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f6b7dc47 | 1 | /* dnsmasq is Copyright (c) 2000 - 2005 Simon Kelley |
9e4abcb5 SK |
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. | |
6 | ||
7 | This program is distributed in the hope that it will be useful, | |
8 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | GNU General Public License for more details. | |
11 | */ | |
12 | ||
9e4abcb5 SK |
13 | #include "dnsmasq.h" |
14 | ||
15 | static struct frec *frec_list; | |
16 | ||
17 | static struct frec *get_new_frec(time_t now); | |
18 | static struct frec *lookup_frec(unsigned short id); | |
19 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
20 | union mysockaddr *addr, |
21 | unsigned int crc); | |
9e4abcb5 SK |
22 | static unsigned short get_id(void); |
23 | ||
24 | /* May be called more than once. */ | |
25 | void forward_init(int first) | |
26 | { | |
27 | struct frec *f; | |
feba5c1d | 28 | |
9e4abcb5 SK |
29 | if (first) |
30 | frec_list = NULL; | |
31 | for (f = frec_list; f; f = f->next) | |
32 | f->new_id = 0; | |
33 | } | |
34 | ||
44a2a316 SK |
35 | /* Send a UDP packet with it's source address set as "source" |
36 | unless nowild is true, when we just send it with the kernel default */ | |
cdeda28f | 37 | static void send_from(int fd, int nowild, char *packet, size_t len, |
dfa666f2 SK |
38 | union mysockaddr *to, struct all_addr *source, |
39 | unsigned int iface) | |
9e4abcb5 | 40 | { |
44a2a316 SK |
41 | struct msghdr msg; |
42 | struct iovec iov[1]; | |
44a2a316 SK |
43 | union { |
44 | struct cmsghdr align; /* this ensures alignment */ | |
5e9e0efb | 45 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 SK |
46 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
47 | #elif defined(IP_SENDSRCADDR) | |
48 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
49 | #endif | |
50 | #ifdef HAVE_IPV6 | |
51 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
52 | #endif | |
53 | } control_u; | |
feba5c1d | 54 | |
44a2a316 SK |
55 | iov[0].iov_base = packet; |
56 | iov[0].iov_len = len; | |
57 | ||
feba5c1d SK |
58 | msg.msg_control = NULL; |
59 | msg.msg_controllen = 0; | |
44a2a316 SK |
60 | msg.msg_flags = 0; |
61 | msg.msg_name = to; | |
62 | msg.msg_namelen = sa_len(to); | |
63 | msg.msg_iov = iov; | |
64 | msg.msg_iovlen = 1; | |
feba5c1d | 65 | |
26128d27 | 66 | if (!nowild) |
44a2a316 | 67 | { |
26128d27 | 68 | struct cmsghdr *cmptr; |
feba5c1d SK |
69 | msg.msg_control = &control_u; |
70 | msg.msg_controllen = sizeof(control_u); | |
26128d27 SK |
71 | cmptr = CMSG_FIRSTHDR(&msg); |
72 | ||
73 | if (to->sa.sa_family == AF_INET) | |
74 | { | |
5e9e0efb | 75 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
76 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
77 | pkt->ipi_ifindex = 0; | |
78 | pkt->ipi_spec_dst = source->addr.addr4; | |
79 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
80 | cmptr->cmsg_level = SOL_IP; | |
81 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 82 | #elif defined(IP_SENDSRCADDR) |
26128d27 SK |
83 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
84 | *a = source->addr.addr4; | |
85 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
86 | cmptr->cmsg_level = IPPROTO_IP; | |
87 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 88 | #endif |
26128d27 | 89 | } |
26128d27 | 90 | else |
b8187c80 | 91 | #ifdef HAVE_IPV6 |
26128d27 SK |
92 | { |
93 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
94 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
95 | pkt->ipi6_addr = source->addr.addr6; | |
96 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
97 | cmptr->cmsg_type = IPV6_PKTINFO; | |
98 | cmptr->cmsg_level = IPV6_LEVEL; | |
99 | } | |
3d8df260 SK |
100 | #else |
101 | iface = 0; /* eliminate warning */ | |
44a2a316 | 102 | #endif |
26128d27 | 103 | } |
feba5c1d | 104 | |
fd9fa481 SK |
105 | retry: |
106 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 107 | { |
fd9fa481 SK |
108 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
109 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
110 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
111 | if (errno == EINVAL && msg.msg_controllen) | |
112 | { | |
113 | msg.msg_controllen = 0; | |
114 | goto retry; | |
115 | } | |
116 | if (retry_send()) | |
