNS_RDATASETATTR_CACHE;
5376                                         rdataset->trust = dns_trust_answer;
5377                                         if (!chaining) {
5378                                                 /*
5379                                                  * This data is "the" answer
5380                                                  * to our question only if
5381                                                  * we're not chaining (i.e.
5382                                                  * if we haven't followed
5383                                                  * a CNAME or DNAME).
5384                                                  */
5385                                                 INSIST(!external);
5386                                                 if (aflag ==
5387                                                     DNS_RDATASETATTR_ANSWER)
5388                                                         have_answer = ISC_TRUE;
5389                                                 name->attributes |=
5390                                                         DNS_NAMEATTR_ANSWER;
5391                                                 rdataset->attributes |= aflag;
5392                                                 if (aa)
5393                                                         rdataset->trust =
5394                                                           dns_trust_authanswer;
5395                                         } else if (external) {
5396                                                 /*
5397                                                  * This data is outside of
5398                                                  * our query domain, and
5399                                                  * may not be cached.
5400                                                  */
5401                                                 rdataset->attributes |=
5402                                                     DNS_RDATASETATTR_EXTERNAL;
5403                                         }
5404
5405                                         /*
5406                                          * Mark any additional data related
5407                                          * to this rdataset.
5408                                          */
5409                                         (void)dns_rdataset_additionaldata(
5410                                                         rdataset,
5411                                                         check_related,
5412                                                         fctx);
5413
5414                                         /*
5415                                          * CNAME chaining.
5416                                          */
5417                                         if (want_chaining) {
5418                                                 wanted_chaining = ISC_TRUE;
5419                                                 name->attributes |=
5420                                                         DNS_NAMEATTR_CHAINING;
5421                                                 rdataset->attributes |=
5422                                                     DNS_RDATASETATTR_CHAINING;
5423                                                 qname = &tname;
5424                                         }
5425                                 }
5426                                 /*
5427                                  * We could add an "else" clause here and
5428                                  * log that we're ignoring this rdataset.
5429                                  */
5430                         }
5431                         /*
5432                          * If wanted_chaining is true, we've done
5433                          * some chaining as the result of processing
5434                          * this node, and thus we need to set
5435                          * chaining to true.
5436                          *
5437                          * We don't set chaining inside of the
5438                          * rdataset loop because doing that would
5439                          * cause us to ignore the signatures of
5440                          * CNAMEs.
5441                          */
5442                         if (wanted_chaining)
5443                                 chaining = ISC_TRUE;
5444                 } else {
5445                         /*
5446                          * Look for a DNAME (or its SIG).  Anything else is
5447                          * ignored.
5448                          */
5449                         wanted_chaining = ISC_FALSE;
5450                         for (rdataset = ISC_LIST_HEAD(name->list);
5451                              rdataset != NULL;
5452                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5453                                 isc_boolean_t found_dname = ISC_FALSE;
5454                                 found = ISC_FALSE;
5455                                 aflag = 0;
5456                                 if (rdataset->type == dns_rdatatype_dname) {
5457                                         /*
5458                                          * We're looking for something else,
5459                                          * but we found a DNAME.
5460                                          *
5461                                          * If we're not chaining, then the
5462                                          * DNAME should not be external.
5463                                          */
5464                                         if (!chaining && external)
5465                                                 return (DNS_R_FORMERR);
5466                                         found = ISC_TRUE;
5467                                         want_chaining = ISC_TRUE;
5468                                         aflag = DNS_RDATASETATTR_ANSWER;
5469                                         result = dname_target(rdataset,
5470                                                               qname, name,
5471                                                               &dname);
5472                                         if (result == ISC_R_NOSPACE) {
5473                                                 /*
5474                                                  * We can't construct the
5475                                                  * DNAME target.  Do not
5476                                                  * try to continue.
5477                                                  */
5478                                                 want_chaining = ISC_FALSE;
5479                                         } else if (result != ISC_R_SUCCESS)
5480                                                 return (result);
5481                                         else
5482                                                 found_dname = ISC_TRUE;
5483                                 } else if (rdataset->type == dns_rdatatype_rrsig
5484                                            && rdataset->covers ==
5485                                            dns_rdatatype_dname) {
5486                                         /*
5487                                          * We've found a signature that
5488                                          * covers the DNAME.
5489                                          */
5490                                         found = ISC_TRUE;
5491                                         aflag = DNS_RDATASETATTR_ANSWERSIG;
5492                                 }
5493
5494                                 if (found) {
5495                                         /*
5496                                          * We've found an answer to our
5497                                          * question.
5498                                          */
5499                                         name->attributes |=
5500                                                 DNS_NAMEATTR_CACHE;
5501                                         rdataset->attributes |=
5502                                                 DNS_RDATASETATTR_CACHE;
5503                                         rdataset->trust = dns_trust_answer;
5504                                         if (!chaining) {
5505                                                 /*
5506                                                  * This data is "the" answer
5507                                                  * to our question only if
5508                                                  * we're not chaining.
5509                                                  */
5510                                                 INSIST(!external);
5511                                                 if (aflag ==
5512                                                     DNS_RDATASETATTR_ANSWER)
5513                                                         have_answer = ISC_TRUE;
5514                                                 name->attributes |=
5515                                                         DNS_NAMEATTR_ANSWER;
5516                                                 rdataset->attributes |= aflag;
5517                                                 if (aa)
5518                                                         rdataset->trust =
5519                                                           dns_trust_authanswer;
5520                                         } else if (external) {
5521                                                 rdataset->attributes |=
5522                                                     DNS_RDATASETATTR_EXTERNAL;
5523                                         }
5524
5525                                         /*
5526                                          * DNAME chaining.
5527                                          */
5528                                         if (found_dname) {
5529                                                 /*
5530                                                  * Copy the dname into the
5531                                                  * qname fixed name.
5532                                                  *
5533                                                  * Although we check for
5534                                                  * failure of the copy
5535                                                  * operation, in practice it
5536                                                  * should never fail since
5537                                                  * we already know that the
5538                                                  * result fits in a fixedname.
5539                                                  */
5540                                                 dns_fixedname_init(&fqname);
5541                                                 result = dns_name_copy(
5542                                                   dns_fixedname_name(&dname),
5543                                                   dns_fixedname_name(&fqname),
5544                                                   NULL);
5545                                                 if (result != ISC_R_SUCCESS)
5546                                                         return (result);
5547                                                 wanted_chaining = ISC_TRUE;
5548                                                 name->attributes |=
5549                                                         DNS_NAMEATTR_CHAINING;
5550                                                 rdataset->attributes |=
5551                                                     DNS_RDATASETATTR_CHAINING;
5552                                                 qname = dns_fixedname_name(
5553                                                                    &fqname);
5554                                         }
5555                                 }
5556                         }
5557                         if (wanted_chaining)
5558                                 chaining = ISC_TRUE;
5559                 }
5560                 result = dns_message_nextname(message, DNS_SECTION_ANSWER);
5561         }
5562         if (result == ISC_R_NOMORE)
5563                 result = ISC_R_SUCCESS;
5564         if (result != ISC_R_SUCCESS)
5565                 return (result);
5566
5567         /*
5568          * We should have found an answer.
5569          */
5570         if (!have_answer)
5571                 return (DNS_R_FORMERR);
5572
5573         /*
5574          * This response is now potentially cacheable.
5575          */
5576         fctx->attributes |= FCTX_ATTR_WANTCACHE;
5577
5578         /*
5579          * Did chaining end before we got the final answer?
5580          */
5581         if (chaining) {
5582                 /*
5583                  * Yes.  This may be a negative reply, so hand off
5584                  * authority section processing to the noanswer code.
5585                  * If it isn't a noanswer response, no harm will be
5586                  * done.
5587                  */
5588                 return (noanswer_response(fctx, qname, ISC_FALSE));
5589         }
5590
5591         /*
5592          * We didn't end with an incomplete chain, so the rcode should be
5593          * "no error".
5594          */
5595         if (message->rcode != dns_rcode_noerror)
5596                 return (DNS_R_FORMERR);
5597
5598         /*
5599          * Examine the authority section (if there is one).
5600          *
5601          * We expect there to be only one owner name for all the rdatasets
5602          * in this section, and we expect that it is not external.
5603          */
5604         done = ISC_FALSE;
5605         result = dns_message_firstname(message, DNS_SECTION_AUTHORITY);
5606         while (!done && result == ISC_R_SUCCESS) {
5607                 name = NULL;
5608                 dns_message_currentname(message, DNS_SECTION_AUTHORITY, &name);
5609                 external = ISC_TF(!dns_name_issubdomain(name, &fctx->domain));
5610                 if (!external) {
5611                         /*
5612                          * We expect to find NS or SIG NS rdatasets, and
5613                          * nothing else.
5614                          */
5615                         for (rdataset = ISC_LIST_HEAD(name->list);
5616                              rdataset != NULL;
5617                              rdataset = ISC_LIST_NEXT(rdataset, link)) {
5618                                 if (rdataset->type == dns_rdatatype_ns ||
5619                                     (rdataset->type == dns_rdatatype_rrsig &&
5620                                      rdataset->covers == dns_rdatatype_ns)) {
5621                                         name->attributes |=
5622                                                 DNS_NAMEATTR_CACHE;
5623                                         rdataset->attributes |=
5624                                                 DNS_RDATASETATTR_CACHE;
5625                                         if (aa && !chaining)
5626                                                 rdataset->trust =
5627                                                     dns_trust_authauthority;
5628                                         else
5629                                                 rdataset->trust =
5630                                                     dns_trust_additional;
5631
5632                                         /*
5633                                          * Mark any additional data related
5634                                          * to this rdataset.
5635                                          */
5636                                         (void)dns_rdataset_additionaldata(
5637                                                         rdataset,
5638                                                         check_related,
5639                                                         fctx);
5640                                         done = ISC_TRUE;
5641                                 }
5642                         }
5643                 }
5644                 result = dns_message_nextname(message, DNS_SECTION_AUTHORITY);
5645         }
5646         if (result == ISC_R_NOMORE)
5647                 result = ISC_R_SUCCESS;
5648
5649         return (result);
5650 }
5651
5652 static void
5653 resume_dslookup(isc_task_t *task, isc_event_t *event) {
5654         dns_fetchevent_t *fevent;
5655         dns_resolver_t *res;
5656         fetchctx_t *fctx;
5657         isc_result_t result;
5658         isc_boolean_t bucket_empty = ISC_FALSE;
5659         isc_boolean_t locked = ISC_FALSE;
5660         unsigned int bucketnum;
5661         dns_rdataset_t nameservers;
5662         dns_fixedname_t fixed;
5663         dns_name_t *domain;
5664
5665         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
5666         fevent = (dns_fetchevent_t *)event;
5667         fctx = event->ev_arg;
5668         REQUIRE(VALID_FCTX(fctx));
5669         res = fctx->res;
5670
5671         UNUSED(task);
5672         FCTXTRACE("resume_dslookup");
5673
5674         if (fevent->node != NULL)
5675                 dns_db_detachnode(fevent->db, &fevent->node);
5676         if (fevent->db != NULL)
5677                 dns_db_detach(&fevent->db);
5678
5679         dns_rdataset_init(&nameservers);
5680
5681         bucketnum = fctx->bucketnum;
5682         if (fevent->result == ISC_R_CANCELED) {
5683                 dns_resolver_destroyfetch(&fctx->nsfetch);
5684                 fctx_done(fctx, ISC_R_CANCELED, __LINE__);
5685         } else if (fevent->result == ISC_R_SUCCESS) {
5686
5687                 FCTXTRACE("resuming DS lookup");
5688
5689                 dns_resolver_destroyfetch(&fctx->nsfetch);
5690                 if (dns_rdataset_isassociated(&fctx->nameservers))
5691                         dns_rdataset_disassociate(&fctx->nameservers);
5692                 dns_rdataset_clone(fevent->rdataset, &fctx->nameservers);
5693                 dns_name_free(&fctx->domain,
5694                               fctx->res->buckets[bucketnum].mctx);
5695                 dns_name_init(&fctx->domain, NULL);
5696                 result = dns_name_dup(&fctx->nsname,
5697                                       fctx->res->buckets[bucketnum].mctx,
5698                                       &fctx->domain);
5699                 if (result != ISC_R_SUCCESS) {
5700                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
5701                         goto cleanup;
5702                 }
5703                 /*
5704                  * Try again.
