San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 1 | /* dnsmasq is Copyright (c) 2000-2009 Simon Kelley |
| 2 | |
| 3 | This program is free software; you can redistribute it and/or modify |
| 4 | it under the terms of the GNU General Public License as published by |
| 5 | the Free Software Foundation; version 2 dated June, 1991, or |
| 6 | (at your option) version 3 dated 29 June, 2007. |
| 7 | |
| 8 | This program is distributed in the hope that it will be useful, |
| 9 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | GNU General Public License for more details. |
| 12 | |
| 13 | You should have received a copy of the GNU General Public License |
| 14 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 15 | */ |
| 16 | |
| 17 | #include "dnsmasq.h" |
| 18 | |
| 19 | static struct frec *lookup_frec(unsigned short id, unsigned int crc); |
| 20 | static struct frec *lookup_frec_by_sender(unsigned short id, |
| 21 | union mysockaddr *addr, |
| 22 | unsigned int crc); |
| 23 | static unsigned short get_id(int force, unsigned short force_id, unsigned int crc); |
| 24 | static void free_frec(struct frec *f); |
| 25 | static struct randfd *allocate_rfd(int family); |
| 26 | |
| 27 | /* Send a UDP packet with its source address set as "source" |
| 28 | unless nowild is true, when we just send it with the kernel default */ |
| 29 | static void send_from(int fd, int nowild, char *packet, size_t len, |
| 30 | union mysockaddr *to, struct all_addr *source, |
| 31 | unsigned int iface) |
| 32 | { |
| 33 | struct msghdr msg; |
| 34 | struct iovec iov[1]; |
| 35 | union { |
| 36 | struct cmsghdr align; /* this ensures alignment */ |
| 37 | #if defined(HAVE_LINUX_NETWORK) |
| 38 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
| 39 | #elif defined(IP_SENDSRCADDR) |
| 40 | char control[CMSG_SPACE(sizeof(struct in_addr))]; |
| 41 | #endif |
| 42 | #ifdef HAVE_IPV6 |
| 43 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
| 44 | #endif |
| 45 | } control_u; |
| 46 | |
| 47 | iov[0].iov_base = packet; |
| 48 | iov[0].iov_len = len; |
| 49 | |
| 50 | msg.msg_control = NULL; |
| 51 | msg.msg_controllen = 0; |
| 52 | msg.msg_flags = 0; |
| 53 | msg.msg_name = to; |
| 54 | msg.msg_namelen = sa_len(to); |
| 55 | msg.msg_iov = iov; |
| 56 | msg.msg_iovlen = 1; |
| 57 | |
| 58 | if (!nowild) |
| 59 | { |
| 60 | struct cmsghdr *cmptr; |
| 61 | msg.msg_control = &control_u; |
| 62 | msg.msg_controllen = sizeof(control_u); |
| 63 | cmptr = CMSG_FIRSTHDR(&msg); |
| 64 | |
| 65 | if (to->sa.sa_family == AF_INET) |
| 66 | { |
| 67 | #if defined(HAVE_LINUX_NETWORK) |
| 68 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
| 69 | pkt->ipi_ifindex = 0; |
| 70 | pkt->ipi_spec_dst = source->addr.addr4; |
| 71 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); |
| 72 | cmptr->cmsg_level = SOL_IP; |
| 73 | cmptr->cmsg_type = IP_PKTINFO; |
| 74 | #elif defined(IP_SENDSRCADDR) |
| 75 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
| 76 | *a = source->addr.addr4; |
| 77 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); |
| 78 | cmptr->cmsg_level = IPPROTO_IP; |
| 79 | cmptr->cmsg_type = IP_SENDSRCADDR; |
| 80 | #endif |
| 81 | } |
| 82 | else |
| 83 | #ifdef HAVE_IPV6 |
| 84 | { |
| 85 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); |
| 86 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ |
| 87 | pkt->ipi6_addr = source->addr.addr6; |
| 88 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); |
| 89 | cmptr->cmsg_type = IPV6_PKTINFO; |
| 90 | cmptr->cmsg_level = IPV6_LEVEL; |
| 91 | } |
| 92 | #else |
| 93 | iface = 0; /* eliminate warning */ |
| 94 | #endif |
| 95 | } |
| 96 | |
| 97 | retry: |
| 98 | if (sendmsg(fd, &msg, 0) == -1) |
| 99 | { |
| 100 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
| 101 | by returning EINVAL from sendmsg. In that case, try again without setting the |
| 102 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ |
| 103 | if (errno == EINVAL && msg.msg_controllen) |
| 104 | { |
| 105 | msg.msg_controllen = 0; |
| 106 | goto retry; |
| 107 | } |
| 108 | if (retry_send()) |
| 109 | goto retry; |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | static unsigned short search_servers(time_t now, struct all_addr **addrpp, |
| 114 | unsigned short qtype, char *qdomain, int *type, char **domain) |
| 115 | |
| 116 | { |
| 117 | /* If the query ends in the domain in one of our servers, set |
| 118 | domain to point to that name. We find the largest match to allow both |
| 119 | domain.org and sub.domain.org to exist. */ |
| 120 | |
| 121 | unsigned int namelen = strlen(qdomain); |
| 122 | unsigned int matchlen = 0; |
| 123 | struct server *serv; |
| 124 | unsigned short flags = 0; |
| 125 | |
| 126 | for (serv = daemon->servers; serv; serv=serv->next) |
| 127 | /* domain matches take priority over NODOTS matches */ |