117 | goto retry; | |
feba5c1d | 118 | } |
9e4abcb5 | 119 | } |
44a2a316 | 120 | |
36717eee SK |
121 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
122 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
123 | |
124 | { | |
125 | /* If the query ends in the domain in one of our servers, set | |
126 | domain to point to that name. We find the largest match to allow both | |
127 | domain.org and sub.domain.org to exist. */ | |
128 | ||
129 | unsigned int namelen = strlen(qdomain); | |
130 | unsigned int matchlen = 0; | |
131 | struct server *serv; | |
132 | unsigned short flags = 0; | |
133 | ||
3be34541 | 134 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 135 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 136 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d SK |
137 | { |
138 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
139 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 140 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
141 | flags = F_NXDOMAIN; |
142 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
143 | { | |
144 | if (sflag & qtype) | |
145 | { | |
146 | flags = sflag; | |
147 | if (serv->addr.sa.sa_family == AF_INET) | |
148 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 149 | #ifdef HAVE_IPV6 |
36717eee SK |
150 | else |
151 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 152 | #endif |
36717eee SK |
153 | } |
154 | else if (!flags) | |
155 | flags = F_NOERR; | |
156 | } | |
feba5c1d SK |
157 | } |
158 | else if (serv->flags & SERV_HAS_DOMAIN) | |
159 | { | |
160 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 161 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 162 | if (namelen >= domainlen && |
b8187c80 SK |
163 | hostname_isequal(matchstart, serv->domain) && |
164 | domainlen >= matchlen && | |
cdeda28f | 165 | (domainlen == 0 || namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) |
feba5c1d SK |
166 | { |
167 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
168 | *type = SERV_HAS_DOMAIN; | |
169 | *domain = serv->domain; | |
170 | matchlen = domainlen; | |
feba5c1d | 171 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
172 | flags = F_NXDOMAIN; |
173 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 174 | { |
36717eee SK |
175 | if ((sflag | F_QUERY ) & qtype) |
176 | { | |
177 | flags = qtype; | |
178 | if (serv->addr.sa.sa_family == AF_INET) | |
179 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 180 | #ifdef HAVE_IPV6 |
36717eee SK |
181 | else |
182 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 183 | #endif |
36717eee SK |
184 | } |
185 | else if (!flags) | |
186 | flags = F_NOERR; | |
feba5c1d SK |
187 | } |
188 | } | |
189 | } | |
190 | ||
36717eee | 191 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
192 | { |
193 | if (flags & F_QUERY) | |
fd9fa481 | 194 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0, NULL, 0); |
feba5c1d | 195 | else |
fd9fa481 | 196 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0, NULL, 0); |
feba5c1d | 197 | } |
3d8df260 | 198 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
36717eee SK |
199 | flags = F_NXDOMAIN; |
200 | ||
f6b7dc47 | 201 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon)) |
c1bb8504 | 202 | flags = F_NOERR; |
feba5c1d | 203 | |
36717eee | 204 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
fd9fa481 | 205 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0, NULL, 0); |
feba5c1d SK |
206 | |
207 | return flags; | |
208 | } | |
44a2a316 | 209 | |
9e4abcb5 | 210 | /* returns new last_server */ |
3be34541 SK |
211 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
212 | struct all_addr *dst_addr, unsigned int dst_iface, | |
cdeda28f | 213 | HEADER *header, size_t plen, time_t now, struct frec *forward) |
9e4abcb5 | 214 | { |
9e4abcb5 | 215 | char *domain = NULL; |
0a852541 | 216 | int type = 0; |
9e4abcb5 | 217 | struct all_addr *addrp = NULL; |
cdeda28f | 218 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
9e4abcb5 | 219 | unsigned short flags = 0; |
cdeda28f | 220 | unsigned short gotname = extract_request(header, plen, daemon->namebuff, NULL); |
de37951c | 221 | struct server *start = NULL; |
3d8df260 SK |
222 | |
223 | /* may be no servers available. */ | |
224 | if (!daemon->servers) | |
