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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 | |
3be34541 | 117 | unsigned short search_servers(struct daemon *daemon, struct all_addr **addrpp, |
feba5c1d SK |
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 | ||
3be34541 | 130 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d SK |
131 | /* domain matches take priority over NODOTS matches */ |
132 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.')) | |
133 | { | |
134 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
135 | *type = SERV_FOR_NODOTS; | |
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 | 183 | } |
3be34541 | 184 | else if (qtype && (daemon->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 */ |
3be34541 SK |
194 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
195 | struct all_addr *dst_addr, unsigned int dst_iface, | |
196 | HEADER *header, int plen, time_t now) | |
9e4abcb5 SK |
197 | { |
198 | struct frec *forward; | |
199 | char *domain = NULL; | |
de37951c | 200 | int forwardall = 0, type = 0; |
9e4abcb5 SK |
201 | struct all_addr *addrp = NULL; |
202 | unsigned short flags = 0; | |
3be34541 | 203 | unsigned short gotname = extract_request(header, (unsigned int)plen, daemon->namebuff, NULL); |
de37951c SK |
204 | struct server *start = NULL; |
205 | ||
9e4abcb5 | 206 | /* may be recursion not speced or no servers available. */ |
3be34541 | 207 | if (!header->rd || !daemon->servers) |
9e4abcb5 SK |
208 | forward = NULL; |
209 | else if ((forward = lookup_frec_by_sender(ntohs(header->id), udpaddr))) | |
210 | { | |
de37951c | 211 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 212 | domain = forward->sentto->domain; |
3be34541 | 213 | if (!(daemon->options & OPT_ORDER)) |
de37951c SK |
214 | { |
215 | forwardall = 1; | |
3be34541 | 216 | daemon->last_server = NULL; |
de37951c | 217 | } |
9e4abcb5 | 218 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 219 | if (!(start = forward->sentto->next)) |
3be34541 | 220 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
221 | header->id = htons(forward->new_id); |
222 | } | |
223 | else | |
224 | { | |
225 | if (gotname) | |
3be34541 | 226 | flags = search_servers(daemon, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 227 | |
feba5c1d SK |
228 | if (!flags && !(forward = get_new_frec(now))) |
229 | /* table full - server failure. */ | |
230 | flags = F_NEG; | |
9e4abcb5 SK |
231 | |
232 | if (forward) | |
233 | { | |
234 | /* In strict_order mode, or when using domain specific servers | |
235 | always try servers in the order specified in resolv.conf, | |
236 | otherwise, use the one last known to work. */ | |
237 | ||
3be34541 SK |
238 | if (type != 0 || (daemon->options & OPT_ORDER)) |
239 | start = daemon->servers; | |
240 | else if (!(start = daemon->last_server)) | |
de37951c | 241 | { |
3be34541 | 242 | start = daemon->servers; |
de37951c SK |
243 | forwardall = 1; |
244 | } | |
feba5c1d | 245 | |
9e4abcb5 | 246 | forward->source = *udpaddr; |
44a2a316 | 247 | forward->dest = *dst_addr; |
dfa666f2 | 248 | forward->iface = dst_iface; |
9e4abcb5 SK |
249 | forward->new_id = get_id(); |
250 | forward->fd = udpfd; | |
251 | forward->orig_id = ntohs(header->id); | |
252 | header->id = htons(forward->new_id); | |
253 | } | |
254 | } | |
feba5c1d | 255 | |
9e4abcb5 SK |
256 | /* check for send errors here (no route to host) |
257 | if we fail to send to all nameservers, send back an error | |
258 | packet straight away (helps modem users when offline) */ | |
259 | ||
260 | if (!flags && forward) | |
261 | { | |
de37951c SK |
262 | struct server *firstsentto = start; |
263 | int forwarded = 0; | |
264 | ||
9e4abcb5 SK |
265 | while (1) |
266 | { | |
9e4abcb5 SK |
267 | /* only send to servers dealing with our domain. |
268 | domain may be NULL, in which case server->domain | |
269 | must be NULL also. */ | |
270 | ||
de37951c SK |
271 | if (type == (start->flags & SERV_TYPE) && |
272 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain))) | |
9e4abcb5 | 273 | { |
feba5c1d SK |
