1 /* 2 * util/module.h - DNS handling module interface 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains the interface for DNS handling modules. 40 * 41 * The module interface uses the DNS modules as state machines. The 42 * state machines are activated in sequence to operate on queries. Once 43 * they are done, the reply is passed back. In the usual setup the mesh 44 * is the caller of the state machines and once things are done sends replies 45 * and invokes result callbacks. 46 * 47 * The module provides a number of functions, listed in the module_func_block. 48 * The module is inited and destroyed and memory usage queries, for the 49 * module as a whole, for entire-module state (such as a cache). And per-query 50 * functions are called, operate to move the state machine and cleanup of 51 * the per-query state. 52 * 53 * Most per-query state should simply be allocated in the query region. 54 * This is destroyed at the end of the query. 55 * 56 * The module environment contains services and information and caches 57 * shared by the modules and the rest of the system. It also contains 58 * function pointers for module-specific tasks (like sending queries). 59 * 60 * *** Example module calls for a normal query 61 * 62 * In this example, the query does not need recursion, all the other data 63 * can be found in the cache. This makes the example shorter. 64 * 65 * At the start of the program the iterator module is initialised. 66 * The iterator module sets up its global state, such as donotquery lists 67 * and private address trees. 68 * 69 * A query comes in, and a mesh entry is created for it. The mesh 70 * starts the resolution process. The validator module is the first 71 * in the list of modules, and it is started on this new query. The 72 * operate() function is called. The validator decides it needs not do 73 * anything yet until there is a result and returns wait_module, that 74 * causes the next module in the list to be started. 75 * 76 * The next module is the iterator. It is started on the passed query and 77 * decides to perform a lookup. For this simple example, the delegation 78 * point information is available, and all the iterator wants to do is 79 * send a UDP query. The iterator uses env.send_query() to send the 80 * query. Then the iterator suspends (returns from the operate call). 81 * 82 * When the UDP reply comes back (and on errors and timeouts), the 83 * operate function is called for the query, on the iterator module, 84 * with the event that there is a reply. The iterator decides that this 85 * is enough, the work is done. It returns the value finished from the 86 * operate call, which causes the previous module to be started. 87 * 88 * The previous module, the validator module, is started with the event 89 * that the iterator module is done. The validator decides to validate 90 * the query. Once it is done (which could take recursive lookups, but 91 * in this example no recursive lookups are needed), it returns from the 92 * operate function with finished. 93 * 94 * There is no previous module from the validator module, and the mesh 95 * takes this to mean that the query is finally done. The mesh invokes 96 * callbacks and sends packets to queriers. 97 * 98 * If other modules had been waiting (recursively) on the answer to this 99 * query, then the mesh will tell them about it. It calls the inform_super 100 * routine on all the waiting modules, and once that is done it calls all of 101 * them with the operate() call. During inform_super the query that is done 102 * still exists and information can be copied from it (but the module should 103 * not really re-entry codepoints and services). During the operate call 104 * the modules can use stored state to continue operation with the results. 105 * (network buffers are used to contain the answer packet during the 106 * inform_super phase, but after that the network buffers will be cleared 107 * of their contents so that other tasks can be performed). 