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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 SK |
91 | } |
92 | ||
44a2a316 | 93 | #ifdef HAVE_IPV6 |
26128d27 SK |
94 | else |
95 | { | |
96 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
97 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
98 | pkt->ipi6_addr = source->addr.addr6; | |
99 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
100 | cmptr->cmsg_type = IPV6_PKTINFO; | |
101 | cmptr->cmsg_level = IPV6_LEVEL; | |
102 | } | |
44a2a316 | 103 | #endif |
26128d27 | 104 | } |
feba5c1d | 105 | |
fd9fa481 SK |
106 | retry: |
107 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 108 | { |
fd9fa481 SK |
109 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
110 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
111 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
112 | if (errno == EINVAL && msg.msg_controllen) | |
113 | { | |
114 | msg.msg_controllen = 0; | |
115 | goto retry; | |
116 | } | |
117 | if (retry_send()) | |
118 | goto retry; | |
feba5c1d | 119 | } |
9e4abcb5 | 120 | } |
44a2a316 | 121 | |
36717eee SK |
122 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
123 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
124 | |
125 | { | |
126 | /* If the query ends in the domain in one of our servers, set | |
127 | domain to point to that name. We find the largest match to allow both | |
128 | domain.org and sub.domain.org to exist. */ | |
129 | ||
130 | unsigned int namelen = strlen(qdomain); | |
131 | unsigned int matchlen = 0; | |
132 | struct server *serv; | |
133 | unsigned short flags = 0; | |
134 | ||
3be34541 | 135 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d SK |
136 | /* domain matches take priority over NODOTS matches */ |
137 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.')) | |
138 | { | |
139 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
140 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 141 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
142 | flags = F_NXDOMAIN; |
143 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
144 | { | |
145 | if (sflag & qtype) | |
146 | { | |
147 | flags = sflag; | |
148 | if (serv->addr.sa.sa_family == AF_INET) | |
149 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 150 | #ifdef HAVE_IPV6 |
36717eee SK |
151 | else |
152 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 153 | #endif |
36717eee SK |
154 | } |
155 | else if (!flags) | |
156 | flags = F_NOERR; | |
157 | } | |
feba5c1d SK |
158 | } |
159 | else if (serv->flags & SERV_HAS_DOMAIN) | |
160 | { | |
161 | unsigned int domainlen = strlen(serv->domain); | |
162 | if (namelen >= domainlen && | |
163 | hostname_isequal(qdomain + namelen - domainlen, serv->domain) && | |
164 | domainlen >= matchlen) | |
165 | { | |
166 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
167 | *type = SERV_HAS_DOMAIN; | |
168 | *domain = serv->domain; | |
169 | matchlen = domainlen; | |
feba5c1d | 170 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
171 | flags = F_NXDOMAIN; |
172 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 173 | { |
36717eee SK |
174 | if ((sflag | F_QUERY ) & qtype) |
175 | { | |
176 | flags = qtype; | |
177 | if (serv->addr.sa.sa_family == AF_INET) | |
178 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 179 | #ifdef HAVE_IPV6 |
36717eee SK |
180 | else |
181 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 182 | #endif |
36717eee SK |
183 | } |
184 | else if (!flags) | |
185 | flags = F_NOERR; | |
feba5c1d SK |
186 | } |
187 | } | |
188 | } | |
189 | ||
36717eee | 190 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
191 | { |
192 | if (flags & F_QUERY) | |
fd9fa481 | 193 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0, NULL, 0); |
feba5c1d | 194 | else |
fd9fa481 | 195 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0, NULL, 0); |
feba5c1d | 196 | } |
3be34541 | 197 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.')) |
36717eee SK |
198 | flags = F_NXDOMAIN; |
199 | ||
f6b7dc47 | 200 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon)) |
c1bb8504 | 201 | flags = F_NOERR; |
feba5c1d | 202 | |
36717eee | 203 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
