contrib/bind-9.5.2/bin/named/lwresd.c

   1 /*
   2  * Copyright (C) 2004-2008  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000-2003  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: lwresd.c,v 1.55.130.3 2008/07/23 23:31:17 marka Exp $ */
  19
  20 /*! \file
  21  * \brief
  22  * Main program for the Lightweight Resolver Daemon.
  23  *
  24  * To paraphrase the old saying about X11, "It's not a lightweight deamon
  25  * for resolvers, it's a deamon for lightweight resolvers".
  26  */
  27
  28 #include <config.h>
  29
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include <isc/list.h>
  34 #include <isc/magic.h>
  35 #include <isc/mem.h>
  36 #include <isc/once.h>
  37 #include <isc/print.h>
  38 #include <isc/socket.h>
  39 #include <isc/task.h>
  40 #include <isc/util.h>
  41
  42 #include <isccfg/namedconf.h>
  43
  44 #include <dns/log.h>
  45 #include <dns/result.h>
  46 #include <dns/view.h>
  47
  48 #include <named/config.h>
  49 #include <named/globals.h>
  50 #include <named/log.h>
  51 #include <named/lwaddr.h>
  52 #include <named/lwresd.h>
  53 #include <named/lwdclient.h>
  54 #include <named/lwsearch.h>
  55 #include <named/server.h>
  56
  57 #define LWRESD_MAGIC            ISC_MAGIC('L', 'W', 'R', 'D')
  58 #define VALID_LWRESD(l)         ISC_MAGIC_VALID(l, LWRESD_MAGIC)
  59
  60 #define LWRESLISTENER_MAGIC     ISC_MAGIC('L', 'W', 'R', 'L')
  61 #define VALID_LWRESLISTENER(l)  ISC_MAGIC_VALID(l, LWRESLISTENER_MAGIC)
  62
  63 /*!
  64  * The total number of clients we can handle will be NTASKS * NRECVS.
  65  */
  66 #define NTASKS          2       /*%< tasks to create to handle lwres queries */
  67 #define NRECVS          2       /*%< max clients per task */
  68
  69 typedef ISC_LIST(ns_lwreslistener_t) ns_lwreslistenerlist_t;
  70
  71 static ns_lwreslistenerlist_t listeners;
  72 static isc_mutex_t listeners_lock;
  73 static isc_once_t once = ISC_ONCE_INIT;
  74
  75
  76 static void
  77 initialize_mutex(void) {
  78         RUNTIME_CHECK(isc_mutex_init(&listeners_lock) == ISC_R_SUCCESS);
  79 }
  80
  81
  82 /*%
  83  * Wrappers around our memory management stuff, for the lwres functions.
  84  */
  85 void *
  86 ns__lwresd_memalloc(void *arg, size_t size) {
  87         return (isc_mem_get(arg, size));
  88 }
  89
  90 void
  91 ns__lwresd_memfree(void *arg, void *mem, size_t size) {
  92         isc_mem_put(arg, mem, size);
  93 }
  94
  95
  96 #define CHECK(op)                                               \
  97         do { result = (op);                                     \
  98                 if (result != ISC_R_SUCCESS) goto cleanup;      \
  99         } while (0)
 100
 101 static isc_result_t
 102 buffer_putstr(isc_buffer_t *b, const char *s) {
 103         unsigned int len = strlen(s);
 104         if (isc_buffer_availablelength(b) <= len)
 105                 return (ISC_R_NOSPACE);
 106         isc_buffer_putmem(b, (const unsigned char *)s, len);
 107         return (ISC_R_SUCCESS);
 108 }
 109
 110 /*
 111  * Convert a resolv.conf file into a config structure.
