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 = ASSERT_PTR(userdata);
  48         uint16_t type;
  49         Link *l;
  50         int ifindex, r;
  51
  52         assert(rtnl);
  53         assert(mm);
  54
  55         r = sd_netlink_message_get_type(mm, &type);
  56         if (r < 0)
  57                 goto fail;
  58
  59         r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
  60         if (r < 0)
  61                 goto fail;
  62
  63         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
  64
  65         switch (type) {
  66
  67         case RTM_NEWLINK:{
  68                 bool is_new = !l;
  69
  70                 if (!l) {
  71                         r = link_new(m, &l, ifindex);
  72                         if (r < 0)
  73                                 goto fail;
  74                 }
  75
  76                 r = link_process_rtnl(l, mm);
  77                 if (r < 0)
  78                         goto fail;
  79
  80                 r = link_update(l);
  81                 if (r < 0)
  82                         goto fail;
  83
  84                 if (is_new)
  85                         log_debug("Found new link %i/%s", ifindex, l->ifname);
  86
  87                 break;
  88         }
  89
  90         case RTM_DELLINK:
  91                 if (l) {
  92                         log_debug("Removing link %i/%s", l->ifindex, l->ifname);
  93                         link_remove_user(l);
  94                         link_free(l);
  95                 }
  96
  97                 break;
  98         }
  99
 100         return 0;
 101
 102 fail:
 103         log_warning_errno(r, "Failed to process RTNL link message: %m");
 104         return 0;
 105 }
 106
 107 static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
 108         Manager *m = ASSERT_PTR(userdata);
 109         union in_addr_union address;
 110         uint16_t type;
 111         int r, ifindex, family;
 112         LinkAddress *a;
 113         Link *l;
 114
 115         assert(rtnl);
 116         assert(mm);
 117
 118         r = sd_netlink_message_get_type(mm, &type);
 119         if (r < 0)
 120                 goto fail;
 121
 122         r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
 123         if (r < 0)
 124                 goto fail;
 125
 126         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
 127         if (!l)
 128                 return 0;
 129
 130         r = sd_rtnl_message_addr_get_family(mm, &family);
 131         if (r < 0)
 132                 goto fail;
 133
 134         switch (family) {
 135
 136         case AF_INET:
 137                 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
 138                 if (r < 0) {
 139                         r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
 140                         if (r < 0)
 141                                 goto fail;
 142                 }
 143
 144                 break;
 145
 146         case AF_INET6:
 147                 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
 148                 if (r < 0) {
 149                         r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
 150                         if (r < 0)
 151                                 goto fail;
 152                 }
 153
 154                 break;
 155
 156         default:
 157                 return 0;
 158         }
 159
 160         a = link_find_address(l, family, &address);
 161
 162         switch (type) {
 163
 164         case RTM_NEWADDR:
 165
 166                 if (!a) {
 167                         r = link_address_new(l, &a, family, &address);
 168                         if (r < 0)
 169                                 return r;
 170                 }
 171
 172                 r = link_address_update_rtnl(a, mm);
 173                 if (r < 0)
 174                         return r;
 175
 176                 break;
 177
 178         case RTM_DELADDR:
 179                 link_address_free(a);
 180                 break;
 181         }
 182
 183         return 0;
 184
 185 fail:
 186         log_warning_errno(r, "Failed to process RTNL address message: %m");
 187         return 0;
 188 }
 189
 190 static int manager_rtnl_listen(Manager *m) {
 191         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 192         int r;
 193
 194         assert(m);
 195
 196         /* First, subscribe to interfaces coming and going */
 197         r = sd_netlink_open(&m->rtnl);
 198         if (r < 0)
 199                 return r;
 200
 201         r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
 202         if (r < 0)
 203                 return r;
 204
 205         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
 206         if (r < 0)
 207                 return r;
 208
 209         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
 210         if (r < 0)
 211                 return r;
 212
 213         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
 214         if (r < 0)
 215                 return r;
 216
 217         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
 218         if (r < 0)
 219                 return r;
 220
 221         /* Then, enumerate all links */
 222         r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
 223         if (r < 0)
 224                 return r;
 225
 226         r = sd_netlink_message_set_request_dump(req, true);
 227         if (r < 0)
 228                 return r;
 229
 230         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 231         if (r < 0)
 232                 return r;
 233
 234         for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
 235                 r = manager_process_link(m->rtnl, i, m);
 236                 if (r < 0)
 237                         return r;
 238         }
 239
 240         req = sd_netlink_message_unref(req);
 241         reply = sd_netlink_message_unref(reply);
 242
 243         /* Finally, enumerate all addresses, too */
 244         r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
 245         if (r < 0)
 246                 return r;
 247
 248         r = sd_netlink_message_set_request_dump(req, true);
 249         if (r < 0)
 250                 return r;
 251
 252         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 253         if (r < 0)
 254                 return r;
 255
 256         for (sd_netlink_message *i = reply; i; i = sd_netlink_message_next(i)) {
 257                 r = manager_process_address(m->rtnl, i, m);
 258                 if (r < 0)
 259                         return r;
 260         }
 261
 262         return r;
 263 }
 264
 265 static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 266         Manager *m = ASSERT_PTR(userdata);
 267         Link *l;
 268         int r;
 269
 270         sd_network_monitor_flush(m->network_monitor);
 271
 272         HASHMAP_FOREACH(l, m->links) {
 273                 r = link_update(l);
 274                 if (r < 0)
 275                         log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
 276         }
 277
 278         (void) manager_write_resolv_conf(m);
 279         (void) manager_send_changed(m, "DNS");
 280
 281         return 0;
 282 }
 283
 284 static int manager_network_monitor_listen(Manager *m) {
 285         int r, fd, events;
 286
 287         assert(m);
 288
 289         r = sd_network_monitor_new(&m->network_monitor, NULL);
 290         if (r < 0)
 291                 return r;
 292
 293         fd = sd_network_monitor_get_fd(m->network_monitor);
 294         if (fd < 0)
 295                 return fd;
 296
 297         events = sd_network_monitor_get_events(m->network_monitor);
 298         if (events < 0)
 299                 return events;
 300
 301         r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
 302         if (r < 0)
 303                 return r;
 304
 305         r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
 306         if (r < 0)
 307                 return r;
 308
 309         (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
 310
 311         return 0;
 312 }
 313
 314 static int manager_clock_change_listen(Manager *m);
 315
 316 static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
 317         Manager *m = ASSERT_PTR(userdata);
 318
 319         /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
 320          * the system clock into consideration, and if the clock changes the old validations might have been
 321          * wrong. Let's redo all validation with the new, correct time.
