src/resolve/resolved-manager.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <fcntl.h>
   4 #include <netinet/in.h>
   5 #include <poll.h>
   6 #include <sys/ioctl.h>
   7 #include <sys/stat.h>
   8 #include <sys/types.h>
   9 #include <unistd.h>
  10
  11 #include "af-list.h"
  12 #include "alloc-util.h"
  13 #include "bus-polkit.h"
  14 #include "dirent-util.h"
  15 #include "dns-domain.h"
  16 #include "event-util.h"
  17 #include "fd-util.h"
  18 #include "fileio.h"
  19 #include "hostname-util.h"
  20 #include "idn-util.h"
  21 #include "io-util.h"
  22 #include "missing_network.h"
  23 #include "missing_socket.h"
  24 #include "netlink-util.h"
  25 #include "ordered-set.h"
  26 #include "parse-util.h"
  27 #include "random-util.h"
  28 #include "resolved-bus.h"
  29 #include "resolved-conf.h"
  30 #include "resolved-dns-stub.h"
  31 #include "resolved-dnssd.h"
  32 #include "resolved-etc-hosts.h"
  33 #include "resolved-llmnr.h"
  34 #include "resolved-manager.h"
  35 #include "resolved-mdns.h"
  36 #include "resolved-resolv-conf.h"
  37 #include "resolved-util.h"
  38 #include "resolved-varlink.h"
  39 #include "socket-util.h"
  40 #include "string-table.h"
  41 #include "string-util.h"
  42 #include "utf8.h"
  43
  44 #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
  45
  46 static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
  47         Manager *m = userdata;
  48         uint16_t type;
  49         Link *l;
  50         int ifindex, r;
  51
  52         assert(rtnl);
  53         assert(m);
  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
 103 fail:
 104         log_warning_errno(r, "Failed to process RTNL link message: %m");
 105         return 0;
 106 }
 107
 108 static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
 109         Manager *m = userdata;
 110         union in_addr_union address;
 111         uint16_t type;
 112         int r, ifindex, family;
 113         LinkAddress *a;
 114         Link *l;
 115
 116         assert(rtnl);
 117         assert(mm);
 118         assert(m);
 119
 120         r = sd_netlink_message_get_type(mm, &type);
 121         if (r < 0)
 122                 goto fail;
 123
 124         r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
 125         if (r < 0)
 126                 goto fail;
 127
 128         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
 129         if (!l)
 130                 return 0;
 131
 132         r = sd_rtnl_message_addr_get_family(mm, &family);
 133         if (r < 0)
 134                 goto fail;
 135
 136         switch (family) {
 137
 138         case AF_INET:
 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);
 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
 187 fail:
 188         log_warning_errno(r, "Failed to process RTNL address message: %m");
 189         return 0;
 190 }
 191
 192 static int manager_rtnl_listen(Manager *m) {
 193         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 194         sd_netlink_message *i;
 195         int r;
 196
 197         assert(m);
 198
 199         /* First, subscribe to interfaces coming and going */
 200         r = sd_netlink_open(&m->rtnl);
 201         if (r < 0)
 202                 return r;
 203
 204         r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
 205         if (r < 0)
 206                 return r;
 207
 208         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
 209         if (r < 0)
 210                 return r;
 211
 212         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
 213         if (r < 0)
 214                 return r;
 215
 216         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
 217         if (r < 0)
 218                 return r;
 219
 220         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
 221         if (r < 0)
 222                 return r;
 223
 224         /* Then, enumerate all links */
 225         r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
 226         if (r < 0)
 227                 return r;
 228
 229         r = sd_netlink_message_request_dump(req, true);
 230         if (r < 0)
 231                 return r;
 232
 233         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 234         if (r < 0)
 235                 return r;
 236
 237         for (i = reply; i; i = sd_netlink_message_next(i)) {
 238                 r = manager_process_link(m->rtnl, i, m);
 239                 if (r < 0)
 240                         return r;
 241         }
 242
 243         req = sd_netlink_message_unref(req);
 244         reply = sd_netlink_message_unref(reply);
 245
 246         /* Finally, enumerate all addresses, too */
 247         r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
 248         if (r < 0)
 249                 return r;
 250
 251         r = sd_netlink_message_request_dump(req, true);
 252         if (r < 0)
 253                 return r;
 254
 255         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 256         if (r < 0)
 257                 return r;
 258
 259         for (i = reply; i; i = sd_netlink_message_next(i)) {
 260                 r = manager_process_address(m->rtnl, i, m);
 261                 if (r < 0)
 262                         return r;
 263         }
 264
 265         return r;
 266 }
 267
 268 static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 269         Manager *m = userdata;
 270         Link *l;
 271         int r;
 272
 273         assert(m);
 274
 275         sd_network_monitor_flush(m->network_monitor);
 276
 277         HASHMAP_FOREACH(l, m->links) {
 278                 r = link_update(l);
 279                 if (r < 0)
 280                         log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
 281         }
 282
 283         (void) manager_write_resolv_conf(m);
 284         (void) manager_send_changed(m, "DNS");
 285
 286         return 0;
 287 }
 288
 289 static int manager_network_monitor_listen(Manager *m) {
 290         int r, fd, events;
 291
 292         assert(m);
 293
 294         r = sd_network_monitor_new(&m->network_monitor, NULL);
 295         if (r < 0)
 296                 return r;
 297
 298         fd = sd_network_monitor_get_fd(m->network_monitor);
 299         if (fd < 0)
 300                 return fd;
 301
 302         events = sd_network_monitor_get_events(m->network_monitor);
 303         if (events < 0)
 304                 return events;
 305
 306         r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
 307         if (r < 0)
 308                 return r;
 309
 310         r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
 311         if (r < 0)
 312                 return r;
 313
 314         (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
 315
 316         return 0;
 317 }
 318
 319 static int manager_clock_change_listen(Manager *m);
 320
 321 static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
 322         Manager *m = userdata;
 323
 324         assert(m);
 325
 326         /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
 327          * the system clock into consideration, and if the clock changes the old validations might have been
 328          * wrong. Let's redo all validation with the new, correct time.
