1 /* 2 * services/mesh.h - deal with mesh of query states and handle events for that. 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 functions to assist in dealing with a mesh of 40 * query states. This mesh is supposed to be thread-specific. 41 * It consists of query states (per qname, qtype, qclass) and connections 42 * between query states and the super and subquery states, and replies to 43 * send back to clients. 44 */ 45 46 #ifndef SERVICES_MESH_H 47 #define SERVICES_MESH_H 48 49 #include "util/rbtree.h" 50 #include "util/netevent.h" 51 #include "util/data/msgparse.h" 52 #include "util/module.h" 53 #include "services/modstack.h" 54 #include "services/rpz.h" 55 #include "libunbound/unbound.h" 56 struct sldns_buffer; 57 struct mesh_state; 58 struct mesh_reply; 59 struct mesh_cb; 60 struct query_info; 61 struct reply_info; 62 struct outbound_entry; 63 struct timehist; 64 struct respip_client_info; 65 66 /** 67 * Maximum number of mesh state activations. Any more is likely an 68 * infinite loop in the module. It is then terminated. 69 */ 70 #define MESH_MAX_ACTIVATION 10000 71 72 /** 73 * Max number of references-to-references-to-references.. search size. 74 * Any more is treated like 'too large', and the creation of a new 75 * dependency is failed (so that no loops can be created). 76 */ 77 #define MESH_MAX_SUBSUB 1024 78 79 /** 80 * Mesh of query states 81 */ 82 struct mesh_area { 83 /** active module stack */ 84 struct module_stack mods; 85 /** environment for new states */ 86 struct module_env* env; 87 88 /** set of runnable queries (mesh_state.run_node) */ 89 rbtree_type run; 90 /** rbtree of all current queries (mesh_state.node)*/ 91 rbtree_type all; 92 93 /** number of queries for unbound's auth_zones, upstream query */ 94 size_t num_query_authzone_up; 95 /** number of queries for unbound's auth_zones, downstream answers */ 96 size_t num_query_authzone_down; 97 98 /** count of the total number of mesh_reply entries */ 99 size_t num_reply_addrs; 100 /** count of the number of mesh_states that have mesh_replies 101 * Because a state can send results to multiple reply addresses, 102 * this number must be equal or lower than num_reply_addrs. */ 103 size_t num_reply_states; 104 /** number of mesh_states that have no mesh_replies, and also 105 * an empty set of super-states, thus are 'toplevel' or detached 106 * internal opportunistic queries */ 107 size_t num_detached_states; 108 /** number of reply states in the forever list */ 109 size_t num_forever_states; 110 111 /** max total number of reply states to have */ 112 size_t max_reply_states; 113 /** max forever number of reply states to have */ 114 size_t max_forever_states; 115 116 /** stats, cumulative number of reply states jostled out */ 117 size_t stats_jostled; 118 /** stats, cumulative number of incoming client msgs dropped */ 119 size_t stats_dropped; 120 /** stats, number of expired replies sent */ 121 size_t ans_expired; 122 /** stats, number of cached replies from cachedb */ 123 size_t ans_cachedb; 124 /** number of replies sent */ 125 size_t replies_sent; 126 /** sum of waiting times for the replies */ 127 struct timeval replies_sum_wait; 128 /** histogram of time values */ 129 struct timehist* histogram; 130 /** (extended stats) secure replies */ 131 size_t ans_secure; 132 /** (extended stats) bogus replies */ 133 size_t ans_bogus; 134 /** (extended stats) rcodes in replies */ 135 size_t ans_rcode[UB_STATS_RCODE_NUM]; 136 /** (extended stats) rcode nodata in replies */ 137 size_t ans_nodata; 138 /** (extended stats) type of applied RPZ action */ 139 size_t rpz_action[UB_STATS_RPZ_ACTION_NUM]; 140 /** stats, number of queries removed due to discard-timeout */ 141 size_t num_queries_discard_timeout; 142 /** stats, number of queries removed due to wait-limit */ 143 size_t num_queries_wait_limit; 144 /** stats, number of dns error reports generated */ 145 size_t num_dns_error_reports; 146 147 /** backup of query if other operations recurse and need the 148 * network buffers */ 149 struct sldns_buffer* qbuf_bak; 150 151 /** double linked list of the run-to-completion query states. 