Alexandre Lision | 8af73cb | 2013-12-10 14:11:20 -0500 | [diff] [blame] | 1 | /* $Id$ */ |
| 2 | /* |
| 3 | * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| 4 | * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | #include <pjlib-util/dns_server.h> |
| 21 | #include <pjlib-util/errno.h> |
| 22 | #include <pj/activesock.h> |
| 23 | #include <pj/assert.h> |
| 24 | #include <pj/list.h> |
| 25 | #include <pj/log.h> |
| 26 | #include <pj/pool.h> |
| 27 | #include <pj/string.h> |
| 28 | |
| 29 | #define THIS_FILE "dns_server.c" |
| 30 | #define MAX_ANS 16 |
| 31 | #define MAX_PKT 1500 |
| 32 | #define MAX_LABEL 32 |
| 33 | |
| 34 | struct label_tab |
| 35 | { |
| 36 | unsigned count; |
| 37 | |
| 38 | struct { |
| 39 | unsigned pos; |
| 40 | pj_str_t label; |
| 41 | } a[MAX_LABEL]; |
| 42 | }; |
| 43 | |
| 44 | struct rr |
| 45 | { |
| 46 | PJ_DECL_LIST_MEMBER(struct rr); |
| 47 | pj_dns_parsed_rr rec; |
| 48 | }; |
| 49 | |
| 50 | |
| 51 | struct pj_dns_server |
| 52 | { |
| 53 | pj_pool_t *pool; |
| 54 | pj_pool_factory *pf; |
| 55 | pj_activesock_t *asock; |
| 56 | pj_ioqueue_op_key_t send_key; |
| 57 | struct rr rr_list; |
| 58 | }; |
| 59 | |
| 60 | |
| 61 | static pj_bool_t on_data_recvfrom(pj_activesock_t *asock, |
| 62 | void *data, |
| 63 | pj_size_t size, |
| 64 | const pj_sockaddr_t *src_addr, |
| 65 | int addr_len, |
| 66 | pj_status_t status); |
| 67 | |
| 68 | |
| 69 | PJ_DEF(pj_status_t) pj_dns_server_create( pj_pool_factory *pf, |
| 70 | pj_ioqueue_t *ioqueue, |
| 71 | int af, |
| 72 | unsigned port, |
| 73 | unsigned flags, |
| 74 | pj_dns_server **p_srv) |
| 75 | { |
| 76 | pj_pool_t *pool; |
| 77 | pj_dns_server *srv; |
| 78 | pj_sockaddr sock_addr; |
| 79 | pj_activesock_cb sock_cb; |
| 80 | pj_status_t status; |
| 81 | |
| 82 | PJ_ASSERT_RETURN(pf && ioqueue && p_srv && flags==0, PJ_EINVAL); |
| 83 | PJ_ASSERT_RETURN(af==pj_AF_INET() || af==pj_AF_INET6(), PJ_EINVAL); |
| 84 | |
| 85 | pool = pj_pool_create(pf, "dnsserver", 256, 256, NULL); |
| 86 | srv = (pj_dns_server*) PJ_POOL_ZALLOC_T(pool, pj_dns_server); |
| 87 | srv->pool = pool; |
| 88 | srv->pf = pf; |
| 89 | pj_list_init(&srv->rr_list); |
| 90 | |
| 91 | pj_bzero(&sock_addr, sizeof(sock_addr)); |
| 92 | sock_addr.addr.sa_family = (pj_uint16_t)af; |
| 93 | pj_sockaddr_set_port(&sock_addr, (pj_uint16_t)port); |
| 94 | |
| 95 | pj_bzero(&sock_cb, sizeof(sock_cb)); |
| 96 | sock_cb.on_data_recvfrom = &on_data_recvfrom; |
| 97 | |
| 98 | status = pj_activesock_create_udp(pool, &sock_addr, NULL, ioqueue, |
| 99 | &sock_cb, srv, &srv->asock, NULL); |
| 100 | if (status != PJ_SUCCESS) |
| 101 | goto on_error; |
