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f6b7dc47 | 1 | /* dnsmasq is Copyright (c) 2000 - 2005 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 | |
5 | the Free Software Foundation; version 2 dated June, 1991. | |
6 | ||
7 | This program is distributed in the hope that it will be useful, | |
8 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | GNU General Public License for more details. | |
11 | */ | |
12 | ||
13 | /* Author's email: simon@thekelleys.org.uk */ | |
14 | ||
15 | #include "dnsmasq.h" | |
16 | ||
17 | static struct frec *frec_list; | |
18 | ||
19 | static struct frec *get_new_frec(time_t now); | |
20 | static struct frec *lookup_frec(unsigned short id); | |
21 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
22 | union mysockaddr *addr, |
23 | unsigned int crc); | |
9e4abcb5 SK |
24 | static unsigned short get_id(void); |
25 | ||
26 | /* May be called more than once. */ | |
27 | void forward_init(int first) | |
28 | { | |
29 | struct frec *f; | |
feba5c1d | 30 | |
9e4abcb5 SK |
31 | if (first) |
32 | frec_list = NULL; | |
33 | for (f = frec_list; f; f = f->next) | |
34 | f->new_id = 0; | |
35 | } | |
36 | ||
44a2a316 SK |
37 | /* Send a UDP packet with it's source address set as "source" |
38 | unless nowild is true, when we just send it with the kernel default */ | |
cdeda28f | 39 | static void send_from(int fd, int nowild, char *packet, size_t len, |
dfa666f2 SK |
40 | union mysockaddr *to, struct all_addr *source, |
41 | unsigned int iface) | |
9e4abcb5 | 42 | { |
44a2a316 SK |
43 | struct msghdr msg; |
44 | struct iovec iov[1]; | |
44a2a316 SK |
45 | union { |
46 | struct cmsghdr align; /* this ensures alignment */ | |
47 | #if defined(IP_PKTINFO) | |
48 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
49 | #elif defined(IP_SENDSRCADDR) | |
50 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
51 | #endif | |
52 | #ifdef HAVE_IPV6 | |
53 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
54 | #endif | |
55 | } control_u; | |
feba5c1d | 56 | |
44a2a316 SK |
57 | iov[0].iov_base = packet; |
58 | iov[0].iov_len = len; | |
59 | ||
feba5c1d SK |
60 | msg.msg_control = NULL; |
61 | msg.msg_controllen = 0; | |
44a2a316 SK |
62 | msg.msg_flags = 0; |
63 | msg.msg_name = to; | |
64 | msg.msg_namelen = sa_len(to); | |
65 | msg.msg_iov = iov; | |
66 | msg.msg_iovlen = 1; | |
feba5c1d | 67 | |
26128d27 | 68 | if (!nowild) |
44a2a316 | 69 | { |
26128d27 | 70 | struct cmsghdr *cmptr; |
feba5c1d SK |
71 | msg.msg_control = &control_u; |
72 | msg.msg_controllen = sizeof(control_u); | |
26128d27 SK |
73 | cmptr = CMSG_FIRSTHDR(&msg); |
74 | ||
75 | if (to->sa.sa_family == AF_INET) | |
76 | { | |
feba5c1d | 77 | #if defined(IP_PKTINFO) |
26128d27 SK |
78 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
79 | pkt->ipi_ifindex = 0; | |
80 | pkt->ipi_spec_dst = source->addr.addr4; | |
81 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
82 | cmptr->cmsg_level = SOL_IP; | |
83 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 84 | #elif defined(IP_SENDSRCADDR) |
26128d27 SK |
85 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
86 | *a = source->addr.addr4; | |
87 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
88 | cmptr->cmsg_level = IPPROTO_IP; | |
89 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 90 | #endif |
26128d27 | 91 | } |
26128d27 | 92 | else |
b8187c80 | 93 | #ifdef HAVE_IPV6 |
26128d27 SK |
94 | { |
95 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
96 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
97 | pkt->ipi6_addr = source->addr.addr6; | |
98 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
99 | cmptr->cmsg_type = IPV6_PKTINFO; | |
100 | cmptr->cmsg_level = IPV6_LEVEL; | |
101 | } | |
3d8df260 SK |
102 | #else |
103 | iface = 0; /* eliminate warning */ | |
44a2a316 | 104 | #endif |
26128d27 | 105 | } |
feba5c1d | 106 | |
fd9fa481 SK |
107 | retry: |
108 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 109 | { |
fd9fa481 SK |
110 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
111 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
112 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
113 | if (errno == EINVAL && msg.msg_controllen) | |
114 | { | |
115 | msg.msg_controllen = 0; | |
116 | goto retry; | |
117 | } | |