108 * 109 * *** Example module calls for recursion 110 * 111 * A module is called in operate, and it decides that it wants to perform 112 * recursion. That is, it wants the full state-machine-list to operate on 113 * a different query. It calls env.attach_sub() to create a new query state. 114 * The routine returns the newly created state, and potentially the module 115 * can edit the module-states for the newly created query (i.e. pass along 116 * some information, like delegation points). The module then suspends, 117 * returns from the operate routine. 118 * 119 * The mesh meanwhile will have the newly created query (or queries) on 120 * a waiting list, and will call operate() on this query (or queries). 121 * It starts again at the start of the module list for them. The query 122 * (or queries) continue to operate their state machines, until they are 123 * done. When they are done the mesh calls inform_super on the module that 124 * wanted the recursion. After that the mesh calls operate() on the module 125 * that wanted to do the recursion, and during this phase the module could, 126 * for example, decide to create more recursions. 127 * 128 * If the module decides it no longer wants the recursive information 129 * it can call detach_subs. Those queries will still run to completion, 130 * potentially filling the cache with information. Inform_super is not 131 * called any more. 132 * 133 * The iterator module will fetch items from the cache, so a recursion 134 * attempt may complete very quickly if the item is in cache. The calling 135 * module has to wait for completion or eventual timeout. A recursive query 136 * that times out returns a servfail rcode (servfail is also returned for 137 * other errors during the lookup). 138 * 139 * Results are passed in the qstate, the rcode member is used to pass 140 * errors without requiring memory allocation, so that the code can continue 141 * in out-of-memory conditions. If the rcode member is 0 (NOERROR) then 142 * the dns_msg entry contains a filled out message. This message may 143 * also contain an rcode that is nonzero, but in this case additional 144 * information (query, additional) can be passed along. 145 * 146 * The rcode and dns_msg are used to pass the result from the the rightmost 147 * module towards the leftmost modules and then towards the user. 148 * 149 * If you want to avoid recursion-cycles where queries need other queries 150 * that need the first one, use detect_cycle() to see if that will happen. 151 * 152 */ 153 154 #ifndef UTIL_MODULE_H 155 #define UTIL_MODULE_H 156 #include "util/storage/lruhash.h" 157 #include "util/data/msgreply.h" 158 #include "util/data/msgparse.h" 159 struct sldns_buffer; 160 struct alloc_cache; 161 struct rrset_cache; 162 struct key_cache; 163 struct config_file; 164 struct slabhash; 165 struct query_info; 166 struct edns_data; 167 struct regional; 168 struct worker; 169 struct comm_base; 170 struct auth_zones; 171 struct outside_network; 172 struct module_qstate; 173 struct ub_randstate; 174 struct mesh_area; 175 struct mesh_state; 176 struct val_anchors; 177 struct val_neg_cache; 178 struct iter_forwards; 179 struct iter_hints; 180 struct respip_set; 181 struct respip_client_info; 182 struct respip_addr_info; 183 184 /** Maximum number of modules in operation */ 185 #define MAX_MODULE 16 186 187 /** Maximum number of known edns options */ 188 #define MAX_KNOWN_EDNS_OPTS 256 189 190 enum inplace_cb_list_type { 191 /* Inplace callbacks for when a resolved reply is ready to be sent to the 192 * front.*/ 193 inplace_cb_reply = 0, 194 /* Inplace callbacks for when a reply is given from the cache. */ 195 inplace_cb_reply_cache, 196 /* Inplace callbacks for when a reply is given with local data 197 * (or Chaos reply). */ 198 inplace_cb_reply_local, 199 /* Inplace callbacks for when the reply is servfail. */ 200 inplace_cb_reply_servfail, 201 /* Inplace callbacks for when a query is ready to be sent to the back.*/ 202 inplace_cb_query, 203 /* Inplace callback for when a reply is received from the back. */ 204 inplace_cb_query_response, 205 /* Inplace callback for when EDNS is parsed on a reply received from the 206 * back. */ 207 inplace_cb_edns_back_parsed, 208 /* Total number of types. Used for array initialization. 