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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 | ||
9e4abcb5 SK |
13 | #include "dnsmasq.h" |
14 | ||
849a8357 | 15 | static struct frec *frec_list = NULL; |
9e4abcb5 | 16 | |
208b65c5 | 17 | static struct frec *get_new_frec(struct daemon *daemon, time_t now); |
9e4abcb5 SK |
18 | static struct frec *lookup_frec(unsigned short id); |
19 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
20 | union mysockaddr *addr, |
21 | unsigned int crc); | |
9e4abcb5 SK |
22 | static unsigned short get_id(void); |
23 | ||
9e4abcb5 | 24 | |
44a2a316 SK |
25 | /* Send a UDP packet with it's source address set as "source" |
26 | unless nowild is true, when we just send it with the kernel default */ | |
cdeda28f | 27 | static void send_from(int fd, int nowild, char *packet, size_t len, |
dfa666f2 SK |
28 | union mysockaddr *to, struct all_addr *source, |
29 | unsigned int iface) | |
9e4abcb5 | 30 | { |
44a2a316 SK |
31 | struct msghdr msg; |
32 | struct iovec iov[1]; | |
44a2a316 SK |
33 | union { |
34 | struct cmsghdr align; /* this ensures alignment */ | |
5e9e0efb | 35 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 SK |
36 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
37 | #elif defined(IP_SENDSRCADDR) | |
38 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
39 | #endif | |
40 | #ifdef HAVE_IPV6 | |
41 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
42 | #endif | |
43 | } control_u; | |
feba5c1d | 44 | |
44a2a316 SK |
45 | iov[0].iov_base = packet; |
46 | iov[0].iov_len = len; | |
47 | ||
feba5c1d SK |
48 | msg.msg_control = NULL; |
49 | msg.msg_controllen = 0; | |
44a2a316 SK |
50 | msg.msg_flags = 0; |
51 | msg.msg_name = to; | |
52 | msg.msg_namelen = sa_len(to); | |
53 | msg.msg_iov = iov; | |
54 | msg.msg_iovlen = 1; | |
feba5c1d | 55 | |
26128d27 | 56 | if (!nowild) |
44a2a316 | 57 | { |
26128d27 | 58 | struct cmsghdr *cmptr; |
feba5c1d SK |
59 | msg.msg_control = &control_u; |
60 | msg.msg_controllen = sizeof(control_u); | |
26128d27 SK |
61 | cmptr = CMSG_FIRSTHDR(&msg); |
62 | ||
63 | if (to->sa.sa_family == AF_INET) | |
64 | { | |
5e9e0efb | 65 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
66 | struct in_pktinfo *pkt = (struct in_pktinfo *)CMSG_DATA(cmptr); |
67 | pkt->ipi_ifindex = 0; | |
68 | pkt->ipi_spec_dst = source->addr.addr4; | |
69 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
70 | cmptr->cmsg_level = SOL_IP; | |
71 | cmptr->cmsg_type = IP_PKTINFO; | |
44a2a316 | 72 | #elif defined(IP_SENDSRCADDR) |
26128d27 SK |
73 | struct in_addr *a = (struct in_addr *)CMSG_DATA(cmptr); |
74 | *a = source->addr.addr4; | |
75 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
76 | cmptr->cmsg_level = IPPROTO_IP; | |
77 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
44a2a316 | 78 | #endif |
26128d27 | 79 | } |
26128d27 | 80 | else |
b8187c80 | 81 | #ifdef HAVE_IPV6 |
26128d27 SK |
82 | { |
83 | struct in6_pktinfo *pkt = (struct in6_pktinfo *)CMSG_DATA(cmptr); | |
84 | pkt->ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
85 | pkt->ipi6_addr = source->addr.addr6; | |
86 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
87 | cmptr->cmsg_type = IPV6_PKTINFO; | |
88 | cmptr->cmsg_level = IPV6_LEVEL; | |
89 | } | |
3d8df260 SK |
90 | #else |
91 | iface = 0; /* eliminate warning */ | |
44a2a316 | 92 | #endif |
26128d27 | 93 | } |
feba5c1d | 94 | |
fd9fa481 SK |
95 | retry: |
96 | if (sendmsg(fd, &msg, 0) == -1) | |
feba5c1d | 97 | { |
fd9fa481 SK |
98 | /* certain Linux kernels seem to object to setting the source address in the IPv6 stack |
99 | by returning EINVAL from sendmsg. In that case, try again without setting the | |
100 | source address, since it will nearly alway be correct anyway. IPv6 stinks. */ | |
101 | if (errno == EINVAL && msg.msg_controllen) | |
102 | { | |
103 | msg.msg_controllen = 0; | |
104 | goto retry; | |
105 | } | |
106 | if (retry_send()) | |
107 | goto retry; | |
feba5c1d | 108 | } |
9e4abcb5 | 109 | } |
44a2a316 | 110 | |
36717eee SK |
111 | static unsigned short search_servers(struct daemon *daemon, time_t now, struct all_addr **addrpp, |
112 | unsigned short qtype, char *qdomain, int *type, char **domain) | |
feba5c1d SK |
113 | |
114 | { | |
115 | /* If the query ends in the domain in one of our servers, set | |
116 | domain to point to that name. We find the largest match to allow both | |
117 | domain.org and sub.domain.org to exist. */ | |
118 | ||
119 | unsigned int namelen = strlen(qdomain); | |
120 | unsigned int matchlen = 0; | |