118 | if (retry_send()) | |
119 | goto retry; | |
feba5c1d | 120 | } |
9e4abcb5 | 121 | } |
44a2a316 | 122 | |
36717eee SK |
123 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
124 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
125 | |
126 | { | |
127 | /* If the query ends in the domain in one of our servers, set | |
128 | domain to point to that name. We find the largest match to allow both | |
129 | domain.org and sub.domain.org to exist. */ | |
130 | ||
131 | unsigned int namelen = strlen(qdomain); | |
132 | unsigned int matchlen = 0; | |
133 | struct server *serv; | |
134 | unsigned short flags = 0; | |
135 | ||
3be34541 | 136 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 137 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 138 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d SK |
139 | { |
140 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
141 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 142 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
143 | flags = F_NXDOMAIN; |
144 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
145 | { | |
146 | if (sflag & qtype) | |
147 | { | |
148 | flags = sflag; | |
149 | if (serv->addr.sa.sa_family == AF_INET) | |
150 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 151 | #ifdef HAVE_IPV6 |
36717eee SK |
152 | else |
153 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 154 | #endif |
36717eee SK |
155 | } |
156 | else if (!flags) | |
157 | flags = F_NOERR; | |
158 | } | |
feba5c1d SK |
159 | } |
160 | else if (serv->flags & SERV_HAS_DOMAIN) | |
161 | { | |
162 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 163 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 164 | if (namelen >= domainlen && |
b8187c80 SK |
165 | hostname_isequal(matchstart, serv->domain) && |
166 | domainlen >= matchlen && | |
cdeda28f | 167 | (domainlen == 0 || namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) |
feba5c1d SK |
168 | { |
169 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
170 | *type = SERV_HAS_DOMAIN; | |
171 | *domain = serv->domain; | |
172 | matchlen = domainlen; | |
feba5c1d | 173 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
174 | flags = F_NXDOMAIN; |
175 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 176 | { |
36717eee SK |
177 | if ((sflag | F_QUERY ) & qtype) |
178 | { | |
179 | flags = qtype; | |
180 | if (serv->addr.sa.sa_family == AF_INET) | |
181 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 182 | #ifdef HAVE_IPV6 |
36717eee SK |
183 | else |
184 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 185 | #endif |
36717eee SK |
186 | } |
187 | else if (!flags) | |
188 | flags = F_NOERR; | |
feba5c1d SK |
189 | } |
190 | } | |
191 | } | |
192 | ||
36717eee | 193 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
194 | { |
195 | if (flags & F_QUERY) | |
fd9fa481 | 196 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0, NULL, 0); |
feba5c1d | 197 | else |
fd9fa481 | 198 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0, NULL, 0); |
feba5c1d | 199 | } |
3d8df260 | 200 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
36717eee SK |
201 | flags = F_NXDOMAIN; |
202 | ||
f6b7dc47 | 203 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon)) |
c1bb8504 | 204 | flags = F_NOERR; |
feba5c1d | 205 | |
36717eee | 206 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
fd9fa481 | 207 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0, NULL, 0); |
feba5c1d SK |
208 | |
209 | return flags; | |
210 | } | |
44a2a316 | 211 | |
9e4abcb5 | 212 | /* returns new last_server */ |
3be34541 SK |
213 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
214 | struct all_addr *dst_addr, unsigned int dst_iface, | |
cdeda28f | 215 | HEADER *header, size_t plen, time_t now, struct frec *forward) |
9e4abcb5 | 216 | { |
9e4abcb5 | 217 | char *domain = NULL; |
0a852541 | 218 | int type = 0; |
9e4abcb5 | 219 | struct all_addr *addrp = NULL; |
cdeda28f | 220 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
9e4abcb5 | 221 | unsigned short flags = 0; |
cdeda28f | 222 | unsigned short gotname = extract_request(header, plen, daemon->namebuff, NULL); |
de37951c | 223 | struct server *start = NULL; |
3d8df260 SK |
224 | |
225 | /* may be no servers available. */ | |
226 | if (!daemon->servers) | |
