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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 | ||
13 | /* Author's email: simon@thekelleys.org.uk */ | |
14 | ||
15 | #include "dnsmasq.h" | |
16 | ||
17 | static struct frec *frec_list; | |
18 | ||
19 | static struct frec *get_new_frec(time_t now); | |
20 | static struct frec *lookup_frec(unsigned short id); | |
21 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
22 | union mysockaddr *addr, |
23 | unsigned int crc); | |
9e4abcb5 SK |
24 | static unsigned short get_id(void); |
25 | ||
26 | /* May be called more than once. */ | |
27 | void forward_init(int first) | |
28 | { | |
29 | struct frec *f; | |
feba5c1d | 30 | |
9e4abcb5 SK |
31 | if (first) |
32 | frec_list = NULL; | |
33 | for (f = frec_list; f; f = f->next) | |
34 | f->new_id = 0; | |
35 | } | |
36 | ||
44a2a316 SK |
37 | /* Send a UDP packet with it's source address set as "source" |
38 | unless nowild is true, when we just send it with the kernel default */ | |
39 | static void send_from(int fd, int nowild, char *packet, int len, | |
dfa666f2 SK |
40 | union mysockaddr *to, struct all_addr *source, |
41 | unsigned int iface) | |
9e4abcb5 | 42 | { |
44a2a316 SK |
43 | struct msghdr msg; |
44 | struct iovec iov[1]; | |
44a2a316 SK |
45 | union { |
46 | struct cmsghdr align; /* this ensures alignment */ | |
47 | #if defined(IP_PKTINFO) | |
48 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
49 | #elif defined(IP_SENDSRCADDR) | |
50 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
51 | #endif | |
52 | #ifdef HAVE_IPV6 | |
53 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
54 | #endif | |
55 | } control_u; | |
feba5c1d | 56 | |
44a2a316 SK |
57 | iov[0].iov_base = packet; |
58 | iov[0].iov_len = len; | |
59 | ||
feba5c1d SK |
60 | msg.msg_control = NULL; |
61 | msg.msg_controllen = 0; | |
44a2a316 SK |
62 | msg.msg_flags = 0; |
63 | msg.msg_name = to; | |
64 | msg.msg_namelen = sa_len(to); | |
65 | msg.msg_iov = iov; | |
66 | msg.msg_iovlen = 1; | |
feba5c1d | 67 | |
26128d27 | 68 | if (!nowild) |
44a2a316 | 69 | { |
26128d27 | 70 | struct cmsghdr *cmptr; |
feba5c1d SK |
71 | msg.msg_control = &control_u; |
72 | msg.msg_controllen = sizeof(control_u); | |
26128d27 SK |
73 | cmptr = CMSG_FIRSTHDR(&msg); |
74 | ||
75 | if (to->sa.sa_family == AF_INET) | |
76 | { | |
feba5c1d | 77 | #if defined(IP_PKTINFO) |
26128d27 SK |
78 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
79 | pkt->ipi_ifindex = 0; | |
80 | pkt->ipi_spec_dst = source->addr.addr4; | |
81 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
82 | cmptr->cmsg_level = SOL_IP; | |
83 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 84 | #elif defined(IP_SENDSRCADDR) |
26128d27 SK |
85 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
86 | *a = source->addr.addr4; | |
87 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
88 | cmptr->cmsg_level = IPPROTO_IP; | |
89 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 90 | #endif |
26128d27 | 91 | } |
26128d27 | 92 | else |
b8187c80 | 93 | #ifdef HAVE_IPV6 |
26128d27 SK |
94 | { |
95 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
96 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
97 | pkt->ipi6_addr = source->addr.addr6; | |
98 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
99 | cmptr->cmsg_type = IPV6_PKTINFO; | |
100 | cmptr->cmsg_level = IPV6_LEVEL; | |
101 | } | |
3d8df260 SK |
102 | #else |
103 | iface = 0; /* eliminate warning */ | |
44a2a316 | 104 | #endif |
26128d27 | 105 | } |
feba5c1d | 106 | |
fd9fa481 SK |
107 | retry: |
108 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 109 | { |
fd9fa481 SK |
110 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
111 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
112 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
113 | if (errno == EINVAL && msg.msg_controllen) | |
114 | { | |
115 | msg.msg_controllen = 0; | |
116 | goto retry; | |
117 | } | |
118 | if (retry_send()) | |
119 | goto retry; | |
feba5c1d | 120 | } |
9e4abcb5 | 121 | } |
44a2a316 | 122 | |
36717eee SK |
123 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
124 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
125 | |
126 | { | |