| 128 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
| 129 | { |
| 130 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; |
| 131 | *type = SERV_FOR_NODOTS; |
| 132 | if (serv->flags & SERV_NO_ADDR) |
| 133 | flags = F_NXDOMAIN; |
| 134 | else if (serv->flags & SERV_LITERAL_ADDRESS) |
| 135 | { |
| 136 | if (sflag & qtype) |
| 137 | { |
| 138 | flags = sflag; |
| 139 | if (serv->addr.sa.sa_family == AF_INET) |
| 140 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; |
| 141 | #ifdef HAVE_IPV6 |
| 142 | else |
| 143 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; |
| 144 | #endif |
| 145 | } |
| 146 | else if (!flags || (flags & F_NXDOMAIN)) |
| 147 | flags = F_NOERR; |
| 148 | } |
| 149 | } |
| 150 | else if (serv->flags & SERV_HAS_DOMAIN) |
| 151 | { |
| 152 | unsigned int domainlen = strlen(serv->domain); |
| 153 | char *matchstart = qdomain + namelen - domainlen; |
| 154 | if (namelen >= domainlen && |
| 155 | hostname_isequal(matchstart, serv->domain) && |
| 156 | domainlen >= matchlen && |
| 157 | (domainlen == 0 || namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) |
| 158 | { |
| 159 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; |
| 160 | *type = SERV_HAS_DOMAIN; |
| 161 | *domain = serv->domain; |
| 162 | matchlen = domainlen; |
| 163 | if (serv->flags & SERV_NO_ADDR) |
| 164 | flags = F_NXDOMAIN; |
| 165 | else if (serv->flags & SERV_LITERAL_ADDRESS) |
| 166 | { |
| 167 | if (sflag & qtype) |
| 168 | { |
| 169 | flags = sflag; |
| 170 | if (serv->addr.sa.sa_family == AF_INET) |
| 171 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; |
| 172 | #ifdef HAVE_IPV6 |
| 173 | else |
| 174 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; |
| 175 | #endif |
| 176 | } |
| 177 | else if (!flags || (flags & F_NXDOMAIN)) |
| 178 | flags = F_NOERR; |
| 179 | } |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | if (flags == 0 && !(qtype & F_BIGNAME) && |
| 184 | (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
| 185 | /* don't forward simple names, make exception for NS queries and empty name. */ |
| 186 | flags = F_NXDOMAIN; |
| 187 | |
| 188 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now)) |
| 189 | flags = F_NOERR; |
| 190 | |
| 191 | if (flags) |
| 192 | { |
| 193 | int logflags = 0; |
| 194 | |
| 195 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
| 196 | logflags = F_NEG | qtype; |
| 197 | |
| 198 | log_query(logflags | flags | F_CONFIG | F_FORWARD, qdomain, *addrpp, NULL); |
| 199 | } |
| 200 | |
| 201 | return flags; |
| 202 | } |
| 203 | |
| 204 | static int forward_query(int udpfd, union mysockaddr *udpaddr, |
| 205 | struct all_addr *dst_addr, unsigned int dst_iface, |
| 206 | HEADER *header, size_t plen, time_t now, struct frec *forward) |
| 207 | { |
| 208 | char *domain = NULL; |
| 209 | int type = 0; |
| 210 | struct all_addr *addrp = NULL; |
| 211 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
| 212 | unsigned short flags = 0; |
| 213 | unsigned short gotname = extract_request(header, plen, daemon->namebuff, NULL); |
| 214 | struct server *start = NULL; |
| 215 | |
| 216 | /* may be no servers available. */ |
| 217 | if (!daemon->servers) |
| 218 | forward = NULL; |
| 219 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
| 220 | { |
| 221 | /* retry on existing query, send to all available servers */ |
| 222 | domain = forward->sentto->domain; |
| 223 | forward->sentto->failed_queries++; |
| 224 | if (!(daemon->options & OPT_ORDER)) |
| 225 | { |
| 226 | forward->forwardall = 1; |
| 227 | daemon->last_server = NULL; |
| 228 | } |
| 229 | type = forward->sentto->flags & SERV_TYPE; |
| 230 | if (!(start = forward->sentto->next)) |
| 231 | start = daemon->servers; /* at end of list, recycle */ |
| 232 | header->id = htons(forward->new_id); |
| 233 | } |
| 234 | else |
| 235 | { |
| 236 | if (gotname) |
| 237 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain); |
| 238 | |
| 239 | if (!flags && !(forward = get_new_frec(now, NULL))) |
| 240 | /* table full - server failure. */ |
| 241 | flags = F_NEG; |
| 242 | |
| 243 | if (forward) |
| 244 | { |
| 245 | /* force unchanging id for signed packets */ |
| 246 | int is_sign; |
| 247 | find_pseudoheader(header, plen, NULL, NULL, &is_sign); |
| 248 | |
| 249 | forward->source = *udpaddr; |
| 250 | forward->dest = *dst_addr; |
| 251 | forward->iface = dst_iface; |
| 252 | forward->orig_id = ntohs(header->id); |
| 253 | forward->new_id = get_id(is_sign, forward->orig_id, crc); |
| 254 | forward->fd = udpfd; |
| 255 | forward->crc = crc; |
| 256 | forward->forwardall = 0; |
| 257 | header->id = htons(forward->new_id); |
| 258 | |
| 259 | /* In strict_order mode, or when using domain specific servers |
| 260 | always try servers in the order specified in resolv.conf, |
| 261 | otherwise, use the one last known to work. */ |
