1 /* $NetBSD: client.h,v 1.10 2020/08/03 17:23:43 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 http://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; 189 unsigned char * tcpbuf; 190 dns_message_t * message; 191 unsigned char * sendbuf; 192 dns_rdataset_t * opt; 193 uint16_t udpsize; 194 uint16_t extflags; 195 int16_t ednsversion; /* -1 noedns */ 196 void (*cleanup)(ns_client_t *); 197 void (*shutdown)(void *arg, isc_result_t result); 198 void * shutdown_arg; 199 ns_query_t query; 200 isc_time_t requesttime; 201 isc_stdtime_t now; 202 isc_time_t tnow; 203 dns_name_t signername; /*%< [T]SIG key name */ 204 dns_name_t * signer; /*%< NULL if not valid sig */ 205 bool mortal; /*%< Die after handling request */ 206 isc_quota_t * recursionquota; 207 208 isc_sockaddr_t peeraddr; 209 bool peeraddr_valid; 210 isc_netaddr_t destaddr; 211 isc_sockaddr_t destsockaddr; 212 213 dns_ecs_t ecs; /*%< EDNS client subnet sent by client */ 214 215 struct in6_pktinfo pktinfo; 216 isc_dscp_t dscp; 217 /*% 218 * Information about recent FORMERR response(s), for 219 * FORMERR loop avoidance. This is separate for each 220 * client object rather than global only to avoid 221 * the need for locking. 222 */ 223 struct { 224 isc_sockaddr_t addr; 225 isc_stdtime_t time; 226 dns_messageid_t id; 227 } formerrcache; 228 229 /*% Callback function to send a response when unit testing */ 230 void (*sendcb)(isc_buffer_t *buf); 231 232 ISC_LINK(ns_client_t) rlink; 233 unsigned char cookie[8]; 234 uint32_t expire; 235 unsigned char *keytag; 236 uint16_t keytag_len; 237 238 /*% 239 * Used to override the DNS response code in ns_client_error(). 240 * If set to -1, the rcode is determined from the result code, 241 * but if set to any other value, the least significant 12 242 * bits will be used as the rcode in the response message. 243 */ 244 int32_t rcode_override; 245 }; 246 247 #define NS_CLIENT_MAGIC ISC_MAGIC('N', 'S', 'C', 'c') 248 #define NS_CLIENT_VALID(c) ISC_MAGIC_VALID(c, NS_CLIENT_MAGIC) 249 250 #define NS_CLIENTATTR_TCP 0x00001 251 #define NS_CLIENTATTR_RA 0x00002 /*%< Client gets recursive service */ 252 #define NS_CLIENTATTR_PKTINFO 0x00004 /*%< pktinfo is valid */ 253 #define NS_CLIENTATTR_MULTICAST 0x00008 /*%< recv'd from multicast */ 254 #define NS_CLIENTATTR_WANTDNSSEC 0x00010 /*%< include dnssec records */ 255 #define NS_CLIENTATTR_WANTNSID 0x00020 /*%< include nameserver ID */ 256 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA 0x00040 */ 257 /* Obsolete: NS_CLIENTATTR_FILTER_AAAA_RC 0x00080 */ 258 #define NS_CLIENTATTR_WANTAD 0x00100 /*%< want AD in response if possible */ 259 #define NS_CLIENTATTR_WANTCOOKIE 0x00200 /*%< return a COOKIE */ 260 #define NS_CLIENTATTR_HAVECOOKIE 0x00400 /*%< has a valid COOKIE */ 261 #define NS_CLIENTATTR_WANTEXPIRE 0x00800 /*%< return seconds to expire */ 262 #define NS_CLIENTATTR_HAVEEXPIRE 0x01000 /*%< return seconds to expire */ 263 #define NS_CLIENTATTR_WANTOPT 0x02000 /*%< add opt to reply */ 264 #define NS_CLIENTATTR_HAVEECS 0x04000 /*%< received an ECS option */ 265 #define NS_CLIENTATTR_WANTPAD 0x08000 /*%< pad reply */ 266 #define NS_CLIENTATTR_USEKEEPALIVE 0x10000 /*%< use TCP keepalive */ 267 268 #define NS_CLIENTATTR_NOSETFC 0x20000 /*%< don't set servfail cache */ 269 270 /* 271 * Flag to use with the SERVFAIL cache to indicate 272 * that a query had the CD bit set. 273 */ 274 #define NS_FAILCACHE_CD 0x01 275 276 #if (defined(_WIN32) && !defined(_WIN64)) || !defined(_LP64) 277 LIBNS_EXTERNAL_DATA extern atomic_uint_fast32_t ns_client_requests; 278 #else /* if defined(_WIN32) && !defined(_WIN64) */ 279 LIBNS_EXTERNAL_DATA extern atomic_uint_fast64_t ns_client_requests; 280 #endif /* if defined(_WIN32) && !defined(_WIN64) */ 281 282 /*** 283 *** Functions 284 ***/ 285 286 /* 287 * Note! These ns_client_ routines MUST be called ONLY from the client's 288 * task in order to ensure synchronization. 289 */ 290 291 void 292 ns_client_send(ns_client_t *client); 293 /*%< 294 * Finish processing the current client request and 295 * send client->message as a response. 296 * \brief 297 * Note! These ns_client_ routines MUST be called ONLY from the client's 298 * task in order to ensure synchronization. 