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 "iovec-util.h"
  23 #include "memstream-util.h"
  24 #include "missing_network.h"
  25 #include "missing_socket.h"
  26 #include "netlink-util.h"
  27 #include "ordered-set.h"
  28 #include "parse-util.h"
  29 #include "random-util.h"
  30 #include "resolved-bus.h"
  31 #include "resolved-conf.h"
  32 #include "resolved-dns-stub.h"
  33 #include "resolved-dnssd.h"
  34 #include "resolved-etc-hosts.h"
  35 #include "resolved-llmnr.h"
  36 #include "resolved-manager.h"
  37 #include "resolved-mdns.h"
  38 #include "resolved-resolv-conf.h"
  39 #include "resolved-util.h"
  40 #include "resolved-varlink.h"
  41 #include "socket-util.h"
  42 #include "string-table.h"
  43 #include "string-util.h"
  44 #include "utf8.h"
  45
  46 #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
  47
  48 static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
  49         Manager *m = ASSERT_PTR(userdata);
  50         uint16_t type;
  51         Link *l;
  52         int ifindex, r;
  53
  54         assert(rtnl);
  55         assert(mm);
  56
  57         r = sd_netlink_message_get_type(mm, &type);
  58         if (r < 0)
  59                 goto fail;
  60
  61         r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
  62         if (r < 0)
  63                 goto fail;
  64
  65         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
  66
  67         switch (type) {
  68
  69         case RTM_NEWLINK:{
  70                 bool is_new = !l;
  71
  72                 if (!l) {
  73                         r = link_new(m, &l, ifindex);
  74                         if (r < 0)
  75                                 goto fail;
  76                 }
  77
  78                 r = link_process_rtnl(l, mm);
  79                 if (r < 0)
  80                         goto fail;
  81
  82                 r = link_update(l);
  83                 if (r < 0)
  84                         goto fail;
  85
  86                 if (is_new)
  87                         log_debug("Found new link %i/%s", ifindex, l->ifname);
  88
  89                 break;
  90         }
  91
  92         case RTM_DELLINK:
  93                 if (l) {
  94                         log_debug("Removing link %i/%s", l->ifindex, l->ifname);
  95                         link_remove_user(l);
  96                         link_free(l);
  97                 }
  98
  99                 break;
 100         }
 101
 102         return 0;
 103
 104 fail:
 105         log_warning_errno(r, "Failed to process RTNL link message: %m");
 106         return 0;
 107 }
 108
 109 static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
 110         Manager *m = ASSERT_PTR(userdata);
 111         union in_addr_union address, broadcast = {};
 112         uint16_t type;
 113         int r, ifindex, family;
 114         LinkAddress *a;
 115         Link *l;
 116
 117         assert(rtnl);
 118         assert(mm);
 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                 sd_netlink_message_read_in_addr(mm, IFA_BROADCAST, &broadcast.in);
 140                 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
 141                 if (r < 0) {
 142                         r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
 143                         if (r < 0)
 144                                 goto fail;
 145                 }
 146
 147                 break;
 148
 149         case AF_INET6:
 150                 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
 151                 if (r < 0) {
 152                         r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
 153                         if (r < 0)
 154                                 goto fail;
 155                 }
 156
 157                 break;
 158
 159         default:
 160                 return 0;
 161         }
 162
 163         a = link_find_address(l, family, &address);
 164
 165         switch (type) {
 166
 167         case RTM_NEWADDR:
 168
 169                 if (!a) {
 170                         r = link_address_new(l, &a, family, &address, &broadcast);
 171                         if (r < 0)
 172                                 return r;
 173                 }
 174
 175                 r = link_address_update_rtnl(a, mm);
 176                 if (r < 0)
 177                         return r;
 178
 179                 break;
 180
 181         case RTM_DELADDR:
 182                 link_address_free(a);
 183                 break;
 184         }
 185
 186         return 0;
 187
 188 fail:
 189         log_warning_errno(r, "Failed to process RTNL address message: %m");
 190         return 0;
 191 }
 192
 193 static int manager_rtnl_listen(Manager *m) {
 194         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 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_set_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 (sd_netlink_message *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_set_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 (sd_netlink_message *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 = ASSERT_PTR(userdata);
 270         Link *l;
 271         int r;
 272
 273         sd_network_monitor_flush(m->network_monitor);
 274
 275         HASHMAP_FOREACH(l, m->links) {
 276                 r = link_update(l);
 277                 if (r < 0)
 278                         log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
 279         }
 280
 281         (void) manager_write_resolv_conf(m);
 282         (void) manager_send_changed(m, "DNS");
 283
 284         return 0;
 285 }
 286
 287 static int manager_network_monitor_listen(Manager *m) {
 288         int r, fd, events;
 289
 290         assert(m);
 291
 292         r = sd_network_monitor_new(&m->network_monitor, NULL);
 293         if (r < 0)
 294                 return r;
 295
 296         fd = sd_network_monitor_get_fd(m->network_monitor);
 297         if (fd < 0)
 298                 return fd;
 299
 300         events = sd_network_monitor_get_events(m->network_monitor);
 301         if (events < 0)
 302                 return events;
 303
 304         r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
 305         if (r < 0)
 306                 return r;
 307
 308         r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
 309         if (r < 0)
 310                 return r;
 311
 312         (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
 313
 314         return 0;
 315 }
 316
 317 static int manager_clock_change_listen(Manager *m);
 318
 319 static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
 320         Manager *m = ASSERT_PTR(userdata);
 321
 322         /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
 323          * the system clock into consideration, and if the clock changes the old validations might have been
 324          * wrong. Let's redo all validation with the new, correct time.