209 * Should always be last. */ 210 inplace_cb_types_total 211 }; 212 213 214 /** Known edns option. Can be populated during modules' init. */ 215 struct edns_known_option { 216 /** type of this edns option */ 217 uint16_t opt_code; 218 /** whether the option needs to bypass the cache stage */ 219 int bypass_cache_stage; 220 /** whether the option needs mesh aggregation */ 221 int no_aggregation; 222 }; 223 224 /** 225 * Inplace callback list of registered routines to be called. 226 */ 227 struct inplace_cb { 228 /** next in list */ 229 struct inplace_cb* next; 230 /** Inplace callback routine */ 231 void* cb; 232 void* cb_arg; 233 /** module id */ 234 int id; 235 }; 236 237 /** 238 * Inplace callback function called before replying. 239 * Called as func(qinfo, qstate, rep, rcode, edns, opt_list_out, repinfo, 240 * region, id, python_callback) 241 * Where: 242 * qinfo: the query info. 243 * qstate: the module state. NULL when calling before the query reaches the 244 * mesh states. 245 * rep: reply_info. Could be NULL. 246 * rcode: the return code. 247 * edns: the edns_data of the reply. When qstate is NULL, it is also used as 248 * the edns input. 249 * opt_list_out: the edns options list for the reply. 250 * repinfo: reply information for a communication point. NULL when calling 251 * during the mesh states; the same could be found from 252 * qstate->mesh_info->reply_list. 253 * region: region to store data. 254 * id: module id. 255 * python_callback: only used for registering a python callback function. 256 */ 257 typedef int inplace_cb_reply_func_type(struct query_info* qinfo, 258 struct module_qstate* qstate, struct reply_info* rep, int rcode, 259 struct edns_data* edns, struct edns_option** opt_list_out, 260 struct comm_reply* repinfo, struct regional* region, 261 struct timeval* start_time, int id, void* callback); 262 263 /** 264 * Inplace callback function called before sending the query to a nameserver. 265 * Called as func(qinfo, flags, qstate, addr, addrlen, zone, zonelen, region, 266 * id, python_callback) 267 * Where: 268 * qinfo: query info. 269 * flags: flags of the query. 270 * qstate: query state. 271 * addr: to which server to send the query. 272 * addrlen: length of addr. 273 * zone: name of the zone of the delegation point. wireformat dname. 274 * This is the delegation point name for which the server is deemed 275 * authoritative. 276 * zonelen: length of zone. 277 * region: region to store data. 278 * id: module id. 279 * python_callback: only used for registering a python callback function. 280 */ 281 typedef int inplace_cb_query_func_type(struct query_info* qinfo, uint16_t flags, 282 struct module_qstate* qstate, struct sockaddr_storage* addr, 283 socklen_t addrlen, uint8_t* zone, size_t zonelen, struct regional* region, 284 int id, void* callback); 285 286 /** 287 * Inplace callback function called after parsing edns on query reply. 288 * Called as func(qstate, id, cb_args) 289 * Where: 290 * qstate: the query state. 291 * id: module id. 292 * cb_args: argument passed when registering callback. 293 */ 294 typedef int inplace_cb_edns_back_parsed_func_type(struct module_qstate* qstate, 295 int id, void* cb_args); 296 297 /** 298 * Inplace callback function called after parsing query response. 299 * Called as func(qstate, response, id, cb_args) 300 * Where: 301 * qstate: the query state. 302 * response: query response. 303 * id: module id. 304 * cb_args: argument passed when registering callback. 305 */ 306 typedef int inplace_cb_query_response_func_type(struct module_qstate* qstate, 307 struct dns_msg* response, int id, void* cb_args); 308 309 /** 310 * Function called when looking for (expired) cached answers during the serve 311 * expired logic. 312 * Called as func(qstate, lookup_qinfo) 313 * Where: 314 * qstate: the query state. 315 * lookup_qinfo: the qinfo to lookup for. 316 */ 317 typedef struct dns_msg* serve_expired_lookup_func_type( 318 struct module_qstate* qstate, struct query_info* lookup_qinfo); 319 320 /** 321 * Module environment. 