1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
4 #include <netinet/in.h>
12 #include "alloc-util.h"
13 #include "bus-polkit.h"
14 #include "dirent-util.h"
15 #include "dns-domain.h"
16 #include "event-util.h"
19 #include "hostname-util.h"
22 #include "missing_network.h"
23 #include "missing_socket.h"
24 #include "netlink-util.h"
25 #include "ordered-set.h"
26 #include "parse-util.h"
27 #include "random-util.h"
28 #include "resolved-bus.h"
29 #include "resolved-conf.h"
30 #include "resolved-dns-stub.h"
31 #include "resolved-dnssd.h"
32 #include "resolved-etc-hosts.h"
33 #include "resolved-llmnr.h"
34 #include "resolved-manager.h"
35 #include "resolved-mdns.h"
36 #include "resolved-resolv-conf.h"
37 #include "resolved-util.h"
38 #include "resolved-varlink.h"
39 #include "socket-util.h"
40 #include "string-table.h"
41 #include "string-util.h"
44 #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
46 static int manager_process_link(sd_netlink
*rtnl
, sd_netlink_message
*mm
, void *userdata
) {
47 Manager
*m
= ASSERT_PTR(userdata
);
55 r
= sd_netlink_message_get_type(mm
, &type
);
59 r
= sd_rtnl_message_link_get_ifindex(mm
, &ifindex
);
63 l
= hashmap_get(m
->links
, INT_TO_PTR(ifindex
));
71 r
= link_new(m
, &l
, ifindex
);
76 r
= link_process_rtnl(l
, mm
);
85 log_debug("Found new link %i/%s", ifindex
, l
->ifname
);
92 log_debug("Removing link %i/%s", l
->ifindex
, l
->ifname
);
103 log_warning_errno(r
, "Failed to process RTNL link message: %m");
107 static int manager_process_address(sd_netlink
*rtnl
, sd_netlink_message
*mm
, void *userdata
) {
108 Manager
*m
= ASSERT_PTR(userdata
);
109 union in_addr_union address
;
111 int r
, ifindex
, family
;
118 r
= sd_netlink_message_get_type(mm
, &type
);
122 r
= sd_rtnl_message_addr_get_ifindex(mm
, &ifindex
);
126 l
= hashmap_get(m
->links
, INT_TO_PTR(ifindex
));
130 r
= sd_rtnl_message_addr_get_family(mm
, &family
);
137 r
= sd_netlink_message_read_in_addr(mm
, IFA_LOCAL
, &address
.in
);
139 r
= sd_netlink_message_read_in_addr(mm
, IFA_ADDRESS
, &address
.in
);
147 r
= sd_netlink_message_read_in6_addr(mm
, IFA_LOCAL
, &address
.in6
);
149 r
= sd_netlink_message_read_in6_addr(mm
, IFA_ADDRESS
, &address
.in6
);
160 a
= link_find_address(l
, family
, &address
);
167 r
= link_address_new(l
, &a
, family
, &address
);
172 r
= link_address_update_rtnl(a
, mm
);
179 link_address_free(a
);
186 log_warning_errno(r
, "Failed to process RTNL address message: %m");
190 static int manager_rtnl_listen(Manager
*m
) {
191 _cleanup_(sd_netlink_message_unrefp
) sd_netlink_message
*req
= NULL
, *reply
= NULL
;
192 sd_netlink_message
*i
;
197 /* First, subscribe to interfaces coming and going */
198 r
= sd_netlink_open(&m
->rtnl
);
202 r
= sd_netlink_attach_event(m
->rtnl
, m
->event
, SD_EVENT_PRIORITY_IMPORTANT
);
206 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_NEWLINK
, manager_process_link
, NULL
, m
, "resolve-NEWLINK");
210 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_DELLINK
, manager_process_link
, NULL
, m
, "resolve-DELLINK");
214 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_NEWADDR
, manager_process_address
, NULL
, m
, "resolve-NEWADDR");
218 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_DELADDR
, manager_process_address
, NULL
, m
, "resolve-DELADDR");
222 /* Then, enumerate all links */
223 r
= sd_rtnl_message_new_link(m
->rtnl
, &req
, RTM_GETLINK
, 0);
227 r
= sd_netlink_message_set_request_dump(req
, true);
231 r
= sd_netlink_call(m
->rtnl
, req
, 0, &reply
);
235 for (i
= reply
; i
; i
= sd_netlink_message_next(i
)) {
236 r
= manager_process_link(m
->rtnl
, i
, m
);
241 req
= sd_netlink_message_unref(req
);
242 reply
= sd_netlink_message_unref(reply
);
244 /* Finally, enumerate all addresses, too */
245 r
= sd_rtnl_message_new_addr(m
->rtnl
, &req
, RTM_GETADDR
, 0, AF_UNSPEC
);
249 r
= sd_netlink_message_set_request_dump(req
, true);
253 r
= sd_netlink_call(m
->rtnl
, req
, 0, &reply
);
257 for (i
= reply
; i
; i
= sd_netlink_message_next(i
)) {
258 r
= manager_process_address(m
->rtnl
, i
, m
);
266 static int on_network_event(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
267 Manager
*m
= ASSERT_PTR(userdata
);
271 sd_network_monitor_flush(m
->network_monitor
);
273 HASHMAP_FOREACH(l
, m
->links
) {
276 log_warning_errno(r
, "Failed to update monitor information for %i: %m", l
->ifindex
);
279 (void) manager_write_resolv_conf(m
);
280 (void) manager_send_changed(m
, "DNS");
285 static int manager_network_monitor_listen(Manager
*m
) {
290 r
= sd_network_monitor_new(&m
->network_monitor
, NULL
);
294 fd
= sd_network_monitor_get_fd(m
->network_monitor
);
298 events
= sd_network_monitor_get_events(m
->network_monitor
);
302 r
= sd_event_add_io(m
->event
, &m
->network_event_source
, fd
, events
, &on_network_event
, m
);
306 r
= sd_event_source_set_priority(m
->network_event_source
, SD_EVENT_PRIORITY_IMPORTANT
+5);
310 (void) sd_event_source_set_description(m
->network_event_source
, "network-monitor");
315 static int manager_clock_change_listen(Manager
*m
);
317 static int on_clock_change(sd_event_source
*source
, int fd
, uint32_t revents
, void *userdata
) {
318 Manager
*m
= ASSERT_PTR(userdata
);
320 /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
321 * the system clock into consideration, and if the clock changes the old validations might have been
322 * wrong. Let's redo all validation with the new, correct time.
