]>
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
;
788 int if_index
= 0, auth_dns
= 0;
794 struct cmsghdr
*cmptr
;
796 struct cmsghdr align
; /* this ensures alignment */
798 char control6
[CMSG_SPACE(sizeof(struct in6_pktinfo
))];
800 #if defined(HAVE_LINUX_NETWORK)
801 char control
[CMSG_SPACE(sizeof(struct in_pktinfo
))];
802 #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK)
803 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
804 CMSG_SPACE(sizeof(unsigned int))];
805 #elif defined(IP_RECVDSTADDR)
806 char control
[CMSG_SPACE(sizeof(struct in_addr
)) +
807 CMSG_SPACE(sizeof(struct sockaddr_dl
))];
811 /* Can always get recvd interface for IPv6 */
812 int check_dst
= !option_bool(OPT_NOWILD
) || listen
->family
== AF_INET6
;
814 int check_dst
= !option_bool(OPT_NOWILD
);
817 /* packet buffer overwritten */
818 daemon
->srv_save
= NULL
;
820 dst_addr_4
.s_addr
= 0;
823 if (option_bool(OPT_NOWILD
) && listen
->iface
)
825 auth_dns
= listen
->iface
->dns_auth
;
827 if (listen
->family
== AF_INET
)
829 dst_addr_4
= listen
->iface
->addr
.in
.sin_addr
;
830 netmask
= listen
->iface
->netmask
;
834 iov
[0].iov_base
= daemon
->packet
;
835 iov
[0].iov_len
= daemon
->edns_pktsz
;
837 msg
.msg_control
= control_u
.control
;
838 msg
.msg_controllen
= sizeof(control_u
);
840 msg
.msg_name
= &source_addr
;
841 msg
.msg_namelen
= sizeof(source_addr
);
845 if ((n
= recvmsg(listen
->fd
, &msg
, 0)) == -1)
848 if (n
< (int)sizeof(struct dns_header
) ||
849 (msg
.msg_flags
& MSG_TRUNC
) ||
850 (header
->hb3
& HB3_QR
))
853 source_addr
.sa
.sa_family
= listen
->family
;
855 if (listen
->family
== AF_INET6
)
856 source_addr
.in6
.sin6_flowinfo
= 0;
863 if (msg
.msg_controllen
< sizeof(struct cmsghdr
))
866 #if defined(HAVE_LINUX_NETWORK)
867 if (listen
->family
== AF_INET
)
868 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
869 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_PKTINFO
)
873 struct in_pktinfo
*p
;
875 p
.c
= CMSG_DATA(cmptr
);
876 dst_addr_4
= dst_addr
.addr
.addr4
= p
.p
->ipi_spec_dst
;
877 if_index
= p
.p
->ipi_ifindex
;
879 #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF)
880 if (listen
->family
== AF_INET
)
882 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
888 #ifndef HAVE_SOLARIS_NETWORK
889 struct sockaddr_dl
*s
;
892 p
.c
= CMSG_DATA(cmptr
);
893 if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVDSTADDR
)
894 dst_addr_4
= dst_addr
.addr
.addr4
= *(p
.a
);
895 else if (cmptr
->cmsg_level
== IPPROTO_IP
&& cmptr
->cmsg_type
== IP_RECVIF
)
896 #ifdef HAVE_SOLARIS_NETWORK
899 if_index
= p
.s
->sdl_index
;
906 if (listen
->family
== AF_INET6
)
908 for (cmptr
= CMSG_FIRSTHDR(&msg
); cmptr
; cmptr
= CMSG_NXTHDR(&msg
, cmptr
))
909 if (cmptr
->cmsg_level
== IPPROTO_IPV6
&& cmptr
->cmsg_type
== daemon
->v6pktinfo
)
913 struct in6_pktinfo
*p
;
915 p
.c
= CMSG_DATA(cmptr
);
917 dst_addr
.addr
.addr6
= p
.p
->ipi6_addr
;
918 if_index
= p
.p
->ipi6_ifindex
;
923 /* enforce available interface configuration */
925 if (!indextoname(listen
->fd
, if_index
, ifr
.ifr_name
))
928 if (!iface_check(listen
->family
, &dst_addr
, ifr
.ifr_name
, &auth_dns
))
930 if (!option_bool(OPT_CLEVERBIND
))
931 enumerate_interfaces(0);
932 if (!loopback_exception(listen
->fd
, listen
->family
, &dst_addr
, ifr
.ifr_name
) &&
933 !label_exception(if_index
, listen
->family
, &dst_addr
))
937 if (listen
->family
== AF_INET
&& option_bool(OPT_LOCALISE
))
941 /* get the netmask of the interface whch has the address we were sent to.