fd9fa481 | 204 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0, NULL, 0); |
feba5c1d SK |
205 | |
206 | return flags; | |
207 | } | |
44a2a316 | 208 | |
9e4abcb5 | 209 | /* returns new last_server */ |
3be34541 SK |
210 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
211 | struct all_addr *dst_addr, unsigned int dst_iface, | |
212 | HEADER *header, int plen, time_t now) | |
9e4abcb5 SK |
213 | { |
214 | struct frec *forward; | |
215 | char *domain = NULL; | |
de37951c | 216 | int forwardall = 0, type = 0; |
9e4abcb5 SK |
217 | struct all_addr *addrp = NULL; |
218 | unsigned short flags = 0; | |
3be34541 | 219 | unsigned short gotname = extract_request(header, (unsigned int)plen, daemon->namebuff, NULL); |
de37951c | 220 | struct server *start = NULL; |
fd9fa481 | 221 | unsigned int crc = questions_crc(header,(unsigned int)plen); |
de37951c | 222 | |
9e4abcb5 | 223 | /* may be recursion not speced or no servers available. */ |
3be34541 | 224 | if (!header->rd || !daemon->servers) |
9e4abcb5 | 225 | forward = NULL; |
fd9fa481 | 226 | else if ((forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 227 | { |
de37951c | 228 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 229 | domain = forward->sentto->domain; |
3be34541 | 230 | if (!(daemon->options & OPT_ORDER)) |
de37951c SK |
231 | { |
232 | forwardall = 1; | |
3be34541 | 233 | daemon->last_server = NULL; |
de37951c | 234 | } |
9e4abcb5 | 235 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 236 | if (!(start = forward->sentto->next)) |
3be34541 | 237 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
238 | header->id = htons(forward->new_id); |
239 | } | |
240 | else | |
241 | { | |
242 | if (gotname) | |
36717eee | 243 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 244 | |
feba5c1d SK |
245 | if (!flags && !(forward = get_new_frec(now))) |
246 | /* table full - server failure. */ | |
247 | flags = F_NEG; | |
9e4abcb5 SK |
248 | |
249 | if (forward) | |
250 | { | |
251 | /* In strict_order mode, or when using domain specific servers | |
252 | always try servers in the order specified in resolv.conf, | |
253 | otherwise, use the one last known to work. */ | |
254 | ||
3be34541 SK |
255 | if (type != 0 || (daemon->options & OPT_ORDER)) |
256 | start = daemon->servers; | |
257 | else if (!(start = daemon->last_server)) | |
de37951c | 258 | { |
3be34541 | 259 | start = daemon->servers; |
de37951c SK |
260 | forwardall = 1; |
261 | } | |
feba5c1d | 262 | |
9e4abcb5 | 263 | forward->source = *udpaddr; |
44a2a316 | 264 | forward->dest = *dst_addr; |
dfa666f2 | 265 | forward->iface = dst_iface; |
9e4abcb5 SK |
266 | forward->new_id = get_id(); |
267 | forward->fd = udpfd; | |
268 | forward->orig_id = ntohs(header->id); | |
fd9fa481 | 269 | forward->crc = crc; |
9e4abcb5 SK |
270 | header->id = htons(forward->new_id); |
271 | } | |
272 | } | |
feba5c1d | 273 | |
9e4abcb5 SK |
274 | /* check for send errors here (no route to host) |
275 | if we fail to send to all nameservers, send back an error | |
276 | packet straight away (helps modem users when offline) */ | |
277 | ||
278 | if (!flags && forward) | |
279 | { | |
de37951c SK |
280 | struct server *firstsentto = start; |
281 | int forwarded = 0; | |
282 | ||
9e4abcb5 SK |
283 | while (1) |
284 | { | |
9e4abcb5 SK |
285 | /* only send to servers dealing with our domain. |
286 | domain may be NULL, in which case server->domain | |
287 | must be NULL also. */ | |
288 | ||
de37951c | 289 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
290 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
291 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 292 | { |
fd9fa481 | 293 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 294 | &start->addr.sa, |
fd9fa481 SK |
295 | sa_len(&start->addr)) == -1) |
296 | { | |
297 | if (retry_send()) | |
298 | continue; | |
299 | } | |
300 | else | |
9e4abcb5 | 301 | { |
de37951c | 302 | if (!gotname) |
3be34541 | 303 | strcpy(daemon->namebuff, "query"); |
de37951c | 304 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 305 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
306 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
307 | NULL, 0); | |
de37951c SK |
