1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2014 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <netinet/tcp.h>
25 #include "alloc-util.h"
26 #include "dns-domain.h"
28 #include "hostname-util.h"
30 #include "random-util.h"
31 #include "resolved-dns-scope.h"
32 #include "resolved-llmnr.h"
33 #include "resolved-mdns.h"
34 #include "socket-util.h"
37 #define MULTICAST_RATELIMIT_INTERVAL_USEC (1*USEC_PER_SEC)
38 #define MULTICAST_RATELIMIT_BURST 1000
40 /* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
41 #define MULTICAST_RESEND_TIMEOUT_MIN_USEC (100 * USEC_PER_MSEC)
42 #define MULTICAST_RESEND_TIMEOUT_MAX_USEC (1 * USEC_PER_SEC)
44 int dns_scope_new(Manager
*m
, DnsScope
**ret
, Link
*l
, DnsProtocol protocol
, int family
) {
50 s
= new0(DnsScope
, 1);
56 s
->protocol
= protocol
;
58 s
->resend_timeout
= MULTICAST_RESEND_TIMEOUT_MIN_USEC
;
60 s
->dnssec_mode
= _DNSSEC_MODE_INVALID
;
62 if (protocol
== DNS_PROTOCOL_DNS
) {
63 /* Copy DNSSEC mode from the link if it is set there,
64 * otherwise take the manager's DNSSEC mode. Note that
65 * we copy this only at scope creation time, and do
66 * not update it from the on, even if the setting
70 s
->dnssec_mode
= l
->dnssec_mode
;
71 if (s
->dnssec_mode
== _DNSSEC_MODE_INVALID
)
72 s
->dnssec_mode
= m
->dnssec_mode
;
73 if (s
->dnssec_mode
== _DNSSEC_MODE_INVALID
)
74 s
->dnssec_mode
= DNSSEC_NO
;
77 LIST_PREPEND(scopes
, m
->dns_scopes
, s
);
79 dns_scope_llmnr_membership(s
, true);
80 dns_scope_mdns_membership(s
, true);
82 log_debug("New scope on link %s, protocol %s, family %s", l
? l
->name
: "*", dns_protocol_to_string(protocol
), family
== AF_UNSPEC
? "*" : af_to_name(family
));
84 /* Enforce ratelimiting for the multicast protocols */
85 RATELIMIT_INIT(s
->ratelimit
, MULTICAST_RATELIMIT_INTERVAL_USEC
, MULTICAST_RATELIMIT_BURST
);
91 static void dns_scope_abort_transactions(DnsScope
*s
) {
94 while (s
->transactions
) {
95 DnsTransaction
*t
= s
->transactions
;
97 /* Abort the transaction, but make sure it is not
98 * freed while we still look at it */
101 if (DNS_TRANSACTION_IS_LIVE(t
->state
))
102 dns_transaction_complete(t
, DNS_TRANSACTION_ABORTED
);
105 dns_transaction_free(t
);
109 DnsScope
* dns_scope_free(DnsScope
*s
) {
110 DnsResourceRecord
*rr
;
115 log_debug("Removing scope on link %s, protocol %s, family %s", s
->link
? s
->link
->name
: "*", dns_protocol_to_string(s
->protocol
), s
->family
== AF_UNSPEC
? "*" : af_to_name(s
->family
));
117 dns_scope_llmnr_membership(s
, false);
118 dns_scope_mdns_membership(s
, false);
119 dns_scope_abort_transactions(s
);
121 while (s
->query_candidates
)
122 dns_query_candidate_free(s
->query_candidates
);
124 hashmap_free(s
->transactions_by_key
);
126 while ((rr
= ordered_hashmap_steal_first(s
->conflict_queue
)))
127 dns_resource_record_unref(rr
);
129 ordered_hashmap_free(s
->conflict_queue
);
130 sd_event_source_unref(s
->conflict_event_source
);
132 dns_cache_flush(&s
->cache
);
133 dns_zone_flush(&s
->zone
);
135 LIST_REMOVE(scopes
, s
->manager
->dns_scopes
, s
);
141 DnsServer
*dns_scope_get_dns_server(DnsScope
*s
) {
144 if (s
->protocol
!= DNS_PROTOCOL_DNS
