]>
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
, 0)))
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
;
346 if (option_bool(OPT_DNSSEC_VALID
))
347 plen
= add_do_bit(header
, plen
, ((char *) header
) + PACKETSZ
);
352 /* only send to servers dealing with our domain.
353 domain may be NULL, in which case server->domain
354 must be NULL also. */
356 if (type
== (start
->flags
& SERV_TYPE
) &&
357 (type
!= SERV_HAS_DOMAIN
|| hostname_isequal(domain
, start
->domain
)) &&
358 !(start
->flags
& SERV_LITERAL_ADDRESS
))
362 /* find server socket to use, may need to get random one. */
368 if (start
->addr
.sa
.sa_family
== AF_INET6
)
370 if (!forward
->rfd6
&&
371 !(forward
->rfd6
= allocate_rfd(AF_INET6
)))
373 daemon
->rfd_save
= forward
->rfd6
;
374 fd
= forward
->rfd6
->fd
;
379 if (!forward
->rfd4
&&
380 !(forward
->rfd4
= allocate_rfd(AF_INET
)))
382 daemon
->rfd_save
= forward
->rfd4
;
383 fd
= forward
->rfd4
->fd
;
386 #ifdef HAVE_CONNTRACK
387 /* Copy connection mark of incoming query to outgoing connection. */
388 if (option_bool(OPT_CONNTRACK
))
391 if (get_incoming_mark(&forward
->source
, &forward
->dest
, 0, &mark
))
392 setsockopt(fd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
397 if (sendto(fd
, (char *)header
, plen
, 0,
399 sa_len(&start
->addr
)) == -1)
406 /* Keep info in case we want to re-send this packet */
407 daemon
->srv_save
= start
;
408 daemon
->packet_len
= plen
;
411 strcpy(daemon
->namebuff
, "query");
412 if (start
->addr
.sa
.sa_family
== AF_INET
)
413 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
414 (struct all_addr
*)&start
->addr
.in
.sin_addr
, NULL
);
417 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
418 (struct all_addr
*)&start
->addr
.in6
.sin6_addr
, NULL
);
422 forward
->sentto
= start
;
423 if (!forward
->forwardall
)
425 forward
->forwardall
++;
429 if (!(start
= start
->next
))
430 start
= daemon
->servers
;
432 if (start
== firstsentto
)
439 /* could not send on, prepare to return */
440 header
->id
= htons(forward
->orig_id
);
441 free_frec(forward
); /* cancel */
444 /* could not send on, return empty answer or address if known for whole domain */
447 plen
= setup_reply(header
, plen
, addrp
, flags
, daemon
->local_ttl
);
448 send_from(udpfd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
), (char *)header
, plen
, udpaddr
, dst_addr
, dst_iface
);
454 static size_t process_reply(struct dns_header
*header
, time_t now
, struct server
*server
, size_t n
, int check_rebind
,
455 int no_cache
, int cache_secure
, int check_subnet
, union mysockaddr
*query_source
)
457 unsigned char *pheader
, *sizep
;
459 int munged
= 0, is_sign
;
464 /* Similar algorithm to search_servers. */
465 struct ipsets
*ipset_pos
;
466 unsigned int namelen
= strlen(daemon
->namebuff
);
467 unsigned int matchlen
= 0;
468 for (ipset_pos
= daemon
->ipsets
; ipset_pos
; ipset_pos
= ipset_pos
->next
)
470 unsigned int domainlen
= strlen(ipset_pos
->domain
);
471 char *matchstart
= daemon
->namebuff
+ namelen
- domainlen
;
472 if (namelen
>= domainlen
&& hostname_isequal(matchstart
, ipset_pos
->domain
) &&
473 (domainlen
== 0 || namelen
== domainlen
|| *(matchstart
- 1) == '.' ) &&
474 domainlen
>= matchlen
) {
475 matchlen
= domainlen
;
476 sets
= ipset_pos
->sets
;
481 /* If upstream is advertising a larger UDP packet size
482 than we allow, trim it so that we don't get overlarge
483 requests for the client. We can't do this for signed packets. */
485 if ((pheader
= find_pseudoheader(header
, n
, &plen
, &sizep
, &is_sign
)))
489 unsigned short udpsz
;
