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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 "memstream-util.h"
23#include "missing_network.h"
24#include "missing_socket.h"
25#include "netlink-util.h"
26#include "ordered-set.h"
27#include "parse-util.h"
28#include "random-util.h"
29#include "resolved-bus.h"
30#include "resolved-conf.h"
31#include "resolved-dns-stub.h"
32#include "resolved-dnssd.h"
33#include "resolved-etc-hosts.h"
34#include "resolved-llmnr.h"
35#include "resolved-manager.h"
36#include "resolved-mdns.h"
37#include "resolved-resolv-conf.h"
38#include "resolved-util.h"
39#include "resolved-varlink.h"
40#include "socket-util.h"
41#include "string-table.h"
42#include "string-util.h"
43#include "utf8.h"
44
45#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
46
47static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
48 Manager *m = ASSERT_PTR(userdata);
49 uint16_t type;
50 Link *l;
51 int ifindex, r;
52
53 assert(rtnl);
54 assert(mm);
55
56 r = sd_netlink_message_get_type(mm, &type);
57 if (r < 0)
58 goto fail;
59
60 r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
61 if (r < 0)
62 goto fail;
63
64 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
65
66 switch (type) {
67
68 case RTM_NEWLINK:{
69 bool is_new = !l;
70
71 if (!l) {
72 r = link_new(m, &l, ifindex);
73 if (r < 0)
74 goto fail;
75 }
76
77 r = link_process_rtnl(l, mm);
78 if (r < 0)
79 goto fail;
80
81 r = link_update(l);
82 if (r < 0)
83 goto fail;
84
85 if (is_new)
86 log_debug("Found new link %i/%s", ifindex, l->ifname);
87
88 break;
89 }
90
91 case RTM_DELLINK:
92 if (l) {
93 log_debug("Removing link %i/%s", l->ifindex, l->ifname);
94 link_remove_user(l);
95 link_free(l);
96 }
97
98 break;
99 }
100
101 return 0;
102
103fail:
104 log_warning_errno(r, "Failed to process RTNL link message: %m");
105 return 0;
106}
107
108static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
109 Manager *m = ASSERT_PTR(userdata);
110 union in_addr_union address, broadcast = {};
111 uint16_t type;
112 int r, ifindex, family;
113 LinkAddress *a;
114 Link *l;
115
116 assert(rtnl);
117 assert(mm);
118
119 r = sd_netlink_message_get_type(mm, &type);
120 if (r < 0)
121 goto fail;
122
123 r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
124 if (r < 0)
125 goto fail;
126
127 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
128 if (!l)
129 return 0;
130
131 r = sd_rtnl_message_addr_get_family(mm, &family);
132 if (r < 0)
133 goto fail;
134
135 switch (family) {
136
137 case AF_INET:
138 sd_netlink_message_read_in_addr(mm, IFA_BROADCAST, &broadcast.in);
139 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
140 if (r < 0) {
141 r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
142 if (r < 0)
143 goto fail;
144 }
145
146 break;
147
148 case AF_INET6:
149 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
150 if (r < 0) {
151 r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
152 if (r < 0)
153 goto fail;
154 }
155
156 break;
157
158 default:
159 return 0;
160 }
161
162 a = link_find_address(l, family, &address);
163
164 switch (type) {
165
166 case RTM_NEWADDR:
167
168 if (!a) {
169 r = link_address_new(l, &a, family, &address, &broadcast);
170 if (r < 0)
171 return r;
172 }
173
174 r = link_address_update_rtnl(a, mm);
175 if (r < 0)
176 return r;
177
178 break;
179
180 case RTM_DELADDR:
181 link_address_free(a);
182 break;
183 }
184
185 return 0;
186
187fail:
188 log_warning_errno(r, "Failed to process RTNL address message: %m");
189 return 0;
190}
191
192static int manager_rtnl_listen(Manager *m) {
193 _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
194 int r;
195
196 assert(m);
197
198 /* First, subscribe to interfaces coming and going */
199 r = sd_netlink_open(&m->rtnl);
200 if (r < 0)
201 return r;
202
203 r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
204 if (r < 0)
205 return r;
206
207 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
208 if (r < 0)
209 return r;
210
211 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
212 if (r < 0)
213 return r;
214
215 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
216 if (r < 0)
217 return r;
218
219 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
220 if (r < 0)
221 return r;
222
223 /* Then, enumerate all links */
224 r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
225 if (r < 0)
226 return r;
227
228 r = sd_netlink_message_set_request_dump(req, true);
229 if (r < 0)
230 return r;
231
232 r = sd_netlink_call(m->rtnl, req, 0, &reply);
233 if (r < 0)
234 return r;
235
236 for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
237 r = manager_process_link(m->rtnl, i, m);
238 if (r < 0)
239 return r;
240 }
241
242 req = sd_netlink_message_unref(req);
243 reply = sd_netlink_message_unref(reply);
244
245 /* Finally, enumerate all addresses, too */
246 r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
247 if (r < 0)
248 return r;
249
250 r = sd_netlink_message_set_request_dump(req, true);
251 if (r < 0)
252 return r;
253
254 r = sd_netlink_call(m->rtnl, req, 0, &reply);
255 if (r < 0)
256 return r;
257
258 for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
259 r = manager_process_address(m->rtnl, i, m);
260 if (r < 0)
261 return r;
262 }
263
264 return r;
265}
266
267static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
268 Manager *m = ASSERT_PTR(userdata);
269 Link *l;
270 int r;
271
272 sd_network_monitor_flush(m->network_monitor);
273
274 HASHMAP_FOREACH(l, m->links) {
275 r = link_update(l);
276 if (r < 0)
277 log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
278 }
279
280 (void) manager_write_resolv_conf(m);
281 (void) manager_send_changed(m, "DNS");
282
283 return 0;
284}
285
286static int manager_network_monitor_listen(Manager *m) {
287 int r, fd, events;
288
289 assert(m);
290
291 r = sd_network_monitor_new(&m->network_monitor, NULL);
292 if (r < 0)
293 return r;
294
295 fd = sd_network_monitor_get_fd(m->network_monitor);
296 if (fd < 0)
297 return fd;
298
299 events = sd_network_monitor_get_events(m->network_monitor);
300 if (events < 0)
301 return events;
302
303 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
304 if (r < 0)
305 return r;
306
307 r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
308 if (r < 0)
309 return r;
310
311 (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
312
313 return 0;
314}
315
316static int manager_clock_change_listen(Manager *m);
317
318static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
319 Manager *m = ASSERT_PTR(userdata);
320
321 /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
322 * the system clock into consideration, and if the clock changes the old validations might have been
323 * wrong. Let's redo all validation with the new, correct time.