9e4abcb5 | 227 | forward = NULL; |
b8187c80 | 228 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 229 | { |
de37951c | 230 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 231 | domain = forward->sentto->domain; |
3be34541 | 232 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 233 | { |
0a852541 | 234 | forward->forwardall = 1; |
3be34541 | 235 | daemon->last_server = NULL; |
de37951c | 236 | } |
9e4abcb5 | 237 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 238 | if (!(start = forward->sentto->next)) |
3be34541 | 239 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
240 | header->id = htons(forward->new_id); |
241 | } | |
242 | else | |
243 | { | |
244 | if (gotname) | |
36717eee | 245 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 246 | |
feba5c1d SK |
247 | if (!flags && !(forward = get_new_frec(now))) |
248 | /* table full - server failure. */ | |
249 | flags = F_NEG; | |
9e4abcb5 SK |
250 | |
251 | if (forward) | |
252 | { | |
0a852541 SK |
253 | forward->source = *udpaddr; |
254 | forward->dest = *dst_addr; | |
255 | forward->iface = dst_iface; | |
256 | forward->new_id = get_id(); | |
257 | forward->fd = udpfd; | |
258 | forward->orig_id = ntohs(header->id); | |
259 | forward->crc = crc; | |
260 | forward->forwardall = 0; | |
261 | header->id = htons(forward->new_id); | |
262 | ||
9e4abcb5 SK |
263 | /* In strict_order mode, or when using domain specific servers |
264 | always try servers in the order specified in resolv.conf, | |
265 | otherwise, use the one last known to work. */ | |
266 | ||
3be34541 SK |
267 | if (type != 0 || (daemon->options & OPT_ORDER)) |
268 | start = daemon->servers; | |
269 | else if (!(start = daemon->last_server)) | |
de37951c | 270 | { |
3be34541 | 271 | start = daemon->servers; |
0a852541 | 272 | forward->forwardall = 1; |
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 | { |
fd9fa481 | 296 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 297 | &start->addr.sa, |
fd9fa481 SK |
298 | sa_len(&start->addr)) == -1) |
299 | { | |
300 | if (retry_send()) | |
301 | continue; | |
302 | } | |
303 | else | |
9e4abcb5 | 304 | { |
cdeda28f SK |
305 | /* Keep info in case we want to re-send this packet */ |
306 | daemon->srv_save = start; | |
307 | daemon->packet_len = plen; | |
308 | ||
de37951c | 309 | if (!gotname) |
3be34541 | 310 | strcpy(daemon->namebuff, "query"); |
de37951c | 311 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 312 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
313 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
314 | NULL, 0); | |
de37951c SK |
315 | #ifdef HAVE_IPV6 |
316 | else | |
3be34541 | 317 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
318 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
319 | NULL, 0); | |
de37951c SK |
320 | #endif |
321 | forwarded = 1; | |
322 | forward->sentto = start; | |
0a852541 | 323 | if (!forward->forwardall) |
de37951c | 324 | break; |
0a852541 | 325 | forward->forwardall++; |
9e4abcb5 SK |
326 | } |
327 | } | |
328 | ||
de37951c | 329 | if (!(start = start->next)) |
3be34541 | 330 | start = daemon->servers; |
9e4abcb5 | 331 | |
de37951c | 332 | if (start == firstsentto) |
9e4abcb5 SK |
333 | break; |
334 | } | |
335 | ||
de37951c | 336 | if (forwarded) |
3be34541 | 337 | return; |
de37951c | 338 | |
9e4abcb5 SK |
339 | /* could not send on, prepare to return */ |
340 | header->id = htons(forward->orig_id); | |
341 | forward->new_id = 0; /* cancel */ | |
342 | } | |
343 | ||
344 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
345 | if (udpfd != -1) |
346 | { | |
cdeda28f | 347 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
b8187c80 SK |
348 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); |
349 | } | |
350 | ||
3be34541 | 351 | return; |
9e4abcb5 SK |
352 | } |
353 | ||
cdeda28f SK |
354 | static size_t process_reply(struct daemon *daemon, HEADER *header, time_t now, |
355 | unsigned int query_crc, struct server *server, size_t n) | |
feba5c1d | 356 | { |
36717eee | 357 | unsigned char *pheader, *sizep; |
cdeda28f SK |
358 | int munged = 0; |
359 | size_t plen; | |
360 | ||
feba5c1d SK |
361 | /* If upstream is advertising a larger UDP packet size |
362 | than we allow, trim it so that we don't get overlarge | |
363 | requests for the client. */ | |
