1 /* $NetBSD: client.h,v 1.19 2025/01/27 02:16:05 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_ednsopt_t *ede; 186 uint16_t udpsize; 187 uint16_t extflags; 188 int16_t ednsversion; /* -1 noedns */ 189 uint16_t additionaldepth; 190 void (*cleanup)(ns_client_t *); 191 ns_query_t query; 192 isc_time_t requesttime; 193 isc_stdtime_t now; 194 isc_time_t tnow; 195 dns_name_t signername; /*%< [T]SIG key name */ 196 dns_name_t *signer; /*%< NULL if not valid sig */ 197 isc_result_t sigresult; 198 isc_result_t viewmatchresult; 199 isc_buffer_t *buffer; 200 isc_buffer_t tbuffer; 201 202 isc_sockaddr_t peeraddr; 203 bool peeraddr_valid; 204 isc_netaddr_t destaddr; 205 isc_sockaddr_t destsockaddr; 206 207 dns_ecs_t ecs; /*%< EDNS client subnet sent by client */ 208 209 /*% 210 * Information about recent FORMERR response(s), for 211 * FORMERR loop avoidance. This is separate for each 212 * client object rather than global only to avoid 213 * the need for locking. 214 */ 215 struct { 216 isc_sockaddr_t addr; 217 isc_stdtime_t time; 218 dns_messageid_t id; 219 } formerrcache; 220 221 /*% Callback function to send a response when unit testing */ 222 void (*sendcb)(isc_buffer_t *buf); 223 224 ISC_LINK(ns_client_t) rlink; 225 unsigned char cookie[8]; 226 uint32_t expire; 227 unsigned char *keytag; 228 uint16_t keytag_len; 229 230 /*% 231 * Used to override the DNS response code in ns_client_error(). 232 * If set to -1, the rcode is determined from the result code, 233 * but if set to any other value, the least significant 12 234 * bits will be used as the rcode in the response message. 235 */ 236 int32_t rcode_override; 237 238 uint8_t sendbuf[NS_CLIENT_SEND_BUFFER_SIZE]; 239 }; 240 241 #define NS_CLIENT_MAGIC ISC_MAGIC('N', 'S', 'C', 'c') 242 #define NS_CLIENT_VALID(c) ISC_MAGIC_VALID(c, NS_CLIENT_MAGIC) 243 244 #define NS_CLIENTATTR_TCP 0x00001 245 #define NS_CLIENTATTR_RA 0x00002 /*%< Client gets recursive service */ 246 #define NS_CLIENTATTR_PKTINFO 0x00004 /*%< pktinfo is valid */ 247 #define NS_CLIENTATTR_MULTICAST 0x00008 /*%< recv'd from multicast */ 248 #define NS_CLIENTATTR_WANTDNSSEC 0x00010 /*%< include dnssec records */ 249 #define NS_CLIENTATTR_WANTNSID 0x00020 /*%< include nameserver ID */ 250 #define NS_CLIENTATTR_BADCOOKIE \ 251 0x00040 /*%< Presented cookie is bad/out-of-date */ 252 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA_RC 0x00080 */ 253 #define NS_CLIENTATTR_WANTAD 0x00100 /*%< want AD in response if possible */ 254 #define NS_CLIENTATTR_WANTCOOKIE 0x00200 /*%< return a COOKIE */ 255 #define NS_CLIENTATTR_HAVECOOKIE 0x00400 /*%< has a valid COOKIE */ 256 #define NS_CLIENTATTR_WANTEXPIRE 0x00800 /*%< return seconds to expire */ 257 #define NS_CLIENTATTR_HAVEEXPIRE 0x01000 /*%< return seconds to expire */ 258 #define NS_CLIENTATTR_WANTOPT 0x02000 /*%< add opt to reply */ 259 #define NS_CLIENTATTR_HAVEECS 0x04000 /*%< received an ECS option */ 260 #define NS_CLIENTATTR_WANTPAD 0x08000 /*%< pad reply */ 261 #define NS_CLIENTATTR_USEKEEPALIVE 0x10000 /*%< use TCP keepalive */ 262 263 #define NS_CLIENTATTR_NOSETFC 0x20000 /*%< don't set servfail cache */ 264 265 /* 266 * Flag to use with the SERVFAIL cache to indicate 267 * that a query had the CD bit set. 268 */ 269 #define NS_FAILCACHE_CD 0x01 270 271 #ifdef _LP64 272 extern atomic_uint_fast64_t ns_client_requests; 273 #else 274 extern atomic_uint_fast32_t ns_client_requests; 275 #endif 276 277 /*** 278 *** Functions 279 ***/ 280 281 /* 282 * Note! These ns_client_ routines MUST be called ONLY from the client's 283 * task in order to ensure synchronization. 284 */ 285 286 void 287 ns_client_send(ns_client_t *client); 288 /*%< 289 * Finish processing the current client request and 290 * send client->message as a response. 291 * \brief 292 * Note! These ns_client_ routines MUST be called ONLY from the client's 293 * task in order to ensure synchronization. 