]>
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
))
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
;
516 if (daemon
->bogus_addr
&& RCODE(header
) != NXDOMAIN
&&
517 check_for_bogus_wildcard(header
, n
, daemon
->namebuff
, daemon
->bogus_addr
, now
))
520 SET_RCODE(header
, NXDOMAIN
);
521 header
->hb3
&= ~HB3_AA
;
525 if (RCODE(header
) == NXDOMAIN
&&
526 extract_request(header
, n
, daemon
->namebuff
, NULL
) &&
527 check_for_local_domain(daemon
->namebuff
, now
))
529 /* if we forwarded a query for a locally known name (because it was for
530 an unknown type) and the answer is NXDOMAIN, convert that to NODATA,
531 since we know that the domain exists, even if upstream doesn't */
533 header
->hb3
|= HB3_AA
;
534 SET_RCODE(header
, NOERROR
);
537 if (extract_addresses(header
, n
, daemon
->namebuff
, now
, sets
, is_sign
, check_rebind
, checking_disabled
))
539 my_syslog(LOG_WARNING
, _("possible DNS-rebind attack detected: %s"), daemon
->namebuff
);
544 /* do this after extract_addresses. Ensure NODATA reply and remove
549 header
->ancount
= htons(0);
550 header
->nscount
= htons(0);
551 header
->arcount
= htons(0);
554 /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide
555 sections of the packet. Find the new length here and put back pseudoheader
556 if it was removed. */
557 return resize_packet(header
, n
, pheader
, plen
);
560 /* sets new last_server */
561 void reply_query(int fd
, int family
, time_t now
)
563 /* packet from peer server, extract data for cache, and send to
564 original requester */
565 struct dns_header
*header
;
566 union mysockaddr serveraddr
;
567 struct frec
*forward
;
568 socklen_t addrlen
= sizeof(serveraddr
);
569 ssize_t n
= recvfrom(fd
, daemon
->packet
, daemon
->edns_pktsz
, 0, &serveraddr
.sa
, &addrlen
);
571 struct server
*server
;
573 /* packet buffer overwritten */
574 daemon
->srv_save
= NULL
;
576 /* Determine the address of the server replying so that we can mark that as good */
577 serveraddr
.sa
.sa_family
= family
;
579 if (serveraddr
.sa
.sa_family
== AF_INET6
)
580 serveraddr
.in6
.sin6_flowinfo
= 0;
583 /* spoof check: answer must come from known server, */
584 for (server
= daemon
->servers
; server
; server
= server
->next
)
585 if (!(server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_NO_ADDR
)) &&
586 sockaddr_isequal(&server
->addr
, &serveraddr
))
589 header
= (struct dns_header
*)daemon
->packet
;
592 n
< (int)sizeof(struct dns_header
) || !(header
->hb3
& HB3_QR
) ||
593 !(forward
= lookup_frec(ntohs(header
->id
), questions_crc(header
, n
, daemon
->namebuff
))))
596 server
= forward
->sentto
;
598 if ((RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
) &&
599 !option_bool(OPT_ORDER
) &&
600 forward
->forwardall
== 0)
601 /* for broken servers, attempt to send to another one. */
603 unsigned char *pheader
;
607 /* recreate query from reply */
608 pheader
= find_pseudoheader(header
, (size_t)n
, &plen
, NULL
, &is_sign
);
611 header
->ancount
= htons(0);
612 header
->nscount
= htons(0);
613 header
->arcount
= htons(0);
614 if ((nn
= resize_packet(header
, (size_t)n
, pheader
, plen
)))
616 header
->hb3
&= ~(HB3_QR
| HB3_TC
);
617 forward_query(-1, NULL
, NULL
, 0, header
, nn
, now
, forward
);
623 if ((forward
->sentto
->flags
& SERV_TYPE
) == 0)
625 if (RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
)
629 struct server
*last_server
;
631 /* find good server by address if possible, otherwise assume the last one we sent to */
632 for (last_server
= daemon
->servers
; last_server
; last_server
= last_server
->next
)
633 if (!(last_server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_HAS_DOMAIN
| SERV_FOR_NODOTS
| SERV_NO_ADDR
)) &&
634 sockaddr_isequal(&last_server
->addr
, &serveraddr
))
636 server
= last_server
;
640 if (!option_bool(OPT_ALL_SERVERS
))
641 daemon
->last_server
= server
;
644 /* If the answer is an error, keep the forward record in place in case
645 we get a good reply from another server. Kill it when we've
646 had replies from all to avoid filling the forwarding table when
647 everything is broken */
648 if (forward
->forwardall
== 0 || --forward
