git.meshlink.io Git - catta/blob - avahi-core/iface.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of avahi.
   5
   6   avahi is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation; either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   avahi is distributed in the hope that it will be useful, but WITHOUT
  12   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13   or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  14   Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with avahi; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <string.h>
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <netinet/in.h>
  31 #include <sys/types.h>
  32 #include <sys/socket.h>
  33
  34 #include <avahi-common/error.h>
  35 #include <avahi-common/malloc.h>
  36 #include <avahi-common/domain.h>
  37
  38 #include "iface.h"
  39 #include "dns.h"
  40 #include "socket.h"
  41 #include "announce.h"
  42 #include "util.h"
  43 #include "log.h"
  44 #include "multicast-lookup.h"
  45 #include "querier.h"
  46
  47 void avahi_interface_address_update_rrs(AvahiInterfaceAddress *a, int remove_rrs) {
  48     AvahiInterfaceMonitor *m;
  49
  50     assert(a);
  51     m = a->monitor;
  52
  53     if (a->interface->announcing &&
  54         m->list_complete &&
  55         avahi_interface_address_is_relevant(a) &&
  56         !remove_rrs &&
  57         m->server->config.publish_addresses &&
  58         (m->server->state == AVAHI_SERVER_RUNNING ||
  59         m->server->state == AVAHI_SERVER_REGISTERING)) {
  60
  61         /* Fill the entry group */
  62         if (!a->entry_group)
  63             a->entry_group = avahi_s_entry_group_new(m->server, avahi_host_rr_entry_group_callback, NULL);
  64
  65         if (!a->entry_group) /* OOM */
  66             return;
  67
  68         if (avahi_s_entry_group_is_empty(a->entry_group)) {
  69             char t[AVAHI_ADDRESS_STR_MAX];
  70             avahi_address_snprint(t, sizeof(t), &a->address);
  71
  72             avahi_log_info("Registering new address record for %s on %s.", t, a->interface->hardware->name);
  73
  74             if (avahi_server_add_address(m->server, a->entry_group, a->interface->hardware->index, a->interface->protocol, 0, NULL, &a->address) < 0) {
  75                 avahi_log_warn(__FILE__": avahi_server_add_address() failed: %s", avahi_strerror(m->server->error));
  76                 avahi_s_entry_group_free(a->entry_group);
  77                 a->entry_group = NULL;
  78                 return;
  79             }
  80
  81             avahi_s_entry_group_commit(a->entry_group);
  82         }
  83     } else {
  84
  85         /* Clear the entry group */
  86
  87         if (a->entry_group && !avahi_s_entry_group_is_empty(a->entry_group)) {
  88             char t[AVAHI_ADDRESS_STR_MAX];
  89             avahi_address_snprint(t, sizeof(t), &a->address);
  90
  91             if (avahi_s_entry_group_get_state(a->entry_group) == AVAHI_ENTRY_GROUP_REGISTERING &&
  92                 m->server->state == AVAHI_SERVER_REGISTERING)
  93                 avahi_server_decrease_host_rr_pending(m->server);
  94
  95             avahi_log_info("Withdrawing address record for %s on %s.", t, a->interface->hardware->name);
  96
  97             avahi_s_entry_group_reset(a->entry_group);
  98         }
  99     }
 100 }
 101
