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61744359 | 1 | /* dnsmasq is Copyright (c) 2000-2013 Simon Kelley |
9e4abcb5 SK |
2 | |
3 | This program is free software; you can redistribute it and/or modify | |
4 | it under the terms of the GNU General Public License as published by | |
824af85b SK |
5 | the Free Software Foundation; version 2 dated June, 1991, or |
6 | (at your option) version 3 dated 29 June, 2007. | |
7 | ||
9e4abcb5 SK |
8 | This program is distributed in the hope that it will be useful, |
9 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | GNU General Public License for more details. | |
824af85b | 12 | |
73a08a24 SK |
13 | You should have received a copy of the GNU General Public License |
14 | along with this program. If not, see <http://www.gnu.org/licenses/>. | |
9e4abcb5 SK |
15 | */ |
16 | ||
9e4abcb5 SK |
17 | #include "dnsmasq.h" |
18 | ||
832af0ba | 19 | static struct frec *lookup_frec(unsigned short id, unsigned int crc); |
9e4abcb5 | 20 | static struct frec *lookup_frec_by_sender(unsigned short id, |
fd9fa481 SK |
21 | union mysockaddr *addr, |
22 | unsigned int crc); | |
316e2730 | 23 | static unsigned short get_id(unsigned int crc); |
1a6bca81 SK |
24 | static void free_frec(struct frec *f); |
25 | static struct randfd *allocate_rfd(int family); | |
9e4abcb5 | 26 | |
824af85b | 27 | /* Send a UDP packet with its source address set as "source" |
44a2a316 | 28 | unless nowild is true, when we just send it with the kernel default */ |
29689cfa SK |
29 | int send_from(int fd, int nowild, char *packet, size_t len, |
30 | union mysockaddr *to, struct all_addr *source, | |
50303b19 | 31 | unsigned int iface) |
9e4abcb5 | 32 | { |
44a2a316 SK |
33 | struct msghdr msg; |
34 | struct iovec iov[1]; | |
44a2a316 SK |
35 | union { |
36 | struct cmsghdr align; /* this ensures alignment */ | |
5e9e0efb | 37 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 SK |
38 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
39 | #elif defined(IP_SENDSRCADDR) | |
40 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
41 | #endif | |
42 | #ifdef HAVE_IPV6 | |
43 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
44 | #endif | |
45 | } control_u; | |
feba5c1d | 46 | |
44a2a316 SK |
47 | iov[0].iov_base = packet; |
48 | iov[0].iov_len = len; | |
49 | ||
feba5c1d SK |
50 | msg.msg_control = NULL; |
51 | msg.msg_controllen = 0; | |
44a2a316 SK |
52 | msg.msg_flags = 0; |
53 | msg.msg_name = to; | |
54 | msg.msg_namelen = sa_len(to); | |
55 | msg.msg_iov = iov; | |
56 | msg.msg_iovlen = 1; | |
feba5c1d | 57 | |
26128d27 | 58 | if (!nowild) |
44a2a316 | 59 | { |
26128d27 | 60 | struct cmsghdr *cmptr; |
feba5c1d SK |
61 | msg.msg_control = &control_u; |
62 | msg.msg_controllen = sizeof(control_u); | |
26128d27 SK |
63 | cmptr = CMSG_FIRSTHDR(&msg); |
64 | ||
65 | if (to->sa.sa_family == AF_INET) | |
66 | { | |
5e9e0efb | 67 | #if defined(HAVE_LINUX_NETWORK) |
8ef5ada2 SK |
68 | struct in_pktinfo p; |
69 | p.ipi_ifindex = 0; | |
70 | p.ipi_spec_dst = source->addr.addr4; | |
71 | memcpy(CMSG_DATA(cmptr), &p, sizeof(p)); | |
26128d27 | 72 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); |
c72daea8 | 73 | cmptr->cmsg_level = IPPROTO_IP; |
26128d27 | 74 | cmptr->cmsg_type = IP_PKTINFO; |
44a2a316 | 75 | #elif defined(IP_SENDSRCADDR) |
8ef5ada2 | 76 | memcpy(CMSG_DATA(cmptr), &(source->addr.addr4), sizeof(source->addr.addr4)); |
26128d27 SK |
77 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); |
78 | cmptr->cmsg_level = IPPROTO_IP; | |
79 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 80 | #endif |
26128d27 | 81 | } |
26128d27 | 82 | else |
b8187c80 | 83 | #ifdef HAVE_IPV6 |
26128d27 | 84 | { |
8ef5ada2 SK |
85 | struct in6_pktinfo p; |
86 | p.ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
87 | p.ipi6_addr = source->addr.addr6; | |
88 | memcpy(CMSG_DATA(cmptr), &p, sizeof(p)); | |
26128d27 | 89 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); |
316e2730 | 90 | cmptr->cmsg_type = daemon->v6pktinfo; |
c72daea8 | 91 | cmptr->cmsg_level = IPPROTO_IPV6; |
26128d27 | 92 | } |
3d8df260 | 93 | #else |
c72daea8 | 94 | (void)iface; /* eliminate warning */ |
44a2a316 | 95 | #endif |
26128d27 | 96 | } |
feba5c1d | 97 | |
29d28dda | 98 | while (sendmsg(fd, &msg, 0) == -1) |
feba5c1d | 99 | { |
fd9fa481 | 100 | if (retry_send()) |
29d28dda | 101 | continue; |
22d904db | 102 | |
29d28dda SK |
103 | /* If interface is still in DAD, EINVAL results - ignore that. */ |
104 | if (errno == EINVAL) | |
105 | break; | |
29689cfa | 106 | |
29d28dda | 107 | my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno)); |
29689cfa | 108 | return 0; |
feba5c1d | 109 | } |
29d28dda | 110 | |
29689cfa | 111 | return 1; |
9e4abcb5 | 112 | } |
44a2a316 | 113 | |
28866e95 SK |
114 | static unsigned int search_servers(time_t now, struct all_addr **addrpp, |
115 | unsigned int qtype, char *qdomain, int *type, char **domain, int *norebind) | |
feba5c1d SK |
116 | |
117 | { | |
118 | /* If the query ends in the domain in one of our servers, set | |
119 | domain to point to that name. We find the largest match to allow both | |
120 | domain.org and sub.domain.org to exist. */ | |
121 | ||
122 | unsigned int namelen = strlen(qdomain); | |
123 | unsigned int matchlen = 0; | |
124 | struct server *serv; | |
28866e95 | 125 | unsigned int flags = 0; |
feba5c1d | 126 | |
3be34541 | 127 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 128 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 129 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d | 130 | { |
28866e95 | 131 | unsigned int sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; |
feba5c1d | 132 | *type = SERV_FOR_NODOTS; |
feba5c1d | 133 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
134 | flags = F_NXDOMAIN; |
135 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
136 | { | |
137 | if (sflag & qtype) | |
138 | { | |
139 | flags = sflag; | |
140 | if (serv->addr.sa.sa_family == AF_INET) | |
141 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 142 | #ifdef HAVE_IPV6 |
36717eee SK |
143 | else |
144 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 145 | #endif |
36717eee | 146 | } |
824af85b | 147 | else if (!flags || (flags & F_NXDOMAIN)) |