9e4abcb5 | 225 | forward = NULL; |
b8187c80 | 226 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 227 | { |
de37951c | 228 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 229 | domain = forward->sentto->domain; |
3be34541 | 230 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 231 | { |
0a852541 | 232 | forward->forwardall = 1; |
3be34541 | 233 | daemon->last_server = NULL; |
de37951c | 234 | } |
9e4abcb5 | 235 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 236 | if (!(start = forward->sentto->next)) |
3be34541 | 237 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
238 | header->id = htons(forward->new_id); |
239 | } | |
240 | else | |
241 | { | |
242 | if (gotname) | |
36717eee | 243 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 244 | |
feba5c1d SK |
245 | if (!flags && !(forward = get_new_frec(now))) |
246 | /* table full - server failure. */ | |
247 | flags = F_NEG; | |
9e4abcb5 SK |
248 | |
249 | if (forward) | |
250 | { | |
0a852541 SK |
251 | forward->source = *udpaddr; |
252 | forward->dest = *dst_addr; | |
253 | forward->iface = dst_iface; | |
254 | forward->new_id = get_id(); | |
255 | forward->fd = udpfd; | |
256 | forward->orig_id = ntohs(header->id); | |
257 | forward->crc = crc; | |
258 | forward->forwardall = 0; | |
259 | header->id = htons(forward->new_id); | |
260 | ||
9e4abcb5 SK |
261 | /* In strict_order mode, or when using domain specific servers |
262 | always try servers in the order specified in resolv.conf, | |
263 | otherwise, use the one last known to work. */ | |
264 | ||
3be34541 SK |
265 | if (type != 0 || (daemon->options & OPT_ORDER)) |
266 | start = daemon->servers; | |
267 | else if (!(start = daemon->last_server)) | |
de37951c | 268 | { |
3be34541 | 269 | start = daemon->servers; |
0a852541 | 270 | forward->forwardall = 1; |
de37951c | 271 | } |
9e4abcb5 SK |
272 | } |
273 | } | |
feba5c1d | 274 | |
9e4abcb5 SK |
275 | /* check for send errors here (no route to host) |
276 | if we fail to send to all nameservers, send back an error | |
277 | packet straight away (helps modem users when offline) */ | |
278 | ||
279 | if (!flags && forward) | |
280 | { | |
de37951c SK |
281 | struct server *firstsentto = start; |
282 | int forwarded = 0; | |
283 | ||
9e4abcb5 SK |
284 | while (1) |
285 | { | |
9e4abcb5 SK |
286 | /* only send to servers dealing with our domain. |
287 | domain may be NULL, in which case server->domain | |
288 | must be NULL also. */ | |
289 | ||
de37951c | 290 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
291 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
292 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 293 | { |
fd9fa481 | 294 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 295 | &start->addr.sa, |
fd9fa481 SK |
296 | sa_len(&start->addr)) == -1) |
297 | { | |
298 | if (retry_send()) | |
299 | continue; | |
300 | } | |
301 | else | |
9e4abcb5 | 302 | { |
cdeda28f SK |
303 | /* Keep info in case we want to re-send this packet */ |
304 | daemon->srv_save = start; | |
305 | daemon->packet_len = plen; | |
306 | ||
de37951c | 307 | if (!gotname) |
3be34541 | 308 | strcpy(daemon->namebuff, "query"); |
de37951c | 309 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 310 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
311 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
312 | NULL, 0); | |
de37951c SK |
313 | #ifdef HAVE_IPV6 |
314 | else | |
3be34541 | 315 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
316 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
317 | NULL, 0); | |
de37951c SK |
318 | #endif |
319 | forwarded = 1; | |
320 | forward->sentto = start; | |
0a852541 | 321 | if (!forward->forwardall) |
de37951c | 322 | break; |
0a852541 | 323 | forward->forwardall++; |
9e4abcb5 SK |
324 | } |
325 | } | |
326 | ||
de37951c | 327 | if (!(start = start->next)) |
3be34541 | 328 | start = daemon->servers; |
9e4abcb5 | 329 | |
de37951c | 330 | if (start == firstsentto) |
9e4abcb5 SK |
331 | break; |
332 | } | |
333 | ||
de37951c | 334 | if (forwarded) |
3be34541 | 335 | return; |
de37951c | 336 | |
9e4abcb5 SK |
337 | /* could not send on, prepare to return */ |
338 | header->id = htons(forward->orig_id); | |
339 | forward->new_id = 0; /* cancel */ | |
340 | } | |
341 | ||