294 */ 295 296 void 297 ns_client_sendraw(ns_client_t *client, dns_message_t *msg); 298 /*%< 299 * Finish processing the current client request and 300 * send msg as a response using client->message->id for the id. 301 */ 302 303 void 304 ns_client_error(ns_client_t *client, isc_result_t result); 305 /*%< 306 * Finish processing the current client request and return 307 * an error response to the client. The error response 308 * will have an RCODE determined by 'result'. 309 */ 310 311 void 312 ns_client_extendederror(ns_client_t *client, uint16_t code, const char *text); 313 /*%< 314 * Set extended error with INFO-CODE <code> and EXTRA-TEXT <text>. 315 */ 316 317 void 318 ns_client_drop(ns_client_t *client, isc_result_t result); 319 /*%< 320 * Log the reason the current client request has failed; no response 321 * will be sent. 322 */ 323 324 isc_result_t 325 ns_client_replace(ns_client_t *client); 326 /*%< 327 * Try to replace the current client with a new one, so that the 328 * current one can go off and do some lengthy work without 329 * leaving the dispatch/socket without service. 330 */ 331 332 void 333 ns_client_settimeout(ns_client_t *client, unsigned int seconds); 334 /*%< 335 * Set a timer in the client to go off in the specified amount of time. 336 */ 337 338 isc_result_t 339 ns_clientmgr_create(ns_server_t *sctx, isc_loopmgr_t *loopmgr, 340 dns_aclenv_t *aclenv, int tid, ns_clientmgr_t **managerp); 341 /*%< 342 * Create a client manager. 343 */ 344 345 void 346 ns_clientmgr_shutdown(ns_clientmgr_t *manager); 347 /*%< 348 * Shutdown a client manager and all ns_client_t objects 349 * managed by it 350 */ 351 352 isc_sockaddr_t * 353 ns_client_getsockaddr(ns_client_t *client); 354 /*%< 355 * Get the socket address of the client whose request is 356 * currently being processed. 357 */ 358 359 isc_sockaddr_t * 360 ns_client_getdestaddr(ns_client_t *client); 361 /*%< 362 * Get the destination address (server) for the request that is 363 * currently being processed. 364 */ 365 366 isc_result_t 367 ns_client_checkaclsilent(ns_client_t *client, isc_netaddr_t *netaddr, 368 dns_acl_t *acl, bool default_allow); 369 370 /*%< 371 * Convenience function for client request ACL checking. 372 * 373 * Check the current client request against 'acl'. If 'acl' 374 * is NULL, allow the request iff 'default_allow' is true. 375 * If netaddr is NULL, check the ACL against client->peeraddr; 376 * otherwise check it against netaddr. 377 * 378 * Notes: 379 *\li This is appropriate for checking allow-update, 380 * allow-query, allow-transfer, etc. It is not appropriate 381 * for checking the blackhole list because we treat positive 382 * matches as "allow" and negative matches as "deny"; in 383 * the case of the blackhole list this would be backwards. 384 * 385 * Requires: 386 *\li 'client' points to a valid client. 387 *\li 'netaddr' points to a valid address, or is NULL. 388 *\li 'acl' points to a valid ACL, or is NULL. 389 * 390 * Returns: 391 *\li ISC_R_SUCCESS if the request should be allowed 392 * \li DNS_R_REFUSED if the request should be denied 393 *\li No other return values are possible. 394 */ 395 396 isc_result_t 397 ns_client_checkacl(ns_client_t *client, isc_sockaddr_t *sockaddr, 398 const char *opname, dns_acl_t *acl, bool default_allow, 399 int log_level); 400 /*%< 401 * Like ns_client_checkaclsilent, except the outcome of the check is 402 * logged at log level 'log_level' if denied, and at debug 3 if approved. 403 * Log messages will refer to the request as an 'opname' request. 404 * 405 * Requires: 406 *\li 'client' points to a valid client. 407 *\li 'sockaddr' points to a valid address, or is NULL. 408 *\li 'acl' points to a valid ACL, or is NULL. 409 *\li 'opname' points to a null-terminated string. 410 */ 411 412 void 413 ns_client_log(ns_client_t *client, isc_logcategory_t *category, 414 isc_logmodule_t *module, int level, const char *fmt, ...) 