2 * services/mesh.h - deal with mesh of query states and handle events for that.
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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.
46 #ifndef SERVICES_MESH_H
47 #define SERVICES_MESH_H
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"
60 struct outbound_entry;
64 * Maximum number of mesh state activations. Any more is likely an
65 * infinite loop in the module. It is then terminated.
67 #define MESH_MAX_ACTIVATION 3000
70 * Max number of references-to-references-to-references.. search size.
71 * Any more is treated like 'too large', and the creation of a new
72 * dependency is failed (so that no loops can be created).
74 #define MESH_MAX_SUBSUB 1024
77 * Mesh of query states
80 /** active module stack */
81 struct module_stack mods;
82 /** environment for new states */
83 struct module_env* env;
85 /** set of runnable queries (mesh_state.run_node) */
87 /** rbtree of all current queries (mesh_state.node)*/
90 /** count of the total number of mesh_reply entries */
91 size_t num_reply_addrs;
92 /** count of the number of mesh_states that have mesh_replies
93 * Because a state can send results to multiple reply addresses,
94 * this number must be equal or lower than num_reply_addrs. */
95 size_t num_reply_states;
96 /** number of mesh_states that have no mesh_replies, and also
97 * an empty set of super-states, thus are 'toplevel' or detached
98 * internal opportunistic queries */
99 size_t num_detached_states;
100 /** number of reply states in the forever list */
101 size_t num_forever_states;
103 /** max total number of reply states to have */
104 size_t max_reply_states;
105 /** max forever number of reply states to have */
106 size_t max_forever_states;
108 /** stats, cumulative number of reply states jostled out */
109 size_t stats_jostled;
110 /** stats, cumulative number of incoming client msgs dropped */
111 size_t stats_dropped;
112 /** number of replies sent */
114 /** sum of waiting times for the replies */
115 struct timeval replies_sum_wait;
116 /** histogram of time values */
117 struct timehist* histogram;
118 /** (extended stats) secure replies */
120 /** (extended stats) bogus replies */
122 /** (extended stats) rcodes in replies */
123 size_t ans_rcode[16];
124 /** (extended stats) rcode nodata in replies */
127 /** backup of query if other operations recurse and need the
129 struct sldns_buffer* qbuf_bak;
131 /** double linked list of the run-to-completion query states.
132 * These are query states with a reply */
133 struct mesh_state* forever_first;
134 /** last entry in run forever list */
135 struct mesh_state* forever_last;
137 /** double linked list of the query states that can be jostled out
138 * by new queries if too old. These are query states with a reply */
139 struct mesh_state* jostle_first;
140 /** last entry in jostle list - this is the entry that is newest */
141 struct mesh_state* jostle_last;
142 /** timeout for jostling. if age is lower, it does not get jostled. */
143 struct timeval jostle_max;
148 * Unique per qname, qtype, qclass (from the qstate).
149 * And RD / CD flag; in case a client turns it off.
150 * And priming queries are different from ordinary queries (because of hints).
152 * The entire structure is allocated in a region, this region is the qstate
153 * region. All parts (rbtree nodes etc) are also allocated in the region.
156 /** node in mesh_area all tree, key is this struct. Must be first. */
158 /** node in mesh_area runnable tree, key is this struct */
160 /** the query state. Note that the qinfo and query_flags
162 struct module_qstate s;
163 /** the list of replies to clients for the results */
164 struct mesh_reply* reply_list;
165 /** the list of callbacks for the results */
166 struct mesh_cb* cb_list;
167 /** set of superstates (that want this state's result)
168 * contains struct mesh_state_ref* */
170 /** set of substates (that this state needs to continue)
171 * contains struct mesh_state_ref* */
173 /** number of activations for the mesh state */
174 size_t num_activated;
176 /** previous in linked list for reply states */
177 struct mesh_state* prev;
178 /** next in linked list for reply states */
179 struct mesh_state* next;
180 /** if this state is in the forever list, jostle list, or neither */
181 enum mesh_list_select { mesh_no_list, mesh_forever_list,
182 mesh_jostle_list } list_select;
183 /** pointer to this state for uniqueness or NULL */
184 struct mesh_state* unique;
186 /** true if replies have been sent out (at end for alignment) */
187 uint8_t replies_sent;
191 * Rbtree reference to a mesh_state.
192 * Used in super_set and sub_set.
