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Merge pull request #18679 from keszybz/rfkill-size-leniency
[thirdparty/systemd.git] / src / resolve / resolved-manager.c
... / ...
CommitLineData
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 "fd-util.h"
17#include "fileio.h"
18#include "hostname-util.h"
19#include "idn-util.h"
20#include "io-util.h"
21#include "missing_network.h"
22#include "missing_socket.h"
23#include "netlink-util.h"
24#include "ordered-set.h"
25#include "parse-util.h"
26#include "random-util.h"
27#include "resolved-bus.h"
28#include "resolved-conf.h"
29#include "resolved-dns-stub.h"
30#include "resolved-dnssd.h"
31#include "resolved-etc-hosts.h"
32#include "resolved-llmnr.h"
33#include "resolved-manager.h"
34#include "resolved-mdns.h"
35#include "resolved-resolv-conf.h"
36#include "resolved-varlink.h"
37#include "socket-util.h"
38#include "string-table.h"
39#include "string-util.h"
40#include "utf8.h"
41
42#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
43
44static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
45 Manager *m = userdata;
46 uint16_t type;
47 Link *l;
48 int ifindex, r;
49
50 assert(rtnl);
51 assert(m);
52 assert(mm);
53
54 r = sd_netlink_message_get_type(mm, &type);
55 if (r < 0)
56 goto fail;
57
58 r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
59 if (r < 0)
60 goto fail;
61
62 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
63
64 switch (type) {
65
66 case RTM_NEWLINK:{
67 bool is_new = !l;
68
69 if (!l) {
70 r = link_new(m, &l, ifindex);
71 if (r < 0)
72 goto fail;
73 }
74
75 r = link_process_rtnl(l, mm);
76 if (r < 0)
77 goto fail;
78
79 r = link_update(l);
80 if (r < 0)
81 goto fail;
82
83 if (is_new)
84 log_debug("Found new link %i/%s", ifindex, l->ifname);
85
86 break;
87 }
88
89 case RTM_DELLINK:
90 if (l) {
91 log_debug("Removing link %i/%s", l->ifindex, l->ifname);
92 link_remove_user(l);
93 link_free(l);
94 }
95
96 break;
97 }
98
99 return 0;
100
101fail:
102 log_warning_errno(r, "Failed to process RTNL link message: %m");
103 return 0;
104}
105
106static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
107 Manager *m = userdata;
108 union in_addr_union address;
109 uint16_t type;
110 int r, ifindex, family;
111 LinkAddress *a;
112 Link *l;
113
114 assert(rtnl);
115 assert(mm);
116 assert(m);
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 sd_netlink_message *i;
193 int r;
194
195 assert(m);
196
197 /* First, subscribe to interfaces coming and going */
198 r = sd_netlink_open(&m->rtnl);
199 if (r < 0)
200 return r;
201
202 r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
203 if (r < 0)
204 return r;
205
206 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
207 if (r < 0)
208 return r;
209
210 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
211 if (r < 0)
212 return r;
213
214 r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
215 if (r < 0)
216 return r;
217
218 r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
219 if (r < 0)
220 return r;
221
222 /* Then, enumerate all links */
223 r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
224 if (r < 0)
225 return r;
226
227 r = sd_netlink_message_request_dump(req, true);
228 if (r < 0)
229 return r;
230
231 r = sd_netlink_call(m->rtnl, req, 0, &reply);
232 if (r < 0)
233 return r;
234
235 for (i = reply; i; i = sd_netlink_message_next(i)) {
236 r = manager_process_link(m->rtnl, i, m);
237 if (r < 0)
238 return r;
239 }
240
241 req = sd_netlink_message_unref(req);
242 reply = sd_netlink_message_unref(reply);
243
244 /* Finally, enumerate all addresses, too */
245 r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
246 if (r < 0)
247 return r;
248
249 r = sd_netlink_message_request_dump(req, true);
250 if (r < 0)
251 return r;
252
253 r = sd_netlink_call(m->rtnl, req, 0, &reply);
254 if (r < 0)
255 return r;
256
257 for (i = reply; i; i = sd_netlink_message_next(i)) {
258 r = manager_process_address(m->rtnl, i, m);
259 if (r < 0)
260 return r;
261 }
262
263 return r;
264}
265
266static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
267 Manager *m = userdata;
268 Link *l;
269 int r;
270
271 assert(m);
272
273 sd_network_monitor_flush(m->network_monitor);
274
275 HASHMAP_FOREACH(l, m->links) {
276 r = link_update(l);
277 if (r < 0)
278 log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
279 }
280
281 (void) manager_write_resolv_conf(m);
282 (void) manager_send_changed(m, "DNS");
283
284 return 0;
285}
286
287static int manager_network_monitor_listen(Manager *m) {
288 int r, fd, events;
289
290 assert(m);
291
292 r = sd_network_monitor_new(&m->network_monitor, NULL);
293 if (r < 0)
294 return r;
295
296 fd = sd_network_monitor_get_fd(m->network_monitor);
297 if (fd < 0)
298 return fd;
299
300 events = sd_network_monitor_get_events(m->network_monitor);
301 if (events < 0)
302 return events;
303
304 r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
305 if (r < 0)
306 return r;
307
308 r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
309 if (r < 0)
310 return r;
311
312 (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
313
314 return 0;
315}
316
317static int manager_clock_change_listen(Manager *m);
318
319static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
320 Manager *m = userdata;
321
322 assert(m);
323
324 /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
325 * the system clock into consideration, and if the clock changes the old validations might have been
326 * wrong. Let's redo all validation with the new, correct time.