324 * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
325 * we might be connected to a different network now without this being visible in a dropped link
328 log_info("Clock change detected. Flushing caches.");
329 manager_flush_caches(m
, LOG_DEBUG
/* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
331 /* The clock change timerfd is unusable after it triggered once, create a new one. */
332 return manager_clock_change_listen(m
);
335 static int manager_clock_change_listen(Manager
*m
) {
340 m
->clock_change_event_source
= sd_event_source_disable_unref(m
->clock_change_event_source
);
342 r
= event_add_time_change(m
->event
, &m
->clock_change_event_source
, on_clock_change
, m
);
344 return log_error_errno(r
, "Failed to create clock change event source: %m");
349 static int determine_hostnames(char **full_hostname
, char **llmnr_hostname
, char **mdns_hostname
) {
350 _cleanup_free_
char *h
= NULL
, *n
= NULL
;
353 assert(full_hostname
);
354 assert(llmnr_hostname
);
355 assert(mdns_hostname
);
357 r
= resolve_system_hostname(&h
, &n
);
361 r
= dns_name_concat(n
, "local", 0, mdns_hostname
);
363 return log_error_errno(r
, "Failed to determine mDNS hostname: %m");
365 *llmnr_hostname
= TAKE_PTR(n
);
366 *full_hostname
= TAKE_PTR(h
);
371 static char* fallback_hostname(void) {
373 /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
374 * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
377 _cleanup_free_
char *n
= get_default_hostname();
382 return strdup("linux");
387 static int make_fallback_hostnames(char **full_hostname
, char **llmnr_hostname
, char **mdns_hostname
) {
388 _cleanup_free_
char *h
= NULL
, *n
= NULL
, *m
= NULL
;
389 char label
[DNS_LABEL_MAX
];
393 assert(full_hostname
);
394 assert(llmnr_hostname
);
395 assert(mdns_hostname
);
397 p
= h
= fallback_hostname();
401 r
= dns_label_unescape(&p
, label
, sizeof label
, 0);
403 return log_error_errno(r
, "Failed to unescape fallback hostname: %m");
405 assert(r
> 0); /* The fallback hostname must have at least one label */
407 r
= dns_label_escape_new(label
, r
, &n
);
409 return log_error_errno(r
, "Failed to escape fallback hostname: %m");
411 r
= dns_name_concat(n
, "local", 0, &m
);
413 return log_error_errno(r
, "Failed to concatenate mDNS hostname: %m");
415 *llmnr_hostname
= TAKE_PTR(n
);
416 *mdns_hostname
= TAKE_PTR(m
);
417 *full_hostname
= TAKE_PTR(h
);
422 static int on_hostname_change(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
423 _cleanup_free_
char *full_hostname
= NULL
, *llmnr_hostname
= NULL
, *mdns_hostname
= NULL
;
424 Manager
*m
= ASSERT_PTR(userdata
);
425 bool llmnr_hostname_changed
;
428 r
= determine_hostnames(&full_hostname
, &llmnr_hostname
, &mdns_hostname
);
430 log_warning_errno(r
, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
431 return 0; /* ignore invalid hostnames */
434 llmnr_hostname_changed
= !streq(llmnr_hostname
, m
->llmnr_hostname
);
435 if (streq(full_hostname
, m
->full_hostname
) &&
436 !llmnr_hostname_changed
&&
437 streq(mdns_hostname
, m
->mdns_hostname
))
440 log_info("System hostname changed to '%s'.", full_hostname
);
442 free_and_replace(m
->full_hostname
, full_hostname
);
443 free_and_replace(m
->llmnr_hostname
, llmnr_hostname
);
444 free_and_replace(m
->mdns_hostname
, mdns_hostname
);
446 manager_refresh_rrs(m
);
447 (void) manager_send_changed(m
, "LLMNRHostname");
452 static int manager_watch_hostname(Manager
*m
) {
457 m
->hostname_fd
= open("/proc/sys/kernel/hostname",
458 O_RDONLY
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
459 if (m
->hostname_fd
< 0) {
460 log_warning_errno(errno
, "Failed to watch hostname: %m");
464 r
= sd_event_add_io(m
->event
, &m
->hostname_event_source
, m
->hostname_fd
, 0, on_hostname_change
, m
);
467 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
468 m
->hostname_fd
= safe_close(m
->hostname_fd
);
470 return log_error_errno(r
, "Failed to add hostname event source: %m");
473 (void) sd_event_source_set_description(m
->hostname_event_source
, "hostname");
475 r