322 * Services and data provided to the module. 323 */ 324 struct module_env { 325 /* --- data --- */ 326 /** config file with config options */ 327 struct config_file* cfg; 328 /** shared message cache */ 329 struct slabhash* msg_cache; 330 /** shared rrset cache */ 331 struct rrset_cache* rrset_cache; 332 /** shared infrastructure cache (edns, lameness) */ 333 struct infra_cache* infra_cache; 334 /** shared key cache */ 335 struct key_cache* key_cache; 336 337 /* --- services --- */ 338 /** 339 * Send serviced DNS query to server. UDP/TCP and EDNS is handled. 340 * operate() should return with wait_reply. Later on a callback 341 * will cause operate() to be called with event timeout or reply. 342 * The time until a timeout is calculated from roundtrip timing, 343 * several UDP retries are attempted. 344 * @param qinfo: query info. 345 * @param flags: host order flags word, with opcode and CD bit. 346 * @param dnssec: if set, EDNS record will have bits set. 347 * If EDNS_DO bit is set, DO bit is set in EDNS records. 348 * If BIT_CD is set, CD bit is set in queries with EDNS records. 349 * @param want_dnssec: if set, the validator wants DNSSEC. Without 350 * EDNS, the answer is likely to be useless for this domain. 351 * @param nocaps: do not use caps_for_id, use the qname as given. 352 * (ignored if caps_for_id is disabled). 353 * @param addr: where to. 354 * @param addrlen: length of addr. 355 * @param zone: delegation point name. 356 * @param zonelen: length of zone name. 357 * @param ssl_upstream: use SSL for upstream queries. 358 * @param tls_auth_name: if ssl_upstream, use this name with TLS 359 * authentication. 360 * @param q: wich query state to reactivate upon return. 361 * @return: false on failure (memory or socket related). no query was 362 * sent. Or returns an outbound entry with qsent and qstate set. 363 * This outbound_entry will be used on later module invocations 364 * that involve this query (timeout, error or reply). 365 */ 366 struct outbound_entry* (*send_query)(struct query_info* qinfo, 367 uint16_t flags, int dnssec, int want_dnssec, int nocaps, 368 struct sockaddr_storage* addr, socklen_t addrlen, 369 uint8_t* zone, size_t zonelen, int ssl_upstream, 370 char* tls_auth_name, struct module_qstate* q); 371 372 /** 373 * Detach-subqueries. 374 * Remove all sub-query references from this query state. 375 * Keeps super-references of those sub-queries correct. 376 * Updates stat items in mesh_area structure. 377 * @param qstate: used to find mesh state. 378 */ 379 void (*detach_subs)(struct module_qstate* qstate); 380 381 /** 382 * Attach subquery. 383 * Creates it if it does not exist already. 384 * Keeps sub and super references correct. 385 * Updates stat items in mesh_area structure. 386 * Pass if it is priming query or not. 387 * return: 388 * o if error (malloc) happened. 389 * o need to initialise the new state (module init; it is a new state). 390 * so that the next run of the query with this module is successful. 391 * o no init needed, attachment successful. 392 * 393 * @param qstate: the state to find mesh state, and that wants to 394 * receive the results from the new subquery. 395 * @param qinfo: what to query for (copied). 396 * @param qflags: what flags to use (RD, CD flag or not). 397 * @param prime: if it is a (stub) priming query. 398 * @param valrec: validation lookup recursion, does not need validation 399 * @param newq: If the new subquery needs initialisation, it is 400 * returned, otherwise NULL is returned. 401 * @return: false on error, true if success (and init may be needed). 402 */ 403 int (*attach_sub)(struct module_qstate* qstate, 404 struct query_info* qinfo, uint16_t qflags, int prime, 405 int valrec, struct module_qstate** newq); 406 407 /** 408 * Add detached query. 409 * Creates it if it does not exist already. 410 * Does not make super/sub references. 411 * Performs a cycle detection - for double check - and fails if there is 412 * one. 413 * Updates stat items in mesh_area structure. 