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
 336          * configured hostname, and check it's not "localhost". */
 337
 338         h = gethostname_malloc();
 339         if (!h)
 340                 return log_oom();
 341
 342         p = h;
 343         r = dns_label_unescape(&p, label, sizeof(label));
 344         if (r < 0)
 345                 return log_error_errno(r, "Failed to unescape host name: %m");
 346         if (r == 0) {
 347                 log_error("Couldn't find a single label in hosntame.");
 348                 return -EINVAL;
 349         }
 350
 351         k = dns_label_undo_idna(label, r, label, sizeof(label));
 352         if (k < 0)
 353                 return log_error_errno(k, "Failed to undo IDNA: %m");
 354         if (k > 0)
 355                 r = k;
 356
 357         if (!utf8_is_valid(label)) {
 358                 log_error("System hostname is not UTF-8 clean.");
 359                 return -EINVAL;
 360         }
 361
 362         r = dns_label_escape_new(label, r, &n);
 363         if (r < 0)
 364                 return log_error_errno(r, "Failed to escape host name: %m");
 365
 366         if (is_localhost(n)) {
 367                 log_debug("System hostname is 'localhost', ignoring.");
 368                 return -EINVAL;
 369         }
 370
 371         r = dns_name_concat(n, "local", mdns_hostname);
 372         if (r < 0)
 373                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 374
 375         *llmnr_hostname = n;
 376         n = NULL;
 377
 378         *full_hostname = h;
 379         h = NULL;
 380
 381         return 0;
 382 }
 383
 384 static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 385         _cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
 386         Manager *m = userdata;
 387         int r;
 388
 389         assert(m);
 390
 391         r = determine_hostname(&full_hostname, &llmnr_hostname, &mdns_hostname);
 392         if (r < 0)
 393                 return 0; /* ignore invalid hostnames */
 394
 395         if (streq(full_hostname, m->full_hostname) &&
 396             streq(llmnr_hostname, m->llmnr_hostname) &&
 397             streq(mdns_hostname, m->mdns_hostname))
 398                 return 0;
 399
 400         log_info("System hostname changed to '%s'.", full_hostname);
 401
 402         free_and_replace(m->full_hostname, full_hostname);
 403         free_and_replace(m->llmnr_hostname, llmnr_hostname);
 404         free_and_replace(m->mdns_hostname, mdns_hostname);
 405
 406         manager_refresh_rrs(m);
 407
 408         return 0;
 409 }
 410
 411 static int manager_watch_hostname(Manager *m) {
 412         int r;
 413
 414         assert(m);
 415
 416         m->hostname_fd = open("/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC|O_NDELAY|O_NOCTTY);
 417         if (m->hostname_fd < 0) {
 418                 log_warning_errno(errno, "Failed to watch hostname: %m");
 419                 return 0;
 420         }
 421
 422         r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
 423         if (r < 0) {
 424                 if (r == -EPERM)
 425                         /* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
 426                         m->hostname_fd = safe_close(m->hostname_fd);
 427                 else
 428                         return log_error_errno(r, "Failed to add hostname event source: %m");
 429         }
 430
 431         (void) sd_event_source_set_description(m->hostname_event_source, "hostname");
 432
 433         r = determine_hostname(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
 434         if (r < 0) {
 435                 log_info("Defaulting to hostname 'linux'.");
 436
 437                 m->full_hostname = strdup("linux");
 438                 if (!m->full_hostname)
 439                         return log_oom();
 440
 441                 m->llmnr_hostname = strdup("linux");
 442                 if (!m->llmnr_hostname)
 443                         return log_oom();
 444
 445                 m->mdns_hostname = strdup("linux.local");
 446                 if (!m->mdns_hostname)
 447                         return log_oom();
 448         } else
 449                 log_info("Using system hostname '%s'.", m->full_hostname);
 450
 451         return 0;