327 *
328 * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
329 * we might be connected to a different network now without this being visible in a dropped link
330 * carrier or so.) */
331
332 log_info("Clock change detected. Flushing caches.");
333 manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
334
335 /* The clock change timerfd is unusable after it triggered once, create a new one. */
336 return manager_clock_change_listen(m);
337}
338
339static int manager_clock_change_listen(Manager *m) {
340 _cleanup_close_ int fd = -1;
341 int r;
342
343 assert(m);
344
345 m->clock_change_event_source = sd_event_source_unref(m->clock_change_event_source);
346
347 fd = time_change_fd();
348 if (fd < 0)
349 return log_error_errno(fd, "Failed to allocate clock change timer fd: %m");
350
351 r = sd_event_add_io(m->event, &m->clock_change_event_source, fd, EPOLLIN, on_clock_change, m);
352 if (r < 0)
353 return log_error_errno(r, "Failed to create clock change event source: %m");
354
355 r = sd_event_source_set_io_fd_own(m->clock_change_event_source, true);
356 if (r < 0)
357 return log_error_errno(r, "Failed to pass ownership of clock fd to event source: %m");
358 TAKE_FD(fd);
359
360 (void) sd_event_source_set_description(m->clock_change_event_source, "clock-change");
361
362 return 0;
363}
364
365static int determine_hostname(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
366 _cleanup_free_ char *h = NULL, *n = NULL;
367#if HAVE_LIBIDN2
368 _cleanup_free_ char *utf8 = NULL;
369#elif HAVE_LIBIDN
370 int k;
371#endif
372 char label[DNS_LABEL_MAX];
373 const char *p, *decoded;
374 int r;
375
376 assert(full_hostname);
377 assert(llmnr_hostname);
378 assert(mdns_hostname);
379
380 /* Extract and normalize the first label of the locally configured hostname, and check it's not "localhost". */
381
382 r = gethostname_strict(&h);
383 if (r < 0)
384 return log_debug_errno(r, "Can't determine system hostname: %m");
385
386 p = h;
387 r = dns_label_unescape(&p, label, sizeof label, 0);
388 if (r < 0)
389 return log_error_errno(r, "Failed to unescape hostname: %m");
390 if (r == 0)
391 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
392 "Couldn't find a single label in hostname.");
393
394#if HAVE_LIBIDN || HAVE_LIBIDN2
395 r = dlopen_idn();
396 if (r < 0) {
397 log_debug_errno(r, "Failed to initialize IDN support, ignoring: %m");
398 decoded = label; /* no decoding */
399 } else
400#endif
401 {
402#if HAVE_LIBIDN2
403 r = sym_idn2_to_unicode_8z8z(label, &utf8, 0);
404 if (r != IDN2_OK)
405 return log_error_errno(SYNTHETIC_ERRNO(EUCLEAN),
406 "Failed to undo IDNA: %s", sym_idn2_strerror(r));
407 assert(utf8_is_valid(utf8));
408
409 r = strlen(utf8);
410 decoded = utf8;
411#elif HAVE_LIBIDN
412 k = dns_label_undo_idna(label, r, label, sizeof label);
413 if (k < 0)
414 return log_error_errno(k, "Failed to undo IDNA: %m");
415 if (k > 0)
416 r = k;
417
418 if (!utf8_is_valid(label))
419 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
420 "System hostname is not UTF-8 clean.");
421 decoded = label;
422#else
423 decoded = label; /* no decoding */
424#endif
425 }
426
427 r = dns_label_escape_new(decoded, r, &n);
428 if (r < 0)
429 return log_error_errno(r, "Failed to escape hostname: %m");
430
431 if (is_localhost(n))
432 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
433 "System hostname is 'localhost', ignoring.");
434
435 r = dns_name_concat(n, "local", 0, mdns_hostname);
436 if (r < 0)
437 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
438
439 *llmnr_hostname = TAKE_PTR(n);
440 *full_hostname = TAKE_PTR(h);
441
442 return 0;
443}
444
445static const char *fallback_hostname(void) {
446
447 /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it to be
448 * "localhost" even if that's the compiled in hostname. In this case, let's revert to "linux" instead. */
449
450 if (is_localhost(FALLBACK_HOSTNAME))
451 return "linux";
452
453 return FALLBACK_HOSTNAME;
454}
455
456static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
457 _cleanup_free_ char *n = NULL, *m = NULL;
458 char label[DNS_LABEL_MAX], *h;
459 const char *p;
460 int r;
461
462 assert(full_hostname);
463 assert(llmnr_hostname);
464 assert(mdns_hostname);
465
466 p = fallback_hostname();
467 r = dns_label_unescape(&p, label, sizeof label, 0);
468 if (r < 0)
469 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
470
471 assert(r > 0); /* The fallback hostname must have at least one label */
472
473 r = dns_label_escape_new(label, r, &n);
474 if (r < 0)
475 return log_error_errno(r, "Failed to escape fallback hostname: %m");
476
477 r = dns_name_concat(n, "local", 0, &m);
478 if (r < 0)
479 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
480
481 h = strdup(fallback_hostname());
482 if (!h)
483 return log_oom();
484
485 *llmnr_hostname = TAKE_PTR(n);
486 *mdns_hostname = TAKE_PTR(m);
487
488 *full_hostname = h;
489
490 return 0;
491}
492
