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socket-util: fix socket_get_family()
[thirdparty/systemd.git] / src / resolve / resolved-manager.c
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3#include <fcntl.h>
4#include <netinet/in.h>
5#include <poll.h>
6#include <sys/ioctl.h>
7#include <sys/stat.h>
8#include <sys/types.h>
9#include <unistd.h>
10
11#include "af-list.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"
17#include "fd-util.h"
18#include "fileio.h"
19#include "hostname-util.h"
20#include "idn-util.h"
21#include "io-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"
42#include "utf8.h"
43
44#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
45
46static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
47 Manager *m = ASSERT_PTR(userdata);
48 uint16_t type;
49 Link *l;
50 int ifindex, r;
51
52 assert(rtnl);
53 assert(mm);
54
55 r = sd_netlink_message_get_type(mm, &type);
56 if (r < 0)
57 goto fail;
58
59 r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
60 if (r < 0)
61 goto fail;
62
63 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
64
65 switch (type) {
66
67 case RTM_NEWLINK:{
68 bool is_new = !l;
69
70 if (!l) {
71 r = link_new(m, &l, ifindex);
72 if (r < 0)
73 goto fail;
74 }
75
76 r = link_process_rtnl(l, mm);
77 if (r < 0)
78 goto fail;
79
80 r = link_update(l);
81 if (r < 0)
82 goto fail;
83
84 if (is_new)
85 log_debug("Found new link %i/%s", ifindex, l->ifname);
86
87 break;
88 }
89
90 case RTM_DELLINK:
91 if (l) {
92 log_debug("Removing link %i/%s", l->ifindex, l->ifname);
93 link_remove_user(l);
94 link_free(l);
95 }
96
97 break;
98 }
99
100 return 0;
101
102fail:
103 log_warning_errno(r, "Failed to process RTNL link message: %m");
104 return 0;
105}
106
107static 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;
110 uint16_t type;
111 int r, ifindex, family;
112 LinkAddress *a;
113 Link *l;
114
115 assert(rtnl);
116 assert(mm);
117
118 r = sd_netlink_message_get_type(mm, &type);
119 if (r < 0)
120 goto fail;
121
122 r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
123 if (r < 0)
124 goto fail;
125
126 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
127 if (!l)
128 return 0;
129
130 r = sd_rtnl_message_addr_get_family(mm, &family);
131 if (r < 0)
132 goto fail;
133
134 switch (family) {
135
136 case AF_INET:
137 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
138 if (r < 0) {
139 r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
140 if (r < 0)
141 goto fail;
142 }
143
144 break;
145
146 case AF_INET6:
147 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
148 if (r < 0) {
149 r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
150 if (r < 0)
151 goto fail;
152 }
153
154 break;
155
156 default:
157 return 0;
158 }
159
160 a = link_find_address(l, family, &address);
161
162 switch (type) {
163
164 case RTM_NEWADDR:
165
166 if (!a) {
167 r = link_address_new(l, &a, family, &address);
168 if (r < 0)
169 return r;
170 }
171
172 r = link_address_update_rtnl(a, mm);
173 if (r < 0)
174 return r;
175
176 break;
177
178 case RTM_DELADDR:
179 link_address_free(a);
180 break;
181 }
182
183 return 0;
184
185fail:
186 log_warning_errno(r, "Failed to process RTNL address message: %m");
187 return 0;
188}
189
190static int manager_rtnl_listen(Manager *m) {
191 _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
192 int r;
193
194 assert(m);
195
196 /* First, subscribe to interfaces coming and going */
197 r = sd_netlink_open(&m->rtnl);
198 if (r < 0)
199 return r;
200
201 r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
202 if (r < 0)
203 return r;
204
205 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
206 if (r < 0)
207 return r;
208
209 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
210 if (r < 0)
211 return r;
212
213 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
214 if (r < 0)
215 return r;
216
217 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
218 if (r < 0)
219 return r;
220
221 /* Then, enumerate all links */
222 r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
223 if (r < 0)
224 return r;
225
226 r = sd_netlink_message_set_request_dump(req, true);
227 if (r < 0)
228 return r;
229
230 r = sd_netlink_call(m->rtnl, req, 0, &reply);
231 if (r < 0)
232 return r;
233
234 for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
235 r = manager_process_link(m->rtnl, i, m);
236 if (r < 0)
237 return r;
238 }
239
240 req = sd_netlink_message_unref(req);
241 reply = sd_netlink_message_unref(reply);
242