)
148 return link_get_dns_server(s
->link
);
150 return manager_get_dns_server(s
->manager
);
153 void dns_scope_next_dns_server(DnsScope
*s
) {
156 if (s
->protocol
!= DNS_PROTOCOL_DNS
)
160 link_next_dns_server(s
->link
);
162 manager_next_dns_server(s
->manager
);
165 void dns_scope_packet_received(DnsScope
*s
, usec_t rtt
) {
168 if (rtt
<= s
->max_rtt
)
172 s
->resend_timeout
= MIN(MAX(MULTICAST_RESEND_TIMEOUT_MIN_USEC
, s
->max_rtt
* 2), MULTICAST_RESEND_TIMEOUT_MAX_USEC
);
175 void dns_scope_packet_lost(DnsScope
*s
, usec_t usec
) {
178 if (s
->resend_timeout
<= usec
)
179 s
->resend_timeout
= MIN(s
->resend_timeout
* 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC
);
182 static int dns_scope_emit_one(DnsScope
*s
, int fd
, DnsPacket
*p
) {
183 union in_addr_union addr
;
190 assert(p
->protocol
== s
->protocol
);
194 ifindex
= s
->link
->ifindex
;
196 mtu
= manager_find_mtu(s
->manager
);
198 switch (s
->protocol
) {
200 case DNS_PROTOCOL_DNS
:
203 if (DNS_PACKET_QDCOUNT(p
) > 1)
206 if (p
->size
> DNS_PACKET_UNICAST_SIZE_MAX
)
209 if (p
->size
+ UDP_PACKET_HEADER_SIZE
> mtu
)
212 r
= manager_write(s
->manager
, fd
, p
);
218 case DNS_PROTOCOL_LLMNR
:
221 if (DNS_PACKET_QDCOUNT(p
) > 1)
224 if (!ratelimit_test(&s
->ratelimit
))
229 if (family
== AF_INET
) {
230 addr
.in
= LLMNR_MULTICAST_IPV4_ADDRESS
;
231 fd
= manager_llmnr_ipv4_udp_fd(s
->manager
);
232 } else if (family
== AF_INET6
) {
233 addr
.in6
= LLMNR_MULTICAST_IPV6_ADDRESS
;
234 fd
= manager_llmnr_ipv6_udp_fd(s
->manager
);
236 return -EAFNOSUPPORT
;
240 r
= manager_send(s
->manager
, fd
, ifindex
, family
, &addr
, LLMNR_PORT
, p
);
246 case DNS_PROTOCOL_MDNS
:
249 if (!ratelimit_test(&s
->ratelimit
))
254 if (family
== AF_INET
) {
255 addr
.in
= MDNS_MULTICAST_IPV4_ADDRESS
;
256 fd
= manager_mdns_ipv4_fd(s
->manager
);
257 } else if (family
== AF_INET6
) {
258 addr
.in6
= MDNS_MULTICAST_IPV6_ADDRESS
;
259 fd
= manager_mdns_ipv6_fd(s
->manager
);
261 return -EAFNOSUPPORT
;
265 r
= manager_send(s
->manager
, fd
, ifindex
, family
, &addr
, MDNS_PORT
, p
);
272 return -EAFNOSUPPORT
;
278 int dns_scope_emit_udp(DnsScope
*s
, int fd
, DnsPacket
*p
) {
283 assert(p
->protocol
== s
->protocol
);
284 assert((s
->protocol
== DNS_PROTOCOL_DNS
) == (fd
>= 0));
287 /* If there are multiple linked packets, set the TC bit in all but the last of them */
289 assert(p
->protocol
== DNS_PROTOCOL_MDNS
);
290 dns_packet_set_flags(p
, true, true);
293 r
= dns_scope_emit_one(s
, fd
, p
);
303 static int dns_scope_socket(
307 const union in_addr_union
*address
,
311 _cleanup_close_
int fd
= -1;
312 union sockaddr_union sa
= {};
314 static const int one
= 1;
320 assert(family
== AF_UNSPEC
);
323 sa
.sa
.sa_family
= server
->family
;
324 if (server
->family
== AF_INET
) {
325 sa
.in
.sin_port
= htobe16(port
);
326 sa
.in
.sin_addr
= server
->address
.in
;
327 salen
= sizeof(sa
.in
);
328 } else if (server
->family
== AF_INET6
) {
329 sa
.in6
.sin6_port
= htobe16(port
);
330 sa
.in6
.sin6_addr
= server
->address
.in6
;
331 sa
.in6
.sin6_scope_id
= s
->link
? s
->link
->ifindex
: 0;
332 salen
= sizeof(sa
.in6
);
334 return -EAFNOSUPPORT
