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9e4abcb5 SK |
1 | /* dnsmasq is Copyright (c) 2000 - 2003 Simon Kelley |
2 | ||
3 | This program is free software; you can redistribute it and/or modify | |
4 | it under the terms of the GNU General Public License as published by | |
5 | the Free Software Foundation; version 2 dated June, 1991. | |
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, | |
22 | union mysockaddr *addr); | |
23 | static unsigned short get_id(void); | |
24 | ||
25 | /* May be called more than once. */ | |
26 | void forward_init(int first) | |
27 | { | |
28 | struct frec *f; | |
feba5c1d | 29 | |
9e4abcb5 SK |
30 | if (first) |
31 | frec_list = NULL; | |
32 | for (f = frec_list; f; f = f->next) | |
33 | f->new_id = 0; | |
34 | } | |
35 | ||
44a2a316 SK |
36 | /* Send a UDP packet with it's source address set as "source" |
37 | unless nowild is true, when we just send it with the kernel default */ | |
38 | static void send_from(int fd, int nowild, char *packet, int len, | |
dfa666f2 SK |
39 | union mysockaddr *to, struct all_addr *source, |
40 | unsigned int iface) | |
9e4abcb5 | 41 | { |
44a2a316 SK |
42 | struct msghdr msg; |
43 | struct iovec iov[1]; | |
44a2a316 SK |
44 | union { |
45 | struct cmsghdr align; /* this ensures alignment */ | |
46 | #if defined(IP_PKTINFO) | |
47 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
48 | #elif defined(IP_SENDSRCADDR) | |
49 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
50 | #endif | |
51 | #ifdef HAVE_IPV6 | |
52 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
53 | #endif | |
54 | } control_u; | |
feba5c1d | 55 | |
44a2a316 SK |
56 | iov[0].iov_base = packet; |
57 | iov[0].iov_len = len; | |
58 | ||
feba5c1d SK |
59 | msg.msg_control = NULL; |
60 | msg.msg_controllen = 0; | |
44a2a316 SK |
61 | msg.msg_flags = 0; |
62 | msg.msg_name = to; | |
63 | msg.msg_namelen = sa_len(to); | |
64 | msg.msg_iov = iov; | |
65 | msg.msg_iovlen = 1; | |
feba5c1d | 66 | |
44a2a316 SK |
67 | if (!nowild && to->sa.sa_family == AF_INET) |
68 | { | |
feba5c1d SK |
69 | msg.msg_control = &control_u; |
70 | msg.msg_controllen = sizeof(control_u); | |
71 | { | |
72 | struct cmsghdr *cmptr = CMSG_FIRSTHDR(&msg); | |
73 | #if defined(IP_PKTINFO) | |
74 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); | |
75 | pkt->ipi_ifindex = 0; | |
76 | pkt->ipi_spec_dst = source->addr.addr4; | |
77 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
78 | cmptr->cmsg_level = SOL_IP; | |
79 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 80 | #elif defined(IP_SENDSRCADDR) |
feba5c1d SK |
81 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
82 | *a = source->addr.addr4; | |
83 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
84 | cmptr->cmsg_level = IPPROTO_IP; | |
85 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 86 | #endif |
feba5c1d SK |
87 | } |
88 | } | |
44a2a316 SK |
89 | |
90 | #ifdef HAVE_IPV6 | |
feba5c1d | 91 | if (to->sa.sa_family == AF_INET6) |
44a2a316 | 92 | { |
feba5c1d SK |
93 | msg.msg_control = &control_u; |
94 | msg.msg_controllen = sizeof(control_u); | |
95 | { | |
96 | struct cmsghdr *cmptr = CMSG_FIRSTHDR(&msg); | |
97 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
dfa666f2 | 98 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ |
feba5c1d SK |
99 | pkt->ipi6_addr = source->addr.addr6; |
100 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
101 | cmptr->cmsg_type = IPV6_PKTINFO; | |
102 | cmptr->cmsg_level = IPV6_LEVEL; | |
103 | } | |
44a2a316 SK |
104 | } |
105 | #endif | |
feba5c1d SK |
106 | |
107 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack | |
108 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
109 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
110 | if (sendmsg(fd, &msg, 0) == -1 && errno == EINVAL) | |
111 | { | |
112 | msg.msg_controllen = 0; | |
113 | sendmsg(fd, &msg, 0); | |
114 | } | |
9e4abcb5 | 115 | } |
44a2a316 | 116 | |
36717eee SK |
117 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
