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73a08a24 | 1 | /* dnsmasq is Copyright (c) 2000-2009 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); | |
832af0ba | 23 | static unsigned short get_id(int force, unsigned short force_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 */ |
cdeda28f | 29 | static void send_from(int fd, int nowild, char *packet, size_t len, |
dfa666f2 SK |
30 | union mysockaddr *to, struct all_addr *source, |
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) |
26128d27 SK |
68 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
69 | pkt->ipi_ifindex = 0; | |
70 | pkt->ipi_spec_dst = source->addr.addr4; | |
71 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
72 | cmptr->cmsg_level = SOL_IP; | |
73 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 74 | #elif defined(IP_SENDSRCADDR) |
26128d27 SK |
75 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
76 | *a = source->addr.addr4; | |
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 SK |
84 | { |
85 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
86 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
87 | pkt->ipi6_addr = source->addr.addr6; | |
88 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
89 | cmptr->cmsg_type = IPV6_PKTINFO; | |
90 | cmptr->cmsg_level = IPV6_LEVEL; | |
91 | } | |
3d8df260 SK |
92 | #else |
93 | iface = 0; /* eliminate warning */ | |
44a2a316 | 94 | #endif |
26128d27 | 95 | } |
feba5c1d | 96 | |
fd9fa481 SK |
97 | retry: |
98 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 99 | { |
fd9fa481 SK |
100 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
101 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
102 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
103 | if (errno == EINVAL && msg.msg_controllen) | |
104 | { | |
105 | msg.msg_controllen = 0; | |
106 | goto retry; | |
107 | } | |
108 | if (retry_send()) | |
109 | goto retry; | |
feba5c1d | 110 | } |
9e4abcb5 | 111 | } |
44a2a316 | 112 | |
5aabfc78 | 113 | static unsigned short search_servers(time_t now, struct all_addr **addrpp, |
36717eee | 114 | unsigned short qtype, char *qdomain, int *type, char **domain) |
feba5c1d SK |
115 | |
116 | { | |
117 | /* If the query ends in the domain in one of our servers, set | |
118 | domain to point to that name. We find the largest match to allow both | |
119 | domain.org and sub.domain.org to exist. */ | |
120 | ||
121 | unsigned int namelen = strlen(qdomain); | |
122 | unsigned int matchlen = 0; | |
123 | struct server *serv; | |
124 | unsigned short flags = 0; | |
125 | ||
3be34541 | 126 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 127 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 128 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d SK |
129 | { |
130 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
131 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 132 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
133 | flags = F_NXDOMAIN; |
134 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
135 | { | |
136 | if (sflag & qtype) | |
137 | { | |
138 | flags = sflag; | |
139 | if (serv->addr.sa.sa_family == AF_INET) | |
140 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 141 | #ifdef HAVE_IPV6 |
36717eee SK |
142 | else |
143 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 144 | #endif |
36717eee | 145 | } |
824af85b | 146 | else if (!flags || (flags & F_NXDOMAIN)) |
36717eee SK |
147 | flags = F_NOERR; |
148 | } | |
feba5c1d SK |
149 | } |
150 | else if (serv->flags & SERV_HAS_DOMAIN) | |
151 | { | |
152 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 153 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 154 | if (namelen >= domainlen && |
b8187c80 SK |
155 | hostname_isequal(matchstart, serv->domain) && |
156 | domainlen >= matchlen && | |
cdeda28f | 157 | (domainlen == 0 || namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) |
feba5c1d SK |
158 | { |
159 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
160 | *type = SERV_HAS_DOMAIN; | |
161 | *domain = serv->domain; | |
162 | matchlen = domainlen; | |
feba5c1d | 163 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
164 | flags = F_NXDOMAIN; |
165 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 166 | { |
824af85b | 167 | if (sflag & qtype) |
36717eee | 168 | { |
824af85b | 169 | flags = sflag; |
36717eee SK |
170 | if (serv->addr.sa.sa_family == AF_INET) |
171 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 172 | #ifdef HAVE_IPV6 |
36717eee SK |
173 | else |
174 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 175 | #endif |
36717eee | 176 | } |
824af85b | 177 | else if (!flags || (flags & F_NXDOMAIN)) |
36717eee | 178 | flags = F_NOERR; |
feba5c1d SK |
179 | } |
180 | } | |
181 | } | |
182 | ||
824af85b SK |
183 | if (flags == 0 && !(qtype & F_BIGNAME) && |
