git.meshlink.io Git - catta/blob - src/resolve-address.c

   1 /***
   2   This file is part of avahi.
   3
   4   avahi is free software; you can redistribute it and/or modify it
   5   under the terms of the GNU Lesser General Public License as
   6   published by the Free Software Foundation; either version 2.1 of the
   7   License, or (at your option) any later version.
   8
   9   avahi is distributed in the hope that it will be useful, but WITHOUT
  10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11   or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  12   Public License for more details.
  13
  14   You should have received a copy of the GNU Lesser General Public
  15   License along with avahi; if not, write to the Free Software
  16   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  17   USA.
  18 ***/
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <stdlib.h>
  25
  26 #include <avahi/timeval.h>
  27 #include <avahi/malloc.h>
  28 #include <avahi/error.h>
  29 #include <avahi/domain.h>
  30
  31 #include "browse.h"
  32
  33 #define TIMEOUT_MSEC 5000
  34
  35 struct AvahiSAddressResolver {
  36     AvahiServer *server;
  37     AvahiAddress address;
  38
  39     AvahiSRecordBrowser *record_browser;
  40
  41     AvahiSAddressResolverCallback callback;
  42     void* userdata;
  43
  44     AvahiRecord *ptr_record;
  45     AvahiIfIndex interface;
  46     AvahiProtocol protocol;
  47     AvahiLookupResultFlags flags;
  48
  49     int retry_with_multicast;
  50     AvahiKey *key;
  51
  52     AvahiTimeEvent *time_event;
  53
  54     AVAHI_LLIST_FIELDS(AvahiSAddressResolver, resolver);
  55 };
  56
  57 static void finish(AvahiSAddressResolver *r, AvahiResolverEvent event) {
  58     assert(r);
  59
  60     if (r->time_event) {
  61         avahi_time_event_free(r->time_event);
  62         r->time_event = NULL;
  63     }
  64
  65     switch (event) {
  66         case AVAHI_RESOLVER_FAILURE:
  67             r->callback(r, r->interface, r->protocol, event, &r->address, NULL, r->flags, r->userdata);
  68             break;
  69
  70         case AVAHI_RESOLVER_FOUND:
  71             assert(r->ptr_record);
  72             r->callback(r, r->interface, r->protocol, event, &r->address, r->ptr_record->data.ptr.name, r->flags, r->userdata);
  73             break;
  74     }
  75 }
  76
  77 static void time_event_callback(AvahiTimeEvent *e, void *userdata) {
  78     AvahiSAddressResolver *r = userdata;
  79
  80     assert(e);
  81     assert(r);
  82
  83     avahi_server_set_errno(r->server, AVAHI_ERR_TIMEOUT);
  84     finish(r, AVAHI_RESOLVER_FAILURE);
  85 }
  86
  87 static void start_timeout(AvahiSAddressResolver *r) {
  88     struct timeval tv;
  89     assert(r);
  90
  91     if (r->time_event)
  92         return;
  93
  94     avahi_elapse_time(&tv, TIMEOUT_MSEC, 0);
  95     r->time_event = avahi_time_event_new(r->server->time_event_queue, &tv, time_event_callback, r);
  96 }
  97
  98 static void record_browser_callback(
  99     AvahiSRecordBrowser*rr,
 100     AvahiIfIndex interface,
 101     AvahiProtocol protocol,
 102     AvahiBrowserEvent event,
 103     AvahiRecord *record,
 104     AvahiLookupResultFlags flags,
 105     void* userdata) {
 106
 107     AvahiSAddressResolver *r = userdata;
 108
 109     assert(rr);
 110     assert(r);
 111
 112     switch (event) {
 113         case AVAHI_BROWSER_NEW:
 114             assert(record);
 115             assert(record->key->type == AVAHI_DNS_TYPE_PTR);
 116
 117             if (r->interface > 0 && interface != r->interface)
 118                 return;
 119
 120             if (r->protocol != AVAHI_PROTO_UNSPEC && protocol != r->protocol)
 121                 return;
 122
 123             if (r->interface <= 0)
 124                 r->interface = interface;
 125
 126             if (r->protocol == AVAHI_PROTO_UNSPEC)
 127                 r->protocol = protocol;
 128
 129             if (!r->ptr_record) {
 130                 r->ptr_record = avahi_record_ref(record);
 131                 r->flags = flags;
 132
 133                 finish(r, AVAHI_RESOLVER_FOUND);
 134             }
 135             break;
 136
 137         case AVAHI_BROWSER_REMOVE:
 138             assert(record);
 139             assert(record->key->type == AVAHI_DNS_TYPE_PTR);
