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core: fix stack-use-after-scope
[thirdparty/systemd.git] / src / resolve / resolved-manager.c
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3#include <fcntl.h>
4#include <netinet/in.h>
5#include <poll.h>
6#include <sys/ioctl.h>
7#include <sys/stat.h>
8#include <sys/types.h>
9#include <unistd.h>
10
11#include "af-list.h"
12#include "alloc-util.h"
13#include "bus-polkit.h"
14#include "dirent-util.h"
15#include "dns-domain.h"
16#include "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 char* fallback_hostname(void) {
446
447 /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
448 * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
449 * instead. */
450
451 _cleanup_free_ char *n = get_default_hostname();
452 if (!n)
453 return NULL;
454
455 if (is_localhost(n))
456 return strdup("linux");
457
458 return TAKE_PTR(n);
459}
460
461static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
462 _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
463 char label[DNS_LABEL_MAX];
464 const char *p;
465 int r;
466
467 assert(full_hostname);
468 assert(llmnr_hostname);
469 assert(mdns_hostname);
470
471 p = h = fallback_hostname();
472 if (!h)
473 return log_oom();
474
475 r = dns_label_unescape(&p, label, sizeof label, 0);
476 if (r < 0)
477 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
478
479 assert(r > 0); /* The fallback hostname must have at least one label */
480
481 r = dns_label_escape_new(label, r, &n);
482 if (r < 0)
483 return log_error_errno(r, "Failed to escape fallback hostname: %m");
484
485 r = dns_name_concat(n, "local", 0, &m);
486 if (r < 0)
487 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
488
489 *llmnr_hostname = TAKE_PTR(n);
490 *mdns_hostname = TAKE_PTR(m);
491 *full_hostname = TAKE_PTR(h);
492
493 return 0;
494}
495
496static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
497 _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
498 Manager *m = userdata;
499 bool llmnr_hostname_changed;
500 int r;
501
502 assert(m);
503
504 r = determine_hostname(&full_hostname, &llmnr_hostname, &mdns_hostname);
505 if (r < 0)
506 return 0; /* ignore invalid hostnames */
507
508 llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
509 if (streq(full_hostname, m->full_hostname) &&
510 !llmnr_hostname_changed &&
511 streq(mdns_hostname, m->mdns_hostname))
512 return 0;
513
514 log_info("System hostname changed to '%s'.", full_hostname);
515
516 free_and_replace(m->full_hostname, full_hostname);
517 free_and_replace(m->llmnr_hostname, llmnr_hostname);
518 free_and_replace(m->mdns_hostname, mdns_hostname);
519
520 manager_refresh_rrs(m);
521 (void) manager_send_changed(m, "LLMNRHostname");
522
523 return 0;
524}
525
526static int manager_watch_hostname(Manager *m) {
527 int r;
528
529 assert(m);
530
531 m->hostname_fd = open("/proc/sys/kernel/hostname",
532 O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
533 if (m->hostname_fd < 0) {
534 log_warning_errno(errno, "Failed to watch hostname: %m");
535 return 0;
536 }
537
538 r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
539 if (r < 0) {
540 if (r == -EPERM)
541 /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
542 m->hostname_fd = safe_close(m->hostname_fd);
543 else
544 return log_error_errno(r, "Failed to add hostname event source: %m");
545 }
546
547 (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
548
549 r = determine_hostname(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
550 if (r < 0) {
551 log_info("Defaulting to hostname '%s'.", fallback_hostname());
552
553 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
554 if (r < 0)
555 return r;
556 } else
557 log_info("Using system hostname '%s'.", m->full_hostname);
558
559 return 0;
560}
561
562static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
563 _cleanup_free_ char *buffer = NULL;
564 _cleanup_fclose_ FILE *f = NULL;
565 Manager *m = userdata;