 452 }
 453
 454 static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 455         _cleanup_free_ char *buffer = NULL;
 456         _cleanup_fclose_ FILE *f = NULL;
 457         Manager *m = userdata;
 458         size_t size = 0;
 459         DnsScope *scope;
 460
 461         assert(s);
 462         assert(si);
 463         assert(m);
 464
 465         f = open_memstream(&buffer, &size);
 466         if (!f)
 467                 return log_oom();
 468
 469         LIST_FOREACH(scopes, scope, m->dns_scopes)
 470                 dns_scope_dump(scope, f);
 471
 472         if (fflush_and_check(f) < 0)
 473                 return log_oom();
 474
 475         log_dump(LOG_INFO, buffer);
 476         return 0;
 477 }
 478
 479 static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 480         Manager *m = userdata;
 481
 482         assert(s);
 483         assert(si);
 484         assert(m);
 485
 486         manager_flush_caches(m);
 487
 488         return 0;
 489 }
 490
 491 int manager_new(Manager **ret) {
 492         _cleanup_(manager_freep) Manager *m = NULL;
 493         int r;
 494
 495         assert(ret);
 496
 497         m = new0(Manager, 1);
 498         if (!m)
 499                 return -ENOMEM;
 500
 501         m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1;
 502         m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1;
 503         m->mdns_ipv4_fd = m->mdns_ipv6_fd = -1;
 504         m->dns_stub_udp_fd = m->dns_stub_tcp_fd = -1;
 505         m->hostname_fd = -1;
 506
 507         m->llmnr_support = RESOLVE_SUPPORT_YES;
 508         m->mdns_support = RESOLVE_SUPPORT_NO;
 509         m->dnssec_mode = DEFAULT_DNSSEC_MODE;
 510         m->enable_cache = true;
 511         m->dns_stub_listener_mode = DNS_STUB_LISTENER_UDP;
 512         m->read_resolv_conf = true;
 513         m->need_builtin_fallbacks = true;
 514         m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY;
 515
 516         r = dns_trust_anchor_load(&m->trust_anchor);
 517         if (r < 0)
 518                 return r;
 519
 520         r = manager_parse_config_file(m);
 521         if (r < 0)
 522                 return r;
 523
 524         r = sd_event_default(&m->event);
 525         if (r < 0)
 526                 return r;
 527
 528         sd_event_add_signal(m->event, NULL, SIGTERM, NULL,  NULL);
 529         sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
 530
 531         sd_event_set_watchdog(m->event, true);
 532
 533         r = manager_watch_hostname(m);
 534         if (r < 0)
 535                 return r;
 536
 537         r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
 538         if (r < 0)
 539                 return r;
 540
 541         r = manager_network_monitor_listen(m);
 542         if (r < 0)
 543                 return r;
 544
 545         r = manager_rtnl_listen(m);
 546         if (r < 0)
 547                 return r;
 548
 549         r = manager_connect_bus(m);
 550         if (r < 0)
 551                 return r;
 552
 553         (void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
 554         (void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
 555
 556         manager_cleanup_saved_user(m);
 557
 558         *ret = m;
 559         m = NULL;
 560
 561         return 0;
 562 }
 563
 564 int manager_start(Manager *m) {
 565         int r;
 566
 567         assert(m);
 568
 569         r = manager_dns_stub_start(m);
 570         if (r < 0)
 571                 return r;
 572
 573         r = manager_llmnr_start(m);
 574         if (r < 0)
 575                 return r;
 576
 577         r = manager_mdns_start(m);
 578         if (r < 0)
 579                 return r;
 580
 581         return 0;
 582 }
 583
 584 Manager *manager_free(Manager *m) {
 585         Link *l;
 586
 587         if (!m)
 588                 return NULL;
 589
 590         dns_server_unlink_all(m->dns_servers);
 591         dns_server_unlink_all(m->fallback_dns_servers);
 592         dns_search_domain_unlink_all(m->search_domains);
 593
 594         while ((l = hashmap_first(m->links)))
 595                link_free(l);
 596
 597         while (m->dns_queries)
 598                 dns_query_free(m->dns_queries);
 599
 600         dns_scope_free(m->unicast_scope);