243 /* Finally, enumerate all addresses, too */
244 r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
245 if (r < 0)
246 return r;
247
248 r = sd_netlink_message_set_request_dump(req, true);
249 if (r < 0)
250 return r;
251
252 r = sd_netlink_call(m->rtnl, req, 0, &reply);
253 if (r < 0)
254 return r;
255
256 for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
257 r = manager_process_address(m->rtnl, i, m);
258 if (r < 0)
259 return r;
260 }
261
262 return r;
263}
264
265static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
266 Manager *m = ASSERT_PTR(userdata);
267 Link *l;
268 int r;
269
270 sd_network_monitor_flush(m->network_monitor);
271
272 HASHMAP_FOREACH(l, m->links) {
273 r = link_update(l);
274 if (r < 0)
275 log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
276 }
277
278 (void) manager_write_resolv_conf(m);
279 (void) manager_send_changed(m, "DNS");
280
281 return 0;
282}
283
284static int manager_network_monitor_listen(Manager *m) {
285 int r, fd, events;
286
287 assert(m);
288
289 r = sd_network_monitor_new(&m->network_monitor, NULL);
290 if (r < 0)
291 return r;
292
293 fd = sd_network_monitor_get_fd(m->network_monitor);
294 if (fd < 0)
295 return fd;
296
297 events = sd_network_monitor_get_events(m->network_monitor);
298 if (events < 0)
299 return events;
300
301 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
302 if (r < 0)
303 return r;
304
305 r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
306 if (r < 0)
307 return r;
308
309 (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
310
311 return 0;
312}
313
314static int manager_clock_change_listen(Manager *m);
315
316static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
317 Manager *m = ASSERT_PTR(userdata);
318
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.
322 *
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
325 * carrier or so.) */
326
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 */);
329
330 /* The clock change timerfd is unusable after it triggered once, create a new one. */
331 return manager_clock_change_listen(m);
332}
333
334static int manager_clock_change_listen(Manager *m) {
335 int r;
336
337 assert(m);
338
339 m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
340
341 r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
342 if (r < 0)
343 return log_error_errno(r, "Failed to create clock change event source: %m");
344
345 return 0;
346}
347
348static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
349 _cleanup_free_ char *h = NULL, *n = NULL;
350 int r;
351
352 assert(full_hostname);
353 assert(llmnr_hostname);
354 assert(mdns_hostname);
355
356 r = resolve_system_hostname(&h, &n);
357 if (r < 0)
358 return r;
359
360 r = dns_name_concat(n, "local", 0, mdns_hostname);
361 if (r < 0)
362 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
363
364 *llmnr_hostname = TAKE_PTR(n);
365 *full_hostname = TAKE_PTR(h);
366
367 return 0;
368}
369
370static char* fallback_hostname(void) {
371
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"
374 * instead. */
375
376 _cleanup_free_ char *n = get_default_hostname();
377 if (!n)
378 return NULL;
379
380 if (is_localhost(n))
381 return strdup("linux");
382
383 return TAKE_PTR(n);
384}
385
386static 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];
389 const char *p;
390 int r;
391
392 assert(full_hostname);
393 assert(llmnr_hostname);
394 assert(mdns_hostname);
395
396 p = h = fallback_hostname();
397 if (!h)
398 return log_oom();
399
400 r = dns_label_unescape(&p, label, sizeof label, 0);
401 if (r < 0)
402 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
403
404 assert(r > 0); /* The fallback hostname must have at least one label */
405
406 r = dns_label_escape_new(label, r, &n);
407 if (r < 0)
408 return log_error_errno(r, "Failed to escape fallback hostname: %m");
409
410 r = dns_name_concat(n, "local", 0, &m);
411 if (r < 0)
412 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
413
414 *llmnr_hostname = TAKE_PTR(n);
415 *mdns_hostname = TAKE_PTR(m);
416 *full_hostname = TAKE_PTR(h);
417
418 return 0;
419}
420
421static 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;
425 int r;
426
427 r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
428 if (r < 0) {
429 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
430 return 0; /* ignore invalid hostnames */
431 }
432
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))
437 return 0;
438
439 log_info("System hostname changed to '%s'.", full_hostname);
440
