1 /* $NetBSD: client.h,v 1.11 2021/02/19 16:42:22 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * This Source Code Form is subject to the terms of the Mozilla Public 7 * License, v. 2.0. If a copy of the MPL was not distributed with this 8 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 9 * 10 * See the COPYRIGHT file distributed with this work for additional 11 * information regarding copyright ownership. 12 */ 13 14 #ifndef NS_CLIENT_H 15 #define NS_CLIENT_H 1 16 17 /***** 18 ***** Module Info 19 *****/ 20 21 /*! \file 22 * \brief 23 * This module defines two objects, ns_client_t and ns_clientmgr_t. 24 * 25 * An ns_client_t object handles incoming DNS requests from clients 26 * on a given network interface. 27 * 28 * Each ns_client_t object can handle only one TCP connection or UDP 29 * request at a time. Therefore, several ns_client_t objects are 30 * typically created to serve each network interface, e.g., one 31 * for handling TCP requests and a few (one per CPU) for handling 32 * UDP requests. 33 * 34 * Incoming requests are classified as queries, zone transfer 35 * requests, update requests, notify requests, etc, and handed off 36 * to the appropriate request handler. When the request has been 37 * fully handled (which can be much later), the ns_client_t must be 38 * notified of this by calling one of the following functions 39 * exactly once in the context of its task: 40 * \code 41 * ns_client_send() (sending a non-error response) 42 * ns_client_sendraw() (sending a raw response) 43 * ns_client_error() (sending an error response) 44 * ns_client_drop() (sending no response, logging the reason) 45 *\endcode 46 * This will release any resources used by the request and 47 * and allow the ns_client_t to listen for the next request. 48 * 49 * A ns_clientmgr_t manages a number of ns_client_t objects. 50 * New ns_client_t objects are created by calling 51 * ns_clientmgr_createclients(). They are destroyed by 52 * destroying their manager. 53 */ 54 55 /*** 56 *** Imports 57 ***/ 58 59 #include <inttypes.h> 60 #include <stdbool.h> 61 62 #include <isc/atomic.h> 63 #include <isc/buffer.h> 64 #include <isc/magic.h> 65 #include <isc/netmgr.h> 66 #include <isc/platform.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/tcpmsg.h> 77 #include <dns/types.h> 78 79 #include <ns/query.h> 80 #include <ns/types.h> 81 82 /*** 83 *** Types 84 ***/ 85 86 #define NS_CLIENT_TCP_BUFFER_SIZE 65535 87 #define NS_CLIENT_SEND_BUFFER_SIZE 4096 88 89 /*! 90 * Client object states. Ordering is significant: higher-numbered 91 * states are generally "more active", meaning that the client can 92 * have more dynamically allocated data, outstanding events, etc. 93 * In the list below, any such properties listed for state N 94 * also apply to any state > N. 95 */ 96 97 typedef enum { 98 NS_CLIENTSTATE_FREED = 0, 99 /*%< 100 * The client object no longer exists. 101 */ 102 103 NS_CLIENTSTATE_INACTIVE = 1, 104 /*%< 105 * The client object exists and has a task and timer. 106 * Its "query" struct and sendbuf are initialized. 107 * It has a message and OPT, both in the reset state. 108 */ 109 110 NS_CLIENTSTATE_READY = 2, 111 /*%< 112 * The client object is either a TCP or a UDP one, and 113 * it is associated with a network interface. It is on the 114 * client manager's list of active clients. 115 * 116 * If it is a TCP client object, it has a TCP listener socket 117 * and an outstanding TCP listen request. 118 * 119 * If it is a UDP client object, it has a UDP listener socket 120 * and an outstanding UDP receive request. 