118 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
119 | |
120 | { | |
121 | /* If the query ends in the domain in one of our servers, set | |
122 | domain to point to that name. We find the largest match to allow both | |
123 | domain.org and sub.domain.org to exist. */ | |
124 | ||
125 | unsigned int namelen = strlen(qdomain); | |
126 | unsigned int matchlen = 0; | |
127 | struct server *serv; | |
128 | unsigned short flags = 0; | |
129 | ||
3be34541 | 130 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d SK |
131 | /* domain matches take priority over NODOTS matches */ |
132 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.')) | |
133 | { | |
134 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
135 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 136 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
137 | flags = F_NXDOMAIN; |
138 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
139 | { | |
140 | if (sflag & qtype) | |
141 | { | |
142 | flags = sflag; | |
143 | if (serv->addr.sa.sa_family == AF_INET) | |
144 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 145 | #ifdef HAVE_IPV6 |
36717eee SK |
146 | else |
147 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 148 | #endif |
36717eee SK |
149 | } |
150 | else if (!flags) | |
151 | flags = F_NOERR; | |
152 | } | |
feba5c1d SK |
153 | } |
154 | else if (serv->flags & SERV_HAS_DOMAIN) | |
155 | { | |
156 | unsigned int domainlen = strlen(serv->domain); | |
157 | if (namelen >= domainlen && | |
158 | hostname_isequal(qdomain + namelen - domainlen, serv->domain) && | |
159 | domainlen >= matchlen) | |
160 | { | |
161 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
162 | *type = SERV_HAS_DOMAIN; | |
163 | *domain = serv->domain; | |
164 | matchlen = domainlen; | |
feba5c1d | 165 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
166 | flags = F_NXDOMAIN; |
167 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 168 | { |
36717eee SK |
169 | if ((sflag | F_QUERY ) & qtype) |
170 | { | |
171 | flags = qtype; | |
172 | if (serv->addr.sa.sa_family == AF_INET) | |
173 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 174 | #ifdef HAVE_IPV6 |
36717eee SK |
175 | else |
176 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 177 | #endif |
36717eee SK |
178 | } |
179 | else if (!flags) | |
180 | flags = F_NOERR; | |
feba5c1d SK |
181 | } |
182 | } | |
183 | } | |
184 | ||
36717eee | 185 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
186 | { |
187 | if (flags & F_QUERY) | |
c1bb8504 | 188 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0); |
feba5c1d | 189 | else |
c1bb8504 | 190 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0); |
feba5c1d | 191 | } |
3be34541 | 192 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.')) |
36717eee SK |
193 | flags = F_NXDOMAIN; |
194 | ||
195 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon->mxnames)) | |
c1bb8504 | 196 | flags = F_NOERR; |
feba5c1d | 197 | |
36717eee | 198 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
c1bb8504 | 199 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0); |
feba5c1d SK |
200 | |
201 | return flags; | |
202 | } | |
44a2a316 | 203 | |
9e4abcb5 | 204 | /* returns new last_server */ |
3be34541 SK |
205 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
206 | struct all_addr *dst_addr, unsigned int dst_iface, | |
207 | HEADER *header, int plen, time_t now) | |
9e4abcb5 SK |
208 | { |
209 | struct frec *forward; | |
210 | char *domain = NULL; | |
de37951c | 211 | int forwardall = 0, type = 0; |
9e4abcb5 SK |
212 | struct all_addr *addrp = NULL; |
213 | unsigned short flags = 0; | |
3be34541 | 214 | unsigned short gotname = extract_request(header, (unsigned int)plen, daemon->namebuff, NULL); |
de37951c SK |
215 | struct server *start = NULL; |
216 | ||
9e4abcb5 | 217 | /* may be recursion not speced or no servers available. */ |
3be34541 | 218 | if (!header->rd || !daemon->servers) |
9e4abcb5 SK |
219 | forward = NULL; |