364 | ||
36717eee | 365 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
366 | { |
367 | unsigned short udpsz; | |
36717eee | 368 | unsigned char *psave = sizep; |
feba5c1d | 369 | |
36717eee | 370 | GETSHORT(udpsz, sizep); |
3be34541 SK |
371 | if (udpsz > daemon->edns_pktsz) |
372 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
373 | } |
374 | ||
0a852541 SK |
375 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
376 | return n; | |
377 | ||
feba5c1d | 378 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
379 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
380 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 381 | { |
3d8df260 | 382 | prettyprint_addr(&server->addr, daemon->namebuff); |
b8187c80 | 383 | syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
0a852541 SK |
384 | if (!(daemon->options & OPT_LOG)) |
385 | server->flags |= SERV_WARNED_RECURSIVE; | |
386 | } | |
387 | ||
fd9fa481 SK |
388 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
389 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 390 | { |
fd9fa481 SK |
391 | munged = 1; |
392 | header->rcode = NXDOMAIN; | |
393 | header->aa = 0; | |
36717eee | 394 | } |
fd9fa481 | 395 | else |
36717eee | 396 | { |
fd9fa481 SK |
397 | if (header->rcode == NXDOMAIN && |
398 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 399 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
400 | { |
401 | /* if we forwarded a query for a locally known name (because it was for | |
402 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
403 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
404 | munged = 1; |
405 | header->aa = 1; | |
406 | header->rcode = NOERROR; | |
feba5c1d | 407 | } |
fd9fa481 | 408 | |
0a852541 SK |
409 | /* If the crc of the question section doesn't match the crc we sent, then |
410 | someone might be attempting to insert bogus values into the cache by | |
411 | sending replies containing questions and bogus answers. */ | |
412 | if (query_crc == questions_crc(header, n, daemon->namebuff)) | |
413 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 414 | } |
fd9fa481 SK |
415 | |
416 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
417 | nameserver info. */ | |
418 | ||
419 | if (munged) | |
420 | { | |
421 | header->ancount = htons(0); | |
422 | header->nscount = htons(0); | |
423 | header->arcount = htons(0); | |
424 | } | |
425 | ||
36717eee SK |
426 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
427 | sections of the packet. Find the new length here and put back pseudoheader | |
428 | if it was removed. */ | |
429 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
430 | } |
431 | ||
3be34541 SK |
432 | /* sets new last_server */ |
433 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
434 | { |
435 | /* packet from peer server, extract data for cache, and send to | |
436 | original requester */ | |
437 | struct frec *forward; | |
438 | HEADER *header; | |
de37951c SK |
439 | union mysockaddr serveraddr; |
440 | socklen_t addrlen = sizeof(serveraddr); | |
cdeda28f SK |
441 | ssize_t n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
442 | size_t nn; | |
443 | ||
444 | /* packet buffer overwritten */ | |
445 | daemon->srv_save = NULL; | |
446 | ||
de37951c SK |
447 | /* Determine the address of the server replying so that we can mark that as good */ |
448 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
449 | #ifdef HAVE_IPV6 | |
450 | if (serveraddr.sa.sa_family == AF_INET6) | |
451 | serveraddr.in6.sin6_flowinfo = htonl(0); | |
452 | #endif | |
9e4abcb5 | 453 | |
3be34541 | 454 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
455 | forward = lookup_frec(ntohs(header->id)); |
456 | ||
457 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 458 | { |
0a852541 SK |
459 | struct server *server = forward->sentto; |
460 | ||
b8187c80 SK |
461 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && forward->forwardall == 0) |
462 | /* for broken servers, attempt to send to another one. */ | |
463 | { | |
464 | unsigned char *pheader; | |
cdeda28f SK |
465 | size_t plen; |
466 | ||
b8187c80 | 467 | /* recreate query from reply */ |
cdeda28f | 468 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL); |
b8187c80 SK |
469 | header->ancount = htons(0); |
