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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 |
3d8df260 | 93 | #ifdef HAVE_IPV |
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); | |
163 | if (namelen >= domainlen && | |
164 | hostname_isequal(qdomain + namelen - domainlen, serv->domain) && | |
165 | domainlen >= matchlen) | |
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, | |
213 | HEADER *header, int plen, time_t now) | |
9e4abcb5 SK |
214 | { |
215 | struct frec *forward; | |
216 | char *domain = NULL; | |
0a852541 | 217 | int type = 0; |
9e4abcb5 | 218 | struct all_addr *addrp = NULL; |
3d8df260 | 219 | unsigned int crc = questions_crc(header, (unsigned int)plen, daemon->namebuff); |
9e4abcb5 | 220 | unsigned short flags = 0; |
3be34541 | 221 | unsigned short gotname = extract_request(header, (unsigned int)plen, daemon->namebuff, NULL); |
de37951c | 222 | struct server *start = NULL; |
3d8df260 SK |
223 | |
224 | /* may be no servers available. */ | |
225 | if (!daemon->servers) | |
9e4abcb5 | 226 | forward = NULL; |
fd9fa481 | 227 | else if ((forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 228 | { |
de37951c | 229 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 230 | domain = forward->sentto->domain; |
3be34541 | 231 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 232 | { |
0a852541 | 233 | forward->forwardall = 1; |
3be34541 | 234 | daemon->last_server = NULL; |
de37951c | 235 | } |
9e4abcb5 | 236 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 237 | if (!(start = forward->sentto->next)) |
3be34541 | 238 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
239 | header->id = htons(forward->new_id); |
240 | } | |
241 | else | |
242 | { | |
243 | if (gotname) | |
36717eee | 244 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 245 | |
feba5c1d SK |
246 | if (!flags && !(forward = get_new_frec(now))) |
247 | /* table full - server failure. */ | |
248 | flags = F_NEG; | |
9e4abcb5 SK |
249 | |
250 | if (forward) | |
251 | { | |
0a852541 SK |
252 | forward->source = *udpaddr; |
253 | forward->dest = *dst_addr; | |
254 | forward->iface = dst_iface; | |
255 | forward->new_id = get_id(); | |
256 | forward->fd = udpfd; | |
257 | forward->orig_id = ntohs(header->id); | |
258 | forward->crc = crc; | |
259 | forward->forwardall = 0; | |
260 | header->id = htons(forward->new_id); | |
261 | ||
9e4abcb5 SK |
262 | /* In strict_order mode, or when using domain specific servers |
263 | always try servers in the order specified in resolv.conf, | |
264 | otherwise, use the one last known to work. */ | |
265 | ||
3be34541 SK |
266 | if (type != 0 || (daemon->options & OPT_ORDER)) |
267 | start = daemon->servers; | |
268 | else if (!(start = daemon->last_server)) | |
de37951c | 269 | { |
3be34541 | 270 | start = daemon->servers; |
0a852541 | 271 | forward->forwardall = 1; |
de37951c | 272 | } |
9e4abcb5 SK |
273 | } |
274 | } | |
feba5c1d | 275 | |
9e4abcb5 SK |
276 | /* check for send errors here (no route to host) |
277 | if we fail to send to all nameservers, send back an error | |
278 | packet straight away (helps modem users when offline) */ | |
279 | ||
280 | if (!flags && forward) | |
281 | { | |
de37951c SK |
282 | struct server *firstsentto = start; |
283 | int forwarded = 0; | |
284 | ||
9e4abcb5 SK |
285 | while (1) |
286 | { | |
9e4abcb5 SK |
287 | /* only send to servers dealing with our domain. |
288 | domain may be NULL, in which case server->domain | |
289 | must be NULL also. */ | |
290 | ||
de37951c | 291 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
292 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
293 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 294 | { |
fd9fa481 | 295 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 296 | &start->addr.sa, |
fd9fa481 SK |
297 | sa_len(&start->addr)) == -1) |
298 | { | |
299 | if (retry_send()) | |
300 | continue; | |
301 | } | |
302 | else | |
9e4abcb5 | 303 | { |
de37951c | 304 | if (!gotname) |
3be34541 | 305 | strcpy(daemon->namebuff, "query"); |
de37951c | 306 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 307 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
308 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
309 | NULL, 0); | |
de37951c SK |
310 | #ifdef HAVE_IPV6 |
311 | else | |
3be34541 | 312 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