152 * These are query states with a reply */ 153 struct mesh_state* forever_first; 154 /** last entry in run forever list */ 155 struct mesh_state* forever_last; 156 157 /** double linked list of the query states that can be jostled out 158 * by new queries if too old. These are query states with a reply */ 159 struct mesh_state* jostle_first; 160 /** last entry in jostle list - this is the entry that is newest */ 161 struct mesh_state* jostle_last; 162 /** timeout for jostling. if age is lower, it does not get jostled. */ 163 struct timeval jostle_max; 164 165 /** If we need to use response ip (value passed from daemon)*/ 166 int use_response_ip; 167 /** If we need to use RPZ (value passed from daemon) */ 168 int use_rpz; 169 }; 170 171 /** 172 * A mesh query state 173 * Unique per qname, qtype, qclass (from the qstate). 174 * And RD / CD flag; in case a client turns it off. 175 * And priming queries are different from ordinary queries (because of hints). 176 * 177 * The entire structure is allocated in a region, this region is the qstate 178 * region. All parts (rbtree nodes etc) are also allocated in the region. 179 */ 180 struct mesh_state { 181 /** node in mesh_area all tree, key is this struct. Must be first. */ 182 rbnode_type node; 183 /** node in mesh_area runnable tree, key is this struct */ 184 rbnode_type run_node; 185 /** the query state. Note that the qinfo and query_flags 186 * may not change. */ 187 struct module_qstate s; 188 /** the list of replies to clients for the results */ 189 struct mesh_reply* reply_list; 190 /** the list of callbacks for the results */ 191 struct mesh_cb* cb_list; 192 /** set of superstates (that want this state's result) 193 * contains struct mesh_state_ref* */ 194 rbtree_type super_set; 195 /** set of substates (that this state needs to continue) 196 * contains struct mesh_state_ref* */ 197 rbtree_type sub_set; 198 /** number of activations for the mesh state */ 199 size_t num_activated; 200 201 /** previous in linked list for reply states */ 202 struct mesh_state* prev; 203 /** next in linked list for reply states */ 204 struct mesh_state* next; 205 /** if this state is in the forever list, jostle list, or neither */ 206 enum mesh_list_select { mesh_no_list, mesh_forever_list, 207 mesh_jostle_list } list_select; 208 /** pointer to this state for uniqueness or NULL */ 209 struct mesh_state* unique; 210 211 /** true if replies have been sent out (at end for alignment) */ 212 uint8_t replies_sent; 213 }; 214 215 /** 216 * Rbtree reference to a mesh_state. 217 * Used in super_set and sub_set. 218 */ 219 struct mesh_state_ref { 220 /** node in rbtree for set, key is this structure */ 221 rbnode_type node; 222 /** the mesh state */ 223 struct mesh_state* s; 224 }; 225 226 /** 227 * Reply to a client 228 */ 229 struct mesh_reply { 230 /** next in reply list */ 231 struct mesh_reply* next; 232 /** the query reply destination, packet buffer and where to send. */ 233 struct comm_reply query_reply; 234 /** edns data from query */ 235 struct edns_data edns; 236 /** the time when request was entered */ 237 struct timeval start_time; 238 /** id of query, in network byteorder. */ 239 uint16_t qid; 240 /** flags of query, for reply flags */ 241 uint16_t qflags; 242 /** qname from this query. len same as mesh qinfo. */ 243 uint8_t* qname; 244 /** same as that in query_info. */ 245 struct local_rrset* local_alias; 246 /** send query to this http2 stream, if set */ 247 struct http2_stream* h2_stream; 248 }; 249 250 /** 251 * Mesh result callback func. 252 * called as func(cb_arg, rcode, buffer_with_reply, security, why_bogus, 253 * was_ratelimited); 