1 /* $NetBSD: client.h,v 1.23 2026/09/17 18:01:18 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * SPDX-License-Identifier: MPL-2.0 7 * 8 * This Source Code Form is subject to the terms of the Mozilla Public 9 * License, v. 2.0. If a copy of the MPL was not distributed with this 10 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 11 * 12 * See the COPYRIGHT file distributed with this work for additional 13 * information regarding copyright ownership. 14 */ 15 16 #pragma once 17 18 /***** 19 ***** Module Info 20 *****/ 21 22 /*! \file 23 * \brief 24 * This module defines two objects, ns_client_t and ns_clientmgr_t. 25 * 26 * An ns_client_t object handles incoming DNS requests from clients 27 * on a given network interface. 28 * 29 * Each ns_client_t object can handle only one TCP connection or UDP 30 * request at a time. Therefore, several ns_client_t objects are 31 * typically created to serve each network interface, e.g., one 32 * for handling TCP requests and a few (one per CPU) for handling 33 * UDP requests. 34 * 35 * Incoming requests are classified as queries, zone transfer 36 * requests, update requests, notify requests, etc, and handed off 37 * to the appropriate request handler. When the request has been 38 * fully handled (which can be much later), the ns_client_t must be 39 * notified of this by calling one of the following functions 40 * exactly once in the context of its task: 41 * \code 42 * ns_client_send() (sending a non-error response) 43 * ns_client_sendraw() (sending a raw response) 44 * ns_client_error() (sending an error response) 45 * ns_client_drop() (sending no response, logging the reason) 46 *\endcode 47 * This will release any resources used by the request and 48 * and allow the ns_client_t to listen for the next request. 49 * 50 * A ns_clientmgr_t manages a number of ns_client_t objects. 51 * New ns_client_t objects are created by calling 52 * ns_clientmgr_createclients(). They are destroyed by 53 * destroying their manager. 54 */ 55 56 /*** 57 *** Imports 58 ***/ 59 60 #include <inttypes.h> 61 #include <stdbool.h> 62 63 #include <isc/atomic.h> 64 #include <isc/buffer.h> 65 #include <isc/magic.h> 66 #include <isc/netmgr.h> 67 #include <isc/quota.h> 68 #include <isc/stdtime.h> 69 70 #include <dns/db.h> 71 #include <dns/ecs.h> 72 #include <dns/fixedname.h> 73 #include <dns/name.h> 74 #include <dns/rdataclass.h> 75 #include <dns/rdatatype.h> 76 #include <dns/types.h> 77 78 #include <ns/query.h> 79 #include <ns/types.h> 80 81 /*** 82 *** Types 83 ***/ 84 85 #define NS_CLIENT_TCP_BUFFER_SIZE 65535 86 #define NS_CLIENT_SEND_BUFFER_SIZE 4096 87 88 /*! 89 * Client object states. Ordering is significant: higher-numbered 90 * states are generally "more active", meaning that the client can 91 * have more dynamically allocated data, outstanding events, etc. 92 * In the list below, any such properties listed for state N 93 * also apply to any state > N. 94 */ 95 96 typedef enum { 97 NS_CLIENTSTATE_FREED = 0, 98 /*%< 99 * The client object no longer exists. 100 */ 101 102 NS_CLIENTSTATE_INACTIVE = 1, 103 /*%< 104 * The client object exists and has a task and timer. 105 * Its "query" struct and sendbuf are initialized. 106 * It has a message and OPT, both in the reset state. 107 */ 108 109 NS_CLIENTSTATE_READY = 2, 110 /*%< 111 * The client object is either a TCP or a UDP one, and 112 * it is associated with a network interface. It is on the 113 * client manager's list of active clients. 