 322          *
 323          * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
 324          * we might be connected to a different network now without this being visible in a dropped link
 325          * carrier or so.) */
 326
 327         log_info("Clock change detected. Flushing caches.");
 328         manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
 329
 330         /* The clock change timerfd is unusable after it triggered once, create a new one. */
 331         return manager_clock_change_listen(m);
 332 }
 333
 334 static int manager_clock_change_listen(Manager *m) {
 335         int r;
 336
 337         assert(m);
 338
 339         m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
 340
 341         r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
 342         if (r < 0)
 343                 return log_error_errno(r, "Failed to create clock change event source: %m");
 344
 345         return 0;
 346 }
 347
 348 static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 349         _cleanup_free_ char *h = NULL, *n = NULL;
 350         int r;
 351
 352         assert(full_hostname);
 353         assert(llmnr_hostname);
 354         assert(mdns_hostname);
 355
 356         r = resolve_system_hostname(&h, &n);
 357         if (r < 0)
 358                 return r;
 359
 360         r = dns_name_concat(n, "local", 0, mdns_hostname);
 361         if (r < 0)
 362                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 363
 364         *llmnr_hostname = TAKE_PTR(n);
 365         *full_hostname = TAKE_PTR(h);
 366
 367         return 0;
 368 }
 369
 370 static char* fallback_hostname(void) {
 371
 372         /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
 373          * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
 374          * instead. */
 375
 376         _cleanup_free_ char *n = get_default_hostname();
 377         if (!n)
 378                 return NULL;
 379
 380         if (is_localhost(n))
 381                 return strdup("linux");
 382
 383         return TAKE_PTR(n);
 384 }
 385
 386 static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 387         _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
 388         char label[DNS_LABEL_MAX];
 389         const char *p;
 390         int r;
 391
 392         assert(full_hostname);
 393         assert(llmnr_hostname);
 394         assert(mdns_hostname);
 395
 396         p = h = fallback_hostname();
 397         if (!h)
 398                 return log_oom();
 399
 400         r = dns_label_unescape(&p, label, sizeof label, 0);
 401         if (r < 0)
 402                 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
 403
 404         assert(r > 0); /* The fallback hostname must have at least one label */
 405
 406         r = dns_label_escape_new(label, r, &n);
 407         if (r < 0)
 408                 return log_error_errno(r, "Failed to escape fallback hostname: %m");
 409
 410         r = dns_name_concat(n, "local", 0, &m);
 411         if (r < 0)
 412                 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
 413
 414         *llmnr_hostname = TAKE_PTR(n);
 415         *mdns_hostname = TAKE_PTR(m);
 416         *full_hostname = TAKE_PTR(h);
 417
 418         return 0;
 419 }
 420
 421 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 422         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 423         Manager *m = ASSERT_PTR(userdata);
 424         bool llmnr_hostname_changed;
 425         int r;
 426
 427         r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
 428         if (r < 0) {
 429                 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
 430                 return 0; /* ignore invalid hostnames */
 431         }
 432
 433         llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
 434         if (streq(full_hostname, m->full_hostname) &&
 435             !llmnr_hostname_changed &&
 436             streq(mdns_hostname, m->mdns_hostname))
 437                 return 0;
 438
 439         log_info("System hostname changed to '%s'.", full_hostname);
 440
 441         free_and_replace(m->full_hostname, full_hostname);
 442         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 443         free_and_replace(m->mdns_hostname, mdns_hostname);
 444
 445         manager_refresh_rrs(m);
 446         (void) manager_send_changed(m, "LLMNRHostname");
 447
 448         return 0;
 449 }
 450
 451 static int manager_watch_hostname(Manager *m) {
 452         int r;
 453
 454         assert(m);
 455
 456         m->hostname_fd = open("/proc/sys/kernel/hostname",
 457                               O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
 458         if (m->hostname_fd < 0) {
 459                 log_warning_errno(errno, "Failed to watch hostname: %m");
 460                 return 0;
 461         }
 462
 463         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 464         if (r < 0) {
 465                 if (r == -EPERM)
 466                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 467                         m->hostname_fd = safe_close(m->hostname_fd);
 468                 else
 469                         return log_error_errno(r, "Failed to add hostname event source: %m");
 470         }
 471
 472         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 473
 474         r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 475         if (r < 0) {
 476                 _cleanup_free_ char *d = NULL;
 477
 478                 d = fallback_hostname();
 479                 if (!d)
 480                         return log_oom();
 481
 482                 log_info("Defaulting to hostname '%s'.", d);
 483
 484                 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 485                 if (r < 0)
 486                         return r;
 487         } else
 488                 log_info("Using system hostname '%s'.", m->full_hostname);
 489
 490         return 0;
 491 }
 492
 493 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 494         _cleanup_free_ char *buffer = NULL;
 495         _cleanup_fclose_ FILE *f = NULL;
 496         Manager *m = ASSERT_PTR(userdata);
 497         size_t size = 0;
 498         Link *l;
 499
 500         assert(s);
 501         assert(si);
 502
 503         f = open_memstream_unlocked(&buffer, &size);
 504         if (!f)
 505                 return log_oom();
 506
 507         LIST_FOREACH(scopes, scope, m->dns_scopes)
 508                 dns_scope_dump(scope, f);
 509
 510         LIST_FOREACH(servers, server, m->dns_servers)
 511                 dns_server_dump(server, f);
 512         LIST_FOREACH(servers, server, m->fallback_dns_servers)
 513                 dns_server_dump(server, f);
 514         HASHMAP_FOREACH(l, m->links)
 515                 LIST_FOREACH(servers, server, l->dns_servers)
 516                         dns_server_dump(server, f);
 517
 518         if (fflush_and_check(f) < 0)
 519                 return log_oom();
 520
 521         log_dump(LOG_INFO, buffer);
 522         return 0;
 523 }
 524
 525 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 526         Manager *m = ASSERT_PTR(userdata);
 527