121 | struct server *serv; | |
122 | unsigned short flags = 0; | |
123 | ||
3be34541 | 124 | for (serv = daemon->servers; serv; serv=serv->next) |
feba5c1d | 125 | /* domain matches take priority over NODOTS matches */ |
3d8df260 | 126 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) |
feba5c1d SK |
127 | { |
128 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
129 | *type = SERV_FOR_NODOTS; | |
feba5c1d | 130 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
131 | flags = F_NXDOMAIN; |
132 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
133 | { | |
134 | if (sflag & qtype) | |
135 | { | |
136 | flags = sflag; | |
137 | if (serv->addr.sa.sa_family == AF_INET) | |
138 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 139 | #ifdef HAVE_IPV6 |
36717eee SK |
140 | else |
141 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 142 | #endif |
36717eee SK |
143 | } |
144 | else if (!flags) | |
145 | flags = F_NOERR; | |
146 | } | |
feba5c1d SK |
147 | } |
148 | else if (serv->flags & SERV_HAS_DOMAIN) | |
149 | { | |
150 | unsigned int domainlen = strlen(serv->domain); | |
b8187c80 | 151 | char *matchstart = qdomain + namelen - domainlen; |
feba5c1d | 152 | if (namelen >= domainlen && |
b8187c80 SK |
153 | hostname_isequal(matchstart, serv->domain) && |
154 | domainlen >= matchlen && | |
cdeda28f | 155 | (domainlen == 0 || namelen == domainlen || *(serv->domain) == '.' || *(matchstart-1) == '.' )) |
feba5c1d SK |
156 | { |
157 | unsigned short sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
158 | *type = SERV_HAS_DOMAIN; | |
159 | *domain = serv->domain; | |
160 | matchlen = domainlen; | |
feba5c1d | 161 | if (serv->flags & SERV_NO_ADDR) |
36717eee SK |
162 | flags = F_NXDOMAIN; |
163 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
feba5c1d | 164 | { |
36717eee SK |
165 | if ((sflag | F_QUERY ) & qtype) |
166 | { | |
167 | flags = qtype; | |
168 | if (serv->addr.sa.sa_family == AF_INET) | |
169 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
feba5c1d | 170 | #ifdef HAVE_IPV6 |
36717eee SK |
171 | else |
172 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
feba5c1d | 173 | #endif |
36717eee SK |
174 | } |
175 | else if (!flags) | |
176 | flags = F_NOERR; | |
feba5c1d SK |
177 | } |
178 | } | |
179 | } | |
180 | ||
36717eee | 181 | if (flags & ~(F_NOERR | F_NXDOMAIN)) /* flags set here means a literal found */ |
feba5c1d SK |
182 | { |
183 | if (flags & F_QUERY) | |
fd9fa481 | 184 | log_query(F_CONFIG | F_FORWARD | F_NEG, qdomain, NULL, 0, NULL, 0); |
feba5c1d | 185 | else |
fd9fa481 | 186 | log_query(F_CONFIG | F_FORWARD | flags, qdomain, *addrpp, 0, NULL, 0); |
feba5c1d | 187 | } |
3d8df260 | 188 | else if (qtype && (daemon->options & OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) |
36717eee SK |
189 | flags = F_NXDOMAIN; |
190 | ||
f6b7dc47 | 191 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now, daemon)) |
c1bb8504 | 192 | flags = F_NOERR; |
feba5c1d | 193 | |
36717eee | 194 | if (flags == F_NXDOMAIN || flags == F_NOERR) |
fd9fa481 | 195 | log_query(F_CONFIG | F_FORWARD | F_NEG | qtype | (flags & F_NXDOMAIN), qdomain, NULL, 0, NULL, 0); |
feba5c1d SK |
196 | |
197 | return flags; | |
198 | } | |
44a2a316 | 199 | |
9e4abcb5 | 200 | /* returns new last_server */ |
3be34541 SK |
201 | static void forward_query(struct daemon *daemon, int udpfd, union mysockaddr *udpaddr, |
202 | struct all_addr *dst_addr, unsigned int dst_iface, | |
cdeda28f | 203 | HEADER *header, size_t plen, time_t now, struct frec *forward) |
9e4abcb5 | 204 | { |
9e4abcb5 | 205 | char *domain = NULL; |
0a852541 | 206 | int type = 0; |
9e4abcb5 | 207 | struct all_addr *addrp = NULL; |
cdeda28f | 208 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); |
9e4abcb5 | 209 | unsigned short flags = 0; |
cdeda28f | 210 | unsigned short gotname = extract_request(header, plen, daemon->namebuff, NULL); |
de37951c | 211 | struct server *start = NULL; |
3d8df260 SK |
212 | |
213 | /* may be no servers available. */ | |
214 | if (!daemon->servers) | |
9e4abcb5 | 215 | forward = NULL; |
b8187c80 | 216 | else if (forward || (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, crc))) |
9e4abcb5 | 217 | { |
de37951c | 218 | /* retry on existing query, send to all available servers */ |
9e4abcb5 | 219 | domain = forward->sentto->domain; |
3be34541 | 220 | if (!(daemon->options & OPT_ORDER)) |
de37951c | 221 | { |
0a852541 | 222 | forward->forwardall = 1; |
3be34541 | 223 | daemon->last_server = NULL; |
de37951c | 224 | } |
9e4abcb5 | 225 | type = forward->sentto->flags & SERV_TYPE; |