342 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
343 | if (udpfd != -1) |
344 | { | |
cdeda28f | 345 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
b8187c80 SK |
346 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); |
347 | } | |
348 | ||
3be34541 | 349 | return; |
9e4abcb5 SK |
350 | } |
351 | ||
cdeda28f | 352 | static size_t process_reply(struct daemon *daemon, HEADER *header, time_t now, |
5e9e0efb | 353 | unsigned int query_crc, struct server *server, size_t n) |
feba5c1d | 354 | { |
36717eee | 355 | unsigned char *pheader, *sizep; |
cdeda28f SK |
356 | int munged = 0; |
357 | size_t plen; | |
358 | ||
feba5c1d SK |
359 | /* If upstream is advertising a larger UDP packet size |
360 | than we allow, trim it so that we don't get overlarge | |
361 | requests for the client. */ | |
362 | ||
36717eee | 363 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
364 | { |
365 | unsigned short udpsz; | |
36717eee | 366 | unsigned char *psave = sizep; |
feba5c1d | 367 | |
36717eee | 368 | GETSHORT(udpsz, sizep); |
3be34541 SK |
369 | if (udpsz > daemon->edns_pktsz) |
370 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
371 | } |
372 | ||
0a852541 SK |
373 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
374 | return n; | |
375 | ||
feba5c1d | 376 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
377 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
378 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 379 | { |
3d8df260 | 380 | prettyprint_addr(&server->addr, daemon->namebuff); |
b8187c80 | 381 | syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
0a852541 SK |
382 | if (!(daemon->options & OPT_LOG)) |
383 | server->flags |= SERV_WARNED_RECURSIVE; | |
384 | } | |
385 | ||
fd9fa481 SK |
386 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
387 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 388 | { |
fd9fa481 SK |
389 | munged = 1; |
390 | header->rcode = NXDOMAIN; | |
391 | header->aa = 0; | |
36717eee | 392 | } |
fd9fa481 | 393 | else |
36717eee | 394 | { |
fd9fa481 SK |
395 | if (header->rcode == NXDOMAIN && |
396 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 397 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
398 | { |
399 | /* if we forwarded a query for a locally known name (because it was for | |
400 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
401 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
402 | munged = 1; |
403 | header->aa = 1; | |
404 | header->rcode = NOERROR; | |
feba5c1d | 405 | } |
fd9fa481 | 406 | |
0a852541 SK |
407 | /* If the crc of the question section doesn't match the crc we sent, then |
408 | someone might be attempting to insert bogus values into the cache by | |
409 | sending replies containing questions and bogus answers. */ | |
410 | if (query_crc == questions_crc(header, n, daemon->namebuff)) | |
411 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 412 | } |
fd9fa481 SK |
413 | |
414 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
415 | nameserver info. */ | |
416 | ||
417 | if (munged) | |
418 | { | |
419 | header->ancount = htons(0); | |
420 | header->nscount = htons(0); | |
421 | header->arcount = htons(0); | |
422 | } | |
423 | ||
36717eee SK |
424 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
425 | sections of the packet. Find the new length here and put back pseudoheader | |
426 | if it was removed. */ | |
427 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
428 | } |
429 | ||
3be34541 SK |
430 | /* sets new last_server */ |
431 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
432 | { |
433 | /* packet from peer server, extract data for cache, and send to | |
434 | original requester */ | |
435 | struct frec *forward; | |
436 | HEADER *header; | |
de37951c SK |
437 | union mysockaddr serveraddr; |
438 | socklen_t addrlen = sizeof(serveraddr); | |
cdeda28f SK |
439 | ssize_t n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
440 | size_t nn; | |
441 | ||
442 | /* packet buffer overwritten */ | |
443 | daemon->srv_save = NULL; | |
444 | ||
de37951c SK |
445 | /* Determine the address of the server replying so that we can mark that as good */ |
446 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
447 | #ifdef HAVE_IPV6 | |
448 | if (serveraddr.sa.sa_family == AF_INET6) | |