313 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
314 | NULL, 0); | |
de37951c SK |
315 | #endif |
316 | forwarded = 1; | |
317 | forward->sentto = start; | |
0a852541 | 318 | if (!forward->forwardall) |
de37951c | 319 | break; |
0a852541 | 320 | forward->forwardall++; |
9e4abcb5 SK |
321 | } |
322 | } | |
323 | ||
de37951c | 324 | if (!(start = start->next)) |
3be34541 | 325 | start = daemon->servers; |
9e4abcb5 | 326 | |
de37951c | 327 | if (start == firstsentto) |
9e4abcb5 SK |
328 | break; |
329 | } | |
330 | ||
de37951c | 331 | if (forwarded) |
3be34541 | 332 | return; |
de37951c | 333 | |
9e4abcb5 SK |
334 | /* could not send on, prepare to return */ |
335 | header->id = htons(forward->orig_id); | |
336 | forward->new_id = 0; /* cancel */ | |
337 | } | |
338 | ||
339 | /* could not send on, return empty answer or address if known for whole domain */ | |
3be34541 SK |
340 | plen = setup_reply(header, (unsigned int)plen, addrp, flags, daemon->local_ttl); |
341 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
44a2a316 | 342 | |
3be34541 | 343 | return; |
9e4abcb5 SK |
344 | } |
345 | ||
3be34541 | 346 | static int process_reply(struct daemon *daemon, HEADER *header, time_t now, |
0a852541 | 347 | unsigned int query_crc, struct server *server, unsigned int n) |
feba5c1d | 348 | { |
36717eee | 349 | unsigned char *pheader, *sizep; |
fd9fa481 | 350 | unsigned int plen, munged = 0; |
feba5c1d SK |
351 | |
352 | /* If upstream is advertising a larger UDP packet size | |
353 | than we allow, trim it so that we don't get overlarge | |
354 | requests for the client. */ | |
355 | ||
36717eee | 356 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
357 | { |
358 | unsigned short udpsz; | |
36717eee | 359 | unsigned char *psave = sizep; |
feba5c1d | 360 | |
36717eee | 361 | GETSHORT(udpsz, sizep); |
3be34541 SK |
362 | if (udpsz > daemon->edns_pktsz) |
363 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
364 | } |
365 | ||
0a852541 SK |
366 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
367 | return n; | |
368 | ||
feba5c1d | 369 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
370 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
371 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 372 | { |
3d8df260 SK |
373 | prettyprint_addr(&server->addr, daemon->namebuff); |
374 | syslog(LOG_WARNING, "nameserver %s refused to do a recursive query", daemon->namebuff); | |
0a852541 SK |
375 | if (!(daemon->options & OPT_LOG)) |
376 | server->flags |= SERV_WARNED_RECURSIVE; | |
377 | } | |
378 | ||
fd9fa481 SK |
379 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
380 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 381 | { |
fd9fa481 SK |
382 | munged = 1; |
383 | header->rcode = NXDOMAIN; | |
384 | header->aa = 0; | |
36717eee | 385 | } |
fd9fa481 | 386 | else |
36717eee | 387 | { |
fd9fa481 SK |
388 | if (header->rcode == NXDOMAIN && |
389 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 390 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
391 | { |
392 | /* if we forwarded a query for a locally known name (because it was for | |
393 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
394 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
395 | munged = 1; |
396 | header->aa = 1; | |
397 | header->rcode = NOERROR; | |
feba5c1d | 398 | } |
fd9fa481 | 399 | |
0a852541 SK |
400 | /* If the crc of the question section doesn't match the crc we sent, then |
401 | someone might be attempting to insert bogus values into the cache by | |
402 | sending replies containing questions and bogus answers. */ | |
403 | if (query_crc == questions_crc(header, n, daemon->namebuff)) | |
404 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 405 | } |
fd9fa481 SK |
406 | |
407 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
408 | nameserver info. */ | |
409 | ||
410 | if (munged) | |
411 | { | |
412 | header->ancount = htons(0); | |
413 | header->nscount = htons(0); | |
414 | header->arcount = htons(0); | |
415 | } | |
416 | ||
36717eee SK |
417 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
418 | sections of the packet. Find the new length here and put back pseudoheader | |
419 | if it was removed. */ | |
420 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
421 | } |
422 | ||
3be34541 SK |
423 | /* sets new last_server */ |