5705                  */
5706                 fctx_try(fctx, ISC_TRUE);
5707         } else {
5708                 unsigned int n;
5709                 dns_rdataset_t *nsrdataset = NULL;
5710
5711                 /*
5712                  * Retrieve state from fctx->nsfetch before we destroy it.
5713                  */
5714                 dns_fixedname_init(&fixed);
5715                 domain = dns_fixedname_name(&fixed);
5716                 dns_name_copy(&fctx->nsfetch->private->domain, domain, NULL);
5717                 if (dns_name_equal(&fctx->nsname, domain)) {
5718                         fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
5719                         dns_resolver_destroyfetch(&fctx->nsfetch);
5720                         goto cleanup;
5721                 }
5722                 if (dns_rdataset_isassociated(
5723                     &fctx->nsfetch->private->nameservers)) {
5724                         dns_rdataset_clone(
5725                             &fctx->nsfetch->private->nameservers,
5726                             &nameservers);
5727                         nsrdataset = &nameservers;
5728                 } else
5729                         domain = NULL;
5730                 dns_resolver_destroyfetch(&fctx->nsfetch);
5731                 n = dns_name_countlabels(&fctx->nsname);
5732                 dns_name_getlabelsequence(&fctx->nsname, 1, n - 1,
5733                                           &fctx->nsname);
5734
5735                 if (dns_rdataset_isassociated(fevent->rdataset))
5736                         dns_rdataset_disassociate(fevent->rdataset);
5737                 FCTXTRACE("continuing to look for parent's NS records");
5738                 result = dns_resolver_createfetch(fctx->res, &fctx->nsname,
5739                                                   dns_rdatatype_ns, domain,
5740                                                   nsrdataset, NULL, 0, task,
5741                                                   resume_dslookup, fctx,
5742                                                   &fctx->nsrrset, NULL,
5743                                                   &fctx->nsfetch);
5744                 if (result != ISC_R_SUCCESS)
5745                         fctx_done(fctx, result, __LINE__);
5746                 else {
5747                         LOCK(&res->buckets[bucketnum].lock);
5748                         locked = ISC_TRUE;
5749                         fctx->references++;
5750                 }
5751         }
5752
5753  cleanup:
5754         if (dns_rdataset_isassociated(&nameservers))
5755                 dns_rdataset_disassociate(&nameservers);
5756         if (dns_rdataset_isassociated(fevent->rdataset))
5757                 dns_rdataset_disassociate(fevent->rdataset);
5758         INSIST(fevent->sigrdataset == NULL);
5759         isc_event_free(&event);
5760         if (!locked)
5761                 LOCK(&res->buckets[bucketnum].lock);
5762         fctx->references--;
5763         if (fctx->references == 0)
5764                 bucket_empty = fctx_destroy(fctx);
5765         UNLOCK(&res->buckets[bucketnum].lock);
5766         if (bucket_empty)
5767                 empty_bucket(res);
5768 }
5769
5770 static inline void
5771 checknamessection(dns_message_t *message, dns_section_t section) {
5772         isc_result_t result;
5773         dns_name_t *name;
5774         dns_rdata_t rdata = DNS_RDATA_INIT;
5775         dns_rdataset_t *rdataset;
5776
5777         for (result = dns_message_firstname(message, section);
5778              result == ISC_R_SUCCESS;
5779              result = dns_message_nextname(message, section))
5780         {
5781                 name = NULL;
5782                 dns_message_currentname(message, section, &name);
5783                 for (rdataset = ISC_LIST_HEAD(name->list);
5784                      rdataset != NULL;
5785                      rdataset = ISC_LIST_NEXT(rdataset, link)) {
5786                         for (result = dns_rdataset_first(rdataset);
5787                              result == ISC_R_SUCCESS;
5788                              result = dns_rdataset_next(rdataset)) {
5789                                 dns_rdataset_current(rdataset, &rdata);
5790                                 if (!dns_rdata_checkowner(name, rdata.rdclass,
5791                                                           rdata.type,
5792                                                           ISC_FALSE) ||
5793                                     !dns_rdata_checknames(&rdata, name, NULL))
5794                                 {
5795                                         rdataset->attributes |=
5796                                                 DNS_RDATASETATTR_CHECKNAMES;
5797                                 }
5798                                 dns_rdata_reset(&rdata);
5799                         }
5800                 }
5801         }
5802 }
5803
5804 static void
5805 checknames(dns_message_t *message) {
5806
5807         checknamessection(message, DNS_SECTION_ANSWER);
5808         checknamessection(message, DNS_SECTION_AUTHORITY);
5809         checknamessection(message, DNS_SECTION_ADDITIONAL);
5810 }
5811
5812 /*
5813  * Log server NSID at log level 'level'
5814  */
5815 static isc_result_t
5816 log_nsid(dns_rdataset_t *opt, resquery_t *query, int level, isc_mem_t *mctx)
5817 {
5818         static const char hex[17] = "0123456789abcdef";
5819         char addrbuf[ISC_SOCKADDR_FORMATSIZE];
5820         isc_uint16_t optcode, nsid_len, buflen, i;
5821         isc_result_t result;
5822         isc_buffer_t nsidbuf;
5823         dns_rdata_t rdata;
5824         unsigned char *p, *buf, *nsid;
5825
5826         /* Extract rdata from OPT rdataset */
5827         result = dns_rdataset_first(opt);
5828         if (result != ISC_R_SUCCESS)
5829                 return (ISC_R_FAILURE);
5830
5831         dns_rdata_init(&rdata);
5832         dns_rdataset_current(opt, &rdata);
5833         if (rdata.length < 4)
5834                 return (ISC_R_FAILURE);
5835
5836         /* Check for NSID */
5837         isc_buffer_init(&nsidbuf, rdata.data, rdata.length);
5838         isc_buffer_add(&nsidbuf, rdata.length);
5839         optcode = isc_buffer_getuint16(&nsidbuf);
5840         nsid_len = isc_buffer_getuint16(&nsidbuf);
5841         if (optcode != DNS_OPT_NSID || nsid_len == 0)
5842                 return (ISC_R_FAILURE);
5843
5844         /* Allocate buffer for storing hex version of the NSID */
5845         buflen = nsid_len * 2 + 1;
5846         buf = isc_mem_get(mctx, buflen);
5847         if (buf == NULL)
5848                 return (ISC_R_NOSPACE);
5849
5850         /* Convert to hex */
5851         p = buf;
5852         nsid = rdata.data + 4;
5853         for (i = 0; i < nsid_len; i++) {
5854                 *p++ = hex[(nsid[0] >> 4) & 0xf];
5855                 *p++ = hex[nsid[0] & 0xf];
5856                 nsid++;
5857         }
5858         *p = '\0';
5859
5860         isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
5861                             sizeof(addrbuf));
5862         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
5863                       DNS_LOGMODULE_RESOLVER, level,
5864                       "received NSID '%s' from %s", buf, addrbuf);
5865
5866         /* Clean up */
5867         isc_mem_put(mctx, buf, buflen);
5868         return (ISC_R_SUCCESS);
5869 }
5870
5871 static void
5872 log_packet(dns_message_t *message, int level, isc_mem_t *mctx) {
5873         isc_buffer_t buffer;
5874         char *buf = NULL;
5875         int len = 1024;
5876         isc_result_t result;
5877
5878         if (! isc_log_wouldlog(dns_lctx, level))
5879                 return;
5880
5881         /*
5882          * Note that these are multiline debug messages.  We want a newline
5883          * to appear in the log after each message.
5884          */
5885
5886         do {
5887                 buf = isc_mem_get(mctx, len);
5888                 if (buf == NULL)
5889                         break;
5890                 isc_buffer_init(&buffer, buf, len);
5891                 result = dns_message_totext(message, &dns_master_style_debug,
5892                                             0, &buffer);
5893                 if (result == ISC_R_NOSPACE) {
5894                         isc_mem_put(mctx, buf, len);
5895                         len += 1024;
5896                 } else if (result == ISC_R_SUCCESS)
5897                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
5898                                       DNS_LOGMODULE_RESOLVER, level,
5899                                       "received packet:\n%.*s",
5900                                       (int)isc_buffer_usedlength(&buffer),
5901                                       buf);
5902         } while (result == ISC_R_NOSPACE);
5903
5904         if (buf != NULL)
5905                 isc_mem_put(mctx, buf, len);
5906 }
5907
5908 static void
5909 resquery_response(isc_task_t *task, isc_event_t *event) {
5910         isc_result_t result = ISC_R_SUCCESS;
5911         resquery_t *query = event->ev_arg;
5912         dns_dispatchevent_t *devent = (dns_dispatchevent_t *)event;
5913         isc_boolean_t keep_trying, get_nameservers, resend;
5914         isc_boolean_t truncated;
5915         dns_message_t *message;
5916         dns_rdataset_t *opt;
5917         fetchctx_t *fctx;
5918         dns_name_t *fname;
5919         dns_fixedname_t foundname;
5920         isc_stdtime_t now;
5921         isc_time_t tnow, *finish;
5922         dns_adbaddrinfo_t *addrinfo;
5923         unsigned int options;
5924         unsigned int findoptions;
5925         isc_result_t broken_server;
5926         badnstype_t broken_type = badns_response;
5927
5928         REQUIRE(VALID_QUERY(query));
5929         fctx = query->fctx;
5930         options = query->options;
5931         REQUIRE(VALID_FCTX(fctx));
5932         REQUIRE(event->ev_type == DNS_EVENT_DISPATCH);
5933
5934         QTRACE("response");
5935
5936         if (isc_sockaddr_pf(&query->addrinfo->sockaddr) == PF_INET)
5937                 inc_stats(fctx->res, dns_resstatscounter_responsev4);
5938         else
5939                 inc_stats(fctx->res, dns_resstatscounter_responsev6);
5940
5941         (void)isc_timer_touch(fctx->timer);
5942
5943         keep_trying = ISC_FALSE;
5944         broken_server = ISC_R_SUCCESS;
5945         get_nameservers = ISC_FALSE;
5946         resend = ISC_FALSE;
5947         truncated = ISC_FALSE;
5948         finish = NULL;
5949
5950         if (fctx->res->exiting) {
5951                 result = ISC_R_SHUTTINGDOWN;
5952                 goto done;
5953         }
5954
5955         fctx->timeouts = 0;
5956         fctx->timeout = ISC_FALSE;
5957
5958         /*
5959          * XXXRTH  We should really get the current time just once.  We
5960          *              need a routine to convert from an isc_time_t to an
5961          *              isc_stdtime_t.
5962          */
5963         TIME_NOW(&tnow);
5964         finish = &tnow;
5965         isc_stdtime_get(&now);
5966
5967         /*
5968          * Did the dispatcher have a problem?
5969          */
5970         if (devent->result != ISC_R_SUCCESS) {
5971                 if (devent->result == ISC_R_EOF &&
5972                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
5973                         /*
5974                          * The problem might be that they
5975                          * don't understand EDNS0.  Turn it
5976                          * off and try again.
5977                          */
5978                         options |= DNS_FETCHOPT_NOEDNS0;
5979                         resend = ISC_TRUE;
5980                         /*
5981                          * Remember that they don't like EDNS0.
5982                          */
5983                         dns_adb_changeflags(fctx->adb,
5984                                             query->addrinfo,
5985                                             DNS_FETCHOPT_NOEDNS0,
5986                                             DNS_FETCHOPT_NOEDNS0);
5987                 } else {
5988                         /*
5989                          * There's no hope for this query.
