contrib/bind-9.3/bin/named/client.c

   1 /*
   2  * Copyright (C) 2004-2006  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2003  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and 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: client.c,v 1.176.2.13.4.31.6.1 2007/06/26 04:14:55 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <isc/formatcheck.h>
  23 #include <isc/mutex.h>
  24 #include <isc/once.h>
  25 #include <isc/print.h>
  26 #include <isc/stdio.h>
  27 #include <isc/string.h>
  28 #include <isc/task.h>
  29 #include <isc/timer.h>
  30 #include <isc/util.h>
  31
  32 #include <dns/db.h>
  33 #include <dns/dispatch.h>
  34 #include <dns/events.h>
  35 #include <dns/message.h>
  36 #include <dns/rcode.h>
  37 #include <dns/resolver.h>
  38 #include <dns/rdata.h>
  39 #include <dns/rdataclass.h>
  40 #include <dns/rdatalist.h>
  41 #include <dns/rdataset.h>
  42 #include <dns/tsig.h>
  43 #include <dns/view.h>
  44 #include <dns/zone.h>
  45
  46 #include <named/interfacemgr.h>
  47 #include <named/log.h>
  48 #include <named/notify.h>
  49 #include <named/server.h>
  50 #include <named/update.h>
  51
  52 /***
  53  *** Client
  54  ***/
  55
  56 /*
  57  * Important note!
  58  *
  59  * All client state changes, other than that from idle to listening, occur
  60  * as a result of events.  This guarantees serialization and avoids the
  61  * need for locking.
  62  *
  63  * If a routine is ever created that allows someone other than the client's
  64  * task to change the client, then the client will have to be locked.
  65  */
  66
  67 #define NS_CLIENT_TRACE
  68 #ifdef NS_CLIENT_TRACE
  69 #define CTRACE(m)       ns_client_log(client, \
  70                                       NS_LOGCATEGORY_CLIENT, \
  71                                       NS_LOGMODULE_CLIENT, \
  72                                       ISC_LOG_DEBUG(3), \
  73                                       "%s", (m))
  74 #define MTRACE(m)       isc_log_write(ns_g_lctx, \
  75                                       NS_LOGCATEGORY_GENERAL, \
  76                                       NS_LOGMODULE_CLIENT, \
  77                                       ISC_LOG_DEBUG(3), \
  78                                       "clientmgr @%p: %s", manager, (m))
  79 #else
  80 #define CTRACE(m)       ((void)(m))
  81 #define MTRACE(m)       ((void)(m))
  82 #endif
  83
  84 #define TCP_CLIENT(c)   (((c)->attributes & NS_CLIENTATTR_TCP) != 0)
  85
  86 #define TCP_BUFFER_SIZE                 (65535 + 2)
  87 #define SEND_BUFFER_SIZE                4096
  88 #define RECV_BUFFER_SIZE                4096
  89
  90 struct ns_clientmgr {
  91         /* Unlocked. */
  92         unsigned int                    magic;
  93         isc_mem_t *                     mctx;
  94         isc_taskmgr_t *                 taskmgr;
  95         isc_timermgr_t *                timermgr;
  96         isc_mutex_t                     lock;
  97         /* Locked by lock. */
  98         isc_boolean_t                   exiting;
  99         client_list_t                   active;         /* Active clients */
 100         client_list_t                   recursing;      /* Recursing clients */
 101         client_list_t                   inactive;       /* To be recycled */
 102 };
 103
 104 #define MANAGER_MAGIC                   ISC_MAGIC('N', 'S', 'C', 'm')
 105 #define VALID_MANAGER(m)                ISC_MAGIC_VALID(m, MANAGER_MAGIC)
 106
 107 /*
 108  * Client object states.  Ordering is significant: higher-numbered
 109  * states are generally "more active", meaning that the client can
 110  * have more dynamically allocated data, outstanding events, etc.
 111  * In the list below, any such properties listed for state N
 112  * also apply to any state > N.
 113  *
 114  * To force the client into a less active state, set client->newstate
 115  * to that state and call exit_check().  This will cause any
 116  * activities defined for higher-numbered states to be aborted.
 117  */
 118
 119 #define NS_CLIENTSTATE_FREED    0
 120 /*
 121  * The client object no longer exists.
 122  */
 123
 124 #define NS_CLIENTSTATE_INACTIVE 1
 125 /*
 126  * The client object exists and has a task and timer.
 127  * Its "query" struct and sendbuf are initialized.
 128  * It is on the client manager's list of inactive clients.
 129  * It has a message and OPT, both in the reset state.
 130  */
 131
 132 #define NS_CLIENTSTATE_READY    2
 133 /*
 134  * The client object is either a TCP or a UDP one, and
 135  * it is associated with a network interface.  It is on the
 136  * client manager's list of active clients.
 137  *
 138  * If it is a TCP client object, it has a TCP listener socket
 139  * and an outstanding TCP listen request.
 140  *
 141  * If it is a UDP client object, it has a UDP listener socket
 142  * and an outstanding UDP receive request.
 143  */
 144
 145 #define NS_CLIENTSTATE_READING  3
 146 /*
 147  * The client object is a TCP client object that has received
 148  * a connection.  It has a tcpsocket, tcpmsg, TCP quota, and an
 149  * outstanding TCP read request.  This state is not used for
 150  * UDP client objects.
 151  */
 152
 153 #define NS_CLIENTSTATE_WORKING  4
 154 /*
 155  * The client object has received a request and is working
 156  * on it.  It has a view, and it may have any of a non-reset OPT,
 157  * recursion quota, and an outstanding write request.
 158  */
 159
 160 #define NS_CLIENTSTATE_MAX      9
 161 /*
 162  * Sentinel value used to indicate "no state".  When client->newstate
 163  * has this value, we are not attempting to exit the current state.
 164  * Must be greater than any valid state.
 165  */
 166
 167 /*
 168  * Enable ns_client_dropport() by default.
 169  */
 170 #ifndef NS_CLIENT_DROPPORT
 171 #define NS_CLIENT_DROPPORT 1
 172 #endif
 173
 174 static void client_read(ns_client_t *client);
 175 static void client_accept(ns_client_t *client);
 176 static void client_udprecv(ns_client_t *client);
 177 static void clientmgr_destroy(ns_clientmgr_t *manager);
 178 static isc_boolean_t exit_check(ns_client_t *client);
 179 static void ns_client_endrequest(ns_client_t *client);
 180 static void ns_client_checkactive(ns_client_t *client);
 181 static void client_start(isc_task_t *task, isc_event_t *event);
 182 static void client_request(isc_task_t *task, isc_event_t *event);
 183 static void ns_client_dumpmessage(ns_client_t *client, const char *reason);
 184
 185 void
 186 ns_client_recursing(ns_client_t *client) {
 187         REQUIRE(NS_CLIENT_VALID(client));
 188
 189         LOCK(&client->manager->lock);
 190         ISC_LIST_UNLINK(*client->list, client, link);
 191         ISC_LIST_APPEND(client->manager->recursing, client, link);
 192         client->list = &client->manager->recursing;
 193         UNLOCK(&client->manager->lock);
 194 }
 195
 196 void
 197 ns_client_killoldestquery(ns_client_t *client) {
 198         ns_client_t *oldest;
 199         REQUIRE(NS_CLIENT_VALID(client));
 200
 201         LOCK(&client->manager->lock);
 202         oldest = ISC_LIST_HEAD(client->manager->recursing);
 203         if (oldest != NULL) {
 204                 ns_query_cancel(oldest);
 205                 ISC_LIST_UNLINK(*oldest->list, oldest, link);
 206                 ISC_LIST_APPEND(client->manager->active, oldest, link);
 207                 oldest->list = &client->manager->active;
 208         }
 209         UNLOCK(&client->manager->lock);
 210 }
 211
 212 void
 213 ns_client_settimeout(ns_client_t *client, unsigned int seconds) {
 214         isc_result_t result;
 215         isc_interval_t interval;
 216
 217         isc_interval_set(&interval, seconds, 0);
 218         result = isc_timer_reset(client->timer, isc_timertype_once, NULL,
 219                                  &interval, ISC_FALSE);
 220         client->timerset = ISC_TRUE;
 221         if (result != ISC_R_SUCCESS) {
 222                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
 223                               NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
 224                               "setting timeout: %s",
 225                               isc_result_totext(result));
 226                 /* Continue anyway. */
 227         }
 228 }
 229
 230 /*
 231  * Check for a deactivation or shutdown request and take appropriate
 232  * action.  Returns ISC_TRUE if either is in progress; in this case
 233  * the caller must no longer use the client object as it may have been
 234  * freed.
 235  */
 236 static isc_boolean_t
 237 exit_check(ns_client_t *client) {
 238         ns_clientmgr_t *locked_manager = NULL;
 239         ns_clientmgr_t *destroy_manager = NULL;
 240
 241         REQUIRE(NS_CLIENT_VALID(client));
 242
 243         if (client->state <= client->newstate)
 244                 return (ISC_FALSE); /* Business as usual. */
 245
 246         INSIST(client->newstate < NS_CLIENTSTATE_WORKING);
 247
 248         /*
 249          * We need to detach from the view early when shutting down
 250          * the server to break the following vicious circle:
 251          *
 252          *  - The resolver will not shut down until the view refcount is zero
 253          *  - The view refcount does not go to zero until all clients detach
 254          *  - The client does not detach from the view until references is zero
 255          *  - references does not go to zero until the resolver has shut down
 256          *
 257          * Keep the view attached until any outstanding updates complete.
 258          */
 259         if (client->nupdates == 0 &&
 260             client->newstate == NS_CLIENTSTATE_FREED && client->view != NULL)
 261                 dns_view_detach(&client->view);
 262
 263         if (client->state == NS_CLIENTSTATE_WORKING) {
 264                 INSIST(client->newstate <= NS_CLIENTSTATE_READING);
 265                 /*
 266                  * Let the update processing complete.
 267                  */
 268                 if (client->nupdates > 0)
 269                         return (ISC_TRUE);
 270                 /*
 271                  * We are trying to abort request processing.
 272                  */
 273                 if (client->nsends > 0) {
 274                         isc_socket_t *socket;
 275                         if (TCP_CLIENT(client))
 276                                 socket = client->tcpsocket;
 277                         else
 278                                 socket = client->udpsocket;
 279                         isc_socket_cancel(socket, client->task,
 280                                           ISC_SOCKCANCEL_SEND);
 281                 }
 282
 283                 if (! (client->nsends == 0 && client->nrecvs == 0 &&
 284                        client->references == 0))
 285                 {
 286                         /*
 287                          * Still waiting for I/O cancel completion.
 288                          * or lingering references.
 289                          */
 290                         return (ISC_TRUE);
 291                 }
 292                 /*
 293                  * I/O cancel is complete.  Burn down all state
 294                  * related to the current request.  Ensure that
 295                  * the client is on the active list and not the
 296                  * recursing list.
 297                  */
 298                 LOCK(&client->manager->lock);
 299                 if (client->list == &client->manager->recursing) {
 300                         ISC_LIST_UNLINK(*client->list, client, link);
 301                         ISC_LIST_APPEND(client->manager->active, client, link);
 302                         client->list = &client->manager->active;
 303                 }
 304                 UNLOCK(&client->manager->lock);
 305                 ns_client_endrequest(client);
 306
 307                 client->state = NS_CLIENTSTATE_READING;
 308                 INSIST(client->recursionquota == NULL);
 309                 if (NS_CLIENTSTATE_READING == client->newstate) {
 310                         client_read(client);
 311                         client->newstate = NS_CLIENTSTATE_MAX;
 312                         return (ISC_TRUE); /* We're done. */
 313                 }
 314         }
 315
 316         if (client->state == NS_CLIENTSTATE_READING) {
 317                 /*
 318                  * We are trying to abort the current TCP connection,
 319                  * if any.