324 *
325 * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
326 * we might be connected to a different network now without this being visible in a dropped link
327 * carrier or so.) */
328
329 log_info("Clock change detected. Flushing caches.");
330 manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
331
332 /* The clock change timerfd is unusable after it triggered once, create a new one. */
333 return manager_clock_change_listen(m);
334}
335
336static int manager_clock_change_listen(Manager *m) {
337 int r;
338
339 assert(m);
340
341 m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
342
343 r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
344 if (r < 0)
345 return log_error_errno(r, "Failed to create clock change event source: %m");
346
347 return 0;
348}
349
350static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
351 _cleanup_free_ char *h = NULL, *n = NULL;
352 int r;
353
354 assert(full_hostname);
355 assert(llmnr_hostname);
356 assert(mdns_hostname);
357
358 r = resolve_system_hostname(&h, &n);
359 if (r < 0)
360 return r;
361
362 r = dns_name_concat(n, "local", 0, mdns_hostname);
363 if (r < 0)
364 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
365
366 *llmnr_hostname = TAKE_PTR(n);
367 *full_hostname = TAKE_PTR(h);
368
369 return 0;
370}
371
372static char* fallback_hostname(void) {
373
374 /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
375 * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
376 * instead. */
377
378 _cleanup_free_ char *n = get_default_hostname();
379 if (!n)
380 return NULL;
381
382 if (is_localhost(n))
383 return strdup("linux");
384
385 return TAKE_PTR(n);
386}
387
388static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
389 _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
390 char label[DNS_LABEL_MAX];
391 const char *p;
392 int r;
393
394 assert(full_hostname);
395 assert(llmnr_hostname);
396 assert(mdns_hostname);
397
398 p = h = fallback_hostname();
399 if (!h)
400 return log_oom();
401
402 r = dns_label_unescape(&p, label, sizeof label, 0);
403 if (r < 0)
404 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
405
406 assert(r > 0); /* The fallback hostname must have at least one label */
407
408 r = dns_label_escape_new(label, r, &n);
409 if (r < 0)
410 return log_error_errno(r, "Failed to escape fallback hostname: %m");
411
412 r = dns_name_concat(n, "local", 0, &m);
413 if (r < 0)
414 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
415
416 *llmnr_hostname = TAKE_PTR(n);
417 *mdns_hostname = TAKE_PTR(m);
418 *full_hostname = TAKE_PTR(h);
419
420 return 0;
421}
422
423static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
424 _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
425 Manager *m = ASSERT_PTR(userdata);
426 bool llmnr_hostname_changed;
427 int r;
428
429 r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
430 if (r < 0) {
431 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
432 return 0; /* ignore invalid hostnames */
433 }
434
435 llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
436 if (streq(full_hostname, m->full_hostname) &&
437 !llmnr_hostname_changed &&
438 streq(mdns_hostname, m->mdns_hostname))
439 return 0;
440
441 log_info("System hostname changed to '%s'.", full_hostname);
442
443 free_and_replace(m->full_hostname, full_hostname);
444 free_and_replace(m->llmnr_hostname, llmnr_hostname);
445 free_and_replace(m->mdns_hostname, mdns_hostname);
446
447 manager_refresh_rrs(m);
448 (void) manager_send_changed(m, "LLMNRHostname");
449
450 return 0;
451}
452
453static int manager_watch_hostname(Manager *m) {
454 int r;
455
456 assert(m);
457
458 m->hostname_fd = open("/proc/sys/kernel/hostname",
459 O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
460 if (m->hostname_fd < 0) {
461 log_warning_errno(errno, "Failed to watch hostname: %m");
462 return 0;
463 }
464
465 r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
466 if (r < 0) {
467 if (r == -EPERM)
468 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
469 m->hostname_fd = safe_close(m->hostname_fd);
470 else
471 return log_error_errno(r, "Failed to add hostname event source: %m");
472 }
473
474 (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
475
476 r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
477 if (r < 0) {
478 _cleanup_free_ char *d = NULL;
479
480 d = fallback_hostname();
481 if (!d)
482 return log_oom();
483
484 log_info("Defaulting to hostname '%s'.", d);
485
486 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
487 if (r < 0)
488 return r;
489 } else
490 log_info("Using system hostname '%s'.", m->full_hostname);
491
492 return 0;
493}
494
495static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
496 _cleanup_(memstream_done) MemStream ms = {};
497 Manager *m = ASSERT_PTR(userdata);
498 Link *l;
499 FILE *f;
500
501 assert(s);
502 assert(si);
503
504 f = memstream_init(&ms);
505 if (!f)
506 return log_oom();
507
508 LIST_FOREACH(scopes, scope, m->dns_scopes)
509 dns_scope_dump(scope, f);
510
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);
518
519 return memstream_dump(LOG_INFO, &ms);
520}
521
522static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
523 Manager *m = ASSERT_PTR(userdata);
524
525 assert(s);
526 assert(si);
527
528 manager_flush_caches(m, LOG_INFO);
529
530 return 0;
531}
532
533static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
534 Manager *m = ASSERT_PTR(userdata);
535
536 assert(s);
537 assert(si);
538
539 manager_reset_server_features(m);
540 return 0;
541}
542