566 DnsServer *server;
567 size_t size = 0;
568 DnsScope *scope;
569 Link *l;
570
571 assert(s);
572 assert(si);
573 assert(m);
574
575 f = open_memstream_unlocked(&buffer, &size);
576 if (!f)
577 return log_oom();
578
579 LIST_FOREACH(scopes, scope, m->dns_scopes)
580 dns_scope_dump(scope, f);
581
582 LIST_FOREACH(servers, server, m->dns_servers)
583 dns_server_dump(server, f);
584 LIST_FOREACH(servers, server, m->fallback_dns_servers)
585 dns_server_dump(server, f);
586 HASHMAP_FOREACH(l, m->links)
587 LIST_FOREACH(servers, server, l->dns_servers)
588 dns_server_dump(server, f);
589
590 if (fflush_and_check(f) < 0)
591 return log_oom();
592
593 log_dump(LOG_INFO, buffer);
594 return 0;
595}
596
597static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
598 Manager *m = userdata;
599
600 assert(s);
601 assert(si);
602 assert(m);
603
604 manager_flush_caches(m, LOG_INFO);
605
606 return 0;
607}
608
609static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
610 Manager *m = userdata;
611
612 assert(s);
613 assert(si);
614 assert(m);
615
616 manager_reset_server_features(m);
617 return 0;
618}
619
620int manager_new(Manager **ret) {
621 _cleanup_(manager_freep) Manager *m = NULL;
622 int r;
623
624 assert(ret);
625
626 m = new(Manager, 1);
627 if (!m)
628 return -ENOMEM;
629
630 *m = (Manager) {
631 .llmnr_ipv4_udp_fd = -1,
632 .llmnr_ipv6_udp_fd = -1,
633 .llmnr_ipv4_tcp_fd = -1,
634 .llmnr_ipv6_tcp_fd = -1,
635 .mdns_ipv4_fd = -1,
636 .mdns_ipv6_fd = -1,
637 .hostname_fd = -1,
638
639 .llmnr_support = DEFAULT_LLMNR_MODE,
640 .mdns_support = DEFAULT_MDNS_MODE,
641 .dnssec_mode = DEFAULT_DNSSEC_MODE,
642 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
643 .enable_cache = DNS_CACHE_MODE_YES,
644 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
645 .read_resolv_conf = true,
646 .need_builtin_fallbacks = true,
647 .etc_hosts_last = USEC_INFINITY,
648 .read_etc_hosts = true,
649 };
650
651 r = dns_trust_anchor_load(&m->trust_anchor);
652 if (r < 0)
653 return r;
654
655 r = manager_parse_config_file(m);
656 if (r < 0)
657 log_warning_errno(r, "Failed to parse configuration file: %m");
658
659#if ENABLE_DNS_OVER_TLS
660 r = dnstls_manager_init(m);
661 if (r < 0)
662 return r;
663#endif
664
665 r = sd_event_default(&m->event);
666 if (r < 0)
667 return r;
668
669 (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
670 (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
671
672 (void) sd_event_set_watchdog(m->event, true);
673
674 r = manager_watch_hostname(m);
675 if (r < 0)
676 return r;
677
678 r = dnssd_load(m);
679 if (r < 0)
680 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
681
682 r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
683 if (r < 0)
684 return r;
685
686 r = manager_network_monitor_listen(m);
687 if (r < 0)
688 return r;
689
690 r = manager_rtnl_listen(m);
691 if (r < 0)
692 return r;
693
694 r = manager_clock_change_listen(m);
695 if (r < 0)
696 return r;
697
698 r = manager_connect_bus(m);
699 if (r < 0)
700 return r;
701
702 (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
703 (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
704 (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
705
706 manager_cleanup_saved_user(m);
707
708 *ret = TAKE_PTR(m);
709
710 return 0;
711}
712
713int manager_start(Manager *m) {
714 int r;
715
716 assert(m);
717
718 r = manager_dns_stub_start(m);
719 if (r < 0)
720 return r;
721
722 r = manager_varlink_init(m);
723 if (r < 0)
724 return r;
725
726 return 0;
727}
728
729Manager *manager_free(Manager *m) {
730 Link *l;
731 DnssdService *s;
732
733 if (!m)
734 return NULL;
735
736 dns_server_unlink_all(m->dns_servers);
737 dns_server_unlink_all(m->fallback_dns_servers);
738 dns_search_domain_unlink_all(m->search_domains);
739
740 while ((l = hashmap_first(m->links)))
741 link_free(l);
742
743 while (m->dns_queries)
744 dns_query_free(m->dns_queries);
745