308 | #ifdef HAVE_IPV6 |
309 | else | |
3be34541 | 310 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
311 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
312 | NULL, 0); | |
de37951c SK |
313 | #endif |
314 | forwarded = 1; | |
315 | forward->sentto = start; | |
316 | if (!forwardall) | |
317 | break; | |
9e4abcb5 SK |
318 | } |
319 | } | |
320 | ||
de37951c | 321 | if (!(start = start->next)) |
3be34541 | 322 | start = daemon->servers; |
9e4abcb5 | 323 | |
de37951c | 324 | if (start == firstsentto) |
9e4abcb5 SK |
325 | break; |
326 | } | |
327 | ||
de37951c | 328 | if (forwarded) |
3be34541 | 329 | return; |
de37951c | 330 | |
9e4abcb5 SK |
331 | /* could not send on, prepare to return */ |
332 | header->id = htons(forward->orig_id); | |
333 | forward->new_id = 0; /* cancel */ | |
334 | } | |
335 | ||
336 | /* could not send on, return empty answer or address if known for whole domain */ | |
3be34541 SK |
337 | plen = setup_reply(header, (unsigned int)plen, addrp, flags, daemon->local_ttl); |
338 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
44a2a316 | 339 | |
3be34541 | 340 | return; |
9e4abcb5 SK |
341 | } |
342 | ||
3be34541 | 343 | static int process_reply(struct daemon *daemon, HEADER *header, time_t now, |
36717eee | 344 | union mysockaddr *serveraddr, unsigned int n) |
feba5c1d | 345 | { |
36717eee | 346 | unsigned char *pheader, *sizep; |
fd9fa481 | 347 | unsigned int plen, munged = 0; |
feba5c1d SK |
348 | |
349 | /* If upstream is advertising a larger UDP packet size | |
350 | than we allow, trim it so that we don't get overlarge | |
351 | requests for the client. */ | |
352 | ||
36717eee | 353 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
354 | { |
355 | unsigned short udpsz; | |
36717eee | 356 | unsigned char *psave = sizep; |
feba5c1d | 357 | |
36717eee | 358 | GETSHORT(udpsz, sizep); |
3be34541 SK |
359 | if (udpsz > daemon->edns_pktsz) |
360 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
361 | } |
362 | ||
363 | /* Complain loudly if the upstream server is non-recursive. */ | |
364 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0) | |
365 | { | |
366 | char addrbuff[ADDRSTRLEN]; | |
367 | #ifdef HAVE_IPV6 | |
368 | if (serveraddr->sa.sa_family == AF_INET) | |
369 | inet_ntop(AF_INET, &serveraddr->in.sin_addr, addrbuff, ADDRSTRLEN); | |
370 | else if (serveraddr->sa.sa_family == AF_INET6) | |
371 | inet_ntop(AF_INET6, &serveraddr->in6.sin6_addr, addrbuff, ADDRSTRLEN); | |
372 | #else | |
373 | strcpy(addrbuff, inet_ntoa(serveraddr->in.sin_addr)); | |
374 | #endif | |
375 | syslog(LOG_WARNING, "nameserver %s refused to do a recursive query", addrbuff); | |
376 | return 0; | |
377 | } | |
378 | ||
36717eee SK |
379 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
380 | return n; | |
381 | ||
fd9fa481 SK |
382 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
383 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 384 | { |
fd9fa481 SK |
385 | munged = 1; |
386 | header->rcode = NXDOMAIN; | |
387 | header->aa = 0; | |
36717eee | 388 | } |
fd9fa481 | 389 | else |
36717eee | 390 | { |
fd9fa481 SK |
391 | if (header->rcode == NXDOMAIN && |
392 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 393 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
394 | { |
395 | /* if we forwarded a query for a locally known name (because it was for | |
396 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
397 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
398 | munged = 1; |
399 | header->aa = 1; | |
400 | header->rcode = NOERROR; | |
feba5c1d | 401 | } |
fd9fa481 SK |
402 | |
403 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 404 | } |
fd9fa481 SK |
405 | |
406 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
407 | nameserver info. */ | |
408 | ||
409 | if (munged) | |
410 | { | |
411 | header->ancount = htons(0); | |
412 | header->nscount = htons(0); | |
413 | header->arcount = htons(0); | |
414 | } | |
415 | ||
36717eee SK |
416 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
417 | sections of the packet. Find the new length here and put back pseudoheader | |
418 | if it was removed. */ | |
419 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
420 | } |