470 | header->nscount = htons(0); | |
471 | header->arcount = htons(0); | |
cdeda28f | 472 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) |
b8187c80 SK |
473 | { |
474 | forward->forwardall = 1; | |
475 | header->qr = 0; | |
476 | header->tc = 0; | |
477 | forward_query(daemon, -1, NULL, NULL, 0, header, nn, now, forward); | |
478 | return; | |
479 | } | |
480 | } | |
481 | ||
0a852541 SK |
482 | if ((forward->sentto->flags & SERV_TYPE) == 0) |
483 | { | |
484 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
485 | server = NULL; | |
486 | else | |
b8187c80 SK |
487 | { |
488 | struct server *last_server; | |
489 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
490 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
491 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
492 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
493 | { | |
494 | server = last_server; | |
495 | break; | |
496 | } | |
497 | } | |
0a852541 SK |
498 | daemon->last_server = server; |
499 | } | |
b8187c80 | 500 | |
0a852541 SK |
501 | /* If the answer is an error, keep the forward record in place in case |
502 | we get a good reply from another server. Kill it when we've | |
503 | had replies from all to avoid filling the forwarding table when | |
504 | everything is broken */ | |
505 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
506 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
b8187c80 | 507 | { |
cdeda28f | 508 | if ((nn = process_reply(daemon, header, now, forward->crc, server, (size_t)n))) |
b8187c80 SK |
509 | { |
510 | header->id = htons(forward->orig_id); | |
511 | header->ra = 1; /* recursion if available */ | |
cdeda28f | 512 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn, |
b8187c80 SK |
513 | &forward->source, &forward->dest, forward->iface); |
514 | } | |
515 | forward->new_id = 0; /* cancel */ | |
516 | } | |
9e4abcb5 | 517 | } |
9e4abcb5 | 518 | } |
44a2a316 | 519 | |
3be34541 | 520 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 521 | { |
3be34541 | 522 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 523 | union mysockaddr source_addr; |
c1bb8504 | 524 | unsigned short type; |
44a2a316 SK |
525 | struct iname *tmp; |
526 | struct all_addr dst_addr; | |
f6b7dc47 | 527 | struct in_addr netmask, dst_addr_4; |
cdeda28f SK |
528 | size_t m; |
529 | ssize_t n; | |
530 | int if_index = 0; | |
44a2a316 SK |
531 | struct iovec iov[1]; |
532 | struct msghdr msg; | |
533 | struct cmsghdr *cmptr; | |
44a2a316 SK |
534 | union { |
535 | struct cmsghdr align; /* this ensures alignment */ | |
536 | #ifdef HAVE_IPV6 | |
537 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
538 | #endif | |
539 | #if defined(IP_PKTINFO) | |
540 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
541 | #elif defined(IP_RECVDSTADDR) | |
542 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
543 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
544 | #endif | |
545 | } control_u; | |
546 | ||
cdeda28f SK |
547 | /* packet buffer overwritten */ |
548 | daemon->srv_save = NULL; | |
549 | ||
f6b7dc47 SK |
550 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
551 | { | |
552 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
553 | netmask = listen->iface->netmask; | |
554 | } | |
555 | else | |
3d8df260 SK |
556 | { |
557 | dst_addr_4.s_addr = 0; | |
558 | netmask.s_addr = 0; | |
559 | } | |
f6b7dc47 | 560 | |
3be34541 SK |
561 | iov[0].iov_base = daemon->packet; |
562 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
563 | |
564 | msg.msg_control = control_u.control; | |
565 | msg.msg_controllen = sizeof(control_u); | |
566 | msg.msg_flags = 0; | |
567 | msg.msg_name = &source_addr; | |
568 | msg.msg_namelen = sizeof(source_addr); | |
569 | msg.msg_iov = iov; | |
570 | msg.msg_iovlen = 1; | |
571 | ||
de37951c | 572 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 573 | return; |
44a2a316 | 574 | |
26128d27 SK |
575 | if (n < (int)sizeof(HEADER) || header->qr) |
576 | return; | |
577 | ||
44a2a316 SK |
578 | source_addr.sa.sa_family = listen->family; |
579 | #ifdef HAVE_IPV6 | |
580 | if (listen->family == AF_INET6) | |
26128d27 | 581 | source_addr.in6.sin6_flowinfo = htonl(0); |
44a2a316 SK |
582 | #endif |
583 | ||
26128d27 SK |
584 | if (!(daemon->options & OPT_NOWILD)) |
585 | { | |
