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(edns, qstate, opt_list_out, qinfo, reply_info, rcode, 240 * region, 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 * region: region to store data. 251 * python_callback: only used for registering a python callback function. 252 */ 253 typedef int inplace_cb_reply_func_type(struct query_info* qinfo, 254 struct module_qstate* qstate, struct reply_info* rep, int rcode, 255 struct edns_data* edns, struct edns_option** opt_list_out, 256 struct regional* region, int id, void* callback); 257 258 /** 259 * Inplace callback function called before sending the query to a nameserver. 260 * Called as func(qinfo, flags, qstate, addr, addrlen, zone, zonelen, region, 261 * python_callback) 262 * Where: 263 * qinfo: query info. 264 * flags: flags of the query. 265 * qstate: query state. 266 * addr: to which server to send the query. 267 * addrlen: length of addr. 268 * zone: name of the zone of the delegation point. wireformat dname. 269 * This is the delegation point name for which the server is deemed 270 * authoritative. 271 * zonelen: length of zone. 272 * region: region to store data. 273 * python_callback: only used for registering a python callback function. 274 */ 275 typedef int inplace_cb_query_func_type(struct query_info* qinfo, uint16_t flags, 276 struct module_qstate* qstate, struct sockaddr_storage* addr, 277 socklen_t addrlen, uint8_t* zone, size_t zonelen, struct regional* region, 278 int id, void* callback); 279 280 /** 281 * Inplace callback function called after parsing edns on query reply. 282 * Called as func(qstate, cb_args) 283 * Where: 284 * qstate: the query state 285 * id: module id 286 * cb_args: argument passed when registering callback. 287 */ 288 typedef int inplace_cb_edns_back_parsed_func_type(struct module_qstate* qstate, 289 int id, void* cb_args); 290 291 /** 292 * Inplace callback function called after parsing query response. 293 * Called as func(qstate, id, cb_args) 294 * Where: 295 * qstate: the query state 296 * response: query response 297 * id: module id 298 * cb_args: argument passed when registering callback. 299 */ 300 typedef int inplace_cb_query_response_func_type(struct module_qstate* qstate, 301 struct dns_msg* response, int id, void* cb_args); 302 303 /** 304 * Module environment. 305 * Services and data provided to the module. 306 */ 307 struct module_env { 308 /* --- data --- */ 309 /** config file with config options */ 310 struct config_file* cfg; 311 /** shared message cache */ 312 struct slabhash* msg_cache; 313 /** shared rrset cache */ 314 struct rrset_cache* rrset_cache; 315 /** shared infrastructure cache (edns, lameness) */ 316 struct infra_cache* infra_cache; 317 /** shared key cache */ 318 struct key_cache* key_cache; 319 320 /* --- services --- */ 321 /** 322 * Send serviced DNS query to server. UDP/TCP and EDNS is handled. 323 * operate() should return with wait_reply. Later on a callback 324 * will cause operate() to be called with event timeout or reply. 325 * The time until a timeout is calculated from roundtrip timing, 326 * several UDP retries are attempted. 327 * @param qinfo: query info. 328 * @param flags: host order flags word, with opcode and CD bit. 329 * @param dnssec: if set, EDNS record will have bits set. 330 * If EDNS_DO bit is set, DO bit is set in EDNS records. 331 * If BIT_CD is set, CD bit is set in queries with EDNS records. 332 * @param want_dnssec: if set, the validator wants DNSSEC. Without 333 * EDNS, the answer is likely to be useless for this domain. 334 * @param nocaps: do not use caps_for_id, use the qname as given. 335 * (ignored if caps_for_id is disabled). 336 * @param addr: where to. 337 * @param addrlen: length of addr. 338 * @param zone: delegation point name. 339 * @param zonelen: length of zone name. 340 * @param ssl_upstream: use SSL for upstream queries. 341 * @param tls_auth_name: if ssl_upstream, use this name with TLS 342 * authentication. 343 * @param q: wich query state to reactivate upon return. 344 * @return: false on failure (memory or socket related). no query was 345 * sent. Or returns an outbound entry with qsent and qstate set. 346 * This outbound_entry will be used on later module invocations 347 * that involve this query (timeout, error or reply). 