127 | /* If the query ends in the domain in one of our servers, set | |
128 | domain to point to that name. We find the largest match to allow both | |
129 | domain.org and sub.domain.org to exist. */ | |
130 | ||
131 | unsigned int namelen = strlen(qdomain); | |
132 | unsigned int matchlen = 0; | |
133 | struct server *serv; | |
134 | unsigned short flags = 0; | |
135 | ||
3be34541 | 136 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 137 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 138 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d SK |
139 | { |
140 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
141 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 142 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
143 | flags = F_NXDOMAIN; |
144 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
145 | { | |
146 | if (sflag & qtype) | |
147 | { | |
148 | flags = sflag; | |
149 | if (serv->addr.sa.sa_family == AF_INET) | |
150 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 151 | #ifdef HAVE_IPV6 |
36717eee SK |
152 | else |
153 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 154 | #endif |
36717eee SK |
155 | } |
156 | else if (!flags) | |
157 | flags = F_NOERR; | |
158 | } | |
feba5c1d SK |
159 | } |
160 | else if (serv->flags & SERV_HAS_DOMAIN) | |
161 | { | |
162 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 163 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 164 | if (namelen >= domainlen && |
b8187c80 SK |
165 | hostname_isequal(matchstart, serv->domain) && |
166 | domainlen >= matchlen && | |
167 | (namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) | |
feba5c1d SK |
168 | { |
169 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
170 | *type = SERV_HAS_DOMAIN; | |
171 | *domain = serv->domain; | |
172 | matchlen = domainlen; | |
feba5c1d | 173 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
174 | flags = F_NXDOMAIN; |
175 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 176 | { |
36717eee SK |
177 | if ((sflag | F_QUERY ) & qtype) |
178 | { | |
179 | flags = qtype; | |
180 | if (serv->addr.sa.sa_family == AF_INET) | |
181 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 182 | #ifdef HAVE_IPV6 |
36717eee SK |
183 | else |
184 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 185 | #endif |
36717eee SK |
186 | } |
187 | else if (!flags) | |
188 | flags = F_NOERR; | |
feba5c1d SK |
189 | } |
190 | } | |
191 | } | |
192 | ||
36717eee | 193 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
194 | { |
195 | if (flags & F_QUERY) | |
fd9fa481 | 196 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0, NULL, 0); |
feba5c1d | 197 | else |
fd9fa481 | 198 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0, NULL, 0); |
feba5c1d | 199 | } |
3d8df260 | 200 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
36717eee SK |
201 | flags = F_NXDOMAIN; |
202 | ||
f6b7dc47 | 203 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon)) |
c1bb8504 | 204 | flags = F_NOERR; |
feba5c1d | 205 | |
36717eee | 206 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
fd9fa481 | 207 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0, NULL, 0); |
feba5c1d SK |
208 | |
209 | return flags; | |
210 | } | |
44a2a316 | 211 | |
9e4abcb5 | 212 | /* returns new last_server */ |
3be34541 SK |
213 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
214 | struct all_addr *dst_addr, unsigned int dst_iface, | |
b8187c80 | 215 | HEADER *header, int plen, time_t now, struct frec *forward) |
9e4abcb5 | 216 | { |
9e4abcb5 | 217 | char *domain = NULL; |
0a852541 | 218 | int type = 0; |
9e4abcb5 | 219 | struct all_addr *addrp = NULL; |
3d8df260 | 220 | unsigned int crc = questions_crc(header, (unsigned int)plen, daemon->namebuff); |
9e4abcb5 | 221 | unsigned short flags = 0; |
3be34541 | 222 | unsigned short gotname = extract_request(header, (unsigned int)plen, daemon->namebuff, NULL); |
de37951c | 223 | struct server *start = NULL; |
3d8df260 SK |
224 | |
225 | /* may be no servers available. */ | |
226 | if (!daemon->servers) | |
9e4abcb5 | 227 | forward = NULL; |
b8187c80 | 228 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 229 | { |
de37951c | 230 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 231 | domain = forward->sentto->domain; |
