unbound/services/mesh.h

   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 struct sldns_buffer;
  55 struct mesh_state;
  56 struct mesh_reply;
  57 struct mesh_cb;
  58 struct query_info;
  59 struct reply_info;
  60 struct outbound_entry;
  61 struct timehist;
  62
  63 /**
  64  * Maximum number of mesh state activations. Any more is likely an
  65  * infinite loop in the module. It is then terminated.
  66  */
  67 #define MESH_MAX_ACTIVATION 3000
  68
  69 /**
  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).
  73  */
  74 #define MESH_MAX_SUBSUB 1024
  75
  76 /**
  77  * Mesh of query states
  78  */
  79 struct mesh_area {
  80         /** active module stack */
  81         struct module_stack mods;
  82         /** environment for new states */
  83         struct module_env* env;
  84
  85         /** set of runnable queries (mesh_state.run_node) */
  86         rbtree_t run;
  87         /** rbtree of all current queries (mesh_state.node)*/
  88         rbtree_t all;
  89
  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;
 102
 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;
 107
 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 */
 113         size_t 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 */
 119         size_t ans_secure;
 120         /** (extended stats) bogus replies */
 121         size_t ans_bogus;
 122         /** (extended stats) rcodes in replies */
 123         size_t ans_rcode[16];
 124         /** (extended stats) rcode nodata in replies */
 125         size_t ans_nodata;
 126
 127         /** backup of query if other operations recurse and need the
 128          * network buffers */
 129         struct sldns_buffer* qbuf_bak;
 130
 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;
 136
 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;
 144 };
 145
 146 /**
 147  * A mesh query state
 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).
 151  *
 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.
 154  */
 155 struct mesh_state {
 156         /** node in mesh_area all tree, key is this struct. Must be first. */
 157         rbnode_t node;
 158         /** node in mesh_area runnable tree, key is this struct */
 159         rbnode_t run_node;
 160         /** the query state. Note that the qinfo and query_flags
 161          * may not change. */
 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* */
 169         rbtree_t super_set;
 170         /** set of substates (that this state needs to continue)
 171          * contains struct mesh_state_ref* */
 172         rbtree_t sub_set;
 173         /** number of activations for the mesh state */
 174         size_t num_activated;
 175
 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
 184         /** true if replies have been sent out (at end for alignment) */
 185         uint8_t replies_sent;
 186 };
 187
 188 /**
 189  * Rbtree reference to a mesh_state.
 190  * Used in super_set and sub_set.
 191  */
 192 struct mesh_state_ref {
 193         /** node in rbtree for set, key is this structure */
 194         rbnode_t node;
 195         /** the mesh state */
 196         struct mesh_state* s;
 197 };
 198
 199 /**
 200  * Reply to a client
 201  */
 202 struct mesh_reply {
 203         /** next in reply list */
 204         struct mesh_reply* next;
 205         /** the query reply destination, packet buffer and where to send. */
 206         struct comm_reply query_reply;
 207         /** edns data from query */
 208         struct edns_data edns;
 209         /** the time when request was entered */
 210         struct timeval start_time;
 211         /** id of query, in network byteorder. */
 212         uint16_t qid;
 213         /** flags of query, for reply flags */
 214         uint16_t qflags;
 215         /** qname from this query. len same as mesh qinfo. */
 216         uint8_t* qname;
 217 };
 218
 219 /**
 220  * Mesh result callback func.
 221  * called as func(cb_arg, rcode, buffer_with_reply, security, why_bogus);
 222  */
 223 typedef void (*mesh_cb_func_t)(void*, int, struct sldns_buffer*, enum sec_status,
 224         char*);
 225
 226 /**
 227  * Callback to result routine
 228  */
 229 struct mesh_cb {
 230         /** next in list */
 231         struct mesh_cb* next;
 232         /** edns data from query */
 233         struct edns_data edns;
 234         /** id of query, in network byteorder. */
 235         uint16_t qid;
 236         /** flags of query, for reply flags */
 237         uint16_t qflags;
 238         /** buffer for reply */
 239         struct sldns_buffer* buf;
 240
 241         /** callback routine for results. if rcode != 0 buf has message.
 242          * called as cb(cb_arg, rcode, buf, sec_state);
 243          */
 244         mesh_cb_func_t cb;
 245         /** user arg for callback */
 246         void* cb_arg;
 247 };
 248
 249 /* ------------------- Functions for worker -------------------- */
 250
 251 /**
 252  * Allocate mesh, to empty.
 253  * @param stack: module stack to activate, copied (as readonly reference).
 254  * @param env: environment for new queries.
 255  * @return mesh: the new mesh or NULL on error.