 601
 602         /* At this point only orphaned streams should remain. All others should have been freed already by their
 603          * owners */
 604         while (m->dns_streams)
 605                 dns_stream_unref(m->dns_streams);
 606
 607         hashmap_free(m->links);
 608         hashmap_free(m->dns_transactions);
 609
 610         sd_event_source_unref(m->network_event_source);
 611         sd_network_monitor_unref(m->network_monitor);
 612
 613         sd_netlink_unref(m->rtnl);
 614         sd_event_source_unref(m->rtnl_event_source);
 615
 616         manager_llmnr_stop(m);
 617         manager_mdns_stop(m);
 618         manager_dns_stub_stop(m);
 619
 620         sd_bus_slot_unref(m->prepare_for_sleep_slot);
 621         sd_event_source_unref(m->bus_retry_event_source);
 622         sd_bus_unref(m->bus);
 623
 624         sd_event_source_unref(m->sigusr1_event_source);
 625         sd_event_source_unref(m->sigusr2_event_source);
 626
 627         sd_event_unref(m->event);
 628
 629         dns_resource_key_unref(m->llmnr_host_ipv4_key);
 630         dns_resource_key_unref(m->llmnr_host_ipv6_key);
 631
 632         sd_event_source_unref(m->hostname_event_source);
 633         safe_close(m->hostname_fd);
 634
 635         free(m->full_hostname);
 636         free(m->llmnr_hostname);
 637         free(m->mdns_hostname);
 638
 639         dns_trust_anchor_flush(&m->trust_anchor);
 640         manager_etc_hosts_flush(m);
 641
 642         return mfree(m);
 643 }
 644
 645 int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
 646         _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
 647         union {
 648                 struct cmsghdr header; /* For alignment */
 649                 uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
 650                                + CMSG_SPACE(int) /* ttl/hoplimit */
 651                                + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */];
 652         } control;
 653         union sockaddr_union sa;
 654         struct msghdr mh = {};
 655         struct cmsghdr *cmsg;
 656         struct iovec iov;
 657         ssize_t ms, l;
 658         int r;
 659
 660         assert(m);
 661         assert(fd >= 0);
 662         assert(ret);
 663
 664         ms = next_datagram_size_fd(fd);
 665         if (ms < 0)
 666                 return ms;
 667
 668         r = dns_packet_new(&p, protocol, ms);
 669         if (r < 0)
 670                 return r;
 671
 672         iov.iov_base = DNS_PACKET_DATA(p);
 673         iov.iov_len = p->allocated;
 674
 675         mh.msg_name = &sa.sa;
 676         mh.msg_namelen = sizeof(sa);
 677         mh.msg_iov = &iov;
 678         mh.msg_iovlen = 1;
 679         mh.msg_control = &control;
 680         mh.msg_controllen = sizeof(control);
 681
 682         l = recvmsg(fd, &mh, 0);
 683         if (l == 0)
 684                 return 0;
 685         if (l < 0) {
 686                 if (errno == EAGAIN || errno == EINTR)
 687                         return 0;
 688
 689                 return -errno;
 690         }
 691
 692         assert(!(mh.msg_flags & MSG_CTRUNC));
 693         assert(!(mh.msg_flags & MSG_TRUNC));
 694
 695         p->size = (size_t) l;
 696
 697         p->family = sa.sa.sa_family;
 698         p->ipproto = IPPROTO_UDP;
 699         if (p->family == AF_INET) {
 700                 p->sender.in = sa.in.sin_addr;
 701                 p->sender_port = be16toh(sa.in.sin_port);
 702         } else if (p->family == AF_INET6) {
 703                 p->sender.in6 = sa.in6.sin6_addr;
 704                 p->sender_port = be16toh(sa.in6.sin6_port);
 705                 p->ifindex = sa.in6.sin6_scope_id;
 706         } else
 707                 return -EAFNOSUPPORT;
 708
 709         CMSG_FOREACH(cmsg, &mh) {
 710
 711                 if (cmsg->cmsg_level == IPPROTO_IPV6) {
 712                         assert(p->family == AF_INET6);
 713
 714                         switch (cmsg->cmsg_type) {
 715
 716                         case IPV6_PKTINFO: {
 717                                 struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 718
 719                                 if (p->ifindex <= 0)
 720                                         p->ifindex = i->ipi6_ifindex;
 721