 329          *
 330          * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
 331          * we might be connected to a different network now without this being visible in a dropped link
 332          * carrier or so.) */
 333
 334         log_info("Clock change detected. Flushing caches.");
 335         manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
 336
 337         /* The clock change timerfd is unusable after it triggered once, create a new one. */
 338         return manager_clock_change_listen(m);
 339 }
 340
 341 static int manager_clock_change_listen(Manager *m) {
 342         int r;
 343
 344         assert(m);
 345
 346         m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
 347
 348         r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
 349         if (r < 0)
 350                 return log_error_errno(r, "Failed to create clock change event source: %m");
 351
 352         return 0;
 353 }
 354
 355 static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 356         _cleanup_free_ char *h = NULL, *n = NULL;
 357         int r;
 358
 359         assert(full_hostname);
 360         assert(llmnr_hostname);
 361         assert(mdns_hostname);
 362
 363         r = resolve_system_hostname(&h, &n);
 364         if (r < 0)
 365                 return r;
 366
 367         r = dns_name_concat(n, "local", 0, mdns_hostname);
 368         if (r < 0)
 369                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 370
 371         *llmnr_hostname = TAKE_PTR(n);
 372         *full_hostname = TAKE_PTR(h);
 373
 374         return 0;
 375 }
 376
 377 static char* fallback_hostname(void) {
 378
 379         /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
 380          * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
 381          * instead. */
 382
 383         _cleanup_free_ char *n = get_default_hostname();
 384         if (!n)
 385                 return NULL;
 386
 387         if (is_localhost(n))
 388                 return strdup("linux");
 389
 390         return TAKE_PTR(n);
 391 }
 392
 393 static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 394         _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
 395         char label[DNS_LABEL_MAX];
 396         const char *p;
 397         int r;
 398
 399         assert(full_hostname);
 400         assert(llmnr_hostname);
 401         assert(mdns_hostname);
 402
 403         p = h = fallback_hostname();
 404         if (!h)
 405                 return log_oom();
 406
 407         r = dns_label_unescape(&p, label, sizeof label, 0);
 408         if (r < 0)
 409                 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
 410
 411         assert(r > 0); /* The fallback hostname must have at least one label */
 412
 413         r = dns_label_escape_new(label, r, &n);
 414         if (r < 0)
 415                 return log_error_errno(r, "Failed to escape fallback hostname: %m");
 416
 417         r = dns_name_concat(n, "local", 0, &m);
 418         if (r < 0)
 419                 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
 420
 421         *llmnr_hostname = TAKE_PTR(n);
 422         *mdns_hostname = TAKE_PTR(m);
 423         *full_hostname = TAKE_PTR(h);
 424
 425         return 0;
 426 }
 427
 428 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 429         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 430         Manager *m = userdata;
 431         bool llmnr_hostname_changed;
 432         int r;
 433
 434         assert(m);
 435
 436         r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
 437         if (r < 0) {
 438                 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
 439                 return 0; /* ignore invalid hostnames */
 440         }
 441
 442         llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
 443         if (streq(full_hostname, m->full_hostname) &&
 444             !llmnr_hostname_changed &&
 445             streq(mdns_hostname, m->mdns_hostname))
 446                 return 0;
 447
 448         log_info("System hostname changed to '%s'.", full_hostname);
 449
 450         free_and_replace(m->full_hostname, full_hostname);
 451         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 452         free_and_replace(m->mdns_hostname, mdns_hostname);
 453
 454         manager_refresh_rrs(m);
 455         (void) manager_send_changed(m, "LLMNRHostname");
 456
 457         return 0;
 458 }
 459
 460 static int manager_watch_hostname(Manager *m) {
 461         int r;
 462
 463         assert(m);
 464
 465         m->hostname_fd = open("/proc/sys/kernel/hostname",
 466                               O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
 467         if (m->hostname_fd < 0) {
 468                 log_warning_errno(errno, "Failed to watch hostname: %m");
 469                 return 0;
 470         }
 471
 472         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 473         if (r < 0) {
 474                 if (r == -EPERM)
 475                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 476                         m->hostname_fd = safe_close(m->hostname_fd);
 477                 else
 478                         return log_error_errno(r, "Failed to add hostname event source: %m");
 479         }
 480
 481         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 482
 483         r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 484         if (r < 0) {
 485                 _cleanup_free_ char *d = NULL;
 486
 487                 d = fallback_hostname();
 488                 if (!d)
 489                         return log_oom();
 490
 491                 log_info("Defaulting to hostname '%s'.", d);
 492
 493                 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 494                 if (r < 0)
 495                         return r;
 496         } else
 497                 log_info("Using system hostname '%s'.", m->full_hostname);
 498
 499         return 0;
 500 }
 501
 502 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 503         _cleanup_free_ char *buffer = NULL;
 504         _cleanup_fclose_ FILE *f = NULL;
 505         Manager *m = userdata;
 506         size_t size = 0;
 507         Link *l;
 508
 509         assert(s);
 510         assert(si);
 511         assert(m);
 512
 513         f = open_memstream_unlocked(&buffer, &size);
 514         if (!f)
 515                 return log_oom();
 516
 517         LIST_FOREACH(scopes, scope, m->dns_scopes)