3be34541 | 232 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 233 | { |
0a852541 | 234 | forward->forwardall = 1; |
3be34541 | 235 | daemon->last_server = NULL; |
de37951c | 236 | } |
9e4abcb5 | 237 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 238 | if (!(start = forward->sentto->next)) |
3be34541 | 239 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
240 | header->id = htons(forward->new_id); |
241 | } | |
242 | else | |
243 | { | |
244 | if (gotname) | |
36717eee | 245 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 246 | |
feba5c1d SK |
247 | if (!flags && !(forward = get_new_frec(now))) |
248 | /* table full - server failure. */ | |
249 | flags = F_NEG; | |
9e4abcb5 SK |
250 | |
251 | if (forward) | |
252 | { | |
0a852541 SK |
253 | forward->source = *udpaddr; |
254 | forward->dest = *dst_addr; | |
255 | forward->iface = dst_iface; | |
256 | forward->new_id = get_id(); | |
257 | forward->fd = udpfd; | |
258 | forward->orig_id = ntohs(header->id); | |
259 | forward->crc = crc; | |
260 | forward->forwardall = 0; | |
261 | header->id = htons(forward->new_id); | |
262 | ||
9e4abcb5 SK |
263 | /* In strict_order mode, or when using domain specific servers |
264 | always try servers in the order specified in resolv.conf, | |
265 | otherwise, use the one last known to work. */ | |
266 | ||
3be34541 SK |
267 | if (type != 0 || (daemon->options & OPT_ORDER)) |
268 | start = daemon->servers; | |
269 | else if (!(start = daemon->last_server)) | |
de37951c | 270 | { |
3be34541 | 271 | start = daemon->servers; |
0a852541 | 272 | forward->forwardall = 1; |
de37951c | 273 | } |
9e4abcb5 SK |
274 | } |
275 | } | |
feba5c1d | 276 | |
9e4abcb5 SK |
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 | { | |
de37951c SK |
283 | struct server *firstsentto = start; |
284 | int forwarded = 0; | |
285 | ||
9e4abcb5 SK |
286 | while (1) |
287 | { | |
9e4abcb5 SK |
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 | ||
de37951c | 292 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
293 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
294 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 295 | { |
fd9fa481 | 296 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 297 | &start->addr.sa, |
fd9fa481 SK |
298 | sa_len(&start->addr)) == -1) |
299 | { | |
300 | if (retry_send()) | |
301 | continue; | |
302 | } | |
303 | else | |
9e4abcb5 | 304 | { |
de37951c | 305 | if (!gotname) |
3be34541 | 306 | strcpy(daemon->namebuff, "query"); |
de37951c | 307 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 308 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
309 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
310 | NULL, 0); | |
de37951c SK |
311 | #ifdef HAVE_IPV6 |
312 | else | |
3be34541 | 313 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
314 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
315 | NULL, 0); | |
de37951c SK |
316 | #endif |
317 | forwarded = 1; | |
318 | forward->sentto = start; | |
0a852541 | 319 | if (!forward->forwardall) |
de37951c | 320 | break; |
0a852541 | 321 | forward->forwardall++; |
9e4abcb5 SK |
322 | } |
323 | } | |
324 | ||
de37951c | 325 | if (!(start = start->next)) |
3be34541 | 326 | start = daemon->servers; |
9e4abcb5 | 327 | |
de37951c | 328 | if (start == firstsentto) |
9e4abcb5 SK |
329 | break; |
330 | } | |
331 | ||
de37951c | 332 | if (forwarded) |
3be34541 | 333 | return; |
de37951c | 334 | |
9e4abcb5 SK |
335 | /* could not send on, prepare to return */ |
336 | header->id = htons(forward->orig_id); | |
337 | forward->new_id = 0; /* cancel */ | |
338 | } | |
339 | ||
340 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
341 | if (udpfd != -1) |
342 | { | |
343 | plen = setup_reply(header, (unsigned int)plen, addrp, flags, daemon->local_ttl); | |
344 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
345 | } | |
346 | ||
3be34541 | 347 | return; |
9e4abcb5 SK |
348 | } |
349 | ||
3be34541 | 350 | static int process_reply(struct daemon *daemon, HEADER *header, time_t now, |
0a852541 | 351 | unsigned int query_crc, struct server *server, unsigned int n) |
feba5c1d | 352 | { |
36717eee | 353 | unsigned char *pheader, *sizep; |
fd9fa481 | 354 | unsigned int plen, munged = 0; |
