src/resolve/resolved-manager.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2014 Tom Gundersen <teg@jklm.no>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18  ***/
  19
  20 #include <netinet/in.h>
  21 #include <poll.h>
  22 #include <sys/ioctl.h>
  23
  24 #if HAVE_LIBIDN2
  25 #include <idn2.h>
  26 #endif
  27
  28 #include "af-list.h"
  29 #include "alloc-util.h"
  30 #include "dirent-util.h"
  31 #include "dns-domain.h"
  32 #include "fd-util.h"
  33 #include "fileio-label.h"
  34 #include "hostname-util.h"
  35 #include "io-util.h"
  36 #include "netlink-util.h"
  37 #include "network-internal.h"
  38 #include "ordered-set.h"
  39 #include "parse-util.h"
  40 #include "random-util.h"
  41 #include "resolved-bus.h"
  42 #include "resolved-conf.h"
  43 #include "resolved-dns-stub.h"
  44 #include "resolved-etc-hosts.h"
  45 #include "resolved-llmnr.h"
  46 #include "resolved-manager.h"
  47 #include "resolved-mdns.h"
  48 #include "resolved-resolv-conf.h"
  49 #include "socket-util.h"
  50 #include "string-table.h"
  51 #include "string-util.h"
  52 #include "utf8.h"
  53
  54 #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
  55
  56 static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
  57         Manager *m = userdata;
  58         uint16_t type;
  59         Link *l;
  60         int ifindex, r;
  61
  62         assert(rtnl);
  63         assert(m);
  64         assert(mm);
  65
  66         r = sd_netlink_message_get_type(mm, &type);
  67         if (r < 0)
  68                 goto fail;
  69
  70         r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
  71         if (r < 0)
  72                 goto fail;
  73
  74         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
  75
  76         switch (type) {
  77
  78         case RTM_NEWLINK:{
  79                 bool is_new = !l;
  80
  81                 if (!l) {
  82                         r = link_new(m, &l, ifindex);
  83                         if (r < 0)
  84                                 goto fail;
  85                 }
  86
  87                 r = link_process_rtnl(l, mm);
  88                 if (r < 0)
  89                         goto fail;
  90
  91                 r = link_update(l);
  92                 if (r < 0)
  93                         goto fail;
  94
  95                 if (is_new)
  96                         log_debug("Found new link %i/%s", ifindex, l->name);
  97
  98                 break;
  99         }
 100
 101         case RTM_DELLINK:
 102                 if (l) {
 103                         log_debug("Removing link %i/%s", l->ifindex, l->name);
 104                         link_remove_user(l);
 105                         link_free(l);
 106                 }
 107
 108                 break;
 109         }
 110
 111         return 0;
 112
 113 fail:
 114         log_warning_errno(r, "Failed to process RTNL link message: %m");
 115         return 0;
 116 }
 117
 118 static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
 119         Manager *m = userdata;
 120         union in_addr_union address;
 121         uint16_t type;
 122         int r, ifindex, family;
 123         LinkAddress *a;
 124         Link *l;
 125
 126         assert(rtnl);
 127         assert(mm);
 128         assert(m);
 129
 130         r = sd_netlink_message_get_type(mm, &type);
 131         if (r < 0)
 132                 goto fail;
 133
 134         r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
 135         if (r < 0)
 136                 goto fail;
 137
 138         l = hashmap_get(m->links, INT_TO_PTR(ifindex));
 139         if (!l)
 140                 return 0;
 141
 142         r = sd_rtnl_message_addr_get_family(mm, &family);
 143         if (r < 0)
 144                 goto fail;
 145
 146         switch (family) {
 147
 148         case AF_INET:
 149                 r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
 150                 if (r < 0) {
 151                         r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
 152                         if (r < 0)
 153                                 goto fail;
 154                 }
 155
 156                 break;
 157
 158         case AF_INET6:
 159                 r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
 160                 if (r < 0) {
 161                         r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
 162                         if (r < 0)
 163                                 goto fail;
 164                 }
 165
 166                 break;
 167
 168         default:
 169                 return 0;
 170         }
 171
 172         a = link_find_address(l, family, &address);
 173
 174         switch (type) {
 175
 176         case RTM_NEWADDR:
 177
 178                 if (!a) {
 179                         r = link_address_new(l, &a, family, &address);
 180                         if (r < 0)
 181                                 return r;
 182                 }
 183
 184                 r = link_address_update_rtnl(a, mm);
 185                 if (r < 0)
 186                         return r;
 187
 188                 break;
 189
 190         case RTM_DELADDR:
 191                 link_address_free(a);
 192                 break;
 193         }
 194
 195         return 0;
 196
 197 fail:
 198         log_warning_errno(r, "Failed to process RTNL address message: %m");
 199         return 0;
 200 }
 201
 202 static int manager_rtnl_listen(Manager *m) {
 203         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
 204         sd_netlink_message *i;
 205         int r;
 206
 207         assert(m);
 208
 209         /* First, subscribe to interfaces coming and going */
 210         r = sd_netlink_open(&m->rtnl);
 211         if (r < 0)
 212                 return r;
 213