| 102 | |
| 103 | pj_ioqueue_op_key_init(&srv->send_key, sizeof(srv->send_key)); |
| 104 | |
| 105 | status = pj_activesock_start_recvfrom(srv->asock, pool, MAX_PKT, 0); |
| 106 | if (status != PJ_SUCCESS) |
| 107 | goto on_error; |
| 108 | |
| 109 | *p_srv = srv; |
| 110 | return PJ_SUCCESS; |
| 111 | |
| 112 | on_error: |
| 113 | pj_dns_server_destroy(srv); |
| 114 | return status; |
| 115 | } |
| 116 | |
| 117 | |
| 118 | PJ_DEF(pj_status_t) pj_dns_server_destroy(pj_dns_server *srv) |
| 119 | { |
| 120 | PJ_ASSERT_RETURN(srv, PJ_EINVAL); |
| 121 | |
| 122 | if (srv->asock) { |
| 123 | pj_activesock_close(srv->asock); |
| 124 | srv->asock = NULL; |
| 125 | } |
| 126 | |
| 127 | if (srv->pool) { |
| 128 | pj_pool_t *pool = srv->pool; |
| 129 | srv->pool = NULL; |
| 130 | pj_pool_release(pool); |
| 131 | } |
| 132 | |
| 133 | return PJ_SUCCESS; |
| 134 | } |
| 135 | |
| 136 | |
| 137 | static struct rr* find_rr( pj_dns_server *srv, |
| 138 | unsigned dns_class, |
| 139 | unsigned type /* pj_dns_type */, |
| 140 | const pj_str_t *name) |
| 141 | { |
| 142 | struct rr *r; |
| 143 | |
| 144 | r = srv->rr_list.next; |
| 145 | while (r != &srv->rr_list) { |
| 146 | if (r->rec.dnsclass == dns_class && r->rec.type == type && |
| 147 | pj_stricmp(&r->rec.name, name)==0) |
| 148 | { |
| 149 | return r; |
| 150 | } |
| 151 | r = r->next; |
| 152 | } |
| 153 | |
| 154 | return NULL; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | PJ_DEF(pj_status_t) pj_dns_server_add_rec( pj_dns_server *srv, |
| 159 | unsigned count, |
| 160 | const pj_dns_parsed_rr rr_param[]) |
| 161 | { |
| 162 | unsigned i; |
| 163 | |
| 164 | PJ_ASSERT_RETURN(srv && count && rr_param, PJ_EINVAL); |
| 165 | |
| 166 | for (i=0; i<count; ++i) { |
| 167 | struct rr *rr; |
| 168 | |
| 169 | PJ_ASSERT_RETURN(find_rr(srv, rr_param[i].dnsclass, rr_param[i].type, |
| 170 | &rr_param[i].name) == NULL, |
| 171 | PJ_EEXISTS); |
| 172 | |
| 173 | rr = (struct rr*) PJ_POOL_ZALLOC_T(srv->pool, struct rr); |
| 174 | pj_memcpy(&rr->rec, &rr_param[i], sizeof(pj_dns_parsed_rr)); |
| 175 | |
| 176 | pj_list_push_back(&srv->rr_list, rr); |
| 177 | } |
| 178 | |
| 179 | return PJ_SUCCESS; |
| 180 | } |
| 181 | |
| 182 | |
| 183 | PJ_DEF(pj_status_t) pj_dns_server_del_rec( pj_dns_server *srv, |
| 184 | int dns_class, |
| 185 | pj_dns_type type, |
| 186 | const pj_str_t *name) |
| 187 | { |
| 188 | struct rr *rr; |
| 189 | |
| 190 | PJ_ASSERT_RETURN(srv && type && name, PJ_EINVAL); |
| 191 | |
| 192 | rr = find_rr(srv, dns_class, type, name); |
| 193 | if (!rr) |
| 194 | return PJ_ENOTFOUND; |
| 195 | |
| 196 | pj_list_erase(rr); |
| 197 | |
