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
;
196 /* First, subscribe to interfaces coming and going */
197 r
= sd_netlink_open(&m
->rtnl
);
201 r
= sd_netlink_attach_event(m
->rtnl
, m
->event
, SD_EVENT_PRIORITY_IMPORTANT
);
205 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_NEWLINK
, manager_process_link
, NULL
, m
, "resolve-NEWLINK");
209 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_DELLINK
, manager_process_link
, NULL
, m
, "resolve-DELLINK");
213 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_NEWADDR
, manager_process_address
, NULL
, m
, "resolve-NEWADDR");
217 r
= sd_netlink_add_match(m
->rtnl
, NULL
, RTM_DELADDR
, manager_process_address
, NULL
, m
, "resolve-DELADDR");
221 /* Then, enumerate all links */
222 r
= sd_rtnl_message_new_link(m
->rtnl
, &req
, RTM_GETLINK
, 0);
226 r
= sd_netlink_message_set_request_dump(req
, true);
230 r
= sd_netlink_call(m
->rtnl
, req
, 0, &reply
);
234 for (sd_netlink_message
*i
= reply
; i
; i
= sd_netlink_message_next(i
)) {
235 r
= manager_process_link(m
->rtnl
, i
, m
);
240 req
= sd_netlink_message_unref(req
);
241 reply
= sd_netlink_message_unref(reply
);
243 /* Finally, enumerate all addresses, too */
244 r
= sd_rtnl_message_new_addr(m
->rtnl
, &req
, RTM_GETADDR
, 0, AF_UNSPEC
);
248 r
= sd_netlink_message_set_request_dump(req
, true);
252 r
= sd_netlink_call(m
->rtnl
, req
, 0, &reply
);
256 for (sd_netlink_message
*i
= reply
; i
; i
= sd_netlink_message_next(i
)) {
257 r
= manager_process_address(m
->rtnl
, i
, m
);
265 static int on_network_event(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
266 Manager
*m
= ASSERT_PTR(userdata
);
270 sd_network_monitor_flush(m
->network_monitor
);
272 HASHMAP_FOREACH(l
, m
->links
) {
275 log_warning_errno(r
, "Failed to update monitor information for %i: %m", l
->ifindex
);
278 (void) manager_write_resolv_conf(m
);
279 (void) manager_send_changed(m
, "DNS");
284 static int manager_network_monitor_listen(Manager
*m
) {
289 r
= sd_network_monitor_new(&m
->network_monitor
, NULL
);
293 fd
= sd_network_monitor_get_fd(m
->network_monitor
);
297 events
= sd_network_monitor_get_events(m
->network_monitor
);
301 r
= sd_event_add_io(m
->event
, &m
->network_event_source
, fd
, events
, &on_network_event
, m
);
305 r
= sd_event_source_set_priority(m
->network_event_source
, SD_EVENT_PRIORITY_IMPORTANT
+5);
309 (void) sd_event_source_set_description(m
->network_event_source
, "network-monitor");
314 static int manager_clock_change_listen(Manager
*m
);
316 static int on_clock_change(sd_event_source
*source
, int fd
, uint32_t revents
, void *userdata
) {
317 Manager
*m
= ASSERT_PTR(userdata
);
319 /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
320 * the system clock into consideration, and if the clock changes the old validations might have been
321 * wrong. Let's redo all validation with the new, correct time.
323 * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
324 * we might be connected to a different network now without this being visible in a dropped link
327 log_info("Clock change detected. Flushing caches.");
328 manager_flush_caches(m
, LOG_DEBUG
/* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
330 /* The clock change timerfd is unusable after it triggered once, create a new one. */
331 return manager_clock_change_listen(m
);
334 static int manager_clock_change_listen(Manager
*m
) {
339 m
->clock_change_event_source
= sd_event_source_disable_unref(m
->clock_change_event_source
);
341 r
= event_add_time_change(m
->event
, &m
->clock_change_event_source
, on_clock_change
, m
);
343 return log_error_errno(r
, "Failed to create clock change event source: %m");
348 static int determine_hostnames(char **full_hostname
, char **llmnr_hostname
, char **mdns_hostname
) {
349 _cleanup_free_
char *h
= NULL
, *n
= NULL
;
352 assert(full_hostname
);
353 assert(llmnr_hostname
);
354 assert(mdns_hostname
);
356 r
= resolve_system_hostname(&h
, &n
);
360 r
= dns_name_concat(n
, "local", 0, mdns_hostname
);
362 return log_error_errno(r
, "Failed to determine mDNS hostname: %m");
364 *llmnr_hostname
= TAKE_PTR(n
);
365 *full_hostname
= TAKE_PTR(h
);
370 static char* fallback_hostname(void) {