942 This is no neccessarily the interface we arrived on. */
944 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
945 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
946 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
949 /* interface may be new */
950 if (!iface
&& !option_bool(OPT_CLEVERBIND
))
951 enumerate_interfaces(0);
953 for (iface
= daemon
->interfaces
; iface
; iface
= iface
->next
)
954 if (iface
->addr
.sa
.sa_family
== AF_INET
&&
955 iface
->addr
.in
.sin_addr
.s_addr
== dst_addr_4
.s_addr
)
958 /* If we failed, abandon localisation */
960 netmask
= iface
->netmask
;
962 dst_addr_4
.s_addr
= 0;
966 if (extract_request(header
, (size_t)n
, daemon
->namebuff
, &type
))
970 struct auth_zone
*zone
;
973 querystr(auth_dns
? "auth" : "query", types
, type
);
975 if (listen
->family
== AF_INET
)
976 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
977 (struct all_addr
*)&source_addr
.in
.sin_addr
, types
);
980 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
981 (struct all_addr
*)&source_addr
.in6
.sin6_addr
, types
);
985 /* find queries for zones we're authoritative for, and answer them directly */
987 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
988 if (in_zone(zone
, daemon
->namebuff
, NULL
))
1000 m
= answer_auth(header
, ((char *) header
) + PACKETSZ
, (size_t)n
, now
, &source_addr
, local_auth
);
1003 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
1004 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
1005 daemon
->auth_answer
++;
1011 m
= answer_request(header
, ((char *) header
) + PACKETSZ
, (size_t)n
,
1012 dst_addr_4
, netmask
, now
);
1016 send_from(listen
->fd
, option_bool(OPT_NOWILD
) || option_bool(OPT_CLEVERBIND
),
1017 (char *)header
, m
, &source_addr
, &dst_addr
, if_index
);
1018 daemon
->local_answer
++;
1020 else if (forward_query(listen
->fd
, &source_addr
, &dst_addr
, if_index
,
1021 header
, (size_t)n
, now
, NULL
))
1022 daemon
->queries_forwarded
++;
1024 daemon
->local_answer
++;
1028 /* The daemon forks before calling this: it should deal with one connection,
1029 blocking as neccessary, and then return. Note, need to be a bit careful
1030 about resources for debug mode, when the fork is suppressed: that's
1031 done by the caller. */
1032 unsigned char *tcp_request(int confd
, time_t now
,
1033 union mysockaddr
*local_addr
, struct in_addr netmask
, int auth_dns
)
1040 int checking_disabled
, check_subnet
;
1042 unsigned short qtype
;
1043 unsigned int gotname
;
1044 unsigned char c1
, c2
;
1045 /* Max TCP packet + slop + size */
1046 unsigned char *packet
= whine_malloc(65536 + MAXDNAME
+ RRFIXEDSZ
+ sizeof(u16
));
1047 unsigned char *payload
= &packet
[2];
1048 /* largest field in header is 16-bits, so this is still sufficiently aligned */