414 * Pass if it is priming query or not. 415 * return: 416 * o if error (malloc) happened. 417 * o need to initialise the new state (module init; it is a new state). 418 * so that the next run of the query with this module is successful. 419 * o no init needed, attachment successful. 420 * o added subquery, created if it did not exist already. 421 * 422 * @param qstate: the state to find mesh state, and that wants to receive 423 * the results from the new subquery. 424 * @param qinfo: what to query for (copied). 425 * @param qflags: what flags to use (RD / CD flag or not). 426 * @param prime: if it is a (stub) priming query. 427 * @param valrec: if it is a validation recursion query (lookup of key, DS). 428 * @param newq: If the new subquery needs initialisation, it is returned, 429 * otherwise NULL is returned. 430 * @param sub: The added mesh state, created if it did not exist already. 431 * @return: false on error, true if success (and init may be needed). 432 */ 433 int (*add_sub)(struct module_qstate* qstate, 434 struct query_info* qinfo, uint16_t qflags, int prime, 435 int valrec, struct module_qstate** newq, 436 struct mesh_state** sub); 437 438 /** 439 * Kill newly attached sub. If attach_sub returns newq for 440 * initialisation, but that fails, then this routine will cleanup and 441 * delete the freshly created sub. 442 * @param newq: the new subquery that is no longer needed. 443 * It is removed. 444 */ 445 void (*kill_sub)(struct module_qstate* newq); 446 447 /** 448 * Detect if adding a dependency for qstate on name,type,class will 449 * create a dependency cycle. 450 * @param qstate: given mesh querystate. 451 * @param qinfo: query info for dependency. 452 * @param flags: query flags of dependency, RD/CD flags. 453 * @param prime: if dependency is a priming query or not. 454 * @param valrec: validation lookup recursion, does not need validation 455 * @return true if the name,type,class exists and the given 456 * qstate mesh exists as a dependency of that name. Thus 457 * if qstate becomes dependent on name,type,class then a 458 * cycle is created. 459 */ 460 int (*detect_cycle)(struct module_qstate* qstate, 461 struct query_info* qinfo, uint16_t flags, int prime, 462 int valrec); 463 464 /** region for temporary usage. May be cleared after operate() call. */ 465 struct regional* scratch; 466 /** buffer for temporary usage. May be cleared after operate() call. */ 467 struct sldns_buffer* scratch_buffer; 468 /** internal data for daemon - worker thread. */ 469 struct worker* worker; 470 /** the worker event base */ 471 struct comm_base* worker_base; 472 /** the outside network */ 473 struct outside_network* outnet; 474 /** mesh area with query state dependencies */ 475 struct mesh_area* mesh; 476 /** allocation service */ 477 struct alloc_cache* alloc; 478 /** random table to generate random numbers */ 479 struct ub_randstate* rnd; 480 /** time in seconds, converted to integer */ 481 time_t* now; 482 /** time in microseconds. Relatively recent. */ 483 struct timeval* now_tv; 484 /** is validation required for messages, controls client-facing 485 * validation status (AD bits) and servfails */ 486 int need_to_validate; 487 /** trusted key storage; these are the configured keys, if not NULL, 488 * otherwise configured by validator. These are the trust anchors, 489 * and are not primed and ready for validation, but on the bright 490 * side, they are read only memory, thus no locks and fast. */ 491 struct val_anchors* anchors; 492 /** negative cache, configured by the validator. if not NULL, 493 * contains NSEC record lookup trees. */ 494 struct val_neg_cache* neg_cache; 495 /** the 5011-probe timer (if any) */ 496 struct comm_timer* probe_timer; 497 /** auth zones */ 498 struct auth_zones* auth_zones; 499 /** Mapping of forwarding zones to targets. 500 * iterator forwarder information. per-thread, created by worker */ 501 struct iter_forwards* fwds; 502 /** 503 * iterator forwarder information. per-thread, created by worker. 504 * The hints -- these aren't stored in the cache because they don't 505 * expire. The hints are always used to "prime" the cache. Note 506 * that both root hints and stub zone "hints" are stored in this 507 * data structure. 