 256  */
 257 struct mesh_area* mesh_create(struct module_stack* stack,
 258         struct module_env* env);
 259
 260 /**
 261  * Delete mesh, and all query states and replies in it.
 262  * @param mesh: the mesh to delete.
 263  */
 264 void mesh_delete(struct mesh_area* mesh);
 265
 266 /**
 267  * New query incoming from clients. Create new query state if needed, and
 268  * add mesh_reply to it. Returns error to client on malloc failures.
 269  * Will run the mesh area queries to process if a new query state is created.
 270  *
 271  * @param mesh: the mesh.
 272  * @param qinfo: query from client.
 273  * @param qflags: flags from client query.
 274  * @param edns: edns data from client query.
 275  * @param rep: where to reply to.
 276  * @param qid: query id to reply with.
 277  */
 278 void mesh_new_client(struct mesh_area* mesh, struct query_info* qinfo,
 279         uint16_t qflags, struct edns_data* edns, struct comm_reply* rep,
 280         uint16_t qid);
 281
 282 /**
 283  * New query with callback. Create new query state if needed, and
 284  * add mesh_cb to it.
 285  * Will run the mesh area queries to process if a new query state is created.
 286  *
 287  * @param mesh: the mesh.
 288  * @param qinfo: query from client.
 289  * @param qflags: flags from client query.
 290  * @param edns: edns data from client query.
 291  * @param buf: buffer for reply contents.
 292  * @param qid: query id to reply with.
 293  * @param cb: callback function.
 294  * @param cb_arg: callback user arg.
 295  * @return 0 on error.
 296  */
 297 int mesh_new_callback(struct mesh_area* mesh, struct query_info* qinfo,
 298         uint16_t qflags, struct edns_data* edns, struct sldns_buffer* buf,
 299         uint16_t qid, mesh_cb_func_t cb, void* cb_arg);
 300
 301 /**
 302  * New prefetch message. Create new query state if needed.
 303  * Will run the mesh area queries to process if a new query state is created.
 304  *
 305  * @param mesh: the mesh.
 306  * @param qinfo: query from client.
 307  * @param qflags: flags from client query.
 308  * @param leeway: TTL leeway what to expire earlier for this update.
 309  */
 310 void mesh_new_prefetch(struct mesh_area* mesh, struct query_info* qinfo,
 311         uint16_t qflags, time_t leeway);
 312
 313 /**
 314  * Handle new event from the wire. A serviced query has returned.
 315  * The query state will be made runnable, and the mesh_area will process
 316  * query states until processing is complete.
 317  *
 318  * @param mesh: the query mesh.
 319  * @param e: outbound entry, with query state to run and reply pointer.
 320  * @param reply: the comm point reply info.
 321  * @param what: NETEVENT_* error code (if not 0, what is wrong, TIMEOUT).
 322  */
 323 void mesh_report_reply(struct mesh_area* mesh, struct outbound_entry* e,
 324         struct comm_reply* reply, int what);
 325
 326 /* ------------------- Functions for module environment --------------- */
 327
 328 /**
 329  * Detach-subqueries.
 330  * Remove all sub-query references from this query state.
 331  * Keeps super-references of those sub-queries correct.
 332  * Updates stat items in mesh_area structure.
 333  * @param qstate: used to find mesh state.
 334  */
 335 void mesh_detach_subs(struct module_qstate* qstate);
 336
 337 /**
 338  * Attach subquery.
 339  * Creates it if it does not exist already.
 340  * Keeps sub and super references correct.
 341  * Performs a cycle detection - for double check - and fails if there is one.
 342  * Also fails if the sub-sub-references become too large.
 343  * Updates stat items in mesh_area structure.
 344  * Pass if it is priming query or not.
 345  * return:
 346  *      o if error (malloc) happened.
 347  *      o need to initialise the new state (module init; it is a new state).
 348  *        so that the next run of the query with this module is successful.
 349  *      o no init needed, attachment successful.
 350  *
 351  * @param qstate: the state to find mesh state, and that wants to receive
 352  *      the results from the new subquery.
 353  * @param qinfo: what to query for (copied).
 354  * @param qflags: what flags to use (RD / CD flag or not).
 355  * @param prime: if it is a (stub) priming query.
 356  * @param valrec: if it is a validation recursion query (lookup of key, DS).
 357  * @param newq: If the new subquery needs initialisation, it is returned,
 358  *      otherwise NULL is returned.
 359  * @return: false on error, true if success (and init may be needed).
 360  */
 361 int mesh_attach_sub(struct module_qstate* qstate, struct query_info* qinfo,
 362         uint16_t qflags, int prime, int valrec, struct module_qstate** newq);
 363
 364 /**
 365  * Query state is done, send messages to reply entries.