| 262 | |
| 263 | if (type != 0 || (daemon->options & OPT_ORDER)) |
| 264 | start = daemon->servers; |
| 265 | else if (!(start = daemon->last_server) || |
| 266 | daemon->forwardcount++ > FORWARD_TEST || |
| 267 | difftime(now, daemon->forwardtime) > FORWARD_TIME) |
| 268 | { |
| 269 | start = daemon->servers; |
| 270 | forward->forwardall = 1; |
| 271 | daemon->forwardcount = 0; |
| 272 | daemon->forwardtime = now; |
| 273 | } |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | /* check for send errors here (no route to host) |
| 278 | if we fail to send to all nameservers, send back an error |
| 279 | packet straight away (helps modem users when offline) */ |
| 280 | |
| 281 | if (!flags && forward) |
| 282 | { |
| 283 | struct server *firstsentto = start; |
| 284 | int forwarded = 0; |
| 285 | |
| 286 | while (1) |
| 287 | { |
| 288 | /* only send to servers dealing with our domain. |
| 289 | domain may be NULL, in which case server->domain |
| 290 | must be NULL also. */ |
| 291 | |
| 292 | if (type == (start->flags & SERV_TYPE) && |
| 293 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
| 294 | !(start->flags & SERV_LITERAL_ADDRESS)) |
| 295 | { |
| 296 | int fd; |
| 297 | |
| 298 | /* find server socket to use, may need to get random one. */ |
| 299 | if (start->sfd) |
| 300 | fd = start->sfd->fd; |
| 301 | else |
| 302 | { |
| 303 | #ifdef HAVE_IPV6 |
| 304 | if (start->addr.sa.sa_family == AF_INET6) |
| 305 | { |
| 306 | if (!forward->rfd6 && |
| 307 | !(forward->rfd6 = allocate_rfd(AF_INET6))) |
| 308 | break; |
| 309 | daemon->rfd_save = forward->rfd6; |
| 310 | fd = forward->rfd6->fd; |
| 311 | } |
| 312 | else |
| 313 | #endif |
| 314 | { |
| 315 | if (!forward->rfd4 && |
| 316 | !(forward->rfd4 = allocate_rfd(AF_INET))) |
| 317 | break; |
| 318 | daemon->rfd_save = forward->rfd4; |
| 319 | fd = forward->rfd4->fd; |
| 320 | } |
Lorenzo Colitti | 68eff53 | 2014-08-26 14:06:34 -0700 | [diff] [blame] | 321 | |
| 322 | #ifdef ANDROID |
| 323 | // Mark the socket so it goes out on the correct network. Note |
| 324 | // that we never clear the mark, only re-set it the next time we |
| 325 | // allocate a new random fd. This is because we buffer DNS |
| 326 | // queries (in daemon->srv_save, daemon->packet_len) and socket |
| 327 | // file descriptors (in daemon->rfd_save) with the expectation of |
| 328 | // being able to use them again. |
| 329 | // |
| 330 | // Server fds are marked separately in allocate_sfd. |
| 331 | setsockopt(fd, SOL_SOCKET, SO_MARK, &start->mark, sizeof(start->mark)); |
| 332 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 333 | } |
Lorenzo Colitti | 68eff53 | 2014-08-26 14:06:34 -0700 | [diff] [blame] | 334 | |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 335 | if (sendto(fd, (char *)header, plen, 0, |
| 336 | &start->addr.sa, |
| 337 | sa_len(&start->addr)) == -1) |
| 338 | { |
| 339 | if (retry_send()) |
| 340 | continue; |
| 341 | } |
| 342 | else |
| 343 | { |
| 344 | /* Keep info in case we want to re-send this packet */ |
| 345 | daemon->srv_save = start; |
| 346 | daemon->packet_len = plen; |
| 347 | |
| 348 | if (!gotname) |
| 349 | strcpy(daemon->namebuff, "query"); |
| 350 | if (start->addr.sa.sa_family == AF_INET) |
| 351 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
| 352 | (struct all_addr *)&start->addr.in.sin_addr, NULL); |
| 353 | #ifdef HAVE_IPV6 |
| 354 | else |
| 355 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
| 356 | (struct all_addr *)&start->addr.in6.sin6_addr, NULL); |
| 357 | #endif |
| 358 | start->queries++; |
| 359 | forwarded = 1; |
| 360 | forward->sentto = start; |
| 361 | if (!forward->forwardall) |
| 362 | break; |
| 363 | forward->forwardall++; |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | if (!(start = start->next)) |
| 368 | start = daemon->servers; |
| 369 | |
| 370 | if (start == firstsentto) |
| 371 | break; |
| 372 | } |
| 373 | |
| 374 | if (forwarded) |
| 375 | return 1; |
| 376 | |
| 377 | /* could not send on, prepare to return */ |
| 378 | header->id = htons(forward->orig_id); |
| 379 | free_frec(forward); /* cancel */ |
| 380 | } |
| 381 | |
| 382 | /* could not send on, return empty answer or address if known for whole domain */ |
| 383 | if (udpfd != -1) |
| 384 | { |
| 385 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
| 386 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); |
| 387 | } |
| 388 | |
| 389 | return 0; |
| 390 | } |
| 391 | |
| 392 | static size_t process_reply(HEADER *header, time_t now, |
| 393 | struct server *server, size_t n) |
| 394 | { |
| 395 | unsigned char *pheader, *sizep; |
| 396 | int munged = 0, is_sign; |
| 397 | size_t plen; |
| 398 | |
| 399 | /* If upstream is advertising a larger UDP packet size |
| 400 | than we allow, trim it so that we don't get overlarge |