1049 struct dns_header
*header
= (struct dns_header
*)payload
;
1050 u16
*length
= (u16
*)packet
;
1051 struct server
*last_server
;
1052 struct in_addr dst_addr_4
;
1053 union mysockaddr peer_addr
;
1054 socklen_t peer_len
= sizeof(union mysockaddr
);
1056 if (getpeername(confd
, (struct sockaddr
*)&peer_addr
, &peer_len
) == -1)
1062 !read_write(confd
, &c1
, 1, 1) || !read_write(confd
, &c2
, 1, 1) ||
1063 !(size
= c1
<< 8 | c2
) ||
1064 !read_write(confd
, payload
, size
, 1))
1067 if (size
< (int)sizeof(struct dns_header
))
1072 /* save state of "cd" flag in query */
1073 checking_disabled
= header
->hb4
& HB4_CD
;
1075 /* RFC 4035: sect 4.6 para 2 */
1076 header
->hb4
&= ~HB4_AD
;
1078 if ((gotname
= extract_request(header
, (unsigned int)size
, daemon
->namebuff
, &qtype
)))
1082 struct auth_zone
*zone
;
1084 querystr(auth_dns
? "auth" : "query", types
, qtype
);
1086 if (peer_addr
.sa
.sa_family
== AF_INET
)
1087 log_query(F_QUERY
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1088 (struct all_addr
*)&peer_addr
.in
.sin_addr
, types
);
1091 log_query(F_QUERY
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1092 (struct all_addr
*)&peer_addr
.in6
.sin6_addr
, types
);
1096 /* find queries for zones we're authoritative for, and answer them directly */
1098 for (zone
= daemon
->auth_zones
; zone
; zone
= zone
->next
)
1099 if (in_zone(zone
, daemon
->namebuff
, NULL
))
1108 if (local_addr
->sa
.sa_family
== AF_INET
)
1109 dst_addr_4
= local_addr
->in
.sin_addr
;
1111 dst_addr_4
.s_addr
= 0;
1115 m
= answer_auth(header
, ((char *) header
) + 65536, (size_t)size
, now
, &peer_addr
, local_auth
);
1119 /* m > 0 if answered from cache */
1120 m
= answer_request(header
, ((char *) header
) + 65536, (size_t)size
,
1121 dst_addr_4
, netmask
, now
);
1123 /* Do this by steam now we're not in the select() loop */
1124 check_log_writer(NULL
);
1128 unsigned int flags
= 0;
1129 struct all_addr
*addrp
= NULL
;
1131 char *domain
= NULL
;
1133 if (option_bool(OPT_ADD_MAC
))
1134 size
= add_mac(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1136 if (option_bool(OPT_CLIENT_SUBNET
))
1138 size_t new = add_source_addr(header
, size
, ((char *) header
) + 65536, &peer_addr
);
1147 flags
= search_servers(now
, &addrp
, gotname
, daemon
->namebuff
, &type
, &domain
, &norebind
);
1149 if (type
!= 0 || option_bool(OPT_ORDER
) || !daemon
->last_server
)
1150 last_server
= daemon
->servers
;
1152 last_server
= daemon
->last_server
;
1154 if (!flags
&& last_server
)
1156 struct server
*firstsendto
= NULL
;
1157 unsigned int crc
= questions_crc(header
, (unsigned int)size
, daemon
->namebuff
);
1159 /* Loop round available servers until we succeed in connecting to one.