372 /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
373 * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
376 _cleanup_free_
char *n
= get_default_hostname();
381 return strdup("linux");
386 static int make_fallback_hostnames(char **full_hostname
, char **llmnr_hostname
, char **mdns_hostname
) {
387 _cleanup_free_
char *h
= NULL
, *n
= NULL
, *m
= NULL
;
388 char label
[DNS_LABEL_MAX
];
392 assert(full_hostname
);
393 assert(llmnr_hostname
);
394 assert(mdns_hostname
);
396 p
= h
= fallback_hostname();
400 r
= dns_label_unescape(&p
, label
, sizeof label
, 0);
402 return log_error_errno(r
, "Failed to unescape fallback hostname: %m");
404 assert(r
> 0); /* The fallback hostname must have at least one label */
406 r
= dns_label_escape_new(label
, r
, &n
);
408 return log_error_errno(r
, "Failed to escape fallback hostname: %m");
410 r
= dns_name_concat(n
, "local", 0, &m
);
412 return log_error_errno(r
, "Failed to concatenate mDNS hostname: %m");
414 *llmnr_hostname
= TAKE_PTR(n
);
415 *mdns_hostname
= TAKE_PTR(m
);
416 *full_hostname
= TAKE_PTR(h
);
421 static int on_hostname_change(sd_event_source
*es
, int fd
, uint32_t revents
, void *userdata
) {
422 _cleanup_free_
char *full_hostname
= NULL
, *llmnr_hostname
= NULL
, *mdns_hostname
= NULL
;
423 Manager
*m
= ASSERT_PTR(userdata
);
424 bool llmnr_hostname_changed
;
427 r
= determine_hostnames(&full_hostname
, &llmnr_hostname
, &mdns_hostname
);
429 log_warning_errno(r
, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
430 return 0; /* ignore invalid hostnames */
433 llmnr_hostname_changed
= !streq(llmnr_hostname
, m
->llmnr_hostname
);
434 if (streq(full_hostname
, m
->full_hostname
) &&
435 !llmnr_hostname_changed
&&
436 streq(mdns_hostname
, m
->mdns_hostname
))
439 log_info("System hostname changed to '%s'.", full_hostname
);
441 free_and_replace(m
->full_hostname
, full_hostname
);
442 free_and_replace(m
->llmnr_hostname
, llmnr_hostname
);
443 free_and_replace(m
->mdns_hostname
, mdns_hostname
);
445 manager_refresh_rrs(m
);
446 (void) manager_send_changed(m
, "LLMNRHostname");
451 static int manager_watch_hostname(Manager
*m
) {
456 m
->hostname_fd
= open("/proc/sys/kernel/hostname",
457 O_RDONLY
|O_CLOEXEC
|O_NONBLOCK
|O_NOCTTY
);
458 if (m
->hostname_fd
< 0) {
459 log_warning_errno(errno
, "Failed to watch hostname: %m");
463 r
= sd_event_add_io(m
->event
, &m
->hostname_event_source
, m
->hostname_fd
, 0, on_hostname_change
, m
);
466 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
467 m
->hostname_fd
= safe_close(m
->hostname_fd
);
469 return log_error_errno(r
, "Failed to add hostname event source: %m");
472 (void) sd_event_source_set_description(m
->hostname_event_source
, "hostname");
474 r
= determine_hostnames(&m
->full_hostname
, &m
->llmnr_hostname
, &m
->mdns_hostname
);
476 _cleanup_free_
char *d
= NULL
;
478 d
= fallback_hostname();
482 log_info("Defaulting to hostname '%s'.", d
);
484 r
= make_fallback_hostnames(&m
->full_hostname
, &m
->llmnr_hostname
, &m
->mdns_hostname
);
488 log_info("Using system hostname '%s'.", m
->full_hostname
);
493 static int manager_sigusr1(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
494 _cleanup_free_
char *buffer
= NULL
;
495 _cleanup_fclose_
FILE *f
= NULL
;
496 Manager
*m
= ASSERT_PTR(userdata
);
503 f
= open_memstream_unlocked(&buffer
, &size
);
507 LIST_FOREACH(scopes
, scope
, m
->dns_scopes
)
508 dns_scope_dump(scope
, f
);
510 LIST_FOREACH(servers
, server
, m
->dns_servers
)
511 dns_server_dump(server
, f
);
512 LIST_FOREACH(servers
, server
, m
->fallback_dns_servers
)
513 dns_server_dump(server
, f
);
514 HASHMAP_FOREACH(l
, m
->links
)
515 LIST_FOREACH(servers
, server
, l
->dns_servers
)
516 dns_server_dump(server
, f
);
518 if (fflush_and_check(f
) < 0)
521 log_dump(LOG_INFO
, buffer
);
525 static int manager_sigusr2(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
526 Manager
*m
= ASSERT_PTR(userdata
);
531 manager_flush_caches(m
, LOG_INFO
);
536 static int manager_sigrtmin1(sd_event_source
*s
, const struct signalfd_siginfo
*si
, void *userdata
) {
537 Manager
*m
= ASSERT_PTR(userdata
);
542 manager_reset_server_features(m
);
546 static int manager_memory_pressure(sd_event_source
*s
, void *userdata