121 */ 122 123 NS_CLIENTSTATE_WORKING = 3, 124 /*%< 125 * The client object has received a request and is working 126 * on it. It has a view, and it may have any of a non-reset OPT, 127 * recursion quota, and an outstanding write request. 128 */ 129 130 NS_CLIENTSTATE_RECURSING = 4, 131 /*%< 132 * The client object is recursing. It will be on the 133 * 'recursing' list. 134 */ 135 136 NS_CLIENTSTATE_MAX = 5 137 /*%< 138 * Sentinel value used to indicate "no state". 139 */ 140 } ns_clientstate_t; 141 142 typedef ISC_LIST(ns_client_t) client_list_t; 143 144 /*% nameserver client manager structure */ 145 struct ns_clientmgr { 146 /* Unlocked. */ 147 unsigned int magic; 148 149 isc_mem_t * mctx; 150 ns_server_t * sctx; 151 isc_taskmgr_t * taskmgr; 152 isc_timermgr_t *timermgr; 153 isc_task_t * excl; 154 isc_refcount_t references; 155 int ncpus; 156 157 /* Attached by clients, needed for e.g. recursion */ 158 isc_task_t **taskpool; 159 160 ns_interface_t *interface; 161 162 /* Lock covers manager state. */ 163 isc_mutex_t lock; 164 bool exiting; 165 166 /* Lock covers the recursing list */ 167 isc_mutex_t reclock; 168 client_list_t recursing; /*%< Recursing clients */ 169 170 /*%< mctx pool for clients. */ 171 isc_mem_t **mctxpool; 172 }; 173 174 /*% nameserver client structure */ 175 struct ns_client { 176 unsigned int magic; 177 isc_mem_t * mctx; 178 bool allocated; /* Do we need to free it? */ 179 ns_server_t * sctx; 180 ns_clientmgr_t * manager; 181 ns_clientstate_t state; 182 int nupdates; 183 bool shuttingdown; 184 unsigned int attributes; 185 isc_task_t * task; 186 dns_view_t * view; 187 dns_dispatch_t * dispatch; 188 isc_nmhandle_t * handle; /* Permanent pointer to handle */ 189 isc_nmhandle_t * sendhandle; /* Waiting for send callback */ 190 isc_nmhandle_t * reqhandle; /* Waiting for request callback 191 (query, update, notify) */ 192 isc_nmhandle_t *fetchhandle; /* Waiting for recursive fetch */ 193 isc_nmhandle_t *prefetchhandle; /* Waiting for prefetch / rpzfetch */ 194 isc_nmhandle_t *updatehandle; /* Waiting for update callback */ 195 unsigned char * tcpbuf; 196 dns_message_t * message; 197 unsigned char * sendbuf; 198 dns_rdataset_t *opt; 199 uint16_t udpsize; 200 uint16_t extflags; 201 int16_t ednsversion; /* -1 noedns */ 202 void (*cleanup)(ns_client_t *); 203 void (*shutdown)(void *arg, isc_result_t result); 204 void * shutdown_arg; 205 ns_query_t query; 206 isc_time_t requesttime; 207 isc_stdtime_t now; 208 isc_time_t tnow; 209 dns_name_t signername; /*%< [T]SIG key name */ 210 dns_name_t * signer; /*%< NULL if not valid sig */ 211 bool mortal; /*%< Die after handling request */ 212 isc_quota_t * recursionquota; 213 214 isc_sockaddr_t peeraddr; 215 bool peeraddr_valid; 216 isc_netaddr_t destaddr; 217 isc_sockaddr_t destsockaddr; 218 219 dns_ecs_t ecs; /*%< EDNS client subnet sent by client */ 220 221 struct in6_pktinfo pktinfo; 222 isc_dscp_t dscp; 223 /*% 224 * Information about recent FORMERR response(s), for 225 * FORMERR loop avoidance. This is separate for each 226 * client object rather than global only to avoid 227 * the need for locking. 228 */ 229 struct { 230 isc_sockaddr_t addr; 231 isc_stdtime_t time; 232 dns_messageid_t id; 233 } formerrcache; 234 235 /*% Callback function to send a response when unit testing */ 236 void (*sendcb)(isc_buffer_t *buf); 237 238 ISC_LINK(ns_client_t) rlink; 239 unsigned char cookie[8]; 240 uint32_t expire; 241 unsigned char *keytag; 242 uint16_t keytag_len; 243 244 /*% 245 * Used to override the DNS response code in ns_client_error(). 246 * If set to -1, the rcode is determined from the result code, 247 * but if set to any other value, the least significant 12 248 * bits will be used as the rcode in the response message. 