 518                 dns_scope_dump(scope, f);
 519
 520         LIST_FOREACH(servers, server, m->dns_servers)
 521                 dns_server_dump(server, f);
 522         LIST_FOREACH(servers, server, m->fallback_dns_servers)
 523                 dns_server_dump(server, f);
 524         HASHMAP_FOREACH(l, m->links)
 525                 LIST_FOREACH(servers, server, l->dns_servers)
 526                         dns_server_dump(server, f);
 527
 528         if (fflush_and_check(f) < 0)
 529                 return log_oom();
 530
 531         log_dump(LOG_INFO, buffer);
 532         return 0;
 533 }
 534
 535 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 536         Manager *m = userdata;
 537
 538         assert(s);
 539         assert(si);
 540         assert(m);
 541
 542         manager_flush_caches(m, LOG_INFO);
 543
 544         return 0;
 545 }
 546
 547 static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 548         Manager *m = userdata;
 549
 550         assert(s);
 551         assert(si);
 552         assert(m);
 553
 554         manager_reset_server_features(m);
 555         return 0;
 556 }
 557
 558 int manager_new(Manager **ret) {
 559         _cleanup_(manager_freep) Manager *m = NULL;
 560         int r;
 561
 562         assert(ret);
 563
 564         m = new(Manager, 1);
 565         if (!m)
 566                 return -ENOMEM;
 567
 568         *m = (Manager) {
 569                 .llmnr_ipv4_udp_fd = -1,
 570                 .llmnr_ipv6_udp_fd = -1,
 571                 .llmnr_ipv4_tcp_fd = -1,
 572                 .llmnr_ipv6_tcp_fd = -1,
 573                 .mdns_ipv4_fd = -1,
 574                 .mdns_ipv6_fd = -1,
 575                 .hostname_fd = -1,
 576
 577                 .llmnr_support = DEFAULT_LLMNR_MODE,
 578                 .mdns_support = DEFAULT_MDNS_MODE,
 579                 .dnssec_mode = DEFAULT_DNSSEC_MODE,
 580                 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
 581                 .enable_cache = DNS_CACHE_MODE_YES,
 582                 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
 583                 .read_resolv_conf = true,
 584                 .need_builtin_fallbacks = true,
 585                 .etc_hosts_last = USEC_INFINITY,
 586                 .read_etc_hosts = true,
 587         };
 588
 589         r = dns_trust_anchor_load(&m->trust_anchor);
 590         if (r < 0)
 591                 return r;
 592
 593         r = manager_parse_config_file(m);
 594         if (r < 0)
 595                 log_warning_errno(r, "Failed to parse configuration file: %m");
 596
 597 #if ENABLE_DNS_OVER_TLS
 598         r = dnstls_manager_init(m);
 599         if (r < 0)
 600                 return r;
 601 #endif
 602
 603         r = sd_event_default(&m->event);
 604         if (r < 0)
 605                 return r;
 606
 607         (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
 608         (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 609
 610         (void) sd_event_set_watchdog(m->event, true);
 611
 612         r = manager_watch_hostname(m);
 613         if (r < 0)
 614                 return r;
 615
 616         r = dnssd_load(m);
 617         if (r < 0)
 618                 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
 619
 620         r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
 621         if (r < 0)
 622                 return r;
 623
 624         r = manager_network_monitor_listen(m);
 625         if (r < 0)
 626                 return r;
 627
 628         r = manager_rtnl_listen(m);
 629         if (r < 0)
 630                 return r;
 631
 632         r = manager_clock_change_listen(m);
 633         if (r < 0)
 634                 return r;
 635
 636         r = manager_connect_bus(m);
 637         if (r < 0)
 638                 return r;
 639
 640         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 641         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 642         (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
 643
 644         manager_cleanup_saved_user(m);
 645
 646         *ret = TAKE_PTR(m);
 647
 648         return 0;
 649 }
 650
 651 int manager_start(Manager *m) {
 652         int r;
 653
 654         assert(m);
 655
 656         r = manager_dns_stub_start(m);
 657         if (r < 0)
 658                 return r;
 659
 660         r = manager_varlink_init(m);
 661         if (r < 0)
 662                 return r;
 663
 664         return 0;
 665 }
 666
 667 Manager *manager_free(Manager *m) {
 668         Link *l;
 669         DnssdService *s;
 670
 671         if (!m)
 672                 return NULL;
 673
 674         dns_server_unlink_all(m->dns_servers);
 675         dns_server_unlink_all(m->fallback_dns_servers);
 676         dns_search_domain_unlink_all(m->search_domains);
 677
 678         while ((l = hashmap_first(m->links)))
 679                link_free(l);
 680
 681         while (m->dns_queries)
 682                 dns_query_free(m->dns_queries);
 683
 684         m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
 685
 686         dns_scope_free(m->unicast_scope);
 687
 688         /* At this point only orphaned streams should remain. All others should have been freed already by their
 689          * owners */
 690         while (m->dns_streams)
 691                 dns_stream_unref(m->dns_streams);
 692
 693 #if ENABLE_DNS_OVER_TLS
 694         dnstls_manager_free(m);
 695 #endif
 696
 697         hashmap_free(m->links);
 698         hashmap_free(m->dns_transactions);
 699
 700         sd_event_source_unref(m->network_event_source);
 701         sd_network_monitor_unref(m->network_monitor);
 702
 703         sd_netlink_unref(m->rtnl);
 704         sd_event_source_unref(m->rtnl_event_source);
 705         sd_event_source_unref(m->clock_change_event_source);
 706
 707         manager_llmnr_stop(m);
 708         manager_mdns_stop(m);
 709         manager_dns_stub_stop(m);
 710         manager_varlink_done(m);
 711
 712         manager_socket_graveyard_clear(m);
 713
 714         ordered_set_free(m->dns_extra_stub_listeners);
 715
 716         bus_verify_polkit_async_registry_free(m->polkit_registry);
 717
 718         sd_bus_flush_close_unref(m->bus);
 719
 720         sd_event_source_unref(m->sigusr1_event_source);
 721         sd_event_source_unref(m->sigusr2_event_source);
 722         sd_event_source_unref(m->sigrtmin1_event_source);
 723