 112  */
 113 isc_result_t
 114 ns_lwresd_parseeresolvconf(isc_mem_t *mctx, cfg_parser_t *pctx,
 115                            cfg_obj_t **configp)
 116 {
 117         char text[4096];
 118         char str[16];
 119         isc_buffer_t b;
 120         lwres_context_t *lwctx = NULL;
 121         lwres_conf_t *lwc = NULL;
 122         isc_sockaddr_t sa;
 123         isc_netaddr_t na;
 124         int i;
 125         isc_result_t result;
 126         lwres_result_t lwresult;
 127
 128         lwctx = NULL;
 129         lwresult = lwres_context_create(&lwctx, mctx, ns__lwresd_memalloc,
 130                                         ns__lwresd_memfree,
 131                                         LWRES_CONTEXT_SERVERMODE);
 132         if (lwresult != LWRES_R_SUCCESS) {
 133                 result = ISC_R_NOMEMORY;
 134                 goto cleanup;
 135         }
 136
 137         lwresult = lwres_conf_parse(lwctx, lwresd_g_resolvconffile);
 138         if (lwresult != LWRES_R_SUCCESS) {
 139                 result = DNS_R_SYNTAX;
 140                 goto cleanup;
 141         }
 142
 143         lwc = lwres_conf_get(lwctx);
 144         INSIST(lwc != NULL);
 145
 146         isc_buffer_init(&b, text, sizeof(text));
 147
 148         CHECK(buffer_putstr(&b, "options {\n"));
 149
 150         /*
 151          * Build the list of forwarders.
 152          */
 153         if (lwc->nsnext > 0) {
 154                 CHECK(buffer_putstr(&b, "\tforwarders {\n"));
 155
 156                 for (i = 0; i < lwc->nsnext; i++) {
 157                         CHECK(lwaddr_sockaddr_fromlwresaddr(
 158                                                         &sa,
 159                                                         &lwc->nameservers[i],
 160                                                         ns_g_port));
 161                         isc_netaddr_fromsockaddr(&na, &sa);
 162                         CHECK(buffer_putstr(&b, "\t\t"));
 163                         CHECK(isc_netaddr_totext(&na, &b));
 164                         CHECK(buffer_putstr(&b, ";\n"));
 165                 }
 166                 CHECK(buffer_putstr(&b, "\t};\n"));
 167         }
 168
 169         /*
 170          * Build the sortlist
 171          */
 172         if (lwc->sortlistnxt > 0) {
 173                 CHECK(buffer_putstr(&b, "\tsortlist {\n"));
 174                 CHECK(buffer_putstr(&b, "\t\t{\n"));
 175                 CHECK(buffer_putstr(&b, "\t\t\tany;\n"));
 176                 CHECK(buffer_putstr(&b, "\t\t\t{\n"));
 177                 for (i = 0; i < lwc->sortlistnxt; i++) {
 178                         lwres_addr_t *lwaddr = &lwc->sortlist[i].addr;
 179                         lwres_addr_t *lwmask = &lwc->sortlist[i].mask;
 180                         unsigned int mask;
 181
 182                         CHECK(lwaddr_sockaddr_fromlwresaddr(&sa, lwmask, 0));
 183                         isc_netaddr_fromsockaddr(&na, &sa);
 184                         result = isc_netaddr_masktoprefixlen(&na, &mask);
 185                         if (result != ISC_R_SUCCESS) {
 186                                 char addrtext[ISC_NETADDR_FORMATSIZE];
 187                                 isc_netaddr_format(&na, addrtext,
 188                                                    sizeof(addrtext));
 189                                 isc_log_write(ns_g_lctx,
 190                                               NS_LOGCATEGORY_GENERAL,
 191                                               NS_LOGMODULE_LWRESD,
 192                                               ISC_LOG_ERROR,
 193                                               "processing sortlist: '%s' is "
 194                                               "not a valid netmask",
 195                                               addrtext);
 196                                 goto cleanup;
 197                         }
 198
 199                         CHECK(lwaddr_sockaddr_fromlwresaddr(&sa, lwaddr, 0));
 200                         isc_netaddr_fromsockaddr(&na, &sa);
 201
 202                         CHECK(buffer_putstr(&b, "\t\t\t\t"));
 203                         CHECK(isc_netaddr_totext(&na, &b));
 204                         snprintf(str, sizeof(str), "%u", mask);
 205                         CHECK(buffer_putstr(&b, "/"));
 206                         CHECK(buffer_putstr(&b, str));
 207                         CHECK(buffer_putstr(&b, ";\n"));
 208                 }
 209                 CHECK(buffer_putstr(&b, "\t\t\t};\n"));