 102 void avahi_interface_update_rrs(AvahiInterface *i, int remove_rrs) {
 103     AvahiInterfaceAddress *a;
 104
 105     assert(i);
 106
 107     for (a = i->addresses; a; a = a->address_next)
 108         avahi_interface_address_update_rrs(a, remove_rrs);
 109 }
 110
 111 void avahi_hw_interface_update_rrs(AvahiHwInterface *hw, int remove_rrs) {
 112     AvahiInterface *i;
 113     AvahiInterfaceMonitor *m;
 114
 115     assert(hw);
 116     m = hw->monitor;
 117
 118     for (i = hw->interfaces; i; i = i->by_hardware_next)
 119         avahi_interface_update_rrs(i, remove_rrs);
 120
 121     if (m->list_complete &&
 122         !remove_rrs &&
 123         m->server->config.publish_workstation &&
 124         (m->server->state == AVAHI_SERVER_RUNNING)) {
 125
 126         if (!hw->entry_group)
 127             hw->entry_group = avahi_s_entry_group_new(m->server, avahi_host_rr_entry_group_callback, NULL);
 128
 129         if (!hw->entry_group)
 130             return; /* OOM */
 131
 132         if (avahi_s_entry_group_is_empty(hw->entry_group)) {
 133             char name[AVAHI_LABEL_MAX], mac[256];
 134
 135             avahi_format_mac_address(mac, sizeof(mac), hw->mac_address, hw->mac_address_size);
 136             snprintf(name, sizeof(name), "%s [%s]", m->server->host_name, mac);
 137
 138             if (avahi_server_add_service(m->server, hw->entry_group, hw->index, AVAHI_PROTO_UNSPEC, 0, name, "_workstation._tcp", NULL, NULL, 9, NULL) < 0) {
 139                 avahi_log_warn(__FILE__": avahi_server_add_service() failed: %s", avahi_strerror(m->server->error));
 140                 avahi_s_entry_group_free(hw->entry_group);
 141                 hw->entry_group = NULL;
 142             } else
 143                 avahi_s_entry_group_commit(hw->entry_group);
 144         }
 145
 146     } else {
 147
 148         if (hw->entry_group && !avahi_s_entry_group_is_empty(hw->entry_group)) {
 149
 150             if (avahi_s_entry_group_get_state(hw->entry_group) == AVAHI_ENTRY_GROUP_REGISTERING)
 151                 avahi_server_decrease_host_rr_pending(m->server);
 152
 153             avahi_s_entry_group_reset(hw->entry_group);
 154         }
 155     }
 156 }
 157
 158 void avahi_interface_monitor_update_rrs(AvahiInterfaceMonitor *m, int remove_rrs) {
 159     AvahiHwInterface *hw;
 160
 161     assert(m);
 162
 163     for (hw = m->hw_interfaces; hw; hw = hw->hardware_next)
 164         avahi_hw_interface_update_rrs(hw, remove_rrs);
 165 }
 166
 167 static int interface_mdns_mcast_join(AvahiInterface *i, int join) {
 168     char at[AVAHI_ADDRESS_STR_MAX];
 169     int r;
 170     assert(i);
 171
 172     if (!!join  == !!i->mcast_joined)
 173         return 0;
 174
 175     if (join) {
 176         AvahiInterfaceAddress *a;
 177
 178         /* Look if there's an address with global scope */
 179         for (a = i->addresses; a; a = a->address_next)
 180             if (a->global_scope)
 181                 break;
 182
 183         /* No address with a global scope has been found, so let's use
 184          * any. */
 185         if (!a)
 186             a = i->addresses;
 187
 188         /* Hmm, there is no address available. */
 189         if (!a) {
 190             avahi_log_warn(__FILE__": interface_mdns_mcast_join() called but no local address available.");
 191             return -1;
 192         }
 193
 194         i->local_mcast_address = a->address;