490 unsigned char *psave
= sizep
;
492 GETSHORT(udpsz
, sizep
);
493 if (udpsz
> daemon
->edns_pktsz
)
494 PUTSHORT(daemon
->edns_pktsz
, psave
);
497 if (check_subnet
&& !check_source(header
, plen
, pheader
, query_source
))
499 my_syslog(LOG_WARNING
, _("discarding DNS reply: subnet option mismatch"));
504 /* RFC 4035 sect 4.6 para 3 */
505 if (!is_sign
&& !option_bool(OPT_DNSSEC_PROXY
))
509 if (option_bool(OPT_DNSSEC_VALID
))
510 squash_ad
= no_cache
;
513 header
->hb4
|= HB4_AD
;
517 header
->hb4
&= ~HB4_AD
;
519 if (OPCODE(header
) != QUERY
|| (RCODE(header
) != NOERROR
&& RCODE(header
) != NXDOMAIN
))
522 /* Complain loudly if the upstream server is non-recursive. */
523 if (!(header
->hb4
& HB4_RA
) && RCODE(header
) == NOERROR
&& ntohs(header
->ancount
) == 0 &&
524 server
&& !(server
->flags
& SERV_WARNED_RECURSIVE
))
526 prettyprint_addr(&server
->addr
, daemon
->namebuff
);
527 my_syslog(LOG_WARNING
, _("nameserver %s refused to do a recursive query"), daemon
->namebuff
);
528 if (!option_bool(OPT_LOG
))
529 server
->flags
|= SERV_WARNED_RECURSIVE
;
532 if (daemon
->bogus_addr
&& RCODE(header
) != NXDOMAIN
&&
533 check_for_bogus_wildcard(header
, n
, daemon
->namebuff
, daemon
->bogus_addr
, now
))
536 SET_RCODE(header
, NXDOMAIN
);
537 header
->hb3
&= ~HB3_AA
;
541 if (RCODE(header
) == NXDOMAIN
&&
542 extract_request(header
, n
, daemon
->namebuff
, NULL
) &&
543 check_for_local_domain(daemon
->namebuff
, now
))
545 /* if we forwarded a query for a locally known name (because it was for
546 an unknown type) and the answer is NXDOMAIN, convert that to NODATA,
547 since we know that the domain exists, even if upstream doesn't */
549 header
->hb3
|= HB3_AA
;
550 SET_RCODE(header
, NOERROR
);
553 if (extract_addresses(header
, n
, daemon
->namebuff
, now
, sets
, is_sign
, check_rebind
, no_cache
))
555 my_syslog(LOG_WARNING
, _("possible DNS-rebind attack detected: %s"), daemon
->namebuff
);
560 /* do this after extract_addresses. Ensure NODATA reply and remove
565 header
->ancount
= htons(0);
566 header
->nscount
= htons(0);
567 header
->arcount
= htons(0);
570 /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide
571 sections of the packet. Find the new length here and put back pseudoheader
572 if it was removed. */
573 return resize_packet(header
, n
, pheader
, plen
);
576 /* sets new last_server */
577 void reply_query(int fd
, int family
, time_t now
)
579 /* packet from peer server, extract data for cache, and send to
580 original requester */
581 struct dns_header
*header
;
582 union mysockaddr serveraddr
;
583 struct frec
*forward
;
584 socklen_t addrlen
= sizeof(serveraddr
);
585 ssize_t n
= recvfrom(fd
, daemon
->packet
, daemon
->edns_pktsz
, 0, &serveraddr
.sa
, &addrlen
);
587 struct server
*server
;
589 /* packet buffer overwritten */
590 daemon
->srv_save
= NULL
;
592 /* Determine the address of the server replying so that we can mark that as good */
593 serveraddr
.sa
.sa_family
= family
;
595 if (serveraddr
.sa
.sa_family
== AF_INET6
)
596 serveraddr
.in6
.sin6_flowinfo
= 0;
599 /* spoof check: answer must come from known server, */
600 for (server
= daemon
->servers
; server
; server
= server
->next
)
601 if (!(server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_NO_ADDR
)) &&
602 sockaddr_isequal(&server
->addr
, &serveraddr
))
605 header
= (struct dns_header
*)daemon
->packet
;
608 n
< (int)sizeof(struct dns_header
) || !(header
->hb3
& HB3_QR
) ||
609 !(forward
= lookup_frec(ntohs(header
->id
), questions_crc(header
, n
, daemon
->namebuff
))))