36717eee SK |
148 | flags = F_NOERR; |
149 | } | |
feba5c1d SK |
150 | } |
151 | else if (serv->flags & SERV_HAS_DOMAIN) | |
152 | { | |
153 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 154 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 155 | if (namelen >= domainlen && |
b8187c80 | 156 | hostname_isequal(matchstart, serv->domain) && |
8ef5ada2 | 157 | (domainlen == 0 || namelen == domainlen || *(matchstart-1) == '.' )) |
feba5c1d | 158 | { |
8ef5ada2 SK |
159 | if (serv->flags & SERV_NO_REBIND) |
160 | *norebind = 1; | |
28866e95 | 161 | else |
feba5c1d | 162 | { |
28866e95 SK |
163 | unsigned int sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; |
164 | /* implement priority rules for --address and --server for same domain. | |
165 | --address wins if the address is for the correct AF | |
166 | --server wins otherwise. */ | |
167 | if (domainlen != 0 && domainlen == matchlen) | |
36717eee | 168 | { |
28866e95 | 169 | if ((serv->flags & SERV_LITERAL_ADDRESS)) |
8ef5ada2 | 170 | { |
28866e95 SK |
171 | if (!(sflag & qtype) && flags == 0) |
172 | continue; | |
173 | } | |
174 | else | |
175 | { | |
176 | if (flags & (F_IPV4 | F_IPV6)) | |
177 | continue; | |
178 | } | |
179 | } | |
180 | ||
181 | if (domainlen >= matchlen) | |
182 | { | |
183 | *type = serv->flags & (SERV_HAS_DOMAIN | SERV_USE_RESOLV | SERV_NO_REBIND); | |
184 | *domain = serv->domain; | |
185 | matchlen = domainlen; | |
186 | if (serv->flags & SERV_NO_ADDR) | |
187 | flags = F_NXDOMAIN; | |
188 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
189 | { | |
190 | if (sflag & qtype) | |
191 | { | |
192 | flags = sflag; | |
193 | if (serv->addr.sa.sa_family == AF_INET) | |
194 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 195 | #ifdef HAVE_IPV6 |
28866e95 SK |
196 | else |
197 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 198 | #endif |
28866e95 SK |
199 | } |
200 | else if (!flags || (flags & F_NXDOMAIN)) | |
201 | flags = F_NOERR; | |
8ef5ada2 | 202 | } |
28866e95 SK |
203 | else |
204 | flags = 0; | |
205 | } | |
206 | } | |
8ef5ada2 | 207 | } |
feba5c1d | 208 | } |
8ef5ada2 | 209 | |
7de060b0 | 210 | if (flags == 0 && !(qtype & F_QUERY) && |
28866e95 | 211 | option_bool(OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
7de060b0 SK |
212 | /* don't forward A or AAAA queries for simple names, except the empty name */ |
213 | flags = F_NOERR; | |
8ef5ada2 | 214 | |
5aabfc78 | 215 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now)) |
c1bb8504 | 216 | flags = F_NOERR; |
feba5c1d | 217 | |
824af85b SK |
218 | if (flags) |
219 | { | |
220 | int logflags = 0; | |
221 | ||
222 | if (flags == F_NXDOMAIN || flags == F_NOERR) | |
223 | logflags = F_NEG | qtype; | |
224 | ||
1a6bca81 | 225 | log_query(logflags | flags | F_CONFIG | F_FORWARD, qdomain, *addrpp, NULL); |
824af85b | 226 | } |
8ef5ada2 SK |
227 | else if ((*type) & SERV_USE_RESOLV) |
228 | { | |
229 | *type = 0; /* use normal servers for this domain */ | |
230 | *domain = NULL; | |
231 | } | |
feba5c1d SK |
232 | return flags; |
233 | } | |
44a2a316 | 234 | |
824af85b SK |
235 | static int forward_query(int udpfd, union mysockaddr *udpaddr, |
236 | struct all_addr *dst_addr, unsigned int dst_iface, | |
572b41eb | 237 | struct dns_header *header, size_t plen, time_t now, struct frec *forward) |
9e4abcb5 | 238 | { |
9e4abcb5 | 239 | char *domain = NULL; |
8ef5ada2 | 240 | int type = 0, norebind = 0; |
9e4abcb5 | 241 | struct all_addr *addrp = NULL; |
cdeda28f | 242 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
28866e95 SK |
243 | unsigned int flags = 0; |
244 | unsigned int gotname = extract_request(header, plen, daemon->namebuff, NULL); | |
de37951c | 245 | struct server *start = NULL; |
7de060b0 | 246 | |
28866e95 | 247 | /* RFC 4035: sect 4.6 para 2 */ |
572b41eb SK |
248 | header->hb4 &= ~HB4_AD; |
249 | ||
3d8df260 SK |
250 | /* may be no servers available. */ |
251 | if (!daemon->servers) | |
9e4abcb5 | 252 | forward = NULL; |
b8187c80 | 253 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 254 | { |
de37951c | 255 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 256 | domain = forward->sentto->domain; |
824af85b | 257 | forward->sentto->failed_queries++; |
28866e95 | 258 | if (!option_bool(OPT_ORDER)) |
de37951c | 259 | { |
0a852541 | 260 | forward->forwardall = 1; |
3be34541 | 261 | daemon->last_server = NULL; |
de37951c | 262 | } |
9e4abcb5 | 263 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 264 | if (!(start = forward->sentto->next)) |
3be34541 | 265 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
266 | header->id = htons(forward->new_id); |
267 | } | |
268 | else | |
269 | { | |
270 | if (gotname) | |
8ef5ada2 | 271 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind); |
9e4abcb5 | 272 | |
5aabfc78 | 273 | if (!flags && !(forward = get_new_frec(now, NULL))) |
feba5c1d SK |
274 | /* table full - server failure. */ |
275 | flags = F_NEG; | |
9e4abcb5 SK |
276 | |
277 | if (forward) | |
278 | { | |
0a852541 SK |
279 | forward->source = *udpaddr; |
280 | forward->dest = *dst_addr; | |
281 | forward->iface = dst_iface; | |
0a852541 | 282 | forward->orig_id = ntohs(header->id); |
316e2730 | 283 | forward->new_id = get_id(crc); |
832af0ba | 284 | forward->fd = udpfd; |
0a852541 SK |
285 | forward->crc = crc; |
286 | forward->forwardall = 0; | |
28866e95 SK |
287 | if (norebind) |
288 | forward->flags |= FREC_NOREBIND; | |
572b41eb | 289 | if (header->hb4 & HB4_CD) |
28866e95 | 290 | forward->flags |= FREC_CHECKING_DISABLED; |
0a852541 | 291 | |
28866e95 SK |
292 | header->id = htons(forward->new_id); |
293 | ||
8ef5ada2 SK |
294 | /* In strict_order mode, always try servers in the order |
295 | specified in resolv.conf, if a domain is given | |
296 | always try all the available servers, | |
9e4abcb5 SK |
297 | otherwise, use the one last known to work. */ |
298 | ||
8ef5ada2 SK |
299 | if (type == 0) |
300 | { | |
28866e95 | 301 | if (option_bool(OPT_ORDER)) |
8ef5ada2 SK |
302 | start = daemon->servers; |
303 | else if (!(start = daemon->last_server) || | |
304 | daemon->forwardcount++ > FORWARD_TEST || | |
305 | difftime(now, daemon->forwardtime) > FORWARD_TIME) | |
306 | { | |