| 401 | requests for the client. We can't do this for signed packets. */ |
| 402 | |
| 403 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign)) && !is_sign) |
| 404 | { |
| 405 | unsigned short udpsz; |
| 406 | unsigned char *psave = sizep; |
| 407 | |
| 408 | GETSHORT(udpsz, sizep); |
| 409 | if (udpsz > daemon->edns_pktsz) |
| 410 | PUTSHORT(daemon->edns_pktsz, psave); |
| 411 | } |
| 412 | |
| 413 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
| 414 | return n; |
| 415 | |
| 416 | /* Complain loudly if the upstream server is non-recursive. */ |
| 417 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
| 418 | server && !(server->flags & SERV_WARNED_RECURSIVE)) |
| 419 | { |
| 420 | prettyprint_addr(&server->addr, daemon->namebuff); |
| 421 | my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
| 422 | if (!(daemon->options & OPT_LOG)) |
| 423 | server->flags |= SERV_WARNED_RECURSIVE; |
| 424 | } |
| 425 | |
| 426 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
| 427 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) |
| 428 | { |
| 429 | munged = 1; |
| 430 | header->rcode = NXDOMAIN; |
| 431 | header->aa = 0; |
| 432 | } |
| 433 | else |
| 434 | { |
| 435 | if (header->rcode == NXDOMAIN && |
| 436 | extract_request(header, n, daemon->namebuff, NULL) && |
| 437 | check_for_local_domain(daemon->namebuff, now)) |
| 438 | { |
| 439 | /* if we forwarded a query for a locally known name (because it was for |
| 440 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, |
| 441 | since we know that the domain exists, even if upstream doesn't */ |
| 442 | munged = 1; |
| 443 | header->aa = 1; |
| 444 | header->rcode = NOERROR; |
| 445 | } |
| 446 | |
| 447 | if (extract_addresses(header, n, daemon->namebuff, now)) |
| 448 | { |
| 449 | my_syslog(LOG_WARNING, _("possible DNS-rebind attack detected")); |
| 450 | munged = 1; |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | /* do this after extract_addresses. Ensure NODATA reply and remove |
| 455 | nameserver info. */ |
| 456 | |
| 457 | if (munged) |
| 458 | { |
| 459 | header->ancount = htons(0); |
| 460 | header->nscount = htons(0); |
| 461 | header->arcount = htons(0); |
| 462 | } |
| 463 | |
| 464 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
| 465 | sections of the packet. Find the new length here and put back pseudoheader |
| 466 | if it was removed. */ |
| 467 | return resize_packet(header, n, pheader, plen); |
| 468 | } |
| 469 | |
| 470 | /* sets new last_server */ |
| 471 | void reply_query(int fd, int family, time_t now) |
| 472 | { |
| 473 | /* packet from peer server, extract data for cache, and send to |
| 474 | original requester */ |
| 475 | HEADER *header; |
| 476 | union mysockaddr serveraddr; |
| 477 | struct frec *forward; |
| 478 | socklen_t addrlen = sizeof(serveraddr); |
| 479 | ssize_t n = recvfrom(fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
| 480 | size_t nn; |
| 481 | struct server *server; |
| 482 | |
| 483 | /* packet buffer overwritten */ |
| 484 | daemon->srv_save = NULL; |
| 485 | |
| 486 | /* Determine the address of the server replying so that we can mark that as good */ |
| 487 | serveraddr.sa.sa_family = family; |
| 488 | #ifdef HAVE_IPV6 |
| 489 | if (serveraddr.sa.sa_family == AF_INET6) |
| 490 | serveraddr.in6.sin6_flowinfo = 0; |
| 491 | #endif |
| 492 | |
| 493 | /* spoof check: answer must come from known server, */ |
| 494 | for (server = daemon->servers; server; server = server->next) |
| 495 | if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR)) && |
| 496 | sockaddr_isequal(&server->addr, &serveraddr)) |
| 497 | break; |
| 498 | |
| 499 | header = (HEADER *)daemon->packet; |
| 500 | |
| 501 | if (!server || |
| 502 | n < (int)sizeof(HEADER) || !header->qr || |
| 503 | !(forward = lookup_frec(ntohs(header->id), questions_crc(header, n, daemon->namebuff)))) |
| 504 | return; |
| 505 | |
| 506 | server = forward->sentto; |
| 507 | |
| 508 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && |
| 509 | !(daemon->options & OPT_ORDER) && |
| 510 | forward->forwardall == 0) |
| 511 | /* for broken servers, attempt to send to another one. */ |
| 512 | { |
| 513 | unsigned char *pheader; |
| 514 | size_t plen; |
| 515 | int is_sign; |
| 516 | |
| 517 | /* recreate query from reply */ |
| 518 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign); |
| 519 | if (!is_sign) |
| 520 | { |
| 521 | header->ancount = htons(0); |
| 522 | header->nscount = htons(0); |
| 523 | header->arcount = htons(0); |
| 524 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) |
| 525 | { |
| 526 | header->qr = 0; |
| 527 | header->tc = 0; |
| 528 | forward_query(-1, NULL, NULL, 0, header, nn, now, forward); |
| 529 | return; |
| 530 | } |
| 531 | } |
| 532 | } |
| 533 | |
| 534 | if ((forward->sentto->flags & SERV_TYPE) == 0) |
| 535 | { |