274 | if (!(start->flags & SERV_LITERAL_ADDRESS) && |
275 | sendto(start->sfd->fd, (char *)header, plen, 0, | |
276 | &start->addr.sa, | |
277 | sa_len(&start->addr)) != -1) | |
9e4abcb5 | 278 | { |
de37951c | 279 | if (!gotname) |
3be34541 | 280 | strcpy(daemon->namebuff, "query"); |
de37951c | 281 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 282 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 283 | (struct all_addr *)&start->addr.in.sin_addr, 0); |
de37951c SK |
284 | #ifdef HAVE_IPV6 |
285 | else | |
3be34541 | 286 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 287 | (struct all_addr *)&start->addr.in6.sin6_addr, 0); |
de37951c SK |
288 | #endif |
289 | forwarded = 1; | |
290 | forward->sentto = start; | |
291 | if (!forwardall) | |
292 | break; | |
9e4abcb5 SK |
293 | } |
294 | } | |
295 | ||
de37951c | 296 | if (!(start = start->next)) |
3be34541 | 297 | start = daemon->servers; |
9e4abcb5 | 298 | |
de37951c | 299 | if (start == firstsentto) |
9e4abcb5 SK |
300 | break; |
301 | } | |
302 | ||
de37951c | 303 | if (forwarded) |
3be34541 | 304 | return; |
de37951c | 305 | |
9e4abcb5 SK |
306 | /* could not send on, prepare to return */ |
307 | header->id = htons(forward->orig_id); | |
308 | forward->new_id = 0; /* cancel */ | |
309 | } | |
310 | ||
311 | /* could not send on, return empty answer or address if known for whole domain */ | |
3be34541 SK |
312 | plen = setup_reply(header, (unsigned int)plen, addrp, flags, daemon->local_ttl); |
313 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
44a2a316 | 314 | |
3be34541 | 315 | return; |
9e4abcb5 SK |
316 | } |
317 | ||
3be34541 SK |
318 | static int process_reply(struct daemon *daemon, HEADER *header, time_t now, |
319 | union mysockaddr *serveraddr, int n) | |
feba5c1d SK |
320 | { |
321 | unsigned char *pheader; | |
322 | ||
323 | /* If upstream is advertising a larger UDP packet size | |
324 | than we allow, trim it so that we don't get overlarge | |
325 | requests for the client. */ | |
326 | ||
327 | if ((pheader = find_pseudoheader(header, n))) | |
328 | { | |
329 | unsigned short udpsz; | |
330 | unsigned char *psave = pheader; | |
331 | ||
332 | GETSHORT(udpsz, pheader); | |
3be34541 SK |
333 | if (udpsz > daemon->edns_pktsz) |
334 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
335 | } |
336 | ||
337 | /* Complain loudly if the upstream server is non-recursive. */ | |
338 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0) | |
339 | { | |
340 | char addrbuff[ADDRSTRLEN]; | |
341 | #ifdef HAVE_IPV6 | |
342 | if (serveraddr->sa.sa_family == AF_INET) | |
343 | inet_ntop(AF_INET, &serveraddr->in.sin_addr, addrbuff, ADDRSTRLEN); | |
344 | else if (serveraddr->sa.sa_family == AF_INET6) | |
345 | inet_ntop(AF_INET6, &serveraddr->in6.sin6_addr, addrbuff, ADDRSTRLEN); | |
346 | #else | |
347 | strcpy(addrbuff, inet_ntoa(serveraddr->in.sin_addr)); | |
348 | #endif | |
349 | syslog(LOG_WARNING, "nameserver %s refused to do a recursive query", addrbuff); | |
350 | return 0; | |
351 | } | |
352 | ||
353 | if ((header->rcode == NOERROR || header->rcode == NXDOMAIN) && header->opcode == QUERY) | |
354 | { | |
3be34541 | 355 | if (!(daemon->bogus_addr && |
feba5c1d | 356 | header->rcode == NOERROR && |
3be34541 | 357 | check_for_bogus_wildcard(header, (unsigned int)n, daemon->namebuff, daemon->bogus_addr, now))) |
feba5c1d SK |
358 | { |
359 | if (header->rcode == NOERROR && ntohs(header->ancount) != 0) | |
3be34541 SK |
360 | extract_addresses(header, (unsigned int)n, daemon->namebuff, now, daemon->doctors); |
361 | else if (!(daemon->options & OPT_NO_NEG)) | |
362 | extract_neg_addrs(header, (unsigned int)n, daemon->namebuff, now); | |
feba5c1d SK |
363 | } |
364 | } | |
365 | ||
366 | return 1; | |
367 | } | |
368 | ||
3be34541 SK |
369 | /* sets new last_server */ |
370 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
371 | { |
372 | /* packet from peer server, extract data for cache, and send to | |
373 | original requester */ | |
374 | struct frec *forward; | |
375 | HEADER *header; | |
de37951c SK |
