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