) {
547 Manager
*m
= ASSERT_PTR(userdata
);
549 log_info("Under memory pressure, flushing caches.");
551 manager_flush_caches(m
, LOG_INFO
);
552 sd_event_trim_memory();
557 static int manager_memory_pressure_listen(Manager
*m
) {
562 r
= sd_event_add_memory_pressure(m
->event
, NULL
, manager_memory_pressure
, m
);
564 log_full_errno(ERRNO_IS_NOT_SUPPORTED(r
) || ERRNO_IS_PRIVILEGE(r
) || (r
== -EHOSTDOWN
)? LOG_DEBUG
: LOG_NOTICE
, r
,
565 "Failed to install memory pressure event source, ignoring: %m");
570 int manager_new(Manager
**ret
) {
571 _cleanup_(manager_freep
) Manager
*m
= NULL
;
581 .llmnr_ipv4_udp_fd
= -EBADF
,
582 .llmnr_ipv6_udp_fd
= -EBADF
,
583 .llmnr_ipv4_tcp_fd
= -EBADF
,
584 .llmnr_ipv6_tcp_fd
= -EBADF
,
585 .mdns_ipv4_fd
= -EBADF
,
586 .mdns_ipv6_fd
= -EBADF
,
587 .hostname_fd
= -EBADF
,
589 .llmnr_support
= DEFAULT_LLMNR_MODE
,
590 .mdns_support
= DEFAULT_MDNS_MODE
,
591 .dnssec_mode
= DEFAULT_DNSSEC_MODE
,
592 .dns_over_tls_mode
= DEFAULT_DNS_OVER_TLS_MODE
,
593 .enable_cache
= DNS_CACHE_MODE_YES
,
594 .dns_stub_listener_mode
= DNS_STUB_LISTENER_YES
,
595 .read_resolv_conf
= true,
596 .need_builtin_fallbacks
= true,
597 .etc_hosts_last
= USEC_INFINITY
,
598 .read_etc_hosts
= true,
600 .sigrtmin18_info
.memory_pressure_handler
= manager_memory_pressure
,
601 .sigrtmin18_info
.memory_pressure_userdata
= m
,
604 r
= dns_trust_anchor_load(&m
->trust_anchor
);
608 r
= manager_parse_config_file(m
);
610 log_warning_errno(r
, "Failed to parse configuration file: %m");
612 #if ENABLE_DNS_OVER_TLS
613 r
= dnstls_manager_init(m
);
618 r
= sd_event_default(&m
->event
);
622 (void) sd_event_add_signal(m
->event
, NULL
, SIGTERM
, NULL
, NULL
);
623 (void) sd_event_add_signal(m
->event
, NULL
, SIGINT
, NULL
, NULL
);
625 (void) sd_event_set_watchdog(m
->event
, true);
627 r
= manager_watch_hostname(m
);
633 log_warning_errno(r
, "Failed to load DNS-SD configuration files: %m");
635 r
= dns_scope_new(m
, &m
->unicast_scope
, NULL
, DNS_PROTOCOL_DNS
, AF_UNSPEC
);
639 r
= manager_network_monitor_listen(m
);
643 r
= manager_rtnl_listen(m
);
647 r
= manager_clock_change_listen(m
);
651 r
= manager_memory_pressure_listen(m
);
655 r
= manager_connect_bus(m
);
659 (void) sd_event_add_signal(m
->event
, &m
->sigusr1_event_source
, SIGUSR1
, manager_sigusr1
, m
);
660 (void) sd_event_add_signal(m
->event
, &m
->sigusr2_event_source
, SIGUSR2
, manager_sigusr2
, m
);
661 (void) sd_event_add_signal(m
->event
, &m
->sigrtmin1_event_source
, SIGRTMIN
+1, manager_sigrtmin1
, m
);
662 (void) sd_event_add_signal(m
->event
, NULL
, SIGRTMIN
+18, sigrtmin18_handler
, &m
->sigrtmin18_info
);
664 manager_cleanup_saved_user(m
);
671 int manager_start(Manager
*m
) {
676 r
= manager_dns_stub_start(m
);
680 r
= manager_varlink_init(m
);
687 Manager
*manager_free(Manager
*m
) {
694 dns_server_unlink_all(m
->dns_servers
);
695 dns_server_unlink_all(m
->fallback_dns_servers
);
696 dns_search_domain_unlink_all(m
->search_domains
);
698 while ((l
= hashmap_first(m
->links
)))
701 while (m
->dns_queries
)
702 dns_query_free(m
->dns_queries
);
704 m
->stub_queries_by_packet
= hashmap_free(m
->stub_queries_by_packet
);
706 dns_scope_free(m
->unicast_scope
);
708 /* At this point only orphaned streams should remain. All others should have been freed already by their
710 while (m
->dns_streams
)
711 dns_stream_unref(m
->dns_streams
);
713 #if ENABLE_DNS_OVER_TLS
714 dnstls_manager_free(m
);
717 hashmap_free(m
->links
);
718 hashmap_free(m
->dns_transactions
);
720 sd_event_source_unref(m
->network_event_source
);
721 sd_network_monitor_unref(m
->network_monitor
);
723 sd_netlink_unref(m
->rtnl
);
724 sd_event_source_unref(m
->rtnl_event_source
);
725 sd_event_source_unref(m
->clock_change_event_source
);
727 manager_llmnr_stop(m
);
728 manager_mdns_stop(m
);
729 manager_dns_stub_stop(m
);
730 manager_varlink_done(m
);
732 manager_socket_graveyard_clear(m
);
734 ordered_set_free(m
->dns_extra_stub_listeners
);
736 bus_verify_polkit_async_registry_free(m
->polkit_registry
);
738 sd_bus_flush_close_unref(m
->bus
);
740 sd_event_source_unref(m
->sigusr1_event_source
);
741 sd_event_source_unref(m
->sigusr2_event_source
);
742 sd_event_source_unref(m
->sigrtmin1_event_source