de37951c | 226 | if (!(start = forward->sentto->next)) |
3be34541 | 227 | start = daemon->servers; /* at end of list, recycle */ |
9e4abcb5 SK |
228 | header->id = htons(forward->new_id); |
229 | } | |
230 | else | |
231 | { | |
232 | if (gotname) | |
36717eee | 233 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
9e4abcb5 | 234 | |
208b65c5 | 235 | if (!flags && !(forward = get_new_frec(daemon, now))) |
feba5c1d SK |
236 | /* table full - server failure. */ |
237 | flags = F_NEG; | |
9e4abcb5 SK |
238 | |
239 | if (forward) | |
240 | { | |
0a852541 SK |
241 | forward->source = *udpaddr; |
242 | forward->dest = *dst_addr; | |
243 | forward->iface = dst_iface; | |
244 | forward->new_id = get_id(); | |
245 | forward->fd = udpfd; | |
246 | forward->orig_id = ntohs(header->id); | |
247 | forward->crc = crc; | |
248 | forward->forwardall = 0; | |
249 | header->id = htons(forward->new_id); | |
250 | ||
9e4abcb5 SK |
251 | /* In strict_order mode, or when using domain specific servers |
252 | always try servers in the order specified in resolv.conf, | |
253 | otherwise, use the one last known to work. */ | |
254 | ||
3be34541 SK |
255 | if (type != 0 || (daemon->options & OPT_ORDER)) |
256 | start = daemon->servers; | |
257 | else if (!(start = daemon->last_server)) | |
de37951c | 258 | { |
3be34541 | 259 | start = daemon->servers; |
0a852541 | 260 | forward->forwardall = 1; |
de37951c | 261 | } |
9e4abcb5 SK |
262 | } |
263 | } | |
feba5c1d | 264 | |
9e4abcb5 SK |
265 | /* check for send errors here (no route to host) |
266 | if we fail to send to all nameservers, send back an error | |
267 | packet straight away (helps modem users when offline) */ | |
268 | ||
269 | if (!flags && forward) | |
270 | { | |
de37951c SK |
271 | struct server *firstsentto = start; |
272 | int forwarded = 0; | |
273 | ||
9e4abcb5 SK |
274 | while (1) |
275 | { | |
9e4abcb5 SK |
276 | /* only send to servers dealing with our domain. |
277 | domain may be NULL, in which case server->domain | |
278 | must be NULL also. */ | |
279 | ||
de37951c | 280 | if (type == (start->flags & SERV_TYPE) && |
fd9fa481 SK |
281 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && |
282 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
9e4abcb5 | 283 | { |
fd9fa481 | 284 | if (sendto(start->sfd->fd, (char *)header, plen, 0, |
feba5c1d | 285 | &start->addr.sa, |
fd9fa481 SK |
286 | sa_len(&start->addr)) == -1) |
287 | { | |
288 | if (retry_send()) | |
289 | continue; | |
290 | } | |
291 | else | |
9e4abcb5 | 292 | { |
cdeda28f SK |
293 | /* Keep info in case we want to re-send this packet */ |
294 | daemon->srv_save = start; | |
295 | daemon->packet_len = plen; | |
296 | ||
de37951c | 297 | if (!gotname) |
3be34541 | 298 | strcpy(daemon->namebuff, "query"); |
de37951c | 299 | if (start->addr.sa.sa_family == AF_INET) |
3be34541 | 300 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
301 | (struct all_addr *)&start->addr.in.sin_addr, 0, |
302 | NULL, 0); | |
de37951c SK |
303 | #ifdef HAVE_IPV6 |
304 | else | |
3be34541 | 305 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 SK |
306 | (struct all_addr *)&start->addr.in6.sin6_addr, 0, |
307 | NULL, 0); | |
de37951c SK |
308 | #endif |
309 | forwarded = 1; | |
310 | forward->sentto = start; | |
0a852541 | 311 | if (!forward->forwardall) |
de37951c | 312 | break; |
0a852541 | 313 | forward->forwardall++; |
9e4abcb5 SK |
314 | } |
315 | } | |
316 | ||
de37951c | 317 | if (!(start = start->next)) |
3be34541 | 318 | start = daemon->servers; |
9e4abcb5 | 319 | |
de37951c | 320 | if (start == firstsentto) |
9e4abcb5 SK |
321 | break; |
322 | } | |
323 | ||
de37951c | 324 | if (forwarded) |
3be34541 | 325 | return; |
de37951c | 326 | |
9e4abcb5 SK |
327 | /* could not send on, prepare to return */ |
328 | header->id = htons(forward->orig_id); | |
329 | forward->new_id = 0; /* cancel */ | |
330 | } | |
331 | ||
332 | /* could not send on, return empty answer or address if known for whole domain */ | |
b8187c80 SK |
333 | if (udpfd != -1) |
334 | { | |
cdeda28f | 335 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); |
b8187c80 SK |
336 | send_from(udpfd, daemon->options & OPT_NOWILD, (char *)header, plen, udpaddr, dst_addr, dst_iface); |
337 | } | |
338 | ||
3be34541 | 339 | return; |
9e4abcb5 SK |
340 | } |
341 | ||
cdeda28f | 342 | static size_t process_reply(struct daemon *daemon, HEADER *header, time_t now, |
5e9e0efb | 343 | unsigned int query_crc, struct server *server, size_t n) |
feba5c1d | 344 | { |
36717eee | 345 | unsigned char *pheader, *sizep; |
cdeda28f SK |