508 */ 509 struct iter_hints* hints; 510 /** module specific data. indexed by module id. */ 511 void* modinfo[MAX_MODULE]; 512 513 /* Shared linked list of inplace callback functions */ 514 struct inplace_cb* inplace_cb_lists[inplace_cb_types_total]; 515 516 /** 517 * Shared array of known edns options (size MAX_KNOWN_EDNS_OPTS). 518 * Filled by edns literate modules during init. 519 */ 520 struct edns_known_option* edns_known_options; 521 /* Number of known edns options */ 522 size_t edns_known_options_num; 523 /** EDNS client string information */ 524 struct edns_strings* edns_strings; 525 526 /* Make every mesh state unique, do not aggregate mesh states. */ 527 int unique_mesh; 528 }; 529 530 /** 531 * External visible states of the module state machine 532 * Modules may also have an internal state. 533 * Modules are supposed to run to completion or until blocked. 534 */ 535 enum module_ext_state { 536 /** initial state - new query */ 537 module_state_initial = 0, 538 /** waiting for reply to outgoing network query */ 539 module_wait_reply, 540 /** module is waiting for another module */ 541 module_wait_module, 542 /** module is waiting for another module; that other is restarted */ 543 module_restart_next, 544 /** module is waiting for sub-query */ 545 module_wait_subquery, 546 /** module could not finish the query */ 547 module_error, 548 /** module is finished with query */ 549 module_finished 550 }; 551 552 /** 553 * Events that happen to modules, that start or wakeup modules. 554 */ 555 enum module_ev { 556 /** new query */ 557 module_event_new = 0, 558 /** query passed by other module */ 559 module_event_pass, 560 /** reply inbound from server */ 561 module_event_reply, 562 /** no reply, timeout or other error */ 563 module_event_noreply, 564 /** reply is there, but capitalisation check failed */ 565 module_event_capsfail, 566 /** next module is done, and its reply is awaiting you */ 567 module_event_moddone, 568 /** error */ 569 module_event_error 570 }; 571 572 /** 573 * Linked list of sockaddrs 574 * May be allocated such that only 'len' bytes of addr exist for the structure. 575 */ 576 struct sock_list { 577 /** next in list */ 578 struct sock_list* next; 579 /** length of addr */ 580 socklen_t len; 581 /** sockaddr */ 582 struct sockaddr_storage addr; 583 }; 584 585 struct respip_action_info; 586 587 /** 588 * Struct to hold relevant data for serve expired 589 */ 590 struct serve_expired_data { 591 struct comm_timer* timer; 592 serve_expired_lookup_func_type* get_cached_answer; 593 }; 594 595 /** 596 * Module state, per query. 597 */ 598 struct module_qstate { 599 /** which query is being answered: name, type, class */ 600 struct query_info qinfo; 601 /** flags uint16 from query */ 602 uint16_t query_flags; 603 /** if this is a (stub or root) priming query (with hints) */ 604 int is_priming; 605 /** if this is a validation recursion query that does not get 606 * validation itself */ 607 int is_valrec; 608 609 /** comm_reply contains server replies */ 610 struct comm_reply* reply; 611 /** the reply message, with message for client and calling module */ 612 struct dns_msg* return_msg; 613 /** the rcode, in case of error, instead of a reply message */ 614 int return_rcode; 615 /** origin of the reply (can be NULL from cache, list for cnames) */ 616 struct sock_list* reply_origin; 617 /** IP blacklist for queries */ 618 struct sock_list* blacklist; 619 /** region for this query. Cleared when query process finishes. */ 620 struct regional* region; 621 /** failure reason information if val-log-level is high */ 622 struct config_strlist* errinf; 623 624 /** which module is executing */ 625 int curmod; 626 /** module states */ 627 enum module_ext_state ext_state[MAX_MODULE]; 628 /** module specific data for query. indexed by module id. */ 629 void* minfo[MAX_MODULE]; 630 /** environment for this query */ 631 struct module_env* env; 632 /** mesh related information for this query */ 633 struct mesh_state* mesh_info; 