307 | start = daemon->servers; | |
308 | forward->forwardall = 1; | |
309 | daemon->forwardcount = 0; | |
310 | daemon->forwardtime = now; | |
311 | } | |
312 | } | |
313 | else | |
de37951c | 314 | { |
3be34541 | 315 | start = daemon->servers; |
28866e95 | 316 | if (!option_bool(OPT_ORDER)) |
8ef5ada2 | 317 | forward->forwardall = 1; |
de37951c | 318 | } |
9e4abcb5 SK |
319 | } |
320 | } | |
feba5c1d | 321 | |
9e4abcb5 SK |
322 | /* check for send errors here (no route to host) |
323 | if we fail to send to all nameservers, send back an error | |
324 | packet straight away (helps modem users when offline) */ | |
325 | ||
326 | if (!flags && forward) | |
327 | { | |
de37951c SK |
328 | struct server *firstsentto = start; |
329 | int forwarded = 0; | |
28866e95 | 330 | |
797a7afb GT |
331 | if (option_bool(OPT_ADD_MAC)) |
332 | plen = add_mac(header, plen, ((char *) header) + PACKETSZ, &forward->source); | |
28866e95 | 333 | |
9e4abcb5 SK |
334 | while (1) |
335 | { | |
9e4abcb5 SK |
336 | /* only send to servers dealing with our domain. |
337 | domain may be NULL, in which case server->domain | |
338 | must be NULL also. */ | |
339 | ||
de37951c | 340 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
341 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
342 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 343 | { |
1a6bca81 SK |
344 | int fd; |
345 | ||
346 | /* find server socket to use, may need to get random one. */ | |
347 | if (start->sfd) | |
348 | fd = start->sfd->fd; | |
349 | else | |
350 | { | |
351 | #ifdef HAVE_IPV6 | |
352 | if (start->addr.sa.sa_family == AF_INET6) | |
353 | { | |
354 | if (!forward->rfd6 && | |
355 | !(forward->rfd6 = allocate_rfd(AF_INET6))) | |
356 | break; | |
3927da46 | 357 | daemon->rfd_save = forward->rfd6; |
1a6bca81 SK |
358 | fd = forward->rfd6->fd; |
359 | } | |
360 | else | |
361 | #endif | |
362 | { | |
363 | if (!forward->rfd4 && | |
364 | !(forward->rfd4 = allocate_rfd(AF_INET))) | |
365 | break; | |
3927da46 | 366 | daemon->rfd_save = forward->rfd4; |
1a6bca81 SK |
367 | fd = forward->rfd4->fd; |
368 | } | |
7de060b0 SK |
369 | |
370 | #ifdef HAVE_CONNTRACK | |
371 | /* Copy connection mark of incoming query to outgoing connection. */ | |
372 | if (option_bool(OPT_CONNTRACK)) | |
373 | { | |
374 | unsigned int mark; | |
797a7afb | 375 | if (get_incoming_mark(&forward->source, &forward->dest, 0, &mark)) |
7de060b0 SK |
376 | setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int)); |
377 | } | |
378 | #endif | |
1a6bca81 SK |
379 | } |
380 | ||
381 | if (sendto(fd, (char *)header, plen, 0, | |
feba5c1d | 382 | &start->addr.sa, |
fd9fa481 SK |
383 | sa_len(&start->addr)) == -1) |
384 | { | |
385 | if (retry_send()) | |
386 | continue; | |
387 | } | |
388 | else | |
9e4abcb5 | 389 | { |
cdeda28f SK |
390 | /* Keep info in case we want to re-send this packet */ |
391 | daemon->srv_save = start; | |
392 | daemon->packet_len = plen; | |
393 | ||
de37951c | 394 | if (!gotname) |
3be34541 | 395 | strcpy(daemon->namebuff, "query"); |
de37951c | 396 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 397 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 398 | (struct all_addr *)&start->addr.in.sin_addr, NULL); |
de37951c SK |
399 | #ifdef HAVE_IPV6 |
400 | else | |
3be34541 | 401 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 402 | (struct all_addr *)&start->addr.in6.sin6_addr, NULL); |
de37951c | 403 | #endif |
824af85b | 404 | start->queries++; |
de37951c SK |
405 | forwarded = 1; |
406 | forward->sentto = start; | |
0a852541 | 407 | if (!forward->forwardall) |
de37951c | 408 | break; |
0a852541 | 409 | forward->forwardall++; |
9e4abcb5 SK |
410 | } |
411 | } | |
412 | ||
de37951c | 413 | if (!(start = start->next)) |
3be34541 | 414 | start = daemon->servers; |
9e4abcb5 | 415 | |
de37951c | 416 | if (start == firstsentto) |
9e4abcb5 SK |
417 | break; |
418 | } | |
419 | ||
de37951c | 420 | if (forwarded) |
824af85b | 421 | return 1; |
de37951c | 422 | |
9e4abcb5 SK |
423 | /* could not send on, prepare to return */ |
424 | header->id = htons(forward->orig_id); | |
1a6bca81 | 425 | free_frec(forward); /* cancel */ |
9e4abcb5 SK |
426 | } |
427 | ||
428 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
429 | if (udpfd != -1) |
430 | { | |
cdeda28f | 431 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
54dd393f | 432 | send_from(udpfd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), (char *)header, plen, udpaddr, dst_addr, dst_iface); |
b8187c80 SK |
433 | } |
434 | ||
824af85b | 435 | return 0; |
9e4abcb5 SK |
436 | } |
437 | ||
572b41eb | 438 | static size_t process_reply(struct dns_header *header, time_t now, |
28866e95 | 439 | struct server *server, size_t n, int check_rebind, int checking_disabled) |
feba5c1d | 440 | { |
36717eee | 441 | unsigned char *pheader, *sizep; |
13d86c73 | 442 | char **sets = 0; |
832af0ba | 443 | int munged = 0, is_sign; |
cdeda28f SK |
444 | size_t plen; |
445 | ||
13d86c73 JD |
446 | #ifdef HAVE_IPSET |
447 | /* Similar algorithm to search_servers. */ | |
448 | struct ipsets *ipset_pos; | |
449 | unsigned int namelen = strlen(daemon->namebuff); | |
450 | unsigned int matchlen = 0; | |
451 | for (ipset_pos = daemon->ipsets; ipset_pos; ipset_pos = ipset_pos->next) | |
452 | { | |
453 | unsigned int domainlen = strlen(ipset_pos->domain); | |
454 | char *matchstart = daemon->namebuff + namelen - domainlen; | |
455 | if (namelen >= domainlen && hostname_isequal(matchstart, ipset_pos->domain) && | |
456 | (domainlen == 0 || namelen == domainlen || *(matchstart - 1) == '.' ) && | |
457 | domainlen >= matchlen) { | |
458 | matchlen = domainlen; | |
459 | sets = ipset_pos->sets; | |
460 | } | |
461 | } | |
462 | #endif | |
463 | ||
feba5c1d | 464 | /* If upstream is advertising a larger UDP packet size |
9009d746 SK |
465 | than we allow, trim it so that we don't get overlarge |
466 | requests for the client. We can't do this for signed packets. */ | |
feba5c1d | 467 | |
832af0ba | 468 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign)) && !is_sign) |
feba5c1d SK |
469 | { |
470 | unsigned short udpsz; | |
36717eee | 471 | unsigned char *psave = sizep; |
feba5c1d | 472 | |