->forwardall
== 1 ||
649 (RCODE(header
) != REFUSED
&& RCODE(header
) != SERVFAIL
))
651 int check_rebind
= !(forward
->flags
& FREC_NOREBIND
);
653 if (!option_bool(OPT_NO_REBIND
))
656 if ((nn
= process_reply(header
, now
, server
, (size_t)n
, check_rebind
, forward
->flags
& FREC_CHECKING_DISABLED
,
657 forward
->flags
& FREC_HAS_SUBNET
, &forward
->source
)))
659 header
->id
= htons(forward
->orig_id
);
660 header
->hb4
|= HB4_RA
; /* recursion if available */
661 send_from(forward
->fd
, option_bool(OPT_NOWILD
) || option_bool (OPT_CLEVERBIND
), daemon
->packet
, nn
,
662 &forward
->source
, &forward
->dest
, forward
->iface
);
664 free_frec(forward
); /* cancel */
669 void receive_query(struct listener
*listen
, time_t now
)
671 struct dns_header
*header
= (struct dns_header
*)daemon
->packet
;
672 union mysockaddr source_addr
;
674 struct all_addr dst_addr
;
675 struct in_addr netmask
, dst_addr_4
;
682 struct cmsghdr
*cmptr
;
684 struct cmsghdr align
; /* this ensures alignment */
686 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
688 #if defined(HAVE_LINUX_NETWORK)
689 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
690 #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK)
691 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
692 CMSG_SPACE(sizeof(unsigned int))];
693 #elif defined(IP_RECVDSTADDR)
694 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
695 CMSG_SPACE(sizeof(struct sockaddr_dl
))];
699 /* packet buffer overwritten */
700 daemon
->srv_save
= NULL
;
702 dst_addr_4
.s_addr
= 0;
705 if (option_bool(OPT_NOWILD
) && listen
->iface
)
707 auth_dns
= listen
->iface
->dns_auth
;
709 if (listen
->family
== AF_INET
)
711 dst_addr_4
= listen
->iface
->addr
.in
.sin_addr
;
712 netmask
= listen
->iface
->netmask
;
716 iov
[0].iov_base
= daemon
->packet
;
717 iov
[0].iov_len
= daemon
->edns_pktsz
;
719 msg
.msg_control
= control_u
.control
;
720 msg
.msg_controllen
= sizeof(control_u
);
722 msg
.msg_name
= &source_addr
;
723 msg
.msg_namelen
= sizeof(source_addr
);
727 if ((n
= recvmsg(listen
->fd
, &msg
, 0)) == -1)
730 if (n
< (int)sizeof(struct dns_header
) ||
731 (msg
.msg_flags
& MSG_TRUNC
) ||
732 (header
->hb3
& HB3_QR
))
735 source_addr
.sa
.sa_family
= listen
->family
;
737 if (listen
->family
== AF_INET6
)
738 source_addr
.in6
.sin6_flowinfo
= 0;
741 if (!option_bool(OPT_NOWILD
))
745 if (msg
.msg_controllen
< sizeof(struct cmsghdr
))
748 #if defined(HAVE_LINUX_NETWORK)
749 if (listen
->family
== AF_INET
)
750 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
751 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_PKTINFO
)
755 struct in_pktinfo
*p
;
757 p
.c
= CMSG_DATA(cmptr
);
758 dst_addr_4
= dst_addr
.addr
.addr4
= p
.p
->ipi_spec_dst
;
759 if_index
= p
.p
->ipi_ifindex
;
761 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
762 if (listen
->family
== AF_INET
)
764 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
770 #ifndef HAVE_SOLARIS_NETWORK
771 struct sockaddr_dl
*s
;
774 p
.c
= CMSG_DATA(cmptr
);
775 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
776 dst_addr_4
= dst_addr
.addr
.addr4
= *(p
.a
);
777 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
778 #ifdef HAVE_SOLARIS_NETWORK
781 if_index
= p
.s
->sdl_index
;
788 if (listen
->family
== AF_INET6
)
790 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
791 if (cmptr
->cmsg_level
== IPPROTO_IPV6
&& cmptr
->cmsg_type
== daemon
->v6pktinfo
)
795 struct in6_pktinfo
*p
;
797 p
.c
= CMSG_DATA(cmptr
);
799 dst_addr
.addr
.addr6
= p
.p
->ipi6_addr
;
800 if_index
= p
.p
->ipi6_ifindex
;
805 /* enforce available interface configuration */
807 if (!indextoname(listen
->fd
, if_index
, ifr
.ifr_name
))
810 if (!iface_check(listen
->family
, &dst_addr
, ifr
.ifr_name
, &auth_dns
))
812 if (!option_bool(OPT_CLEVERBIND
))
813 enumerate_interfaces(0);
814 if (!loopback_exception(listen
->fd
, listen
->family
, &dst_addr
, ifr
.ifr_name
) &&
815 !label_exception(if_index
, listen
->family
, &dst_addr
))
819 if (listen
->family
== AF_INET
&& option_bool(OPT_LOCALISE
))
823 /* get the netmask of the interface whch has the address we were sent to.