| 536 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) |
| 537 | server = NULL; |
| 538 | else |
| 539 | { |
| 540 | struct server *last_server; |
| 541 | |
| 542 | /* find good server by address if possible, otherwise assume the last one we sent to */ |
| 543 | for (last_server = daemon->servers; last_server; last_server = last_server->next) |
| 544 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && |
| 545 | sockaddr_isequal(&last_server->addr, &serveraddr)) |
| 546 | { |
| 547 | server = last_server; |
| 548 | break; |
| 549 | } |
| 550 | } |
| 551 | if (!(daemon->options & OPT_ALL_SERVERS)) |
| 552 | daemon->last_server = server; |
| 553 | } |
| 554 | |
| 555 | /* If the answer is an error, keep the forward record in place in case |
| 556 | we get a good reply from another server. Kill it when we've |
| 557 | had replies from all to avoid filling the forwarding table when |
| 558 | everything is broken */ |
| 559 | if (forward->forwardall == 0 || --forward->forwardall == 1 || |
| 560 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) |
| 561 | { |
| 562 | if ((nn = process_reply(header, now, server, (size_t)n))) |
| 563 | { |
| 564 | header->id = htons(forward->orig_id); |
| 565 | header->ra = 1; /* recursion if available */ |
| 566 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn, |
| 567 | &forward->source, &forward->dest, forward->iface); |
| 568 | } |
| 569 | free_frec(forward); /* cancel */ |
| 570 | } |
| 571 | } |
| 572 | |
| 573 | |
| 574 | void receive_query(struct listener *listen, time_t now) |
| 575 | { |
| 576 | HEADER *header = (HEADER *)daemon->packet; |
| 577 | union mysockaddr source_addr; |
| 578 | unsigned short type; |
| 579 | struct all_addr dst_addr; |
| 580 | struct in_addr netmask, dst_addr_4; |
| 581 | size_t m; |
| 582 | ssize_t n; |
| 583 | int if_index = 0; |
| 584 | struct iovec iov[1]; |
| 585 | struct msghdr msg; |
| 586 | struct cmsghdr *cmptr; |
| 587 | union { |
| 588 | struct cmsghdr align; /* this ensures alignment */ |
| 589 | #ifdef HAVE_IPV6 |
| 590 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; |
| 591 | #endif |
| 592 | #if defined(HAVE_LINUX_NETWORK) |
| 593 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
| 594 | #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK) |
| 595 | char control[CMSG_SPACE(sizeof(struct in_addr)) + |
| 596 | CMSG_SPACE(sizeof(unsigned int))]; |
| 597 | #elif defined(IP_RECVDSTADDR) |
| 598 | char control[CMSG_SPACE(sizeof(struct in_addr)) + |
| 599 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; |
| 600 | #endif |
| 601 | } control_u; |
| 602 | |
| 603 | /* packet buffer overwritten */ |
| 604 | daemon->srv_save = NULL; |
| 605 | |
| 606 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
| 607 | { |
| 608 | dst_addr_4 = listen->iface->addr.in.sin_addr; |
| 609 | netmask = listen->iface->netmask; |
| 610 | } |
| 611 | else |
| 612 | { |
| 613 | dst_addr_4.s_addr = 0; |
| 614 | netmask.s_addr = 0; |
| 615 | } |
| 616 | |
| 617 | iov[0].iov_base = daemon->packet; |
| 618 | iov[0].iov_len = daemon->edns_pktsz; |
| 619 | |
| 620 | msg.msg_control = control_u.control; |
| 621 | msg.msg_controllen = sizeof(control_u); |
| 622 | msg.msg_flags = 0; |
| 623 | msg.msg_name = &source_addr; |
| 624 | msg.msg_namelen = sizeof(source_addr); |
| 625 | msg.msg_iov = iov; |
| 626 | msg.msg_iovlen = 1; |
| 627 | |
| 628 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
| 629 | return; |
| 630 | |
| 631 | if (n < (int)sizeof(HEADER) || |
| 632 | (msg.msg_flags & MSG_TRUNC) || |
| 633 | header->qr) |
| 634 | return; |
| 635 | |
| 636 | source_addr.sa.sa_family = listen->family; |
| 637 | #ifdef HAVE_IPV6 |
| 638 | if (listen->family == AF_INET6) |
| 639 | source_addr.in6.sin6_flowinfo = 0; |
| 640 | #endif |
| 641 | |
| 642 | if (!(daemon->options & OPT_NOWILD)) |
| 643 | { |
| 644 | struct ifreq ifr; |
| 645 | |
| 646 | if (msg.msg_controllen < sizeof(struct cmsghdr)) |
| 647 | return; |
| 648 | |
| 649 | #if defined(HAVE_LINUX_NETWORK) |
| 650 | if (listen->family == AF_INET) |
| 651 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| 652 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) |
| 653 | { |
| 654 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
| 655 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
| 656 | } |
| 657 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) |
| 658 | if (listen->family == AF_INET) |
| 659 | { |
| 660 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| 661 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) |
| 662 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
| 663 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
| 664 | #ifdef HAVE_SOLARIS_NETWORK |
| 665 | if_index = *((unsigned int *)CMSG_DATA(cmptr)); |
| 666 | #else |
| 667 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; |
