1 /* 2 * util/module.h - DNS handling module interface 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains the interface for DNS handling modules. 40 */ 41 42 #ifndef UTIL_MODULE_H 43 #define UTIL_MODULE_H 44 #include "util/storage/lruhash.h" 45 #include "util/data/msgreply.h" 46 #include "util/data/msgparse.h" 47 struct alloc_cache; 48 struct rrset_cache; 49 struct key_cache; 50 struct config_file; 51 struct slabhash; 52 struct query_info; 53 struct edns_data; 54 struct regional; 55 struct worker; 56 struct module_qstate; 57 struct ub_randstate; 58 struct mesh_area; 59 struct mesh_state; 60 struct val_anchors; 61 struct val_neg_cache; 62 struct iter_forwards; 63 struct iter_hints; 64 65 /** Maximum number of modules in operation */ 66 #define MAX_MODULE 5 67 68 /** 69 * Module environment. 70 * Services and data provided to the module. 71 */ 72 struct module_env { 73 /* --- data --- */ 74 /** config file with config options */ 75 struct config_file* cfg; 76 /** shared message cache */ 77 struct slabhash* msg_cache; 78 /** shared rrset cache */ 79 struct rrset_cache* rrset_cache; 80 /** shared infrastructure cache (edns, lameness) */ 81 struct infra_cache* infra_cache; 82 /** shared key cache */ 83 struct key_cache* key_cache; 84 85 /* --- services --- */ 86 /** 87 * Send serviced DNS query to server. UDP/TCP and EDNS is handled. 88 * operate() should return with wait_reply. Later on a callback 89 * will cause operate() to be called with event timeout or reply. 90 * The time until a timeout is calculated from roundtrip timing, 91 * several UDP retries are attempted. 92 * @param qname: query name. (host order) 93 * @param qnamelen: length in bytes of qname, including trailing 0. 94 * @param qtype: query type. (host order) 95 * @param qclass: query class. (host order) 96 * @param flags: host order flags word, with opcode and CD bit. 97 * @param dnssec: if set, EDNS record will have bits set. 98 * If EDNS_DO bit is set, DO bit is set in EDNS records. 99 * If BIT_CD is set, CD bit is set in queries with EDNS records. 100 * @param want_dnssec: if set, the validator wants DNSSEC. Without 101 * EDNS, the answer is likely to be useless for this domain. 102 * @param addr: where to. 103 * @param addrlen: length of addr. 104 * @param zone: delegation point name. 105 * @param zonelen: length of zone name. 106 * @param q: wich query state to reactivate upon return. 107 * @return: false on failure (memory or socket related). no query was 108 * sent. Or returns an outbound entry with qsent and qstate set. 109 * This outbound_entry will be used on later module invocations 110 * that involve this query (timeout, error or reply). 111 */ 112 struct outbound_entry* (*send_query)(uint8_t* qname, size_t qnamelen, 113 uint16_t qtype, uint16_t qclass, uint16_t flags, int dnssec, 114 int want_dnssec, struct sockaddr_storage* addr, 115 socklen_t addrlen, uint8_t* zone, size_t zonelen, 116 struct module_qstate* q); 117 118 /** 119 * Detach-subqueries. 120 * Remove all sub-query references from this query state. 121 * Keeps super-references of those sub-queries correct. 122 * Updates stat items in mesh_area structure. 123 * @param qstate: used to find mesh state. 124 */ 125 void (*detach_subs)(struct module_qstate* qstate); 126 127 /** 128 * Attach subquery. 129 * Creates it if it does not exist already. 130 * Keeps sub and super references correct. 131 * Updates stat items in mesh_area structure. 132 * Pass if it is priming query or not. 133 * return: 134 * o if error (malloc) happened. 135 * o need to initialise the new state (module init; it is a new state). 136 * so that the next run of the query with this module is successful. 137 * o no init needed, attachment successful. 138 * 139 * @param qstate: the state to find mesh state, and that wants to 140 * receive the results from the new subquery. 141 * @param qinfo: what to query for (copied). 142 * @param qflags: what flags to use (RD, CD flag or not). 143 * @param prime: if it is a (stub) priming query. 144 * @param newq: If the new subquery needs initialisation, it is 145 * returned, otherwise NULL is returned. 146 * @return: false on error, true if success (and init may be needed). 147 */ 148 int (*attach_sub)(struct module_qstate* qstate, 149 struct query_info* qinfo, uint16_t qflags, int prime, 150 struct module_qstate** newq); 151 152 /** 153 * Kill newly attached sub. If attach_sub returns newq for 154 * initialisation, but that fails, then this routine will cleanup and 155 * delete the fresly created sub. 156 * @param newq: the new subquery that is no longer needed. 