543static int manager_memory_pressure(sd_event_source *s, void *userdata) {
544 Manager *m = ASSERT_PTR(userdata);
545
546 log_info("Under memory pressure, flushing caches.");
547
548 manager_flush_caches(m, LOG_INFO);
549 sd_event_trim_memory();
550
551 return 0;
552}
553
554static int manager_memory_pressure_listen(Manager *m) {
555 int r;
556
557 assert(m);
558
559 r = sd_event_add_memory_pressure(m->event, NULL, manager_memory_pressure, m);
560 if (r < 0)
561 log_full_errno(ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || (r == -EHOSTDOWN )? LOG_DEBUG : LOG_NOTICE, r,
562 "Failed to install memory pressure event source, ignoring: %m");
563
564 return 0;
565}
566
567int manager_new(Manager **ret) {
568 _cleanup_(manager_freep) Manager *m = NULL;
569 int r;
570
571 assert(ret);
572
573 m = new(Manager, 1);
574 if (!m)
575 return -ENOMEM;
576
577 *m = (Manager) {
578 .llmnr_ipv4_udp_fd = -EBADF,
579 .llmnr_ipv6_udp_fd = -EBADF,
580 .llmnr_ipv4_tcp_fd = -EBADF,
581 .llmnr_ipv6_tcp_fd = -EBADF,
582 .mdns_ipv4_fd = -EBADF,
583 .mdns_ipv6_fd = -EBADF,
584 .hostname_fd = -EBADF,
585
586 .llmnr_support = DEFAULT_LLMNR_MODE,
587 .mdns_support = DEFAULT_MDNS_MODE,
588 .dnssec_mode = DEFAULT_DNSSEC_MODE,
589 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
590 .enable_cache = DNS_CACHE_MODE_YES,
591 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
592 .read_resolv_conf = true,
593 .need_builtin_fallbacks = true,
594 .etc_hosts_last = USEC_INFINITY,
595 .read_etc_hosts = true,
596
597 .sigrtmin18_info.memory_pressure_handler = manager_memory_pressure,
598 .sigrtmin18_info.memory_pressure_userdata = m,
599 };
600
601 r = dns_trust_anchor_load(&m->trust_anchor);
602 if (r < 0)
603 return r;
604
605 r = manager_parse_config_file(m);
606 if (r < 0)
607 log_warning_errno(r, "Failed to parse configuration file: %m");
608
609#if ENABLE_DNS_OVER_TLS
610 r = dnstls_manager_init(m);
611 if (r < 0)
612 return r;
613#endif
614
615 r = sd_event_default(&m->event);
616 if (r < 0)
617 return r;
618
619 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
620 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
621
622 (void) sd_event_set_watchdog(m->event, true);
623
624 r = manager_watch_hostname(m);
625 if (r < 0)
626 return r;
627
628 r = dnssd_load(m);
629 if (r < 0)
630 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
631
632 r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
633 if (r < 0)
634 return r;
635
636 r = manager_network_monitor_listen(m);
637 if (r < 0)
638 return r;
639
640 r = manager_rtnl_listen(m);
641 if (r < 0)
642 return r;
643
644 r = manager_clock_change_listen(m);
645 if (r < 0)
646 return r;
647
648 r = manager_memory_pressure_listen(m);
649 if (r < 0)
650 return r;
651
652 r = manager_connect_bus(m);
653 if (r < 0)
654 return r;
655
656 (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
657 (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
658 (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
659 (void) sd_event_add_signal(m->event, NULL, SIGRTMIN+18, sigrtmin18_handler, &m->sigrtmin18_info);
660
661 manager_cleanup_saved_user(m);
662
663 *ret = TAKE_PTR(m);
664
665 return 0;
666}
667
668int manager_start(Manager *m) {
669 int r;
670
671 assert(m);
672
673 r = manager_dns_stub_start(m);
674 if (r < 0)
675 return r;
676
677 r = manager_varlink_init(m);
678 if (r < 0)
679 return r;
680
681 return 0;
682}
683
684Manager *manager_free(Manager *m) {
685 Link *l;
686 DnssdService *s;
687
688 if (!m)
689 return NULL;
690
691 dns_server_unlink_all(m->dns_servers);
692 dns_server_unlink_all(m->fallback_dns_servers);
693 dns_search_domain_unlink_all(m->search_domains);
694
695 while ((l = hashmap_first(m->links)))
696 link_free(l);
697
698 while (m->dns_queries)
699 dns_query_free(m->dns_queries);
700
701 m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
702
703 dns_scope_free(m->unicast_scope);
704
705 /* At this point only orphaned streams should remain. All others should have been freed already by their
706 * owners */
707 while (m->dns_streams)
708 dns_stream_unref(m->dns_streams);
709
710#if ENABLE_DNS_OVER_TLS
711 dnstls_manager_free(m);
712#endif
713
714 hashmap_free(m->links);
715 hashmap_free(m->dns_transactions);
716
717 sd_event_source_unref(m->network_event_source);
718 sd_network_monitor_unref(m->network_monitor);
719
720 sd_netlink_unref(m->rtnl);
721 sd_event_source_unref(m->rtnl_event_source);
722 sd_event_source_unref(m->clock_change_event_source);
723
724 manager_llmnr_stop(m);
725 manager_mdns_stop(m);
726 manager_dns_stub_stop(m);
727 manager_varlink_done(m);
728
729 manager_socket_graveyard_clear(m);
730
731 ordered_set_free(m->dns_extra_stub_listeners);
732
733 bus_verify_polkit_async_registry_free(m->polkit_registry);
734
735 sd_bus_flush_close_unref(m->bus);
736
737 sd_event_source_unref(m->sigusr1_event_source);
738 sd_event_source_unref(m->sigusr2_event_source);
739 sd_event_source_unref(m->sigrtmin1_event_source);
740
741 dns_resource_key_unref(m->llmnr_host_ipv4_key);
742 dns_resource_key_unref(m->llmnr_host_ipv6_key);
743 dns_resource_key_unref(m->mdns_host_ipv4_key);
744 dns_resource_key_unref(m->mdns_host_ipv6_key);
745
746 sd_event_source_unref(m->hostname_event_source);
747 safe_close(m->hostname_fd);
748
749 sd_event_unref(m->event);
750
751 free(m->full_hostname);
752 free(m->llmnr_hostname);
753 free(m->mdns_hostname);
754
755 while ((s = hashmap_first(m->dnssd_services)))
756 dnssd_service_free(s);
757 hashmap_free(m->dnssd_services);
758
759 dns_trust_anchor_flush(&m->trust_anchor);
760 manager_etc_hosts_flush(m);
761