184 | (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) | |
185 | /* don't forward simple names, make exception for NS queries and empty name. */ | |
36717eee SK |
186 | flags = F_NXDOMAIN; |
187 | ||
5aabfc78 | 188 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now)) |
c1bb8504 | 189 | flags = F_NOERR; |
feba5c1d | 190 | |
824af85b SK |
191 | if (flags) |
192 | { | |
193 | int logflags = 0; | |
194 | ||
195 | if (flags == F_NXDOMAIN || flags == F_NOERR) | |
196 | logflags = F_NEG | qtype; | |
197 | ||
1a6bca81 | 198 | log_query(logflags | flags | F_CONFIG | F_FORWARD, qdomain, *addrpp, NULL); |
824af85b | 199 | } |
feba5c1d SK |
200 | |
201 | return flags; | |
202 | } | |
44a2a316 | 203 | |
824af85b SK |
204 | static int forward_query(int udpfd, union mysockaddr *udpaddr, |
205 | struct all_addr *dst_addr, unsigned int dst_iface, | |
206 | HEADER *header, size_t plen, time_t now, struct frec *forward) | |
9e4abcb5 | 207 | { |
9e4abcb5 | 208 | char *domain = NULL; |
0a852541 | 209 | int type = 0; |
9e4abcb5 | 210 | struct all_addr *addrp = NULL; |
cdeda28f | 211 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
9e4abcb5 | 212 | unsigned short flags = 0; |
cdeda28f | 213 | unsigned short gotname = extract_request(header, plen, daemon->namebuff, NULL); |
de37951c | 214 | struct server *start = NULL; |
3d8df260 SK |
215 | |
216 | /* may be no servers available. */ | |
217 | if (!daemon->servers) | |
9e4abcb5 | 218 | forward = NULL; |
b8187c80 | 219 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 220 | { |
de37951c | 221 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 222 | domain = forward->sentto->domain; |
824af85b | 223 | forward->sentto->failed_queries++; |
3be34541 | 224 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 225 | { |
0a852541 | 226 | forward->forwardall = 1; |
3be34541 | 227 | daemon->last_server = NULL; |
de37951c | 228 | } |
9e4abcb5 | 229 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 230 | if (!(start = forward->sentto->next)) |
3be34541 | 231 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
232 | header->id = htons(forward->new_id); |
233 | } | |
234 | else | |
235 | { | |
236 | if (gotname) | |
5aabfc78 | 237 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 238 | |
5aabfc78 | 239 | if (!flags && !(forward = get_new_frec(now, NULL))) |
feba5c1d SK |
240 | /* table full - server failure. */ |
241 | flags = F_NEG; | |
9e4abcb5 SK |
242 | |
243 | if (forward) | |
244 | { | |
832af0ba SK |
245 | /* force unchanging id for signed packets */ |
246 | int is_sign; | |
247 | find_pseudoheader(header, plen, NULL, NULL, &is_sign); | |
248 | ||
0a852541 SK |
249 | forward->source = *udpaddr; |
250 | forward->dest = *dst_addr; | |
251 | forward->iface = dst_iface; | |
0a852541 | 252 | forward->orig_id = ntohs(header->id); |
832af0ba SK |
253 | forward->new_id = get_id(is_sign, forward->orig_id, crc); |
254 | forward->fd = udpfd; | |
0a852541 SK |
255 | forward->crc = crc; |
256 | forward->forwardall = 0; | |
257 | header->id = htons(forward->new_id); | |
258 | ||
9e4abcb5 SK |
259 | /* In strict_order mode, or when using domain specific servers |
260 | always try servers in the order specified in resolv.conf, | |
261 | otherwise, use the one last known to work. */ | |
262 | ||
3be34541 SK |
263 | if (type != 0 || (daemon->options & OPT_ORDER)) |
264 | start = daemon->servers; | |
1f15b81d SK |
265 | else if (!(start = daemon->last_server) || |
266 | daemon->forwardcount++ > FORWARD_TEST || | |
267 | difftime(now, daemon->forwardtime) > FORWARD_TIME) | |
de37951c | 268 | { |
3be34541 | 269 | start = daemon->servers; |
0a852541 | 270 | forward->forwardall = 1; |
1f15b81d SK |
271 | daemon->forwardcount = 0; |
272 | daemon->forwardtime = now; | |
de37951c | 273 | } |
9e4abcb5 SK |
274 | } |
275 | } | |
feba5c1d | 276 | |
9e4abcb5 SK |
277 | /* check for send errors here (no route to host) |
278 | if we fail to send to all nameservers, send back an error | |
279 | packet straight away (helps modem users when offline) */ | |
280 | ||
281 | if (!flags && forward) | |
282 | { | |
de37951c SK |
283 | struct server *firstsentto = start; |
284 | int forwarded = 0; | |
285 | ||
9e4abcb5 SK |
286 | while (1) |
287 | { | |
9e4abcb5 SK |
288 | /* only send to servers dealing with our domain. |
289 | domain may be NULL, in which case server->domain | |
290 | must be NULL also. */ | |
291 | ||
de37951c | 292 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
293 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
294 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 295 | { |
1a6bca81 SK |
296 | int fd; |
297 | ||
298 | /* find server socket to use, may need to get random one. */ | |
299 | if (start->sfd) | |
300 | fd = start->sfd->fd; | |
301 | else | |
302 | { | |
303 | #ifdef HAVE_IPV6 | |
304 | if (start->addr.sa.sa_family == AF_INET6) | |
305 | { | |