424 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
425 | { |
426 | /* packet from peer server, extract data for cache, and send to | |
427 | original requester */ | |
428 | struct frec *forward; | |
429 | HEADER *header; | |
de37951c SK |
430 | union mysockaddr serveraddr; |
431 | socklen_t addrlen = sizeof(serveraddr); | |
3be34541 | 432 | int n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
de37951c SK |
433 | |
434 | /* Determine the address of the server replying so that we can mark that as good */ | |
435 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
436 | #ifdef HAVE_IPV6 | |
437 | if (serveraddr.sa.sa_family == AF_INET6) | |
438 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
439 | #endif | |
9e4abcb5 | 440 | |
3be34541 | 441 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
442 | forward = lookup_frec(ntohs(header->id)); |
443 | ||
444 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 445 | { |
0a852541 SK |
446 | struct server *server = forward->sentto; |
447 | ||
448 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
449 | { | |
450 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
451 | server = NULL; | |
452 | else | |
453 | { | |
454 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
455 | struct server *last_server; | |
456 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
457 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
458 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
459 | { | |
460 | server = last_server; | |
461 | break; | |
462 | } | |
463 | } | |
464 | daemon->last_server = server; | |
465 | } | |
466 | ||
467 | if ((n = process_reply(daemon, header, now, forward->crc, server, (unsigned int)n))) | |
3be34541 SK |
468 | { |
469 | header->id = htons(forward->orig_id); | |
fd9fa481 | 470 | header->ra = 1; /* recursion if available */ |
26128d27 | 471 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, n, |
3be34541 | 472 | &forward->source, &forward->dest, forward->iface); |
3be34541 | 473 | } |
0a852541 SK |
474 | |
475 | /* If the answer is an error, keep the forward record in place in case | |
476 | we get a good reply from another server. Kill it when we've | |
477 | had replies from all to avoid filling the forwarding table when | |
478 | everything is broken */ | |
479 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
480 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
481 | forward->new_id = 0; /* cancel */ | |
9e4abcb5 | 482 | } |
9e4abcb5 | 483 | } |
44a2a316 | 484 | |
3be34541 | 485 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 486 | { |
3be34541 | 487 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 488 | union mysockaddr source_addr; |
c1bb8504 | 489 | unsigned short type; |
44a2a316 SK |
490 | struct iname *tmp; |
491 | struct all_addr dst_addr; | |
f6b7dc47 | 492 | struct in_addr netmask, dst_addr_4; |
8a911ccc | 493 | int m, n, if_index = 0; |
44a2a316 SK |
494 | struct iovec iov[1]; |
495 | struct msghdr msg; | |
496 | struct cmsghdr *cmptr; | |
44a2a316 SK |
497 | union { |
498 | struct cmsghdr align; /* this ensures alignment */ | |
499 | #ifdef HAVE_IPV6 | |
500 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
501 | #endif | |
502 | #if defined(IP_PKTINFO) | |
503 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
504 | #elif defined(IP_RECVDSTADDR) | |
505 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
506 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
507 | #endif | |
508 | } control_u; | |
509 | ||
f6b7dc47 SK |
510 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
511 | { | |
512 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
513 | netmask = listen->iface->netmask; | |
514 | } | |
515 | else | |
3d8df260 SK |
516 | { |
517 | dst_addr_4.s_addr = 0; | |
518 | netmask.s_addr = 0; | |
519 | } | |
f6b7dc47 | 520 | |
3be34541 SK |
521 | iov[0].iov_base = daemon->packet; |
522 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
523 | |
524 | msg.msg_control = control_u.control; | |
525 | msg.msg_controllen = sizeof(control_u); | |
526 | msg.msg_flags = 0; | |
527 | msg.msg_name = &source_addr; | |
528 | msg.msg_namelen = sizeof(source_addr); | |
529 | msg.msg_iov = iov; | |
530 | msg.msg_iovlen = 1; | |
531 | ||
de37951c | 532 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 533 | return; |
44a2a316 | 534 | |
26128d27 SK |