612 if ((RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
) &&
613 !option_bool(OPT_ORDER
) &&
614 forward
->forwardall
== 0)
615 /* for broken servers, attempt to send to another one. */
617 unsigned char *pheader
;
621 /* recreate query from reply */
622 pheader
= find_pseudoheader(header
, (size_t)n
, &plen
, NULL
, &is_sign
);
625 header
->ancount
= htons(0);
626 header
->nscount
= htons(0);
627 header
->arcount
= htons(0);
628 if ((nn
= resize_packet(header
, (size_t)n
, pheader
, plen
)))
630 header
->hb3
&= ~(HB3_QR
| HB3_TC
);
631 forward_query(-1, NULL
, NULL
, 0, header
, nn
, now
, forward
);
637 server
= forward
->sentto
;
639 if ((forward
->sentto
->flags
& SERV_TYPE
) == 0)
641 if (RCODE(header
) == SERVFAIL
|| RCODE(header
) == REFUSED
)
645 struct server
*last_server
;
647 /* find good server by address if possible, otherwise assume the last one we sent to */
648 for (last_server
= daemon
->servers
; last_server
; last_server
= last_server
->next
)
649 if (!(last_server
->flags
& (SERV_LITERAL_ADDRESS
| SERV_HAS_DOMAIN
| SERV_FOR_NODOTS
| SERV_NO_ADDR
)) &&
650 sockaddr_isequal(&last_server
->addr
, &serveraddr
))
652 server
= last_server
;
656 if (!option_bool(OPT_ALL_SERVERS
))
657 daemon
->last_server
= server
;
660 /* If the answer is an error, keep the forward record in place in case
661 we get a good reply from another server. Kill it when we've
662 had replies from all to avoid filling the forwarding table when
663 everything is broken */
664 if (forward
->forwardall
== 0 || --forward
->forwardall
== 1 ||
665 (RCODE(header
) != REFUSED
&& RCODE(header
) != SERVFAIL
))
667 int check_rebind
= 0, no_cache_dnssec
= 0, cache_secure
= 0;
669 if (option_bool(OPT_NO_REBIND
))
670 check_rebind
= !(forward
->flags
& FREC_NOREBIND
);
672 /* Don't cache replies where DNSSEC validation was turned off, either
673 the upstream server told us so, or the original query specified it. */
674 if ((header
->hb4
& HB4_CD
) || (forward
->flags
& FREC_CHECKING_DISABLED
))
678 if (option_bool(OPT_DNSSEC_VALID
) && !(forward
->flags
& FREC_CHECKING_DISABLED
))
680 int status
= dnssec_validate(forward
->flags
, header
, n
);
682 /* Can't validate, as we're missing key data. Put this
683 answer aside, whilst we get that. */
684 if (status
== STAT_NEED_DS
|| status
== STAT_NEED_KEY
)
687 if ((forward
->stash
= blockdata_alloc((char *)header
, n
)))
689 forward
->stash_len
= n
;
691 /* Now formulate a query for the missing data. */
692 nn
= dnssec_generate_query(header
, status
);
693 new = get_new_frec(now
, NULL
, 1);
699 new = forward
; /* copy everything, then overwrite */
700 new->dependent
= forward
; /* to find query awaiting new one. */
701 forward
->blocking_query
= new; /* for garbage cleaning */
702 new->flags
|= FREC_DNSSEC_QUERY
;
703 if (status
== STAT_NEED_KEY
)
704 new->flags
|= FREC_DNSKEY_QUERY
; /* So we verify differently */
705 else if (status
== STAT_NEED_DS
)
706 new->flags
|= FREC_DS_QUERY
;
707 new->crc
= questions_crc(header
, nn
, daemon
->namebuff
);
708 new->new_id
= get_id(new->crc
);
710 /* Don't resend this. */
711 daemon
->srv_save
= NULL
;
714 fd
= server
->sfd
->fd
;
717 /* Note that we use the same random port for the DNSSEC stuff */
718 if (server
->addr
.sa
.sa_family
== AF_INET6
)
721 new->rfd6
->refcount
++;
727 new->rfd4
->refcount
++;
730 /* Send DNSSEC query to same server as original query */
731 while (sendto(fd
, (char *)header
, nn
, 0, &server
->addr
.sa
, sa_len(&server
->addr
)) == -1 && retry_send());
737 /* Ok, we reached far enough up the chain-of-trust that we can validate something.