 320                  */
 321                 INSIST(client->recursionquota == NULL);
 322                 INSIST(client->newstate <= NS_CLIENTSTATE_READY);
 323                 if (client->nreads > 0)
 324                         dns_tcpmsg_cancelread(&client->tcpmsg);
 325                 if (! client->nreads == 0) {
 326                         /* Still waiting for read cancel completion. */
 327                         return (ISC_TRUE);
 328                 }
 329
 330                 if (client->tcpmsg_valid) {
 331                         dns_tcpmsg_invalidate(&client->tcpmsg);
 332                         client->tcpmsg_valid = ISC_FALSE;
 333                 }
 334                 if (client->tcpsocket != NULL) {
 335                         CTRACE("closetcp");
 336                         isc_socket_detach(&client->tcpsocket);
 337                 }
 338
 339                 if (client->tcpquota != NULL)
 340                         isc_quota_detach(&client->tcpquota);
 341
 342                 if (client->timerset) {
 343                         (void)isc_timer_reset(client->timer,
 344                                               isc_timertype_inactive,
 345                                               NULL, NULL, ISC_TRUE);
 346                         client->timerset = ISC_FALSE;
 347                 }
 348
 349                 client->peeraddr_valid = ISC_FALSE;
 350
 351                 client->state = NS_CLIENTSTATE_READY;
 352                 INSIST(client->recursionquota == NULL);
 353
 354                 /*
 355                  * Now the client is ready to accept a new TCP connection
 356                  * or UDP request, but we may have enough clients doing
 357                  * that already.  Check whether this client needs to remain
 358                  * active and force it to go inactive if not.
 359                  */
 360                 ns_client_checkactive(client);
 361
 362                 if (NS_CLIENTSTATE_READY == client->newstate) {
 363                         if (TCP_CLIENT(client)) {
 364                                 client_accept(client);
 365                         } else
 366                                 client_udprecv(client);
 367                         client->newstate = NS_CLIENTSTATE_MAX;
 368                         return (ISC_TRUE);
 369                 }
 370         }
 371
 372         if (client->state == NS_CLIENTSTATE_READY) {
 373                 INSIST(client->newstate <= NS_CLIENTSTATE_INACTIVE);
 374                 /*
 375                  * We are trying to enter the inactive state.
 376                  */
 377                 if (client->naccepts > 0)
 378                         isc_socket_cancel(client->tcplistener, client->task,
 379                                           ISC_SOCKCANCEL_ACCEPT);
 380
 381                 if (! (client->naccepts == 0)) {
 382                         /* Still waiting for accept cancel completion. */
 383                         return (ISC_TRUE);
 384                 }
 385                 /* Accept cancel is complete. */
 386
 387                 if (client->nrecvs > 0)
 388                         isc_socket_cancel(client->udpsocket, client->task,
 389                                           ISC_SOCKCANCEL_RECV);
 390                 if (! (client->nrecvs == 0)) {
 391                         /* Still waiting for recv cancel completion. */
 392                         return (ISC_TRUE);
 393                 }
 394                 /* Recv cancel is complete. */
 395
 396                 if (client->nctls > 0) {
 397                         /* Still waiting for control event to be delivered */
 398                         return (ISC_TRUE);
 399                 }
 400
 401                 /* Deactivate the client. */
 402                 if (client->interface)
 403                         ns_interface_detach(&client->interface);
 404
 405                 INSIST(client->naccepts == 0);
 406                 INSIST(client->recursionquota == NULL);
 407                 if (client->tcplistener != NULL)
 408                         isc_socket_detach(&client->tcplistener);
 409
 410                 if (client->udpsocket != NULL)
 411                         isc_socket_detach(&client->udpsocket);
 412
 413                 if (client->dispatch != NULL)
 414                         dns_dispatch_detach(&client->dispatch);
 415
 416                 client->attributes = 0;
 417                 client->mortal = ISC_FALSE;
 418
 419                 LOCK(&client->manager->lock);
 420                 /*
 421                  * Put the client on the inactive list.  If we are aiming for
 422                  * the "freed" state, it will be removed from the inactive
 423                  * list shortly, and we need to keep the manager locked until
 424                  * that has been done, lest the manager decide to reactivate
 425                  * the dying client inbetween.
 426                  */
 427                 locked_manager = client->manager;
 428                 ISC_LIST_UNLINK(*client->list, client, link);
 429                 ISC_LIST_APPEND(client->manager->inactive, client, link);
 430                 client->list = &client->manager->inactive;
 431                 client->state = NS_CLIENTSTATE_INACTIVE;
 432                 INSIST(client->recursionquota == NULL);
 433
 434                 if (client->state == client->newstate) {
 435                         client->newstate = NS_CLIENTSTATE_MAX;
 436                         goto unlock;
 437                 }
 438         }
 439
 440         if (client->state == NS_CLIENTSTATE_INACTIVE) {
 441                 INSIST(client->newstate == NS_CLIENTSTATE_FREED);
 442                 /*
 443                  * We are trying to free the client.
 444                  *
 445                  * When "shuttingdown" is true, either the task has received
 446                  * its shutdown event or no shutdown event has ever been
 447                  * set up.  Thus, we have no outstanding shutdown
 448                  * event at this point.
 449                  */
 450                 REQUIRE(client->state == NS_CLIENTSTATE_INACTIVE);
 451
 452                 INSIST(client->recursionquota == NULL);
 453
 454                 ns_query_free(client);
 455                 isc_mem_put(client->mctx, client->recvbuf, RECV_BUFFER_SIZE);
 456                 isc_event_free((isc_event_t **)&client->sendevent);
 457                 isc_event_free((isc_event_t **)&client->recvevent);
 458                 isc_timer_detach(&client->timer);
 459
 460                 if (client->tcpbuf != NULL)
 461                         isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
 462                 if (client->opt != NULL) {
 463                         INSIST(dns_rdataset_isassociated(client->opt));
 464                         dns_rdataset_disassociate(client->opt);
 465                         dns_message_puttemprdataset(client->message, &client->opt);
 466                 }
 467                 dns_message_destroy(&client->message);
 468                 if (client->manager != NULL) {
 469                         ns_clientmgr_t *manager = client->manager;
 470                         if (locked_manager == NULL) {
 471                                 LOCK(&manager->lock);
 472                                 locked_manager = manager;
 473                         }
 474                         ISC_LIST_UNLINK(*client->list, client, link);
 475                         client->list = NULL;
 476                         if (manager->exiting &&
 477                             ISC_LIST_EMPTY(manager->active) &&
 478                             ISC_LIST_EMPTY(manager->inactive) &&
 479                             ISC_LIST_EMPTY(manager->recursing))
 480                                 destroy_manager = manager;
 481                 }
 482                 /*
 483                  * Detaching the task must be done after unlinking from
 484                  * the manager's lists because the manager accesses
 485                  * client->task.
 486                  */
 487                 if (client->task != NULL)
 488                         isc_task_detach(&client->task);
 489
 490                 CTRACE("free");
 491                 client->magic = 0;
 492                 isc_mem_put(client->mctx, client, sizeof(*client));
 493
 494                 goto unlock;
 495         }
 496
 497  unlock:
 498         if (locked_manager != NULL) {
 499                 UNLOCK(&locked_manager->lock);
 500                 locked_manager = NULL;
 501         }
 502
 503         /*
 504          * Only now is it safe to destroy the client manager (if needed),
 505          * because we have accessed its lock for the last time.
 506          */
 507         if (destroy_manager != NULL)
 508                 clientmgr_destroy(destroy_manager);
 509
 510         return (ISC_TRUE);
 511 }
 512
 513 /*
 514  * The client's task has received the client's control event
 515  * as part of the startup process.
 516  */
 517 static void
 518 client_start(isc_task_t *task, isc_event_t *event) {
 519         ns_client_t *client = (ns_client_t *) event->ev_arg;
 520
 521         INSIST(task == client->task);
 522
 523         UNUSED(task);
 524
 525         INSIST(client->nctls == 1);
 526         client->nctls--;
 527
 528         if (exit_check(client))
 529                 return;
 530
 531         if (TCP_CLIENT(client)) {
 532                 client_accept(client);
 533         } else {
 534                 client_udprecv(client);
 535         }
 536 }
 537
 538
 539 /*
 540  * The client's task has received a shutdown event.
 541  */
 542 static void
 543 client_shutdown(isc_task_t *task, isc_event_t *event) {
 544         ns_client_t *client;
 545
 546         REQUIRE(event != NULL);
 547         REQUIRE(event->ev_type == ISC_TASKEVENT_SHUTDOWN);
 548         client = event->ev_arg;
 549         REQUIRE(NS_CLIENT_VALID(client));
 550         REQUIRE(task == client->task);
 551
 552         UNUSED(task);
 553
 554         CTRACE("shutdown");
 555
 556         isc_event_free(&event);
 557
 558         if (client->shutdown != NULL) {
 559                 (client->shutdown)(client->shutdown_arg, ISC_R_SHUTTINGDOWN);
 560                 client->shutdown = NULL;
 561                 client->shutdown_arg = NULL;
 562         }
 563
 564         client->newstate = NS_CLIENTSTATE_FREED;
 565         (void)exit_check(client);
 566 }
 567
 568 static void
 569 ns_client_endrequest(ns_client_t *client) {
 570         INSIST(client->naccepts == 0);
 571         INSIST(client->nreads == 0);
 572         INSIST(client->nsends == 0);
 573         INSIST(client->nrecvs == 0);
 574         INSIST(client->nupdates == 0);
 575         INSIST(client->state == NS_CLIENTSTATE_WORKING);
 576
 577         CTRACE("endrequest");
 578
 579         if (client->next != NULL) {
 580                 (client->next)(client);
 581                 client->next = NULL;
 582         }
 583
 584         if (client->view != NULL)
 585                 dns_view_detach(&client->view);
 586         if (client->opt != NULL) {
 587                 INSIST(dns_rdataset_isassociated(client->opt));
 588                 dns_rdataset_disassociate(client->opt);
 589                 dns_message_puttemprdataset(client->message, &client->opt);
 590         }
 591
 592         client->udpsize = 512;
 593         client->extflags = 0;
 594         dns_message_reset(client->message, DNS_MESSAGE_INTENTPARSE);
 595
 596         if (client->recursionquota != NULL)
 597                 isc_quota_detach(&client->recursionquota);
 598
 599         /*
 600          * Clear all client attributes that are specific to
 601          * the request; that's all except the TCP flag.
 602          */
 603         client->attributes &= NS_CLIENTATTR_TCP;
 604 }
 605
 606 static void
 607 ns_client_checkactive(ns_client_t *client) {
 608         if (client->mortal) {
 609                 /*
 610                  * This client object should normally go inactive
 611                  * at this point, but if we have fewer active client
 612                  * objects than  desired due to earlier quota exhaustion,
 613                  * keep it active to make up for the shortage.
