1 /* $OpenBSD: getaddrinfo_async.c,v 1.2 2012/04/25 20:28:25 eric Exp $ */ 2 /* 3 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 #include <sys/types.h> 18 #include <sys/uio.h> 19 20 #include <arpa/nameser.h> 21 22 #include <err.h> 23 #include <errno.h> 24 #include <stdlib.h> 25 #include <string.h> 26 #include <unistd.h> 27 28 #include "asr.h" 29 #include "asr_private.h" 30 31 struct match { 32 int family; 33 int socktype; 34 int protocol; 35 }; 36 37 static int getaddrinfo_async_run(struct async *, struct async_res *); 38 static int get_port(const char *, const char *, int); 39 static int iter_family(struct async *, int); 40 static int add_sockaddr(struct async *, struct sockaddr *, const char *); 41 42 static const struct match matches[] = { 43 { PF_INET, SOCK_DGRAM, IPPROTO_UDP }, 44 { PF_INET, SOCK_STREAM, IPPROTO_TCP }, 45 { PF_INET, SOCK_RAW, 0 }, 46 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP }, 47 { PF_INET6, SOCK_STREAM, IPPROTO_TCP }, 48 { PF_INET6, SOCK_RAW, 0 }, 49 { -1, 0, 0, }, 50 }; 51 52 #define MATCH_FAMILY(a, b) ((a) == matches[(b)].family || (a) == PF_UNSPEC) 53 #define MATCH_PROTO(a, b) ((a) == matches[(b)].protocol || (a) == 0) 54 /* Do not match SOCK_RAW unless explicitely specified */ 55 #define MATCH_SOCKTYPE(a, b) ((a) == matches[(b)].socktype || ((a) == 0 && \ 56 matches[(b)].socktype != SOCK_RAW)) 57 58 struct async * 59 getaddrinfo_async(const char *hostname, const char *servname, 60 const struct addrinfo *hints, struct asr *asr) 61 { 62 struct asr_ctx *ac; 63 struct async *as; 64 65 ac = asr_use_resolver(asr); 66 if ((as = async_new(ac, ASR_GETADDRINFO)) == NULL) 67 goto abort; /* errno set */ 68 as->as_run = getaddrinfo_async_run; 69 70 if (hostname && (as->as.ai.hostname = strdup(hostname)) == NULL) 71 goto abort; /* errno set */ 72 if (servname && (as->as.ai.servname = strdup(servname)) == NULL) 73 goto abort; /* errno set */ 74 if (hints) 75 memmove(&as->as.ai.hints, hints, sizeof *hints); 76 else { 77 memset(&as->as.ai.hints, 0, sizeof as->as.ai.hints); 78 as->as.ai.hints.ai_family = PF_UNSPEC; 79 } 80 81 asr_ctx_unref(ac); 82 return (as); 83 abort: 84 if (as) 85 async_free(as); 86 asr_ctx_unref(ac); 87 return (NULL); 88 } 89 90 static int 91 getaddrinfo_async_run(struct async *as, struct async_res *ar) 92 { 93 const char *str; 94 struct addrinfo *ai; 95 int i, family, r; 96 char fqdn[MAXDNAME]; 97 union { 98 struct sockaddr sa; 99 struct sockaddr_in sain; 100 struct sockaddr_in6 sain6; 101 } sa; 102 103 next: 104 switch(as->as_state) { 105 106 case ASR_STATE_INIT: 107 108 /* 109 * First, make sure the parameters are valid. 110 */ 111 112 as->as_count = 0; 113 async_set_state(as, ASR_STATE_HALT); 114 ar->ar_errno = 0; 115 ar->ar_h_errno = NETDB_SUCCESS; 116 ar->ar_gai_errno = 0; 117 118 if (as->as.ai.hostname == NULL && 119 as->as.ai.servname == NULL) { 120 ar->ar_h_errno = NO_RECOVERY; 121 ar->ar_gai_errno = EAI_NONAME; 122 break; 123 } 124 125 ai = &as->as.ai.hints; 126 127 if (ai->ai_addrlen || 128 ai->ai_canonname || 129 ai->ai_addr || 130 ai->ai_next) { 131 ar->ar_h_errno = NO_RECOVERY; 132 ar->ar_gai_errno = EAI_BADHINTS; 133 break; 134 } 135 136 if (ai->ai_flags & ~AI_MASK || 137 (ai->ai_flags & AI_CANONNAME && ai->ai_flags & AI_FQDN)) { 138 ar->ar_h_errno = NO_RECOVERY; 139 ar->ar_gai_errno = EAI_BADFLAGS; 140 break; 141 } 142 143 if (ai->ai_family != PF_UNSPEC && 144 ai->ai_family != PF_INET && 145 ai->ai_family != PF_INET6) { 146 ar->ar_h_errno = NO_RECOVERY; 147 ar->ar_gai_errno = EAI_FAMILY; 148 break; 149 } 150 151 if (ai->ai_socktype && 152 ai->ai_socktype != SOCK_DGRAM && 153 ai->ai_socktype != SOCK_STREAM && 154 ai->ai_socktype != SOCK_RAW) { 155 ar->ar_h_errno = NO_RECOVERY; 156 ar->ar_gai_errno = EAI_SOCKTYPE; 157 break; 158 } 159 160 if (ai->ai_protocol && 161 ai->ai_protocol != IPPROTO_UDP && 162 ai->ai_protocol != IPPROTO_TCP) { 163 ar->ar_h_errno = NO_RECOVERY; 164 ar->ar_gai_errno = EAI_PROTOCOL; 165 break; 166 } 167 168 if (ai->ai_socktype == SOCK_RAW && 169 as->as.ai.servname != NULL) { 170 ar->ar_h_errno = NO_RECOVERY; 171 ar->ar_gai_errno = EAI_SERVICE; 172 break; 173 } 174 175 /* Make sure there is at least a valid combination */ 176 for (i = 0; matches[i].family != -1; i++) 177 if (MATCH_FAMILY(ai->ai_family, i) && 178 MATCH_SOCKTYPE(ai->ai_socktype, i) && 179 MATCH_PROTO(ai->ai_protocol, i)) 180 break; 181 if (matches[i].family == -1) { 182 ar->ar_h_errno = NO_RECOVERY; 183 ar->ar_gai_errno = EAI_BADHINTS; 184 break; 185 } 186 187 if (as->as.ai.servname) { 188 as->as.ai.port_udp = get_port(as->as.ai.servname, 189 "udp", as->as.ai.hints.ai_flags & AI_NUMERICSERV); 190 as->as.ai.port_tcp = get_port(as->as.ai.servname, 191 "tcp", as->as.ai.hints.ai_flags & AI_NUMERICSERV); 192 if (as->as.ai.port_tcp < 0 || as->as.ai.port_udp < 0) { 193 ar->ar_h_errno = NO_RECOVERY; 194 ar->ar_gai_errno = EAI_SERVICE; 195 break; 196 } 197 } 198 199 /* If hostname is NULL, use local address */ 200 if (as->as.ai.hostname == NULL) { 201 for(family = iter_family(as, 1); 202 family != -1; 203 family = iter_family(as, 0)) { 204 /* 205 * We could use statically built sockaddrs for 206 * those, rather than parsing over and over. 207 */ 208 if (family == PF_INET) 209 str = (ai->ai_flags & AI_PASSIVE) ? \ 210 "0.0.0.0" : "127.0.0.1"; 211 else /* PF_INET6 */ 212 str = (ai->ai_flags & AI_PASSIVE) ? \ 213 "::" : "::1"; 214 /* This can't fail */ 215 sockaddr_from_str(&sa.sa, family, str); 216 if ((r = add_sockaddr(as, &sa.sa, NULL))) { 217 ar->ar_errno = errno; 218 ar->ar_h_errno = NETDB_INTERNAL; 219 ar->ar_gai_errno = r; 220 async_set_state(as, ASR_STATE_HALT); 221 break; 222 } 223 } 224 if (ar->ar_gai_errno == 0 && as->as_count == 0) { 225 ar->ar_h_errno = NO_DATA; 226 ar->ar_gai_errno = EAI_NODATA; 227 } 228 break; 229 } 230 231 /* Try numeric addresses first */ 232 for(family = iter_family(as, 1); 233 family != -1; 234 family = iter_family(as, 0)) { 235 236 if (sockaddr_from_str(&sa.sa, family, 237 as->as.ai.hostname) == -1) 238 continue; 239 240 if ((r = add_sockaddr(as, &sa.sa, NULL))) { 241 ar->ar_errno = errno; 242 ar->ar_h_errno = NETDB_INTERNAL; 243 ar->ar_gai_errno = r; 244 async_set_state(as, ASR_STATE_HALT); 245 break; 246 } 247 248 async_set_state(as, ASR_STATE_HALT); 249 break; 250 } 251 if (ar->ar_gai_errno || as->as_count) 252 break; 253 254 if (ai->ai_flags & AI_NUMERICHOST) { 255 ar->ar_h_errno = NO_RECOVERY; 256 ar->ar_gai_errno = EAI_FAIL; 257 async_set_state(as, ASR_STATE_HALT); 258 break; 259 } 260 261 /* Starting domain lookup */ 262 async_set_state(as, ASR_STATE_SEARCH_DOMAIN); 263 break; 264 265 case ASR_STATE_SEARCH_DOMAIN: 266 267 r = asr_iter_domain(as, as->as.ai.hostname, fqdn, sizeof(fqdn)); 268 if (r == -1) { 269 async_set_state(as, ASR_STATE_NOT_FOUND); 270 break; 271 } 272 if (r > (int)sizeof(fqdn)) { 273 ar->ar_errno = EINVAL; 274 ar->ar_h_errno = NO_RECOVERY; 275 ar->ar_gai_errno = EAI_OVERFLOW; 276 async_set_state(as, ASR_STATE_HALT); 277 break; 278 } 279 280 /* 281 * Create a subquery to lookup the host addresses. 282 * We use the special hostaddr_async() API, which has the 283 * nice property of honoring the "lookup" and "family" keyword 284 * in the configuration, thus returning the right address 285 * families in the right order, and thus fixing the current 286 * getaddrinfo() feature documented in the BUGS section of 287 * resolver.conf(5). 288 */ 289 as->as.ai.subq = hostaddr_async_ctx(fqdn, 290 as->as.ai.hints.ai_family, as->as.ai.hints.ai_flags, 291 as->as_ctx); 292 if (as->as.ai.subq == NULL) { 293 ar->ar_errno = errno; 294 if (errno == EINVAL) { 295 ar->ar_h_errno = NO_RECOVERY; 296 ar->ar_gai_errno = EAI_FAIL; 297 } else { 298 ar->ar_h_errno = NETDB_INTERNAL; 299 ar->ar_gai_errno = EAI_MEMORY; 300 } 301 async_set_state(as, ASR_STATE_HALT); 302 break; 303 } 304 async_set_state(as, ASR_STATE_LOOKUP_DOMAIN); 305 break; 306 307 case ASR_STATE_LOOKUP_DOMAIN: 308 309 /* Run the subquery */ 310 if ((r = async_run(as->as.ai.subq, ar)) == ASYNC_COND) 311 return (ASYNC_COND); 312 313 /* Got one more address, use it to extend the result list. */ 314 if (r == ASYNC_YIELD) { 315 if ((r = add_sockaddr(as, &ar->ar_sa.sa, 316 ar->ar_cname))) { 317 ar->ar_errno = errno; 318 ar->ar_h_errno = NETDB_INTERNAL; 319 ar->ar_gai_errno = r; 320 async_set_state(as, ASR_STATE_HALT); 321 } 322 if (ar->ar_cname) 323 free(ar->ar_cname); 324 break; 325 } 326 327 /* 328 * The subquery is done. Stop there if we have at least one 329 * answer. 330 */ 331 as->as.ai.subq = NULL; 332 if (ar->ar_count) { 333 async_set_state(as, ASR_STATE_HALT); 334 break; 335 } 336 337 /* 338 * No anwser for this domain, but we might be suggested to 339 * try again later, so remember this. Then search the next 340 * domain. 341 */ 342 if (ar->ar_gai_errno == EAI_AGAIN) 343 as->as.ai.flags |= ASYNC_AGAIN; 344 async_set_state(as, ASR_STATE_SEARCH_DOMAIN); 345 break; 346 347 case ASR_STATE_NOT_FOUND: 348 349 /* 350 * No result found. Maybe we can try again. 351 */ 352 ar->ar_errno = 0; 353 if (as->as.ai.flags & ASYNC_AGAIN) { 354 ar->ar_h_errno = TRY_AGAIN; 355 ar->ar_gai_errno = EAI_AGAIN; 356 } else { 357 ar->ar_h_errno = NO_DATA; 358 ar->ar_gai_errno = EAI_NODATA; 359 } 360 async_set_state(as, ASR_STATE_HALT); 361 break; 362 363 case ASR_STATE_HALT: 364 365 /* Set the results. */ 366 367 if (ar->ar_gai_errno == 0) { 368 ar->ar_count = as->as_count; 369 ar->ar_addrinfo = as->as.ai.aifirst; 370 as->as.ai.aifirst = NULL; 371 } else { 372 ar->ar_count = 0; 373 ar->ar_addrinfo = NULL; 374 } 375 return (ASYNC_DONE); 376 377 default: 378 ar->ar_errno = EOPNOTSUPP; 379 ar->ar_h_errno = NETDB_INTERNAL; 380 ar->ar_gai_errno = EAI_SYSTEM; 381 async_set_state(as, ASR_STATE_HALT); 382 break; 383 } 384 goto next; 385 } 386 387 /* 388 * Retreive the port number for the service name "servname" and 389 * the protocol "proto". 