249 */ 250 int32_t rcode_override; 251 }; 252 253 #define NS_CLIENT_MAGIC ISC_MAGIC('N', 'S', 'C', 'c') 254 #define NS_CLIENT_VALID(c) ISC_MAGIC_VALID(c, NS_CLIENT_MAGIC) 255 256 #define NS_CLIENTATTR_TCP 0x00001 257 #define NS_CLIENTATTR_RA 0x00002 /*%< Client gets recursive service */ 258 #define NS_CLIENTATTR_PKTINFO 0x00004 /*%< pktinfo is valid */ 259 #define NS_CLIENTATTR_MULTICAST 0x00008 /*%< recv'd from multicast */ 260 #define NS_CLIENTATTR_WANTDNSSEC 0x00010 /*%< include dnssec records */ 261 #define NS_CLIENTATTR_WANTNSID 0x00020 /*%< include nameserver ID */ 262 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA 0x00040 */ 263 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA_RC 0x00080 */ 264 #define NS_CLIENTATTR_WANTAD 0x00100 /*%< want AD in response if possible */ 265 #define NS_CLIENTATTR_WANTCOOKIE 0x00200 /*%< return a COOKIE */ 266 #define NS_CLIENTATTR_HAVECOOKIE 0x00400 /*%< has a valid COOKIE */ 267 #define NS_CLIENTATTR_WANTEXPIRE 0x00800 /*%< return seconds to expire */ 268 #define NS_CLIENTATTR_HAVEEXPIRE 0x01000 /*%< return seconds to expire */ 269 #define NS_CLIENTATTR_WANTOPT 0x02000 /*%< add opt to reply */ 270 #define NS_CLIENTATTR_HAVEECS 0x04000 /*%< received an ECS option */ 271 #define NS_CLIENTATTR_WANTPAD 0x08000 /*%< pad reply */ 272 #define NS_CLIENTATTR_USEKEEPALIVE 0x10000 /*%< use TCP keepalive */ 273 274 #define NS_CLIENTATTR_NOSETFC 0x20000 /*%< don't set servfail cache */ 275 #define NS_CLIENTATTR_RECURSING 0x40000 /*%< client is recursing */ 276 277 /* 278 * Flag to use with the SERVFAIL cache to indicate 279 * that a query had the CD bit set. 280 */ 281 #define NS_FAILCACHE_CD 0x01 282 283 #if (defined(_WIN32) && !defined(_WIN64)) || !defined(_LP64) 284 LIBNS_EXTERNAL_DATA extern atomic_uint_fast32_t ns_client_requests; 285 #else /* if defined(_WIN32) && !defined(_WIN64) */ 286 LIBNS_EXTERNAL_DATA extern atomic_uint_fast64_t ns_client_requests; 287 #endif /* if defined(_WIN32) && !defined(_WIN64) */ 288 289 /*** 290 *** Functions 291 ***/ 292 293 /* 294 * Note! These ns_client_ routines MUST be called ONLY from the client's 295 * task in order to ensure synchronization. 296 */ 297 298 void 299 ns_client_send(ns_client_t *client); 300 /*%< 301 * Finish processing the current client request and 302 * send client->message as a response. 303 * \brief 304 * Note! These ns_client_ routines MUST be called ONLY from the client's 305 * task in order to ensure synchronization. 306 */ 307 308 void 309 ns_client_sendraw(ns_client_t *client, dns_message_t *msg); 310 /*%< 311 * Finish processing the current client request and 312 * send msg as a response using client->message->id for the id. 313 */ 314 315 void 316 ns_client_error(ns_client_t *client, isc_result_t result); 317 /*%< 318 * Finish processing the current client request and return 319 * an error response to the client. The error response 320 * will have an RCODE determined by 'result'. 321 */ 322 323 void 324 ns_client_drop(ns_client_t *client, isc_result_t result); 325 /*%< 326 * Log the reason the current client request has failed; no response 327 * will be sent. 328 */ 329 330 bool 331 ns_client_shuttingdown(ns_client_t *client); 332 /*%< 333 * Return true iff the client is currently shutting down. 334 */ 335 336 isc_result_t 337 ns_client_replace(ns_client_t *client); 338 /*%< 339 * Try to replace the current client with a new one, so that the 340 * current one can go off and do some lengthy work without 341 * leaving the dispatch/socket without service. 