254 */ 255 typedef void (*mesh_cb_func_type)(void* cb_arg, int rcode, struct sldns_buffer*, 256 enum sec_status, char* why_bogus, int was_ratelimited); 257 258 /** 259 * Callback to result routine 260 */ 261 struct mesh_cb { 262 /** next in list */ 263 struct mesh_cb* next; 264 /** edns data from query */ 265 struct edns_data edns; 266 /** id of query, in network byteorder. */ 267 uint16_t qid; 268 /** flags of query, for reply flags */ 269 uint16_t qflags; 270 /** buffer for reply */ 271 struct sldns_buffer* buf; 272 /** callback routine for results. if rcode != 0 buf has message. 273 * called as cb(cb_arg, rcode, buf, sec_state, why_bogus, was_ratelimited); 274 */ 275 mesh_cb_func_type cb; 276 /** user arg for callback */ 277 void* cb_arg; 278 }; 279 280 /* ------------------- Functions for worker -------------------- */ 281 282 /** 283 * Allocate mesh, to empty. 284 * @param stack: module stack to activate, copied (as readonly reference). 285 * @param env: environment for new queries. 286 * @return mesh: the new mesh or NULL on error. 287 */ 288 struct mesh_area* mesh_create(struct module_stack* stack, 289 struct module_env* env); 290 291 /** 292 * Delete mesh, and all query states and replies in it. 293 * @param mesh: the mesh to delete. 294 */ 295 void mesh_delete(struct mesh_area* mesh); 296 297 /** 298 * New query incoming from clients. Create new query state if needed, and 299 * add mesh_reply to it. Returns error to client on malloc failures. 300 * Will run the mesh area queries to process if a new query state is created. 301 * 302 * @param mesh: the mesh. 303 * @param qinfo: query from client. 304 * @param cinfo: additional information associated with the query client. 305 * 'cinfo' itself is ephemeral but data pointed to by its members 306 * can be assumed to be valid and unchanged until the query processing is 307 * completed. 308 * @param qflags: flags from client query. 309 * @param edns: edns data from client query. 310 * @param rep: where to reply to. 311 * @param qid: query id to reply with. 312 * @param rpz_passthru: if true, the rpz passthru was previously found and 313 * further rpz processing is stopped. 314 */ 315 void mesh_new_client(struct mesh_area* mesh, struct query_info* qinfo, 316 struct respip_client_info* cinfo, uint16_t qflags, 317 struct edns_data* edns, struct comm_reply* rep, uint16_t qid, 318 int rpz_passthru); 319 320 /** 321 * New query with callback. Create new query state if needed, and 322 * add mesh_cb to it. 323 * Will run the mesh area queries to process if a new query state is created. 324 * 325 * @param mesh: the mesh. 326 * @param qinfo: query from client. 327 * @param qflags: flags from client query. 328 * @param edns: edns data from client query. 329 * @param buf: buffer for reply contents. 330 * @param qid: query id to reply with. 331 * @param cb: callback function. 332 * @param cb_arg: callback user arg. 333 * @param rpz_passthru: if true, the rpz passthru was previously found and 334 * further rpz processing is stopped. 335 * @return 0 on error. 336 */ 337 int mesh_new_callback(struct mesh_area* mesh, struct query_info* qinfo, 338 uint16_t qflags, struct edns_data* edns, struct sldns_buffer* buf, 339 uint16_t qid, mesh_cb_func_type cb, void* cb_arg, int rpz_passthru); 340 341 /** 342 * New prefetch message. Create new query state if needed. 343 * Will run the mesh area queries to process if a new query state is created. 344 * 345 * @param mesh: the mesh. 346 * @param qinfo: query from client. 347 * @param qflags: flags from client query. 348 * @param leeway: TTL leeway what to expire earlier for this update. 349 * @param rpz_passthru: if true, the rpz passthru was previously found and 350 * further rpz processing is stopped. 351 * @param addr: sockaddr_storage for the client; to be used with subnet. 352 * @param opt_list: edns opt_list from the client; to be used when subnet is 353 * enabled. 