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 "fd-util.h"
  17 #include "fileio.h"
  18 #include "hostname-util.h"
  19 #include "idn-util.h"
  20 #include "io-util.h"
  21 #include "missing_network.h"
  22 #include "missing_socket.h"
  23 #include "netlink-util.h"
  24 #include "ordered-set.h"
  25 #include "parse-util.h"
  26 #include "random-util.h"
  27 #include "resolved-bus.h"
  28 #include "resolved-conf.h"
  29 #include "resolved-dns-stub.h"
  30 #include "resolved-dnssd.h"
  31 #include "resolved-etc-hosts.h"
  32 #include "resolved-llmnr.h"
  33 #include "resolved-manager.h"
  34 #include "resolved-mdns.h"
  35 #include "resolved-resolv-conf.h"
  36 #include "resolved-util.h"
  37 #include "resolved-varlink.h"
  38 #include "socket-util.h"
  39 #include "string-table.h"
  40 #include "string-util.h"
  41 #include "utf8.h"
  42
  43 #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
  44
  45 static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
  46         Manager *m = userdata;
  47         uint16_t type;
  48         Link *l;
  49         int ifindex, r;
  50
  51         assert(rtnl);
  52         assert(m);
  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 = 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         assert(m);
 118
 119         r = sd_netlink_message_get_type(mm, &type);
 120         if (r < 0)
 121                 goto fail;
 122
 123         r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
 124         if (r < 0)
 125                 goto fail;
 126
 127         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
 128         if (!l)
 129                 return 0;
 130
 131         r = sd_rtnl_message_addr_get_family(mm, &family);
 132         if (r < 0)
 133                 goto fail;
 134
 135         switch (family) {
 136
 137         case AF_INET:
 138                 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
 139                 if (r < 0) {
 140                         r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
 141                         if (r < 0)
 142                                 goto fail;
 143                 }
 144
 145                 break;
 146
 147         case AF_INET6:
 148                 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
 149                 if (r < 0) {
 150                         r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
 151                         if (r < 0)
 152                                 goto fail;
 153                 }
 154
 155                 break;
 156
 157         default:
 158                 return 0;
 159         }
 160
 161         a = link_find_address(l, family, &address);
 162
 163         switch (type) {
 164
 165         case RTM_NEWADDR:
 166
 167                 if (!a) {
 168                         r = link_address_new(l, &a, family, &address);
 169                         if (r < 0)
 170                                 return r;
 171                 }
 172
 173                 r = link_address_update_rtnl(a, mm);
 174                 if (r < 0)
 175                         return r;
 176
 177                 break;
 178
 179         case RTM_DELADDR:
 180                 link_address_free(a);
 181                 break;
 182         }
 183
 184         return 0;
 185
 186 fail:
 187         log_warning_errno(r, "Failed to process RTNL address message: %m");
 188         return 0;
 189 }
 190
 191 static int manager_rtnl_listen(Manager *m) {
 192         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 193         sd_netlink_message *i;
 194         int r;
 195
 196         assert(m);
 197
 198         /* First, subscribe to interfaces coming and going */
 199         r = sd_netlink_open(&m->rtnl);
 200         if (r < 0)
 201                 return r;
 202
 203         r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
 204         if (r < 0)
 205                 return r;
 206
 207         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWLINK, manager_process_link, NULL, m, "resolve-NEWLINK");
 208         if (r < 0)
 209                 return r;
 210
 211         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELLINK, manager_process_link, NULL, m, "resolve-DELLINK");
 212         if (r < 0)
 213                 return r;
 214
 215         r = sd_netlink_add_match(m->rtnl, NULL, RTM_NEWADDR, manager_process_address, NULL, m, "resolve-NEWADDR");
 216         if (r < 0)
 217                 return r;
 218
 219         r = sd_netlink_add_match(m->rtnl, NULL, RTM_DELADDR, manager_process_address, NULL, m, "resolve-DELADDR");
 220         if (r < 0)
 221                 return r;
 222
 223         /* Then, enumerate all links */
 224         r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
 225         if (r < 0)
 226                 return r;
 227
 228         r = sd_netlink_message_request_dump(req, true);
 229         if (r < 0)
 230                 return r;
 231
 232         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 233         if (r < 0)
 234                 return r;
 235
 236         for (i = reply; i; i = sd_netlink_message_next(i)) {
 237                 r = manager_process_link(m->rtnl, i, m);
 238                 if (r < 0)
 239                         return r;
 240         }
 241
 242         req = sd_netlink_message_unref(req);
 243         reply = sd_netlink_message_unref(reply);
 244
 245         /* Finally, enumerate all addresses, too */
 246         r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
 247         if (r < 0)
 248                 return r;
 249
 250         r = sd_netlink_message_request_dump(req, true);
 251         if (r < 0)
 252                 return r;
 253
 254         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 255         if (r < 0)
 256                 return r;
 257
 258         for (i = reply; i; i = sd_netlink_message_next(i)) {
 259                 r = manager_process_address(m->rtnl, i, m);
 260                 if (r < 0)
 261                         return r;
 262         }
 263
 264         return r;
 265 }
 266
 267 static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 268         Manager *m = userdata;
 269         Link *l;
 270         int r;
 271
 272         assert(m);
 273
 274         sd_network_monitor_flush(m->network_monitor);
 275
 276         HASHMAP_FOREACH(l, m->links) {
 277                 r = link_update(l);
 278                 if (r < 0)
 279                         log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
 280         }
 281
 282         (void) manager_write_resolv_conf(m);
 283         (void) manager_send_changed(m, "DNS");
 284
 285         return 0;
 286 }
 287
 288 static int manager_network_monitor_listen(Manager *m) {
 289         int r, fd, events;
 290
 291         assert(m);
 292
 293         r = sd_network_monitor_new(&m->network_monitor, NULL);
 294         if (r < 0)
 295                 return r;
 296
 297         fd = sd_network_monitor_get_fd(m->network_monitor);
 298         if (fd < 0)
 299                 return fd;
 300
 301         events = sd_network_monitor_get_events(m->network_monitor);
 302         if (events < 0)
 303                 return events;
 304
 305         r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
 306         if (r < 0)
 307                 return r;
 308
 309         r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
 310         if (r < 0)
 311                 return r;
 312
 313         (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
 314
 315         return 0;
 316 }
 317
 318 static int manager_clock_change_listen(Manager *m);
 319
 320 static int on_clock_change(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
 321         Manager *m = userdata;
 322
 323         assert(m);
 324
 325         /* The clock has changed, let's flush all caches. Why that? That's because DNSSEC validation takes
 326          * the system clock into consideration, and if the clock changes the old validations might have been
 327          * wrong. Let's redo all validation with the new, correct time.