5990                          */
5991                         keep_trying = ISC_TRUE;
5992
5993                         /*
5994                          * If this is a network error on an exclusive query
5995                          * socket, mark the server as bad so that we won't try
5996                          * it for this fetch again.
5997                          */
5998                         if (query->exclusivesocket &&
5999                             (devent->result == ISC_R_HOSTUNREACH ||
6000                              devent->result == ISC_R_NETUNREACH ||
6001                              devent->result == ISC_R_CONNREFUSED ||
6002                              devent->result == ISC_R_CANCELED)) {
6003                                     broken_server = devent->result;
6004                                     broken_type = badns_unreachable;
6005                         }
6006                 }
6007                 goto done;
6008         }
6009
6010         message = fctx->rmessage;
6011
6012         if (query->tsig != NULL) {
6013                 result = dns_message_setquerytsig(message, query->tsig);
6014                 if (result != ISC_R_SUCCESS)
6015                         goto done;
6016         }
6017
6018         if (query->tsigkey) {
6019                 result = dns_message_settsigkey(message, query->tsigkey);
6020                 if (result != ISC_R_SUCCESS)
6021                         goto done;
6022         }
6023
6024         result = dns_message_parse(message, &devent->buffer, 0);
6025         if (result != ISC_R_SUCCESS) {
6026                 switch (result) {
6027                 case ISC_R_UNEXPECTEDEND:
6028                         if (!message->question_ok ||
6029                             (message->flags & DNS_MESSAGEFLAG_TC) == 0 ||
6030                             (options & DNS_FETCHOPT_TCP) != 0) {
6031                                 /*
6032                                  * Either the message ended prematurely,
6033                                  * and/or wasn't marked as being truncated,
6034                                  * and/or this is a response to a query we
6035                                  * sent over TCP.  In all of these cases,
6036                                  * something is wrong with the remote
6037                                  * server and we don't want to retry using
6038                                  * TCP.
6039                                  */
6040                                 if ((query->options & DNS_FETCHOPT_NOEDNS0)
6041                                     == 0) {
6042                                         /*
6043                                          * The problem might be that they
6044                                          * don't understand EDNS0.  Turn it
6045                                          * off and try again.
6046                                          */
6047                                         options |= DNS_FETCHOPT_NOEDNS0;
6048                                         resend = ISC_TRUE;
6049                                         /*
6050                                          * Remember that they don't like EDNS0.
6051                                          */
6052                                         dns_adb_changeflags(
6053                                                         fctx->adb,
6054                                                         query->addrinfo,
6055                                                         DNS_FETCHOPT_NOEDNS0,
6056                                                         DNS_FETCHOPT_NOEDNS0);
6057                                         inc_stats(fctx->res,
6058                                                  dns_resstatscounter_edns0fail);
6059                                 } else {
6060                                         broken_server = result;
6061                                         keep_trying = ISC_TRUE;
6062                                 }
6063                                 goto done;
6064                         }
6065                         /*
6066                          * We defer retrying via TCP for a bit so we can
6067                          * check out this message further.
6068                          */
6069                         truncated = ISC_TRUE;
6070                         break;
6071                 case DNS_R_FORMERR:
6072                         if ((query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
6073                                 /*
6074                                  * The problem might be that they
6075                                  * don't understand EDNS0.  Turn it
6076                                  * off and try again.
6077                                  */
6078                                 options |= DNS_FETCHOPT_NOEDNS0;
6079                                 resend = ISC_TRUE;
6080                                 /*
6081                                  * Remember that they don't like EDNS0.
6082                                  */
6083                                 dns_adb_changeflags(fctx->adb,
6084                                                     query->addrinfo,
6085                                                     DNS_FETCHOPT_NOEDNS0,
6086                                                     DNS_FETCHOPT_NOEDNS0);
6087                                 inc_stats(fctx->res,
6088                                                  dns_resstatscounter_edns0fail);
6089                         } else {
6090                                 broken_server = DNS_R_UNEXPECTEDRCODE;
6091                                 keep_trying = ISC_TRUE;
6092                         }
6093                         goto done;
6094                 default:
6095                         /*
6096                          * Something bad has happened.
6097                          */
6098                         goto done;
6099                 }
6100         }
6101
6102
6103         /*
6104          * Log the incoming packet.
6105          */
6106         log_packet(message, ISC_LOG_DEBUG(10), fctx->res->mctx);
6107
6108         /*
6109          * Did we request NSID?  If so, and if the response contains
6110          * NSID data, log it at INFO level.
6111          */
6112         opt = dns_message_getopt(message);
6113         if (opt != NULL && (query->options & DNS_FETCHOPT_WANTNSID) != 0)
6114                 log_nsid(opt, query, ISC_LOG_INFO, fctx->res->mctx);
6115
6116         /*
6117          * If the message is signed, check the signature.  If not, this
6118          * returns success anyway.
6119          */
6120         result = dns_message_checksig(message, fctx->res->view);
6121         if (result != ISC_R_SUCCESS)
6122                 goto done;
6123
6124         /*
6125          * The dispatcher should ensure we only get responses with QR set.
6126          */
6127         INSIST((message->flags & DNS_MESSAGEFLAG_QR) != 0);
6128         /*
6129          * INSIST() that the message comes from the place we sent it to,
6130          * since the dispatch code should ensure this.
6131          *
6132          * INSIST() that the message id is correct (this should also be
6133          * ensured by the dispatch code).
6134          */
6135
6136
6137         /*
6138          * Deal with truncated responses by retrying using TCP.
6139          */
6140         if ((message->flags & DNS_MESSAGEFLAG_TC) != 0)
6141                 truncated = ISC_TRUE;
6142
6143         if (truncated) {
6144                 inc_stats(fctx->res, dns_resstatscounter_truncated);
6145                 if ((options & DNS_FETCHOPT_TCP) != 0) {
6146                         broken_server = DNS_R_TRUNCATEDTCP;
6147                         keep_trying = ISC_TRUE;
6148                 } else {
6149                         options |= DNS_FETCHOPT_TCP;
6150                         resend = ISC_TRUE;
6151                 }
6152                 goto done;
6153         }
6154
6155         /*
6156          * Is it a query response?
6157          */
6158         if (message->opcode != dns_opcode_query) {
6159                 /* XXXRTH Log */
6160                 broken_server = DNS_R_UNEXPECTEDOPCODE;
6161                 keep_trying = ISC_TRUE;
6162                 goto done;
6163         }
6164
6165         /*
6166          * Update statistics about erroneous responses.
6167          */
6168         if (message->rcode != dns_rcode_noerror) {
6169                 switch (message->rcode) {
6170                 case dns_rcode_nxdomain:
6171                         inc_stats(fctx->res, dns_resstatscounter_nxdomain);
6172                         break;
6173                 case dns_rcode_servfail:
6174                         inc_stats(fctx->res, dns_resstatscounter_servfail);
6175                         break;
6176                 case dns_rcode_formerr:
6177                         inc_stats(fctx->res, dns_resstatscounter_formerr);
6178                         break;
6179                 default:
6180                         inc_stats(fctx->res, dns_resstatscounter_othererror);
6181                         break;
6182                 }
6183         }
6184
6185         /*
6186          * Is the remote server broken, or does it dislike us?
6187          */
6188         if (message->rcode != dns_rcode_noerror &&
6189             message->rcode != dns_rcode_nxdomain) {
6190                 if (((message->rcode == dns_rcode_formerr ||
6191                      message->rcode == dns_rcode_notimp) ||
6192                     (message->rcode == dns_rcode_servfail &&
6193                      dns_message_getopt(message) == NULL)) &&
6194                     (query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
6195                         /*
6196                          * It's very likely they don't like EDNS0.
6197                          * If the response code is SERVFAIL, also check if the
6198                          * response contains an OPT RR and don't cache the
6199                          * failure since it can be returned for various other
6200                          * reasons.
6201                          *
6202                          * XXXRTH  We should check if the question
6203                          *              we're asking requires EDNS0, and
6204                          *              if so, we should bail out.
6205                          */
6206                         options |= DNS_FETCHOPT_NOEDNS0;
6207                         resend = ISC_TRUE;
6208                         /*
6209                          * Remember that they don't like EDNS0.
6210                          */
6211                         if (message->rcode != dns_rcode_servfail)
6212                                 dns_adb_changeflags(fctx->adb, query->addrinfo,
6213                                                     DNS_FETCHOPT_NOEDNS0,
6214                                                     DNS_FETCHOPT_NOEDNS0);
6215                         inc_stats(fctx->res, dns_resstatscounter_edns0fail);
6216                 } else if (message->rcode == dns_rcode_formerr) {
6217                         if (ISFORWARDER(query->addrinfo)) {
6218                                 /*
6219                                  * This forwarder doesn't understand us,
6220                                  * but other forwarders might.  Keep trying.
6221                                  */
6222                                 broken_server = DNS_R_REMOTEFORMERR;
6223                                 keep_trying = ISC_TRUE;
6224                         } else {
6225                                 /*
6226                                  * The server doesn't understand us.  Since
6227                                  * all servers for a zone need similar
6228                                  * capabilities, we assume that we will get
6229                                  * FORMERR from all servers, and thus we
6230                                  * cannot make any more progress with this
6231                                  * fetch.
6232                                  */
6233                                 result = DNS_R_FORMERR;
6234                         }
6235                 } else if (message->rcode == dns_rcode_yxdomain) {
6236                         /*
6237                          * DNAME mapping failed because the new name
6238                          * was too long.  There's no chance of success
6239                          * for this fetch.
6240                          */
6241                         result = DNS_R_YXDOMAIN;
6242                 } else if (message->rcode == dns_rcode_badvers) {
6243                         unsigned int flags, mask;
6244                         unsigned int version;
6245
6246                         resend = ISC_TRUE;
6247                         version = (opt->ttl >> 16) & 0xff;
6248                         flags = (version << DNS_FETCHOPT_EDNSVERSIONSHIFT) |
6249                                 DNS_FETCHOPT_EDNSVERSIONSET;
6250                         mask = DNS_FETCHOPT_EDNSVERSIONMASK |
6251                                DNS_FETCHOPT_EDNSVERSIONSET;
6252                         switch (version) {
6253                         case 0:
6254                                 dns_adb_changeflags(fctx->adb, query->addrinfo,
6255                                                     flags, mask);
6256                                 break;
6257                         default:
6258                                 broken_server = DNS_R_BADVERS;
6259                                 keep_trying = ISC_TRUE;
6260                                 break;
6261                         }
6262                 } else {
6263                         /*
6264                          * XXXRTH log.
6265                          */
6266                         broken_server = DNS_R_UNEXPECTEDRCODE;
6267                         INSIST(broken_server != ISC_R_SUCCESS);
6268                         keep_trying = ISC_TRUE;
6269                 }
6270                 goto done;
6271         }
6272
6273         /*
6274          * Is the question the same as the one we asked?
6275          */
6276         result = same_question(fctx);
6277         if (result != ISC_R_SUCCESS) {
6278                 /* XXXRTH Log */
6279                 if (result == DNS_R_FORMERR)
6280                         keep_trying = ISC_TRUE;
6281                 goto done;
6282         }
6283
6284         /*
6285          * Is the server lame?
6286          */
6287         if (fctx->res->lame_ttl != 0 && !ISFORWARDER(query->addrinfo) &&
6288             is_lame(fctx)) {
6289                 inc_stats(fctx->res, dns_resstatscounter_lame);
6290                 log_lame(fctx, query->addrinfo);
6291                 result = dns_adb_marklame(fctx->adb, query->addrinfo,
6292                                           &fctx->name, fctx->type,
6293                                           now + fctx->res->lame_ttl);
6294                 if (result != ISC_R_SUCCESS)
6295                         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
6296                                       DNS_LOGMODULE_RESOLVER, ISC_LOG_ERROR,
6297                                       "could not mark server as lame: %s",
6298                                       isc_result_totext(result));
6299                 broken_server = DNS_R_LAME;
6300                 keep_trying = ISC_TRUE;
6301                 goto done;
6302         }
6303
6304         /*
6305          * Enforce delegations only zones like NET and COM.
