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-common/domain.h>
27 #include <avahi-common/timeval.h>
28 #include "avahi-common/avahi-malloc.h"
29 #include <avahi-common/error.h>
30
31 #include "browse.h"
32 #include "log.h"
33
34 #define TIMEOUT_MSEC 5000
35
36 struct AvahiSHostNameResolver {
37 AvahiServer *server;
38 char *host_name;
39
40 AvahiSRecordBrowser *record_browser_a;
41 AvahiSRecordBrowser *record_browser_aaaa;
42
43 AvahiSHostNameResolverCallback callback;
44 void* userdata;
45
46 AvahiRecord *address_record;
47 AvahiIfIndex interface;
48 AvahiProtocol protocol;
49 AvahiLookupResultFlags flags;
50
51 AvahiTimeEvent *time_event;
52
53 AVAHI_LLIST_FIELDS(AvahiSHostNameResolver, resolver);
54 };
55
finish(AvahiSHostNameResolver * r,AvahiResolverEvent event)56 static void finish(AvahiSHostNameResolver *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_FOUND: {
66 AvahiAddress a;
67
68 assert(r->address_record);
69
70 switch (r->address_record->key->type) {
71 case AVAHI_DNS_TYPE_A:
72 a.proto = AVAHI_PROTO_INET;
73 a.data.ipv4 = r->address_record->data.a.address;
74 break;
75
76 case AVAHI_DNS_TYPE_AAAA:
77 a.proto = AVAHI_PROTO_INET6;
78 a.data.ipv6 = r->address_record->data.aaaa.address;
79 break;
80
81 default:
82 abort();
83 }
84
85 r->callback(r, r->interface, r->protocol, AVAHI_RESOLVER_FOUND, r->address_record->key->name, &a, r->flags, r->userdata);
86 break;
87
88 }
89
90 case AVAHI_RESOLVER_FAILURE:
91
92 r->callback(r, r->interface, r->protocol, event, r->host_name, NULL, r->flags, r->userdata);
93 break;
94 }
95 }
96
time_event_callback(AvahiTimeEvent * e,void * userdata)97 static void time_event_callback(AvahiTimeEvent *e, void *userdata) {
98 AvahiSHostNameResolver *r = userdata;
99
100 assert(e);
101 assert(r);
102
103 avahi_server_set_errno(r->server, AVAHI_ERR_TIMEOUT);
104 finish(r, AVAHI_RESOLVER_FAILURE);
105 }
106
start_timeout(AvahiSHostNameResolver * r)107 static void start_timeout(AvahiSHostNameResolver *r) {
108 struct timeval tv;
109 assert(r);
110
111 if (r->time_event)
112 return;
113
114 avahi_elapse_time(&tv, TIMEOUT_MSEC, 0);
115
116 r->time_event = avahi_time_event_new(r->server->time_event_queue, &tv, time_event_callback, r);
117 }
118
record_browser_callback(AvahiSRecordBrowser * rr,AvahiIfIndex interface,AvahiProtocol protocol,AvahiBrowserEvent event,AvahiRecord * record,AvahiLookupResultFlags flags,void * userdata)119 static void record_browser_callback(
120 AvahiSRecordBrowser*rr,
121 AvahiIfIndex interface,
122 AvahiProtocol protocol,
123 AvahiBrowserEvent event,
124 AvahiRecord *record,
125 AvahiLookupResultFlags flags,
126 void* userdata) {
127
128 AvahiSHostNameResolver *r = userdata;
129
130 assert(rr);
131 assert(r);
132
133
134 switch (event) {
135 case AVAHI_BROWSER_NEW:
136 assert(record);
137 assert(record->key->type == AVAHI_DNS_TYPE_A || record->key->type == AVAHI_DNS_TYPE_AAAA);
138
139 if (r->interface > 0 && interface != r->interface)
140 return;
141
142 if (r->protocol != AVAHI_PROTO_UNSPEC && protocol != r->protocol)
143 return;
144
145 if (r->interface <= 0)
146 r->interface = interface;
147
148 if (r->protocol == AVAHI_PROTO_UNSPEC)
149 r->protocol = protocol;
150
151 if (!r->address_record) {
152 r->address_record = avahi_record_ref(record);
153 r->flags = flags;
154
155 finish(r, AVAHI_RESOLVER_FOUND);
156 }
157
158 break;
159
160 case AVAHI_BROWSER_REMOVE:
161 assert(record);
162 assert(record->key->type == AVAHI_DNS_TYPE_A || record->key->type == AVAHI_DNS_TYPE_AAAA);
163
164 if (r->address_record && avahi_record_equal_no_ttl(record, r->address_record)) {
165 avahi_record_unref(r->address_record);
166 r->address_record = NULL;
167
168 r->flags = flags;
169
170
171 /** Look for a replacement */
172 if (r->record_browser_aaaa)