194 struct mesh_state_ref {
195 /** node in rbtree for set, key is this structure */
197 /** the mesh state */
198 struct mesh_state* s;
205 /** next in reply list */
206 struct mesh_reply* next;
207 /** the query reply destination, packet buffer and where to send. */
208 struct comm_reply query_reply;
209 /** edns data from query */
210 struct edns_data edns;
211 /** the time when request was entered */
212 struct timeval start_time;
213 /** id of query, in network byteorder. */
215 /** flags of query, for reply flags */
217 /** qname from this query. len same as mesh qinfo. */
219 /** same as that in query_info. */
220 struct local_rrset* local_alias;
224 * Mesh result callback func.
225 * called as func(cb_arg, rcode, buffer_with_reply, security, why_bogus);
227 typedef void (*mesh_cb_func_t)(void*, int, struct sldns_buffer*, enum sec_status,
231 * Callback to result routine
235 struct mesh_cb* next;
236 /** edns data from query */
237 struct edns_data edns;
238 /** id of query, in network byteorder. */
240 /** flags of query, for reply flags */
242 /** buffer for reply */
243 struct sldns_buffer* buf;
245 /** callback routine for results. if rcode != 0 buf has message.
246 * called as cb(cb_arg, rcode, buf, sec_state);
249 /** user arg for callback */
253 /* ------------------- Functions for worker -------------------- */
256 * Allocate mesh, to empty.
257 * @param stack: module stack to activate, copied (as readonly reference).
258 * @param env: environment for new queries.
259 * @return mesh: the new mesh or NULL on error.
261 struct mesh_area* mesh_create(struct module_stack* stack,
262 struct module_env* env);
265 * Delete mesh, and all query states and replies in it.
266 * @param mesh: the mesh to delete.
268 void mesh_delete(struct mesh_area* mesh);
271 * New query incoming from clients. Create new query state if needed, and
272 * add mesh_reply to it. Returns error to client on malloc failures.
273 * Will run the mesh area queries to process if a new query state is created.
275 * @param mesh: the mesh.
276 * @param qinfo: query from client.
277 * @param qflags: flags from client query.
278 * @param edns: edns data from client query.
279 * @param rep: where to reply to.
280 * @param qid: query id to reply with.
282 void mesh_new_client(struct mesh_area* mesh, struct query_info* qinfo,
283 uint16_t qflags, struct edns_data* edns, struct comm_reply* rep,
287 * New query with callback. Create new query state if needed, and
289 * Will run the mesh area queries to process if a new query state is created.
291 * @param mesh: the mesh.
292 * @param qinfo: query from client.
293 * @param qflags: flags from client query.
294 * @param edns: edns data from client query.
295 * @param buf: buffer for reply contents.
296 * @param qid: query id to reply with.
297 * @param cb: callback function.
298 * @param cb_arg: callback user arg.
299 * @return 0 on error.
301 int mesh_new_callback(struct mesh_area* mesh, struct query_info* qinfo,
302 uint16_t qflags, struct edns_data* edns, struct sldns_buffer* buf,
303 uint16_t qid, mesh_cb_func_t cb, void* cb_arg);
306 * New prefetch message. Create new query state if needed.
307 * Will run the mesh area queries to process if a new query state is created.
309 * @param mesh: the mesh.
310 * @param qinfo: query from client.
311 * @param qflags: flags from client query.
312 * @param leeway: TTL leeway what to expire earlier for this update.
314 void mesh_new_prefetch(struct mesh_area* mesh, struct query_info* qinfo,
315 uint16_t qflags, time_t leeway);
318 * Handle new event from the wire. A serviced query has returned.
319 * The query state will be made runnable, and the mesh_area will process
320 * query states until processing is complete.
322 * @param mesh: the query mesh.
323 * @param e: outbound entry, with query state to run and reply pointer.
324 * @param reply: the comm point reply info.
325 * @param what: NETEVENT_* error code (if not 0, what is wrong, TIMEOUT).
327 void mesh_report_reply(struct mesh_area* mesh, struct outbound_entry* e,
328 struct comm_reply* reply, int what);
330 /* ------------------- Functions for module environment --------------- */
334 * Remove all sub-query references from this query state.
335 * Keeps super-references of those sub-queries correct.
336 * Updates stat items in mesh_area structure.
337 * @param qstate: used to find mesh state.
339 void mesh_detach_subs(struct module_qstate* qstate);
343 * Creates it if it does not exist already.
344 * Keeps sub and super references correct.
345 * Performs a cycle detection - for double check - and fails if there is one.
346 * Also fails if the sub-sub-references become too large.
347 * Updates stat items in mesh_area structure.
348 * Pass if it is priming query or not.
350 * o if error (malloc) happened.
351 * o need to initialise the new state (module init; it is a new state).
352 * so that the next run of the query with this module is successful.
353 * o no init needed, attachment successful.
