git.meshlink.io Git - catta/blob - avahi-core/resolve-address.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 <avahi-common/timeval.h>
  27 #include <avahi-common/malloc.h>
  28 #include <avahi-common/error.h>
  29
  30 #include "browse.h"
  31
  32 #define TIMEOUT_MSEC 5000
  33
  34 struct AvahiSAddressResolver {
  35     AvahiServer *server;
  36     AvahiAddress address;
  37
  38     AvahiSRecordBrowser *record_browser;
  39
  40     AvahiSAddressResolverCallback callback;
  41     void* userdata;
  42
  43     AvahiRecord *ptr_record;
  44     AvahiIfIndex interface;
  45     AvahiProtocol protocol;
  46     AvahiLookupResultFlags flags;
  47
  48     int retry_with_multicast;
  49     AvahiKey *key;
  50
  51     AvahiTimeEvent *time_event;
  52
  53     AVAHI_LLIST_FIELDS(AvahiSAddressResolver, resolver);
  54 };
  55
  56 static void finish(AvahiSAddressResolver *r, AvahiResolverEvent event) {
  57     assert(r);
  58
  59     if (r->time_event) {
  60         avahi_time_event_free(r->time_event);
  61         r->time_event = NULL;
  62     }
  63
  64     switch (event) {
  65         case AVAHI_RESOLVER_NOT_FOUND:
  66         case AVAHI_RESOLVER_TIMEOUT:
  67         case AVAHI_RESOLVER_FAILURE:
  68             r->callback(r, r->interface, r->protocol, event, &r->address, NULL, r->flags, r->userdata);
  69             break;
  70
  71         case AVAHI_RESOLVER_FOUND:
  72             assert(r->ptr_record);
  73             r->callback(r, r->interface, r->protocol, event, &r->address, r->ptr_record->data.ptr.name, r->flags, r->userdata);
  74             break;
  75     }
  76 }
  77
  78 static void time_event_callback(AvahiTimeEvent *e, void *userdata) {
  79     AvahiSAddressResolver *r = userdata;
  80
  81     assert(e);
  82     assert(r);
  83
  84     finish(r, AVAHI_RESOLVER_TIMEOUT);
  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
 113     switch (event) {
 114         case AVAHI_BROWSER_NEW:
 115             assert(record);
 116             assert(record->key->type == AVAHI_DNS_TYPE_PTR);
 117
 118             if (r->interface > 0 && interface != r->interface)
 119                 return;
 120
 121             if (r->protocol != AVAHI_PROTO_UNSPEC && protocol != r->protocol)
 122                 return;
 123
 124             if (r->interface <= 0)
 125                 r->interface = interface;
 126
 127             if (r->protocol == AVAHI_PROTO_UNSPEC)
 128                 r->protocol = protocol;
 129
 130             if (!r->ptr_record) {
 131                 r->ptr_record = avahi_record_ref(record);
 132                 r->flags = flags;
 133
 134                 finish(r, AVAHI_RESOLVER_FOUND);
 135             }
 136             break;
 137
 138         case AVAHI_BROWSER_REMOVE:
 139             assert(record);
 140             assert(record->key->type == AVAHI_DNS_TYPE_PTR);
 141
 142             if (r->ptr_record && avahi_record_equal_no_ttl(record, r->ptr_record)) {
 143                 avahi_record_unref(r->ptr_record);
 144                 r->ptr_record = NULL;
 145                 r->flags = flags;
 146
 147                 /** Look for a replacement */
 148                 avahi_s_record_browser_restart(r->record_browser);
 149                 start_timeout(r);
 150             }
 151
 152             break;
 153
 154         case AVAHI_BROWSER_CACHE_EXHAUSTED:
 155         case AVAHI_BROWSER_ALL_FOR_NOW:
 156             break;
 157
 158         case AVAHI_BROWSER_NOT_FOUND:
 159
 160             if (r->retry_with_multicast) {
 161                 r->retry_with_multicast = 0;
 162
 163                 avahi_s_record_browser_free(r->record_browser);
 164                 r->record_browser = avahi_s_record_browser_new(r->server, r->interface, r->protocol, r->key, AVAHI_LOOKUP_USE_MULTICAST, record_browser_callback, r);