220 | else if ((forward = lookup_frec_by_sender(ntohs(header->id), udpaddr))) | |
221 | { | |
de37951c | 222 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 223 | domain = forward->sentto->domain; |
3be34541 | 224 | if (!(daemon->options & OPT_ORDER)) |
de37951c SK |
225 | { |
226 | forwardall = 1; | |
3be34541 | 227 | daemon->last_server = NULL; |
de37951c | 228 | } |
9e4abcb5 | 229 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 230 | if (!(start = forward->sentto->next)) |
3be34541 | 231 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
232 | header->id = htons(forward->new_id); |
233 | } | |
234 | else | |
235 | { | |
236 | if (gotname) | |
36717eee | 237 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 238 | |
feba5c1d SK |
239 | if (!flags && !(forward = get_new_frec(now))) |
240 | /* table full - server failure. */ | |
241 | flags = F_NEG; | |
9e4abcb5 SK |
242 | |
243 | if (forward) | |
244 | { | |
245 | /* In strict_order mode, or when using domain specific servers | |
246 | always try servers in the order specified in resolv.conf, | |
247 | otherwise, use the one last known to work. */ | |
248 | ||
3be34541 SK |
249 | if (type != 0 || (daemon->options & OPT_ORDER)) |
250 | start = daemon->servers; | |
251 | else if (!(start = daemon->last_server)) | |
de37951c | 252 | { |
3be34541 | 253 | start = daemon->servers; |
de37951c SK |
254 | forwardall = 1; |
255 | } | |
feba5c1d | 256 | |
9e4abcb5 | 257 | forward->source = *udpaddr; |
44a2a316 | 258 | forward->dest = *dst_addr; |
dfa666f2 | 259 | forward->iface = dst_iface; |
9e4abcb5 SK |
260 | forward->new_id = get_id(); |
261 | forward->fd = udpfd; | |
262 | forward->orig_id = ntohs(header->id); | |
263 | header->id = htons(forward->new_id); | |
264 | } | |
265 | } | |
feba5c1d | 266 | |
9e4abcb5 SK |
267 | /* check for send errors here (no route to host) |
268 | if we fail to send to all nameservers, send back an error | |
269 | packet straight away (helps modem users when offline) */ | |
270 | ||
271 | if (!flags && forward) | |
272 | { | |
de37951c SK |
273 | struct server *firstsentto = start; |
274 | int forwarded = 0; | |
275 | ||
9e4abcb5 SK |
276 | while (1) |
277 | { | |
9e4abcb5 SK |
278 | /* only send to servers dealing with our domain. |
279 | domain may be NULL, in which case server->domain | |
280 | must be NULL also. */ | |
281 | ||
de37951c SK |
282 | if (type == (start->flags & SERV_TYPE) && |
283 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain))) | |
9e4abcb5 | 284 | { |
feba5c1d SK |
285 | if (!(start->flags & SERV_LITERAL_ADDRESS) && |
286 | sendto(start->sfd->fd, (char *)header, plen, 0, | |
287 | &start->addr.sa, | |
288 | sa_len(&start->addr)) != -1) | |
9e4abcb5 | 289 | { |
de37951c | 290 | if (!gotname) |
3be34541 | 291 | strcpy(daemon->namebuff, "query"); |
de37951c | 292 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 293 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 294 | (struct all_addr *)&start->addr.in.sin_addr, 0); |
de37951c SK |
295 | #ifdef HAVE_IPV6 |
296 | else | |
3be34541 | 297 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 298 | (struct all_addr *)&start->addr.in6.sin6_addr, 0); |
de37951c SK |
299 | #endif |
300 | forwarded = 1; | |
301 | forward->sentto = start; | |
302 | if (!forwardall) | |
303 | break; | |
9e4abcb5 SK |
304 | } |
305 | } | |
306 | ||
de37951c | 307 | if (!(start = start->next)) |
3be34541 | 308 | start = daemon->servers; |
9e4abcb5 | 309 | |
de37951c | 310 | if (start == firstsentto) |
9e4abcb5 SK |
311 | break; |
312 | } | |
313 | ||
de37951c | 314 | if (forwarded) |
3be34541 | 315 | return; |
de37951c | 316 | |
9e4abcb5 SK |
317 | /* could not send on, prepare to return */ |
318 | header->id = htons(forward->orig_id); | |
319 | forward->new_id = 0; /* cancel */ | |
320 | } | |
321 | ||
322 | /* could not send on, return empty answer or address if known for whole domain */ | |
3be34541 SK |
323 | plen = setup_reply(header, (unsigned int)plen, addrp, flags, daemon->local_ttl); |