feba5c1d SK |
355 | |
356 | /* If upstream is advertising a larger UDP packet size | |
357 | than we allow, trim it so that we don't get overlarge | |
358 | requests for the client. */ | |
359 | ||
36717eee | 360 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
361 | { |
362 | unsigned short udpsz; | |
36717eee | 363 | unsigned char *psave = sizep; |
feba5c1d | 364 | |
36717eee | 365 | GETSHORT(udpsz, sizep); |
3be34541 SK |
366 | if (udpsz > daemon->edns_pktsz) |
367 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
368 | } |
369 | ||
0a852541 SK |
370 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
371 | return n; | |
372 | ||
feba5c1d | 373 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
374 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
375 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 376 | { |
3d8df260 | 377 | prettyprint_addr(&server->addr, daemon->namebuff); |
b8187c80 | 378 | syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
0a852541 SK |
379 | if (!(daemon->options & OPT_LOG)) |
380 | server->flags |= SERV_WARNED_RECURSIVE; | |
381 | } | |
382 | ||
fd9fa481 SK |
383 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
384 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 385 | { |
fd9fa481 SK |
386 | munged = 1; |
387 | header->rcode = NXDOMAIN; | |
388 | header->aa = 0; | |
36717eee | 389 | } |
fd9fa481 | 390 | else |
36717eee | 391 | { |
fd9fa481 SK |
392 | if (header->rcode == NXDOMAIN && |
393 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 394 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
395 | { |
396 | /* if we forwarded a query for a locally known name (because it was for | |
397 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
398 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
399 | munged = 1; |
400 | header->aa = 1; | |
401 | header->rcode = NOERROR; | |
feba5c1d | 402 | } |
fd9fa481 | 403 | |
0a852541 SK |
404 | /* If the crc of the question section doesn't match the crc we sent, then |
405 | someone might be attempting to insert bogus values into the cache by | |
406 | sending replies containing questions and bogus answers. */ | |
407 | if (query_crc == questions_crc(header, n, daemon->namebuff)) | |
408 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 409 | } |
fd9fa481 SK |
410 | |
411 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
412 | nameserver info. */ | |
413 | ||
414 | if (munged) | |
415 | { | |
416 | header->ancount = htons(0); | |
417 | header->nscount = htons(0); | |
418 | header->arcount = htons(0); | |
419 | } | |
420 | ||
36717eee SK |
421 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
422 | sections of the packet. Find the new length here and put back pseudoheader | |
423 | if it was removed. */ | |
424 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
425 | } |
426 | ||
3be34541 SK |
427 | /* sets new last_server */ |
428 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
429 | { |
430 | /* packet from peer server, extract data for cache, and send to | |
431 | original requester */ | |
432 | struct frec *forward; | |
433 | HEADER *header; | |
de37951c SK |
434 | union mysockaddr serveraddr; |
435 | socklen_t addrlen = sizeof(serveraddr); | |
3be34541 | 436 | int n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
de37951c SK |
437 | |
438 | /* Determine the address of the server replying so that we can mark that as good */ | |
439 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
440 | #ifdef HAVE_IPV6 | |
441 | if (serveraddr.sa.sa_family == AF_INET6) | |
442 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
443 | #endif | |
9e4abcb5 | 444 | |
3be34541 | 445 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
446 | forward = lookup_frec(ntohs(header->id)); |
447 | ||
448 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 449 | { |
0a852541 SK |
450 | struct server *server = forward->sentto; |
451 | ||
b8187c80 SK |
452 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && forward->forwardall == 0) |
453 | /* for broken servers, attempt to send to another one. */ | |
454 | { | |
455 | unsigned char *pheader; | |
456 | unsigned int plen; | |
457 | int nn; | |
458 | /* recreate query from reply */ | |