348 */ 349 struct outbound_entry* (*send_query)(struct query_info* qinfo, 350 uint16_t flags, int dnssec, int want_dnssec, int nocaps, 351 struct sockaddr_storage* addr, socklen_t addrlen, 352 uint8_t* zone, size_t zonelen, int ssl_upstream, 353 char* tls_auth_name, struct module_qstate* q); 354 355 /** 356 * Detach-subqueries. 357 * Remove all sub-query references from this query state. 358 * Keeps super-references of those sub-queries correct. 359 * Updates stat items in mesh_area structure. 360 * @param qstate: used to find mesh state. 361 */ 362 void (*detach_subs)(struct module_qstate* qstate); 363 364 /** 365 * Attach subquery. 366 * Creates it if it does not exist already. 367 * Keeps sub and super references correct. 368 * Updates stat items in mesh_area structure. 369 * Pass if it is priming query or not. 370 * return: 371 * o if error (malloc) happened. 372 * o need to initialise the new state (module init; it is a new state). 373 * so that the next run of the query with this module is successful. 374 * o no init needed, attachment successful. 375 * 376 * @param qstate: the state to find mesh state, and that wants to 377 * receive the results from the new subquery. 378 * @param qinfo: what to query for (copied). 379 * @param qflags: what flags to use (RD, CD flag or not). 380 * @param prime: if it is a (stub) priming query. 381 * @param valrec: validation lookup recursion, does not need validation 382 * @param newq: If the new subquery needs initialisation, it is 383 * returned, otherwise NULL is returned. 384 * @return: false on error, true if success (and init may be needed). 385 */ 386 int (*attach_sub)(struct module_qstate* qstate, 387 struct query_info* qinfo, uint16_t qflags, int prime, 388 int valrec, struct module_qstate** newq); 389 390 /** 391 * Add detached query. 392 * Creates it if it does not exist already. 393 * Does not make super/sub references. 394 * Performs a cycle detection - for double check - and fails if there is 395 * one. 396 * Updates stat items in mesh_area structure. 397 * Pass if it is priming query or not. 398 * return: 399 * o if error (malloc) happened. 400 * o need to initialise the new state (module init; it is a new state). 401 * so that the next run of the query with this module is successful. 402 * o no init needed, attachment successful. 403 * o added subquery, created if it did not exist already. 404 * 405 * @param qstate: the state to find mesh state, and that wants to receive 406 * the results from the new subquery. 407 * @param qinfo: what to query for (copied). 408 * @param qflags: what flags to use (RD / CD flag or not). 409 * @param prime: if it is a (stub) priming query. 410 * @param valrec: if it is a validation recursion query (lookup of key, DS). 411 * @param newq: If the new subquery needs initialisation, it is returned, 412 * otherwise NULL is returned. 413 * @param sub: The added mesh state, created if it did not exist already. 414 * @return: false on error, true if success (and init may be needed). 415 */ 416 int (*add_sub)(struct module_qstate* qstate, 417 struct query_info* qinfo, uint16_t qflags, int prime, 418 int valrec, struct module_qstate** newq, 419 struct mesh_state** sub); 420 421 /** 422 * Kill newly attached sub. If attach_sub returns newq for 423 * initialisation, but that fails, then this routine will cleanup and 424 * delete the freshly created sub. 425 * @param newq: the new subquery that is no longer needed. 426 * It is removed. 427 */ 428 void (*kill_sub)(struct module_qstate* newq); 429 430 /** 431 * Detect if adding a dependency for qstate on name,type,class will 432 * create a dependency cycle. 433 * @param qstate: given mesh querystate. 434 * @param qinfo: query info for dependency. 435 * @param flags: query flags of dependency, RD/CD flags. 436 * @param prime: if dependency is a priming query or not. 437 * @param valrec: validation lookup recursion, does not need validation 438 * @return true if the name,type,class exists and the given 439 * qstate mesh exists as a dependency of that name. Thus 440 * if qstate becomes dependent on name,type,class then a 441 * cycle is created. 