746 m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
747
748 dns_scope_free(m->unicast_scope);
749
750 /* At this point only orphaned streams should remain. All others should have been freed already by their
751 * owners */
752 while (m->dns_streams)
753 dns_stream_unref(m->dns_streams);
754
755#if ENABLE_DNS_OVER_TLS
756 dnstls_manager_free(m);
757#endif
758
759 hashmap_free(m->links);
760 hashmap_free(m->dns_transactions);
761
762 sd_event_source_unref(m->network_event_source);
763 sd_network_monitor_unref(m->network_monitor);
764
765 sd_netlink_unref(m->rtnl);
766 sd_event_source_unref(m->rtnl_event_source);
767 sd_event_source_unref(m->clock_change_event_source);
768
769 manager_llmnr_stop(m);
770 manager_mdns_stop(m);
771 manager_dns_stub_stop(m);
772 manager_varlink_done(m);
773
774 manager_socket_graveyard_clear(m);
775
776 ordered_set_free(m->dns_extra_stub_listeners);
777
778 bus_verify_polkit_async_registry_free(m->polkit_registry);
779
780 sd_bus_flush_close_unref(m->bus);
781
782 sd_event_source_unref(m->sigusr1_event_source);
783 sd_event_source_unref(m->sigusr2_event_source);
784 sd_event_source_unref(m->sigrtmin1_event_source);
785
786 sd_event_unref(m->event);
787
788 dns_resource_key_unref(m->llmnr_host_ipv4_key);
789 dns_resource_key_unref(m->llmnr_host_ipv6_key);
790 dns_resource_key_unref(m->mdns_host_ipv4_key);
791 dns_resource_key_unref(m->mdns_host_ipv6_key);
792
793 sd_event_source_unref(m->hostname_event_source);
794 safe_close(m->hostname_fd);
795
796 free(m->full_hostname);
797 free(m->llmnr_hostname);
798 free(m->mdns_hostname);
799
800 while ((s = hashmap_first(m->dnssd_services)))
801 dnssd_service_free(s);
802 hashmap_free(m->dnssd_services);
803
804 dns_trust_anchor_flush(&m->trust_anchor);
805 manager_etc_hosts_flush(m);
806
807 return mfree(m);
808}
809
810int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
811 _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
812 CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
813 + CMSG_SPACE(int) /* ttl/hoplimit */
814 + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
815 union sockaddr_union sa;
816 struct iovec iov;
817 struct msghdr mh = {
818 .msg_name = &sa.sa,
819 .msg_namelen = sizeof(sa),
820 .msg_iov = &iov,
821 .msg_iovlen = 1,
822 .msg_control = &control,
823 .msg_controllen = sizeof(control),
824 };
825 struct cmsghdr *cmsg;
826 ssize_t ms, l;
827 int r;
828
829 assert(m);
830 assert(fd >= 0);
831 assert(ret);
832
833 ms = next_datagram_size_fd(fd);
834 if (ms < 0)
835 return ms;
836
837 r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
838 if (r < 0)
839 return r;
840
841 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
842
843 l = recvmsg_safe(fd, &mh, 0);
844 if (IN_SET(l, -EAGAIN, -EINTR))
845 return 0;
846 if (l <= 0)
847 return l;
848
849 assert(!(mh.msg_flags & MSG_TRUNC));
850
851 p->size = (size_t) l;
852
853 p->family = sa.sa.sa_family;
854 p->ipproto = IPPROTO_UDP;
855 if (p->family == AF_INET) {
856 p->sender.in = sa.in.sin_addr;
857 p->sender_port = be16toh(sa.in.sin_port);
858 } else if (p->family == AF_INET6) {
859 p->sender.in6 = sa.in6.sin6_addr;
860 p->sender_port = be16toh(sa.in6.sin6_port);
861 p->ifindex = sa.in6.sin6_scope_id;
862 } else
863 return -EAFNOSUPPORT;
864
865 p->timestamp = now(clock_boottime_or_monotonic());
866
867 CMSG_FOREACH(cmsg, &mh) {
868
869 if (cmsg->cmsg_level == IPPROTO_IPV6) {
870 assert(p->family == AF_INET6);
871
872 switch (cmsg->cmsg_type) {
873
874 case IPV6_PKTINFO: {
875 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
876
877 if (p->ifindex <= 0)
878 p->ifindex = i->ipi6_ifindex;
879
880 p->destination.in6 = i->ipi6_addr;
881 break;
882 }
883
884 case IPV6_HOPLIMIT:
885 p->ttl = *(int *) CMSG_DATA(cmsg);
886 break;
887
888 case IPV6_RECVFRAGSIZE:
889 p->fragsize = *(int *) CMSG_DATA(cmsg);
890 break;
891 }
892 } else if (cmsg->cmsg_level == IPPROTO_IP) {
893 assert(p->family == AF_INET);
894
895 switch (cmsg->cmsg_type) {
896