 325          *
 326          * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
 327          * we might be connected to a different network now without this being visible in a dropped link
 328          * carrier or so.) */
 329
 330         log_info("Clock change detected. Flushing caches.");
 331         manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
 332
 333         /* The clock change timerfd is unusable after it triggered once, create a new one. */
 334         return manager_clock_change_listen(m);
 335 }
 336
 337 static int manager_clock_change_listen(Manager *m) {
 338         int r;
 339
 340         assert(m);
 341
 342         m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
 343
 344         r = event_add_time_change(m->event, &m->clock_change_event_source, on_clock_change, m);
 345         if (r < 0)
 346                 return log_error_errno(r, "Failed to create clock change event source: %m");
 347
 348         return 0;
 349 }
 350
 351 static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 352         _cleanup_free_ char *h = NULL, *n = NULL;
 353         int r;
 354
 355         assert(full_hostname);
 356         assert(llmnr_hostname);
 357         assert(mdns_hostname);
 358
 359         r = resolve_system_hostname(&h, &n);
 360         if (r < 0)
 361                 return r;
 362
 363         r = dns_name_concat(n, "local", 0, mdns_hostname);
 364         if (r < 0)
 365                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 366
 367         *llmnr_hostname = TAKE_PTR(n);
 368         *full_hostname = TAKE_PTR(h);
 369
 370         return 0;
 371 }
 372
 373 static char* fallback_hostname(void) {
 374
 375         /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
 376          * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
 377          * instead. */
 378
 379         _cleanup_free_ char *n = get_default_hostname();
 380         if (!n)
 381                 return NULL;
 382
 383         if (is_localhost(n))
 384                 return strdup("linux");
 385
 386         return TAKE_PTR(n);
 387 }
 388
 389 static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 390         _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
 391         char label[DNS_LABEL_MAX+1];
 392         const char *p;
 393         int r;
 394
 395         assert(full_hostname);
 396         assert(llmnr_hostname);
 397         assert(mdns_hostname);
 398
 399         p = h = fallback_hostname();
 400         if (!h)
 401                 return log_oom();
 402
 403         r = dns_label_unescape(&p, label, sizeof label, 0);
 404         if (r < 0)
 405                 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
 406
 407         assert(r > 0); /* The fallback hostname must have at least one label */
 408
 409         r = dns_label_escape_new(label, r, &n);
 410         if (r < 0)
 411                 return log_error_errno(r, "Failed to escape fallback hostname: %m");
 412
 413         r = dns_name_concat(n, "local", 0, &m);
 414         if (r < 0)
 415                 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
 416
 417         *llmnr_hostname = TAKE_PTR(n);
 418         *mdns_hostname = TAKE_PTR(m);
 419         *full_hostname = TAKE_PTR(h);
 420
 421         return 0;
 422 }
 423
 424 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 425         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 426         Manager *m = ASSERT_PTR(userdata);
 427         bool llmnr_hostname_changed;
 428         int r;
 429
 430         r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
 431         if (r < 0) {
 432                 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
 433                 return 0; /* ignore invalid hostnames */
 434         }
 435
 436         llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
 437         if (streq(full_hostname, m->full_hostname) &&
 438             !llmnr_hostname_changed &&
 439             streq(mdns_hostname, m->mdns_hostname))
 440                 return 0;
 441
 442         log_info("System hostname changed to '%s'.", full_hostname);
 443
 444         free_and_replace(m->full_hostname, full_hostname);
 445         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 446         free_and_replace(m->mdns_hostname, mdns_hostname);
 447
 448         manager_refresh_rrs(m);
 449         (void) manager_send_changed(m, "LLMNRHostname");
 450
 451         return 0;
 452 }
 453
 454 static int manager_watch_hostname(Manager *m) {
 455         int r;
 456
 457         assert(m);
 458
 459         m->hostname_fd = open("/proc/sys/kernel/hostname",
 460                               O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
 461         if (m->hostname_fd < 0) {
 462                 log_warning_errno(errno, "Failed to watch hostname: %m");
 463                 return 0;
 464         }
 465
 466         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 467         if (r < 0) {
 468                 if (r == -EPERM)
 469                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 470                         m->hostname_fd = safe_close(m->hostname_fd);
 471                 else
 472                         return log_error_errno(r, "Failed to add hostname event source: %m");
 473         }
 474
 475         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 476
 477         r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 478         if (r < 0) {
 479                 _cleanup_free_ char *d = NULL;
 480
 481                 d = fallback_hostname();
 482                 if (!d)
 483                         return log_oom();
 484
 485                 log_info("Defaulting to hostname '%s'.", d);
 486
 487                 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 488                 if (r < 0)
 489                         return r;
 490         } else
 491                 log_info("Using system hostname '%s'.", m->full_hostname);
 492
 493         return 0;
 494 }
 495
 496 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 497         _cleanup_(memstream_done) MemStream ms = {};
 498         Manager *m = ASSERT_PTR(userdata);
 499         Link *l;
 500         FILE *f;
 501
 502         assert(s);
 503         assert(si);
 504
 505         f = memstream_init(&ms);
 506         if (!f)
 507                 return log_oom();
 508
 509         LIST_FOREACH(scopes, scope, m->dns_scopes)
 510                 dns_scope_dump(scope, f);
 511
 512         LIST_FOREACH(servers, server, m->dns_servers)
 513                 dns_server_dump(server, f);
 514         LIST_FOREACH(servers, server, m->fallback_dns_servers)
 515                 dns_server_dump(server, f);
 516         HASHMAP_FOREACH(l, m->links)
 517                 LIST_FOREACH(servers, server, l->dns_servers)
 518                         dns_server_dump(server, f);
 519
 520         return memstream_dump(LOG_INFO, &ms);
 521 }
 522
 523 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 524         Manager *m = ASSERT_PTR(userdata);
 525
 526         assert(s);
 527         assert(si);
 528
 529         manager_flush_caches(m, LOG_INFO);
 530
 531         return 0;
 532 }
 533
 534 static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 535         Manager *m = ASSERT_PTR(userdata);
 536
 537         assert(s);
 538         assert(si);
 539
 540         manager_reset_server_features(m);
 541         return 0;
 542 }
 543
 544 static int manager_memory_pressure(sd_event_source *s, void *userdata) {
 545         Manager *m = ASSERT_PTR(userdata);
 546
 547         log_info("Under memory pressure, flushing caches.");
 548
 549         manager_flush_caches(m, LOG_INFO);
 550         sd_event_trim_memory();
 551
 552         return 0;
 553 }
 554
 555 static int manager_memory_pressure_listen(Manager *m) {
 556         int r;
 557