442 */ 443 int (*detect_cycle)(struct module_qstate* qstate, 444 struct query_info* qinfo, uint16_t flags, int prime, 445 int valrec); 446 447 /** region for temporary usage. May be cleared after operate() call. */ 448 struct regional* scratch; 449 /** buffer for temporary usage. May be cleared after operate() call. */ 450 struct sldns_buffer* scratch_buffer; 451 /** internal data for daemon - worker thread. */ 452 struct worker* worker; 453 /** the worker event base */ 454 struct comm_base* worker_base; 455 /** the outside network */ 456 struct outside_network* outnet; 457 /** mesh area with query state dependencies */ 458 struct mesh_area* mesh; 459 /** allocation service */ 460 struct alloc_cache* alloc; 461 /** random table to generate random numbers */ 462 struct ub_randstate* rnd; 463 /** time in seconds, converted to integer */ 464 time_t* now; 465 /** time in microseconds. Relatively recent. */ 466 struct timeval* now_tv; 467 /** is validation required for messages, controls client-facing 468 * validation status (AD bits) and servfails */ 469 int need_to_validate; 470 /** trusted key storage; these are the configured keys, if not NULL, 471 * otherwise configured by validator. These are the trust anchors, 472 * and are not primed and ready for validation, but on the bright 473 * side, they are read only memory, thus no locks and fast. */ 474 struct val_anchors* anchors; 475 /** negative cache, configured by the validator. if not NULL, 476 * contains NSEC record lookup trees. */ 477 struct val_neg_cache* neg_cache; 478 /** the 5011-probe timer (if any) */ 479 struct comm_timer* probe_timer; 480 /** auth zones */ 481 struct auth_zones* auth_zones; 482 /** Mapping of forwarding zones to targets. 483 * iterator forwarder information. per-thread, created by worker */ 484 struct iter_forwards* fwds; 485 /** 486 * iterator forwarder information. per-thread, created by worker. 487 * The hints -- these aren't stored in the cache because they don't 488 * expire. The hints are always used to "prime" the cache. Note 489 * that both root hints and stub zone "hints" are stored in this 490 * data structure. 491 */ 492 struct iter_hints* hints; 493 /** module specific data. indexed by module id. */ 494 void* modinfo[MAX_MODULE]; 495 496 /* Shared linked list of inplace callback functions */ 497 struct inplace_cb* inplace_cb_lists[inplace_cb_types_total]; 498 499 /** 500 * Shared array of known edns options (size MAX_KNOWN_EDNS_OPTS). 501 * Filled by edns literate modules during init. 502 */ 503 struct edns_known_option* edns_known_options; 504 /* Number of known edns options */ 505 size_t edns_known_options_num; 506 507 /* Make every mesh state unique, do not aggregate mesh states. */ 508 int unique_mesh; 509 }; 510 511 /** 512 * External visible states of the module state machine 513 * Modules may also have an internal state. 514 * Modules are supposed to run to completion or until blocked. 515 */ 516 enum module_ext_state { 517 /** initial state - new query */ 518 module_state_initial = 0, 519 /** waiting for reply to outgoing network query */ 520 module_wait_reply, 521 /** module is waiting for another module */ 522 module_wait_module, 523 /** module is waiting for another module; that other is restarted */ 524 module_restart_next, 525 /** module is waiting for sub-query */ 526 module_wait_subquery, 527 /** module could not finish the query */ 528 module_error, 529 /** module is finished with query */ 530 module_finished 531 }; 532 533 /** 534 * Events that happen to modules, that start or wakeup modules. 535 */ 536 enum module_ev { 537 /** new query */ 538 module_event_new = 0, 539 /** query passed by other module */ 540 module_event_pass, 541 /** reply inbound from server */ 542 module_event_reply, 543 /** no reply, timeout or other error */ 544 module_event_noreply, 545 /** reply is there, but capitalisation check failed */ 546 module_event_capsfail, 547 /** next module is done, and its reply is awaiting you */ 548 module_event_moddone, 549 /** error */ 550 module_event_error 551 }; 552 553 /** 554 * Linked list of sockaddrs 555 * May be allocated such that only 'len' bytes of addr exist for the structure. 556 */ 557 struct sock_list { 558 /** next in list */ 559 struct sock_list* next; 560 /** length of addr */ 561 socklen_t len; 562 /** sockaddr */ 563 struct sockaddr_storage addr; 564 }; 565 566 struct respip_action_info; 567 568 /** 569 * Module state, per query. 