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);
444
445 manager_refresh_rrs(m);
446 (void) manager_send_changed(m, "LLMNRHostname");
447
448 return 0;
449}
450
451static int manager_watch_hostname(Manager *m) {
452 int r;
453
454 assert(m);
455
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");
460 return 0;
461 }
462
463 r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
464 if (r < 0) {
465 if (r == -EPERM)
466 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
467 m->hostname_fd = safe_close(m->hostname_fd);
468 else
469 return log_error_errno(r, "Failed to add hostname event source: %m");
470 }
471
472 (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
473
474 r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
475 if (r < 0) {
476 _cleanup_free_ char *d = NULL;
477
478 d = fallback_hostname();
479 if (!d)
480 return log_oom();
481
482 log_info("Defaulting to hostname '%s'.", d);
483
484 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
485 if (r < 0)
486 return r;
487 } else
488 log_info("Using system hostname '%s'.", m->full_hostname);
489
490 return 0;
491}
492
493static 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);
497 size_t size = 0;
498 Link *l;
499
500 assert(s);
501 assert(si);
502
503 f = open_memstream_unlocked(&buffer, &size);
504 if (!f)
505 return log_oom();
506
507 LIST_FOREACH(scopes, scope, m->dns_scopes)
508 dns_scope_dump(scope, f);
509
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);
517
518 if (fflush_and_check(f) < 0)
519 return log_oom();
520
521 log_dump(LOG_INFO, buffer);
522 return 0;
523}
524
525static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
526 Manager *m = ASSERT_PTR(userdata);
527
528 assert(s);
529 assert(si);
530
531 manager_flush_caches(m, LOG_INFO);
532
533 return 0;
534}
535
536static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
537 Manager *m = ASSERT_PTR(userdata);
538
539 assert(s);
540 assert(si);
541
542 manager_reset_server_features(m);
543 return 0;
544}
545
546static int manager_memory_pressure(sd_event_source *s, void *userdata) {
547 Manager *m = ASSERT_PTR(userdata);
548
549 log_info("Under memory pressure, flushing caches.");
550
551 manager_flush_caches(m, LOG_INFO);
552 sd_event_trim_memory();
553
554 return 0;
555}
556
557static int manager_memory_pressure_listen(Manager *m) {
558 int r;
559
560 assert(m);
561
562 r = sd_event_add_memory_pressure(m->event, NULL, manager_memory_pressure, m);
563 if (r < 0)
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");
566
567 return 0;
568}
569
570int manager_new(Manager **ret) {
571 _cleanup_(manager_freep) Manager *m = NULL;
572 int r;
573
574 assert(ret);
575
576 m = new(Manager, 1);
577 if (!m)
578 return -ENOMEM;
579
580 *m = (Manager) {
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,
588
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,
599
600 .sigrtmin18_info.memory_pressure_handler = manager_memory_pressure,
601 .sigrtmin18_info.memory_pressure_userdata = m,
602 };
603
604 r = dns_trust_anchor_load(&m->trust_anchor);
605 if (r < 0)
606 return r;
607
608 r = manager_parse_config_file(m);
609 if (r < 0)
610 log_warning_errno(r, "Failed to parse configuration file: %m");
611
612#if ENABLE_DNS_OVER_TLS
613 r = dnstls_manager_init(m);
614 if (r < 0)
615 return r;
616#endif
617
618 r = sd_event_default(&m->event);
619 if (r < 0)
620 return r;
621
622 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
623 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
624
625 (void) sd_event_set_watchdog(m->event, true);
626
627 r = manager_watch_hostname(m);
628 if (r < 0)
629 return r;
630
631 r = dnssd_load(m);
632 if (r < 0)
633 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
634
635 r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
636 if (r < 0)
637 return r;
638
639 r = manager_network_monitor_listen(m);
640 if (r < 0)
641 return r;
642
643 r = manager_rtnl_listen(m);
644 if (r < 0)
645 return r;
646
647 r = manager_clock_change_listen(m);
648 if (r < 0)
649 return r;
650
651 r = manager_memory_pressure_listen(m);
652 if (r < 0)
653 return r;
654
655 r = manager_connect_bus(m);
656 if (r < 0)
657 return r;
658
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);
663
664 manager_cleanup_saved_user(m);
665
666 *ret = TAKE_PTR(m);
667
668 return 0;
669}
670
671int manager_start(Manager *m) {
672 int r;
673
674 assert(m);
675
676 r = manager_dns_stub_start(m);
677 if (r < 0)
678 return r;
679
680 r = manager_varlink_init(m);
681 if (r < 0)
682 return r;
683
684 return 0;
685}