355 * @param qstate: the state to find mesh state, and that wants to receive
356 * the results from the new subquery.
357 * @param qinfo: what to query for (copied).
358 * @param qflags: what flags to use (RD / CD flag or not).
359 * @param prime: if it is a (stub) priming query.
360 * @param valrec: if it is a validation recursion query (lookup of key, DS).
361 * @param newq: If the new subquery needs initialisation, it is returned,
362 * otherwise NULL is returned.
363 * @return: false on error, true if success (and init may be needed).
365 int mesh_attach_sub(struct module_qstate* qstate, struct query_info* qinfo,
366 uint16_t qflags, int prime, int valrec, struct module_qstate** newq);
369 * Query state is done, send messages to reply entries.
370 * Encode messages using reply entry values and the querystate (with original
371 * qinfo), using given reply_info.
372 * Pass errcode != 0 if an error reply is needed.
373 * If no reply entries, nothing is done.
374 * Must be called before a module can module_finished or return module_error.
375 * The module must handle the super query states itself as well.
377 * @param mstate: mesh state that is done. return_rcode and return_msg
378 * are used for replies.
379 * return_rcode: if not 0 (NOERROR) an error is sent back (and
380 * return_msg is ignored).
381 * return_msg: reply to encode and send back to clients.
383 void mesh_query_done(struct mesh_state* mstate);
386 * Call inform_super for the super query states that are interested in the
387 * results from this query state. These can then be changed for error
389 * Called when a module is module_finished or returns module_error.
390 * The super query states become runnable with event module_event_pass,
391 * it calls the current module for the super with the inform_super event.
393 * @param mesh: mesh area to add newly runnable modules to.
394 * @param mstate: the state that has results, used to find mesh state.
396 void mesh_walk_supers(struct mesh_area* mesh, struct mesh_state* mstate);
399 * Delete mesh state, cleanup and also rbtrees and so on.
400 * Will detach from all super/subnodes.
401 * @param qstate: to remove.
403 void mesh_state_delete(struct module_qstate* qstate);
405 /* ------------------- Functions for mesh -------------------- */
408 * Create and initialize a new mesh state and its query state
409 * Does not put the mesh state into rbtrees and so on.
410 * @param env: module environment to set.
411 * @param qinfo: query info that the mesh is for.
412 * @param qflags: flags for query (RD / CD flag).
413 * @param prime: if true, it is a priming query, set is_priming on mesh state.
414 * @param valrec: if true, it is a validation recursion query, and sets
415 * is_valrec on the mesh state.
416 * @return: new mesh state or NULL on allocation error.
418 struct mesh_state* mesh_state_create(struct module_env* env,
419 struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
422 * Check if the mesh state is unique.
423 * A unique mesh state uses it's unique member to point to itself, else NULL.
424 * @param mstate: mesh state to check.
425 * @return true if the mesh state is unique, false otherwise.
427 int mesh_state_is_unique(struct mesh_state* mstate);
430 * Make a mesh state unique.
431 * A unique mesh state uses it's unique member to point to itself.
432 * @param mstate: mesh state to check.
434 void mesh_state_make_unique(struct mesh_state* mstate);
437 * Cleanup a mesh state and its query state. Does not do rbtree or
439 * @param mstate: mesh state to cleanup. Its pointer may no longer be used
440 * afterwards. Cleanup rbtrees before calling this function.
442 void mesh_state_cleanup(struct mesh_state* mstate);
445 * Delete all mesh states from the mesh.
446 * @param mesh: the mesh area to clear
448 void mesh_delete_all(struct mesh_area* mesh);
451 * Find a mesh state in the mesh area. Pass relevant flags.
453 * @param mesh: the mesh area to look in.
454 * @param qinfo: what query
455 * @param qflags: if RD / CD bit is set or not.
456 * @param prime: if it is a priming query.
457 * @param valrec: if it is a validation-recursion query.
458 * @return: mesh state or NULL if not found.
460 struct mesh_state* mesh_area_find(struct mesh_area* mesh,
461 struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
464 * Setup attachment super/sub relation between super and sub mesh state.
465 * The relation must not be present when calling the function.
466 * Does not update stat items in mesh_area.
467 * @param super: super state.
468 * @param sub: sub state.
469 * @return: 0 on alloc error.
471 int mesh_state_attachment(struct mesh_state* super, struct mesh_state* sub);
474 * Create new reply structure and attach it to a mesh state.
475 * Does not update stat items in mesh area.
476 * @param s: the mesh state.
477 * @param edns: edns data for reply (bufsize).
478 * @param rep: comm point reply info.