586 | struct ifreq ifr; | |
587 | ||
588 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
589 | return; | |
44a2a316 SK |
590 | |
591 | #if defined(IP_PKTINFO) | |
26128d27 SK |
592 | if (listen->family == AF_INET) |
593 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
594 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
595 | { | |
f6b7dc47 | 596 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
597 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
598 | } | |
599 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
600 | if (listen->family == AF_INET) | |
44a2a316 | 601 | { |
26128d27 SK |
602 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
603 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 604 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
605 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
606 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 607 | } |
44a2a316 | 608 | #endif |
26128d27 | 609 | |
44a2a316 | 610 | #ifdef HAVE_IPV6 |
26128d27 SK |
611 | if (listen->family == AF_INET6) |
612 | { | |
613 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
614 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
615 | { | |
616 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
617 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
618 | } | |
619 | } | |
44a2a316 | 620 | #endif |
26128d27 SK |
621 | |
622 | /* enforce available interface configuration */ | |
623 | ||
8a911ccc | 624 | if (if_index == 0) |
3be34541 | 625 | return; |
44a2a316 | 626 | |
f6b7dc47 | 627 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
628 | { |
629 | #ifdef SIOCGIFNAME | |
630 | ifr.ifr_ifindex = if_index; | |
631 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 632 | return; |
8a911ccc SK |
633 | #else |
634 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 635 | return; |
8a911ccc | 636 | #endif |
f6b7dc47 SK |
637 | |
638 | if (listen->family == AF_INET && | |
639 | (daemon->options & OPT_LOCALISE) && | |
640 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
641 | return; | |
642 | ||
643 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
644 | } |
645 | ||
3be34541 | 646 | for (tmp = daemon->if_except; tmp; tmp = tmp->next) |
8a911ccc | 647 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
3be34541 | 648 | return; |
9e4abcb5 | 649 | |
3be34541 | 650 | if (daemon->if_names || daemon->if_addrs) |
44a2a316 | 651 | { |
3be34541 | 652 | for (tmp = daemon->if_names; tmp; tmp = tmp->next) |
8a911ccc | 653 | if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0)) |
44a2a316 SK |
654 | break; |
655 | if (!tmp) | |
3be34541 | 656 | for (tmp = daemon->if_addrs; tmp; tmp = tmp->next) |
44a2a316 SK |
657 | if (tmp->addr.sa.sa_family == listen->family) |
658 | { | |
659 | if (tmp->addr.sa.sa_family == AF_INET && | |
660 | tmp->addr.in.sin_addr.s_addr == dst_addr.addr.addr4.s_addr) | |
661 | break; | |
662 | #ifdef HAVE_IPV6 | |
663 | else if (tmp->addr.sa.sa_family == AF_INET6 && | |
664 | memcmp(&tmp->addr.in6.sin6_addr, | |
665 | &dst_addr.addr.addr6, | |
666 | sizeof(struct in6_addr)) == 0) | |
667 | break; | |
668 | #endif | |
669 | } | |
670 | if (!tmp) | |
3be34541 | 671 | return; |
44a2a316 SK |
672 | } |
673 | } | |
674 | ||
cdeda28f | 675 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
44a2a316 SK |
676 | { |
677 | if (listen->family == AF_INET) | |
3be34541 | 678 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 679 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
680 | #ifdef HAVE_IPV6 |
681 | else | |
3be34541 | 682 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 683 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
684 | #endif |
685 | } | |
686 | ||
cdeda28f | 687 | m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n, daemon, |
f6b7dc47 | 688 | dst_addr_4, netmask, now); |
44a2a316 | 689 | if (m >= 1) |
3be34541 | 690 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 691 | else |
3be34541 | 692 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
cdeda28f | 693 | header, (size_t)n, now, NULL); |
44a2a316 SK |
694 | } |
695 | ||
3d8df260 | 696 | static int read_write(int fd, unsigned char *packet, int size, int rw) |
feba5c1d | 697 | { |
cdeda28f | 698 | ssize_t n, done; |
feba5c1d SK |
699 | |
700 | for (done = 0; done < size; done += n) | |