354 */ 355 void mesh_new_prefetch(struct mesh_area* mesh, struct query_info* qinfo, 356 uint16_t qflags, time_t leeway, int rpz_passthru, 357 struct sockaddr_storage* addr, struct edns_option* opt_list); 358 359 /** 360 * Handle new event from the wire. A serviced query has returned. 361 * The query state will be made runnable, and the mesh_area will process 362 * query states until processing is complete. 363 * 364 * @param mesh: the query mesh. 365 * @param e: outbound entry, with query state to run and reply pointer. 366 * @param reply: the comm point reply info. 367 * @param what: NETEVENT_* error code (if not 0, what is wrong, TIMEOUT). 368 */ 369 void mesh_report_reply(struct mesh_area* mesh, struct outbound_entry* e, 370 struct comm_reply* reply, int what); 371 372 /* ------------------- Functions for module environment --------------- */ 373 374 /** 375 * Detach-subqueries. 376 * Remove all sub-query references from this query state. 377 * Keeps super-references of those sub-queries correct. 378 * Updates stat items in mesh_area structure. 379 * @param qstate: used to find mesh state. 380 */ 381 void mesh_detach_subs(struct module_qstate* qstate); 382 383 /** 384 * Attach subquery. 385 * Creates it if it does not exist already. 386 * Keeps sub and super references correct. 387 * Performs a cycle detection - for double check - and fails if there is one. 388 * Also fails if the sub-sub-references become too large. 389 * Updates stat items in mesh_area structure. 390 * Pass if it is priming query or not. 391 * return: 392 * o if error (malloc) happened. 393 * o need to initialise the new state (module init; it is a new state). 394 * so that the next run of the query with this module is successful. 395 * o no init needed, attachment successful. 396 * 397 * @param qstate: the state to find mesh state, and that wants to receive 398 * the results from the new subquery. 399 * @param qinfo: what to query for (copied). 400 * @param qflags: what flags to use (RD / CD flag or not). 401 * @param prime: if it is a (stub) priming query. 402 * @param valrec: if it is a validation recursion query (lookup of key, DS). 403 * @param newq: If the new subquery needs initialisation, it is returned, 404 * otherwise NULL is returned. 405 * @return: false on error, true if success (and init may be needed). 406 */ 407 int mesh_attach_sub(struct module_qstate* qstate, struct query_info* qinfo, 408 uint16_t qflags, int prime, int valrec, struct module_qstate** newq); 409 410 /** 411 * Add detached query. 412 * Creates it if it does not exist already. 413 * Does not make super/sub references. 414 * Performs a cycle detection - for double check - and fails if there is one. 415 * Updates stat items in mesh_area structure. 416 * Pass if it is priming query or not. 417 * return: 418 * o if error (malloc) happened. 419 * o need to initialise the new state (module init; it is a new state). 420 * so that the next run of the query with this module is successful. 421 * o no init needed, attachment successful. 422 * o added subquery, created if it did not exist already. 423 * 424 * @param qstate: the state to find mesh state, and that wants to receive 425 * the results from the new subquery. 426 * @param qinfo: what to query for (copied). 427 * @param qflags: what flags to use (RD / CD flag or not). 428 * @param prime: if it is a (stub) priming query. 429 * @param valrec: if it is a validation recursion query (lookup of key, DS). 430 * @param newq: If the new subquery needs initialisation, it is returned, 431 * otherwise NULL is returned. 432 * @param sub: The added mesh state, created if it did not exist already. 433 * @return: false on error, true if success (and init may be needed). 