324 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
44a2a316 | 325 | |
3be34541 | 326 | return; |
9e4abcb5 SK |
327 | } |
328 | ||
3be34541 | 329 | static int process_reply(struct daemon *daemon, HEADER *header, time_t now, |
36717eee | 330 | union mysockaddr *serveraddr, unsigned int n) |
feba5c1d | 331 | { |
36717eee SK |
332 | unsigned char *pheader, *sizep; |
333 | unsigned int plen; | |
feba5c1d SK |
334 | |
335 | /* If upstream is advertising a larger UDP packet size | |
336 | than we allow, trim it so that we don't get overlarge | |
337 | requests for the client. */ | |
338 | ||
36717eee | 339 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
340 | { |
341 | unsigned short udpsz; | |
36717eee | 342 | unsigned char *psave = sizep; |
feba5c1d | 343 | |
36717eee | 344 | GETSHORT(udpsz, sizep); |
3be34541 SK |
345 | if (udpsz > daemon->edns_pktsz) |
346 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
347 | } |
348 | ||
349 | /* Complain loudly if the upstream server is non-recursive. */ | |
350 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0) | |
351 | { | |
352 | char addrbuff[ADDRSTRLEN]; | |
353 | #ifdef HAVE_IPV6 | |
354 | if (serveraddr->sa.sa_family == AF_INET) | |
355 | inet_ntop(AF_INET, &serveraddr->in.sin_addr, addrbuff, ADDRSTRLEN); | |
356 | else if (serveraddr->sa.sa_family == AF_INET6) | |
357 | inet_ntop(AF_INET6, &serveraddr->in6.sin6_addr, addrbuff, ADDRSTRLEN); | |
358 | #else | |
359 | strcpy(addrbuff, inet_ntoa(serveraddr->in.sin_addr)); | |
360 | #endif | |
361 | syslog(LOG_WARNING, "nameserver %s refused to do a recursive query", addrbuff); | |
362 | return 0; | |
363 | } | |
364 | ||
36717eee SK |
365 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
366 | return n; | |
367 | ||
368 | if (header->rcode == NOERROR && ntohs(header->ancount) != 0) | |
feba5c1d | 369 | { |
3be34541 | 370 | if (!(daemon->bogus_addr && |
36717eee SK |
371 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now))) |
372 | extract_addresses(header, n, daemon->namebuff, now, daemon->doctors); | |
373 | } | |
374 | else | |
375 | { | |
376 | unsigned short flags = F_NEG; | |
377 | int munged = 0; | |
378 | ||
379 | if (header->rcode == NXDOMAIN) | |
380 | { | |
381 | /* if we forwarded a query for a locally known name (because it was for | |
382 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
383 | since we know that the domain exists, even if upstream doesn't */ | |
384 | if (extract_request(header, n, daemon->namebuff, NULL) && | |
385 | check_for_local_domain(daemon->namebuff, now, daemon->mxnames)) | |
386 | { | |
387 | munged = 1; | |
388 | header->rcode = NOERROR; | |
389 | } | |
390 | else | |
391 | flags |= F_NXDOMAIN; | |
392 | } | |
393 | ||
394 | if (!(daemon->options & OPT_NO_NEG)) | |
395 | extract_neg_addrs(header, n, daemon->namebuff, now, flags); | |
396 | ||
397 | /* do this after extract_neg_addrs. Ensure NODATA reply and remove | |
398 | nameserver info. */ | |
399 | if (munged) | |
feba5c1d | 400 | { |
36717eee SK |
401 | header->ancount = htons(0); |
402 | header->nscount = htons(0); | |
403 | header->arcount = htons(0); | |
feba5c1d SK |
404 | } |
405 | } | |
36717eee SK |
406 | |
407 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide | |
408 | sections of the packet. Find the new length here and put back pseudoheader | |
409 | if it was removed. */ | |
410 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
411 | } |
412 | ||
3be34541 SK |
413 | /* sets new last_server */ |
414 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
415 | { |
416 | /* packet from peer server, extract data for cache, and send to | |
417 | original requester */ | |
418 | struct frec *forward; | |
419 | HEADER *header; | |
de37951c SK |
420 | union mysockaddr serveraddr; |
421 | socklen_t addrlen = sizeof(serveraddr); | |
3be34541 | 422 | int n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
de37951c SK |
423 | |
424 | /* Determine the address of the server replying so that we can mark that as good */ | |