5e9e0efb | 449 | serveraddr.in6.sin6_flowinfo = 0; |
de37951c | 450 | #endif |
9e4abcb5 | 451 | |
3be34541 | 452 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
453 | forward = lookup_frec(ntohs(header->id)); |
454 | ||
455 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 456 | { |
0a852541 SK |
457 | struct server *server = forward->sentto; |
458 | ||
b8187c80 SK |
459 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && forward->forwardall == 0) |
460 | /* for broken servers, attempt to send to another one. */ | |
461 | { | |
462 | unsigned char *pheader; | |
cdeda28f SK |
463 | size_t plen; |
464 | ||
b8187c80 | 465 | /* recreate query from reply */ |
cdeda28f | 466 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL); |
b8187c80 SK |
467 | header->ancount = htons(0); |
468 | header->nscount = htons(0); | |
469 | header->arcount = htons(0); | |
cdeda28f | 470 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) |
b8187c80 SK |
471 | { |
472 | forward->forwardall = 1; | |
473 | header->qr = 0; | |
474 | header->tc = 0; | |
475 | forward_query(daemon, -1, NULL, NULL, 0, header, nn, now, forward); | |
476 | return; | |
477 | } | |
478 | } | |
479 | ||
0a852541 SK |
480 | if ((forward->sentto->flags & SERV_TYPE) == 0) |
481 | { | |
482 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
483 | server = NULL; | |
484 | else | |
b8187c80 SK |
485 | { |
486 | struct server *last_server; | |
487 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
488 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
489 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
490 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
491 | { | |
492 | server = last_server; | |
493 | break; | |
494 | } | |
495 | } | |
0a852541 SK |
496 | daemon->last_server = server; |
497 | } | |
b8187c80 | 498 | |
0a852541 SK |
499 | /* If the answer is an error, keep the forward record in place in case |
500 | we get a good reply from another server. Kill it when we've | |
501 | had replies from all to avoid filling the forwarding table when | |
502 | everything is broken */ | |
503 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
504 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
b8187c80 | 505 | { |
cdeda28f | 506 | if ((nn = process_reply(daemon, header, now, forward->crc, server, (size_t)n))) |
b8187c80 SK |
507 | { |
508 | header->id = htons(forward->orig_id); | |
509 | header->ra = 1; /* recursion if available */ | |
cdeda28f | 510 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn, |
b8187c80 SK |
511 | &forward->source, &forward->dest, forward->iface); |
512 | } | |
513 | forward->new_id = 0; /* cancel */ | |
514 | } | |
9e4abcb5 | 515 | } |
9e4abcb5 | 516 | } |
44a2a316 | 517 | |
3be34541 | 518 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 519 | { |
3be34541 | 520 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 521 | union mysockaddr source_addr; |
c1bb8504 | 522 | unsigned short type; |
44a2a316 | 523 | struct all_addr dst_addr; |
f6b7dc47 | 524 | struct in_addr netmask, dst_addr_4; |
cdeda28f SK |
525 | size_t m; |
526 | ssize_t n; | |
527 | int if_index = 0; | |
44a2a316 SK |
528 | struct iovec iov[1]; |
529 | struct msghdr msg; | |
530 | struct cmsghdr *cmptr; | |
44a2a316 SK |
531 | union { |
532 | struct cmsghdr align; /* this ensures alignment */ | |
533 | #ifdef HAVE_IPV6 | |
534 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
535 | #endif | |
5e9e0efb | 536 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 SK |
537 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
538 | #elif defined(IP_RECVDSTADDR) | |
539 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
540 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
541 | #endif | |
542 | } control_u; | |
543 | ||
cdeda28f SK |
544 | /* packet buffer overwritten */ |
545 | daemon->srv_save = NULL; | |
546 | ||
f6b7dc47 SK |
547 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
548 | { | |
549 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
550 | netmask = listen->iface->netmask; | |
551 | } | |
552 | else | |
3d8df260 SK |
553 | { |
554 | dst_addr_4.s_addr = 0; | |
555 | netmask.s_addr = 0; | |
556 | } | |
f6b7dc47 | 557 | |
3be34541 SK |
558 | iov[0].iov_base = daemon->packet; |
559 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