686
687Manager *manager_free(Manager *m) {
688 Link *l;
689 DnssdService *s;
690
691 if (!m)
692 return NULL;
693
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);
697
698 while ((l = hashmap_first(m->links)))
699 link_free(l);
700
701 while (m->dns_queries)
702 dns_query_free(m->dns_queries);
703
704 m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
705
706 dns_scope_free(m->unicast_scope);
707
708 /* At this point only orphaned streams should remain. All others should have been freed already by their
709 * owners */
710 while (m->dns_streams)
711 dns_stream_unref(m->dns_streams);
712
713#if ENABLE_DNS_OVER_TLS
714 dnstls_manager_free(m);
715#endif
716
717 hashmap_free(m->links);
718 hashmap_free(m->dns_transactions);
719
720 sd_event_source_unref(m->network_event_source);
721 sd_network_monitor_unref(m->network_monitor);
722
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);
726
727 manager_llmnr_stop(m);
728 manager_mdns_stop(m);
729 manager_dns_stub_stop(m);
730 manager_varlink_done(m);
731
732 manager_socket_graveyard_clear(m);
733
734 ordered_set_free(m->dns_extra_stub_listeners);
735
736 bus_verify_polkit_async_registry_free(m->polkit_registry);
737
738 sd_bus_flush_close_unref(m->bus);
739
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);
743
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);
748
749 sd_event_source_unref(m->hostname_event_source);
750 safe_close(m->hostname_fd);
751
752 sd_event_unref(m->event);
753
754 free(m->full_hostname);
755 free(m->llmnr_hostname);
756 free(m->mdns_hostname);
757
758 while ((s = hashmap_first(m->dnssd_services)))
759 dnssd_service_free(s);
760 hashmap_free(m->dnssd_services);
761
762 dns_trust_anchor_flush(&m->trust_anchor);
763 manager_etc_hosts_flush(m);
764
765 return mfree(m);
766}
767
768int 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;
774 struct iovec iov;
775 struct msghdr mh = {
776 .msg_name = &sa.sa,
777 .msg_namelen = sizeof(sa),
778 .msg_iov = &iov,
779 .msg_iovlen = 1,
780 .msg_control = &control,
781 .msg_controllen = sizeof(control),
782 };
783 struct cmsghdr *cmsg;
784 ssize_t ms, l;
785 int r;
786
787 assert(m);
788 assert(fd >= 0);
789 assert(ret);
790
791 ms = next_datagram_size_fd(fd);
792 if (ms < 0)
793 return ms;
794
795 r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
796 if (r < 0)
797 return r;
798
799 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
800
801 l = recvmsg_safe(fd, &mh, 0);
802 if (l < 0) {
803 if (ERRNO_IS_TRANSIENT(l))
804 return 0;
805 return l;
806 }
807 if (l == 0)
808 return 0;
809
810 assert(!(mh.msg_flags & MSG_TRUNC));
811
812 p->size = (size_t) l;
813
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;
823 } else
824 return -EAFNOSUPPORT;
825
826 p->timestamp = now(CLOCK_BOOTTIME);
827
828 CMSG_FOREACH(cmsg, &mh) {
829
830 if (cmsg->cmsg_level == IPPROTO_IPV6) {
831 assert(p->family == AF_INET6);
832
833 switch (cmsg->cmsg_type) {
834
835 case IPV6_PKTINFO: {
836 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
837
838 if (p->ifindex <= 0)
839 p->ifindex = i->ipi6_ifindex;
840
841 p->destination.in6 = i->ipi6_addr;
842 break;
843 }
844
845 case IPV6_HOPLIMIT:
846 p->ttl = *(int *) CMSG_DATA(cmsg);
847 break;
848
849 case IPV6_RECVFRAGSIZE:
850 p->fragsize = *(int *) CMSG_DATA(cmsg);
851 break;
852 }
853 } else if (cmsg->cmsg_level == IPPROTO_IP) {
854 assert(p->family == AF_INET);
855
856 switch (cmsg->cmsg_type) {
857
858 case IP_PKTINFO: {
859 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
860
861 if (p->ifindex <= 0)
862 p->ifindex = i->ipi_ifindex;
863
864 p->destination.in = i->ipi_addr;
865 break;
866 }
867
868 case IP_TTL:
869 p->ttl = *(int *) CMSG_DATA(cmsg);
870 break;
871
872 case IP_RECVFRAGSIZE:
873 p->fragsize = *(int *) CMSG_DATA(cmsg);
874 break;
875 }
876 }
877 }
878
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)
884 p->ifindex = 0;
885
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! */
889 if (p->ifindex <= 0)
890 p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
891 }
892
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));
897
898 *ret = TAKE_PTR(p);
899 return 1;
900}
901
902static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
903 usec_t end;
904 int r;
905
906 assert(fd >= 0);
907 assert(mh);
908
909 end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
910
911 for (;;) {
912 if (sendmsg(fd, mh, flags) >= 0)
913 return 0;
914 if (errno == EINTR)
915 continue;
916 if (errno != EAGAIN)
917 return -errno;
918
