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