114 * 115 * If it is a TCP client object, it has a TCP listener socket 116 * and an outstanding TCP listen request. 117 * 118 * If it is a UDP client object, it has a UDP listener socket 119 * and an outstanding UDP receive request. 120 */ 121 122 NS_CLIENTSTATE_WORKING = 3, 123 /*%< 124 * The client object has received a request and is working 125 * on it. It has a view, and it may have any of a non-reset OPT, 126 * recursion quota, and an outstanding write request. 127 */ 128 129 NS_CLIENTSTATE_RECURSING = 4, 130 /*%< 131 * The client object is recursing. It will be on the 132 * 'recursing' list. 133 */ 134 135 NS_CLIENTSTATE_MAX = 5 136 /*%< 137 * Sentinel value used to indicate "no state". 138 */ 139 } ns_clientstate_t; 140 141 typedef ISC_LIST(ns_client_t) client_list_t; 142 143 /*% nameserver client manager structure */ 144 struct ns_clientmgr { 145 /* Unlocked. */ 146 unsigned int magic; 147 148 isc_mem_t *mctx; 149 isc_mempool_t *namepool; 150 isc_mempool_t *rdspool; 151 152 ns_server_t *sctx; 153 isc_refcount_t references; 154 uint32_t tid; 155 isc_loop_t *loop; 156 157 dns_aclenv_t *aclenv; 158 159 /* Lock covers the recursing list */ 160 isc_mutex_t reclock; 161 client_list_t recursing; /*%< Recursing clients */ 162 163 uint8_t tcp_buffer[NS_CLIENT_TCP_BUFFER_SIZE]; 164 }; 165 166 /*% nameserver client structure */ 167 struct ns_client { 168 unsigned int magic; 169 ns_clientmgr_t *manager; 170 ns_clientstate_t state; 171 bool async; 172 unsigned int attributes; 173 dns_view_t *view; 174 dns_dispatch_t *dispatch; 175 isc_nmhandle_t *handle; /* Permanent pointer to handle */ 176 isc_nmhandle_t *sendhandle; /* Waiting for send callback */ 177 isc_nmhandle_t *reqhandle; /* Waiting for request callback 178 (query, update, notify) */ 179 isc_nmhandle_t *updatehandle; /* Waiting for update callback */ 180 isc_nmhandle_t *restarthandle; /* Waiting for restart callback */ 181 unsigned char *tcpbuf; 182 size_t tcpbuf_size; 183 dns_message_t *message; 184 dns_rdataset_t *opt; 185 dns_edectx_t edectx; 186 uint16_t udpsize; 187 uint16_t extflags; 188 int16_t ednsversion; /* -1 noedns */ 189 uint16_t additionaldepth; 190 uint16_t additionaltotal; 191 void (*cleanup)(ns_client_t *); 192 ns_query_t query; 193 isc_time_t requesttime; 194 isc_stdtime_t now; 195 isc_time_t tnow; 196 dns_name_t signername; /*%< [T]SIG key name */ 197 dns_name_t *signer; /*%< NULL if not valid sig */ 198 isc_result_t sigresult; 199 isc_result_t viewmatchresult; 200 isc_buffer_t *buffer; 201 isc_buffer_t tbuffer; 202 unsigned char *reqbuf; /*%< request copy for async path */ 203 size_t reqbuf_size; 204 205 isc_sockaddr_t peeraddr; 206 bool peeraddr_valid; 207 isc_netaddr_t destaddr; 208 isc_sockaddr_t destsockaddr; 209 210 dns_ecs_t ecs; /*%< EDNS client subnet sent by client */ 211 212 /*% 213 * Information about recent FORMERR response(s), for 214 * FORMERR loop avoidance. This is separate for each 215 * client object rather than global only to avoid 216 * the need for locking. 217 */ 218 struct { 219 isc_sockaddr_t addr; 220 isc_stdtime_t time; 221 dns_messageid_t id; 222 } formerrcache; 223 224 /*% Callback function to send a response when unit testing */ 225 void (*sendcb)(isc_buffer_t *buf); 226 227 ISC_LINK(ns_client_t) rlink; 228 unsigned char cookie[8]; 229 uint32_t expire; 230 unsigned char *keytag; 231 uint16_t keytag_len; 232 233 /*% 234 * Used to override the DNS response code in ns_client_error(). 235 * If set to -1, the rcode is determined from the result code, 236 * but if set to any other value, the least significant 12 237 * bits will be used as the rcode in the response message. 