 140
 141             if (r->ptr_record && avahi_record_equal_no_ttl(record, r->ptr_record)) {
 142                 avahi_record_unref(r->ptr_record);
 143                 r->ptr_record = NULL;
 144                 r->flags = flags;
 145
 146                 /** Look for a replacement */
 147                 avahi_s_record_browser_restart(r->record_browser);
 148                 start_timeout(r);
 149             }
 150
 151             break;
 152
 153         case AVAHI_BROWSER_CACHE_EXHAUSTED:
 154         case AVAHI_BROWSER_ALL_FOR_NOW:
 155             break;
 156
 157         case AVAHI_BROWSER_FAILURE:
 158
 159             if (r->retry_with_multicast) {
 160                 r->retry_with_multicast = 0;
 161
 162                 avahi_s_record_browser_free(r->record_browser);
 163                 r->record_browser = avahi_s_record_browser_new(r->server, r->interface, r->protocol, r->key, AVAHI_LOOKUP_USE_MULTICAST, record_browser_callback, r);
 164
 165                 if (r->record_browser) {
 166                     start_timeout(r);
 167                     break;
 168                 }
 169             }
 170
 171             r->flags = flags;
 172             finish(r, AVAHI_RESOLVER_FAILURE);
 173             break;
 174     }
 175 }
 176
 177 AvahiSAddressResolver *avahi_s_address_resolver_new(
 178     AvahiServer *server,
 179     AvahiIfIndex interface,
 180     AvahiProtocol protocol,
 181     const AvahiAddress *address,
 182     AvahiLookupFlags flags,
 183     AvahiSAddressResolverCallback callback,
 184     void* userdata) {
 185
 186     AvahiSAddressResolver *r;
 187     AvahiKey *k;
 188     char n[AVAHI_DOMAIN_NAME_MAX];
 189
 190     assert(server);
 191     assert(address);
 192     assert(callback);
 193
 194     AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE);
 195     AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL);
 196     AVAHI_CHECK_VALIDITY_RETURN_NULL(server, address->proto == AVAHI_PROTO_INET || address->proto == AVAHI_PROTO_INET6, AVAHI_ERR_INVALID_PROTOCOL);
 197     AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
 198
 199     avahi_reverse_lookup_name(address, n, sizeof(n));
 200
 201     if (!(k = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR))) {
 202         avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
 203         return NULL;
 204     }
 205
 206     if (!(r = avahi_new(AvahiSAddressResolver, 1))) {
 207         avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
 208         avahi_key_unref(k);
 209         return NULL;
 210     }
 211
 212     r->server = server;
 213     r->address = *address;
 214     r->callback = callback;
 215     r->userdata = userdata;
 216     r->ptr_record = NULL;
 217     r->interface = interface;
 218     r->protocol = protocol;
 219     r->flags = 0;
 220     r->retry_with_multicast = 0;
 221     r->key = k;
 222
 223     r->record_browser = NULL;
 224     AVAHI_LLIST_PREPEND(AvahiSAddressResolver, resolver, server->address_resolvers, r);
 225
 226     r->time_event = NULL;
 227
 228     if (!(flags & (AVAHI_LOOKUP_USE_MULTICAST|AVAHI_LOOKUP_USE_WIDE_AREA))) {
 229
 230         if (!server->wide_area_lookup_engine || !avahi_wide_area_has_servers(server->wide_area_lookup_engine))
 231             flags |= AVAHI_LOOKUP_USE_MULTICAST;
 232         else {
 233             flags |= AVAHI_LOOKUP_USE_WIDE_AREA;
 234             r->retry_with_multicast = 1;
 235         }
 236     }
 237
 238     r->record_browser = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
 239
 240     if (!r->record_browser) {
 241         avahi_s_address_resolver_free(r);
 242         return NULL;
 243     }
 244
 245     start_timeout(r);
 246
 247     return r;
 248 }
 249
 250 void avahi_s_address_resolver_free(AvahiSAddressResolver *r) {
 251     assert(r);
 252
 253     AVAHI_LLIST_REMOVE(AvahiSAddressResolver, resolver, r->server->address_resolvers, r);
 254
 255     if (r->record_browser)
 256         avahi_s_record_browser_free(r->record_browser);
 257
 258     if (r->time_event)
 259         avahi_time_event_free(r->time_event);
 260
 261     if (r->ptr_record)
 262         avahi_record_unref(r->ptr_record);
 263
 264     if (r->key)
 265         avahi_key_unref(r->key);
 266
 267     avahi_free(r);
 268 }