421 | ||
3be34541 SK |
422 | /* sets new last_server */ |
423 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
424 | { |
425 | /* packet from peer server, extract data for cache, and send to | |
426 | original requester */ | |
427 | struct frec *forward; | |
428 | HEADER *header; | |
de37951c SK |
429 | union mysockaddr serveraddr; |
430 | socklen_t addrlen = sizeof(serveraddr); | |
3be34541 | 431 | int n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
de37951c SK |
432 | |
433 | /* Determine the address of the server replying so that we can mark that as good */ | |
434 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
435 | #ifdef HAVE_IPV6 | |
436 | if (serveraddr.sa.sa_family == AF_INET6) | |
437 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
438 | #endif | |
9e4abcb5 | 439 | |
3be34541 | 440 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
441 | forward = lookup_frec(ntohs(header->id)); |
442 | ||
443 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 444 | { |
de37951c SK |
445 | /* find good server by address if possible, otherwise assume the last one we sent to */ |
446 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
447 | { | |
3be34541 SK |
448 | struct server *last_server; |
449 | daemon->last_server = forward->sentto; | |
450 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
de37951c SK |
451 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && |
452 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
3be34541 SK |
453 | { |
454 | daemon->last_server = last_server; | |
455 | break; | |
456 | } | |
de37951c | 457 | } |
de37951c | 458 | |
36717eee | 459 | if ((n = process_reply(daemon, header, now, &serveraddr, (unsigned int)n))) |
3be34541 SK |
460 | { |
461 | header->id = htons(forward->orig_id); | |
fd9fa481 | 462 | header->ra = 1; /* recursion if available */ |
26128d27 | 463 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, n, |
3be34541 SK |
464 | &forward->source, &forward->dest, forward->iface); |
465 | forward->new_id = 0; /* cancel */ | |
466 | } | |
9e4abcb5 | 467 | } |
9e4abcb5 | 468 | } |
44a2a316 | 469 | |
3be34541 | 470 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 471 | { |
3be34541 | 472 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 473 | union mysockaddr source_addr; |
c1bb8504 | 474 | unsigned short type; |
44a2a316 SK |
475 | struct iname *tmp; |
476 | struct all_addr dst_addr; | |
f6b7dc47 | 477 | struct in_addr netmask, dst_addr_4; |
8a911ccc | 478 | int m, n, if_index = 0; |
44a2a316 SK |
479 | struct iovec iov[1]; |
480 | struct msghdr msg; | |
481 | struct cmsghdr *cmptr; | |
44a2a316 SK |
482 | union { |
483 | struct cmsghdr align; /* this ensures alignment */ | |
484 | #ifdef HAVE_IPV6 | |
485 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
486 | #endif | |
487 | #if defined(IP_PKTINFO) | |
488 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
489 | #elif defined(IP_RECVDSTADDR) | |
490 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
491 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
492 | #endif | |
493 | } control_u; | |
494 | ||
f6b7dc47 SK |
495 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
496 | { | |
497 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
498 | netmask = listen->iface->netmask; | |
499 | } | |
500 | else | |
501 | dst_addr_4.s_addr = 0; | |
502 | ||
3be34541 SK |
503 | iov[0].iov_base = daemon->packet; |
504 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
505 | |
506 | msg.msg_control = control_u.control; | |
507 | msg.msg_controllen = sizeof(control_u); | |
508 | msg.msg_flags = 0; | |
509 | msg.msg_name = &source_addr; | |
510 | msg.msg_namelen = sizeof(source_addr); | |
511 | msg.msg_iov = iov; | |
512 | msg.msg_iovlen = 1; | |
513 | ||
de37951c | 514 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 515 | return; |
44a2a316 | 516 | |
26128d27 SK |
517 | if (n < (int)sizeof(HEADER) || header->qr) |
518 | return; | |
519 | ||
44a2a316 SK |
520 | source_addr.sa.sa_family = listen->family; |
521 | #ifdef HAVE_IPV6 | |
522 | if (listen->family == AF_INET6) | |
26128d27 | 523 | source_addr.in6.sin6_flowinfo = htonl(0); |
44a2a316 SK |
524 | #endif |
525 | ||
26128d27 SK |