 210                 CHECK(buffer_putstr(&b, "\t\t};\n"));
 211                 CHECK(buffer_putstr(&b, "\t};\n"));
 212         }
 213
 214         CHECK(buffer_putstr(&b, "};\n\n"));
 215
 216         CHECK(buffer_putstr(&b, "lwres {\n"));
 217
 218         /*
 219          * Build the search path
 220          */
 221         if (lwc->searchnxt > 0) {
 222                 if (lwc->searchnxt > 0) {
 223                         CHECK(buffer_putstr(&b, "\tsearch {\n"));
 224                         for (i = 0; i < lwc->searchnxt; i++) {
 225                                 CHECK(buffer_putstr(&b, "\t\t\""));
 226                                 CHECK(buffer_putstr(&b, lwc->search[i]));
 227                                 CHECK(buffer_putstr(&b, "\";\n"));
 228                         }
 229                         CHECK(buffer_putstr(&b, "\t};\n"));
 230                 }
 231         }
 232
 233         /*
 234          * Build the ndots line
 235          */
 236         if (lwc->ndots != 1) {
 237                 CHECK(buffer_putstr(&b, "\tndots "));
 238                 snprintf(str, sizeof(str), "%u", lwc->ndots);
 239                 CHECK(buffer_putstr(&b, str));
 240                 CHECK(buffer_putstr(&b, ";\n"));
 241         }
 242
 243         /*
 244          * Build the listen-on line
 245          */
 246         if (lwc->lwnext > 0) {
 247                 CHECK(buffer_putstr(&b, "\tlisten-on {\n"));
 248
 249                 for (i = 0; i < lwc->lwnext; i++) {
 250                         CHECK(lwaddr_sockaddr_fromlwresaddr(&sa,
 251                                                             &lwc->lwservers[i],
 252                                                             0));
 253                         isc_netaddr_fromsockaddr(&na, &sa);
 254                         CHECK(buffer_putstr(&b, "\t\t"));
 255                         CHECK(isc_netaddr_totext(&na, &b));
 256                         CHECK(buffer_putstr(&b, ";\n"));
 257                 }
 258                 CHECK(buffer_putstr(&b, "\t};\n"));
 259         }
 260
 261         CHECK(buffer_putstr(&b, "};\n"));
 262
 263 #if 0
 264         printf("%.*s\n",
 265                (int)isc_buffer_usedlength(&b),
 266                (char *)isc_buffer_base(&b));
 267 #endif
 268
 269         lwres_conf_clear(lwctx);
 270         lwres_context_destroy(&lwctx);
 271
 272         return (cfg_parse_buffer(pctx, &b, &cfg_type_namedconf, configp));
 273
 274  cleanup:
 275
 276         if (lwctx != NULL) {
 277                 lwres_conf_clear(lwctx);
 278                 lwres_context_destroy(&lwctx);
 279         }
 280
 281         return (result);
 282 }
 283
 284
 285 /*
 286  * Handle lwresd manager objects
 287  */
 288 isc_result_t
 289 ns_lwdmanager_create(isc_mem_t *mctx, const cfg_obj_t *lwres,
 290                      ns_lwresd_t **lwresdp)
 291 {
 292         ns_lwresd_t *lwresd;
 293         const char *vname;
 294         dns_rdataclass_t vclass;
 295         const cfg_obj_t *obj, *viewobj, *searchobj;
 296         const cfg_listelt_t *element;
 297         isc_result_t result;
 298
 299         INSIST(lwresdp != NULL && *lwresdp == NULL);
 300
 301         lwresd = isc_mem_get(mctx, sizeof(ns_lwresd_t));
 302         if (lwresd == NULL)
 303                 return (ISC_R_NOMEMORY);
 304
 305         lwresd->mctx = NULL;
 306         isc_mem_attach(mctx, &lwresd->mctx);
 307         lwresd->view = NULL;
 308         lwresd->search = NULL;
 309         lwresd->refs = 1;
 310
 311         obj = NULL;
 312         (void)cfg_map_get(lwres, "ndots", &obj);
 313         if (obj != NULL)
 314                 lwresd->ndots = cfg_obj_asuint32(obj);
 315         else
 316                 lwresd->ndots = 1;
 317
 318         RUNTIME_CHECK(isc_mutex_init(&lwresd->lock) == ISC_R_SUCCESS);
 319
 320         lwresd->shutting_down = ISC_FALSE;
 321
 322         viewobj = NULL;
 323         (void)cfg_map_get(lwres, "view", &viewobj);
 324         if (viewobj != NULL) {
 325                 vname = cfg_obj_asstring(cfg_tuple_get(viewobj, "name"));
 326                 obj = cfg_tuple_get(viewobj, "class");
 327                 result = ns_config_getclass(obj, dns_rdataclass_in, &vclass);
 328                 if (result != ISC_R_SUCCESS)
 329                         goto fail;
 330         } else {
 331                 vname = "_default";
 332                 vclass = dns_rdataclass_in;
 333         }
 334
 335         result = dns_viewlist_find(&ns_g_server->viewlist, vname, vclass,