346 | int munged = 0; |
347 | size_t plen; | |
348 | ||
feba5c1d SK |
349 | /* If upstream is advertising a larger UDP packet size |
350 | than we allow, trim it so that we don't get overlarge | |
351 | requests for the client. */ | |
352 | ||
36717eee | 353 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep))) |
feba5c1d SK |
354 | { |
355 | unsigned short udpsz; | |
36717eee | 356 | unsigned char *psave = sizep; |
feba5c1d | 357 | |
36717eee | 358 | GETSHORT(udpsz, sizep); |
3be34541 SK |
359 | if (udpsz > daemon->edns_pktsz) |
360 | PUTSHORT(daemon->edns_pktsz, psave); | |
feba5c1d SK |
361 | } |
362 | ||
0a852541 SK |
363 | if (header->opcode != QUERY || (header->rcode != NOERROR && header->rcode != NXDOMAIN)) |
364 | return n; | |
365 | ||
feba5c1d | 366 | /* Complain loudly if the upstream server is non-recursive. */ |
0a852541 SK |
367 | if (!header->ra && header->rcode == NOERROR && ntohs(header->ancount) == 0 && |
368 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
feba5c1d | 369 | { |
3d8df260 | 370 | prettyprint_addr(&server->addr, daemon->namebuff); |
b8187c80 | 371 | syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); |
0a852541 SK |
372 | if (!(daemon->options & OPT_LOG)) |
373 | server->flags |= SERV_WARNED_RECURSIVE; | |
374 | } | |
375 | ||
fd9fa481 SK |
376 | if (daemon->bogus_addr && header->rcode != NXDOMAIN && |
377 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
feba5c1d | 378 | { |
fd9fa481 SK |
379 | munged = 1; |
380 | header->rcode = NXDOMAIN; | |
381 | header->aa = 0; | |
36717eee | 382 | } |
fd9fa481 | 383 | else |
36717eee | 384 | { |
fd9fa481 SK |
385 | if (header->rcode == NXDOMAIN && |
386 | extract_request(header, n, daemon->namebuff, NULL) && | |
f6b7dc47 | 387 | check_for_local_domain(daemon->namebuff, now, daemon)) |
36717eee SK |
388 | { |
389 | /* if we forwarded a query for a locally known name (because it was for | |
390 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
391 | since we know that the domain exists, even if upstream doesn't */ | |
fd9fa481 SK |
392 | munged = 1; |
393 | header->aa = 1; | |
394 | header->rcode = NOERROR; | |
feba5c1d | 395 | } |
fd9fa481 | 396 | |
0a852541 SK |
397 | /* If the crc of the question section doesn't match the crc we sent, then |
398 | someone might be attempting to insert bogus values into the cache by | |
399 | sending replies containing questions and bogus answers. */ | |
400 | if (query_crc == questions_crc(header, n, daemon->namebuff)) | |
401 | extract_addresses(header, n, daemon->namebuff, now, daemon); | |
feba5c1d | 402 | } |
fd9fa481 SK |
403 | |
404 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
405 | nameserver info. */ | |
406 | ||
407 | if (munged) | |
408 | { | |
409 | header->ancount = htons(0); | |
410 | header->nscount = htons(0); | |
411 | header->arcount = htons(0); | |
412 | } | |
413 | ||
36717eee SK |
414 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide |
415 | sections of the packet. Find the new length here and put back pseudoheader | |
416 | if it was removed. */ | |
417 | return resize_packet(header, n, pheader, plen); | |
feba5c1d SK |
418 | } |
419 | ||
3be34541 SK |
420 | /* sets new last_server */ |
421 | void reply_query(struct serverfd *sfd, struct daemon *daemon, time_t now) | |
9e4abcb5 SK |
422 | { |
423 | /* packet from peer server, extract data for cache, and send to | |
424 | original requester */ | |
425 | struct frec *forward; | |
426 | HEADER *header; | |
de37951c SK |
427 | union mysockaddr serveraddr; |
428 | socklen_t addrlen = sizeof(serveraddr); | |
cdeda28f SK |
429 | ssize_t n = recvfrom(sfd->fd, daemon->packet, daemon->edns_pktsz, 0, &serveraddr.sa, &addrlen); |
430 | size_t nn; | |
431 | ||
432 | /* packet buffer overwritten */ | |
433 | daemon->srv_save = NULL; | |
434 | ||
de37951c SK |
435 | /* Determine the address of the server replying so that we can mark that as good */ |
436 | serveraddr.sa.sa_family = sfd->source_addr.sa.sa_family; | |
437 | #ifdef HAVE_IPV6 | |
438 | if (serveraddr.sa.sa_family == AF_INET6) | |
5e9e0efb | 439 | serveraddr.in6.sin6_flowinfo = 0; |
de37951c | 440 | #endif |
9e4abcb5 | 441 | |
3be34541 | 442 | header = (HEADER *)daemon->packet; |
fd9fa481 SK |
443 | forward = lookup_frec(ntohs(header->id)); |
444 | ||
445 | if (n >= (int)sizeof(HEADER) && header->qr && forward) | |
9e4abcb5 | 446 | { |
0a852541 SK |
447 | struct server *server = forward->sentto; |
448 | ||
b8187c80 SK |
449 | if ((header->rcode == SERVFAIL || header->rcode == REFUSED) && forward->forwardall == 0) |