342 */ 343 344 void 345 ns_client_settimeout(ns_client_t *client, unsigned int seconds); 346 /*%< 347 * Set a timer in the client to go off in the specified amount of time. 348 */ 349 350 isc_result_t 351 ns_clientmgr_create(isc_mem_t *mctx, ns_server_t *sctx, isc_taskmgr_t *taskmgr, 352 isc_timermgr_t *timermgr, ns_interface_t *ifp, int ncpus, 353 ns_clientmgr_t **managerp); 354 /*%< 355 * Create a client manager. 356 */ 357 358 void 359 ns_clientmgr_destroy(ns_clientmgr_t **managerp); 360 /*%< 361 * Destroy a client manager and all ns_client_t objects 362 * managed by it. 363 */ 364 365 isc_sockaddr_t * 366 ns_client_getsockaddr(ns_client_t *client); 367 /*%< 368 * Get the socket address of the client whose request is 369 * currently being processed. 370 */ 371 372 isc_sockaddr_t * 373 ns_client_getdestaddr(ns_client_t *client); 374 /*%< 375 * Get the destination address (server) for the request that is 376 * currently being processed. 377 */ 378 379 isc_result_t 380 ns_client_checkaclsilent(ns_client_t *client, isc_netaddr_t *netaddr, 381 dns_acl_t *acl, bool default_allow); 382 383 /*%< 384 * Convenience function for client request ACL checking. 385 * 386 * Check the current client request against 'acl'. If 'acl' 387 * is NULL, allow the request iff 'default_allow' is true. 388 * If netaddr is NULL, check the ACL against client->peeraddr; 389 * otherwise check it against netaddr. 390 * 391 * Notes: 392 *\li This is appropriate for checking allow-update, 393 * allow-query, allow-transfer, etc. It is not appropriate 394 * for checking the blackhole list because we treat positive 395 * matches as "allow" and negative matches as "deny"; in 396 * the case of the blackhole list this would be backwards. 397 * 398 * Requires: 399 *\li 'client' points to a valid client. 400 *\li 'netaddr' points to a valid address, or is NULL. 401 *\li 'acl' points to a valid ACL, or is NULL. 402 * 403 * Returns: 404 *\li ISC_R_SUCCESS if the request should be allowed 405 * \li DNS_R_REFUSED if the request should be denied 406 *\li No other return values are possible. 407 */ 408 409 isc_result_t 410 ns_client_checkacl(ns_client_t *client, isc_sockaddr_t *sockaddr, 411 const char *opname, dns_acl_t *acl, bool default_allow, 412 int log_level); 413 /*%< 414 * Like ns_client_checkaclsilent, except the outcome of the check is 415 * logged at log level 'log_level' if denied, and at debug 3 if approved. 416 * Log messages will refer to the request as an 'opname' request. 417 * 418 * Requires: 419 *\li 'client' points to a valid client. 420 *\li 'sockaddr' points to a valid address, or is NULL. 421 *\li 'acl' points to a valid ACL, or is NULL. 422 *\li 'opname' points to a null-terminated string. 423 */ 424 425 void 426 ns_client_log(ns_client_t *client, isc_logcategory_t *category, 427 isc_logmodule_t *module, int level, const char *fmt, ...) 428 ISC_FORMAT_PRINTF(5, 6); 429 430 void 431 ns_client_logv(ns_client_t *client, isc_logcategory_t *category, 432 isc_logmodule_t *module, int level, const char *fmt, va_list ap) 433 ISC_FORMAT_PRINTF(5, 0); 434 435 void 436 ns_client_aclmsg(const char *msg, const dns_name_t *name, dns_rdatatype_t type, 437 dns_rdataclass_t rdclass, char *buf, size_t len); 438 439 #define NS_CLIENT_ACLMSGSIZE(x) \ 440 (DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE + \ 441 DNS_RDATACLASS_FORMATSIZE + sizeof(x) + sizeof("'/'")) 442 443 void 444 ns_client_recursing(ns_client_t *client); 445 /*%< 446 * Add client to end of th recursing list. 447 */ 448 449 void 450 ns_client_killoldestquery(ns_client_t *client); 451 /*%< 452 * Kill the oldest recursive query (recursing list head). 