919 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
920 if (r < 0) {
921 if (ERRNO_IS_TRANSIENT(r))
922 continue;
923 return r;
924 }
925 if (r == 0)
926 return -ETIMEDOUT;
927 }
928}
929
930static int write_loop(int fd, void *message, size_t length) {
931 usec_t end;
932 int r;
933
934 assert(fd >= 0);
935 assert(message);
936
937 end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
938
939 for (;;) {
940 if (write(fd, message, length) >= 0)
941 return 0;
942 if (errno == EINTR)
943 continue;
944 if (errno != EAGAIN)
945 return -errno;
946
947 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
948 if (r < 0) {
949 if (ERRNO_IS_TRANSIENT(r))
950 continue;
951 return r;
952 }
953 if (r == 0)
954 return -ETIMEDOUT;
955 }
956}
957
958int manager_write(Manager *m, int fd, DnsPacket *p) {
959 int r;
960
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",
964 DNS_PACKET_ID(p),
965 p->size);
966
967 r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
968 if (r < 0)
969 return r;
970
971 return 0;
972}
973
974static int manager_ipv4_send(
975 Manager *m,
976 int fd,
977 int ifindex,
978 const struct in_addr *destination,
979 uint16_t port,
980 const struct in_addr *source,
981 DnsPacket *p) {
982
983 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
984 union sockaddr_union sa;
985 struct iovec iov;
986 struct msghdr mh = {
987 .msg_iov = &iov,
988 .msg_iovlen = 1,
989 .msg_name = &sa.sa,
990 .msg_namelen = sizeof(sa.in),
991 };
992
993 assert(m);
994 assert(fd >= 0);
995 assert(destination);
996 assert(port > 0);
997 assert(p);
998
999 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1000
1001 sa = (union sockaddr_union) {
1002 .in.sin_family = AF_INET,
1003 .in.sin_addr = *destination,
1004 .in.sin_port = htobe16(port),
1005 };
1006
1007 if (ifindex > 0) {
1008 struct cmsghdr *cmsg;
1009 struct in_pktinfo *pi;
1010
1011 mh.msg_control = &control;
1012 mh.msg_controllen = sizeof(control);
1013
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;
1018
1019 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
1020 pi->ipi_ifindex = ifindex;
1021
1022 if (source)
1023 pi->ipi_spec_dst = *source;
1024 }
1025
1026 return sendmsg_loop(fd, &mh, 0);
1027}
1028
1029static int manager_ipv6_send(
1030 Manager *m,
1031 int fd,
1032 int ifindex,
1033 const struct in6_addr *destination,
1034 uint16_t port,
1035 const struct in6_addr *source,
1036 DnsPacket *p) {
1037
1038 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1039 union sockaddr_union sa;
1040 struct iovec iov;
1041 struct msghdr mh = {
1042 .msg_iov = &iov,
1043 .msg_iovlen = 1,
1044 .msg_name = &sa.sa,
1045 .msg_namelen = sizeof(sa.in6),
1046 };
1047
1048 assert(m);
1049 assert(fd >= 0);
1050 assert(destination);
1051 assert(port > 0);
1052 assert(p);
1053
1054 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1055
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,
1061 };
1062
1063 if (ifindex > 0) {
1064 struct cmsghdr *cmsg;
1065 struct in6_pktinfo *pi;
1066
1067 mh.msg_control = &control;
1068 mh.msg_controllen = sizeof(control);
1069
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;
1074
1075 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1076 pi->ipi6_ifindex = ifindex;
1077
1078 if (source)
1079 pi->ipi6_addr = *source;
1080 }
1081
1082 return sendmsg_loop(fd, &mh, 0);
1083}
1084
1085static int dns_question_to_json(DnsQuestion *q, JsonVariant **ret) {
1086 _cleanup_(json_variant_unrefp) JsonVariant *l = NULL;
1087 DnsResourceKey *key;
1088 int r;
1089
1090 assert(ret);
1091
1092 DNS_QUESTION_FOREACH(key, q) {
1093 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1094
1095 r = dns_resource_key_to_json(key, &v);
1096 if (r < 0)
1097 return r;
1098
1099 r = json_variant_append_array(&l, v);
1100 if (r < 0)
1101 return r;
1102 }
1103
1104 *ret = TAKE_PTR(l);
1105 return 0;
1106}
1107
1108int manager_monitor_send(
1109 Manager *m,
1110 int state,
1111 int rcode,
1112 int error,
1113 DnsQuestion *question_idna,
1114 DnsQuestion *question_utf8,
1115 DnsQuestion *collected_questions,
1116 DnsAnswer *answer) {
1117
1118 _cleanup_(json_variant_unrefp) JsonVariant *jquestion = NULL, *jcollected_questions = NULL, *janswer = NULL;
1119 _cleanup_(dns_question_unrefp) DnsQuestion *merged = NULL;
1120 Varlink *connection;
1121 DnsAnswerItem *rri;
1122 int r;
1123
1124 assert(m);
1125
1126 if (set_isempty(m->varlink_subscription))
1127 return 0;
1128
1129 /* Merge both questions format into one */
1130 r = dns_question_merge(question_idna, question_utf8, &merged);