 214         r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
 215         if (r < 0)
 216                 return r;
 217
 218         r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
 219         if (r < 0)
 220                 return r;
 221
 222         r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
 223         if (r < 0)
 224                 return r;
 225
 226         r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
 227         if (r < 0)
 228                 return r;
 229
 230         r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
 231         if (r < 0)
 232                 return r;
 233
 234         /* Then, enumerate all links */
 235         r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
 236         if (r < 0)
 237                 return r;
 238
 239         r = sd_netlink_message_request_dump(req, true);
 240         if (r < 0)
 241                 return r;
 242
 243         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 244         if (r < 0)
 245                 return r;
 246
 247         for (i = reply; i; i = sd_netlink_message_next(i)) {
 248                 r = manager_process_link(m->rtnl, i, m);
 249                 if (r < 0)
 250                         return r;
 251         }
 252
 253         req = sd_netlink_message_unref(req);
 254         reply = sd_netlink_message_unref(reply);
 255
 256         /* Finally, enumerate all addresses, too */
 257         r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
 258         if (r < 0)
 259                 return r;
 260
 261         r = sd_netlink_message_request_dump(req, true);
 262         if (r < 0)
 263                 return r;
 264
 265         r = sd_netlink_call(m->rtnl, req, 0, &reply);
 266         if (r < 0)
 267                 return r;
 268
 269         for (i = reply; i; i = sd_netlink_message_next(i)) {
 270                 r = manager_process_address(m->rtnl, i, m);
 271                 if (r < 0)
 272                         return r;
 273         }
 274
 275         return r;
 276 }
 277
 278 static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 279         Manager *m = userdata;
 280         Iterator i;
 281         Link *l;
 282         int r;
 283
 284         assert(m);
 285
 286         sd_network_monitor_flush(m->network_monitor);
 287
 288         HASHMAP_FOREACH(l, m->links, i) {
 289                 r = link_update(l);
 290                 if (r < 0)
 291                         log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
 292         }
 293
 294         (void) manager_write_resolv_conf(m);
 295
 296         return 0;
 297 }
 298
 299 static int manager_network_monitor_listen(Manager *m) {
 300         int r, fd, events;
 301
 302         assert(m);
 303
 304         r = sd_network_monitor_new(&m->network_monitor, NULL);
 305         if (r < 0)
 306                 return r;
 307
 308         fd = sd_network_monitor_get_fd(m->network_monitor);
 309         if (fd < 0)
 310                 return fd;
 311
 312         events = sd_network_monitor_get_events(m->network_monitor);
 313         if (events < 0)
 314                 return events;
 315
 316         r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
 317         if (r < 0)
 318                 return r;
 319
 320         r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
 321         if (r < 0)
 322                 return r;
 323
 324         (void) sd_event_source_set_description(m->network_event_source, "network-monitor");
 325
 326         return 0;
 327 }
 328
 329 static int determine_hostname(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 330         _cleanup_free_ char *h = NULL, *n = NULL;
 331 #if HAVE_LIBIDN2
 332         _cleanup_free_ char *utf8 = NULL;
 333 #elif HAVE_LIBIDN
 334         int k;
 335 #endif
 336         char label[DNS_LABEL_MAX];
 337         const char *p, *decoded;
 338         int r;
 339
 340         assert(full_hostname);
 341         assert(llmnr_hostname);
 342         assert(mdns_hostname);
 343
 344         /* Extract and normalize the first label of the locally configured hostname, and check it's not "localhost". */
 345
 346         r = gethostname_strict(&h);
 347         if (r < 0)
 348                 return log_debug_errno(r, "Can't determine system hostname: %m");
 349
 350         p = h;
 351         r = dns_label_unescape(&p, label, sizeof label);
 352         if (r < 0)
 353                 return log_error_errno(r, "Failed to unescape host name: %m");
 354         if (r == 0) {
 355                 log_error("Couldn't find a single label in hostname.");
 356                 return -EINVAL;
 357         }
 358
 359 #if HAVE_LIBIDN2
 360         r = idn2_to_unicode_8z8z(label, &utf8, 0);
 361         if (r != IDN2_OK)
 362                 return log_error("Failed to undo IDNA: %s", idn2_strerror(r));
 363         assert(utf8_is_valid(utf8));
 364
 365         r = strlen(utf8);
 366         decoded = utf8;
 367 #elif HAVE_LIBIDN
 368         k = dns_label_undo_idna(label, r, label, sizeof label);
 369         if (k < 0)
 370                 return log_error_errno(k, "Failed to undo IDNA: %m");
 371         if (k > 0)
 372                 r = k;
 373
 374         if (!utf8_is_valid(label)) {
 375                 log_error("System hostname is not UTF-8 clean.");
 376                 return -EINVAL;
 377         }
 378         decoded = label;
 379 #else
 380         decoded = label; /* no decoding */
 381 #endif
 382
 383         r = dns_label_escape_new(decoded, r, &n);
 384         if (r < 0)
 385                 return log_error_errno(r, "Failed to escape host name: %m");
 386
 387         if (is_localhost(n)) {
 388                 log_debug("System hostname is 'localhost', ignoring.");
 389                 return -EINVAL;