493static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
494 _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
495 Manager *m = userdata;
496 bool llmnr_hostname_changed;
497 int r;
498
499 assert(m);
500
501 r = determine_hostname(&full_hostname, &llmnr_hostname, &mdns_hostname);
502 if (r < 0)
503 return 0; /* ignore invalid hostnames */
504
505 llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
506 if (streq(full_hostname, m->full_hostname) &&
507 !llmnr_hostname_changed &&
508 streq(mdns_hostname, m->mdns_hostname))
509 return 0;
510
511 log_info("System hostname changed to '%s'.", full_hostname);
512
513 free_and_replace(m->full_hostname, full_hostname);
514 free_and_replace(m->llmnr_hostname, llmnr_hostname);
515 free_and_replace(m->mdns_hostname, mdns_hostname);
516
517 manager_refresh_rrs(m);
518 (void) manager_send_changed(m, "LLMNRHostname");
519
520 return 0;
521}
522
523static int manager_watch_hostname(Manager *m) {
524 int r;
525
526 assert(m);
527
528 m->hostname_fd = open("/proc/sys/kernel/hostname",
529 O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
530 if (m->hostname_fd < 0) {
531 log_warning_errno(errno, "Failed to watch hostname: %m");
532 return 0;
533 }
534
535 r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
536 if (r < 0) {
537 if (r == -EPERM)
538 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
539 m->hostname_fd = safe_close(m->hostname_fd);
540 else
541 return log_error_errno(r, "Failed to add hostname event source: %m");
542 }
543
544 (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
545
546 r = determine_hostname(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
547 if (r < 0) {
548 log_info("Defaulting to hostname '%s'.", fallback_hostname());
549
550 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
551 if (r < 0)
552 return r;
553 } else
554 log_info("Using system hostname '%s'.", m->full_hostname);
555
556 return 0;
557}
558
559static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
560 _cleanup_free_ char *buffer = NULL;
561 _cleanup_fclose_ FILE *f = NULL;
562 Manager *m = userdata;
563 DnsServer *server;
564 size_t size = 0;
565 DnsScope *scope;
566 Link *l;
567
568 assert(s);
569 assert(si);
570 assert(m);
571
572 f = open_memstream_unlocked(&buffer, &size);
573 if (!f)
574 return log_oom();
575
576 LIST_FOREACH(scopes, scope, m->dns_scopes)
577 dns_scope_dump(scope, f);
578
579 LIST_FOREACH(servers, server, m->dns_servers)
580 dns_server_dump(server, f);
581 LIST_FOREACH(servers, server, m->fallback_dns_servers)
582 dns_server_dump(server, f);
583 HASHMAP_FOREACH(l, m->links)
584 LIST_FOREACH(servers, server, l->dns_servers)
585 dns_server_dump(server, f);
586
587 if (fflush_and_check(f) < 0)
588 return log_oom();
589
590 log_dump(LOG_INFO, buffer);
591 return 0;
592}
593
594static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
595 Manager *m = userdata;
596
597 assert(s);
598 assert(si);
599 assert(m);
600
601 manager_flush_caches(m, LOG_INFO);
602
603 return 0;
604}
605
606static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
607 Manager *m = userdata;
608
609 assert(s);
610 assert(si);
611 assert(m);
612
613 manager_reset_server_features(m);
614 return 0;
615}
616
617int manager_new(Manager **ret) {
618 _cleanup_(manager_freep) Manager *m = NULL;
619 int r;
620
621 assert(ret);
622
623 m = new(Manager, 1);
624 if (!m)
625 return -ENOMEM;
626
627 *m = (Manager) {
628 .llmnr_ipv4_udp_fd = -1,
629 .llmnr_ipv6_udp_fd = -1,
630 .llmnr_ipv4_tcp_fd = -1,
631 .llmnr_ipv6_tcp_fd = -1,
632 .mdns_ipv4_fd = -1,
633 .mdns_ipv6_fd = -1,
634 .hostname_fd = -1,
635
636 .llmnr_support = DEFAULT_LLMNR_MODE,
637 .mdns_support = DEFAULT_MDNS_MODE,
638 .dnssec_mode = DEFAULT_DNSSEC_MODE,
639 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
640 .enable_cache = DNS_CACHE_MODE_YES,
641 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
642 .read_resolv_conf = true,
643 .need_builtin_fallbacks = true,
644 .etc_hosts_last = USEC_INFINITY,
645 .read_etc_hosts = true,
646 };
647
648 r = dns_trust_anchor_load(&m->trust_anchor);
649 if (r < 0)
650 return r;
651
652 r = manager_parse_config_file(m);
653 if (r < 0)
654 log_warning_errno(r, "Failed to parse configuration file: %m");
655
656#if ENABLE_DNS_OVER_TLS
657 r = dnstls_manager_init(m);
658 if (r < 0)
659 return r;
660#endif
661
662 r = sd_event_default(&m->event);
663 if (r < 0)
664 return r;
665
666 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
667 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
668
669 (void) sd_event_set_watchdog(m->event, true);
670
671 r = manager_watch_hostname(m);
672 if (r < 0)
673 return r;
674
675 r = dnssd_load(m);
676 if (r < 0)
677 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
678
679 r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
680 if (r < 0)
681 return r;
682
683 r = manager_network_monitor_listen(m);
684 if (r < 0)
685 return r;
686