459 | pheader = find_pseudoheader(header, n, &plen, NULL); | |
460 | header->ancount = htons(0); | |
461 | header->nscount = htons(0); | |
462 | header->arcount = htons(0); | |
463 | if ((nn = resize_packet(header, n, pheader, plen))) | |
464 | { | |
465 | forward->forwardall = 1; | |
466 | header->qr = 0; | |
467 | header->tc = 0; | |
468 | forward_query(daemon, -1, NULL, NULL, 0, header, nn, now, forward); | |
469 | return; | |
470 | } | |
471 | } | |
472 | ||
0a852541 SK |
473 | if ((forward->sentto->flags & SERV_TYPE) == 0) |
474 | { | |
475 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
476 | server = NULL; | |
477 | else | |
b8187c80 SK |
478 | { |
479 | struct server *last_server; | |
480 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
481 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
482 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
483 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
484 | { | |
485 | server = last_server; | |
486 | break; | |
487 | } | |
488 | } | |
0a852541 SK |
489 | daemon->last_server = server; |
490 | } | |
b8187c80 | 491 | |
0a852541 SK |
492 | /* If the answer is an error, keep the forward record in place in case |
493 | we get a good reply from another server. Kill it when we've | |
494 | had replies from all to avoid filling the forwarding table when | |
495 | everything is broken */ | |
496 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
497 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
b8187c80 SK |
498 | { |
499 | if ((n = process_reply(daemon, header, now, forward->crc, server, (unsigned int)n))) | |
500 | { | |
501 | header->id = htons(forward->orig_id); | |
502 | header->ra = 1; /* recursion if available */ | |
503 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, n, | |
504 | &forward->source, &forward->dest, forward->iface); | |
505 | } | |
506 | forward->new_id = 0; /* cancel */ | |
507 | } | |
9e4abcb5 | 508 | } |
9e4abcb5 | 509 | } |
44a2a316 | 510 | |
3be34541 | 511 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 512 | { |
3be34541 | 513 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 514 | union mysockaddr source_addr; |
c1bb8504 | 515 | unsigned short type; |
44a2a316 SK |
516 | struct iname *tmp; |
517 | struct all_addr dst_addr; | |
f6b7dc47 | 518 | struct in_addr netmask, dst_addr_4; |
8a911ccc | 519 | int m, n, if_index = 0; |
44a2a316 SK |
520 | struct iovec iov[1]; |
521 | struct msghdr msg; | |
522 | struct cmsghdr *cmptr; | |
44a2a316 SK |
523 | union { |
524 | struct cmsghdr align; /* this ensures alignment */ | |
525 | #ifdef HAVE_IPV6 | |
526 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
527 | #endif | |
528 | #if defined(IP_PKTINFO) | |
529 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
530 | #elif defined(IP_RECVDSTADDR) | |
531 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
532 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
533 | #endif | |
534 | } control_u; | |
535 | ||
f6b7dc47 SK |
536 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
537 | { | |
538 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
539 | netmask = listen->iface->netmask; | |
540 | } | |
541 | else | |
3d8df260 SK |
542 | { |
543 | dst_addr_4.s_addr = 0; | |
544 | netmask.s_addr = 0; | |
545 | } | |
f6b7dc47 | 546 | |
3be34541 SK |
547 | iov[0].iov_base = daemon->packet; |
548 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
549 | |
550 | msg.msg_control = control_u.control; | |
551 | msg.msg_controllen = sizeof(control_u); | |
552 | msg.msg_flags = 0; | |
553 | msg.msg_name = &source_addr; | |
554 | msg.msg_namelen = sizeof(source_addr); | |
555 | msg.msg_iov = iov; | |
556 | msg.msg_iovlen = 1; | |
557 | ||
de37951c | 558 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 559 | return; |
44a2a316 | 560 | |
26128d27 SK |
561 | if (n < (int)sizeof(HEADER) || header->qr) |
562 | return; | |
563 | ||
44a2a316 SK |
564 | source_addr.sa.sa_family = listen->family; |
565 | #ifdef HAVE_IPV6 | |
566 | if (listen->family == AF_INET6) | |
26128d27 | 567 | source_addr.in6.sin6_flowinfo = htonl(0); |
44a2a316 SK |
568 | #endif |
569 | ||
26128d27 SK |
570 | if (!(daemon->options & OPT_NOWILD)) |
571 | { | |
572 | struct ifreq ifr; | |
573 | ||