 390         }
 391
 392         r = dns_name_concat(n, "local", mdns_hostname);
 393         if (r < 0)
 394                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 395
 396         *llmnr_hostname = n;
 397         n = NULL;
 398
 399         *full_hostname = h;
 400         h = NULL;
 401
 402         return 0;
 403 }
 404
 405 static const char *fallback_hostname(void) {
 406
 407         /* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it to be
 408          * "localhost" even if that's the compiled in hostname. In this case, let's revert to "linux" instead. */
 409
 410         if (is_localhost(FALLBACK_HOSTNAME))
 411                 return "linux";
 412
 413         return FALLBACK_HOSTNAME;
 414 }
 415
 416 static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
 417         _cleanup_free_ char *n = NULL, *m = NULL;
 418         char label[DNS_LABEL_MAX], *h;
 419         const char *p;
 420         int r;
 421
 422         assert(full_hostname);
 423         assert(llmnr_hostname);
 424         assert(mdns_hostname);
 425
 426         p = fallback_hostname();
 427         r = dns_label_unescape(&p, label, sizeof(label));
 428         if (r < 0)
 429                 return log_error_errno(r, "Failed to unescape fallback host name: %m");
 430
 431         assert(r > 0); /* The fallback hostname must have at least one label */
 432
 433         r = dns_label_escape_new(label, r, &n);
 434         if (r < 0)
 435                 return log_error_errno(r, "Failed to escape fallback hostname: %m");
 436
 437         r = dns_name_concat(n, "local", &m);
 438         if (r < 0)
 439                 return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
 440
 441         h = strdup(fallback_hostname());
 442         if (!h)
 443                 return log_oom();
 444
 445         *llmnr_hostname = n;
 446         n = NULL;
 447
 448         *mdns_hostname = m;
 449         m = NULL;
 450
 451         *full_hostname = h;
 452
 453         return 0;
 454 }
 455
 456 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 457         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 458         Manager *m = userdata;
 459         int r;
 460
 461         assert(m);
 462
 463         r = determine_hostname(&full_hostname, &llmnr_hostname, &mdns_hostname);
 464         if (r < 0)
 465                 return 0; /* ignore invalid hostnames */
 466
 467         if (streq(full_hostname, m->full_hostname) &&
 468             streq(llmnr_hostname, m->llmnr_hostname) &&
 469             streq(mdns_hostname, m->mdns_hostname))
 470                 return 0;
 471
 472         log_info("System hostname changed to '%s'.", full_hostname);
 473
 474         free_and_replace(m->full_hostname, full_hostname);
 475         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 476         free_and_replace(m->mdns_hostname, mdns_hostname);
 477
 478         manager_refresh_rrs(m);
 479
 480         return 0;
 481 }
 482
 483 static int manager_watch_hostname(Manager *m) {
 484         int r;
 485
 486         assert(m);
 487
 488         m->hostname_fd = open("/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC|O_NDELAY|O_NOCTTY);
 489         if (m->hostname_fd < 0) {
 490                 log_warning_errno(errno, "Failed to watch hostname: %m");
 491                 return 0;
 492         }
 493
 494         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 495         if (r < 0) {
 496                 if (r == -EPERM)
 497                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 498                         m->hostname_fd = safe_close(m->hostname_fd);
 499                 else
 500                         return log_error_errno(r, "Failed to add hostname event source: %m");
 501         }
 502
 503         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 504
 505         r = determine_hostname(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 506         if (r < 0) {
 507                 log_info("Defaulting to hostname '%s'.", fallback_hostname());
 508
 509                 r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 510                 if (r < 0)
 511                         return r;
 512         } else
 513                 log_info("Using system hostname '%s'.", m->full_hostname);
 514
 515         return 0;
 516 }
 517
 518 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 519         _cleanup_free_ char *buffer = NULL;
 520         _cleanup_fclose_ FILE *f = NULL;
 521         Manager *m = userdata;
 522         size_t size = 0;
 523         DnsScope *scope;
 524
 525         assert(s);
 526         assert(si);
 527         assert(m);
 528
 529         f = open_memstream(&buffer, &size);
 530         if (!f)
 531                 return log_oom();
 532
 533         LIST_FOREACH(scopes, scope, m->dns_scopes)
 534                 dns_scope_dump(scope, f);
 535
 536         if (fflush_and_check(f) < 0)
 537                 return log_oom();
 538
 539         log_dump(LOG_INFO, buffer);
 540         return 0;
 541 }
 542
 543 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 544         Manager *m = userdata;
 545
 546         assert(s);
 547         assert(si);
 548         assert(m);
 549
 550         manager_flush_caches(m);
 551
 552         return 0;
 553 }
 554
 555 int manager_new(Manager **ret) {
 556         _cleanup_(manager_freep) Manager *m = NULL;
 557         int r;
 558
 559         assert(ret);
 560
 561         m = new0(Manager, 1);
 562         if (!m)
 563                 return -ENOMEM;
 564
 565         m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1;
 566         m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1;
 567         m->mdns_ipv4_fd = m->mdns_ipv6_fd = -1;
 568         m->dns_stub_udp_fd = m->dns_stub_tcp_fd = -1;