535 | if (n < (int)sizeof(HEADER) || header->qr) |
536 | return; | |
537 | ||
44a2a316 SK |
538 | source_addr.sa.sa_family = listen->family; |
539 | #ifdef HAVE_IPV6 | |
540 | if (listen->family == AF_INET6) | |
26128d27 | 541 | source_addr.in6.sin6_flowinfo = htonl(0); |
44a2a316 SK |
542 | #endif |
543 | ||
26128d27 SK |
544 | if (!(daemon->options & OPT_NOWILD)) |
545 | { | |
546 | struct ifreq ifr; | |
547 | ||
548 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
549 | return; | |
44a2a316 SK |
550 | |
551 | #if defined(IP_PKTINFO) | |
26128d27 SK |
552 | if (listen->family == AF_INET) |
553 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
554 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
555 | { | |
f6b7dc47 | 556 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
557 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
558 | } | |
559 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
560 | if (listen->family == AF_INET) | |
44a2a316 | 561 | { |
26128d27 SK |
562 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
563 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 564 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
565 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
566 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 567 | } |
44a2a316 | 568 | #endif |
26128d27 | 569 | |
44a2a316 | 570 | #ifdef HAVE_IPV6 |
26128d27 SK |
571 | if (listen->family == AF_INET6) |
572 | { | |
573 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
574 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
575 | { | |
576 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
577 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
578 | } | |
579 | } | |
44a2a316 | 580 | #endif |
26128d27 SK |
581 | |
582 | /* enforce available interface configuration */ | |
583 | ||
8a911ccc | 584 | if (if_index == 0) |
3be34541 | 585 | return; |
44a2a316 | 586 | |
f6b7dc47 | 587 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
588 | { |
589 | #ifdef SIOCGIFNAME | |
590 | ifr.ifr_ifindex = if_index; | |
591 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 592 | return; |
8a911ccc SK |
593 | #else |
594 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 595 | return; |
8a911ccc | 596 | #endif |
f6b7dc47 SK |
597 | |
598 | if (listen->family == AF_INET && | |
599 | (daemon->options & OPT_LOCALISE) && | |
600 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
601 | return; | |
602 | ||
603 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
604 | } |
605 | ||
3be34541 | 606 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 607 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 608 | return; |
9e4abcb5 | 609 | |
3be34541 | 610 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 611 | { |
3be34541 | 612 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 613 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
614 | break; |
615 | if (!tmp) | |
3be34541 | 616 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
617 | if (tmp->addr.sa.sa_family == listen->family) |
618 | { | |
619 | if (tmp->addr.sa.sa_family == AF_INET && | |
620 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
621 | break; | |
622 | #ifdef HAVE_IPV6 | |
623 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
624 | memcmp(&tmp->addr.in6.sin6_addr, | |
625 | &dst_addr.addr.addr6, | |
626 | sizeof(struct in6_addr)) == 0) | |
627 | break; | |
628 | #endif | |
629 | } | |
630 | if (!tmp) | |
3be34541 | 631 | return; |
44a2a316 SK |
632 | } |
633 | } | |
634 | ||
3be34541 | 635 | if (extract_request(header, (unsigned int)n, daemon->namebuff, &type)) |
44a2a316 SK |
636 | { |
637 | if (listen->family == AF_INET) | |
3be34541 | 638 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 639 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
640 | #ifdef HAVE_IPV6 |
641 | else | |
3be34541 | 642 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 643 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
644 | #endif |
645 | } | |
646 | ||
f6b7dc47 SK |
647 | m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n, daemon, |
648 | dst_addr_4, netmask, now); | |
44a2a316 | 649 | if (m >= 1) |
3be34541 | 650 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 651 | else |
3be34541 SK |
652 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
653 | header, n, now); | |
44a2a316 SK |
654 | } |