897 case IP_PKTINFO: {
898 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
899
900 if (p->ifindex <= 0)
901 p->ifindex = i->ipi_ifindex;
902
903 p->destination.in = i->ipi_addr;
904 break;
905 }
906
907 case IP_TTL:
908 p->ttl = *(int *) CMSG_DATA(cmsg);
909 break;
910
911 case IP_RECVFRAGSIZE:
912 p->fragsize = *(int *) CMSG_DATA(cmsg);
913 break;
914 }
915 }
916 }
917
918 /* The Linux kernel sets the interface index to the loopback
919 * device if the packet came from the local host since it
920 * avoids the routing table in such a case. Let's unset the
921 * interface index in such a case. */
922 if (p->ifindex == LOOPBACK_IFINDEX)
923 p->ifindex = 0;
924
925 if (protocol != DNS_PROTOCOL_DNS) {
926 /* If we don't know the interface index still, we look for the
927 * first local interface with a matching address. Yuck! */
928 if (p->ifindex <= 0)
929 p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
930 }
931
932 log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%i, fragsize=%zu",
933 dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize);
934
935 *ret = TAKE_PTR(p);
936 return 1;
937}
938
939static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
940 int r;
941
942 assert(fd >= 0);
943 assert(mh);
944
945 for (;;) {
946 if (sendmsg(fd, mh, flags) >= 0)
947 return 0;
948
949 if (errno == EINTR)
950 continue;
951
952 if (errno != EAGAIN)
953 return -errno;
954
955 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
956 if (r < 0)
957 return r;
958 if (r == 0)
959 return -ETIMEDOUT;
960 }
961}
962
963static int write_loop(int fd, void *message, size_t length) {
964 int r;
965
966 assert(fd >= 0);
967 assert(message);
968
969 for (;;) {
970 if (write(fd, message, length) >= 0)
971 return 0;
972
973 if (errno == EINTR)
974 continue;
975
976 if (errno != EAGAIN)
977 return -errno;
978
979 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
980 if (r < 0)
981 return r;
982 if (r == 0)
983 return -ETIMEDOUT;
984 }
985}
986
987int manager_write(Manager *m, int fd, DnsPacket *p) {
988 int r;
989
990 log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
991 DNS_PACKET_TC(p) ? "truncated (!) " : "",
992 DNS_PACKET_QR(p) ? "response" : "query",
993 DNS_PACKET_ID(p),
994 p->size);
995
996 r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
997 if (r < 0)
998 return r;
999
1000 return 0;
1001}
1002
1003static int manager_ipv4_send(
1004 Manager *m,
1005 int fd,
1006 int ifindex,
1007 const struct in_addr *destination,
1008 uint16_t port,
1009 const struct in_addr *source,
1010 DnsPacket *p) {
1011
1012 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
1013 union sockaddr_union sa;
1014 struct iovec iov;
1015 struct msghdr mh = {
1016 .msg_iov = &iov,
1017 .msg_iovlen = 1,
1018 .msg_name = &sa.sa,
1019 .msg_namelen = sizeof(sa.in),
1020 };
1021
1022 assert(m);
1023 assert(fd >= 0);
1024 assert(destination);
1025 assert(port > 0);
1026 assert(p);
1027
1028 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1029
1030 sa = (union sockaddr_union) {
1031 .in.sin_family = AF_INET,
1032 .in.sin_addr = *destination,
1033 .in.sin_port = htobe16(port),
1034 };
1035
1036 if (ifindex > 0) {
1037 struct cmsghdr *cmsg;
1038 struct in_pktinfo *pi;
1039
1040 mh.msg_control = &control;
1041 mh.msg_controllen = sizeof(control);
1042
1043 cmsg = CMSG_FIRSTHDR(&mh);
1044 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
1045 cmsg->cmsg_level = IPPROTO_IP;
1046 cmsg->cmsg_type = IP_PKTINFO;
1047
1048 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
1049 pi->ipi_ifindex = ifindex;
1050
1051 if (source)
1052 pi->ipi_spec_dst = *source;
1053 }
1054
1055 return sendmsg_loop(fd, &mh, 0);
1056}
1057
1058static int manager_ipv6_send(
1059 Manager *m,
1060 int fd,
1061 int ifindex,
1062 const struct in6_addr *destination,
1063 uint16_t port,
1064 const struct in6_addr *source,
1065 DnsPacket *p) {
1066
1067 CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1068 union sockaddr_union sa;