36717eee | 473 | GETSHORT(udpsz, sizep); |
3be34541 SK |
474 | if (udpsz > daemon->edns_pktsz) |
475 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
476 | } |
477 | ||
28866e95 SK |
478 | /* RFC 4035 sect 4.6 para 3 */ |
479 | if (!is_sign && !option_bool(OPT_DNSSEC)) | |
572b41eb | 480 | header->hb4 &= ~HB4_AD; |
28866e95 | 481 | |
572b41eb | 482 | if (OPCODE(header) != QUERY || (RCODE(header) != NOERROR && RCODE(header) != NXDOMAIN)) |
0a852541 SK |
483 | return n; |
484 | ||
feba5c1d | 485 | /* Complain loudly if the upstream server is non-recursive. */ |
572b41eb | 486 | if (!(header->hb4 & HB4_RA) && RCODE(header) == NOERROR && ntohs(header->ancount) == 0 && |
0a852541 | 487 | server && !(server->flags & SERV_WARNED_RECURSIVE)) |
feba5c1d | 488 | { |
3d8df260 | 489 | prettyprint_addr(&server->addr, daemon->namebuff); |
f2621c7f | 490 | my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
28866e95 | 491 | if (!option_bool(OPT_LOG)) |
0a852541 SK |
492 | server->flags |= SERV_WARNED_RECURSIVE; |
493 | } | |
494 | ||
572b41eb | 495 | if (daemon->bogus_addr && RCODE(header) != NXDOMAIN && |
fd9fa481 | 496 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) |
feba5c1d | 497 | { |
fd9fa481 | 498 | munged = 1; |
572b41eb SK |
499 | SET_RCODE(header, NXDOMAIN); |
500 | header->hb3 &= ~HB3_AA; | |
36717eee | 501 | } |
fd9fa481 | 502 | else |
36717eee | 503 | { |
572b41eb | 504 | if (RCODE(header) == NXDOMAIN && |
fd9fa481 | 505 | extract_request(header, n, daemon->namebuff, NULL) && |
5aabfc78 | 506 | check_for_local_domain(daemon->namebuff, now)) |
36717eee SK |
507 | { |
508 | /* if we forwarded a query for a locally known name (because it was for | |
509 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
510 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 | 511 | munged = 1; |
572b41eb SK |
512 | header->hb3 |= HB3_AA; |
513 | SET_RCODE(header, NOERROR); | |
feba5c1d | 514 | } |
832af0ba | 515 | |
13d86c73 | 516 | if (extract_addresses(header, n, daemon->namebuff, now, sets, is_sign, check_rebind, checking_disabled)) |
824af85b | 517 | { |
8ef5ada2 | 518 | my_syslog(LOG_WARNING, _("possible DNS-rebind attack detected: %s"), daemon->namebuff); |
824af85b SK |
519 | munged = 1; |
520 | } | |
feba5c1d | 521 | } |
fd9fa481 SK |
522 | |
523 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
524 | nameserver info. */ | |
525 | ||
526 | if (munged) | |
527 | { | |
528 | header->ancount = htons(0); | |
529 | header->nscount = htons(0); | |
530 | header->arcount = htons(0); | |
531 | } | |
532 | ||
36717eee SK |
533 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
534 | sections of the packet. Find the new length here and put back pseudoheader | |
535 | if it was removed. */ | |
536 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
537 | } |
538 | ||
3be34541 | 539 | /* sets new last_server */ |
1a6bca81 | 540 | void reply_query(int fd, int family, time_t now) |
9e4abcb5 SK |
541 | { |
542 | /* packet from peer server, extract data for cache, and send to | |
543 | original requester */ | |
572b41eb | 544 | struct dns_header *header; |
de37951c | 545 | union mysockaddr serveraddr; |
832af0ba | 546 | struct frec *forward; |
de37951c | 547 | socklen_t addrlen = sizeof(serveraddr); |
1a6bca81 | 548 | ssize_t n = recvfrom(fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
cdeda28f | 549 | size_t nn; |
1a6bca81 SK |
550 | struct server *server; |
551 | ||
cdeda28f SK |
552 | /* packet buffer overwritten */ |
553 | daemon->srv_save = NULL; | |
832af0ba | 554 | |
de37951c | 555 | /* Determine the address of the server replying so that we can mark that as good */ |
1a6bca81 | 556 | serveraddr.sa.sa_family = family; |
de37951c SK |
557 | #ifdef HAVE_IPV6 |
558 | if (serveraddr.sa.sa_family == AF_INET6) | |
5e9e0efb | 559 | serveraddr.in6.sin6_flowinfo = 0; |
de37951c | 560 | #endif |
9e4abcb5 | 561 | |
1a6bca81 SK |
562 | /* spoof check: answer must come from known server, */ |
563 | for (server = daemon->servers; server; server = server->next) | |
564 | if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR)) && | |
565 | sockaddr_isequal(&server->addr, &serveraddr)) | |
566 | break; | |
567 | ||
572b41eb | 568 | header = (struct dns_header *)daemon->packet; |
fd9fa481 | 569 | |
1a6bca81 | 570 | if (!server || |
572b41eb | 571 | n < (int)sizeof(struct dns_header) || !(header->hb3 & HB3_QR) || |
1a6bca81 SK |
572 | !(forward = lookup_frec(ntohs(header->id), questions_crc(header, n, daemon->namebuff)))) |
573 | return; | |
574 | ||
575 | server = forward->sentto; | |
576 | ||
572b41eb | 577 | if ((RCODE(header) == SERVFAIL || RCODE(header) == REFUSED) && |
28866e95 | 578 | !option_bool(OPT_ORDER) && |
1a6bca81 SK |
579 | forward->forwardall == 0) |
580 | /* for broken servers, attempt to send to another one. */ | |
9e4abcb5 | 581 | { |
1a6bca81 SK |
582 | unsigned char *pheader; |
583 | size_t plen; | |
584 | int is_sign; | |
832af0ba | 585 | |
1a6bca81 SK |
586 | /* recreate query from reply */ |
587 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign); | |
588 | if (!is_sign) | |
832af0ba | 589 | { |
1a6bca81 SK |
590 | header->ancount = htons(0); |
591 | header->nscount = htons(0); | |
592 | header->arcount = htons(0); | |
593 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) | |
832af0ba | 594 | { |
572b41eb | 595 | header->hb3 &= ~(HB3_QR | HB3_TC); |
1a6bca81 SK |
596 | forward_query(-1, NULL, NULL, 0, header, nn, now, forward); |
597 | return; | |
832af0ba | 598 | } |
832af0ba | 599 | } |
1a6bca81 SK |
600 | } |
601 | ||
602 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
603 | { | |
572b41eb | 604 | if (RCODE(header) == SERVFAIL || RCODE(header) == REFUSED) |
1a6bca81 SK |
605 | server = NULL; |
606 | else | |
b8187c80 | 607 | { |
1a6bca81 SK |
608 | struct server *last_server; |
609 | ||
610 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
611 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
612 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
613 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
614 | { | |
615 | server = last_server; | |
616 | break; | |
617 | } | |
618 | } | |
28866e95 | 619 | if (!option_bool(OPT_ALL_SERVERS)) |
1a6bca81 SK |
620 | daemon->last_server = server; |