 614                  */
 615                 isc_boolean_t need_another_client = ISC_FALSE;
 616                 if (TCP_CLIENT(client)) {
 617                         LOCK(&client->interface->lock);
 618                         if (client->interface->ntcpcurrent <
 619                             client->interface->ntcptarget)
 620                                 need_another_client = ISC_TRUE;
 621                         UNLOCK(&client->interface->lock);
 622                 } else {
 623                         /*
 624                          * The UDP client quota is enforced by making
 625                          * requests fail rather than by not listening
 626                          * for new ones.  Therefore, there is always a
 627                          * full set of UDP clients listening.
 628                          */
 629                 }
 630                 if (! need_another_client) {
 631                         /*
 632                          * We don't need this client object.  Recycle it.
 633                          */
 634                         if (client->newstate >= NS_CLIENTSTATE_INACTIVE)
 635                                 client->newstate = NS_CLIENTSTATE_INACTIVE;
 636                 }
 637         }
 638 }
 639
 640 void
 641 ns_client_next(ns_client_t *client, isc_result_t result) {
 642         int newstate;
 643
 644         REQUIRE(NS_CLIENT_VALID(client));
 645         REQUIRE(client->state == NS_CLIENTSTATE_WORKING ||
 646                 client->state == NS_CLIENTSTATE_READING);
 647
 648         CTRACE("next");
 649
 650         if (result != ISC_R_SUCCESS)
 651                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
 652                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
 653                               "request failed: %s", isc_result_totext(result));
 654
 655         /*
 656          * An error processing a TCP request may have left
 657          * the connection out of sync.  To be safe, we always
 658          * sever the connection when result != ISC_R_SUCCESS.
 659          */
 660         if (result == ISC_R_SUCCESS && TCP_CLIENT(client))
 661                 newstate = NS_CLIENTSTATE_READING;
 662         else
 663                 newstate = NS_CLIENTSTATE_READY;
 664
 665         if (client->newstate > newstate)
 666                 client->newstate = newstate;
 667         (void)exit_check(client);
 668 }
 669
 670
 671 static void
 672 client_senddone(isc_task_t *task, isc_event_t *event) {
 673         ns_client_t *client;
 674         isc_socketevent_t *sevent = (isc_socketevent_t *) event;
 675
 676         REQUIRE(sevent != NULL);
 677         REQUIRE(sevent->ev_type == ISC_SOCKEVENT_SENDDONE);
 678         client = sevent->ev_arg;
 679         REQUIRE(NS_CLIENT_VALID(client));
 680         REQUIRE(task == client->task);
 681         REQUIRE(sevent == client->sendevent);
 682
 683         UNUSED(task);
 684
 685         CTRACE("senddone");
 686
 687         if (sevent->result != ISC_R_SUCCESS)
 688                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
 689                               NS_LOGMODULE_CLIENT, ISC_LOG_WARNING,
 690                               "error sending response: %s",
 691                               isc_result_totext(sevent->result));
 692
 693         INSIST(client->nsends > 0);
 694         client->nsends--;
 695
 696         if (client->tcpbuf != NULL) {
 697                 INSIST(TCP_CLIENT(client));
 698                 isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
 699                 client->tcpbuf = NULL;
 700         }
 701
 702         if (exit_check(client))
 703                 return;
 704
 705         ns_client_next(client, ISC_R_SUCCESS);
 706 }
 707
 708 /*
 709  * We only want to fail with ISC_R_NOSPACE when called from
 710  * ns_client_sendraw() and not when called from ns_client_send(),
 711  * tcpbuffer is NULL when called from ns_client_sendraw() and
 712  * length != 0.  tcpbuffer != NULL when called from ns_client_send()
 713  * and length == 0.
 714  */
 715
 716 static isc_result_t
 717 client_allocsendbuf(ns_client_t *client, isc_buffer_t *buffer,
 718                     isc_buffer_t *tcpbuffer, isc_uint32_t length,
 719                     unsigned char *sendbuf, unsigned char **datap)
 720 {
 721         unsigned char *data;
 722         isc_uint32_t bufsize;
 723         isc_result_t result;
 724
 725         INSIST(datap != NULL);
 726         INSIST((tcpbuffer == NULL && length != 0) ||
 727                (tcpbuffer != NULL && length == 0));
 728
 729         if (TCP_CLIENT(client)) {
 730                 INSIST(client->tcpbuf == NULL);
 731                 if (length + 2 > TCP_BUFFER_SIZE) {
 732                         result = ISC_R_NOSPACE;
 733                         goto done;
 734                 }
 735                 client->tcpbuf = isc_mem_get(client->mctx, TCP_BUFFER_SIZE);
 736                 if (client->tcpbuf == NULL) {
 737                         result = ISC_R_NOMEMORY;
 738                         goto done;
 739                 }
 740                 data = client->tcpbuf;
 741                 if (tcpbuffer != NULL) {
 742                         isc_buffer_init(tcpbuffer, data, TCP_BUFFER_SIZE);
 743                         isc_buffer_init(buffer, data + 2, TCP_BUFFER_SIZE - 2);
 744                 } else {
 745                         isc_buffer_init(buffer, data, TCP_BUFFER_SIZE);
 746                         INSIST(length <= 0xffff);
 747                         isc_buffer_putuint16(buffer, (isc_uint16_t)length);
 748                 }
 749         } else {
 750                 data = sendbuf;
 751                 if (client->udpsize < SEND_BUFFER_SIZE)
 752                         bufsize = client->udpsize;
 753                 else
 754                         bufsize = SEND_BUFFER_SIZE;
 755                 if (length > bufsize) {
 756                         result = ISC_R_NOSPACE;
 757                         goto done;
 758                 }
 759                 isc_buffer_init(buffer, data, bufsize);
 760         }
 761         *datap = data;
 762         result = ISC_R_SUCCESS;
 763
 764  done:
 765         return (result);
 766 }
 767
 768 static isc_result_t
 769 client_sendpkg(ns_client_t *client, isc_buffer_t *buffer) {
 770         struct in6_pktinfo *pktinfo;
 771         isc_result_t result;
 772         isc_region_t r;
 773         isc_sockaddr_t *address;
 774         isc_socket_t *socket;
 775         isc_netaddr_t netaddr;
 776         int match;
 777         unsigned int sockflags = ISC_SOCKFLAG_IMMEDIATE;
 778
 779         if (TCP_CLIENT(client)) {
 780                 socket = client->tcpsocket;
 781                 address = NULL;
 782         } else {
 783                 socket = client->udpsocket;
 784                 address = &client->peeraddr;
 785
 786                 isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
 787                 if (ns_g_server->blackholeacl != NULL &&
 788                     dns_acl_match(&netaddr, NULL,
 789                                   ns_g_server->blackholeacl,
 790                                   &ns_g_server->aclenv,
 791                                   &match, NULL) == ISC_R_SUCCESS &&
 792                     match > 0)
 793                         return (DNS_R_BLACKHOLED);
 794                 sockflags |= ISC_SOCKFLAG_NORETRY;
 795         }
 796
 797         if ((client->attributes & NS_CLIENTATTR_PKTINFO) != 0 &&
 798             (client->attributes & NS_CLIENTATTR_MULTICAST) == 0)
 799                 pktinfo = &client->pktinfo;
 800         else
 801                 pktinfo = NULL;
 802
 803         isc_buffer_usedregion(buffer, &r);
 804
 805         CTRACE("sendto");
 806
 807         result = isc_socket_sendto2(socket, &r, client->task,
 808                                     address, pktinfo,
 809                                     client->sendevent, sockflags);
 810         if (result == ISC_R_SUCCESS || result == ISC_R_INPROGRESS) {
 811                 client->nsends++;
 812                 if (result == ISC_R_SUCCESS)
 813                         client_senddone(client->task,
 814                                         (isc_event_t *)client->sendevent);
 815                 result = ISC_R_SUCCESS;
 816         }
 817         return (result);
 818 }
 819
 820 void
 821 ns_client_sendraw(ns_client_t *client, dns_message_t *message) {
 822         isc_result_t result;
 823         unsigned char *data;
 824         isc_buffer_t buffer;
 825         isc_region_t r;
 826         isc_region_t *mr;
 827         unsigned char sendbuf[SEND_BUFFER_SIZE];
 828
 829         REQUIRE(NS_CLIENT_VALID(client));
 830
 831         CTRACE("sendraw");
 832
 833         mr = dns_message_getrawmessage(message);
 834         if (mr == NULL) {
 835                 result = ISC_R_UNEXPECTEDEND;
 836                 goto done;
 837         }
 838
 839         result = client_allocsendbuf(client, &buffer, NULL, mr->length,
 840                                      sendbuf, &data);
 841         if (result != ISC_R_SUCCESS)
 842                 goto done;
 843
 844         /*
 845          * Copy message to buffer and fixup id.
 846          */
 847         isc_buffer_availableregion(&buffer, &r);
 848         result = isc_buffer_copyregion(&buffer, mr);
 849         if (result != ISC_R_SUCCESS)
 850                 goto done;
 851         r.base[0] = (client->message->id >> 8) & 0xff;
 852         r.base[1] = client->message->id & 0xff;
 853
 854         result = client_sendpkg(client, &buffer);
 855         if (result == ISC_R_SUCCESS)
 856                 return;
 857
 858  done:
 859         if (client->tcpbuf != NULL) {
 860                 isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
 861                 client->tcpbuf = NULL;
 862         }
 863         ns_client_next(client, result);
 864 }
 865
 866 void
 867 ns_client_send(ns_client_t *client) {
 868         isc_result_t result;
 869         unsigned char *data;
 870         isc_buffer_t buffer;
 871         isc_buffer_t tcpbuffer;
 872         isc_region_t r;
 873         dns_compress_t cctx;
 874         isc_boolean_t cleanup_cctx = ISC_FALSE;
 875         unsigned char sendbuf[SEND_BUFFER_SIZE];
 876         unsigned int dnssec_opts;
 877         unsigned int preferred_glue;
 878
 879         REQUIRE(NS_CLIENT_VALID(client));
 880
 881         CTRACE("send");
 882
 883         if ((client->attributes & NS_CLIENTATTR_RA) != 0)
 884                 client->message->flags |= DNS_MESSAGEFLAG_RA;
 885
 886         if ((client->attributes & NS_CLIENTATTR_WANTDNSSEC) != 0)
 887                 dnssec_opts = 0;
 888         else
 889                 dnssec_opts = DNS_MESSAGERENDER_OMITDNSSEC;
 890
 891         preferred_glue = 0;
 892         if (client->view != NULL) {
 893                 if (client->view->preferred_glue == dns_rdatatype_a)
 894                         preferred_glue = DNS_MESSAGERENDER_PREFER_A;
 895                 else if (client->view->preferred_glue == dns_rdatatype_aaaa)
 896                         preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
 897         }
 898
 899         /*
 900          * XXXRTH  The following doesn't deal with TCP buffer resizing.
 901          */
 902         result = client_allocsendbuf(client, &buffer, &tcpbuffer, 0,
 903                                      sendbuf, &data);
 904         if (result != ISC_R_SUCCESS)
 905                 goto done;
 906
 907         result = dns_compress_init(&cctx, -1, client->mctx);
 908         if (result != ISC_R_SUCCESS)
 909                 goto done;
 910         cleanup_cctx = ISC_TRUE;
 911
 912         result = dns_message_renderbegin(client->message, &cctx, &buffer);
 913         if (result != ISC_R_SUCCESS)
 914                 goto done;
 915         if (client->opt != NULL) {
 916                 result = dns_message_setopt(client->message, client->opt);
 917                 /*
 918                  * XXXRTH dns_message_setopt() should probably do this...