);
744 dns_resource_key_unref(m
->llmnr_host_ipv4_key
);
745 dns_resource_key_unref(m
->llmnr_host_ipv6_key
);
746 dns_resource_key_unref(m
->mdns_host_ipv4_key
);
747 dns_resource_key_unref(m
->mdns_host_ipv6_key
);
749 sd_event_source_unref(m
->hostname_event_source
);
750 safe_close(m
->hostname_fd
);
752 sd_event_unref(m
->event
);
754 free(m
->full_hostname
);
755 free(m
->llmnr_hostname
);
756 free(m
->mdns_hostname
);
758 while ((s
= hashmap_first(m
->dnssd_services
)))
759 dnssd_service_free(s
);
760 hashmap_free(m
->dnssd_services
);
762 dns_trust_anchor_flush(&m
->trust_anchor
);
763 manager_etc_hosts_flush(m
);
768 int manager_recv(Manager
*m
, int fd
, DnsProtocol protocol
, DnsPacket
**ret
) {
769 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
770 CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo
, struct in6_pktinfo
))
771 + CMSG_SPACE(int) /* ttl/hoplimit */
772 + EXTRA_CMSG_SPACE
/* kernel appears to require extra buffer space */) control
;
773 union sockaddr_union sa
;
777 .msg_namelen
= sizeof(sa
),
780 .msg_control
= &control
,
781 .msg_controllen
= sizeof(control
),
783 struct cmsghdr
*cmsg
;
791 ms
= next_datagram_size_fd(fd
);
795 r
= dns_packet_new(&p
, protocol
, ms
, DNS_PACKET_SIZE_MAX
);
799 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->allocated
);
801 l
= recvmsg_safe(fd
, &mh
, 0);
803 if (ERRNO_IS_TRANSIENT(l
))
810 assert(!(mh
.msg_flags
& MSG_TRUNC
));
812 p
->size
= (size_t) l
;
814 p
->family
= sa
.sa
.sa_family
;
815 p
->ipproto
= IPPROTO_UDP
;
816 if (p
->family
== AF_INET
) {
817 p
->sender
.in
= sa
.in
.sin_addr
;
818 p
->sender_port
= be16toh(sa
.in
.sin_port
);
819 } else if (p
->family
== AF_INET6
) {
820 p
->sender
.in6
= sa
.in6
.sin6_addr
;
821 p
->sender_port
= be16toh(sa
.in6
.sin6_port
);
822 p
->ifindex
= sa
.in6
.sin6_scope_id
;
824 return -EAFNOSUPPORT
;
826 p
->timestamp
= now(CLOCK_BOOTTIME
);
828 CMSG_FOREACH(cmsg
, &mh
) {
830 if (cmsg
->cmsg_level
== IPPROTO_IPV6
) {
831 assert(p
->family
== AF_INET6
);
833 switch (cmsg
->cmsg_type
) {
836 struct in6_pktinfo
*i
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
839 p
->ifindex
= i
->ipi6_ifindex
;
841 p
->destination
.in6
= i
->ipi6_addr
;
846 p
->ttl
= *(int *) CMSG_DATA(cmsg
);
849 case IPV6_RECVFRAGSIZE
:
850 p
->fragsize
= *(int *) CMSG_DATA(cmsg
);
853 } else if (cmsg
->cmsg_level
== IPPROTO_IP
) {
854 assert(p
->family
== AF_INET
);
856 switch (cmsg
->cmsg_type
) {
859 struct in_pktinfo
*i
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
862 p
->ifindex
= i
->ipi_ifindex
;
864 p
->destination
.in
= i
->ipi_addr
;
869 p
->ttl
= *(int *) CMSG_DATA(cmsg
);
872 case IP_RECVFRAGSIZE
:
873 p
->fragsize
= *(int *) CMSG_DATA(cmsg
);
879 /* The Linux kernel sets the interface index to the loopback
880 * device if the packet came from the local host since it
881 * avoids the routing table in such a case. Let's unset the
882 * interface index in such a case. */
883 if (p
->ifindex
== LOOPBACK_IFINDEX
)
886 if (protocol
!= DNS_PROTOCOL_DNS
) {
887 /* If we don't know the interface index still, we look for the
888 * first local interface with a matching address. Yuck! */
890 p
->ifindex
= manager_find_ifindex(m
, p
->family
, &p
->destination
);
893 log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
894 dns_protocol_to_string(protocol
), p
->size
, p
->ifindex
, p
->ttl
, p
->fragsize
,
895 IN_ADDR_TO_STRING(p
->family
, &p
->sender
),
896 IN_ADDR_TO_STRING(p
->family
, &p
->destination
));
902 static int sendmsg_loop(int fd
, struct msghdr
*mh
, int flags
) {
909 end
= usec_add(now(CLOCK_MONOTONIC
), SEND_TIMEOUT_USEC
);
912 if (sendmsg(fd
, mh
, flags
) >= 0)
919 r
= fd_wait_for_event(fd
, POLLOUT
, LESS_BY(end
, now(CLOCK_MONOTONIC
)));
921 if (ERRNO_IS_TRANSIENT(r
))
930 static int write_loop(int fd
, void *message
, size_t length
) {
937 end
= usec_add(now(CLOCK_MONOTONIC
), SEND_TIMEOUT_USEC
);
940 if (write(fd
, message
, length
) >= 0)
947 r
= fd_wait_for_event(fd
, POLLOUT
, LESS_BY(end
, now(CLOCK_MONOTONIC
)));
949 if (ERRNO_IS_TRANSIENT(r
))
958 int manager_write(Manager
*m
, int fd
, DnsPacket
*p
) {
961 log_debug("Sending %s%s packet with id %" PRIu16
" of size %zu.",
962 DNS_PACKET_TC(p