687 r = manager_rtnl_listen(m);
688 if (r < 0)
689 return r;
690
691 r = manager_clock_change_listen(m);
692 if (r < 0)
693 return r;
694
695 r = manager_connect_bus(m);
696 if (r < 0)
697 return r;
698
699 (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
700 (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
701 (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
702
703 manager_cleanup_saved_user(m);
704
705 *ret = TAKE_PTR(m);
706
707 return 0;
708}
709
710int manager_start(Manager *m) {
711 int r;
712
713 assert(m);
714
715 r = manager_dns_stub_start(m);
716 if (r < 0)
717 return r;
718
719 r = manager_varlink_init(m);
720 if (r < 0)
721 return r;
722
723 return 0;
724}
725
726Manager *manager_free(Manager *m) {
727 Link *l;
728 DnssdService *s;
729
730 if (!m)
731 return NULL;
732
733 dns_server_unlink_all(m->dns_servers);
734 dns_server_unlink_all(m->fallback_dns_servers);
735 dns_search_domain_unlink_all(m->search_domains);
736
737 while ((l = hashmap_first(m->links)))
738 link_free(l);
739
740 while (m->dns_queries)
741 dns_query_free(m->dns_queries);
742
743 m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
744
745 dns_scope_free(m->unicast_scope);
746
747 /* At this point only orphaned streams should remain. All others should have been freed already by their
748 * owners */
749 while (m->dns_streams)
750 dns_stream_unref(m->dns_streams);
751
752#if ENABLE_DNS_OVER_TLS
753 dnstls_manager_free(m);
754#endif
755
756 hashmap_free(m->links);
757 hashmap_free(m->dns_transactions);
758
759 sd_event_source_unref(m->network_event_source);
760 sd_network_monitor_unref(m->network_monitor);
761
762 sd_netlink_unref(m->rtnl);
763 sd_event_source_unref(m->rtnl_event_source);
764 sd_event_source_unref(m->clock_change_event_source);
765
766 manager_llmnr_stop(m);
767 manager_mdns_stop(m);
768 manager_dns_stub_stop(m);
769 manager_varlink_done(m);
770
771 manager_socket_graveyard_clear(m);
772
773 ordered_set_free(m->dns_extra_stub_listeners);
774
775 bus_verify_polkit_async_registry_free(m->polkit_registry);
776
777 sd_bus_flush_close_unref(m->bus);
778
779 sd_event_source_unref(m->sigusr1_event_source);
780 sd_event_source_unref(m->sigusr2_event_source);
781 sd_event_source_unref(m->sigrtmin1_event_source);
782
783 sd_event_unref(m->event);
784
785 dns_resource_key_unref(m->llmnr_host_ipv4_key);
786 dns_resource_key_unref(m->llmnr_host_ipv6_key);
787 dns_resource_key_unref(m->mdns_host_ipv4_key);
788 dns_resource_key_unref(m->mdns_host_ipv6_key);
789
790 sd_event_source_unref(m->hostname_event_source);
791 safe_close(m->hostname_fd);
792
793 free(m->full_hostname);
794 free(m->llmnr_hostname);
795 free(m->mdns_hostname);
796
797 while ((s = hashmap_first(m->dnssd_services)))
798 dnssd_service_free(s);
799 hashmap_free(m->dnssd_services);
800
801 dns_trust_anchor_flush(&m->trust_anchor);
802 manager_etc_hosts_flush(m);
803
804 return mfree(m);
805}
806
807int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
808 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
809 CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
810 + CMSG_SPACE(int) /* ttl/hoplimit */
811 + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
812 union sockaddr_union sa;
813 struct iovec iov;
814 struct msghdr mh = {
815 .msg_name = &sa.sa,
816 .msg_namelen = sizeof(sa),
817 .msg_iov = &iov,
818 .msg_iovlen = 1,
819 .msg_control = &control,
820 .msg_controllen = sizeof(control),
821 };
822 struct cmsghdr *cmsg;
823 ssize_t ms, l;
824 int r;
825
826 assert(m);
827 assert(fd >= 0);
828 assert(ret);
829
830 ms = next_datagram_size_fd(fd);
831 if (ms < 0)
832 return ms;
833
834 r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
835 if (r < 0)
836 return r;
837
838 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
839
840 l = recvmsg_safe(fd, &mh, 0);
841 if (IN_SET(l, -EAGAIN, -EINTR))
842 return 0;
843 if (l <= 0)
844 return l;
845
846 assert(!(mh.msg_flags & MSG_TRUNC));
847
848 p->size = (size_t) l;
849
850 p->family = sa.sa.sa_family;
851 p->ipproto = IPPROTO_UDP;
852 if (p->family == AF_INET) {
853 p->sender.in = sa.in.sin_addr;
854 p->sender_port = be16toh(sa.in.sin_port);
855 } else if (p->family == AF_INET6) {
856 p->sender.in6 = sa.in6.sin6_addr;
857 p->sender_port = be16toh(sa.in6.sin6_port);
858 p->ifindex = sa.in6.sin6_scope_id;
859 } else
860 return -EAFNOSUPPORT;
861
862 p->timestamp = now(clock_boottime_or_monotonic());
863
864 CMSG_FOREACH(cmsg, &mh) {
865
866 if (cmsg->cmsg_level == IPPROTO_IPV6) {
867 assert(p->family == AF_INET6);
868
869 switch (cmsg->cmsg_type) {
870
871 case IPV6_PKTINFO: {
872 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
873
874 if (p->ifindex <= 0)
875 p->ifindex = i->ipi6_ifindex;
876
877 p->destination.in6 = i->ipi6_addr;
878 break;
879 }
880
881 case IPV6_HOPLIMIT:
882 p->ttl = *(int *) CMSG_DATA(cmsg);
883 break;
884
885 case IPV6_RECVFRAGSIZE:
886 p->fragsize = *(int *) CMSG_DATA(cmsg);
887 break;
888 }