 919                  */
 920                 client->opt = NULL;
 921                 if (result != ISC_R_SUCCESS)
 922                         goto done;
 923         }
 924         result = dns_message_rendersection(client->message,
 925                                            DNS_SECTION_QUESTION, 0);
 926         if (result == ISC_R_NOSPACE) {
 927                 client->message->flags |= DNS_MESSAGEFLAG_TC;
 928                 goto renderend;
 929         }
 930         if (result != ISC_R_SUCCESS)
 931                 goto done;
 932         result = dns_message_rendersection(client->message,
 933                                            DNS_SECTION_ANSWER,
 934                                            DNS_MESSAGERENDER_PARTIAL |
 935                                            dnssec_opts);
 936         if (result == ISC_R_NOSPACE) {
 937                 client->message->flags |= DNS_MESSAGEFLAG_TC;
 938                 goto renderend;
 939         }
 940         if (result != ISC_R_SUCCESS)
 941                 goto done;
 942         result = dns_message_rendersection(client->message,
 943                                            DNS_SECTION_AUTHORITY,
 944                                            DNS_MESSAGERENDER_PARTIAL |
 945                                            dnssec_opts);
 946         if (result == ISC_R_NOSPACE) {
 947                 client->message->flags |= DNS_MESSAGEFLAG_TC;
 948                 goto renderend;
 949         }
 950         if (result != ISC_R_SUCCESS)
 951                 goto done;
 952         result = dns_message_rendersection(client->message,
 953                                            DNS_SECTION_ADDITIONAL,
 954                                            preferred_glue | dnssec_opts);
 955         if (result != ISC_R_SUCCESS && result != ISC_R_NOSPACE)
 956                 goto done;
 957  renderend:
 958         result = dns_message_renderend(client->message);
 959
 960         if (result != ISC_R_SUCCESS)
 961                 goto done;
 962
 963         if (cleanup_cctx) {
 964                 dns_compress_invalidate(&cctx);
 965                 cleanup_cctx = ISC_FALSE;
 966         }
 967
 968         if (TCP_CLIENT(client)) {
 969                 isc_buffer_usedregion(&buffer, &r);
 970                 isc_buffer_putuint16(&tcpbuffer, (isc_uint16_t) r.length);
 971                 isc_buffer_add(&tcpbuffer, r.length);
 972                 result = client_sendpkg(client, &tcpbuffer);
 973         } else
 974                 result = client_sendpkg(client, &buffer);
 975         if (result == ISC_R_SUCCESS)
 976                 return;
 977
 978  done:
 979         if (client->tcpbuf != NULL) {
 980                 isc_mem_put(client->mctx, client->tcpbuf, TCP_BUFFER_SIZE);
 981                 client->tcpbuf = NULL;
 982         }
 983
 984         if (cleanup_cctx)
 985                 dns_compress_invalidate(&cctx);
 986
 987         ns_client_next(client, result);
 988 }
 989
 990 #if NS_CLIENT_DROPPORT
 991 #define DROPPORT_NO             0
 992 #define DROPPORT_REQUEST        1
 993 #define DROPPORT_RESPONSE       2
 994 /*%
 995  * ns_client_dropport determines if certain requests / responses
 996  * should be dropped based on the port number.
 997  *
 998  * Returns:
 999  * \li  0:      Don't drop.
1000  * \li  1:      Drop request.
1001  * \li  2:      Drop (error) response.
1002  */
1003 static int
1004 ns_client_dropport(in_port_t port) {
1005         switch (port) {
1006         case 7: /* echo */
1007         case 13: /* daytime */
1008         case 19: /* chargen */
1009         case 37: /* time */
1010                 return (DROPPORT_REQUEST);
1011         case 464: /* kpasswd */
1012                 return (DROPPORT_RESPONSE);
1013         }
1014         return (DROPPORT_NO);
1015 }
1016 #endif
1017
1018 void
1019 ns_client_error(ns_client_t *client, isc_result_t result) {
1020         dns_rcode_t rcode;
1021         dns_message_t *message;
1022
1023         REQUIRE(NS_CLIENT_VALID(client));
1024
1025         CTRACE("error");
1026
1027         message = client->message;
1028         rcode = dns_result_torcode(result);
1029
1030 #if NS_CLIENT_DROPPORT
1031         /*
1032          * Don't send FORMERR to ports on the drop port list.
1033          */
1034         if (rcode == dns_rcode_formerr &&
1035             ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) !=
1036             DROPPORT_NO) {
1037                 char buf[64];
1038                 isc_buffer_t b;
1039
1040                 isc_buffer_init(&b, buf, sizeof(buf) - 1);
1041                 if (dns_rcode_totext(rcode, &b) != ISC_R_SUCCESS)
1042                         isc_buffer_putstr(&b, "UNKNOWN RCODE");
1043                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1044                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
1045                               "dropped error (%.*s) response: suspicious port",
1046                               (int)isc_buffer_usedlength(&b), buf);
1047                 ns_client_next(client, ISC_R_SUCCESS);
1048                 return;
1049         }
1050 #endif
1051
1052         /*
1053          * Message may be an in-progress reply that we had trouble
1054          * with, in which case QR will be set.  We need to clear QR before
1055          * calling dns_message_reply() to avoid triggering an assertion.
1056          */
1057         message->flags &= ~DNS_MESSAGEFLAG_QR;
1058         /*
1059          * AA and AD shouldn't be set.
1060          */
1061         message->flags &= ~(DNS_MESSAGEFLAG_AA | DNS_MESSAGEFLAG_AD);
1062         result = dns_message_reply(message, ISC_TRUE);
1063         if (result != ISC_R_SUCCESS) {
1064                 /*
1065                  * It could be that we've got a query with a good header,
1066                  * but a bad question section, so we try again with
1067                  * want_question_section set to ISC_FALSE.
1068                  */
1069                 result = dns_message_reply(message, ISC_FALSE);
1070                 if (result != ISC_R_SUCCESS) {
1071                         ns_client_next(client, result);
1072                         return;
1073                 }
1074         }
1075         message->rcode = rcode;
1076
1077         /*
1078          * FORMERR loop avoidance:  If we sent a FORMERR message
1079          * with the same ID to the same client less than two
1080          * seconds ago, assume that we are in an infinite error
1081          * packet dialog with a server for some protocol whose
1082          * error responses look enough like DNS queries to
1083          * elicit a FORMERR response.  Drop a packet to break
1084          * the loop.
1085          */
1086         if (rcode == dns_rcode_formerr) {
1087                 if (isc_sockaddr_equal(&client->peeraddr,
1088                                        &client->formerrcache.addr) &&
1089                     message->id == client->formerrcache.id &&
1090                     client->requesttime - client->formerrcache.time < 2) {
1091                         /* Drop packet. */
1092                         ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1093                                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
1094                                       "possible error packet loop, "
1095                                       "FORMERR dropped");
1096                         ns_client_next(client, result);
1097                         return;
1098                 }
1099                 client->formerrcache.addr = client->peeraddr;
1100                 client->formerrcache.time = client->requesttime;
1101                 client->formerrcache.id = message->id;
1102         }
1103         ns_client_send(client);
1104 }
1105
1106 static inline isc_result_t
1107 client_addopt(ns_client_t *client) {
1108         dns_rdataset_t *rdataset;
1109         dns_rdatalist_t *rdatalist;
1110         dns_rdata_t *rdata;
1111         isc_result_t result;
1112         dns_view_t *view;
1113         dns_resolver_t *resolver;
1114         isc_uint16_t udpsize;
1115
1116         REQUIRE(client->opt == NULL);   /* XXXRTH free old. */
1117
1118         rdatalist = NULL;
1119         result = dns_message_gettemprdatalist(client->message, &rdatalist);
1120         if (result != ISC_R_SUCCESS)
1121                 return (result);
1122         rdata = NULL;
1123         result = dns_message_gettemprdata(client->message, &rdata);
1124         if (result != ISC_R_SUCCESS)
1125                 return (result);
1126         rdataset = NULL;
1127         result = dns_message_gettemprdataset(client->message, &rdataset);
1128         if (result != ISC_R_SUCCESS)
1129                 return (result);
1130         dns_rdataset_init(rdataset);
1131
1132         rdatalist->type = dns_rdatatype_opt;
1133         rdatalist->covers = 0;
1134
1135         /*
1136          * Set the maximum UDP buffer size.
1137          */
1138         view = client->view;
1139         resolver = (view != NULL) ? view->resolver : NULL;
1140         if (resolver != NULL)
1141                 udpsize = dns_resolver_getudpsize(resolver);
1142         else
1143                 udpsize = ns_g_udpsize;
1144         rdatalist->rdclass = udpsize;
1145
1146         /*
1147          * Set EXTENDED-RCODE, VERSION and Z to 0.
1148          */
1149         rdatalist->ttl = (client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE);
1150
1151         /*
1152          * No ENDS options in the default case.
1153          */
1154         rdata->data = NULL;
1155         rdata->length = 0;
1156         rdata->rdclass = rdatalist->rdclass;
1157         rdata->type = rdatalist->type;
1158         rdata->flags = 0;
1159
1160         ISC_LIST_INIT(rdatalist->rdata);
1161         ISC_LIST_APPEND(rdatalist->rdata, rdata, link);
1162         RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist, rdataset)
1163                       == ISC_R_SUCCESS);
1164
1165         client->opt = rdataset;
1166
1167         return (ISC_R_SUCCESS);
1168 }
1169
1170 static inline isc_boolean_t
1171 allowed(isc_netaddr_t *addr, dns_name_t *signer, dns_acl_t *acl) {
1172         int match;
1173         isc_result_t result;
1174
1175         if (acl == NULL)
1176                 return (ISC_TRUE);
1177         result = dns_acl_match(addr, signer, acl, &ns_g_server->aclenv,
1178                                &match, NULL);
1179         if (result == ISC_R_SUCCESS && match > 0)
1180                 return (ISC_TRUE);
1181         return (ISC_FALSE);
1182 }
1183
1184 /*
1185  * Handle an incoming request event from the socket (UDP case)
1186  * or tcpmsg (TCP case).