574 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
575 | return; | |
44a2a316 SK |
576 | |
577 | #if defined(IP_PKTINFO) | |
26128d27 SK |
578 | if (listen->family == AF_INET) |
579 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
580 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
581 | { | |
f6b7dc47 | 582 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
583 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
584 | } | |
585 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
586 | if (listen->family == AF_INET) | |
44a2a316 | 587 | { |
26128d27 SK |
588 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
589 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 590 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
591 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
592 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 593 | } |
44a2a316 | 594 | #endif |
26128d27 | 595 | |
44a2a316 | 596 | #ifdef HAVE_IPV6 |
26128d27 SK |
597 | if (listen->family == AF_INET6) |
598 | { | |
599 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
600 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
601 | { | |
602 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
603 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
604 | } | |
605 | } | |
44a2a316 | 606 | #endif |
26128d27 SK |
607 | |
608 | /* enforce available interface configuration */ | |
609 | ||
8a911ccc | 610 | if (if_index == 0) |
3be34541 | 611 | return; |
44a2a316 | 612 | |
f6b7dc47 | 613 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
614 | { |
615 | #ifdef SIOCGIFNAME | |
616 | ifr.ifr_ifindex = if_index; | |
617 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 618 | return; |
8a911ccc SK |
619 | #else |
620 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 621 | return; |
8a911ccc | 622 | #endif |
f6b7dc47 SK |
623 | |
624 | if (listen->family == AF_INET && | |
625 | (daemon->options & OPT_LOCALISE) && | |
626 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
627 | return; | |
628 | ||
629 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
630 | } |
631 | ||
3be34541 | 632 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 633 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 634 | return; |
9e4abcb5 | 635 | |
3be34541 | 636 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 637 | { |
3be34541 | 638 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 639 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
640 | break; |
641 | if (!tmp) | |
3be34541 | 642 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
643 | if (tmp->addr.sa.sa_family == listen->family) |
644 | { | |
645 | if (tmp->addr.sa.sa_family == AF_INET && | |
646 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
647 | break; | |
648 | #ifdef HAVE_IPV6 | |
649 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
650 | memcmp(&tmp->addr.in6.sin6_addr, | |
651 | &dst_addr.addr.addr6, | |
652 | sizeof(struct in6_addr)) == 0) | |
653 | break; | |
654 | #endif | |
655 | } | |
656 | if (!tmp) | |
3be34541 | 657 | return; |
44a2a316 SK |
658 | } |
659 | } | |
660 | ||
3be34541 | 661 | if (extract_request(header, (unsigned int)n, daemon->namebuff, &type)) |
44a2a316 SK |
662 | { |
663 | if (listen->family == AF_INET) | |
3be34541 | 664 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 665 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
666 | #ifdef HAVE_IPV6 |
667 | else | |
3be34541 | 668 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 669 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
670 | #endif |
671 | } | |
672 | ||
f6b7dc47 SK |
673 | m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n, daemon, |
674 | dst_addr_4, netmask, now); | |
44a2a316 | 675 | if (m >= 1) |
3be34541 | 676 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 677 | else |
3be34541 | 678 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
b8187c80 | 679 | header, n, now, NULL); |
44a2a316 SK |
680 | } |
681 | ||
3d8df260 | 682 | static int read_write(int fd, unsigned char *packet, int size, int rw) |
feba5c1d SK |
683 | { |
684 | int n, done; | |
685 | ||
686 | for (done = 0; done < size; done += n) | |
687 | { | |
688 | retry: | |
689 | if (rw) | |