526 | if (!(daemon->options & OPT_NOWILD)) |
527 | { | |
528 | struct ifreq ifr; | |
529 | ||
530 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
531 | return; | |
44a2a316 SK |
532 | |
533 | #if defined(IP_PKTINFO) | |
26128d27 SK |
534 | if (listen->family == AF_INET) |
535 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
536 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
537 | { | |
f6b7dc47 | 538 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
539 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
540 | } | |
541 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
542 | if (listen->family == AF_INET) | |
44a2a316 | 543 | { |
26128d27 SK |
544 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
545 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 546 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
547 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
548 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 549 | } |
44a2a316 | 550 | #endif |
26128d27 | 551 | |
44a2a316 | 552 | #ifdef HAVE_IPV6 |
26128d27 SK |
553 | if (listen->family == AF_INET6) |
554 | { | |
555 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
556 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
557 | { | |
558 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
559 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
560 | } | |
561 | } | |
44a2a316 | 562 | #endif |
26128d27 SK |
563 | |
564 | /* enforce available interface configuration */ | |
565 | ||
8a911ccc | 566 | if (if_index == 0) |
3be34541 | 567 | return; |
44a2a316 | 568 | |
f6b7dc47 | 569 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
570 | { |
571 | #ifdef SIOCGIFNAME | |
572 | ifr.ifr_ifindex = if_index; | |
573 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 574 | return; |
8a911ccc SK |
575 | #else |
576 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 577 | return; |
8a911ccc | 578 | #endif |
f6b7dc47 SK |
579 | |
580 | if (listen->family == AF_INET && | |
581 | (daemon->options & OPT_LOCALISE) && | |
582 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
583 | return; | |
584 | ||
585 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
586 | } |
587 | ||
3be34541 | 588 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 589 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 590 | return; |
9e4abcb5 | 591 | |
3be34541 | 592 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 593 | { |
3be34541 | 594 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 595 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
596 | break; |
597 | if (!tmp) | |
3be34541 | 598 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
599 | if (tmp->addr.sa.sa_family == listen->family) |
600 | { | |
601 | if (tmp->addr.sa.sa_family == AF_INET && | |
602 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
603 | break; | |
604 | #ifdef HAVE_IPV6 | |
605 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
606 | memcmp(&tmp->addr.in6.sin6_addr, | |
607 | &dst_addr.addr.addr6, | |
608 | sizeof(struct in6_addr)) == 0) | |
609 | break; | |
610 | #endif | |
611 | } | |
612 | if (!tmp) | |
3be34541 | 613 | return; |
44a2a316 SK |
614 | } |
615 | } | |
616 | ||
3be34541 | 617 | if (extract_request(header, (unsigned int)n, daemon->namebuff, &type)) |
44a2a316 SK |
618 | { |
619 | if (listen->family == AF_INET) | |
3be34541 | 620 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 621 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
622 | #ifdef HAVE_IPV6 |
623 | else | |
3be34541 | 624 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 625 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
626 | #endif |
627 | } | |
628 | ||
f6b7dc47 SK |
629 | m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n, daemon, |
630 | dst_addr_4, netmask, now); | |
44a2a316 | 631 | if (m >= 1) |
3be34541 | 632 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 633 | else |
3be34541 SK |
634 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
635 | header, n, now); | |
44a2a316 SK |
636 | } |
637 | ||
feba5c1d SK |
638 | static int read_write(int fd, char *packet, int size, int rw) |
639 | { | |
640 | int n, done; | |
641 | ||
642 | for (done = 0; done < size; done += n) | |