 336                                    &lwresd->view);
 337         if (result != ISC_R_SUCCESS) {
 338                 isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 339                               NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 340                               "couldn't find view %s", vname);
 341                 goto fail;
 342         }
 343
 344         searchobj = NULL;
 345         (void)cfg_map_get(lwres, "search", &searchobj);
 346         if (searchobj != NULL) {
 347                 lwresd->search = NULL;
 348                 result = ns_lwsearchlist_create(lwresd->mctx,
 349                                                 &lwresd->search);
 350                 if (result != ISC_R_SUCCESS) {
 351                         isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 352                                       NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 353                                       "couldn't create searchlist");
 354                         goto fail;
 355                 }
 356                 for (element = cfg_list_first(searchobj);
 357                      element != NULL;
 358                      element = cfg_list_next(element))
 359                 {
 360                         const cfg_obj_t *search;
 361                         const char *searchstr;
 362                         isc_buffer_t namebuf;
 363                         dns_fixedname_t fname;
 364                         dns_name_t *name;
 365
 366                         search = cfg_listelt_value(element);
 367                         searchstr = cfg_obj_asstring(search);
 368
 369                         dns_fixedname_init(&fname);
 370                         name = dns_fixedname_name(&fname);
 371                         isc_buffer_init(&namebuf, searchstr,
 372                                         strlen(searchstr));
 373                         isc_buffer_add(&namebuf, strlen(searchstr));
 374                         result = dns_name_fromtext(name, &namebuf,
 375                                                    dns_rootname, ISC_FALSE,
 376                                                    NULL);
 377                         if (result != ISC_R_SUCCESS) {
 378                                 isc_log_write(ns_g_lctx,
 379                                               NS_LOGCATEGORY_GENERAL,
 380                                               NS_LOGMODULE_LWRESD,
 381                                               ISC_LOG_WARNING,
 382                                               "invalid name %s in searchlist",
 383                                               searchstr);
 384                                 continue;
 385                         }
 386
 387                         result = ns_lwsearchlist_append(lwresd->search, name);
 388                         if (result != ISC_R_SUCCESS) {
 389                                 isc_log_write(ns_g_lctx,
 390                                               NS_LOGCATEGORY_GENERAL,
 391                                               NS_LOGMODULE_LWRESD,
 392                                               ISC_LOG_WARNING,
 393                                               "couldn't update searchlist");
 394                                 goto fail;
 395                         }
 396                 }
 397         }
 398
 399         lwresd->magic = LWRESD_MAGIC;
 400
 401         *lwresdp = lwresd;
 402         return (ISC_R_SUCCESS);
 403
 404  fail:
 405         if (lwresd->view != NULL)
 406                 dns_view_detach(&lwresd->view);
 407         if (lwresd->search != NULL)
 408                 ns_lwsearchlist_detach(&lwresd->search);
 409         if (lwresd->mctx != NULL)
 410                 isc_mem_detach(&lwresd->mctx);
 411         isc_mem_put(mctx, lwresd, sizeof(ns_lwresd_t));
 412         return (result);
 413 }
 414
 415 void
 416 ns_lwdmanager_attach(ns_lwresd_t *source, ns_lwresd_t **targetp) {
 417         INSIST(VALID_LWRESD(source));
 418         INSIST(targetp != NULL && *targetp == NULL);
 419
 420         LOCK(&source->lock);
 421         source->refs++;
 422         UNLOCK(&source->lock);
 423
 424         *targetp = source;
 425 }
 426
 427 void
 428 ns_lwdmanager_detach(ns_lwresd_t **lwresdp) {
 429         ns_lwresd_t *lwresd;
 430         isc_mem_t *mctx;
 431         isc_boolean_t done = ISC_FALSE;
 432
 433         INSIST(lwresdp != NULL && *lwresdp != NULL);
 434         INSIST(VALID_LWRESD(*lwresdp));