425 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
426 | #ifdef HAVE_IPV6 | |
427 | if (serveraddr.sa.sa_family == AF_INET6) | |
428 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
429 | #endif | |
9e4abcb5 | 430 | |
3be34541 | 431 | header = (HEADER *)daemon->packet; |
de37951c | 432 | if (n >= (int)sizeof(HEADER) && header->qr && (forward = lookup_frec(ntohs(header->id)))) |
9e4abcb5 | 433 | { |
de37951c SK |
434 | /* find good server by address if possible, otherwise assume the last one we sent to */ |
435 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
436 | { | |
3be34541 SK |
437 | struct server *last_server; |
438 | daemon->last_server = forward->sentto; | |
439 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
de37951c SK |
440 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && |
441 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
3be34541 SK |
442 | { |
443 | daemon->last_server = last_server; | |
444 | break; | |
445 | } | |
de37951c | 446 | } |
de37951c | 447 | |
36717eee | 448 | if ((n = process_reply(daemon, header, now, &serveraddr, (unsigned int)n))) |
3be34541 SK |
449 | { |
450 | header->id = htons(forward->orig_id); | |
451 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, n, | |
452 | &forward->source, &forward->dest, forward->iface); | |
453 | forward->new_id = 0; /* cancel */ | |
454 | } | |
9e4abcb5 | 455 | } |
9e4abcb5 | 456 | } |
44a2a316 | 457 | |
3be34541 | 458 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 459 | { |
3be34541 | 460 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 461 | union mysockaddr source_addr; |
c1bb8504 | 462 | unsigned short type; |
44a2a316 SK |
463 | struct iname *tmp; |
464 | struct all_addr dst_addr; | |
3be34541 | 465 | int check_dst = !(daemon->options & OPT_NOWILD); |
8a911ccc | 466 | int m, n, if_index = 0; |
44a2a316 SK |
467 | struct iovec iov[1]; |
468 | struct msghdr msg; | |
469 | struct cmsghdr *cmptr; | |
44a2a316 SK |
470 | union { |
471 | struct cmsghdr align; /* this ensures alignment */ | |
472 | #ifdef HAVE_IPV6 | |
473 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
474 | #endif | |
475 | #if defined(IP_PKTINFO) | |
476 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
477 | #elif defined(IP_RECVDSTADDR) | |
478 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
479 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
480 | #endif | |
481 | } control_u; | |
482 | ||
3be34541 SK |
483 | iov[0].iov_base = daemon->packet; |
484 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
485 | |
486 | msg.msg_control = control_u.control; | |
487 | msg.msg_controllen = sizeof(control_u); | |
488 | msg.msg_flags = 0; | |
489 | msg.msg_name = &source_addr; | |
490 | msg.msg_namelen = sizeof(source_addr); | |
491 | msg.msg_iov = iov; | |
492 | msg.msg_iovlen = 1; | |
493 | ||
de37951c | 494 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 495 | return; |
44a2a316 SK |
496 | |
497 | source_addr.sa.sa_family = listen->family; | |
498 | #ifdef HAVE_IPV6 | |
499 | if (listen->family == AF_INET6) | |
feba5c1d SK |
500 | { |
501 | check_dst = 1; | |
502 | source_addr.in6.sin6_flowinfo = htonl(0); | |
503 | } | |
44a2a316 SK |
504 | #endif |
505 | ||
feba5c1d | 506 | if (check_dst && msg.msg_controllen < sizeof(struct cmsghdr)) |
3be34541 | 507 | return; |
44a2a316 SK |
508 | |
509 | #if defined(IP_PKTINFO) | |
feba5c1d | 510 | if (check_dst && listen->family == AF_INET) |
44a2a316 SK |
511 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
512 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
513 | { | |
514 | dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; | |
8a911ccc | 515 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
44a2a316 SK |
516 | } |
517 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
feba5c1d | 518 | if (check_dst && listen->family == AF_INET) |
44a2a316 SK |
519 | { |
520 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