306 | if (!forward->rfd6 && | |
307 | !(forward->rfd6 = allocate_rfd(AF_INET6))) | |
308 | break; | |
3927da46 | 309 | daemon->rfd_save = forward->rfd6; |
1a6bca81 SK |
310 | fd = forward->rfd6->fd; |
311 | } | |
312 | else | |
313 | #endif | |
314 | { | |
315 | if (!forward->rfd4 && | |
316 | !(forward->rfd4 = allocate_rfd(AF_INET))) | |
317 | break; | |
3927da46 | 318 | daemon->rfd_save = forward->rfd4; |
1a6bca81 SK |
319 | fd = forward->rfd4->fd; |
320 | } | |
321 | } | |
322 | ||
323 | if (sendto(fd, (char *)header, plen, 0, | |
feba5c1d | 324 | &start->addr.sa, |
fd9fa481 SK |
325 | sa_len(&start->addr)) == -1) |
326 | { | |
327 | if (retry_send()) | |
328 | continue; | |
329 | } | |
330 | else | |
9e4abcb5 | 331 | { |
cdeda28f SK |
332 | /* Keep info in case we want to re-send this packet */ |
333 | daemon->srv_save = start; | |
334 | daemon->packet_len = plen; | |
335 | ||
de37951c | 336 | if (!gotname) |
3be34541 | 337 | strcpy(daemon->namebuff, "query"); |
de37951c | 338 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 339 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 340 | (struct all_addr *)&start->addr.in.sin_addr, NULL); |
de37951c SK |
341 | #ifdef HAVE_IPV6 |
342 | else | |
3be34541 | 343 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 344 | (struct all_addr *)&start->addr.in6.sin6_addr, NULL); |
de37951c | 345 | #endif |
824af85b | 346 | start->queries++; |
de37951c SK |
347 | forwarded = 1; |
348 | forward->sentto = start; | |
0a852541 | 349 | if (!forward->forwardall) |
de37951c | 350 | break; |
0a852541 | 351 | forward->forwardall++; |
9e4abcb5 SK |
352 | } |
353 | } | |
354 | ||
de37951c | 355 | if (!(start = start->next)) |
3be34541 | 356 | start = daemon->servers; |
9e4abcb5 | 357 | |
de37951c | 358 | if (start == firstsentto) |
9e4abcb5 SK |
359 | break; |
360 | } | |
361 | ||
de37951c | 362 | if (forwarded) |
824af85b | 363 | return 1; |
de37951c | 364 | |
9e4abcb5 SK |
365 | /* could not send on, prepare to return */ |
366 | header->id = htons(forward->orig_id); | |
1a6bca81 | 367 | free_frec(forward); /* cancel */ |
9e4abcb5 SK |
368 | } |
369 | ||
370 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
371 | if (udpfd != -1) |
372 | { | |
cdeda28f | 373 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
b8187c80 SK |
374 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); |
375 | } | |
376 | ||
824af85b | 377 | return 0; |
9e4abcb5 SK |
378 | } |
379 | ||
5aabfc78 | 380 | static size_t process_reply(HEADER *header, time_t now, |
832af0ba | 381 | struct server *server, size_t n) |
feba5c1d | 382 | { |
36717eee | 383 | unsigned char *pheader, *sizep; |
832af0ba | 384 | int munged = 0, is_sign; |
cdeda28f SK |
385 | size_t plen; |
386 | ||
feba5c1d | 387 | /* If upstream is advertising a larger UDP packet size |
9009d746 SK |
388 | than we allow, trim it so that we don't get overlarge |
389 | requests for the client. We can't do this for signed packets. */ | |
feba5c1d | 390 | |
832af0ba | 391 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign)) && !is_sign) |
feba5c1d SK |
392 | { |
393 | unsigned short udpsz; | |
36717eee | 394 | unsigned char *psave = sizep; |
feba5c1d | 395 | |
36717eee | 396 | GETSHORT(udpsz, sizep); |
3be34541 SK |
397 | if (udpsz > daemon->edns_pktsz) |
398 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
399 | } |
400 | ||
1b7ecd11 | 401 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
0a852541 SK |
402 | return n; |
403 | ||
feba5c1d | 404 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
405 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
406 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 407 | { |
3d8df260 | 408 | prettyprint_addr(&server->addr, daemon->namebuff); |
f2621c7f | 409 | my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
0a852541 SK |
410 | if (!(daemon->options & OPT_LOG)) |
411 | server->flags |= SERV_WARNED_RECURSIVE; | |
412 | } | |
413 | ||
fd9fa481 SK |
414 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
415 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 416 | { |
fd9fa481 SK |
417 | munged = 1; |
418 | header->rcode = NXDOMAIN; | |
419 | header->aa = 0; | |
36717eee | 420 | } |
fd9fa481 | 421 | else |
36717eee | 422 | { |
fd9fa481 SK |
423 | if (header->rcode == NXDOMAIN && |
424 | extract_request(header, n, daemon->namebuff, NULL) && | |
5aabfc78 | 425 | check_for_local_domain(daemon->namebuff, now)) |
36717eee SK |
426 | { |
427 | /* if we forwarded a query for a locally known name (because it was for | |
428 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
429 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
430 | munged = 1; |
431 | header->aa = 1; | |
432 | header->rcode = NOERROR; | |
feba5c1d | 433 | } |
832af0ba | 434 | |
824af85b SK |
435 | if (extract_addresses(header, n, daemon->namebuff, now)) |
436 | { | |