| 668 | #endif |
| 669 | } |
| 670 | #endif |
| 671 | |
| 672 | #ifdef HAVE_IPV6 |
| 673 | if (listen->family == AF_INET6) |
| 674 | { |
| 675 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
| 676 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) |
| 677 | { |
| 678 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; |
| 679 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; |
| 680 | } |
| 681 | } |
| 682 | #endif |
| 683 | |
| 684 | /* enforce available interface configuration */ |
| 685 | |
| 686 | if (!indextoname(listen->fd, if_index, ifr.ifr_name) || |
| 687 | !iface_check(listen->family, &dst_addr, ifr.ifr_name, &if_index)) |
| 688 | return; |
| 689 | |
| 690 | if (listen->family == AF_INET && |
| 691 | (daemon->options & OPT_LOCALISE) && |
| 692 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) |
| 693 | return; |
| 694 | |
| 695 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; |
| 696 | } |
| 697 | |
| 698 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
| 699 | { |
| 700 | char types[20]; |
| 701 | |
| 702 | querystr(types, type); |
| 703 | |
| 704 | if (listen->family == AF_INET) |
| 705 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
| 706 | (struct all_addr *)&source_addr.in.sin_addr, types); |
| 707 | #ifdef HAVE_IPV6 |
| 708 | else |
| 709 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
| 710 | (struct all_addr *)&source_addr.in6.sin6_addr, types); |
| 711 | #endif |
| 712 | } |
| 713 | |
| 714 | m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n, |
| 715 | dst_addr_4, netmask, now); |
| 716 | if (m >= 1) |
| 717 | { |
| 718 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, |
| 719 | m, &source_addr, &dst_addr, if_index); |
| 720 | daemon->local_answer++; |
| 721 | } |
| 722 | else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index, |
| 723 | header, (size_t)n, now, NULL)) |
| 724 | daemon->queries_forwarded++; |
| 725 | else |
| 726 | daemon->local_answer++; |
| 727 | } |
| 728 | |
| 729 | /* The daemon forks before calling this: it should deal with one connection, |
| 730 | blocking as neccessary, and then return. Note, need to be a bit careful |
| 731 | about resources for debug mode, when the fork is suppressed: that's |
| 732 | done by the caller. */ |
| 733 | unsigned char *tcp_request(int confd, time_t now, |
| 734 | struct in_addr local_addr, struct in_addr netmask) |
| 735 | { |
| 736 | int size = 0; |
| 737 | size_t m; |
| 738 | unsigned short qtype, gotname; |
| 739 | unsigned char c1, c2; |
| 740 | /* Max TCP packet + slop */ |
| 741 | unsigned char *packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ); |
| 742 | HEADER *header; |
| 743 | struct server *last_server; |
| 744 | |
| 745 | while (1) |
| 746 | { |
| 747 | if (!packet || |
| 748 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || |
| 749 | !(size = c1 << 8 | c2) || |
| 750 | !read_write(confd, packet, size, 1)) |
| 751 | return packet; |
| 752 | |
| 753 | if (size < (int)sizeof(HEADER)) |
| 754 | continue; |
| 755 | |
| 756 | header = (HEADER *)packet; |
| 757 | |
| 758 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
| 759 | { |
| 760 | union mysockaddr peer_addr; |
| 761 | socklen_t peer_len = sizeof(union mysockaddr); |
| 762 | |
| 763 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) |
| 764 | { |
| 765 | char types[20]; |
| 766 | |
| 767 | querystr(types, qtype); |
| 768 | |
| 769 | if (peer_addr.sa.sa_family == AF_INET) |
| 770 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
| 771 | (struct all_addr *)&peer_addr.in.sin_addr, types); |
| 772 | #ifdef HAVE_IPV6 |
| 773 | else |
| 774 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
| 775 | (struct all_addr *)&peer_addr.in6.sin6_addr, types); |
| 776 | #endif |
| 777 | } |
| 778 | } |
| 779 | |
| 780 | /* m > 0 if answered from cache */ |
| 781 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, |
| 782 | local_addr, netmask, now); |
| 783 | |
| 784 | /* Do this by steam now we're not in the select() loop */ |
| 785 | check_log_writer(NULL); |
| 786 | |
| 787 | if (m == 0) |
| 788 | { |
| 789 | unsigned short flags = 0; |
| 790 | struct all_addr *addrp = NULL; |
| 791 | int type = 0; |
| 792 | char *domain = NULL; |
| 793 | |
| 794 | if (gotname) |
| 795 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain); |
| 796 | |
| 797 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
| 798 | last_server = daemon->servers; |
| 799 | else |
| 800 | last_server = daemon->last_server; |
| 801 | |
| 802 | if (!flags && last_server) |
| 803 | { |
| 804 | struct server *firstsendto = NULL; |
| 805 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
| 806 | |
| 807 | /* Loop round available servers until we succeed in connecting to one. |
| 808 | Note that this code subtley ensures that consecutive queries on this connection |