| 198 | return PJ_SUCCESS; |
| 199 | } |
| 200 | |
| 201 | |
| 202 | static void write16(pj_uint8_t *p, pj_uint16_t val) |
| 203 | { |
| 204 | p[0] = (pj_uint8_t)(val >> 8); |
| 205 | p[1] = (pj_uint8_t)(val & 0xFF); |
| 206 | } |
| 207 | |
| 208 | static void write32(pj_uint8_t *p, pj_uint32_t val) |
| 209 | { |
| 210 | val = pj_htonl(val); |
| 211 | pj_memcpy(p, &val, 4); |
| 212 | } |
| 213 | |
| 214 | static int print_name(pj_uint8_t *pkt, int size, |
| 215 | pj_uint8_t *pos, const pj_str_t *name, |
| 216 | struct label_tab *tab) |
| 217 | { |
| 218 | pj_uint8_t *p = pos; |
| 219 | const char *endlabel, *endname; |
| 220 | unsigned i; |
| 221 | pj_str_t label; |
| 222 | |
| 223 | /* Check if name is in the table */ |
| 224 | for (i=0; i<tab->count; ++i) { |
| 225 | if (pj_strcmp(&tab->a[i].label, name)==0) |
| 226 | break; |
| 227 | } |
| 228 | |
| 229 | if (i != tab->count) { |
| 230 | write16(p, (pj_uint16_t)(tab->a[i].pos | (0xc0 << 8))); |
| 231 | return 2; |
| 232 | } else { |
| 233 | if (tab->count < MAX_LABEL) { |
| 234 | tab->a[tab->count].pos = (unsigned)(p-pkt); |
| 235 | tab->a[tab->count].label.ptr = (char*)(p+1); |
| 236 | tab->a[tab->count].label.slen = name->slen; |
| 237 | ++tab->count; |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | endlabel = name->ptr; |
| 242 | endname = name->ptr + name->slen; |
| 243 | |
| 244 | label.ptr = (char*)name->ptr; |
| 245 | |
| 246 | while (endlabel != endname) { |
| 247 | |
| 248 | while (endlabel != endname && *endlabel != '.') |
| 249 | ++endlabel; |
| 250 | |
| 251 | label.slen = (endlabel - label.ptr); |
| 252 | |
| 253 | if (size < label.slen+1) |
| 254 | return -1; |
| 255 | |
| 256 | *p = (pj_uint8_t)label.slen; |
| 257 | pj_memcpy(p+1, label.ptr, label.slen); |
| 258 | |
| 259 | size -= (int)(label.slen+1); |
| 260 | p += (label.slen+1); |
| 261 | |
| 262 | if (endlabel != endname && *endlabel == '.') |
| 263 | ++endlabel; |
| 264 | label.ptr = (char*)endlabel; |
| 265 | } |
| 266 | |
| 267 | if (size == 0) |
| 268 | return -1; |
| 269 | |
| 270 | *p++ = '\0'; |
| 271 | |
| 272 | return (int)(p-pos); |
| 273 | } |
| 274 | |
| 275 | static int print_rr(pj_uint8_t *pkt, int size, pj_uint8_t *pos, |
| 276 | const pj_dns_parsed_rr *rr, struct label_tab *tab) |
| 277 | { |
| 278 | pj_uint8_t *p = pos; |
| 279 | int len; |
| 280 | |
| 281 | len = print_name(pkt, size, pos, &rr->name, tab); |
| 282 | if (len < 0) |
| 283 | return -1; |
| 284 | |
| 285 | p += len; |
| 286 | size -= len; |
| 287 | |
| 288 | if (size < 8) |
| 289 | return -1; |
| 290 | |
| 291 | pj_assert(rr->dnsclass == 1); |
| 292 | |
| 293 | write16(p+0, (pj_uint16_t)rr->type); /* type */ |