762 return mfree(m);
763}
764
765int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
766 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
767 CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
768 + CMSG_SPACE(int) /* ttl/hoplimit */
769 + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
770 union sockaddr_union sa;
771 struct iovec iov;
772 struct msghdr mh = {
773 .msg_name = &sa.sa,
774 .msg_namelen = sizeof(sa),
775 .msg_iov = &iov,
776 .msg_iovlen = 1,
777 .msg_control = &control,
778 .msg_controllen = sizeof(control),
779 };
780 struct cmsghdr *cmsg;
781 ssize_t ms, l;
782 int r;
783
784 assert(m);
785 assert(fd >= 0);
786 assert(ret);
787
788 ms = next_datagram_size_fd(fd);
789 if (ms < 0)
790 return ms;
791
792 r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
793 if (r < 0)
794 return r;
795
796 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
797
798 l = recvmsg_safe(fd, &mh, 0);
799 if (ERRNO_IS_NEG_TRANSIENT(l))
800 return 0;
801 if (l <= 0)
802 return l;
803
804 assert(!(mh.msg_flags & MSG_TRUNC));
805
806 p->size = (size_t) l;
807
808 p->family = sa.sa.sa_family;
809 p->ipproto = IPPROTO_UDP;
810 if (p->family == AF_INET) {
811 p->sender.in = sa.in.sin_addr;
812 p->sender_port = be16toh(sa.in.sin_port);
813 } else if (p->family == AF_INET6) {
814 p->sender.in6 = sa.in6.sin6_addr;
815 p->sender_port = be16toh(sa.in6.sin6_port);
816 p->ifindex = sa.in6.sin6_scope_id;
817 } else
818 return -EAFNOSUPPORT;
819
820 p->timestamp = now(CLOCK_BOOTTIME);
821
822 CMSG_FOREACH(cmsg, &mh) {
823
824 if (cmsg->cmsg_level == IPPROTO_IPV6) {
825 assert(p->family == AF_INET6);
826
827 switch (cmsg->cmsg_type) {
828
829 case IPV6_PKTINFO: {
830 struct in6_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
831
832 if (p->ifindex <= 0)
833 p->ifindex = i->ipi6_ifindex;
834
835 p->destination.in6 = i->ipi6_addr;
836 break;
837 }
838
839 case IPV6_HOPLIMIT:
840 p->ttl = *CMSG_TYPED_DATA(cmsg, int);
841 break;
842
843 case IPV6_RECVFRAGSIZE:
844 p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
845 break;
846 }
847 } else if (cmsg->cmsg_level == IPPROTO_IP) {
848 assert(p->family == AF_INET);
849
850 switch (cmsg->cmsg_type) {
851
852 case IP_PKTINFO: {
853 struct in_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
854
855 if (p->ifindex <= 0)
856 p->ifindex = i->ipi_ifindex;
857
858 p->destination.in = i->ipi_addr;
859 break;
860 }
861
862 case IP_TTL:
863 p->ttl = *CMSG_TYPED_DATA(cmsg, int);
864 break;
865
866 case IP_RECVFRAGSIZE:
867 p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
868 break;
869 }
870 }
871 }
872
873 /* The Linux kernel sets the interface index to the loopback
874 * device if the packet came from the local host since it
875 * avoids the routing table in such a case. Let's unset the
876 * interface index in such a case. */
877 if (p->ifindex == LOOPBACK_IFINDEX)
878 p->ifindex = 0;
879
880 if (protocol != DNS_PROTOCOL_DNS) {
881 /* If we don't know the interface index still, we look for the
882 * first local interface with a matching address. Yuck! */
883 if (p->ifindex <= 0)
884 p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
885 }
886
887 log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
888 dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize,
889 IN_ADDR_TO_STRING(p->family, &p->sender),
890 IN_ADDR_TO_STRING(p->family, &p->destination));
891
892 *ret = TAKE_PTR(p);
893 return 1;
894}
895
896static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
897 usec_t end;
898 int r;
899
900 assert(fd >= 0);
901 assert(mh);
902
903 end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
904
905 for (;;) {
906 if (sendmsg(fd, mh, flags) >= 0)
907 return 0;
908 if (errno == EINTR)
909 continue;
910 if (errno != EAGAIN)
911 return -errno;
912
913 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
914 if (ERRNO_IS_NEG_TRANSIENT(r))
915 continue;
916 if (r < 0)
917 return r;
918 if (r == 0)
919 return -ETIMEDOUT;
920 }
921}
922
923static int write_loop(int fd, void *message, size_t length) {
924 usec_t end;
925 int r;
926
927 assert(fd >= 0);
928 assert(message);
929
930 end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
931
932 for (;;) {
933 if (write(fd, message, length) >= 0)
934 return 0;
935 if (errno == EINTR)
936 continue;
937 if (errno != EAGAIN)
938 return -errno;
939
940 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
941 if (ERRNO_IS_NEG_TRANSIENT(r))
942 continue;
943 if (r < 0)
944 return r;
945 if (r == 0)
946 return -ETIMEDOUT;
947 }
948}
949
950int manager_write(Manager *m, int fd, DnsPacket *p) {
951 int r;
952
953 log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
954 DNS_PACKET_TC(p) ? "truncated (!) " : "",
955 DNS_PACKET_QR(p) ? "response" : "query",
956 DNS_PACKET_ID(p),
957 p->size);
958
959 r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
960 if (r < 0)
961 return r;
962
963 return 0;
964}
965
966static int manager_ipv4_send(
967 Manager *m,
968 int fd,
969 int ifindex,
970 const struct in_addr *destination,
971 uint16_t port,
972 const struct in_addr *source,
973 DnsPacket *p) {
974
975 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
976 union sockaddr_union sa;
977 struct iovec iov;
978 struct msghdr mh = {
979 .msg_iov = &iov,
980 .msg_iovlen = 1,
981 .msg_name = &sa.sa,
982 .msg_namelen = sizeof(sa.in),
983 };
984
985 assert(m);
986 assert(fd >= 0);
987 assert(destination);
988 assert(port > 0);
989 assert(p);
990
991 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
992
993 sa = (union sockaddr_union) {
994 .in.sin_family = AF_INET,