 195     }
 196
 197     avahi_log_info("%s mDNS multicast group on interface %s.%s with address %s.",
 198                    join ? "Joining" : "Leaving",
 199                    i->hardware->name,
 200                    avahi_proto_to_string(i->protocol),
 201                    avahi_address_snprint(at, sizeof(at), &i->local_mcast_address));
 202
 203     if (i->protocol == AVAHI_PROTO_INET6)
 204         r = avahi_mdns_mcast_join_ipv6(i->monitor->server->fd_ipv6, &i->local_mcast_address.data.ipv6, i->hardware->index, join);
 205     else {
 206         assert(i->protocol == AVAHI_PROTO_INET);
 207
 208         r = avahi_mdns_mcast_join_ipv4(i->monitor->server->fd_ipv4, &i->local_mcast_address.data.ipv4, i->hardware->index, join);
 209     }
 210
 211     if (r < 0)
 212         i->mcast_joined = 0;
 213     else
 214         i->mcast_joined = join;
 215
 216     return 0;
 217 }
 218
 219 static int interface_mdns_mcast_rejoin(AvahiInterface *i) {
 220     AvahiInterfaceAddress *a, *usable = NULL, *found = NULL;
 221     assert(i);
 222
 223     if (!i->mcast_joined)
 224         return 0;
 225
 226     /* Check whether old address we joined with is still available. If
 227      * not, rejoin using an other address. */
 228
 229     for (a = i->addresses; a; a = a->address_next) {
 230         if (a->global_scope && !usable)
 231             usable = a;
 232
 233         if (avahi_address_cmp(&a->address, &i->local_mcast_address) == 0) {
 234
 235             if (a->global_scope)
 236                 /* No action necessary: the address still exists and
 237                  * has global scope. */
 238                 return 0;
 239
 240             found = a;
 241         }
 242     }
 243
 244     if (found && !usable)
 245         /* No action necessary: the address still exists and no better one has been found */
 246         return 0;
 247
 248     interface_mdns_mcast_join(i, 0);
 249     return interface_mdns_mcast_join(i, 1);
 250 }
 251
 252 void avahi_interface_address_free(AvahiInterfaceAddress *a) {
 253     assert(a);
 254     assert(a->interface);
 255
 256     avahi_interface_address_update_rrs(a, 1);
 257     AVAHI_LLIST_REMOVE(AvahiInterfaceAddress, address, a->interface->addresses, a);
 258
 259     if (a->entry_group)
 260         avahi_s_entry_group_free(a->entry_group);
 261
 262     interface_mdns_mcast_rejoin(a->interface);
 263
 264     avahi_free(a);
 265 }
 266
 267 void avahi_interface_free(AvahiInterface *i, int send_goodbye) {
 268     assert(i);
 269
 270     /* Handle goodbyes and remove announcers */
 271     avahi_goodbye_interface(i->monitor->server, i, send_goodbye, 1);
 272     avahi_response_scheduler_force(i->response_scheduler);
 273     assert(!i->announcers);
 274
 275     if (i->mcast_joined)
 276         interface_mdns_mcast_join(i, 0);
 277
 278     /* Remove queriers */
 279     avahi_querier_free_all(i);
 280     avahi_hashmap_free(i->queriers_by_key);
 281
 282     /* Remove local RRs */
 283     avahi_interface_update_rrs(i, 1);
 284
 285     while (i->addresses)
 286         avahi_interface_address_free(i->addresses);
 287
 288     avahi_response_scheduler_free(i->response_scheduler);
 289     avahi_query_scheduler_free(i->query_scheduler);
 290     avahi_probe_scheduler_free(i->probe_scheduler);
 291     avahi_cache_free(i->cache);
 292
