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