 558         assert(m);
 559
 560         r = sd_event_add_memory_pressure(m->event, NULL, manager_memory_pressure, m);
 561         if (r < 0)
 562                 log_full_errno(ERRNO_IS_NOT_SUPPORTED(r) || ERRNO_IS_PRIVILEGE(r) || (r == -EHOSTDOWN )? LOG_DEBUG : LOG_NOTICE, r,
 563                                "Failed to install memory pressure event source, ignoring: %m");
 564
 565         return 0;
 566 }
 567
 568 int manager_new(Manager **ret) {
 569         _cleanup_(manager_freep) Manager *m = NULL;
 570         int r;
 571
 572         assert(ret);
 573
 574         m = new(Manager, 1);
 575         if (!m)
 576                 return -ENOMEM;
 577
 578         *m = (Manager) {
 579                 .llmnr_ipv4_udp_fd = -EBADF,
 580                 .llmnr_ipv6_udp_fd = -EBADF,
 581                 .llmnr_ipv4_tcp_fd = -EBADF,
 582                 .llmnr_ipv6_tcp_fd = -EBADF,
 583                 .mdns_ipv4_fd = -EBADF,
 584                 .mdns_ipv6_fd = -EBADF,
 585                 .hostname_fd = -EBADF,
 586
 587                 .llmnr_support = DEFAULT_LLMNR_MODE,
 588                 .mdns_support = DEFAULT_MDNS_MODE,
 589                 .dnssec_mode = DEFAULT_DNSSEC_MODE,
 590                 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
 591                 .enable_cache = DNS_CACHE_MODE_YES,
 592                 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
 593                 .read_resolv_conf = true,
 594                 .need_builtin_fallbacks = true,
 595                 .etc_hosts_last = USEC_INFINITY,
 596                 .read_etc_hosts = true,
 597
 598                 .sigrtmin18_info.memory_pressure_handler = manager_memory_pressure,
 599                 .sigrtmin18_info.memory_pressure_userdata = m,
 600         };
 601
 602         r = dns_trust_anchor_load(&m->trust_anchor);
 603         if (r < 0)
 604                 return r;
 605
 606         r = manager_parse_config_file(m);
 607         if (r < 0)
 608                 log_warning_errno(r, "Failed to parse configuration file: %m");
 609
 610 #if ENABLE_DNS_OVER_TLS
 611         r = dnstls_manager_init(m);
 612         if (r < 0)
 613                 return r;
 614 #endif
 615
 616         r = sd_event_default(&m->event);
 617         if (r < 0)
 618                 return r;
 619
 620         (void) sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
 621         (void) sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 622
 623         (void) sd_event_set_watchdog(m->event, true);
 624
 625         r = manager_watch_hostname(m);
 626         if (r < 0)
 627                 return r;
 628
 629         r = dnssd_load(m);
 630         if (r < 0)
 631                 log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
 632
 633         r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
 634         if (r < 0)
 635                 return r;
 636
 637         r = manager_network_monitor_listen(m);
 638         if (r < 0)
 639                 return r;
 640
 641         r = manager_rtnl_listen(m);
 642         if (r < 0)
 643                 return r;
 644
 645         r = manager_clock_change_listen(m);
 646         if (r < 0)
 647                 return r;
 648
 649         r = manager_memory_pressure_listen(m);
 650         if (r < 0)
 651                 return r;
 652
 653         r = manager_connect_bus(m);
 654         if (r < 0)
 655                 return r;
 656
 657         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 658         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 659         (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
 660         (void) sd_event_add_signal(m->event, NULL, SIGRTMIN+18, sigrtmin18_handler, &m->sigrtmin18_info);
 661
 662         manager_cleanup_saved_user(m);
 663
 664         *ret = TAKE_PTR(m);
 665
 666         return 0;
 667 }
 668
 669 int manager_start(Manager *m) {
 670         int r;
 671
 672         assert(m);
 673
 674         r = manager_dns_stub_start(m);
 675         if (r < 0)
 676                 return r;
 677
 678         r = manager_varlink_init(m);
 679         if (r < 0)
 680                 return r;
 681
 682         return 0;
 683 }
 684
 685 Manager *manager_free(Manager *m) {
 686         Link *l;
 687         DnssdService *s;
 688
 689         if (!m)
 690                 return NULL;
 691
 692         dns_server_unlink_all(m->dns_servers);
 693         dns_server_unlink_all(m->fallback_dns_servers);
 694         dns_search_domain_unlink_all(m->search_domains);
 695
 696         while ((l = hashmap_first(m->links)))
 697                link_free(l);
 698
 699         while (m->dns_queries)
 700                 dns_query_free(m->dns_queries);
 701
 702         m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
 703
 704         dns_scope_free(m->unicast_scope);
 705
 706         /* At this point only orphaned streams should remain. All others should have been freed already by their
 707          * owners */
 708         while (m->dns_streams)
 709                 dns_stream_unref(m->dns_streams);
 710
 711 #if ENABLE_DNS_OVER_TLS
 712         dnstls_manager_free(m);
 713 #endif
 714
 715         hashmap_free(m->links);
 716         hashmap_free(m->dns_transactions);
 717
 718         sd_event_source_unref(m->network_event_source);
 719         sd_network_monitor_unref(m->network_monitor);
 720
 721         sd_netlink_unref(m->rtnl);
 722         sd_event_source_unref(m->rtnl_event_source);
 723         sd_event_source_unref(m->clock_change_event_source);
 724
 725         manager_llmnr_stop(m);
 726         manager_mdns_stop(m);
 727         manager_dns_stub_stop(m);
 728         manager_varlink_done(m);
 729
 730         manager_socket_graveyard_clear(m);
 731
 732         ordered_set_free(m->dns_extra_stub_listeners);
 733
 734         hashmap_free(m->polkit_registry);
 735
 736         sd_bus_flush_close_unref(m->bus);
 737
 738         sd_event_source_unref(m->sigusr1_event_source);
 739         sd_event_source_unref(m->sigusr2_event_source);
 740         sd_event_source_unref(m->sigrtmin1_event_source);
 741
 742         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 743         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 744         dns_resource_key_unref(m->mdns_host_ipv4_key);
 745         dns_resource_key_unref(m->mdns_host_ipv6_key);
 746
 747         sd_event_source_unref(m->hostname_event_source);
 748         safe_close(m->hostname_fd);
 749
 750         sd_event_unref(m->event);
 751
 752         free(m->full_hostname);
 753         free(m->llmnr_hostname);
 754         free(m->mdns_hostname);
 755
 756         while ((s = hashmap_first(m->dnssd_services)))
 757                dnssd_service_free(s);
 758         hashmap_free(m->dnssd_services);
 759
 760         dns_trust_anchor_flush(&m->trust_anchor);
 761         manager_etc_hosts_flush(m);
 762
 763         return mfree(m);
 764 }
 765
 766 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 767         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 768         CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 769                          + CMSG_SPACE(int) /* ttl/hoplimit */
 770                          + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
 771         union sockaddr_union sa;
 772         struct iovec iov;
 773         struct msghdr mh = {
 774                 .msg_name = &sa.sa,
 775                 .msg_namelen = sizeof(sa),
 776                 .msg_iov = &iov,
 777                 .msg_iovlen = 1,
 778                 .msg_control = &control,
 779                 .msg_controllen = sizeof(control),
 780         };
 781         struct cmsghdr *cmsg;
 782         ssize_t ms, l;
 783         int r;
 784
 785         assert(m);
 786         assert(fd >= 0);
 787         assert(ret);
 788
 789         ms = next_datagram_size_fd(fd);
 790         if (ms < 0)