 328          *
 329          * (Also, this is triggered after system suspend, which is also a good reason to drop caches, since
 330          * we might be connected to a different network now without this being visible in a dropped link
 331          * carrier or so.) */
 332
 333         log_info("Clock change detected. Flushing caches.");
 334         manager_flush_caches(m, LOG_DEBUG /* downgrade the functions own log message, since we already logged here at LOG_INFO level */);
 335
 336         /* The clock change timerfd is unusable after it triggered once, create a new one. */
 337         return manager_clock_change_listen(m);
 338 }
 339
 340 static int manager_clock_change_listen(Manager *m) {
 341         _cleanup_close_ int fd = -1;
 342         int r;
 343
 344         assert(m);
 345
 346         m->clock_change_event_source = sd_event_source_disable_unref(m->clock_change_event_source);
 347
 348         fd = time_change_fd();
 349         if (fd < 0)
 350                 return log_error_errno(fd, "Failed to allocate clock change timer fd: %m");
 351
 352         r = sd_event_add_io(m->event, &m->clock_change_event_source, fd, EPOLLIN, on_clock_change, m);
 353         if (r < 0)
 354                 return log_error_errno(r, "Failed to create clock change event source: %m");
 355
 356         r = sd_event_source_set_io_fd_own(m->clock_change_event_source, true);
 357         if (r < 0)
 358                 return log_error_errno(r, "Failed to pass ownership of clock fd to event source: %m");
 359         TAKE_FD(fd);
 360
 361         (void) sd_event_source_set_description(m->clock_change_event_source, "clock-change");
 362
 363         return 0;
 364 }
 365
 366 static int determine_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 367         _cleanup_free_ char *h = NULL, *n = NULL;
 368         int r;
 369
 370         assert(full_hostname);
 371         assert(llmnr_hostname);
 372         assert(mdns_hostname);
 373
 374         r = resolve_system_hostname(&h, &n);
 375         if (r < 0)
 376                 return r;
 377
 378         r = dns_name_concat(n, "local", 0, mdns_hostname);
 379         if (r < 0)
 380                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 381
 382         *llmnr_hostname = TAKE_PTR(n);
 383         *full_hostname = TAKE_PTR(h);
 384
 385         return 0;
 386 }
 387
 388 static char* fallback_hostname(void) {
 389
 390         /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it
 391          * to be "localhost" even if that's the default hostname. In this case, let's revert to "linux"
 392          * instead. */
 393
 394         _cleanup_free_ char *n = get_default_hostname();
 395         if (!n)
 396                 return NULL;
 397
 398         if (is_localhost(n))
 399                 return strdup("linux");
 400
 401         return TAKE_PTR(n);
 402 }
 403
 404 static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 405         _cleanup_free_ char *h = NULL, *n = NULL, *m = NULL;
 406         char label[DNS_LABEL_MAX];
 407         const char *p;
 408         int r;
 409
 410         assert(full_hostname);
 411         assert(llmnr_hostname);
 412         assert(mdns_hostname);
 413
 414         p = h = fallback_hostname();
 415         if (!h)
 416                 return log_oom();
 417
 418         r = dns_label_unescape(&p, label, sizeof label, 0);
 419         if (r < 0)
 420                 return log_error_errno(r, "Failed to unescape fallback hostname: %m");
 421
 422         assert(r > 0); /* The fallback hostname must have at least one label */
 423
 424         r = dns_label_escape_new(label, r, &n);
 425         if (r < 0)
 426                 return log_error_errno(r, "Failed to escape fallback hostname: %m");
 427
 428         r = dns_name_concat(n, "local", 0, &m);
 429         if (r < 0)
 430                 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
 431
 432         *llmnr_hostname = TAKE_PTR(n);
 433         *mdns_hostname = TAKE_PTR(m);
 434         *full_hostname = TAKE_PTR(h);
 435
 436         return 0;
 437 }
 438
 439 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 440         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 441         Manager *m = userdata;
 442         bool llmnr_hostname_changed;
 443         int r;
 444
 445         assert(m);
 446
 447         r = determine_hostnames(&full_hostname, &llmnr_hostname, &mdns_hostname);
 448         if (r < 0) {
 449                 log_warning_errno(r, "Failed to determine the local hostname and LLMNR/mDNS names, ignoring: %m");
 450                 return 0; /* ignore invalid hostnames */
 451         }
 452
 453         llmnr_hostname_changed = !streq(llmnr_hostname, m->llmnr_hostname);
 454         if (streq(full_hostname, m->full_hostname) &&
 455             !llmnr_hostname_changed &&
 456             streq(mdns_hostname, m->mdns_hostname))
 457                 return 0;
 458
 459         log_info("System hostname changed to '%s'.", full_hostname);
 460
 461         free_and_replace(m->full_hostname, full_hostname);
 462         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 463         free_and_replace(m->mdns_hostname, mdns_hostname);
 464
 465         manager_refresh_rrs(m);
 466         (void) manager_send_changed(m, "LLMNRHostname");
 467
 468         return 0;
 469 }
 470
 471 static int manager_watch_hostname(Manager *m) {
 472         int r;
 473
 474         assert(m);
 475
 476         m->hostname_fd = open("/proc/sys/kernel/hostname",
 477                               O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
 478         if (m->hostname_fd < 0) {
 479                 log_warning_errno(errno, "Failed to watch hostname: %m");
 480                 return 0;
 481         }
 482
 483         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 484         if (r < 0) {
 485                 if (r == -EPERM)
 486                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 487                         m->hostname_fd = safe_close(m->hostname_fd);
 488                 else
 489                         return log_error_errno(r, "Failed to add hostname event source: %m");
 490         }
 491
 492         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 493
 494         r = determine_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 495         if (r < 0) {
 496                 _cleanup_free_ char *d = NULL;
 497