643 | { | |
644 | retry: | |
645 | if (rw) | |
646 | n = read(fd, &packet[done], (size_t)(size - done)); | |
647 | else | |
648 | n = write(fd, &packet[done], (size_t)(size - done)); | |
649 | ||
650 | if (n == 0) | |
651 | return 0; | |
652 | else if (n == -1) | |
653 | { | |
fd9fa481 | 654 | if (retry_send()) |
feba5c1d | 655 | goto retry; |
feba5c1d SK |
656 | else |
657 | return 0; | |
658 | } | |
659 | } | |
660 | return 1; | |
661 | } | |
662 | ||
663 | /* The daemon forks before calling this: it should deal with one connection, | |
664 | blocking as neccessary, and then return. Note, need to be a bit careful | |
665 | about resources for debug mode, when the fork is suppressed: that's | |
666 | done by the caller. */ | |
f6b7dc47 SK |
667 | char *tcp_request(struct daemon *daemon, int confd, time_t now, |
668 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d SK |
669 | { |
670 | int size = 0, m; | |
c1bb8504 | 671 | unsigned short qtype, gotname; |
feba5c1d SK |
672 | unsigned char c1, c2; |
673 | /* Max TCP packet + slop */ | |
674 | char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); | |
675 | HEADER *header; | |
3be34541 SK |
676 | struct server *last_server; |
677 | ||
feba5c1d SK |
678 | while (1) |
679 | { | |
680 | if (!packet || | |
681 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
682 | !(size = c1 << 8 | c2) || | |
683 | !read_write(confd, packet, size, 1)) | |
684 | return packet; | |
685 | ||
686 | if (size < (int)sizeof(HEADER)) | |
687 | continue; | |
688 | ||
689 | header = (HEADER *)packet; | |
690 | ||
3be34541 | 691 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
692 | { |
693 | union mysockaddr peer_addr; | |
694 | socklen_t peer_len = sizeof(union mysockaddr); | |
695 | ||
696 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
697 | { | |
698 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 699 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 700 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
701 | #ifdef HAVE_IPV6 |
702 | else | |
3be34541 | 703 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 704 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
705 | #endif |
706 | } | |
707 | } | |
708 | ||
709 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
710 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
711 | local_addr, netmask, now); | |
feba5c1d SK |
712 | |
713 | if (m == 0) | |
714 | { | |
715 | unsigned short flags = 0; | |
feba5c1d SK |
716 | struct all_addr *addrp = NULL; |
717 | int type = 0; | |
718 | char *domain = NULL; | |
719 | ||
720 | if (gotname) | |
36717eee | 721 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 722 | |
3be34541 SK |
723 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
724 | last_server = daemon->servers; | |
725 | else | |
726 | last_server = daemon->last_server; | |
feba5c1d SK |
727 | |
728 | if (!flags && last_server) | |
729 | { | |
730 | struct server *firstsendto = NULL; | |
731 | ||
732 | /* Loop round available servers until we succeed in connecting to one. | |
733 | Note that this code subtley ensures that consecutive queries on this connection | |
734 | which can go to the same server, do so. */ | |
735 | while (1) | |
736 | { | |
737 | if (!firstsendto) | |
738 | firstsendto = last_server; | |
739 | else | |
740 | { | |
741 | if (!(last_server = last_server->next)) | |
3be34541 | 742 | last_server = daemon->servers; |
feba5c1d SK |
743 | |
744 | if (last_server == firstsendto) | |
745 | break; | |
746 | } | |
747 | ||
748 | /* server for wrong domain */ | |
749 | if (type != (last_server->flags & SERV_TYPE) || | |
750 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
751 | continue; | |
752 | ||
753 | if ((last_server->tcpfd == -1) && | |
754 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
755 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
756 | { | |
757 | close(last_server->tcpfd); | |
758 | last_server->tcpfd = -1; | |
759 | } | |
760 | ||
761 | if (last_server->tcpfd == -1) | |
762 | continue; | |
763 | ||
764 | c1 = size >> 8; | |
765 | c2 = size; | |
766 | ||
767 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
768 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
