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