1069 struct iovec iov;
1070 struct msghdr mh = {
1071 .msg_iov = &iov,
1072 .msg_iovlen = 1,
1073 .msg_name = &sa.sa,
1074 .msg_namelen = sizeof(sa.in6),
1075 };
1076
1077 assert(m);
1078 assert(fd >= 0);
1079 assert(destination);
1080 assert(port > 0);
1081 assert(p);
1082
1083 iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1084
1085 sa = (union sockaddr_union) {
1086 .in6.sin6_family = AF_INET6,
1087 .in6.sin6_addr = *destination,
1088 .in6.sin6_port = htobe16(port),
1089 .in6.sin6_scope_id = ifindex,
1090 };
1091
1092 if (ifindex > 0) {
1093 struct cmsghdr *cmsg;
1094 struct in6_pktinfo *pi;
1095
1096 mh.msg_control = &control;
1097 mh.msg_controllen = sizeof(control);
1098
1099 cmsg = CMSG_FIRSTHDR(&mh);
1100 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1101 cmsg->cmsg_level = IPPROTO_IPV6;
1102 cmsg->cmsg_type = IPV6_PKTINFO;
1103
1104 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1105 pi->ipi6_ifindex = ifindex;
1106
1107 if (source)
1108 pi->ipi6_addr = *source;
1109 }
1110
1111 return sendmsg_loop(fd, &mh, 0);
1112}
1113
1114int manager_send(
1115 Manager *m,
1116 int fd,
1117 int ifindex,
1118 int family,
1119 const union in_addr_union *destination,
1120 uint16_t port,
1121 const union in_addr_union *source,
1122 DnsPacket *p) {
1123
1124 assert(m);
1125 assert(fd >= 0);
1126 assert(destination);
1127 assert(port > 0);
1128 assert(p);
1129
1130 log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1131 DNS_PACKET_TC(p) ? "truncated (!) " : "",
1132 DNS_PACKET_QR(p) ? "response" : "query",
1133 DNS_PACKET_ID(p),
1134 ifindex, af_to_name(family),
1135 p->size);
1136
1137 if (family == AF_INET)
1138 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1139 if (family == AF_INET6)
1140 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1141
1142 return -EAFNOSUPPORT;
1143}
1144
1145uint32_t manager_find_mtu(Manager *m) {
1146 uint32_t mtu = 0;
1147 Link *l;
1148
1149 /* If we don't know on which link a DNS packet would be
1150 * delivered, let's find the largest MTU that works on all
1151 * interfaces we know of */
1152
1153 HASHMAP_FOREACH(l, m->links) {
1154 if (l->mtu <= 0)
1155 continue;
1156
1157 if (mtu <= 0 || l->mtu < mtu)
1158 mtu = l->mtu;
1159 }
1160
1161 return mtu;
1162}
1163
1164int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1165 LinkAddress *a;
1166
1167 assert(m);
1168
1169 if (!IN_SET(family, AF_INET, AF_INET6))
1170 return 0;
1171
1172 if (!in_addr)
1173 return 0;
1174
1175 a = manager_find_link_address(m, family, in_addr);
1176 if (a)
1177 return a->link->ifindex;
1178
1179 return 0;
1180}
1181
1182void manager_refresh_rrs(Manager *m) {
1183 Link *l;
1184 DnssdService *s;
1185
1186 assert(m);
1187
1188 m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1189 m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1190 m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1191 m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1192
1193 if (m->mdns_support == RESOLVE_SUPPORT_YES)
1194 HASHMAP_FOREACH(s, m->dnssd_services)
1195 if (dnssd_update_rrs(s) < 0)
1196 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1197
1198 HASHMAP_FOREACH(l, m->links) {
1199 link_add_rrs(l, true);
1200 link_add_rrs(l, false);
1201 }
1202}
1203
1204static int manager_next_random_name(const char *old, char **ret_new) {
1205 const char *p;
1206 uint64_t u, a;
1207 char *n;
1208
1209 p = strchr(old, 0);
1210 assert(p);
1211
1212 while (p > old) {
1213 if (!strchr(DIGITS, p[-1]))
1214 break;
1215
1216 p--;
1217 }
1218
1219 if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1220 u = 1;
1221
1222 /* Add a random number to the old value. This way we can avoid
1223 * that two hosts pick the same hostname, win on IPv4 and lose
1224 * on IPv6 (or vice versa), and pick the same hostname
1225 * replacement hostname, ad infinitum. We still want the
1226 * numbers to go up monotonically, hence we just add a random
1227 * value 1..10 */