824 This is no neccessarily the interface we arrived on. */
826 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
827 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
828 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
831 /* interface may be new */
832 if (!iface
&& !option_bool(OPT_CLEVERBIND
))
833 enumerate_interfaces(0);
835 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
836 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
837 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
840 /* If we failed, abandon localisation */
842 netmask
= iface
->netmask
;
844 dst_addr_4
.s_addr
= 0;
848 if (extract_request(header
, (size_t)n
, daemon
->namebuff
, &type
))
852 querystr(auth_dns
? "auth" : "query", types
, type
);
854 if (listen
->family
== AF_INET
)
855 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
856 (struct all_addr
*)&source_addr
.in
.sin_addr
, types
);
859 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
860 (struct all_addr
*)&source_addr
.in6
.sin6_addr
, types
);
867 m
= answer_auth(header
, ((char *) header
) + PACKETSZ
, (size_t)n
, now
, &source_addr
);
869 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
870 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
875 m
= answer_request(header
, ((char *) header
) + PACKETSZ
, (size_t)n
,
876 dst_addr_4
, netmask
, now
);
880 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
881 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
882 daemon
->local_answer
++;
884 else if (forward_query(listen
->fd
, &source_addr
, &dst_addr
, if_index
,
885 header
, (size_t)n
, now
, NULL
))
886 daemon
->queries_forwarded
++;
888 daemon
->local_answer
++;
892 /* The daemon forks before calling this: it should deal with one connection,
893 blocking as neccessary, and then return. Note, need to be a bit careful
894 about resources for debug mode, when the fork is suppressed: that's
895 done by the caller. */
896 unsigned char *tcp_request(int confd
, time_t now
,
897 union mysockaddr
*local_addr
, struct in_addr netmask
, int auth_dns
)
901 int checking_disabled
, check_subnet
;
903 unsigned short qtype
;
904 unsigned int gotname
;
905 unsigned char c1
, c2
;
906 /* Max TCP packet + slop + size */
907 unsigned char *packet
= whine_malloc(65536 + MAXDNAME
+ RRFIXEDSZ
+ sizeof(u16
));
908 unsigned char *payload
= &packet
[2];
909 /* largest field in header is 16-bits, so this is still sufficiently aligned */
910 struct dns_header
*header
= (struct dns_header
*)payload
;
911 u16
*length
= (u16
*)packet
;
912 struct server
*last_server
;
913 struct in_addr dst_addr_4
;
914 union mysockaddr peer_addr
;
915 socklen_t peer_len
= sizeof(union mysockaddr
);
917 if (getpeername(confd
, (struct sockaddr
*)&peer_addr
, &peer_len
) == -1)
923 !read_write(confd
, &c1
, 1, 1) || !read_write(confd
, &c2
, 1, 1) ||
924 !(size
= c1
<< 8 | c2
) ||
925 !read_write(confd
, payload
, size
, 1))
928 if (size
< (int)sizeof(struct dns_header
))
933 /* save state of "cd" flag in query */
934 checking_disabled
= header
->hb4
& HB4_CD
;
936 /* RFC 4035: sect 4.6 para 2 */
937 header
->hb4
&= ~HB4_AD
;
939 if ((gotname
= extract_request(header
, (unsigned int)size
, daemon
->namebuff
, &qtype
)))
943 querystr(auth_dns
? "auth" : "query", types
, qtype
);
945 if (peer_addr
.sa
.sa_family
== AF_INET
)
946 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
947 (struct all_addr
*)&peer_addr
.in
.sin_addr
, types
);
950 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
951 (struct all_addr
*)&peer_addr
.in6
.sin6_addr
, types
);
955 if (local_addr
->sa
.sa_family
== AF_INET
)
956 dst_addr_4
= local_addr
->in
.sin_addr
;
958 dst_addr_4
.s_addr
= 0;
962 m
= answer_auth(header
, ((char *) header
) + 65536, (size_t)size
, now
, &peer_addr
);
966 /* m > 0 if answered from cache */
967 m
= answer_request(header
, ((char *) header
) + 65536, (size_t)size
,
968 dst_addr_4
, netmask
, now
);
970 /* Do this by steam now we're not in the select() loop */
971 check_log_writer(NULL
);
975 unsigned int flags
= 0;
976 struct all_addr
*addrp
= NULL
;
980 if (option_bool(OPT_ADD_MAC
))
981 size
= add_mac(header
, size
, ((char *) header
) + 65536, &peer_addr
);
983 if (option_bool(OPT_CLIENT_SUBNET
))
985 size_t new = add_source_addr(header
, size
, ((char *) header
) + 65536, &peer_addr
);
994 flags
= search_servers(now
, &addrp
, gotname
, daemon
->namebuff
, &type
, &domain
, &norebind
);
996 if (type
!= 0 || option_bool(OPT_ORDER
) || !daemon
->last_server
)
997 last_server
= daemon
->servers
;
999 last_server
= daemon
->last_server
;
1001 if (!flags
&& last_server
)
1003 struct server
*firstsendto
= NULL
;
1004 unsigned int crc
= questions_crc(header
, (unsigned int)size
, daemon
->namebuff
);
1006 /* Loop round available servers until we succeed in connecting to one.