1187  */
1188 static void
1189 client_request(isc_task_t *task, isc_event_t *event) {
1190         ns_client_t *client;
1191         isc_socketevent_t *sevent;
1192         isc_result_t result;
1193         isc_result_t sigresult = ISC_R_SUCCESS;
1194         isc_buffer_t *buffer;
1195         isc_buffer_t tbuffer;
1196         dns_view_t *view;
1197         dns_rdataset_t *opt;
1198         isc_boolean_t ra;       /* Recursion available. */
1199         isc_netaddr_t netaddr;
1200         isc_netaddr_t destaddr;
1201         int match;
1202         dns_messageid_t id;
1203         unsigned int flags;
1204         isc_boolean_t notimp;
1205
1206         REQUIRE(event != NULL);
1207         client = event->ev_arg;
1208         REQUIRE(NS_CLIENT_VALID(client));
1209         REQUIRE(task == client->task);
1210
1211         INSIST(client->recursionquota == NULL);
1212
1213         INSIST(client->state ==
1214                TCP_CLIENT(client) ?
1215                NS_CLIENTSTATE_READING :
1216                NS_CLIENTSTATE_READY);
1217
1218         if (event->ev_type == ISC_SOCKEVENT_RECVDONE) {
1219                 INSIST(!TCP_CLIENT(client));
1220                 sevent = (isc_socketevent_t *)event;
1221                 REQUIRE(sevent == client->recvevent);
1222                 isc_buffer_init(&tbuffer, sevent->region.base, sevent->n);
1223                 isc_buffer_add(&tbuffer, sevent->n);
1224                 buffer = &tbuffer;
1225                 result = sevent->result;
1226                 if (result == ISC_R_SUCCESS) {
1227                         client->peeraddr = sevent->address;
1228                         client->peeraddr_valid = ISC_TRUE;
1229                 }
1230                 if ((sevent->attributes & ISC_SOCKEVENTATTR_PKTINFO) != 0) {
1231                         client->attributes |= NS_CLIENTATTR_PKTINFO;
1232                         client->pktinfo = sevent->pktinfo;
1233                 }
1234                 if ((sevent->attributes & ISC_SOCKEVENTATTR_MULTICAST) != 0)
1235                         client->attributes |= NS_CLIENTATTR_MULTICAST;
1236                 client->nrecvs--;
1237         } else {
1238                 INSIST(TCP_CLIENT(client));
1239                 REQUIRE(event->ev_type == DNS_EVENT_TCPMSG);
1240                 REQUIRE(event->ev_sender == &client->tcpmsg);
1241                 buffer = &client->tcpmsg.buffer;
1242                 result = client->tcpmsg.result;
1243                 INSIST(client->nreads == 1);
1244                 /*
1245                  * client->peeraddr was set when the connection was accepted.
1246                  */
1247                 client->nreads--;
1248         }
1249
1250         if (exit_check(client))
1251                 goto cleanup;
1252         client->state = client->newstate = NS_CLIENTSTATE_WORKING;
1253
1254         isc_task_getcurrenttime(task, &client->requesttime);
1255         client->now = client->requesttime;
1256
1257         if (result != ISC_R_SUCCESS) {
1258                 if (TCP_CLIENT(client)) {
1259                         ns_client_next(client, result);
1260                 } else {
1261                         if  (result != ISC_R_CANCELED)
1262                                 isc_log_write(ns_g_lctx, NS_LOGCATEGORY_CLIENT,
1263                                               NS_LOGMODULE_CLIENT,
1264                                               ISC_LOG_ERROR,
1265                                               "UDP client handler shutting "
1266                                               "down due to fatal receive "
1267                                               "error: %s",
1268                                               isc_result_totext(result));
1269                         isc_task_shutdown(client->task);
1270                 }
1271                 goto cleanup;
1272         }
1273
1274         isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
1275
1276 #if NS_CLIENT_DROPPORT
1277         if (ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) ==
1278             DROPPORT_REQUEST) {
1279                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1280                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
1281                               "dropped request: suspicious port");
1282                 ns_client_next(client, ISC_R_SUCCESS);
1283                 goto cleanup;
1284         }
1285 #endif
1286
1287         ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1288                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1289                       "%s request",
1290                       TCP_CLIENT(client) ? "TCP" : "UDP");
1291
1292         /*
1293          * Check the blackhole ACL for UDP only, since TCP is done in
1294          * client_newconn.
1295          */
1296         if (!TCP_CLIENT(client)) {
1297
1298                 if (ns_g_server->blackholeacl != NULL &&
1299                     dns_acl_match(&netaddr, NULL, ns_g_server->blackholeacl,
1300                                   &ns_g_server->aclenv,
1301                                   &match, NULL) == ISC_R_SUCCESS &&
1302                     match > 0)
1303                 {
1304                         ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1305                                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
1306                                       "blackholed UDP datagram");
1307                         ns_client_next(client, ISC_R_SUCCESS);
1308                         goto cleanup;
1309                 }
1310         }
1311
1312         /*
1313          * Silently drop multicast requests for the present.
1314          * XXXMPA look at when/if mDNS spec stabilizes.
1315          */
1316         if ((client->attributes & NS_CLIENTATTR_MULTICAST) != 0) {
1317                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1318                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
1319                               "dropping multicast request");
1320                 ns_client_next(client, DNS_R_REFUSED);
1321                 goto cleanup;
1322         }
1323
1324         result = dns_message_peekheader(buffer, &id, &flags);
1325         if (result != ISC_R_SUCCESS) {
1326                 /*
1327                  * There isn't enough header to determine whether
1328                  * this was a request or a response.  Drop it.
1329                  */
1330                 ns_client_next(client, result);
1331                 goto cleanup;
1332         }
1333
1334         /*
1335          * The client object handles requests, not responses.
1336          * If this is a UDP response, forward it to the dispatcher.
1337          * If it's a TCP response, discard it here.
1338          */
1339         if ((flags & DNS_MESSAGEFLAG_QR) != 0) {
1340                 if (TCP_CLIENT(client)) {
1341                         CTRACE("unexpected response");
1342                         ns_client_next(client, DNS_R_FORMERR);
1343                         goto cleanup;
1344                 } else {
1345                         dns_dispatch_importrecv(client->dispatch, event);
1346                         ns_client_next(client, ISC_R_SUCCESS);
1347                         goto cleanup;
1348                 }
1349         }
1350
1351         /*
1352          * It's a request.  Parse it.
1353          */
1354         result = dns_message_parse(client->message, buffer, 0);
1355         if (result != ISC_R_SUCCESS) {
1356                 /*
1357                  * Parsing the request failed.  Send a response
1358                  * (typically FORMERR or SERVFAIL).
1359                  */
1360                 ns_client_error(client, result);
1361                 goto cleanup;
1362         }
1363
1364         switch (client->message->opcode) {
1365         case dns_opcode_query:
1366         case dns_opcode_update:
1367         case dns_opcode_notify:
1368                 notimp = ISC_FALSE;
1369                 break;
1370         case dns_opcode_iquery:
1371         default:
1372                 notimp = ISC_TRUE;
1373                 break;
1374         }
1375
1376         client->message->rcode = dns_rcode_noerror;
1377
1378         /* RFC1123 section 6.1.3.2 */
1379         if ((client->attributes & NS_CLIENTATTR_MULTICAST) != 0)
1380                 client->message->flags &= ~DNS_MESSAGEFLAG_RD;
1381
1382         /*
1383          * Deal with EDNS.
1384          */
1385         opt = dns_message_getopt(client->message);
1386         if (opt != NULL) {
1387                 unsigned int version;
1388
1389                 /*
1390                  * Set the client's UDP buffer size.
1391                  */
1392                 client->udpsize = opt->rdclass;
1393
1394                 /*
1395                  * If the requested UDP buffer size is less than 512,
1396                  * ignore it and use 512.
1397                  */
1398                 if (client->udpsize < 512)
1399                         client->udpsize = 512;
1400
1401                 /*
1402                  * Get the flags out of the OPT record.
1403                  */
1404                 client->extflags = (isc_uint16_t)(opt->ttl & 0xFFFF);
1405
1406                 /*
1407                  * Create an OPT for our reply.
1408                  */
1409                 result = client_addopt(client);
1410                 if (result != ISC_R_SUCCESS) {
1411                         ns_client_error(client, result);
1412                         goto cleanup;
1413                 }
1414
1415                 /*
1416                  * Do we understand this version of ENDS?
1417                  *
1418                  * XXXRTH need library support for this!
1419                  */
1420                 version = (opt->ttl & 0x00FF0000) >> 16;
1421                 if (version != 0) {
1422                         ns_client_error(client, DNS_R_BADVERS);
1423                         goto cleanup;
1424                 }
1425         }
1426
1427         if (client->message->rdclass == 0) {
1428                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1429                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
1430                               "message class could not be determined");
1431                 ns_client_dumpmessage(client,
1432                                       "message class could not be determined");
1433                 ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_FORMERR);
1434                 goto cleanup;
1435         }
1436
1437         /*
1438          * Determine the destination address.  If the receiving interface is
1439          * bound to a specific address, we simply use it regardless of the
1440          * address family.  All IPv4 queries should fall into this case.
1441          * Otherwise, if this is a TCP query, get the address from the
1442          * receiving socket (this needs a system call and can be heavy).
1443          * For IPv6 UDP queries, we get this from the pktinfo structure (if
1444          * supported).
1445          * If all the attempts fail (this can happen due to memory shortage,
1446          * etc), we regard this as an error for safety.
1447          */
1448         if ((client->interface->flags & NS_INTERFACEFLAG_ANYADDR) == 0)
1449                 isc_netaddr_fromsockaddr(&destaddr, &client->interface->addr);
1450         else {
1451                 result = ISC_R_FAILURE;
1452
1453                 if (TCP_CLIENT(client)) {
1454                         isc_sockaddr_t destsockaddr;
1455
1456                         result = isc_socket_getsockname(client->tcpsocket,
1457                                                         &destsockaddr);
1458                         if (result == ISC_R_SUCCESS)
1459                                 isc_netaddr_fromsockaddr(&destaddr,
1460                                                          &destsockaddr);
1461                 }
1462                 if (result != ISC_R_SUCCESS &&
1463                     client->interface->addr.type.sa.sa_family == AF_INET6 &&
1464                     (client->attributes & NS_CLIENTATTR_PKTINFO) != 0) {
1465                         isc_uint32_t zone = 0;
1466
1467                         /*
1468                          * XXXJT technically, we should convert the receiving
1469                          * interface ID to a proper scope zone ID.  However,
1470                          * due to the fact there is no standard API for this,
1471                          * we only handle link-local addresses and use the
1472                          * interface index as link ID.  Despite the assumption,
1473                          * it should cover most typical cases.
1474                          */
1475                         if (IN6_IS_ADDR_LINKLOCAL(&client->pktinfo.ipi6_addr))
1476                                 zone = (isc_uint32_t)client->pktinfo.ipi6_ifindex;
1477
1478                         isc_netaddr_fromin6(&destaddr,
1479                                             &client->pktinfo.ipi6_addr);
1480                         isc_netaddr_setzone(&destaddr, zone);
1481                         result = ISC_R_SUCCESS;
1482                 }
1483                 if (result != ISC_R_SUCCESS) {
1484                         UNEXPECTED_ERROR(__FILE__, __LINE__,
1485                                          "failed to get request's "
1486                                          "destination: %s",
1487                                          isc_result_totext(result));
1488                         goto cleanup;
1489                 }
1490         }
1491
1492         /*
1493          * Find a view that matches the client's source address.
1494          */
1495         for (view = ISC_LIST_HEAD(ns_g_server->viewlist);
1496              view != NULL;
1497              view = ISC_LIST_NEXT(view, link)) {
1498                 if (client->message->rdclass == view->rdclass ||
1499                     client->message->rdclass == dns_rdataclass_any)
1500                 {
1501                         dns_name_t *tsig = NULL;
1502                         sigresult = dns_message_rechecksig(client->message,
1503                                                            view);
1504                         if (sigresult == ISC_R_SUCCESS)
1505                                 tsig = client->message->tsigname;
1506
1507                         if (allowed(&netaddr, tsig, view->matchclients) &&
1508                             allowed(&destaddr, tsig, view->matchdestinations) &&
1509                             !((client->message->flags & DNS_MESSAGEFLAG_RD)
1510                               == 0 && view->matchrecursiveonly))
1511                         {
1512                                 dns_view_attach(view, &client->view);
1513                                 break;
1514                         }
1515                 }
1516         }
1517
1518         if (view == NULL) {
1519                 char classname[DNS_RDATACLASS_FORMATSIZE];
1520
1521                 /*
1522                  * Do a dummy TSIG verification attempt so that the
1523                  * response will have a TSIG if the query did, as
1524                  * required by RFC2845.