570 */ 571 struct module_qstate { 572 /** which query is being answered: name, type, class */ 573 struct query_info qinfo; 574 /** flags uint16 from query */ 575 uint16_t query_flags; 576 /** if this is a (stub or root) priming query (with hints) */ 577 int is_priming; 578 /** if this is a validation recursion query that does not get 579 * validation itself */ 580 int is_valrec; 581 582 /** comm_reply contains server replies */ 583 struct comm_reply* reply; 584 /** the reply message, with message for client and calling module */ 585 struct dns_msg* return_msg; 586 /** the rcode, in case of error, instead of a reply message */ 587 int return_rcode; 588 /** origin of the reply (can be NULL from cache, list for cnames) */ 589 struct sock_list* reply_origin; 590 /** IP blacklist for queries */ 591 struct sock_list* blacklist; 592 /** region for this query. Cleared when query process finishes. */ 593 struct regional* region; 594 /** failure reason information if val-log-level is high */ 595 struct config_strlist* errinf; 596 597 /** which module is executing */ 598 int curmod; 599 /** module states */ 600 enum module_ext_state ext_state[MAX_MODULE]; 601 /** module specific data for query. indexed by module id. */ 602 void* minfo[MAX_MODULE]; 603 /** environment for this query */ 604 struct module_env* env; 605 /** mesh related information for this query */ 606 struct mesh_state* mesh_info; 607 /** how many seconds before expiry is this prefetched (0 if not) */ 608 time_t prefetch_leeway; 609 610 /** incoming edns options from the front end */ 611 struct edns_option* edns_opts_front_in; 612 /** outgoing edns options to the back end */ 613 struct edns_option* edns_opts_back_out; 614 /** incoming edns options from the back end */ 615 struct edns_option* edns_opts_back_in; 616 /** outgoing edns options to the front end */ 617 struct edns_option* edns_opts_front_out; 618 /** whether modules should answer from the cache */ 619 int no_cache_lookup; 620 /** whether modules should store answer in the cache */ 621 int no_cache_store; 622 /** whether to refetch a fresh answer on finishing this state*/ 623 int need_refetch; 624 625 /** 626 * Attributes of clients that share the qstate that may affect IP-based 627 * actions. 628 */ 629 struct respip_client_info* client_info; 630 631 /** Extended result of response-ip action processing, mainly 632 * for logging purposes. */ 633 struct respip_action_info* respip_action_info; 634 635 /** whether the reply should be dropped */ 636 int is_drop; 637 }; 638 639 /** 640 * Module functionality block 641 */ 642 struct module_func_block { 643 /** text string name of module */ 644 const char* name; 645 646 /** 647 * init the module. Called once for the global state. 648 * This is the place to apply settings from the config file. 649 * @param env: module environment. 650 * @param id: module id number. 651 * return: 0 on error 652 */ 653 int (*init)(struct module_env* env, int id); 654 655 /** 656 * de-init, delete, the module. Called once for the global state. 657 * @param env: module environment. 658 * @param id: module id number. 659 */ 660 void (*deinit)(struct module_env* env, int id); 661 662 /** 663 * accept a new query, or work further on existing query. 664 * Changes the qstate->ext_state to be correct on exit. 665 * @param ev: event that causes the module state machine to 666 * (re-)activate. 667 * @param qstate: the query state. 668 * Note that this method is not allowed to change the 669 * query state 'identity', that is query info, qflags, 670 * and priming status. 671 * Attach a subquery to get results to a different query. 672 * @param id: module id number that operate() is called on. 673 * @param outbound: if not NULL this event is due to the reply/timeout 674 * or error on this outbound query. 675 * @return: if at exit the ext_state is: 676 * o wait_module: next module is started. (with pass event). 677 * o error or finished: previous module is resumed. 678 * o otherwise it waits until that event happens (assumes 679 * the service routine to make subrequest or send message 680 * have been called. 681 */ 682 void (*operate)(struct module_qstate* qstate, enum module_ev event, 683 int id, struct outbound_entry* outbound); 684 685 /** 686 * inform super querystate about the results from this subquerystate. 687 * Is called when the querystate is finished. The method invoked is 688 * the one from the current module active in the super querystate. 689 * @param qstate: the query state that is finished. 690 * Examine return_rcode and return_reply in the qstate. 691 * @param id: module id for this module. 692 * This coincides with the current module for the super qstate. 