376 | union mysockaddr serveraddr; |
377 | socklen_t addrlen = sizeof(serveraddr); | |
3be34541 | 378 | int n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
de37951c SK |
379 | |
380 | /* Determine the address of the server replying so that we can mark that as good */ | |
381 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
382 | #ifdef HAVE_IPV6 | |
383 | if (serveraddr.sa.sa_family == AF_INET6) | |
384 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
385 | #endif | |
9e4abcb5 | 386 | |
3be34541 | 387 | header = (HEADER *)daemon->packet; |
de37951c | 388 | if (n >= (int)sizeof(HEADER) && header->qr && (forward = lookup_frec(ntohs(header->id)))) |
9e4abcb5 | 389 | { |
de37951c SK |
390 | /* find good server by address if possible, otherwise assume the last one we sent to */ |
391 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
392 | { | |
3be34541 SK |
393 | struct server *last_server; |
394 | daemon->last_server = forward->sentto; | |
395 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
de37951c SK |
396 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && |
397 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
3be34541 SK |
398 | { |
399 | daemon->last_server = last_server; | |
400 | break; | |
401 | } | |
de37951c | 402 | } |
de37951c | 403 | |
3be34541 SK |
404 | if (process_reply(daemon, header, now, &serveraddr, n)) |
405 | { | |
406 | header->id = htons(forward->orig_id); | |
407 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, n, | |
408 | &forward->source, &forward->dest, forward->iface); | |
409 | forward->new_id = 0; /* cancel */ | |
410 | } | |
9e4abcb5 | 411 | } |
9e4abcb5 | 412 | } |
44a2a316 | 413 | |
3be34541 | 414 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 415 | { |
3be34541 | 416 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 417 | union mysockaddr source_addr; |
c1bb8504 | 418 | unsigned short type; |
44a2a316 SK |
419 | struct iname *tmp; |
420 | struct all_addr dst_addr; | |
3be34541 | 421 | int check_dst = !(daemon->options & OPT_NOWILD); |
8a911ccc | 422 | int m, n, if_index = 0; |
44a2a316 SK |
423 | struct iovec iov[1]; |
424 | struct msghdr msg; | |
425 | struct cmsghdr *cmptr; | |
44a2a316 SK |
426 | union { |
427 | struct cmsghdr align; /* this ensures alignment */ | |
428 | #ifdef HAVE_IPV6 | |
429 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
430 | #endif | |
431 | #if defined(IP_PKTINFO) | |
432 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
433 | #elif defined(IP_RECVDSTADDR) | |
434 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
435 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
436 | #endif | |
437 | } control_u; | |
438 | ||
3be34541 SK |
439 | iov[0].iov_base = daemon->packet; |
440 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
441 | |
442 | msg.msg_control = control_u.control; | |
443 | msg.msg_controllen = sizeof(control_u); | |
444 | msg.msg_flags = 0; | |
445 | msg.msg_name = &source_addr; | |
446 | msg.msg_namelen = sizeof(source_addr); | |
447 | msg.msg_iov = iov; | |
448 | msg.msg_iovlen = 1; | |
449 | ||
de37951c | 450 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 451 | return; |
44a2a316 SK |
452 | |
453 | source_addr.sa.sa_family = listen->family; | |
454 | #ifdef HAVE_IPV6 | |
455 | if (listen->family == AF_INET6) | |
feba5c1d SK |
456 | { |
457 | check_dst = 1; | |
458 | source_addr.in6.sin6_flowinfo = htonl(0); | |
459 | } | |
44a2a316 SK |
460 | #endif |
461 | ||
feba5c1d | 462 | if (check_dst && msg.msg_controllen < sizeof(struct cmsghdr)) |
3be34541 | 463 | return; |
44a2a316 SK |
464 | |
465 | #if defined(IP_PKTINFO) | |
feba5c1d | 466 | if (check_dst && listen->family == AF_INET) |
44a2a316 SK |
467 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
468 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
469 | { | |
470 | dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; | |
8a911ccc | 471 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
44a2a316 SK |
472 | } |
473 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