634 /** how many seconds before expiry is this prefetched (0 if not) */ 635 time_t prefetch_leeway; 636 /** serve expired data */ 637 struct serve_expired_data* serve_expired_data; 638 639 /** incoming edns options from the front end */ 640 struct edns_option* edns_opts_front_in; 641 /** outgoing edns options to the back end */ 642 struct edns_option* edns_opts_back_out; 643 /** incoming edns options from the back end */ 644 struct edns_option* edns_opts_back_in; 645 /** outgoing edns options to the front end */ 646 struct edns_option* edns_opts_front_out; 647 /** whether modules should answer from the cache */ 648 int no_cache_lookup; 649 /** whether modules should store answer in the cache */ 650 int no_cache_store; 651 /** whether to refetch a fresh answer on finishing this state*/ 652 int need_refetch; 653 /** whether the query (or a subquery) was ratelimited */ 654 int was_ratelimited; 655 656 /** 657 * Attributes of clients that share the qstate that may affect IP-based 658 * actions. 659 */ 660 struct respip_client_info* client_info; 661 662 /** Extended result of response-ip action processing, mainly 663 * for logging purposes. */ 664 struct respip_action_info* respip_action_info; 665 666 /** whether the reply should be dropped */ 667 int is_drop; 668 }; 669 670 /** 671 * Module functionality block 672 */ 673 struct module_func_block { 674 /** text string name of module */ 675 const char* name; 676 677 /** 678 * init the module. Called once for the global state. 679 * This is the place to apply settings from the config file. 680 * @param env: module environment. 681 * @param id: module id number. 682 * return: 0 on error 683 */ 684 int (*init)(struct module_env* env, int id); 685 686 /** 687 * de-init, delete, the module. Called once for the global state. 688 * @param env: module environment. 689 * @param id: module id number. 690 */ 691 void (*deinit)(struct module_env* env, int id); 692 693 /** 694 * accept a new query, or work further on existing query. 695 * Changes the qstate->ext_state to be correct on exit. 696 * @param ev: event that causes the module state machine to 697 * (re-)activate. 698 * @param qstate: the query state. 699 * Note that this method is not allowed to change the 700 * query state 'identity', that is query info, qflags, 701 * and priming status. 702 * Attach a subquery to get results to a different query. 703 * @param id: module id number that operate() is called on. 704 * @param outbound: if not NULL this event is due to the reply/timeout 705 * or error on this outbound query. 706 * @return: if at exit the ext_state is: 707 * o wait_module: next module is started. (with pass event). 708 * o error or finished: previous module is resumed. 709 * o otherwise it waits until that event happens (assumes 710 * the service routine to make subrequest or send message 711 * have been called. 712 */ 713 void (*operate)(struct module_qstate* qstate, enum module_ev event, 714 int id, struct outbound_entry* outbound); 715 716 /** 717 * inform super querystate about the results from this subquerystate. 718 * Is called when the querystate is finished. The method invoked is 719 * the one from the current module active in the super querystate. 720 * @param qstate: the query state that is finished. 721 * Examine return_rcode and return_reply in the qstate. 722 * @param id: module id for this module. 723 * This coincides with the current module for the super qstate. 724 * @param super: the super querystate that needs to be informed. 725 */ 726 void (*inform_super)(struct module_qstate* qstate, int id, 727 struct module_qstate* super); 728 729 /** 730 * clear module specific data 731 */ 732 void (*clear)(struct module_qstate* qstate, int id); 733 734 /** 735 * How much memory is the module specific data using. 736 * @param env: module environment. 737 * @param id: the module id. 738 * @return the number of bytes that are alloced. 739 */ 740 size_t (*get_mem)(struct module_env* env, int id); 741 }; 742 743 /** 744 * Debug utility: module external qstate to string 745 * @param s: the state value. 