701 | { | |
702 | retry: | |
703 | if (rw) | |
704 | n = read(fd, &packet[done], (size_t)(size - done)); | |
705 | else | |
706 | n = write(fd, &packet[done], (size_t)(size - done)); | |
707 | ||
708 | if (n == 0) | |
709 | return 0; | |
710 | else if (n == -1) | |
711 | { | |
fd9fa481 | 712 | if (retry_send()) |
feba5c1d | 713 | goto retry; |
feba5c1d SK |
714 | else |
715 | return 0; | |
716 | } | |
717 | } | |
718 | return 1; | |
719 | } | |
720 | ||
721 | /* The daemon forks before calling this: it should deal with one connection, | |
722 | blocking as neccessary, and then return. Note, need to be a bit careful | |
723 | about resources for debug mode, when the fork is suppressed: that's | |
724 | done by the caller. */ | |
3d8df260 SK |
725 | unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, |
726 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d | 727 | { |
cdeda28f SK |
728 | int size = 0; |
729 | size_t m; | |
c1bb8504 | 730 | unsigned short qtype, gotname; |
feba5c1d SK |
731 | unsigned char c1, c2; |
732 | /* Max TCP packet + slop */ | |
3d8df260 | 733 | unsigned char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 734 | HEADER *header; |
3be34541 SK |
735 | struct server *last_server; |
736 | ||
feba5c1d SK |
737 | while (1) |
738 | { | |
739 | if (!packet || | |
740 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
741 | !(size = c1 << 8 | c2) || | |
742 | !read_write(confd, packet, size, 1)) | |
743 | return packet; | |
744 | ||
745 | if (size < (int)sizeof(HEADER)) | |
746 | continue; | |
747 | ||
748 | header = (HEADER *)packet; | |
749 | ||
3be34541 | 750 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
751 | { |
752 | union mysockaddr peer_addr; | |
753 | socklen_t peer_len = sizeof(union mysockaddr); | |
754 | ||
755 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
756 | { | |
757 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 758 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 759 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
760 | #ifdef HAVE_IPV6 |
761 | else | |
3be34541 | 762 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 763 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
764 | #endif |
765 | } | |
766 | } | |
767 | ||
768 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
769 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
770 | local_addr, netmask, now); | |
feba5c1d SK |
771 | |
772 | if (m == 0) | |
773 | { | |
774 | unsigned short flags = 0; | |
feba5c1d SK |
775 | struct all_addr *addrp = NULL; |
776 | int type = 0; | |
777 | char *domain = NULL; | |
778 | ||
779 | if (gotname) | |
36717eee | 780 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 781 | |
3be34541 SK |
782 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
783 | last_server = daemon->servers; | |
784 | else | |
785 | last_server = daemon->last_server; | |
feba5c1d SK |
786 | |
787 | if (!flags && last_server) | |
788 | { | |
789 | struct server *firstsendto = NULL; | |
0a852541 SK |
790 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
791 | ||
feba5c1d SK |
792 | /* Loop round available servers until we succeed in connecting to one. |
793 | Note that this code subtley ensures that consecutive queries on this connection | |
794 | which can go to the same server, do so. */ | |
795 | while (1) | |
796 | { | |
797 | if (!firstsendto) | |
798 | firstsendto = last_server; | |
799 | else | |
800 | { | |
801 | if (!(last_server = last_server->next)) | |
3be34541 | 802 | last_server = daemon->servers; |
feba5c1d SK |
803 | |
804 | if (last_server == firstsendto) | |
805 | break; | |
806 | } | |
807 | ||
808 | /* server for wrong domain */ | |
809 | if (type != (last_server->flags & SERV_TYPE) || | |
810 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
811 | continue; | |
812 | ||
813 | if ((last_server->tcpfd == -1) && | |
814 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
815 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
816 | { | |
817 | close(last_server->tcpfd); | |
818 | last_server->tcpfd = -1; | |
819 | } | |
820 | ||
821 | if (last_server->tcpfd == -1) | |
822 | continue; | |
823 | ||
824 | c1 = size >> 8; | |
825 | c2 = size; | |
826 | ||
827 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