1525                  */
1526                 isc_buffer_t b;
1527                 isc_region_t *r;
1528
1529                 dns_message_resetsig(client->message);
1530
1531                 r = dns_message_getrawmessage(client->message);
1532                 isc_buffer_init(&b, r->base, r->length);
1533                 isc_buffer_add(&b, r->length);
1534                 (void)dns_tsig_verify(&b, client->message, NULL, NULL);
1535
1536                 dns_rdataclass_format(client->message->rdclass, classname,
1537                                       sizeof(classname));
1538                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1539                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
1540                               "no matching view in class '%s'", classname);
1541                 ns_client_dumpmessage(client, "no matching view in class");
1542                 ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_REFUSED);
1543                 goto cleanup;
1544         }
1545
1546         ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1547                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(5),
1548                       "using view '%s'", view->name);
1549
1550         /*
1551          * Check for a signature.  We log bad signatures regardless of
1552          * whether they ultimately cause the request to be rejected or
1553          * not.  We do not log the lack of a signature unless we are
1554          * debugging.
1555          */
1556         client->signer = NULL;
1557         dns_name_init(&client->signername, NULL);
1558         result = dns_message_signer(client->message, &client->signername);
1559         if (result == ISC_R_SUCCESS) {
1560                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1561                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1562                               "request has valid signature");
1563                 client->signer = &client->signername;
1564         } else if (result == ISC_R_NOTFOUND) {
1565                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1566                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1567                               "request is not signed");
1568         } else if (result == DNS_R_NOIDENTITY) {
1569                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1570                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1571                               "request is signed by a nonauthoritative key");
1572         } else {
1573                 char tsigrcode[64];
1574                 isc_buffer_t b;
1575                 dns_name_t *name = NULL;
1576
1577                 isc_buffer_init(&b, tsigrcode, sizeof(tsigrcode) - 1);
1578                 RUNTIME_CHECK(dns_tsigrcode_totext(client->message->tsigstatus,
1579                                                    &b) == ISC_R_SUCCESS);
1580                 tsigrcode[isc_buffer_usedlength(&b)] = '\0';
1581                 /* There is a signature, but it is bad. */
1582                 if (dns_message_gettsig(client->message, &name) != NULL) {
1583                         char namebuf[DNS_NAME_FORMATSIZE];
1584                         dns_name_format(name, namebuf, sizeof(namebuf));
1585                         ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1586                                       NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
1587                                       "request has invalid signature: "
1588                                       "TSIG %s: %s (%s)", namebuf,
1589                                       isc_result_totext(result), tsigrcode);
1590                 } else {
1591                         ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1592                                       NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
1593                                       "request has invalid signature: %s (%s)",
1594                                       isc_result_totext(result), tsigrcode);
1595                 }
1596                 /*
1597                  * Accept update messages signed by unknown keys so that
1598                  * update forwarding works transparently through slaves
1599                  * that don't have all the same keys as the master.
1600                  */
1601                 if (!(client->message->tsigstatus == dns_tsigerror_badkey &&
1602                       client->message->opcode == dns_opcode_update)) {
1603                         ns_client_error(client, sigresult);
1604                         goto cleanup;
1605                 }
1606         }
1607
1608         /*
1609          * Decide whether recursive service is available to this client.
1610          * We do this here rather than in the query code so that we can
1611          * set the RA bit correctly on all kinds of responses, not just
1612          * responses to ordinary queries.  Note if you can't query the
1613          * cache there is no point in setting RA.
1614          */
1615         ra = ISC_FALSE;
1616         if (client->view->resolver != NULL &&
1617             client->view->recursion == ISC_TRUE &&
1618             ns_client_checkaclsilent(client, client->view->recursionacl,
1619                                      ISC_TRUE) == ISC_R_SUCCESS &&
1620             ns_client_checkaclsilent(client, client->view->queryacl,
1621                                      ISC_TRUE) == ISC_R_SUCCESS)
1622                 ra = ISC_TRUE;
1623
1624         if (ra == ISC_TRUE)
1625                 client->attributes |= NS_CLIENTATTR_RA;
1626
1627         ns_client_log(client, DNS_LOGCATEGORY_SECURITY, NS_LOGMODULE_CLIENT,
1628                       ISC_LOG_DEBUG(3), ra ? "recursion available" :
1629                                              "recursion not available");
1630
1631         /*
1632          * Dispatch the request.
1633          */
1634         switch (client->message->opcode) {
1635         case dns_opcode_query:
1636                 CTRACE("query");
1637                 ns_query_start(client);
1638                 break;
1639         case dns_opcode_update:
1640                 CTRACE("update");
1641                 ns_client_settimeout(client, 60);
1642                 ns_update_start(client, sigresult);
1643                 break;
1644         case dns_opcode_notify:
1645                 CTRACE("notify");
1646                 ns_client_settimeout(client, 60);
1647                 ns_notify_start(client);
1648                 break;
1649         case dns_opcode_iquery:
1650                 CTRACE("iquery");
1651                 ns_client_error(client, DNS_R_NOTIMP);
1652                 break;
1653         default:
1654                 CTRACE("unknown opcode");
1655                 ns_client_error(client, DNS_R_NOTIMP);
1656         }
1657
1658  cleanup:
1659         return;
1660 }
1661
1662 static void
1663 client_timeout(isc_task_t *task, isc_event_t *event) {
1664         ns_client_t *client;
1665
1666         REQUIRE(event != NULL);
1667         REQUIRE(event->ev_type == ISC_TIMEREVENT_LIFE ||
1668                 event->ev_type == ISC_TIMEREVENT_IDLE);
1669         client = event->ev_arg;
1670         REQUIRE(NS_CLIENT_VALID(client));
1671         REQUIRE(task == client->task);
1672         REQUIRE(client->timer != NULL);
1673
1674         UNUSED(task);
1675
1676         CTRACE("timeout");
1677
1678         isc_event_free(&event);
1679
1680         if (client->shutdown != NULL) {
1681                 (client->shutdown)(client->shutdown_arg, ISC_R_TIMEDOUT);
1682                 client->shutdown = NULL;
1683                 client->shutdown_arg = NULL;
1684         }
1685
1686         if (client->newstate > NS_CLIENTSTATE_READY)
1687                 client->newstate = NS_CLIENTSTATE_READY;
1688         (void)exit_check(client);
1689 }
1690
1691 static isc_result_t
1692 client_create(ns_clientmgr_t *manager, ns_client_t **clientp) {
1693         ns_client_t *client;
1694         isc_result_t result;
1695
1696         /*
1697          * Caller must be holding the manager lock.
1698          *
1699          * Note: creating a client does not add the client to the
1700          * manager's client list or set the client's manager pointer.
1701          * The caller is responsible for that.
1702          */
1703
1704         REQUIRE(clientp != NULL && *clientp == NULL);
1705
1706         client = isc_mem_get(manager->mctx, sizeof(*client));
1707         if (client == NULL)
1708                 return (ISC_R_NOMEMORY);
1709
1710         client->task = NULL;
1711         result = isc_task_create(manager->taskmgr, 0, &client->task);
1712         if (result != ISC_R_SUCCESS)
1713                 goto cleanup_client;
1714         isc_task_setname(client->task, "client", client);
1715
1716         client->timer = NULL;
1717         result = isc_timer_create(manager->timermgr, isc_timertype_inactive,
1718                                   NULL, NULL, client->task, client_timeout,
1719                                   client, &client->timer);
1720         if (result != ISC_R_SUCCESS)
1721                 goto cleanup_task;
1722         client->timerset = ISC_FALSE;
1723
1724         client->message = NULL;
1725         result = dns_message_create(manager->mctx, DNS_MESSAGE_INTENTPARSE,
1726                                     &client->message);
1727         if (result != ISC_R_SUCCESS)
1728                 goto cleanup_timer;
1729
1730         /* XXXRTH  Hardwired constants */
1731
1732         client->sendevent = (isc_socketevent_t *)
1733                             isc_event_allocate(manager->mctx, client,
1734                                                ISC_SOCKEVENT_SENDDONE,
1735                                                client_senddone, client,
1736                                                sizeof(isc_socketevent_t));
1737         if (client->sendevent == NULL) {
1738                 result = ISC_R_NOMEMORY;
1739                 goto cleanup_message;
1740         }
1741
1742         client->recvbuf = isc_mem_get(manager->mctx, RECV_BUFFER_SIZE);
1743         if  (client->recvbuf == NULL) {
1744                 result = ISC_R_NOMEMORY;
1745                 goto cleanup_sendevent;
1746         }
1747
1748         client->recvevent = (isc_socketevent_t *)
1749                             isc_event_allocate(manager->mctx, client,
1750                                                ISC_SOCKEVENT_RECVDONE,
1751                                                client_request, client,
1752                                                sizeof(isc_socketevent_t));
1753         if (client->recvevent == NULL) {
1754                 result = ISC_R_NOMEMORY;
1755                 goto cleanup_recvbuf;
1756         }
1757
1758         client->magic = NS_CLIENT_MAGIC;
1759         client->mctx = manager->mctx;
1760         client->manager = NULL;
1761         client->state = NS_CLIENTSTATE_INACTIVE;
1762         client->newstate = NS_CLIENTSTATE_MAX;
1763         client->naccepts = 0;
1764         client->nreads = 0;
1765         client->nsends = 0;
1766         client->nrecvs = 0;
1767         client->nupdates = 0;
1768         client->nctls = 0;
1769         client->references = 0;
1770         client->attributes = 0;
1771         client->view = NULL;
1772         client->dispatch = NULL;
1773         client->udpsocket = NULL;
1774         client->tcplistener = NULL;
1775         client->tcpsocket = NULL;
1776         client->tcpmsg_valid = ISC_FALSE;
1777         client->tcpbuf = NULL;
1778         client->opt = NULL;
1779         client->udpsize = 512;
1780         client->extflags = 0;
1781         client->next = NULL;
1782         client->shutdown = NULL;
1783         client->shutdown_arg = NULL;
1784         dns_name_init(&client->signername, NULL);
1785         client->mortal = ISC_FALSE;
1786         client->tcpquota = NULL;
1787         client->recursionquota = NULL;
1788         client->interface = NULL;
1789         client->peeraddr_valid = ISC_FALSE;
1790         ISC_EVENT_INIT(&client->ctlevent, sizeof(client->ctlevent), 0, NULL,
1791                        NS_EVENT_CLIENTCONTROL, client_start, client, client,
1792                        NULL, NULL);
1793         /*
1794          * Initialize FORMERR cache to sentinel value that will not match
1795          * any actual FORMERR response.
1796          */
1797         isc_sockaddr_any(&client->formerrcache.addr);
1798         client->formerrcache.time = 0;
1799         client->formerrcache.id = 0;
1800         ISC_LINK_INIT(client, link);
1801         client->list = NULL;
1802
1803         /*
1804          * We call the init routines for the various kinds of client here,
1805          * after we have created an otherwise valid client, because some
1806          * of them call routines that REQUIRE(NS_CLIENT_VALID(client)).