 293     AVAHI_LLIST_REMOVE(AvahiInterface, interface, i->monitor->interfaces, i);
 294     AVAHI_LLIST_REMOVE(AvahiInterface, by_hardware, i->hardware->interfaces, i);
 295
 296     avahi_free(i);
 297 }
 298
 299 void avahi_hw_interface_free(AvahiHwInterface *hw, int send_goodbye) {
 300     assert(hw);
 301
 302     avahi_hw_interface_update_rrs(hw, 1);
 303
 304     while (hw->interfaces)
 305         avahi_interface_free(hw->interfaces, send_goodbye);
 306
 307     if (hw->entry_group)
 308         avahi_s_entry_group_free(hw->entry_group);
 309
 310     AVAHI_LLIST_REMOVE(AvahiHwInterface, hardware, hw->monitor->hw_interfaces, hw);
 311     avahi_hashmap_remove(hw->monitor->hashmap, &hw->index);
 312
 313     avahi_free(hw->name);
 314     avahi_free(hw);
 315 }
 316
 317 AvahiInterface* avahi_interface_new(AvahiInterfaceMonitor *m, AvahiHwInterface *hw, AvahiProtocol protocol) {
 318     AvahiInterface *i;
 319
 320     assert(m);
 321     assert(hw);
 322     assert(AVAHI_PROTO_VALID(protocol));
 323
 324     if (!(i = avahi_new(AvahiInterface, 1)))
 325         goto fail; /* OOM */
 326
 327     i->monitor = m;
 328     i->hardware = hw;
 329     i->protocol = protocol;
 330     i->announcing = 0;
 331     i->mcast_joined = 0;
 332
 333     AVAHI_LLIST_HEAD_INIT(AvahiInterfaceAddress, i->addresses);
 334     AVAHI_LLIST_HEAD_INIT(AvahiAnnouncer, i->announcers);
 335
 336     AVAHI_LLIST_HEAD_INIT(AvahiQuerier, i->queriers);
 337     i->queriers_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, NULL, NULL);
 338
 339     i->cache = avahi_cache_new(m->server, i);
 340     i->response_scheduler = avahi_response_scheduler_new(i);
 341     i->query_scheduler = avahi_query_scheduler_new(i);
 342     i->probe_scheduler = avahi_probe_scheduler_new(i);
 343
 344     if (!i->cache || !i->response_scheduler || !i->query_scheduler || !i->probe_scheduler)
 345         goto fail; /* OOM */
 346
 347     AVAHI_LLIST_PREPEND(AvahiInterface, by_hardware, hw->interfaces, i);
 348     AVAHI_LLIST_PREPEND(AvahiInterface, interface, m->interfaces, i);
 349
 350     return i;
 351
 352 fail:
 353
 354     if (i) {
 355         if (i->cache)
 356             avahi_cache_free(i->cache);
 357         if (i->response_scheduler)
 358             avahi_response_scheduler_free(i->response_scheduler);
 359         if (i->query_scheduler)
 360             avahi_query_scheduler_free(i->query_scheduler);
 361         if (i->probe_scheduler)
 362             avahi_probe_scheduler_free(i->probe_scheduler);
 363     }
 364
 365     return NULL;
 366 }
 367
 368 AvahiHwInterface *avahi_hw_interface_new(AvahiInterfaceMonitor *m, AvahiIfIndex idx) {
 369     AvahiHwInterface *hw;
 370
 371     assert(m);
 372     assert(AVAHI_IF_VALID(idx));
 373
 374     if  (!(hw = avahi_new(AvahiHwInterface, 1)))
 375         return NULL;
 376
 377     hw->monitor = m;
 378     hw->name = NULL;
 379     hw->flags_ok = 0;
 380     hw->mtu = 1500;
 381     hw->index = idx;
 382     hw->mac_address_size = 0;
 383     hw->entry_group = NULL;
 384
 385     AVAHI_LLIST_HEAD_INIT(AvahiInterface, hw->interfaces);
 386     AVAHI_LLIST_PREPEND(AvahiHwInterface, hardware, m->hw_interfaces, hw);
 387
 388     avahi_hashmap_insert(m->hashmap, &hw->index, hw);
 389
 390     if (m->server->fd_ipv4 >= 0)
 391         avahi_interface_new(m, hw, AVAHI_PROTO_INET);
 392     if (m->server->fd_ipv6 >= 0)