6306          */
6307         if (!ISFORWARDER(query->addrinfo) &&
6308             dns_view_isdelegationonly(fctx->res->view, &fctx->domain) &&
6309             !dns_name_equal(&fctx->domain, &fctx->name) &&
6310             fix_mustbedelegationornxdomain(message, fctx)) {
6311                 char namebuf[DNS_NAME_FORMATSIZE];
6312                 char domainbuf[DNS_NAME_FORMATSIZE];
6313                 char addrbuf[ISC_SOCKADDR_FORMATSIZE];
6314                 char classbuf[64];
6315                 char typebuf[64];
6316
6317                 dns_name_format(&fctx->name, namebuf, sizeof(namebuf));
6318                 dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
6319                 dns_rdatatype_format(fctx->type, typebuf, sizeof(typebuf));
6320                 dns_rdataclass_format(fctx->res->rdclass, classbuf,
6321                                       sizeof(classbuf));
6322                 isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
6323                                     sizeof(addrbuf));
6324
6325                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_DELEGATION_ONLY,
6326                              DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
6327                              "enforced delegation-only for '%s' (%s/%s/%s) "
6328                              "from %s",
6329                              domainbuf, namebuf, typebuf, classbuf, addrbuf);
6330         }
6331
6332         if ((fctx->res->options & DNS_RESOLVER_CHECKNAMES) != 0)
6333                 checknames(message);
6334
6335         /*
6336          * Clear cache bits.
6337          */
6338         fctx->attributes &= ~(FCTX_ATTR_WANTNCACHE | FCTX_ATTR_WANTCACHE);
6339
6340         /*
6341          * Did we get any answers?
6342          */
6343         if (message->counts[DNS_SECTION_ANSWER] > 0 &&
6344             (message->rcode == dns_rcode_noerror ||
6345              message->rcode == dns_rcode_nxdomain)) {
6346                 /*
6347                  * We've got answers.  However, if we sent
6348                  * a BIND 8 server an NS query, it may have
6349                  * incorrectly responded with a non-authoritative
6350                  * answer instead of a referral.  Since this
6351                  * answer lacks the SIGs necessary to do DNSSEC
6352                  * validation, we must invoke the following special
6353                  * kludge to treat it as a referral.
6354                  */
6355                 if (fctx->type == dns_rdatatype_ns &&
6356                     (message->flags & DNS_MESSAGEFLAG_AA) == 0 &&
6357                     !ISFORWARDER(query->addrinfo))
6358                 {
6359                         result = noanswer_response(fctx, NULL, ISC_TRUE);
6360                         if (result != DNS_R_DELEGATION) {
6361                                 /*
6362                                  * The answer section must have contained
6363                                  * something other than the NS records
6364                                  * we asked for.  Since AA is not set
6365                                  * and the server is not a forwarder,
6366                                  * it is technically lame and it's easier
6367                                  * to treat it as such than to figure out
6368                                  * some more elaborate course of action.
6369                                  */
6370                                 broken_server = DNS_R_LAME;
6371                                 keep_trying = ISC_TRUE;
6372                                 goto done;
6373                         }
6374                         goto force_referral;
6375                 }
6376                 result = answer_response(fctx);
6377                 if (result != ISC_R_SUCCESS) {
6378                         if (result == DNS_R_FORMERR)
6379                                 keep_trying = ISC_TRUE;
6380                         goto done;
6381                 }
6382         } else if (message->counts[DNS_SECTION_AUTHORITY] > 0 ||
6383                    message->rcode == dns_rcode_noerror ||
6384                    message->rcode == dns_rcode_nxdomain) {
6385                 /*
6386                  * NXDOMAIN, NXRDATASET, or referral.
6387                  */
6388                 result = noanswer_response(fctx, NULL, ISC_FALSE);
6389                 if (result == DNS_R_CHASEDSSERVERS) {
6390                 } else if (result == DNS_R_DELEGATION) {
6391                 force_referral:
6392                         /*
6393                          * We don't have the answer, but we know a better
6394                          * place to look.
6395                          */
6396                         get_nameservers = ISC_TRUE;
6397                         keep_trying = ISC_TRUE;
6398                         /*
6399                          * We have a new set of name servers, and it
6400                          * has not experienced any restarts yet.
6401                          */
6402                         fctx->restarts = 0;
6403
6404                         /*
6405                          * Update local statistics counters collected for each
6406                          * new zone.
6407                          */
6408                         fctx->referrals++;
6409                         fctx->querysent = 0;
6410                         fctx->lamecount = 0;
6411                         fctx->neterr = 0;
6412                         fctx->badresp = 0;
6413                         fctx->adberr = 0;
6414
6415                         result = ISC_R_SUCCESS;
6416                 } else if (result != ISC_R_SUCCESS) {
6417                         /*
6418                          * Something has gone wrong.
6419                          */
6420                         if (result == DNS_R_FORMERR)
6421                                 keep_trying = ISC_TRUE;
6422                         goto done;
6423                 }
6424         } else {
6425                 /*
6426                  * The server is insane.
6427                  */
6428                 /* XXXRTH Log */
6429                 broken_server = DNS_R_UNEXPECTEDRCODE;
6430                 keep_trying = ISC_TRUE;
6431                 goto done;
6432         }
6433
6434         /*
6435          * Follow additional section data chains.
6436          */
6437         chase_additional(fctx);
6438
6439         /*
6440          * Cache the cacheable parts of the message.  This may also cause
6441          * work to be queued to the DNSSEC validator.
6442          */
6443         if (WANTCACHE(fctx)) {
6444                 result = cache_message(fctx, query->addrinfo, now);
6445                 if (result != ISC_R_SUCCESS)
6446                         goto done;
6447         }
6448
6449         /*
6450          * Ncache the negatively cacheable parts of the message.  This may
6451          * also cause work to be queued to the DNSSEC validator.
6452          */
6453         if (WANTNCACHE(fctx)) {
6454                 dns_rdatatype_t covers;
6455                 if (message->rcode == dns_rcode_nxdomain)
6456                         covers = dns_rdatatype_any;
6457                 else
6458                         covers = fctx->type;
6459
6460                 /*
6461                  * Cache any negative cache entries in the message.
6462                  */
6463                 result = ncache_message(fctx, query->addrinfo, covers, now);
6464         }
6465
6466  done:
6467         /*
6468          * Remember the query's addrinfo, in case we need to mark the
6469          * server as broken.
6470          */
6471         addrinfo = query->addrinfo;
6472
6473         /*
6474          * Cancel the query.
6475          *
6476          * XXXRTH  Don't cancel the query if waiting for validation?
6477          */
6478         fctx_cancelquery(&query, &devent, finish, ISC_FALSE);
6479
6480         if (keep_trying) {
6481                 if (result == DNS_R_FORMERR)
6482                         broken_server = DNS_R_FORMERR;
6483                 if (broken_server != ISC_R_SUCCESS) {
6484                         /*
6485                          * Add this server to the list of bad servers for
6486                          * this fctx.
6487                          */
6488                         add_bad(fctx, addrinfo, broken_server, broken_type);
6489                 }
6490
6491                 if (get_nameservers) {
6492                         dns_name_t *name;
6493                         dns_fixedname_init(&foundname);
6494                         fname = dns_fixedname_name(&foundname);
6495                         if (result != ISC_R_SUCCESS) {
6496                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6497                                 return;
6498                         }
6499                         findoptions = 0;
6500                         if (dns_rdatatype_atparent(fctx->type))
6501                                 findoptions |= DNS_DBFIND_NOEXACT;
6502                         if ((options & DNS_FETCHOPT_UNSHARED) == 0)
6503                                 name = &fctx->name;
6504                         else
6505                                 name = &fctx->domain;
6506                         result = dns_view_findzonecut(fctx->res->view,
6507                                                       name, fname,
6508                                                       now, findoptions,
6509                                                       ISC_TRUE,
6510                                                       &fctx->nameservers,
6511                                                       NULL);
6512                         if (result != ISC_R_SUCCESS) {
6513                                 FCTXTRACE("couldn't find a zonecut");
6514                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6515                                 return;
6516                         }
6517                         if (!dns_name_issubdomain(fname, &fctx->domain)) {
6518                                 /*
6519                                  * The best nameservers are now above our
6520                                  * QDOMAIN.
6521                                  */
6522                                 FCTXTRACE("nameservers now above QDOMAIN");
6523                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6524                                 return;
6525                         }
6526                         dns_name_free(&fctx->domain,
6527                                       fctx->res->buckets[fctx->bucketnum].mctx);
6528                         dns_name_init(&fctx->domain, NULL);
6529                         result = dns_name_dup(fname,
6530                                               fctx->res->buckets[fctx->bucketnum].mctx,
6531                                               &fctx->domain);
6532                         if (result != ISC_R_SUCCESS) {
6533                                 fctx_done(fctx, DNS_R_SERVFAIL, __LINE__);
6534                                 return;
6535                         }
6536                         fctx_cancelqueries(fctx, ISC_TRUE);
6537                         fctx_cleanupfinds(fctx);
6538                         fctx_cleanupaltfinds(fctx);
6539                         fctx_cleanupforwaddrs(fctx);
6540                         fctx_cleanupaltaddrs(fctx);
6541                 }
6542                 /*
6543                  * Try again.
6544                  */
6545                 fctx_try(fctx, !get_nameservers);
6546         } else if (resend) {
6547                 /*
6548                  * Resend (probably with changed options).
6549                  */
6550                 FCTXTRACE("resend");
6551                 inc_stats(fctx->res, dns_resstatscounter_retry);
6552                 result = fctx_query(fctx, addrinfo, options);
6553                 if (result != ISC_R_SUCCESS)
6554                         fctx_done(fctx, result, __LINE__);
6555         } else if (result == ISC_R_SUCCESS && !HAVE_ANSWER(fctx)) {
6556                 /*
6557                  * All has gone well so far, but we are waiting for the
6558                  * DNSSEC validator to validate the answer.
6559                  */
6560                 FCTXTRACE("wait for validator");
6561                 fctx_cancelqueries(fctx, ISC_TRUE);
6562                 /*
6563                  * We must not retransmit while the validator is working;
6564                  * it has references to the current rmessage.
6565                  */
6566                 result = fctx_stopidletimer(fctx);
6567                 if (result != ISC_R_SUCCESS)
6568                         fctx_done(fctx, result, __LINE__);
6569         } else if (result == DNS_R_CHASEDSSERVERS) {
6570                 unsigned int n;
6571                 add_bad(fctx, addrinfo, result, broken_type);
6572                 fctx_cancelqueries(fctx, ISC_TRUE);
6573                 fctx_cleanupfinds(fctx);
6574                 fctx_cleanupforwaddrs(fctx);
6575
6576                 n = dns_name_countlabels(&fctx->name);
6577                 dns_name_getlabelsequence(&fctx->name, 1, n - 1, &fctx->nsname);
6578
6579                 FCTXTRACE("suspending DS lookup to find parent's NS records");
6580
6581                 result = dns_resolver_createfetch(fctx->res, &fctx->nsname,
6582                                                   dns_rdatatype_ns,
6583                                                   NULL, NULL, NULL, 0, task,
6584                                                   resume_dslookup, fctx,
6585                                                   &fctx->nsrrset, NULL,
6586                                                   &fctx->nsfetch);
6587                 if (result != ISC_R_SUCCESS)
6588                         fctx_done(fctx, result, __LINE__);
6589                 LOCK(&fctx->res->buckets[fctx->bucketnum].lock);
6590                 fctx->references++;
6591                 UNLOCK(&fctx->res->buckets[fctx->bucketnum].lock);
6592                 result = fctx_stopidletimer(fctx);
6593                 if (result != ISC_R_SUCCESS)
6594                         fctx_done(fctx, result, __LINE__);
6595         } else {
6596                 /*
6597                  * We're done.