173 avahi_s_record_browser_restart(r->record_browser_aaaa);
174 if (r->record_browser_a)
175 avahi_s_record_browser_restart(r->record_browser_a);
176
177 start_timeout(r);
178 }
179
180 break;
181
182 case AVAHI_BROWSER_CACHE_EXHAUSTED:
183 case AVAHI_BROWSER_ALL_FOR_NOW:
184 /* Ignore */
185 break;
186
187 case AVAHI_BROWSER_FAILURE:
188
189 /* Stop browsers */
190
191 if (r->record_browser_aaaa)
192 avahi_s_record_browser_free(r->record_browser_aaaa);
193 if (r->record_browser_a)
194 avahi_s_record_browser_free(r->record_browser_a);
195
196 r->record_browser_a = r->record_browser_aaaa = NULL;
197 r->flags = flags;
198
199 finish(r, AVAHI_RESOLVER_FAILURE);
200 break;
201 }
202 }
203
avahi_s_host_name_resolver_new(AvahiServer * server,AvahiIfIndex interface,AvahiProtocol protocol,const char * host_name,AvahiProtocol aprotocol,AvahiLookupFlags flags,AvahiSHostNameResolverCallback callback,void * userdata)204 AvahiSHostNameResolver *avahi_s_host_name_resolver_new(
205 AvahiServer *server,
206 AvahiIfIndex interface,
207 AvahiProtocol protocol,
208 const char *host_name,
209 AvahiProtocol aprotocol,
210 AvahiLookupFlags flags,
211 AvahiSHostNameResolverCallback callback,
212 void* userdata) {
213
214 AvahiSHostNameResolver *r;
215 AvahiKey *k;
216
217 assert(server);
218 assert(host_name);
219 assert(callback);
220
221 AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE);
222 AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL);
223 AVAHI_CHECK_VALIDITY_RETURN_NULL(server, avahi_is_valid_fqdn(host_name), AVAHI_ERR_INVALID_HOST_NAME);
224 AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(aprotocol), AVAHI_ERR_INVALID_PROTOCOL);
225 AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
226
227 if (!(r = avahi_new(AvahiSHostNameResolver, 1))) {
228 avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
229 return NULL;
230 }
231
232 r->server = server;
233 r->host_name = avahi_normalize_name_strdup(host_name);
234 r->callback = callback;
235 r->userdata = userdata;
236 r->address_record = NULL;
237 r->interface = interface;
238 r->protocol = protocol;
239 r->flags = 0;
240
241 r->record_browser_a = r->record_browser_aaaa = NULL;
242
243 r->time_event = NULL;
244
245 AVAHI_LLIST_PREPEND(AvahiSHostNameResolver, resolver, server->host_name_resolvers, r);
246
247 r->record_browser_aaaa = r->record_browser_a = NULL;
248
249 if (aprotocol == AVAHI_PROTO_INET || aprotocol == AVAHI_PROTO_UNSPEC) {
250 k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_A);
251 r->record_browser_a = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
252 avahi_key_unref(k);
253
254 if (!r->record_browser_a)
255 goto fail;
256 }
257
258 if (aprotocol == AVAHI_PROTO_INET6 || aprotocol == AVAHI_PROTO_UNSPEC) {
259 k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_AAAA);
260 r->record_browser_aaaa = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
261 avahi_key_unref(k);
262
263 if (!r->record_browser_aaaa)
264 goto fail;
265 }
266
267 assert(r->record_browser_aaaa || r->record_browser_a);
268
269 start_timeout(r);
270
271 return r;
272
273 fail:
274 avahi_s_host_name_resolver_free(r);
275 return NULL;
276 }
277
avahi_s_host_name_resolver_free(AvahiSHostNameResolver * r)278 void avahi_s_host_name_resolver_free(AvahiSHostNameResolver *r) {
279 assert(r);
280
281 AVAHI_LLIST_REMOVE(AvahiSHostNameResolver, resolver, r->server->host_name_resolvers, r);
282
283 if (r->record_browser_a)
284 avahi_s_record_browser_free(r->record_browser_a);
285
286 if (r->record_browser_aaaa)
287 avahi_s_record_browser_free(r->record_browser_aaaa);
288
289 if (r->time_event)
290 avahi_time_event_free(r->time_event);
291
292 if (r->address_record)
293 avahi_record_unref(r->address_record);
294
295 avahi_free(r->host_name);
296 avahi_free(r);
297 }
298