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/malloc.h>
29#include <avahi-common/error.h>
30
31#include "browse.h"
32#include "log.h"
33
34#define TIMEOUT_MSEC 5000
35
36struct 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
56static 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
97static 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
107static 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
119static 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
204AvahiSHostNameResolver *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_domain_name(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_LOOKUP_USE_LLMNR), 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
273fail:
274    avahi_s_host_name_resolver_free(r);
275    return NULL;
276}
277
278void 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