390 */ 391 static int 392 get_port(const char *servname, const char *proto, int numonly) 393 { 394 struct servent se; 395 struct servent_data sed; 396 int port, r; 397 const char* e; 398 399 if (servname == NULL) 400 return (0); 401 402 e = NULL; 403 port = strtonum(servname, 0, USHRT_MAX, &e); 404 if (e == NULL) 405 return (port); 406 if (errno == ERANGE) 407 return (-2); /* invalid */ 408 if (numonly) 409 return (-2); 410 411 memset(&sed, 0, sizeof(sed)); 412 r = getservbyname_r(servname, proto, &se, &sed); 413 port = ntohs(se.s_port); 414 endservent_r(&sed); 415 416 if (r == -1) 417 return (-1); /* not found */ 418 419 return (port); 420 } 421 422 /* 423 * Iterate over the address families that are to be queried. Use the 424 * list on the async context, unless a specific family was given in hints. 425 */ 426 static int 427 iter_family(struct async *as, int first) 428 { 429 if (first) { 430 as->as_family_idx = 0; 431 if (as->as.ai.hints.ai_family != PF_UNSPEC) 432 return as->as.ai.hints.ai_family; 433 return AS_FAMILY(as); 434 } 435 436 if (as->as.ai.hints.ai_family != PF_UNSPEC) 437 return (-1); 438 439 as->as_family_idx++; 440 441 return AS_FAMILY(as); 442 } 443 444 /* 445 * Use the sockaddr at "sa" to extend the result list on the "as" context, 446 * with the specified canonical name "cname". This function adds one 447 * entry per protocol/socktype match. 448 */ 449 static int 450 add_sockaddr(struct async *as, struct sockaddr *sa, const char *cname) 451 { 452 struct addrinfo *ai; 453 int i, port; 454 455 for(i = 0; matches[i].family != -1; i++) { 456 if (matches[i].family != sa->sa_family || 457 !MATCH_SOCKTYPE(as->as.ai.hints.ai_socktype, i) || 458 !MATCH_PROTO(as->as.ai.hints.ai_protocol, i)) 459 continue; 460 461 if (matches[i].protocol == IPPROTO_TCP) 462 port = as->as.ai.port_tcp; 463 else if (matches[i].protocol == IPPROTO_UDP) 464 port = as->as.ai.port_udp; 465 else 466 port = 0; 467 468 ai = calloc(1, sizeof(*ai) + sa->sa_len); 469 if (ai == NULL) 470 return (EAI_MEMORY); 471 ai->ai_family = sa->sa_family; 472 ai->ai_socktype = matches[i].socktype; 473 ai->ai_protocol = matches[i].protocol; 474 ai->ai_addrlen = sa->sa_len; 475 ai->ai_addr = (void*)(ai + 1); 476 if (cname && 477 as->as.ai.hints.ai_flags & (AI_CANONNAME | AI_FQDN)) { 478 if ((ai->ai_canonname = strdup(cname)) == NULL) { 479 free(ai); 480 return (EAI_MEMORY); 481 } 482 } 483 memmove(ai->ai_addr, sa, sa->sa_len); 484 if (sa->sa_family == PF_INET) 485 ((struct sockaddr_in *)ai->ai_addr)->sin_port = 486 htons(port); 487 else if (sa->sa_family == PF_INET6) 488 ((struct sockaddr_in6 *)ai->ai_addr)->sin6_port = 489 htons(port); 490 491 if (as->as.ai.aifirst == NULL) 492 as->as.ai.aifirst = ai; 493 if (as->as.ai.ailast) 494 as->as.ai.ailast->ai_next = ai; 495 as->as.ai.ailast = ai; 496 as->as_count += 1; 497 } 498 499 return (0); 500 } 501