FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
sapdec.c
Go to the documentation of this file.
1 /*
2  * Session Announcement Protocol (RFC 2974) demuxer
3  * Copyright (c) 2010 Martin Storsjo
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "libavutil/avassert.h"
24 #include "libavutil/avstring.h"
25 #include "libavutil/intreadwrite.h"
26 #include "network.h"
27 #include "os_support.h"
28 #include "internal.h"
29 #include "avio_internal.h"
30 #include "url.h"
31 #include "rtpdec.h"
32 #if HAVE_POLL_H
33 #include <poll.h>
34 #endif
35 
36 struct SAPState {
40  uint16_t hash;
41  char *sdp;
42  int eof;
43 };
44 
45 static int sap_probe(AVProbeData *p)
46 {
47  if (av_strstart(p->filename, "sap:", NULL))
48  return AVPROBE_SCORE_MAX;
49  return 0;
50 }
51 
53 {
54  struct SAPState *sap = s->priv_data;
55  if (sap->sdp_ctx)
57  if (sap->ann_fd)
58  ffurl_close(sap->ann_fd);
59  av_freep(&sap->sdp);
61  return 0;
62 }
63 
65 {
66  struct SAPState *sap = s->priv_data;
67  char host[1024], path[1024], url[1024];
69  int port;
70  int ret, i;
71  AVInputFormat* infmt;
72 
73  if (!ff_network_init())
74  return AVERROR(EIO);
75 
76  av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
77  path, sizeof(path), s->filename);
78  if (port < 0)
79  port = 9875;
80 
81  if (!host[0]) {
82  /* Listen for announcements on sap.mcast.net if no host was specified */
83  av_strlcpy(host, "224.2.127.254", sizeof(host));
84  }
85 
86  ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
87  port);
88  ret = ffurl_open(&sap->ann_fd, url, AVIO_FLAG_READ,
90  if (ret)
91  goto fail;
92 
93  while (1) {
94  int addr_type, auth_len;
95  int pos;
96 
97  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
98  if (ret == AVERROR(EAGAIN))
99  continue;
100  if (ret < 0)
101  goto fail;
102  recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
103  if (ret < 8) {
104  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
105  continue;
106  }
107 
108  if ((recvbuf[0] & 0xe0) != 0x20) {
109  av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
110  "received\n");
111  continue;
112  }
113 
114  if (recvbuf[0] & 0x04) {
115  av_log(s, AV_LOG_WARNING, "Received stream deletion "
116  "announcement\n");
117  continue;
118  }
119  addr_type = recvbuf[0] & 0x10;
120  auth_len = recvbuf[1];
121  sap->hash = AV_RB16(&recvbuf[2]);
122  pos = 4;
123  if (addr_type)
124  pos += 16; /* IPv6 */
125  else
126  pos += 4; /* IPv4 */
127  pos += auth_len * 4;
128  if (pos + 4 >= ret) {
129  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
130  continue;
131  }
132 #define MIME "application/sdp"
133  if (strcmp(&recvbuf[pos], MIME) == 0) {
134  pos += strlen(MIME) + 1;
135  } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
136  // Direct SDP without a mime type
137  } else {
138  av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
139  &recvbuf[pos]);
140  continue;
141  }
142 
143  sap->sdp = av_strdup(&recvbuf[pos]);
144  break;
145  }
146 
147  av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
148  ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
149  NULL, NULL);
150 
151  infmt = av_find_input_format("sdp");
152  if (!infmt)
153  goto fail;
155  if (!sap->sdp_ctx) {
156  ret = AVERROR(ENOMEM);
157  goto fail;
158  }
159  sap->sdp_ctx->max_delay = s->max_delay;
160  sap->sdp_ctx->pb = &sap->sdp_pb;
162 
163  if ((ret = ff_copy_whitelists(sap->sdp_ctx, s)) < 0)
164  goto fail;
165 
166  ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
167  if (ret < 0)
168  goto fail;
169  if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
171  for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
173  if (!st) {
174  ret = AVERROR(ENOMEM);
175  goto fail;
176  }
177  st->id = i;
179  st->time_base = sap->sdp_ctx->streams[i]->time_base;
180  }
181 
182  return 0;
183 
184 fail:
185  sap_read_close(s);
186  return ret;
187 }
188 
190 {
191  struct SAPState *sap = s->priv_data;
192  int fd = ffurl_get_file_handle(sap->ann_fd);
193  int n, ret;
194  struct pollfd p = {fd, POLLIN, 0};
196 
197  if (sap->eof)
198  return AVERROR_EOF;
199 
200  while (1) {
201  n = poll(&p, 1, 0);
202  if (n <= 0 || !(p.revents & POLLIN))
203  break;
204  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
205  if (ret >= 8) {
206  uint16_t hash = AV_RB16(&recvbuf[2]);
207  /* Should ideally check the source IP address, too */
208  if (recvbuf[0] & 0x04 && hash == sap->hash) {
209  /* Stream deletion */
210  sap->eof = 1;
211  return AVERROR_EOF;
212  }
213  }
214  }
215  ret = av_read_frame(sap->sdp_ctx, pkt);
216  if (ret < 0)
217  return ret;
218  if (s->ctx_flags & AVFMTCTX_NOHEADER) {
219  while (sap->sdp_ctx->nb_streams > s->nb_streams) {
220  int i = s->nb_streams;
222  if (!st) {
223  av_free_packet(pkt);
224  return AVERROR(ENOMEM);
225  }
226  st->id = i;
228  st->time_base = sap->sdp_ctx->streams[i]->time_base;
229  }
230  }
231  return ret;
232 }
233 
235  .name = "sap",
236  .long_name = NULL_IF_CONFIG_SMALL("SAP input"),
237  .priv_data_size = sizeof(struct SAPState),
238  .read_probe = sap_probe,
239  .read_header = sap_read_header,
240  .read_packet = sap_fetch_packet,
241  .read_close = sap_read_close,
242  .flags = AVFMT_NOFILE,
243 };
void av_url_split(char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url)
Split a URL string into components.