560 | |
561 | msg.msg_control = control_u.control; | |
562 | msg.msg_controllen = sizeof(control_u); | |
563 | msg.msg_flags = 0; | |
564 | msg.msg_name = &source_addr; | |
565 | msg.msg_namelen = sizeof(source_addr); | |
566 | msg.msg_iov = iov; | |
567 | msg.msg_iovlen = 1; | |
568 | ||
de37951c | 569 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 570 | return; |
44a2a316 | 571 | |
5e9e0efb SK |
572 | if (n < (int)sizeof(HEADER) || |
573 | (msg.msg_flags & MSG_TRUNC) || | |
574 | header->qr) | |
26128d27 SK |
575 | return; |
576 | ||
44a2a316 SK |
577 | source_addr.sa.sa_family = listen->family; |
578 | #ifdef HAVE_IPV6 | |
579 | if (listen->family == AF_INET6) | |
5e9e0efb | 580 | source_addr.in6.sin6_flowinfo = 0; |
44a2a316 SK |
581 | #endif |
582 | ||
26128d27 SK |
583 | if (!(daemon->options & OPT_NOWILD)) |
584 | { | |
585 | struct ifreq ifr; | |
586 | ||
587 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
588 | return; | |
44a2a316 | 589 | |
5e9e0efb | 590 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
591 | if (listen->family == AF_INET) |
592 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
593 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
594 | { | |
f6b7dc47 | 595 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
596 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
597 | } | |
598 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
599 | if (listen->family == AF_INET) | |
44a2a316 | 600 | { |
26128d27 SK |
601 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
602 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 603 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
604 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
605 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 606 | } |
44a2a316 | 607 | #endif |
26128d27 | 608 | |
44a2a316 | 609 | #ifdef HAVE_IPV6 |
26128d27 SK |
610 | if (listen->family == AF_INET6) |
611 | { | |
612 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
613 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
614 | { | |
615 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
616 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
617 | } | |
618 | } | |
44a2a316 | 619 | #endif |
26128d27 SK |
620 | |
621 | /* enforce available interface configuration */ | |
622 | ||
8a911ccc | 623 | if (if_index == 0) |
3be34541 | 624 | return; |
44a2a316 | 625 | |
f6b7dc47 | 626 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
627 | { |
628 | #ifdef SIOCGIFNAME | |
629 | ifr.ifr_ifindex = if_index; | |
630 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 631 | return; |
8a911ccc SK |
632 | #else |
633 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 634 | return; |
8a911ccc | 635 | #endif |
f6b7dc47 SK |
636 | |
637 | if (listen->family == AF_INET && | |
638 | (daemon->options & OPT_LOCALISE) && | |
639 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
640 | return; | |
641 | ||
642 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
643 | } |
644 | ||
5e9e0efb SK |
645 | if (!iface_check(daemon, listen->family, &dst_addr, ifr.ifr_name)) |
646 | return; | |
44a2a316 SK |
647 | } |
648 | ||
cdeda28f | 649 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
44a2a316 SK |
650 | { |
651 | if (listen->family == AF_INET) | |
3be34541 | 652 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 653 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
654 | #ifdef HAVE_IPV6 |
655 | else | |
3be34541 | 656 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 657 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
658 | #endif |
659 | } | |
660 | ||
cdeda28f | 661 | m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n, daemon, |
f6b7dc47 | 662 | dst_addr_4, netmask, now); |
44a2a316 | 663 | if (m >= 1) |
3be34541 | 664 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 665 | else |
3be34541 | 666 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
cdeda28f | 667 | header, (size_t)n, now, NULL); |
44a2a316 SK |
668 | } |
669 | ||
3d8df260 | 670 | static int read_write(int fd, unsigned char *packet, int size, int rw) |
feba5c1d | 671 | { |
cdeda28f | 672 | ssize_t n, done; |
feba5c1d SK |
673 | |
674 | for (done = 0; done < size; done += n) | |
675 | { | |
676 | retry: | |
677 | if (rw) | |