6598                  */
6599                 fctx_done(fctx, result, __LINE__);
6600         }
6601 }
6602
6603
6604 /***
6605  *** Resolver Methods
6606  ***/
6607
6608 static void
6609 destroy(dns_resolver_t *res) {
6610         unsigned int i;
6611         alternate_t *a;
6612
6613         REQUIRE(res->references == 0);
6614         REQUIRE(!res->priming);
6615         REQUIRE(res->primefetch == NULL);
6616
6617         RTRACE("destroy");
6618
6619         INSIST(res->nfctx == 0);
6620
6621         DESTROYLOCK(&res->primelock);
6622         DESTROYLOCK(&res->nlock);
6623         DESTROYLOCK(&res->lock);
6624         for (i = 0; i < res->nbuckets; i++) {
6625                 INSIST(ISC_LIST_EMPTY(res->buckets[i].fctxs));
6626                 isc_task_shutdown(res->buckets[i].task);
6627                 isc_task_detach(&res->buckets[i].task);
6628                 DESTROYLOCK(&res->buckets[i].lock);
6629                 isc_mem_detach(&res->buckets[i].mctx);
6630         }
6631         isc_mem_put(res->mctx, res->buckets,
6632                     res->nbuckets * sizeof(fctxbucket_t));
6633         if (res->dispatchv4 != NULL)
6634                 dns_dispatch_detach(&res->dispatchv4);
6635         if (res->dispatchv6 != NULL)
6636                 dns_dispatch_detach(&res->dispatchv6);
6637         while ((a = ISC_LIST_HEAD(res->alternates)) != NULL) {
6638                 ISC_LIST_UNLINK(res->alternates, a, link);
6639                 if (!a->isaddress)
6640                         dns_name_free(&a->_u._n.name, res->mctx);
6641                 isc_mem_put(res->mctx, a, sizeof(*a));
6642         }
6643         dns_resolver_reset_algorithms(res);
6644         dns_resolver_resetmustbesecure(res);
6645 #if USE_ALGLOCK
6646         isc_rwlock_destroy(&res->alglock);
6647 #endif
6648 #if USE_MBSLOCK
6649         isc_rwlock_destroy(&res->mbslock);
6650 #endif
6651         isc_timer_detach(&res->spillattimer);
6652         res->magic = 0;
6653         isc_mem_put(res->mctx, res, sizeof(*res));
6654 }
6655
6656 static void
6657 send_shutdown_events(dns_resolver_t *res) {
6658         isc_event_t *event, *next_event;
6659         isc_task_t *etask;
6660
6661         /*
6662          * Caller must be holding the resolver lock.
6663          */
6664
6665         for (event = ISC_LIST_HEAD(res->whenshutdown);
6666              event != NULL;
6667              event = next_event) {
6668                 next_event = ISC_LIST_NEXT(event, ev_link);
6669                 ISC_LIST_UNLINK(res->whenshutdown, event, ev_link);
6670                 etask = event->ev_sender;
6671                 event->ev_sender = res;
6672                 isc_task_sendanddetach(&etask, &event);
6673         }
6674 }
6675
6676 static void
6677 empty_bucket(dns_resolver_t *res) {
6678         RTRACE("empty_bucket");
6679
6680         LOCK(&res->lock);
6681
6682         INSIST(res->activebuckets > 0);
6683         res->activebuckets--;
6684         if (res->activebuckets == 0)
6685                 send_shutdown_events(res);
6686
6687         UNLOCK(&res->lock);
6688 }
6689
6690 static void
6691 spillattimer_countdown(isc_task_t *task, isc_event_t *event) {
6692         dns_resolver_t *res = event->ev_arg;
6693         isc_result_t result;
6694         unsigned int count;
6695         isc_boolean_t logit = ISC_FALSE;
6696
6697         REQUIRE(VALID_RESOLVER(res));
6698
6699         UNUSED(task);
6700
6701         LOCK(&res->lock);
6702         INSIST(!res->exiting);
6703         if (res->spillat > res->spillatmin) {
6704                 res->spillat--;
6705                 logit = ISC_TRUE;
6706         }
6707         if (res->spillat <= res->spillatmin) {
6708                 result = isc_timer_reset(res->spillattimer,
6709                                          isc_timertype_inactive, NULL,
6710                                          NULL, ISC_TRUE);
6711                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
6712         }
6713         count = res->spillat;
6714         UNLOCK(&res->lock);
6715         if (logit)
6716                 isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
6717                               DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
6718                               "clients-per-query decreased to %u", count);
6719
6720         isc_event_free(&event);
6721 }
6722
6723 isc_result_t
6724 dns_resolver_create(dns_view_t *view,
6725                     isc_taskmgr_t *taskmgr, unsigned int ntasks,
6726                     isc_socketmgr_t *socketmgr,
6727                     isc_timermgr_t *timermgr,
6728                     unsigned int options,
6729                     dns_dispatchmgr_t *dispatchmgr,
6730                     dns_dispatch_t *dispatchv4,
6731                     dns_dispatch_t *dispatchv6,
6732                     dns_resolver_t **resp)
6733 {
6734         dns_resolver_t *res;
6735         isc_result_t result = ISC_R_SUCCESS;
6736         unsigned int i, buckets_created = 0;
6737         isc_task_t *task = NULL;
6738         char name[16];
6739         unsigned dispattr;
6740
6741         /*
6742          * Create a resolver.
6743          */
6744
6745         REQUIRE(DNS_VIEW_VALID(view));
6746         REQUIRE(ntasks > 0);
6747         REQUIRE(resp != NULL && *resp == NULL);
6748         REQUIRE(dispatchmgr != NULL);
6749         REQUIRE(dispatchv4 != NULL || dispatchv6 != NULL);
6750
6751         res = isc_mem_get(view->mctx, sizeof(*res));
6752         if (res == NULL)
6753                 return (ISC_R_NOMEMORY);
6754         RTRACE("create");
6755         res->mctx = view->mctx;
6756         res->rdclass = view->rdclass;
6757         res->socketmgr = socketmgr;
6758         res->timermgr = timermgr;
6759         res->taskmgr = taskmgr;
6760         res->dispatchmgr = dispatchmgr;
6761         res->view = view;
6762         res->options = options;
6763         res->lame_ttl = 0;
6764         ISC_LIST_INIT(res->alternates);
6765         res->udpsize = RECV_BUFFER_SIZE;
6766         res->algorithms = NULL;
6767         res->mustbesecure = NULL;
6768         res->spillatmin = res->spillat = 10;
6769         res->spillatmax = 100;
6770         res->spillattimer = NULL;
6771         res->zero_no_soa_ttl = ISC_FALSE;
6772         res->ndisps = 0;
6773         res->nextdisp = 0; /* meaningless at this point, but init it */
6774         res->nbuckets = ntasks;
6775         res->activebuckets = ntasks;
6776         res->buckets = isc_mem_get(view->mctx,
6777                                    ntasks * sizeof(fctxbucket_t));
6778         if (res->buckets == NULL) {
6779                 result = ISC_R_NOMEMORY;
6780                 goto cleanup_res;
6781         }
6782         for (i = 0; i < ntasks; i++) {
6783                 result = isc_mutex_init(&res->buckets[i].lock);
6784                 if (result != ISC_R_SUCCESS)
6785                         goto cleanup_buckets;
6786                 res->buckets[i].task = NULL;
6787                 result = isc_task_create(taskmgr, 0, &res->buckets[i].task);
6788                 if (result != ISC_R_SUCCESS) {
6789                         DESTROYLOCK(&res->buckets[i].lock);
6790                         goto cleanup_buckets;
6791                 }
6792                 res->buckets[i].mctx = NULL;
6793                 snprintf(name, sizeof(name), "res%u", i);
6794 #ifdef ISC_PLATFORM_USETHREADS
6795                 /*
6796                  * Use a separate memory context for each bucket to reduce
6797                  * contention among multiple threads.  Do this only when
6798                  * enabling threads because it will be require more memory.
6799                  */
6800                 result = isc_mem_create(0, 0, &res->buckets[i].mctx);
6801                 if (result != ISC_R_SUCCESS) {
6802                         isc_task_detach(&res->buckets[i].task);
6803                         DESTROYLOCK(&res->buckets[i].lock);
6804                         goto cleanup_buckets;
6805                 }
6806                 isc_mem_setname(res->buckets[i].mctx, name, NULL);
6807 #else
6808                 isc_mem_attach(view->mctx, &res->buckets[i].mctx);
6809 #endif
6810                 isc_task_setname(res->buckets[i].task, name, res);
6811                 ISC_LIST_INIT(res->buckets[i].fctxs);
6812                 res->buckets[i].exiting = ISC_FALSE;
6813                 buckets_created++;
6814         }
6815
6816         res->dispatchv4 = NULL;
6817         if (dispatchv4 != NULL) {
6818                 dns_dispatch_attach(dispatchv4, &res->dispatchv4);
6819                 dispattr = dns_dispatch_getattributes(dispatchv4);
6820                 res->exclusivev4 =
6821                         ISC_TF((dispattr & DNS_DISPATCHATTR_EXCLUSIVE) != 0);
6822         }
6823
6824         res->dispatchv6 = NULL;
6825         if (dispatchv6 != NULL) {
6826                 dns_dispatch_attach(dispatchv6, &res->dispatchv6);
6827                 dispattr = dns_dispatch_getattributes(dispatchv6);
6828                 res->exclusivev6 =
6829                         ISC_TF((dispattr & DNS_DISPATCHATTR_EXCLUSIVE) != 0);
6830         }
6831
6832         res->references = 1;
6833         res->exiting = ISC_FALSE;
6834         res->frozen = ISC_FALSE;
6835         ISC_LIST_INIT(res->whenshutdown);
6836         res->priming = ISC_FALSE;
6837         res->primefetch = NULL;
6838         res->nfctx = 0;
6839
6840         result = isc_mutex_init(&res->lock);
6841         if (result != ISC_R_SUCCESS)
6842                 goto cleanup_dispatches;
6843
6844         result = isc_mutex_init(&res->nlock);
6845         if (result != ISC_R_SUCCESS)
6846                 goto cleanup_lock;
6847
6848         result = isc_mutex_init(&res->primelock);
6849         if (result != ISC_R_SUCCESS)
6850                 goto cleanup_nlock;
6851
6852         task = NULL;
6853         result = isc_task_create(taskmgr, 0, &task);
6854         if (result != ISC_R_SUCCESS)
6855                 goto cleanup_primelock;
6856
6857         result = isc_timer_create(timermgr, isc_timertype_inactive, NULL, NULL,
6858                                   task, spillattimer_countdown, res,
6859                                   &res->spillattimer);
6860         isc_task_detach(&task);
6861         if (result != ISC_R_SUCCESS)
6862                 goto cleanup_primelock;
6863
6864 #if USE_ALGLOCK
6865         result = isc_rwlock_init(&res->alglock, 0, 0);
6866         if (result != ISC_R_SUCCESS)
6867                 goto cleanup_spillattimer;
6868 #endif
6869 #if USE_MBSLOCK
6870         result = isc_rwlock_init(&res->mbslock, 0, 0);
6871         if (result != ISC_R_SUCCESS)
6872                 goto cleanup_alglock;
6873 #endif
6874
6875         res->magic = RES_MAGIC;
6876
6877         *resp = res;
6878
6879         return (ISC_R_SUCCESS);
6880
6881 #if USE_MBSLOCK
6882  cleanup_alglock:
6883 #if USE_ALGLOCK
6884         isc_rwlock_destroy(&res->alglock);
6885 #endif
6886 #endif
6887 #if USE_ALGLOCK || USE_MBSLOCK
6888  cleanup_spillattimer:
6889         isc_timer_detach(&res->spillattimer);
6890 #endif
6891
6892  cleanup_primelock:
6893         DESTROYLOCK(&res->primelock);
6894
6895  cleanup_nlock:
6896         DESTROYLOCK(&res->nlock);
6897
6898  cleanup_lock:
6899         DESTROYLOCK(&res->lock);
6900
6901  cleanup_dispatches:
6902         if (res->dispatchv6 != NULL)
6903                 dns_dispatch_detach(&res->dispatchv6);
6904         if (res->dispatchv4 != NULL)
6905                 dns_dispatch_detach(&res->dispatchv4);
6906
6907  cleanup_buckets:
6908         for (i = 0; i < buckets_created; i++) {
6909                 isc_mem_detach(&res->buckets[i].mctx);
6910                 DESTROYLOCK(&res->buckets[i].lock);
6911                 isc_task_shutdown(res->buckets[i].task);
6912                 isc_task_detach(&res->buckets[i].task);
6913         }
6914         isc_mem_put(view->mctx, res->buckets,
6915                     res->nbuckets * sizeof(fctxbucket_t));
6916
6917  cleanup_res:
6918         isc_mem_put(view->mctx, res, sizeof(*res));
6919
6920         return (result);
6921 }
6922
6923 static void
6924 prime_done(isc_task_t *task, isc_event_t *event) {
6925         dns_resolver_t *res;
6926         dns_fetchevent_t *fevent;
6927         dns_fetch_t *fetch;
6928         dns_db_t *db = NULL;
6929
6930         REQUIRE(event->ev_type == DNS_EVENT_FETCHDONE);
6931         fevent = (dns_fetchevent_t *)event;