450 | /* for broken servers, attempt to send to another one. */ | |
451 | { | |
452 | unsigned char *pheader; | |
cdeda28f SK |
453 | size_t plen; |
454 | ||
b8187c80 | 455 | /* recreate query from reply */ |
cdeda28f | 456 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL); |
b8187c80 SK |
457 | header->ancount = htons(0); |
458 | header->nscount = htons(0); | |
459 | header->arcount = htons(0); | |
cdeda28f | 460 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) |
b8187c80 SK |
461 | { |
462 | forward->forwardall = 1; | |
463 | header->qr = 0; | |
464 | header->tc = 0; | |
465 | forward_query(daemon, -1, NULL, NULL, 0, header, nn, now, forward); | |
466 | return; | |
467 | } | |
468 | } | |
469 | ||
0a852541 SK |
470 | if ((forward->sentto->flags & SERV_TYPE) == 0) |
471 | { | |
472 | if (header->rcode == SERVFAIL || header->rcode == REFUSED) | |
473 | server = NULL; | |
474 | else | |
b8187c80 SK |
475 | { |
476 | struct server *last_server; | |
477 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
478 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
479 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
480 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
481 | { | |
482 | server = last_server; | |
483 | break; | |
484 | } | |
485 | } | |
0a852541 SK |
486 | daemon->last_server = server; |
487 | } | |
b8187c80 | 488 | |
0a852541 SK |
489 | /* If the answer is an error, keep the forward record in place in case |
490 | we get a good reply from another server. Kill it when we've | |
491 | had replies from all to avoid filling the forwarding table when | |
492 | everything is broken */ | |
493 | if (forward->forwardall == 0 || --forward->forwardall == 1 || | |
494 | (header->rcode != REFUSED && header->rcode != SERVFAIL)) | |
b8187c80 | 495 | { |
cdeda28f | 496 | if ((nn = process_reply(daemon, header, now, forward->crc, server, (size_t)n))) |
b8187c80 SK |
497 | { |
498 | header->id = htons(forward->orig_id); | |
499 | header->ra = 1; /* recursion if available */ | |
cdeda28f | 500 | send_from(forward->fd, daemon->options & OPT_NOWILD, daemon->packet, nn, |
b8187c80 SK |
501 | &forward->source, &forward->dest, forward->iface); |
502 | } | |
503 | forward->new_id = 0; /* cancel */ | |
504 | } | |
9e4abcb5 | 505 | } |
9e4abcb5 | 506 | } |
44a2a316 | 507 | |
3be34541 | 508 | void receive_query(struct listener *listen, struct daemon *daemon, time_t now) |
44a2a316 | 509 | { |
3be34541 | 510 | HEADER *header = (HEADER *)daemon->packet; |
44a2a316 | 511 | union mysockaddr source_addr; |
c1bb8504 | 512 | unsigned short type; |
44a2a316 | 513 | struct all_addr dst_addr; |
f6b7dc47 | 514 | struct in_addr netmask, dst_addr_4; |
cdeda28f SK |
515 | size_t m; |
516 | ssize_t n; | |
517 | int if_index = 0; | |
44a2a316 SK |
518 | struct iovec iov[1]; |
519 | struct msghdr msg; | |
520 | struct cmsghdr *cmptr; | |
44a2a316 SK |
521 | union { |
522 | struct cmsghdr align; /* this ensures alignment */ | |
523 | #ifdef HAVE_IPV6 | |
524 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
525 | #endif | |
5e9e0efb | 526 | #if defined(HAVE_LINUX_NETWORK) |
44a2a316 SK |
527 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; |
528 | #elif defined(IP_RECVDSTADDR) | |
529 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
530 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
531 | #endif | |
532 | } control_u; | |
533 | ||
cdeda28f SK |
534 | /* packet buffer overwritten */ |
535 | daemon->srv_save = NULL; | |
536 | ||
f6b7dc47 SK |
537 | if (listen->family == AF_INET && (daemon->options & OPT_NOWILD)) |
538 | { | |
539 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
540 | netmask = listen->iface->netmask; | |
541 | } | |
542 | else | |
3d8df260 SK |
543 | { |
544 | dst_addr_4.s_addr = 0; | |
545 | netmask.s_addr = 0; | |
546 | } | |
f6b7dc47 | 547 | |
3be34541 SK |
548 | iov[0].iov_base = daemon->packet; |
549 | iov[0].iov_len = daemon->edns_pktsz; | |
44a2a316 SK |
550 | |
551 | msg.msg_control = control_u.control; | |
552 | msg.msg_controllen = sizeof(control_u); | |
553 | msg.msg_flags = 0; | |
554 | msg.msg_name = &source_addr; | |
555 | msg.msg_namelen = sizeof(source_addr); | |
556 | msg.msg_iov = iov; | |
557 | msg.msg_iovlen = 1; | |
558 | ||
de37951c | 559 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) |
3be34541 | 560 | return; |
44a2a316 | 561 | |
5e9e0efb SK |
562 | if (n < (int)sizeof(HEADER) || |
563 | (msg.msg_flags & MSG_TRUNC) || | |
564 | header->qr) | |
26128d27 SK |
565 | return; |
566 | ||
44a2a316 SK |
567 | source_addr.sa.sa_family = listen->family; |