 569         m->hostname_fd = -1;
 570
 571         m->llmnr_support = RESOLVE_SUPPORT_YES;
 572         m->mdns_support = RESOLVE_SUPPORT_YES;
 573         m->dnssec_mode = DEFAULT_DNSSEC_MODE;
 574         m->enable_cache = true;
 575         m->dns_stub_listener_mode = DNS_STUB_LISTENER_UDP;
 576         m->read_resolv_conf = true;
 577         m->need_builtin_fallbacks = true;
 578         m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY;
 579
 580         r = dns_trust_anchor_load(&m->trust_anchor);
 581         if (r < 0)
 582                 return r;
 583
 584         r = manager_parse_config_file(m);
 585         if (r < 0)
 586                 log_warning_errno(r, "Failed to parse configuration file: %m");
 587
 588         r = sd_event_default(&m->event);
 589         if (r < 0)
 590                 return r;
 591
 592         sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
 593         sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 594
 595         sd_event_set_watchdog(m->event, true);
 596
 597         r = manager_watch_hostname(m);
 598         if (r < 0)
 599                 return r;
 600
 601         r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
 602         if (r < 0)
 603                 return r;
 604
 605         r = manager_network_monitor_listen(m);
 606         if (r < 0)
 607                 return r;
 608
 609         r = manager_rtnl_listen(m);
 610         if (r < 0)
 611                 return r;
 612
 613         r = manager_connect_bus(m);
 614         if (r < 0)
 615                 return r;
 616
 617         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 618         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 619
 620         manager_cleanup_saved_user(m);
 621
 622         *ret = m;
 623         m = NULL;
 624
 625         return 0;
 626 }
 627
 628 int manager_start(Manager *m) {
 629         int r;
 630
 631         assert(m);
 632
 633         r = manager_dns_stub_start(m);
 634         if (r < 0)
 635                 return r;
 636
 637         return 0;
 638 }
 639
 640 Manager *manager_free(Manager *m) {
 641         Link *l;
 642
 643         if (!m)
 644                 return NULL;
 645
 646         dns_server_unlink_all(m->dns_servers);
 647         dns_server_unlink_all(m->fallback_dns_servers);
 648         dns_search_domain_unlink_all(m->search_domains);
 649
 650         while ((l = hashmap_first(m->links)))
 651                link_free(l);
 652
 653         while (m->dns_queries)
 654                 dns_query_free(m->dns_queries);
 655
 656         dns_scope_free(m->unicast_scope);
 657
 658         /* At this point only orphaned streams should remain. All others should have been freed already by their
 659          * owners */
 660         while (m->dns_streams)
 661                 dns_stream_unref(m->dns_streams);
 662
 663         hashmap_free(m->links);
 664         hashmap_free(m->dns_transactions);
 665
 666         sd_event_source_unref(m->network_event_source);
 667         sd_network_monitor_unref(m->network_monitor);
 668
 669         sd_netlink_unref(m->rtnl);
 670         sd_event_source_unref(m->rtnl_event_source);
 671
 672         manager_llmnr_stop(m);
 673         manager_mdns_stop(m);
 674         manager_dns_stub_stop(m);
 675
 676         sd_bus_slot_unref(m->prepare_for_sleep_slot);
 677         sd_event_source_unref(m->bus_retry_event_source);
 678         sd_bus_unref(m->bus);
 679
 680         sd_event_source_unref(m->sigusr1_event_source);
 681         sd_event_source_unref(m->sigusr2_event_source);
 682
 683         sd_event_unref(m->event);
 684
 685         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 686         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 687         dns_resource_key_unref(m->mdns_host_ipv4_key);
 688         dns_resource_key_unref(m->mdns_host_ipv6_key);
 689
 690         sd_event_source_unref(m->hostname_event_source);
 691         safe_close(m->hostname_fd);
 692
 693         free(m->full_hostname);
 694         free(m->llmnr_hostname);
 695         free(m->mdns_hostname);
 696
 697         dns_trust_anchor_flush(&m->trust_anchor);
 698         manager_etc_hosts_flush(m);
 699
 700         return mfree(m);
 701 }
 702
 703 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 704         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 705         union {
 706                 struct cmsghdr header; /* For alignment */
 707                 uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 708                                + CMSG_SPACE(int) /* ttl/hoplimit */
 709                                + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */];
 710         } control;
 711         union sockaddr_union sa;
 712         struct msghdr mh = {};
 713         struct cmsghdr *cmsg;
 714         struct iovec iov;
 715         ssize_t ms, l;
 716         int r;
 717
 718         assert(m);
 719         assert(fd >= 0);
 720         assert(ret);
 721
 722         ms = next_datagram_size_fd(fd);
 723         if (ms < 0)
 724                 return ms;
 725
 726         r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
 727         if (r < 0)
 728                 return r;
 729
 730         iov.iov_base = DNS_PACKET_DATA(p);
 731         iov.iov_len = p->allocated;
 732
 733         mh.msg_name = &sa.sa;
 734         mh.msg_namelen = sizeof(sa);
 735         mh.msg_iov = &iov;
 736         mh.msg_iovlen = 1;
 737         mh.msg_control = &control;
 738         mh.msg_controllen = sizeof(control);
 739
 740         l = recvmsg(fd, &mh, 0);
 741         if (l == 0)
 742                 return 0;
 743         if (l < 0) {
 744                 if (IN_SET(errno, EAGAIN, EINTR))
 745                         return 0;
 746
 747                 return -errno;