738 Now wind back down, pulling back answers which wouldn't previously validate
739 and validate them with the new data. Failure to find needed data here is an internal error.
740 Once we get to the original answer (FREC_DNSSEC_QUERY not set) and it validates,
741 return it to the original requestor. */
742 while (forward
->flags
& FREC_DNSSEC_QUERY
)
744 if (status
== STAT_SECURE
)
745 extract_dnssec_replies();
747 forward
= forward
->dependent
;
748 blockdata_retrieve_and_free(forward
->stash
, forward
->stash_len
, (void *)header
);
749 n
= forward
->stash_len
;
750 if (status
== STAT_SECURE
)
752 status
= dnssec_validate(forward
->flags
, header
, n
);
753 if (status
== STAT_NEED_DS
|| status
== STAT_NEED_KEY
)
754 my_syslog(LOG_ERR
, _("Unexpected missing data for DNSSEC validation"));
758 if (status
== STAT_SECURE
)
760 /* TODO return SERVFAIL here */
761 else if (status
== STAT_BOGUS
)
766 if ((nn
= process_reply(header
, now
, server
, (size_t)n
, check_rebind
, no_cache_dnssec
, cache_secure
,
767 forward
->flags
& FREC_HAS_SUBNET
, &forward
->source
)))
769 header
->id
= htons(forward
->orig_id
);
770 header
->hb4
|= HB4_RA
; /* recursion if available */
771 send_from(forward
->fd
, option_bool(OPT_NOWILD
) || option_bool (OPT_CLEVERBIND
), daemon
->packet
, nn
,
772 &forward
->source
, &forward
->dest
, forward
->iface
);
774 free_frec(forward
); /* cancel */
779 void receive_query(struct listener
*listen
, time_t now
)
781 struct dns_header
*header
= (struct dns_header
*)daemon
->packet
;
782 union mysockaddr source_addr
;
784 struct all_addr dst_addr
;
785 struct in_addr netmask
, dst_addr_4
;
789 int local_auth
= 0, auth_dns
= 0;
792 struct cmsghdr
*cmptr
;
794 struct cmsghdr align
; /* this ensures alignment */
796 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
798 #if defined(HAVE_LINUX_NETWORK)
799 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
800 #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK)
801 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
802 CMSG_SPACE(sizeof(unsigned int))];
803 #elif defined(IP_RECVDSTADDR)
804 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
805 CMSG_SPACE(sizeof(struct sockaddr_dl
))];
809 /* packet buffer overwritten */
810 daemon
->srv_save
= NULL
;
812 dst_addr_4
.s_addr
= 0;
815 if (option_bool(OPT_NOWILD
) && listen
->iface
)
817 auth_dns
= listen
->iface
->dns_auth
;
819 if (listen
->family
== AF_INET
)
821 dst_addr_4
= listen
->iface
->addr
.in
.sin_addr
;
822 netmask
= listen
->iface
->netmask
;
826 iov
[0].iov_base
= daemon
->packet
;
827 iov
[0].iov_len
= daemon
->edns_pktsz
;
829 msg
.msg_control
= control_u
.control
;
830 msg
.msg_controllen
= sizeof(control_u
);
832 msg
.msg_name
= &source_addr
;
833 msg
.msg_namelen
= sizeof(source_addr
);
837 if ((n
= recvmsg(listen
->fd
, &msg
, 0)) == -1)
840 if (n
< (int)sizeof(struct dns_header
) ||
841 (msg
.msg_flags
& MSG_TRUNC
) ||
842 (header
->hb3
& HB3_QR
))
845 source_addr
.sa
.sa_family
= listen
->family
;
847 if (listen
->family
== AF_INET6
)
848 source_addr
.in6
.sin6_flowinfo
= 0;
851 if (!option_bool(OPT_NOWILD
))
855 if (msg
.msg_controllen
< sizeof(struct cmsghdr
))
858 #if defined(HAVE_LINUX_NETWORK)
859 if (listen
->family
== AF_INET
)
860 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
861 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_PKTINFO
)
865 struct in_pktinfo
*p
;
867 p
.c
= CMSG_DATA(cmptr
);