995 .in.sin_addr = *destination,
996 .in.sin_port = htobe16(port),
997 };
998
999 if (ifindex > 0) {
1000 struct cmsghdr *cmsg;
1001 struct in_pktinfo *pi;
1002
1003 mh.msg_control = &control;
1004 mh.msg_controllen = sizeof(control);
1005
1006 cmsg = CMSG_FIRSTHDR(&mh);
1007 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
1008 cmsg->cmsg_level = IPPROTO_IP;
1009 cmsg->cmsg_type = IP_PKTINFO;
1010
1011 pi = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
1012 pi->ipi_ifindex = ifindex;
1013
1014 if (source)
1015 pi->ipi_spec_dst = *source;
1016 }
1017
1018 return sendmsg_loop(fd, &mh, 0);
1019}
1020
1021static int manager_ipv6_send(
1022 Manager *m,
1023 int fd,
1024 int ifindex,
1025 const struct in6_addr *destination,
1026 uint16_t port,
1027 const struct in6_addr *source,
1028 DnsPacket *p) {
1029
1030 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1031 union sockaddr_union sa;
1032 struct iovec iov;
1033 struct msghdr mh = {
1034 .msg_iov = &iov,
1035 .msg_iovlen = 1,
1036 .msg_name = &sa.sa,
1037 .msg_namelen = sizeof(sa.in6),
1038 };
1039
1040 assert(m);
1041 assert(fd >= 0);
1042 assert(destination);
1043 assert(port > 0);
1044 assert(p);
1045
1046 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1047
1048 sa = (union sockaddr_union) {
1049 .in6.sin6_family = AF_INET6,
1050 .in6.sin6_addr = *destination,
1051 .in6.sin6_port = htobe16(port),
1052 .in6.sin6_scope_id = ifindex,
1053 };
1054
1055 if (ifindex > 0) {
1056 struct cmsghdr *cmsg;
1057 struct in6_pktinfo *pi;
1058
1059 mh.msg_control = &control;
1060 mh.msg_controllen = sizeof(control);
1061
1062 cmsg = CMSG_FIRSTHDR(&mh);
1063 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1064 cmsg->cmsg_level = IPPROTO_IPV6;
1065 cmsg->cmsg_type = IPV6_PKTINFO;
1066
1067 pi = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
1068 pi->ipi6_ifindex = ifindex;
1069
1070 if (source)
1071 pi->ipi6_addr = *source;
1072 }
1073
1074 return sendmsg_loop(fd, &mh, 0);
1075}
1076
1077static int dns_question_to_json(DnsQuestion *q, JsonVariant **ret) {
1078 _cleanup_(json_variant_unrefp) JsonVariant *l = NULL;
1079 DnsResourceKey *key;
1080 int r;
1081
1082 assert(ret);
1083
1084 DNS_QUESTION_FOREACH(key, q) {
1085 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1086
1087 r = dns_resource_key_to_json(key, &v);
1088 if (r < 0)
1089 return r;
1090
1091 r = json_variant_append_array(&l, v);
1092 if (r < 0)
1093 return r;
1094 }
1095
1096 *ret = TAKE_PTR(l);
1097 return 0;
1098}
1099
1100int manager_monitor_send(
1101 Manager *m,
1102 int state,
1103 int rcode,
1104 int error,
1105 DnsQuestion *question_idna,
1106 DnsQuestion *question_utf8,
1107 DnsQuestion *collected_questions,
1108 DnsAnswer *answer) {
1109
1110 _cleanup_(json_variant_unrefp) JsonVariant *jquestion = NULL, *jcollected_questions = NULL, *janswer = NULL;
1111 _cleanup_(dns_question_unrefp) DnsQuestion *merged = NULL;
1112 Varlink *connection;
1113 DnsAnswerItem *rri;
1114 int r;
1115
1116 assert(m);
1117
1118 if (set_isempty(m->varlink_subscription))
1119 return 0;
1120
1121 /* Merge both questions format into one */
1122 r = dns_question_merge(question_idna, question_utf8, &merged);
1123 if (r < 0)
1124 return log_error_errno(r, "Failed to merge UTF8/IDNA questions: %m");
1125
1126 /* Convert the current primary question to JSON */
1127 r = dns_question_to_json(merged, &jquestion);
1128 if (r < 0)
1129 return log_error_errno(r, "Failed to convert question to JSON: %m");
1130
1131 /* Generate a JSON array of the questions preceding the current one in the CNAME chain */
1132 r = dns_question_to_json(collected_questions, &jcollected_questions);
1133 if (r < 0)
1134 return log_error_errno(r, "Failed to convert question to JSON: %m");
1135
1136 DNS_ANSWER_FOREACH_ITEM(rri, answer) {
1137 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1138
1139 r = dns_resource_record_to_json(rri->rr, &v);
1140 if (r < 0)
1141 return log_error_errno(r, "Failed to convert answer resource record to JSON: %m");
1142
1143 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 */
1144 if (r < 0)
1145 return log_error_errno(r, "Failed to generate RR wire format: %m");
1146
1147 r = json_variant_append_arrayb(
1148 &janswer,
1149 JSON_BUILD_OBJECT(
1150 JSON_BUILD_PAIR_CONDITION(v, "rr", JSON_BUILD_VARIANT(v)),
1151 JSON_BUILD_PAIR("raw", JSON_BUILD_BASE64(rri->rr->wire_format, rri->rr->wire_format_size)),
1152 JSON_BUILD_PAIR_CONDITION(rri->ifindex > 0, "ifindex", JSON_BUILD_INTEGER(rri->ifindex))));
1153 if (r < 0)
1154 return log_debug_errno(r, "Failed to append notification entry to array: %m");
1155 }
1156
1157 SET_FOREACH(connection, m->varlink_subscription) {
1158 r = varlink_notifyb(connection,
1159 JSON_BUILD_OBJECT(JSON_BUILD_PAIR("state", JSON_BUILD_STRING(dns_transaction_state_to_string(state))),
1160 JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_RCODE_FAILURE, "rcode", JSON_BUILD_INTEGER(rcode)),
1161 JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_ERRNO, "errno", JSON_BUILD_INTEGER(error)),
1162 JSON_BUILD_PAIR("question", JSON_BUILD_VARIANT(jquestion)),
1163 JSON_BUILD_PAIR_CONDITION(jcollected_questions, "collectedQuestions", JSON_BUILD_VARIANT(jcollected_questions)),
1164 JSON_BUILD_PAIR_CONDITION(janswer, "answer", JSON_BUILD_VARIANT(janswer))));
1165 if (r < 0)
1166 log_debug_errno(r, "Failed to send monitor event, ignoring: %m");
1167 }
1168
1169 return 0;
1170}
1171
1172int manager_send(
1173 Manager *m,
1174 int fd,
1175 int ifindex,
1176 int family,
1177 const union in_addr_union *destination,
1178 uint16_t port,
