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