1160 Note that this code subtley ensures that consecutive queries on this connection
1161 which can go to the same server, do so. */
1165 firstsendto
= last_server
;
1168 if (!(last_server
= last_server
->next
))
1169 last_server
= daemon
->servers
;
1171 if (last_server
== firstsendto
)
1175 /* server for wrong domain */
1176 if (type
!= (last_server
->flags
& SERV_TYPE
) ||
1177 (type
== SERV_HAS_DOMAIN
&& !hostname_isequal(domain
, last_server
->domain
)))
1180 if (last_server
->tcpfd
== -1)
1182 if ((last_server
->tcpfd
= socket(last_server
->addr
.sa
.sa_family
, SOCK_STREAM
, 0)) == -1)
1185 if ((!local_bind(last_server
->tcpfd
, &last_server
->source_addr
, last_server
->interface
, 1) ||
1186 connect(last_server
->tcpfd
, &last_server
->addr
.sa
, sa_len(&last_server
->addr
)) == -1))
1188 close(last_server
->tcpfd
);
1189 last_server
->tcpfd
= -1;
1193 #ifdef HAVE_CONNTRACK
1194 /* Copy connection mark of incoming query to outgoing connection. */
1195 if (option_bool(OPT_CONNTRACK
))
1198 struct all_addr local
;
1200 if (local_addr
->sa
.sa_family
== AF_INET6
)
1201 local
.addr
.addr6
= local_addr
->in6
.sin6_addr
;
1204 local
.addr
.addr4
= local_addr
->in
.sin_addr
;
1206 if (get_incoming_mark(&peer_addr
, &local
, 1, &mark
))
1207 setsockopt(last_server
->tcpfd
, SOL_SOCKET
, SO_MARK
, &mark
, sizeof(unsigned int));
1212 *length
= htons(size
);
1214 if (!read_write(last_server
->tcpfd
, packet
, size
+ sizeof(u16
), 0) ||
1215 !read_write(last_server
->tcpfd
, &c1
, 1, 1) ||
1216 !read_write(last_server
->tcpfd
, &c2
, 1, 1))
1218 close(last_server
->tcpfd
);
1219 last_server
->tcpfd
= -1;
1224 if (!read_write(last_server
->tcpfd
, payload
, m
, 1))
1228 strcpy(daemon
->namebuff
, "query");
1229 if (last_server
->addr
.sa
.sa_family
== AF_INET
)
1230 log_query(F_SERVER
| F_IPV4
| F_FORWARD
, daemon
->namebuff
,
1231 (struct all_addr
*)&last_server
->addr
.in
.sin_addr
, NULL
);
1234 log_query(F_SERVER
| F_IPV6
| F_FORWARD
, daemon
->namebuff
,
1235 (struct all_addr
*)&last_server
->addr
.in6
.sin6_addr
, NULL
);
1238 /* There's no point in updating the cache, since this process will exit and
1239 lose the information after a few queries. We make this call for the alias and
1240 bogus-nxdomain side-effects. */
1241 /* If the crc of the question section doesn't match the crc we sent, then
1242 someone might be attempting to insert bogus values into the cache by
1243 sending replies containing questions and bogus answers. */
1244 if (crc
== questions_crc(header
, (unsigned int)m
, daemon
->namebuff
))
1245 m
= process_reply(header
, now
, last_server
, (unsigned int)m
,
1246 option_bool(OPT_NO_REBIND
) && !norebind
, checking_disabled
,
1247 0, check_subnet
, &peer_addr
); /* TODO - cache secure */
1253 /* In case of local answer or no connections made. */
1255 m
= setup_reply(header
, (unsigned int)size
, addrp
, flags
, daemon
->local_ttl
);
1259 check_log_writer(NULL
);
1263 if (m
== 0 || !read_write(confd
, packet
, m
+ sizeof(u16
), 0))
1268 static struct frec
*allocate_frec(time_t now
)
1272 if ((f
= (struct frec
*)whine_malloc(sizeof(struct frec
))))
1274 f
->next
= daemon
->frec_list
;
1283 f
->blocking_query
= NULL
;
1285 daemon
->frec_list
= f
;
1291 static struct randfd
*allocate_rfd(int family
)
1293 static int finger
= 0;
1296 /* limit the number of sockets we have open to avoid starvation of
1297 (eg) TFTP. Once we have a reasonable number, randomness should be OK */
1299 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1300 if (daemon
->randomsocks
[i
].refcount
== 0)
1302 if ((daemon
->randomsocks
[i
].fd
= random_sock(family
)) == -1)
1305 daemon
->randomsocks
[i
].refcount
= 1;
1306 daemon
->randomsocks
[i
].family
= family
;
1307 return &daemon
->randomsocks
[i
];
1310 /* No free ones or cannot get new socket, grab an existing one */
1311 for (i
= 0; i
< RANDOM_SOCKS
; i
++)
1313 int j
= (i
+finger
) % RANDOM_SOCKS
;
1314 if (daemon
->randomsocks
[j
].refcount
!= 0 &&
1315 daemon
->randomsocks
[j
].family
== family
&&
1316 daemon
->randomsocks
[j
].refcount
!= 0xffff)
1319 daemon
->randomsocks
[j
].refcount
++;
1320 return &daemon
->randomsocks
[j
];
1324 return NULL
; /* doom */
1327 static void free_frec(struct frec
*f
)
1329 if (f
->rfd4
&& --(f
->rfd4
->refcount
) == 0)
1337 if (f
->rfd6
&& --(f
->rfd6
->refcount
) == 0)
1345 blockdata_free(f
->stash
);
1347 /* Anything we're waiting on is pointless now, too */
1348 if (f
->blocking_query
)
1349 free_frec(f
->blocking_query
);
1350 f
->blocking_query
= NULL
;
1355 /* if wait==NULL return a free or older than TIMEOUT record.