6932         res = event->ev_arg;
6933         REQUIRE(VALID_RESOLVER(res));
6934
6935         UNUSED(task);
6936
6937         LOCK(&res->lock);
6938
6939         INSIST(res->priming);
6940         res->priming = ISC_FALSE;
6941         LOCK(&res->primelock);
6942         fetch = res->primefetch;
6943         res->primefetch = NULL;
6944         UNLOCK(&res->primelock);
6945
6946         UNLOCK(&res->lock);
6947
6948         if (fevent->result == ISC_R_SUCCESS &&
6949             res->view->cache != NULL && res->view->hints != NULL) {
6950                 dns_cache_attachdb(res->view->cache, &db);
6951                 dns_root_checkhints(res->view, res->view->hints, db);
6952                 dns_db_detach(&db);
6953         }
6954
6955         if (fevent->node != NULL)
6956                 dns_db_detachnode(fevent->db, &fevent->node);
6957         if (fevent->db != NULL)
6958                 dns_db_detach(&fevent->db);
6959         if (dns_rdataset_isassociated(fevent->rdataset))
6960                 dns_rdataset_disassociate(fevent->rdataset);
6961         INSIST(fevent->sigrdataset == NULL);
6962
6963         isc_mem_put(res->mctx, fevent->rdataset, sizeof(*fevent->rdataset));
6964
6965         isc_event_free(&event);
6966         dns_resolver_destroyfetch(&fetch);
6967 }
6968
6969 void
6970 dns_resolver_prime(dns_resolver_t *res) {
6971         isc_boolean_t want_priming = ISC_FALSE;
6972         dns_rdataset_t *rdataset;
6973         isc_result_t result;
6974
6975         REQUIRE(VALID_RESOLVER(res));
6976         REQUIRE(res->frozen);
6977
6978         RTRACE("dns_resolver_prime");
6979
6980         LOCK(&res->lock);
6981
6982         if (!res->exiting && !res->priming) {
6983                 INSIST(res->primefetch == NULL);
6984                 res->priming = ISC_TRUE;
6985                 want_priming = ISC_TRUE;
6986         }
6987
6988         UNLOCK(&res->lock);
6989
6990         if (want_priming) {
6991                 /*
6992                  * To avoid any possible recursive locking problems, we
6993                  * start the priming fetch like any other fetch, and holding
6994                  * no resolver locks.  No one else will try to start it
6995                  * because we're the ones who set res->priming to true.
6996                  * Any other callers of dns_resolver_prime() while we're
6997                  * running will see that res->priming is already true and
6998                  * do nothing.
6999                  */
7000                 RTRACE("priming");
7001                 rdataset = isc_mem_get(res->mctx, sizeof(*rdataset));
7002                 if (rdataset == NULL) {
7003                         LOCK(&res->lock);
7004                         INSIST(res->priming);
7005                         INSIST(res->primefetch == NULL);
7006                         res->priming = ISC_FALSE;
7007                         UNLOCK(&res->lock);
7008                         return;
7009                 }
7010                 dns_rdataset_init(rdataset);
7011                 LOCK(&res->primelock);
7012                 result = dns_resolver_createfetch(res, dns_rootname,
7013                                                   dns_rdatatype_ns,
7014                                                   NULL, NULL, NULL, 0,
7015                                                   res->buckets[0].task,
7016                                                   prime_done,
7017                                                   res, rdataset, NULL,
7018                                                   &res->primefetch);
7019                 UNLOCK(&res->primelock);
7020                 if (result != ISC_R_SUCCESS) {
7021                         LOCK(&res->lock);
7022                         INSIST(res->priming);
7023                         res->priming = ISC_FALSE;
7024                         UNLOCK(&res->lock);
7025                 }
7026         }
7027 }
7028
7029 void
7030 dns_resolver_freeze(dns_resolver_t *res) {
7031
7032         /*
7033          * Freeze resolver.
7034          */
7035
7036         REQUIRE(VALID_RESOLVER(res));
7037         REQUIRE(!res->frozen);
7038
7039         res->frozen = ISC_TRUE;
7040 }
7041
7042 void
7043 dns_resolver_attach(dns_resolver_t *source, dns_resolver_t **targetp) {
7044         REQUIRE(VALID_RESOLVER(source));
7045         REQUIRE(targetp != NULL && *targetp == NULL);
7046
7047         RRTRACE(source, "attach");
7048         LOCK(&source->lock);
7049         REQUIRE(!source->exiting);
7050
7051         INSIST(source->references > 0);
7052         source->references++;
7053         INSIST(source->references != 0);
7054         UNLOCK(&source->lock);
7055
7056         *targetp = source;
7057 }
7058
7059 void
7060 dns_resolver_whenshutdown(dns_resolver_t *res, isc_task_t *task,
7061                           isc_event_t **eventp)
7062 {
7063         isc_task_t *clone;
7064         isc_event_t *event;
7065
7066         REQUIRE(VALID_RESOLVER(res));
7067         REQUIRE(eventp != NULL);
7068
7069         event = *eventp;
7070         *eventp = NULL;
7071
7072         LOCK(&res->lock);
7073
7074         if (res->exiting && res->activebuckets == 0) {
7075                 /*
7076                  * We're already shutdown.  Send the event.
7077                  */
7078                 event->ev_sender = res;
7079                 isc_task_send(task, &event);
7080         } else {
7081                 clone = NULL;
7082                 isc_task_attach(task, &clone);
7083                 event->ev_sender = clone;
7084                 ISC_LIST_APPEND(res->whenshutdown, event, ev_link);
7085         }
7086
7087         UNLOCK(&res->lock);
7088 }
7089
7090 void
7091 dns_resolver_shutdown(dns_resolver_t *res) {
7092         unsigned int i;
7093         fetchctx_t *fctx;
7094         isc_socket_t *sock;
7095         isc_result_t result;
7096
7097         REQUIRE(VALID_RESOLVER(res));
7098
7099         RTRACE("shutdown");
7100
7101         LOCK(&res->lock);
7102
7103         if (!res->exiting) {
7104                 RTRACE("exiting");
7105                 res->exiting = ISC_TRUE;
7106
7107                 for (i = 0; i < res->nbuckets; i++) {
7108                         LOCK(&res->buckets[i].lock);
7109                         for (fctx = ISC_LIST_HEAD(res->buckets[i].fctxs);
7110                              fctx != NULL;
7111                              fctx = ISC_LIST_NEXT(fctx, link))
7112                                 fctx_shutdown(fctx);
7113                         if (res->dispatchv4 != NULL && !res->exclusivev4) {
7114                                 sock = dns_dispatch_getsocket(res->dispatchv4);
7115                                 isc_socket_cancel(sock, res->buckets[i].task,
7116                                                   ISC_SOCKCANCEL_ALL);
7117                         }
7118                         if (res->dispatchv6 != NULL && !res->exclusivev6) {
7119                                 sock = dns_dispatch_getsocket(res->dispatchv6);
7120                                 isc_socket_cancel(sock, res->buckets[i].task,
7121                                                   ISC_SOCKCANCEL_ALL);
7122                         }
7123                         res->buckets[i].exiting = ISC_TRUE;
7124                         if (ISC_LIST_EMPTY(res->buckets[i].fctxs)) {
7125                                 INSIST(res->activebuckets > 0);
7126                                 res->activebuckets--;
7127                         }
7128                         UNLOCK(&res->buckets[i].lock);
7129                 }
7130                 if (res->activebuckets == 0)
7131                         send_shutdown_events(res);
7132                 result = isc_timer_reset(res->spillattimer,
7133                                          isc_timertype_inactive, NULL,
7134                                          NULL, ISC_TRUE);
7135                 RUNTIME_CHECK(result == ISC_R_SUCCESS);
7136         }
7137
7138         UNLOCK(&res->lock);
7139 }
7140
7141 void
7142 dns_resolver_detach(dns_resolver_t **resp) {
7143         dns_resolver_t *res;
7144         isc_boolean_t need_destroy = ISC_FALSE;
7145
7146         REQUIRE(resp != NULL);
7147         res = *resp;
7148         REQUIRE(VALID_RESOLVER(res));
7149
7150         RTRACE("detach");
7151
7152         LOCK(&res->lock);
7153
7154         INSIST(res->references > 0);
7155         res->references--;
7156         if (res->references == 0) {
7157                 INSIST(res->exiting && res->activebuckets == 0);
7158                 need_destroy = ISC_TRUE;
7159         }
7160
7161         UNLOCK(&res->lock);
7162
7163         if (need_destroy)
7164                 destroy(res);
7165
7166         *resp = NULL;
7167 }
7168
7169 static inline isc_boolean_t
7170 fctx_match(fetchctx_t *fctx, dns_name_t *name, dns_rdatatype_t type,
7171            unsigned int options)
7172 {
7173         if (fctx->type != type || fctx->options != options)
7174                 return (ISC_FALSE);
7175         return (dns_name_equal(&fctx->name, name));
7176 }
7177
7178 static inline void
7179 log_fetch(dns_name_t *name, dns_rdatatype_t type) {
7180         char namebuf[DNS_NAME_FORMATSIZE];
7181         char typebuf[DNS_RDATATYPE_FORMATSIZE];
7182         int level = ISC_LOG_DEBUG(1);
7183
7184         if (! isc_log_wouldlog(dns_lctx, level))
7185                 return;
7186
7187         dns_name_format(name, namebuf, sizeof(namebuf));
7188         dns_rdatatype_format(type, typebuf, sizeof(typebuf));
7189
7190         isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
7191                       DNS_LOGMODULE_RESOLVER, level,
7192                       "createfetch: %s %s", namebuf, typebuf);
7193 }
7194
7195 isc_result_t
7196 dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
7197                          dns_rdatatype_t type,
7198                          dns_name_t *domain, dns_rdataset_t *nameservers,
7199                          dns_forwarders_t *forwarders,
7200                          unsigned int options, isc_task_t *task,
7201                          isc_taskaction_t action, void *arg,
7202                          dns_rdataset_t *rdataset,
7203                          dns_rdataset_t *sigrdataset,
7204                          dns_fetch_t **fetchp)
7205 {
7206         return (dns_resolver_createfetch2(res, name, type, domain,
7207                                           nameservers, forwarders, NULL, 0,
7208                                           options, task, action, arg,
7209                                           rdataset, sigrdataset, fetchp));
7210 }
7211
7212 isc_result_t
7213 dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name,
7214                           dns_rdatatype_t type,
7215                           dns_name_t *domain, dns_rdataset_t *nameservers,
7216                           dns_forwarders_t *forwarders,
7217                           isc_sockaddr_t *client, dns_messageid_t id,
7218                           unsigned int options, isc_task_t *task,
7219                           isc_taskaction_t action, void *arg,
7220                           dns_rdataset_t *rdataset,
7221                           dns_rdataset_t *sigrdataset,
7222                           dns_fetch_t **fetchp)
7223 {
7224         dns_fetch_t *fetch;
7225         fetchctx_t *fctx = NULL;
7226         isc_result_t result = ISC_R_SUCCESS;
7227         unsigned int bucketnum;
7228         isc_boolean_t new_fctx = ISC_FALSE;
7229         isc_event_t *event;
7230         unsigned int count = 0;
7231         unsigned int spillat;
7232         unsigned int spillatmin;
7233
7234         UNUSED(forwarders);
7235
7236         REQUIRE(VALID_RESOLVER(res));
7237         REQUIRE(res->frozen);
7238         /* XXXRTH  Check for meta type */
7239         if (domain != NULL) {
7240                 REQUIRE(DNS_RDATASET_VALID(nameservers));
7241                 REQUIRE(nameservers->type == dns_rdatatype_ns);
7242         } else
7243                 REQUIRE(nameservers == NULL);
7244         REQUIRE(forwarders == NULL);
7245         REQUIRE(!dns_rdataset_isassociated(rdataset));
7246         REQUIRE(sigrdataset == NULL ||
7247                 !dns_rdataset_isassociated(sigrdataset));
7248         REQUIRE(fetchp != NULL && *fetchp == NULL);
7249
7250         log_fetch(name, type);
7251
7252         /*
7253          * XXXRTH  use a mempool?