 393         avahi_interface_new(m, hw, AVAHI_PROTO_INET6);
 394
 395     return hw;
 396 }
 397
 398 AvahiInterfaceAddress *avahi_interface_address_new(AvahiInterfaceMonitor *m, AvahiInterface *i, const AvahiAddress *addr, unsigned prefix_len) {
 399     AvahiInterfaceAddress *a;
 400
 401     assert(m);
 402     assert(i);
 403
 404     if (!(a = avahi_new(AvahiInterfaceAddress, 1)))
 405         return NULL;
 406
 407     a->interface = i;
 408     a->monitor = m;
 409     a->address = *addr;
 410     a->prefix_len = prefix_len;
 411     a->global_scope = 0;
 412     a->entry_group = NULL;
 413
 414     AVAHI_LLIST_PREPEND(AvahiInterfaceAddress, address, i->addresses, a);
 415
 416     return a;
 417 }
 418
 419 void avahi_interface_check_relevant(AvahiInterface *i) {
 420     int b;
 421     AvahiInterfaceMonitor *m;
 422
 423     assert(i);
 424     m = i->monitor;
 425
 426     b = avahi_interface_is_relevant(i);
 427
 428     if (m->list_complete && b && !i->announcing) {
 429         avahi_log_info("New relevant interface %s.%s for mDNS.", i->hardware->name, avahi_proto_to_string(i->protocol));
 430
 431         interface_mdns_mcast_join(i, 1);
 432
 433         i->announcing = 1;
 434         avahi_announce_interface(m->server, i);
 435         avahi_multicast_lookup_engine_new_interface(m->server->multicast_lookup_engine, i);
 436     } else if (!b && i->announcing) {
 437         avahi_log_info("Interface %s.%s no longer relevant for mDNS.", i->hardware->name, avahi_proto_to_string(i->protocol));
 438
 439         interface_mdns_mcast_join(i, 0);
 440
 441         avahi_goodbye_interface(m->server, i, 0, 1);
 442         avahi_querier_free_all(i);
 443
 444         avahi_response_scheduler_clear(i->response_scheduler);
 445         avahi_query_scheduler_clear(i->query_scheduler);
 446         avahi_probe_scheduler_clear(i->probe_scheduler);
 447         avahi_cache_flush(i->cache);
 448
 449         i->announcing = 0;
 450
 451     } else
 452         interface_mdns_mcast_rejoin(i);
 453 }
 454
 455 void avahi_hw_interface_check_relevant(AvahiHwInterface *hw) {
 456     AvahiInterface *i;
 457
 458     assert(hw);
 459
 460     for (i = hw->interfaces; i; i = i->by_hardware_next)
 461         avahi_interface_check_relevant(i);
 462 }
 463
 464 void avahi_interface_monitor_check_relevant(AvahiInterfaceMonitor *m) {
 465     AvahiInterface *i;
 466
 467     assert(m);
 468
 469     for (i = m->interfaces; i; i = i->interface_next)
 470         avahi_interface_check_relevant(i);
 471 }
 472
 473 AvahiInterfaceMonitor *avahi_interface_monitor_new(AvahiServer *s) {
 474     AvahiInterfaceMonitor *m = NULL;
 475
 476     if (!(m = avahi_new0(AvahiInterfaceMonitor, 1)))
 477         return NULL; /* OOM */
 478
 479     m->server = s;
 480     m->list_complete = 0;
 481     m->hashmap = avahi_hashmap_new(avahi_int_hash, avahi_int_equal, NULL, NULL);
 482
 483     AVAHI_LLIST_HEAD_INIT(AvahiInterface, m->interfaces);
 484     AVAHI_LLIST_HEAD_INIT(AvahiHwInterface, m->hw_interfaces);
 485
 486     if (avahi_interface_monitor_init_osdep(m) < 0)
 487         goto fail;
 488
 489     return m;
 490
 491 fail:
 492     avahi_interface_monitor_free(m);
 493     return NULL;
 494 }
 495
 496 void avahi_interface_monitor_free(AvahiInterfaceMonitor *m) {
 497     assert(m);
 498
 499     while (m->hw_interfaces)
 500         avahi_hw_interface_free(m->hw_interfaces, 1);