= determine_hostnames(&m
->full_hostname
, &m
->llmnr_hostname
, &m
->mdns_hostname
);
477 _cleanup_free_
char *d
= NULL
;
479 d
= fallback_hostname();
483 log_info("Defaulting to hostname '%s'.", d
);
485 r
= make_fallback_hostnames(&m
->full_hostname
, &m
->llmnr_hostname
, &m
->mdns_hostname
);
489 log_info("Using system hostname '%s'.", m
->full_hostname
);
494 static int manager_sigusr1(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
495 _cleanup_free_
char *buffer
= NULL
;
496 _cleanup_fclose_
FILE *f
= NULL
;
497 Manager
*m
= ASSERT_PTR(userdata
);
504 f
= open_memstream_unlocked(&buffer
, &size
);
508 LIST_FOREACH(scopes
, scope
, m
->dns_scopes
)
509 dns_scope_dump(scope
, f
);
511 LIST_FOREACH(servers
, server
, m
->dns_servers
)
512 dns_server_dump(server
, f
);
513 LIST_FOREACH(servers
, server
, m
->fallback_dns_servers
)
514 dns_server_dump(server
, f
);
515 HASHMAP_FOREACH(l
, m
->links
)
516 LIST_FOREACH(servers
, server
, l
->dns_servers
)
517 dns_server_dump(server
, f
);
519 if (fflush_and_check(f
) < 0)
522 log_dump(LOG_INFO
, buffer
);
526 static int manager_sigusr2(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
527 Manager
*m
= ASSERT_PTR(userdata
);
532 manager_flush_caches(m
, LOG_INFO
);
537 static int manager_sigrtmin1(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
538 Manager
*m
= ASSERT_PTR(userdata
);
543 manager_reset_server_features(m
);
547 int manager_new(Manager
**ret
) {
548 _cleanup_(manager_freep
) Manager
*m
= NULL
;
558 .llmnr_ipv4_udp_fd
= -1,
559 .llmnr_ipv6_udp_fd
= -1,
560 .llmnr_ipv4_tcp_fd
= -1,
561 .llmnr_ipv6_tcp_fd
= -1,
566 .llmnr_support
= DEFAULT_LLMNR_MODE
,
567 .mdns_support
= DEFAULT_MDNS_MODE
,
568 .dnssec_mode
= DEFAULT_DNSSEC_MODE
,
569 .dns_over_tls_mode
= DEFAULT_DNS_OVER_TLS_MODE
,
570 .enable_cache
= DNS_CACHE_MODE_YES
,
571 .dns_stub_listener_mode
= DNS_STUB_LISTENER_YES
,
572 .read_resolv_conf
= true,
573 .need_builtin_fallbacks
= true,
574 .etc_hosts_last
= USEC_INFINITY
,
575 .read_etc_hosts
= true,
578 r
= dns_trust_anchor_load(&m
->trust_anchor
);
582 r
= manager_parse_config_file(m
);
584 log_warning_errno(r
, "Failed to parse configuration file: %m");
586 #if ENABLE_DNS_OVER_TLS
587 r
= dnstls_manager_init(m
);
592 r
= sd_event_default(&m
->event
);
596 (void) sd_event_add_signal(m
->event
, NULL
, SIGTERM
, NULL
, NULL
);
597 (void) sd_event_add_signal(m
->event
, NULL
, SIGINT
, NULL
, NULL
);
599 (void) sd_event_set_watchdog(m
->event
, true);
601 r
= manager_watch_hostname(m
);
607 log_warning_errno(r
, "Failed to load DNS-SD configuration files: %m");
609 r
= dns_scope_new(m
, &m
->unicast_scope
, NULL
, DNS_PROTOCOL_DNS
, AF_UNSPEC
);
613 r
= manager_network_monitor_listen(m
);
617 r
= manager_rtnl_listen(m
);
621 r
= manager_clock_change_listen(m
);
625 r
= manager_connect_bus(m
);
629 (void) sd_event_add_signal(m
->event
, &m
->sigusr1_event_source
, SIGUSR1
, manager_sigusr1
, m
);
630 (void) sd_event_add_signal(m
->event
, &m
->sigusr2_event_source
, SIGUSR2
, manager_sigusr2
, m
);
631 (void) sd_event_add_signal(m
->event
, &m
->sigrtmin1_event_source
, SIGRTMIN
+1, manager_sigrtmin1
, m
);
633 manager_cleanup_saved_user(m
);
640 int manager_start(Manager
*m
) {
645 r
= manager_dns_stub_start(m
);
649 r
= manager_varlink_init(m
);
656 Manager
*manager_free(Manager
*m
) {
663 dns_server_unlink_all(m
->dns_servers
);
664 dns_server_unlink_all(m
->fallback_dns_servers
);
665 dns_search_domain_unlink_all(m
->search_domains
);
667 while ((l
= hashmap_first(m
->links
)))
670 while (m
->dns_queries
)
671 dns_query_free(m
->dns_queries
);
673 m
->stub_queries_by_packet
= hashmap_free(m
->stub_queries_by_packet
);
675 dns_scope_free(m
->unicast_scope
);
677 /* At this point only orphaned streams should remain. All others should have been freed already by their
679 while (m
->dns_streams
)
680 dns_stream_unref(m
->dns_streams
);
682 #if ENABLE_DNS_OVER_TLS
683 dnstls_manager_free(m
);
686 hashmap_free(m
->links
);
687 hashmap_free(m
->dns_transactions
);
689 sd_event_source_unref(m