521 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
8a911ccc | 522 | dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
44a2a316 | 523 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
8a911ccc | 524 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; |
44a2a316 SK |
525 | } |
526 | #endif | |
527 | ||
528 | #ifdef HAVE_IPV6 | |
feba5c1d | 529 | if (listen->family == AF_INET6) |
44a2a316 SK |
530 | { |
531 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
532 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
533 | { | |
534 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
8a911ccc | 535 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; |
44a2a316 SK |
536 | } |
537 | } | |
538 | #endif | |
539 | ||
540 | if (n < (int)sizeof(HEADER) || header->qr) | |
3be34541 | 541 | return; |
44a2a316 SK |
542 | |
543 | /* enforce available interface configuration */ | |
feba5c1d | 544 | if (check_dst) |
44a2a316 | 545 | { |
8a911ccc SK |
546 | struct ifreq ifr; |
547 | ||
548 | if (if_index == 0) | |
3be34541 | 549 | return; |
44a2a316 | 550 | |
3be34541 | 551 | if (daemon->if_except || daemon->if_names) |
8a911ccc SK |
552 | { |
553 | #ifdef SIOCGIFNAME | |
554 | ifr.ifr_ifindex = if_index; | |
555 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 556 | return; |
8a911ccc SK |
557 | #else |
558 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 559 | return; |
8a911ccc SK |
560 | #endif |
561 | } | |
562 | ||
3be34541 | 563 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 564 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 565 | return; |
9e4abcb5 | 566 | |
3be34541 | 567 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 568 | { |
3be34541 | 569 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 570 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
571 | break; |
572 | if (!tmp) | |
3be34541 | 573 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
574 | if (tmp->addr.sa.sa_family == listen->family) |
575 | { | |
576 | if (tmp->addr.sa.sa_family == AF_INET && | |
577 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
578 | break; | |
579 | #ifdef HAVE_IPV6 | |
580 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
581 | memcmp(&tmp->addr.in6.sin6_addr, | |
582 | &dst_addr.addr.addr6, | |
583 | sizeof(struct in6_addr)) == 0) | |
584 | break; | |
585 | #endif | |
586 | } | |
587 | if (!tmp) | |
3be34541 | 588 | return; |
44a2a316 SK |
589 | } |
590 | } | |
591 | ||
3be34541 | 592 | if (extract_request(header, (unsigned int)n, daemon->namebuff, &type)) |
44a2a316 SK |
593 | { |
594 | if (listen->family == AF_INET) | |
3be34541 | 595 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 596 | (struct all_addr *)&source_addr.in.sin_addr, type); |
44a2a316 SK |
597 | #ifdef HAVE_IPV6 |
598 | else | |
3be34541 | 599 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 600 | (struct all_addr *)&source_addr.in6.sin6_addr, type); |
44a2a316 SK |
601 | #endif |
602 | } | |
603 | ||
3be34541 | 604 | m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n, daemon, now); |
44a2a316 | 605 | if (m >= 1) |
3be34541 | 606 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 607 | else |
3be34541 SK |
608 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
609 | header, n, now); | |
44a2a316 SK |
610 | } |
611 | ||
feba5c1d SK |
612 | static int read_write(int fd, char *packet, int size, int rw) |
613 | { | |
614 | int n, done; | |
615 | ||
616 | for (done = 0; done < size; done += n) | |
617 | { | |
618 | retry: | |
619 | if (rw) | |
620 | n = read(fd, &packet[done], (size_t)(size - done)); | |
621 | else | |
622 | n = write(fd, &packet[done], (size_t)(size - done)); | |
623 | ||
624 | if (n == 0) | |
625 | return 0; | |
626 | else if (n == -1) | |
627 | { | |
628 | if (errno == EINTR) | |
629 | goto retry; | |
630 | else if (errno == EAGAIN) | |
631 | { | |
632 | struct timespec waiter; | |
633 | waiter.tv_sec = 0; | |
634 | waiter.tv_nsec = 10000; | |
635 | nanosleep(&waiter, NULL); | |
636 | goto retry; | |