 165
 166                 if (r->record_browser) {
 167                     start_timeout(r);
 168                     break;
 169                 }
 170             }
 171
 172             /* Fallthrough */
 173
 174         case AVAHI_BROWSER_FAILURE:
 175             r->flags = flags;
 176             finish(r, event == AVAHI_BROWSER_NOT_FOUND ? AVAHI_RESOLVER_NOT_FOUND : AVAHI_RESOLVER_FAILURE);
 177
 178     }
 179 }
 180
 181 AvahiSAddressResolver *avahi_s_address_resolver_new(
 182     AvahiServer *server,
 183     AvahiIfIndex interface,
 184     AvahiProtocol protocol,
 185     const AvahiAddress *address,
 186     AvahiLookupFlags flags,
 187     AvahiSAddressResolverCallback callback,
 188     void* userdata) {
 189
 190     AvahiSAddressResolver *r;
 191     AvahiKey *k;
 192     char *n;
 193
 194     assert(server);
 195     assert(address);
 196     assert(callback);
 197
 198     assert(address->proto == AVAHI_PROTO_INET || address->proto == AVAHI_PROTO_INET6);
 199
 200     if (!AVAHI_IF_VALID(interface)) {
 201         avahi_server_set_errno(server, AVAHI_ERR_INVALID_INTERFACE);
 202         return NULL;
 203     }
 204
 205     if (!AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST)) {
 206         avahi_server_set_errno(server, AVAHI_ERR_INVALID_FLAGS);
 207         return NULL;
 208     }
 209
 210     if (address->proto == AVAHI_PROTO_INET)
 211         n = avahi_reverse_lookup_name_ipv4(&address->data.ipv4);
 212     else
 213         n = avahi_reverse_lookup_name_ipv6_arpa(&address->data.ipv6);
 214
 215     if (!n) {
 216         avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
 217         return NULL;
 218     }
 219
 220     k = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR);
 221     avahi_free(n);
 222
 223     if (!k) {
 224         avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
 225         return NULL;
 226     }
 227
 228     if (!(r = avahi_new(AvahiSAddressResolver, 1))) {
 229         avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
 230         avahi_key_unref(k);
 231         return NULL;
 232     }
 233
 234     r->server = server;
 235     r->address = *address;
 236     r->callback = callback;
 237     r->userdata = userdata;
 238     r->ptr_record = NULL;
 239     r->interface = interface;
 240     r->protocol = protocol;
 241     r->flags = 0;
 242     r->retry_with_multicast = 0;
 243     r->key = k;
 244
 245     r->record_browser = NULL;
 246     AVAHI_LLIST_PREPEND(AvahiSAddressResolver, resolver, server->address_resolvers, r);
 247
 248     r->time_event = NULL;
 249
 250     if (!(flags & (AVAHI_LOOKUP_USE_MULTICAST|AVAHI_LOOKUP_USE_WIDE_AREA))) {
 251
 252         if (!server->wide_area_lookup_engine || !avahi_wide_area_has_servers(server->wide_area_lookup_engine))
 253             flags |= AVAHI_LOOKUP_USE_MULTICAST;
 254         else {
 255             flags |= AVAHI_LOOKUP_USE_WIDE_AREA;
 256             r->retry_with_multicast = 1;
 257         }
 258     }
 259
 260     r->record_browser = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
 261
 262     if (!r->record_browser) {
 263         avahi_s_address_resolver_free(r);
 264         return NULL;
 265     }
 266
 267     start_timeout(r);
 268
 269     return r;
 270 }
 271
 272 void avahi_s_address_resolver_free(AvahiSAddressResolver *r) {
 273     assert(r);
 274
 275     AVAHI_LLIST_REMOVE(AvahiSAddressResolver, resolver, r->server->address_resolvers, r);
 276
 277     if (r->record_browser)
 278         avahi_s_record_browser_free(r->record_browser);
 279
 280     if (r->time_event)
 281         avahi_time_event_free(r->time_event);
 282
 283     if (r->ptr_record)
 284         avahi_record_unref(r->ptr_record);
 285
 286     if (r->key)
 287         avahi_key_unref(r->key);
 288
 289     avahi_free(r);
 290 }