1356 else return *wait zero if one available, or *wait is delay to
1357 when the oldest in-use record will expire. Impose an absolute
1358 limit of 4*TIMEOUT before we wipe things (for random sockets).
1359 If force is set, always return a result, even if we have
1360 to allocate above the limit. */
1361 struct frec
*get_new_frec(time_t now
, int *wait
, int force
)
1363 struct frec
*f
, *oldest
, *target
;
1369 for (f
= daemon
->frec_list
, oldest
= NULL
, target
= NULL
, count
= 0; f
; f
= f
->next
, count
++)
1374 if (difftime(now
, f
->time
) >= 4*TIMEOUT
)
1380 if (!oldest
|| difftime(f
->time
, oldest
->time
) <= 0)
1390 /* can't find empty one, use oldest if there is one
1391 and it's older than timeout */
1392 if (oldest
&& ((int)difftime(now
, oldest
->time
)) >= TIMEOUT
)
1394 /* keep stuff for twice timeout if we can by allocating a new
1396 if (difftime(now
, oldest
->time
) < 2*TIMEOUT
&&
1397 count
<= daemon
->ftabsize
&&
1398 (f
= allocate_frec(now
)))
1409 /* none available, calculate time 'till oldest record expires */
1410 if (!force
&& count
> daemon
->ftabsize
)
1412 static time_t last_log
= 0;
1415 *wait
= oldest
->time
+ (time_t)TIMEOUT
- now
;
1417 if ((int)difftime(now
, last_log
) > 5)
1420 my_syslog(LOG_WARNING
, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon
->ftabsize
);
1426 if (!(f
= allocate_frec(now
)) && wait
)
1427 /* wait one second on malloc failure */
1430 return f
; /* OK if malloc fails and this is NULL */
1433 /* crc is all-ones if not known. */
1434 static struct frec
*lookup_frec(unsigned short id
, unsigned int crc
)
1438 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1439 if (f
->sentto
&& f
->new_id
== id
&&
1440 (f
->crc
== crc
|| crc
== 0xffffffff))
1446 static struct frec
*lookup_frec_by_sender(unsigned short id
,
1447 union mysockaddr
*addr
,
1452 for(f
= daemon
->frec_list
; f
; f
= f
->next
)
1456 sockaddr_isequal(&f
->source
, addr
))
1462 /* A server record is going away, remove references to it */
1463 void server_gone(struct server
*server
)
1467 for (f
= daemon
->frec_list
; f
; f
= f
->next
)
1468 if (f
->sentto
&& f
->sentto
== server
)
1471 if (daemon
->last_server
== server
)
1472 daemon
->last_server
= NULL
;
1474 if (daemon
->srv_save
== server
)
1475 daemon
->srv_save
= NULL
;
1478 /* return unique random ids. */
1479 static unsigned short get_id(unsigned int crc
)
1481 unsigned short ret
= 0;
1485 while (lookup_frec(ret
, crc
));