->network_event_source
);
690 sd_network_monitor_unref(m
->network_monitor
);
692 sd_netlink_unref(m
->rtnl
);
693 sd_event_source_unref(m
->rtnl_event_source
);
694 sd_event_source_unref(m
->clock_change_event_source
);
696 manager_llmnr_stop(m
);
697 manager_mdns_stop(m
);
698 manager_dns_stub_stop(m
);
699 manager_varlink_done(m
);
701 manager_socket_graveyard_clear(m
);
703 ordered_set_free(m
->dns_extra_stub_listeners
);
705 bus_verify_polkit_async_registry_free(m
->polkit_registry
);
707 sd_bus_flush_close_unref(m
->bus
);
709 sd_event_source_unref(m
->sigusr1_event_source
);
710 sd_event_source_unref(m
->sigusr2_event_source
);
711 sd_event_source_unref(m
->sigrtmin1_event_source
);
713 dns_resource_key_unref(m
->llmnr_host_ipv4_key
);
714 dns_resource_key_unref(m
->llmnr_host_ipv6_key
);
715 dns_resource_key_unref(m
->mdns_host_ipv4_key
);
716 dns_resource_key_unref(m
->mdns_host_ipv6_key
);
718 sd_event_source_unref(m
->hostname_event_source
);
719 safe_close(m
->hostname_fd
);
721 sd_event_unref(m
->event
);
723 free(m
->full_hostname
);
724 free(m
->llmnr_hostname
);
725 free(m
->mdns_hostname
);
727 while ((s
= hashmap_first(m
->dnssd_services
)))
728 dnssd_service_free(s
);
729 hashmap_free(m
->dnssd_services
);
731 dns_trust_anchor_flush(&m
->trust_anchor
);
732 manager_etc_hosts_flush(m
);
737 int manager_recv(Manager
*m
, int fd
, DnsProtocol protocol
, DnsPacket
**ret
) {
738 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
739 CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
740 + CMSG_SPACE(int) /* ttl/hoplimit */
741 + EXTRA_CMSG_SPACE
/* kernel appears to require extra buffer space */) control
;
742 union sockaddr_union sa
;
746 .msg_namelen
= sizeof(sa
),
749 .msg_control
= &control
,
750 .msg_controllen
= sizeof(control
),
752 struct cmsghdr
*cmsg
;
760 ms
= next_datagram_size_fd(fd
);
764 r
= dns_packet_new(&p
, protocol
, ms
, DNS_PACKET_SIZE_MAX
);
768 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->allocated
);
770 l
= recvmsg_safe(fd
, &mh
, 0);
772 if (ERRNO_IS_TRANSIENT(l
))
779 assert(!(mh
.msg_flags
& MSG_TRUNC
));
781 p
->size
= (size_t) l
;
783 p
->family
= sa
.sa
.sa_family
;
784 p
->ipproto
= IPPROTO_UDP
;
785 if (p
->family
== AF_INET
) {
786 p
->sender
.in
= sa
.in
.sin_addr
;
787 p
->sender_port
= be16toh(sa
.in
.sin_port
);
788 } else if (p
->family
== AF_INET6
) {
789 p
->sender
.in6
= sa
.in6
.sin6_addr
;
790 p
->sender_port
= be16toh(sa
.in6
.sin6_port
);
791 p
->ifindex
= sa
.in6
.sin6_scope_id
;
793 return -EAFNOSUPPORT
;
795 p
->timestamp
= now(CLOCK_BOOTTIME
);
797 CMSG_FOREACH(cmsg
, &mh
) {
799 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
800 assert(p
->family
== AF_INET6
);
802 switch (cmsg
->cmsg_type
) {
805 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
808 p
->ifindex
= i
->ipi6_ifindex
;
810 p
->destination
.in6
= i
->ipi6_addr
;
815 p
->ttl
= *(int *) CMSG_DATA(cmsg
);
818 case IPV6_RECVFRAGSIZE
:
819 p
->fragsize
= *(int *) CMSG_DATA(cmsg
);
822 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
823 assert(p
->family
== AF_INET
);
825 switch (cmsg
->cmsg_type
) {
828 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
831 p
->ifindex
= i
->ipi_ifindex
;
833 p
->destination
.in
= i
->ipi_addr
;
838 p
->ttl
= *(int *) CMSG_DATA(cmsg
);
841 case IP_RECVFRAGSIZE
:
842 p
->fragsize
= *(int *) CMSG_DATA(cmsg
);
848 /* The Linux kernel sets the interface index to the loopback
849 * device if the packet came from the local host since it
850 * avoids the routing table in such a case. Let's unset the
851 * interface index in such a case. */
852 if (p
->ifindex
== LOOPBACK_IFINDEX
)
855 if (protocol
!= DNS_PROTOCOL_DNS
) {
856 /* If we don't know the interface index still, we look for the
857 * first local interface with a matching address. Yuck! */
859 p
->ifindex
= manager_find_ifindex(m
, p
->family
, &p
->destination
);
862 log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
863 dns_protocol_to_string(protocol
), p
->size
, p
->ifindex
, p
->ttl
, p
->fragsize
,