 435
 436         lwresd = *lwresdp;
 437         *lwresdp = NULL;
 438
 439         LOCK(&lwresd->lock);
 440         INSIST(lwresd->refs > 0);
 441         lwresd->refs--;
 442         if (lwresd->refs == 0)
 443                 done = ISC_TRUE;
 444         UNLOCK(&lwresd->lock);
 445
 446         if (!done)
 447                 return;
 448
 449         dns_view_detach(&lwresd->view);
 450         if (lwresd->search != NULL)
 451                 ns_lwsearchlist_detach(&lwresd->search);
 452         mctx = lwresd->mctx;
 453         lwresd->magic = 0;
 454         isc_mem_put(mctx, lwresd, sizeof(*lwresd));
 455         isc_mem_detach(&mctx);
 456 }
 457
 458
 459 /*
 460  * Handle listener objects
 461  */
 462 void
 463 ns_lwreslistener_attach(ns_lwreslistener_t *source,
 464                         ns_lwreslistener_t **targetp)
 465 {
 466         INSIST(VALID_LWRESLISTENER(source));
 467         INSIST(targetp != NULL && *targetp == NULL);
 468
 469         LOCK(&source->lock);
 470         source->refs++;
 471         UNLOCK(&source->lock);
 472
 473         *targetp = source;
 474 }
 475
 476 void
 477 ns_lwreslistener_detach(ns_lwreslistener_t **listenerp) {
 478         ns_lwreslistener_t *listener;
 479         isc_mem_t *mctx;
 480         isc_boolean_t done = ISC_FALSE;
 481
 482         INSIST(listenerp != NULL && *listenerp != NULL);
 483         INSIST(VALID_LWRESLISTENER(*listenerp));
 484
 485         listener = *listenerp;
 486
 487         LOCK(&listener->lock);
 488         INSIST(listener->refs > 0);
 489         listener->refs--;
 490         if (listener->refs == 0)
 491                 done = ISC_TRUE;
 492         UNLOCK(&listener->lock);
 493
 494         if (!done)
 495                 return;
 496
 497         if (listener->manager != NULL)
 498                 ns_lwdmanager_detach(&listener->manager);
 499
 500         if (listener->sock != NULL)
 501                 isc_socket_detach(&listener->sock);
 502
 503         listener->magic = 0;
 504         mctx = listener->mctx;
 505         isc_mem_put(mctx, listener, sizeof(*listener));
 506         isc_mem_detach(&mctx);
 507         listenerp = NULL;
 508 }
 509
 510 static isc_result_t
 511 listener_create(isc_mem_t *mctx, ns_lwresd_t *lwresd,
 512                 ns_lwreslistener_t **listenerp)
 513 {
 514         ns_lwreslistener_t *listener;
 515         isc_result_t result;
 516
 517         REQUIRE(listenerp != NULL && *listenerp == NULL);
 518
 519         listener = isc_mem_get(mctx, sizeof(ns_lwreslistener_t));
 520         if (listener == NULL)
 521                 return (ISC_R_NOMEMORY);
 522
 523         result = isc_mutex_init(&listener->lock);
 524         if (result != ISC_R_SUCCESS) {
 525                 isc_mem_put(mctx, listener, sizeof(ns_lwreslistener_t));
 526                 return (result);
 527         }
 528
 529         listener->magic = LWRESLISTENER_MAGIC;
 530         listener->refs = 1;
 531
 532         listener->sock = NULL;
 533
 534         listener->manager = NULL;
 535         ns_lwdmanager_attach(lwresd, &listener->manager);
 536
 537         listener->mctx = NULL;
 538         isc_mem_attach(mctx, &listener->mctx);
 539
 540         ISC_LINK_INIT(listener, link);
 541         ISC_LIST_INIT(listener->cmgrs);
 542
 543         *listenerp = listener;
 544         return (ISC_R_SUCCESS);
 545 }
 546
 547 static isc_result_t
 548 listener_bind(ns_lwreslistener_t *listener, isc_sockaddr_t *address) {
 549         isc_socket_t *sock = NULL;
 550         isc_result_t result = ISC_R_SUCCESS;
 551         int pf;
 552
 553         pf = isc_sockaddr_pf(address);
 554         if ((pf == AF_INET && isc_net_probeipv4() != ISC_R_SUCCESS) ||
 555             (pf == AF_INET6 && isc_net_probeipv6() != ISC_R_SUCCESS))
 556                 return (ISC_R_FAMILYNOSUPPORT);
 557
 558         listener->address = *address;
 559
 560         if (isc_sockaddr_getport(&listener->address) == 0) {
 561                 in_port_t port;
 562                 port = lwresd_g_listenport;
 563                 if (port == 0)
 564                         port = LWRES_UDP_PORT;
 565                 isc_sockaddr_setport(&listener->address, port);
 566         }
 567
 568         sock = NULL;
 569         result = isc_socket_create(ns_g_socketmgr, pf,
 570                                    isc_sockettype_udp, &sock);
 571         if (result != ISC_R_SUCCESS) {