feba5c1d | 474 | if (check_dst && listen->family == AF_INET) |
44a2a316 SK |
475 | { |
476 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
477 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
8a911ccc | 478 | dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
44a2a316 | 479 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
8a911ccc | 480 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; |
44a2a316 SK |
481 | } |
482 | #endif | |
483 | ||
484 | #ifdef HAVE_IPV6 | |
feba5c1d | 485 | if (listen->family == AF_INET6) |
44a2a316 SK |
486 | { |
487 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
488 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
489 | { | |
490 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
8a911ccc | 491 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; |
44a2a316 SK |
492 | } |
493 | } | |
494 | #endif | |
495 | ||
496 | if (n < (int)sizeof(HEADER) || header->qr) | |
3be34541 | 497 | return; |
44a2a316 SK |
498 | |
499 | /* enforce available interface configuration */ | |
feba5c1d | 500 | if (check_dst) |
44a2a316 | 501 | { |
8a911ccc SK |
502 | struct ifreq ifr; |
503 | ||
504 | if (if_index == 0) | |
3be34541 | 505 | return; |
44a2a316 | 506 | |
3be34541 | 507 | if (daemon->if_except || daemon->if_names) |
8a911ccc SK |
508 | { |
509 | #ifdef SIOCGIFNAME | |
510 | ifr.ifr_ifindex = if_index; | |
511 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 512 | return; |
8a911ccc SK |
513 | #else |
514 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 515 | return; |
8a911ccc SK |
516 | #endif |
517 | } | |
518 | ||
3be34541 | 519 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 520 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 521 | return; |
9e4abcb5 | 522 | |
3be34541 | 523 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 524 | { |
3be34541 | 525 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 526 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
527 | break; |
528 | if (!tmp) | |
3be34541 | 529 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
530 | if (tmp->addr.sa.sa_family == listen->family) |
531 | { | |
532 | if (tmp->addr.sa.sa_family == AF_INET && | |
533 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
534 | break; | |
535 | #ifdef HAVE_IPV6 | |
536 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
537 | memcmp(&tmp->addr.in6.sin6_addr, | |
538 | &dst_addr.addr.addr6, | |
539 | sizeof(struct in6_addr)) == 0) | |
540 | break; | |
541 | #endif | |
542 | } | |
543 | if (!tmp) | |
3be34541 | 544 | return; |
44a2a316 SK |
545 | } |
546 | } | |
547 | ||
3be34541 | 548 | if (extract_request(header, (unsigned int)n, daemon->namebuff, &type)) |
44a2a316 SK |
549 | { |
550 | if (listen->family == AF_INET) | |
3be34541 | 551 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 552 | (struct all_addr *)&source_addr.in.sin_addr, type); |
44a2a316 SK |
553 | #ifdef HAVE_IPV6 |
554 | else | |
3be34541 | 555 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 556 | (struct all_addr *)&source_addr.in6.sin6_addr, type); |
44a2a316 SK |
557 | #endif |
558 | } | |
559 | ||
3be34541 | 560 | m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n, daemon, now); |
44a2a316 | 561 | if (m >= 1) |
3be34541 | 562 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 563 | else |
3be34541 SK |
564 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
565 | header, n, now); | |
44a2a316 SK |
566 | } |
567 | ||
feba5c1d SK |
568 | static int read_write(int fd, char *packet, int size, int rw) |
569 | { | |
570 | int n, done; | |
571 | ||
572 | for (done = 0; done < size; done += n) | |
573 | { | |
574 | retry: | |
575 | if (rw) | |
576 | n = read(fd, &packet[done], (size_t)(size - done)); | |
577 | else | |
578 | n = write(fd, &packet[done], (size_t)(size - done)); | |
579 | ||
580 | if (n == 0) | |
581 | return 0; | |
582 | else if (n == -1) | |
583 | { | |
584 | if (errno == EINTR) | |
585 | goto retry; | |
586 | else if (errno == EAGAIN) | |
587 | { | |
588 | struct timespec waiter; | |
589 | waiter.tv_sec = 0; | |