 748         }
 749
 750         assert(!(mh.msg_flags & MSG_CTRUNC));
 751         assert(!(mh.msg_flags & MSG_TRUNC));
 752
 753         p->size = (size_t) l;
 754
 755         p->family = sa.sa.sa_family;
 756         p->ipproto = IPPROTO_UDP;
 757         if (p->family == AF_INET) {
 758                 p->sender.in = sa.in.sin_addr;
 759                 p->sender_port = be16toh(sa.in.sin_port);
 760         } else if (p->family == AF_INET6) {
 761                 p->sender.in6 = sa.in6.sin6_addr;
 762                 p->sender_port = be16toh(sa.in6.sin6_port);
 763                 p->ifindex = sa.in6.sin6_scope_id;
 764         } else
 765                 return -EAFNOSUPPORT;
 766
 767         CMSG_FOREACH(cmsg, &mh) {
 768
 769                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 770                         assert(p->family == AF_INET6);
 771
 772                         switch (cmsg->cmsg_type) {
 773
 774                         case IPV6_PKTINFO: {
 775                                 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 776
 777                                 if (p->ifindex <= 0)
 778                                         p->ifindex = i->ipi6_ifindex;
 779
 780                                 p->destination.in6 = i->ipi6_addr;
 781                                 break;
 782                         }
 783
 784                         case IPV6_HOPLIMIT:
 785                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 786                                 break;
 787
 788                         }
 789                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 790                         assert(p->family == AF_INET);
 791
 792                         switch (cmsg->cmsg_type) {
 793
 794                         case IP_PKTINFO: {
 795                                 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
 796
 797                                 if (p->ifindex <= 0)
 798                                         p->ifindex = i->ipi_ifindex;
 799
 800                                 p->destination.in = i->ipi_addr;
 801                                 break;
 802                         }
 803
 804                         case IP_TTL:
 805                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 806                                 break;
 807                         }
 808                 }
 809         }
 810
 811         /* The Linux kernel sets the interface index to the loopback
 812          * device if the packet came from the local host since it
 813          * avoids the routing table in such a case. Let's unset the
 814          * interface index in such a case. */
 815         if (p->ifindex == LOOPBACK_IFINDEX)
 816                 p->ifindex = 0;
 817
 818         if (protocol != DNS_PROTOCOL_DNS) {
 819                 /* If we don't know the interface index still, we look for the
 820                  * first local interface with a matching address. Yuck! */
 821                 if (p->ifindex <= 0)
 822                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 823         }
 824
 825         *ret = p;
 826         p = NULL;
 827
 828         return 1;
 829 }
 830
 831 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 832         int r;
 833
 834         assert(fd >= 0);
 835         assert(mh);
 836
 837         for (;;) {
 838                 if (sendmsg(fd, mh, flags) >= 0)
 839                         return 0;
 840
 841                 if (errno == EINTR)
 842                         continue;
 843
 844                 if (errno != EAGAIN)
 845                         return -errno;
 846
 847                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 848                 if (r < 0)
 849                         return r;
 850                 if (r == 0)
 851                         return -ETIMEDOUT;
 852         }
 853 }
 854
 855 static int write_loop(int fd, void *message, size_t length) {
 856         int r;
 857
 858         assert(fd >= 0);
 859         assert(message);
 860
 861         for (;;) {
 862                 if (write(fd, message, length) >= 0)
 863                         return 0;
 864
 865                 if (errno == EINTR)
 866                         continue;
 867
 868                 if (errno != EAGAIN)
 869                         return -errno;
 870
 871                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 872                 if (r < 0)
 873                         return r;
 874                 if (r == 0)
 875                         return -ETIMEDOUT;
 876         }
 877 }
 878
 879 int manager_write(Manager *m, int fd, DnsPacket *p) {
 880         int r;
 881
 882         log_debug("Sending %s packet with id %" PRIu16 ".", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p));
 883
 884         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 885         if (r < 0)
 886                 return r;
 887
 888         return 0;
 889 }
 890
 891 static int manager_ipv4_send(
 892                 Manager *m,
 893                 int fd,
 894                 int ifindex,
 895                 const struct in_addr *destination,
 896                 uint16_t port,
 897                 const struct in_addr *source,
 898                 DnsPacket *p) {
 899         union sockaddr_union sa = {
 900                 .in.sin_family = AF_INET,
 901         };
 902         union {
 903                 struct cmsghdr header; /* For alignment */
 904                 uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))];
 905         } control;
 906         struct msghdr mh = {};
 907         struct iovec iov;
 908
 909         assert(m);
 910         assert(fd >= 0);
 911         assert(destination);
 912         assert(port > 0);