690 | n = read(fd, &packet[done], (size_t)(size - done)); | |
691 | else | |
692 | n = write(fd, &packet[done], (size_t)(size - done)); | |
693 | ||
694 | if (n == 0) | |
695 | return 0; | |
696 | else if (n == -1) | |
697 | { | |
fd9fa481 | 698 | if (retry_send()) |
feba5c1d | 699 | goto retry; |
feba5c1d SK |
700 | else |
701 | return 0; | |
702 | } | |
703 | } | |
704 | return 1; | |
705 | } | |
706 | ||
707 | /* The daemon forks before calling this: it should deal with one connection, | |
708 | blocking as neccessary, and then return. Note, need to be a bit careful | |
709 | about resources for debug mode, when the fork is suppressed: that's | |
710 | done by the caller. */ | |
3d8df260 SK |
711 | unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, |
712 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d SK |
713 | { |
714 | int size = 0, m; | |
c1bb8504 | 715 | unsigned short qtype, gotname; |
feba5c1d SK |
716 | unsigned char c1, c2; |
717 | /* Max TCP packet + slop */ | |
3d8df260 | 718 | unsigned char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 719 | HEADER *header; |
3be34541 SK |
720 | struct server *last_server; |
721 | ||
feba5c1d SK |
722 | while (1) |
723 | { | |
724 | if (!packet || | |
725 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
726 | !(size = c1 << 8 | c2) || | |
727 | !read_write(confd, packet, size, 1)) | |
728 | return packet; | |
729 | ||
730 | if (size < (int)sizeof(HEADER)) | |
731 | continue; | |
732 | ||
733 | header = (HEADER *)packet; | |
734 | ||
3be34541 | 735 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
736 | { |
737 | union mysockaddr peer_addr; | |
738 | socklen_t peer_len = sizeof(union mysockaddr); | |
739 | ||
740 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
741 | { | |
742 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 743 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 744 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
745 | #ifdef HAVE_IPV6 |
746 | else | |
3be34541 | 747 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 748 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
749 | #endif |
750 | } | |
751 | } | |
752 | ||
753 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
754 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
755 | local_addr, netmask, now); | |
feba5c1d SK |
756 | |
757 | if (m == 0) | |
758 | { | |
759 | unsigned short flags = 0; | |
feba5c1d SK |
760 | struct all_addr *addrp = NULL; |
761 | int type = 0; | |
762 | char *domain = NULL; | |
763 | ||
764 | if (gotname) | |
36717eee | 765 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 766 | |
3be34541 SK |
767 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
768 | last_server = daemon->servers; | |
769 | else | |
770 | last_server = daemon->last_server; | |
feba5c1d SK |
771 | |
772 | if (!flags && last_server) | |
773 | { | |
774 | struct server *firstsendto = NULL; | |
0a852541 SK |
775 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
776 | ||
feba5c1d SK |
777 | /* Loop round available servers until we succeed in connecting to one. |
778 | Note that this code subtley ensures that consecutive queries on this connection | |
779 | which can go to the same server, do so. */ | |
780 | while (1) | |
781 | { | |
782 | if (!firstsendto) | |
783 | firstsendto = last_server; | |
784 | else | |
785 | { | |
786 | if (!(last_server = last_server->next)) | |
3be34541 | 787 | last_server = daemon->servers; |
feba5c1d SK |
788 | |
789 | if (last_server == firstsendto) | |
790 | break; | |
791 | } | |
792 | ||
793 | /* server for wrong domain */ | |
794 | if (type != (last_server->flags & SERV_TYPE) || | |
795 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
796 | continue; | |
797 | ||
798 | if ((last_server->tcpfd == -1) && | |
799 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
800 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
801 | { | |
802 | close(last_server->tcpfd); | |
803 | last_server->tcpfd = -1; | |
804 | } | |
805 | ||
806 | if (last_server->tcpfd == -1) | |
807 | continue; | |
808 | ||
809 | c1 = size >> 8; | |
810 | c2 = size; | |
811 | ||
812 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
813 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