678 | n = read(fd, &packet[done], (size_t)(size - done)); | |
679 | else | |
680 | n = write(fd, &packet[done], (size_t)(size - done)); | |
681 | ||
682 | if (n == 0) | |
683 | return 0; | |
684 | else if (n == -1) | |
685 | { | |
5e9e0efb | 686 | if (errno == EINTR) |
feba5c1d | 687 | goto retry; |
feba5c1d SK |
688 | else |
689 | return 0; | |
690 | } | |
691 | } | |
692 | return 1; | |
693 | } | |
694 | ||
695 | /* The daemon forks before calling this: it should deal with one connection, | |
696 | blocking as neccessary, and then return. Note, need to be a bit careful | |
697 | about resources for debug mode, when the fork is suppressed: that's | |
698 | done by the caller. */ | |
3d8df260 SK |
699 | unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, |
700 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d | 701 | { |
cdeda28f SK |
702 | int size = 0; |
703 | size_t m; | |
c1bb8504 | 704 | unsigned short qtype, gotname; |
feba5c1d SK |
705 | unsigned char c1, c2; |
706 | /* Max TCP packet + slop */ | |
3d8df260 | 707 | unsigned char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 708 | HEADER *header; |
3be34541 SK |
709 | struct server *last_server; |
710 | ||
feba5c1d SK |
711 | while (1) |
712 | { | |
713 | if (!packet || | |
714 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
715 | !(size = c1 << 8 | c2) || | |
716 | !read_write(confd, packet, size, 1)) | |
717 | return packet; | |
718 | ||
719 | if (size < (int)sizeof(HEADER)) | |
720 | continue; | |
721 | ||
722 | header = (HEADER *)packet; | |
723 | ||
3be34541 | 724 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
725 | { |
726 | union mysockaddr peer_addr; | |
727 | socklen_t peer_len = sizeof(union mysockaddr); | |
728 | ||
729 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
730 | { | |
731 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 732 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 733 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
734 | #ifdef HAVE_IPV6 |
735 | else | |
3be34541 | 736 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 737 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
738 | #endif |
739 | } | |
740 | } | |
741 | ||
742 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
743 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
744 | local_addr, netmask, now); | |
feba5c1d SK |
745 | |
746 | if (m == 0) | |
747 | { | |
748 | unsigned short flags = 0; | |
feba5c1d SK |
749 | struct all_addr *addrp = NULL; |
750 | int type = 0; | |
751 | char *domain = NULL; | |
752 | ||
753 | if (gotname) | |
36717eee | 754 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 755 | |
3be34541 SK |
756 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
757 | last_server = daemon->servers; | |
758 | else | |
759 | last_server = daemon->last_server; | |
feba5c1d SK |
760 | |
761 | if (!flags && last_server) | |
762 | { | |
763 | struct server *firstsendto = NULL; | |
0a852541 SK |
764 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
765 | ||
feba5c1d SK |
766 | /* Loop round available servers until we succeed in connecting to one. |
767 | Note that this code subtley ensures that consecutive queries on this connection | |
768 | which can go to the same server, do so. */ | |
769 | while (1) | |
770 | { | |
771 | if (!firstsendto) | |
772 | firstsendto = last_server; | |
773 | else | |
774 | { | |
775 | if (!(last_server = last_server->next)) | |
3be34541 | 776 | last_server = daemon->servers; |
feba5c1d SK |
777 | |
778 | if (last_server == firstsendto) | |
779 | break; | |
780 | } | |
781 | ||
782 | /* server for wrong domain */ | |
783 | if (type != (last_server->flags & SERV_TYPE) || | |
784 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
785 | continue; | |
786 | ||
787 | if ((last_server->tcpfd == -1) && | |
788 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
789 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
790 | { | |
791 | close(last_server->tcpfd); | |
792 | last_server->tcpfd = -1; | |
793 | } | |
794 | ||
795 | if (last_server->tcpfd == -1) | |
796 | continue; | |
797 | ||
798 | c1 = size >> 8; | |
799 | c2 = size; | |
800 | ||
801 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
802 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