889 } else if (cmsg->cmsg_level == IPPROTO_IP) {
890 assert(p->family == AF_INET);
891
892 switch (cmsg->cmsg_type) {
893
894 case IP_PKTINFO: {
895 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
896
897 if (p->ifindex <= 0)
898 p->ifindex = i->ipi_ifindex;
899
900 p->destination.in = i->ipi_addr;
901 break;
902 }
903
904 case IP_TTL:
905 p->ttl = *(int *) CMSG_DATA(cmsg);
906 break;
907
908 case IP_RECVFRAGSIZE:
909 p->fragsize = *(int *) CMSG_DATA(cmsg);
910 break;
911 }
912 }
913 }
914
915 /* The Linux kernel sets the interface index to the loopback
916 * device if the packet came from the local host since it
917 * avoids the routing table in such a case. Let's unset the
918 * interface index in such a case. */
919 if (p->ifindex == LOOPBACK_IFINDEX)
920 p->ifindex = 0;
921
922 if (protocol != DNS_PROTOCOL_DNS) {
923 /* If we don't know the interface index still, we look for the
924 * first local interface with a matching address. Yuck! */
925 if (p->ifindex <= 0)
926 p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
927 }
928
929 *ret = TAKE_PTR(p);
930
931 return 1;
932}
933
934static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
935 int r;
936
937 assert(fd >= 0);
938 assert(mh);
939
940 for (;;) {
941 if (sendmsg(fd, mh, flags) >= 0)
942 return 0;
943
944 if (errno == EINTR)
945 continue;
946
947 if (errno != EAGAIN)
948 return -errno;
949
950 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
951 if (r < 0)
952 return r;
953 if (r == 0)
954 return -ETIMEDOUT;
955 }
956}
957
958static int write_loop(int fd, void *message, size_t length) {
959 int r;
960
961 assert(fd >= 0);
962 assert(message);
963
964 for (;;) {
965 if (write(fd, message, length) >= 0)
966 return 0;
967
968 if (errno == EINTR)
969 continue;
970
971 if (errno != EAGAIN)
972 return -errno;
973
974 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
975 if (r < 0)
976 return r;
977 if (r == 0)
978 return -ETIMEDOUT;
979 }
980}
981
982int manager_write(Manager *m, int fd, DnsPacket *p) {
983 int r;
984
985 log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
986 DNS_PACKET_TC(p) ? "truncated (!) " : "",
987 DNS_PACKET_QR(p) ? "response" : "query",
988 DNS_PACKET_ID(p),
989 p->size);
990
991 r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
992 if (r < 0)
993 return r;
994
995 return 0;
996}
997
998static int manager_ipv4_send(
999 Manager *m,
1000 int fd,
1001 int ifindex,
1002 const struct in_addr *destination,
1003 uint16_t port,
1004 const struct in_addr *source,
1005 DnsPacket *p) {
1006
1007 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
1008 union sockaddr_union sa;
1009 struct iovec iov;
1010 struct msghdr mh = {
1011 .msg_iov = &iov,
1012 .msg_iovlen = 1,
1013 .msg_name = &sa.sa,
1014 .msg_namelen = sizeof(sa.in),
1015 };
1016
1017 assert(m);
1018 assert(fd >= 0);
1019 assert(destination);
1020 assert(port > 0);
1021 assert(p);
1022
1023 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1024
1025 sa = (union sockaddr_union) {
1026 .in.sin_family = AF_INET,
1027 .in.sin_addr = *destination,
1028 .in.sin_port = htobe16(port),
1029 };
1030
1031 if (ifindex > 0) {
1032 struct cmsghdr *cmsg;
1033 struct in_pktinfo *pi;
1034
1035 mh.msg_control = &control;
1036 mh.msg_controllen = sizeof(control);
1037
1038 cmsg = CMSG_FIRSTHDR(&mh);
1039 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
1040 cmsg->cmsg_level = IPPROTO_IP;
1041 cmsg->cmsg_type = IP_PKTINFO;
1042
1043 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
1044 pi->ipi_ifindex = ifindex;
1045
1046 if (source)
1047 pi->ipi_spec_dst = *source;
1048 }
1049
1050 return sendmsg_loop(fd, &mh, 0);
1051}
1052
1053static int manager_ipv6_send(
1054 Manager *m,
1055 int fd,
1056 int ifindex,
1057 const struct in6_addr *destination,
1058 uint16_t port,
1059 const struct in6_addr *source,
1060 DnsPacket *p) {
1061
1062 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1063 union sockaddr_union sa;
1064 struct iovec iov;
1065 struct msghdr mh = {
1066 .msg_iov = &iov,
1067 .msg_iovlen = 1,
1068 .msg_name = &sa.sa,
1069 .msg_namelen = sizeof(sa.in6),
1070 };
1071
1072 assert(m);
1073 assert(fd >= 0);
1074 assert(destination);
1075 assert(port > 0);
1076 assert(p);
1077
1078 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1079
1080 sa = (union sockaddr_union) {
1081 .in6.sin6_family = AF_INET6,
1082 .in6.sin6_addr = *destination,
1083 .in6.sin6_port = htobe16(port),
1084 .in6.sin6_scope_id = ifindex,
1085 };
1086
1087 if (ifindex > 0) {
1088 struct cmsghdr *cmsg;
1089 struct in6_pktinfo *pi;
1090
1091 mh.msg_control = &control;
1092 mh.msg_controllen = sizeof(control);
1093
1094 cmsg = CMSG_FIRSTHDR(&mh);
1095 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1096 cmsg->cmsg_level = IPPROTO_IPV6;
1097 cmsg->cmsg_type = IPV6_PKTINFO;
1098
1099 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1100 pi->ipi6_ifindex = ifindex;
1101
1102 if (source)