 722                                 p->destination.in6 = i->ipi6_addr;
 723                                 break;
 724                         }
 725
 726                         case IPV6_HOPLIMIT:
 727                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 728                                 break;
 729
 730                         }
 731                 } else if (cmsg->cmsg_level == IPPROTO_IP) {
 732                         assert(p->family == AF_INET);
 733
 734                         switch (cmsg->cmsg_type) {
 735
 736                         case IP_PKTINFO: {
 737                                 struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
 738
 739                                 if (p->ifindex <= 0)
 740                                         p->ifindex = i->ipi_ifindex;
 741
 742                                 p->destination.in = i->ipi_addr;
 743                                 break;
 744                         }
 745
 746                         case IP_TTL:
 747                                 p->ttl = *(int *) CMSG_DATA(cmsg);
 748                                 break;
 749                         }
 750                 }
 751         }
 752
 753         /* The Linux kernel sets the interface index to the loopback
 754          * device if the packet came from the local host since it
 755          * avoids the routing table in such a case. Let's unset the
 756          * interface index in such a case. */
 757         if (p->ifindex == LOOPBACK_IFINDEX)
 758                 p->ifindex = 0;
 759
 760         if (protocol != DNS_PROTOCOL_DNS) {
 761                 /* If we don't know the interface index still, we look for the
 762                  * first local interface with a matching address. Yuck! */
 763                 if (p->ifindex <= 0)
 764                         p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
 765         }
 766
 767         *ret = p;
 768         p = NULL;
 769
 770         return 1;
 771 }
 772
 773 static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
 774         int r;
 775
 776         assert(fd >= 0);
 777         assert(mh);
 778
 779         for (;;) {
 780                 if (sendmsg(fd, mh, flags) >= 0)
 781                         return 0;
 782
 783                 if (errno == EINTR)
 784                         continue;
 785
 786                 if (errno != EAGAIN)
 787                         return -errno;
 788
 789                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 790                 if (r < 0)
 791                         return r;
 792                 if (r == 0)
 793                         return -ETIMEDOUT;
 794         }
 795 }
 796
 797 static int write_loop(int fd, void *message, size_t length) {
 798         int r;
 799
 800         assert(fd >= 0);
 801         assert(message);
 802
 803         for (;;) {
 804                 if (write(fd, message, length) >= 0)
 805                         return 0;
 806
 807                 if (errno == EINTR)
 808                         continue;
 809
 810                 if (errno != EAGAIN)
 811                         return -errno;
 812
 813                 r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
 814                 if (r < 0)
 815                         return r;
 816                 if (r == 0)
 817                         return -ETIMEDOUT;
 818         }
 819 }
 820
 821 int manager_write(Manager *m, int fd, DnsPacket *p) {
 822         int r;
 823
 824         log_debug("Sending %s packet with id %" PRIu16 ".", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p));
 825
 826         r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
 827         if (r < 0)
 828                 return r;
 829
 830         return 0;
 831 }
 832
 833 static int manager_ipv4_send(
 834                 Manager *m,
 835                 int fd,
 836                 int ifindex,
 837                 const struct in_addr *destination,
 838                 uint16_t port,
 839                 const struct in_addr *source,
 840                 DnsPacket *p) {
 841         union sockaddr_union sa = {
 842                 .in.sin_family = AF_INET,
 843         };
 844         union {
 845                 struct cmsghdr header; /* For alignment */