1807          */
1808         result = ns_query_init(client);
1809         if (result != ISC_R_SUCCESS)
1810                 goto cleanup_recvevent;
1811
1812         result = isc_task_onshutdown(client->task, client_shutdown, client);
1813         if (result != ISC_R_SUCCESS)
1814                 goto cleanup_query;
1815
1816         CTRACE("create");
1817
1818         *clientp = client;
1819
1820         return (ISC_R_SUCCESS);
1821
1822  cleanup_query:
1823         ns_query_free(client);
1824
1825  cleanup_recvevent:
1826         isc_event_free((isc_event_t **)&client->recvevent);
1827
1828  cleanup_recvbuf:
1829         isc_mem_put(manager->mctx, client->recvbuf, RECV_BUFFER_SIZE);
1830
1831  cleanup_sendevent:
1832         isc_event_free((isc_event_t **)&client->sendevent);
1833
1834         client->magic = 0;
1835
1836  cleanup_message:
1837         dns_message_destroy(&client->message);
1838
1839  cleanup_timer:
1840         isc_timer_detach(&client->timer);
1841
1842  cleanup_task:
1843         isc_task_detach(&client->task);
1844
1845  cleanup_client:
1846         isc_mem_put(manager->mctx, client, sizeof(*client));
1847
1848         return (result);
1849 }
1850
1851 static void
1852 client_read(ns_client_t *client) {
1853         isc_result_t result;
1854
1855         CTRACE("read");
1856
1857         result = dns_tcpmsg_readmessage(&client->tcpmsg, client->task,
1858                                         client_request, client);
1859         if (result != ISC_R_SUCCESS)
1860                 goto fail;
1861
1862         /*
1863          * Set a timeout to limit the amount of time we will wait
1864          * for a request on this TCP connection.
1865          */
1866         ns_client_settimeout(client, 30);
1867
1868         client->state = client->newstate = NS_CLIENTSTATE_READING;
1869         INSIST(client->nreads == 0);
1870         INSIST(client->recursionquota == NULL);
1871         client->nreads++;
1872
1873         return;
1874  fail:
1875         ns_client_next(client, result);
1876 }
1877
1878 static void
1879 client_newconn(isc_task_t *task, isc_event_t *event) {
1880         ns_client_t *client = event->ev_arg;
1881         isc_socket_newconnev_t *nevent = (isc_socket_newconnev_t *)event;
1882         isc_result_t result;
1883
1884         REQUIRE(event->ev_type == ISC_SOCKEVENT_NEWCONN);
1885         REQUIRE(NS_CLIENT_VALID(client));
1886         REQUIRE(client->task == task);
1887
1888         UNUSED(task);
1889
1890         INSIST(client->state == NS_CLIENTSTATE_READY);
1891
1892         INSIST(client->naccepts == 1);
1893         client->naccepts--;
1894
1895         LOCK(&client->interface->lock);
1896         INSIST(client->interface->ntcpcurrent > 0);
1897         client->interface->ntcpcurrent--;
1898         UNLOCK(&client->interface->lock);
1899
1900         /*
1901          * We must take ownership of the new socket before the exit
1902          * check to make sure it gets destroyed if we decide to exit.
1903          */
1904         if (nevent->result == ISC_R_SUCCESS) {
1905                 client->tcpsocket = nevent->newsocket;
1906                 client->state = NS_CLIENTSTATE_READING;
1907                 INSIST(client->recursionquota == NULL);
1908
1909                 (void)isc_socket_getpeername(client->tcpsocket,
1910                                              &client->peeraddr);
1911                 client->peeraddr_valid = ISC_TRUE;
1912                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1913                            NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1914                            "new TCP connection");
1915         } else {
1916                 /*
1917                  * XXXRTH  What should we do?  We're trying to accept but
1918                  *         it didn't work.  If we just give up, then TCP
1919                  *         service may eventually stop.
1920                  *
1921                  *         For now, we just go idle.
1922                  *
1923                  *         Going idle is probably the right thing if the
1924                  *         I/O was canceled.
1925                  */
1926                 ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1927                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
1928                               "accept failed: %s",
1929                               isc_result_totext(nevent->result));
1930         }
1931
1932         if (exit_check(client))
1933                 goto freeevent;
1934
1935         if (nevent->result == ISC_R_SUCCESS) {
1936                 int match;
1937                 isc_netaddr_t netaddr;
1938
1939                 isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
1940
1941                 if (ns_g_server->blackholeacl != NULL &&
1942                     dns_acl_match(&netaddr, NULL,
1943                                   ns_g_server->blackholeacl,
1944                                   &ns_g_server->aclenv,
1945                                   &match, NULL) == ISC_R_SUCCESS &&
1946                     match > 0)
1947                 {
1948                         ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
1949                                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
1950                                       "blackholed connection attempt");
1951                         client->newstate = NS_CLIENTSTATE_READY;
1952                         (void)exit_check(client);
1953                         goto freeevent;
1954                 }
1955
1956                 INSIST(client->tcpmsg_valid == ISC_FALSE);
1957                 dns_tcpmsg_init(client->mctx, client->tcpsocket,
1958                                 &client->tcpmsg);
1959                 client->tcpmsg_valid = ISC_TRUE;
1960
1961                 /*
1962                  * Let a new client take our place immediately, before
1963                  * we wait for a request packet.  If we don't,
1964                  * telnetting to port 53 (once per CPU) will
1965                  * deny service to legititmate TCP clients.
1966                  */
1967                 result = isc_quota_attach(&ns_g_server->tcpquota,
1968                                           &client->tcpquota);
1969                 if (result == ISC_R_SUCCESS)
1970                         result = ns_client_replace(client);
1971                 if (result != ISC_R_SUCCESS) {
1972                         ns_client_log(client, NS_LOGCATEGORY_CLIENT,
1973                                       NS_LOGMODULE_CLIENT, ISC_LOG_WARNING,
1974                                       "no more TCP clients: %s",
1975                                       isc_result_totext(result));
1976                 }
1977
1978                 client_read(client);
1979         }
1980
1981  freeevent:
1982         isc_event_free(&event);
1983 }
1984
1985 static void
1986 client_accept(ns_client_t *client) {
1987         isc_result_t result;
1988
1989         CTRACE("accept");
1990
1991         result = isc_socket_accept(client->tcplistener, client->task,
1992                                    client_newconn, client);
1993         if (result != ISC_R_SUCCESS) {
1994                 UNEXPECTED_ERROR(__FILE__, __LINE__,
1995                                  "isc_socket_accept() failed: %s",
1996                                  isc_result_totext(result));
1997                 /*
1998                  * XXXRTH  What should we do?  We're trying to accept but
1999                  *         it didn't work.  If we just give up, then TCP
2000                  *         service may eventually stop.
2001                  *
2002                  *         For now, we just go idle.
2003                  */
2004                 return;
2005         }
2006         INSIST(client->naccepts == 0);
2007         client->naccepts++;
2008         LOCK(&client->interface->lock);
2009         client->interface->ntcpcurrent++;
2010         UNLOCK(&client->interface->lock);
2011 }
2012
2013 static void
2014 client_udprecv(ns_client_t *client) {
2015         isc_result_t result;
2016         isc_region_t r;
2017
2018         CTRACE("udprecv");
2019
2020         r.base = client->recvbuf;
2021         r.length = RECV_BUFFER_SIZE;
2022         result = isc_socket_recv2(client->udpsocket, &r, 1,
2023                                   client->task, client->recvevent, 0);
2024         if (result != ISC_R_SUCCESS) {
2025                 UNEXPECTED_ERROR(__FILE__, __LINE__,
2026                                  "isc_socket_recv2() failed: %s",
2027                                  isc_result_totext(result));
2028                 /*
2029                  * This cannot happen in the current implementation, since
2030                  * isc_socket_recv2() cannot fail if flags == 0.
2031                  *
2032                  * If this does fail, we just go idle.
2033                  */
2034                 return;
2035         }
2036         INSIST(client->nrecvs == 0);
2037         client->nrecvs++;
2038 }
2039
2040 void
2041 ns_client_attach(ns_client_t *source, ns_client_t **targetp) {
2042         REQUIRE(NS_CLIENT_VALID(source));
2043         REQUIRE(targetp != NULL && *targetp == NULL);
2044
2045         source->references++;
2046         ns_client_log(source, NS_LOGCATEGORY_CLIENT,
2047                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
2048                       "ns_client_attach: ref = %d", source->references);
2049         *targetp = source;
2050 }
2051
2052 void
2053 ns_client_detach(ns_client_t **clientp) {
2054         ns_client_t *client = *clientp;
2055
2056         client->references--;
2057         INSIST(client->references >= 0);
2058         *clientp = NULL;
2059         ns_client_log(client, NS_LOGCATEGORY_CLIENT,
2060                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
2061                       "ns_client_detach: ref = %d", client->references);
2062         (void)exit_check(client);
2063 }
2064
2065 isc_boolean_t
2066 ns_client_shuttingdown(ns_client_t *client) {
2067         return (ISC_TF(client->newstate == NS_CLIENTSTATE_FREED));
2068 }
2069
2070 isc_result_t
2071 ns_client_replace(ns_client_t *client) {
2072         isc_result_t result;
2073
2074         CTRACE("replace");
2075
2076         result = ns_clientmgr_createclients(client->manager,
2077                                             1, client->interface,
2078                                             (TCP_CLIENT(client) ?
2079                                              ISC_TRUE : ISC_FALSE));
2080         if (result != ISC_R_SUCCESS)
2081                 return (result);
2082
2083         /*
2084          * The responsibility for listening for new requests is hereby
2085          * transferred to the new client.  Therefore, the old client
2086          * should refrain from listening for any more requests.