299 */ 300 301 void 302 ns_client_sendraw(ns_client_t *client, dns_message_t *msg); 303 /*%< 304 * Finish processing the current client request and 305 * send msg as a response using client->message->id for the id. 306 */ 307 308 void 309 ns_client_error(ns_client_t *client, isc_result_t result); 310 /*%< 311 * Finish processing the current client request and return 312 * an error response to the client. The error response 313 * will have an RCODE determined by 'result'. 314 */ 315 316 void 317 ns_client_drop(ns_client_t *client, isc_result_t result); 318 /*%< 319 * Log the reason the current client request has failed; no response 320 * will be sent. 321 */ 322 323 bool 324 ns_client_shuttingdown(ns_client_t *client); 325 /*%< 326 * Return true iff the client is currently shutting down. 327 */ 328 329 isc_result_t 330 ns_client_replace(ns_client_t *client); 331 /*%< 332 * Try to replace the current client with a new one, so that the 333 * current one can go off and do some lengthy work without 334 * leaving the dispatch/socket without service. 335 */ 336 337 void 338 ns_client_settimeout(ns_client_t *client, unsigned int seconds); 339 /*%< 340 * Set a timer in the client to go off in the specified amount of time. 341 */ 342 343 isc_result_t 344 ns_clientmgr_create(isc_mem_t *mctx, ns_server_t *sctx, isc_taskmgr_t *taskmgr, 345 isc_timermgr_t *timermgr, ns_interface_t *ifp, int ncpus, 346 ns_clientmgr_t **managerp); 347 /*%< 348 * Create a client manager. 349 */ 350 351 void 352 ns_clientmgr_destroy(ns_clientmgr_t **managerp); 353 /*%< 354 * Destroy a client manager and all ns_client_t objects 355 * managed by it. 356 */ 357 358 isc_sockaddr_t * 359 ns_client_getsockaddr(ns_client_t *client); 360 /*%< 361 * Get the socket address of the client whose request is 362 * currently being processed. 363 */ 364 365 isc_sockaddr_t * 366 ns_client_getdestaddr(ns_client_t *client); 367 /*%< 368 * Get the destination address (server) for the request that is 369 * currently being processed. 370 */ 371 372 isc_result_t 373 ns_client_checkaclsilent(ns_client_t *client, isc_netaddr_t *netaddr, 374 dns_acl_t *acl, bool default_allow); 375 376 /*%< 377 * Convenience function for client request ACL checking. 378 * 379 * Check the current client request against 'acl'. If 'acl' 380 * is NULL, allow the request iff 'default_allow' is true. 381 * If netaddr is NULL, check the ACL against client->peeraddr; 382 * otherwise check it against netaddr. 383 * 384 * Notes: 385 *\li This is appropriate for checking allow-update, 386 * allow-query, allow-transfer, etc. It is not appropriate 387 * for checking the blackhole list because we treat positive 388 * matches as "allow" and negative matches as "deny"; in 389 * the case of the blackhole list this would be backwards. 390 * 391 * Requires: 392 *\li 'client' points to a valid client. 393 *\li 'netaddr' points to a valid address, or is NULL. 394 *\li 'acl' points to a valid ACL, or is NULL. 395 * 396 * Returns: 397 *\li ISC_R_SUCCESS if the request should be allowed 398 * \li DNS_R_REFUSED if the request should be denied 399 *\li No other return values are possible. 400 */ 401 402 isc_result_t 403 ns_client_checkacl(ns_client_t *client, isc_sockaddr_t *sockaddr, 404 const char *opname, dns_acl_t *acl, bool default_allow, 405 int log_level); 406 /*%< 407 * Like ns_client_checkaclsilent, except the outcome of the check is 408 * logged at log level 'log_level' if denied, and at debug 3 if approved. 409 * Log messages will refer to the request as an 'opname' request. 410 * 411 * Requires: 412 *\li 'client' points to a valid client. 413 *\li 'sockaddr' points to a valid address, or is NULL. 414 *\li 'acl' points to a valid ACL, or is NULL. 415 *\li 'opname' points to a null-terminated string. 416 */ 417 418 void 419 ns_client_log(ns_client_t *client, isc_logcategory_t *category, 420 isc_logmodule_t *module, int level, const char *fmt, ...) 