590 | waiter.tv_nsec = 10000; | |
591 | nanosleep(&waiter, NULL); | |
592 | goto retry; | |
593 | } | |
594 | else | |
595 | return 0; | |
596 | } | |
597 | } | |
598 | return 1; | |
599 | } | |
600 | ||
601 | /* The daemon forks before calling this: it should deal with one connection, | |
602 | blocking as neccessary, and then return. Note, need to be a bit careful | |
603 | about resources for debug mode, when the fork is suppressed: that's | |
604 | done by the caller. */ | |
3be34541 | 605 | char *tcp_request(struct daemon *daemon, int confd, time_t now) |
feba5c1d SK |
606 | { |
607 | int size = 0, m; | |
c1bb8504 | 608 | unsigned short qtype, gotname; |
feba5c1d SK |
609 | unsigned char c1, c2; |
610 | /* Max TCP packet + slop */ | |
611 | char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); | |
612 | HEADER *header; | |
3be34541 SK |
613 | struct server *last_server; |
614 | ||
feba5c1d SK |
615 | while (1) |
616 | { | |
617 | if (!packet || | |
618 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
619 | !(size = c1 << 8 | c2) || | |
620 | !read_write(confd, packet, size, 1)) | |
621 | return packet; | |
622 | ||
623 | if (size < (int)sizeof(HEADER)) | |
624 | continue; | |
625 | ||
626 | header = (HEADER *)packet; | |
627 | ||
3be34541 | 628 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
629 | { |
630 | union mysockaddr peer_addr; | |
631 | socklen_t peer_len = sizeof(union mysockaddr); | |
632 | ||
633 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
634 | { | |
635 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 636 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 637 | (struct all_addr *)&peer_addr.in.sin_addr, qtype); |
feba5c1d SK |
638 | #ifdef HAVE_IPV6 |
639 | else | |
3be34541 | 640 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 641 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype); |
feba5c1d SK |
642 | #endif |
643 | } | |
644 | } | |
645 | ||
646 | /* m > 0 if answered from cache */ | |
3be34541 | 647 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, now); |
feba5c1d SK |
648 | |
649 | if (m == 0) | |
650 | { | |
651 | unsigned short flags = 0; | |
feba5c1d SK |
652 | struct all_addr *addrp = NULL; |
653 | int type = 0; | |
654 | char *domain = NULL; | |
655 | ||
656 | if (gotname) | |
3be34541 | 657 | flags = search_servers(daemon, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 658 | |
3be34541 SK |
659 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
660 | last_server = daemon->servers; | |
661 | else | |
662 | last_server = daemon->last_server; | |
feba5c1d SK |
663 | |
664 | if (!flags && last_server) | |
665 | { | |
666 | struct server *firstsendto = NULL; | |
667 | ||
668 | /* Loop round available servers until we succeed in connecting to one. | |
669 | Note that this code subtley ensures that consecutive queries on this connection | |
670 | which can go to the same server, do so. */ | |
671 | while (1) | |
672 | { | |
673 | if (!firstsendto) | |
674 | firstsendto = last_server; | |
675 | else | |
676 | { | |
677 | if (!(last_server = last_server->next)) | |
3be34541 | 678 | last_server = daemon->servers; |
feba5c1d SK |
679 | |
680 | if (last_server == firstsendto) | |
681 | break; | |
682 | } | |
683 | ||
684 | /* server for wrong domain */ | |
685 | if (type != (last_server->flags & SERV_TYPE) || | |
686 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
687 | continue; | |
688 | ||
689 | if ((last_server->tcpfd == -1) && | |
690 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
691 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
692 | { | |
693 | close(last_server->tcpfd); | |
694 | last_server->tcpfd = -1; | |
695 | } | |
696 | ||
697 | if (last_server->tcpfd == -1) | |
698 | continue; | |
699 | ||
700 | c1 = size >> 8; | |
701 | c2 = size; | |
702 | ||
703 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
704 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
705 | !read_write(last_server->tcpfd, packet, size, 0) || | |
706 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