1179 const union in_addr_union *source,
1180 DnsPacket *p) {
1181
1182 assert(m);
1183 assert(fd >= 0);
1184 assert(destination);
1185 assert(port > 0);
1186 assert(p);
1187
1188 log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1189 DNS_PACKET_TC(p) ? "truncated (!) " : "",
1190 DNS_PACKET_QR(p) ? "response" : "query",
1191 DNS_PACKET_ID(p),
1192 ifindex, af_to_name(family),
1193 p->size);
1194
1195 if (family == AF_INET)
1196 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1197 if (family == AF_INET6)
1198 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1199
1200 return -EAFNOSUPPORT;
1201}
1202
1203uint32_t manager_find_mtu(Manager *m) {
1204 uint32_t mtu = 0;
1205 Link *l;
1206
1207 /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1208 * works on all interfaces we know of that have an IP address associated */
1209
1210 HASHMAP_FOREACH(l, m->links) {
1211 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1212 if (!l->addresses)
1213 continue;
1214
1215 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1216 * let's ignore this link. */
1217 if (l->mtu < MIN(UDP4_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE,
1218 UDP6_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE))
1219 continue;
1220
1221 if (mtu <= 0 || l->mtu < mtu)
1222 mtu = l->mtu;
1223 }
1224
1225 if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1226 return 1500;
1227
1228 return mtu;
1229}
1230
1231int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1232 LinkAddress *a;
1233
1234 assert(m);
1235
1236 if (!IN_SET(family, AF_INET, AF_INET6))
1237 return 0;
1238
1239 if (!in_addr)
1240 return 0;
1241
1242 a = manager_find_link_address(m, family, in_addr);
1243 if (a)
1244 return a->link->ifindex;
1245
1246 return 0;
1247}
1248
1249void manager_refresh_rrs(Manager *m) {
1250 Link *l;
1251 DnssdService *s;
1252
1253 assert(m);
1254
1255 m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1256 m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1257 m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1258 m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1259
1260 HASHMAP_FOREACH(l, m->links)
1261 link_add_rrs(l, true);
1262
1263 if (m->mdns_support == RESOLVE_SUPPORT_YES)
1264 HASHMAP_FOREACH(s, m->dnssd_services)
1265 if (dnssd_update_rrs(s) < 0)
1266 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1267
1268 HASHMAP_FOREACH(l, m->links)
1269 link_add_rrs(l, false);
1270}
1271
1272static int manager_next_random_name(const char *old, char **ret_new) {
1273 const char *p;
1274 uint64_t u, a;
1275 char *n;
1276
1277 p = strchr(old, 0);
1278 assert(p);
1279
1280 while (p > old) {
1281 if (!ascii_isdigit(p[-1]))
1282 break;
1283
1284 p--;
1285 }
1286
1287 if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1288 u = 1;
1289
1290 /* Add a random number to the old value. This way we can avoid
1291 * that two hosts pick the same hostname, win on IPv4 and lose
1292 * on IPv6 (or vice versa), and pick the same hostname
1293 * replacement hostname, ad infinitum. We still want the
1294 * numbers to go up monotonically, hence we just add a random
1295 * value 1..10 */
1296
1297 random_bytes(&a, sizeof(a));
1298 u += 1 + a % 10;
1299
1300 if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1301 return -ENOMEM;
1302
1303 *ret_new = n;
1304
1305 return 0;
1306}
1307
1308int manager_next_hostname(Manager *m) {
1309 _cleanup_free_ char *h = NULL, *k = NULL;
1310 int r;
1311
1312 assert(m);
1313
1314 r = manager_next_random_name(m->llmnr_hostname, &h);
1315 if (r < 0)
1316 return r;
1317
1318 r = dns_name_concat(h, "local", 0, &k);
1319 if (r < 0)
1320 return r;
1321
1322 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1323
1324 free_and_replace(m->llmnr_hostname, h);
1325 free_and_replace(m->mdns_hostname, k);
1326
1327 manager_refresh_rrs(m);
1328 (void) manager_send_changed(m, "LLMNRHostname");
1329
1330 return 0;
1331}
1332
1333LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1334 Link *l;
1335
1336 assert(m);
1337
1338 if (!IN_SET(family, AF_INET, AF_INET6))
1339 return NULL;
1340
1341 if (!in_addr)
1342 return NULL;
1343
1344 HASHMAP_FOREACH(l, m->links) {
1345 LinkAddress *a;
1346
1347 a = link_find_address(l, family, in_addr);
1348 if (a)
1349 return a;
1350 }
1351
1352 return NULL;
1353}
1354
1355bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1356 assert(m);
1357 assert(p);
1358
1359 /* Let's see if this packet comes from an IP address we have on any local interface */
1360
1361 return !!manager_find_link_address(m, p->family, &p->sender);
1362}
1363
1364bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1365 DnsTransaction *t;
1366
1367 assert(m);
1368 assert(p);
1369
1370 /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1371 * one we just got. If so, it's almost definitely a packet loop of some kind. */
1372
1373 t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1374 if (!t)
1375 return false;
1376
1377 return t->sent && dns_packet_equal(t->sent, p);
1378}
1379
1380DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1381 Link *l;
1382
1383 assert(m);
1384 assert(p);
1385
1386 l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1387 if (!l)
1388 return NULL;
1389
1390 switch (p->protocol) {
1391 case DNS_PROTOCOL_LLMNR:
1392 if (p->family == AF_INET)
1393 return l->llmnr_ipv4_scope;
1394 else if (p->family == AF_INET6)
1395 return l->llmnr_ipv6_scope;
1396
1397 break;
1398
1399 case DNS_PROTOCOL_MDNS:
1400 if (p->family == AF_INET)
1401 return l->mdns_ipv4_scope;
1402 else if (p->family == AF_INET6)
1403 return l->mdns_ipv6_scope;