803 | !read_write(last_server->tcpfd, packet, size, 0) || | |
804 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
805 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
806 | { | |
807 | close(last_server->tcpfd); | |
808 | last_server->tcpfd = -1; | |
809 | continue; | |
810 | } | |
811 | ||
812 | m = (c1 << 8) | c2; | |
813 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
814 | return packet; | |
815 | ||
816 | if (!gotname) | |
3be34541 | 817 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 818 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 819 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 820 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
821 | #ifdef HAVE_IPV6 |
822 | else | |
3be34541 | 823 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 824 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
825 | #endif |
826 | ||
827 | /* There's no point in updating the cache, since this process will exit and | |
828 | lose the information after one query. We make this call for the alias and | |
829 | bogus-nxdomain side-effects. */ | |
0a852541 | 830 | m = process_reply(daemon, header, now, crc, last_server, (unsigned int)m); |
feba5c1d SK |
831 | |
832 | break; | |
833 | } | |
834 | } | |
835 | ||
836 | /* In case of local answer or no connections made. */ | |
837 | if (m == 0) | |
3be34541 | 838 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
839 | } |
840 | ||
841 | c1 = m>>8; | |
842 | c2 = m; | |
843 | if (!read_write(confd, &c1, 1, 0) || | |
844 | !read_write(confd, &c2, 1, 0) || | |
845 | !read_write(confd, packet, m, 0)) | |
846 | return packet; | |
847 | } | |
848 | } | |
849 | ||
9e4abcb5 SK |
850 | static struct frec *get_new_frec(time_t now) |
851 | { | |
852 | struct frec *f = frec_list, *oldest = NULL; | |
853 | time_t oldtime = now; | |
854 | int count = 0; | |
855 | static time_t warntime = 0; | |
856 | ||
857 | while (f) | |
858 | { | |
859 | if (f->new_id == 0) | |
860 | { | |
861 | f->time = now; | |
862 | return f; | |
863 | } | |
864 | ||
865 | if (difftime(f->time, oldtime) <= 0) | |
866 | { | |
867 | oldtime = f->time; | |
868 | oldest = f; | |
869 | } | |
870 | ||
871 | count++; | |
872 | f = f->next; | |
873 | } | |
874 | ||
875 | /* can't find empty one, use oldest if there is one | |
876 | and it's older than timeout */ | |
877 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
878 | { | |
879 | oldest->time = now; | |
880 | return oldest; | |
881 | } | |
882 | ||
883 | if (count > FTABSIZ) | |
884 | { /* limit logging rate so syslog isn't DOSed either */ | |
885 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
886 | { | |
887 | warntime = now; | |
b8187c80 | 888 | syslog(LOG_WARNING, _("forwarding table overflow: check for server loops.")); |
9e4abcb5 SK |
889 | } |
890 | return NULL; | |
891 | } | |
892 | ||
893 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
894 | { | |
895 | f->next = frec_list; | |
896 | f->time = now; | |
5e9e0efb | 897 | f->new_id = 0; |
9e4abcb5 SK |
898 | frec_list = f; |
899 | } | |
900 | return f; /* OK if malloc fails and this is NULL */ | |
901 | } | |
902 | ||
903 | static struct frec *lookup_frec(unsigned short id) | |
904 | { | |
905 | struct frec *f; | |
906 | ||
907 | for(f = frec_list; f; f = f->next) | |
908 | if (f->new_id == id) | |
909 | return f; | |
910 | ||
911 | return NULL; | |
912 | } | |
913 | ||
914 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
915 | union mysockaddr *addr, |
916 | unsigned int crc) | |
9e4abcb5 | 917 | { |
feba5c1d SK |
918 | struct frec *f; |
919 | ||
9e4abcb5 SK |
920 | for(f = frec_list; f; f = f->next) |
921 | if (f->new_id && | |
922 | f->orig_id == id && | |
fd9fa481 | 923 | f->crc == crc && |
9e4abcb5 SK |
924 | sockaddr_isequal(&f->source, addr)) |
925 | return f; | |
926 | ||
927 | return NULL; | |
928 | } | |
929 | ||
930 | ||
931 | /* return unique random ids between 1 and 65535 */ | |
932 | static unsigned short get_id(void) | |
933 | { | |
934 | unsigned short ret = 0; | |
935 | ||
936 | while (ret == 0) | |
937 | { | |
938 | ret = rand16(); | |
939 | ||
940 | /* scrap ids already in use */ | |
941 | if ((ret != 0) && lookup_frec(ret)) | |
942 | ret = 0; | |
943 | } | |
944 | ||
945 | return ret; | |
946 | } | |
947 | ||
948 | ||
949 | ||
950 | ||
951 |