707 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
708 | { | |
709 | close(last_server->tcpfd); | |
710 | last_server->tcpfd = -1; | |
711 | continue; | |
712 | } | |
713 | ||
714 | m = (c1 << 8) | c2; | |
715 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
716 | return packet; | |
717 | ||
718 | if (!gotname) | |
3be34541 | 719 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 720 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 721 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 722 | (struct all_addr *)&last_server->addr.in.sin_addr, 0); |
feba5c1d SK |
723 | #ifdef HAVE_IPV6 |
724 | else | |
3be34541 | 725 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
c1bb8504 | 726 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0); |
feba5c1d SK |
727 | #endif |
728 | ||
729 | /* There's no point in updating the cache, since this process will exit and | |
730 | lose the information after one query. We make this call for the alias and | |
731 | bogus-nxdomain side-effects. */ | |
3be34541 | 732 | process_reply(daemon, header, now, &last_server->addr, m); |
feba5c1d SK |
733 | |
734 | break; | |
735 | } | |
736 | } | |
737 | ||
738 | /* In case of local answer or no connections made. */ | |
739 | if (m == 0) | |
3be34541 | 740 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
741 | } |
742 | ||
743 | c1 = m>>8; | |
744 | c2 = m; | |
745 | if (!read_write(confd, &c1, 1, 0) || | |
746 | !read_write(confd, &c2, 1, 0) || | |
747 | !read_write(confd, packet, m, 0)) | |
748 | return packet; | |
749 | } | |
750 | } | |
751 | ||
9e4abcb5 SK |
752 | static struct frec *get_new_frec(time_t now) |
753 | { | |
754 | struct frec *f = frec_list, *oldest = NULL; | |
755 | time_t oldtime = now; | |
756 | int count = 0; | |
757 | static time_t warntime = 0; | |
758 | ||
759 | while (f) | |
760 | { | |
761 | if (f->new_id == 0) | |
762 | { | |
763 | f->time = now; | |
764 | return f; | |
765 | } | |
766 | ||
767 | if (difftime(f->time, oldtime) <= 0) | |
768 | { | |
769 | oldtime = f->time; | |
770 | oldest = f; | |
771 | } | |
772 | ||
773 | count++; | |
774 | f = f->next; | |
775 | } | |
776 | ||
777 | /* can't find empty one, use oldest if there is one | |
778 | and it's older than timeout */ | |
779 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
780 | { | |
781 | oldest->time = now; | |
782 | return oldest; | |
783 | } | |
784 | ||
785 | if (count > FTABSIZ) | |
786 | { /* limit logging rate so syslog isn't DOSed either */ | |
787 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
788 | { | |
789 | warntime = now; | |
790 | syslog(LOG_WARNING, "forwarding table overflow: check for server loops."); | |
791 | } | |
792 | return NULL; | |
793 | } | |
794 | ||
795 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
796 | { | |
797 | f->next = frec_list; | |
798 | f->time = now; | |
799 | frec_list = f; | |
800 | } | |
801 | return f; /* OK if malloc fails and this is NULL */ | |
802 | } | |
803 | ||
804 | static struct frec *lookup_frec(unsigned short id) | |
805 | { | |
806 | struct frec *f; | |
807 | ||
808 | for(f = frec_list; f; f = f->next) | |
809 | if (f->new_id == id) | |
810 | return f; | |
811 | ||
812 | return NULL; | |
813 | } | |
814 | ||
815 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
816 | union mysockaddr *addr) | |
817 | { | |
feba5c1d SK |
818 | struct frec *f; |
819 | ||
9e4abcb5 SK |
820 | for(f = frec_list; f; f = f->next) |
821 | if (f->new_id && | |
822 | f->orig_id == id && | |
823 | sockaddr_isequal(&f->source, addr)) | |
824 | return f; | |
825 | ||
826 | return NULL; | |
827 | } | |
828 | ||
829 | ||
830 | /* return unique random ids between 1 and 65535 */ | |
831 | static unsigned short get_id(void) | |
832 | { | |
833 | unsigned short ret = 0; | |
834 | ||
835 | while (ret == 0) | |
836 | { | |
837 | ret = rand16(); | |
838 | ||
839 | /* scrap ids already in use */ | |
840 | if ((ret != 0) && lookup_frec(ret)) | |
841 | ret = 0; | |
842 | } | |
843 | ||
844 | return ret; | |
845 | } | |
846 | ||
847 | ||
848 | ||
849 | ||
850 |