1103 pi->ipi6_addr = *source;
1104 }
1105
1106 return sendmsg_loop(fd, &mh, 0);
1107}
1108
1109int manager_send(
1110 Manager *m,
1111 int fd,
1112 int ifindex,
1113 int family,
1114 const union in_addr_union *destination,
1115 uint16_t port,
1116 const union in_addr_union *source,
1117 DnsPacket *p) {
1118
1119 assert(m);
1120 assert(fd >= 0);
1121 assert(destination);
1122 assert(port > 0);
1123 assert(p);
1124
1125 log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1126 DNS_PACKET_TC(p) ? "truncated (!) " : "",
1127 DNS_PACKET_QR(p) ? "response" : "query",
1128 DNS_PACKET_ID(p),
1129 ifindex, af_to_name(family),
1130 p->size);
1131
1132 if (family == AF_INET)
1133 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1134 if (family == AF_INET6)
1135 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1136
1137 return -EAFNOSUPPORT;
1138}
1139
1140uint32_t manager_find_mtu(Manager *m) {
1141 uint32_t mtu = 0;
1142 Link *l;
1143
1144 /* If we don't know on which link a DNS packet would be
1145 * delivered, let's find the largest MTU that works on all
1146 * interfaces we know of */
1147
1148 HASHMAP_FOREACH(l, m->links) {
1149 if (l->mtu <= 0)
1150 continue;
1151
1152 if (mtu <= 0 || l->mtu < mtu)
1153 mtu = l->mtu;
1154 }
1155
1156 return mtu;
1157}
1158
1159int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1160 LinkAddress *a;
1161
1162 assert(m);
1163
1164 if (!IN_SET(family, AF_INET, AF_INET6))
1165 return 0;
1166
1167 if (!in_addr)
1168 return 0;
1169
1170 a = manager_find_link_address(m, family, in_addr);
1171 if (a)
1172 return a->link->ifindex;
1173
1174 return 0;
1175}
1176
1177void manager_refresh_rrs(Manager *m) {
1178 Link *l;
1179 DnssdService *s;
1180
1181 assert(m);
1182
1183 m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1184 m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1185 m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1186 m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1187
1188 if (m->mdns_support == RESOLVE_SUPPORT_YES)
1189 HASHMAP_FOREACH(s, m->dnssd_services)
1190 if (dnssd_update_rrs(s) < 0)
1191 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1192
1193 HASHMAP_FOREACH(l, m->links) {
1194 link_add_rrs(l, true);
1195 link_add_rrs(l, false);
1196 }
1197}
1198
1199static int manager_next_random_name(const char *old, char **ret_new) {
1200 const char *p;
1201 uint64_t u, a;
1202 char *n;
1203
1204 p = strchr(old, 0);
1205 assert(p);
1206
1207 while (p > old) {
1208 if (!strchr(DIGITS, p[-1]))
1209 break;
1210
1211 p--;
1212 }
1213
1214 if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1215 u = 1;
1216
1217 /* Add a random number to the old value. This way we can avoid
1218 * that two hosts pick the same hostname, win on IPv4 and lose
1219 * on IPv6 (or vice versa), and pick the same hostname
1220 * replacement hostname, ad infinitum. We still want the
1221 * numbers to go up monotonically, hence we just add a random
1222 * value 1..10 */
1223
1224 random_bytes(&a, sizeof(a));
1225 u += 1 + a % 10;
1226
1227 if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1228 return -ENOMEM;
1229
1230 *ret_new = n;
1231
1232 return 0;
1233}
1234
1235int manager_next_hostname(Manager *m) {
1236 _cleanup_free_ char *h = NULL, *k = NULL;
1237 int r;
1238
1239 assert(m);
1240
1241 r = manager_next_random_name(m->llmnr_hostname, &h);
1242 if (r < 0)
1243 return r;
1244
1245 r = dns_name_concat(h, "local", 0, &k);
1246 if (r < 0)
1247 return r;
1248
1249 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1250
1251 free_and_replace(m->llmnr_hostname, h);
1252 free_and_replace(m->mdns_hostname, k);
1253
1254 manager_refresh_rrs(m);
1255 (void) manager_send_changed(m, "LLMNRHostname");
1256
1257 return 0;
1258}
1259
1260LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1261 Link *l;
1262
1263 assert(m);
1264
1265 if (!IN_SET(family, AF_INET, AF_INET6))
1266 return NULL;
1267
1268 if (!in_addr)
1269 return NULL;
1270
1271 HASHMAP_FOREACH(l, m->links) {
1272 LinkAddress *a;
1273
1274 a = link_find_address(l, family, in_addr);
1275 if (a)
1276 return a;
1277 }
1278
1279 return NULL;
1280}
1281
1282bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1283 assert(m);
1284 assert(p);
1285
1286 /* Let's see if this packet comes from an IP address we have on any local interface */
1287
1288 return !!manager_find_link_address(m, p->family, &p->sender);
1289}
1290
1291bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1292 DnsTransaction *t;
1293
1294 assert(m);
1295 assert(p);
1296
1297 /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1298 * one we just got. If so, it's almost definitely a packet loop of some kind. */
1299
1300 t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1301 if (!t)
1302 return false;
1303
1304 return t->sent && dns_packet_equal(t->sent, p);
1305}
1306
1307DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1308 Link *l;
1309
1310 assert(m);
1311 assert(p);
1312