238 */ 239 int32_t rcode_override; 240 241 uint8_t sendbuf[NS_CLIENT_SEND_BUFFER_SIZE]; 242 }; 243 244 #define NS_CLIENT_MAGIC ISC_MAGIC('N', 'S', 'C', 'c') 245 #define NS_CLIENT_VALID(c) ISC_MAGIC_VALID(c, NS_CLIENT_MAGIC) 246 247 #define NS_CLIENTATTR_TCP 0x00001 248 #define NS_CLIENTATTR_RA 0x00002 /*%< Client gets recursive service */ 249 #define NS_CLIENTATTR_PKTINFO 0x00004 /*%< pktinfo is valid */ 250 #define NS_CLIENTATTR_MULTICAST 0x00008 /*%< recv'd from multicast */ 251 #define NS_CLIENTATTR_WANTDNSSEC 0x00010 /*%< include dnssec records */ 252 #define NS_CLIENTATTR_WANTNSID 0x00020 /*%< include nameserver ID */ 253 #define NS_CLIENTATTR_BADCOOKIE \ 254 0x00040 /*%< Presented cookie is bad/out-of-date */ 255 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA_RC 0x00080 */ 256 #define NS_CLIENTATTR_WANTAD 0x00100 /*%< want AD in response if possible */ 257 #define NS_CLIENTATTR_WANTCOOKIE 0x00200 /*%< return a COOKIE */ 258 #define NS_CLIENTATTR_HAVECOOKIE 0x00400 /*%< has a valid COOKIE */ 259 #define NS_CLIENTATTR_WANTEXPIRE 0x00800 /*%< return seconds to expire */ 260 #define NS_CLIENTATTR_HAVEEXPIRE 0x01000 /*%< return seconds to expire */ 261 #define NS_CLIENTATTR_WANTOPT 0x02000 /*%< add opt to reply */ 262 #define NS_CLIENTATTR_HAVEECS 0x04000 /*%< received an ECS option */ 263 #define NS_CLIENTATTR_WANTPAD 0x08000 /*%< pad reply */ 264 #define NS_CLIENTATTR_USEKEEPALIVE 0x10000 /*%< use TCP keepalive */ 265 266 #define NS_CLIENTATTR_NOSETFC 0x20000 /*%< don't set servfail cache */ 267 268 /* 269 * Flag to use with the SERVFAIL cache to indicate 270 * that a query had the CD bit set. 271 */ 272 #define NS_FAILCACHE_CD 0x01 273 274 #ifdef _LP64 275 extern atomic_uint_fast64_t ns_client_requests; 276 #else 277 extern atomic_uint_fast32_t ns_client_requests; 278 #endif 279 280 /*** 281 *** Functions 282 ***/ 283 284 /* 285 * Note! These ns_client_ routines MUST be called ONLY from the client's 286 * task in order to ensure synchronization. 287 */ 288 289 void 290 ns_client_send(ns_client_t *client); 291 /*%< 292 * Finish processing the current client request and 293 * send client->message as a response. 294 * \brief 295 * Note! These ns_client_ routines MUST be called ONLY from the client's 296 * task in order to ensure synchronization. 297 */ 298 299 void 300 ns_client_sendraw(ns_client_t *client, dns_message_t *msg); 301 /*%< 302 * Finish processing the current client request and 303 * send msg as a response using client->message->id for the id. 304 */ 305 306 void 307 ns_client_error(ns_client_t *client, isc_result_t result); 308 /*%< 309 * Finish processing the current client request and return 310 * an error response to the client. The error response 311 * will have an RCODE determined by 'result'. 312 */ 313 314 void 315 ns_client_drop(ns_client_t *client, isc_result_t result); 316 /*%< 317 * Log the reason the current client request has failed; no response 318 * will be sent. 319 */ 320 321 isc_result_t 322 ns_client_replace(ns_client_t *client); 323 /*%< 324 * Try to replace the current client with a new one, so that the 325 * current one can go off and do some lengthy work without 326 * leaving the dispatch/socket without service. 327 */ 328 329 void 330 ns_client_settimeout(ns_client_t *client, unsigned int seconds); 331 /*%< 332 * Set a timer in the client to go off in the specified amount of time. 333 */ 334 335 isc_result_t 336 ns_clientmgr_create(ns_server_t *sctx, isc_loopmgr_t *loopmgr, 337 dns_aclenv_t *aclenv, int tid, ns_clientmgr_t **managerp); 338 /*%< 339 * Create a client manager. 