568 | #ifdef HAVE_IPV6 | |
569 | if (listen->family == AF_INET6) | |
5e9e0efb | 570 | source_addr.in6.sin6_flowinfo = 0; |
44a2a316 SK |
571 | #endif |
572 | ||
26128d27 SK |
573 | if (!(daemon->options & OPT_NOWILD)) |
574 | { | |
575 | struct ifreq ifr; | |
576 | ||
577 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
578 | return; | |
44a2a316 | 579 | |
5e9e0efb | 580 | #if defined(HAVE_LINUX_NETWORK) |
26128d27 SK |
581 | if (listen->family == AF_INET) |
582 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
583 | if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO) | |
584 | { | |
f6b7dc47 | 585 | dst_addr_4 = dst_addr.addr.addr4 = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_spec_dst; |
26128d27 SK |
586 | if_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex; |
587 | } | |
588 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
589 | if (listen->family == AF_INET) | |
44a2a316 | 590 | { |
26128d27 SK |
591 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) |
592 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
f6b7dc47 | 593 | dst_addr_4 = dst_addr.addr.addr4 = *((struct in_addr *)CMSG_DATA(cmptr)); |
26128d27 SK |
594 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) |
595 | if_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index; | |
44a2a316 | 596 | } |
44a2a316 | 597 | #endif |
26128d27 | 598 | |
44a2a316 | 599 | #ifdef HAVE_IPV6 |
26128d27 SK |
600 | if (listen->family == AF_INET6) |
601 | { | |
602 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
603 | if (cmptr->cmsg_level == IPV6_LEVEL && cmptr->cmsg_type == IPV6_PKTINFO) | |
604 | { | |
605 | dst_addr.addr.addr6 = ((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_addr; | |
606 | if_index =((struct in6_pktinfo *)CMSG_DATA(cmptr))->ipi6_ifindex; | |
607 | } | |
608 | } | |
44a2a316 | 609 | #endif |
26128d27 SK |
610 | |
611 | /* enforce available interface configuration */ | |
612 | ||
8a911ccc | 613 | if (if_index == 0) |
3be34541 | 614 | return; |
44a2a316 | 615 | |
f6b7dc47 | 616 | if (daemon->if_except || daemon->if_names || (daemon->options & OPT_LOCALISE)) |
8a911ccc SK |
617 | { |
618 | #ifdef SIOCGIFNAME | |
619 | ifr.ifr_ifindex = if_index; | |
620 | if (ioctl(listen->fd, SIOCGIFNAME, &ifr) == -1) | |
3be34541 | 621 | return; |
8a911ccc SK |
622 | #else |
623 | if (!if_indextoname(if_index, ifr.ifr_name)) | |
3be34541 | 624 | return; |
8a911ccc | 625 | #endif |
f6b7dc47 SK |
626 | |
627 | if (listen->family == AF_INET && | |
628 | (daemon->options & OPT_LOCALISE) && | |
629 | ioctl(listen->fd, SIOCGIFNETMASK, &ifr) == -1) | |
630 | return; | |
631 | ||
632 | netmask = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr; | |
8a911ccc SK |
633 | } |
634 | ||
5e9e0efb SK |
635 | if (!iface_check(daemon, listen->family, &dst_addr, ifr.ifr_name)) |
636 | return; | |
44a2a316 SK |
637 | } |
638 | ||
cdeda28f | 639 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) |
44a2a316 SK |
640 | { |
641 | if (listen->family == AF_INET) | |
3be34541 | 642 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 643 | (struct all_addr *)&source_addr.in.sin_addr, type, NULL, 0); |
44a2a316 SK |
644 | #ifdef HAVE_IPV6 |
645 | else | |
3be34541 | 646 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 647 | (struct all_addr *)&source_addr.in6.sin6_addr, type, NULL, 0); |
44a2a316 SK |
648 | #endif |
649 | } | |
650 | ||
cdeda28f | 651 | m = answer_request (header, ((char *) header) + PACKETSZ, (size_t)n, daemon, |
f6b7dc47 | 652 | dst_addr_4, netmask, now); |
44a2a316 | 653 | if (m >= 1) |
3be34541 | 654 | send_from(listen->fd, daemon->options & OPT_NOWILD, (char *)header, m, &source_addr, &dst_addr, if_index); |
44a2a316 | 655 | else |
3be34541 | 656 | forward_query(daemon, listen->fd, &source_addr, &dst_addr, if_index, |
cdeda28f | 657 | header, (size_t)n, now, NULL); |
44a2a316 SK |
658 | } |
659 | ||
3d8df260 | 660 | static int read_write(int fd, unsigned char *packet, int size, int rw) |
feba5c1d | 661 | { |
cdeda28f | 662 | ssize_t n, done; |
feba5c1d SK |
663 | |
664 | for (done = 0; done < size; done += n) | |
665 | { | |
666 | retry: | |
667 | if (rw) | |
668 | n = read(fd, &packet[done], (size_t)(size - done)); | |
669 | else | |
670 | n = write(fd, &packet[done], (size_t)(size - done)); | |
671 | ||
672 | if (n == 0) | |
673 | return 0; | |
674 | else if (n == -1) | |
675 | { | |
5e9e0efb | 676 | if (errno == EINTR) |
feba5c1d | 677 | goto retry; |
feba5c1d SK |
678 | else |
679 | return 0; | |
680 | } | |
681 | } | |
682 | return 1; | |
683 | } | |