7254          */
7255         fetch = isc_mem_get(res->mctx, sizeof(*fetch));
7256         if (fetch == NULL)
7257                 return (ISC_R_NOMEMORY);
7258
7259         bucketnum = dns_name_fullhash(name, ISC_FALSE) % res->nbuckets;
7260
7261         LOCK(&res->lock);
7262         spillat = res->spillat;
7263         spillatmin = res->spillatmin;
7264         UNLOCK(&res->lock);
7265         LOCK(&res->buckets[bucketnum].lock);
7266
7267         if (res->buckets[bucketnum].exiting) {
7268                 result = ISC_R_SHUTTINGDOWN;
7269                 goto unlock;
7270         }
7271
7272         if ((options & DNS_FETCHOPT_UNSHARED) == 0) {
7273                 for (fctx = ISC_LIST_HEAD(res->buckets[bucketnum].fctxs);
7274                      fctx != NULL;
7275                      fctx = ISC_LIST_NEXT(fctx, link)) {
7276                         if (fctx_match(fctx, name, type, options))
7277                                 break;
7278                 }
7279         }
7280
7281         /*
7282          * Is this a duplicate?
7283          */
7284         if (fctx != NULL && client != NULL) {
7285                 dns_fetchevent_t *fevent;
7286                 for (fevent = ISC_LIST_HEAD(fctx->events);
7287                      fevent != NULL;
7288                      fevent = ISC_LIST_NEXT(fevent, ev_link)) {
7289                         if (fevent->client != NULL && fevent->id == id &&
7290                             isc_sockaddr_equal(fevent->client, client)) {
7291                                 result = DNS_R_DUPLICATE;
7292                                 goto unlock;
7293                         }
7294                         count++;
7295                 }
7296         }
7297         if (count >= spillatmin && spillatmin != 0) {
7298                 INSIST(fctx != NULL);
7299                 if (count >= spillat)
7300                         fctx->spilled = ISC_TRUE;
7301                 if (fctx->spilled) {
7302                         result = DNS_R_DROP;
7303                         goto unlock;
7304                 }
7305         }
7306
7307         /*
7308          * If we didn't have a fetch, would attach to a done fetch, this
7309          * fetch has already cloned its results, or if the fetch has gone
7310          * "idle" (no one was interested in it), we need to start a new
7311          * fetch instead of joining with the existing one.
7312          */
7313         if (fctx == NULL ||
7314             fctx->state == fetchstate_done ||
7315             fctx->cloned ||
7316             ISC_LIST_EMPTY(fctx->events)) {
7317                 fctx = NULL;
7318                 result = fctx_create(res, name, type, domain, nameservers,
7319                                      options, bucketnum, &fctx);
7320                 if (result != ISC_R_SUCCESS)
7321                         goto unlock;
7322                 new_fctx = ISC_TRUE;
7323         }
7324
7325         result = fctx_join(fctx, task, client, id, action, arg,
7326                            rdataset, sigrdataset, fetch);
7327         if (new_fctx) {
7328                 if (result == ISC_R_SUCCESS) {
7329                         /*
7330                          * Launch this fctx.
7331                          */
7332                         event = &fctx->control_event;
7333                         ISC_EVENT_INIT(event, sizeof(*event), 0, NULL,
7334                                        DNS_EVENT_FETCHCONTROL,
7335                                        fctx_start, fctx, NULL,
7336                                        NULL, NULL);
7337                         isc_task_send(res->buckets[bucketnum].task, &event);
7338                 } else {
7339                         /*
7340                          * We don't care about the result of fctx_destroy()
7341                          * since we know we're not exiting.
7342                          */
7343                         (void)fctx_destroy(fctx);
7344                 }
7345         }
7346
7347  unlock:
7348         UNLOCK(&res->buckets[bucketnum].lock);
7349
7350         if (result == ISC_R_SUCCESS) {
7351                 FTRACE("created");
7352                 *fetchp = fetch;
7353         } else
7354                 isc_mem_put(res->mctx, fetch, sizeof(*fetch));
7355
7356         return (result);
7357 }
7358
7359 void
7360 dns_resolver_cancelfetch(dns_fetch_t *fetch) {
7361         fetchctx_t *fctx;
7362         dns_resolver_t *res;
7363         dns_fetchevent_t *event, *next_event;
7364         isc_task_t *etask;
7365
7366         REQUIRE(DNS_FETCH_VALID(fetch));
7367         fctx = fetch->private;
7368         REQUIRE(VALID_FCTX(fctx));
7369         res = fctx->res;
7370
7371         FTRACE("cancelfetch");
7372
7373         LOCK(&res->buckets[fctx->bucketnum].lock);
7374
7375         /*
7376          * Find the completion event for this fetch (as opposed
7377          * to those for other fetches that have joined the same
7378          * fctx) and send it with result = ISC_R_CANCELED.
7379          */
7380         event = NULL;
7381         if (fctx->state != fetchstate_done) {
7382                 for (event = ISC_LIST_HEAD(fctx->events);
7383                      event != NULL;
7384                      event = next_event) {
7385                         next_event = ISC_LIST_NEXT(event, ev_link);
7386                         if (event->fetch == fetch) {
7387                                 ISC_LIST_UNLINK(fctx->events, event, ev_link);
7388                                 break;
7389                         }
7390                 }
7391         }
7392         if (event != NULL) {
7393                 etask = event->ev_sender;
7394                 event->ev_sender = fctx;
7395                 event->result = ISC_R_CANCELED;
7396                 isc_task_sendanddetach(&etask, ISC_EVENT_PTR(&event));
7397         }
7398         /*
7399          * The fctx continues running even if no fetches remain;
7400          * the answer is still cached.
7401          */
7402
7403         UNLOCK(&res->buckets[fctx->bucketnum].lock);
7404 }
7405
7406 void
7407 dns_resolver_destroyfetch(dns_fetch_t **fetchp) {
7408         dns_fetch_t *fetch;
7409         dns_resolver_t *res;
7410         dns_fetchevent_t *event, *next_event;
7411         fetchctx_t *fctx;
7412         unsigned int bucketnum;
7413         isc_boolean_t bucket_empty = ISC_FALSE;
7414
7415         REQUIRE(fetchp != NULL);
7416         fetch = *fetchp;
7417         REQUIRE(DNS_FETCH_VALID(fetch));
7418         fctx = fetch->private;
7419         REQUIRE(VALID_FCTX(fctx));
7420         res = fctx->res;
7421
7422         FTRACE("destroyfetch");
7423
7424         bucketnum = fctx->bucketnum;
7425         LOCK(&res->buckets[bucketnum].lock);
7426
7427         /*
7428          * Sanity check: the caller should have gotten its event before
7429          * trying to destroy the fetch.
7430          */
7431         event = NULL;
7432         if (fctx->state != fetchstate_done) {
7433                 for (event = ISC_LIST_HEAD(fctx->events);
7434                      event != NULL;
7435                      event = next_event) {
7436                         next_event = ISC_LIST_NEXT(event, ev_link);
7437                         RUNTIME_CHECK(event->fetch != fetch);
7438                 }
7439         }
7440
7441         INSIST(fctx->references > 0);
7442         fctx->references--;
7443         if (fctx->references == 0) {
7444                 /*
7445                  * No one cares about the result of this fetch anymore.
7446                  */
7447                 if (fctx->pending == 0 && fctx->nqueries == 0 &&
7448                     ISC_LIST_EMPTY(fctx->validators) &&
7449                     SHUTTINGDOWN(fctx)) {
7450                         /*
7451                          * This fctx is already shutdown; we were just
7452                          * waiting for the last reference to go away.
7453                          */
7454                         bucket_empty = fctx_destroy(fctx);
7455                 } else {
7456                         /*
7457                          * Initiate shutdown.
7458                          */
7459                         fctx_shutdown(fctx);
7460                 }
7461         }
7462
7463         UNLOCK(&res->buckets[bucketnum].lock);
7464
7465         isc_mem_put(res->mctx, fetch, sizeof(*fetch));
7466         *fetchp = NULL;
7467
7468         if (bucket_empty)
7469                 empty_bucket(res);
7470 }
7471
7472 void
7473 dns_resolver_logfetch(dns_fetch_t *fetch, isc_log_t *lctx,
7474                       isc_logcategory_t *category, isc_logmodule_t *module,
7475                       int level, isc_boolean_t duplicateok)
7476 {
7477         fetchctx_t *fctx;
7478         dns_resolver_t *res;
7479         char domainbuf[DNS_NAME_FORMATSIZE];
7480
7481         REQUIRE(DNS_FETCH_VALID(fetch));
7482         fctx = fetch->private;
7483         REQUIRE(VALID_FCTX(fctx));
7484         res = fctx->res;
7485
7486         LOCK(&res->buckets[fctx->bucketnum].lock);
7487
7488         INSIST(fctx->exitline >= 0);
7489         if (!fctx->logged || duplicateok) {
7490                 dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
7491                 isc_log_write(lctx, category, module, level,
7492                               "fetch completed at %s:%d for %s in "
7493                               "%" ISC_PRINT_QUADFORMAT "u."