864 IN_ADDR_TO_STRING(p
->family
, &p
->sender
),
865 IN_ADDR_TO_STRING(p
->family
, &p
->destination
));
871 static int sendmsg_loop(int fd
, struct msghdr
*mh
, int flags
) {
878 if (sendmsg(fd
, mh
, flags
) >= 0)
887 r
= fd_wait_for_event(fd
, POLLOUT
, SEND_TIMEOUT_USEC
);
895 static int write_loop(int fd
, void *message
, size_t length
) {
902 if (write(fd
, message
, length
) >= 0)
911 r
= fd_wait_for_event(fd
, POLLOUT
, SEND_TIMEOUT_USEC
);
919 int manager_write(Manager
*m
, int fd
, DnsPacket
*p
) {
922 log_debug("Sending %s%s packet with id %" PRIu16
" of size %zu.",
923 DNS_PACKET_TC(p
) ? "truncated (!) " : "",
924 DNS_PACKET_QR(p
) ? "response" : "query",
928 r
= write_loop(fd
, DNS_PACKET_DATA(p
), p
->size
);
935 static int manager_ipv4_send(
939 const struct in_addr
*destination
,
941 const struct in_addr
*source
,
944 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo
))) control
= {};
945 union sockaddr_union sa
;
951 .msg_namelen
= sizeof(sa
.in
),
960 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->size
);
962 sa
= (union sockaddr_union
) {
963 .in
.sin_family
= AF_INET
,
964 .in
.sin_addr
= *destination
,
965 .in
.sin_port
= htobe16(port
),
969 struct cmsghdr
*cmsg
;
970 struct in_pktinfo
*pi
;
972 mh
.msg_control
= &control
;
973 mh
.msg_controllen
= sizeof(control
);
975 cmsg
= CMSG_FIRSTHDR(&mh
);
976 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct in_pktinfo
));
977 cmsg
->cmsg_level
= IPPROTO_IP
;
978 cmsg
->cmsg_type
= IP_PKTINFO
;
980 pi
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
981 pi
->ipi_ifindex
= ifindex
;
984 pi
->ipi_spec_dst
= *source
;
987 return sendmsg_loop(fd
, &mh
, 0);
990 static int manager_ipv6_send(
994 const struct in6_addr
*destination
,
996 const struct in6_addr
*source
,
999 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo
))) control
= {};
1000 union sockaddr_union sa
;
1002 struct msghdr mh
= {
1006 .msg_namelen
= sizeof(sa
.in6
),
1011 assert(destination
);
1015 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->size
);
1017 sa
= (union sockaddr_union
) {
1018 .in6
.sin6_family
= AF_INET6
,
1019 .in6
.sin6_addr
= *destination
,
1020 .in6
.sin6_port
= htobe16(port
),
1021 .in6
.sin6_scope_id
= ifindex
,
1025 struct cmsghdr
*cmsg
;
1026 struct in6_pktinfo
*pi
;
1028 mh
.msg_control
= &control
;
1029 mh
.msg_controllen
= sizeof(control
);
1031 cmsg
= CMSG_FIRSTHDR(&mh
);
1032 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
1033 cmsg
->cmsg_level
= IPPROTO_IPV6
;
1034 cmsg
->cmsg_type
= IPV6_PKTINFO
;
1036 pi
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
1037 pi
->ipi6_ifindex
= ifindex
;
1040 pi
->ipi6_addr
= *source
;
1043 return sendmsg_loop(fd
, &mh
, 0);
1046 int send_dns_notification(Manager
*m
, DnsAnswer
*answer
, const char *query_name
) {
1047 _cleanup_free_
char *normalized
= NULL
;
1048 DnsResourceRecord
*rr
;
1050 _cleanup_(json_variant_unrefp
) JsonVariant
*array
= NULL
;
1051 Varlink
*connection
;
1055 if (set_isempty(m
->varlink_subscription
))
1058 DNS_ANSWER_FOREACH_IFINDEX(rr
, ifindex
, answer
) {
1059 _cleanup_(json_variant_unrefp
) JsonVariant
*entry
= NULL
;
1061 if (rr
->key
->type
== DNS_TYPE_A
) {
1062 struct in_addr
*addr
= &rr
->a
.in_addr
;
1063 r
= json_build(&entry
,
1064 JSON_BUILD_OBJECT(JSON_BUILD_PAIR_CONDITION(ifindex
> 0, "ifindex", JSON_BUILD_INTEGER(ifindex
)),
1065 JSON_BUILD_PAIR_INTEGER("family", AF_INET
),
1066 JSON_BUILD_PAIR_IN4_ADDR("address", addr
),
1067 JSON_BUILD_PAIR_STRING("type", "A")));
1068 } else if (rr
->key
->type
== DNS_TYPE_AAAA
) {
1069 struct in6_addr
*addr6
= &rr
->aaaa
.in6_addr
;
1070 r
= json_build(&entry
,
1071 JSON_BUILD_OBJECT(JSON_BUILD_PAIR_CONDITION(ifindex
> 0, "ifindex", JSON_BUILD_INTEGER(ifindex
)),
1072 JSON_BUILD_PAIR_INTEGER("family", AF_INET6
),
1073 JSON_BUILD_PAIR_IN6_ADDR("address", addr6
),
1074 JSON_BUILD_PAIR_STRING("type", "AAAA")));
1078 log_debug_errno(r
, "Failed to build json object: %m");
1082 r
= json_variant_append_array(&array
, entry
);
1084 return log_debug_errno(r
