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 <stdlib.h>
27
28#include <avahi-common/domain.h>
29#include <avahi-common/timeval.h>
30#include <avahi-common/malloc.h>
31#include <avahi-common/error.h>
32
33#include "browse.h"
34#include "log.h"
35
36#define TIMEOUT_MSEC 5000
37
38struct AvahiSHostNameResolver {
39    AvahiServer *server;
40    char *host_name;
41
42    AvahiSRecordBrowser *record_browser_a;
43    AvahiSRecordBrowser *record_browser_aaaa;
44
45    AvahiSHostNameResolverCallback callback;
46    void* userdata;
47
48    AvahiRecord *address_record;
49    AvahiIfIndex interface;
50    AvahiProtocol protocol;
51    AvahiLookupResultFlags flags;
52
53    AvahiTimeEvent *time_event;
54
55    AVAHI_LLIST_FIELDS(AvahiSHostNameResolver, resolver);
56};
57
58static void finish(AvahiSHostNameResolver *r, AvahiResolverEvent event) {
59    assert(r);
60
61    if (r->time_event) {
62        avahi_time_event_free(r->time_event);
63        r->time_event = NULL;
64    }
65
66    switch (event) {
67        case AVAHI_RESOLVER_FOUND: {
68            AvahiAddress a;
69
70            assert(r->address_record);
71
72            switch (r->address_record->key->type) {
73                case AVAHI_DNS_TYPE_A:
74                    a.proto = AVAHI_PROTO_INET;
75                    a.data.ipv4 = r->address_record->data.a.address;
76                    break;
77
78                case AVAHI_DNS_TYPE_AAAA:
79                    a.proto = AVAHI_PROTO_INET6;
80                    a.data.ipv6 = r->address_record->data.aaaa.address;
81                    break;
82
83                default:
84                    abort();
85            }
86
87            r->callback(r, r->interface, r->protocol, AVAHI_RESOLVER_FOUND, r->address_record->key->name, &a, r->flags, r->userdata);
88            break;
89
90        }
91
92        case AVAHI_RESOLVER_FAILURE:
93
94            r->callback(r, r->interface, r->protocol, event, r->host_name, NULL, r->flags, r->userdata);
95            break;
96    }
97}
98
99static void time_event_callback(AvahiTimeEvent *e, void *userdata) {
100    AvahiSHostNameResolver *r = userdata;
101
102    assert(e);
103    assert(r);
104
105    avahi_server_set_errno(r->server, AVAHI_ERR_TIMEOUT);
106    finish(r, AVAHI_RESOLVER_FAILURE);
107}
108
109static void start_timeout(AvahiSHostNameResolver *r) {
110    struct timeval tv;
111    assert(r);
112
113    if (r->time_event)
114        return;
115
116    avahi_elapse_time(&tv, TIMEOUT_MSEC, 0);
117
118    r->time_event = avahi_time_event_new(r->server->time_event_queue, &tv, time_event_callback, r);
119}
120
121static void record_browser_callback(
122    AvahiSRecordBrowser*rr,
123    AvahiIfIndex interface,
124    AvahiProtocol protocol,
125    AvahiBrowserEvent event,
126    AvahiRecord *record,
127    AvahiLookupResultFlags flags,
128    void* userdata) {
129
130    AvahiSHostNameResolver *r = userdata;
131
132    assert(rr);
133    assert(r);
134
135
136    switch (event) {
137        case AVAHI_BROWSER_NEW:
138            assert(record);
139            assert(record->key->type == AVAHI_DNS_TYPE_A || record->key->type == AVAHI_DNS_TYPE_AAAA);
140
141            if (r->interface > 0 && interface != r->interface)
142                return;
143
144            if (r->protocol != AVAHI_PROTO_UNSPEC && protocol != r->protocol)
145                return;
146
147            if (r->interface <= 0)
148                r->interface = interface;
149
150            if (r->protocol == AVAHI_PROTO_UNSPEC)
151                r->protocol = protocol;
152
153            if (!r->address_record) {
154                r->address_record = avahi_record_ref(record);
155                r->flags = flags;
156
157                finish(r, AVAHI_RESOLVER_FOUND);
158            }
159
160            break;
161
162        case AVAHI_BROWSER_REMOVE:
163            assert(record);
164            assert(record->key->type == AVAHI_DNS_TYPE_A || record->key->type == AVAHI_DNS_TYPE_AAAA);
165
166            if (r->address_record && avahi_record_equal_no_ttl(record, r->address_record)) {
167                avahi_record_unref(r->address_record);
168                r->address_record = NULL;
169
170                r->flags = flags;
171
172