 572                 isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 573                               NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 574                               "failed to create lwres socket: %s",
 575                               isc_result_totext(result));
 576                 return (result);
 577         }
 578
 579         result = isc_socket_bind(sock, &listener->address,
 580                                  ISC_SOCKET_REUSEADDRESS);
 581         if (result != ISC_R_SUCCESS) {
 582                 char socktext[ISC_SOCKADDR_FORMATSIZE];
 583                 isc_sockaddr_format(&listener->address, socktext,
 584                                     sizeof(socktext));
 585                 isc_socket_detach(&sock);
 586                 isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 587                               NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 588                               "failed to add lwres socket: %s: %s",
 589                               socktext, isc_result_totext(result));
 590                 return (result);
 591         }
 592         listener->sock = sock;
 593         return (ISC_R_SUCCESS);
 594 }
 595
 596 static void
 597 listener_copysock(ns_lwreslistener_t *oldlistener,
 598                   ns_lwreslistener_t *newlistener)
 599 {
 600         newlistener->address = oldlistener->address;
 601         isc_socket_attach(oldlistener->sock, &newlistener->sock);
 602 }
 603
 604 static isc_result_t
 605 listener_startclients(ns_lwreslistener_t *listener) {
 606         ns_lwdclientmgr_t *cm;
 607         unsigned int i;
 608         isc_result_t result;
 609
 610         /*
 611          * Create the client managers.
 612          */
 613         result = ISC_R_SUCCESS;
 614         for (i = 0; i < NTASKS && result == ISC_R_SUCCESS; i++)
 615                 result = ns_lwdclientmgr_create(listener, NRECVS,
 616                                                 ns_g_taskmgr);
 617
 618         /*
 619          * Ensure that we have created at least one.
 620          */
 621         if (ISC_LIST_EMPTY(listener->cmgrs))
 622                 return (result);
 623
 624         /*
 625          * Walk the list of clients and start each one up.
 626          */
 627         LOCK(&listener->lock);
 628         cm = ISC_LIST_HEAD(listener->cmgrs);
 629         while (cm != NULL) {
 630                 result = ns_lwdclient_startrecv(cm);
 631                 if (result != ISC_R_SUCCESS)
 632                         isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
 633                                       NS_LOGMODULE_LWRESD, ISC_LOG_ERROR,
 634                                       "could not start lwres "
 635                                       "client handler: %s",
 636                                       isc_result_totext(result));
 637                 cm = ISC_LIST_NEXT(cm, link);
 638         }
 639         UNLOCK(&listener->lock);
 640
 641         return (ISC_R_SUCCESS);
 642 }
 643
 644 static void
 645 listener_shutdown(ns_lwreslistener_t *listener) {
 646         ns_lwdclientmgr_t *cm;
 647
 648         cm = ISC_LIST_HEAD(listener->cmgrs);
 649         while (cm != NULL) {
 650                 isc_task_shutdown(cm->task);
 651                 cm = ISC_LIST_NEXT(cm, link);
 652         }
 653 }
 654
 655 static isc_result_t
 656 find_listener(isc_sockaddr_t *address, ns_lwreslistener_t **listenerp) {
 657         ns_lwreslistener_t *listener;
 658
 659         INSIST(listenerp != NULL && *listenerp == NULL);
 660
 661         for (listener = ISC_LIST_HEAD(listeners);
 662              listener != NULL;
 663              listener = ISC_LIST_NEXT(listener, link))
 664         {
 665                 if (!isc_sockaddr_equal(address, &listener->address))
 666                         continue;
 667                 *listenerp = listener;
 668                 return (ISC_R_SUCCESS);
 669         }
 670         return (ISC_R_NOTFOUND);
 671 }
 672
 673 void
 674 ns_lwreslistener_unlinkcm(ns_lwreslistener_t *listener, ns_lwdclientmgr_t *cm)
 675 {
 676         REQUIRE(VALID_LWRESLISTENER(listener));
 677
 678         LOCK(&listener->lock);
 679         ISC_LIST_UNLINK(listener->cmgrs, cm, link);
 680         UNLOCK(&listener->lock);
 681 }
 682
 683 void
 684 ns_lwreslistener_linkcm(ns_lwreslistener_t *listener, ns_lwdclientmgr_t *cm) {
 685         REQUIRE(VALID_LWRESLISTENER(listener));
 686
 687         /*
 688          * This does no locking, since it's called early enough that locking
 689          * isn't needed.