;
336 assert(family
!= AF_UNSPEC
);
339 sa
.sa
.sa_family
= family
;
341 if (family
== AF_INET
) {
342 sa
.in
.sin_port
= htobe16(port
);
343 sa
.in
.sin_addr
= address
->in
;
344 salen
= sizeof(sa
.in
);
345 } else if (family
== AF_INET6
) {
346 sa
.in6
.sin6_port
= htobe16(port
);
347 sa
.in6
.sin6_addr
= address
->in6
;
348 sa
.in6
.sin6_scope_id
= s
->link
? s
->link
->ifindex
: 0;
349 salen
= sizeof(sa
.in6
);
351 return -EAFNOSUPPORT
;
354 fd
= socket(sa
.sa
.sa_family
, type
|SOCK_CLOEXEC
|SOCK_NONBLOCK
, 0);
358 if (type
== SOCK_STREAM
) {
359 r
= setsockopt(fd
, IPPROTO_TCP
, TCP_NODELAY
, &one
, sizeof(one
));
365 uint32_t ifindex
= htobe32(s
->link
->ifindex
);
367 if (sa
.sa
.sa_family
== AF_INET
) {
368 r
= setsockopt(fd
, IPPROTO_IP
, IP_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
371 } else if (sa
.sa
.sa_family
== AF_INET6
) {
372 r
= setsockopt(fd
, IPPROTO_IPV6
, IPV6_UNICAST_IF
, &ifindex
, sizeof(ifindex
));
378 if (s
->protocol
== DNS_PROTOCOL_LLMNR
) {
379 /* RFC 4795, section 2.5 requires the TTL to be set to 1 */
381 if (sa
.sa
.sa_family
== AF_INET
) {
382 r
= setsockopt(fd
, IPPROTO_IP
, IP_TTL
, &one
, sizeof(one
));
385 } else if (sa
.sa
.sa_family
== AF_INET6
) {
386 r
= setsockopt(fd
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &one
, sizeof(one
));
392 r
= connect(fd
, &sa
.sa
, salen
);
393 if (r
< 0 && errno
!= EINPROGRESS
)
402 int dns_scope_socket_udp(DnsScope
*s
, DnsServer
*server
, uint16_t port
) {
403 return dns_scope_socket(s
, SOCK_DGRAM
, AF_UNSPEC
, NULL
, server
, port
);
406 int dns_scope_socket_tcp(DnsScope
*s
, int family
, const union in_addr_union
*address
, DnsServer
*server
, uint16_t port
) {
407 return dns_scope_socket(s
, SOCK_STREAM
, family
, address
, server
, port
);
410 DnsScopeMatch
dns_scope_good_domain(DnsScope
*s
, int ifindex
, uint64_t flags
, const char *domain
) {
416 /* Checks if the specified domain is something to look up on
417 * this scope. Note that this accepts non-qualified hostnames,
418 * i.e. those without any search path prefixed yet. */
420 if (ifindex
!= 0 && (!s
->link
|| s
->link
->ifindex
!= ifindex
))
423 if ((SD_RESOLVED_FLAGS_MAKE(s
->protocol
, s
->family
, 0) & flags
) == 0)
426 /* Never resolve any loopback hostname or IP address via DNS,
427 * LLMNR or mDNS. Instead, always rely on synthesized RRs for
429 if (is_localhost(domain
) ||
430 dns_name_endswith(domain
, "127.in-addr.arpa") > 0 ||
431 dns_name_equal(domain
, "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
434 /* Never respond to some of the domains listed in RFC6303 */
435 if (dns_name_endswith(domain
, "0.in-addr.arpa") > 0 ||
436 dns_name_equal(domain
, "255.255.255.255.in-addr.arpa") > 0 ||
437 dns_name_equal(domain
, "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa") > 0)
440 /* Never respond to some of the domains listed in RFC6761 */
441 if (dns_name_endswith(domain
, "invalid") > 0)
444 /* Always honour search domains for routing queries. Note that
445 * we return DNS_SCOPE_YES here, rather than just
446 * DNS_SCOPE_MAYBE, which means wildcard scopes won't be
447 * considered anymore. */