 528         assert(s);
 529         assert(si);
 530
 531         manager_flush_caches(m, LOG_INFO);
 532
 533         return 0;
 534 }
 535
 536 static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 537         Manager *m = ASSERT_PTR(userdata);
 538
 539         assert(s);
 540         assert(si);
 541
 542         manager_reset_server_features(m);
 543         return 0;
 544 }
 545
 546 int manager_new(Manager **ret) {
 547         _cleanup_(manager_freep) Manager *m = NULL;
 548         int r;
 549
 550         assert(ret);
 551
 552         m = new(Manager, 1);
 553         if (!m)
 554                 return -ENOMEM;
 555
 556         *m = (Manager) {
 557                 .llmnr_ipv4_udp_fd = -1,
 558                 .llmnr_ipv6_udp_fd = -1,
 559                 .llmnr_ipv4_tcp_fd = -1,
 560                 .llmnr_ipv6_tcp_fd = -1,
 561                 .mdns_ipv4_fd = -1,
 562                 .mdns_ipv6_fd = -1,
 563                 .hostname_fd = -1,
 564
 565                 .llmnr_support = DEFAULT_LLMNR_MODE,
 566                 .mdns_support = DEFAULT_MDNS_MODE,
 567                 .dnssec_mode = DEFAULT_DNSSEC_MODE,
 568                 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
 569                 .enable_cache = DNS_CACHE_MODE_YES,
 570                 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
 571                 .read_resolv_conf = true,
 572                 .need_builtin_fallbacks = true,
 573                 .etc_hosts_last = USEC_INFINITY,
 574                 .read_etc_hosts = true,
 575         };
 576
 577         r = dns_trust_anchor_load(&m->trust_anchor);
 578         if (r < 0)
 579                 return r;
 580
 581         r = manager_parse_config_file(m);
 582         if (r < 0)
 583                 log_warning_errno(r, "Failed to parse configuration file: %m");
 584
 585 #if ENABLE_DNS_OVER_TLS
 586         r = dnstls_manager_init(m);
 587         if (r < 0)
 588                 return r;
 589 #endif
 590
 591         r = sd_event_default(&m->event);
 592         if (r < 0)
 593                 return r;
 594
 595         (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
 596         (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 597
 598         (void) sd_event_set_watchdog(m->event, true);
 599
 600         r = manager_watch_hostname(m);
 601         if (r < 0)
 602                 return r;
 603
 604         r = dnssd_load(m);
 605         if (r < 0)
 606                 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
 607
 608         r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
 609         if (r < 0)
 610                 return r;
 611
 612         r = manager_network_monitor_listen(m);
 613         if (r < 0)
 614                 return r;
 615
 616         r = manager_rtnl_listen(m);
 617         if (r < 0)
 618                 return r;
 619
 620         r = manager_clock_change_listen(m);
 621         if (r < 0)
 622                 return r;
 623
 624         r = manager_connect_bus(m);
 625         if (r < 0)
 626                 return r;
 627
 628         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 629         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 630         (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
 631
 632         manager_cleanup_saved_user(m);
 633
 634         *ret = TAKE_PTR(m);
 635
 636         return 0;
 637 }
 638
 639 int manager_start(Manager *m) {
 640         int r;
 641
 642         assert(m);
 643
 644         r = manager_dns_stub_start(m);
 645         if (r < 0)
 646                 return r;
 647
 648         r = manager_varlink_init(m);
 649         if (r < 0)
 650                 return r;
 651
 652         return 0;
 653 }
 654
 655 Manager *manager_free(Manager *m) {
 656         Link *l;
 657         DnssdService *s;
 658
 659         if (!m)
 660                 return NULL;
 661
 662         dns_server_unlink_all(m->dns_servers);
 663         dns_server_unlink_all(m->fallback_dns_servers);
 664         dns_search_domain_unlink_all(m->search_domains);
 665
 666         while ((l = hashmap_first(m->links)))
 667                link_free(l);
 668
 669         while (m->dns_queries)
 670                 dns_query_free(m->dns_queries);
 671
 672         m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
 673
 674         dns_scope_free(m->unicast_scope);
 675
 676         /* At this point only orphaned streams should remain. All others should have been freed already by their
 677          * owners */
 678         while (m->dns_streams)
 679                 dns_stream_unref(m->dns_streams);
 680
 681 #if ENABLE_DNS_OVER_TLS
 682         dnstls_manager_free(m);
 683 #endif
 684
 685         hashmap_free(m->links);
 686         hashmap_free(m->dns_transactions);
 687
 688         sd_event_source_unref(m->network_event_source);
 689         sd_network_monitor_unref(m->network_monitor);
 690
 691         sd_netlink_unref(m->rtnl);
 692         sd_event_source_unref(m->rtnl_event_source);
 693         sd_event_source_unref(m->clock_change_event_source);
 694
 695         manager_llmnr_stop(m);
 696         manager_mdns_stop(m);
 697         manager_dns_stub_stop(m);
 698         manager_varlink_done(m);
 699
 700         manager_socket_graveyard_clear(m);
 701
 702         ordered_set_free(m->dns_extra_stub_listeners);
 703
 704         bus_verify_polkit_async_registry_free(m->polkit_registry);
 705
 706         sd_bus_flush_close_unref(m->bus);
 707
 708         sd_event_source_unref(m->sigusr1_event_source);
 709         sd_event_source_unref(m->sigusr2_event_source);
 710         sd_event_source_unref(m->sigrtmin1_event_source);
 711
 712         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 713         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 714         dns_resource_key_unref(m->mdns_host_ipv4_key);
 715         dns_resource_key_unref(m->mdns_host_ipv6_key);
 716
 717         sd_event_source_unref(m->hostname_event_source);
 718         safe_close(m->hostname_fd);
 719
 720         sd_event_unref(m->event);
 721
 722         free(m->full_hostname);
 723         free(m->llmnr_hostname);
 724         free(m->mdns_hostname);
 725
 726         while ((s = hashmap_first(m->dnssd_services)))
 727                dnssd_service_free(s);
 728         hashmap_free(m->dnssd_services);
 729
 730         dns_trust_anchor_flush(&m->trust_anchor);
 731         manager_etc_hosts_flush(m);
 732
 733         return mfree(m);
 734 }
 735
 736 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 737         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 738         CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 739                          + CMSG_SPACE(int) /* ttl/hoplimit */
 740                          + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
 741         union sockaddr_union sa;
 742         struct iovec iov;
 743         struct msghdr mh = {
 744                 .msg_name = &sa.sa,
 745                 .msg_namelen = sizeof(sa),
 746                 .msg_iov = &iov,
 747                 .msg_iovlen = 1,
 748                 .msg_control = &control,
 749                 .msg_controllen = sizeof(control),