1404
1405 break;
1406
1407 default:
1408 break;
1409 }
1410
1411 return NULL;
1412}
1413
1414void manager_verify_all(Manager *m) {
1415 assert(m);
1416
1417 LIST_FOREACH(scopes, s, m->dns_scopes)
1418 dns_zone_verify_all(&s->zone);
1419}
1420
1421int manager_is_own_hostname(Manager *m, const char *name) {
1422 int r;
1423
1424 assert(m);
1425 assert(name);
1426
1427 if (m->llmnr_hostname) {
1428 r = dns_name_equal(name, m->llmnr_hostname);
1429 if (r != 0)
1430 return r;
1431 }
1432
1433 if (m->mdns_hostname) {
1434 r = dns_name_equal(name, m->mdns_hostname);
1435 if (r != 0)
1436 return r;
1437 }
1438
1439 if (m->full_hostname)
1440 return dns_name_equal(name, m->full_hostname);
1441
1442 return 0;
1443}
1444
1445int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1446 Link *l;
1447 int r;
1448
1449 assert(m);
1450 assert(dns);
1451
1452 r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1453 if (r < 0)
1454 return r;
1455
1456 /* First add the system-wide servers and domains */
1457 LIST_FOREACH(servers, s, m->dns_servers) {
1458 r = ordered_set_put(*dns, s);
1459 if (r == -EEXIST)
1460 continue;
1461 if (r < 0)
1462 return r;
1463 }
1464
1465 /* Then, add the per-link servers */
1466 HASHMAP_FOREACH(l, m->links) {
1467 LIST_FOREACH(servers, s, l->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
1476 /* If we found nothing, add the fallback servers */
1477 if (ordered_set_isempty(*dns)) {
1478 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1479 r = ordered_set_put(*dns, s);
1480 if (r == -EEXIST)
1481 continue;
1482 if (r < 0)
1483 return r;
1484 }
1485 }
1486
1487 return 0;
1488}
1489
1490/* filter_route is a tri-state:
1491 * < 0: no filtering
1492 * = 0 or false: return only domains which should be used for searching
1493 * > 0 or true: return only domains which are for routing only
1494 */
1495int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1496 Link *l;
1497 int r;
1498
1499 assert(m);
1500 assert(domains);
1501
1502 r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1503 if (r < 0)
1504 return r;
1505
1506 LIST_FOREACH(domains, d, m->search_domains) {
1507
1508 if (filter_route >= 0 &&
1509 d->route_only != !!filter_route)
1510 continue;
1511
1512 r = ordered_set_put(*domains, d->name);
1513 if (r == -EEXIST)
1514 continue;
1515 if (r < 0)
1516 return r;
1517 }
1518
1519 HASHMAP_FOREACH(l, m->links) {
1520
1521 LIST_FOREACH(domains, d, l->search_domains) {
1522
1523 if (filter_route >= 0 &&
1524 d->route_only != !!filter_route)
1525 continue;
1526
1527 r = ordered_set_put(*domains, d->name);
1528 if (r == -EEXIST)
1529 continue;
1530 if (r < 0)
1531 return r;
1532 }
1533 }
1534
1535 return 0;
1536}
1537
1538DnssecMode manager_get_dnssec_mode(Manager *m) {
1539 assert(m);
1540
1541 if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1542 return m->dnssec_mode;
1543
1544 return DNSSEC_NO;
1545}
1546
1547bool manager_dnssec_supported(Manager *m) {
1548 DnsServer *server;
1549 Link *l;
1550
1551 assert(m);
1552
1553 if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1554 return false;
1555
1556 server = manager_get_dns_server(m);
1557 if (server && !dns_server_dnssec_supported(server))
1558 return false;
1559
1560 HASHMAP_FOREACH(l, m->links)
1561 if (!link_dnssec_supported(l))
1562 return false;
1563
1564 return true;
1565}
1566
1567DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1568 assert(m);
1569
1570 if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1571 return m->dns_over_tls_mode;
1572
1573 return DNS_OVER_TLS_NO;
1574}
1575
1576void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1577
1578 assert(verdict >= 0);
1579 assert(verdict < _DNSSEC_VERDICT_MAX);
1580
1581 if (DEBUG_LOGGING) {
1582 char s[DNS_RESOURCE_KEY_STRING_MAX];
1583
1584 log_debug("Found verdict for lookup %s: %s",
1585 dns_resource_key_to_string(key, s, sizeof s),
1586 dnssec_verdict_to_string(verdict));
1587 }
1588
1589 m->n_dnssec_verdict[verdict]++;
1590}
1591
1592bool manager_routable(Manager *m) {
1593 Link *l;
1594
1595 assert(m);
1596
1597 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1598
1599 HASHMAP_FOREACH(l, m->links)
1600 if (link_relevant(l, AF_UNSPEC, false))
1601 return true;
1602
1603 return false;
1604}
1605
1606void manager_flush_caches(Manager *m, int log_level) {
1607 assert(m);
1608
1609 LIST_FOREACH(scopes, scope, m->dns_scopes)
1610 dns_cache_flush(&scope->cache);
1611
1612 log_full(log_level, "Flushed all caches.");
1613}
1614
1615void manager_reset_server_features(Manager *m) {
1616 Link *l;
1617
1618 dns_server_reset_features_all(m->dns_servers);
1619 dns_server_reset_features_all(m->fallback_dns_servers);
1620
1621 HASHMAP_FOREACH(l, m->links)
1622 dns_server_reset_features_all(l->dns_servers);
1623
1624 log_info("Resetting learnt feature levels on all servers.");
1625}
1626
1627void manager_cleanup_saved_user(Manager *m) {
1628 _cleanup_closedir_ DIR *d = NULL;
1629
1630 assert(m);
1631
1632 /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1633 * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1634 * be restarted without losing this data. */
1635
1636 d = opendir("/run/systemd/resolve/netif/");
1637 if (!d) {
1638 if (errno == ENOENT)
1639 return;
1640
1641 log_warning_errno(errno, "Failed to open interface directory: %m");
1642 return;
1643 }
1644
1645 FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1646 _cleanup_free_ char *p = NULL;
1647 int ifindex;
1648 Link *l;
1649
1650 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1651 continue;
1652
1653 if (dot_or_dot_dot(de->d_name))