448 LIST_FOREACH(domains
, d
, dns_scope_get_search_domains(s
))
449 if (dns_name_endswith(domain
, d
->name
) > 0)
450 return DNS_SCOPE_YES
;
452 switch (s
->protocol
) {
454 case DNS_PROTOCOL_DNS
:
456 /* Exclude link-local IP ranges */
457 if (dns_name_endswith(domain
, "254.169.in-addr.arpa") == 0 &&
458 dns_name_endswith(domain
, "8.e.f.ip6.arpa") == 0 &&
459 dns_name_endswith(domain
, "9.e.f.ip6.arpa") == 0 &&
460 dns_name_endswith(domain
, "a.e.f.ip6.arpa") == 0 &&
461 dns_name_endswith(domain
, "b.e.f.ip6.arpa") == 0 &&
462 /* If networks use .local in their private setups, they are supposed to also add .local to their search
463 * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't
464 * send such queries ordinary DNS servers. */
465 dns_name_endswith(domain
, "local") == 0)
466 return DNS_SCOPE_MAYBE
;
470 case DNS_PROTOCOL_MDNS
:
471 if ((s
->family
== AF_INET
&& dns_name_endswith(domain
, "in-addr.arpa") > 0) ||
472 (s
->family
== AF_INET6
&& dns_name_endswith(domain
, "ip6.arpa") > 0) ||
473 (dns_name_endswith(domain
, "local") > 0 && /* only resolve names ending in .local via mDNS */
474 dns_name_equal(domain
, "local") == 0 && /* but not the single-label "local" name itself */
475 manager_is_own_hostname(s
->manager
, domain
) <= 0)) /* never resolve the local hostname via mDNS */
476 return DNS_SCOPE_MAYBE
;
480 case DNS_PROTOCOL_LLMNR
:
481 if ((s
->family
== AF_INET
&& dns_name_endswith(domain
, "in-addr.arpa") > 0) ||
482 (s
->family
== AF_INET6
&& dns_name_endswith(domain
, "ip6.arpa") > 0) ||
483 (dns_name_is_single_label(domain
) && /* only resolve single label names via LLMNR */
484 !is_gateway_hostname(domain
) && /* don't resolve "gateway" with LLMNR, let nss-myhostname handle this */
485 manager_is_own_hostname(s
->manager
, domain
) <= 0)) /* never resolve the local hostname via LLMNR */
486 return DNS_SCOPE_MAYBE
;
491 assert_not_reached("Unknown scope protocol");
495 int dns_scope_good_key(DnsScope
*s
, DnsResourceKey
*key
) {
499 /* Check if it makes sense to resolve the specified key on
500 * this scope. Note that this call assumes as fully qualified
501 * name, i.e. the search suffixes already appended. */
503 if (s
->protocol
== DNS_PROTOCOL_DNS
) {
505 /* On classic DNS, looking up non-address RRs is always
506 * fine. (Specifically, we want to permit looking up
507 * DNSKEY and DS records on the root and top-level
509 if (!dns_resource_key_is_address(key
))
512 /* However, we refuse to look up A and AAAA RRs on the
513 * root and single-label domains, under the assumption
514 * that those should be resolved via LLMNR or search
515 * path only, and should not be leaked onto the
517 return !(dns_name_is_single_label(DNS_RESOURCE_KEY_NAME(key
)) ||
518 dns_name_is_root(DNS_RESOURCE_KEY_NAME(key
)));
521 /* On mDNS and LLMNR, send A and AAAA queries only on the
522 * respective scopes */
524 if (s
->family
== AF_INET
&& key
->class == DNS_CLASS_IN
&& key
->type
== DNS_TYPE_AAAA
)
527 if (s
->family
== AF_INET6
&& key
->class == DNS_CLASS_IN
&& key
->type
== DNS_TYPE_A
)
533 static int dns_scope_multicast_membership(DnsScope
*s
, bool b
, struct in_addr in
