]>
git.ipfire.org Git - people/ms/dnsmasq.git/blob - src/forward.c
1 /* dnsmasq is Copyright (c) 2000-2013 Simon Kelley
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, or
6 (at your option) version 3 dated 29 June, 2007.
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.
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/>.
19 static struct frec
*lookup_frec(unsigned short id
, unsigned int crc
);
20 static struct frec
*lookup_frec_by_sender(unsigned short id
,
21 union mysockaddr
*addr
,
23 static unsigned short get_id(unsigned int crc
);
24 static void free_frec(struct frec
*f
);
25 static struct randfd
*allocate_rfd(int family
);
27 /* Send a UDP packet with its source address set as "source"
28 unless nowild is true, when we just send it with the kernel default */
29 int send_from(int fd
, int nowild
, char *packet
, size_t len
,
30 union mysockaddr
*to
, struct all_addr
*source
,
36 struct cmsghdr align
; /* this ensures alignment */
37 #if defined(HAVE_LINUX_NETWORK)
38 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
39 #elif defined(IP_SENDSRCADDR)
40 char control
[CMSG_SPACE(sizeof(struct in_addr
))];
43 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
47 iov
[0].iov_base
= packet
;
50 msg
.msg_control
= NULL
;
51 msg
.msg_controllen
= 0;
54 msg
.msg_namelen
= sa_len(to
);
60 struct cmsghdr
*cmptr
;
61 msg
.msg_control
= &control_u
;
62 msg
.msg_controllen
= sizeof(control_u
);
63 cmptr
= CMSG_FIRSTHDR(&msg
);
65 if (to
->sa
.sa_family
== AF_INET
)
67 #if defined(HAVE_LINUX_NETWORK)
70 p
.ipi_spec_dst
= source
->addr
.addr4
;
71 memcpy(CMSG_DATA(cmptr
), &p
, sizeof(p
));
72 msg
.msg_controllen
= cmptr
->cmsg_len
= CMSG_LEN(sizeof(struct in_pktinfo
));
73 cmptr
->cmsg_level
= IPPROTO_IP
;
74 cmptr
->cmsg_type
= IP_PKTINFO
;
75 #elif defined(IP_SENDSRCADDR)
76 memcpy(CMSG_DATA(cmptr
), &(source
->addr
.addr4
), sizeof(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
;
86 p
.ipi6_ifindex
= iface
; /* Need iface for IPv6 to handle link-local addrs */
87 p
.ipi6_addr
= source
->addr
.addr6
;
88 memcpy(CMSG_DATA(cmptr
), &p
, sizeof(p
));
89 msg
.msg_controllen
= cmptr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
90 cmptr
->cmsg_type
= daemon
->v6pktinfo
;
91 cmptr
->cmsg_level
= IPPROTO_IPV6
;
94 (void)iface
; /* eliminate warning */
98 while (sendmsg(fd
, &msg
, 0) == -1)
103 /* If interface is still in DAD, EINVAL results - ignore that. */
107 my_syslog(LOG_ERR
, _("failed to send packet: %s"), strerror(errno
));
114 static unsigned int search_servers(time_t now
, struct all_addr
**addrpp
,
115 unsigned int qtype
, char *qdomain
, int *type
, char **domain
, int *norebind
)
118 /* If the query ends in the domain in one of our servers, set
119 domain to point to that name. We find the largest match to allow both
120 domain.org and sub.domain.org to exist. */
122 unsigned int namelen
= strlen(qdomain
);
123 unsigned int matchlen
= 0;
125 unsigned int flags
= 0;
127 for (serv
= daemon
->servers
; serv
; serv
=serv
->next
)
128 /* domain matches take priority over NODOTS matches */
129 if ((serv
->flags
& SERV_FOR_NODOTS
) && *type
!= SERV_HAS_DOMAIN
&& !strchr(qdomain
, '.') && namelen
!= 0)
131 unsigned int sflag
= serv
->addr
.sa
.sa_family
== AF_INET
? F_IPV4
: F_IPV6
;
132 *type
= SERV_FOR_NODOTS
;
133 if (serv
->flags
& SERV_NO_ADDR
)
135 else if (serv
->flags
& SERV_LITERAL_ADDRESS
)
140 if (serv
->addr
.sa
.sa_family
== AF_INET
)
141 *addrpp
= (struct all_addr
*)&serv
->addr
.in
.sin_addr
;
144 *addrpp
= (struct all_addr
*)&serv
->addr
.in6
.sin6_addr
;
147 else if (!flags
|| (flags
& F_NXDOMAIN
))
151 else if (serv
->flags
& SERV_HAS_DOMAIN
)
153 unsigned int domainlen
= strlen(serv
->domain
);
154 char *matchstart
= qdomain
+ namelen
- domainlen
;
155 if (namelen
>= domainlen
&&
156 hostname_isequal(matchstart
, serv
->domain
) &&
157 (domainlen
== 0 || namelen
== domainlen
|| *(matchstart
-1) == '.' ))
159 if (serv
->flags
& SERV_NO_REBIND
)
163 unsigned int sflag
= serv
->addr
.sa
.sa_family
== AF_INET
? F_IPV4
: F_IPV6
;
164 /* implement priority rules for --address and --server for same domain.