621 | } | |
622 | ||
623 | /* If the answer is an error, keep the forward record in place in case | |
624 | we get a good reply from another server. Kill it when we've | |
625 | had replies from all to avoid filling the forwarding table when | |
626 | everything is broken */ | |
627 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
572b41eb | 628 | (RCODE(header) != REFUSED && RCODE(header) != SERVFAIL)) |
1a6bca81 | 629 | { |
28866e95 | 630 | int check_rebind = !(forward->flags & FREC_NOREBIND); |
8ef5ada2 | 631 | |
28866e95 | 632 | if (!option_bool(OPT_NO_REBIND)) |
8ef5ada2 SK |
633 | check_rebind = 0; |
634 | ||
28866e95 | 635 | if ((nn = process_reply(header, now, server, (size_t)n, check_rebind, forward->flags & FREC_CHECKING_DISABLED))) |
1a6bca81 SK |
636 | { |
637 | header->id = htons(forward->orig_id); | |
572b41eb | 638 | header->hb4 |= HB4_RA; /* recursion if available */ |
54dd393f | 639 | send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn, |
50303b19 | 640 | &forward->source, &forward->dest, forward->iface); |
b8187c80 | 641 | } |
1a6bca81 | 642 | free_frec(forward); /* cancel */ |
9e4abcb5 | 643 | } |
9e4abcb5 | 644 | } |
44a2a316 | 645 | |
1a6bca81 | 646 | |
5aabfc78 | 647 | void receive_query(struct listener *listen, time_t now) |
44a2a316 | 648 | { |
572b41eb | 649 | struct dns_header *header = (struct dns_header *)daemon->packet; |
44a2a316 | 650 | union mysockaddr source_addr; |
c1bb8504 | 651 | unsigned short type; |
44a2a316 | 652 | struct all_addr dst_addr; |
f6b7dc47 | 653 | struct in_addr netmask, dst_addr_4; |
cdeda28f SK |
654 | size_t m; |
655 | ssize_t n; | |
656 | int if_index = 0; | |
4f7b304f | 657 | int auth_dns = 0; |
44a2a316 SK |
658 | struct iovec iov[1]; |
659 | struct msghdr msg; | |
660 | struct cmsghdr *cmptr; | |
44a2a316 SK |
661 | union { |
662 | struct cmsghdr align; /* this ensures alignment */ | |
663 | #ifdef HAVE_IPV6 | |
664 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
665 | #endif | |
5e9e0efb | 666 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 | 667 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
824af85b SK |
668 | #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK) |
669 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
670 | CMSG_SPACE(sizeof(unsigned int))]; | |
44a2a316 SK |
671 | #elif defined(IP_RECVDSTADDR) |
672 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
673 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
674 | #endif | |
675 | } control_u; | |
676 | ||
cdeda28f SK |
677 | /* packet buffer overwritten */ |
678 | daemon->srv_save = NULL; | |
679 | ||
4f7b304f SK |
680 | dst_addr_4.s_addr = 0; |
681 | netmask.s_addr = 0; | |
682 | ||
7e5664bd | 683 | if (option_bool(OPT_NOWILD) && listen->iface) |
3d8df260 | 684 | { |
4f7b304f SK |
685 | auth_dns = listen->iface->dns_auth; |
686 | ||
687 | if (listen->family == AF_INET) | |
688 | { | |
689 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
690 | netmask = listen->iface->netmask; | |
691 | } | |
3d8df260 | 692 | } |
4f7b304f | 693 | |
3be34541 SK |
694 | iov[0].iov_base = daemon->packet; |
695 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
696 | |
697 | msg.msg_control = control_u.control; | |
698 | msg.msg_controllen = sizeof(control_u); | |
699 | msg.msg_flags = 0; | |
700 | msg.msg_name = &source_addr; | |
701 | msg.msg_namelen = sizeof(source_addr); | |
702 | msg.msg_iov = iov; | |
703 | msg.msg_iovlen = 1; | |
704 | ||
de37951c | 705 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 706 | return; |
44a2a316 | 707 | |
572b41eb | 708 | if (n < (int)sizeof(struct dns_header) || |
5e9e0efb | 709 | (msg.msg_flags & MSG_TRUNC) || |
572b41eb | 710 | (header->hb3 & HB3_QR)) |
26128d27 SK |
711 | return; |
712 | ||
44a2a316 SK |
713 | source_addr.sa.sa_family = listen->family; |
714 | #ifdef HAVE_IPV6 | |
715 | if (listen->family == AF_INET6) | |
5e9e0efb | 716 | source_addr.in6.sin6_flowinfo = 0; |
44a2a316 | 717 | #endif |
28866e95 SK |
718 | |
719 | if (!option_bool(OPT_NOWILD)) | |
26128d27 SK |
720 | { |
721 | struct ifreq ifr; | |
722 | ||
723 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
724 | return; | |
44a2a316 | 725 | |
5e9e0efb | 726 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
727 | if (listen->family == AF_INET) |
728 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
c72daea8 | 729 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO) |
26128d27 | 730 | { |
8ef5ada2 SK |
731 | union { |
732 | unsigned char *c; | |
733 | struct in_pktinfo *p; | |
734 | } p; | |
735 | p.c = CMSG_DATA(cmptr); | |
736 | dst_addr_4 = dst_addr.addr.addr4 = p.p->ipi_spec_dst; | |
737 | if_index = p.p->ipi_ifindex; | |
26128d27 SK |
738 | } |
739 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
740 | if (listen->family == AF_INET) | |
44a2a316 | 741 | { |
26128d27 | 742 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
8ef5ada2 SK |
743 | { |
744 | union { | |
745 | unsigned char *c; | |
746 | unsigned int *i; | |
747 | struct in_addr *a; | |
748 | #ifndef HAVE_SOLARIS_NETWORK | |
749 | struct sockaddr_dl *s; | |
750 | #endif | |
751 | } p; | |
752 | p.c = CMSG_DATA(cmptr); | |
753 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
754 | dst_addr_4 = dst_addr.addr.addr4 = *(p.a); | |
755 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) | |
824af85b | 756 | #ifdef HAVE_SOLARIS_NETWORK |
8ef5ada2 | 757 | if_index = *(p.i); |
824af85b | 758 | #else |
8ef5ada2 | 759 | if_index = p.s->sdl_index; |
824af85b | 760 | #endif |
8ef5ada2 | 761 | } |
44a2a316 | 762 | } |
44a2a316 | 763 | #endif |
26128d27 | 764 | |
44a2a316 | 765 | #ifdef HAVE_IPV6 |
26128d27 SK |
766 | if (listen->family == AF_INET6) |
767 | { | |
768 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
c72daea8 | 769 | if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo) |
26128d27 | 770 | { |
8ef5ada2 SK |
771 | union { |
772 | unsigned char *c; | |
773 | struct in6_pktinfo *p; | |
774 | } p; | |
775 | p.c = CMSG_DATA(cmptr); | |
776 | ||
777 | dst_addr.addr.addr6 = p.p->ipi6_addr; | |
778 | if_index = p.p->ipi6_ifindex; | |
26128d27 SK |
779 | } |
780 | } | |
44a2a316 | 781 | #endif |
26128d27 SK |
782 | |