 501
 502     assert(!m->interfaces);
 503
 504     avahi_interface_monitor_free_osdep(m);
 505
 506     if (m->hashmap)
 507         avahi_hashmap_free(m->hashmap);
 508
 509     avahi_free(m);
 510 }
 511
 512
 513 AvahiInterface* avahi_interface_monitor_get_interface(AvahiInterfaceMonitor *m, AvahiIfIndex idx, AvahiProtocol protocol) {
 514     AvahiHwInterface *hw;
 515     AvahiInterface *i;
 516
 517     assert(m);
 518     assert(idx >= 0);
 519     assert(protocol != AVAHI_PROTO_UNSPEC);
 520
 521     if (!(hw = avahi_interface_monitor_get_hw_interface(m, idx)))
 522         return NULL;
 523
 524     for (i = hw->interfaces; i; i = i->by_hardware_next)
 525         if (i->protocol == protocol)
 526             return i;
 527
 528     return NULL;
 529 }
 530
 531 AvahiHwInterface* avahi_interface_monitor_get_hw_interface(AvahiInterfaceMonitor *m, AvahiIfIndex idx) {
 532     assert(m);
 533     assert(idx > 0);
 534
 535     return avahi_hashmap_lookup(m->hashmap, &idx);
 536 }
 537
 538 AvahiInterfaceAddress* avahi_interface_monitor_get_address(AvahiInterfaceMonitor *m, AvahiInterface *i, const AvahiAddress *raddr) {
 539     AvahiInterfaceAddress *ia;
 540
 541     assert(m);
 542     assert(i);
 543     assert(raddr);
 544
 545     for (ia = i->addresses; ia; ia = ia->address_next)
 546         if (avahi_address_cmp(&ia->address, raddr) == 0)
 547             return ia;
 548
 549     return NULL;
 550 }
 551
 552 void avahi_interface_send_packet_unicast(AvahiInterface *i, AvahiDnsPacket *p, const AvahiAddress *a, uint16_t port) {
 553     assert(i);
 554     assert(p);
 555
 556     if (!avahi_interface_is_relevant(i))
 557         return;
 558
 559     assert(!a || a->proto == i->protocol);
 560
 561     if (i->protocol == AVAHI_PROTO_INET && i->monitor->server->fd_ipv4 >= 0)
 562         avahi_send_dns_packet_ipv4(i->monitor->server->fd_ipv4, i->hardware->index, p, i->mcast_joined ? &i->local_mcast_address.data.ipv4 : NULL, a ? &a->data.ipv4 : NULL, port);
 563     else if (i->protocol == AVAHI_PROTO_INET6 && i->monitor->server->fd_ipv6 >= 0)
 564         avahi_send_dns_packet_ipv6(i->monitor->server->fd_ipv6, i->hardware->index, p, i->mcast_joined ? &i->local_mcast_address.data.ipv6 : NULL, a ? &a->data.ipv6 : NULL, port);
 565 }
 566
 567 void avahi_interface_send_packet(AvahiInterface *i, AvahiDnsPacket *p) {
 568     assert(i);
 569     assert(p);
 570
 571     avahi_interface_send_packet_unicast(i, p, NULL, 0);
 572 }
 573
 574 int avahi_interface_post_query(AvahiInterface *i, AvahiKey *key, int immediately, unsigned *ret_id) {
 575     assert(i);
 576     assert(key);
 577
 578     if (avahi_interface_is_relevant(i))
 579         return avahi_query_scheduler_post(i->query_scheduler, key, immediately, ret_id);
 580
 581     return 0;
 582 }
 583
 584 int avahi_interface_withraw_query(AvahiInterface *i, unsigned id) {
 585
 586     return avahi_query_scheduler_withdraw_by_id(i->query_scheduler, id);
 587 }
 588
 589 int avahi_interface_post_response(AvahiInterface *i, AvahiRecord *record, int flush_cache, const AvahiAddress *querier, int immediately) {
 590     assert(i);
 591     assert(record);
 592
 593     if (avahi_interface_is_relevant(i))
 594         return avahi_response_scheduler_post(i->response_scheduler, record, flush_cache, querier, immediately);
 595
 596     return 0;
 597 }
 598