157 * It is removed. 158 */ 159 void (*kill_sub)(struct module_qstate* newq); 160 161 /** 162 * Detect if adding a dependency for qstate on name,type,class will 163 * create a dependency cycle. 164 * @param qstate: given mesh querystate. 165 * @param qinfo: query info for dependency. 166 * @param flags: query flags of dependency, RD/CD flags. 167 * @param prime: if dependency is a priming query or not. 168 * @return true if the name,type,class exists and the given 169 * qstate mesh exists as a dependency of that name. Thus 170 * if qstate becomes dependent on name,type,class then a 171 * cycle is created. 172 */ 173 int (*detect_cycle)(struct module_qstate* qstate, 174 struct query_info* qinfo, uint16_t flags, int prime); 175 176 /** region for temporary usage. May be cleared after operate() call. */ 177 struct regional* scratch; 178 /** buffer for temporary usage. May be cleared after operate() call. */ 179 ldns_buffer* scratch_buffer; 180 /** internal data for daemon - worker thread. */ 181 struct worker* worker; 182 /** mesh area with query state dependencies */ 183 struct mesh_area* mesh; 184 /** allocation service */ 185 struct alloc_cache* alloc; 186 /** random table to generate random numbers */ 187 struct ub_randstate* rnd; 188 /** time in seconds, converted to integer */ 189 uint32_t* now; 190 /** time in microseconds. Relatively recent. */ 191 struct timeval* now_tv; 192 /** is validation required for messages, controls client-facing 193 * validation status (AD bits) and servfails */ 194 int need_to_validate; 195 /** trusted key storage; these are the configured keys, if not NULL, 196 * otherwise configured by validator. These are the trust anchors, 197 * and are not primed and ready for validation, but on the bright 198 * side, they are read only memory, thus no locks and fast. */ 199 struct val_anchors* anchors; 200 /** negative cache, configured by the validator. if not NULL, 201 * contains NSEC record lookup trees. */ 202 struct val_neg_cache* neg_cache; 203 /** the 5011-probe timer (if any) */ 204 struct comm_timer* probe_timer; 205 /** Mapping of forwarding zones to targets. 206 * iterator forwarder information. per-thread, created by worker */ 207 struct iter_forwards* fwds; 208 /** 209 * iterator forwarder information. per-thread, created by worker. 210 * The hints -- these aren't stored in the cache because they don't 211 * expire. The hints are always used to "prime" the cache. Note 212 * that both root hints and stub zone "hints" are stored in this 213 * data structure. 214 */ 215 struct iter_hints* hints; 216 /** module specific data. indexed by module id. */ 217 void* modinfo[MAX_MODULE]; 218 }; 219 220 /** 221 * External visible states of the module state machine 222 * Modules may also have an internal state. 223 * Modules are supposed to run to completion or until blocked. 224 */ 225 enum module_ext_state { 226 /** initial state - new query */ 227 module_state_initial = 0, 228 /** waiting for reply to outgoing network query */ 229 module_wait_reply, 230 /** module is waiting for another module */ 231 module_wait_module, 232 /** module is waiting for another module; that other is restarted */ 233 module_restart_next, 234 /** module is waiting for sub-query */ 235 module_wait_subquery, 236 /** module could not finish the query */ 237 module_error, 238 /** module is finished with query */ 239 module_finished 240 }; 241 242 /** 243 * Events that happen to modules, that start or wakeup modules. 244 */ 245 enum module_ev { 246 /** new query */ 247 module_event_new = 0, 248 /** query passed by other module */ 249 module_event_pass, 250 /** reply inbound from server */ 251 module_event_reply, 252 /** no reply, timeout or other error */ 253 module_event_noreply, 254 /** reply is there, but capitalisation check failed */ 255 module_event_capsfail, 256 /** next module is done, and its reply is awaiting you */ 257 module_event_moddone, 258 /** error */ 259 module_event_error 260 }; 261 262 /** 263 * Linked list of sockaddrs 264 * May be allocated such that only 'len' bytes of addr exist for the structure. 265 */ 266 struct sock_list { 267 /** next in list */ 268 struct sock_list* next; 269 /** length of addr */ 270 socklen_t len; 271 /** sockaddr */ 272 struct sockaddr_storage addr; 273 }; 274 275 /** 276 * Module state, per query. 