437 | my_syslog(LOG_WARNING, _("possible DNS-rebind attack detected")); | |
438 | munged = 1; | |
439 | } | |
feba5c1d | 440 | } |
fd9fa481 SK |
441 | |
442 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
443 | nameserver info. */ | |
444 | ||
445 | if (munged) | |
446 | { | |
447 | header->ancount = htons(0); | |
448 | header->nscount = htons(0); | |
449 | header->arcount = htons(0); | |
450 | } | |
451 | ||
36717eee SK |
452 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
453 | sections of the packet. Find the new length here and put back pseudoheader | |
454 | if it was removed. */ | |
455 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
456 | } |
457 | ||
3be34541 | 458 | /* sets new last_server */ |
1a6bca81 | 459 | void reply_query(int fd, int family, time_t now) |
9e4abcb5 SK |
460 | { |
461 | /* packet from peer server, extract data for cache, and send to | |
462 | original requester */ | |
9e4abcb5 | 463 | HEADER *header; |
de37951c | 464 | union mysockaddr serveraddr; |
832af0ba | 465 | struct frec *forward; |
de37951c | 466 | socklen_t addrlen = sizeof(serveraddr); |
1a6bca81 | 467 | ssize_t n = recvfrom(fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
cdeda28f | 468 | size_t nn; |
1a6bca81 SK |
469 | struct server *server; |
470 | ||
cdeda28f SK |
471 | /* packet buffer overwritten */ |
472 | daemon->srv_save = NULL; | |
832af0ba | 473 | |
de37951c | 474 | /* Determine the address of the server replying so that we can mark that as good */ |
1a6bca81 | 475 | serveraddr.sa.sa_family = family; |
de37951c SK |
476 | #ifdef HAVE_IPV6 |
477 | if (serveraddr.sa.sa_family == AF_INET6) | |
5e9e0efb | 478 | serveraddr.in6.sin6_flowinfo = 0; |
de37951c | 479 | #endif |
9e4abcb5 | 480 | |
1a6bca81 SK |
481 | /* spoof check: answer must come from known server, */ |
482 | for (server = daemon->servers; server; server = server->next) | |
483 | if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR)) && | |
484 | sockaddr_isequal(&server->addr, &serveraddr)) | |
485 | break; | |
486 | ||
3be34541 | 487 | header = (HEADER *)daemon->packet; |
fd9fa481 | 488 | |
1a6bca81 SK |
489 | if (!server || |
490 | n < (int)sizeof(HEADER) || !header->qr || | |
491 | !(forward = lookup_frec(ntohs(header->id), questions_crc(header, n, daemon->namebuff)))) | |
492 | return; | |
493 | ||
494 | server = forward->sentto; | |
495 | ||
496 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && | |
497 | !(daemon->options & OPT_ORDER) && | |
498 | forward->forwardall == 0) | |
499 | /* for broken servers, attempt to send to another one. */ | |
9e4abcb5 | 500 | { |
1a6bca81 SK |
501 | unsigned char *pheader; |
502 | size_t plen; | |
503 | int is_sign; | |
832af0ba | 504 | |
1a6bca81 SK |
505 | /* recreate query from reply */ |
506 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign); | |
507 | if (!is_sign) | |
832af0ba | 508 | { |
1a6bca81 SK |
509 | header->ancount = htons(0); |
510 | header->nscount = htons(0); | |
511 | header->arcount = htons(0); | |
512 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) | |
832af0ba | 513 | { |
1a6bca81 SK |
514 | header->qr = 0; |
515 | header->tc = 0; | |
516 | forward_query(-1, NULL, NULL, 0, header, nn, now, forward); | |
517 | return; | |
832af0ba | 518 | } |
832af0ba | 519 | } |
1a6bca81 SK |
520 | } |
521 | ||
522 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
523 | { | |
524 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
525 | server = NULL; | |
526 | else | |
b8187c80 | 527 | { |
1a6bca81 SK |
528 | struct server *last_server; |
529 | ||
530 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
531 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
532 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
533 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
534 | { | |
535 | server = last_server; | |
536 | break; | |
537 | } | |
538 | } | |
539 | if (!(daemon->options & OPT_ALL_SERVERS)) | |
540 | daemon->last_server = server; | |
541 | } | |
542 | ||
543 | /* If the answer is an error, keep the forward record in place in case | |
544 | we get a good reply from another server. Kill it when we've | |
545 | had replies from all to avoid filling the forwarding table when | |
546 | everything is broken */ | |
547 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
548 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
549 | { | |
550 | if ((nn = process_reply(header, now, server, (size_t)n))) | |
551 | { | |
552 | header->id = htons(forward->orig_id); | |
553 | header->ra = 1; /* recursion if available */ | |
554 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn, | |
555 | &forward->source, &forward->dest, forward->iface); | |
b8187c80 | 556 | } |
1a6bca81 | 557 | free_frec(forward); /* cancel */ |
9e4abcb5 | 558 | } |
9e4abcb5 | 559 | } |
44a2a316 | 560 | |
1a6bca81 | 561 | |
5aabfc78 | 562 | void receive_query(struct listener *listen, time_t now) |