769 | !read_write(last_server->tcpfd, packet, size, 0) || | |
770 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
771 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
772 | { | |
773 | close(last_server->tcpfd); | |
774 | last_server->tcpfd = -1; | |
775 | continue; | |
776 | } | |
777 | ||
778 | m = (c1 << 8) | c2; | |
779 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
780 | return packet; | |
781 | ||
782 | if (!gotname) | |
3be34541 | 783 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 784 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 785 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 786 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
787 | #ifdef HAVE_IPV6 |
788 | else | |
3be34541 | 789 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 790 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
791 | #endif |
792 | ||
793 | /* There's no point in updating the cache, since this process will exit and | |
794 | lose the information after one query. We make this call for the alias and | |
795 | bogus-nxdomain side-effects. */ | |
36717eee | 796 | m = process_reply(daemon, header, now, &last_server->addr, (unsigned int)m); |
feba5c1d SK |
797 | |
798 | break; | |
799 | } | |
800 | } | |
801 | ||
802 | /* In case of local answer or no connections made. */ | |
803 | if (m == 0) | |
3be34541 | 804 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
805 | } |
806 | ||
807 | c1 = m>>8; | |
808 | c2 = m; | |
809 | if (!read_write(confd, &c1, 1, 0) || | |
810 | !read_write(confd, &c2, 1, 0) || | |
811 | !read_write(confd, packet, m, 0)) | |
812 | return packet; | |
813 | } | |
814 | } | |
815 | ||
9e4abcb5 SK |
816 | static struct frec *get_new_frec(time_t now) |
817 | { | |
818 | struct frec *f = frec_list, *oldest = NULL; | |
819 | time_t oldtime = now; | |
820 | int count = 0; | |
821 | static time_t warntime = 0; | |
822 | ||
823 | while (f) | |
824 | { | |
825 | if (f->new_id == 0) | |
826 | { | |
827 | f->time = now; | |
828 | return f; | |
829 | } | |
830 | ||
831 | if (difftime(f->time, oldtime) <= 0) | |
832 | { | |
833 | oldtime = f->time; | |
834 | oldest = f; | |
835 | } | |
836 | ||
837 | count++; | |
838 | f = f->next; | |
839 | } | |
840 | ||
841 | /* can't find empty one, use oldest if there is one | |
842 | and it's older than timeout */ | |
843 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
844 | { | |
845 | oldest->time = now; | |
846 | return oldest; | |
847 | } | |
848 | ||
849 | if (count > FTABSIZ) | |
850 | { /* limit logging rate so syslog isn't DOSed either */ | |
851 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
852 | { | |
853 | warntime = now; | |
854 | syslog(LOG_WARNING, "forwarding table overflow: check for server loops."); | |
855 | } | |
856 | return NULL; | |
857 | } | |
858 | ||
859 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
860 | { | |
861 | f->next = frec_list; | |
862 | f->time = now; | |
863 | frec_list = f; | |
864 | } | |
865 | return f; /* OK if malloc fails and this is NULL */ | |
866 | } | |
867 | ||
868 | static struct frec *lookup_frec(unsigned short id) | |
869 | { | |
870 | struct frec *f; | |
871 | ||
872 | for(f = frec_list; f; f = f->next) | |
873 | if (f->new_id == id) | |
874 | return f; | |
875 | ||
876 | return NULL; | |
877 | } | |
878 | ||
879 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
880 | union mysockaddr *addr, |
881 | unsigned int crc) | |
9e4abcb5 | 882 | { |
feba5c1d SK |
883 | struct frec *f; |
884 | ||
9e4abcb5 SK |
885 | for(f = frec_list; f; f = f->next) |
886 | if (f->new_id && | |
887 | f->orig_id == id && | |
fd9fa481 | 888 | f->crc == crc && |
9e4abcb5 SK |
889 | sockaddr_isequal(&f->source, addr)) |
890 | return f; | |
891 | ||
892 | return NULL; | |
893 | } | |
894 | ||
895 | ||
896 | /* return unique random ids between 1 and 65535 */ | |
897 | static unsigned short get_id(void) | |
898 | { | |
899 | unsigned short ret = 0; | |
900 | ||
901 | while (ret == 0) | |
902 | { | |
903 | ret = rand16(); | |
904 | ||
905 | /* scrap ids already in use */ | |
906 | if ((ret != 0) && lookup_frec(ret)) | |
907 | ret = 0; | |
908 | } | |
909 | ||
910 | return ret; | |
911 | } | |
912 | ||
913 | ||
914 | ||
915 | ||
916 |