 750         };
 751         struct cmsghdr *cmsg;
 752         ssize_t ms, l;
 753         int r;
 754
 755         assert(m);
 756         assert(fd >= 0);
 757         assert(ret);
 758
 759         ms = next_datagram_size_fd(fd);
 760         if (ms < 0)
 761                 return ms;
 762
 763         r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
 764         if (r < 0)
 765                 return r;
 766
 767         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
 768
 769         l = recvmsg_safe(fd, &mh, 0);
 770         if (l < 0) {
 771                 if (ERRNO_IS_TRANSIENT(l))
 772                         return 0;
 773                 return l;
 774         }
 775         if (l == 0)
 776                 return 0;
 777
 778         assert(!(mh.msg_flags & MSG_TRUNC));
 779
 780         p->size = (size_t) l;
 781
 782         p->family = sa.sa.sa_family;
 783         p->ipproto = IPPROTO_UDP;
 784         if (p->family == AF_INET) {
 785                 p->sender.in = sa.in.sin_addr;
 786                 p->sender_port = be16toh(sa.in.sin_port);
 787         } else if (p->family == AF_INET6) {
 788                 p->sender.in6 = sa.in6.sin6_addr;
 789                 p->sender_port = be16toh(sa.in6.sin6_port);
 790                 p->ifindex = sa.in6.sin6_scope_id;
 791         } else
 792                 return -EAFNOSUPPORT;
 793
 794         p->timestamp = now(CLOCK_BOOTTIME);
 795
 796         CMSG_FOREACH(cmsg, &mh) {
 797
 798                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 799                         assert(p->family == AF_INET6);
 800
 801                         switch (cmsg->cmsg_type) {
 802
 803                         case IPV6_PKTINFO: {
 804                                 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 805
 806                                 if (p->ifindex <= 0)
 807                                         p->ifindex = i->ipi6_ifindex;
 808
 809                                 p->destination.in6 = i->ipi6_addr;
 810                                 break;
 811                         }
 812
 813                         case IPV6_HOPLIMIT:
 814                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 815                                 break;
 816
 817                         case IPV6_RECVFRAGSIZE:
 818                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 819                                 break;
 820                         }
 821                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 822                         assert(p->family == AF_INET);
 823
 824                         switch (cmsg->cmsg_type) {
 825
 826                         case IP_PKTINFO: {
 827                                 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
 828
 829                                 if (p->ifindex <= 0)
 830                                         p->ifindex = i->ipi_ifindex;
 831
 832                                 p->destination.in = i->ipi_addr;
 833                                 break;
 834                         }
 835
 836                         case IP_TTL:
 837                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 838                                 break;
 839
 840                         case IP_RECVFRAGSIZE:
 841                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 842                                 break;
 843                         }
 844                 }
 845         }
 846
 847         /* The Linux kernel sets the interface index to the loopback
 848          * device if the packet came from the local host since it
 849          * avoids the routing table in such a case. Let's unset the
 850          * interface index in such a case. */
 851         if (p->ifindex == LOOPBACK_IFINDEX)
 852                 p->ifindex = 0;
 853
 854         if (protocol != DNS_PROTOCOL_DNS) {
 855                 /* If we don't know the interface index still, we look for the
 856                  * first local interface with a matching address. Yuck! */
 857                 if (p->ifindex <= 0)
 858                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 859         }
 860
 861         log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
 862                   dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize,
 863                   IN_ADDR_TO_STRING(p->family, &p->sender),
 864                   IN_ADDR_TO_STRING(p->family, &p->destination));
 865
 866         *ret = TAKE_PTR(p);
 867         return 1;
 868 }
 869
 870 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 871         usec_t end;
 872         int r;
 873
 874         assert(fd >= 0);
 875         assert(mh);
 876
 877         end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
 878
 879         for (;;) {
 880                 if (sendmsg(fd, mh, flags) >= 0)
 881                         return 0;
 882                 if (errno == EINTR)
 883                         continue;
 884                 if (errno != EAGAIN)
 885                         return -errno;
 886
 887                 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
 888                 if (r < 0) {
 889                         if (ERRNO_IS_TRANSIENT(r))
 890                                 continue;
 891                         return r;
 892                 }
 893                 if (r == 0)
 894                         return -ETIMEDOUT;
 895         }
 896 }
 897
 898 static int write_loop(int fd, void *message, size_t length) {
 899         usec_t end;
 900         int r;
 901
 902         assert(fd >= 0);
 903         assert(message);
 904
 905         end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
 906
 907         for (;;) {
 908                 if (write(fd, message, length) >= 0)
 909                         return 0;
 910                 if (errno == EINTR)
 911                         continue;
 912                 if (errno != EAGAIN)
 913                         return -errno;
 914
 915                 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
 916                 if (r < 0) {
 917                         if (ERRNO_IS_TRANSIENT(r))
 918                                 continue;
 919                         return r;
 920                 }
 921                 if (r == 0)
 922                         return -ETIMEDOUT;
 923         }
 924 }
 925
 926 int manager_write(Manager *m, int fd, DnsPacket *p) {
 927         int r;
 928
 929         log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
 930                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
 931                   DNS_PACKET_QR(p) ? "response" : "query",
 932                   DNS_PACKET_ID(p),
 933                   p->size);
 934
 935         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 936         if (r < 0)
 937                 return r;
 938
 939         return 0;
 940 }
 941
 942 static int manager_ipv4_send(
 943                 Manager *m,
 944                 int fd,
 945                 int ifindex,
 946                 const struct in_addr *destination,
 947                 uint16_t port,
 948                 const struct in_addr *source,