1313 l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1314 if (!l)
1315 return NULL;
1316
1317 switch (p->protocol) {
1318 case DNS_PROTOCOL_LLMNR:
1319 if (p->family == AF_INET)
1320 return l->llmnr_ipv4_scope;
1321 else if (p->family == AF_INET6)
1322 return l->llmnr_ipv6_scope;
1323
1324 break;
1325
1326 case DNS_PROTOCOL_MDNS:
1327 if (p->family == AF_INET)
1328 return l->mdns_ipv4_scope;
1329 else if (p->family == AF_INET6)
1330 return l->mdns_ipv6_scope;
1331
1332 break;
1333
1334 default:
1335 break;
1336 }
1337
1338 return NULL;
1339}
1340
1341void manager_verify_all(Manager *m) {
1342 DnsScope *s;
1343
1344 assert(m);
1345
1346 LIST_FOREACH(scopes, s, m->dns_scopes)
1347 dns_zone_verify_all(&s->zone);
1348}
1349
1350int manager_is_own_hostname(Manager *m, const char *name) {
1351 int r;
1352
1353 assert(m);
1354 assert(name);
1355
1356 if (m->llmnr_hostname) {
1357 r = dns_name_equal(name, m->llmnr_hostname);
1358 if (r != 0)
1359 return r;
1360 }
1361
1362 if (m->mdns_hostname) {
1363 r = dns_name_equal(name, m->mdns_hostname);
1364 if (r != 0)
1365 return r;
1366 }
1367
1368 if (m->full_hostname)
1369 return dns_name_equal(name, m->full_hostname);
1370
1371 return 0;
1372}
1373
1374int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1375 DnsServer *s;
1376 Link *l;
1377 int r;
1378
1379 assert(m);
1380 assert(dns);
1381
1382 r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1383 if (r < 0)
1384 return r;
1385
1386 /* First add the system-wide servers and domains */
1387 LIST_FOREACH(servers, s, m->dns_servers) {
1388 r = ordered_set_put(*dns, s);
1389 if (r == -EEXIST)
1390 continue;
1391 if (r < 0)
1392 return r;
1393 }
1394
1395 /* Then, add the per-link servers */
1396 HASHMAP_FOREACH(l, m->links) {
1397 LIST_FOREACH(servers, s, l->dns_servers) {
1398 r = ordered_set_put(*dns, s);
1399 if (r == -EEXIST)
1400 continue;
1401 if (r < 0)
1402 return r;
1403 }
1404 }
1405
1406 /* If we found nothing, add the fallback servers */
1407 if (ordered_set_isempty(*dns)) {
1408 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1409 r = ordered_set_put(*dns, s);
1410 if (r == -EEXIST)
1411 continue;
1412 if (r < 0)
1413 return r;
1414 }
1415 }
1416
1417 return 0;
1418}
1419
1420/* filter_route is a tri-state:
1421 * < 0: no filtering
1422 * = 0 or false: return only domains which should be used for searching
1423 * > 0 or true: return only domains which are for routing only
1424 */
1425int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1426 DnsSearchDomain *d;
1427 Link *l;
1428 int r;
1429
1430 assert(m);
1431 assert(domains);
1432
1433 r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1434 if (r < 0)
1435 return r;
1436
1437 LIST_FOREACH(domains, d, m->search_domains) {
1438
1439 if (filter_route >= 0 &&
1440 d->route_only != !!filter_route)
1441 continue;
1442
1443 r = ordered_set_put(*domains, d->name);
1444 if (r == -EEXIST)
1445 continue;
1446 if (r < 0)
1447 return r;
1448 }
1449
1450 HASHMAP_FOREACH(l, m->links) {
1451
1452 LIST_FOREACH(domains, d, l->search_domains) {
1453
1454 if (filter_route >= 0 &&
1455 d->route_only != !!filter_route)
1456 continue;
1457
1458 r = ordered_set_put(*domains, d->name);
1459 if (r == -EEXIST)
1460 continue;
1461 if (r < 0)
1462 return r;
1463 }
1464 }
1465
1466 return 0;
1467}
1468
1469DnssecMode manager_get_dnssec_mode(Manager *m) {
1470 assert(m);
1471
1472 if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1473 return m->dnssec_mode;
1474
1475 return DNSSEC_NO;
1476}
1477
1478bool manager_dnssec_supported(Manager *m) {
1479 DnsServer *server;
1480 Link *l;
1481
1482 assert(m);
1483
1484 if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1485 return false;
1486
1487 server = manager_get_dns_server(m);
1488 if (server && !dns_server_dnssec_supported(server))
1489 return false;
1490
1491 HASHMAP_FOREACH(l, m->links)
1492 if (!link_dnssec_supported(l))
1493 return false;
1494
1495 return true;
1496}
1497
1498DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1499 assert(m);
1500
1501 if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1502 return m->dns_over_tls_mode;
1503
1504 return DNS_OVER_TLS_NO;
1505}
1506
1507void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1508
1509 assert(verdict >= 0);
1510 assert(verdict < _DNSSEC_VERDICT_MAX);
1511
1512 if (DEBUG_LOGGING) {
1513 char s[DNS_RESOURCE_KEY_STRING_MAX];
1514
1515 log_debug("Found verdict for lookup %s: %s",
1516 dns_resource_key_to_string(key, s, sizeof s),
1517 dnssec_verdict_to_string(verdict));
1518 }
1519
1520 m->n_dnssec_verdict[verdict]++;
1521}
1522
1523bool manager_routable(Manager *m) {
1524 Link *l;
1525
1526 assert(m);
1527
1528 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1529
1530 HASHMAP_FOREACH(l, m->links)
1531 if (link_relevant(l, AF_UNSPEC, false))
1532 return true;
1533
1534 return false;
1535}
1536
1537void manager_flush_caches(Manager *m, int log_level) {