| 294 | write16(p+2, (pj_uint16_t)rr->dnsclass); /* class */ |
| 295 | write32(p+4, rr->ttl); /* TTL */ |
| 296 | |
| 297 | p += 8; |
| 298 | size -= 8; |
| 299 | |
| 300 | if (rr->type == PJ_DNS_TYPE_A) { |
| 301 | |
| 302 | if (size < 6) |
| 303 | return -1; |
| 304 | |
| 305 | /* RDLEN is 4 */ |
| 306 | write16(p, 4); |
| 307 | |
| 308 | /* Address */ |
| 309 | pj_memcpy(p+2, &rr->rdata.a.ip_addr, 4); |
| 310 | |
| 311 | p += 6; |
| 312 | size -= 6; |
| 313 | |
| 314 | } else if (rr->type == PJ_DNS_TYPE_CNAME || |
| 315 | rr->type == PJ_DNS_TYPE_NS || |
| 316 | rr->type == PJ_DNS_TYPE_PTR) { |
| 317 | |
| 318 | if (size < 4) |
| 319 | return -1; |
| 320 | |
| 321 | len = print_name(pkt, size-2, p+2, &rr->rdata.cname.name, tab); |
| 322 | if (len < 0) |
| 323 | return -1; |
| 324 | |
| 325 | write16(p, (pj_uint16_t)len); |
| 326 | |
| 327 | p += (len + 2); |
| 328 | size -= (len + 2); |
| 329 | |
| 330 | } else if (rr->type == PJ_DNS_TYPE_SRV) { |
| 331 | |
| 332 | if (size < 10) |
| 333 | return -1; |
| 334 | |
| 335 | write16(p+2, rr->rdata.srv.prio); /* Priority */ |
| 336 | write16(p+4, rr->rdata.srv.weight); /* Weight */ |
| 337 | write16(p+6, rr->rdata.srv.port); /* Port */ |
| 338 | |
| 339 | /* Target */ |
| 340 | len = print_name(pkt, size-8, p+8, &rr->rdata.srv.target, tab); |
| 341 | if (len < 0) |
| 342 | return -1; |
| 343 | |
| 344 | /* RDLEN */ |
| 345 | write16(p, (pj_uint16_t)(len + 6)); |
| 346 | |
| 347 | p += (len + 8); |
| 348 | size -= (len + 8); |
| 349 | |
| 350 | } else { |
| 351 | pj_assert(!"Not supported"); |
| 352 | return -1; |
| 353 | } |
| 354 | |
| 355 | return (int)(p-pos); |
| 356 | } |
| 357 | |
| 358 | static int print_packet(const pj_dns_parsed_packet *rec, pj_uint8_t *pkt, |
| 359 | int size) |
| 360 | { |
| 361 | pj_uint8_t *p = pkt; |
| 362 | struct label_tab tab; |
| 363 | int i, len; |
| 364 | |
| 365 | tab.count = 0; |
| 366 | |
| 367 | pj_assert(sizeof(pj_dns_hdr)==12); |
| 368 | if (size < (int)sizeof(pj_dns_hdr)) |
| 369 | return -1; |
| 370 | |
| 371 | /* Initialize header */ |
| 372 | write16(p+0, rec->hdr.id); |
| 373 | write16(p+2, rec->hdr.flags); |
| 374 | write16(p+4, rec->hdr.qdcount); |
| 375 | write16(p+6, rec->hdr.anscount); |
| 376 | write16(p+8, rec->hdr.nscount); |
| 377 | write16(p+10, rec->hdr.arcount); |
| 378 | |
| 379 | p = pkt + sizeof(pj_dns_hdr); |
| 380 | size -= sizeof(pj_dns_hdr); |
| 381 | |
| 382 | /* Print queries */ |
| 383 | for (i=0; i<rec->hdr.qdcount; ++i) { |
| 384 | |
| 385 | len = print_name(pkt, size, p, &rec->q[i].name, &tab); |
| 386 | if (len < 0) |
| 387 | return -1; |
| 388 | |