, "Failed to append notification entry to array: %m");
1087 if (json_variant_is_blank_object(array
))
1090 r
= dns_name_normalize(query_name
, 0, &normalized
);
1092 return log_debug_errno(r
, "Failed to normalize query name: %m");
1094 SET_FOREACH(connection
, m
->varlink_subscription
) {
1095 r
= varlink_notifyb(connection
,
1096 JSON_BUILD_OBJECT(JSON_BUILD_PAIR("addresses",
1097 JSON_BUILD_VARIANT(array
)),
1098 JSON_BUILD_PAIR("name", JSON_BUILD_STRING(normalized
))));
1100 log_debug_errno(r
, "Failed to send notification, ignoring: %m");
1110 const union in_addr_union
*destination
,
1112 const union in_addr_union
*source
,
1117 assert(destination
);
1121 log_debug("Sending %s%s packet with id %" PRIu16
" on interface %i/%s of size %zu.",
1122 DNS_PACKET_TC(p
) ? "truncated (!) " : "",
1123 DNS_PACKET_QR(p
) ? "response" : "query",
1125 ifindex
, af_to_name(family
),
1128 if (family
== AF_INET
)
1129 return manager_ipv4_send(m
, fd
, ifindex
, &destination
->in
, port
, source
? &source
->in
: NULL
, p
);
1130 if (family
== AF_INET6
)
1131 return manager_ipv6_send(m
, fd
, ifindex
, &destination
->in6
, port
, source
? &source
->in6
: NULL
, p
);
1133 return -EAFNOSUPPORT
;
1136 uint32_t manager_find_mtu(Manager
*m
) {
1140 /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1141 * works on all interfaces we know of that have an IP address associated */
1143 HASHMAP_FOREACH(l
, m
->links
) {
1144 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1148 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1149 * let's ignore this link. */
1150 if (l
->mtu
< MIN(UDP4_PACKET_HEADER_SIZE
+ DNS_PACKET_HEADER_SIZE
,
1151 UDP6_PACKET_HEADER_SIZE
+ DNS_PACKET_HEADER_SIZE
))
1154 if (mtu
<= 0 || l
->mtu
< mtu
)
1158 if (mtu
== 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1164 int manager_find_ifindex(Manager
*m
, int family
, const union in_addr_union
*in_addr
) {
1169 if (!IN_SET(family
, AF_INET
, AF_INET6
))
1175 a
= manager_find_link_address(m
, family
, in_addr
);
1177 return a
->link
->ifindex
;
1182 void manager_refresh_rrs(Manager
*m
) {
1188 m
->llmnr_host_ipv4_key
= dns_resource_key_unref(m
->llmnr_host_ipv4_key
);
1189 m
->llmnr_host_ipv6_key
= dns_resource_key_unref(m
->llmnr_host_ipv6_key
);
1190 m
->mdns_host_ipv4_key
= dns_resource_key_unref(m
->mdns_host_ipv4_key
);
1191 m
->mdns_host_ipv6_key
= dns_resource_key_unref(m
->mdns_host_ipv6_key
);
1193 HASHMAP_FOREACH(l
, m
->links
)
1194 link_add_rrs(l
, true);
1196 if (m
->mdns_support
== RESOLVE_SUPPORT_YES
)
1197 HASHMAP_FOREACH(s
, m
->dnssd_services
)
1198 if (dnssd_update_rrs(s
) < 0)
1199 log_warning("Failed to refresh DNS-SD service '%s'", s
->name
);
1201 HASHMAP_FOREACH(l
, m
->links
)
1202 link_add_rrs(l
, false);
1205 static int manager_next_random_name(const char *old
, char **ret_new
) {
1214 if (!ascii_isdigit(p
[-1]))
1220 if (*p
== 0 || safe_atou64(p
, &u
) < 0 || u
<= 0)
1223 /* Add a random number to the old value. This way we can avoid
1224 * that two hosts pick the same hostname, win on IPv4 and lose
1225 * on IPv6 (or vice versa), and pick the same hostname
1226 * replacement hostname, ad infinitum. We still want the
1227 * numbers to go up monotonically, hence we just add a random
1230 random_bytes(&a
, sizeof(a
));
1233 if (asprintf(&n
, "%.*s%" PRIu64
, (int) (p
- old
), old
, u
) < 0)
1241 int manager_next_hostname(Manager
*m
) {
1242 _cleanup_free_
char *h
= NULL
, *k
= NULL
;
1247 r
= manager_next_random_name(m
->llmnr_hostname
, &h
);
1251 r
= dns_name_concat(h
, "local", 0, &k
);
1255 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m
->llmnr_hostname
, h
);
1257 free_and_replace(m
->llmnr_hostname
, h
);
1258 free_and_replace(m
->mdns_hostname
, k
);
1260 manager_refresh_rrs(m
);
1261 (void) manager_send_changed(m
, "LLMNRHostname");
1266 LinkAddress
* manager_find_link_address(Manager
*m
, int family
, const union in_addr_union
*in_addr
) {
1271 if (!IN_SET(family
, AF_INET
, AF_INET6
))
1277 HASHMAP_FOREACH(l
, m
->links
) {
1280 a
= link_find_address(l
, family
, in_addr