783 | /* enforce available interface configuration */ | |
784 | ||
e25db1f2 | 785 | if (!indextoname(listen->fd, if_index, ifr.ifr_name)) |
5e9e0efb | 786 | return; |
832af0ba | 787 | |
e25db1f2 SK |
788 | if (!iface_check(listen->family, &dst_addr, ifr.ifr_name, &auth_dns)) |
789 | { | |
790 | if (!option_bool(OPT_CLEVERBIND)) | |
791 | enumerate_interfaces(); | |
792 | if (!loopback_exception(listen->fd, listen->family, &dst_addr, ifr.ifr_name)) | |
793 | return; | |
794 | } | |
795 | ||
552af8b9 SK |
796 | if (listen->family == AF_INET && option_bool(OPT_LOCALISE)) |
797 | { | |
798 | struct irec *iface; | |
799 | ||
800 | /* get the netmask of the interface whch has the address we were sent to. | |
801 | This is no neccessarily the interface we arrived on. */ | |
802 | ||
803 | for (iface = daemon->interfaces; iface; iface = iface->next) | |
804 | if (iface->addr.sa.sa_family == AF_INET && | |
805 | iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr) | |
806 | break; | |
807 | ||
808 | /* interface may be new */ | |
e25db1f2 | 809 | if (!iface && !option_bool(OPT_CLEVERBIND)) |
552af8b9 SK |
810 | enumerate_interfaces(); |
811 | ||
812 | for (iface = daemon->interfaces; iface; iface = iface->next) | |
813 | if (iface->addr.sa.sa_family == AF_INET && | |
814 | iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr) | |
815 | break; | |
816 | ||
817 | /* If we failed, abandon localisation */ | |
818 | if (iface) | |
819 | netmask = iface->netmask; | |
820 | else | |
821 | dst_addr_4.s_addr = 0; | |
822 | } | |
44a2a316 SK |
823 | } |
824 | ||
cdeda28f | 825 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
44a2a316 | 826 | { |
1a6bca81 SK |
827 | char types[20]; |
828 | ||
4f7b304f | 829 | querystr(auth_dns ? "auth" : "query", types, type); |
1a6bca81 | 830 | |
44a2a316 | 831 | if (listen->family == AF_INET) |
3be34541 | 832 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 833 | (struct all_addr *)&source_addr.in.sin_addr, types); |
44a2a316 SK |
834 | #ifdef HAVE_IPV6 |
835 | else | |
3be34541 | 836 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 837 | (struct all_addr *)&source_addr.in6.sin6_addr, types); |
44a2a316 SK |
838 | #endif |
839 | } | |
840 | ||
4820dce9 | 841 | #ifdef HAVE_AUTH |
4f7b304f | 842 | if (auth_dns) |
824af85b | 843 | { |
49678767 | 844 | m = answer_auth(header, ((char *) header) + PACKETSZ, (size_t)n, now, &source_addr); |
4f7b304f SK |
845 | if (m >= 1) |
846 | send_from(listen->fd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), | |
847 | (char *)header, m, &source_addr, &dst_addr, if_index); | |
824af85b | 848 | } |
44a2a316 | 849 | else |
4820dce9 | 850 | #endif |
4f7b304f SK |
851 | { |
852 | m = answer_request(header, ((char *) header) + PACKETSZ, (size_t)n, | |
853 | dst_addr_4, netmask, now); | |
854 | ||
855 | if (m >= 1) | |
856 | { | |
857 | send_from(listen->fd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), | |
858 | (char *)header, m, &source_addr, &dst_addr, if_index); | |
859 | daemon->local_answer++; | |
860 | } | |
861 | else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index, | |
862 | header, (size_t)n, now, NULL)) | |
863 | daemon->queries_forwarded++; | |
864 | else | |
865 | daemon->local_answer++; | |
866 | } | |
44a2a316 SK |
867 | } |
868 | ||
feba5c1d SK |
869 | /* The daemon forks before calling this: it should deal with one connection, |
870 | blocking as neccessary, and then return. Note, need to be a bit careful | |
871 | about resources for debug mode, when the fork is suppressed: that's | |
872 | done by the caller. */ | |
5aabfc78 | 873 | unsigned char *tcp_request(int confd, time_t now, |
4f7b304f | 874 | union mysockaddr *local_addr, struct in_addr netmask, int auth_dns) |
feba5c1d | 875 | { |
28866e95 SK |
876 | size_t size = 0; |
877 | int norebind = 0; | |
878 | int checking_disabled; | |
cdeda28f | 879 | size_t m; |
ee86ce68 SK |
880 | unsigned short qtype; |
881 | unsigned int gotname; | |
feba5c1d | 882 | unsigned char c1, c2; |
4b5ea12e SK |
883 | /* Max TCP packet + slop + size */ |
884 | unsigned char *packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ + sizeof(u16)); | |
885 | unsigned char *payload = &packet[2]; | |
886 | /* largest field in header is 16-bits, so this is still sufficiently aligned */ | |
887 | struct dns_header *header = (struct dns_header *)payload; | |
888 | u16 *length = (u16 *)packet; | |
3be34541 | 889 | struct server *last_server; |
7de060b0 SK |
890 | struct in_addr dst_addr_4; |
891 | union mysockaddr peer_addr; | |
892 | socklen_t peer_len = sizeof(union mysockaddr); | |
3be34541 | 893 | |
7de060b0 SK |
894 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) == -1) |
895 | return packet; | |
896 | ||
feba5c1d SK |
897 | while (1) |
898 | { | |
899 | if (!packet || | |
900 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
901 | !(size = c1 << 8 | c2) || | |
4b5ea12e | 902 | !read_write(confd, payload, size, 1)) |
feba5c1d SK |
903 | return packet; |
904 | ||
572b41eb | 905 | if (size < (int)sizeof(struct dns_header)) |
feba5c1d SK |
906 | continue; |
907 | ||
28866e95 | 908 | /* save state of "cd" flag in query */ |
572b41eb | 909 | checking_disabled = header->hb4 & HB4_CD; |
28866e95 SK |
910 | |
911 | /* RFC 4035: sect 4.6 para 2 */ | |
572b41eb | 912 | header->hb4 &= ~HB4_AD; |
feba5c1d | 913 | |
3be34541 | 914 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d | 915 | { |
7de060b0 | 916 | char types[20]; |
feba5c1d | 917 | |
4f7b304f | 918 | querystr(auth_dns ? "auth" : "query", types, qtype); |
7de060b0 SK |
919 | |
920 | if (peer_addr.sa.sa_family == AF_INET) | |
921 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, | |
922 | (struct all_addr *)&peer_addr.in.sin_addr, types); | |
feba5c1d | 923 | #ifdef HAVE_IPV6 |
7de060b0 SK |
924 | else |
925 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, | |
926 | (struct all_addr *)&peer_addr.in6.sin6_addr, types); | |
feba5c1d | 927 | #endif |
feba5c1d SK |
928 | } |
929 | ||
7de060b0 SK |
930 | if (local_addr->sa.sa_family == AF_INET) |
931 | dst_addr_4 = local_addr->in.sin_addr; | |
932 | else | |
933 | dst_addr_4.s_addr = 0; | |
934 | ||
4820dce9 | 935 | #ifdef HAVE_AUTH |
4f7b304f | 936 | if (auth_dns) |