 949                 DnsPacket *p) {
 950
 951         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
 952         union sockaddr_union sa;
 953         struct iovec iov;
 954         struct msghdr mh = {
 955                 .msg_iov = &iov,
 956                 .msg_iovlen = 1,
 957                 .msg_name = &sa.sa,
 958                 .msg_namelen = sizeof(sa.in),
 959         };
 960
 961         assert(m);
 962         assert(fd >= 0);
 963         assert(destination);
 964         assert(port > 0);
 965         assert(p);
 966
 967         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
 968
 969         sa = (union sockaddr_union) {
 970                 .in.sin_family = AF_INET,
 971                 .in.sin_addr = *destination,
 972                 .in.sin_port = htobe16(port),
 973         };
 974
 975         if (ifindex > 0) {
 976                 struct cmsghdr *cmsg;
 977                 struct in_pktinfo *pi;
 978
 979                 mh.msg_control = &control;
 980                 mh.msg_controllen = sizeof(control);
 981
 982                 cmsg = CMSG_FIRSTHDR(&mh);
 983                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
 984                 cmsg->cmsg_level = IPPROTO_IP;
 985                 cmsg->cmsg_type = IP_PKTINFO;
 986
 987                 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
 988                 pi->ipi_ifindex = ifindex;
 989
 990                 if (source)
 991                         pi->ipi_spec_dst = *source;
 992         }
 993
 994         return sendmsg_loop(fd, &mh, 0);
 995 }
 996
 997 static int manager_ipv6_send(
 998                 Manager *m,
 999                 int fd,
1000                 int ifindex,
1001                 const struct in6_addr *destination,
1002                 uint16_t port,
1003                 const struct in6_addr *source,
1004                 DnsPacket *p) {
1005
1006         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1007         union sockaddr_union sa;
1008         struct iovec iov;
1009         struct msghdr mh = {
1010                 .msg_iov = &iov,
1011                 .msg_iovlen = 1,
1012                 .msg_name = &sa.sa,
1013                 .msg_namelen = sizeof(sa.in6),
1014         };
1015
1016         assert(m);
1017         assert(fd >= 0);
1018         assert(destination);
1019         assert(port > 0);
1020         assert(p);
1021
1022         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1023
1024         sa = (union sockaddr_union) {
1025                 .in6.sin6_family = AF_INET6,
1026                 .in6.sin6_addr = *destination,
1027                 .in6.sin6_port = htobe16(port),
1028                 .in6.sin6_scope_id = ifindex,
1029         };
1030
1031         if (ifindex > 0) {
1032                 struct cmsghdr *cmsg;
1033                 struct in6_pktinfo *pi;
1034
1035                 mh.msg_control = &control;
1036                 mh.msg_controllen = sizeof(control);
1037
1038                 cmsg = CMSG_FIRSTHDR(&mh);
1039                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1040                 cmsg->cmsg_level = IPPROTO_IPV6;
1041                 cmsg->cmsg_type = IPV6_PKTINFO;
1042
1043                 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1044                 pi->ipi6_ifindex = ifindex;
1045
1046                 if (source)
1047                         pi->ipi6_addr = *source;
1048         }
1049
1050         return sendmsg_loop(fd, &mh, 0);
1051 }
1052
1053 static int dns_question_to_json(DnsQuestion *q, JsonVariant **ret) {
1054         _cleanup_(json_variant_unrefp) JsonVariant *l = NULL;
1055         DnsResourceKey *key;
1056         int r;
1057
1058         assert(ret);
1059
1060         DNS_QUESTION_FOREACH(key, q) {
1061                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1062
1063                 r = dns_resource_key_to_json(key, &v);
1064                 if (r < 0)
1065                         return r;
1066
1067                 r = json_variant_append_array(&l, v);
1068                 if (r < 0)
1069                         return r;
1070         }
1071
1072         *ret = TAKE_PTR(l);
1073         return 0;
1074 }
1075
1076 int manager_monitor_send(
1077                 Manager *m,
1078                 int state,
1079                 int rcode,
1080                 int error,
1081                 DnsQuestion *question_idna,
1082                 DnsQuestion *question_utf8,
1083                 DnsQuestion *collected_questions,
1084                 DnsAnswer *answer) {
1085
1086         _cleanup_(json_variant_unrefp) JsonVariant *jquestion = NULL, *jcollected_questions = NULL, *janswer = NULL;
1087         _cleanup_(dns_question_unrefp) DnsQuestion *merged = NULL;
1088         Varlink *connection;
1089         DnsAnswerItem *rri;
1090         int r;
1091
1092         assert(m);
1093
1094         if (set_isempty(m->varlink_subscription))
1095                 return 0;
1096
1097         /* Merge both questions format into one */
1098         r = dns_question_merge(question_idna, question_utf8, &merged);
1099         if (r < 0)
1100                 return log_error_errno(r, "Failed to merge UTF8/IDNA questions: %m");
1101
1102         /* Convert the current primary question to JSON */
1103         r = dns_question_to_json(merged, &jquestion);
1104         if (r < 0)
1105                 return log_error_errno(r, "Failed to convert question to JSON: %m");
1106
1107         /* Generate a JSON array of the questions preceding the current one in the CNAME chain */
1108         r = dns_question_to_json(collected_questions, &jcollected_questions);
1109         if (r < 0)
1110                 return log_error_errno(r, "Failed to convert question to JSON: %m");
1111
1112         DNS_ANSWER_FOREACH_ITEM(rri, answer) {
1113                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL, *w = NULL;
1114
1115                 r = dns_resource_record_to_json(rri->rr, &v);
1116                 if (r < 0)
1117                         return log_error_errno(r, "Failed to convert answer resource record to JSON: %m");
1118
1119                 r = dns_resource_record_to_wire_format(rri->rr, /* canonical= */ false); /* don't use DNSSEC canonical format, since it removes casing, but we want that for DNS_SD compat */
1120                 if (r < 0)
1121                         return log_error_errno(r, "Failed to generate RR wire format: %m");
1122
1123                 r = json_build(&w, JSON_BUILD_OBJECT(
1124                                                JSON_BUILD_PAIR_CONDITION(v, "rr", JSON_BUILD_VARIANT(v)),
1125                                                JSON_BUILD_PAIR("raw", JSON_BUILD_BASE64(rri->rr->wire_format, rri->rr->wire_format_size)),
1126                                                JSON_BUILD_PAIR_CONDITION(rri->ifindex > 0, "ifindex", JSON_BUILD_INTEGER(rri->ifindex))));
1127                 if (r < 0)
1128                         return log_error_errno(r, "Failed to make answer RR object: %m");
1129
1130                 r = json_variant_append_array(&janswer, w);
1131                 if (r < 0)
1132                         return log_debug_errno(r, "Failed to append notification entry to array: %m");