 724         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 725         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 726         dns_resource_key_unref(m->mdns_host_ipv4_key);
 727         dns_resource_key_unref(m->mdns_host_ipv6_key);
 728
 729         sd_event_source_unref(m->hostname_event_source);
 730         safe_close(m->hostname_fd);
 731
 732         sd_event_unref(m->event);
 733
 734         free(m->full_hostname);
 735         free(m->llmnr_hostname);
 736         free(m->mdns_hostname);
 737
 738         while ((s = hashmap_first(m->dnssd_services)))
 739                dnssd_service_free(s);
 740         hashmap_free(m->dnssd_services);
 741
 742         dns_trust_anchor_flush(&m->trust_anchor);
 743         manager_etc_hosts_flush(m);
 744
 745         return mfree(m);
 746 }
 747
 748 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 749         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 750         CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 751                          + CMSG_SPACE(int) /* ttl/hoplimit */
 752                          + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
 753         union sockaddr_union sa;
 754         struct iovec iov;
 755         struct msghdr mh = {
 756                 .msg_name = &sa.sa,
 757                 .msg_namelen = sizeof(sa),
 758                 .msg_iov = &iov,
 759                 .msg_iovlen = 1,
 760                 .msg_control = &control,
 761                 .msg_controllen = sizeof(control),
 762         };
 763         struct cmsghdr *cmsg;
 764         ssize_t ms, l;
 765         int r;
 766
 767         assert(m);
 768         assert(fd >= 0);
 769         assert(ret);
 770
 771         ms = next_datagram_size_fd(fd);
 772         if (ms < 0)
 773                 return ms;
 774
 775         r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
 776         if (r < 0)
 777                 return r;
 778
 779         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
 780
 781         l = recvmsg_safe(fd, &mh, 0);
 782         if (l < 0) {
 783                 if (ERRNO_IS_TRANSIENT(l))
 784                         return 0;
 785                 return l;
 786         }
 787         if (l == 0)
 788                 return 0;
 789
 790         assert(!(mh.msg_flags & MSG_TRUNC));
 791
 792         p->size = (size_t) l;
 793
 794         p->family = sa.sa.sa_family;
 795         p->ipproto = IPPROTO_UDP;
 796         if (p->family == AF_INET) {
 797                 p->sender.in = sa.in.sin_addr;
 798                 p->sender_port = be16toh(sa.in.sin_port);
 799         } else if (p->family == AF_INET6) {
 800                 p->sender.in6 = sa.in6.sin6_addr;
 801                 p->sender_port = be16toh(sa.in6.sin6_port);
 802                 p->ifindex = sa.in6.sin6_scope_id;
 803         } else
 804                 return -EAFNOSUPPORT;
 805
 806         p->timestamp = now(clock_boottime_or_monotonic());
 807
 808         CMSG_FOREACH(cmsg, &mh) {
 809
 810                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 811                         assert(p->family == AF_INET6);
 812
 813                         switch (cmsg->cmsg_type) {
 814
 815                         case IPV6_PKTINFO: {
 816                                 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 817
 818                                 if (p->ifindex <= 0)
 819                                         p->ifindex = i->ipi6_ifindex;
 820
 821                                 p->destination.in6 = i->ipi6_addr;
 822                                 break;
 823                         }
 824
 825                         case IPV6_HOPLIMIT:
 826                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 827                                 break;
 828
 829                         case IPV6_RECVFRAGSIZE:
 830                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 831                                 break;
 832                         }
 833                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 834                         assert(p->family == AF_INET);
 835
 836                         switch (cmsg->cmsg_type) {
 837
 838                         case IP_PKTINFO: {
 839                                 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
 840
 841                                 if (p->ifindex <= 0)
 842                                         p->ifindex = i->ipi_ifindex;
 843
 844                                 p->destination.in = i->ipi_addr;
 845                                 break;
 846                         }
 847
 848                         case IP_TTL:
 849                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 850                                 break;
 851
 852                         case IP_RECVFRAGSIZE:
 853                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 854                                 break;
 855                         }
 856                 }
 857         }
 858
 859         /* The Linux kernel sets the interface index to the loopback
 860          * device if the packet came from the local host since it
 861          * avoids the routing table in such a case. Let's unset the
 862          * interface index in such a case. */
 863         if (p->ifindex == LOOPBACK_IFINDEX)
 864                 p->ifindex = 0;
 865
 866         if (protocol != DNS_PROTOCOL_DNS) {
 867                 /* If we don't know the interface index still, we look for the
 868                  * first local interface with a matching address. Yuck! */
 869                 if (p->ifindex <= 0)
 870                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 871         }
 872
 873         if (DEBUG_LOGGING) {
 874                 _cleanup_free_ char *sender_address = NULL, *destination_address = NULL;
 875
 876                 (void) in_addr_to_string(p->family, &p->sender, &sender_address);
 877                 (void) in_addr_to_string(p->family, &p->destination, &destination_address);
 878
 879                 log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%i, fragsize=%zu, sender=%s, destination=%s",
 880                           dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize,
 881                           strna(sender_address), strna(destination_address));
 882         }
 883
 884         *ret = TAKE_PTR(p);
 885         return 1;
 886 }
 887
 888 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 889         int r;
 890
 891         assert(fd >= 0);