49678767 | 937 | m = answer_auth(header, ((char *) header) + 65536, (size_t)size, now, &peer_addr); |
4f7b304f | 938 | else |
4820dce9 | 939 | #endif |
feba5c1d | 940 | { |
4f7b304f SK |
941 | /* m > 0 if answered from cache */ |
942 | m = answer_request(header, ((char *) header) + 65536, (size_t)size, | |
943 | dst_addr_4, netmask, now); | |
feba5c1d | 944 | |
4f7b304f SK |
945 | /* Do this by steam now we're not in the select() loop */ |
946 | check_log_writer(NULL); | |
947 | ||
948 | if (m == 0) | |
feba5c1d | 949 | { |
4f7b304f SK |
950 | unsigned int flags = 0; |
951 | struct all_addr *addrp = NULL; | |
952 | int type = 0; | |
953 | char *domain = NULL; | |
feba5c1d | 954 | |
4f7b304f SK |
955 | if (option_bool(OPT_ADD_MAC)) |
956 | size = add_mac(header, size, ((char *) header) + 65536, &peer_addr); | |
957 | ||
958 | if (gotname) | |
959 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind); | |
960 | ||
961 | if (type != 0 || option_bool(OPT_ORDER) || !daemon->last_server) | |
962 | last_server = daemon->servers; | |
963 | else | |
964 | last_server = daemon->last_server; | |
965 | ||
966 | if (!flags && last_server) | |
967 | { | |
968 | struct server *firstsendto = NULL; | |
969 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); | |
970 | ||
971 | /* Loop round available servers until we succeed in connecting to one. | |
972 | Note that this code subtley ensures that consecutive queries on this connection | |
973 | which can go to the same server, do so. */ | |
974 | while (1) | |
feba5c1d | 975 | { |
4f7b304f SK |
976 | if (!firstsendto) |
977 | firstsendto = last_server; | |
978 | else | |
979 | { | |
980 | if (!(last_server = last_server->next)) | |
981 | last_server = daemon->servers; | |
982 | ||
983 | if (last_server == firstsendto) | |
984 | break; | |
985 | } | |
986 | ||
987 | /* server for wrong domain */ | |
988 | if (type != (last_server->flags & SERV_TYPE) || | |
989 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
7de060b0 SK |
990 | continue; |
991 | ||
4f7b304f | 992 | if (last_server->tcpfd == -1) |
7de060b0 | 993 | { |
4f7b304f SK |
994 | if ((last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) == -1) |
995 | continue; | |
996 | ||
997 | if ((!local_bind(last_server->tcpfd, &last_server->source_addr, last_server->interface, 1) || | |
998 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1)) | |
999 | { | |
1000 | close(last_server->tcpfd); | |
1001 | last_server->tcpfd = -1; | |
1002 | continue; | |
1003 | } | |
1004 | ||
7de060b0 | 1005 | #ifdef HAVE_CONNTRACK |
4f7b304f SK |
1006 | /* Copy connection mark of incoming query to outgoing connection. */ |
1007 | if (option_bool(OPT_CONNTRACK)) | |
1008 | { | |
1009 | unsigned int mark; | |
1010 | struct all_addr local; | |
7de060b0 | 1011 | #ifdef HAVE_IPV6 |
4f7b304f SK |
1012 | if (local_addr->sa.sa_family == AF_INET6) |
1013 | local.addr.addr6 = local_addr->in6.sin6_addr; | |
1014 | else | |
7de060b0 | 1015 | #endif |
4f7b304f SK |
1016 | local.addr.addr4 = local_addr->in.sin_addr; |
1017 | ||
1018 | if (get_incoming_mark(&peer_addr, &local, 1, &mark)) | |
1019 | setsockopt(last_server->tcpfd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int)); | |
1020 | } | |
7de060b0 | 1021 | #endif |
4f7b304f SK |
1022 | } |
1023 | ||
4b5ea12e | 1024 | *length = htons(size); |
4f7b304f | 1025 | |
4b5ea12e | 1026 | if (!read_write(last_server->tcpfd, packet, size + sizeof(u16), 0) || |
4f7b304f SK |
1027 | !read_write(last_server->tcpfd, &c1, 1, 1) || |
1028 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
1029 | { | |
1030 | close(last_server->tcpfd); | |
1031 | last_server->tcpfd = -1; | |
1032 | continue; | |
1033 | } | |
1034 | ||
1035 | m = (c1 << 8) | c2; | |
4b5ea12e | 1036 | if (!read_write(last_server->tcpfd, payload, m, 1)) |
4f7b304f SK |
1037 | return packet; |
1038 | ||
1039 | if (!gotname) | |
1040 | strcpy(daemon->namebuff, "query"); | |
1041 | if (last_server->addr.sa.sa_family == AF_INET) | |
1042 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, | |
1043 | (struct all_addr *)&last_server->addr.in.sin_addr, NULL); | |
feba5c1d | 1044 | #ifdef HAVE_IPV6 |
4f7b304f SK |
1045 | else |
1046 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, | |
1047 | (struct all_addr *)&last_server->addr.in6.sin6_addr, NULL); | |
feba5c1d | 1048 | #endif |
4f7b304f SK |
1049 | |
1050 | /* There's no point in updating the cache, since this process will exit and | |
1051 | lose the information after a few queries. We make this call for the alias and | |
1052 | bogus-nxdomain side-effects. */ | |
1053 | /* If the crc of the question section doesn't match the crc we sent, then | |
1054 | someone might be attempting to insert bogus values into the cache by | |
1055 | sending replies containing questions and bogus answers. */ | |
1056 | if (crc == questions_crc(header, (unsigned int)m, daemon->namebuff)) | |
1057 | m = process_reply(header, now, last_server, (unsigned int)m, | |
1058 | option_bool(OPT_NO_REBIND) && !norebind, checking_disabled); | |
1059 | ||
1060 | break; | |
1061 | } | |
feba5c1d | 1062 | } |
4f7b304f SK |
1063 | |
1064 | /* In case of local answer or no connections made. */ | |
1065 | if (m == 0) | |
1066 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); | |
feba5c1d | 1067 | } |
feba5c1d | 1068 | } |
4f7b304f | 1069 | |
5aabfc78 | 1070 | check_log_writer(NULL); |
feba5c1d | 1071 | |
4b5ea12e SK |
1072 | *length = htons(m); |
1073 | ||
1074 | if (m == 0 || !read_write(confd, packet, m + sizeof(u16), 0)) | |
feba5c1d SK |
1075 | return packet; |
1076 | } | |
1077 | } | |
1078 | ||
1697269c | 1079 | static struct frec *allocate_frec(time_t now) |
9e4abcb5 | 1080 | { |
1697269c SK |
1081 | struct frec *f; |
1082 | ||
5aabfc78 | 1083 | if ((f = (struct frec *)whine_malloc(sizeof(struct frec)))) |
9e4abcb5 | 1084 | { |
1a6bca81 | 1085 | f->next = daemon->frec_list; |
1697269c | 1086 | f->time = now; |
832af0ba | 1087 | f->sentto = NULL; |
1a6bca81 | 1088 | f->rfd4 = NULL; |
28866e95 | 1089 | f->flags = 0; |
1a6bca81 SK |
1090 | #ifdef HAVE_IPV6 |
1091 | f->rfd6 = NULL; | |
1092 | #endif | |
1093 | daemon->frec_list = f; | |
1697269c | 1094 | } |
9e4abcb5 | 1095 | |
1697269c SK |
1096 | return f; |