637 | } | |
638 | else | |
639 | return 0; | |
640 | } | |
641 | } | |
642 | return 1; | |
643 | } | |
644 | ||
645 | /* The daemon forks before calling this: it should deal with one connection, | |
646 | blocking as neccessary, and then return. Note, need to be a bit careful | |
647 | about resources for debug mode, when the fork is suppressed: that's | |
648 | done by the caller. */ | |
3be34541 | 649 | char *tcp_request(struct daemon *daemon, int confd, time_t now) |
feba5c1d SK |
650 | { |
651 | int size = 0, m; | |
c1bb8504 | 652 | unsigned short qtype, gotname; |
feba5c1d SK |
653 | unsigned char c1, c2; |
654 | /* Max TCP packet + slop */ | |
655 | char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); | |
656 | HEADER *header; | |
3be34541 SK |
657 | struct server *last_server; |
658 | ||
feba5c1d SK |
659 | while (1) |
660 | { | |
661 | if (!packet || | |
662 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
663 | !(size = c1 << 8 | c2) || | |
664 | !read_write(confd, packet, size, 1)) | |
665 | return packet; | |
666 | ||
667 | if (size < (int)sizeof(HEADER)) | |
668 | continue; | |
669 | ||
670 | header = (HEADER *)packet; | |
671 | ||
3be34541 | 672 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
673 | { |
674 | union mysockaddr peer_addr; | |
675 | socklen_t peer_len = sizeof(union mysockaddr); | |
676 | ||
677 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
678 | { | |
679 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 680 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 681 | (struct all_addr *)&peer_addr.in.sin_addr, qtype); |
feba5c1d SK |
682 | #ifdef HAVE_IPV6 |
683 | else | |
3be34541 | 684 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 685 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype); |
feba5c1d SK |
686 | #endif |
687 | } | |
688 | } | |
689 | ||
690 | /* m > 0 if answered from cache */ | |
3be34541 | 691 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, now); |
feba5c1d SK |
692 | |
693 | if (m == 0) | |
694 | { | |
695 | unsigned short flags = 0; | |
feba5c1d SK |
696 | struct all_addr *addrp = NULL; |
697 | int type = 0; | |
698 | char *domain = NULL; | |
699 | ||
700 | if (gotname) | |
36717eee | 701 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 702 | |
3be34541 SK |
703 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
704 | last_server = daemon->servers; | |
705 | else | |
706 | last_server = daemon->last_server; | |
feba5c1d SK |
707 | |
708 | if (!flags && last_server) | |
709 | { | |
710 | struct server *firstsendto = NULL; | |
711 | ||
712 | /* Loop round available servers until we succeed in connecting to one. | |
713 | Note that this code subtley ensures that consecutive queries on this connection | |
714 | which can go to the same server, do so. */ | |
715 | while (1) | |
716 | { | |
717 | if (!firstsendto) | |
718 | firstsendto = last_server; | |
719 | else | |
720 | { | |
721 | if (!(last_server = last_server->next)) | |
3be34541 | 722 | last_server = daemon->servers; |
feba5c1d SK |
723 | |
724 | if (last_server == firstsendto) | |
725 | break; | |
726 | } | |
727 | ||
728 | /* server for wrong domain */ | |
729 | if (type != (last_server->flags & SERV_TYPE) || | |
730 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
731 | continue; | |
732 | ||
733 | if ((last_server->tcpfd == -1) && | |
734 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
735 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
736 | { | |
737 | close(last_server->tcpfd); | |
738 | last_server->tcpfd = -1; | |
739 | } | |
740 | ||
741 | if (last_server->tcpfd == -1) | |
742 | continue; | |
743 | ||
744 | c1 = size >> 8; | |
745 | c2 = size; | |
746 | ||
747 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
748 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
749 | !read_write(last_server->tcpfd, packet, size, 0) || | |
750 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
751 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