 690          */
 691         ISC_LIST_APPEND(listener->cmgrs, cm, link);
 692 }
 693
 694 static isc_result_t
 695 configure_listener(isc_sockaddr_t *address, ns_lwresd_t *lwresd,
 696                    isc_mem_t *mctx, ns_lwreslistenerlist_t *newlisteners)
 697 {
 698         ns_lwreslistener_t *listener, *oldlistener = NULL;
 699         char socktext[ISC_SOCKADDR_FORMATSIZE];
 700         isc_result_t result;
 701
 702         (void)find_listener(address, &oldlistener);
 703         listener = NULL;
 704         result = listener_create(mctx, lwresd, &listener);
 705         if (result != ISC_R_SUCCESS) {
 706                 isc_sockaddr_format(address, socktext, sizeof(socktext));
 707                 isc_log_write(ns_g_lctx, ISC_LOGCATEGORY_GENERAL,
 708                               NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 709                               "lwres failed to configure %s: %s",
 710                               socktext, isc_result_totext(result));
 711                 return (result);
 712         }
 713
 714         /*
 715          * If there's already a listener, don't rebind the socket.
 716          */
 717         if (oldlistener == NULL) {
 718                 result = listener_bind(listener, address);
 719                 if (result != ISC_R_SUCCESS) {
 720                         ns_lwreslistener_detach(&listener);
 721                         return (ISC_R_SUCCESS);
 722                 }
 723         } else
 724                 listener_copysock(oldlistener, listener);
 725
 726         result = listener_startclients(listener);
 727         if (result != ISC_R_SUCCESS) {
 728                 isc_sockaddr_format(address, socktext, sizeof(socktext));
 729                 isc_log_write(ns_g_lctx, ISC_LOGCATEGORY_GENERAL,
 730                               NS_LOGMODULE_LWRESD, ISC_LOG_WARNING,
 731                               "lwres: failed to start %s: %s", socktext,
 732                               isc_result_totext(result));
 733                 ns_lwreslistener_detach(&listener);
 734                 return (ISC_R_SUCCESS);
 735         }
 736
 737         if (oldlistener != NULL) {
 738                 /*
 739                  * Remove the old listener from the old list and shut it down.
 740                  */
 741                 ISC_LIST_UNLINK(listeners, oldlistener, link);
 742                 listener_shutdown(oldlistener);
 743                 ns_lwreslistener_detach(&oldlistener);
 744         } else {
 745                 isc_sockaddr_format(address, socktext, sizeof(socktext));
 746                 isc_log_write(ns_g_lctx, ISC_LOGCATEGORY_GENERAL,
 747                               NS_LOGMODULE_LWRESD, ISC_LOG_NOTICE,
 748                               "lwres listening on %s", socktext);
 749         }
 750
 751         ISC_LIST_APPEND(*newlisteners, listener, link);
 752         return (result);
 753 }
 754
 755 isc_result_t
 756 ns_lwresd_configure(isc_mem_t *mctx, const cfg_obj_t *config) {
 757         const cfg_obj_t *lwreslist = NULL;
 758         const cfg_obj_t *lwres = NULL;
 759         const cfg_obj_t *listenerslist = NULL;
 760         const cfg_listelt_t *element = NULL;
 761         ns_lwreslistener_t *listener;
 762         ns_lwreslistenerlist_t newlisteners;
 763         isc_result_t result;
 764         char socktext[ISC_SOCKADDR_FORMATSIZE];
 765         isc_sockaddr_t *addrs = NULL;
 766         ns_lwresd_t *lwresd = NULL;
 767         isc_uint32_t count = 0;
 768
 769         REQUIRE(mctx != NULL);
 770         REQUIRE(config != NULL);
 771
 772         RUNTIME_CHECK(isc_once_do(&once, initialize_mutex) == ISC_R_SUCCESS);
 773
 774         ISC_LIST_INIT(newlisteners);
 775
 776         result = cfg_map_get(config, "lwres", &lwreslist);
 777         if (result != ISC_R_SUCCESS)
 778                 return (ISC_R_SUCCESS);
 779
 780         LOCK(&listeners_lock);
 781         /*
 782          * Run through the new lwres address list, noting sockets that
 783          * are already being listened on and moving them to the new list.