 846                 uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))];
 847         } control;
 848         struct msghdr mh = {};
 849         struct iovec iov;
 850
 851         assert(m);
 852         assert(fd >= 0);
 853         assert(destination);
 854         assert(port > 0);
 855         assert(p);
 856
 857         iov.iov_base = DNS_PACKET_DATA(p);
 858         iov.iov_len = p->size;
 859
 860         sa.in.sin_addr = *destination;
 861         sa.in.sin_port = htobe16(port),
 862
 863         mh.msg_iov = &iov;
 864         mh.msg_iovlen = 1;
 865         mh.msg_name = &sa.sa;
 866         mh.msg_namelen = sizeof(sa.in);
 867
 868         if (ifindex > 0) {
 869                 struct cmsghdr *cmsg;
 870                 struct in_pktinfo *pi;
 871
 872                 zero(control);
 873
 874                 mh.msg_control = &control;
 875                 mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
 876
 877                 cmsg = CMSG_FIRSTHDR(&mh);
 878                 cmsg->cmsg_len = mh.msg_controllen;
 879                 cmsg->cmsg_level = IPPROTO_IP;
 880                 cmsg->cmsg_type = IP_PKTINFO;
 881
 882                 pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
 883                 pi->ipi_ifindex = ifindex;
 884
 885                 if (source)
 886                         pi->ipi_spec_dst = *source;
 887         }
 888
 889         return sendmsg_loop(fd, &mh, 0);
 890 }
 891
 892 static int manager_ipv6_send(
 893                 Manager *m,
 894                 int fd,
 895                 int ifindex,
 896                 const struct in6_addr *destination,
 897                 uint16_t port,
 898                 const struct in6_addr *source,
 899                 DnsPacket *p) {
 900
 901         union sockaddr_union sa = {
 902                 .in6.sin6_family = AF_INET6,
 903         };
 904         union {
 905                 struct cmsghdr header; /* For alignment */
 906                 uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 907         } control;
 908         struct msghdr mh = {};
 909         struct iovec iov;
 910
 911         assert(m);
 912         assert(fd >= 0);
 913         assert(destination);
 914         assert(port > 0);
 915         assert(p);
 916
 917         iov.iov_base = DNS_PACKET_DATA(p);
 918         iov.iov_len = p->size;
 919
 920         sa.in6.sin6_addr = *destination;
 921         sa.in6.sin6_port = htobe16(port),
 922         sa.in6.sin6_scope_id = ifindex;
 923
 924         mh.msg_iov = &iov;
 925         mh.msg_iovlen = 1;
 926         mh.msg_name = &sa.sa;
 927         mh.msg_namelen = sizeof(sa.in6);
 928
 929         if (ifindex > 0) {
 930                 struct cmsghdr *cmsg;
 931                 struct in6_pktinfo *pi;
 932
 933                 zero(control);
 934
 935                 mh.msg_control = &control;
 936                 mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo));
 937
 938                 cmsg = CMSG_FIRSTHDR(&mh);
 939                 cmsg->cmsg_len = mh.msg_controllen;
 940                 cmsg->cmsg_level = IPPROTO_IPV6;
 941                 cmsg->cmsg_type = IPV6_PKTINFO;
 942
 943                 pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
 944                 pi->ipi6_ifindex = ifindex;
 945
 946                 if (source)
 947                         pi->ipi6_addr = *source;
 948         }
 949
 950         return sendmsg_loop(fd, &mh, 0);
 951 }
 952
 953 int manager_send(
 954                 Manager *m,
 955                 int fd,
 956                 int ifindex,
 957                 int family,
 958                 const union in_addr_union *destination,
 959                 uint16_t port,
 960                 const union in_addr_union *source,
 961                 DnsPacket *p) {
 962
 963         assert(m);
 964         assert(fd >= 0);
 965         assert(destination);
 966         assert(port > 0);
 967         assert(p);
 968
 969         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));
 970
 971         if (family == AF_INET)
 972                 return manager_ipv4_send(m, fd, ifindex, &destination->in, port, &source->in, p);
 973         if (family == AF_INET6)
 974                 return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, &source->in6, p);
