1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Session Announcement Protocol (RFC 2974) demuxer
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "network.h"
#include "os_support.h"
#include "internal.h"
#include "avio_internal.h"
#include "url.h"
#if HAVE_POLL_H
#include <poll.h>
#endif
#include <sys/time.h>
struct SAPState {
URLContext *ann_fd;
AVFormatContext *sdp_ctx;
AVIOContext sdp_pb;
uint16_t hash;
char *sdp;
int eof;
};
static int sap_probe(AVProbeData *p)
{
if (av_strstart(p->filename, "sap:", NULL))
return AVPROBE_SCORE_MAX;
return 0;
}
static int sap_read_close(AVFormatContext *s)
{
struct SAPState *sap = s->priv_data;
if (sap->sdp_ctx)
av_close_input_file(sap->sdp_ctx);
if (sap->ann_fd)
ffurl_close(sap->ann_fd);
av_freep(&sap->sdp);
ff_network_close();
return 0;
}
static int sap_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
struct SAPState *sap = s->priv_data;
char host[1024], path[1024], url[1024];
uint8_t recvbuf[1500];
int port;
int ret, i;
AVInputFormat* infmt;
if (!ff_network_init())
return AVERROR(EIO);
av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
path, sizeof(path), s->filename);
if (port < 0)
port = 9875;
if (!host[0]) {
/* Listen for announcements on sap.mcast.net if no host was specified */
av_strlcpy(host, "224.2.127.254", sizeof(host));
}
ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
port);
ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ, &s->interrupt_callback);
if (ret)
goto fail;
while (1) {
int addr_type, auth_len;
int pos;
ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
if (ret == AVERROR(EAGAIN))
continue;
if (ret < 0)
goto fail;
recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
if (ret < 8) {
av_log(s, AV_LOG_WARNING, "Received too short packet\n");
continue;
}
if ((recvbuf[0] & 0xe0) != 0x20) {
av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
"received\n");
continue;
}
if (recvbuf[0] & 0x04) {
av_log(s, AV_LOG_WARNING, "Received stream deletion "
"announcement\n");
continue;
}
addr_type = recvbuf[0] & 0x10;
auth_len = recvbuf[1];
sap->hash = AV_RB16(&recvbuf[2]);
pos = 4;
if (addr_type)
pos += 16; /* IPv6 */
else
pos += 4; /* IPv4 */
pos += auth_len * 4;
if (pos + 4 >= ret) {
av_log(s, AV_LOG_WARNING, "Received too short packet\n");
continue;
}
#define MIME "application/sdp"
if (strcmp(&recvbuf[pos], MIME) == 0) {
pos += strlen(MIME) + 1;
} else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
// Direct SDP without a mime type
} else {
av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
&recvbuf[pos]);
continue;
}
sap->sdp = av_strdup(&recvbuf[pos]);
break;
}
av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
NULL, NULL);
infmt = av_find_input_format("sdp");
if (!infmt)
goto fail;
sap->sdp_ctx = avformat_alloc_context();
if (!sap->sdp_ctx) {
ret = AVERROR(ENOMEM);
goto fail;
}
sap->sdp_ctx->max_delay = s->max_delay;
sap->sdp_ctx->pb = &sap->sdp_pb;
ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
if (ret < 0)
goto fail;
if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
s->ctx_flags |= AVFMTCTX_NOHEADER;
for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
AVStream *st = avformat_new_stream(s, NULL);
if (!st) {
ret = AVERROR(ENOMEM);
goto fail;
}
st->id = i;
avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
st->time_base = sap->sdp_ctx->streams[i]->time_base;
}
return 0;
fail:
sap_read_close(s);
return ret;
}
static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
{
struct SAPState *sap = s->priv_data;
int fd = ffurl_get_file_handle(sap->ann_fd);
int n, ret;
struct pollfd p = {fd, POLLIN, 0};
uint8_t recvbuf[1500];
if (sap->eof)
return AVERROR_EOF;
while (1) {
n = poll(&p, 1, 0);
if (n <= 0 || !(p.revents & POLLIN))
break;
ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
if (ret >= 8) {
uint16_t hash = AV_RB16(&recvbuf[2]);
/* Should ideally check the source IP address, too */
if (recvbuf[0] & 0x04 && hash == sap->hash) {
/* Stream deletion */
sap->eof = 1;
return AVERROR_EOF;
}
}
}
ret = av_read_frame(sap->sdp_ctx, pkt);
if (ret < 0)
return ret;
if (s->ctx_flags & AVFMTCTX_NOHEADER) {
while (sap->sdp_ctx->nb_streams > s->nb_streams) {
int i = s->nb_streams;
AVStream *st = avformat_new_stream(s, NULL);
if (!st) {
av_free_packet(pkt);
return AVERROR(ENOMEM);
}
st->id = i;
avcodec_copy_context(st->codec, sap->sdp_ctx->streams[i]->codec);
st->time_base = sap->sdp_ctx->streams[i]->time_base;
}
}
return ret;
}
AVInputFormat ff_sap_demuxer = {
.name = "sap",
.long_name = NULL_IF_CONFIG_SMALL("SAP input format"),
.priv_data_size = sizeof(struct SAPState),
.read_probe = sap_probe,
.read_header = sap_read_header,
.read_packet = sap_fetch_packet,
.read_close = sap_read_close,
.flags = AVFMT_NOFILE,
};
|