1133         }
1134
1135         SET_FOREACH(connection, m->varlink_subscription) {
1136                 r = varlink_notifyb(connection,
1137                                     JSON_BUILD_OBJECT(JSON_BUILD_PAIR("state", JSON_BUILD_STRING(dns_transaction_state_to_string(state))),
1138                                                       JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_RCODE_FAILURE, "rcode", JSON_BUILD_INTEGER(rcode)),
1139                                                       JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_ERRNO, "errno", JSON_BUILD_INTEGER(error)),
1140                                                       JSON_BUILD_PAIR("question", JSON_BUILD_VARIANT(jquestion)),
1141                                                       JSON_BUILD_PAIR_CONDITION(jcollected_questions, "collectedQuestions", JSON_BUILD_VARIANT(jcollected_questions)),
1142                                                       JSON_BUILD_PAIR_CONDITION(janswer, "answer", JSON_BUILD_VARIANT(janswer))));
1143                 if (r < 0)
1144                         log_debug_errno(r, "Failed to send monitor event, ignoring: %m");
1145         }
1146
1147         return 0;
1148 }
1149
1150 int manager_send(
1151                 Manager *m,
1152                 int fd,
1153                 int ifindex,
1154                 int family,
1155                 const union in_addr_union *destination,
1156                 uint16_t port,
1157                 const union in_addr_union *source,
1158                 DnsPacket *p) {
1159
1160         assert(m);
1161         assert(fd >= 0);
1162         assert(destination);
1163         assert(port > 0);
1164         assert(p);
1165
1166         log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1167                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
1168                   DNS_PACKET_QR(p) ? "response" : "query",
1169                   DNS_PACKET_ID(p),
1170                   ifindex, af_to_name(family),
1171                   p->size);
1172
1173         if (family == AF_INET)
1174                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1175         if (family == AF_INET6)
1176                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1177
1178         return -EAFNOSUPPORT;
1179 }
1180
1181 uint32_t manager_find_mtu(Manager *m) {
1182         uint32_t mtu = 0;
1183         Link *l;
1184
1185         /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1186          * works on all interfaces we know of that have an IP address associated */
1187
1188         HASHMAP_FOREACH(l, m->links) {
1189                 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1190                 if (!l->addresses)
1191                         continue;
1192
1193                 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1194                  * let's ignore this link. */
1195                 if (l->mtu < MIN(UDP4_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE,
1196                                  UDP6_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE))
1197                         continue;
1198
1199                 if (mtu <= 0 || l->mtu < mtu)
1200                         mtu = l->mtu;
1201         }
1202
1203         if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1204                 return 1500;
1205
1206         return mtu;
1207 }
1208
1209 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1210         LinkAddress *a;
1211
1212         assert(m);
1213
1214         if (!IN_SET(family, AF_INET, AF_INET6))
1215                 return 0;
1216
1217         if (!in_addr)
1218                 return 0;
1219
1220         a = manager_find_link_address(m, family, in_addr);
1221         if (a)
1222                 return a->link->ifindex;
1223
1224         return 0;
1225 }
1226
1227 void manager_refresh_rrs(Manager *m) {
1228         Link *l;
1229         DnssdService *s;
1230
1231         assert(m);
1232
1233         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1234         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1235         m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1236         m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1237
1238         HASHMAP_FOREACH(l, m->links)
1239                 link_add_rrs(l, true);
1240
1241         if (m->mdns_support == RESOLVE_SUPPORT_YES)
1242                 HASHMAP_FOREACH(s, m->dnssd_services)
1243                         if (dnssd_update_rrs(s) < 0)
1244                                 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1245
1246         HASHMAP_FOREACH(l, m->links)
1247                 link_add_rrs(l, false);
1248 }
1249
1250 static int manager_next_random_name(const char *old, char **ret_new) {
1251         const char *p;
1252         uint64_t u, a;
1253         char *n;
1254
1255         p = strchr(old, 0);
1256         assert(p);
1257
1258         while (p > old) {
1259                 if (!ascii_isdigit(p[-1]))
1260                         break;
1261
1262                 p--;
1263         }
1264
1265         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1266                 u = 1;
1267
1268         /* Add a random number to the old value. This way we can avoid
1269          * that two hosts pick the same hostname, win on IPv4 and lose
1270          * on IPv6 (or vice versa), and pick the same hostname
1271          * replacement hostname, ad infinitum. We still want the
1272          * numbers to go up monotonically, hence we just add a random
1273          * value 1..10 */
1274
1275         random_bytes(&a, sizeof(a));
1276         u += 1 + a % 10;
1277
1278         if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1279                 return -ENOMEM;
1280
1281         *ret_new = n;
1282
1283         return 0;
1284 }
1285
1286 int manager_next_hostname(Manager *m) {
1287         _cleanup_free_ char *h = NULL, *k = NULL;
1288         int r;
1289
1290         assert(m);
1291
1292         r = manager_next_random_name(m->llmnr_hostname, &h);
1293         if (r < 0)
1294                 return r;
1295
1296         r = dns_name_concat(h, "local", 0, &k);
1297         if (r < 0)
1298                 return r;
1299
1300         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1301
1302         free_and_replace(m->llmnr_hostname, h);
1303         free_and_replace(m->mdns_hostname, k);
1304
1305         manager_refresh_rrs(m);
1306         (void) manager_send_changed(m, "LLMNRHostname");
1307
1308         return 0;
1309 }
1310
1311 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1312         Link *l;
1313
1314         assert(m);
1315
1316         if (!IN_SET(family, AF_INET, AF_INET6))
1317                 return NULL;
1318
1319         if (!in_addr)
1320                 return NULL;
1321
1322         HASHMAP_FOREACH(l, m->links) {
1323                 LinkAddress *a;
1324
1325                 a = link_find_address(l, family, in_addr);
1326                 if (a)
1327                         return a;
1328         }
1329
1330         return NULL;
1331 }
1332
1333 bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1334         assert(m);