1007 Note that this code subtley ensures that consecutive queries on this connection
1008 which can go to the same server, do so. */
1012 firstsendto
= last_server
;
1015 if (!(last_server
= last_server
->next
))
1016 last_server
= daemon
->servers
;
1018 if (last_server
== firstsendto
)
1022 /* server for wrong domain */
1023 if (type
!= (last_server
->flags
& SERV_TYPE
) ||
1024 (type
== SERV_HAS_DOMAIN
&& !hostname_isequal(domain
, last_server
->domain
)))
1027 if (last_server
->tcpfd
== -1)
1029 if ((last_server
->tcpfd
= socket(last_server
->addr
.sa
.sa_family
, SOCK_STREAM
, 0)) == -1)
1032 if ((!local_bind(last_server
->tcpfd
, &last_server
->source_addr
, last_server
->interface
, 1) ||
1033 connect(last_server
->tcpfd
, &last_server
->addr
.sa
, sa_len(&last_server
->addr
)) == -1))
1035 close(last_server
->tcpfd
);
1036 last_server
->tcpfd
= -1;
1040 #ifdef HAVE_CONNTRACK
1041 /* Copy connection mark of incoming query to outgoing connection. */
1042 if (option_bool(OPT_CONNTRACK
))
1045 struct all_addr local
;
1047 if (local_addr
->sa
.sa_family
== AF_INET6
)
1048 local
.addr
.addr6
= local_addr
->in6
.sin6_addr
;
1051 local
.addr
.addr4
= local_addr
->in
.sin_addr
;
1053 if (get_incoming_mark(&peer_addr
, &local
, 1, &mark
))
1054 setsockopt(last_server
->tcpfd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
1059 *length
= htons(size
);
1061 if (!read_write(last_server
->tcpfd
, packet
, size
+ sizeof(u16
), 0) ||
1062 !read_write(last_server
->tcpfd
, &c1
, 1, 1) ||
1063 !read_write(last_server
->tcpfd
, &c2
, 1, 1))
1065 close(last_server
->tcpfd
);
1066 last_server
->tcpfd
= -1;
1071 if (!read_write(last_server
->tcpfd
, payload
, m
, 1))
1075 strcpy(daemon
->namebuff
, "query");
1076 if (last_server
->addr
.sa
.sa_family
== AF_INET
)
1077 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1078 (struct all_addr
*)&last_server
->addr
.in
.sin_addr
, NULL
);
1081 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1082 (struct all_addr
*)&last_server
->addr
.in6
.sin6_addr
, NULL
);
1085 /* There's no point in updating the cache, since this process will exit and
1086 lose the information after a few queries. We make this call for the alias and
1087 bogus-nxdomain side-effects. */
1088 /* If the crc of the question section doesn't match the crc we sent, then
1089 someone might be attempting to insert bogus values into the cache by
1090 sending replies containing questions and bogus answers. */
1091 if (crc
== questions_crc(header
, (unsigned int)m
, daemon
->namebuff
))
1092 m
= process_reply(header
, now
, last_server
, (unsigned int)m
,
1093 option_bool(OPT_NO_REBIND
) && !norebind
, checking_disabled
,
1094 check_subnet
, &peer_addr
);
1100 /* In case of local answer or no connections made. */
1102 m
= setup_reply(header
, (unsigned int)size
, addrp
, flags
, daemon
->local_ttl
);
1106 check_log_writer(NULL
);
1110 if (m
== 0 || !read_write(confd
, packet
, m
+ sizeof(u16
), 0))
1115 static struct frec
*allocate_frec(time_t now
)
1119 if ((f
= (struct frec
*)whine_malloc(sizeof(struct frec
))))
1121 f
->next
= daemon
->frec_list
;
1129 daemon
->frec_list
= f
;
1135 static struct randfd
*allocate_rfd(int family
)
1137 static int finger
= 0;
1140 /* limit the number of sockets we have open to avoid starvation of
1141 (eg) TFTP. Once we have a reasonable number, randomness should be OK */