 892         assert(mh);
 893
 894         for (;;) {
 895                 if (sendmsg(fd, mh, flags) >= 0)
 896                         return 0;
 897
 898                 if (errno == EINTR)
 899                         continue;
 900
 901                 if (errno != EAGAIN)
 902                         return -errno;
 903
 904                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 905                 if (r < 0)
 906                         return r;
 907                 if (r == 0)
 908                         return -ETIMEDOUT;
 909         }
 910 }
 911
 912 static int write_loop(int fd, void *message, size_t length) {
 913         int r;
 914
 915         assert(fd >= 0);
 916         assert(message);
 917
 918         for (;;) {
 919                 if (write(fd, message, length) >= 0)
 920                         return 0;
 921
 922                 if (errno == EINTR)
 923                         continue;
 924
 925                 if (errno != EAGAIN)
 926                         return -errno;
 927
 928                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 929                 if (r < 0)
 930                         return r;
 931                 if (r == 0)
 932                         return -ETIMEDOUT;
 933         }
 934 }
 935
 936 int manager_write(Manager *m, int fd, DnsPacket *p) {
 937         int r;
 938
 939         log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
 940                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
 941                   DNS_PACKET_QR(p) ? "response" : "query",
 942                   DNS_PACKET_ID(p),
 943                   p->size);
 944
 945         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 946         if (r < 0)
 947                 return r;
 948
 949         return 0;
 950 }
 951
 952 static int manager_ipv4_send(
 953                 Manager *m,
 954                 int fd,
 955                 int ifindex,
 956                 const struct in_addr *destination,
 957                 uint16_t port,
 958                 const struct in_addr *source,
 959                 DnsPacket *p) {
 960
 961         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
 962         union sockaddr_union sa;
 963         struct iovec iov;
 964         struct msghdr mh = {
 965                 .msg_iov = &iov,
 966                 .msg_iovlen = 1,
 967                 .msg_name = &sa.sa,
 968                 .msg_namelen = sizeof(sa.in),
 969         };
 970
 971         assert(m);
 972         assert(fd >= 0);
 973         assert(destination);
 974         assert(port > 0);
 975         assert(p);
 976
 977         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
 978
 979         sa = (union sockaddr_union) {
 980                 .in.sin_family = AF_INET,
 981                 .in.sin_addr = *destination,
 982                 .in.sin_port = htobe16(port),
 983         };
 984
 985         if (ifindex > 0) {
 986                 struct cmsghdr *cmsg;
 987                 struct in_pktinfo *pi;
 988
 989                 mh.msg_control = &control;
 990                 mh.msg_controllen = sizeof(control);
 991
 992                 cmsg = CMSG_FIRSTHDR(&mh);
 993                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
 994                 cmsg->cmsg_level = IPPROTO_IP;
 995                 cmsg->cmsg_type = IP_PKTINFO;
 996
 997                 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
 998                 pi->ipi_ifindex = ifindex;
 999
1000                 if (source)
1001                         pi->ipi_spec_dst = *source;
1002         }
1003
1004         return sendmsg_loop(fd, &mh, 0);
1005 }
1006
1007 static int manager_ipv6_send(
1008                 Manager *m,
1009                 int fd,
1010                 int ifindex,
1011                 const struct in6_addr *destination,
1012                 uint16_t port,
1013                 const struct in6_addr *source,
1014                 DnsPacket *p) {
1015
1016         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1017         union sockaddr_union sa;
1018         struct iovec iov;
1019         struct msghdr mh = {
1020                 .msg_iov = &iov,
1021                 .msg_iovlen = 1,
1022                 .msg_name = &sa.sa,
1023                 .msg_namelen = sizeof(sa.in6),
1024         };
1025
1026         assert(m);
1027         assert(fd >= 0);
1028         assert(destination);
1029         assert(port > 0);
1030         assert(p);
1031
1032         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1033
1034         sa = (union sockaddr_union) {
1035                 .in6.sin6_family = AF_INET6,
1036                 .in6.sin6_addr = *destination,
1037                 .in6.sin6_port = htobe16(port),
1038                 .in6.sin6_scope_id = ifindex,
1039         };
1040
1041         if (ifindex > 0) {
1042                 struct cmsghdr *cmsg;
1043                 struct in6_pktinfo *pi;
1044
1045                 mh.msg_control = &control;
1046                 mh.msg_controllen = sizeof(control);
1047
1048                 cmsg = CMSG_FIRSTHDR(&mh);
1049                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1050                 cmsg->cmsg_level = IPPROTO_IPV6;
1051                 cmsg->cmsg_type = IPV6_PKTINFO;
1052
1053                 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1054                 pi->ipi6_ifindex = ifindex;
1055
1056                 if (source)
1057                         pi->ipi6_addr = *source;
1058         }
1059
1060         return sendmsg_loop(fd, &mh, 0);
1061 }
1062
1063 int manager_send(
1064                 Manager *m,
1065                 int fd,
1066                 int ifindex,
1067                 int family,
1068                 const union in_addr_union *destination,
1069                 uint16_t port,
1070                 const union in_addr_union *source,
1071                 DnsPacket *p) {
1072
1073         assert(m);
1074         assert(fd >= 0);
1075         assert(destination);
1076         assert(port > 0);
1077         assert(p);
1078
1079         log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1080                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
1081                   DNS_PACKET_QR(p) ? "response" : "query",
1082                   DNS_PACKET_ID(p),
1083                   ifindex, af_to_name(family),
1084                   p->size);
1085
1086         if (family == AF_INET)