434 */ 435 int mesh_add_sub(struct module_qstate* qstate, struct query_info* qinfo, 436 uint16_t qflags, int prime, int valrec, struct module_qstate** newq, 437 struct mesh_state** sub); 438 439 /** 440 * Query state is done, send messages to reply entries. 441 * Encode messages using reply entry values and the querystate (with original 442 * qinfo), using given reply_info. 443 * Pass errcode != 0 if an error reply is needed. 444 * If no reply entries, nothing is done. 445 * Must be called before a module can module_finished or return module_error. 446 * The module must handle the super query states itself as well. 447 * 448 * @param mstate: mesh state that is done. return_rcode and return_msg 449 * are used for replies. 450 * return_rcode: if not 0 (NOERROR) an error is sent back (and 451 * return_msg is ignored). 452 * return_msg: reply to encode and send back to clients. 453 */ 454 void mesh_query_done(struct mesh_state* mstate); 455 456 /** 457 * Call inform_super for the super query states that are interested in the 458 * results from this query state. These can then be changed for error 459 * or results. 460 * Called when a module is module_finished or returns module_error. 461 * The super query states become runnable with event module_event_pass, 462 * it calls the current module for the super with the inform_super event. 463 * 464 * @param mesh: mesh area to add newly runnable modules to. 465 * @param mstate: the state that has results, used to find mesh state. 466 */ 467 void mesh_walk_supers(struct mesh_area* mesh, struct mesh_state* mstate); 468 469 /** 470 * Delete mesh state, cleanup and also rbtrees and so on. 471 * Will detach from all super/subnodes. 472 * @param qstate: to remove. 473 */ 474 void mesh_state_delete(struct module_qstate* qstate); 475 476 /* ------------------- Functions for mesh -------------------- */ 477 478 /** 479 * Create and initialize a new mesh state and its query state 480 * Does not put the mesh state into rbtrees and so on. 481 * @param env: module environment to set. 482 * @param qinfo: query info that the mesh is for. 483 * @param cinfo: control info for the query client (can be NULL). 484 * @param qflags: flags for query (RD / CD flag). 485 * @param prime: if true, it is a priming query, set is_priming on mesh state. 486 * @param valrec: if true, it is a validation recursion query, and sets 487 * is_valrec on the mesh state. 488 * @return: new mesh state or NULL on allocation error. 489 */ 490 struct mesh_state* mesh_state_create(struct module_env* env, 491 struct query_info* qinfo, struct respip_client_info* cinfo, 492 uint16_t qflags, int prime, int valrec); 493 494 /** 495 * Make a mesh state unique. 496 * A unique mesh state uses it's unique member to point to itself. 497 * @param mstate: mesh state to check. 498 */ 499 void mesh_state_make_unique(struct mesh_state* mstate); 500 501 /** 502 * Cleanup a mesh state and its query state. Does not do rbtree or 503 * reference cleanup. 504 * @param mstate: mesh state to cleanup. Its pointer may no longer be used 505 * afterwards. Cleanup rbtrees before calling this function. 506 */ 507 void mesh_state_cleanup(struct mesh_state* mstate); 508 509 /** 510 * Delete all mesh states from the mesh. 511 * @param mesh: the mesh area to clear 512 */ 513 void mesh_delete_all(struct mesh_area* mesh); 514 515 /** 516 * Find a mesh state in the mesh area. Pass relevant flags. 517 * 518 * @param mesh: the mesh area to look in. 519 * @param cinfo: if non-NULL client specific info that may affect IP-based 520 * actions that apply to the query result. 521 * @param qinfo: what query 522 * @param qflags: if RD / CD bit is set or not. 523 * @param prime: if it is a priming query. 524 * @param valrec: if it is a validation-recursion query. 525 * @return: mesh state or NULL if not found. 526 */ 527 struct mesh_state* mesh_area_find(struct mesh_area* mesh, 528 struct respip_client_info* cinfo, struct query_info* qinfo, 529 uint16_t qflags, int prime, int valrec); 530 531 /** 532 * Setup attachment super/sub relation between super and sub mesh state. 