1143 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1144 if (daemon
->randomsocks
[i
].refcount
== 0)
1146 if ((daemon
->randomsocks
[i
].fd
= random_sock(family
)) == -1)
1149 daemon
->randomsocks
[i
].refcount
= 1;
1150 daemon
->randomsocks
[i
].family
= family
;
1151 return &daemon
->randomsocks
[i
];
1154 /* No free ones or cannot get new socket, grab an existing one */
1155 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1157 int j
= (i
+finger
) % RANDOM_SOCKS
;
1158 if (daemon
->randomsocks
[j
].refcount
!= 0 &&
1159 daemon
->randomsocks
[j
].family
== family
&&
1160 daemon
->randomsocks
[j
].refcount
!= 0xffff)
1163 daemon
->randomsocks
[j
].refcount
++;
1164 return &daemon
->randomsocks
[j
];
1168 return NULL
; /* doom */
1171 static void free_frec(struct frec
*f
)
1173 if (f
->rfd4
&& --(f
->rfd4
->refcount
) == 0)
1181 if (f
->rfd6
&& --(f
->rfd6
->refcount
) == 0)
1188 /* if wait==NULL return a free or older than TIMEOUT record.
1189 else return *wait zero if one available, or *wait is delay to
1190 when the oldest in-use record will expire. Impose an absolute
1191 limit of 4*TIMEOUT before we wipe things (for random sockets) */
1192 struct frec
*get_new_frec(time_t now
, int *wait
)
1194 struct frec
*f
, *oldest
, *target
;
1200 for (f
= daemon
->frec_list
, oldest
= NULL
, target
= NULL
, count
= 0; f
; f
= f
->next
, count
++)
1205 if (difftime(now
, f
->time
) >= 4*TIMEOUT
)
1211 if (!oldest
|| difftime(f
->time
, oldest
->time
) <= 0)
1221 /* can't find empty one, use oldest if there is one
1222 and it's older than timeout */
1223 if (oldest
&& ((int)difftime(now
, oldest
->time
)) >= TIMEOUT
)
1225 /* keep stuff for twice timeout if we can by allocating a new
1227 if (difftime(now
, oldest
->time
) < 2*TIMEOUT
&&
1228 count
<= daemon
->ftabsize
&&
1229 (f
= allocate_frec(now
)))
1240 /* none available, calculate time 'till oldest record expires */
1241 if (count
> daemon
->ftabsize
)
1243 static time_t last_log
= 0;
1246 *wait
= oldest
->time
+ (time_t)TIMEOUT
- now
;
1248 if ((int)difftime(now
, last_log
) > 5)
1251 my_syslog(LOG_WARNING
, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon
->ftabsize
);
1257 if (!(f
= allocate_frec(now
)) && wait
)
1258 /* wait one second on malloc failure */
1261 return f
; /* OK if malloc fails and this is NULL */
1264 /* crc is all-ones if not known. */
1265 static struct frec
*lookup_frec(unsigned short id
, unsigned int crc
)
1269 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1270 if (f
->sentto
&& f
->new_id
== id
&&
1271 (f
->crc
== crc
|| crc
== 0xffffffff))
1277 static struct frec
*lookup_frec_by_sender(unsigned short id
,
1278 union mysockaddr
*addr
,
1283 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1287 sockaddr_isequal(&f
->source
, addr
))
1293 /* A server record is going away, remove references to it */
1294 void server_gone(struct server
*server
)
1298 for (f
= daemon
->frec_list
; f
; f
= f
->next
)
1299 if (f
->sentto
&& f
->sentto
== server
)
1302 if (daemon
->last_server
== server
)
1303 daemon
->last_server
= NULL
;
1305 if (daemon
->srv_save
== server
)
1306 daemon
->srv_save
= NULL
;
1309 /* return unique random ids. */
1310 static unsigned short get_id(unsigned int crc
)
1312 unsigned short ret
= 0;
1316 while (lookup_frec(ret
, crc
));