44a2a316 | 563 | { |
3be34541 | 564 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 565 | union mysockaddr source_addr; |
c1bb8504 | 566 | unsigned short type; |
44a2a316 | 567 | struct all_addr dst_addr; |
f6b7dc47 | 568 | struct in_addr netmask, dst_addr_4; |
cdeda28f SK |
569 | size_t m; |
570 | ssize_t n; | |
571 | int if_index = 0; | |
44a2a316 SK |
572 | struct iovec iov[1]; |
573 | struct msghdr msg; | |
574 | struct cmsghdr *cmptr; | |
44a2a316 SK |
575 | union { |
576 | struct cmsghdr align; /* this ensures alignment */ | |
577 | #ifdef HAVE_IPV6 | |
578 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
579 | #endif | |
5e9e0efb | 580 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 | 581 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
824af85b SK |
582 | #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK) |
583 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
584 | CMSG_SPACE(sizeof(unsigned int))]; | |
44a2a316 SK |
585 | #elif defined(IP_RECVDSTADDR) |
586 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
587 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
588 | #endif | |
589 | } control_u; | |
590 | ||
cdeda28f SK |
591 | /* packet buffer overwritten */ |
592 | daemon->srv_save = NULL; | |
593 | ||
f6b7dc47 SK |
594 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
595 | { | |
596 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
597 | netmask = listen->iface->netmask; | |
598 | } | |
599 | else | |
3d8df260 SK |
600 | { |
601 | dst_addr_4.s_addr = 0; | |
602 | netmask.s_addr = 0; | |
603 | } | |
f6b7dc47 | 604 | |
3be34541 SK |
605 | iov[0].iov_base = daemon->packet; |
606 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
607 | |
608 | msg.msg_control = control_u.control; | |
609 | msg.msg_controllen = sizeof(control_u); | |
610 | msg.msg_flags = 0; | |
611 | msg.msg_name = &source_addr; | |
612 | msg.msg_namelen = sizeof(source_addr); | |
613 | msg.msg_iov = iov; | |
614 | msg.msg_iovlen = 1; | |
615 | ||
de37951c | 616 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 617 | return; |
44a2a316 | 618 | |
5e9e0efb SK |
619 | if (n < (int)sizeof(HEADER) || |
620 | (msg.msg_flags & MSG_TRUNC) || | |
621 | header->qr) | |
26128d27 SK |
622 | return; |
623 | ||
44a2a316 SK |
624 | source_addr.sa.sa_family = listen->family; |
625 | #ifdef HAVE_IPV6 | |
626 | if (listen->family == AF_INET6) | |
5e9e0efb | 627 | source_addr.in6.sin6_flowinfo = 0; |
44a2a316 SK |
628 | #endif |
629 | ||
26128d27 SK |
630 | if (!(daemon->options & OPT_NOWILD)) |
631 | { | |
632 | struct ifreq ifr; | |
633 | ||
634 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
635 | return; | |
44a2a316 | 636 | |
5e9e0efb | 637 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
638 | if (listen->family == AF_INET) |
639 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
640 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
641 | { | |
f6b7dc47 | 642 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
643 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
644 | } | |
645 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
646 | if (listen->family == AF_INET) | |
44a2a316 | 647 | { |
26128d27 SK |
648 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
649 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 650 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 | 651 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
824af85b SK |
652 | #ifdef HAVE_SOLARIS_NETWORK |
653 | if_index = *((unsigned int *)CMSG_DATA(cmptr)); | |
654 | #else | |
26128d27 | 655 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; |
824af85b | 656 | #endif |
44a2a316 | 657 | } |
44a2a316 | 658 | #endif |
26128d27 | 659 | |
44a2a316 | 660 | #ifdef HAVE_IPV6 |
26128d27 SK |
661 | if (listen->family == AF_INET6) |
662 | { | |
663 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
664 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
665 | { | |
666 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
667 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
668 | } | |
669 | } | |
44a2a316 | 670 | #endif |
26128d27 SK |
671 | |
672 | /* enforce available interface configuration */ | |
673 | ||
7622fc06 SK |
674 | if (!indextoname(listen->fd, if_index, ifr.ifr_name) || |
675 | !iface_check(listen->family, &dst_addr, ifr.ifr_name, &if_index)) | |
5e9e0efb | 676 | return; |
832af0ba SK |
677 | |
678 | if (listen->family == AF_INET && | |
679 | (daemon->options & OPT_LOCALISE) && | |
680 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
681 | return; | |
682 | ||
683 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
44a2a316 SK |
684 | } |
685 | ||
cdeda28f | 686 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
44a2a316 | 687 | { |
1a6bca81 SK |
688 | char types[20]; |
689 | ||
690 | querystr(types, type); | |