, struct in6_addr in6
) {
539 if (s
->family
== AF_INET
) {
540 struct ip_mreqn mreqn
= {
542 .imr_ifindex
= s
->link
->ifindex
,
545 fd
= manager_llmnr_ipv4_udp_fd(s
->manager
);
549 /* Always first try to drop membership before we add
550 * one. This is necessary on some devices, such as
553 (void) setsockopt(fd
, IPPROTO_IP
, IP_DROP_MEMBERSHIP
, &mreqn
, sizeof(mreqn
));
555 if (setsockopt(fd
, IPPROTO_IP
, b
? IP_ADD_MEMBERSHIP
: IP_DROP_MEMBERSHIP
, &mreqn
, sizeof(mreqn
)) < 0)
558 } else if (s
->family
== AF_INET6
) {
559 struct ipv6_mreq mreq
= {
560 .ipv6mr_multiaddr
= in6
,
561 .ipv6mr_interface
= s
->link
->ifindex
,
564 fd
= manager_llmnr_ipv6_udp_fd(s
->manager
);
569 (void) setsockopt(fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
, &mreq
, sizeof(mreq
));
571 if (setsockopt(fd
, IPPROTO_IPV6
, b
? IPV6_ADD_MEMBERSHIP
: IPV6_DROP_MEMBERSHIP
, &mreq
, sizeof(mreq
)) < 0)
574 return -EAFNOSUPPORT
;
579 int dns_scope_llmnr_membership(DnsScope
*s
, bool b
) {
581 if (s
->protocol
!= DNS_PROTOCOL_LLMNR
)
584 return dns_scope_multicast_membership(s
, b
, LLMNR_MULTICAST_IPV4_ADDRESS
, LLMNR_MULTICAST_IPV6_ADDRESS
);
587 int dns_scope_mdns_membership(DnsScope
*s
, bool b
) {
589 if (s
->protocol
!= DNS_PROTOCOL_MDNS
)
592 return dns_scope_multicast_membership(s
, b
, MDNS_MULTICAST_IPV4_ADDRESS
, MDNS_MULTICAST_IPV6_ADDRESS
);
595 static int dns_scope_make_reply_packet(
605 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
612 if ((!q
|| q
->n_keys
<= 0)
613 && (!answer
|| answer
->n_rrs
<= 0)
614 && (!soa
|| soa
->n_rrs
<= 0))
617 r
= dns_packet_new(&p
, s
->protocol
, 0);
621 DNS_PACKET_HEADER(p
)->id
= id
;
622 DNS_PACKET_HEADER(p
)->flags
= htobe16(DNS_PACKET_MAKE_FLAGS(
634 for (i
= 0; i
< q
->n_keys
; i
++) {
635 r
= dns_packet_append_key(p
, q
->keys
[i
], NULL
);
640 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(q
->n_keys
);
644 for (i
= 0; i
< answer
->n_rrs
; i
++) {
645 r
= dns_packet_append_rr(p
, answer
->items
[i
].rr
, NULL
, NULL
);
650 DNS_PACKET_HEADER(p
)->ancount
= htobe16(answer
->n_rrs
);
654 for (i
= 0; i
< soa
->n_rrs
; i
++) {
655 r
= dns_packet_append_rr(p
, soa
->items
[i
].rr
, NULL
, NULL
);
660 DNS_PACKET_HEADER(p
)->arcount
= htobe16(soa
->n_rrs
);
669 static void dns_scope_verify_conflicts(DnsScope
*s
, DnsPacket
*p
) {
676 for (n
= 0; n
< p
->question
->n_keys
; n
++)
677 dns_zone_verify_conflicts(&s
->zone
, p
->question
->keys
[n
]);
679 for (n
= 0; n
< p
->answer
->n_rrs
; n
++)
680 dns_zone_verify_conflicts(&s
->zone
, p
->answer
->items
[n
].rr
->key
);
683 void dns_scope_process_query(DnsScope
*s
, DnsStream
*stream
, DnsPacket
*p
) {
684 _cleanup_(dns_packet_unrefp
) DnsPacket
*reply
= NULL
;
685 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
, *soa
= NULL
;
686 DnsResourceKey
*key
= NULL
;
687 bool tentative
= false;
693 if (p
->protocol
!= DNS_PROTOCOL_LLMNR
)
696 if (p
->ipproto
== IPPROTO_UDP
) {
697 /* Don't accept UDP queries directed to anything but
698 * the LLMNR multicast addresses. See RFC 4795,
701 if (p
->family
== AF_INET
&& !in_addr_equal(AF_INET
, &p
->destination
, (union in_addr_union