| 809 | which can go to the same server, do so. */ |
| 810 | while (1) |
| 811 | { |
| 812 | if (!firstsendto) |
| 813 | firstsendto = last_server; |
| 814 | else |
| 815 | { |
| 816 | if (!(last_server = last_server->next)) |
| 817 | last_server = daemon->servers; |
| 818 | |
| 819 | if (last_server == firstsendto) |
| 820 | break; |
| 821 | } |
| 822 | |
| 823 | /* server for wrong domain */ |
| 824 | if (type != (last_server->flags & SERV_TYPE) || |
| 825 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) |
| 826 | continue; |
| 827 | |
| 828 | if ((last_server->tcpfd == -1) && |
| 829 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && |
Lorenzo Colitti | 68eff53 | 2014-08-26 14:06:34 -0700 | [diff] [blame] | 830 | (!local_bind(last_server->tcpfd, &last_server->source_addr, |
| 831 | last_server->interface, last_server->mark, 1) || |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 832 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1)) |
| 833 | { |
| 834 | close(last_server->tcpfd); |
| 835 | last_server->tcpfd = -1; |
| 836 | } |
| 837 | |
| 838 | if (last_server->tcpfd == -1) |
| 839 | continue; |
| 840 | |
| 841 | c1 = size >> 8; |
| 842 | c2 = size; |
| 843 | |
| 844 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || |
| 845 | !read_write(last_server->tcpfd, &c2, 1, 0) || |
| 846 | !read_write(last_server->tcpfd, packet, size, 0) || |
| 847 | !read_write(last_server->tcpfd, &c1, 1, 1) || |
| 848 | !read_write(last_server->tcpfd, &c2, 1, 1)) |
| 849 | { |
| 850 | close(last_server->tcpfd); |
| 851 | last_server->tcpfd = -1; |
| 852 | continue; |
| 853 | } |
| 854 | |
| 855 | m = (c1 << 8) | c2; |
| 856 | if (!read_write(last_server->tcpfd, packet, m, 1)) |
| 857 | return packet; |
| 858 | |
| 859 | if (!gotname) |
| 860 | strcpy(daemon->namebuff, "query"); |
| 861 | if (last_server->addr.sa.sa_family == AF_INET) |
| 862 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
| 863 | (struct all_addr *)&last_server->addr.in.sin_addr, NULL); |
| 864 | #ifdef HAVE_IPV6 |
| 865 | else |
| 866 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
| 867 | (struct all_addr *)&last_server->addr.in6.sin6_addr, NULL); |
| 868 | #endif |
| 869 | |
| 870 | /* There's no point in updating the cache, since this process will exit and |
| 871 | lose the information after a few queries. We make this call for the alias and |
| 872 | bogus-nxdomain side-effects. */ |
| 873 | /* If the crc of the question section doesn't match the crc we sent, then |
| 874 | someone might be attempting to insert bogus values into the cache by |
| 875 | sending replies containing questions and bogus answers. */ |
| 876 | if (crc == questions_crc(header, (unsigned int)m, daemon->namebuff)) |
| 877 | m = process_reply(header, now, last_server, (unsigned int)m); |
| 878 | |
| 879 | break; |
| 880 | } |
| 881 | } |
| 882 | |
| 883 | /* In case of local answer or no connections made. */ |
| 884 | if (m == 0) |
| 885 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
| 886 | } |
| 887 | |
| 888 | check_log_writer(NULL); |
| 889 | |
| 890 | c1 = m>>8; |
| 891 | c2 = m; |
| 892 | if (!read_write(confd, &c1, 1, 0) || |
| 893 | !read_write(confd, &c2, 1, 0) || |
| 894 | !read_write(confd, packet, m, 0)) |
| 895 | return packet; |
| 896 | } |
| 897 | } |
| 898 | |
| 899 | static struct frec *allocate_frec(time_t now) |
| 900 | { |
| 901 | struct frec *f; |
| 902 | |
| 903 | if ((f = (struct frec *)whine_malloc(sizeof(struct frec)))) |
| 904 | { |
| 905 | f->next = daemon->frec_list; |
| 906 | f->time = now; |
| 907 | f->sentto = NULL; |
| 908 | f->rfd4 = NULL; |
| 909 | #ifdef HAVE_IPV6 |
| 910 | f->rfd6 = NULL; |
| 911 | #endif |
| 912 | daemon->frec_list = f; |
| 913 | } |
| 914 | |
| 915 | return f; |
| 916 | } |
| 917 | |
| 918 | static struct randfd *allocate_rfd(int family) |
| 919 | { |
| 920 | static int finger = 0; |
| 921 | int i; |
| 922 | |
| 923 | /* limit the number of sockets we have open to avoid starvation of |
| 924 | (eg) TFTP. Once we have a reasonable number, randomness should be OK */ |
| 925 | |
| 926 | for (i = 0; i < RANDOM_SOCKS; i++) |
| 927 | if (daemon->randomsocks[i].refcount == 0) |
| 928 | { |
| 929 | if ((daemon->randomsocks[i].fd = random_sock(family)) == -1) |
| 930 | break; |
| 931 | |
| 932 | daemon->randomsocks[i].refcount = 1; |
| 933 | daemon->randomsocks[i].family = family; |
| 934 | return &daemon->randomsocks[i]; |
| 935 | } |
| 936 | |
| 937 | /* No free ones or cannot get new socket, grab an existing one */ |
| 938 | for (i = 0; i < RANDOM_SOCKS; i++) |
| 939 | { |
| 940 | int j = (i+finger) % RANDOM_SOCKS; |
| 941 | if (daemon->randomsocks[j].refcount != 0 && |
| 942 | daemon->randomsocks[j].family == family && |
| 943 | daemon->randomsocks[j].refcount != 0xffff) |
| 944 | { |
| 945 | finger = j; |
| 946 | daemon->randomsocks[j].refcount++; |