 498                 d = fallback_hostname();
 499                 if (!d)
 500                         return log_oom();
 501
 502                 log_info("Defaulting to hostname '%s'.", d);
 503
 504                 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 505                 if (r < 0)
 506                         return r;
 507         } else
 508                 log_info("Using system hostname '%s'.", m->full_hostname);
 509
 510         return 0;
 511 }
 512
 513 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 514         _cleanup_free_ char *buffer = NULL;
 515         _cleanup_fclose_ FILE *f = NULL;
 516         Manager *m = userdata;
 517         DnsServer *server;
 518         size_t size = 0;
 519         DnsScope *scope;
 520         Link *l;
 521
 522         assert(s);
 523         assert(si);
 524         assert(m);
 525
 526         f = open_memstream_unlocked(&buffer, &size);
 527         if (!f)
 528                 return log_oom();
 529
 530         LIST_FOREACH(scopes, scope, m->dns_scopes)
 531                 dns_scope_dump(scope, f);
 532
 533         LIST_FOREACH(servers, server, m->dns_servers)
 534                 dns_server_dump(server, f);
 535         LIST_FOREACH(servers, server, m->fallback_dns_servers)
 536                 dns_server_dump(server, f);
 537         HASHMAP_FOREACH(l, m->links)
 538                 LIST_FOREACH(servers, server, l->dns_servers)
 539                         dns_server_dump(server, f);
 540
 541         if (fflush_and_check(f) < 0)
 542                 return log_oom();
 543
 544         log_dump(LOG_INFO, buffer);
 545         return 0;
 546 }
 547
 548 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 549         Manager *m = userdata;
 550
 551         assert(s);
 552         assert(si);
 553         assert(m);
 554
 555         manager_flush_caches(m, LOG_INFO);
 556
 557         return 0;
 558 }
 559
 560 static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 561         Manager *m = userdata;
 562
 563         assert(s);
 564         assert(si);
 565         assert(m);
 566
 567         manager_reset_server_features(m);
 568         return 0;
 569 }
 570
 571 int manager_new(Manager **ret) {
 572         _cleanup_(manager_freep) Manager *m = NULL;
 573         int r;
 574
 575         assert(ret);
 576
 577         m = new(Manager, 1);
 578         if (!m)
 579                 return -ENOMEM;
 580
 581         *m = (Manager) {
 582                 .llmnr_ipv4_udp_fd = -1,
 583                 .llmnr_ipv6_udp_fd = -1,
 584                 .llmnr_ipv4_tcp_fd = -1,
 585                 .llmnr_ipv6_tcp_fd = -1,
 586                 .mdns_ipv4_fd = -1,
 587                 .mdns_ipv6_fd = -1,
 588                 .hostname_fd = -1,
 589
 590                 .llmnr_support = DEFAULT_LLMNR_MODE,
 591                 .mdns_support = DEFAULT_MDNS_MODE,
 592                 .dnssec_mode = DEFAULT_DNSSEC_MODE,
 593                 .dns_over_tls_mode = DEFAULT_DNS_OVER_TLS_MODE,
 594                 .enable_cache = DNS_CACHE_MODE_YES,
 595                 .dns_stub_listener_mode = DNS_STUB_LISTENER_YES,
 596                 .read_resolv_conf = true,
 597                 .need_builtin_fallbacks = true,
 598                 .etc_hosts_last = USEC_INFINITY,
 599                 .read_etc_hosts = true,
 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_connect_bus(m);
 650         if (r < 0)
 651                 return r;
 652
 653         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 654         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 655         (void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
 656
 657         manager_cleanup_saved_user(m);
 658
 659         *ret = TAKE_PTR(m);
 660
 661         return 0;
 662 }
 663
 664 int manager_start(Manager *m) {
 665         int r;
 666
 667         assert(m);
 668
 669         r = manager_dns_stub_start(m);
 670         if (r < 0)
 671                 return r;
 672
 673         r = manager_varlink_init(m);
 674         if (r < 0)
 675                 return r;
 676
 677         return 0;
 678 }
 679
 680 Manager *manager_free(Manager *m) {
 681         Link *l;
 682         DnssdService *s;
 683
 684         if (!m)
 685                 return NULL;
 686
 687         dns_server_unlink_all(m->dns_servers);
 688         dns_server_unlink_all(m->fallback_dns_servers);
 689         dns_search_domain_unlink_all(m->search_domains);
 690
 691         while ((l = hashmap_first(m->links)))
 692                link_free(l);
 693
 694         while (m->dns_queries)
 695                 dns_query_free(m->dns_queries);
 696
 697         m->stub_queries_by_packet = hashmap_free(m->stub_queries_by_packet);
 698
 699         dns_scope_free(m->unicast_scope);
 700
 701         /* At this point only orphaned streams should remain. All others should have been freed already by their
 702          * owners */
 703         while (m->dns_streams)
 704                 dns_stream_unref(m->dns_streams);
 705
 706 #if ENABLE_DNS_OVER_TLS
 707         dnstls_manager_free(m);
 708 #endif
 709
 710         hashmap_free(m->links);
 711         hashmap_free(m->dns_transactions);
 712
 713         sd_event_source_unref(m->network_event_source);
 714         sd_network_monitor_unref(m->network_monitor);
 715
 716         sd_netlink_unref(m->rtnl);
 717         sd_event_source_unref(m->rtnl_event_source);
 718         sd_event_source_unref(m->clock_change_event_source);
 719
 720         manager_llmnr_stop(m);
 721         manager_mdns_stop(m);
 722         manager_dns_stub_stop(m);
 723         manager_varlink_done(m);
 724
 725         manager_socket_graveyard_clear(m);
 726
 727         ordered_set_free(m->dns_extra_stub_listeners);
 728
 729         bus_verify_polkit_async_registry_free(m->polkit_registry);
 730
 731         sd_bus_flush_close_unref(m->bus);
 732
 733         sd_event_source_unref(m->sigusr1_event_source);
 734         sd_event_source_unref(m->sigusr2_event_source);
 735         sd_event_source_unref(m->sigrtmin1_event_source);
 736
 737         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 738         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 739         dns_resource_key_unref(m->mdns_host_ipv4_key);
 740         dns_resource_key_unref(m->mdns_host_ipv6_key);
 741
 742         sd_event_source_unref(m->hostname_event_source);
 743         safe_close(m->hostname_fd);
 744