421 ISC_FORMAT_PRINTF(5, 6); 422 423 void 424 ns_client_logv(ns_client_t *client, isc_logcategory_t *category, 425 isc_logmodule_t *module, int level, const char *fmt, va_list ap) 426 ISC_FORMAT_PRINTF(5, 0); 427 428 void 429 ns_client_aclmsg(const char *msg, const dns_name_t *name, dns_rdatatype_t type, 430 dns_rdataclass_t rdclass, char *buf, size_t len); 431 432 #define NS_CLIENT_ACLMSGSIZE(x) \ 433 (DNS_NAME_FORMATSIZE + DNS_RDATATYPE_FORMATSIZE + \ 434 DNS_RDATACLASS_FORMATSIZE + sizeof(x) + sizeof("'/'")) 435 436 void 437 ns_client_recursing(ns_client_t *client); 438 /*%< 439 * Add client to end of th recursing list. 440 */ 441 442 void 443 ns_client_killoldestquery(ns_client_t *client); 444 /*%< 445 * Kill the oldest recursive query (recursing list head). 446 */ 447 448 void 449 ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager); 450 /*%< 451 * Dump the outstanding recursive queries to 'f'. 452 */ 453 454 void 455 ns_client_qnamereplace(ns_client_t *client, dns_name_t *name); 456 /*%< 457 * Replace the qname. 458 */ 459 460 isc_result_t 461 ns_client_sourceip(dns_clientinfo_t *ci, isc_sockaddr_t **addrp); 462 463 isc_result_t 464 ns_client_addopt(ns_client_t *client, dns_message_t *message, 465 dns_rdataset_t **opt); 466 467 /*%< 468 * Get a client object from the inactive queue, or create one, as needed. 469 * (Not intended for use outside this module and associated tests.) 470 */ 471 472 void 473 ns__client_request(isc_nmhandle_t *handle, isc_region_t *region, void *arg); 474 475 /*%< 476 * Handle client requests. 477 * (Not intended for use outside this module and associated tests.) 478 */ 479 480 isc_result_t 481 ns__client_tcpconn(isc_nmhandle_t *handle, isc_result_t result, void *arg); 482 483 /*%< 484 * Called every time a TCP connection is establish. This is used for 485 * updating TCP statistics. 486 */ 487 488 dns_rdataset_t * 489 ns_client_newrdataset(ns_client_t *client); 490 491 void 492 ns_client_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp); 493 /*%< 494 * Get and release temporary rdatasets in the client message; 495 * used in query.c and in plugins. 496 */ 497 498 isc_result_t 499 ns_client_newnamebuf(ns_client_t *client); 500 /*%< 501 * Allocate a name buffer for the client message. 502 */ 503 504 dns_name_t * 505 ns_client_newname(ns_client_t *client, isc_buffer_t *dbuf, isc_buffer_t *nbuf); 506 /*%< 507 * Get a temporary name for the client message. 508 */ 509 510 isc_buffer_t * 511 ns_client_getnamebuf(ns_client_t *client); 512 /*%< 513 * Get a name buffer from the pool, or allocate a new one if needed. 514 */ 515 516 void 517 ns_client_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf); 518 /*%< 519 * Adjust buffer 'dbuf' to reflect that 'name' is using space in it, 520 * and set client attributes appropriately. 521 */ 522 523 void 524 ns_client_releasename(ns_client_t *client, dns_name_t **namep); 525 /*%< 526 * Release 'name' back to the pool of temporary names for the client 527 * message. If it is using a name buffer, relinquish its exclusive 528 * rights on the buffer. 529 */ 530 531 isc_result_t 532 ns_client_newdbversion(ns_client_t *client, unsigned int n); 533 /*%< 534 * Allocate 'n' new database versions for use by client queries. 535 */ 536 537 ns_dbversion_t * 538 ns_client_getdbversion(ns_client_t *client); 539 /*%< 540 * Get a free database version for use by a client query, allocating 541 * a new one if necessary. 542 */ 543 544 ns_dbversion_t * 545 ns_client_findversion(ns_client_t *client, dns_db_t *db); 546 /*%< 547 * Find the correct database version to use with a client query. 548 * If we have already done a query related to the database 'db', 549 * make sure subsequent queries are from the same version; 550 * otherwise, take a database version from the list of dbversions 551 * allocated by ns_client_newdbversion(). 552 */ 553 554 isc_result_t 555 ns__client_setup(ns_client_t *client, ns_clientmgr_t *manager, bool new); 556 /*%< 557 * Perform initial setup of an allocated client. 558 */ 559 560 void 561 ns__client_reset_cb(void *client0); 562 /*%< 563 * Reset the client object so that it can be reused. 564 */ 565 566 void 567 ns__client_put_cb(void *client0); 568 /*%< 569 * Free all resources allocated to this client object, so that 570 * it can be freed. 571 */ 572 573 #endif /* NS_CLIENT_H */ 574