 913         assert(p);
 914
 915         iov.iov_base = DNS_PACKET_DATA(p);
 916         iov.iov_len = p->size;
 917
 918         sa.in.sin_addr = *destination;
 919         sa.in.sin_port = htobe16(port),
 920
 921         mh.msg_iov = &iov;
 922         mh.msg_iovlen = 1;
 923         mh.msg_name = &sa.sa;
 924         mh.msg_namelen = sizeof(sa.in);
 925
 926         if (ifindex > 0) {
 927                 struct cmsghdr *cmsg;
 928                 struct in_pktinfo *pi;
 929
 930                 zero(control);
 931
 932                 mh.msg_control = &control;
 933                 mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
 934
 935                 cmsg = CMSG_FIRSTHDR(&mh);
 936                 cmsg->cmsg_len = mh.msg_controllen;
 937                 cmsg->cmsg_level = IPPROTO_IP;
 938                 cmsg->cmsg_type = IP_PKTINFO;
 939
 940                 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
 941                 pi->ipi_ifindex = ifindex;
 942
 943                 if (source)
 944                         pi->ipi_spec_dst = *source;
 945         }
 946
 947         return sendmsg_loop(fd, &mh, 0);
 948 }
 949
 950 static int manager_ipv6_send(
 951                 Manager *m,
 952                 int fd,
 953                 int ifindex,
 954                 const struct in6_addr *destination,
 955                 uint16_t port,
 956                 const struct in6_addr *source,
 957                 DnsPacket *p) {
 958
 959         union sockaddr_union sa = {
 960                 .in6.sin6_family = AF_INET6,
 961         };
 962         union {
 963                 struct cmsghdr header; /* For alignment */
 964                 uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 965         } control;
 966         struct msghdr mh = {};
 967         struct iovec iov;
 968
 969         assert(m);
 970         assert(fd >= 0);
 971         assert(destination);
 972         assert(port > 0);
 973         assert(p);
 974
 975         iov.iov_base = DNS_PACKET_DATA(p);
 976         iov.iov_len = p->size;
 977
 978         sa.in6.sin6_addr = *destination;
 979         sa.in6.sin6_port = htobe16(port),
 980         sa.in6.sin6_scope_id = ifindex;
 981
 982         mh.msg_iov = &iov;
 983         mh.msg_iovlen = 1;
 984         mh.msg_name = &sa.sa;
 985         mh.msg_namelen = sizeof(sa.in6);
 986
 987         if (ifindex > 0) {
 988                 struct cmsghdr *cmsg;
 989                 struct in6_pktinfo *pi;
 990
 991                 zero(control);
 992
 993                 mh.msg_control = &control;
 994                 mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo));
 995
 996                 cmsg = CMSG_FIRSTHDR(&mh);
 997                 cmsg->cmsg_len = mh.msg_controllen;
 998                 cmsg->cmsg_level = IPPROTO_IPV6;
 999                 cmsg->cmsg_type = IPV6_PKTINFO;
1000
1001                 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
1002                 pi->ipi6_ifindex = ifindex;
1003
1004                 if (source)
1005                         pi->ipi6_addr = *source;
1006         }
1007
1008         return sendmsg_loop(fd, &mh, 0);
1009 }
1010
1011 int manager_send(
1012                 Manager *m,
1013                 int fd,
1014                 int ifindex,
1015                 int family,
1016                 const union in_addr_union *destination,
1017                 uint16_t port,
1018                 const union in_addr_union *source,
1019                 DnsPacket *p) {
1020
1021         assert(m);
1022         assert(fd >= 0);
1023         assert(destination);
1024         assert(port > 0);
1025         assert(p);
1026
1027         log_debug("Sending %s packet with id %" PRIu16 " on interface %i/%s.", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family));
1028
1029         if (family == AF_INET)
1030                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, &source->in, p);
1031         if (family == AF_INET6)
1032                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, &source->in6, p);
1033
1034         return -EAFNOSUPPORT;
1035 }
1036
1037 uint32_t manager_find_mtu(Manager *m) {
1038         uint32_t mtu = 0;
1039         Link *l;
1040         Iterator i;
1041
1042         /* If we don't know on which link a DNS packet would be
1043          * delivered, let's find the largest MTU that works on all
1044          * interfaces we know of */
1045
1046         HASHMAP_FOREACH(l, m->links, i) {
1047                 if (l->mtu <= 0)
1048                         continue;
1049
1050                 if (mtu <= 0 || l->mtu < mtu)
1051                         mtu = l->mtu;
1052         }
1053
1054         return mtu;
1055 }
1056
1057 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1058         LinkAddress *a;
1059
1060         assert(m);
1061
1062         a = manager_find_link_address(m, family, in_addr);
1063         if (a)
1064                 return a->link->ifindex;
1065
1066         return 0;
1067 }
1068
1069 void manager_refresh_rrs(Manager *m) {
1070         Iterator i;
1071         Link *l;
1072
1073         assert(m);
1074
1075         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1076         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1077         m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
1078         m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
1079
1080         HASHMAP_FOREACH(l, m->links, i) {
1081                 link_add_rrs(l, true);
1082                 link_add_rrs(l, false);
1083         }
1084 }
1085
1086 int manager_next_hostname(Manager *m) {
1087         const char *p;
1088         uint64_t u, a;
1089         char *h, *k;
1090         int r;
1091
1092         assert(m);
1093
1094         p = strchr(m->llmnr_hostname, 0);