1335         assert(p);
1336
1337         /* Let's see if this packet comes from an IP address we have on any local interface */
1338
1339         return !!manager_find_link_address(m, p->family, &p->sender);
1340 }
1341
1342 bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1343         DnsTransaction *t;
1344
1345         assert(m);
1346         assert(p);
1347
1348         /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1349          * one we just got. If so, it's almost definitely a packet loop of some kind. */
1350
1351         t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1352         if (!t)
1353                 return false;
1354
1355         return t->sent && dns_packet_equal(t->sent, p);
1356 }
1357
1358 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1359         Link *l;
1360
1361         assert(m);
1362         assert(p);
1363
1364         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1365         if (!l)
1366                 return NULL;
1367
1368         switch (p->protocol) {
1369         case DNS_PROTOCOL_LLMNR:
1370                 if (p->family == AF_INET)
1371                         return l->llmnr_ipv4_scope;
1372                 else if (p->family == AF_INET6)
1373                         return l->llmnr_ipv6_scope;
1374
1375                 break;
1376
1377         case DNS_PROTOCOL_MDNS:
1378                 if (p->family == AF_INET)
1379                         return l->mdns_ipv4_scope;
1380                 else if (p->family == AF_INET6)
1381                         return l->mdns_ipv6_scope;
1382
1383                 break;
1384
1385         default:
1386                 break;
1387         }
1388
1389         return NULL;
1390 }
1391
1392 void manager_verify_all(Manager *m) {
1393         assert(m);
1394
1395         LIST_FOREACH(scopes, s, m->dns_scopes)
1396                 dns_zone_verify_all(&s->zone);
1397 }
1398
1399 int manager_is_own_hostname(Manager *m, const char *name) {
1400         int r;
1401
1402         assert(m);
1403         assert(name);
1404
1405         if (m->llmnr_hostname) {
1406                 r = dns_name_equal(name, m->llmnr_hostname);
1407                 if (r != 0)
1408                         return r;
1409         }
1410
1411         if (m->mdns_hostname) {
1412                 r = dns_name_equal(name, m->mdns_hostname);
1413                 if (r != 0)
1414                         return r;
1415         }
1416
1417         if (m->full_hostname)
1418                 return dns_name_equal(name, m->full_hostname);
1419
1420         return 0;
1421 }
1422
1423 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1424         Link *l;
1425         int r;
1426
1427         assert(m);
1428         assert(dns);
1429
1430         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1431         if (r < 0)
1432                 return r;
1433
1434         /* First add the system-wide servers and domains */
1435         LIST_FOREACH(servers, s, m->dns_servers) {
1436                 r = ordered_set_put(*dns, s);
1437                 if (r == -EEXIST)
1438                         continue;
1439                 if (r < 0)
1440                         return r;
1441         }
1442
1443         /* Then, add the per-link servers */
1444         HASHMAP_FOREACH(l, m->links) {
1445                 LIST_FOREACH(servers, s, l->dns_servers) {
1446                         r = ordered_set_put(*dns, s);
1447                         if (r == -EEXIST)
1448                                 continue;
1449                         if (r < 0)
1450                                 return r;
1451                 }
1452         }
1453
1454         /* If we found nothing, add the fallback servers */
1455         if (ordered_set_isempty(*dns)) {
1456                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1457                         r = ordered_set_put(*dns, s);
1458                         if (r == -EEXIST)
1459                                 continue;
1460                         if (r < 0)
1461                                 return r;
1462                 }
1463         }
1464
1465         return 0;
1466 }
1467
1468 /* filter_route is a tri-state:
1469  *   < 0: no filtering
1470  *   = 0 or false: return only domains which should be used for searching
1471  *   > 0 or true: return only domains which are for routing only
1472  */
1473 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1474         Link *l;
1475         int r;
1476
1477         assert(m);
1478         assert(domains);
1479
1480         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1481         if (r < 0)
1482                 return r;
1483
1484         LIST_FOREACH(domains, d, m->search_domains) {
1485
1486                 if (filter_route >= 0 &&
1487                     d->route_only != !!filter_route)
1488                         continue;
1489
1490                 r = ordered_set_put(*domains, d->name);
1491                 if (r == -EEXIST)
1492                         continue;
1493                 if (r < 0)
1494                         return r;
1495         }
1496
1497         HASHMAP_FOREACH(l, m->links) {
1498
1499                 LIST_FOREACH(domains, d, l->search_domains) {
1500
1501                         if (filter_route >= 0 &&
1502                             d->route_only != !!filter_route)
1503                                 continue;
1504
1505                         r = ordered_set_put(*domains, d->name);
1506                         if (r == -EEXIST)
1507                                 continue;
1508                         if (r < 0)
1509                                 return r;
1510                 }
1511         }
1512
1513         return 0;
1514 }
1515
1516 DnssecMode manager_get_dnssec_mode(Manager *m) {
1517         assert(m);
1518
1519         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1520                 return m->dnssec_mode;
1521
1522         return DNSSEC_NO;
1523 }
1524
1525 bool manager_dnssec_supported(Manager *m) {
1526         DnsServer *server;
1527         Link *l;
1528
1529         assert(m);
1530
1531         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1532                 return false;
1533
1534         server = manager_get_dns_server(m);
1535         if (server && !dns_server_dnssec_supported(server))
1536                 return false;
1537
1538         HASHMAP_FOREACH(l, m->links)
1539                 if (!link_dnssec_supported(l))
1540                         return false;
1541
1542         return true;
1543 }
1544
1545 DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1546         assert(m);
1547
1548         if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1549                 return m->dns_over_tls_mode;
1550
1551         return DNS_OVER_TLS_NO;
1552 }
1553
1554 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1555
1556         assert(verdict >= 0);
1557         assert(verdict < _DNSSEC_VERDICT_MAX);
1558
1559         if (DEBUG_LOGGING) {
1560                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1561
1562                 log_debug("Found verdict for lookup %s: %s",
1563                           dns_resource_key_to_string(key, s, sizeof s),