1538 DnsScope *scope;
1539
1540 assert(m);
1541
1542 LIST_FOREACH(scopes, scope, m->dns_scopes)
1543 dns_cache_flush(&scope->cache);
1544
1545 log_full(log_level, "Flushed all caches.");
1546}
1547
1548void manager_reset_server_features(Manager *m) {
1549 Link *l;
1550
1551 dns_server_reset_features_all(m->dns_servers);
1552 dns_server_reset_features_all(m->fallback_dns_servers);
1553
1554 HASHMAP_FOREACH(l, m->links)
1555 dns_server_reset_features_all(l->dns_servers);
1556
1557 log_info("Resetting learnt feature levels on all servers.");
1558}
1559
1560void manager_cleanup_saved_user(Manager *m) {
1561 _cleanup_closedir_ DIR *d = NULL;
1562 struct dirent *de;
1563
1564 assert(m);
1565
1566 /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1567 * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1568 * be restarted without losing this data. */
1569
1570 d = opendir("/run/systemd/resolve/netif/");
1571 if (!d) {
1572 if (errno == ENOENT)
1573 return;
1574
1575 log_warning_errno(errno, "Failed to open interface directory: %m");
1576 return;
1577 }
1578
1579 FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1580 _cleanup_free_ char *p = NULL;
1581 int ifindex;
1582 Link *l;
1583
1584 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1585 continue;
1586
1587 if (dot_or_dot_dot(de->d_name))
1588 continue;
1589
1590 ifindex = parse_ifindex(de->d_name);
1591 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1592 goto rm;
1593
1594 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1595 if (!l) /* link vanished */
1596 goto rm;
1597
1598 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1599 goto rm;
1600
1601 continue;
1602
1603 rm:
1604 p = path_join("/run/systemd/resolve/netif", de->d_name);
1605 if (!p) {
1606 log_oom();
1607 return;
1608 }
1609
1610 (void) unlink(p);
1611 }
1612}
1613
1614bool manager_next_dnssd_names(Manager *m) {
1615 DnssdService *s;
1616 bool tried = false;
1617 int r;
1618
1619 assert(m);
1620
1621 HASHMAP_FOREACH(s, m->dnssd_services) {
1622 _cleanup_free_ char * new_name = NULL;
1623
1624 if (!s->withdrawn)
1625 continue;
1626
1627 r = manager_next_random_name(s->name_template, &new_name);
1628 if (r < 0) {
1629 log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1630 continue;
1631 }
1632
1633 free_and_replace(s->name_template, new_name);
1634
1635 s->withdrawn = false;
1636
1637 tried = true;
1638 }
1639
1640 if (tried)
1641 manager_refresh_rrs(m);
1642
1643 return tried;
1644}
1645
1646bool manager_server_is_stub(Manager *m, DnsServer *s) {
1647 DnsStubListenerExtra *l;
1648
1649 assert(m);
1650 assert(s);
1651
1652 /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1653 * extra careful, and check here again */
1654 if (s->family == AF_INET &&
1655 s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1656 dns_server_port(s) == 53)
1657 return true;
1658
1659 /* Main reason to call this is to check server data against the extra listeners, and filter things
1660 * out. */
1661 ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1662 if (s->family == l->family &&
1663 in_addr_equal(s->family, &s->address, &l->address) &&
1664 dns_server_port(s) == dns_stub_listener_extra_port(l))
1665 return true;
1666
1667 return false;
1668}
1669
1670int socket_disable_pmtud(int fd, int af) {
1671 int r;
1672
1673 assert(fd >= 0);
1674
1675 if (af == AF_UNSPEC) {
1676 r = socket_get_family(fd, &af);
1677 if (r < 0)
1678 return r;
1679 }
1680
1681 switch (af) {
1682
1683 case AF_INET: {
1684 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1685 * PMTU forgery vulnerabilities.
1686 *
1687 * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1688 * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1689 * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1690 * discovery.
1691 *
1692 * This helps mitigating the PMTUD vulnerability described here:
1693 *
1694 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1695 *
1696 * Similar logic is in place in most DNS servers.
1697 *
1698 * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1699 * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1700 * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1701 * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1702 * fragments seen — and if we need larger packets always go to TCP.
1703 */
1704
1705 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1706 if (r < 0)
1707 return r;
1708
1709 return 0;
1710 }
1711
1712 case AF_INET6: {
1713 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1714 * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1715 * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1716 * because there's nothing that could be fragmented further anymore. */
1717
1718 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1719 if (r < 0)
1720 return r;
1721
1722 return 0;
1723 }
1724
1725 default:
1726 return -EAFNOSUPPORT;
1727 }
1728}
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