814 | !read_write(last_server->tcpfd, packet, size, 0) || | |
815 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
816 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
817 | { | |
818 | close(last_server->tcpfd); | |
819 | last_server->tcpfd = -1; | |
820 | continue; | |
821 | } | |
822 | ||
823 | m = (c1 << 8) | c2; | |
824 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
825 | return packet; | |
826 | ||
827 | if (!gotname) | |
3be34541 | 828 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 829 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 830 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 831 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
832 | #ifdef HAVE_IPV6 |
833 | else | |
3be34541 | 834 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 835 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
836 | #endif |
837 | ||
838 | /* There's no point in updating the cache, since this process will exit and | |
839 | lose the information after one query. We make this call for the alias and | |
840 | bogus-nxdomain side-effects. */ | |
0a852541 | 841 | m = process_reply(daemon, header, now, crc, last_server, (unsigned int)m); |
feba5c1d SK |
842 | |
843 | break; | |
844 | } | |
845 | } | |
846 | ||
847 | /* In case of local answer or no connections made. */ | |
848 | if (m == 0) | |
3be34541 | 849 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
850 | } |
851 | ||
852 | c1 = m>>8; | |
853 | c2 = m; | |
854 | if (!read_write(confd, &c1, 1, 0) || | |
855 | !read_write(confd, &c2, 1, 0) || | |
856 | !read_write(confd, packet, m, 0)) | |
857 | return packet; | |
858 | } | |
859 | } | |
860 | ||
9e4abcb5 SK |
861 | static struct frec *get_new_frec(time_t now) |
862 | { | |
863 | struct frec *f = frec_list, *oldest = NULL; | |
864 | time_t oldtime = now; | |
865 | int count = 0; | |
866 | static time_t warntime = 0; | |
867 | ||
868 | while (f) | |
869 | { | |
870 | if (f->new_id == 0) | |
871 | { | |
872 | f->time = now; | |
873 | return f; | |
874 | } | |
875 | ||
876 | if (difftime(f->time, oldtime) <= 0) | |
877 | { | |
878 | oldtime = f->time; | |
879 | oldest = f; | |
880 | } | |
881 | ||
882 | count++; | |
883 | f = f->next; | |
884 | } | |
885 | ||
886 | /* can't find empty one, use oldest if there is one | |
887 | and it's older than timeout */ | |
888 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
889 | { | |
890 | oldest->time = now; | |
891 | return oldest; | |
892 | } | |
893 | ||
894 | if (count > FTABSIZ) | |
895 | { /* limit logging rate so syslog isn't DOSed either */ | |
896 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
897 | { | |
898 | warntime = now; | |
b8187c80 | 899 | syslog(LOG_WARNING, _("forwarding table overflow: check for server loops.")); |
9e4abcb5 SK |
900 | } |
901 | return NULL; | |
902 | } | |
903 | ||
904 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
905 | { | |
906 | f->next = frec_list; | |
907 | f->time = now; | |
908 | frec_list = f; | |
909 | } | |
910 | return f; /* OK if malloc fails and this is NULL */ | |
911 | } | |
912 | ||
913 | static struct frec *lookup_frec(unsigned short id) | |
914 | { | |
915 | struct frec *f; | |
916 | ||
917 | for(f = frec_list; f; f = f->next) | |
918 | if (f->new_id == id) | |
919 | return f; | |
920 | ||
921 | return NULL; | |
922 | } | |
923 | ||
924 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
925 | union mysockaddr *addr, |
926 | unsigned int crc) | |
9e4abcb5 | 927 | { |
feba5c1d SK |
928 | struct frec *f; |
929 | ||
9e4abcb5 SK |
930 | for(f = frec_list; f; f = f->next) |
931 | if (f->new_id && | |
932 | f->orig_id == id && | |
fd9fa481 | 933 | f->crc == crc && |
9e4abcb5 SK |
934 | sockaddr_isequal(&f->source, addr)) |
935 | return f; | |
936 | ||
937 | return NULL; | |
938 | } | |
939 | ||
940 | ||
941 | /* return unique random ids between 1 and 65535 */ | |
942 | static unsigned short get_id(void) | |
943 | { | |
944 | unsigned short ret = 0; | |
945 | ||
946 | while (ret == 0) | |
947 | { | |
948 | ret = rand16(); | |
949 | ||
950 | /* scrap ids already in use */ | |
951 | if ((ret != 0) && lookup_frec(ret)) | |
952 | ret = 0; | |
953 | } | |
954 | ||
955 | return ret; | |
956 | } | |
957 | ||
958 | ||
959 | ||
960 | ||
961 |