165 --address wins if the address is for the correct AF
166 --server wins otherwise. */
167 if (domainlen
!= 0 && domainlen
== matchlen
)
169 if ((serv
->flags
& SERV_LITERAL_ADDRESS
))
171 if (!(sflag
& qtype
) && flags
== 0)
176 if (flags
& (F_IPV4
| F_IPV6
))
181 if (domainlen
>= matchlen
)
183 *type
= serv
->flags
& (SERV_HAS_DOMAIN
| SERV_USE_RESOLV
| SERV_NO_REBIND
);
184 *domain
= serv
->domain
;
185 matchlen
= domainlen
;
186 if (serv
->flags
& SERV_NO_ADDR
)
188 else if (serv
->flags
& SERV_LITERAL_ADDRESS
)
193 if (serv
->addr
.sa
.sa_family
== AF_INET
)
194 *addrpp
= (struct all_addr
*)&serv
->addr
.in
.sin_addr
;
197 *addrpp
= (struct all_addr
*)&serv
->addr
.in6
.sin6_addr
;
200 else if (!flags
|| (flags
& F_NXDOMAIN
))
210 if (flags
== 0 && !(qtype
& F_QUERY
) &&
211 option_bool(OPT_NODOTS_LOCAL
) && !strchr(qdomain
, '.') && namelen
!= 0)
212 /* don't forward A or AAAA queries for simple names, except the empty name */
215 if (flags
== F_NXDOMAIN
&& check_for_local_domain(qdomain
, now
))
222 if (flags
== F_NXDOMAIN
|| flags
== F_NOERR
)
223 logflags
= F_NEG
| qtype
;
225 log_query(logflags
| flags
| F_CONFIG
| F_FORWARD
, qdomain
, *addrpp
, NULL
);
227 else if ((*type
) & SERV_USE_RESOLV
)
229 *type
= 0; /* use normal servers for this domain */
235 static int forward_query(int udpfd
, union mysockaddr
*udpaddr
,
236 struct all_addr
*dst_addr
, unsigned int dst_iface
,
237 struct dns_header
*header
, size_t plen
, time_t now
, struct frec
*forward
)
240 int type
= 0, norebind
= 0;
241 struct all_addr
*addrp
= NULL
;
242 unsigned int crc
= questions_crc(header
, plen
, daemon
->namebuff
);
243 unsigned int flags
= 0;
244 unsigned int gotname
= extract_request(header
, plen
, daemon
->namebuff
, NULL
);
245 struct server
*start
= NULL
;
247 /* RFC 4035: sect 4.6 para 2 */
248 header
->hb4
&= ~HB4_AD
;
250 /* may be no servers available. */
251 if (!daemon
->servers
)
253 else if (forward
|| (forward
= lookup_frec_by_sender(ntohs(header
->id
), udpaddr
, crc
)))
255 /* retry on existing query, send to all available servers */
256 domain
= forward
->sentto
->domain
;
257 forward
->sentto
->failed_queries
++;
258 if (!option_bool(OPT_ORDER
))
260 forward
->forwardall
= 1;
261 daemon
->last_server
= NULL
;
263 type
= forward
->sentto
->flags
& SERV_TYPE
;
264 if (!(start
= forward
->sentto
->next
))
265 start
= daemon
->servers
; /* at end of list, recycle */
266 header
->id
= htons(forward
->new_id
);
271 flags
= search_servers(now
, &addrp
, gotname
, daemon
->namebuff
, &type
, &domain
, &norebind
);
273 if (!flags
&& !(forward
= get_new_frec(now
, NULL
)))
274 /* table full - server failure. */
279 forward
->source
= *udpaddr
;
280 forward
->dest
= *dst_addr
;
281 forward
->iface
= dst_iface
;
282 forward
->orig_id
= ntohs(header
->id
);
283 forward
->new_id
= get_id(crc
);
286 forward
->forwardall
= 0;
289 forward
->flags
|= FREC_NOREBIND
;
290 if (header
->hb4
& HB4_CD
)
291 forward
->flags
|= FREC_CHECKING_DISABLED
;
293 header
->id
= htons(forward
->new_id
);
295 /* In strict_order mode, always try servers in the order
296 specified in resolv.conf, if a domain is given
297 always try all the available servers,
298 otherwise, use the one last known to work. */
302 if (option_bool(OPT_ORDER
))
303 start
= daemon
->servers
;
304 else if (!(start
= daemon
->last_server
) ||
305 daemon
->forwardcount
++ > FORWARD_TEST
||
306 difftime(now
, daemon
->forwardtime
) > FORWARD_TIME
)
308 start
= daemon
->servers
;
309 forward
->forwardall
= 1;
310 daemon
->forwardcount
= 0;
311 daemon
->forwardtime
= now
;
316 start
= daemon
->servers
;
317 if (!option_bool(OPT_ORDER
))
318 forward
->forwardall
= 1;
323 /* check for send errors here (no route to host)
324 if we fail to send to all nameservers, send back an error
325 packet straight away (helps modem users when offline) */
327 if (!flags
&& forward
)
329 struct server
*firstsentto
= start
;
332 if (option_bool(OPT_ADD_MAC
))
333 plen
= add_mac(header
, plen
, ((char *) header
) + PACKETSZ
, &forward
->source
);
335 if (option_bool(OPT_CLIENT_SUBNET
))
337 size_t new = add_source_addr(header
, plen
, ((char *) header
) + PACKETSZ
, &forward
->source
);
341 forward
->flags
|= FREC_HAS_SUBNET
;
347 /* only send to servers dealing with our domain.