 366  * Encode messages using reply entry values and the querystate (with original
 367  * qinfo), using given reply_info.
 368  * Pass errcode != 0 if an error reply is needed.
 369  * If no reply entries, nothing is done.
 370  * Must be called before a module can module_finished or return module_error.
 371  * The module must handle the super query states itself as well.
 372  *
 373  * @param mstate: mesh state that is done. return_rcode and return_msg
 374  *      are used for replies.
 375  *      return_rcode: if not 0 (NOERROR) an error is sent back (and
 376  *              return_msg is ignored).
 377  *      return_msg: reply to encode and send back to clients.
 378  */
 379 void mesh_query_done(struct mesh_state* mstate);
 380
 381 /**
 382  * Call inform_super for the super query states that are interested in the
 383  * results from this query state. These can then be changed for error
 384  * or results.
 385  * Called when a module is module_finished or returns module_error.
 386  * The super query states become runnable with event module_event_pass,
 387  * it calls the current module for the super with the inform_super event.
 388  *
 389  * @param mesh: mesh area to add newly runnable modules to.
 390  * @param mstate: the state that has results, used to find mesh state.
 391  */
 392 void mesh_walk_supers(struct mesh_area* mesh, struct mesh_state* mstate);
 393
 394 /**
 395  * Delete mesh state, cleanup and also rbtrees and so on.
 396  * Will detach from all super/subnodes.
 397  * @param qstate: to remove.
 398  */
 399 void mesh_state_delete(struct module_qstate* qstate);
 400
 401 /* ------------------- Functions for mesh -------------------- */
 402
 403 /**
 404  * Create and initialize a new mesh state and its query state
 405  * Does not put the mesh state into rbtrees and so on.
 406  * @param env: module environment to set.
 407  * @param qinfo: query info that the mesh is for.
 408  * @param qflags: flags for query (RD / CD flag).
 409  * @param prime: if true, it is a priming query, set is_priming on mesh state.
 410  * @param valrec: if true, it is a validation recursion query, and sets
 411  *      is_valrec on the mesh state.
 412  * @return: new mesh state or NULL on allocation error.
 413  */
 414 struct mesh_state* mesh_state_create(struct module_env* env,
 415         struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
 416
 417 /**
 418  * Cleanup a mesh state and its query state. Does not do rbtree or
 419  * reference cleanup.
 420  * @param mstate: mesh state to cleanup. Its pointer may no longer be used
 421  *      afterwards. Cleanup rbtrees before calling this function.
 422  */
 423 void mesh_state_cleanup(struct mesh_state* mstate);
 424
 425 /**
 426  * Delete all mesh states from the mesh.
 427  * @param mesh: the mesh area to clear
 428  */
 429 void mesh_delete_all(struct mesh_area* mesh);
 430
 431 /**
 432  * Find a mesh state in the mesh area. Pass relevant flags.
 433  *
 434  * @param mesh: the mesh area to look in.
 435  * @param qinfo: what query
 436  * @param qflags: if RD / CD bit is set or not.
 437  * @param prime: if it is a priming query.
 438  * @param valrec: if it is a validation-recursion query.
 439  * @return: mesh state or NULL if not found.
 440  */
 441 struct mesh_state* mesh_area_find(struct mesh_area* mesh,
 442         struct query_info* qinfo, uint16_t qflags, int prime, int valrec);
 443
 444 /**
 445  * Setup attachment super/sub relation between super and sub mesh state.
 446  * The relation must not be present when calling the function.
 447  * Does not update stat items in mesh_area.
 448  * @param super: super state.
 449  * @param sub: sub state.
 450  * @return: 0 on alloc error.
 451  */
 452 int mesh_state_attachment(struct mesh_state* super, struct mesh_state* sub);
 453
 454 /**
 455  * Create new reply structure and attach it to a mesh state.
 456  * Does not update stat items in mesh area.
 457  * @param s: the mesh state.
 458  * @param edns: edns data for reply (bufsize).
 459  * @param rep: comm point reply info.
 460  * @param qid: ID of reply.
 461  * @param qflags: original query flags.
 462  * @param qname: original query name.
 463  * @return: 0 on alloc error.
 464  */
 465 int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns,
 466         struct comm_reply* rep, uint16_t qid, uint16_t qflags, uint8_t* qname);
 467
 468 /**
 469  * Create new callback structure and attach it to a mesh state.
 470  * Does not update stat items in mesh area.
 471  * @param s: the mesh state.
 472  * @param edns: edns data for reply (bufsize).
 473  * @param buf: buffer for reply
 474  * @param cb: callback to call with results.