1095         assert(p);
1096
1097         while (p > m->llmnr_hostname) {
1098                 if (!strchr("0123456789", p[-1]))
1099                         break;
1100
1101                 p--;
1102         }
1103
1104         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1105                 u = 1;
1106
1107         /* Add a random number to the old value. This way we can avoid
1108          * that two hosts pick the same hostname, win on IPv4 and lose
1109          * on IPv6 (or vice versa), and pick the same hostname
1110          * replacement hostname, ad infinitum. We still want the
1111          * numbers to go up monotonically, hence we just add a random
1112          * value 1..10 */
1113
1114         random_bytes(&a, sizeof(a));
1115         u += 1 + a % 10;
1116
1117         if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->llmnr_hostname), m->llmnr_hostname, u) < 0)
1118                 return -ENOMEM;
1119
1120         r = dns_name_concat(h, "local", &k);
1121         if (r < 0) {
1122                 free(h);
1123                 return r;
1124         }
1125
1126         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1127
1128         free(m->llmnr_hostname);
1129         m->llmnr_hostname = h;
1130
1131         free(m->mdns_hostname);
1132         m->mdns_hostname = k;
1133
1134         manager_refresh_rrs(m);
1135
1136         return 0;
1137 }
1138
1139 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1140         Iterator i;
1141         Link *l;
1142
1143         assert(m);
1144
1145         HASHMAP_FOREACH(l, m->links, i) {
1146                 LinkAddress *a;
1147
1148                 a = link_find_address(l, family, in_addr);
1149                 if (a)
1150                         return a;
1151         }
1152
1153         return NULL;
1154 }
1155
1156 bool manager_our_packet(Manager *m, DnsPacket *p) {
1157         assert(m);
1158         assert(p);
1159
1160         return !!manager_find_link_address(m, p->family, &p->sender);
1161 }
1162
1163 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1164         Link *l;
1165
1166         assert(m);
1167         assert(p);
1168
1169         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1170         if (!l)
1171                 return NULL;
1172
1173         switch (p->protocol) {
1174         case DNS_PROTOCOL_LLMNR:
1175                 if (p->family == AF_INET)
1176                         return l->llmnr_ipv4_scope;
1177                 else if (p->family == AF_INET6)
1178                         return l->llmnr_ipv6_scope;
1179
1180                 break;
1181
1182         case DNS_PROTOCOL_MDNS:
1183                 if (p->family == AF_INET)
1184                         return l->mdns_ipv4_scope;
1185                 else if (p->family == AF_INET6)
1186                         return l->mdns_ipv6_scope;
1187
1188                 break;
1189
1190         default:
1191                 break;
1192         }
1193
1194         return NULL;
1195 }
1196
1197 void manager_verify_all(Manager *m) {
1198         DnsScope *s;
1199
1200         assert(m);
1201
1202         LIST_FOREACH(scopes, s, m->dns_scopes)
1203                 dns_zone_verify_all(&s->zone);
1204 }
1205
1206 int manager_is_own_hostname(Manager *m, const char *name) {
1207         int r;
1208
1209         assert(m);
1210         assert(name);
1211
1212         if (m->llmnr_hostname) {
1213                 r = dns_name_equal(name, m->llmnr_hostname);
1214                 if (r != 0)
1215                         return r;
1216         }
1217
1218         if (m->mdns_hostname) {
1219                 r = dns_name_equal(name, m->mdns_hostname);
1220                 if (r != 0)
1221                         return r;
1222         }
1223
1224         if (m->full_hostname)
1225                 return dns_name_equal(name, m->full_hostname);
1226
1227         return 0;
1228 }
1229
1230 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1231         DnsServer *s;
1232         Iterator i;
1233         Link *l;
1234         int r;
1235
1236         assert(m);
1237         assert(dns);
1238
1239         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1240         if (r < 0)
1241                 return r;
1242
1243         /* First add the system-wide servers and domains */
1244         LIST_FOREACH(servers, s, m->dns_servers) {
1245                 r = ordered_set_put(*dns, s);
1246                 if (r == -EEXIST)
1247                         continue;
1248                 if (r < 0)
1249                         return r;
1250         }
1251
1252         /* Then, add the per-link servers */
1253         HASHMAP_FOREACH(l, m->links, i) {
1254                 LIST_FOREACH(servers, s, l->dns_servers) {
1255                         r = ordered_set_put(*dns, s);
1256                         if (r == -EEXIST)
1257                                 continue;
1258                         if (r < 0)
1259                                 return r;
1260                 }
1261         }
1262
1263         /* If we found nothing, add the fallback servers */
1264         if (ordered_set_isempty(*dns)) {
1265                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1266                         r = ordered_set_put(*dns, s);
1267                         if (r == -EEXIST)
1268                                 continue;
1269                         if (r < 0)
1270                                 return r;
1271                 }
1272         }
1273
1274         return 0;
1275 }
1276
1277 /* filter_route is a tri-state:
1278  *   < 0: no filtering
1279  *   = 0 or false: return only domains which should be used for searching
1280  *   > 0 or true: return only domains which are for routing only
1281  */
1282 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1283         DnsSearchDomain *d;