533 * The relation must not be present when calling the function. 534 * Does not update stat items in mesh_area. 535 * @param super: super state. 536 * @param sub: sub state. 537 * @return: 0 on alloc error. 538 */ 539 int mesh_state_attachment(struct mesh_state* super, struct mesh_state* sub); 540 541 /** 542 * Create new reply structure and attach it to a mesh state. 543 * Does not update stat items in mesh area. 544 * @param s: the mesh state. 545 * @param edns: edns data for reply (bufsize). 546 * @param rep: comm point reply info. 547 * @param qid: ID of reply. 548 * @param qflags: original query flags. 549 * @param qinfo: original query info. 550 * @return: 0 on alloc error. 551 */ 552 int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns, 553 struct comm_reply* rep, uint16_t qid, uint16_t qflags, 554 const struct query_info* qinfo); 555 556 /** 557 * Create new callback structure and attach it to a mesh state. 558 * Does not update stat items in mesh area. 559 * @param s: the mesh state. 560 * @param edns: edns data for reply (bufsize). 561 * @param buf: buffer for reply 562 * @param cb: callback to call with results. 563 * @param cb_arg: callback user arg. 564 * @param qid: ID of reply. 565 * @param qflags: original query flags. 566 * @return: 0 on alloc error. 567 */ 568 int mesh_state_add_cb(struct mesh_state* s, struct edns_data* edns, 569 struct sldns_buffer* buf, mesh_cb_func_type cb, void* cb_arg, 570 uint16_t qid, uint16_t qflags); 571 572 /** 573 * Run the mesh. Run all runnable mesh states. Which can create new 574 * runnable mesh states. Until completion. Automatically called by 575 * mesh_report_reply and mesh_new_client as needed. 576 * @param mesh: mesh area. 577 * @param mstate: first mesh state to run. 578 * @param ev: event the mstate. Others get event_pass. 579 * @param e: if a reply, its outbound entry. 580 */ 581 void mesh_run(struct mesh_area* mesh, struct mesh_state* mstate, 582 enum module_ev ev, struct outbound_entry* e); 583 584 /** 585 * Print some stats about the mesh to the log. 586 * @param mesh: the mesh to print it for. 587 * @param str: descriptive string to go with it. 588 */ 589 void mesh_stats(struct mesh_area* mesh, const char* str); 590 591 /** 592 * Clear the stats that the mesh keeps (number of queries serviced) 593 * @param mesh: the mesh 594 */ 595 void mesh_stats_clear(struct mesh_area* mesh); 596 597 /** 598 * Print all the states in the mesh to the log. 599 * @param mesh: the mesh to print all states of. 600 */ 601 void mesh_log_list(struct mesh_area* mesh); 602 603 /** 604 * Calculate memory size in use by mesh and all queries inside it. 605 * @param mesh: the mesh to examine. 606 * @return size in bytes. 607 */ 608 size_t mesh_get_mem(struct mesh_area* mesh); 609 610 /** 611 * Find cycle; see if the given mesh is in the targets sub, or sub-sub, ... 612 * trees. 613 * If the sub-sub structure is too large, it returns 'a cycle'=2. 614 * @param qstate: given mesh querystate. 615 * @param qinfo: query info for dependency. 616 * @param flags: query flags of dependency. 617 * @param prime: if dependency is a priming query or not. 618 * @param valrec: if it is a validation recursion query (lookup of key, DS). 619 * @return true if the name,type,class exists and the given qstate mesh exists 620 * as a dependency of that name. Thus if qstate becomes dependent on 621 * name,type,class then a cycle is created, this is return value 1. 622 * Too large to search is value 2 (also true). 623 */ 624 int mesh_detect_cycle(struct module_qstate* qstate, struct query_info* qinfo, 625 uint16_t flags, int prime, int valrec); 626 627 /** compare two mesh_states */ 628 int mesh_state_compare(const void* ap, const void* bp); 629 630 /** compare two mesh references */ 631 int mesh_state_ref_compare(const void* ap, const void* bp); 632 633 /** 634 * Make space for another recursion state for a reply in the mesh 635 * @param mesh: mesh area 636 * @param qbuf: query buffer to save if recursion is invoked to make space. 