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/timeval.h>
27 #include "avahi-common/avahi-malloc.h"
28 #include <avahi-common/error.h>
29 #include <avahi-common/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
finish(AvahiSAddressResolver * r,AvahiResolverEvent event)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
time_event_callback(AvahiTimeEvent * e,void * userdata)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
start_timeout(AvahiSAddressResolver * r)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
record_browser_callback(AvahiSRecordBrowser * rr,AvahiIfIndex interface,AvahiProtocol protocol,AvahiBrowserEvent event,AvahiRecord * record,AvahiLookupResultFlags flags,void * userdata)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
avahi_s_address_resolver_new(AvahiServer * server,AvahiIfIndex interface,AvahiProtocol protocol,const AvahiAddress * address,AvahiLookupFlags flags,AvahiSAddressResolverCallback callback,void * userdata)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
avahi_s_address_resolver_free(AvahiSAddressResolver * r)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 }
269