);
1288 bool manager_packet_from_local_address(Manager
*m
, DnsPacket
*p
) {
1292 /* Let's see if this packet comes from an IP address we have on any local interface */
1294 return !!manager_find_link_address(m
, p
->family
, &p
->sender
);
1297 bool manager_packet_from_our_transaction(Manager
*m
, DnsPacket
*p
) {
1303 /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1304 * one we just got. If so, it's almost definitely a packet loop of some kind. */
1306 t
= hashmap_get(m
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
1310 return t
->sent
&& dns_packet_equal(t
->sent
, p
);
1313 DnsScope
* manager_find_scope(Manager
*m
, DnsPacket
*p
) {
1319 l
= hashmap_get(m
->links
, INT_TO_PTR(p
->ifindex
));
1323 switch (p
->protocol
) {
1324 case DNS_PROTOCOL_LLMNR
:
1325 if (p
->family
== AF_INET
)
1326 return l
->llmnr_ipv4_scope
;
1327 else if (p
->family
== AF_INET6
)
1328 return l
->llmnr_ipv6_scope
;
1332 case DNS_PROTOCOL_MDNS
:
1333 if (p
->family
== AF_INET
)
1334 return l
->mdns_ipv4_scope
;
1335 else if (p
->family
== AF_INET6
)
1336 return l
->mdns_ipv6_scope
;
1347 void manager_verify_all(Manager
*m
) {
1350 LIST_FOREACH(scopes
, s
, m
->dns_scopes
)
1351 dns_zone_verify_all(&s
->zone
);
1354 int manager_is_own_hostname(Manager
*m
, const char *name
) {
1360 if (m
->llmnr_hostname
) {
1361 r
= dns_name_equal(name
, m
->llmnr_hostname
);
1366 if (m
->mdns_hostname
) {
1367 r
= dns_name_equal(name
, m
->mdns_hostname
);
1372 if (m
->full_hostname
)
1373 return dns_name_equal(name
, m
->full_hostname
);
1378 int manager_compile_dns_servers(Manager
*m
, OrderedSet
**dns
) {
1385 r
= ordered_set_ensure_allocated(dns
, &dns_server_hash_ops
);
1389 /* First add the system-wide servers and domains */
1390 LIST_FOREACH(servers
, s
, m
->dns_servers
) {
1391 r
= ordered_set_put(*dns
, s
);
1398 /* Then, add the per-link servers */
1399 HASHMAP_FOREACH(l
, m
->links
) {
1400 LIST_FOREACH(servers
, s
, l
->dns_servers
) {
1401 r
= ordered_set_put(*dns
, s
);
1409 /* If we found nothing, add the fallback servers */
1410 if (ordered_set_isempty(*dns
)) {
1411 LIST_FOREACH(servers
, s
, m
->fallback_dns_servers
) {
1412 r
= ordered_set_put(*dns
, s
);
1423 /* filter_route is a tri-state:
1425 * = 0 or false: return only domains which should be used for searching
1426 * > 0 or true: return only domains which are for routing only
1428 int manager_compile_search_domains(Manager
*m
, OrderedSet
**domains
, int filter_route
) {
1435 r
= ordered_set_ensure_allocated(domains
, &dns_name_hash_ops
);
1439 LIST_FOREACH(domains
, d
, m
->search_domains
) {
1441 if (filter_route
>= 0 &&
1442 d
->route_only
!= !!filter_route
)
1445 r
= ordered_set_put(*domains
, d
->name
);
1452 HASHMAP_FOREACH(l
, m
->links
) {
1454 LIST_FOREACH(domains
, d
, l
->search_domains
) {
1456 if (filter_route
>= 0 &&
1457 d
->route_only
!= !!filter_route
)
1460 r
= ordered_set_put(*domains
, d
->name
);
1471 DnssecMode
manager_get_dnssec_mode(Manager
*m
) {
1474 if (m
->dnssec_mode
!= _DNSSEC_MODE_INVALID
)
1475 return m
->dnssec_mode
;
1480 bool manager_dnssec_supported(Manager
*m
) {
1486 if (manager_get_dnssec_mode(m
) == DNSSEC_NO
)
1489 server
= manager_get_dns_server(m
);
1490 if (server
&& !dns_server_dnssec_supported(server
))
1493 HASHMAP_FOREACH(l
, m
->links
)
1494 if (!link_dnssec_supported(l
))
1500 DnsOverTlsMode
manager_get_dns_over_tls_mode(Manager
*m
) {
1503 if (m
->dns_over_tls_mode
!= _DNS_OVER_TLS_MODE_INVALID
)
1504 return m
->dns_over_tls_mode
;
1506 return DNS_OVER_TLS_NO
;
1509 void manager_dnssec_verdict(Manager
*m
, DnssecVerdict verdict
, const DnsResourceKey
*key
) {
1511 assert(verdict
>= 0);
1512 assert(verdict
< _DNSSEC_VERDICT_MAX
);
1514 if (DEBUG_LOGGING
) {
1515 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
1517 log_debug("Found verdict for lookup %s: %s",
1518 dns_resource_key_to_string(key
, s
, sizeof s
),
1519 dnssec_verdict_to_string(verdict
));
1522 m
->n_dnssec_verdict
[verdict
]++;
1525 bool manager_routable(Manager
*m
) {