655 | ||
3d8df260 | 656 | static int read_write(int fd, unsigned char *packet, int size, int rw) |
feba5c1d SK |
657 | { |
658 | int n, done; | |
659 | ||
660 | for (done = 0; done < size; done += n) | |
661 | { | |
662 | retry: | |
663 | if (rw) | |
664 | n = read(fd, &packet[done], (size_t)(size - done)); | |
665 | else | |
666 | n = write(fd, &packet[done], (size_t)(size - done)); | |
667 | ||
668 | if (n == 0) | |
669 | return 0; | |
670 | else if (n == -1) | |
671 | { | |
fd9fa481 | 672 | if (retry_send()) |
feba5c1d | 673 | goto retry; |
feba5c1d SK |
674 | else |
675 | return 0; | |
676 | } | |
677 | } | |
678 | return 1; | |
679 | } | |
680 | ||
681 | /* The daemon forks before calling this: it should deal with one connection, | |
682 | blocking as neccessary, and then return. Note, need to be a bit careful | |
683 | about resources for debug mode, when the fork is suppressed: that's | |
684 | done by the caller. */ | |
3d8df260 SK |
685 | unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, |
686 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d SK |
687 | { |
688 | int size = 0, m; | |
c1bb8504 | 689 | unsigned short qtype, gotname; |
feba5c1d SK |
690 | unsigned char c1, c2; |
691 | /* Max TCP packet + slop */ | |
3d8df260 | 692 | unsigned char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 693 | HEADER *header; |
3be34541 SK |
694 | struct server *last_server; |
695 | ||
feba5c1d SK |
696 | while (1) |
697 | { | |
698 | if (!packet || | |
699 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
700 | !(size = c1 << 8 | c2) || | |
701 | !read_write(confd, packet, size, 1)) | |
702 | return packet; | |
703 | ||
704 | if (size < (int)sizeof(HEADER)) | |
705 | continue; | |
706 | ||
707 | header = (HEADER *)packet; | |
708 | ||
3be34541 | 709 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
710 | { |
711 | union mysockaddr peer_addr; | |
712 | socklen_t peer_len = sizeof(union mysockaddr); | |
713 | ||
714 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
715 | { | |
716 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 717 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 718 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
719 | #ifdef HAVE_IPV6 |
720 | else | |
3be34541 | 721 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 722 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
723 | #endif |
724 | } | |
725 | } | |
726 | ||
727 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
728 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
729 | local_addr, netmask, now); | |
feba5c1d SK |
730 | |
731 | if (m == 0) | |
732 | { | |
733 | unsigned short flags = 0; | |
feba5c1d SK |
734 | struct all_addr *addrp = NULL; |
735 | int type = 0; | |
736 | char *domain = NULL; | |
737 | ||
738 | if (gotname) | |
36717eee | 739 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 740 | |
3be34541 SK |
741 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
742 | last_server = daemon->servers; | |
743 | else | |
744 | last_server = daemon->last_server; | |
feba5c1d SK |
745 | |
746 | if (!flags && last_server) | |
747 | { | |
748 | struct server *firstsendto = NULL; | |
0a852541 SK |
749 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
750 | ||
feba5c1d SK |
751 | /* Loop round available servers until we succeed in connecting to one. |
752 | Note that this code subtley ensures that consecutive queries on this connection | |
753 | which can go to the same server, do so. */ | |
754 | while (1) | |
755 | { | |
756 | if (!firstsendto) | |
757 | firstsendto = last_server; | |
758 | else | |
759 | { | |
760 | if (!(last_server = last_server->next)) | |
3be34541 | 761 | last_server = daemon->servers; |
feba5c1d SK |
762 | |
763 | if (last_server == firstsendto) | |
764 | break; | |
765 | } | |
766 | ||
767 | /* server for wrong domain */ | |
768 | if (type != (last_server->flags & SERV_TYPE) || | |
769 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
770 | continue; | |
771 | ||
772 | if ((last_server->tcpfd == -1) && | |
773 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
774 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
775 | { | |
776 | close(last_server->tcpfd); | |
777 | last_server->tcpfd = -1; | |
778 | } | |
779 | ||
780 | if (last_server->tcpfd == -1) | |
781 | continue; | |
782 | ||
783 | c1 = size >> 8; | |