*) &LLMNR_MULTICAST_IPV4_ADDRESS
))
704 if (p
->family
== AF_INET6
&& !in_addr_equal(AF_INET6
, &p
->destination
, (union in_addr_union
*) &LLMNR_MULTICAST_IPV6_ADDRESS
))
708 r
= dns_packet_extract(p
);
710 log_debug_errno(r
, "Failed to extract resources from incoming packet: %m");
714 if (DNS_PACKET_LLMNR_C(p
)) {
715 /* Somebody notified us about a possible conflict */
716 dns_scope_verify_conflicts(s
, p
);
720 assert(p
->question
->n_keys
== 1);
721 key
= p
->question
->keys
[0];
723 r
= dns_zone_lookup(&s
->zone
, key
, &answer
, &soa
, &tentative
);
725 log_debug_errno(r
, "Failed to lookup key: %m");
732 dns_answer_order_by_scope(answer
, in_addr_is_link_local(p
->family
, &p
->sender
) > 0);
734 r
= dns_scope_make_reply_packet(s
, DNS_PACKET_ID(p
), DNS_RCODE_SUCCESS
, p
->question
, answer
, soa
, tentative
, &reply
);
736 log_debug_errno(r
, "Failed to build reply packet: %m");
741 r
= dns_stream_write_packet(stream
, reply
);
743 if (!ratelimit_test(&s
->ratelimit
))
746 if (p
->family
== AF_INET
)
747 fd
= manager_llmnr_ipv4_udp_fd(s
->manager
);
748 else if (p
->family
== AF_INET6
)
749 fd
= manager_llmnr_ipv6_udp_fd(s
->manager
);
751 log_debug("Unknown protocol");
755 log_debug_errno(fd
, "Failed to get reply socket: %m");
759 /* Note that we always immediately reply to all LLMNR
760 * requests, and do not wait any time, since we
761 * verified uniqueness for all records. Also see RFC
762 * 4795, Section 2.7 */
764 r
= manager_send(s
->manager
, fd
, p
->ifindex
, p
->family
, &p
->sender
, p
->sender_port
, reply
);
768 log_debug_errno(r
, "Failed to send reply packet: %m");
773 DnsTransaction
*dns_scope_find_transaction(DnsScope
*scope
, DnsResourceKey
*key
, bool cache_ok
) {
779 /* Try to find an ongoing transaction that is a equal to the
780 * specified question */
781 t
= hashmap_get(scope
->transactions_by_key
, key
);
785 /* Refuse reusing transactions that completed based on cached
786 * data instead of a real packet, if that's requested. */
788 IN_SET(t
->state
, DNS_TRANSACTION_SUCCESS
, DNS_TRANSACTION_RCODE_FAILURE
) &&
789 t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
795 static int dns_scope_make_conflict_packet(
797 DnsResourceRecord
*rr
,
800 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
807 r
= dns_packet_new(&p
, s
->protocol
, 0);
811 DNS_PACKET_HEADER(p
)->flags
= htobe16(DNS_PACKET_MAKE_FLAGS(
822 /* For mDNS, the transaction ID should always be 0 */
823 if (s
->protocol
!= DNS_PROTOCOL_MDNS
)
824 random_bytes(&DNS_PACKET_HEADER(p
)->id
, sizeof(uint16_t));
826 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
827 DNS_PACKET_HEADER(p
)->arcount
= htobe16(1);
829 r
= dns_packet_append_key(p
, rr
->key
, NULL
);
833 r
= dns_packet_append_rr(p
, rr
, NULL
, NULL
);
843 static int on_conflict_dispatch(sd_event_source
*es
, usec_t usec
, void *userdata
) {
844 DnsScope
*scope
= userdata
;
850 scope
->conflict_event_source
= sd_event_source_unref(scope
->conflict_event_source
);
853 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
854 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
856 rr
= ordered_hashmap_steal_first(scope