752 | { | |
753 | close(last_server->tcpfd); | |
754 | last_server->tcpfd = -1; | |
755 | continue; | |
756 | } | |
757 | ||
758 | m = (c1 << 8) | c2; | |
759 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
760 | return packet; | |
761 | ||
762 | if (!gotname) | |
3be34541 | 763 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 764 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 765 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 766 | (struct all_addr *)&last_server->addr.in.sin_addr, 0); |
feba5c1d SK |
767 | #ifdef HAVE_IPV6 |
768 | else | |
3be34541 | 769 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 770 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0); |
feba5c1d SK |
771 | #endif |
772 | ||
773 | /* There's no point in updating the cache, since this process will exit and | |
774 | lose the information after one query. We make this call for the alias and | |
775 | bogus-nxdomain side-effects. */ | |
36717eee | 776 | m = process_reply(daemon, header, now, &last_server->addr, (unsigned int)m); |
feba5c1d SK |
777 | |
778 | break; | |
779 | } | |
780 | } | |
781 | ||
782 | /* In case of local answer or no connections made. */ | |
783 | if (m == 0) | |
3be34541 | 784 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
785 | } |
786 | ||
787 | c1 = m>>8; | |
788 | c2 = m; | |
789 | if (!read_write(confd, &c1, 1, 0) || | |
790 | !read_write(confd, &c2, 1, 0) || | |
791 | !read_write(confd, packet, m, 0)) | |
792 | return packet; | |
793 | } | |
794 | } | |
795 | ||
9e4abcb5 SK |
796 | static struct frec *get_new_frec(time_t now) |
797 | { | |
798 | struct frec *f = frec_list, *oldest = NULL; | |
799 | time_t oldtime = now; | |
800 | int count = 0; | |
801 | static time_t warntime = 0; | |
802 | ||
803 | while (f) | |
804 | { | |
805 | if (f->new_id == 0) | |
806 | { | |
807 | f->time = now; | |
808 | return f; | |
809 | } | |
810 | ||
811 | if (difftime(f->time, oldtime) <= 0) | |
812 | { | |
813 | oldtime = f->time; | |
814 | oldest = f; | |
815 | } | |
816 | ||
817 | count++; | |
818 | f = f->next; | |
819 | } | |
820 | ||
821 | /* can't find empty one, use oldest if there is one | |
822 | and it's older than timeout */ | |
823 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
824 | { | |
825 | oldest->time = now; | |
826 | return oldest; | |
827 | } | |
828 | ||
829 | if (count > FTABSIZ) | |
830 | { /* limit logging rate so syslog isn't DOSed either */ | |
831 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
832 | { | |
833 | warntime = now; | |
834 | syslog(LOG_WARNING, "forwarding table overflow: check for server loops."); | |
835 | } | |
836 | return NULL; | |
837 | } | |
838 | ||
839 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
840 | { | |
841 | f->next = frec_list; | |
842 | f->time = now; | |
843 | frec_list = f; | |
844 | } | |
845 | return f; /* OK if malloc fails and this is NULL */ | |
846 | } | |
847 | ||
848 | static struct frec *lookup_frec(unsigned short id) | |
849 | { | |
850 | struct frec *f; | |
851 | ||
852 | for(f = frec_list; f; f = f->next) | |
853 | if (f->new_id == id) | |
854 | return f; | |
855 | ||
856 | return NULL; | |
857 | } | |
858 | ||
859 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
860 | union mysockaddr *addr) | |
861 | { | |
feba5c1d SK |
862 | struct frec *f; |
863 | ||
9e4abcb5 SK |
864 | for(f = frec_list; f; f = f->next) |
865 | if (f->new_id && | |
866 | f->orig_id == id && | |
867 | sockaddr_isequal(&f->source, addr)) | |
868 | return f; | |
869 | ||
870 | return NULL; | |
871 | } | |
872 | ||
873 | ||
874 | /* return unique random ids between 1 and 65535 */ | |
875 | static unsigned short get_id(void) | |
876 | { | |
877 | unsigned short ret = 0; | |
878 | ||
879 | while (ret == 0) | |
880 | { | |
881 | ret = rand16(); | |
882 | ||
883 | /* scrap ids already in use */ | |
884 | if ((ret != 0) && lookup_frec(ret)) | |
885 | ret = 0; | |
886 | } | |
887 | ||
888 | return ret; | |
889 | } | |
890 | ||
891 | ||
892 | ||
893 | ||
894 |