1087                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1088         if (family == AF_INET6)
1089                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1090
1091         return -EAFNOSUPPORT;
1092 }
1093
1094 uint32_t manager_find_mtu(Manager *m) {
1095         uint32_t mtu = 0;
1096         Link *l;
1097
1098         /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1099          * works on all interfaces we know of that have an IP address associated */
1100
1101         HASHMAP_FOREACH(l, m->links) {
1102                 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1103                 if (!l->addresses)
1104                         continue;
1105
1106                 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1107                  * let's ignore this link. */
1108                 if (l->mtu < MIN(UDP4_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE,
1109                                  UDP6_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE))
1110                         continue;
1111
1112                 if (mtu <= 0 || l->mtu < mtu)
1113                         mtu = l->mtu;
1114         }
1115
1116         if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1117                 return 1500;
1118
1119         return mtu;
1120 }
1121
1122 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1123         LinkAddress *a;
1124
1125         assert(m);
1126
1127         if (!IN_SET(family, AF_INET, AF_INET6))
1128                 return 0;
1129
1130         if (!in_addr)
1131                 return 0;
1132
1133         a = manager_find_link_address(m, family, in_addr);
1134         if (a)
1135                 return a->link->ifindex;
1136
1137         return 0;
1138 }
1139
1140 void manager_refresh_rrs(Manager *m) {
1141         Link *l;
1142         DnssdService *s;
1143
1144         assert(m);
1145
1146         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1147         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1148         m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1149         m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1150
1151         HASHMAP_FOREACH(l, m->links)
1152                 link_add_rrs(l, true);
1153
1154         if (m->mdns_support == RESOLVE_SUPPORT_YES)
1155                 HASHMAP_FOREACH(s, m->dnssd_services)
1156                         if (dnssd_update_rrs(s) < 0)
1157                                 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1158
1159         HASHMAP_FOREACH(l, m->links)
1160                 link_add_rrs(l, false);
1161 }
1162
1163 static int manager_next_random_name(const char *old, char **ret_new) {
1164         const char *p;
1165         uint64_t u, a;
1166         char *n;
1167
1168         p = strchr(old, 0);
1169         assert(p);
1170
1171         while (p > old) {
1172                 if (!strchr(DIGITS, p[-1]))
1173                         break;
1174
1175                 p--;
1176         }
1177
1178         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1179                 u = 1;
1180
1181         /* Add a random number to the old value. This way we can avoid
1182          * that two hosts pick the same hostname, win on IPv4 and lose
1183          * on IPv6 (or vice versa), and pick the same hostname
1184          * replacement hostname, ad infinitum. We still want the
1185          * numbers to go up monotonically, hence we just add a random
1186          * value 1..10 */
1187
1188         random_bytes(&a, sizeof(a));
1189         u += 1 + a % 10;
1190
1191         if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1192                 return -ENOMEM;
1193
1194         *ret_new = n;
1195
1196         return 0;
1197 }
1198
1199 int manager_next_hostname(Manager *m) {
1200         _cleanup_free_ char *h = NULL, *k = NULL;
1201         int r;
1202
1203         assert(m);
1204
1205         r = manager_next_random_name(m->llmnr_hostname, &h);
1206         if (r < 0)
1207                 return r;
1208
1209         r = dns_name_concat(h, "local", 0, &k);
1210         if (r < 0)
1211                 return r;
1212
1213         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1214
1215         free_and_replace(m->llmnr_hostname, h);
1216         free_and_replace(m->mdns_hostname, k);
1217
1218         manager_refresh_rrs(m);
1219         (void) manager_send_changed(m, "LLMNRHostname");
1220
1221         return 0;
1222 }
1223
1224 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1225         Link *l;
1226
1227         assert(m);
1228
1229         if (!IN_SET(family, AF_INET, AF_INET6))
1230                 return NULL;
1231
1232         if (!in_addr)
1233                 return NULL;
1234
1235         HASHMAP_FOREACH(l, m->links) {
1236                 LinkAddress *a;
1237
1238                 a = link_find_address(l, family, in_addr);
1239                 if (a)
1240                         return a;
1241         }
1242
1243         return NULL;
1244 }
1245
1246 bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1247         assert(m);
1248         assert(p);
1249
1250         /* Let's see if this packet comes from an IP address we have on any local interface */
1251
1252         return !!manager_find_link_address(m, p->family, &p->sender);
1253 }
1254
1255 bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1256         DnsTransaction *t;
1257
1258         assert(m);
1259         assert(p);
1260
1261         /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1262          * one we just got. If so, it's almost definitely a packet loop of some kind. */
1263
1264         t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1265         if (!t)
1266                 return false;
1267
1268         return t->sent && dns_packet_equal(t->sent, p);
1269 }
1270
1271 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1272         Link *l;
1273
1274         assert(m);
1275         assert(p);
1276
1277         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1278         if (!l)
1279                 return NULL;
1280
1281         switch (p->protocol) {
1282         case DNS_PROTOCOL_LLMNR:
1283                 if (p->family == AF_INET)
1284                         return l->llmnr_ipv4_scope;
1285                 else if (p->family == AF_INET6)
1286                         return l->llmnr_ipv6_scope;
1287
1288                 break;
1289
1290         case DNS_PROTOCOL_MDNS:
1291                 if (p->family == AF_INET)