 745         sd_event_unref(m->event);
 746
 747         free(m->full_hostname);
 748         free(m->llmnr_hostname);
 749         free(m->mdns_hostname);
 750
 751         while ((s = hashmap_first(m->dnssd_services)))
 752                dnssd_service_free(s);
 753         hashmap_free(m->dnssd_services);
 754
 755         dns_trust_anchor_flush(&m->trust_anchor);
 756         manager_etc_hosts_flush(m);
 757
 758         return mfree(m);
 759 }
 760
 761 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 762         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 763         CMSG_BUFFER_TYPE(CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 764                          + CMSG_SPACE(int) /* ttl/hoplimit */
 765                          + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */) control;
 766         union sockaddr_union sa;
 767         struct iovec iov;
 768         struct msghdr mh = {
 769                 .msg_name = &sa.sa,
 770                 .msg_namelen = sizeof(sa),
 771                 .msg_iov = &iov,
 772                 .msg_iovlen = 1,
 773                 .msg_control = &control,
 774                 .msg_controllen = sizeof(control),
 775         };
 776         struct cmsghdr *cmsg;
 777         ssize_t ms, l;
 778         int r;
 779
 780         assert(m);
 781         assert(fd >= 0);
 782         assert(ret);
 783
 784         ms = next_datagram_size_fd(fd);
 785         if (ms < 0)
 786                 return ms;
 787
 788         r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
 789         if (r < 0)
 790                 return r;
 791
 792         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->allocated);
 793
 794         l = recvmsg_safe(fd, &mh, 0);
 795         if (IN_SET(l, -EAGAIN, -EINTR))
 796                 return 0;
 797         if (l <= 0)
 798                 return l;
 799
 800         assert(!(mh.msg_flags & MSG_TRUNC));
 801
 802         p->size = (size_t) l;
 803
 804         p->family = sa.sa.sa_family;
 805         p->ipproto = IPPROTO_UDP;
 806         if (p->family == AF_INET) {
 807                 p->sender.in = sa.in.sin_addr;
 808                 p->sender_port = be16toh(sa.in.sin_port);
 809         } else if (p->family == AF_INET6) {
 810                 p->sender.in6 = sa.in6.sin6_addr;
 811                 p->sender_port = be16toh(sa.in6.sin6_port);
 812                 p->ifindex = sa.in6.sin6_scope_id;
 813         } else
 814                 return -EAFNOSUPPORT;
 815
 816         p->timestamp = now(clock_boottime_or_monotonic());
 817
 818         CMSG_FOREACH(cmsg, &mh) {
 819
 820                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 821                         assert(p->family == AF_INET6);
 822
 823                         switch (cmsg->cmsg_type) {
 824
 825                         case IPV6_PKTINFO: {
 826                                 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 827
 828                                 if (p->ifindex <= 0)
 829                                         p->ifindex = i->ipi6_ifindex;
 830
 831                                 p->destination.in6 = i->ipi6_addr;
 832                                 break;
 833                         }
 834
 835                         case IPV6_HOPLIMIT:
 836                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 837                                 break;
 838
 839                         case IPV6_RECVFRAGSIZE:
 840                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 841                                 break;
 842                         }
 843                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 844                         assert(p->family == AF_INET);
 845
 846                         switch (cmsg->cmsg_type) {
 847
 848                         case IP_PKTINFO: {
 849                                 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
 850
 851                                 if (p->ifindex <= 0)
 852                                         p->ifindex = i->ipi_ifindex;
 853
 854                                 p->destination.in = i->ipi_addr;
 855                                 break;
 856                         }
 857
 858                         case IP_TTL:
 859                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 860                                 break;
 861
 862                         case IP_RECVFRAGSIZE:
 863                                 p->fragsize = *(int *) CMSG_DATA(cmsg);
 864                                 break;
 865                         }
 866                 }
 867         }
 868
 869         /* The Linux kernel sets the interface index to the loopback
 870          * device if the packet came from the local host since it
 871          * avoids the routing table in such a case. Let's unset the
 872          * interface index in such a case. */
 873         if (p->ifindex == LOOPBACK_IFINDEX)
 874                 p->ifindex = 0;
 875
 876         if (protocol != DNS_PROTOCOL_DNS) {
 877                 /* If we don't know the interface index still, we look for the
 878                  * first local interface with a matching address. Yuck! */
 879                 if (p->ifindex <= 0)
 880                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 881         }
 882
 883         log_debug("Received %s UDP packet of size %zu, ifindex=%i, ttl=%i, fragsize=%zu",
 884                   dns_protocol_to_string(protocol), p->size, p->ifindex, p->ttl, p->fragsize);
 885
 886         *ret = TAKE_PTR(p);
 887         return 1;
 888 }
 889
 890 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 891         int r;
 892
 893         assert(fd >= 0);
 894         assert(mh);
 895
 896         for (;;) {
 897                 if (sendmsg(fd, mh, flags) >= 0)
 898                         return 0;
 899
 900                 if (errno == EINTR)
 901                         continue;
 902
 903                 if (errno != EAGAIN)
 904                         return -errno;
 905
 906                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 907                 if (r < 0)
 908                         return r;
 909                 if (r == 0)
 910                         return -ETIMEDOUT;
 911         }
 912 }
 913
 914 static int write_loop(int fd, void *message, size_t length) {
 915         int r;
 916
 917         assert(fd >= 0);