693 * @param super: the super querystate that needs to be informed. 694 */ 695 void (*inform_super)(struct module_qstate* qstate, int id, 696 struct module_qstate* super); 697 698 /** 699 * clear module specific data 700 */ 701 void (*clear)(struct module_qstate* qstate, int id); 702 703 /** 704 * How much memory is the module specific data using. 705 * @param env: module environment. 706 * @param id: the module id. 707 * @return the number of bytes that are alloced. 708 */ 709 size_t (*get_mem)(struct module_env* env, int id); 710 }; 711 712 /** 713 * Debug utility: module external qstate to string 714 * @param s: the state value. 715 * @return descriptive string. 716 */ 717 const char* strextstate(enum module_ext_state s); 718 719 /** 720 * Debug utility: module event to string 721 * @param e: the module event value. 722 * @return descriptive string. 723 */ 724 const char* strmodulevent(enum module_ev e); 725 726 /** 727 * Initialize the edns known options by allocating the required space. 728 * @param env: the module environment. 729 * @return false on failure (no memory). 730 */ 731 int edns_known_options_init(struct module_env* env); 732 733 /** 734 * Free the allocated space for the known edns options. 735 * @param env: the module environment. 736 */ 737 void edns_known_options_delete(struct module_env* env); 738 739 /** 740 * Register a known edns option. Overwrite the flags if it is already 741 * registered. Used before creating workers to register known edns options. 742 * @param opt_code: the edns option code. 743 * @param bypass_cache_stage: whether the option interacts with the cache. 744 * @param no_aggregation: whether the option implies more specific 745 * aggregation. 746 * @param env: the module environment. 747 * @return true on success, false on failure (registering more options than 748 * allowed or trying to register after the environment is copied to the 749 * threads.) 750 */ 751 int edns_register_option(uint16_t opt_code, int bypass_cache_stage, 752 int no_aggregation, struct module_env* env); 753 754 /** 755 * Register an inplace callback function. 756 * @param cb: pointer to the callback function. 757 * @param type: inplace callback type. 758 * @param cbarg: argument for the callback function, or NULL. 759 * @param env: the module environment. 760 * @param id: module id. 761 * @return true on success, false on failure (out of memory or trying to 762 * register after the environment is copied to the threads.) 763 */ 764 int 765 inplace_cb_register(void* cb, enum inplace_cb_list_type type, void* cbarg, 766 struct module_env* env, int id); 767 768 /** 769 * Delete callback for specified type and module id. 770 * @param env: the module environment. 771 * @param type: inplace callback type. 772 * @param id: module id. 773 */ 774 void 775 inplace_cb_delete(struct module_env* env, enum inplace_cb_list_type type, 776 int id); 777 778 /** 779 * Delete all the inplace callback linked lists. 780 * @param env: the module environment. 781 */ 782 void inplace_cb_lists_delete(struct module_env* env); 783 784 /** 785 * Check if an edns option is known. 786 * @param opt_code: the edns option code. 787 * @param env: the module environment. 788 * @return pointer to registered option if the edns option is known, 789 * NULL otherwise. 790 */ 791 struct edns_known_option* edns_option_is_known(uint16_t opt_code, 792 struct module_env* env); 793 794 /** 795 * Check if an edns option needs to bypass the reply from cache stage. 796 * @param list: the edns options. 797 * @param env: the module environment. 798 * @return true if an edns option needs to bypass the cache stage, 799 * false otherwise. 800 */ 801 int edns_bypass_cache_stage(struct edns_option* list, 802 struct module_env* env); 803 804 /** 805 * Check if an unique mesh state is required. Might be triggered by EDNS option 806 * or set for the complete env. 807 * @param list: the edns options. 808 * @param env: the module environment. 809 * @return true if an edns option needs a unique mesh state, 810 * false otherwise. 811 */ 812 int unique_mesh_state(struct edns_option* list, struct module_env* env); 813 814 /** 815 * Log the known edns options. 816 * @param level: the desired verbosity level. 817 * @param env: the module environment. 818 */ 819 void log_edns_known_options(enum verbosity_value level, 820 struct module_env* env); 821 822 #endif /* UTIL_MODULE_H */ 823