2087          */
2088         client->mortal = ISC_TRUE;
2089
2090         return (ISC_R_SUCCESS);
2091 }
2092
2093 /***
2094  *** Client Manager
2095  ***/
2096
2097 static void
2098 clientmgr_destroy(ns_clientmgr_t *manager) {
2099         REQUIRE(ISC_LIST_EMPTY(manager->active));
2100         REQUIRE(ISC_LIST_EMPTY(manager->inactive));
2101         REQUIRE(ISC_LIST_EMPTY(manager->recursing));
2102
2103         MTRACE("clientmgr_destroy");
2104
2105         DESTROYLOCK(&manager->lock);
2106         manager->magic = 0;
2107         isc_mem_put(manager->mctx, manager, sizeof(*manager));
2108 }
2109
2110 isc_result_t
2111 ns_clientmgr_create(isc_mem_t *mctx, isc_taskmgr_t *taskmgr,
2112                     isc_timermgr_t *timermgr, ns_clientmgr_t **managerp)
2113 {
2114         ns_clientmgr_t *manager;
2115         isc_result_t result;
2116
2117         manager = isc_mem_get(mctx, sizeof(*manager));
2118         if (manager == NULL)
2119                 return (ISC_R_NOMEMORY);
2120
2121         result = isc_mutex_init(&manager->lock);
2122         if (result != ISC_R_SUCCESS)
2123                 goto cleanup_manager;
2124
2125         manager->mctx = mctx;
2126         manager->taskmgr = taskmgr;
2127         manager->timermgr = timermgr;
2128         manager->exiting = ISC_FALSE;
2129         ISC_LIST_INIT(manager->active);
2130         ISC_LIST_INIT(manager->inactive);
2131         ISC_LIST_INIT(manager->recursing);
2132         manager->magic = MANAGER_MAGIC;
2133
2134         MTRACE("create");
2135
2136         *managerp = manager;
2137
2138         return (ISC_R_SUCCESS);
2139
2140  cleanup_manager:
2141         isc_mem_put(manager->mctx, manager, sizeof(*manager));
2142
2143         return (result);
2144 }
2145
2146 void
2147 ns_clientmgr_destroy(ns_clientmgr_t **managerp) {
2148         ns_clientmgr_t *manager;
2149         ns_client_t *client;
2150         isc_boolean_t need_destroy = ISC_FALSE;
2151
2152         REQUIRE(managerp != NULL);
2153         manager = *managerp;
2154         REQUIRE(VALID_MANAGER(manager));
2155
2156         MTRACE("destroy");
2157
2158         LOCK(&manager->lock);
2159
2160         manager->exiting = ISC_TRUE;
2161
2162         for (client = ISC_LIST_HEAD(manager->recursing);
2163              client != NULL;
2164              client = ISC_LIST_NEXT(client, link))
2165                 isc_task_shutdown(client->task);
2166
2167         for (client = ISC_LIST_HEAD(manager->active);
2168              client != NULL;
2169              client = ISC_LIST_NEXT(client, link))
2170                 isc_task_shutdown(client->task);
2171
2172         for (client = ISC_LIST_HEAD(manager->inactive);
2173              client != NULL;
2174              client = ISC_LIST_NEXT(client, link))
2175                 isc_task_shutdown(client->task);
2176
2177         if (ISC_LIST_EMPTY(manager->active) &&
2178             ISC_LIST_EMPTY(manager->inactive) &&
2179             ISC_LIST_EMPTY(manager->recursing))
2180                 need_destroy = ISC_TRUE;
2181
2182         UNLOCK(&manager->lock);
2183
2184         if (need_destroy)
2185                 clientmgr_destroy(manager);
2186
2187         *managerp = NULL;
2188 }
2189
2190 isc_result_t
2191 ns_clientmgr_createclients(ns_clientmgr_t *manager, unsigned int n,
2192                            ns_interface_t *ifp, isc_boolean_t tcp)
2193 {
2194         isc_result_t result = ISC_R_SUCCESS;
2195         unsigned int i;
2196         ns_client_t *client;
2197
2198         REQUIRE(VALID_MANAGER(manager));
2199         REQUIRE(n > 0);
2200
2201         MTRACE("createclients");
2202
2203         /*
2204          * We MUST lock the manager lock for the entire client creation
2205          * process.  If we didn't do this, then a client could get a
2206          * shutdown event and disappear out from under us.
2207          */
2208
2209         LOCK(&manager->lock);
2210
2211         for (i = 0; i < n; i++) {
2212                 isc_event_t *ev;
2213                 /*
2214                  * Allocate a client.  First try to get a recycled one;
2215                  * if that fails, make a new one.
2216                  */
2217                 client = ISC_LIST_HEAD(manager->inactive);
2218                 if (client != NULL) {
2219                         MTRACE("recycle");
2220                         ISC_LIST_UNLINK(manager->inactive, client, link);
2221                         client->list = NULL;
2222                 } else {
2223                         MTRACE("create new");
2224                         result = client_create(manager, &client);
2225                         if (result != ISC_R_SUCCESS)
2226                                 break;
2227                 }
2228
2229                 ns_interface_attach(ifp, &client->interface);
2230                 client->state = NS_CLIENTSTATE_READY;
2231                 INSIST(client->recursionquota == NULL);
2232
2233                 if (tcp) {
2234                         client->attributes |= NS_CLIENTATTR_TCP;
2235                         isc_socket_attach(ifp->tcpsocket,
2236                                           &client->tcplistener);
2237                 } else {
2238                         isc_socket_t *sock;
2239
2240                         dns_dispatch_attach(ifp->udpdispatch,
2241                                             &client->dispatch);
2242                         sock = dns_dispatch_getsocket(client->dispatch);
2243                         isc_socket_attach(sock, &client->udpsocket);
2244                 }
2245                 client->manager = manager;
2246                 ISC_LIST_APPEND(manager->active, client, link);
2247                 client->list = &manager->active;
2248
2249                 INSIST(client->nctls == 0);
2250                 client->nctls++;
2251                 ev = &client->ctlevent;
2252                 isc_task_send(client->task, &ev);
2253         }
2254         if (i != 0) {
2255                 /*
2256                  * We managed to create at least one client, so we
2257                  * declare victory.
2258                  */
2259                 result = ISC_R_SUCCESS;
2260         }
2261
2262         UNLOCK(&manager->lock);
2263
2264         return (result);
2265 }
2266
2267 isc_sockaddr_t *
2268 ns_client_getsockaddr(ns_client_t *client) {
2269         return (&client->peeraddr);
2270 }
2271
2272 isc_result_t
2273 ns_client_checkaclsilent(ns_client_t *client, dns_acl_t *acl,
2274                          isc_boolean_t default_allow)
2275 {
2276         isc_result_t result;
2277         int match;
2278         isc_netaddr_t netaddr;
2279
2280         if (acl == NULL) {
2281                 if (default_allow)
2282                         goto allow;
2283                 else
2284                         goto deny;
2285         }
2286
2287         isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
2288
2289         result = dns_acl_match(&netaddr, client->signer, acl,
2290                                &ns_g_server->aclenv,
2291                                &match, NULL);
2292         if (result != ISC_R_SUCCESS)
2293                 goto deny; /* Internal error, already logged. */
2294         if (match > 0)
2295                 goto allow;
2296         goto deny; /* Negative match or no match. */
2297
2298  allow:
2299         return (ISC_R_SUCCESS);
2300
2301  deny:
2302         return (DNS_R_REFUSED);
2303 }
2304
2305 isc_result_t
2306 ns_client_checkacl(ns_client_t *client,
2307                    const char *opname, dns_acl_t *acl,
2308                    isc_boolean_t default_allow, int log_level)
2309 {
2310         isc_result_t result =
2311                 ns_client_checkaclsilent(client, acl, default_allow);
2312
2313         if (result == ISC_R_SUCCESS)
2314                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
2315                               NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
2316                               "%s approved", opname);
2317         else
2318                 ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
2319                               NS_LOGMODULE_CLIENT,
2320                               log_level, "%s denied", opname);
2321         return (result);
2322 }
2323
2324 static void
2325 ns_client_name(ns_client_t *client, char *peerbuf, size_t len) {
2326         if (client->peeraddr_valid)
2327                 isc_sockaddr_format(&client->peeraddr, peerbuf, len);
2328         else
2329                 snprintf(peerbuf, len, "@%p", client);
2330 }
2331
2332 void
2333 ns_client_logv(ns_client_t *client, isc_logcategory_t *category,
2334            isc_logmodule_t *module, int level, const char *fmt, va_list ap)
2335 {
2336         char msgbuf[2048];
2337         char peerbuf[ISC_SOCKADDR_FORMATSIZE];
2338         const char *name = "";
2339         const char *sep = "";
2340
2341         vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
2342         ns_client_name(client, peerbuf, sizeof(peerbuf));
2343         if (client->view != NULL && strcmp(client->view->name, "_bind") != 0 &&
2344             strcmp(client->view->name, "_default") != 0) {
2345                 name = client->view->name;
2346                 sep = ": view ";
2347         }
2348
2349         isc_log_write(ns_g_lctx, category, module, level,
2350                       "client %s%s%s: %s", peerbuf, sep, name, msgbuf);
2351 }
2352
2353 void
2354 ns_client_log(ns_client_t *client, isc_logcategory_t *category,
2355            isc_logmodule_t *module, int level, const char *fmt, ...)
2356 {
2357         va_list ap;
2358
2359         if (! isc_log_wouldlog(ns_g_lctx, level))
2360                 return;
2361
2362         va_start(ap, fmt);
2363         ns_client_logv(client, category, module, level, fmt, ap);
2364         va_end(ap);
2365 }
2366
2367 void
2368 ns_client_aclmsg(const char *msg, dns_name_t *name, dns_rdatatype_t type,
2369                  dns_rdataclass_t rdclass, char *buf, size_t len)
2370 {
2371         char namebuf[DNS_NAME_FORMATSIZE];
2372         char typebuf[DNS_RDATATYPE_FORMATSIZE];
2373         char classbuf[DNS_RDATACLASS_FORMATSIZE];
2374
2375         dns_name_format(name, namebuf, sizeof(namebuf));
2376         dns_rdatatype_format(type, typebuf, sizeof(typebuf));
2377         dns_rdataclass_format(rdclass, classbuf, sizeof(classbuf));
2378         (void)snprintf(buf, len, "%s '%s/%s/%s'", msg, namebuf, typebuf,
2379                        classbuf);
2380 }
2381
2382 static void
2383 ns_client_dumpmessage(ns_client_t *client, const char *reason) {
2384         isc_buffer_t buffer;
2385         char *buf = NULL;
2386         int len = 1024;
2387         isc_result_t result;
2388
2389         /*
2390          * Note that these are multiline debug messages.  We want a newline
2391          * to appear in the log after each message.
2392          */
2393
2394         do {
2395                 buf = isc_mem_get(client->mctx, len);
2396                 if (buf == NULL)
2397                         break;
2398                 isc_buffer_init(&buffer, buf, len);
2399                 result = dns_message_totext(client->message,
2400                                             &dns_master_style_debug,
2401                                             0, &buffer);
2402                 if (result == ISC_R_NOSPACE) {
2403                         isc_mem_put(client->mctx, buf, len);
2404                         len += 1024;
2405                 } else if (result == ISC_R_SUCCESS)
2406                         ns_client_log(client, NS_LOGCATEGORY_UNMATCHED,
2407                                       NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
2408                                       "%s\n%.*s", reason,
2409                                        (int)isc_buffer_usedlength(&buffer),
2410                                        buf);
2411         } while (result == ISC_R_NOSPACE);
2412
2413         if (buf != NULL)
2414                 isc_mem_put(client->mctx, buf, len);
2415 }
2416
2417 void
2418 ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager) {
2419         ns_client_t *client;
2420         char namebuf[DNS_NAME_FORMATSIZE];
2421         char peerbuf[ISC_SOCKADDR_FORMATSIZE];
2422         const char *name;
2423         const char *sep;
2424
2425         REQUIRE(VALID_MANAGER(manager));
2426
2427         LOCK(&manager->lock);
2428         client = ISC_LIST_HEAD(manager->recursing);
2429         while (client != NULL) {
2430                 ns_client_name(client, peerbuf, sizeof(peerbuf));
2431                 if (client->view != NULL &&
2432                     strcmp(client->view->name, "_bind") != 0 &&
2433                     strcmp(client->view->name, "_default") != 0) {
2434                         name = client->view->name;
2435                         sep = ": view ";
2436                 } else {
2437                         name = "";
2438                         sep = "";
2439                 }
2440                 dns_name_format(client->query.qname, namebuf, sizeof(namebuf));
2441                 fprintf(f, "; client %s%s%s: '%s' requesttime %d\n",
2442                         peerbuf, sep, name, namebuf, client->requesttime);
2443                 client = ISC_LIST_NEXT(client, link);
2444         }
2445         UNLOCK(&manager->lock);
2446 }
2447
2448 void
2449 ns_client_qnamereplace(ns_client_t *client, dns_name_t *name) {
2450
2451         if (client->manager != NULL)
2452                 LOCK(&client->manager->lock);
2453         if (client->query.restarts > 0) {
2454                 /*
2455                  * client->query.qname was dynamically allocated.
2456                  */
2457                 dns_message_puttempname(client->message,
2458                                         &client->query.qname);
2459         }
2460         client->query.qname = name;
2461         if (client->manager != NULL)
2462                 UNLOCK(&client->manager->lock);
2463 }