1284         Iterator i;
1285         Link *l;
1286         int r;
1287
1288         assert(m);
1289         assert(domains);
1290
1291         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1292         if (r < 0)
1293                 return r;
1294
1295         LIST_FOREACH(domains, d, m->search_domains) {
1296
1297                 if (filter_route >= 0 &&
1298                     d->route_only != !!filter_route)
1299                         continue;
1300
1301                 r = ordered_set_put(*domains, d->name);
1302                 if (r == -EEXIST)
1303                         continue;
1304                 if (r < 0)
1305                         return r;
1306         }
1307
1308         HASHMAP_FOREACH(l, m->links, i) {
1309
1310                 LIST_FOREACH(domains, d, l->search_domains) {
1311
1312                         if (filter_route >= 0 &&
1313                             d->route_only != !!filter_route)
1314                                 continue;
1315
1316                         r = ordered_set_put(*domains, d->name);
1317                         if (r == -EEXIST)
1318                                 continue;
1319                         if (r < 0)
1320                                 return r;
1321                 }
1322         }
1323
1324         return 0;
1325 }
1326
1327 DnssecMode manager_get_dnssec_mode(Manager *m) {
1328         assert(m);
1329
1330         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1331                 return m->dnssec_mode;
1332
1333         return DNSSEC_NO;
1334 }
1335
1336 bool manager_dnssec_supported(Manager *m) {
1337         DnsServer *server;
1338         Iterator i;
1339         Link *l;
1340
1341         assert(m);
1342
1343         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1344                 return false;
1345
1346         server = manager_get_dns_server(m);
1347         if (server && !dns_server_dnssec_supported(server))
1348                 return false;
1349
1350         HASHMAP_FOREACH(l, m->links, i)
1351                 if (!link_dnssec_supported(l))
1352                         return false;
1353
1354         return true;
1355 }
1356
1357 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1358
1359         assert(verdict >= 0);
1360         assert(verdict < _DNSSEC_VERDICT_MAX);
1361
1362         if (log_get_max_level() >= LOG_DEBUG) {
1363                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1364
1365                 log_debug("Found verdict for lookup %s: %s",
1366                           dns_resource_key_to_string(key, s, sizeof s),
1367                           dnssec_verdict_to_string(verdict));
1368         }
1369
1370         m->n_dnssec_verdict[verdict]++;
1371 }
1372
1373 bool manager_routable(Manager *m, int family) {
1374         Iterator i;
1375         Link *l;
1376
1377         assert(m);
1378
1379         /* Returns true if the host has at least one interface with a routable address of the specified type */
1380
1381         HASHMAP_FOREACH(l, m->links, i)
1382                 if (link_relevant(l, family, false))
1383                         return true;
1384
1385         return false;
1386 }
1387
1388 void manager_flush_caches(Manager *m) {
1389         DnsScope *scope;
1390
1391         assert(m);
1392
1393         LIST_FOREACH(scopes, scope, m->dns_scopes)
1394                 dns_cache_flush(&scope->cache);
1395
1396         log_info("Flushed all caches.");
1397 }
1398
1399 void manager_reset_server_features(Manager *m) {
1400         Iterator i;
1401         Link *l;
1402
1403         dns_server_reset_features_all(m->dns_servers);
1404         dns_server_reset_features_all(m->fallback_dns_servers);
1405
1406         HASHMAP_FOREACH(l, m->links, i)
1407                 dns_server_reset_features_all(l->dns_servers);
1408
1409         log_info("Resetting learnt feature levels on all servers.");
1410 }
1411
1412 void manager_cleanup_saved_user(Manager *m) {
1413         _cleanup_closedir_ DIR *d = NULL;
1414         struct dirent *de;
1415         int r;
1416
1417         assert(m);
1418
1419         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1420          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1421          * be restarted without losing this data. */
1422
1423         d = opendir("/run/systemd/resolve/netif/");
1424         if (!d) {
1425                 if (errno == ENOENT)
1426                         return;
1427
1428                 log_warning_errno(errno, "Failed to open interface directory: %m");
1429                 return;
1430         }
1431
1432         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1433                 _cleanup_free_ char *p = NULL;
1434                 int ifindex;
1435                 Link *l;
1436
1437                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1438                         continue;
1439
1440                 if (dot_or_dot_dot(de->d_name))
1441                         continue;
1442
1443                 r = parse_ifindex(de->d_name, &ifindex);
1444                 if (r < 0) /* Probably some temporary file from a previous run. Delete it */
1445                         goto rm;
1446
1447                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1448                 if (!l) /* link vanished */
1449                         goto rm;
1450
1451                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1452                         goto rm;
1453
1454                 continue;
1455
1456         rm:
1457                 p = strappend("/run/systemd/resolve/netif/", de->d_name);
1458                 if (!p) {
1459                         log_oom();
1460                         return;
1461                 }
1462
1463                 (void) unlink(p);
1464         }
1465 }