 475  * @param cb_arg: callback user arg.
 476  * @param qid: ID of reply.
 477  * @param qflags: original query flags.
 478  * @return: 0 on alloc error.
 479  */
 480 int mesh_state_add_cb(struct mesh_state* s, struct edns_data* edns,
 481         struct sldns_buffer* buf, mesh_cb_func_t cb, void* cb_arg, uint16_t qid,
 482         uint16_t qflags);
 483
 484 /**
 485  * Run the mesh. Run all runnable mesh states. Which can create new
 486  * runnable mesh states. Until completion. Automatically called by
 487  * mesh_report_reply and mesh_new_client as needed.
 488  * @param mesh: mesh area.
 489  * @param mstate: first mesh state to run.
 490  * @param ev: event the mstate. Others get event_pass.
 491  * @param e: if a reply, its outbound entry.
 492  */
 493 void mesh_run(struct mesh_area* mesh, struct mesh_state* mstate,
 494         enum module_ev ev, struct outbound_entry* e);
 495
 496 /**
 497  * Print some stats about the mesh to the log.
 498  * @param mesh: the mesh to print it for.
 499  * @param str: descriptive string to go with it.
 500  */
 501 void mesh_stats(struct mesh_area* mesh, const char* str);
 502
 503 /**
 504  * Clear the stats that the mesh keeps (number of queries serviced)
 505  * @param mesh: the mesh
 506  */
 507 void mesh_stats_clear(struct mesh_area* mesh);
 508
 509 /**
 510  * Print all the states in the mesh to the log.
 511  * @param mesh: the mesh to print all states of.
 512  */
 513 void mesh_log_list(struct mesh_area* mesh);
 514
 515 /**
 516  * Calculate memory size in use by mesh and all queries inside it.
 517  * @param mesh: the mesh to examine.
 518  * @return size in bytes.
 519  */
 520 size_t mesh_get_mem(struct mesh_area* mesh);
 521
 522 /**
 523  * Find cycle; see if the given mesh is in the targets sub, or sub-sub, ...
 524  * trees.
 525  * If the sub-sub structure is too large, it returns 'a cycle'=2.
 526  * @param qstate: given mesh querystate.
 527  * @param qinfo: query info for dependency.
 528  * @param flags: query flags of dependency.
 529  * @param prime: if dependency is a priming query or not.
 530  * @param valrec: if it is a validation recursion query (lookup of key, DS).
 531  * @return true if the name,type,class exists and the given qstate mesh exists
 532  *      as a dependency of that name. Thus if qstate becomes dependent on
 533  *      name,type,class then a cycle is created, this is return value 1.
 534  *      Too large to search is value 2 (also true).
 535  */
 536 int mesh_detect_cycle(struct module_qstate* qstate, struct query_info* qinfo,
 537         uint16_t flags, int prime, int valrec);
 538
 539 /** compare two mesh_states */
 540 int mesh_state_compare(const void* ap, const void* bp);
 541
 542 /** compare two mesh references */
 543 int mesh_state_ref_compare(const void* ap, const void* bp);
 544
 545 /**
 546  * Make space for another recursion state for a reply in the mesh
 547  * @param mesh: mesh area
 548  * @param qbuf: query buffer to save if recursion is invoked to make space.
 549  *    This buffer is necessary, because the following sequence in calls
 550  *    can result in an overwrite of the incoming query:
 551  *    delete_other_mesh_query - iter_clean - serviced_delete - waiting
 552  *    udp query is sent - on error callback - callback sends SERVFAIL reply
 553  *    over the same network channel, and shared UDP buffer is overwritten.
 554  *    You can pass NULL if there is no buffer that must be backed up.
 555  * @return false if no space is available.
 556  */
 557 int mesh_make_new_space(struct mesh_area* mesh, struct sldns_buffer* qbuf);
 558
 559 /**
 560  * Insert mesh state into a double linked list.  Inserted at end.
 561  * @param m: mesh state.
 562  * @param fp: pointer to the first-elem-pointer of the list.
 563  * @param lp: pointer to the last-elem-pointer of the list.
 564  */
 565 void mesh_list_insert(struct mesh_state* m, struct mesh_state** fp,
 566         struct mesh_state** lp);
 567
 568 /**
 569  * Remove mesh state from a double linked list.  Remove from any position.
 570  * @param m: mesh state.
 571  * @param fp: pointer to the first-elem-pointer of the list.
 572  * @param lp: pointer to the last-elem-pointer of the list.
 573  */
 574 void mesh_list_remove(struct mesh_state* m, struct mesh_state** fp,
 575         struct mesh_state** lp);
 576
 577 #endif /* SERVICES_MESH_H */