 784          *
 785          * Identifying duplicates addr/port combinations is left to either
 786          * the underlying config code, or to the bind attempt getting an
 787          * address-in-use error.
 788          */
 789         for (element = cfg_list_first(lwreslist);
 790              element != NULL;
 791              element = cfg_list_next(element))
 792         {
 793                 in_port_t port;
 794
 795                 lwres = cfg_listelt_value(element);
 796                 CHECK(ns_lwdmanager_create(mctx, lwres, &lwresd));
 797
 798                 port = lwresd_g_listenport;
 799                 if (port == 0)
 800                         port = LWRES_UDP_PORT;
 801
 802                 listenerslist = NULL;
 803                 (void)cfg_map_get(lwres, "listen-on", &listenerslist);
 804                 if (listenerslist == NULL) {
 805                         struct in_addr localhost;
 806                         isc_sockaddr_t address;
 807
 808                         localhost.s_addr = htonl(INADDR_LOOPBACK);
 809                         isc_sockaddr_fromin(&address, &localhost, port);
 810                         CHECK(configure_listener(&address, lwresd, mctx,
 811                                                  &newlisteners));
 812                 } else {
 813                         isc_uint32_t i;
 814
 815                         CHECK(ns_config_getiplist(config, listenerslist,
 816                                                   port, mctx, &addrs, &count));
 817                         for (i = 0; i < count; i++)
 818                                 CHECK(configure_listener(&addrs[i], lwresd,
 819                                                          mctx, &newlisteners));
 820                         ns_config_putiplist(mctx, &addrs, count);
 821                 }
 822                 ns_lwdmanager_detach(&lwresd);
 823         }
 824
 825         /*
 826          * Shutdown everything on the listeners list, and remove them from
 827          * the list.  Then put all of the new listeners on it.
 828          */
 829
 830         while (!ISC_LIST_EMPTY(listeners)) {
 831                 listener = ISC_LIST_HEAD(listeners);
 832                 ISC_LIST_UNLINK(listeners, listener, link);
 833
 834                 isc_sockaddr_format(&listener->address,
 835                                     socktext, sizeof(socktext));
 836
 837                 listener_shutdown(listener);
 838                 ns_lwreslistener_detach(&listener);
 839
 840                 isc_log_write(ns_g_lctx, ISC_LOGCATEGORY_GENERAL,
 841                               NS_LOGMODULE_LWRESD, ISC_LOG_NOTICE,
 842                               "lwres no longer listening on %s", socktext);
 843         }
 844
 845  cleanup:
 846         ISC_LIST_APPENDLIST(listeners, newlisteners, link);
 847
 848         if (addrs != NULL)
 849                 ns_config_putiplist(mctx, &addrs, count);
 850
 851         if (lwresd != NULL)
 852                 ns_lwdmanager_detach(&lwresd);
 853
 854         UNLOCK(&listeners_lock);
 855
 856         return (result);
 857 }
 858
 859 void
 860 ns_lwresd_shutdown(void) {
 861         ns_lwreslistener_t *listener;
 862
 863         RUNTIME_CHECK(isc_once_do(&once, initialize_mutex) == ISC_R_SUCCESS);
 864
 865         while (!ISC_LIST_EMPTY(listeners)) {
 866                 listener = ISC_LIST_HEAD(listeners);
 867                 ISC_LIST_UNLINK(listeners, listener, link);
 868                 ns_lwreslistener_detach(&listener);
 869         }
 870 }