340 */ 341 342 void 343 ns_clientmgr_shutdown(ns_clientmgr_t *manager); 344 /*%< 345 * Shutdown a client manager and all ns_client_t objects 346 * managed by it 347 */ 348 349 isc_sockaddr_t * 350 ns_client_getsockaddr(ns_client_t *client); 351 /*%< 352 * Get the socket address of the client whose request is 353 * currently being processed. 354 */ 355 356 isc_sockaddr_t * 357 ns_client_getdestaddr(ns_client_t *client); 358 /*%< 359 * Get the destination address (server) for the request that is 360 * currently being processed. 361 */ 362 363 isc_result_t 364 ns_client_checkaclsilent(ns_client_t *client, isc_netaddr_t *netaddr, 365 dns_acl_t *acl, bool default_allow); 366 367 /*%< 368 * Convenience function for client request ACL checking. 369 * 370 * Check the current client request against 'acl'. If 'acl' 371 * is NULL, allow the request iff 'default_allow' is true. 372 * If netaddr is NULL, check the ACL against client->peeraddr; 373 * otherwise check it against netaddr. 374 * 375 * Notes: 376 *\li This is appropriate for checking allow-update, 377 * allow-query, allow-transfer, etc. It is not appropriate 378 * for checking the blackhole list because we treat positive 379 * matches as "allow" and negative matches as "deny"; in 380 * the case of the blackhole list this would be backwards. 381 * 382 * Requires: 383 *\li 'client' points to a valid client. 384 *\li 'netaddr' points to a valid address, or is NULL. 385 *\li 'acl' points to a valid ACL, or is NULL. 386 * 387 * Returns: 388 *\li ISC_R_SUCCESS if the request should be allowed 389 * \li DNS_R_REFUSED if the request should be denied 390 *\li No other return values are possible. 391 */ 392 393 isc_result_t 394 ns_client_checkacl(ns_client_t *client, isc_sockaddr_t *sockaddr, 395 const char *opname, dns_acl_t *acl, bool default_allow, 396 int log_level); 397 /*%< 398 * Like ns_client_checkaclsilent, except the outcome of the check is 399 * logged at log level 'log_level' if denied, and at debug 3 if approved. 400 * Log messages will refer to the request as an 'opname' request. 401 * 402 * Requires: 403 *\li 'client' points to a valid client. 404 *\li 'sockaddr' points to a valid address, or is NULL. 405 *\li 'acl' points to a valid ACL, or is NULL. 406 *\li 'opname' points to a null-terminated string. 407 */ 408 409 void 410 ns_client_log(ns_client_t *client, isc_logcategory_t *category, 411 isc_logmodule_t *module, int level, const char *fmt, ...) 412 ISC_FORMAT_PRINTF(5, 6); 413 414 void 415 ns_client_logv(ns_client_t *client, isc_logcategory_t *category, 416 isc_logmodule_t *module, int level, const char *fmt, va_list ap) 417 ISC_FORMAT_PRINTF(5, 0); 418 419 void 420 ns_client_aclmsg(const char *msg, const dns_name_t *name, dns_rdatatype_t type, 421 dns_rdataclass_t rdclass, char *buf, size_t len); 422 423 #define NS_CLIENT_ACLMSGSIZE(x) \ 424 (DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE + \ 425 DNS_RDATACLASS_FORMATSIZE + sizeof(x) + sizeof("'/'")) 426 427 void 428 ns_client_recursing(ns_client_t *client); 429 /*%< 430 * Add client to end of th recursing list. 431 */ 432 433 void 434 ns_client_killoldestquery(ns_client_t *client); 435 /*%< 436 * Kill the oldest recursive query (recursing list head). 437 */ 438 439 void 440 ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager); 441 /*%< 442 * Dump the outstanding recursive queries to 'f'. 