->conflict_queue
);
860 r
= dns_scope_make_conflict_packet(scope
, rr
, &p
);
862 log_error_errno(r
, "Failed to make conflict packet: %m");
866 r
= dns_scope_emit_udp(scope
, -1, p
);
868 log_debug_errno(r
, "Failed to send conflict packet: %m");
874 int dns_scope_notify_conflict(DnsScope
*scope
, DnsResourceRecord
*rr
) {
881 /* We don't send these queries immediately. Instead, we queue
882 * them, and send them after some jitter delay. */
883 r
= ordered_hashmap_ensure_allocated(&scope
->conflict_queue
, &dns_resource_key_hash_ops
);
889 /* We only place one RR per key in the conflict
890 * messages, not all of them. That should be enough to
891 * indicate where there might be a conflict */
892 r
= ordered_hashmap_put(scope
->conflict_queue
, rr
->key
, rr
);
893 if (r
== -EEXIST
|| r
== 0)
896 return log_debug_errno(r
, "Failed to queue conflicting RR: %m");
898 dns_resource_record_ref(rr
);
900 if (scope
->conflict_event_source
)
903 random_bytes(&jitter
, sizeof(jitter
));
904 jitter
%= LLMNR_JITTER_INTERVAL_USEC
;
906 r
= sd_event_add_time(scope
->manager
->event
,
907 &scope
->conflict_event_source
,
908 clock_boottime_or_monotonic(),
909 now(clock_boottime_or_monotonic()) + jitter
,
910 LLMNR_JITTER_INTERVAL_USEC
,
911 on_conflict_dispatch
, scope
);
913 return log_debug_errno(r
, "Failed to add conflict dispatch event: %m");
918 void dns_scope_check_conflicts(DnsScope
*scope
, DnsPacket
*p
) {
925 if (p
->protocol
!= DNS_PROTOCOL_LLMNR
)
928 if (DNS_PACKET_RRCOUNT(p
) <= 0)
931 if (DNS_PACKET_LLMNR_C(p
) != 0)
934 if (DNS_PACKET_LLMNR_T(p
) != 0)
937 if (manager_our_packet(scope
->manager
, p
))
940 r
= dns_packet_extract(p
);
942 log_debug_errno(r
, "Failed to extract packet: %m");
946 log_debug("Checking for conflicts...");
948 for (i
= 0; i
< p
->answer
->n_rrs
; i
++) {
950 /* Check for conflicts against the local zone. If we
951 * found one, we won't check any further */
952 r
= dns_zone_check_conflicts(&scope
->zone
, p
->answer
->items
[i
].rr
);
956 /* Check for conflicts against the local cache. If so,
957 * send out an advisory query, to inform everybody */
958 r
= dns_cache_check_conflicts(&scope
->cache
, p
->answer
->items
[i
].rr
, p
->family
, &p
->sender
);
962 dns_scope_notify_conflict(scope
, p
->answer
->items
[i
].rr
);
966 void dns_scope_dump(DnsScope
*s
, FILE *f
) {
972 fputs("[Scope protocol=", f
);
973 fputs(dns_protocol_to_string(s
->protocol
), f
);
976 fputs(" interface=", f
);
977 fputs(s
->link
->name
, f
);
980 if (s
->family
!= AF_UNSPEC
) {
981 fputs(" family=", f
);
982 fputs(af_to_name(s
->family
), f
);
987 if (!dns_zone_is_empty(&s
->zone
)) {
989 dns_zone_dump(&s
->zone
, f
);
992 if (!dns_cache_is_empty(&s
->cache
)) {
993 fputs("CACHE:\n", f
);
994 dns_cache_dump(&s
->cache
, f
);
998 DnsSearchDomain
*dns_scope_get_search_domains(DnsScope
*s
) {
1001 if (s
->protocol
!= DNS_PROTOCOL_DNS
)
1005 return s
->link
->search_domains
;
1007 return s
->manager
->search_domains
;
1010 bool dns_scope_name_needs_search_domain(DnsScope
*s
, const char *name
) {
1013 if (s
->protocol
!= DNS_PROTOCOL_DNS
)
1016 return dns_name_is_single_label(name
);