684 | ||
685 | /* The daemon forks before calling this: it should deal with one connection, | |
686 | blocking as neccessary, and then return. Note, need to be a bit careful | |
687 | about resources for debug mode, when the fork is suppressed: that's | |
688 | done by the caller. */ | |
3d8df260 SK |
689 | unsigned char *tcp_request(struct daemon *daemon, int confd, time_t now, |
690 | struct in_addr local_addr, struct in_addr netmask) | |
feba5c1d | 691 | { |
cdeda28f SK |
692 | int size = 0; |
693 | size_t m; | |
c1bb8504 | 694 | unsigned short qtype, gotname; |
feba5c1d SK |
695 | unsigned char c1, c2; |
696 | /* Max TCP packet + slop */ | |
3d8df260 | 697 | unsigned char *packet = malloc(65536 + MAXDNAME + RRFIXEDSZ); |
feba5c1d | 698 | HEADER *header; |
3be34541 SK |
699 | struct server *last_server; |
700 | ||
feba5c1d SK |
701 | while (1) |
702 | { | |
703 | if (!packet || | |
704 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
705 | !(size = c1 << 8 | c2) || | |
706 | !read_write(confd, packet, size, 1)) | |
707 | return packet; | |
708 | ||
709 | if (size < (int)sizeof(HEADER)) | |
710 | continue; | |
711 | ||
712 | header = (HEADER *)packet; | |
713 | ||
3be34541 | 714 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) |
feba5c1d SK |
715 | { |
716 | union mysockaddr peer_addr; | |
717 | socklen_t peer_len = sizeof(union mysockaddr); | |
718 | ||
719 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) != -1) | |
720 | { | |
721 | if (peer_addr.sa.sa_family == AF_INET) | |
3be34541 | 722 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 723 | (struct all_addr *)&peer_addr.in.sin_addr, qtype, NULL, 0); |
feba5c1d SK |
724 | #ifdef HAVE_IPV6 |
725 | else | |
3be34541 | 726 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 727 | (struct all_addr *)&peer_addr.in6.sin6_addr, qtype, NULL, 0); |
feba5c1d SK |
728 | #endif |
729 | } | |
730 | } | |
731 | ||
732 | /* m > 0 if answered from cache */ | |
f6b7dc47 SK |
733 | m = answer_request(header, ((char *) header) + 65536, (unsigned int)size, daemon, |
734 | local_addr, netmask, now); | |
feba5c1d SK |
735 | |
736 | if (m == 0) | |
737 | { | |
738 | unsigned short flags = 0; | |
feba5c1d SK |
739 | struct all_addr *addrp = NULL; |
740 | int type = 0; | |
741 | char *domain = NULL; | |
742 | ||
743 | if (gotname) | |
36717eee | 744 | flags = search_servers(daemon, now, &addrp, gotname, daemon->namebuff, &type, &domain); |
feba5c1d | 745 | |
3be34541 SK |
746 | if (type != 0 || (daemon->options & OPT_ORDER) || !daemon->last_server) |
747 | last_server = daemon->servers; | |
748 | else | |
749 | last_server = daemon->last_server; | |
feba5c1d SK |
750 | |
751 | if (!flags && last_server) | |
752 | { | |
753 | struct server *firstsendto = NULL; | |
0a852541 SK |
754 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); |
755 | ||
feba5c1d SK |
756 | /* Loop round available servers until we succeed in connecting to one. |
757 | Note that this code subtley ensures that consecutive queries on this connection | |
758 | which can go to the same server, do so. */ | |
759 | while (1) | |
760 | { | |
761 | if (!firstsendto) | |
762 | firstsendto = last_server; | |
763 | else | |
764 | { | |
765 | if (!(last_server = last_server->next)) | |
3be34541 | 766 | last_server = daemon->servers; |
feba5c1d SK |
767 | |
768 | if (last_server == firstsendto) | |
769 | break; | |
770 | } | |
771 | ||
772 | /* server for wrong domain */ | |
773 | if (type != (last_server->flags & SERV_TYPE) || | |
774 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
775 | continue; | |
776 | ||
777 | if ((last_server->tcpfd == -1) && | |
778 | (last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) != -1 && | |
779 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1) | |
780 | { | |
781 | close(last_server->tcpfd); | |
782 | last_server->tcpfd = -1; | |
783 | } | |
784 | ||
785 | if (last_server->tcpfd == -1) | |
786 | continue; | |
787 | ||
788 | c1 = size >> 8; | |
789 | c2 = size; | |
790 | ||
791 | if (!read_write(last_server->tcpfd, &c1, 1, 0) || | |
792 | !read_write(last_server->tcpfd, &c2, 1, 0) || | |
793 | !read_write(last_server->tcpfd, packet, size, 0) || | |
794 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
795 | !read_write(last_server->tcpfd, &c2, 1, 1)) | |
796 | { | |
797 | close(last_server->tcpfd); | |
798 | last_server->tcpfd = -1; | |
799 | continue; | |
800 | } | |
801 | ||
802 | m = (c1 << 8) | c2; | |
803 | if (!read_write(last_server->tcpfd, packet, m, 1)) | |
804 | return packet; | |
805 | ||
806 | if (!gotname) | |