348 domain may be NULL, in which case server->domain
349 must be NULL also. */
351 if (type
== (start
->flags
& SERV_TYPE
) &&
352 (type
!= SERV_HAS_DOMAIN
|| hostname_isequal(domain
, start
->domain
)) &&
353 !(start
->flags
& SERV_LITERAL_ADDRESS
))
357 /* find server socket to use, may need to get random one. */
363 if (start
->addr
.sa
.sa_family
== AF_INET6
)
365 if (!forward
->rfd6
&&
366 !(forward
->rfd6
= allocate_rfd(AF_INET6
)))
368 daemon
->rfd_save
= forward
->rfd6
;
369 fd
= forward
->rfd6
->fd
;
374 if (!forward
->rfd4
&&
375 !(forward
->rfd4
= allocate_rfd(AF_INET
)))
377 daemon
->rfd_save
= forward
->rfd4
;
378 fd
= forward
->rfd4
->fd
;
381 #ifdef HAVE_CONNTRACK
382 /* Copy connection mark of incoming query to outgoing connection. */
383 if (option_bool(OPT_CONNTRACK
))
386 if (get_incoming_mark(&forward
->source
, &forward
->dest
, 0, &mark
))
387 setsockopt(fd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
392 if (sendto(fd
, (char *)header
, plen
, 0,
394 sa_len(&start
->addr
)) == -1)
401 /* Keep info in case we want to re-send this packet */
402 daemon
->srv_save
= start
;
403 daemon
->packet_len
= plen
;
406 strcpy(daemon
->namebuff
, "query");
407 if (start
->addr
.sa
.sa_family
== AF_INET
)
408 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
409 (struct all_addr
*)&start
->addr
.in
.sin_addr
, NULL
);
412 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
413 (struct all_addr
*)&start
->addr
.in6
.sin6_addr
, NULL
);
417 forward
->sentto
= start
;
418 if (!forward
->forwardall
)
420 forward
->forwardall
++;
424 if (!(start
= start
->next
))
425 start
= daemon
->servers
;
427 if (start
== firstsentto
)
434 /* could not send on, prepare to return */
435 header
->id
= htons(forward
->orig_id
);
436 free_frec(forward
); /* cancel */
439 /* could not send on, return empty answer or address if known for whole domain */
442 plen
= setup_reply(header
, plen
, addrp
, flags
, daemon
->local_ttl
);
443 send_from(udpfd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
), (char *)header
, plen
, udpaddr
, dst_addr
, dst_iface
);
449 static size_t process_reply(struct dns_header
*header
, time_t now
, struct server
*server
, size_t n
, int check_rebind
,
450 int checking_disabled
, int check_subnet
, union mysockaddr
*query_source
)
452 unsigned char *pheader
, *sizep
;
454 int munged
= 0, is_sign
;
458 /* Similar algorithm to search_servers. */
459 struct ipsets
*ipset_pos
;
460 unsigned int namelen
= strlen(daemon
->namebuff
);
461 unsigned int matchlen
= 0;
462 for (ipset_pos
= daemon
->ipsets
; ipset_pos
; ipset_pos
= ipset_pos
->next
)
464 unsigned int domainlen
= strlen(ipset_pos
->domain
);
465 char *matchstart
= daemon
->namebuff
+ namelen
- domainlen
;
466 if (namelen
>= domainlen
&& hostname_isequal(matchstart
, ipset_pos
->domain
) &&
467 (domainlen
== 0 || namelen
== domainlen
|| *(matchstart
- 1) == '.' ) &&
468 domainlen
>= matchlen
) {
469 matchlen
= domainlen
;
470 sets
= ipset_pos
->sets
;
475 /* If upstream is advertising a larger UDP packet size
476 than we allow, trim it so that we don't get overlarge
477 requests for the client. We can't do this for signed packets. */
479 if ((pheader
= find_pseudoheader(header
, n
, &plen
, &sizep
, &is_sign
)))
483 unsigned short udpsz
;
484 unsigned char *psave
= sizep
;
486 GETSHORT(udpsz
, sizep
);
487 if (udpsz
> daemon
->edns_pktsz
)
488 PUTSHORT(daemon
->edns_pktsz
, psave
);
491 if (check_subnet
&& !check_source(header
, plen
, pheader
, query_source
))
493 my_syslog(LOG_WARNING
, _("discarding DNS reply: subnet option mismatch"));
499 /* RFC 4035 sect 4.6 para 3 */
500 if (!is_sign
&& !option_bool(OPT_DNSSEC_PROXY
))
501 header
->hb4
&= ~HB4_AD
;
503 if (OPCODE(header
) != QUERY
|| (RCODE(header
) != NOERROR
&& RCODE(header
) != NXDOMAIN
))
506 /* Complain loudly if the upstream server is non-recursive. */
507 if (!(header
->hb4
& HB4_RA
) && RCODE(header
) == NOERROR
&& ntohs(header
->ancount
) == 0 &&
508 server
&& !(server
->flags
& SERV_WARNED_RECURSIVE
))
510 prettyprint_addr(&server
->addr
, daemon
->namebuff
);
511 my_syslog(LOG_WARNING
, _("nameserver %s refused to do a recursive query"), daemon