 918         assert(message);
 919
 920         for (;;) {
 921                 if (write(fd, message, length) >= 0)
 922                         return 0;
 923
 924                 if (errno == EINTR)
 925                         continue;
 926
 927                 if (errno != EAGAIN)
 928                         return -errno;
 929
 930                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 931                 if (r < 0)
 932                         return r;
 933                 if (r == 0)
 934                         return -ETIMEDOUT;
 935         }
 936 }
 937
 938 int manager_write(Manager *m, int fd, DnsPacket *p) {
 939         int r;
 940
 941         log_debug("Sending %s%s packet with id %" PRIu16 " of size %zu.",
 942                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
 943                   DNS_PACKET_QR(p) ? "response" : "query",
 944                   DNS_PACKET_ID(p),
 945                   p->size);
 946
 947         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 948         if (r < 0)
 949                 return r;
 950
 951         return 0;
 952 }
 953
 954 static int manager_ipv4_send(
 955                 Manager *m,
 956                 int fd,
 957                 int ifindex,
 958                 const struct in_addr *destination,
 959                 uint16_t port,
 960                 const struct in_addr *source,
 961                 DnsPacket *p) {
 962
 963         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in_pktinfo))) control = {};
 964         union sockaddr_union sa;
 965         struct iovec iov;
 966         struct msghdr mh = {
 967                 .msg_iov = &iov,
 968                 .msg_iovlen = 1,
 969                 .msg_name = &sa.sa,
 970                 .msg_namelen = sizeof(sa.in),
 971         };
 972
 973         assert(m);
 974         assert(fd >= 0);
 975         assert(destination);
 976         assert(port > 0);
 977         assert(p);
 978
 979         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
 980
 981         sa = (union sockaddr_union) {
 982                 .in.sin_family = AF_INET,
 983                 .in.sin_addr = *destination,
 984                 .in.sin_port = htobe16(port),
 985         };
 986
 987         if (ifindex > 0) {
 988                 struct cmsghdr *cmsg;
 989                 struct in_pktinfo *pi;
 990
 991                 mh.msg_control = &control;
 992                 mh.msg_controllen = sizeof(control);
 993
 994                 cmsg = CMSG_FIRSTHDR(&mh);
 995                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
 996                 cmsg->cmsg_level = IPPROTO_IP;
 997                 cmsg->cmsg_type = IP_PKTINFO;
 998
 999                 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
1000                 pi->ipi_ifindex = ifindex;
1001
1002                 if (source)
1003                         pi->ipi_spec_dst = *source;
1004         }
1005
1006         return sendmsg_loop(fd, &mh, 0);
1007 }
1008
1009 static int manager_ipv6_send(
1010                 Manager *m,
1011                 int fd,
1012                 int ifindex,
1013                 const struct in6_addr *destination,
1014                 uint16_t port,
1015                 const struct in6_addr *source,
1016                 DnsPacket *p) {
1017
1018         CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct in6_pktinfo))) control = {};
1019         union sockaddr_union sa;
1020         struct iovec iov;
1021         struct msghdr mh = {
1022                 .msg_iov = &iov,
1023                 .msg_iovlen = 1,
1024                 .msg_name = &sa.sa,
1025                 .msg_namelen = sizeof(sa.in6),
1026         };
1027
1028         assert(m);
1029         assert(fd >= 0);
1030         assert(destination);
1031         assert(port > 0);
1032         assert(p);
1033
1034         iov = IOVEC_MAKE(DNS_PACKET_DATA(p), p->size);
1035
1036         sa = (union sockaddr_union) {
1037                 .in6.sin6_family = AF_INET6,
1038                 .in6.sin6_addr = *destination,
1039                 .in6.sin6_port = htobe16(port),
1040                 .in6.sin6_scope_id = ifindex,
1041         };
1042
1043         if (ifindex > 0) {
1044                 struct cmsghdr *cmsg;
1045                 struct in6_pktinfo *pi;
1046
1047                 mh.msg_control = &control;
1048                 mh.msg_controllen = sizeof(control);
1049
1050                 cmsg = CMSG_FIRSTHDR(&mh);
1051                 cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
1052                 cmsg->cmsg_level = IPPROTO_IPV6;
1053                 cmsg->cmsg_type = IPV6_PKTINFO;
1054
1055                 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1056                 pi->ipi6_ifindex = ifindex;
1057
1058                 if (source)
1059                         pi->ipi6_addr = *source;
1060         }
1061
1062         return sendmsg_loop(fd, &mh, 0);
1063 }
1064
1065 int manager_send(
1066                 Manager *m,
1067                 int fd,
1068                 int ifindex,
1069                 int family,
1070                 const union in_addr_union *destination,
1071                 uint16_t port,
1072                 const union in_addr_union *source,
1073                 DnsPacket *p) {
1074
1075         assert(m);
1076         assert(fd >= 0);
1077         assert(destination);
1078         assert(port > 0);
1079         assert(p);
1080
1081         log_debug("Sending %s%s packet with id %" PRIu16 " on interface %i/%s of size %zu.",
1082                   DNS_PACKET_TC(p) ? "truncated (!) " : "",
1083                   DNS_PACKET_QR(p) ? "response" : "query",
1084                   DNS_PACKET_ID(p),
1085                   ifindex, af_to_name(family),
1086                   p->size);
1087
1088         if (family == AF_INET)
1089                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, source ? &source->in : NULL, p);
1090         if (family == AF_INET6)
1091                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, source ? &source->in6 : NULL, p);
1092
1093         return -EAFNOSUPPORT;
1094 }
1095
1096 uint32_t manager_find_mtu(Manager *m) {
1097         uint32_t mtu = 0;
1098         Link *l;
1099
1100         /* If we don't know on which link a DNS packet would be
1101          * delivered, let's find the largest MTU that works on all
1102          * interfaces we know of */
1103