3be34541 | 807 | strcpy(daemon->namebuff, "query"); |
feba5c1d | 808 | if (last_server->addr.sa.sa_family == AF_INET) |
3be34541 | 809 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 810 | (struct all_addr *)&last_server->addr.in.sin_addr, 0, NULL, 0); |
feba5c1d SK |
811 | #ifdef HAVE_IPV6 |
812 | else | |
3be34541 | 813 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, |
fd9fa481 | 814 | (struct all_addr *)&last_server->addr.in6.sin6_addr, 0, NULL, 0); |
feba5c1d SK |
815 | #endif |
816 | ||
817 | /* There's no point in updating the cache, since this process will exit and | |
818 | lose the information after one query. We make this call for the alias and | |
819 | bogus-nxdomain side-effects. */ | |
0a852541 | 820 | m = process_reply(daemon, header, now, crc, last_server, (unsigned int)m); |
feba5c1d SK |
821 | |
822 | break; | |
823 | } | |
824 | } | |
825 | ||
826 | /* In case of local answer or no connections made. */ | |
827 | if (m == 0) | |
3be34541 | 828 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); |
feba5c1d SK |
829 | } |
830 | ||
831 | c1 = m>>8; | |
832 | c2 = m; | |
833 | if (!read_write(confd, &c1, 1, 0) || | |
834 | !read_write(confd, &c2, 1, 0) || | |
835 | !read_write(confd, packet, m, 0)) | |
836 | return packet; | |
837 | } | |
838 | } | |
839 | ||
208b65c5 | 840 | static struct frec *get_new_frec(struct daemon *daemon, time_t now) |
9e4abcb5 SK |
841 | { |
842 | struct frec *f = frec_list, *oldest = NULL; | |
843 | time_t oldtime = now; | |
844 | int count = 0; | |
845 | static time_t warntime = 0; | |
846 | ||
847 | while (f) | |
848 | { | |
849 | if (f->new_id == 0) | |
850 | { | |
851 | f->time = now; | |
852 | return f; | |
853 | } | |
854 | ||
855 | if (difftime(f->time, oldtime) <= 0) | |
856 | { | |
857 | oldtime = f->time; | |
858 | oldest = f; | |
859 | } | |
860 | ||
861 | count++; | |
862 | f = f->next; | |
863 | } | |
864 | ||
865 | /* can't find empty one, use oldest if there is one | |
866 | and it's older than timeout */ | |
867 | if (oldest && difftime(now, oldtime) > TIMEOUT) | |
868 | { | |
869 | oldest->time = now; | |
870 | return oldest; | |
871 | } | |
872 | ||
208b65c5 | 873 | if (count > daemon->ftabsize) |
9e4abcb5 SK |
874 | { /* limit logging rate so syslog isn't DOSed either */ |
875 | if (!warntime || difftime(now, warntime) > LOGRATE) | |
876 | { | |
877 | warntime = now; | |
b8187c80 | 878 | syslog(LOG_WARNING, _("forwarding table overflow: check for server loops.")); |
9e4abcb5 SK |
879 | } |
880 | return NULL; | |
881 | } | |
882 | ||
883 | if ((f = (struct frec *)malloc(sizeof(struct frec)))) | |
884 | { | |
885 | f->next = frec_list; | |
886 | f->time = now; | |
5e9e0efb | 887 | f->new_id = 0; |
9e4abcb5 SK |
888 | frec_list = f; |
889 | } | |
890 | return f; /* OK if malloc fails and this is NULL */ | |
891 | } | |
892 | ||
893 | static struct frec *lookup_frec(unsigned short id) | |
894 | { | |
895 | struct frec *f; | |
896 | ||
897 | for(f = frec_list; f; f = f->next) | |
898 | if (f->new_id == id) | |
899 | return f; | |
900 | ||
901 | return NULL; | |
902 | } | |
903 | ||
904 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
fd9fa481 SK |
905 | union mysockaddr *addr, |
906 | unsigned int crc) | |
9e4abcb5 | 907 | { |
feba5c1d SK |
908 | struct frec *f; |
909 | ||
9e4abcb5 SK |
910 | for(f = frec_list; f; f = f->next) |
911 | if (f->new_id && | |
912 | f->orig_id == id && | |
fd9fa481 | 913 | f->crc == crc && |
9e4abcb5 SK |
914 | sockaddr_isequal(&f->source, addr)) |
915 | return f; | |
916 | ||
917 | return NULL; | |
918 | } | |
919 | ||
849a8357 SK |
920 | /* A server record is going away, remove references to it */ |
921 | void server_gone(struct daemon *daemon, struct server *server) | |
922 | { | |
923 | struct frec *f; | |
924 | ||
925 | for (f = frec_list; f; f = f->next) | |
926 | if (f->new_id != 0 && f->sentto == server) | |
927 | f->new_id = 0; | |
928 | ||
929 | if (daemon->last_server == server) | |
930 | daemon->last_server = NULL; | |
931 | ||
932 | if (daemon->srv_save == server) | |
933 | daemon->srv_save = NULL; | |
934 | } | |
9e4abcb5 SK |
935 | |
936 | /* return unique random ids between 1 and 65535 */ | |
937 | static unsigned short get_id(void) | |
938 | { | |
939 | unsigned short ret = 0; | |
940 | ||
941 | while (ret == 0) | |
942 | { | |
943 | ret = rand16(); | |
944 | ||
945 | /* scrap ids already in use */ | |
946 | if ((ret != 0) && lookup_frec(ret)) | |
947 | ret = 0; | |
948 | } | |
949 | ||
950 | return ret; | |
951 | } | |
952 | ||
953 | ||
954 | ||
955 | ||
956 |