7494                               "%06" ISC_PRINT_QUADFORMAT "u: %s/%s "
7495                               "[domain:%s,referral:%u,restart:%u,qrysent:%u,"
7496                               "timeout:%u,lame:%u,neterr:%u,badresp:%u,"
7497                               "adberr:%u,findfail:%u,valfail:%u]",
7498                               __FILE__, fctx->exitline, fctx->info,
7499                               fctx->duration / 1000000,
7500                               fctx->duration % 1000000,
7501                               isc_result_totext(fctx->result),
7502                               isc_result_totext(fctx->vresult), domainbuf,
7503                               fctx->referrals, fctx->restarts,
7504                               fctx->querysent, fctx->timeouts, fctx->lamecount,
7505                               fctx->neterr, fctx->badresp, fctx->adberr,
7506                               fctx->findfail, fctx->valfail);
7507                 fctx->logged = ISC_TRUE;
7508         }
7509
7510         UNLOCK(&res->buckets[fctx->bucketnum].lock);
7511 }
7512
7513 dns_dispatchmgr_t *
7514 dns_resolver_dispatchmgr(dns_resolver_t *resolver) {
7515         REQUIRE(VALID_RESOLVER(resolver));
7516         return (resolver->dispatchmgr);
7517 }
7518
7519 dns_dispatch_t *
7520 dns_resolver_dispatchv4(dns_resolver_t *resolver) {
7521         REQUIRE(VALID_RESOLVER(resolver));
7522         return (resolver->dispatchv4);
7523 }
7524
7525 dns_dispatch_t *
7526 dns_resolver_dispatchv6(dns_resolver_t *resolver) {
7527         REQUIRE(VALID_RESOLVER(resolver));
7528         return (resolver->dispatchv6);
7529 }
7530
7531 isc_socketmgr_t *
7532 dns_resolver_socketmgr(dns_resolver_t *resolver) {
7533         REQUIRE(VALID_RESOLVER(resolver));
7534         return (resolver->socketmgr);
7535 }
7536
7537 isc_taskmgr_t *
7538 dns_resolver_taskmgr(dns_resolver_t *resolver) {
7539         REQUIRE(VALID_RESOLVER(resolver));
7540         return (resolver->taskmgr);
7541 }
7542
7543 isc_uint32_t
7544 dns_resolver_getlamettl(dns_resolver_t *resolver) {
7545         REQUIRE(VALID_RESOLVER(resolver));
7546         return (resolver->lame_ttl);
7547 }
7548
7549 void
7550 dns_resolver_setlamettl(dns_resolver_t *resolver, isc_uint32_t lame_ttl) {
7551         REQUIRE(VALID_RESOLVER(resolver));
7552         resolver->lame_ttl = lame_ttl;
7553 }
7554
7555 unsigned int
7556 dns_resolver_nrunning(dns_resolver_t *resolver) {
7557         unsigned int n;
7558         LOCK(&resolver->nlock);
7559         n = resolver->nfctx;
7560         UNLOCK(&resolver->nlock);
7561         return (n);
7562 }
7563
7564 isc_result_t
7565 dns_resolver_addalternate(dns_resolver_t *resolver, isc_sockaddr_t *alt,
7566                           dns_name_t *name, in_port_t port) {
7567         alternate_t *a;
7568         isc_result_t result;
7569
7570         REQUIRE(VALID_RESOLVER(resolver));
7571         REQUIRE(!resolver->frozen);
7572         REQUIRE((alt == NULL) ^ (name == NULL));
7573
7574         a = isc_mem_get(resolver->mctx, sizeof(*a));
7575         if (a == NULL)
7576                 return (ISC_R_NOMEMORY);
7577         if (alt != NULL) {
7578                 a->isaddress = ISC_TRUE;
7579                 a->_u.addr = *alt;
7580         } else {
7581                 a->isaddress = ISC_FALSE;
7582                 a->_u._n.port = port;
7583                 dns_name_init(&a->_u._n.name, NULL);
7584                 result = dns_name_dup(name, resolver->mctx, &a->_u._n.name);
7585                 if (result != ISC_R_SUCCESS) {
7586                         isc_mem_put(resolver->mctx, a, sizeof(*a));
7587                         return (result);
7588                 }
7589         }
7590         ISC_LINK_INIT(a, link);
7591         ISC_LIST_APPEND(resolver->alternates, a, link);
7592
7593         return (ISC_R_SUCCESS);
7594 }
7595
7596 void
7597 dns_resolver_setudpsize(dns_resolver_t *resolver, isc_uint16_t udpsize) {
7598         REQUIRE(VALID_RESOLVER(resolver));
7599         resolver->udpsize = udpsize;
7600 }
7601
7602 isc_uint16_t
7603 dns_resolver_getudpsize(dns_resolver_t *resolver) {
7604         REQUIRE(VALID_RESOLVER(resolver));
7605         return (resolver->udpsize);
7606 }
7607
7608 static void
7609 free_algorithm(void *node, void *arg) {
7610         unsigned char *algorithms = node;
7611         isc_mem_t *mctx = arg;
7612
7613         isc_mem_put(mctx, algorithms, *algorithms);
7614 }
7615
7616 void
7617 dns_resolver_reset_algorithms(dns_resolver_t *resolver) {
7618
7619         REQUIRE(VALID_RESOLVER(resolver));
7620
7621 #if USE_ALGLOCK
7622         RWLOCK(&resolver->alglock, isc_rwlocktype_write);
7623 #endif
7624         if (resolver->algorithms != NULL)
7625                 dns_rbt_destroy(&resolver->algorithms);
7626 #if USE_ALGLOCK
7627         RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
7628 #endif
7629 }
7630
7631 isc_result_t
7632 dns_resolver_disable_algorithm(dns_resolver_t *resolver, dns_name_t *name,
7633                                unsigned int alg)
7634 {
7635         unsigned int len, mask;
7636         unsigned char *new;
7637         unsigned char *algorithms;
7638         isc_result_t result;
7639         dns_rbtnode_t *node = NULL;
7640
7641         REQUIRE(VALID_RESOLVER(resolver));
7642         if (alg > 255)
7643                 return (ISC_R_RANGE);
7644
7645 #if USE_ALGLOCK
7646         RWLOCK(&resolver->alglock, isc_rwlocktype_write);
7647 #endif
7648         if (resolver->algorithms == NULL) {
7649                 result = dns_rbt_create(resolver->mctx, free_algorithm,
7650                                         resolver->mctx, &resolver->algorithms);
7651                 if (result != ISC_R_SUCCESS)
7652                         goto cleanup;
7653         }
7654
7655         len = alg/8 + 2;
7656         mask = 1 << (alg%8);
7657
7658         result = dns_rbt_addnode(resolver->algorithms, name, &node);
7659
7660         if (result == ISC_R_SUCCESS || result == ISC_R_EXISTS) {
7661                 algorithms = node->data;
7662                 if (algorithms == NULL || len > *algorithms) {
7663                         new = isc_mem_get(resolver->mctx, len);
7664                         if (new == NULL) {
7665                                 result = ISC_R_NOMEMORY;
7666                                 goto cleanup;
7667                         }
7668                         memset(new, 0, len);
7669                         if (algorithms != NULL)
7670                                 memcpy(new, algorithms, *algorithms);
7671                         new[len-1] |= mask;
7672                         *new = len;
7673                         node->data = new;
7674                         if (algorithms != NULL)
7675                                 isc_mem_put(resolver->mctx, algorithms,
7676                                             *algorithms);
7677                 } else
7678                         algorithms[len-1] |= mask;
7679         }
7680         result = ISC_R_SUCCESS;
7681  cleanup:
7682 #if USE_ALGLOCK
7683         RWUNLOCK(&resolver->alglock, isc_rwlocktype_write);
7684 #endif
7685         return (result);
7686 }
7687
7688 isc_boolean_t
7689 dns_resolver_algorithm_supported(dns_resolver_t *resolver, dns_name_t *name,
7690                                  unsigned int alg)
7691 {
7692         unsigned int len, mask;
7693         unsigned char *algorithms;
7694         void *data = NULL;
7695         isc_result_t result;
7696         isc_boolean_t found = ISC_FALSE;
7697
7698         REQUIRE(VALID_RESOLVER(resolver));
7699
7700 #if USE_ALGLOCK
7701         RWLOCK(&resolver->alglock, isc_rwlocktype_read);
7702 #endif
7703         if (resolver->algorithms == NULL)
7704                 goto unlock;
7705         result = dns_rbt_findname(resolver->algorithms, name, 0, NULL, &data);
7706         if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
7707                 len = alg/8 + 2;
7708                 mask = 1 << (alg%8);
7709                 algorithms = data;
7710                 if (len <= *algorithms && (algorithms[len-1] & mask) != 0)
7711                         found = ISC_TRUE;
7712         }
7713  unlock:
7714 #if USE_ALGLOCK
7715         RWUNLOCK(&resolver->alglock, isc_rwlocktype_read);
7716 #endif
7717         if (found)
7718                 return (ISC_FALSE);
7719         return (dst_algorithm_supported(alg));
7720 }
7721
7722 isc_boolean_t
7723 dns_resolver_digest_supported(dns_resolver_t *resolver, unsigned int digest) {
7724
7725         UNUSED(resolver);
7726         return (dns_ds_digest_supported(digest));
7727 }
7728
7729 void
7730 dns_resolver_resetmustbesecure(dns_resolver_t *resolver) {
7731
7732         REQUIRE(VALID_RESOLVER(resolver));
7733
7734 #if USE_MBSLOCK
7735         RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
7736 #endif
7737         if (resolver->mustbesecure != NULL)
7738                 dns_rbt_destroy(&resolver->mustbesecure);
7739 #if USE_MBSLOCK
7740         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
7741 #endif
7742 }
7743
7744 static isc_boolean_t yes = ISC_TRUE, no = ISC_FALSE;
7745
7746 isc_result_t
7747 dns_resolver_setmustbesecure(dns_resolver_t *resolver, dns_name_t *name,
7748                              isc_boolean_t value)
7749 {
7750         isc_result_t result;
7751
7752         REQUIRE(VALID_RESOLVER(resolver));
7753
7754 #if USE_MBSLOCK
7755         RWLOCK(&resolver->mbslock, isc_rwlocktype_write);
7756 #endif
7757         if (resolver->mustbesecure == NULL) {
7758                 result = dns_rbt_create(resolver->mctx, NULL, NULL,
7759                                         &resolver->mustbesecure);
7760                 if (result != ISC_R_SUCCESS)
7761                         goto cleanup;
7762         }
7763         result = dns_rbt_addname(resolver->mustbesecure, name,
7764                                  value ? &yes : &no);
7765  cleanup:
7766 #if USE_MBSLOCK
7767         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_write);
7768 #endif
7769         return (result);
7770 }
7771
7772 isc_boolean_t
7773 dns_resolver_getmustbesecure(dns_resolver_t *resolver, dns_name_t *name) {
7774         void *data = NULL;
7775         isc_boolean_t value = ISC_FALSE;
7776         isc_result_t result;
7777
7778         REQUIRE(VALID_RESOLVER(resolver));
7779
7780 #if USE_MBSLOCK
7781         RWLOCK(&resolver->mbslock, isc_rwlocktype_read);
7782 #endif
7783         if (resolver->mustbesecure == NULL)
7784                 goto unlock;
7785         result = dns_rbt_findname(resolver->mustbesecure, name, 0, NULL, &data);
7786         if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
7787                 value = *(isc_boolean_t*)data;
7788  unlock:
7789 #if USE_MBSLOCK
7790         RWUNLOCK(&resolver->mbslock, isc_rwlocktype_read);
7791 #endif
7792         return (value);
7793 }
7794
7795 void
7796 dns_resolver_getclientsperquery(dns_resolver_t *resolver, isc_uint32_t *cur,
7797                                 isc_uint32_t *min, isc_uint32_t *max)
7798 {
7799         REQUIRE(VALID_RESOLVER(resolver));
7800
7801         LOCK(&resolver->lock);
7802         if (cur != NULL)
7803                 *cur = resolver->spillat;
7804         if (min != NULL)
7805                 *min = resolver->spillatmin;
7806         if (max != NULL)
7807                 *max = resolver->spillatmax;
7808         UNLOCK(&resolver->lock);
7809 }
7810
7811 void
7812 dns_resolver_setclientsperquery(dns_resolver_t *resolver, isc_uint32_t min,
7813                                 isc_uint32_t max)
7814 {
7815         REQUIRE(VALID_RESOLVER(resolver));
7816
7817         LOCK(&resolver->lock);
7818         resolver->spillatmin = resolver->spillat = min;
7819         resolver->spillatmax = max;
7820         UNLOCK(&resolver->lock);
7821 }
7822
7823 isc_boolean_t
7824 dns_resolver_getzeronosoattl(dns_resolver_t *resolver) {
7825         REQUIRE(VALID_RESOLVER(resolver));
7826
7827         return (resolver->zero_no_soa_ttl);
7828 }
7829
7830 void
7831 dns_resolver_setzeronosoattl(dns_resolver_t *resolver, isc_boolean_t state) {
7832         REQUIRE(VALID_RESOLVER(resolver));
7833
7834         resolver->zero_no_soa_ttl = state;
7835 }
7836
7837 unsigned int
7838 dns_resolver_getoptions(dns_resolver_t *resolver) {
7839         REQUIRE(VALID_RESOLVER(resolver));
7840
7841         return (resolver->options);
7842 }