1104         HASHMAP_FOREACH(l, m->links) {
1105                 if (l->mtu <= 0)
1106                         continue;
1107
1108                 if (mtu <= 0 || l->mtu < mtu)
1109                         mtu = l->mtu;
1110         }
1111
1112         return mtu;
1113 }
1114
1115 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1116         LinkAddress *a;
1117
1118         assert(m);
1119
1120         if (!IN_SET(family, AF_INET, AF_INET6))
1121                 return 0;
1122
1123         if (!in_addr)
1124                 return 0;
1125
1126         a = manager_find_link_address(m, family, in_addr);
1127         if (a)
1128                 return a->link->ifindex;
1129
1130         return 0;
1131 }
1132
1133 void manager_refresh_rrs(Manager *m) {
1134         Link *l;
1135         DnssdService *s;
1136
1137         assert(m);
1138
1139         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1140         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1141         m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1142         m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1143
1144         if (m->mdns_support == RESOLVE_SUPPORT_YES)
1145                 HASHMAP_FOREACH(s, m->dnssd_services)
1146                         if (dnssd_update_rrs(s) < 0)
1147                                 log_warning("Failed to refresh DNS-SD service '%s'", s->name);
1148
1149         HASHMAP_FOREACH(l, m->links) {
1150                 link_add_rrs(l, true);
1151                 link_add_rrs(l, false);
1152         }
1153 }
1154
1155 static int manager_next_random_name(const char *old, char **ret_new) {
1156         const char *p;
1157         uint64_t u, a;
1158         char *n;
1159
1160         p = strchr(old, 0);
1161         assert(p);
1162
1163         while (p > old) {
1164                 if (!strchr(DIGITS, p[-1]))
1165                         break;
1166
1167                 p--;
1168         }
1169
1170         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1171                 u = 1;
1172
1173         /* Add a random number to the old value. This way we can avoid
1174          * that two hosts pick the same hostname, win on IPv4 and lose
1175          * on IPv6 (or vice versa), and pick the same hostname
1176          * replacement hostname, ad infinitum. We still want the
1177          * numbers to go up monotonically, hence we just add a random
1178          * value 1..10 */
1179
1180         random_bytes(&a, sizeof(a));
1181         u += 1 + a % 10;
1182
1183         if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
1184                 return -ENOMEM;
1185
1186         *ret_new = n;
1187
1188         return 0;
1189 }
1190
1191 int manager_next_hostname(Manager *m) {
1192         _cleanup_free_ char *h = NULL, *k = NULL;
1193         int r;
1194
1195         assert(m);
1196
1197         r = manager_next_random_name(m->llmnr_hostname, &h);
1198         if (r < 0)
1199                 return r;
1200
1201         r = dns_name_concat(h, "local", 0, &k);
1202         if (r < 0)
1203                 return r;
1204
1205         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1206
1207         free_and_replace(m->llmnr_hostname, h);
1208         free_and_replace(m->mdns_hostname, k);
1209
1210         manager_refresh_rrs(m);
1211         (void) manager_send_changed(m, "LLMNRHostname");
1212
1213         return 0;
1214 }
1215
1216 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1217         Link *l;
1218
1219         assert(m);
1220
1221         if (!IN_SET(family, AF_INET, AF_INET6))
1222                 return NULL;
1223
1224         if (!in_addr)
1225                 return NULL;
1226
1227         HASHMAP_FOREACH(l, m->links) {
1228                 LinkAddress *a;
1229
1230                 a = link_find_address(l, family, in_addr);
1231                 if (a)
1232                         return a;
1233         }
1234
1235         return NULL;
1236 }
1237
1238 bool manager_packet_from_local_address(Manager *m, DnsPacket *p) {
1239         assert(m);
1240         assert(p);
1241
1242         /* Let's see if this packet comes from an IP address we have on any local interface */
1243
1244         return !!manager_find_link_address(m, p->family, &p->sender);
1245 }
1246
1247 bool manager_packet_from_our_transaction(Manager *m, DnsPacket *p) {
1248         DnsTransaction *t;
1249
1250         assert(m);
1251         assert(p);
1252
1253         /* Let's see if we have a transaction with a query message with the exact same binary contents as the
1254          * one we just got. If so, it's almost definitely a packet loop of some kind. */
1255
1256         t = hashmap_get(m->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p)));
1257         if (!t)
1258                 return false;
1259
1260         return t->sent && dns_packet_equal(t->sent, p);
1261 }
1262
1263 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1264         Link *l;
1265
1266         assert(m);
1267         assert(p);
1268
1269         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1270         if (!l)
1271                 return NULL;
1272
1273         switch (p->protocol) {
1274         case DNS_PROTOCOL_LLMNR:
1275                 if (p->family == AF_INET)
1276                         return l->llmnr_ipv4_scope;
1277                 else if (p->family == AF_INET6)
1278                         return l->llmnr_ipv6_scope;
1279
1280                 break;
1281
1282         case DNS_PROTOCOL_MDNS:
1283                 if (p->family == AF_INET)
1284                         return l->mdns_ipv4_scope;
1285                 else if (p->family == AF_INET6)
1286                         return l->mdns_ipv6_scope;
1287
1288                 break;
1289
1290         default:
1291                 break;
1292         }
1293
1294         return NULL;
1295 }
1296
1297 void manager_verify_all(Manager *m) {
1298         DnsScope *s;
1299
1300         assert(m);
1301
1302         LIST_FOREACH(scopes, s, m->dns_scopes)
1303                 dns_zone_verify_all(&s->zone);
1304 }
1305
1306 int manager_is_own_hostname(Manager *m, const char *name) {
1307         int r;
1308
1309         assert(m);
1310         assert(name);
1311
1312         if (m->llmnr_hostname) {
1313                 r = dns_name_equal(name, m->llmnr_hostname);
1314                 if (r != 0)
1315                         return r;
1316         }
1317
1318         if (m->mdns_hostname) {