->namebuff
);
512 if (!option_bool(OPT_LOG
))
513 server
->flags
|= SERV_WARNED_RECURSIVE
;
517 printf("validate\n");
518 dnssec_validate(header
, n
);
521 if (daemon
->bogus_addr
&& RCODE(header
) != NXDOMAIN
&&
522 check_for_bogus_wildcard(header
, n
, daemon
->namebuff
, daemon
->bogus_addr
, now
))
525 SET_RCODE(header
, NXDOMAIN
);
526 header
->hb3
&= ~HB3_AA
;
530 if (RCODE(header
) == NXDOMAIN
&&
531 extract_request(header
, n
, daemon
->namebuff
, NULL
) &&
532 check_for_local_domain(daemon
->namebuff
, now
))
534 /* if we forwarded a query for a locally known name (because it was for
535 an unknown type) and the answer is NXDOMAIN, convert that to NODATA,
536 since we know that the domain exists, even if upstream doesn't */
538 header
->hb3
|= HB3_AA
;
539 SET_RCODE(header
, NOERROR
);
542 if (extract_addresses(header
, n
, daemon
->namebuff
, now
, sets
, is_sign
, check_rebind
, checking_disabled
))
544 my_syslog(LOG_WARNING
, _("possible DNS-rebind attack detected: %s"), daemon
->namebuff
);
549 /* do this after extract_addresses. Ensure NODATA reply and remove
554 header
->ancount
= htons(0);
555 header
->nscount
= htons(0);
556 header
->arcount
= htons(0);
559 /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide
560 sections of the packet. Find the new length here and put back pseudoheader
561 if it was removed. */
562 return resize_packet(header
, n
, pheader
, plen
);
565 /* sets new last_server */
566 void reply_query(int fd
, int family
, time_t now
)
568 /* packet from peer server, extract data for cache, and send to
569 original requester */
570 struct dns_header
*header
;
571 union mysockaddr serveraddr
;
572 struct frec
*forward
;
573 socklen_t addrlen
= sizeof(serveraddr
);
574 ssize_t n
= recvfrom(fd
, daemon
->packet
, daemon
->edns_pktsz
, 0, &serveraddr
.sa
, &addrlen
);
576 struct server
*server
;
578 /* packet buffer overwritten */
579 daemon
->srv_save
= NULL
;
581 /* Determine the address of the server replying so that we can mark that as good */
582 serveraddr
.sa
.sa_family
= family
;
584 if (serveraddr
.sa
.sa_family
== AF_INET6
)
585 serveraddr
.in6
.sin6_flowinfo
= 0;
588 /* spoof check: answer must come from known server, */
589 for (server
= daemon
->servers
; server
; server
= server
->next
)
590 if (!(server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_NO_ADDR
)) &&
591 sockaddr_isequal(&server
->addr
, &serveraddr
))
594 header
= (struct dns_header
*)daemon
->packet
;
597 n
< (int)sizeof(struct dns_header
) || !(header
->hb3
& HB3_QR
) ||
598 !(forward
= lookup_frec(ntohs(header
->id
), questions_crc(header
, n
, daemon
->namebuff
))))
601 server
= forward
->sentto
;
603 if ((RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
) &&
604 !option_bool(OPT_ORDER
) &&
605 forward
->forwardall
== 0)
606 /* for broken servers, attempt to send to another one. */
608 unsigned char *pheader
;
612 /* recreate query from reply */
613 pheader
= find_pseudoheader(header
, (size_t)n
, &plen
, NULL
, &is_sign
);
616 header
->ancount
= htons(0);
617 header
->nscount
= htons(0);
618 header
->arcount
= htons(0);
619 if ((nn
= resize_packet(header
, (size_t)n
, pheader
, plen
)))
621 header
->hb3
&= ~(HB3_QR
| HB3_TC
);
622 forward_query(-1, NULL
, NULL
, 0, header
, nn
, now
, forward
);
628 if ((forward
->sentto
->flags
& SERV_TYPE
) == 0)
630 if (RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
)
634 struct server
*last_server
;
636 /* find good server by address if possible, otherwise assume the last one we sent to */
637 for (last_server
= daemon
->servers
; last_server
; last_server
= last_server
->next
)
638 if (!(last_server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_HAS_DOMAIN
| SERV_FOR_NODOTS
| SERV_NO_ADDR
)) &&
639 sockaddr_isequal(&last_server
->addr
, &serveraddr
))
641 server
= last_server
;
645 if (!option_bool(OPT_ALL_SERVERS
))
646 daemon
->last_server
= server
;
649 /* If the answer is an error, keep the forward record in place in case
650 we get a good reply from another server. Kill it when we've
651 had replies from all to avoid filling the forwarding table when
652 everything is broken */
653 if (forward
->forwardall
== 0 || --forward