868 dst_addr_4
= dst_addr
.addr
.addr4
= p
.p
->ipi_spec_dst
;
869 if_index
= p
.p
->ipi_ifindex
;
871 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
872 if (listen
->family
== AF_INET
)
874 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
880 #ifndef HAVE_SOLARIS_NETWORK
881 struct sockaddr_dl
*s
;
884 p
.c
= CMSG_DATA(cmptr
);
885 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
886 dst_addr_4
= dst_addr
.addr
.addr4
= *(p
.a
);
887 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
888 #ifdef HAVE_SOLARIS_NETWORK
891 if_index
= p
.s
->sdl_index
;
898 if (listen
->family
== AF_INET6
)
900 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
901 if (cmptr
->cmsg_level
== IPPROTO_IPV6
&& cmptr
->cmsg_type
== daemon
->v6pktinfo
)
905 struct in6_pktinfo
*p
;
907 p
.c
= CMSG_DATA(cmptr
);
909 dst_addr
.addr
.addr6
= p
.p
->ipi6_addr
;
910 if_index
= p
.p
->ipi6_ifindex
;
915 /* enforce available interface configuration */
917 if (!indextoname(listen
->fd
, if_index
, ifr
.ifr_name
))
920 if (!iface_check(listen
->family
, &dst_addr
, ifr
.ifr_name
, &auth_dns
))
922 if (!option_bool(OPT_CLEVERBIND
))
923 enumerate_interfaces(0);
924 if (!loopback_exception(listen
->fd
, listen
->family
, &dst_addr
, ifr
.ifr_name
) &&
925 !label_exception(if_index
, listen
->family
, &dst_addr
))
929 if (listen
->family
== AF_INET
&& option_bool(OPT_LOCALISE
))
933 /* get the netmask of the interface whch has the address we were sent to.
934 This is no neccessarily the interface we arrived on. */
936 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
937 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
938 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
941 /* interface may be new */
942 if (!iface
&& !option_bool(OPT_CLEVERBIND
))
943 enumerate_interfaces(0);
945 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
946 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
947 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
950 /* If we failed, abandon localisation */
952 netmask
= iface
->netmask
;
954 dst_addr_4
.s_addr
= 0;
958 if (extract_request(header
, (size_t)n
, daemon
->namebuff
, &type
))
962 struct auth_zone
*zone
;
965 querystr(auth_dns
? "auth" : "query", types
, type
);
967 if (listen
->family
== AF_INET
)
968 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
969 (struct all_addr
*)&source_addr
.in
.sin_addr
, types
);
972 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
973 (struct all_addr
*)&source_addr
.in6
.sin6_addr
, types
);
977 /* find queries for zones we're authoritative for, and answer them directly */
979 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
980 if (in_zone(zone
, daemon
->namebuff
, NULL
))
992 m
= answer_auth(header
, ((char *) header
) + PACKETSZ
, (size_t)n
, now
, &source_addr
, local_auth
);
995 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
996 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
997 daemon
->auth_answer
++;
1003 m
= answer_request(header
, ((char *) header
) + PACKETSZ
, (size_t)n
,
1004 dst_addr_4
, netmask
, now
);
1008 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
1009 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
1010 daemon
->local_answer
++;
1012 else if (forward_query(listen
->fd
, &source_addr
, &dst_addr
, if_index
,
1013 header
, (size_t)n
, now
, NULL
))
1014 daemon
->queries_forwarded
++;
1016 daemon
->local_answer
++;