1319                 r = dns_name_equal(name, m->mdns_hostname);
1320                 if (r != 0)
1321                         return r;
1322         }
1323
1324         if (m->full_hostname)
1325                 return dns_name_equal(name, m->full_hostname);
1326
1327         return 0;
1328 }
1329
1330 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1331         DnsServer *s;
1332         Link *l;
1333         int r;
1334
1335         assert(m);
1336         assert(dns);
1337
1338         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1339         if (r < 0)
1340                 return r;
1341
1342         /* First add the system-wide servers and domains */
1343         LIST_FOREACH(servers, s, m->dns_servers) {
1344                 r = ordered_set_put(*dns, s);
1345                 if (r == -EEXIST)
1346                         continue;
1347                 if (r < 0)
1348                         return r;
1349         }
1350
1351         /* Then, add the per-link servers */
1352         HASHMAP_FOREACH(l, m->links) {
1353                 LIST_FOREACH(servers, s, l->dns_servers) {
1354                         r = ordered_set_put(*dns, s);
1355                         if (r == -EEXIST)
1356                                 continue;
1357                         if (r < 0)
1358                                 return r;
1359                 }
1360         }
1361
1362         /* If we found nothing, add the fallback servers */
1363         if (ordered_set_isempty(*dns)) {
1364                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1365                         r = ordered_set_put(*dns, s);
1366                         if (r == -EEXIST)
1367                                 continue;
1368                         if (r < 0)
1369                                 return r;
1370                 }
1371         }
1372
1373         return 0;
1374 }
1375
1376 /* filter_route is a tri-state:
1377  *   < 0: no filtering
1378  *   = 0 or false: return only domains which should be used for searching
1379  *   > 0 or true: return only domains which are for routing only
1380  */
1381 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1382         DnsSearchDomain *d;
1383         Link *l;
1384         int r;
1385
1386         assert(m);
1387         assert(domains);
1388
1389         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1390         if (r < 0)
1391                 return r;
1392
1393         LIST_FOREACH(domains, d, m->search_domains) {
1394
1395                 if (filter_route >= 0 &&
1396                     d->route_only != !!filter_route)
1397                         continue;
1398
1399                 r = ordered_set_put(*domains, d->name);
1400                 if (r == -EEXIST)
1401                         continue;
1402                 if (r < 0)
1403                         return r;
1404         }
1405
1406         HASHMAP_FOREACH(l, m->links) {
1407
1408                 LIST_FOREACH(domains, d, l->search_domains) {
1409
1410                         if (filter_route >= 0 &&
1411                             d->route_only != !!filter_route)
1412                                 continue;
1413
1414                         r = ordered_set_put(*domains, d->name);
1415                         if (r == -EEXIST)
1416                                 continue;
1417                         if (r < 0)
1418                                 return r;
1419                 }
1420         }
1421
1422         return 0;
1423 }
1424
1425 DnssecMode manager_get_dnssec_mode(Manager *m) {
1426         assert(m);
1427
1428         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1429                 return m->dnssec_mode;
1430
1431         return DNSSEC_NO;
1432 }
1433
1434 bool manager_dnssec_supported(Manager *m) {
1435         DnsServer *server;
1436         Link *l;
1437
1438         assert(m);
1439
1440         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1441                 return false;
1442
1443         server = manager_get_dns_server(m);
1444         if (server && !dns_server_dnssec_supported(server))
1445                 return false;
1446
1447         HASHMAP_FOREACH(l, m->links)
1448                 if (!link_dnssec_supported(l))
1449                         return false;
1450
1451         return true;
1452 }
1453
1454 DnsOverTlsMode manager_get_dns_over_tls_mode(Manager *m) {
1455         assert(m);
1456
1457         if (m->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
1458                 return m->dns_over_tls_mode;
1459
1460         return DNS_OVER_TLS_NO;
1461 }
1462
1463 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1464
1465         assert(verdict >= 0);
1466         assert(verdict < _DNSSEC_VERDICT_MAX);
1467
1468         if (DEBUG_LOGGING) {
1469                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1470
1471                 log_debug("Found verdict for lookup %s: %s",
1472                           dns_resource_key_to_string(key, s, sizeof s),
1473                           dnssec_verdict_to_string(verdict));
1474         }
1475
1476         m->n_dnssec_verdict[verdict]++;
1477 }
1478
1479 bool manager_routable(Manager *m) {
1480         Link *l;
1481
1482         assert(m);
1483
1484         /* Returns true if the host has at least one interface with a routable address (regardless if IPv4 or IPv6) */
1485
1486         HASHMAP_FOREACH(l, m->links)
1487                 if (link_relevant(l, AF_UNSPEC, false))
1488                         return true;
1489
1490         return false;
1491 }
1492
1493 void manager_flush_caches(Manager *m, int log_level) {
1494         DnsScope *scope;
1495
1496         assert(m);
1497
1498         LIST_FOREACH(scopes, scope, m->dns_scopes)
1499                 dns_cache_flush(&scope->cache);
1500
1501         log_full(log_level, "Flushed all caches.");
1502 }
1503
1504 void manager_reset_server_features(Manager *m) {
1505         Link *l;
1506
1507         dns_server_reset_features_all(m->dns_servers);
1508         dns_server_reset_features_all(m->fallback_dns_servers);
1509
1510         HASHMAP_FOREACH(l, m->links)
1511                 dns_server_reset_features_all(l->dns_servers);
1512
1513         log_info("Resetting learnt feature levels on all servers.");
1514 }
1515
1516 void manager_cleanup_saved_user(Manager *m) {
1517         _cleanup_closedir_ DIR *d = NULL;
1518         struct dirent *de;
1519
1520         assert(m);
1521