1654 continue;
1655
1656 ifindex = parse_ifindex(de->d_name);
1657 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1658 goto rm;
1659
1660 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1661 if (!l) /* link vanished */
1662 goto rm;
1663
1664 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1665 goto rm;
1666
1667 continue;
1668
1669 rm:
1670 p = path_join("/run/systemd/resolve/netif", de->d_name);
1671 if (!p) {
1672 log_oom();
1673 return;
1674 }
1675
1676 (void) unlink(p);
1677 }
1678}
1679
1680bool manager_next_dnssd_names(Manager *m) {
1681 DnssdService *s;
1682 bool tried = false;
1683 int r;
1684
1685 assert(m);
1686
1687 HASHMAP_FOREACH(s, m->dnssd_services) {
1688 _cleanup_free_ char * new_name = NULL;
1689
1690 if (!s->withdrawn)
1691 continue;
1692
1693 r = manager_next_random_name(s->name_template, &new_name);
1694 if (r < 0) {
1695 log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1696 continue;
1697 }
1698
1699 free_and_replace(s->name_template, new_name);
1700
1701 s->withdrawn = false;
1702
1703 tried = true;
1704 }
1705
1706 if (tried)
1707 manager_refresh_rrs(m);
1708
1709 return tried;
1710}
1711
1712bool manager_server_is_stub(Manager *m, DnsServer *s) {
1713 DnsStubListenerExtra *l;
1714
1715 assert(m);
1716 assert(s);
1717
1718 /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1719 * extra careful, and check here again */
1720 if (s->family == AF_INET &&
1721 s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1722 dns_server_port(s) == 53)
1723 return true;
1724
1725 /* Main reason to call this is to check server data against the extra listeners, and filter things
1726 * out. */
1727 ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1728 if (s->family == l->family &&
1729 in_addr_equal(s->family, &s->address, &l->address) &&
1730 dns_server_port(s) == dns_stub_listener_extra_port(l))
1731 return true;
1732
1733 return false;
1734}
1735
1736int socket_disable_pmtud(int fd, int af) {
1737 int r;
1738
1739 assert(fd >= 0);
1740
1741 if (af == AF_UNSPEC) {
1742 af = socket_get_family(fd);
1743 if (af < 0)
1744 return af;
1745 }
1746
1747 switch (af) {
1748
1749 case AF_INET: {
1750 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1751 * PMTU forgery vulnerabilities.
1752 *
1753 * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1754 * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1755 * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1756 * discovery.
1757 *
1758 * This helps mitigating the PMTUD vulnerability described here:
1759 *
1760 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1761 *
1762 * Similar logic is in place in most DNS servers.
1763 *
1764 * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1765 * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1766 * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1767 * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1768 * fragments seen — and if we need larger packets always go to TCP.
1769 */
1770
1771 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1772 if (r < 0)
1773 return r;
1774
1775 return 0;
1776 }
1777
1778 case AF_INET6: {
1779 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1780 * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1781 * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1782 * because there's nothing that could be fragmented further anymore. */
1783
1784 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1785 if (r < 0)
1786 return r;
1787
1788 return 0;
1789 }
1790
1791 default:
1792 return -EAFNOSUPPORT;
1793 }
1794}
1795
1796int dns_manager_dump_statistics_json(Manager *m, JsonVariant **ret) {
1797 uint64_t size = 0, hit = 0, miss = 0;
1798
1799 assert(m);
1800 assert(ret);
1801
1802 LIST_FOREACH(scopes, s, m->dns_scopes) {
1803 size += dns_cache_size(&s->cache);
1804 hit += s->cache.n_hit;
1805 miss += s->cache.n_miss;
1806 }
1807
1808 return json_build(ret,
1809 JSON_BUILD_OBJECT(
1810 JSON_BUILD_PAIR("transactions", JSON_BUILD_OBJECT(
1811 JSON_BUILD_PAIR_UNSIGNED("currentTransactions", hashmap_size(m->dns_transactions)),
1812 JSON_BUILD_PAIR_UNSIGNED("totalTransactions", m->n_transactions_total),
1813 JSON_BUILD_PAIR_UNSIGNED("totalTimeouts", m->n_timeouts_total),
1814 JSON_BUILD_PAIR_UNSIGNED("totalTimeoutsServedStale", m->n_timeouts_served_stale_total),
1815 JSON_BUILD_PAIR_UNSIGNED("totalFailedResponses", m->n_failure_responses_total),
1816 JSON_BUILD_PAIR_UNSIGNED("totalFailedResponsesServedStale", m->n_failure_responses_served_stale_total)
1817 )),
1818 JSON_BUILD_PAIR("cache", JSON_BUILD_OBJECT(
1819 JSON_BUILD_PAIR_UNSIGNED("size", size),
1820 JSON_BUILD_PAIR_UNSIGNED("hits", hit),
1821 JSON_BUILD_PAIR_UNSIGNED("misses", miss)
1822 )),
1823 JSON_BUILD_PAIR("dnssec", JSON_BUILD_OBJECT(
1824 JSON_BUILD_PAIR_UNSIGNED("secure", m->n_dnssec_verdict[DNSSEC_SECURE]),
1825 JSON_BUILD_PAIR_UNSIGNED("insecure", m->n_dnssec_verdict[DNSSEC_INSECURE]),
1826 JSON_BUILD_PAIR_UNSIGNED("bogus", m->n_dnssec_verdict[DNSSEC_BOGUS]),
1827 JSON_BUILD_PAIR_UNSIGNED("indeterminate", m->n_dnssec_verdict[DNSSEC_INDETERMINATE])
1828 ))));
1829}
1830
1831void dns_manager_reset_statistics(Manager *m) {
1832
1833 assert(m);
1834
1835 LIST_FOREACH(scopes, s, m->dns_scopes)
1836 s->cache.n_hit = s->cache.n_miss = 0;
1837
1838 m->n_transactions_total = 0;
1839 m->n_timeouts_total = 0;
1840 m->n_timeouts_served_stale_total = 0;
1841 m->n_failure_responses_total = 0;
1842 m->n_failure_responses_served_stale_total = 0;
1843 zero(m->n_dnssec_verdict);
1844}
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