) ? "truncated (!) " : "",
963 DNS_PACKET_QR(p
) ? "response" : "query",
967 r
= write_loop(fd
, DNS_PACKET_DATA(p
), p
->size
);
974 static int manager_ipv4_send(
978 const struct in_addr
*destination
,
980 const struct in_addr
*source
,
983 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo
))) control
= {};
984 union sockaddr_union sa
;
990 .msg_namelen
= sizeof(sa
.in
),
999 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->size
);
1001 sa
= (union sockaddr_union
) {
1002 .in
.sin_family
= AF_INET
,
1003 .in
.sin_addr
= *destination
,
1004 .in
.sin_port
= htobe16(port
),
1008 struct cmsghdr
*cmsg
;
1009 struct in_pktinfo
*pi
;
1011 mh
.msg_control
= &control
;
1012 mh
.msg_controllen
= sizeof(control
);
1014 cmsg
= CMSG_FIRSTHDR(&mh
);
1015 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct in_pktinfo
));
1016 cmsg
->cmsg_level
= IPPROTO_IP
;
1017 cmsg
->cmsg_type
= IP_PKTINFO
;
1019 pi
= (struct in_pktinfo
*) CMSG_DATA(cmsg
);
1020 pi
->ipi_ifindex
= ifindex
;
1023 pi
->ipi_spec_dst
= *source
;
1026 return sendmsg_loop(fd
, &mh
, 0);
1029 static int manager_ipv6_send(
1033 const struct in6_addr
*destination
,
1035 const struct in6_addr
*source
,
1038 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo
))) control
= {};
1039 union sockaddr_union sa
;
1041 struct msghdr mh
= {
1045 .msg_namelen
= sizeof(sa
.in6
),
1050 assert(destination
);
1054 iov
= IOVEC_MAKE(DNS_PACKET_DATA(p
), p
->size
);
1056 sa
= (union sockaddr_union
) {
1057 .in6
.sin6_family
= AF_INET6
,
1058 .in6
.sin6_addr
= *destination
,
1059 .in6
.sin6_port
= htobe16(port
),
1060 .in6
.sin6_scope_id
= ifindex
,
1064 struct cmsghdr
*cmsg
;
1065 struct in6_pktinfo
*pi
;
1067 mh
.msg_control
= &control
;
1068 mh
.msg_controllen
= sizeof(control
);
1070 cmsg
= CMSG_FIRSTHDR(&mh
);
1071 cmsg
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
1072 cmsg
->cmsg_level
= IPPROTO_IPV6
;
1073 cmsg
->cmsg_type
= IPV6_PKTINFO
;
1075 pi
= (struct in6_pktinfo
*) CMSG_DATA(cmsg
);
1076 pi
->ipi6_ifindex
= ifindex
;
1079 pi
->ipi6_addr
= *source
;
1082 return sendmsg_loop(fd
, &mh
, 0);
1085 static int dns_question_to_json(DnsQuestion
*q
, JsonVariant
**ret
) {
1086 _cleanup_(json_variant_unrefp
) JsonVariant
*l
= NULL
;
1087 DnsResourceKey
*key
;
1092 DNS_QUESTION_FOREACH(key
, q
) {
1093 _cleanup_(json_variant_unrefp
) JsonVariant
*v
= NULL
;
1095 r
= dns_resource_key_to_json(key
, &v
);
1099 r
= json_variant_append_array(&l
, v
);
1108 int manager_monitor_send(
1113 DnsQuestion
*question_idna
,
1114 DnsQuestion
*question_utf8
,
1115 DnsQuestion
*collected_questions
,
1116 DnsAnswer
*answer
) {
1118 _cleanup_(json_variant_unrefp
) JsonVariant
*jquestion
= NULL
, *jcollected_questions
= NULL
, *janswer
= NULL
;
1119 _cleanup_(dns_question_unrefp
) DnsQuestion
*merged
= NULL
;
1120 Varlink
*connection
;
1126 if (set_isempty(m
->varlink_subscription
))
1129 /* Merge both questions format into one */
1130 r
= dns_question_merge(question_idna
, question_utf8
, &merged
);
1132 return log_error_errno(r
, "Failed to merge UTF8/IDNA questions: %m");
1134 /* Convert the current primary question to JSON */
1135 r
= dns_question_to_json(merged
, &jquestion
);
1137 return log_error_errno(r
, "Failed to convert question to JSON: %m");
1139 /* Generate a JSON array of the questions preceding the current one in the CNAME chain */
1140 r
= dns_question_to_json(collected_questions
, &jcollected_questions
);
1142 return log_error_errno(r
, "Failed to convert question to JSON: %m");
1144 DNS_ANSWER_FOREACH_ITEM(rri
, answer
) {
1145 _cleanup_(json_variant_unrefp
) JsonVariant
*v
= NULL
, *w
= NULL
;
1147 r
= dns_resource_record_to_json(rri
->rr
, &v
);
1149 return log_error_errno(r
, "Failed to convert answer resource record to JSON: %m");
1151 r
= dns_resource_record_to_wire_format(rri
->rr
, /* canonical= */ false); /* don't use DNSSEC canonical format, since it removes casing, but we want that for DNS_SD compat */
1153 return log_error_errno(r
, "Failed to generate RR wire format: %m");
1155 r
= json_build(&w
, JSON_BUILD_OBJECT(
1156 JSON_BUILD_PAIR_CONDITION(v
, "rr", JSON_BUILD_VARIANT(v
)),
1157 JSON_BUILD_PAIR("raw", JSON_BUILD_BASE64(rri
->rr
->wire_format
, rri
->rr
->wire_format_size