1228
1229 random_bytes(&a, sizeof(a));
1230 u += 1 + a % 10;
1231
1232 if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1233 return -ENOMEM;
1234
1235 *ret_new = n;
1236
1237 return 0;
1238}
1239
1240int manager_next_hostname(Manager *m) {
1241 _cleanup_free_ char *h = NULL, *k = NULL;
1242 int r;
1243
1244 assert(m);
1245
1246 r = manager_next_random_name(m->llmnr_hostname, &h);
1247 if (r < 0)
1248 return r;
1249
1250 r = dns_name_concat(h, "local", 0, &k);
1251 if (r < 0)
1252 return r;
1253
1254 log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1255
1256 free_and_replace(m->llmnr_hostname, h);
1257 free_and_replace(m->mdns_hostname, k);
1258
1259 manager_refresh_rrs(m);
1260 (void) manager_send_changed(m, "LLMNRHostname");
1261
1262 return 0;
1263}
1264
1265LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1266 Link *l;
1267
1268 assert(m);
1269
1270 if (!IN_SET(family, AF_INET, AF_INET6))
1271 return NULL;
1272
1273 if (!in_addr)
1274 return NULL;
1275
1276 HASHMAP_FOREACH(l, m->links) {
1277 LinkAddress *a;
1278
1279 a = link_find_address(l, family, in_addr);
1280 if (a)
1281 return a;
1282 }
1283
1284 return NULL;
1285}
1286
1287bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1288 assert(m);
1289 assert(p);
1290
1291 /* Let's see if this packet comes from an IP address we have on any local interface */
1292
1293 return !!manager_find_link_address(m, p->family, &p->sender);
1294}
1295
1296bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1297 DnsTransaction *t;
1298
1299 assert(m);
1300 assert(p);
1301
1302 /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1303 * one we just got. If so, it's almost definitely a packet loop of some kind. */
1304
1305 t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1306 if (!t)
1307 return false;
1308
1309 return t->sent && dns_packet_equal(t->sent, p);
1310}
1311
1312DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1313 Link *l;
1314
1315 assert(m);
1316 assert(p);
1317
1318 l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1319 if (!l)
1320 return NULL;
1321
1322 switch (p->protocol) {
1323 case DNS_PROTOCOL_LLMNR:
1324 if (p->family == AF_INET)
1325 return l->llmnr_ipv4_scope;
1326 else if (p->family == AF_INET6)
1327 return l->llmnr_ipv6_scope;
1328
1329 break;
1330
1331 case DNS_PROTOCOL_MDNS:
1332 if (p->family == AF_INET)
1333 return l->mdns_ipv4_scope;
1334 else if (p->family == AF_INET6)
1335 return l->mdns_ipv6_scope;
1336
1337 break;
1338
1339 default:
1340 break;
1341 }
1342
1343 return NULL;
1344}
1345
1346void manager_verify_all(Manager *m) {
1347 DnsScope *s;
1348
1349 assert(m);
1350
1351 LIST_FOREACH(scopes, s, m->dns_scopes)
1352 dns_zone_verify_all(&s->zone);
1353}
1354
1355int manager_is_own_hostname(Manager *m, const char *name) {
1356 int r;
1357
1358 assert(m);
1359 assert(name);
1360
1361 if (m->llmnr_hostname) {
1362 r = dns_name_equal(name, m->llmnr_hostname);
1363 if (r != 0)
1364 return r;
1365 }
1366
1367 if (m->mdns_hostname) {
1368 r = dns_name_equal(name, m->mdns_hostname);
1369 if (r != 0)
1370 return r;
1371 }
1372
1373 if (m->full_hostname)
1374 return dns_name_equal(name, m->full_hostname);
1375
1376 return 0;
1377}
1378
1379int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1380 DnsServer *s;
1381 Link *l;
1382 int r;
1383
1384 assert(m);
1385 assert(dns);
1386
1387 r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1388 if (r < 0)
1389 return r;
1390
1391 /* First add the system-wide servers and domains */
1392 LIST_FOREACH(servers, s, m->dns_servers) {
1393 r = ordered_set_put(*dns, s);
1394 if (r == -EEXIST)
1395 continue;
1396 if (r < 0)
1397 return r;
1398 }
1399
1400 /* Then, add the per-link servers */
1401 HASHMAP_FOREACH(l, m->links) {
1402 LIST_FOREACH(servers, s, l->dns_servers) {
1403 r = ordered_set_put(*dns, s);
1404 if (r == -EEXIST)
1405 continue;
1406 if (r < 0)
1407 return r;
1408 }
1409 }
1410
1411 /* If we found nothing, add the fallback servers */