1292                         return l->mdns_ipv4_scope;
1293                 else if (p->family == AF_INET6)
1294                         return l->mdns_ipv6_scope;
1295
1296                 break;
1297
1298         default:
1299                 break;
1300         }
1301
1302         return NULL;
1303 }
1304
1305 void manager_verify_all(Manager *m) {
1306         assert(m);
1307
1308         LIST_FOREACH(scopes, s, m->dns_scopes)
1309                 dns_zone_verify_all(&s->zone);
1310 }
1311
1312 int manager_is_own_hostname(Manager *m, const char *name) {
1313         int r;
1314
1315         assert(m);
1316         assert(name);
1317
1318         if (m->llmnr_hostname) {
1319                 r = dns_name_equal(name, m->llmnr_hostname);
1320                 if (r != 0)
1321                         return r;
1322         }
1323
1324         if (m->mdns_hostname) {
1325                 r = dns_name_equal(name, m->mdns_hostname);
1326                 if (r != 0)
1327                         return r;
1328         }
1329
1330         if (m->full_hostname)
1331                 return dns_name_equal(name, m->full_hostname);
1332
1333         return 0;
1334 }
1335
1336 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1337         Link *l;
1338         int r;
1339
1340         assert(m);
1341         assert(dns);
1342
1343         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1344         if (r < 0)
1345                 return r;
1346
1347         /* First add the system-wide servers and domains */
1348         LIST_FOREACH(servers, s, m->dns_servers) {
1349                 r = ordered_set_put(*dns, s);
1350                 if (r == -EEXIST)
1351                         continue;
1352                 if (r < 0)
1353                         return r;
1354         }
1355
1356         /* Then, add the per-link servers */
1357         HASHMAP_FOREACH(l, m->links) {
1358                 LIST_FOREACH(servers, s, l->dns_servers) {
1359                         r = ordered_set_put(*dns, s);
1360                         if (r == -EEXIST)
1361                                 continue;
1362                         if (r < 0)
1363                                 return r;
1364                 }
1365         }
1366
1367         /* If we found nothing, add the fallback servers */
1368         if (ordered_set_isempty(*dns)) {
1369                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1370                         r = ordered_set_put(*dns, s);
1371                         if (r == -EEXIST)
1372                                 continue;
1373                         if (r < 0)
1374                                 return r;
1375                 }
1376         }
1377
1378         return 0;
1379 }
1380
1381 /* filter_route is a tri-state:
1382  *   < 0: no filtering
1383  *   = 0 or false: return only domains which should be used for searching
1384  *   > 0 or true: return only domains which are for routing only
1385  */
1386 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1387         Link *l;
1388         int r;
1389
1390         assert(m);
1391         assert(domains);
1392
1393         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1394         if (r < 0)
1395                 return r;
1396
1397         LIST_FOREACH(domains, d, m->search_domains) {
1398
1399                 if (filter_route >= 0 &&
1400                     d->route_only != !!filter_route)
1401                         continue;
1402
1403                 r = ordered_set_put(*domains, d->name);
1404                 if (r == -EEXIST)
1405                         continue;
1406                 if (r < 0)
1407                         return r;
1408         }
1409
1410         HASHMAP_FOREACH(l, m->links) {
1411
1412                 LIST_FOREACH(domains, d, l->search_domains) {
1413
1414                         if (filter_route >= 0 &&
1415                             d->route_only != !!filter_route)
1416                                 continue;
1417
1418                         r = ordered_set_put(*domains, d->name);
1419                         if (r == -EEXIST)
1420                                 continue;
1421                         if (r < 0)
1422                                 return r;
1423                 }
1424         }
1425
1426         return 0;
1427 }
1428
1429 DnssecMode manager_get_dnssec_mode(Manager *m) {
1430         assert(m);
1431
1432         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1433                 return m->dnssec_mode;
1434
1435         return DNSSEC_NO;
1436 }
1437
1438 bool manager_dnssec_supported(Manager *m) {
1439         DnsServer *server;
1440         Link *l;
1441
1442         assert(m);
1443
1444         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1445                 return false;
1446
1447         server = manager_get_dns_server(m);
1448         if (server && !dns_server_dnssec_supported(server))
1449                 return false;
1450
1451         HASHMAP_FOREACH(l, m->links)
1452                 if (!link_dnssec_supported(l))
1453                         return false;
1454
1455         return true;
1456 }
1457
1458 DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1459         assert(m);
1460
1461         if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1462                 return m->dns_over_tls_mode;
1463
1464         return DNS_OVER_TLS_NO;
1465 }
1466
1467 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1468
1469         assert(verdict >= 0);
1470         assert(verdict < _DNSSEC_VERDICT_MAX);
1471
1472         if (DEBUG_LOGGING) {
1473                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1474
1475                 log_debug("Found verdict for lookup %s: %s",
1476                           dns_resource_key_to_string(key, s, sizeof s),
1477                           dnssec_verdict_to_string(verdict));
1478         }
1479
1480         m->n_dnssec_verdict[verdict]++;
1481 }
1482
1483 bool manager_routable(Manager *m) {
1484         Link *l;
1485
1486         assert(m);
1487
1488         /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1489
1490         HASHMAP_FOREACH(l, m->links)
1491                 if (link_relevant(l, AF_UNSPEC, false))
1492                         return true;
1493
1494         return false;
1495 }
1496
1497 void manager_flush_caches(Manager *m, int log_level) {
1498         assert(m);
1499
1500         LIST_FOREACH(scopes, scope, m->dns_scopes)
1501                 dns_cache_flush(&scope->cache);
1502
1503         log_full(log_level, "Flushed all caches.");