415 ISC_FORMAT_PRINTF(5, 6); 416 417 void 418 ns_client_logv(ns_client_t *client, isc_logcategory_t *category, 419 isc_logmodule_t *module, int level, const char *fmt, va_list ap) 420 ISC_FORMAT_PRINTF(5, 0); 421 422 void 423 ns_client_aclmsg(const char *msg, const dns_name_t *name, dns_rdatatype_t type, 424 dns_rdataclass_t rdclass, char *buf, size_t len); 425 426 #define NS_CLIENT_ACLMSGSIZE(x) \ 427 (DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE + \ 428 DNS_RDATACLASS_FORMATSIZE + sizeof(x) + sizeof("'/'")) 429 430 void 431 ns_client_recursing(ns_client_t *client); 432 /*%< 433 * Add client to end of th recursing list. 434 */ 435 436 void 437 ns_client_killoldestquery(ns_client_t *client); 438 /*%< 439 * Kill the oldest recursive query (recursing list head). 440 */ 441 442 void 443 ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager); 444 /*%< 445 * Dump the outstanding recursive queries to 'f'. 446 */ 447 448 void 449 ns_client_qnamereplace(ns_client_t *client, dns_name_t *name); 450 /*%< 451 * Replace the qname. 452 */ 453 454 isc_result_t 455 ns_client_sourceip(dns_clientinfo_t *ci, isc_sockaddr_t **addrp); 456 457 isc_result_t 458 ns_client_addopt(ns_client_t *client, dns_message_t *message, 459 dns_rdataset_t **opt); 460 461 /*%< 462 * Get a client object from the inactive queue, or create one, as needed. 463 * (Not intended for use outside this module and associated tests.) 464 */ 465 466 void 467 ns_client_request(isc_nmhandle_t *handle, isc_result_t eresult, 468 isc_region_t *region, void *arg); 469 470 /*%< 471 * Handle client requests. 472 * (Not intended for use outside this module and associated tests.) 473 */ 474 475 isc_result_t 476 ns__client_tcpconn(isc_nmhandle_t *handle, isc_result_t result, void *arg); 477 478 /*%< 479 * Called every time a TCP connection is establish. This is used for 480 * updating TCP statistics. 481 */ 482 483 dns_rdataset_t * 484 ns_client_newrdataset(ns_client_t *client); 485 486 void 487 ns_client_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp); 488 /*%< 489 * Get and release temporary rdatasets in the client message; 490 * used in query.c and in plugins. 491 */ 492 493 isc_result_t 494 ns_client_newnamebuf(ns_client_t *client); 495 /*%< 496 * Allocate a name buffer for the client message. 497 */ 498 499 dns_name_t * 500 ns_client_newname(ns_client_t *client, isc_buffer_t *dbuf, isc_buffer_t *nbuf); 501 /*%< 502 * Get a temporary name for the client message. 503 */ 504 505 isc_buffer_t * 506 ns_client_getnamebuf(ns_client_t *client); 507 /*%< 508 * Get a name buffer from the pool, or allocate a new one if needed. 509 */ 510 511 void 512 ns_client_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf); 513 /*%< 514 * Adjust buffer 'dbuf' to reflect that 'name' is using space in it, 515 * and set client attributes appropriately. 516 */ 517 518 void 519 ns_client_releasename(ns_client_t *client, dns_name_t **namep); 520 /*%< 521 * Release 'name' back to the pool of temporary names for the client 522 * message. If it is using a name buffer, relinquish its exclusive 523 * rights on the buffer. 524 */ 525 526 isc_result_t 527 ns_client_newdbversion(ns_client_t *client, unsigned int n); 528 /*%< 529 * Allocate 'n' new database versions for use by client queries. 530 */ 531 532 ns_dbversion_t * 533 ns_client_getdbversion(ns_client_t *client); 534 /*%< 535 * Get a free database version for use by a client query, allocating 536 * a new one if necessary. 537 */ 538 539 ns_dbversion_t * 540 ns_client_findversion(ns_client_t *client, dns_db_t *db); 541 /*%< 542 * Find the correct database version to use with a client query. 543 * If we have already done a query related to the database 'db', 544 * make sure subsequent queries are from the same version; 545 * otherwise, take a database version from the list of dbversions 546 * allocated by ns_client_newdbversion(). 547 */ 548 549 ISC_REFCOUNT_DECL(ns_clientmgr); 550 551 void 552 ns__client_setup(ns_client_t *client, ns_clientmgr_t *manager, bool new); 553 /*%< 554 * Perform initial setup of an allocated client. 555 */ 556 557 void 558 ns__client_reset_cb(void *client0); 559 /*%< 560 * Reset the client object so that it can be reused. 561 */ 562 563 void 564 ns__client_put_cb(void *client0); 565 /*%< 566 * Free all resources allocated to this client object, so that 567 * it can be freed. 568 */ 569