)),
1158 JSON_BUILD_PAIR_CONDITION(rri
->ifindex
> 0, "ifindex", JSON_BUILD_INTEGER(rri
->ifindex
))));
1160 return log_error_errno(r
, "Failed to make answer RR object: %m");
1162 r
= json_variant_append_array(&janswer
, w
);
1164 return log_debug_errno(r
, "Failed to append notification entry to array: %m");
1167 SET_FOREACH(connection
, m
->varlink_subscription
) {
1168 r
= varlink_notifyb(connection
,
1169 JSON_BUILD_OBJECT(JSON_BUILD_PAIR("state", JSON_BUILD_STRING(dns_transaction_state_to_string(state
))),
1170 JSON_BUILD_PAIR_CONDITION(state
== DNS_TRANSACTION_RCODE_FAILURE
, "rcode", JSON_BUILD_INTEGER(rcode
)),
1171 JSON_BUILD_PAIR_CONDITION(state
== DNS_TRANSACTION_ERRNO
, "errno", JSON_BUILD_INTEGER(error
)),
1172 JSON_BUILD_PAIR("question", JSON_BUILD_VARIANT(jquestion
)),
1173 JSON_BUILD_PAIR_CONDITION(jcollected_questions
, "collectedQuestions", JSON_BUILD_VARIANT(jcollected_questions
)),
1174 JSON_BUILD_PAIR_CONDITION(janswer
, "answer", JSON_BUILD_VARIANT(janswer
))));
1176 log_debug_errno(r
, "Failed to send monitor event, ignoring: %m");
1187 const union in_addr_union
*destination
,
1189 const union in_addr_union
*source
,
1194 assert(destination
);
1198 log_debug("Sending %s%s packet with id %" PRIu16
" on interface %i/%s of size %zu.",
1199 DNS_PACKET_TC(p
) ? "truncated (!) " : "",
1200 DNS_PACKET_QR(p
) ? "response" : "query",
1202 ifindex
, af_to_name(family
),
1205 if (family
== AF_INET
)
1206 return manager_ipv4_send(m
, fd
, ifindex
, &destination
->in
, port
, source
? &source
->in
: NULL
, p
);
1207 if (family
== AF_INET6
)
1208 return manager_ipv6_send(m
, fd
, ifindex
, &destination
->in6
, port
, source
? &source
->in6
: NULL
, p
);
1210 return -EAFNOSUPPORT
;
1213 uint32_t manager_find_mtu(Manager
*m
) {
1217 /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1218 * works on all interfaces we know of that have an IP address associated */
1220 HASHMAP_FOREACH(l
, m
->links
) {
1221 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1225 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1226 * let's ignore this link. */
1227 if (l
->mtu
< MIN(UDP4_PACKET_HEADER_SIZE
+ DNS_PACKET_HEADER_SIZE
,
1228 UDP6_PACKET_HEADER_SIZE
+ DNS_PACKET_HEADER_SIZE
))
1231 if (mtu
<= 0 || l
->mtu
< mtu
)
1235 if (mtu
== 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1241 int manager_find_ifindex(Manager
*m
, int family
, const union in_addr_union
*in_addr
) {
1246 if (!IN_SET(family
, AF_INET
, AF_INET6
))
1252 a
= manager_find_link_address(m
, family
, in_addr
);
1254 return a
->link
->ifindex
;
1259 void manager_refresh_rrs(Manager
*m
) {
1265 m
->llmnr_host_ipv4_key
= dns_resource_key_unref(m
->llmnr_host_ipv4_key
);
1266 m
->llmnr_host_ipv6_key
= dns_resource_key_unref(m
->llmnr_host_ipv6_key
);
1267 m
->mdns_host_ipv4_key
= dns_resource_key_unref(m
->mdns_host_ipv4_key
);
1268 m
->mdns_host_ipv6_key
= dns_resource_key_unref(m
->mdns_host_ipv6_key
);
1270 HASHMAP_FOREACH(l
, m
->links
)
1271 link_add_rrs(l
, true);
1273 if (m
->mdns_support
== RESOLVE_SUPPORT_YES
)
1274 HASHMAP_FOREACH(s
, m
->dnssd_services
)
1275 if (dnssd_update_rrs(s
) < 0)
1276 log_warning("Failed to refresh DNS-SD service '%s'", s
->name
);
1278 HASHMAP_FOREACH(l
, m
->links
)
1279 link_add_rrs(l
, false);
1282 static int manager_next_random_name(const char *old
, char **ret_new
) {
1291 if (!ascii_isdigit(p
[-1]))
1297 if (*p
== 0 || safe_atou64(p
, &u
) < 0 || u
<= 0)
1300 /* Add a random number to the old value. This way we can avoid
1301 * that two hosts pick the same hostname, win on IPv4 and lose
1302 * on IPv6 (or vice versa), and pick the same hostname
1303 * replacement hostname, ad infinitum. We still want the
1304 * numbers to go up monotonically, hence we just add a random
1307 random_bytes(&a
, sizeof(a
));
1310 if (asprintf(&n
, "%.*s%" PRIu64
, (int) (p
- old
), old
, u
) < 0)
1318 int manager_next_hostname(Manager
*m
) {
1319 _cleanup_free_
char *h
= NULL
, *k
= NULL
;
1324 r
= manager_next_random_name(m
->llmnr_hostname
, &h
);
1328 r
= dns_name_concat(h
, "local", 0, &k
);
1332 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m
->llmnr_hostname
, h
);
1334 free_and_replace(m
->llmnr_hostname
, h
);
1335 free_and_replace(m