 791                 return ms;
 792
 793         r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
 794         if (r < 0)
 795                 return r;
 796
 797         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
 798
 799         l = recvmsg_safe(fd, &mh, 0);
 800         if (ERRNO_IS_NEG_TRANSIENT(l))
 801                 return 0;
 802         if (l <= 0)
 803                 return l;
 804
 805         assert(!(mh.msg_flags & MSG_TRUNC));
 806
 807         p->size = (size_t) l;
 808
 809         p->family = sa.sa.sa_family;
 810         p->ipproto = IPPROTO_UDP;
 811         if (p->family == AF_INET) {
 812                 p->sender.in = sa.in.sin_addr;
 813                 p->sender_port = be16toh(sa.in.sin_port);
 814         } else if (p->family == AF_INET6) {
 815                 p->sender.in6 = sa.in6.sin6_addr;
 816                 p->sender_port = be16toh(sa.in6.sin6_port);
 817                 p->ifindex = sa.in6.sin6_scope_id;
 818         } else
 819                 return -EAFNOSUPPORT;
 820
 821         p->timestamp = now(CLOCK_BOOTTIME);
 822
 823         CMSG_FOREACH(cmsg, &mh) {
 824
 825                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 826                         assert(p->family == AF_INET6);
 827
 828                         switch (cmsg->cmsg_type) {
 829
 830                         case IPV6_PKTINFO: {
 831                                 struct in6_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
 832
 833                                 if (p->ifindex <= 0)
 834                                         p->ifindex = i->ipi6_ifindex;
 835
 836                                 p->destination.in6 = i->ipi6_addr;
 837                                 break;
 838                         }
 839
 840                         case IPV6_HOPLIMIT:
 841                                 p->ttl = *CMSG_TYPED_DATA(cmsg, int);
 842                                 break;
 843
 844                         case IPV6_RECVFRAGSIZE:
 845                                 p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
 846                                 break;
 847                         }
 848                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 849                         assert(p->family == AF_INET);
 850
 851                         switch (cmsg->cmsg_type) {
 852
 853                         case IP_PKTINFO: {
 854                                 struct in_pktinfo *i = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
 855
 856                                 if (p->ifindex <= 0)
 857                                         p->ifindex = i->ipi_ifindex;
 858
 859                                 p->destination.in = i->ipi_addr;
 860                                 break;
 861                         }
 862
 863                         case IP_TTL:
 864                                 p->ttl = *CMSG_TYPED_DATA(cmsg, int);
 865                                 break;
 866
 867                         case IP_RECVFRAGSIZE:
 868                                 p->fragsize = *CMSG_TYPED_DATA(cmsg, int);
 869                                 break;
 870                         }
 871                 }
 872         }
 873
 874         /* The Linux kernel sets the interface index to the loopback
 875          * device if the packet came from the local host since it
 876          * avoids the routing table in such a case. Let's unset the
 877          * interface index in such a case. */
 878         if (p->ifindex == LOOPBACK_IFINDEX)
 879                 p->ifindex = 0;
 880
 881         if (protocol != DNS_PROTOCOL_DNS) {
 882                 /* If we don't know the interface index still, we look for the
 883                  * first local interface with a matching address. Yuck! */
 884                 if (p->ifindex <= 0)
 885                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 886         }
 887
 888         log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%u, fragsize=%zu, sender=%s, destination=%s",
 889                   dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize,
 890                   IN_ADDR_TO_STRING(p->family, &p->sender),
 891                   IN_ADDR_TO_STRING(p->family, &p->destination));
 892
 893         *ret = TAKE_PTR(p);
 894         return 1;
 895 }
 896
 897 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 898         usec_t end;
 899         int r;
 900
 901         assert(fd >= 0);
 902         assert(mh);
 903
 904         end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
 905
 906         for (;;) {
 907                 if (sendmsg(fd, mh, flags) >= 0)
 908                         return 0;
 909                 if (errno == EINTR)
 910                         continue;
 911                 if (errno != EAGAIN)
 912                         return -errno;
 913
 914                 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
 915                 if (ERRNO_IS_NEG_TRANSIENT(r))
 916                         continue;
 917                 if (r < 0)
 918                         return r;
 919                 if (r == 0)
 920                         return -ETIMEDOUT;
 921         }
 922 }
 923
 924 static int write_loop(int fd, void *message, size_t length) {
 925         usec_t end;
 926         int r;
 927
 928         assert(fd >= 0);
 929         assert(message);
 930
 931         end = usec_add(now(CLOCK_MONOTONIC), SEND_TIMEOUT_USEC);
 932
 933         for (;;) {
 934                 if (write(fd, message, length) >= 0)
 935                         return 0;
 936                 if (errno == EINTR)
 937                         continue;
 938                 if (errno != EAGAIN)
 939                         return -errno;
 940
 941                 r = fd_wait_for_event(fd, POLLOUT, LESS_BY(end, now(CLOCK_MONOTONIC)));
 942                 if (ERRNO_IS_NEG_TRANSIENT(r))
 943                         continue;
 944                 if (r < 0)
 945                         return r;
 946                 if (r == 0)
 947                         return -ETIMEDOUT;
 948         }
 949 }
 950
 951 int manager_write(Manager *m, int fd, DnsPacket *p) {
 952         int r;
 953
 954         log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
 955                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
 956                   DNS_PACKET_QR(p) ? "response" : "query",
 957                   DNS_PACKET_ID(p),
 958                   p->size);
 959
 960         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 961         if (r < 0)
 962                 return r;
 963
 964         return 0;
 965 }
 966
 967 static int manager_ipv4_send(
 968                 Manager *m,
 969                 int fd,
 970                 int ifindex,
 971                 const struct in_addr *destination,
 972                 uint16_t port,
 973                 const struct in_addr *source,
 974                 DnsPacket *p) {
 975
 976         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
 977         union sockaddr_union sa;
 978         struct iovec iov;
 979         struct msghdr mh = {
 980                 .msg_iov = &iov,
 981                 .msg_iovlen = 1,
 982                 .msg_name = &sa.sa,
 983                 .msg_namelen = sizeof(sa.in),
 984         };
 985
 986         assert(m);
 987         assert(fd >= 0);
 988         assert(destination);
 989         assert(port > 0);
 990         assert(p);
 991
 992         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
 993
 994         sa = (union sockaddr_union) {
 995                 .in.sin_family = AF_INET,
 996                 .in.sin_addr = *destination,
 997                 .in.sin_port = htobe16(port),
 998         };
 999
1000         if (ifindex > 0) {
1001                 struct cmsghdr *cmsg;
1002                 struct in_pktinfo *pi;
1003