443 */ 444 445 void 446 ns_client_qnamereplace(ns_client_t *client, dns_name_t *name); 447 /*%< 448 * Replace the qname. 449 */ 450 451 isc_result_t 452 ns_client_sourceip(dns_clientinfo_t *ci, isc_sockaddr_t **addrp); 453 454 isc_result_t 455 ns_client_addopt(ns_client_t *client, dns_message_t *message, 456 dns_rdataset_t **opt); 457 458 /*%< 459 * Get a client object from the inactive queue, or create one, as needed. 460 * (Not intended for use outside this module and associated tests.) 461 */ 462 463 void 464 ns_client_request(isc_nmhandle_t *handle, isc_result_t eresult, 465 isc_region_t *region, void *arg); 466 467 /*%< 468 * Handle client requests. 469 * (Not intended for use outside this module and associated tests.) 470 */ 471 472 isc_result_t 473 ns__client_tcpconn(isc_nmhandle_t *handle, isc_result_t result, void *arg); 474 475 /*%< 476 * Called every time a TCP connection is establish. This is used for 477 * updating TCP statistics. 478 */ 479 480 dns_rdataset_t * 481 ns_client_newrdataset(ns_client_t *client); 482 483 void 484 ns_client_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp); 485 /*%< 486 * Get and release temporary rdatasets in the client message; 487 * used in query.c and in plugins. 488 */ 489 490 isc_result_t 491 ns_client_newnamebuf(ns_client_t *client); 492 /*%< 493 * Allocate a name buffer for the client message. 494 */ 495 496 dns_name_t * 497 ns_client_newname(ns_client_t *client, isc_buffer_t *dbuf, isc_buffer_t *nbuf); 498 /*%< 499 * Get a temporary name for the client message. 500 */ 501 502 isc_buffer_t * 503 ns_client_getnamebuf(ns_client_t *client); 504 /*%< 505 * Get a name buffer from the pool, or allocate a new one if needed. 506 */ 507 508 void 509 ns_client_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf); 510 /*%< 511 * Adjust buffer 'dbuf' to reflect that 'name' is using space in it, 512 * and set client attributes appropriately. 513 */ 514 515 void 516 ns_client_releasename(ns_client_t *client, dns_name_t **namep); 517 /*%< 518 * Release 'name' back to the pool of temporary names for the client 519 * message. If it is using a name buffer, relinquish its exclusive 520 * rights on the buffer. 521 */ 522 523 isc_result_t 524 ns_client_newdbversion(ns_client_t *client, unsigned int n); 525 /*%< 526 * Allocate 'n' new database versions for use by client queries. 527 */ 528 529 ns_dbversion_t * 530 ns_client_getdbversion(ns_client_t *client); 531 /*%< 532 * Get a free database version for use by a client query, allocating 533 * a new one if necessary. 534 */ 535 536 ns_dbversion_t * 537 ns_client_findversion(ns_client_t *client, dns_db_t *db); 538 /*%< 539 * Find the correct database version to use with a client query. 540 * If we have already done a query related to the database 'db', 541 * make sure subsequent queries are from the same version; 542 * otherwise, take a database version from the list of dbversions 543 * allocated by ns_client_newdbversion(). 544 */ 545 546 ISC_REFCOUNT_DECL(ns_clientmgr); 547 548 void 549 ns__client_setup(ns_client_t *client, ns_clientmgr_t *manager, bool new); 550 /*%< 551 * Perform initial setup of an allocated client. 552 */ 553 554 void 555 ns__client_reset_cb(void *client0); 556 /*%< 557 * Reset the client object so that it can be reused. 558 */ 559 560 void 561 ns__client_put_cb(void *client0); 562 /*%< 563 * Free all resources allocated to this client object, so that 564 * it can be freed. 565 */ 566
Indexes created Sun Oct 04 00:26:11 UTC 2026