637 * This buffer is necessary, because the following sequence in calls 638 * can result in an overwrite of the incoming query: 639 * delete_other_mesh_query - iter_clean - serviced_delete - waiting 640 * udp query is sent - on error callback - callback sends SERVFAIL reply 641 * over the same network channel, and shared UDP buffer is overwritten. 642 * You can pass NULL if there is no buffer that must be backed up. 643 * @return false if no space is available. 644 */ 645 int mesh_make_new_space(struct mesh_area* mesh, struct sldns_buffer* qbuf); 646 647 /** 648 * Insert mesh state into a double linked list. Inserted at end. 649 * @param m: mesh state. 650 * @param fp: pointer to the first-elem-pointer of the list. 651 * @param lp: pointer to the last-elem-pointer of the list. 652 */ 653 void mesh_list_insert(struct mesh_state* m, struct mesh_state** fp, 654 struct mesh_state** lp); 655 656 /** 657 * Remove mesh state from a double linked list. Remove from any position. 658 * @param m: mesh state. 659 * @param fp: pointer to the first-elem-pointer of the list. 660 * @param lp: pointer to the last-elem-pointer of the list. 661 */ 662 void mesh_list_remove(struct mesh_state* m, struct mesh_state** fp, 663 struct mesh_state** lp); 664 665 /** 666 * Remove mesh reply entry from the reply entry list. Searches for 667 * the comm_point pointer. 668 * @param mesh: to update the counters. 669 * @param m: the mesh state. 670 * @param cp: the comm_point to remove from the list. 671 */ 672 void mesh_state_remove_reply(struct mesh_area* mesh, struct mesh_state* m, 673 struct comm_point* cp); 674 675 /** Callback for when the serve expired client timer has run out. Tries to 676 * find an expired answer in the cache and reply that to the client. 677 * @param arg: the argument passed to the callback. 678 */ 679 void mesh_serve_expired_callback(void* arg); 680 681 /** 682 * Try to get a (expired) cached answer. 683 * This needs to behave like the worker's answer_from_cache() in order to have 684 * the same behavior as when replying from cache. 685 * @param qstate: the module qstate. 686 * @param lookup_qinfo: the query info to look for in the cache. 687 * @param is_expired: set if the cached answer is expired. 688 * @return dns_msg if a cached answer was found, otherwise NULL. 689 */ 690 struct dns_msg* 691 mesh_serve_expired_lookup(struct module_qstate* qstate, 692 struct query_info* lookup_qinfo, int* is_expired); 693 694 /** 695 * See if the mesh has space for more queries. You can allocate queries 696 * anyway, but this checks for the allocated space. 697 * @param mesh: mesh area. 698 * @return true if the query list is full. 699 * It checks the number of all queries, not just number of reply states, 700 * that have a client address. So that spawned queries count too, 701 * that were created by the iterator, or other modules. 702 */ 703 int mesh_jostle_exceeded(struct mesh_area* mesh); 704 705 /** 706 * Give the serve expired responses. 707 * @param mstate: mesh state for query that has serve_expired_data. 708 */ 709 void mesh_respond_serve_expired(struct mesh_state* mstate); 710 711 /** 712 * Remove callback from mesh. Removes the callback from the state. 713 * The state itself is left to run. Searches for the pointer values. 714 * 715 * @param mesh: the mesh. 716 * @param qinfo: query from client. 717 * @param qflags: flags from client query. 718 * @param cb: callback function. 719 * @param cb_arg: callback user arg. 720 */ 721 void mesh_remove_callback(struct mesh_area* mesh, struct query_info* qinfo, 722 uint16_t qflags, mesh_cb_func_type cb, void* cb_arg); 723 724 #endif /* SERVICES_MESH_H */ 725