1530 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1532 HASHMAP_FOREACH(l
, m
->links
)
1533 if (link_relevant(l
, AF_UNSPEC
, false))
1539 void manager_flush_caches(Manager
*m
, int log_level
) {
1542 LIST_FOREACH(scopes
, scope
, m
->dns_scopes
)
1543 dns_cache_flush(&scope
->cache
);
1545 log_full(log_level
, "Flushed all caches.");
1548 void manager_reset_server_features(Manager
*m
) {
1551 dns_server_reset_features_all(m
->dns_servers
);
1552 dns_server_reset_features_all(m
->fallback_dns_servers
);
1554 HASHMAP_FOREACH(l
, m
->links
)
1555 dns_server_reset_features_all(l
->dns_servers
);
1557 log_info("Resetting learnt feature levels on all servers.");
1560 void manager_cleanup_saved_user(Manager
*m
) {
1561 _cleanup_closedir_
DIR *d
= NULL
;
1565 /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1566 * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1567 * be restarted without losing this data. */
1569 d
= opendir("/run/systemd/resolve/netif/");
1571 if (errno
== ENOENT
)
1574 log_warning_errno(errno
, "Failed to open interface directory: %m");
1578 FOREACH_DIRENT_ALL(de
, d
, log_error_errno(errno
, "Failed to read interface directory: %m")) {
1579 _cleanup_free_
char *p
= NULL
;
1583 if (!IN_SET(de
->d_type
, DT_UNKNOWN
, DT_REG
))
1586 if (dot_or_dot_dot(de
->d_name
))
1589 ifindex
= parse_ifindex(de
->d_name
);
1590 if (ifindex
< 0) /* Probably some temporary file from a previous run. Delete it */
1593 l
= hashmap_get(m
->links
, INT_TO_PTR(ifindex
));
1594 if (!l
) /* link vanished */
1597 if (l
->is_managed
) /* now managed by networkd, hence the bus settings are useless */
1603 p
= path_join("/run/systemd/resolve/netif", de
->d_name
);
1613 bool manager_next_dnssd_names(Manager
*m
) {
1620 HASHMAP_FOREACH(s
, m
->dnssd_services
) {
1621 _cleanup_free_
char * new_name
= NULL
;
1626 r
= manager_next_random_name(s
->name_template
, &new_name
);
1628 log_warning_errno(r
, "Failed to get new name for service '%s': %m", s
->name
);
1632 free_and_replace(s
->name_template
, new_name
);
1634 s
->withdrawn
= false;
1640 manager_refresh_rrs(m
);
1645 bool manager_server_is_stub(Manager
*m
, DnsServer
*s
) {
1646 DnsStubListenerExtra
*l
;
1651 /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1652 * extra careful, and check here again */
1653 if (s
->family
== AF_INET
&&
1654 s
->address
.in
.s_addr
== htobe32(INADDR_DNS_STUB
) &&
1655 dns_server_port(s
) == 53)
1658 /* Main reason to call this is to check server data against the extra listeners, and filter things
1660 ORDERED_SET_FOREACH(l
, m
->dns_extra_stub_listeners
)
1661 if (s
->family
== l
->family
&&
1662 in_addr_equal(s
->family
, &s
->address
, &l
->address
) &&
1663 dns_server_port(s
) == dns_stub_listener_extra_port(l
))
1669 int socket_disable_pmtud(int fd
, int af
) {
1674 if (af
== AF_UNSPEC
) {
1675 r
= socket_get_family(fd
, &af
);
1683 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1684 * PMTU forgery vulnerabilities.
1686 * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1687 * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1688 * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1691 * This helps mitigating the PMTUD vulnerability described here:
1693 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1695 * Similar logic is in place in most DNS servers.
1697 * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1698 * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1699 * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1700 * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1701 * fragments seen — and if we need larger packets always go to TCP.
1704 r
= setsockopt_int(fd
, IPPROTO_IP
, IP_MTU_DISCOVER
, IP_PMTUDISC_OMIT
);
1712 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1713 * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1714 * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1715 * because there's nothing that could be fragmented further anymore. */
1717 r
= setsockopt_int(fd
, IPPROTO_IPV6
, IPV6_MTU
, IPV6_MIN_MTU
);
1725 return -EAFNOSUPPORT
;