784 | c2 = size; | |
785 | ||
786 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
787 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
788 | !read_write(last_server->tcpfd, packet, size, 0) || | |
789 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
790 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
791 | { | |
792 | close(last_server->tcpfd); | |
793 | last_server->tcpfd = -1; | |
794 | continue; | |
795 | } | |
796 | ||
797 | m = (c1 << 8) | c2; | |
798 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
799 | return packet; | |
800 | ||
801 | if (!gotname) | |
3be34541 | 802 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 803 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 804 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 805 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
806 | #ifdef HAVE_IPV6 |
807 | else | |
3be34541 | 808 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 809 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
810 | #endif |
811 | ||
812 | /* There's no point in updating the cache, since this process will exit and | |
813 | lose the information after one query. We make this call for the alias and | |
814 | bogus-nxdomain side-effects. */ | |
0a852541 | 815 | m = process_reply(daemon, header, now, crc, last_server, (unsigned int)m); |
feba5c1d SK |
816 | |
817 | break; | |
818 | } | |
819 | } | |
820 | ||
821 | /* In case of local answer or no connections made. */ | |
822 | if (m == 0) | |
3be34541 | 823 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
824 | } |
825 | ||
826 | c1 = m>>8; | |
827 | c2 = m; | |
828 | if (!read_write(confd, &c1, 1, 0) || | |
829 | !read_write(confd, &c2, 1, 0) || | |
830 | !read_write(confd, packet, m, 0)) | |
831 | return packet; | |
832 | } | |
833 | } | |
834 | ||
9e4abcb5 SK |
835 | static struct frec *get_new_frec(time_t now) |
836 | { | |
837 | struct frec *f = frec_list, *oldest = NULL; | |
838 | time_t oldtime = now; | |
839 | int count = 0; | |
840 | static time_t warntime = 0; | |
841 | ||
842 | while (f) | |
843 | { | |
844 | if (f->new_id == 0) | |
845 | { | |
846 | f->time = now; | |
847 | return f; | |
848 | } | |
849 | ||
850 | if (difftime(f->time, oldtime) <= 0) | |
851 | { | |
852 | oldtime = f->time; | |
853 | oldest = f; | |
854 | } | |
855 | ||
856 | count++; | |
857 | f = f->next; | |
858 | } | |
859 | ||
860 | /* can't find empty one, use oldest if there is one | |
861 | and it's older than timeout */ | |
862 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
863 | { | |
864 | oldest->time = now; | |
865 | return oldest; | |
866 | } | |
867 | ||
868 | if (count > FTABSIZ) | |
869 | { /* limit logging rate so syslog isn't DOSed either */ | |
870 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
871 | { | |
872 | warntime = now; | |
873 | syslog(LOG_WARNING, "forwarding table overflow: check for server loops."); | |
874 | } | |
875 | return NULL; | |
876 | } | |
877 | ||
878 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
879 | { | |
880 | f->next = frec_list; | |
881 | f->time = now; | |
882 | frec_list = f; | |
883 | } | |
884 | return f; /* OK if malloc fails and this is NULL */ | |
885 | } | |
886 | ||
887 | static struct frec *lookup_frec(unsigned short id) | |
888 | { | |
889 | struct frec *f; | |
890 | ||
891 | for(f = frec_list; f; f = f->next) | |
892 | if (f->new_id == id) | |
893 | return f; | |
894 | ||
895 | return NULL; | |
896 | } | |
897 | ||
898 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
899 | union mysockaddr *addr, |
900 | unsigned int crc) | |
9e4abcb5 | 901 | { |
feba5c1d SK |
902 | struct frec *f; |
903 | ||
9e4abcb5 SK |
904 | for(f = frec_list; f; f = f->next) |
905 | if (f->new_id && | |
906 | f->orig_id == id && | |
fd9fa481 | 907 | f->crc == crc && |
9e4abcb5 SK |
908 | sockaddr_isequal(&f->source, addr)) |
909 | return f; | |
910 | ||
911 | return NULL; | |
912 | } | |
913 | ||
914 | ||
915 | /* return unique random ids between 1 and 65535 */ | |
916 | static unsigned short get_id(void) | |
917 | { | |
918 | unsigned short ret = 0; | |
919 | ||
920 | while (ret == 0) | |
921 | { | |
922 | ret = rand16(); | |
923 | ||
924 | /* scrap ids already in use */ | |
925 | if ((ret != 0) && lookup_frec(ret)) | |
926 | ret = 0; | |
927 | } | |
928 | ||
929 | return ret; | |
930 | } | |
931 | ||
932 | ||
933 | ||
934 | ||
935 |