 975
 976         return -EAFNOSUPPORT;
 977 }
 978
 979 uint32_t manager_find_mtu(Manager *m) {
 980         uint32_t mtu = 0;
 981         Link *l;
 982         Iterator i;
 983
 984         /* If we don't know on which link a DNS packet would be
 985          * delivered, let's find the largest MTU that works on all
 986          * interfaces we know of */
 987
 988         HASHMAP_FOREACH(l, m->links, i) {
 989                 if (l->mtu <= 0)
 990                         continue;
 991
 992                 if (mtu <= 0 || l->mtu < mtu)
 993                         mtu = l->mtu;
 994         }
 995
 996         return mtu;
 997 }
 998
 999 int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
1000         LinkAddress *a;
1001
1002         assert(m);
1003
1004         a = manager_find_link_address(m, family, in_addr);
1005         if (a)
1006                 return a->link->ifindex;
1007
1008         return 0;
1009 }
1010
1011 void manager_refresh_rrs(Manager *m) {
1012         Iterator i;
1013         Link *l;
1014
1015         assert(m);
1016
1017         m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
1018         m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
1019
1020         HASHMAP_FOREACH(l, m->links, i) {
1021                 link_add_rrs(l, true);
1022                 link_add_rrs(l, false);
1023         }
1024 }
1025
1026 int manager_next_hostname(Manager *m) {
1027         const char *p;
1028         uint64_t u, a;
1029         char *h, *k;
1030         int r;
1031
1032         assert(m);
1033
1034         p = strchr(m->llmnr_hostname, 0);
1035         assert(p);
1036
1037         while (p > m->llmnr_hostname) {
1038                 if (!strchr("0123456789", p[-1]))
1039                         break;
1040
1041                 p--;
1042         }
1043
1044         if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
1045                 u = 1;
1046
1047         /* Add a random number to the old value. This way we can avoid
1048          * that two hosts pick the same hostname, win on IPv4 and lose
1049          * on IPv6 (or vice versa), and pick the same hostname
1050          * replacement hostname, ad infinitum. We still want the
1051          * numbers to go up monotonically, hence we just add a random
1052          * value 1..10 */
1053
1054         random_bytes(&a, sizeof(a));
1055         u += 1 + a % 10;
1056
1057         if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->llmnr_hostname), m->llmnr_hostname, u) < 0)
1058                 return -ENOMEM;
1059
1060         r = dns_name_concat(h, "local", &k);
1061         if (r < 0) {
1062                 free(h);
1063                 return r;
1064         }
1065
1066         log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
1067
1068         free(m->llmnr_hostname);
1069         m->llmnr_hostname = h;
1070
1071         free(m->mdns_hostname);
1072         m->mdns_hostname = k;
1073
1074         manager_refresh_rrs(m);
1075
1076         return 0;
1077 }
1078
1079 LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
1080         Iterator i;
1081         Link *l;
1082
1083         assert(m);
1084
1085         HASHMAP_FOREACH(l, m->links, i) {
1086                 LinkAddress *a;
1087
1088                 a = link_find_address(l, family, in_addr);
1089                 if (a)
1090                         return a;
1091         }
1092
1093         return NULL;
1094 }
1095
1096 bool manager_our_packet(Manager *m, DnsPacket *p) {
1097         assert(m);
1098         assert(p);
1099
1100         return !!manager_find_link_address(m, p->family, &p->sender);
1101 }
1102
1103 DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
1104         Link *l;
1105
1106         assert(m);
1107         assert(p);
1108
1109         l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
1110         if (!l)
1111                 return NULL;
1112
1113         switch (p->protocol) {
1114         case DNS_PROTOCOL_LLMNR:
1115                 if (p->family == AF_INET)
1116                         return l->llmnr_ipv4_scope;
1117                 else if (p->family == AF_INET6)
1118                         return l->llmnr_ipv6_scope;
1119
1120                 break;
1121
1122         case DNS_PROTOCOL_MDNS:
1123                 if (p->family == AF_INET)
1124                         return l->mdns_ipv4_scope;
1125                 else if (p->family == AF_INET6)
1126                         return l->mdns_ipv6_scope;
1127
1128                 break;
1129
1130         default:
1131                 break;
1132         }
1133
1134         return NULL;
1135 }
1136
1137 void manager_verify_all(Manager *m) {
1138         DnsScope *s;
1139
1140         assert(m);
1141
1142         LIST_FOREACH(scopes, s, m->dns_scopes)
1143                 dns_zone_verify_all(&s->zone);
1144 }
1145
1146 int manager_is_own_hostname(Manager *m, const char *name) {
1147         int r;
1148
1149         assert(m);
1150         assert(name);
1151
1152         if (m->llmnr_hostname) {
1153                 r = dns_name_equal(name, m->llmnr_hostname);
1154                 if (r != 0)
1155                         return r;
1156         }
1157
1158         if (m->mdns_hostname) {
1159                 r = dns_name_equal(name, m->mdns_hostname);
1160                 if (r != 0)
1161                         return r;
1162         }
1163
1164         if (m->full_hostname)
1165                 return dns_name_equal(name, m->full_hostname);
1166
1167         return 0;
1168 }
1169
1170 int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
1171         DnsServer *s;
1172         Iterator i;
1173         Link *l;
1174         int r;
1175
1176         assert(m);
1177         assert(dns);
1178
1179         r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
1180         if (r < 0)
1181                 return r;
1182
1183         /* First add the system-wide servers and domains */
1184         LIST_FOREACH(servers, s, m->dns_servers) {
1185                 r = ordered_set_put(*dns, s);
1186                 if (r == -EEXIST)
1187                         continue;
1188                 if (r < 0)
1189                         return r;
1190         }
1191
1192         /* Then, add the per-link servers */
1193         HASHMAP_FOREACH(l, m->links, i) {
1194                 LIST_FOREACH(servers, s, l->dns_servers) {
1195                         r = ordered_set_put(*dns, s);
1196                         if (r == -EEXIST)
1197                                 continue;
1198                         if (r < 0)
1199                                 return r;
1200                 }
1201         }
1202
1203         /* If we found nothing, add the fallback servers */
1204         if (ordered_set_isempty(*dns)) {
1205                 LIST_FOREACH(servers, s, m->fallback_dns_servers) {
1206                         r = ordered_set_put(*dns, s);
1207                         if (r == -EEXIST)
1208                                 continue;
1209                         if (r < 0)
1210                                 return r;
1211                 }
1212         }
1213
1214         return 0;
1215 }
1216
1217 /* filter_route is a tri-state:
1218  *   < 0: no filtering
1219  *   = 0 or false: return only domains which should be used for searching
1220  *   > 0 or true: return only domains which are for routing only
1221  */
1222 int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
1223         DnsSearchDomain *d;
1224         Iterator i;
1225         Link *l;
1226         int r;
1227
1228         assert(m);
1229         assert(domains);
1230
1231         r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
1232         if (r < 0)
1233                 return r;
1234
1235         LIST_FOREACH(domains, d, m->search_domains) {
1236
1237                 if (filter_route >= 0 &&
1238                     d->route_only != !!filter_route)
1239                         continue;
1240
1241                 r = ordered_set_put(*domains, d->name);
1242                 if (r == -EEXIST)
1243                         continue;
1244                 if (r < 0)
1245                         return r;
1246         }
1247
1248         HASHMAP_FOREACH(l, m->links, i) {
1249
1250                 LIST_FOREACH(domains, d, l->search_domains) {
1251
1252                         if (filter_route >= 0 &&
1253                             d->route_only != !!filter_route)
1254                                 continue;
1255
1256                         r = ordered_set_put(*domains, d->name);