1131 if (r < 0)
1132 return log_error_errno(r, "Failed to merge UTF8/IDNA questions: %m");
1133
1134 /* Convert the current primary question to JSON */
1135 r = dns_question_to_json(merged, &jquestion);
1136 if (r < 0)
1137 return log_error_errno(r, "Failed to convert question to JSON: %m");
1138
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);
1141 if (r < 0)
1142 return log_error_errno(r, "Failed to convert question to JSON: %m");
1143
1144 DNS_ANSWER_FOREACH_ITEM(rri, answer) {
1145 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *w = NULL;
1146
1147 r = dns_resource_record_to_json(rri->rr, &v);
1148 if (r < 0)
1149 return log_error_errno(r, "Failed to convert answer resource record to JSON: %m");
1150
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 */
1152 if (r < 0)
1153 return log_error_errno(r, "Failed to generate RR wire format: %m");
1154
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))));
1159 if (r < 0)
1160 return log_error_errno(r, "Failed to make answer RR object: %m");
1161
1162 r = json_variant_append_array(&janswer, w);
1163 if (r < 0)
1164 return log_debug_errno(r, "Failed to append notification entry to array: %m");
1165 }
1166
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))));
1175 if (r < 0)
1176 log_debug_errno(r, "Failed to send monitor event, ignoring: %m");
1177 }
1178
1179 return 0;
1180}
1181
1182int manager_send(
1183 Manager *m,
1184 int fd,
1185 int ifindex,
1186 int family,
1187 const union in_addr_union *destination,
1188 uint16_t port,
1189 const union in_addr_union *source,
1190 DnsPacket *p) {
1191
1192 assert(m);
1193 assert(fd >= 0);
1194 assert(destination);
1195 assert(port > 0);
1196 assert(p);
1197
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",
1201 DNS_PACKET_ID(p),
1202 ifindex, af_to_name(family),
1203 p->size);
1204
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);
1209
1210 return -EAFNOSUPPORT;
1211}
1212
1213uint32_t manager_find_mtu(Manager *m) {
1214 uint32_t mtu = 0;
1215 Link *l;
1216
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 */
1219
1220 HASHMAP_FOREACH(l, m->links) {
1221 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1222 if (!l->addresses)
1223 continue;
1224
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))
1229 continue;
1230
1231 if (mtu <= 0 || l->mtu < mtu)
1232 mtu = l->mtu;
1233 }
1234
1235 if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1236 return 1500;
1237
1238 return mtu;
1239}
1240
1241int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1242 LinkAddress *a;
1243
1244 assert(m);
1245
1246 if (!IN_SET(family, AF_INET, AF_INET6))
1247 return 0;
1248
1249 if (!in_addr)
1250 return 0;
1251
1252 a = manager_find_link_address(m, family, in_addr);
1253 if (a)
1254 return a->link->ifindex;
1255
1256 return 0;
1257}
1258
1259void manager_refresh_rrs(Manager *m) {
1260 Link *l;
1261 DnssdService *s;
1262
1263 assert(m);
1264
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);
1269
1270 HASHMAP_FOREACH(l, m->links)
1271 link_add_rrs(l, true);
1272
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);
1277
1278 HASHMAP_FOREACH(l, m->links)
1279 link_add_rrs(l, false);
1280}
1281
1282static int manager_next_random_name(const char *old, char **ret_new) {
1283 const char *p;
1284 uint64_t u, a;
1285 char *n;
1286
1287 p = strchr(old, 0);
1288 assert(p);
1289
1290 while (p > old) {
1291 if (!ascii_isdigit(p[-1]))
1292 break;
1293
1294 p--;
1295 }
1296
1297 if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1298 u = 1;
1299
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
1305 * value 1..10 */
1306
1307 random_bytes(&a, sizeof(a));
1308 u += 1 + a % 10;
1309
1310 if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1311 return -ENOMEM;
1312
1313 *ret_new = n;
1314
1315 return 0;
1316}
1317
1318int manager_next_hostname(Manager *m) {
1319 _cleanup_free_ char *h = NULL, *k = NULL;
1320 int r;
1321
1322 assert(m);
1323
1324 r = manager_next_random_name(m->llmnr_hostname, &h);
1325 if (r < 0)
1326 return r;
1327
1328 r = dns_name_concat(h, "local", 0, &k);
1329 if (r < 0)
1330 return r;
1331
1332 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1333
1334 free_and_replace(m->llmnr_hostname, h);
1335 free_and_replace(m->mdns_hostname, k);
1336
1337 manager_refresh_rrs(m);
1338 (void) manager_send_changed(m, "LLMNRHostname");
1339
1340 return 0;
1341}
1342
1343LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1344 Link *l;
1345
1346 assert(m);
1347
1348 if (!IN_SET(family, AF_INET, AF_INET6))