->forwardall
== 1 ||
654 (RCODE(header
) != REFUSED
&& RCODE(header
) != SERVFAIL
))
656 int check_rebind
= !(forward
->flags
& FREC_NOREBIND
);
658 if (!option_bool(OPT_NO_REBIND
))
661 if ((nn
= process_reply(header
, now
, server
, (size_t)n
, check_rebind
, forward
->flags
& FREC_CHECKING_DISABLED
,
662 forward
->flags
& FREC_HAS_SUBNET
, &forward
->source
)))
664 header
->id
= htons(forward
->orig_id
);
665 header
->hb4
|= HB4_RA
; /* recursion if available */
666 send_from(forward
->fd
, option_bool(OPT_NOWILD
) || option_bool (OPT_CLEVERBIND
), daemon
->packet
, nn
,
667 &forward
->source
, &forward
->dest
, forward
->iface
);
669 free_frec(forward
); /* cancel */
674 void receive_query(struct listener
*listen
, time_t now
)
676 struct dns_header
*header
= (struct dns_header
*)daemon
->packet
;
677 union mysockaddr source_addr
;
679 struct all_addr dst_addr
;
680 struct in_addr netmask
, dst_addr_4
;
684 int local_auth
= 0, auth_dns
= 0;
687 struct cmsghdr
*cmptr
;
689 struct cmsghdr align
; /* this ensures alignment */
691 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
693 #if defined(HAVE_LINUX_NETWORK)
694 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
695 #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK)
696 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
697 CMSG_SPACE(sizeof(unsigned int))];
698 #elif defined(IP_RECVDSTADDR)
699 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
700 CMSG_SPACE(sizeof(struct sockaddr_dl
))];
704 /* packet buffer overwritten */
705 daemon
->srv_save
= NULL
;
707 dst_addr_4
.s_addr
= 0;
710 if (option_bool(OPT_NOWILD
) && listen
->iface
)
712 auth_dns
= listen
->iface
->dns_auth
;
714 if (listen
->family
== AF_INET
)
716 dst_addr_4
= listen
->iface
->addr
.in
.sin_addr
;
717 netmask
= listen
->iface
->netmask
;
721 iov
[0].iov_base
= daemon
->packet
;
722 iov
[0].iov_len
= daemon
->edns_pktsz
;
724 msg
.msg_control
= control_u
.control
;
725 msg
.msg_controllen
= sizeof(control_u
);
727 msg
.msg_name
= &source_addr
;
728 msg
.msg_namelen
= sizeof(source_addr
);
732 if ((n
= recvmsg(listen
->fd
, &msg
, 0)) == -1)
735 if (n
< (int)sizeof(struct dns_header
) ||
736 (msg
.msg_flags
& MSG_TRUNC
) ||
737 (header
->hb3
& HB3_QR
))
740 source_addr
.sa
.sa_family
= listen
->family
;
742 if (listen
->family
== AF_INET6
)
743 source_addr
.in6
.sin6_flowinfo
= 0;
746 if (!option_bool(OPT_NOWILD
))
750 if (msg
.msg_controllen
< sizeof(struct cmsghdr
))
753 #if defined(HAVE_LINUX_NETWORK)
754 if (listen
->family
== AF_INET
)
755 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
756 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_PKTINFO
)
760 struct in_pktinfo
*p
;
762 p
.c
= CMSG_DATA(cmptr
);
763 dst_addr_4
= dst_addr
.addr
.addr4
= p
.p
->ipi_spec_dst
;
764 if_index
= p
.p
->ipi_ifindex
;
766 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
767 if (listen
->family
== AF_INET
)
769 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
775 #ifndef HAVE_SOLARIS_NETWORK
776 struct sockaddr_dl
*s
;
779 p
.c
= CMSG_DATA(cmptr
);
780 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
781 dst_addr_4
= dst_addr
.addr
.addr4
= *(p
.a
);
782 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
783 #ifdef HAVE_SOLARIS_NETWORK
786 if_index
= p
.s
->sdl_index
;
793 if (listen
->family
== AF_INET6
)
795 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
796 if (cmptr
->cmsg_level
== IPPROTO_IPV6
&& cmptr
->cmsg_type
== daemon
->v6pktinfo
)
800 struct in6_pktinfo
*p
;
802 p
.c
= CMSG_DATA(cmptr
);
804 dst_addr
.addr
.addr6
= p
.p
->ipi6_addr
;
805 if_index
= p
.p
->ipi6_ifindex
;
810 /* enforce available interface configuration */
812 if (!indextoname(listen
->fd
, if_index
, ifr
.ifr_name
))
815 if (!iface_check(listen
->family
, &dst_addr
, ifr
.ifr_name
, &auth_dns
))
817 if (!option_bool(OPT_CLEVERBIND
))
818 enumerate_interfaces(0);
819 if (!loopback_exception(listen
->fd
, listen
->family
, &dst_addr
, ifr
.ifr_name
) &&
820 !label_exception(if_index
, listen
->family
, &dst_addr
))
824 if (listen
->family
== AF_INET
&& option_bool(OPT_LOCALISE
))
828 /* get the netmask of the interface whch has the address we were sent to.