1564                           dnssec_verdict_to_string(verdict));
1565         }
1566
1567         m->n_dnssec_verdict[verdict]++;
1568 }
1569
1570 bool manager_routable(Manager *m) {
1571         Link *l;
1572
1573         assert(m);
1574
1575         /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1576
1577         HASHMAP_FOREACH(l, m->links)
1578                 if (link_relevant(l, AF_UNSPEC, false))
1579                         return true;
1580
1581         return false;
1582 }
1583
1584 void manager_flush_caches(Manager *m, int log_level) {
1585         assert(m);
1586
1587         LIST_FOREACH(scopes, scope, m->dns_scopes)
1588                 dns_cache_flush(&scope->cache);
1589
1590         log_full(log_level, "Flushed all caches.");
1591 }
1592
1593 void manager_reset_server_features(Manager *m) {
1594         Link *l;
1595
1596         dns_server_reset_features_all(m->dns_servers);
1597         dns_server_reset_features_all(m->fallback_dns_servers);
1598
1599         HASHMAP_FOREACH(l, m->links)
1600                 dns_server_reset_features_all(l->dns_servers);
1601
1602         log_info("Resetting learnt feature levels on all servers.");
1603 }
1604
1605 void manager_cleanup_saved_user(Manager *m) {
1606         _cleanup_closedir_ DIR *d = NULL;
1607
1608         assert(m);
1609
1610         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1611          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1612          * be restarted without losing this data. */
1613
1614         d = opendir("/run/systemd/resolve/netif/");
1615         if (!d) {
1616                 if (errno == ENOENT)
1617                         return;
1618
1619                 log_warning_errno(errno, "Failed to open interface directory: %m");
1620                 return;
1621         }
1622
1623         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1624                 _cleanup_free_ char *p = NULL;
1625                 int ifindex;
1626                 Link *l;
1627
1628                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1629                         continue;
1630
1631                 if (dot_or_dot_dot(de->d_name))
1632                         continue;
1633
1634                 ifindex = parse_ifindex(de->d_name);
1635                 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1636                         goto rm;
1637
1638                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1639                 if (!l) /* link vanished */
1640                         goto rm;
1641
1642                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1643                         goto rm;
1644
1645                 continue;
1646
1647         rm:
1648                 p = path_join("/run/systemd/resolve/netif", de->d_name);
1649                 if (!p) {
1650                         log_oom();
1651                         return;
1652                 }
1653
1654                 (void) unlink(p);
1655         }
1656 }
1657
1658 bool manager_next_dnssd_names(Manager *m) {
1659         DnssdService *s;
1660         bool tried = false;
1661         int r;
1662
1663         assert(m);
1664
1665         HASHMAP_FOREACH(s, m->dnssd_services) {
1666                 _cleanup_free_ char * new_name = NULL;
1667
1668                 if (!s->withdrawn)
1669                         continue;
1670
1671                 r = manager_next_random_name(s->name_template, &new_name);
1672                 if (r < 0) {
1673                         log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1674                         continue;
1675                 }
1676
1677                 free_and_replace(s->name_template, new_name);
1678
1679                 s->withdrawn = false;
1680
1681                 tried = true;
1682         }
1683
1684         if (tried)
1685                 manager_refresh_rrs(m);
1686
1687         return tried;
1688 }
1689
1690 bool manager_server_is_stub(Manager *m, DnsServer *s) {
1691         DnsStubListenerExtra *l;
1692
1693         assert(m);
1694         assert(s);
1695
1696         /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1697          * extra careful, and check here again */
1698         if (s->family == AF_INET &&
1699             s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1700             dns_server_port(s) == 53)
1701                 return true;
1702
1703         /* Main reason to call this is to check server data against the extra listeners, and filter things
1704          * out. */
1705         ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1706                 if (s->family == l->family &&
1707                     in_addr_equal(s->family, &s->address, &l->address) &&
1708                     dns_server_port(s) == dns_stub_listener_extra_port(l))
1709                         return true;
1710
1711         return false;
1712 }
1713
1714 int socket_disable_pmtud(int fd, int af) {
1715         int r;
1716
1717         assert(fd >= 0);
1718
1719         if (af == AF_UNSPEC) {
1720                 r = socket_get_family(fd, &af);
1721                 if (r < 0)
1722                         return r;
1723         }
1724
1725         switch (af) {
1726
1727         case AF_INET: {
1728                 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1729                  * PMTU forgery vulnerabilities.
1730                  *
1731                  * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1732                  * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1733                  * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1734                  * discovery.
1735                  *
1736                  * This helps mitigating the PMTUD vulnerability described here:
1737                  *
1738                  * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1739                  *
1740                  * Similar logic is in place in most DNS servers.
1741                  *
1742                  * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1743                  * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1744                  * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1745                  * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1746                  * fragments seen — and if we need larger packets always go to TCP.
1747                  */
1748
1749                 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1750                 if (r < 0)
1751                         return r;
1752
1753                 return 0;
1754         }
1755
1756         case AF_INET6: {
1757                 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1758                  * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1759                  * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1760                  * because there's nothing that could be fragmented further anymore. */
1761
1762                 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1763                 if (r < 0)
1764                         return r;
1765
1766                 return 0;
1767         }
1768
1769         default:
1770                 return -EAFNOSUPPORT;
1771         }
1772 }