1020 /* The daemon forks before calling this: it should deal with one connection,
1021 blocking as neccessary, and then return. Note, need to be a bit careful
1022 about resources for debug mode, when the fork is suppressed: that's
1023 done by the caller. */
1024 unsigned char *tcp_request(int confd
, time_t now
,
1025 union mysockaddr
*local_addr
, struct in_addr netmask
, int auth_dns
)
1030 int checking_disabled
, check_subnet
;
1032 unsigned short qtype
;
1033 unsigned int gotname
;
1034 unsigned char c1
, c2
;
1035 /* Max TCP packet + slop + size */
1036 unsigned char *packet
= whine_malloc(65536 + MAXDNAME
+ RRFIXEDSZ
+ sizeof(u16
));
1037 unsigned char *payload
= &packet
[2];
1038 /* largest field in header is 16-bits, so this is still sufficiently aligned */
1039 struct dns_header
*header
= (struct dns_header
*)payload
;
1040 u16
*length
= (u16
*)packet
;
1041 struct server
*last_server
;
1042 struct in_addr dst_addr_4
;
1043 union mysockaddr peer_addr
;
1044 socklen_t peer_len
= sizeof(union mysockaddr
);
1046 if (getpeername(confd
, (struct sockaddr
*)&peer_addr
, &peer_len
) == -1)
1052 !read_write(confd
, &c1
, 1, 1) || !read_write(confd
, &c2
, 1, 1) ||
1053 !(size
= c1
<< 8 | c2
) ||
1054 !read_write(confd
, payload
, size
, 1))
1057 if (size
< (int)sizeof(struct dns_header
))
1062 /* save state of "cd" flag in query */
1063 checking_disabled
= header
->hb4
& HB4_CD
;
1065 /* RFC 4035: sect 4.6 para 2 */
1066 header
->hb4
&= ~HB4_AD
;
1068 if ((gotname
= extract_request(header
, (unsigned int)size
, daemon
->namebuff
, &qtype
)))
1072 struct auth_zone
*zone
;
1074 querystr(auth_dns
? "auth" : "query", types
, qtype
);
1076 if (peer_addr
.sa
.sa_family
== AF_INET
)
1077 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1078 (struct all_addr
*)&peer_addr
.in
.sin_addr
, types
);
1081 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1082 (struct all_addr
*)&peer_addr
.in6
.sin6_addr
, types
);
1086 /* find queries for zones we're authoritative for, and answer them directly */
1088 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
1089 if (in_zone(zone
, daemon
->namebuff
, NULL
))
1098 if (local_addr
->sa
.sa_family
== AF_INET
)
1099 dst_addr_4
= local_addr
->in
.sin_addr
;
1101 dst_addr_4
.s_addr
= 0;
1105 m
= answer_auth(header
, ((char *) header
) + 65536, (size_t)size
, now
, &peer_addr
, local_auth
);
1109 /* m > 0 if answered from cache */
1110 m
= answer_request(header
, ((char *) header
) + 65536, (size_t)size
,
1111 dst_addr_4
, netmask
, now
);
1113 /* Do this by steam now we're not in the select() loop */
1114 check_log_writer(NULL
);
1118 unsigned int flags
= 0;
1119 struct all_addr
*addrp
= NULL
;
1121 char *domain
= NULL
;
1123 if (option_bool(OPT_ADD_MAC
))
1124 size
= add_mac(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1126 if (option_bool(OPT_CLIENT_SUBNET
))
1128 size_t new = add_source_addr(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1137 flags
= search_servers(now
, &addrp
, gotname
, daemon
->namebuff
, &type
, &domain
, &norebind
);
1139 if (type
!= 0 || option_bool(OPT_ORDER
) || !daemon
->last_server
)
1140 last_server
= daemon
->servers
;
1142 last_server
= daemon
->last_server
;
1144 if (!flags
&& last_server
)
1146 struct server
*firstsendto
= NULL
;
1147 unsigned int crc
= questions_crc(header
, (unsigned int)size
, daemon
->namebuff
);
1149 /* Loop round available servers until we succeed in connecting to one.