829 This is no neccessarily the interface we arrived on. */
831 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
832 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
833 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
836 /* interface may be new */
837 if (!iface
&& !option_bool(OPT_CLEVERBIND
))
838 enumerate_interfaces(0);
840 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
841 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
842 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
845 /* If we failed, abandon localisation */
847 netmask
= iface
->netmask
;
849 dst_addr_4
.s_addr
= 0;
853 if (extract_request(header
, (size_t)n
, daemon
->namebuff
, &type
))
857 struct auth_zone
*zone
;
860 querystr(auth_dns
? "auth" : "query", types
, type
);
862 if (listen
->family
== AF_INET
)
863 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
864 (struct all_addr
*)&source_addr
.in
.sin_addr
, types
);
867 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
868 (struct all_addr
*)&source_addr
.in6
.sin6_addr
, types
);
872 /* find queries for zones we're authoritative for, and answer them directly */
874 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
875 if (in_zone(zone
, daemon
->namebuff
, NULL
))
887 m
= answer_auth(header
, ((char *) header
) + PACKETSZ
, (size_t)n
, now
, &source_addr
, local_auth
);
890 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
891 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
892 daemon
->auth_answer
++;
898 m
= answer_request(header
, ((char *) header
) + PACKETSZ
, (size_t)n
,
899 dst_addr_4
, netmask
, now
);
903 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
904 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
905 daemon
->local_answer
++;
907 else if (forward_query(listen
->fd
, &source_addr
, &dst_addr
, if_index
,
908 header
, (size_t)n
, now
, NULL
))
909 daemon
->queries_forwarded
++;
911 daemon
->local_answer
++;
915 /* The daemon forks before calling this: it should deal with one connection,
916 blocking as neccessary, and then return. Note, need to be a bit careful
917 about resources for debug mode, when the fork is suppressed: that's
918 done by the caller. */
919 unsigned char *tcp_request(int confd
, time_t now
,
920 union mysockaddr
*local_addr
, struct in_addr netmask
, int auth_dns
)
925 int checking_disabled
, check_subnet
;
927 unsigned short qtype
;
928 unsigned int gotname
;
929 unsigned char c1
, c2
;
930 /* Max TCP packet + slop + size */
931 unsigned char *packet
= whine_malloc(65536 + MAXDNAME
+ RRFIXEDSZ
+ sizeof(u16
));
932 unsigned char *payload
= &packet
[2];
933 /* largest field in header is 16-bits, so this is still sufficiently aligned */
934 struct dns_header
*header
= (struct dns_header
*)payload
;
935 u16
*length
= (u16
*)packet
;
936 struct server
*last_server
;
937 struct in_addr dst_addr_4
;
938 union mysockaddr peer_addr
;
939 socklen_t peer_len
= sizeof(union mysockaddr
);
941 if (getpeername(confd
, (struct sockaddr
*)&peer_addr
, &peer_len
) == -1)
947 !read_write(confd
, &c1
, 1, 1) || !read_write(confd
, &c2
, 1, 1) ||
948 !(size
= c1
<< 8 | c2
) ||
949 !read_write(confd
, payload
, size
, 1))
952 if (size
< (int)sizeof(struct dns_header
))
957 /* save state of "cd" flag in query */
958 checking_disabled
= header
->hb4
& HB4_CD
;
960 /* RFC 4035: sect 4.6 para 2 */
961 header
->hb4
&= ~HB4_AD
;
963 if ((gotname
= extract_request(header
, (unsigned int)size
, daemon
->namebuff
, &qtype
)))
967 struct auth_zone
*zone
;
969 querystr(auth_dns
? "auth" : "query", types
, qtype
);
971 if (peer_addr
.sa
.sa_family
== AF_INET
)
972 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
973 (struct all_addr
*)&peer_addr
.in
.sin_addr
, types
);
976 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
977 (struct all_addr
*)&peer_addr
.in6
.sin6_addr
, types
);
981 /* find queries for zones we're authoritative for, and answer them directly */
983 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