1412 if (ordered_set_isempty(*dns)) {
1413 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1414 r = ordered_set_put(*dns, s);
1415 if (r == -EEXIST)
1416 continue;
1417 if (r < 0)
1418 return r;
1419 }
1420 }
1421
1422 return 0;
1423}
1424
1425/* filter_route is a tri-state:
1426 * < 0: no filtering
1427 * = 0 or false: return only domains which should be used for searching
1428 * > 0 or true: return only domains which are for routing only
1429 */
1430int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1431 DnsSearchDomain *d;
1432 Link *l;
1433 int r;
1434
1435 assert(m);
1436 assert(domains);
1437
1438 r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1439 if (r < 0)
1440 return r;
1441
1442 LIST_FOREACH(domains, d, m->search_domains) {
1443
1444 if (filter_route >= 0 &&
1445 d->route_only != !!filter_route)
1446 continue;
1447
1448 r = ordered_set_put(*domains, d->name);
1449 if (r == -EEXIST)
1450 continue;
1451 if (r < 0)
1452 return r;
1453 }
1454
1455 HASHMAP_FOREACH(l, m->links) {
1456
1457 LIST_FOREACH(domains, d, l->search_domains) {
1458
1459 if (filter_route >= 0 &&
1460 d->route_only != !!filter_route)
1461 continue;
1462
1463 r = ordered_set_put(*domains, d->name);
1464 if (r == -EEXIST)
1465 continue;
1466 if (r < 0)
1467 return r;
1468 }
1469 }
1470
1471 return 0;
1472}
1473
1474DnssecMode manager_get_dnssec_mode(Manager *m) {
1475 assert(m);
1476
1477 if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1478 return m->dnssec_mode;
1479
1480 return DNSSEC_NO;
1481}
1482
1483bool manager_dnssec_supported(Manager *m) {
1484 DnsServer *server;
1485 Link *l;
1486
1487 assert(m);
1488
1489 if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1490 return false;
1491
1492 server = manager_get_dns_server(m);
1493 if (server && !dns_server_dnssec_supported(server))
1494 return false;
1495
1496 HASHMAP_FOREACH(l, m->links)
1497 if (!link_dnssec_supported(l))
1498 return false;
1499
1500 return true;
1501}
1502
1503DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1504 assert(m);
1505
1506 if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1507 return m->dns_over_tls_mode;
1508
1509 return DNS_OVER_TLS_NO;
1510}
1511
1512void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1513
1514 assert(verdict >= 0);
1515 assert(verdict < _DNSSEC_VERDICT_MAX);
1516
1517 if (DEBUG_LOGGING) {
1518 char s[DNS_RESOURCE_KEY_STRING_MAX];
1519
1520 log_debug("Found verdict for lookup %s: %s",
1521 dns_resource_key_to_string(key, s, sizeof s),
1522 dnssec_verdict_to_string(verdict));
1523 }
1524
1525 m->n_dnssec_verdict[verdict]++;
1526}
1527
1528bool manager_routable(Manager *m) {
1529 Link *l;
1530
1531 assert(m);
1532
1533 /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1534
1535 HASHMAP_FOREACH(l, m->links)
1536 if (link_relevant(l, AF_UNSPEC, false))
1537 return true;
1538
1539 return false;
1540}
1541
1542void manager_flush_caches(Manager *m, int log_level) {
1543 DnsScope *scope;
1544
1545 assert(m);
1546
1547 LIST_FOREACH(scopes, scope, m->dns_scopes)
1548 dns_cache_flush(&scope->cache);
1549
1550 log_full(log_level, "Flushed all caches.");
1551}
1552
1553void manager_reset_server_features(Manager *m) {
1554 Link *l;
1555
1556 dns_server_reset_features_all(m->dns_servers);
1557 dns_server_reset_features_all(m->fallback_dns_servers);
1558
1559 HASHMAP_FOREACH(l, m->links)
1560 dns_server_reset_features_all(l->dns_servers);
1561
1562 log_info("Resetting learnt feature levels on all servers.");
1563}
1564
1565void manager_cleanup_saved_user(Manager *m) {
1566 _cleanup_closedir_ DIR *d = NULL;
1567 struct dirent *de;
1568
1569 assert(m);
1570
1571 /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1572 * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1573 * be restarted without losing this data. */
1574
1575 d = opendir("/run/systemd/resolve/netif/");
1576 if (!d) {
1577 if (errno == ENOENT)
1578 return;
1579