 599 int avahi_interface_post_probe(AvahiInterface *i, AvahiRecord *record, int immediately) {
 600     assert(i);
 601     assert(record);
 602
 603     if (avahi_interface_is_relevant(i))
 604         return avahi_probe_scheduler_post(i->probe_scheduler, record, immediately);
 605
 606     return 0;
 607 }
 608
 609 int avahi_dump_caches(AvahiInterfaceMonitor *m, AvahiDumpCallback callback, void* userdata) {
 610     AvahiInterface *i;
 611     assert(m);
 612
 613     for (i = m->interfaces; i; i = i->interface_next) {
 614         if (avahi_interface_is_relevant(i)) {
 615             char ln[256];
 616             snprintf(ln, sizeof(ln), ";;; INTERFACE %s.%s ;;;", i->hardware->name, avahi_proto_to_string(i->protocol));
 617             callback(ln, userdata);
 618             if (avahi_cache_dump(i->cache, callback, userdata) < 0)
 619                 return -1;
 620         }
 621     }
 622
 623     return 0;
 624 }
 625
 626 int avahi_interface_is_relevant(AvahiInterface *i) {
 627     AvahiInterfaceAddress *a;
 628     int relevant_address;
 629
 630     assert(i);
 631
 632     relevant_address = 0;
 633
 634     for (a = i->addresses; a; a = a->address_next)
 635         if (avahi_interface_address_is_relevant(a)) {
 636             relevant_address = 1;
 637             break;
 638         }
 639
 640     return i->hardware->flags_ok && relevant_address;
 641 }
 642
 643 int avahi_interface_address_is_relevant(AvahiInterfaceAddress *a) {
 644     AvahiInterfaceAddress *b;
 645     assert(a);
 646
 647     /* Publish public IP addresses */
 648     if (a->global_scope)
 649         return 1;
 650     else {
 651
 652         /* Publish link local IP addresses if they are the only ones on the link */
 653         for (b = a->interface->addresses; b; b = b->address_next) {
 654             if (b == a)
 655                 continue;
 656
 657             if (b->global_scope)
 658                 return 0;
 659         }
 660
 661         return 1;
 662     }
 663
 664     return 0;
 665 }
 666
 667 int avahi_interface_match(AvahiInterface *i, AvahiIfIndex idx, AvahiProtocol protocol) {
 668     assert(i);
 669
 670     if (idx != AVAHI_IF_UNSPEC && idx != i->hardware->index)
 671         return 0;
 672
 673     if (protocol != AVAHI_PROTO_UNSPEC && protocol != i->protocol)
 674         return 0;
 675
 676     return 1;
 677 }
 678
 679 void avahi_interface_monitor_walk(AvahiInterfaceMonitor *m, AvahiIfIndex interface, AvahiProtocol protocol, AvahiInterfaceMonitorWalkCallback callback, void* userdata) {
 680     assert(m);
 681     assert(callback);
 682
 683     if (interface != AVAHI_IF_UNSPEC) {
 684         if (protocol != AVAHI_PROTO_UNSPEC) {
 685             AvahiInterface *i;
 686
 687             if ((i = avahi_interface_monitor_get_interface(m, interface, protocol)))
 688                 callback(m, i, userdata);
 689
 690         } else {
 691             AvahiHwInterface *hw;
 692             AvahiInterface *i;
 693
 694             if ((hw = avahi_interface_monitor_get_hw_interface(m, interface)))
 695                 for (i = hw->interfaces; i; i = i->by_hardware_next)
 696                     if (avahi_interface_match(i, interface, protocol))
 697                         callback(m, i, userdata);
 698         }
 699
 700     } else {
 701         AvahiInterface *i;
 702
 703         for (i = m->interfaces; i; i = i->interface_next)