691 | ||
44a2a316 | 692 | if (listen->family == AF_INET) |
3be34541 | 693 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 694 | (struct all_addr *)&source_addr.in.sin_addr, types); |
44a2a316 SK |
695 | #ifdef HAVE_IPV6 |
696 | else | |
3be34541 | 697 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 698 | (struct all_addr *)&source_addr.in6.sin6_addr, types); |
44a2a316 SK |
699 | #endif |
700 | } | |
701 | ||
5aabfc78 | 702 | m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n, |
f6b7dc47 | 703 | dst_addr_4, netmask, now); |
44a2a316 | 704 | if (m >= 1) |
824af85b SK |
705 | { |
706 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, | |
707 | m, &source_addr, &dst_addr, if_index); | |
708 | daemon->local_answer++; | |
709 | } | |
710 | else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index, | |
711 | header, (size_t)n, now, NULL)) | |
712 | daemon->queries_forwarded++; | |
44a2a316 | 713 | else |
824af85b | 714 | daemon->local_answer++; |
44a2a316 SK |
715 | } |
716 | ||
feba5c1d SK |
717 | /* The daemon forks before calling this: it should deal with one connection, |
718 | blocking as neccessary, and then return. Note, need to be a bit careful | |
719 | about resources for debug mode, when the fork is suppressed: that's | |
720 | done by the caller. */ | |
5aabfc78 | 721 | unsigned char *tcp_request(int confd, time_t now, |
3d8df260 | 722 | struct in_addr local_addr, struct in_addr netmask) |
feba5c1d | 723 | { |
cdeda28f SK |
724 | int size = 0; |
725 | size_t m; | |
c1bb8504 | 726 | unsigned short qtype, gotname; |
feba5c1d SK |
727 | unsigned char c1, c2; |
728 | /* Max TCP packet + slop */ | |
5aabfc78 | 729 | unsigned char *packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 730 | HEADER *header; |
3be34541 SK |
731 | struct server *last_server; |
732 | ||
feba5c1d SK |
733 | while (1) |
734 | { | |
735 | if (!packet || | |
736 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
737 | !(size = c1 << 8 | c2) || | |
738 | !read_write(confd, packet, size, 1)) | |
739 | return packet; | |
740 | ||
741 | if (size < (int)sizeof(HEADER)) | |
742 | continue; | |
743 | ||
744 | header = (HEADER *)packet; | |
745 | ||
3be34541 | 746 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
747 | { |
748 | union mysockaddr peer_addr; | |
749 | socklen_t peer_len = sizeof(union mysockaddr); | |
750 | ||
751 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
752 | { | |
1a6bca81 SK |
753 | char types[20]; |
754 | ||
755 | querystr(types, qtype); | |
756 | ||
feba5c1d | 757 | if (peer_addr.sa.sa_family == AF_INET) |
3be34541 | 758 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 759 | (struct all_addr *)&peer_addr.in.sin_addr, types); |
feba5c1d SK |
760 | #ifdef HAVE_IPV6 |
761 | else | |
3be34541 | 762 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 763 | (struct all_addr *)&peer_addr.in6.sin6_addr, types); |
feba5c1d SK |
764 | #endif |
765 | } | |
766 | } | |
767 | ||
768 | /* m > 0 if answered from cache */ | |
5aabfc78 | 769 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, |
f6b7dc47 | 770 | local_addr, netmask, now); |
5aabfc78 SK |
771 | |
772 | /* Do this by steam now we're not in the select() loop */ | |
773 | check_log_writer(NULL); | |
feba5c1d SK |
774 | |
775 | if (m == 0) | |
776 | { | |
777 | unsigned short flags = 0; | |
feba5c1d SK |
778 | struct all_addr *addrp = NULL; |
779 | int type = 0; | |
780 | char *domain = NULL; | |
781 | ||
782 | if (gotname) | |
5aabfc78 | 783 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 784 | |
3be34541 SK |
785 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
786 | last_server = daemon->servers; | |
787 | else | |
788 | last_server = daemon->last_server; | |
feba5c1d SK |
789 | |
790 | if (!flags && last_server) | |
791 | { | |
792 | struct server *firstsendto = NULL; | |
0a852541 SK |
793 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
794 | ||
feba5c1d SK |
795 | /* Loop round available servers until we succeed in connecting to one. |
796 | Note that this code subtley ensures that consecutive queries on this connection | |
797 | which can go to the same server, do so. */ | |
798 | while (1) | |
799 | { | |
800 | if (!firstsendto) | |
801 | firstsendto = last_server; | |
802 | else | |
803 | { | |
804 | if (!(last_server = last_server->next)) | |
3be34541 | 805 | last_server = daemon->servers; |
feba5c1d SK |
806 | |
807 | if (last_server == firstsendto) | |
808 | break; | |
809 | } | |
810 | ||
811 | /* server for wrong domain */ | |
812 | if (type != (last_server->flags & SERV_TYPE) || | |
813 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
814 | continue; | |
815 | ||
816 | if ((last_server->tcpfd == -1) && | |
817 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
824af85b SK |
818 | (!local_bind(last_server->tcpfd, &last_server->source_addr, last_server->interface, 1) || |