1349 return NULL;
1350
1351 if (!in_addr)
1352 return NULL;
1353
1354 HASHMAP_FOREACH(l, m->links) {
1355 LinkAddress *a;
1356
1357 a = link_find_address(l, family, in_addr);
1358 if (a)
1359 return a;
1360 }
1361
1362 return NULL;
1363}
1364
1365bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1366 assert(m);
1367 assert(p);
1368
1369 /* Let's see if this packet comes from an IP address we have on any local interface */
1370
1371 return !!manager_find_link_address(m, p->family, &p->sender);
1372}
1373
1374bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1375 DnsTransaction *t;
1376
1377 assert(m);
1378 assert(p);
1379
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. */
1382
1383 t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1384 if (!t)
1385 return false;
1386
1387 return t->sent && dns_packet_equal(t->sent, p);
1388}
1389
1390DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1391 Link *l;
1392
1393 assert(m);
1394 assert(p);
1395
1396 l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1397 if (!l)
1398 return NULL;
1399
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;
1406
1407 break;
1408
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;
1414
1415 break;
1416
1417 default:
1418 break;
1419 }
1420
1421 return NULL;
1422}
1423
1424void manager_verify_all(Manager *m) {
1425 assert(m);
1426
1427 LIST_FOREACH(scopes, s, m->dns_scopes)
1428 dns_zone_verify_all(&s->zone);
1429}
1430
1431int manager_is_own_hostname(Manager *m, const char *name) {
1432 int r;
1433
1434 assert(m);
1435 assert(name);
1436
1437 if (m->llmnr_hostname) {
1438 r = dns_name_equal(name, m->llmnr_hostname);
1439 if (r != 0)
1440 return r;
1441 }
1442
1443 if (m->mdns_hostname) {
1444 r = dns_name_equal(name, m->mdns_hostname);
1445 if (r != 0)
1446 return r;
1447 }
1448
1449 if (m->full_hostname)
1450 return dns_name_equal(name, m->full_hostname);
1451
1452 return 0;
1453}
1454
1455int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1456 Link *l;
1457 int r;
1458
1459 assert(m);
1460 assert(dns);
1461
1462 r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1463 if (r < 0)
1464 return r;
1465
1466 /* First add the system-wide servers and domains */
1467 LIST_FOREACH(servers, s, m->dns_servers) {
1468 r = ordered_set_put(*dns, s);
1469 if (r == -EEXIST)
1470 continue;
1471 if (r < 0)
1472 return r;
1473 }
1474
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);
1479 if (r == -EEXIST)
1480 continue;
1481 if (r < 0)
1482 return r;
1483 }
1484 }
1485
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);
1490 if (r == -EEXIST)
1491 continue;
1492 if (r < 0)
1493 return r;
1494 }
1495 }
1496
1497 return 0;
1498}
1499
1500/* filter_route is a tri-state:
1501 * < 0: no filtering
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
1504 */
1505int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1506 Link *l;
1507 int r;
1508
1509 assert(m);
1510 assert(domains);
1511
1512 r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1513 if (r < 0)
1514 return r;
1515
1516 LIST_FOREACH(domains, d, m->search_domains) {
1517
1518 if (filter_route >= 0 &&
1519 d->route_only != !!filter_route)
1520 continue;
1521
1522 r = ordered_set_put(*domains, d->name);
1523 if (r == -EEXIST)
1524 continue;
1525 if (r < 0)
1526 return r;
1527 }
1528
1529 HASHMAP_FOREACH(l, m->links) {
1530
1531 LIST_FOREACH(domains, d, l->search_domains) {
1532
1533 if (filter_route >= 0 &&
1534 d->route_only != !!filter_route)
1535 continue;
1536
1537 r = ordered_set_put(*domains, d->name);
1538 if (r == -EEXIST)
1539 continue;
1540 if (r < 0)
1541 return r;
1542 }
1543 }
1544
1545 return 0;
1546}
1547
1548DnssecMode manager_get_dnssec_mode(Manager *m) {
1549 assert(m);
1550
1551 if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1552 return m->dnssec_mode;
1553
1554 return DNSSEC_NO;
1555}
1556
1557bool manager_dnssec_supported(Manager *m) {
1558 DnsServer *server;
1559 Link *l;
1560
1561 assert(m);
1562
1563 if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1564 return false;
1565
1566 server = manager_get_dns_server(m);
1567 if (server && !dns_server_dnssec_supported(server))
1568 return false;
1569
1570 HASHMAP_FOREACH(l, m->links)
1571 if (!link_dnssec_supported(l))
1572 return false;
1573
1574 return true;
1575}
1576
1577DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1578 assert(m);
1579
1580 if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1581 return m->dns_over_tls_mode;
1582
1583 return DNS_OVER_TLS_NO;
1584}
1585