1004                 mh.msg_control = &control;
1005                 mh.msg_controllen = sizeof(control);
1006
1007                 cmsg = CMSG_FIRSTHDR(&mh);
1008                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
1009                 cmsg->cmsg_level = IPPROTO_IP;
1010                 cmsg->cmsg_type = IP_PKTINFO;
1011
1012                 pi = CMSG_TYPED_DATA(cmsg, struct in_pktinfo);
1013                 pi->ipi_ifindex = ifindex;
1014
1015                 if (source)
1016                         pi->ipi_spec_dst = *source;
1017         }
1018
1019         return sendmsg_loop(fd, &mh, 0);
1020 }
1021
1022 static int manager_ipv6_send(
1023                 Manager *m,
1024                 int fd,
1025                 int ifindex,
1026                 const struct in6_addr *destination,
1027                 uint16_t port,
1028                 const struct in6_addr *source,
1029                 DnsPacket *p) {
1030
1031         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1032         union sockaddr_union sa;
1033         struct iovec iov;
1034         struct msghdr mh = {
1035                 .msg_iov = &iov,
1036                 .msg_iovlen = 1,
1037                 .msg_name = &sa.sa,
1038                 .msg_namelen = sizeof(sa.in6),
1039         };
1040
1041         assert(m);
1042         assert(fd >= 0);
1043         assert(destination);
1044         assert(port > 0);
1045         assert(p);
1046
1047         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1048
1049         sa = (union sockaddr_union) {
1050                 .in6.sin6_family = AF_INET6,
1051                 .in6.sin6_addr = *destination,
1052                 .in6.sin6_port = htobe16(port),
1053                 .in6.sin6_scope_id = ifindex,
1054         };
1055
1056         if (ifindex > 0) {
1057                 struct cmsghdr *cmsg;
1058                 struct in6_pktinfo *pi;
1059
1060                 mh.msg_control = &control;
1061                 mh.msg_controllen = sizeof(control);
1062
1063                 cmsg = CMSG_FIRSTHDR(&mh);
1064                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1065                 cmsg->cmsg_level = IPPROTO_IPV6;
1066                 cmsg->cmsg_type = IPV6_PKTINFO;
1067
1068                 pi = CMSG_TYPED_DATA(cmsg, struct in6_pktinfo);
1069                 pi->ipi6_ifindex = ifindex;
1070
1071                 if (source)
1072                         pi->ipi6_addr = *source;
1073         }
1074
1075         return sendmsg_loop(fd, &mh, 0);
1076 }
1077
1078 static int dns_question_to_json(DnsQuestion *q, JsonVariant **ret) {
1079         _cleanup_(json_variant_unrefp) JsonVariant *l = NULL;
1080         DnsResourceKey *key;
1081         int r;
1082
1083         assert(ret);
1084
1085         DNS_QUESTION_FOREACH(key, q) {
1086                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1087
1088                 r = dns_resource_key_to_json(key, &v);
1089                 if (r < 0)
1090                         return r;
1091
1092                 r = json_variant_append_array(&l, v);
1093                 if (r < 0)
1094                         return r;
1095         }
1096
1097         *ret = TAKE_PTR(l);
1098         return 0;
1099 }
1100
1101 int manager_monitor_send(
1102                 Manager *m,
1103                 int state,
1104                 int rcode,
1105                 int error,
1106                 DnsQuestion *question_idna,
1107                 DnsQuestion *question_utf8,
1108                 DnsPacket *question_bypass,
1109                 DnsQuestion *collected_questions,
1110                 DnsAnswer *answer) {
1111
1112         _cleanup_(json_variant_unrefp) JsonVariant *jquestion = NULL, *jcollected_questions = NULL, *janswer = NULL;
1113         _cleanup_(dns_question_unrefp) DnsQuestion *merged = NULL;
1114         Varlink *connection;
1115         DnsAnswerItem *rri;
1116         int r;
1117
1118         assert(m);
1119
1120         if (set_isempty(m->varlink_subscription))
1121                 return 0;
1122
1123         /* Merge all questions into one */
1124         r = dns_question_merge(question_idna, question_utf8, &merged);
1125         if (r < 0)
1126                 return log_error_errno(r, "Failed to merge UTF8/IDNA questions: %m");
1127
1128         if (question_bypass) {
1129                 _cleanup_(dns_question_unrefp) DnsQuestion *merged2 = NULL;
1130
1131                 r = dns_question_merge(merged, question_bypass->question, &merged2);
1132                 if (r < 0)
1133                         return log_error_errno(r, "Failed to merge UTF8/IDNA questions and DNS packet question: %m");
1134
1135                 dns_question_unref(merged);
1136                 merged = TAKE_PTR(merged2);
1137         }
1138
1139         /* Convert the current primary question to JSON */
1140         r = dns_question_to_json(merged, &jquestion);
1141         if (r < 0)
1142                 return log_error_errno(r, "Failed to convert question to JSON: %m");
1143
1144         /* Generate a JSON array of the questions preceding the current one in the CNAME chain */
1145         r = dns_question_to_json(collected_questions, &jcollected_questions);
1146         if (r < 0)
1147                 return log_error_errno(r, "Failed to convert question to JSON: %m");
1148
1149         DNS_ANSWER_FOREACH_ITEM(rri, answer) {
1150                 _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
1151
1152                 r = dns_resource_record_to_json(rri->rr, &v);
1153                 if (r < 0)
1154                         return log_error_errno(r, "Failed to convert answer resource record to JSON: %m");
1155
1156                 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 */
1157                 if (r < 0)
1158                         return log_error_errno(r, "Failed to generate RR wire format: %m");
1159
1160                 r = json_variant_append_arrayb(
1161                                 &janswer,
1162                                 JSON_BUILD_OBJECT(
1163                                                 JSON_BUILD_PAIR_CONDITION(v, "rr", JSON_BUILD_VARIANT(v)),
1164                                                 JSON_BUILD_PAIR("raw", JSON_BUILD_BASE64(rri->rr->wire_format, rri->rr->wire_format_size)),
1165                                                 JSON_BUILD_PAIR_CONDITION(rri->ifindex > 0, "ifindex", JSON_BUILD_INTEGER(rri->ifindex))));
1166                 if (r < 0)
1167                         return log_debug_errno(r, "Failed to append notification entry to array: %m");
1168         }
1169
1170         SET_FOREACH(connection, m->varlink_subscription) {
1171                 r = varlink_notifyb(connection,
1172                                     JSON_BUILD_OBJECT(JSON_BUILD_PAIR("state", JSON_BUILD_STRING(dns_transaction_state_to_string(state))),
1173                                                       JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_RCODE_FAILURE, "rcode", JSON_BUILD_INTEGER(rcode)),
1174                                                       JSON_BUILD_PAIR_CONDITION(state == DNS_TRANSACTION_ERRNO, "errno", JSON_BUILD_INTEGER(error)),
1175                                                       JSON_BUILD_PAIR("question", JSON_BUILD_VARIANT(jquestion)),
1176                                                       JSON_BUILD_PAIR_CONDITION(jcollected_questions, "collectedQuestions", JSON_BUILD_VARIANT(jcollected_questions)),
1177                                                       JSON_BUILD_PAIR_CONDITION(janswer, "answer", JSON_BUILD_VARIANT(janswer))));
1178                 if (r < 0)
1179                         log_debug_errno(r, "Failed to send monitor event, ignoring: %m");
1180         }
1181
1182         return 0;
1183 }
1184
1185 int manager_send(
1186                 Manager *m,
1187                 int fd,