| 389 | p += len; |
| 390 | size -= len; |
| 391 | |
| 392 | if (size < 4) |
| 393 | return -1; |
| 394 | |
| 395 | /* Set type */ |
| 396 | write16(p+0, (pj_uint16_t)rec->q[i].type); |
| 397 | |
| 398 | /* Set class (IN=1) */ |
| 399 | pj_assert(rec->q[i].dnsclass == 1); |
| 400 | write16(p+2, rec->q[i].dnsclass); |
| 401 | |
| 402 | p += 4; |
| 403 | } |
| 404 | |
| 405 | /* Print answers */ |
| 406 | for (i=0; i<rec->hdr.anscount; ++i) { |
| 407 | len = print_rr(pkt, size, p, &rec->ans[i], &tab); |
| 408 | if (len < 0) |
| 409 | return -1; |
| 410 | |
| 411 | p += len; |
| 412 | size -= len; |
| 413 | } |
| 414 | |
| 415 | /* Print NS records */ |
| 416 | for (i=0; i<rec->hdr.nscount; ++i) { |
| 417 | len = print_rr(pkt, size, p, &rec->ns[i], &tab); |
| 418 | if (len < 0) |
| 419 | return -1; |
| 420 | |
| 421 | p += len; |
| 422 | size -= len; |
| 423 | } |
| 424 | |
| 425 | /* Print additional records */ |
| 426 | for (i=0; i<rec->hdr.arcount; ++i) { |
| 427 | len = print_rr(pkt, size, p, &rec->arr[i], &tab); |
| 428 | if (len < 0) |
| 429 | return -1; |
| 430 | |
| 431 | p += len; |
| 432 | size -= len; |
| 433 | } |
| 434 | |
| 435 | return (int)(p - pkt); |
| 436 | } |
| 437 | |
| 438 | |
| 439 | static pj_bool_t on_data_recvfrom(pj_activesock_t *asock, |
| 440 | void *data, |
| 441 | pj_size_t size, |
| 442 | const pj_sockaddr_t *src_addr, |
| 443 | int addr_len, |
| 444 | pj_status_t status) |
| 445 | { |
| 446 | pj_dns_server *srv; |
| 447 | pj_pool_t *pool; |
| 448 | pj_dns_parsed_packet *req; |
| 449 | pj_dns_parsed_packet ans; |
| 450 | struct rr *rr; |
| 451 | pj_ssize_t pkt_len; |
| 452 | unsigned i; |
| 453 | |
| 454 | if (status != PJ_SUCCESS) |
| 455 | return PJ_TRUE; |
| 456 | |
| 457 | srv = (pj_dns_server*) pj_activesock_get_user_data(asock); |
| 458 | pool = pj_pool_create(srv->pf, "dnssrvrx", 512, 256, NULL); |
| 459 | |
| 460 | status = pj_dns_parse_packet(pool, data, (unsigned)size, &req); |
| 461 | if (status != PJ_SUCCESS) { |
| 462 | char addrinfo[PJ_INET6_ADDRSTRLEN+10]; |
| 463 | pj_sockaddr_print(src_addr, addrinfo, sizeof(addrinfo), 3); |
| 464 | PJ_LOG(4,(THIS_FILE, "Error parsing query from %s", addrinfo)); |
| 465 | goto on_return; |
| 466 | } |
| 467 | |
| 468 | /* Init answer */ |
| 469 | pj_bzero(&ans, sizeof(ans)); |
| 470 | ans.hdr.id = req->hdr.id; |
| 471 | ans.hdr.qdcount = 1; |
| 472 | ans.q = (pj_dns_parsed_query*) PJ_POOL_ALLOC_T(pool, pj_dns_parsed_query); |
| 473 | pj_memcpy(ans.q, req->q, sizeof(pj_dns_parsed_query)); |
| 474 | |
| 475 | if (req->hdr.qdcount != 1) { |
| 476 | ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_FORMERR); |
