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
35struct 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
57static 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
77static 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
87static 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
98static 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
177AvahiSAddressResolver *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
250void 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