277 */ 278 struct module_qstate { 279 /** which query is being answered: name, type, class */ 280 struct query_info qinfo; 281 /** flags uint16 from query */ 282 uint16_t query_flags; 283 /** if this is a (stub or root) priming query (with hints) */ 284 int is_priming; 285 286 /** comm_reply contains server replies */ 287 struct comm_reply* reply; 288 /** the reply message, with message for client and calling module */ 289 struct dns_msg* return_msg; 290 /** the rcode, in case of error, instead of a reply message */ 291 int return_rcode; 292 /** origin of the reply (can be NULL from cache, list for cnames) */ 293 struct sock_list* reply_origin; 294 /** IP blacklist for queries */ 295 struct sock_list* blacklist; 296 /** region for this query. Cleared when query process finishes. */ 297 struct regional* region; 298 /** failure reason information if val-log-level is high */ 299 struct config_strlist* errinf; 300 301 /** which module is executing */ 302 int curmod; 303 /** module states */ 304 enum module_ext_state ext_state[MAX_MODULE]; 305 /** module specific data for query. indexed by module id. */ 306 void* minfo[MAX_MODULE]; 307 /** environment for this query */ 308 struct module_env* env; 309 /** mesh related information for this query */ 310 struct mesh_state* mesh_info; 311 /** how many seconds before expiry is this prefetched (0 if not) */ 312 uint32_t prefetch_leeway; 313 }; 314 315 /** 316 * Module functionality block 317 */ 318 struct module_func_block { 319 /** text string name of module */ 320 const char* name; 321 322 /** 323 * init the module. Called once for the global state. 324 * This is the place to apply settings from the config file. 325 * @param env: module environment. 326 * @param id: module id number. 327 * return: 0 on error 328 */ 329 int (*init)(struct module_env* env, int id); 330 331 /** 332 * de-init, delete, the module. Called once for the global state. 333 * @param env: module environment. 334 * @param id: module id number. 335 */ 336 void (*deinit)(struct module_env* env, int id); 337 338 /** 339 * accept a new query, or work further on existing query. 340 * Changes the qstate->ext_state to be correct on exit. 341 * @param ev: event that causes the module state machine to 342 * (re-)activate. 343 * @param qstate: the query state. 344 * Note that this method is not allowed to change the 345 * query state 'identity', that is query info, qflags, 346 * and priming status. 347 * Attach a subquery to get results to a different query. 348 * @param id: module id number that operate() is called on. 349 * @param outbound: if not NULL this event is due to the reply/timeout 350 * or error on this outbound query. 351 * @return: if at exit the ext_state is: 352 * o wait_module: next module is started. (with pass event). 353 * o error or finished: previous module is resumed. 354 * o otherwise it waits until that event happens (assumes 355 * the service routine to make subrequest or send message 356 * have been called. 357 */ 358 void (*operate)(struct module_qstate* qstate, enum module_ev event, 359 int id, struct outbound_entry* outbound); 360 361 /** 362 * inform super querystate about the results from this subquerystate. 363 * Is called when the querystate is finished. The method invoked is 364 * the one from the current module active in the super querystate. 365 * @param qstate: the query state that is finished. 366 * Examine return_rcode and return_reply in the qstate. 367 * @param id: module id for this module. 368 * This coincides with the current module for the super qstate. 369 * @param super: the super querystate that needs to be informed. 370 */ 371 void (*inform_super)(struct module_qstate* qstate, int id, 372 struct module_qstate* super); 373 374 /** 375 * clear module specific data 376 */ 377 void (*clear)(struct module_qstate* qstate, int id); 378 379 /** 380 * How much memory is the module specific data using. 381 * @param env: module environment. 382 * @param id: the module id. 383 * @return the number of bytes that are alloced. 384 */ 385 size_t (*get_mem)(struct module_env* env, int id); 386 }; 387 388 /** 389 * Debug utility: module external qstate to string 390 * @param s: the state value. 391 * @return descriptive string. 392 */ 393 const char* strextstate(enum module_ext_state s); 394 395 /** 396 * Debug utility: module event to string 397 * @param e: the module event value. 398 * @return descriptive string. 399 */ 400 const char* strmodulevent(enum module_ev e); 401 402 #endif /* UTIL_MODULE_H */ 403