453 */ 454 455 void 456 ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager); 457 /*%< 458 * Dump the outstanding recursive queries to 'f'. 459 */ 460 461 void 462 ns_client_qnamereplace(ns_client_t *client, dns_name_t *name); 463 /*%< 464 * Replace the qname. 465 */ 466 467 isc_result_t 468 ns_client_sourceip(dns_clientinfo_t *ci, isc_sockaddr_t **addrp); 469 470 isc_result_t 471 ns_client_addopt(ns_client_t *client, dns_message_t *message, 472 dns_rdataset_t **opt); 473 474 /*%< 475 * Get a client object from the inactive queue, or create one, as needed. 476 * (Not intended for use outside this module and associated tests.) 477 */ 478 479 void 480 ns__client_request(isc_nmhandle_t *handle, isc_result_t eresult, 481 isc_region_t *region, void *arg); 482 483 /*%< 484 * Handle client requests. 485 * (Not intended for use outside this module and associated tests.) 486 */ 487 488 isc_result_t 489 ns__client_tcpconn(isc_nmhandle_t *handle, isc_result_t result, void *arg); 490 491 /*%< 492 * Called every time a TCP connection is establish. This is used for 493 * updating TCP statistics. 494 */ 495 496 dns_rdataset_t * 497 ns_client_newrdataset(ns_client_t *client); 498 499 void 500 ns_client_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp); 501 /*%< 502 * Get and release temporary rdatasets in the client message; 503 * used in query.c and in plugins. 504 */ 505 506 isc_result_t 507 ns_client_newnamebuf(ns_client_t *client); 508 /*%< 509 * Allocate a name buffer for the client message. 510 */ 511 512 dns_name_t * 513 ns_client_newname(ns_client_t *client, isc_buffer_t *dbuf, isc_buffer_t *nbuf); 514 /*%< 515 * Get a temporary name for the client message. 516 */ 517 518 isc_buffer_t * 519 ns_client_getnamebuf(ns_client_t *client); 520 /*%< 521 * Get a name buffer from the pool, or allocate a new one if needed. 522 */ 523 524 void 525 ns_client_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf); 526 /*%< 527 * Adjust buffer 'dbuf' to reflect that 'name' is using space in it, 528 * and set client attributes appropriately. 529 */ 530 531 void 532 ns_client_releasename(ns_client_t *client, dns_name_t **namep); 533 /*%< 534 * Release 'name' back to the pool of temporary names for the client 535 * message. If it is using a name buffer, relinquish its exclusive 536 * rights on the buffer. 537 */ 538 539 isc_result_t 540 ns_client_newdbversion(ns_client_t *client, unsigned int n); 541 /*%< 542 * Allocate 'n' new database versions for use by client queries. 543 */ 544 545 ns_dbversion_t * 546 ns_client_getdbversion(ns_client_t *client); 547 /*%< 548 * Get a free database version for use by a client query, allocating 549 * a new one if necessary. 550 */ 551 552 ns_dbversion_t * 553 ns_client_findversion(ns_client_t *client, dns_db_t *db); 554 /*%< 555 * Find the correct database version to use with a client query. 556 * If we have already done a query related to the database 'db', 557 * make sure subsequent queries are from the same version; 558 * otherwise, take a database version from the list of dbversions 559 * allocated by ns_client_newdbversion(). 560 */ 561 562 isc_result_t 563 ns__client_setup(ns_client_t *client, ns_clientmgr_t *manager, bool new); 564 /*%< 565 * Perform initial setup of an allocated client. 566 */ 567 568 void 569 ns__client_reset_cb(void *client0); 570 /*%< 571 * Reset the client object so that it can be reused. 572 */ 573 574 void 575 ns__client_put_cb(void *client0); 576 /*%< 577 * Free all resources allocated to this client object, so that 578 * it can be freed. 579 */ 580 581 #endif /* NS_CLIENT_H */ 582