1097 | } | |
9e4abcb5 | 1098 | |
1a6bca81 SK |
1099 | static struct randfd *allocate_rfd(int family) |
1100 | { | |
1101 | static int finger = 0; | |
1102 | int i; | |
1103 | ||
1104 | /* limit the number of sockets we have open to avoid starvation of | |
1105 | (eg) TFTP. Once we have a reasonable number, randomness should be OK */ | |
1106 | ||
1107 | for (i = 0; i < RANDOM_SOCKS; i++) | |
9009d746 | 1108 | if (daemon->randomsocks[i].refcount == 0) |
1a6bca81 | 1109 | { |
9009d746 SK |
1110 | if ((daemon->randomsocks[i].fd = random_sock(family)) == -1) |
1111 | break; | |
1112 | ||
1a6bca81 SK |
1113 | daemon->randomsocks[i].refcount = 1; |
1114 | daemon->randomsocks[i].family = family; | |
1115 | return &daemon->randomsocks[i]; | |
1116 | } | |
1117 | ||
9009d746 | 1118 | /* No free ones or cannot get new socket, grab an existing one */ |
1a6bca81 SK |
1119 | for (i = 0; i < RANDOM_SOCKS; i++) |
1120 | { | |
1121 | int j = (i+finger) % RANDOM_SOCKS; | |
9009d746 SK |
1122 | if (daemon->randomsocks[j].refcount != 0 && |
1123 | daemon->randomsocks[j].family == family && | |
1124 | daemon->randomsocks[j].refcount != 0xffff) | |
1a6bca81 SK |
1125 | { |
1126 | finger = j; | |
1127 | daemon->randomsocks[j].refcount++; | |
1128 | return &daemon->randomsocks[j]; | |
1129 | } | |
1130 | } | |
1131 | ||
1132 | return NULL; /* doom */ | |
1133 | } | |
1134 | ||
1135 | static void free_frec(struct frec *f) | |
1136 | { | |
1137 | if (f->rfd4 && --(f->rfd4->refcount) == 0) | |
1138 | close(f->rfd4->fd); | |
1139 | ||
1140 | f->rfd4 = NULL; | |
1141 | f->sentto = NULL; | |
28866e95 | 1142 | f->flags = 0; |
1a6bca81 SK |
1143 | |
1144 | #ifdef HAVE_IPV6 | |
1145 | if (f->rfd6 && --(f->rfd6->refcount) == 0) | |
1146 | close(f->rfd6->fd); | |
1147 | ||
1148 | f->rfd6 = NULL; | |
1149 | #endif | |
1150 | } | |
1151 | ||
1697269c SK |
1152 | /* if wait==NULL return a free or older than TIMEOUT record. |
1153 | else return *wait zero if one available, or *wait is delay to | |
1a6bca81 SK |
1154 | when the oldest in-use record will expire. Impose an absolute |
1155 | limit of 4*TIMEOUT before we wipe things (for random sockets) */ | |
5aabfc78 | 1156 | struct frec *get_new_frec(time_t now, int *wait) |
1697269c | 1157 | { |
1a6bca81 | 1158 | struct frec *f, *oldest, *target; |
1697269c SK |
1159 | int count; |
1160 | ||
1161 | if (wait) | |
1162 | *wait = 0; | |
1163 | ||
1a6bca81 | 1164 | for (f = daemon->frec_list, oldest = NULL, target = NULL, count = 0; f; f = f->next, count++) |
832af0ba | 1165 | if (!f->sentto) |
1a6bca81 SK |
1166 | target = f; |
1167 | else | |
1697269c | 1168 | { |
1a6bca81 SK |
1169 | if (difftime(now, f->time) >= 4*TIMEOUT) |
1170 | { | |
1171 | free_frec(f); | |
1172 | target = f; | |
1173 | } | |
1174 | ||
1175 | if (!oldest || difftime(f->time, oldest->time) <= 0) | |
1176 | oldest = f; | |
1697269c | 1177 | } |
1a6bca81 SK |
1178 | |
1179 | if (target) | |
1180 | { | |
1181 | target->time = now; | |
1182 | return target; | |
1183 | } | |
9e4abcb5 SK |
1184 | |
1185 | /* can't find empty one, use oldest if there is one | |
1186 | and it's older than timeout */ | |
1697269c | 1187 | if (oldest && ((int)difftime(now, oldest->time)) >= TIMEOUT) |
9e4abcb5 | 1188 | { |
1697269c SK |
1189 | /* keep stuff for twice timeout if we can by allocating a new |
1190 | record instead */ | |
1191 | if (difftime(now, oldest->time) < 2*TIMEOUT && | |
1192 | count <= daemon->ftabsize && | |
1193 | (f = allocate_frec(now))) | |
1194 | return f; | |
1195 | ||
1196 | if (!wait) | |
1197 | { | |
1a6bca81 | 1198 | free_frec(oldest); |
1697269c SK |
1199 | oldest->time = now; |
1200 | } | |
9e4abcb5 SK |
1201 | return oldest; |
1202 | } | |
1203 | ||
1697269c | 1204 | /* none available, calculate time 'till oldest record expires */ |
208b65c5 | 1205 | if (count > daemon->ftabsize) |
1697269c SK |
1206 | { |
1207 | if (oldest && wait) | |
1208 | *wait = oldest->time + (time_t)TIMEOUT - now; | |
9e4abcb5 SK |
1209 | return NULL; |
1210 | } | |
1697269c SK |
1211 | |
1212 | if (!(f = allocate_frec(now)) && wait) | |
1213 | /* wait one second on malloc failure */ | |
1214 | *wait = 1; | |
9e4abcb5 | 1215 | |
9e4abcb5 SK |
1216 | return f; /* OK if malloc fails and this is NULL */ |
1217 | } | |
1218 | ||
832af0ba SK |
1219 | /* crc is all-ones if not known. */ |
1220 | static struct frec *lookup_frec(unsigned short id, unsigned int crc) | |
9e4abcb5 SK |
1221 | { |
1222 | struct frec *f; | |
1223 | ||
1a6bca81 | 1224 | for(f = daemon->frec_list; f; f = f->next) |
832af0ba SK |
1225 | if (f->sentto && f->new_id == id && |
1226 | (f->crc == crc || crc == 0xffffffff)) | |
9e4abcb5 SK |
1227 | return f; |
1228 | ||
1229 | return NULL; | |
1230 | } | |
1231 | ||
1232 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
1233 | union mysockaddr *addr, |
1234 | unsigned int crc) | |
9e4abcb5 | 1235 | { |
feba5c1d SK |
1236 | struct frec *f; |
1237 | ||
1a6bca81 | 1238 | for(f = daemon->frec_list; f; f = f->next) |
832af0ba | 1239 | if (f->sentto && |
9e4abcb5 | 1240 | f->orig_id == id && |
fd9fa481 | 1241 | f->crc == crc && |
9e4abcb5 SK |
1242 | sockaddr_isequal(&f->source, addr)) |
1243 | return f; | |
1244 | ||
1245 | return NULL; | |
1246 | } | |
1247 | ||
849a8357 | 1248 | /* A server record is going away, remove references to it */ |
5aabfc78 | 1249 | void server_gone(struct server *server) |
849a8357 SK |
1250 | { |
1251 | struct frec *f; | |
1252 | ||
1a6bca81 | 1253 | for (f = daemon->frec_list; f; f = f->next) |
832af0ba | 1254 | if (f->sentto && f->sentto == server) |
1a6bca81 | 1255 | free_frec(f); |
849a8357 SK |
1256 | |
1257 | if (daemon->last_server == server) | |
1258 | daemon->last_server = NULL; | |
1259 | ||
1260 | if (daemon->srv_save == server) | |
1261 | daemon->srv_save = NULL; | |
1262 | } | |
9e4abcb5 | 1263 | |
316e2730 SK |
1264 | /* return unique random ids. */ |
1265 | static unsigned short get_id(unsigned int crc) | |
9e4abcb5 SK |
1266 | { |
1267 | unsigned short ret = 0; | |
832af0ba | 1268 | |
316e2730 | 1269 | do |
832af0ba SK |
1270 | ret = rand16(); |
1271 | while (lookup_frec(ret, crc)); | |
1272 | ||
9e4abcb5 SK |
1273 | return ret; |
1274 | } | |
1275 | ||
1276 | ||
1277 | ||
1278 | ||
1279 |