479 * @param qid: ID of reply.
480 * @param qflags: original query flags.
481 * @param qinfo: original query info.
482 * @return: 0 on alloc error.
484 int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns,
485 struct comm_reply* rep, uint16_t qid, uint16_t qflags,
486 const struct query_info* qinfo);
489 * Create new callback structure and attach it to a mesh state.
490 * Does not update stat items in mesh area.
491 * @param s: the mesh state.
492 * @param edns: edns data for reply (bufsize).
493 * @param buf: buffer for reply
494 * @param cb: callback to call with results.
495 * @param cb_arg: callback user arg.
496 * @param qid: ID of reply.
497 * @param qflags: original query flags.
498 * @return: 0 on alloc error.
500 int mesh_state_add_cb(struct mesh_state* s, struct edns_data* edns,
501 struct sldns_buffer* buf, mesh_cb_func_t cb, void* cb_arg, uint16_t qid,
505 * Run the mesh. Run all runnable mesh states. Which can create new
506 * runnable mesh states. Until completion. Automatically called by
507 * mesh_report_reply and mesh_new_client as needed.
508 * @param mesh: mesh area.
509 * @param mstate: first mesh state to run.
510 * @param ev: event the mstate. Others get event_pass.
511 * @param e: if a reply, its outbound entry.
513 void mesh_run(struct mesh_area* mesh, struct mesh_state* mstate,
514 enum module_ev ev, struct outbound_entry* e);
517 * Print some stats about the mesh to the log.
518 * @param mesh: the mesh to print it for.
519 * @param str: descriptive string to go with it.
521 void mesh_stats(struct mesh_area* mesh, const char* str);
524 * Clear the stats that the mesh keeps (number of queries serviced)
525 * @param mesh: the mesh
527 void mesh_stats_clear(struct mesh_area* mesh);
530 * Print all the states in the mesh to the log.
531 * @param mesh: the mesh to print all states of.
533 void mesh_log_list(struct mesh_area* mesh);
536 * Calculate memory size in use by mesh and all queries inside it.
537 * @param mesh: the mesh to examine.
538 * @return size in bytes.
540 size_t mesh_get_mem(struct mesh_area* mesh);
543 * Find cycle; see if the given mesh is in the targets sub, or sub-sub, ...
545 * If the sub-sub structure is too large, it returns 'a cycle'=2.
546 * @param qstate: given mesh querystate.
547 * @param qinfo: query info for dependency.
548 * @param flags: query flags of dependency.
549 * @param prime: if dependency is a priming query or not.
550 * @param valrec: if it is a validation recursion query (lookup of key, DS).
551 * @return true if the name,type,class exists and the given qstate mesh exists
552 * as a dependency of that name. Thus if qstate becomes dependent on
553 * name,type,class then a cycle is created, this is return value 1.
554 * Too large to search is value 2 (also true).
556 int mesh_detect_cycle(struct module_qstate* qstate, struct query_info* qinfo,
557 uint16_t flags, int prime, int valrec);
559 /** compare two mesh_states */
560 int mesh_state_compare(const void* ap, const void* bp);
562 /** compare two mesh references */
563 int mesh_state_ref_compare(const void* ap, const void* bp);
566 * Make space for another recursion state for a reply in the mesh
567 * @param mesh: mesh area
568 * @param qbuf: query buffer to save if recursion is invoked to make space.
569 * This buffer is necessary, because the following sequence in calls
570 * can result in an overwrite of the incoming query:
571 * delete_other_mesh_query - iter_clean - serviced_delete - waiting
572 * udp query is sent - on error callback - callback sends SERVFAIL reply
573 * over the same network channel, and shared UDP buffer is overwritten.
574 * You can pass NULL if there is no buffer that must be backed up.
575 * @return false if no space is available.
577 int mesh_make_new_space(struct mesh_area* mesh, struct sldns_buffer* qbuf);
580 * Insert mesh state into a double linked list. Inserted at end.
581 * @param m: mesh state.
582 * @param fp: pointer to the first-elem-pointer of the list.
583 * @param lp: pointer to the last-elem-pointer of the list.
585 void mesh_list_insert(struct mesh_state* m, struct mesh_state** fp,
586 struct mesh_state** lp);
589 * Remove mesh state from a double linked list. Remove from any position.
590 * @param m: mesh state.
591 * @param fp: pointer to the first-elem-pointer of the list.
592 * @param lp: pointer to the last-elem-pointer of the list.
594 void mesh_list_remove(struct mesh_state* m, struct mesh_state** fp,
595 struct mesh_state** lp);
597 #endif /* SERVICES_MESH_H */