->mdns_hostname
, k
);
1337 manager_refresh_rrs(m
);
1338 (void) manager_send_changed(m
, "LLMNRHostname");
1343 LinkAddress
* manager_find_link_address(Manager
*m
, int family
, const union in_addr_union
*in_addr
) {
1348 if (!IN_SET(family
, AF_INET
, AF_INET6
))
1354 HASHMAP_FOREACH(l
, m
->links
) {
1357 a
= link_find_address(l
, family
, in_addr
);
1365 bool manager_packet_from_local_address(Manager
*m
, DnsPacket
*p
) {
1369 /* Let's see if this packet comes from an IP address we have on any local interface */
1371 return !!manager_find_link_address(m
, p
->family
, &p
->sender
);
1374 bool manager_packet_from_our_transaction(Manager
*m
, DnsPacket
*p
) {
1380 /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1381 * one we just got. If so, it's almost definitely a packet loop of some kind. */
1383 t
= hashmap_get(m
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
1387 return t
->sent
&& dns_packet_equal(t
->sent
, p
);
1390 DnsScope
* manager_find_scope(Manager
*m
, DnsPacket
*p
) {
1396 l
= hashmap_get(m
->links
, INT_TO_PTR(p
->ifindex
));
1400 switch (p
->protocol
) {
1401 case DNS_PROTOCOL_LLMNR
:
1402 if (p
->family
== AF_INET
)
1403 return l
->llmnr_ipv4_scope
;
1404 else if (p
->family
== AF_INET6
)
1405 return l
->llmnr_ipv6_scope
;
1409 case DNS_PROTOCOL_MDNS
:
1410 if (p
->family
== AF_INET
)
1411 return l
->mdns_ipv4_scope
;
1412 else if (p
->family
== AF_INET6
)
1413 return l
->mdns_ipv6_scope
;
1424 void manager_verify_all(Manager
*m
) {
1427 LIST_FOREACH(scopes
, s
, m
->dns_scopes
)
1428 dns_zone_verify_all(&s
->zone
);
1431 int manager_is_own_hostname(Manager
*m
, const char *name
) {
1437 if (m
->llmnr_hostname
) {
1438 r
= dns_name_equal(name
, m
->llmnr_hostname
);
1443 if (m
->mdns_hostname
) {
1444 r
= dns_name_equal(name
, m
->mdns_hostname
);
1449 if (m
->full_hostname
)
1450 return dns_name_equal(name
, m
->full_hostname
);
1455 int manager_compile_dns_servers(Manager
*m
, OrderedSet
**dns
) {
1462 r
= ordered_set_ensure_allocated(dns
, &dns_server_hash_ops
);
1466 /* First add the system-wide servers and domains */
1467 LIST_FOREACH(servers
, s
, m
->dns_servers
) {
1468 r
= ordered_set_put(*dns
, s
);
1475 /* Then, add the per-link servers */
1476 HASHMAP_FOREACH(l
, m
->links
) {
1477 LIST_FOREACH(servers
, s
, l
->dns_servers
) {
1478 r
= ordered_set_put(*dns
, s
);
1486 /* If we found nothing, add the fallback servers */
1487 if (ordered_set_isempty(*dns
)) {
1488 LIST_FOREACH(servers
, s
, m
->fallback_dns_servers
) {
1489 r
= ordered_set_put(*dns
, s
);
1500 /* filter_route is a tri-state:
1502 * = 0 or false: return only domains which should be used for searching
1503 * > 0 or true: return only domains which are for routing only
1505 int manager_compile_search_domains(Manager
*m
, OrderedSet
**domains
, int filter_route
) {
1512 r
= ordered_set_ensure_allocated(domains
, &dns_name_hash_ops
);
1516 LIST_FOREACH(domains
, d
, m
->search_domains
) {
1518 if (filter_route
>= 0 &&
1519 d
->route_only
!= !!filter_route
)
1522 r
= ordered_set_put(*domains
, d
->name
);
1529 HASHMAP_FOREACH(l
, m
->links
) {
1531 LIST_FOREACH(domains
, d
, l
->search_domains
) {
1533 if (filter_route
>= 0 &&
1534 d
->route_only
!= !!filter_route
)
1537 r
= ordered_set_put(*domains
, d
->name
);
1548 DnssecMode
manager_get_dnssec_mode(Manager
*m
) {
1551 if (m
->dnssec_mode
!= _DNSSEC_MODE_INVALID
)
1552 return m
->dnssec_mode
;
1557 bool manager_dnssec_supported(Manager
*m
) {
1563 if (manager_get_dnssec_mode(m
) == DNSSEC_NO
)
1566 server
= manager_get_dns_server(m
);
1567 if (server
&& !dns_server_dnssec_supported(server
))
1570 HASHMAP_FOREACH(l
, m
->links
)
1571 if (!link_dnssec_supported(l
))
1577 DnsOverTlsMode
manager_get_dns_over_tls_mode(Manager
*m
) {
1580 if (m
->dns_over_tls_mode
!= _DNS_OVER_TLS_MODE_INVALID
)
1581 return m
->dns_over_tls_mode
;
1583 return DNS_OVER_TLS_NO
;
1586 void manager_dnssec_verdict(Manager
*m
, DnssecVerdict verdict
, const DnsResourceKey
*key
) {
1588 assert(verdict
>= 0);
1589 assert(verdict
< _DNSSEC_VERDICT_MAX
);
1591 if (DEBUG_LOGGING
) {
1592 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
1594 log_debug("Found verdict for lookup %s: %s",