1586void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1587
1588 assert(verdict >= 0);
1589 assert(verdict < _DNSSEC_VERDICT_MAX);
1590
1591 if (DEBUG_LOGGING) {
1592 char s[DNS_RESOURCE_KEY_STRING_MAX];
1593
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));
1597 }
1598
1599 m->n_dnssec_verdict[verdict]++;
1600}
1601
1602bool manager_routable(Manager *m) {
1603 Link *l;
1604
1605 assert(m);
1606
1607 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1608
1609 HASHMAP_FOREACH(l, m->links)
1610 if (link_relevant(l, AF_UNSPEC, false))
1611 return true;
1612
1613 return false;
1614}
1615
1616void manager_flush_caches(Manager *m, int log_level) {
1617 assert(m);
1618
1619 LIST_FOREACH(scopes, scope, m->dns_scopes)
1620 dns_cache_flush(&scope->cache);
1621
1622 log_full(log_level, "Flushed all caches.");
1623}
1624
1625void manager_reset_server_features(Manager *m) {
1626 Link *l;
1627
1628 dns_server_reset_features_all(m->dns_servers);
1629 dns_server_reset_features_all(m->fallback_dns_servers);
1630
1631 HASHMAP_FOREACH(l, m->links)
1632 dns_server_reset_features_all(l->dns_servers);
1633
1634 log_info("Resetting learnt feature levels on all servers.");
1635}
1636
1637void manager_cleanup_saved_user(Manager *m) {
1638 _cleanup_closedir_ DIR *d = NULL;
1639
1640 assert(m);
1641
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. */
1645
1646 d = opendir("/run/systemd/resolve/netif/");
1647 if (!d) {
1648 if (errno == ENOENT)
1649 return;
1650
1651 log_warning_errno(errno, "Failed to open interface directory: %m");
1652 return;
1653 }
1654
1655 FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1656 _cleanup_free_ char *p = NULL;
1657 int ifindex;
1658 Link *l;
1659
1660 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1661 continue;
1662
1663 if (dot_or_dot_dot(de->d_name))
1664 continue;
1665
1666 ifindex = parse_ifindex(de->d_name);
1667 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1668 goto rm;
1669
1670 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1671 if (!l) /* link vanished */
1672 goto rm;
1673
1674 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1675 goto rm;
1676
1677 continue;
1678
1679 rm:
1680 p = path_join("/run/systemd/resolve/netif", de->d_name);
1681 if (!p) {
1682 log_oom();
1683 return;
1684 }
1685
1686 (void) unlink(p);
1687 }
1688}
1689
1690bool manager_next_dnssd_names(Manager *m) {
1691 DnssdService *s;
1692 bool tried = false;
1693 int r;
1694
1695 assert(m);
1696
1697 HASHMAP_FOREACH(s, m->dnssd_services) {
1698 _cleanup_free_ char * new_name = NULL;
1699
1700 if (!s->withdrawn)
1701 continue;
1702
1703 r = manager_next_random_name(s->name_template, &new_name);
1704 if (r < 0) {
1705 log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1706 continue;
1707 }
1708
1709 free_and_replace(s->name_template, new_name);
1710
1711 s->withdrawn = false;
1712
1713 tried = true;
1714 }
1715
1716 if (tried)
1717 manager_refresh_rrs(m);
1718
1719 return tried;
1720}
1721
1722bool manager_server_is_stub(Manager *m, DnsServer *s) {
1723 DnsStubListenerExtra *l;
1724
1725 assert(m);
1726 assert(s);
1727
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)
1733 return true;
1734
1735 /* Main reason to call this is to check server data against the extra listeners, and filter things
1736 * out. */
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))
1741 return true;
1742
1743 return false;
1744}
1745
1746int socket_disable_pmtud(int fd, int af) {
1747 int r;
1748
1749 assert(fd >= 0);
1750
1751 if (af == AF_UNSPEC) {
1752 af = socket_get_family(fd);
1753 if (af < 0)
1754 return af;
1755 }
1756
1757 switch (af) {
1758
1759 case AF_INET: {
1760 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1761 * PMTU forgery vulnerabilities.
1762 *
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
1766 * discovery.
1767 *
1768 * This helps mitigating the PMTUD vulnerability described here:
1769 *
1770 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1771 *
1772 * Similar logic is in place in most DNS servers.
1773 *
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.
1779 */
1780
1781 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1782 if (r < 0)
1783 return r;
1784
1785 return 0;
1786 }
1787
1788 case AF_INET6: {
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. */
1793
1794 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1795 if (r < 0)
1796 return r;
1797
1798 return 0;
1799 }
1800
1801 default:
1802 return -EAFNOSUPPORT;
1803 }
1804}
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