1188                 int ifindex,
1189                 int family,
1190                 const union in_addr_union *destination,
1191                 uint16_t port,
1192                 const union in_addr_union *source,
1193                 DnsPacket *p) {
1194
1195         assert(m);
1196         assert(fd >= 0);
1197         assert(destination);
1198         assert(port > 0);
1199         assert(p);
1200
1201         /* For mDNS, it is natural that the packet have truncated flag when we have many known answers. */
1202         bool truncated = DNS_PACKET_TC(p) && (p->protocol != DNS_PROTOCOL_MDNS || !p->more);
1203
1204         log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1205                   truncated ? "truncated (!) " : "",
1206                   DNS_PACKET_QR(p) ? "response" : "query",
1207                   DNS_PACKET_ID(p),
1208                   ifindex, af_to_name(family),
1209                   p->size);
1210
1211         if (family == AF_INET)
1212                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1213         if (family == AF_INET6)
1214                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1215
1216         return -EAFNOSUPPORT;
1217 }
1218
1219 uint32_t manager_find_mtu(Manager *m) {
1220         uint32_t mtu = 0;
1221         Link *l;
1222
1223         /* If we don't know on which link a DNS packet would be delivered, let's find the largest MTU that
1224          * works on all interfaces we know of that have an IP address associated */
1225
1226         HASHMAP_FOREACH(l, m->links) {
1227                 /* Let's filter out links without IP addresses (e.g. AF_CAN links and suchlike) */
1228                 if (!l->addresses)
1229                         continue;
1230
1231                 /* Safety check: MTU shorter than what we need for the absolutely shortest DNS request? Then
1232                  * let's ignore this link. */
1233                 if (l->mtu < MIN(UDP4_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE,
1234                                  UDP6_PACKET_HEADER_SIZE + DNS_PACKET_HEADER_SIZE))
1235                         continue;
1236
1237                 if (mtu <= 0 || l->mtu < mtu)
1238                         mtu = l->mtu;
1239         }
1240
1241         if (mtu == 0) /* found nothing? then let's assume the typical Ethernet MTU for lack of anything more precise */
1242                 return 1500;
1243
1244         return mtu;
1245 }
1246
1247 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1248         LinkAddress *a;
1249
1250         assert(m);
1251
1252         if (!IN_SET(family, AF_INET, AF_INET6))
1253                 return 0;
1254
1255         if (!in_addr)
1256                 return 0;
1257
1258         a = manager_find_link_address(m, family, in_addr);
1259         if (a)
1260                 return a->link->ifindex;
1261
1262         return 0;
1263 }
1264
1265 void manager_refresh_rrs(Manager *m) {
1266         Link *l;
1267         DnssdService *s;
1268
1269         assert(m);
1270
1271         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1272         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1273         m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1274         m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1275
1276         HASHMAP_FOREACH(l, m->links)
1277                 link_add_rrs(l, true);
1278
1279         if (m->mdns_support == RESOLVE_SUPPORT_YES)
1280                 HASHMAP_FOREACH(s, m->dnssd_services)
1281                         if (dnssd_update_rrs(s) < 0)
1282                                 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1283
1284         HASHMAP_FOREACH(l, m->links)
1285                 link_add_rrs(l, false);
1286 }
1287
1288 static int manager_next_random_name(const char *old, char **ret_new) {
1289         const char *p;
1290         uint64_t u, a;
1291         char *n;
1292
1293         p = strchr(old, 0);
1294         assert(p);
1295
1296         while (p > old) {
1297                 if (!ascii_isdigit(p[-1]))
1298                         break;
1299
1300                 p--;
1301         }
1302
1303         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1304                 u = 1;
1305
1306         /* Add a random number to the old value. This way we can avoid
1307          * that two hosts pick the same hostname, win on IPv4 and lose
1308          * on IPv6 (or vice versa), and pick the same hostname
1309          * replacement hostname, ad infinitum. We still want the
1310          * numbers to go up monotonically, hence we just add a random
1311          * value 1..10 */
1312
1313         random_bytes(&a, sizeof(a));
1314         u += 1 + a % 10;
1315
1316         if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1317                 return -ENOMEM;
1318
1319         *ret_new = n;
1320
1321         return 0;
1322 }
1323
1324 int manager_next_hostname(Manager *m) {
1325         _cleanup_free_ char *h = NULL, *k = NULL;
1326         int r;
1327
1328         assert(m);
1329
1330         r = manager_next_random_name(m->llmnr_hostname, &h);
1331         if (r < 0)
1332                 return r;
1333
1334         r = dns_name_concat(h, "local", 0, &k);
1335         if (r < 0)
1336                 return r;
1337
1338         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1339
1340         free_and_replace(m->llmnr_hostname, h);
1341         free_and_replace(m->mdns_hostname, k);
1342
1343         manager_refresh_rrs(m);
1344         (void) manager_send_changed(m, "LLMNRHostname");
1345
1346         return 0;
1347 }
1348
1349 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1350         Link *l;
1351
1352         assert(m);
1353
1354         if (!IN_SET(family, AF_INET, AF_INET6))
1355                 return NULL;
1356
1357         if (!in_addr)
1358                 return NULL;
1359
1360         HASHMAP_FOREACH(l, m->links) {
1361                 LinkAddress *a;
1362
1363                 a = link_find_address(l, family, in_addr);
1364                 if (a)
1365                         return a;
1366         }
1367
1368         return NULL;
1369 }
1370
1371 bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1372         assert(m);
1373         assert(p);
1374
1375         /* Let's see if this packet comes from an IP address we have on any local interface */
1376
1377         return !!manager_find_link_address(m, p->family, &p->sender);
1378 }
1379
1380 bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1381         DnsTransaction *t;
1382
1383         assert(m);
1384         assert(p);
1385
1386         /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1387          * one we just got. If so, it's almost definitely a packet loop of some kind. */
1388
1389         t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1390         if (!t)
1391                 return false;
1392
1393         return t->sent && dns_packet_equal(t->sent, p);
1394 }
1395
1396 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1397         Link *l;
1398
1399         assert(m);
1400         assert(p);
1401
1402         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1403         if (!l)
1404                 return NULL;
1405
1406         switch (p->protocol) {
1407         case DNS_PROTOCOL_LLMNR:
1408                 if (p->family == AF_INET)
1409                         return l->llmnr_ipv4_scope;
1410                 else if (p->family == AF_INET6)
1411                         return l->llmnr_ipv6_scope;
1412
1413                 break;
1414
1415         case DNS_PROTOCOL_MDNS:
1416                 if (p->family == AF_INET)
1417                         return l->mdns_ipv4_scope;
1418                 else if (p->family == AF_INET6)
1419                         return l->mdns_ipv6_scope;
1420
1421                 break;
1422
1423         default:
1424                 break;