1595 dns_resource_key_to_string(key
, s
, sizeof s
),
1596 dnssec_verdict_to_string(verdict
));
1599 m
->n_dnssec_verdict
[verdict
]++;
1602 bool manager_routable(Manager
*m
) {
1607 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1609 HASHMAP_FOREACH(l
, m
->links
)
1610 if (link_relevant(l
, AF_UNSPEC
, false))
1616 void manager_flush_caches(Manager
*m
, int log_level
) {
1619 LIST_FOREACH(scopes
, scope
, m
->dns_scopes
)
1620 dns_cache_flush(&scope
->cache
);
1622 log_full(log_level
, "Flushed all caches.");
1625 void manager_reset_server_features(Manager
*m
) {
1628 dns_server_reset_features_all(m
->dns_servers
);
1629 dns_server_reset_features_all(m
->fallback_dns_servers
);
1631 HASHMAP_FOREACH(l
, m
->links
)
1632 dns_server_reset_features_all(l
->dns_servers
);
1634 log_info("Resetting learnt feature levels on all servers.");
1637 void manager_cleanup_saved_user(Manager
*m
) {
1638 _cleanup_closedir_
DIR *d
= NULL
;
1642 /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1643 * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1644 * be restarted without losing this data. */
1646 d
= opendir("/run/systemd/resolve/netif/");
1648 if (errno
== ENOENT
)
1651 log_warning_errno(errno
, "Failed to open interface directory: %m");
1655 FOREACH_DIRENT_ALL(de
, d
, log_error_errno(errno
, "Failed to read interface directory: %m")) {
1656 _cleanup_free_
char *p
= NULL
;
1660 if (!IN_SET(de
->d_type
, DT_UNKNOWN
, DT_REG
))
1663 if (dot_or_dot_dot(de
->d_name
))
1666 ifindex
= parse_ifindex(de
->d_name
);
1667 if (ifindex
< 0) /* Probably some temporary file from a previous run. Delete it */
1670 l
= hashmap_get(m
->links
, INT_TO_PTR(ifindex
));
1671 if (!l
) /* link vanished */
1674 if (l
->is_managed
) /* now managed by networkd, hence the bus settings are useless */
1680 p
= path_join("/run/systemd/resolve/netif", de
->d_name
);
1690 bool manager_next_dnssd_names(Manager
*m
) {
1697 HASHMAP_FOREACH(s
, m
->dnssd_services
) {
1698 _cleanup_free_
char * new_name
= NULL
;
1703 r
= manager_next_random_name(s
->name_template
, &new_name
);
1705 log_warning_errno(r
, "Failed to get new name for service '%s': %m", s
->name
);
1709 free_and_replace(s
->name_template
, new_name
);
1711 s
->withdrawn
= false;
1717 manager_refresh_rrs(m
);
1722 bool manager_server_is_stub(Manager
*m
, DnsServer
*s
) {
1723 DnsStubListenerExtra
*l
;
1728 /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1729 * extra careful, and check here again */
1730 if (s
->family
== AF_INET
&&
1731 s
->address
.in
.s_addr
== htobe32(INADDR_DNS_STUB
) &&
1732 dns_server_port(s
) == 53)
1735 /* Main reason to call this is to check server data against the extra listeners, and filter things
1737 ORDERED_SET_FOREACH(l
, m
->dns_extra_stub_listeners
)
1738 if (s
->family
== l
->family
&&
1739 in_addr_equal(s
->family
, &s
->address
, &l
->address
) &&
1740 dns_server_port(s
) == dns_stub_listener_extra_port(l
))
1746 int socket_disable_pmtud(int fd
, int af
) {
1751 if (af
== AF_UNSPEC
) {
1752 af
= socket_get_family(fd
);
1760 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1761 * PMTU forgery vulnerabilities.
1763 * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1764 * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1765 * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1768 * This helps mitigating the PMTUD vulnerability described here:
1770 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1772 * Similar logic is in place in most DNS servers.
1774 * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1775 * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1776 * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1777 * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1778 * fragments seen — and if we need larger packets always go to TCP.
1781 r
= setsockopt_int(fd
, IPPROTO_IP
, IP_MTU_DISCOVER
, IP_PMTUDISC_OMIT
);
1789 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1790 * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1791 * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1792 * because there's nothing that could be fragmented further anymore. */
1794 r
= setsockopt_int(fd
, IPPROTO_IPV6
, IPV6_MTU
, IPV6_MIN_MTU
);
1802 return -EAFNOSUPPORT
;