1580 log_warning_errno(errno, "Failed to open interface directory: %m");
1581 return;
1582 }
1583
1584 FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1585 _cleanup_free_ char *p = NULL;
1586 int ifindex;
1587 Link *l;
1588
1589 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1590 continue;
1591
1592 if (dot_or_dot_dot(de->d_name))
1593 continue;
1594
1595 ifindex = parse_ifindex(de->d_name);
1596 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1597 goto rm;
1598
1599 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1600 if (!l) /* link vanished */
1601 goto rm;
1602
1603 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1604 goto rm;
1605
1606 continue;
1607
1608 rm:
1609 p = path_join("/run/systemd/resolve/netif", de->d_name);
1610 if (!p) {
1611 log_oom();
1612 return;
1613 }
1614
1615 (void) unlink(p);
1616 }
1617}
1618
1619bool manager_next_dnssd_names(Manager *m) {
1620 DnssdService *s;
1621 bool tried = false;
1622 int r;
1623
1624 assert(m);
1625
1626 HASHMAP_FOREACH(s, m->dnssd_services) {
1627 _cleanup_free_ char * new_name = NULL;
1628
1629 if (!s->withdrawn)
1630 continue;
1631
1632 r = manager_next_random_name(s->name_template, &new_name);
1633 if (r < 0) {
1634 log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1635 continue;
1636 }
1637
1638 free_and_replace(s->name_template, new_name);
1639
1640 s->withdrawn = false;
1641
1642 tried = true;
1643 }
1644
1645 if (tried)
1646 manager_refresh_rrs(m);
1647
1648 return tried;
1649}
1650
1651bool manager_server_is_stub(Manager *m, DnsServer *s) {
1652 DnsStubListenerExtra *l;
1653
1654 assert(m);
1655 assert(s);
1656
1657 /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1658 * extra careful, and check here again */
1659 if (s->family == AF_INET &&
1660 s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1661 dns_server_port(s) == 53)
1662 return true;
1663
1664 /* Main reason to call this is to check server data against the extra listeners, and filter things
1665 * out. */
1666 ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1667 if (s->family == l->family &&
1668 in_addr_equal(s->family, &s->address, &l->address) &&
1669 dns_server_port(s) == dns_stub_listener_extra_port(l))
1670 return true;
1671
1672 return false;
1673}
1674
1675int socket_disable_pmtud(int fd, int af) {
1676 int r;
1677
1678 assert(fd >= 0);
1679
1680 if (af == AF_UNSPEC) {
1681 r = socket_get_family(fd, &af);
1682 if (r < 0)
1683 return r;
1684 }
1685
1686 switch (af) {
1687
1688 case AF_INET: {
1689 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1690 * PMTU forgery vulnerabilities.
1691 *
1692 * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1693 * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1694 * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1695 * discovery.
1696 *
1697 * This helps mitigating the PMTUD vulnerability described here:
1698 *
1699 * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1700 *
1701 * Similar logic is in place in most DNS servers.
1702 *
1703 * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1704 * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1705 * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1706 * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1707 * fragments seen — and if we need larger packets always go to TCP.
1708 */
1709
1710 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1711 if (r < 0)
1712 return r;
1713
1714 return 0;
1715 }
1716
1717 case AF_INET6: {
1718 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1719 * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1720 * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1721 * because there's nothing that could be fragmented further anymore. */
1722
1723 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1724 if (r < 0)
1725 return r;
1726
1727 return 0;
1728 }
1729
1730 default:
1731 return -EAFNOSUPPORT;
1732 }
1733}
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