819 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1)) | |
feba5c1d SK |
820 | { |
821 | close(last_server->tcpfd); | |
822 | last_server->tcpfd = -1; | |
823 | } | |
824 | ||
825 | if (last_server->tcpfd == -1) | |
826 | continue; | |
824af85b | 827 | |
feba5c1d SK |
828 | c1 = size >> 8; |
829 | c2 = size; | |
830 | ||
831 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
832 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
833 | !read_write(last_server->tcpfd, packet, size, 0) || | |
834 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
835 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
836 | { | |
837 | close(last_server->tcpfd); | |
838 | last_server->tcpfd = -1; | |
839 | continue; | |
840 | } | |
824af85b | 841 | |
feba5c1d SK |
842 | m = (c1 << 8) | c2; |
843 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
844 | return packet; | |
845 | ||
846 | if (!gotname) | |
3be34541 | 847 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 848 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 849 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 850 | (struct all_addr *)&last_server->addr.in.sin_addr, NULL); |
feba5c1d SK |
851 | #ifdef HAVE_IPV6 |
852 | else | |
3be34541 | 853 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
1a6bca81 | 854 | (struct all_addr *)&last_server->addr.in6.sin6_addr, NULL); |
feba5c1d SK |
855 | #endif |
856 | ||
857 | /* There's no point in updating the cache, since this process will exit and | |
832af0ba | 858 | lose the information after a few queries. We make this call for the alias and |
feba5c1d | 859 | bogus-nxdomain side-effects. */ |
832af0ba SK |
860 | /* If the crc of the question section doesn't match the crc we sent, then |
861 | someone might be attempting to insert bogus values into the cache by | |
862 | sending replies containing questions and bogus answers. */ | |
863 | if (crc == questions_crc(header, (unsigned int)m, daemon->namebuff)) | |
5aabfc78 | 864 | m = process_reply(header, now, last_server, (unsigned int)m); |
feba5c1d SK |
865 | |
866 | break; | |
867 | } | |
868 | } | |
869 | ||
870 | /* In case of local answer or no connections made. */ | |
871 | if (m == 0) | |
3be34541 | 872 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d | 873 | } |
5aabfc78 SK |
874 | |
875 | check_log_writer(NULL); | |
feba5c1d SK |
876 | |
877 | c1 = m>>8; | |
878 | c2 = m; | |
879 | if (!read_write(confd, &c1, 1, 0) || | |
880 | !read_write(confd, &c2, 1, 0) || | |
881 | !read_write(confd, packet, m, 0)) | |
882 | return packet; | |
883 | } | |
884 | } | |
885 | ||
1697269c | 886 | static struct frec *allocate_frec(time_t now) |
9e4abcb5 | 887 | { |
1697269c SK |
888 | struct frec *f; |
889 | ||
5aabfc78 | 890 | if ((f = (struct frec *)whine_malloc(sizeof(struct frec)))) |
9e4abcb5 | 891 | { |
1a6bca81 | 892 | f->next = daemon->frec_list; |
1697269c | 893 | f->time = now; |
832af0ba | 894 | f->sentto = NULL; |
1a6bca81 SK |
895 | f->rfd4 = NULL; |
896 | #ifdef HAVE_IPV6 | |
897 | f->rfd6 = NULL; | |
898 | #endif | |
899 | daemon->frec_list = f; | |
1697269c | 900 | } |
9e4abcb5 | 901 | |
1697269c SK |
902 | return f; |
903 | } | |
9e4abcb5 | 904 | |
1a6bca81 SK |
905 | static struct randfd *allocate_rfd(int family) |
906 | { | |
907 | static int finger = 0; | |
908 | int i; | |
909 | ||
910 | /* limit the number of sockets we have open to avoid starvation of | |
911 | (eg) TFTP. Once we have a reasonable number, randomness should be OK */ | |
912 | ||
913 | for (i = 0; i < RANDOM_SOCKS; i++) | |
9009d746 | 914 | if (daemon->randomsocks[i].refcount == 0) |
1a6bca81 | 915 | { |
9009d746 SK |
916 | if ((daemon->randomsocks[i].fd = random_sock(family)) == -1) |
917 | break; | |
918 | ||
1a6bca81 SK |
919 | daemon->randomsocks[i].refcount = 1; |
920 | daemon->randomsocks[i].family = family; | |
921 | return &daemon->randomsocks[i]; | |
922 | } | |
923 | ||
9009d746 | 924 | /* No free ones or cannot get new socket, grab an existing one */ |
1a6bca81 SK |
925 | for (i = 0; i < RANDOM_SOCKS; i++) |
926 | { | |
927 | int j = (i+finger) % RANDOM_SOCKS; | |
9009d746 SK |
928 | if (daemon->randomsocks[j].refcount != 0 && |
929 | daemon->randomsocks[j].family == family && | |
930 | daemon->randomsocks[j].refcount != 0xffff) | |
1a6bca81 SK |
931 | { |
932 | finger = j; | |
933 | daemon->randomsocks[j].refcount++; | |
934 | return &daemon->randomsocks[j]; | |
935 | } | |
936 | } | |
937 | ||
938 | return NULL; /* doom */ | |
939 | } | |
940 | ||
941 | static void free_frec(struct frec *f) | |
942 | { | |
943 | if (f->rfd4 && --(f->rfd4->refcount) == 0) | |
944 | close(f->rfd4->fd); | |
945 | ||
946 | f->rfd4 = NULL; | |
947 | f->sentto = NULL; | |
948 | ||
949 | #ifdef HAVE_IPV6 | |
950 | if (f->rfd6 && --(f->rfd6->refcount) == 0) | |
951 | close(f->rfd6->fd); | |
952 | ||
953 | f->rfd6 = NULL; | |