| 477 | goto send_pkt; |
| 478 | } |
| 479 | |
| 480 | if (req->q[0].dnsclass != PJ_DNS_CLASS_IN) { |
| 481 | ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NOTIMPL); |
| 482 | goto send_pkt; |
| 483 | } |
| 484 | |
| 485 | /* Find the record */ |
| 486 | rr = find_rr(srv, req->q->dnsclass, req->q->type, &req->q->name); |
| 487 | if (rr == NULL) { |
| 488 | ans.hdr.flags = PJ_DNS_SET_RCODE(PJ_DNS_RCODE_NXDOMAIN); |
| 489 | goto send_pkt; |
| 490 | } |
| 491 | |
| 492 | /* Init answer record */ |
| 493 | ans.hdr.anscount = 0; |
| 494 | ans.ans = (pj_dns_parsed_rr*) |
| 495 | pj_pool_calloc(pool, MAX_ANS, sizeof(pj_dns_parsed_rr)); |
| 496 | |
| 497 | /* DNS SRV query needs special treatment since it returns multiple |
| 498 | * records |
| 499 | */ |
| 500 | if (req->q->type == PJ_DNS_TYPE_SRV) { |
| 501 | struct rr *r; |
| 502 | |
| 503 | r = srv->rr_list.next; |
| 504 | while (r != &srv->rr_list) { |
| 505 | if (r->rec.dnsclass == req->q->dnsclass && |
| 506 | r->rec.type == PJ_DNS_TYPE_SRV && |
| 507 | pj_stricmp(&r->rec.name, &req->q->name)==0 && |
| 508 | ans.hdr.anscount < MAX_ANS) |
| 509 | { |
| 510 | pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec, |
| 511 | sizeof(pj_dns_parsed_rr)); |
| 512 | ++ans.hdr.anscount; |
| 513 | } |
| 514 | r = r->next; |
| 515 | } |
| 516 | } else { |
| 517 | /* Otherwise just copy directly from the server record */ |
| 518 | pj_memcpy(&ans.ans[ans.hdr.anscount], &rr->rec, |
| 519 | sizeof(pj_dns_parsed_rr)); |
| 520 | ++ans.hdr.anscount; |
| 521 | } |
| 522 | |
| 523 | /* For each CNAME entry, add A entry */ |
| 524 | for (i=0; i<ans.hdr.anscount && ans.hdr.anscount < MAX_ANS; ++i) { |
| 525 | if (ans.ans[i].type == PJ_DNS_TYPE_CNAME) { |
| 526 | struct rr *r; |
| 527 | |
| 528 | r = find_rr(srv, ans.ans[i].dnsclass, PJ_DNS_TYPE_A, |
| 529 | &ans.ans[i].name); |
| 530 | pj_memcpy(&ans.ans[ans.hdr.anscount], &r->rec, |
| 531 | sizeof(pj_dns_parsed_rr)); |
| 532 | ++ans.hdr.anscount; |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | send_pkt: |
| 537 | pkt_len = print_packet(&ans, (pj_uint8_t*)data, MAX_PKT); |
| 538 | if (pkt_len < 1) { |
| 539 | PJ_LOG(4,(THIS_FILE, "Error: answer too large")); |
| 540 | goto on_return; |
| 541 | } |
| 542 | |
| 543 | status = pj_activesock_sendto(srv->asock, &srv->send_key, data, &pkt_len, |
| 544 | 0, src_addr, addr_len); |
| 545 | if (status != PJ_SUCCESS && status != PJ_EPENDING) { |
| 546 | PJ_LOG(4,(THIS_FILE, "Error sending answer, status=%d", status)); |
| 547 | goto on_return; |
| 548 | } |
| 549 | |
| 550 | on_return: |
| 551 | pj_pool_release(pool); |
| 552 | return PJ_TRUE; |
| 553 | } |
| 554 | |