1425         }
1426
1427         return NULL;
1428 }
1429
1430 void manager_verify_all(Manager *m) {
1431         assert(m);
1432
1433         LIST_FOREACH(scopes, s, m->dns_scopes)
1434                 dns_zone_verify_all(&s->zone);
1435 }
1436
1437 int manager_is_own_hostname(Manager *m, const char *name) {
1438         int r;
1439
1440         assert(m);
1441         assert(name);
1442
1443         if (m->llmnr_hostname) {
1444                 r = dns_name_equal(name, m->llmnr_hostname);
1445                 if (r != 0)
1446                         return r;
1447         }
1448
1449         if (m->mdns_hostname) {
1450                 r = dns_name_equal(name, m->mdns_hostname);
1451                 if (r != 0)
1452                         return r;
1453         }
1454
1455         if (m->full_hostname)
1456                 return dns_name_equal(name, m->full_hostname);
1457
1458         return 0;
1459 }
1460
1461 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1462         Link *l;
1463         int r;
1464
1465         assert(m);
1466         assert(dns);
1467
1468         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1469         if (r < 0)
1470                 return r;
1471
1472         /* First add the system-wide servers and domains */
1473         LIST_FOREACH(servers, s, m->dns_servers) {
1474                 r = ordered_set_put(*dns, s);
1475                 if (r == -EEXIST)
1476                         continue;
1477                 if (r < 0)
1478                         return r;
1479         }
1480
1481         /* Then, add the per-link servers */
1482         HASHMAP_FOREACH(l, m->links) {
1483                 LIST_FOREACH(servers, s, l->dns_servers) {
1484                         r = ordered_set_put(*dns, s);
1485                         if (r == -EEXIST)
1486                                 continue;
1487                         if (r < 0)
1488                                 return r;
1489                 }
1490         }
1491
1492         /* If we found nothing, add the fallback servers */
1493         if (ordered_set_isempty(*dns)) {
1494                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1495                         r = ordered_set_put(*dns, s);
1496                         if (r == -EEXIST)
1497                                 continue;
1498                         if (r < 0)
1499                                 return r;
1500                 }
1501         }
1502
1503         return 0;
1504 }
1505
1506 /* filter_route is a tri-state:
1507  *   < 0: no filtering
1508  *   = 0 or false: return only domains which should be used for searching
1509  *   > 0 or true: return only domains which are for routing only
1510  */
1511 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1512         Link *l;
1513         int r;
1514
1515         assert(m);
1516         assert(domains);
1517
1518         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1519         if (r < 0)
1520                 return r;
1521
1522         LIST_FOREACH(domains, d, m->search_domains) {
1523
1524                 if (filter_route >= 0 &&
1525                     d->route_only != !!filter_route)
1526                         continue;
1527
1528                 r = ordered_set_put(*domains, d->name);
1529                 if (r == -EEXIST)
1530                         continue;
1531                 if (r < 0)
1532                         return r;
1533         }
1534
1535         HASHMAP_FOREACH(l, m->links) {
1536
1537                 LIST_FOREACH(domains, d, l->search_domains) {
1538
1539                         if (filter_route >= 0 &&
1540                             d->route_only != !!filter_route)
1541                                 continue;
1542
1543                         r = ordered_set_put(*domains, d->name);
1544                         if (r == -EEXIST)
1545                                 continue;
1546                         if (r < 0)
1547                                 return r;
1548                 }
1549         }
1550
1551         return 0;
1552 }
1553
1554 DnssecMode manager_get_dnssec_mode(Manager *m) {
1555         assert(m);
1556
1557         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1558                 return m->dnssec_mode;
1559
1560         return DNSSEC_NO;
1561 }
1562
1563 bool manager_dnssec_supported(Manager *m) {
1564         DnsServer *server;
1565         Link *l;
1566
1567         assert(m);
1568
1569         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1570                 return false;
1571
1572         server = manager_get_dns_server(m);
1573         if (server && !dns_server_dnssec_supported(server))
1574                 return false;
1575
1576         HASHMAP_FOREACH(l, m->links)
1577                 if (!link_dnssec_supported(l))
1578                         return false;
1579
1580         return true;
1581 }
1582
1583 DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1584         assert(m);
1585
1586         if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1587                 return m->dns_over_tls_mode;
1588
1589         return DNS_OVER_TLS_NO;
1590 }
1591
1592 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1593
1594         assert(verdict >= 0);
1595         assert(verdict < _DNSSEC_VERDICT_MAX);
1596
1597         if (DEBUG_LOGGING) {
1598                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1599
1600                 log_debug("Found verdict for lookup %s: %s",
1601                           dns_resource_key_to_string(key, s, sizeof s),
1602                           dnssec_verdict_to_string(verdict));
1603         }
1604
1605         m->n_dnssec_verdict[verdict]++;
1606 }
1607
1608 bool manager_routable(Manager *m) {
1609         Link *l;
1610
1611         assert(m);
1612
1613         /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1614
1615         HASHMAP_FOREACH(l, m->links)
1616                 if (link_relevant(l, AF_UNSPEC, false))
1617                         return true;
1618
1619         return false;
1620 }
1621
1622 void manager_flush_caches(Manager *m, int log_level) {
1623         assert(m);
1624
1625         LIST_FOREACH(scopes, scope, m->dns_scopes)
1626                 dns_cache_flush(&scope->cache);
1627
1628         log_full(log_level, "Flushed all caches.");
1629 }
1630
1631 void manager_reset_server_features(Manager *m) {
1632         Link *l;
1633
1634         dns_server_reset_features_all(m->dns_servers);
1635         dns_server_reset_features_all(m->fallback_dns_servers);
1636
1637         HASHMAP_FOREACH(l, m->links)
1638                 dns_server_reset_features_all(l->dns_servers);
1639
1640         log_info("Resetting learnt feature levels on all servers.");
1641 }
1642
1643 void manager_cleanup_saved_user(Manager *m) {
1644         _cleanup_closedir_ DIR *d = NULL;
1645
1646         assert(m);
1647
1648         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1649          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1650          * be restarted without losing this data. */
1651
1652         d = opendir("/run/systemd/resolve/netif/");
1653         if (!d) {
1654                 if (errno == ENOENT)
1655                         return;
1656
1657                 log_warning_errno(errno, "Failed to open interface directory: %m");
1658                 return;
1659         }
1660
1661         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1662                 _cleanup_free_ char *p = NULL;
1663                 int ifindex;
1664                 Link *l;
1665
1666                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1667                         continue;
1668
1669                 if (dot_or_dot_dot(de->d_name))
1670                         continue;
1671
1672                 ifindex = parse_ifindex(de->d_name);
1673                 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1674                         goto rm;