954 | #endif | |
955 | } | |
956 | ||
1697269c SK |
957 | /* if wait==NULL return a free or older than TIMEOUT record. |
958 | else return *wait zero if one available, or *wait is delay to | |
1a6bca81 SK |
959 | when the oldest in-use record will expire. Impose an absolute |
960 | limit of 4*TIMEOUT before we wipe things (for random sockets) */ | |
5aabfc78 | 961 | struct frec *get_new_frec(time_t now, int *wait) |
1697269c | 962 | { |
1a6bca81 | 963 | struct frec *f, *oldest, *target; |
1697269c SK |
964 | int count; |
965 | ||
966 | if (wait) | |
967 | *wait = 0; | |
968 | ||
1a6bca81 | 969 | for (f = daemon->frec_list, oldest = NULL, target = NULL, count = 0; f; f = f->next, count++) |
832af0ba | 970 | if (!f->sentto) |
1a6bca81 SK |
971 | target = f; |
972 | else | |
1697269c | 973 | { |
1a6bca81 SK |
974 | if (difftime(now, f->time) >= 4*TIMEOUT) |
975 | { | |
976 | free_frec(f); | |
977 | target = f; | |
978 | } | |
979 | ||
980 | if (!oldest || difftime(f->time, oldest->time) <= 0) | |
981 | oldest = f; | |
1697269c | 982 | } |
1a6bca81 SK |
983 | |
984 | if (target) | |
985 | { | |
986 | target->time = now; | |
987 | return target; | |
988 | } | |
9e4abcb5 SK |
989 | |
990 | /* can't find empty one, use oldest if there is one | |
991 | and it's older than timeout */ | |
1697269c | 992 | if (oldest && ((int)difftime(now, oldest->time)) >= TIMEOUT) |
9e4abcb5 | 993 | { |
1697269c SK |
994 | /* keep stuff for twice timeout if we can by allocating a new |
995 | record instead */ | |
996 | if (difftime(now, oldest->time) < 2*TIMEOUT && | |
997 | count <= daemon->ftabsize && | |
998 | (f = allocate_frec(now))) | |
999 | return f; | |
1000 | ||
1001 | if (!wait) | |
1002 | { | |
1a6bca81 | 1003 | free_frec(oldest); |
1697269c SK |
1004 | oldest->time = now; |
1005 | } | |
9e4abcb5 SK |
1006 | return oldest; |
1007 | } | |
1008 | ||
1697269c | 1009 | /* none available, calculate time 'till oldest record expires */ |
208b65c5 | 1010 | if (count > daemon->ftabsize) |
1697269c SK |
1011 | { |
1012 | if (oldest && wait) | |
1013 | *wait = oldest->time + (time_t)TIMEOUT - now; | |
9e4abcb5 SK |
1014 | return NULL; |
1015 | } | |
1697269c SK |
1016 | |
1017 | if (!(f = allocate_frec(now)) && wait) | |
1018 | /* wait one second on malloc failure */ | |
1019 | *wait = 1; | |
9e4abcb5 | 1020 | |
9e4abcb5 SK |
1021 | return f; /* OK if malloc fails and this is NULL */ |
1022 | } | |
1023 | ||
832af0ba SK |
1024 | /* crc is all-ones if not known. */ |
1025 | static struct frec *lookup_frec(unsigned short id, unsigned int crc) | |
9e4abcb5 SK |
1026 | { |
1027 | struct frec *f; | |
1028 | ||
1a6bca81 | 1029 | for(f = daemon->frec_list; f; f = f->next) |
832af0ba SK |
1030 | if (f->sentto && f->new_id == id && |
1031 | (f->crc == crc || crc == 0xffffffff)) | |
9e4abcb5 SK |
1032 | return f; |
1033 | ||
1034 | return NULL; | |
1035 | } | |
1036 | ||
1037 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
1038 | union mysockaddr *addr, |
1039 | unsigned int crc) | |
9e4abcb5 | 1040 | { |
feba5c1d SK |
1041 | struct frec *f; |
1042 | ||
1a6bca81 | 1043 | for(f = daemon->frec_list; f; f = f->next) |
832af0ba | 1044 | if (f->sentto && |
9e4abcb5 | 1045 | f->orig_id == id && |
fd9fa481 | 1046 | f->crc == crc && |
9e4abcb5 SK |
1047 | sockaddr_isequal(&f->source, addr)) |
1048 | return f; | |
1049 | ||
1050 | return NULL; | |
1051 | } | |
1052 | ||
849a8357 | 1053 | /* A server record is going away, remove references to it */ |
5aabfc78 | 1054 | void server_gone(struct server *server) |
849a8357 SK |
1055 | { |
1056 | struct frec *f; | |
1057 | ||
1a6bca81 | 1058 | for (f = daemon->frec_list; f; f = f->next) |
832af0ba | 1059 | if (f->sentto && f->sentto == server) |
1a6bca81 | 1060 | free_frec(f); |
849a8357 SK |
1061 | |
1062 | if (daemon->last_server == server) | |
1063 | daemon->last_server = NULL; | |
1064 | ||
1065 | if (daemon->srv_save == server) | |
1066 | daemon->srv_save = NULL; | |
1067 | } | |
9e4abcb5 | 1068 | |
832af0ba SK |
1069 | /* return unique random ids. |
1070 | For signed packets we can't change the ID without breaking the | |
1071 | signing, so we keep the same one. In this case force is set, and this | |
1072 | routine degenerates into killing any conflicting forward record. */ | |
1073 | static unsigned short get_id(int force, unsigned short force_id, unsigned int crc) | |
9e4abcb5 SK |
1074 | { |
1075 | unsigned short ret = 0; | |
832af0ba SK |
1076 | |
1077 | if (force) | |
9e4abcb5 | 1078 | { |
832af0ba SK |
1079 | struct frec *f = lookup_frec(force_id, crc); |
1080 | if (f) | |
1a6bca81 | 1081 | free_frec(f); /* free */ |
832af0ba | 1082 | ret = force_id; |
9e4abcb5 | 1083 | } |
832af0ba SK |
1084 | else do |
1085 | ret = rand16(); | |
1086 | while (lookup_frec(ret, crc)); | |
1087 | ||
9e4abcb5 SK |
1088 | return ret; |
1089 | } | |
1090 | ||
1091 | ||
1092 | ||
1093 | ||
1094 |