984 if (in_zone(zone
, daemon
->namebuff
, NULL
))
993 if (local_addr
->sa
.sa_family
== AF_INET
)
994 dst_addr_4
= local_addr
->in
.sin_addr
;
996 dst_addr_4
.s_addr
= 0;
1000 m
= answer_auth(header
, ((char *) header
) + 65536, (size_t)size
, now
, &peer_addr
, local_auth
);
1004 /* m > 0 if answered from cache */
1005 m
= answer_request(header
, ((char *) header
) + 65536, (size_t)size
,
1006 dst_addr_4
, netmask
, now
);
1008 /* Do this by steam now we're not in the select() loop */
1009 check_log_writer(NULL
);
1013 unsigned int flags
= 0;
1014 struct all_addr
*addrp
= NULL
;
1016 char *domain
= NULL
;
1018 if (option_bool(OPT_ADD_MAC
))
1019 size
= add_mac(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1021 if (option_bool(OPT_CLIENT_SUBNET
))
1023 size_t new = add_source_addr(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1032 flags
= search_servers(now
, &addrp
, gotname
, daemon
->namebuff
, &type
, &domain
, &norebind
);
1034 if (type
!= 0 || option_bool(OPT_ORDER
) || !daemon
->last_server
)
1035 last_server
= daemon
->servers
;
1037 last_server
= daemon
->last_server
;
1039 if (!flags
&& last_server
)
1041 struct server
*firstsendto
= NULL
;
1042 unsigned int crc
= questions_crc(header
, (unsigned int)size
, daemon
->namebuff
);
1044 /* Loop round available servers until we succeed in connecting to one.
1045 Note that this code subtley ensures that consecutive queries on this connection
1046 which can go to the same server, do so. */
1050 firstsendto
= last_server
;
1053 if (!(last_server
= last_server
->next
))
1054 last_server
= daemon
->servers
;
1056 if (last_server
== firstsendto
)
1060 /* server for wrong domain */
1061 if (type
!= (last_server
->flags
& SERV_TYPE
) ||
1062 (type
== SERV_HAS_DOMAIN
&& !hostname_isequal(domain
, last_server
->domain
)))
1065 if (last_server
->tcpfd
== -1)
1067 if ((last_server
->tcpfd
= socket(last_server
->addr
.sa
.sa_family
, SOCK_STREAM
, 0)) == -1)
1070 if ((!local_bind(last_server
->tcpfd
, &last_server
->source_addr
, last_server
->interface
, 1) ||
1071 connect(last_server
->tcpfd
, &last_server
->addr
.sa
, sa_len(&last_server
->addr
)) == -1))
1073 close(last_server
->tcpfd
);
1074 last_server
->tcpfd
= -1;
1078 #ifdef HAVE_CONNTRACK
1079 /* Copy connection mark of incoming query to outgoing connection. */
1080 if (option_bool(OPT_CONNTRACK
))
1083 struct all_addr local
;
1085 if (local_addr
->sa
.sa_family
== AF_INET6
)
1086 local
.addr
.addr6
= local_addr
->in6
.sin6_addr
;
1089 local
.addr
.addr4
= local_addr
->in
.sin_addr
;
1091 if (get_incoming_mark(&peer_addr
, &local
, 1, &mark
))
1092 setsockopt(last_server
->tcpfd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
1097 *length
= htons(size
);
1099 if (!read_write(last_server
->tcpfd
, packet
, size
+ sizeof(u16
), 0) ||
1100 !read_write(last_server
->tcpfd
, &c1
, 1, 1) ||
1101 !read_write(last_server
->tcpfd
, &c2
, 1, 1))
1103 close(last_server
->tcpfd
);
1104 last_server
->tcpfd
= -1;
1109 if (!read_write(last_server
->tcpfd
, payload
, m
, 1))
1113 strcpy(daemon
->namebuff
, "query");
1114 if (last_server
->addr
.sa
.sa_family
== AF_INET
)
1115 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1116 (struct all_addr
*)&last_server
->addr
.in
.sin_addr
, NULL
);
1119 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1120 (struct all_addr
*)&last_server
->addr
.in6
.sin6_addr
, NULL
);
1123 /* There's no point in updating the cache, since this process will exit and
1124 lose the information after a few queries. We make this call for the alias and
1125 bogus-nxdomain side-effects. */
1126 /* If the crc of the question section doesn't match the crc we sent, then
1127 someone might be attempting to insert bogus values into the cache by
1128 sending replies containing questions and bogus answers. */
1129 if (crc
== questions_crc(header
, (unsigned int)m
, daemon
->namebuff
))
1130 m
= process_reply(header
, now
, last_server
, (unsigned int)m
,
1131 option_bool(OPT_NO_REBIND
) && !norebind
, checking_disabled
