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