173                /** Look for a replacement */
174                if (r->record_browser_aaaa)
175                    avahi_s_record_browser_restart(r->record_browser_aaaa);
176                if (r->record_browser_a)
177                    avahi_s_record_browser_restart(r->record_browser_a);
178
179                start_timeout(r);
180            }
181
182            break;
183
184        case AVAHI_BROWSER_CACHE_EXHAUSTED:
185        case AVAHI_BROWSER_ALL_FOR_NOW:
186            /* Ignore */
187            break;
188
189        case AVAHI_BROWSER_FAILURE:
190
191            /* Stop browsers */
192
193            if (r->record_browser_aaaa)
194                avahi_s_record_browser_free(r->record_browser_aaaa);
195            if (r->record_browser_a)
196                avahi_s_record_browser_free(r->record_browser_a);
197
198            r->record_browser_a = r->record_browser_aaaa = NULL;
199            r->flags = flags;
200
201            finish(r, AVAHI_RESOLVER_FAILURE);
202            break;
203    }
204}
205
206AvahiSHostNameResolver *avahi_s_host_name_resolver_new(
207    AvahiServer *server,
208    AvahiIfIndex interface,
209    AvahiProtocol protocol,
210    const char *host_name,
211    AvahiProtocol aprotocol,
212    AvahiLookupFlags flags,
213    AvahiSHostNameResolverCallback callback,
214    void* userdata) {
215
216    AvahiSHostNameResolver *r;
217    AvahiKey *k;
218
219    assert(server);
220    assert(host_name);
221    assert(callback);
222
223    AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_IF_VALID(interface), AVAHI_ERR_INVALID_INTERFACE);
224    AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(protocol), AVAHI_ERR_INVALID_PROTOCOL);
225    AVAHI_CHECK_VALIDITY_RETURN_NULL(server, avahi_is_valid_fqdn(host_name), AVAHI_ERR_INVALID_HOST_NAME);
226    AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_PROTO_VALID(aprotocol), AVAHI_ERR_INVALID_PROTOCOL);
227    AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
228
229    if (!(r = avahi_new(AvahiSHostNameResolver, 1))) {
230        avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
231        return NULL;
232    }
233
234    r->server = server;
235    r->host_name = avahi_normalize_name_strdup(host_name);
236    r->callback = callback;
237    r->userdata = userdata;
238    r->address_record = NULL;
239    r->interface = interface;
240    r->protocol = protocol;
241    r->flags = 0;
242
243    r->record_browser_a = r->record_browser_aaaa = NULL;
244
245    r->time_event = NULL;
246
247    AVAHI_LLIST_PREPEND(AvahiSHostNameResolver, resolver, server->host_name_resolvers, r);
248
249    r->record_browser_aaaa = r->record_browser_a = NULL;
250
251    if (aprotocol == AVAHI_PROTO_INET || aprotocol == AVAHI_PROTO_UNSPEC) {
252        k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_A);
253        r->record_browser_a = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
254        avahi_key_unref(k);
255
256        if (!r->record_browser_a)
257            goto fail;
258    }
259
260    if (aprotocol == AVAHI_PROTO_INET6 || aprotocol == AVAHI_PROTO_UNSPEC) {
261        k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_AAAA);
262        r->record_browser_aaaa = avahi_s_record_browser_new(server, interface, protocol, k, flags, record_browser_callback, r);
263        avahi_key_unref(k);
264
265        if (!r->record_browser_aaaa)
266            goto fail;
267    }
268
269    assert(r->record_browser_aaaa || r->record_browser_a);
270
271    start_timeout(r);
272
273    return r;
274
275fail:
276    avahi_s_host_name_resolver_free(r);
277    return NULL;
278}
279
280void avahi_s_host_name_resolver_free(AvahiSHostNameResolver *r) {
281    assert(r);
282
283    AVAHI_LLIST_REMOVE(AvahiSHostNameResolver, resolver, r->server->host_name_resolvers, r);
284
285    if (r->record_browser_a)
286        avahi_s_record_browser_free(r->record_browser_a);
287
288    if (r->record_browser_aaaa)
289        avahi_s_record_browser_free(r->record_browser_aaaa);
290
291    if (r->time_event)
292        avahi_time_event_free(r->time_event);
293
294    if (r->address_record)
295        avahi_record_unref(r->address_record);
296
297    avahi_free(r->host_name);
298    avahi_free(r);
299}
300