,
1132 check_subnet
, &peer_addr
);
1138 /* In case of local answer or no connections made. */
1140 m
= setup_reply(header
, (unsigned int)size
, addrp
, flags
, daemon
->local_ttl
);
1144 check_log_writer(NULL
);
1148 if (m
== 0 || !read_write(confd
, packet
, m
+ sizeof(u16
), 0))
1153 static struct frec
*allocate_frec(time_t now
)
1157 if ((f
= (struct frec
*)whine_malloc(sizeof(struct frec
))))
1159 f
->next
= daemon
->frec_list
;
1167 daemon
->frec_list
= f
;
1173 static struct randfd
*allocate_rfd(int family
)
1175 static int finger
= 0;
1178 /* limit the number of sockets we have open to avoid starvation of
1179 (eg) TFTP. Once we have a reasonable number, randomness should be OK */
1181 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1182 if (daemon
->randomsocks
[i
].refcount
== 0)
1184 if ((daemon
->randomsocks
[i
].fd
= random_sock(family
)) == -1)
1187 daemon
->randomsocks
[i
].refcount
= 1;
1188 daemon
->randomsocks
[i
].family
= family
;
1189 return &daemon
->randomsocks
[i
];
1192 /* No free ones or cannot get new socket, grab an existing one */
1193 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1195 int j
= (i
+finger
) % RANDOM_SOCKS
;
1196 if (daemon
->randomsocks
[j
].refcount
!= 0 &&
1197 daemon
->randomsocks
[j
].family
== family
&&
1198 daemon
->randomsocks
[j
].refcount
!= 0xffff)
1201 daemon
->randomsocks
[j
].refcount
++;
1202 return &daemon
->randomsocks
[j
];
1206 return NULL
; /* doom */
1209 static void free_frec(struct frec
*f
)
1211 if (f
->rfd4
&& --(f
->rfd4
->refcount
) == 0)
1219 if (f
->rfd6
&& --(f
->rfd6
->refcount
) == 0)
1226 /* if wait==NULL return a free or older than TIMEOUT record.
1227 else return *wait zero if one available, or *wait is delay to
1228 when the oldest in-use record will expire. Impose an absolute
1229 limit of 4*TIMEOUT before we wipe things (for random sockets) */
1230 struct frec
*get_new_frec(time_t now
, int *wait
)
1232 struct frec
*f
, *oldest
, *target
;
1238 for (f
= daemon
->frec_list
, oldest
= NULL
, target
= NULL
, count
= 0; f
; f
= f
->next
, count
++)
1243 if (difftime(now
, f
->time
) >= 4*TIMEOUT
)
1249 if (!oldest
|| difftime(f
->time
, oldest
->time
) <= 0)
1259 /* can't find empty one, use oldest if there is one
1260 and it's older than timeout */
1261 if (oldest
&& ((int)difftime(now
, oldest
->time
)) >= TIMEOUT
)
1263 /* keep stuff for twice timeout if we can by allocating a new
1265 if (difftime(now
, oldest
->time
) < 2*TIMEOUT
&&
1266 count
<= daemon
->ftabsize
&&
1267 (f
= allocate_frec(now
)))
1278 /* none available, calculate time 'till oldest record expires */
1279 if (count
> daemon
->ftabsize
)
1281 static time_t last_log
= 0;
1284 *wait
= oldest
->time
+ (time_t)TIMEOUT
- now
;
1286 if ((int)difftime(now
, last_log
) > 5)
1289 my_syslog(LOG_WARNING
, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon
->ftabsize
);
1295 if (!(f
= allocate_frec(now
)) && wait
)
1296 /* wait one second on malloc failure */
1299 return f
; /* OK if malloc fails and this is NULL */
1302 /* crc is all-ones if not known. */
1303 static struct frec
*lookup_frec(unsigned short id
, unsigned int crc
)
1307 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1308 if (f
->sentto
&& f
->new_id
== id
&&
1309 (f
->crc
== crc
|| crc
== 0xffffffff))
1315 static struct frec
*lookup_frec_by_sender(unsigned short id
,
1316 union mysockaddr
*addr
,
1321 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1325 sockaddr_isequal(&f
->source
, addr
))
1331 /* A server record is going away, remove references to it */
1332 void server_gone(struct server
*server
)
1336 for (f
= daemon
->frec_list
; f
; f
= f
->next
)
1337 if (f
->sentto
&& f
->sentto
== server
)
1340 if (daemon
->last_server
== server
)
1341 daemon
->last_server
= NULL
;
1343 if (daemon
->srv_save
== server
)
1344 daemon
->srv_save
= NULL
;
1347 /* return unique random ids. */
1348 static unsigned short get_id(unsigned int crc
)
1350 unsigned short ret
= 0;
1354 while (lookup_frec(ret
, crc
));