1504 }
1505
1506 void manager_reset_server_features(Manager *m) {
1507         Link *l;
1508
1509         dns_server_reset_features_all(m->dns_servers);
1510         dns_server_reset_features_all(m->fallback_dns_servers);
1511
1512         HASHMAP_FOREACH(l, m->links)
1513                 dns_server_reset_features_all(l->dns_servers);
1514
1515         log_info("Resetting learnt feature levels on all servers.");
1516 }
1517
1518 void manager_cleanup_saved_user(Manager *m) {
1519         _cleanup_closedir_ DIR *d = NULL;
1520
1521         assert(m);
1522
1523         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1524          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1525          * be restarted without losing this data. */
1526
1527         d = opendir("/run/systemd/resolve/netif/");
1528         if (!d) {
1529                 if (errno == ENOENT)
1530                         return;
1531
1532                 log_warning_errno(errno, "Failed to open interface directory: %m");
1533                 return;
1534         }
1535
1536         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1537                 _cleanup_free_ char *p = NULL;
1538                 int ifindex;
1539                 Link *l;
1540
1541                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1542                         continue;
1543
1544                 if (dot_or_dot_dot(de->d_name))
1545                         continue;
1546
1547                 ifindex = parse_ifindex(de->d_name);
1548                 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1549                         goto rm;
1550
1551                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1552                 if (!l) /* link vanished */
1553                         goto rm;
1554
1555                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1556                         goto rm;
1557
1558                 continue;
1559
1560         rm:
1561                 p = path_join("/run/systemd/resolve/netif", de->d_name);
1562                 if (!p) {
1563                         log_oom();
1564                         return;
1565                 }
1566
1567                 (void) unlink(p);
1568         }
1569 }
1570
1571 bool manager_next_dnssd_names(Manager *m) {
1572         DnssdService *s;
1573         bool tried = false;
1574         int r;
1575
1576         assert(m);
1577
1578         HASHMAP_FOREACH(s, m->dnssd_services) {
1579                 _cleanup_free_ char * new_name = NULL;
1580
1581                 if (!s->withdrawn)
1582                         continue;
1583
1584                 r = manager_next_random_name(s->name_template, &new_name);
1585                 if (r < 0) {
1586                         log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1587                         continue;
1588                 }
1589
1590                 free_and_replace(s->name_template, new_name);
1591
1592                 s->withdrawn = false;
1593
1594                 tried = true;
1595         }
1596
1597         if (tried)
1598                 manager_refresh_rrs(m);
1599
1600         return tried;
1601 }
1602
1603 bool manager_server_is_stub(Manager *m, DnsServer *s) {
1604         DnsStubListenerExtra *l;
1605
1606         assert(m);
1607         assert(s);
1608
1609         /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1610          * extra careful, and check here again */
1611         if (s->family == AF_INET &&
1612             s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1613             dns_server_port(s) == 53)
1614                 return true;
1615
1616         /* Main reason to call this is to check server data against the extra listeners, and filter things
1617          * out. */
1618         ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1619                 if (s->family == l->family &&
1620                     in_addr_equal(s->family, &s->address, &l->address) &&
1621                     dns_server_port(s) == dns_stub_listener_extra_port(l))
1622                         return true;
1623
1624         return false;
1625 }
1626
1627 int socket_disable_pmtud(int fd, int af) {
1628         int r;
1629
1630         assert(fd >= 0);
1631
1632         if (af == AF_UNSPEC) {
1633                 r = socket_get_family(fd, &af);
1634                 if (r < 0)
1635                         return r;
1636         }
1637
1638         switch (af) {
1639
1640         case AF_INET: {
1641                 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1642                  * PMTU forgery vulnerabilities.
1643                  *
1644                  * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1645                  * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1646                  * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1647                  * discovery.
1648                  *
1649                  * This helps mitigating the PMTUD vulnerability described here:
1650                  *
1651                  * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1652                  *
1653                  * Similar logic is in place in most DNS servers.
1654                  *
1655                  * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1656                  * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1657                  * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1658                  * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1659                  * fragments seen — and if we need larger packets always go to TCP.
1660                  */
1661
1662                 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1663                 if (r < 0)
1664                         return r;
1665
1666                 return 0;
1667         }
1668
1669         case AF_INET6: {
1670                 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1671                  * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1672                  * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1673                  * because there's nothing that could be fragmented further anymore. */
1674
1675                 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1676                 if (r < 0)
1677                         return r;
1678
1679                 return 0;
1680         }
1681
1682         default:
1683                 return -EAFNOSUPPORT;
1684         }
1685 }