| 947 | return &daemon->randomsocks[j]; |
| 948 | } |
| 949 | } |
| 950 | |
| 951 | return NULL; /* doom */ |
| 952 | } |
| 953 | |
| 954 | static void free_frec(struct frec *f) |
| 955 | { |
| 956 | if (f->rfd4 && --(f->rfd4->refcount) == 0) |
| 957 | close(f->rfd4->fd); |
| 958 | |
| 959 | f->rfd4 = NULL; |
| 960 | f->sentto = NULL; |
| 961 | |
| 962 | #ifdef HAVE_IPV6 |
| 963 | if (f->rfd6 && --(f->rfd6->refcount) == 0) |
| 964 | close(f->rfd6->fd); |
| 965 | |
| 966 | f->rfd6 = NULL; |
| 967 | #endif |
| 968 | } |
| 969 | |
| 970 | /* if wait==NULL return a free or older than TIMEOUT record. |
| 971 | else return *wait zero if one available, or *wait is delay to |
| 972 | when the oldest in-use record will expire. Impose an absolute |
| 973 | limit of 4*TIMEOUT before we wipe things (for random sockets) */ |
| 974 | struct frec *get_new_frec(time_t now, int *wait) |
| 975 | { |
| 976 | struct frec *f, *oldest, *target; |
| 977 | int count; |
| 978 | |
| 979 | if (wait) |
| 980 | *wait = 0; |
| 981 | |
| 982 | for (f = daemon->frec_list, oldest = NULL, target = NULL, count = 0; f; f = f->next, count++) |
| 983 | if (!f->sentto) |
| 984 | target = f; |
| 985 | else |
| 986 | { |
| 987 | if (difftime(now, f->time) >= 4*TIMEOUT) |
| 988 | { |
| 989 | free_frec(f); |
| 990 | target = f; |
| 991 | } |
| 992 | |
| 993 | if (!oldest || difftime(f->time, oldest->time) <= 0) |
| 994 | oldest = f; |
| 995 | } |
| 996 | |
| 997 | if (target) |
| 998 | { |
| 999 | target->time = now; |
| 1000 | return target; |
| 1001 | } |
| 1002 | |
| 1003 | /* can't find empty one, use oldest if there is one |
| 1004 | and it's older than timeout */ |
| 1005 | if (oldest && ((int)difftime(now, oldest->time)) >= TIMEOUT) |
| 1006 | { |
| 1007 | /* keep stuff for twice timeout if we can by allocating a new |
| 1008 | record instead */ |
| 1009 | if (difftime(now, oldest->time) < 2*TIMEOUT && |
| 1010 | count <= daemon->ftabsize && |
| 1011 | (f = allocate_frec(now))) |
| 1012 | return f; |
| 1013 | |
| 1014 | if (!wait) |
| 1015 | { |
| 1016 | free_frec(oldest); |
| 1017 | oldest->time = now; |
| 1018 | } |
| 1019 | return oldest; |
| 1020 | } |
| 1021 | |
| 1022 | /* none available, calculate time 'till oldest record expires */ |
| 1023 | if (count > daemon->ftabsize) |
| 1024 | { |
| 1025 | if (oldest && wait) |
| 1026 | *wait = oldest->time + (time_t)TIMEOUT - now; |
| 1027 | return NULL; |
| 1028 | } |
| 1029 | |
| 1030 | if (!(f = allocate_frec(now)) && wait) |
| 1031 | /* wait one second on malloc failure */ |
| 1032 | *wait = 1; |
| 1033 | |
| 1034 | return f; /* OK if malloc fails and this is NULL */ |
| 1035 | } |
| 1036 | |
| 1037 | /* crc is all-ones if not known. */ |
| 1038 | static struct frec *lookup_frec(unsigned short id, unsigned int crc) |
| 1039 | { |
| 1040 | struct frec *f; |
| 1041 | |
| 1042 | for(f = daemon->frec_list; f; f = f->next) |
| 1043 | if (f->sentto && f->new_id == id && |
| 1044 | (f->crc == crc || crc == 0xffffffff)) |
| 1045 | return f; |
| 1046 | |
| 1047 | return NULL; |
| 1048 | } |
| 1049 | |
| 1050 | static struct frec *lookup_frec_by_sender(unsigned short id, |
| 1051 | union mysockaddr *addr, |
| 1052 | unsigned int crc) |
| 1053 | { |
| 1054 | struct frec *f; |
| 1055 | |
| 1056 | for(f = daemon->frec_list; f; f = f->next) |
| 1057 | if (f->sentto && |
| 1058 | f->orig_id == id && |
| 1059 | f->crc == crc && |
| 1060 | sockaddr_isequal(&f->source, addr)) |
| 1061 | return f; |
| 1062 | |
| 1063 | return NULL; |
| 1064 | } |
| 1065 | |
| 1066 | /* A server record is going away, remove references to it */ |
| 1067 | void server_gone(struct server *server) |
| 1068 | { |
| 1069 | struct frec *f; |
| 1070 | |
| 1071 | for (f = daemon->frec_list; f; f = f->next) |
| 1072 | if (f->sentto && f->sentto == server) |
| 1073 | free_frec(f); |
| 1074 | |
| 1075 | if (daemon->last_server == server) |
| 1076 | daemon->last_server = NULL; |
| 1077 | |
| 1078 | if (daemon->srv_save == server) |
| 1079 | daemon->srv_save = NULL; |
| 1080 | } |
| 1081 | |
| 1082 | /* return unique random ids. |
| 1083 | For signed packets we can't change the ID without breaking the |
| 1084 | signing, so we keep the same one. In this case force is set, and this |
| 1085 | routine degenerates into killing any conflicting forward record. */ |
| 1086 | static unsigned short get_id(int force, unsigned short force_id, unsigned int crc) |
| 1087 | { |
| 1088 | unsigned short ret = 0; |
| 1089 | |
| 1090 | if (force) |
| 1091 | { |
| 1092 | struct frec *f = lookup_frec(force_id, crc); |
| 1093 | if (f) |
| 1094 | free_frec(f); /* free */ |
| 1095 | ret = force_id; |
| 1096 | } |
| 1097 | else do |
| 1098 | ret = rand16(); |
| 1099 | while (lookup_frec(ret, crc)); |
| 1100 | |
| 1101 | return ret; |
| 1102 | } |
| 1103 | |
| 1104 | |
| 1105 | |
| 1106 | |
| 1107 | |