1150 Note that this code subtley ensures that consecutive queries on this connection
1151 which can go to the same server, do so. */
1155 firstsendto
= last_server
;
1158 if (!(last_server
= last_server
->next
))
1159 last_server
= daemon
->servers
;
1161 if (last_server
== firstsendto
)
1165 /* server for wrong domain */
1166 if (type
!= (last_server
->flags
& SERV_TYPE
) ||
1167 (type
== SERV_HAS_DOMAIN
&& !hostname_isequal(domain
, last_server
->domain
)))
1170 if (last_server
->tcpfd
== -1)
1172 if ((last_server
->tcpfd
= socket(last_server
->addr
.sa
.sa_family
, SOCK_STREAM
, 0)) == -1)
1175 if ((!local_bind(last_server
->tcpfd
, &last_server
->source_addr
, last_server
->interface
, 1) ||
1176 connect(last_server
->tcpfd
, &last_server
->addr
.sa
, sa_len(&last_server
->addr
)) == -1))
1178 close(last_server
->tcpfd
);
1179 last_server
->tcpfd
= -1;
1183 #ifdef HAVE_CONNTRACK
1184 /* Copy connection mark of incoming query to outgoing connection. */
1185 if (option_bool(OPT_CONNTRACK
))
1188 struct all_addr local
;
1190 if (local_addr
->sa
.sa_family
== AF_INET6
)
1191 local
.addr
.addr6
= local_addr
->in6
.sin6_addr
;
1194 local
.addr
.addr4
= local_addr
->in
.sin_addr
;
1196 if (get_incoming_mark(&peer_addr
, &local
, 1, &mark
))
1197 setsockopt(last_server
->tcpfd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
1202 *length
= htons(size
);
1204 if (!read_write(last_server
->tcpfd
, packet
, size
+ sizeof(u16
), 0) ||
1205 !read_write(last_server
->tcpfd
, &c1
, 1, 1) ||
1206 !read_write(last_server
->tcpfd
, &c2
, 1, 1))
1208 close(last_server
->tcpfd
);
1209 last_server
->tcpfd
= -1;
1214 if (!read_write(last_server
->tcpfd
, payload
, m
, 1))
1218 strcpy(daemon
->namebuff
, "query");
1219 if (last_server
->addr
.sa
.sa_family
== AF_INET
)
1220 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1221 (struct all_addr
*)&last_server
->addr
.in
.sin_addr
, NULL
);
1224 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1225 (struct all_addr
*)&last_server
->addr
.in6
.sin6_addr
, NULL
);
1228 /* There's no point in updating the cache, since this process will exit and
1229 lose the information after a few queries. We make this call for the alias and
1230 bogus-nxdomain side-effects. */
1231 /* If the crc of the question section doesn't match the crc we sent, then
1232 someone might be attempting to insert bogus values into the cache by
1233 sending replies containing questions and bogus answers. */
1234 if (crc
== questions_crc(header
, (unsigned int)m
, daemon
->namebuff
))
1235 m
= process_reply(header
, now
, last_server
, (unsigned int)m
,
1236 option_bool(OPT_NO_REBIND
) && !norebind
, checking_disabled
,
1237 0, check_subnet
, &peer_addr
); /* TODO - cache secure */
1243 /* In case of local answer or no connections made. */
1245 m
= setup_reply(header
, (unsigned int)size
, addrp
, flags
, daemon
->local_ttl
);
1249 check_log_writer(NULL
);
1253 if (m
== 0 || !read_write(confd
, packet
, m
+ sizeof(u16
), 0))
1258 static struct frec
*allocate_frec(time_t now
)
1262 if ((f
= (struct frec
*)whine_malloc(sizeof(struct frec
))))
1264 f
->next
= daemon
->frec_list
;
1273 f
->blocking_query
= NULL
;
1275 daemon
->frec_list
= f
;
1281 static struct randfd
*allocate_rfd(int family
)
1283 static int finger
= 0;
1286 /* limit the number of sockets we have open to avoid starvation of
1287 (eg) TFTP. Once we have a reasonable number, randomness should be OK */
1289 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1290 if (daemon
->randomsocks
[i