 704             if (avahi_interface_match(i, interface, protocol))
 705                 callback(m, i, userdata);
 706     }
 707 }
 708
 709
 710 int avahi_address_is_local(AvahiInterfaceMonitor *m, const AvahiAddress *a) {
 711     AvahiInterface *i;
 712     AvahiInterfaceAddress *ia;
 713     assert(m);
 714     assert(a);
 715
 716     for (i = m->interfaces; i; i = i->interface_next)
 717         for (ia = i->addresses; ia; ia = ia->address_next)
 718             if (avahi_address_cmp(a, &ia->address) == 0)
 719                 return 1;
 720
 721     return 0;
 722 }
 723
 724 int avahi_interface_address_on_link(AvahiInterface *i, const AvahiAddress *a) {
 725     AvahiInterfaceAddress *ia;
 726
 727     assert(i);
 728     assert(a);
 729
 730     if (a->proto != i->protocol)
 731         return 0;
 732
 733     for (ia = i->addresses; ia; ia = ia->address_next) {
 734
 735         if (a->proto == AVAHI_PROTO_INET) {
 736             uint32_t m;
 737
 738             m = ~(((uint32_t) -1) >> ia->prefix_len);
 739
 740             if ((ntohl(a->data.ipv4.address) & m) == (ntohl(ia->address.data.ipv4.address) & m))
 741                 return 1;
 742         } else {
 743             unsigned j;
 744             unsigned char pl;
 745             assert(a->proto == AVAHI_PROTO_INET6);
 746
 747             pl = ia->prefix_len;
 748
 749             for (j = 0; j < 16; j++) {
 750                 uint8_t m;
 751
 752                 if (pl == 0)
 753                     return 1;
 754
 755                 if (pl >= 8) {
 756                     m = 0xFF;
 757                     pl -= 8;
 758                 } else {
 759                     m = ~(0xFF >> pl);
 760                     pl = 0;
 761                 }
 762
 763                 if ((a->data.ipv6.address[j] & m) != (ia->address.data.ipv6.address[j] & m))
 764                     break;
 765             }
 766         }
 767     }
 768
 769     return 0;
 770 }
 771
 772 int avahi_interface_has_address(AvahiInterfaceMonitor *m, AvahiIfIndex iface, const AvahiAddress *a) {
 773     AvahiInterface *i;
 774     AvahiInterfaceAddress *j;
 775
 776     assert(m);
 777     assert(iface != AVAHI_IF_UNSPEC);
 778     assert(a);
 779
 780     if (!(i = avahi_interface_monitor_get_interface(m, iface, a->proto)))
 781         return 0;
 782
 783     for (j = i->addresses; j; j = j->address_next)
 784         if (avahi_address_cmp(a, &j->address) == 0)
 785             return 1;
 786
 787     return 0;
 788 }
 789
 790 AvahiIfIndex avahi_find_interface_for_address(AvahiInterfaceMonitor *m, const AvahiAddress *a) {
 791     AvahiInterface *i;
 792     assert(m);
 793
 794     /* Some stupid OS don't support passing the interface index when a
 795      * packet is recieved. We have to work around that limitation by
 796      * looking for an interface that has the incoming address
 797      * attached. This is sometimes ambiguous, but we have to live with
 798      * it. */
 799
 800     for (i = m->interfaces; i; i = i->interface_next) {
 801         AvahiInterfaceAddress *ai;
 802
 803         if (i->protocol != a->proto)
 804             continue;
 805
 806         for (ai = i->addresses; ai; ai = ai->address_next)
 807             if (avahi_address_cmp(a, &ai->address) == 0)
 808                 return i->hardware->index;
 809     }
 810
 811     return AVAHI_IF_UNSPEC;
 812 }