746 * @return descriptive string. 747 */ 748 const char* strextstate(enum module_ext_state s); 749 750 /** 751 * Debug utility: module event to string 752 * @param e: the module event value. 753 * @return descriptive string. 754 */ 755 const char* strmodulevent(enum module_ev e); 756 757 /** 758 * Initialize the edns known options by allocating the required space. 759 * @param env: the module environment. 760 * @return false on failure (no memory). 761 */ 762 int edns_known_options_init(struct module_env* env); 763 764 /** 765 * Free the allocated space for the known edns options. 766 * @param env: the module environment. 767 */ 768 void edns_known_options_delete(struct module_env* env); 769 770 /** 771 * Register a known edns option. Overwrite the flags if it is already 772 * registered. Used before creating workers to register known edns options. 773 * @param opt_code: the edns option code. 774 * @param bypass_cache_stage: whether the option interacts with the cache. 775 * @param no_aggregation: whether the option implies more specific 776 * aggregation. 777 * @param env: the module environment. 778 * @return true on success, false on failure (registering more options than 779 * allowed or trying to register after the environment is copied to the 780 * threads.) 781 */ 782 int edns_register_option(uint16_t opt_code, int bypass_cache_stage, 783 int no_aggregation, struct module_env* env); 784 785 /** 786 * Register an inplace callback function. 787 * @param cb: pointer to the callback function. 788 * @param type: inplace callback type. 789 * @param cbarg: argument for the callback function, or NULL. 790 * @param env: the module environment. 791 * @param id: module id. 792 * @return true on success, false on failure (out of memory or trying to 793 * register after the environment is copied to the threads.) 794 */ 795 int 796 inplace_cb_register(void* cb, enum inplace_cb_list_type type, void* cbarg, 797 struct module_env* env, int id); 798 799 /** 800 * Delete callback for specified type and module id. 801 * @param env: the module environment. 802 * @param type: inplace callback type. 803 * @param id: module id. 804 */ 805 void 806 inplace_cb_delete(struct module_env* env, enum inplace_cb_list_type type, 807 int id); 808 809 /** 810 * Delete all the inplace callback linked lists. 811 * @param env: the module environment. 812 */ 813 void inplace_cb_lists_delete(struct module_env* env); 814 815 /** 816 * Check if an edns option is known. 817 * @param opt_code: the edns option code. 818 * @param env: the module environment. 819 * @return pointer to registered option if the edns option is known, 820 * NULL otherwise. 821 */ 822 struct edns_known_option* edns_option_is_known(uint16_t opt_code, 823 struct module_env* env); 824 825 /** 826 * Check if an edns option needs to bypass the reply from cache stage. 827 * @param list: the edns options. 828 * @param env: the module environment. 829 * @return true if an edns option needs to bypass the cache stage, 830 * false otherwise. 831 */ 832 int edns_bypass_cache_stage(struct edns_option* list, 833 struct module_env* env); 834 835 /** 836 * Check if an unique mesh state is required. Might be triggered by EDNS option 837 * or set for the complete env. 838 * @param list: the edns options. 839 * @param env: the module environment. 840 * @return true if an edns option needs a unique mesh state, 841 * false otherwise. 842 */ 843 int unique_mesh_state(struct edns_option* list, struct module_env* env); 844 845 /** 846 * Log the known edns options. 847 * @param level: the desired verbosity level. 848 * @param env: the module environment. 849 */ 850 void log_edns_known_options(enum verbosity_value level, 851 struct module_env* env); 852 853 /** 854 * Copy state that may have happened in the subquery and is always relevant to 855 * the super. 856 * @param qstate: query state that finished. 857 * @param id: module id. 858 * @param super: the qstate to inform. 859 */ 860 void copy_state_to_super(struct module_qstate* qstate, int id, 861 struct module_qstate* super); 862 863 #endif /* UTIL_MODULE_H */ 864