].refcount
== 0)
1292 if ((daemon
->randomsocks
[i
].fd
= random_sock(family
)) == -1)
1295 daemon
->randomsocks
[i
].refcount
= 1;
1296 daemon
->randomsocks
[i
].family
= family
;
1297 return &daemon
->randomsocks
[i
];
1300 /* No free ones or cannot get new socket, grab an existing one */
1301 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1303 int j
= (i
+finger
) % RANDOM_SOCKS
;
1304 if (daemon
->randomsocks
[j
].refcount
!= 0 &&
1305 daemon
->randomsocks
[j
].family
== family
&&
1306 daemon
->randomsocks
[j
].refcount
!= 0xffff)
1309 daemon
->randomsocks
[j
].refcount
++;
1310 return &daemon
->randomsocks
[j
];
1314 return NULL
; /* doom */
1317 static void free_frec(struct frec
*f
)
1319 if (f
->rfd4
&& --(f
->rfd4
->refcount
) == 0)
1327 if (f
->rfd6
&& --(f
->rfd6
->refcount
) == 0)
1335 blockdata_free(f
->stash
);
1337 /* Anything we're waiting on is pointless now, too */
1338 if (f
->blocking_query
)
1339 free_frec(f
->blocking_query
);
1340 f
->blocking_query
= NULL
;
1345 /* if wait==NULL return a free or older than TIMEOUT record.
1346 else return *wait zero if one available, or *wait is delay to
1347 when the oldest in-use record will expire. Impose an absolute
1348 limit of 4*TIMEOUT before we wipe things (for random sockets).
1349 If force is set, always return a result, even if we have
1350 to allocate above the limit. */
1351 struct frec
*get_new_frec(time_t now
, int *wait
, int force
)
1353 struct frec
*f
, *oldest
, *target
;
1359 for (f
= daemon
->frec_list
, oldest
= NULL
, target
= NULL
, count
= 0; f
; f
= f
->next
, count
++)
1364 if (difftime(now
, f
->time
) >= 4*TIMEOUT
)
1370 if (!oldest
|| difftime(f
->time
, oldest
->time
) <= 0)
1380 /* can't find empty one, use oldest if there is one
1381 and it's older than timeout */
1382 if (oldest
&& ((int)difftime(now
, oldest
->time
)) >= TIMEOUT
)
1384 /* keep stuff for twice timeout if we can by allocating a new
1386 if (difftime(now
, oldest
->time
) < 2*TIMEOUT
&&
1387 count
<= daemon
->ftabsize
&&
1388 (f
= allocate_frec(now
)))
1399 /* none available, calculate time 'till oldest record expires */
1400 if (!force
&& count
> daemon
->ftabsize
)
1402 static time_t last_log
= 0;
1405 *wait
= oldest
->time
+ (time_t)TIMEOUT
- now
;
1407 if ((int)difftime(now
, last_log
) > 5)
1410 my_syslog(LOG_WARNING
, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon
->ftabsize
);
1416 if (!(f
= allocate_frec(now
)) && wait
)
1417 /* wait one second on malloc failure */
1420 return f
; /* OK if malloc fails and this is NULL */
1423 /* crc is all-ones if not known. */
1424 static struct frec
*lookup_frec(unsigned short id
, unsigned int crc
)
1428 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1429 if (f
->sentto
&& f
->new_id
== id
&&
1430 (f
->crc
== crc
|| crc
== 0xffffffff))
1436 static struct frec
*lookup_frec_by_sender(unsigned short id
,
1437 union mysockaddr
*addr
,
1442 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1446 sockaddr_isequal(&f
->source
, addr
))
1452 /* A server record is going away, remove references to it */
1453 void server_gone(struct server
*server
)
1457 for (f
= daemon
->frec_list
; f
; f
= f
->next
)
1458 if (f
->sentto
&& f
->sentto
== server
)
1461 if (daemon
->last_server
== server
)
1462 daemon
->last_server
= NULL
;
1464 if (daemon
->srv_save
== server
)
1465 daemon
->srv_save
= NULL
;
1468 /* return unique random ids. */
1469 static unsigned short get_id(unsigned int crc
)
1471 unsigned short ret
= 0;
1475 while (lookup_frec(ret
, crc
));