828 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
829 | !read_write(last_server->tcpfd, packet, size, 0) || | |
830 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
831 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
832 | { | |
833 | close(last_server->tcpfd); | |
834 | last_server->tcpfd = -1; | |
835 | continue; | |
836 | } | |
837 | ||
838 | m = (c1 << 8) | c2; | |
839 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
840 | return packet; | |
841 | ||
842 | if (!gotname) | |
3be34541 | 843 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 844 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 845 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 846 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
847 | #ifdef HAVE_IPV6 |
848 | else | |
3be34541 | 849 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 850 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
851 | #endif |
852 | ||
853 | /* There's no point in updating the cache, since this process will exit and | |
854 | lose the information after one query. We make this call for the alias and | |
855 | bogus-nxdomain side-effects. */ | |
0a852541 | 856 | m = process_reply(daemon, header, now, crc, last_server, (unsigned int)m); |
feba5c1d SK |
857 | |
858 | break; | |
859 | } | |
860 | } | |
861 | ||
862 | /* In case of local answer or no connections made. */ | |
863 | if (m == 0) | |
3be34541 | 864 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
865 | } |
866 | ||
867 | c1 = m>>8; | |
868 | c2 = m; | |
869 | if (!read_write(confd, &c1, 1, 0) || | |
870 | !read_write(confd, &c2, 1, 0) || | |
871 | !read_write(confd, packet, m, 0)) | |
872 | return packet; | |
873 | } | |
874 | } | |
875 | ||
9e4abcb5 SK |
876 | static struct frec *get_new_frec(time_t now) |
877 | { | |
878 | struct frec *f = frec_list, *oldest = NULL; | |
879 | time_t oldtime = now; | |
880 | int count = 0; | |
881 | static time_t warntime = 0; | |
882 | ||
883 | while (f) | |
884 | { | |
885 | if (f->new_id == 0) | |
886 | { | |
887 | f->time = now; | |
888 | return f; | |
889 | } | |
890 | ||
891 | if (difftime(f->time, oldtime) <= 0) | |
892 | { | |
893 | oldtime = f->time; | |
894 | oldest = f; | |
895 | } | |
896 | ||
897 | count++; | |
898 | f = f->next; | |
899 | } | |
900 | ||
901 | /* can't find empty one, use oldest if there is one | |
902 | and it's older than timeout */ | |
903 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
904 | { | |
905 | oldest->time = now; | |
906 | return oldest; | |
907 | } | |
908 | ||
909 | if (count > FTABSIZ) | |
910 | { /* limit logging rate so syslog isn't DOSed either */ | |
911 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
912 | { | |
913 | warntime = now; | |
b8187c80 | 914 | syslog(LOG_WARNING, _("forwarding table overflow: check for server loops.")); |
9e4abcb5 SK |
915 | } |
916 | return NULL; | |
917 | } | |
918 | ||
919 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
920 | { | |
921 | f->next = frec_list; | |
922 | f->time = now; | |
923 | frec_list = f; | |
924 | } | |
925 | return f; /* OK if malloc fails and this is NULL */ | |
926 | } | |
927 | ||
928 | static struct frec *lookup_frec(unsigned short id) | |
929 | { | |
930 | struct frec *f; | |
931 | ||
932 | for(f = frec_list; f; f = f->next) | |
933 | if (f->new_id == id) | |
934 | return f; | |
935 | ||
936 | return NULL; | |
937 | } | |
938 | ||
939 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
940 | union mysockaddr *addr, |
941 | unsigned int crc) | |
9e4abcb5 | 942 | { |
feba5c1d SK |
943 | struct frec *f; |
944 | ||
9e4abcb5 SK |
945 | for(f = frec_list; f; f = f->next) |
946 | if (f->new_id && | |
947 | f->orig_id == id && | |
fd9fa481 | 948 | f->crc == crc && |
9e4abcb5 SK |
949 | sockaddr_isequal(&f->source, addr)) |
950 | return f; | |
951 | ||
952 | return NULL; | |
953 | } | |
954 | ||
955 | ||
956 | /* return unique random ids between 1 and 65535 */ | |
957 | static unsigned short get_id(void) | |
958 | { | |
959 | unsigned short ret = 0; | |
960 | ||
961 | while (ret == 0) | |
962 | { | |
963 | ret = rand16(); | |
964 | ||
965 | /* scrap ids already in use */ | |
966 | if ((ret != 0) && lookup_frec(ret)) | |
967 | ret = 0; | |
968 | } | |
969 | ||
970 | return ret; | |
971 | } | |
972 | ||
973 | ||
974 | ||
975 | ||
976 |