1257                         if (r == -EEXIST)
1258                                 continue;
1259                         if (r < 0)
1260                                 return r;
1261                 }
1262         }
1263
1264         return 0;
1265 }
1266
1267 DnssecMode manager_get_dnssec_mode(Manager *m) {
1268         assert(m);
1269
1270         if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
1271                 return m->dnssec_mode;
1272
1273         return DNSSEC_NO;
1274 }
1275
1276 bool manager_dnssec_supported(Manager *m) {
1277         DnsServer *server;
1278         Iterator i;
1279         Link *l;
1280
1281         assert(m);
1282
1283         if (manager_get_dnssec_mode(m) == DNSSEC_NO)
1284                 return false;
1285
1286         server = manager_get_dns_server(m);
1287         if (server && !dns_server_dnssec_supported(server))
1288                 return false;
1289
1290         HASHMAP_FOREACH(l, m->links, i)
1291                 if (!link_dnssec_supported(l))
1292                         return false;
1293
1294         return true;
1295 }
1296
1297 void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
1298
1299         assert(verdict >= 0);
1300         assert(verdict < _DNSSEC_VERDICT_MAX);
1301
1302         if (log_get_max_level() >= LOG_DEBUG) {
1303                 char s[DNS_RESOURCE_KEY_STRING_MAX];
1304
1305                 log_debug("Found verdict for lookup %s: %s",
1306                           dns_resource_key_to_string(key, s, sizeof s),
1307                           dnssec_verdict_to_string(verdict));
1308         }
1309
1310         m->n_dnssec_verdict[verdict]++;
1311 }
1312
1313 bool manager_routable(Manager *m, int family) {
1314         Iterator i;
1315         Link *l;
1316
1317         assert(m);
1318
1319         /* Returns true if the host has at least one interface with a routable address of the specified type */
1320
1321         HASHMAP_FOREACH(l, m->links, i)
1322                 if (link_relevant(l, family, false))
1323                         return true;
1324
1325         return false;
1326 }
1327
1328 void manager_flush_caches(Manager *m) {
1329         DnsScope *scope;
1330
1331         assert(m);
1332
1333         LIST_FOREACH(scopes, scope, m->dns_scopes)
1334                 dns_cache_flush(&scope->cache);
1335
1336         log_info("Flushed all caches.");
1337 }
1338
1339 void manager_cleanup_saved_user(Manager *m) {
1340         _cleanup_closedir_ DIR *d = NULL;
1341         struct dirent *de;
1342         int r;
1343
1344         assert(m);
1345
1346         /* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
1347          * anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
1348          * be restarted without losing this data. */
1349
1350         d = opendir("/run/systemd/resolve/netif/");
1351         if (!d) {
1352                 if (errno == ENOENT)
1353                         return;
1354
1355                 log_warning_errno(errno, "Failed to open interface directory: %m");
1356                 return;
1357         }
1358
1359         FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
1360                 _cleanup_free_ char *p = NULL;
1361                 int ifindex;
1362                 Link *l;
1363
1364                 if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
1365                         continue;
1366
1367                 if (dot_or_dot_dot(de->d_name))
1368                         continue;
1369
1370                 r = parse_ifindex(de->d_name, &ifindex);
1371                 if (r < 0) /* Probably some temporary file from a previous run. Delete it */
1372                         goto rm;
1373
1374                 l = hashmap_get(m->links, INT_TO_PTR(ifindex));
1375                 if (!l) /* link vanished */
1376                         goto rm;
1377
1378                 if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
1379                         goto rm;
1380
1381                 continue;
1382
1383         rm:
1384                 p = strappend("/run/systemd/resolve/netif/", de->d_name);
1385                 if (!p) {
1386                         log_oom();
1387                         return;
1388                 }
1389
1390                 (void) unlink(p);
1391         }
1392 }