1675
1676                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1677                 if (!l) /* link vanished */
1678                         goto rm;
1679
1680                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1681                         goto rm;
1682
1683                 continue;
1684
1685         rm:
1686                 p = path_join("/run/systemd/resolve/netif", de->d_name);
1687                 if (!p) {
1688                         log_oom();
1689                         return;
1690                 }
1691
1692                 (void) unlink(p);
1693         }
1694 }
1695
1696 bool manager_next_dnssd_names(Manager *m) {
1697         DnssdService *s;
1698         bool tried = false;
1699         int r;
1700
1701         assert(m);
1702
1703         HASHMAP_FOREACH(s, m->dnssd_services) {
1704                 _cleanup_free_ char * new_name = NULL;
1705
1706                 if (!s->withdrawn)
1707                         continue;
1708
1709                 r = manager_next_random_name(s->name_template, &new_name);
1710                 if (r < 0) {
1711                         log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1712                         continue;
1713                 }
1714
1715                 free_and_replace(s->name_template, new_name);
1716
1717                 s->withdrawn = false;
1718
1719                 tried = true;
1720         }
1721
1722         if (tried)
1723                 manager_refresh_rrs(m);
1724
1725         return tried;
1726 }
1727
1728 bool manager_server_is_stub(Manager *m, DnsServer *s) {
1729         DnsStubListenerExtra *l;
1730
1731         assert(m);
1732         assert(s);
1733
1734         /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1735          * extra careful, and check here again */
1736         if (s->family == AF_INET &&
1737             s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1738             dns_server_port(s) == 53)
1739                 return true;
1740
1741         /* Main reason to call this is to check server data against the extra listeners, and filter things
1742          * out. */
1743         ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1744                 if (s->family == l->family &&
1745                     in_addr_equal(s->family, &s->address, &l->address) &&
1746                     dns_server_port(s) == dns_stub_listener_extra_port(l))
1747                         return true;
1748
1749         return false;
1750 }
1751
1752 int socket_disable_pmtud(int fd, int af) {
1753         int r;
1754
1755         assert(fd >= 0);
1756
1757         if (af == AF_UNSPEC) {
1758                 af = socket_get_family(fd);
1759                 if (af < 0)
1760                         return af;
1761         }
1762
1763         switch (af) {
1764
1765         case AF_INET: {
1766                 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1767                  * PMTU forgery vulnerabilities.
1768                  *
1769                  * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1770                  * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1771                  * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1772                  * discovery.
1773                  *
1774                  * This helps mitigating the PMTUD vulnerability described here:
1775                  *
1776                  * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1777                  *
1778                  * Similar logic is in place in most DNS servers.
1779                  *
1780                  * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1781                  * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1782                  * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1783                  * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1784                  * fragments seen — and if we need larger packets always go to TCP.
1785                  */
1786
1787                 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1788                 if (r < 0)
1789                         return r;
1790
1791                 return 0;
1792         }
1793
1794         case AF_INET6: {
1795                 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1796                  * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1797                  * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1798                  * because there's nothing that could be fragmented further anymore. */
1799
1800                 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1801                 if (r < 0)
1802                         return r;
1803
1804                 return 0;
1805         }
1806
1807         default:
1808                 return -EAFNOSUPPORT;
1809         }
1810 }
1811
1812 int dns_manager_dump_statistics_json(Manager *m, JsonVariant **ret) {
1813         uint64_t size = 0, hit = 0, miss = 0;
1814
1815         assert(m);
1816         assert(ret);
1817
1818         LIST_FOREACH(scopes, s, m->dns_scopes) {
1819                 size += dns_cache_size(&s->cache);
1820                 hit += s->cache.n_hit;
1821                 miss += s->cache.n_miss;
1822         }
1823
1824         return json_build(ret,
1825                           JSON_BUILD_OBJECT(
1826                                         JSON_BUILD_PAIR("transactions", JSON_BUILD_OBJECT(
1827                                                 JSON_BUILD_PAIR_UNSIGNED("currentTransactions", hashmap_size(m->dns_transactions)),
1828                                                 JSON_BUILD_PAIR_UNSIGNED("totalTransactions", m->n_transactions_total),
1829                                                 JSON_BUILD_PAIR_UNSIGNED("totalTimeouts", m->n_timeouts_total),
1830                                                 JSON_BUILD_PAIR_UNSIGNED("totalTimeoutsServedStale", m->n_timeouts_served_stale_total),
1831                                                 JSON_BUILD_PAIR_UNSIGNED("totalFailedResponses", m->n_failure_responses_total),
1832                                                 JSON_BUILD_PAIR_UNSIGNED("totalFailedResponsesServedStale", m->n_failure_responses_served_stale_total)
1833                                         )),
1834                                         JSON_BUILD_PAIR("cache", JSON_BUILD_OBJECT(
1835                                                 JSON_BUILD_PAIR_UNSIGNED("size", size),
1836                                                 JSON_BUILD_PAIR_UNSIGNED("hits", hit),
1837                                                 JSON_BUILD_PAIR_UNSIGNED("misses", miss)
1838                                         )),
1839                                         JSON_BUILD_PAIR("dnssec", JSON_BUILD_OBJECT(
1840                                                 JSON_BUILD_PAIR_UNSIGNED("secure", m->n_dnssec_verdict[DNSSEC_SECURE]),
1841                                                 JSON_BUILD_PAIR_UNSIGNED("insecure", m->n_dnssec_verdict[DNSSEC_INSECURE]),
1842                                                 JSON_BUILD_PAIR_UNSIGNED("bogus", m->n_dnssec_verdict[DNSSEC_BOGUS]),
1843                                                 JSON_BUILD_PAIR_UNSIGNED("indeterminate", m->n_dnssec_verdict[DNSSEC_INDETERMINATE])
1844                                         ))));
1845 }
1846
1847 void dns_manager_reset_statistics(Manager *m) {
1848
1849         assert(m);
1850
1851         LIST_FOREACH(scopes, s, m->dns_scopes)
1852                 s->cache.n_hit = s->cache.n_miss = 0;
1853
1854         m->n_transactions_total = 0;
1855         m->n_timeouts_total = 0;
1856         m->n_timeouts_served_stale_total = 0;
1857         m->n_failure_responses_total = 0;
1858         m->n_failure_responses_served_stale_total = 0;
1859         zero(m->n_dnssec_verdict);
1860 }