1522         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1523          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1524          * be restarted without losing this data. */
1525
1526         d = opendir("/run/systemd/resolve/netif/");
1527         if (!d) {
1528                 if (errno == ENOENT)
1529                         return;
1530
1531                 log_warning_errno(errno, "Failed to open interface directory: %m");
1532                 return;
1533         }
1534
1535         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1536                 _cleanup_free_ char *p = NULL;
1537                 int ifindex;
1538                 Link *l;
1539
1540                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1541                         continue;
1542
1543                 if (dot_or_dot_dot(de->d_name))
1544                         continue;
1545
1546                 ifindex = parse_ifindex(de->d_name);
1547                 if (ifindex < 0) /* Probably some temporary file from a previous run. Delete it */
1548                         goto rm;
1549
1550                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1551                 if (!l) /* link vanished */
1552                         goto rm;
1553
1554                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1555                         goto rm;
1556
1557                 continue;
1558
1559         rm:
1560                 p = path_join("/run/systemd/resolve/netif", de->d_name);
1561                 if (!p) {
1562                         log_oom();
1563                         return;
1564                 }
1565
1566                 (void) unlink(p);
1567         }
1568 }
1569
1570 bool manager_next_dnssd_names(Manager *m) {
1571         DnssdService *s;
1572         bool tried = false;
1573         int r;
1574
1575         assert(m);
1576
1577         HASHMAP_FOREACH(s, m->dnssd_services) {
1578                 _cleanup_free_ char * new_name = NULL;
1579
1580                 if (!s->withdrawn)
1581                         continue;
1582
1583                 r = manager_next_random_name(s->name_template, &new_name);
1584                 if (r < 0) {
1585                         log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
1586                         continue;
1587                 }
1588
1589                 free_and_replace(s->name_template, new_name);
1590
1591                 s->withdrawn = false;
1592
1593                 tried = true;
1594         }
1595
1596         if (tried)
1597                 manager_refresh_rrs(m);
1598
1599         return tried;
1600 }
1601
1602 bool manager_server_is_stub(Manager *m, DnsServer *s) {
1603         DnsStubListenerExtra *l;
1604
1605         assert(m);
1606         assert(s);
1607
1608         /* Safety check: we generally already skip the main stub when parsing configuration. But let's be
1609          * extra careful, and check here again */
1610         if (s->family == AF_INET &&
1611             s->address.in.s_addr == htobe32(INADDR_DNS_STUB) &&
1612             dns_server_port(s) == 53)
1613                 return true;
1614
1615         /* Main reason to call this is to check server data against the extra listeners, and filter things
1616          * out. */
1617         ORDERED_SET_FOREACH(l, m->dns_extra_stub_listeners)
1618                 if (s->family == l->family &&
1619                     in_addr_equal(s->family, &s->address, &l->address) &&
1620                     dns_server_port(s) == dns_stub_listener_extra_port(l))
1621                         return true;
1622
1623         return false;
1624 }
1625
1626 int socket_disable_pmtud(int fd, int af) {
1627         int r;
1628
1629         assert(fd >= 0);
1630
1631         if (af == AF_UNSPEC) {
1632                 r = socket_get_family(fd, &af);
1633                 if (r < 0)
1634                         return r;
1635         }
1636
1637         switch (af) {
1638
1639         case AF_INET: {
1640                 /* Turn off path MTU discovery, let's rather fragment on the way than to open us up against
1641                  * PMTU forgery vulnerabilities.
1642                  *
1643                  * There appears to be no documentation about IP_PMTUDISC_OMIT, but it has the effect that
1644                  * the "Don't Fragment" bit in the IPv4 header is turned off, thus enforcing fragmentation if
1645                  * our datagram size exceeds the MTU of a router in the path, and turning off path MTU
1646                  * discovery.
1647                  *
1648                  * This helps mitigating the PMTUD vulnerability described here:
1649                  *
1650                  * https://blog.apnic.net/2019/07/12/its-time-to-consider-avoiding-ip-fragmentation-in-the-dns/
1651                  *
1652                  * Similar logic is in place in most DNS servers.
1653                  *
1654                  * There are multiple conflicting goals: we want to allow the largest datagrams possible (for
1655                  * efficiency reasons), but not have fragmentation (for security reasons), nor use PMTUD (for
1656                  * security reasons, too). Our strategy to deal with this is: use large packets, turn off
1657                  * PMTUD, but watch fragmentation taking place, and then size our packets to the max of the
1658                  * fragments seen — and if we need larger packets always go to TCP.
1659                  */
1660
1661                 r = setsockopt_int(fd, IPPROTO_IP, IP_MTU_DISCOVER, IP_PMTUDISC_OMIT);
1662                 if (r < 0)
1663                         return r;
1664
1665                 return 0;
1666         }
1667
1668         case AF_INET6: {
1669                 /* On IPv6 fragmentation only is done by the sender — never by routers on the path. PMTUD is
1670                  * mandatory. If we want to turn off PMTUD, the only way is by sending with minimal MTU only,
1671                  * so that we apply maximum fragmentation locally already, and thus PMTUD doesn't happen
1672                  * because there's nothing that could be fragmented further anymore. */
1673
1674                 r = setsockopt_int(fd, IPPROTO_IPV6, IPV6_MTU, IPV6_MIN_MTU);
1675                 if (r < 0)
1676                         return r;
1677
1678                 return 0;
1679         }
1680
1681         default:
1682                 return -EAFNOSUPPORT;
1683         }
1684 }