Definition: utils.c:3963
#define NULL
Definition: coverity.c:32
static int sap_read_close(AVFormatContext *s)
Definition: sapdec.c:52
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:111
void av_free_packet(AVPacket *pkt)
Free a packet.
Definition: avpacket.c:280
#define RTP_MAX_PACKET_LENGTH
Definition: rtpdec.h:36
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1523
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
const char * filename
Definition: avformat.h:449
int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:405
AVInputFormat ff_sap_demuxer
Definition: sapdec.c:234
#define AVIO_FLAG_READ
read-only
Definition: avio.h:485
void ff_network_close(void)
Definition: network.c:102
AVIOContext sdp_pb
Definition: sapdec.c:39
static AVPacket pkt
int ctx_flags
Flags signalling stream properties.
Definition: avformat.h:1322
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src)
Copy the settings of the source AVCodecContext into the destination AVCodecContext.
Definition: options.c:182
Format I/O context.
Definition: avformat.h:1273
uint8_t
int ff_network_init(void)
Definition: network.c:55
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1232
miscellaneous OS support macros and functions.
int id
Format-specific stream ID.
Definition: avformat.h:849
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:3749
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1341
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
Definition: options.c:111
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:192
#define av_log(a,...)
uint16_t hash
Definition: sapdec.c:40
static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sapdec.c:189
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
simple assert() macros that are a bit more flexible than ISO C assert().
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:83
#define fail()
Definition: checkasm.h:57
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1329
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:160
char filename[1024]
input or output filename
Definition: avformat.h:1349
URLContext * ann_fd
Definition: sapdec.c:37
AVFormatContext * sdp_ctx
Definition: sapdec.c:38
int n
Definition: avisynth_c.h:547
int ffurl_get_file_handle(URLContext *h)
Return the file descriptor associated with this URL.
Definition: avio.c:571
char * sdp
Definition: sapdec.c:41
Stream structure.
Definition: avformat.h:842
int ff_url_join(char *str, int size, const char *proto, const char *authorization, const char *hostname, int port, const char *fmt,...)
Definition: url.c:36
static struct AVHashContext * hash
Definition: ffprobe.c:216
char * av_strdup(const char *s)
Duplicate the string s.
Definition: mem.c:267
AVIOContext * pb
I/O context.
Definition: avformat.h:1315
Definition: url.h:39
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1478
static int sap_read_header(AVFormatContext *s)
Definition: sapdec.c:64
static int sap_probe(AVProbeData *p)
Definition: sapdec.c:45
int ff_copy_whitelists(AVFormatContext *dst, AVFormatContext *src)
Copies the whilelists from one context to the other.
Definition: utils.c:140
int ffurl_close(URLContext *h)
Definition: avio.c:412
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
Main libavformat public API header.
#define MIME
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:465
int ffio_init_context(AVIOContext *s, unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Definition: aviobuf.c:72
int ffurl_open(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:292
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:3721
void * priv_data
Format private data.
Definition: avformat.h:1301
int eof
Definition: sapdec.c:42
#define av_freep(p)
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:628
unbuffered private I/O API
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:884
This structure stores compressed data.
Definition: avcodec.h:1400
int ffurl_read(URLContext *h, unsigned char *buf, int size)
Read up to size bytes from the resource accessed by h, and store the read bytes in buf...
Definition: avio.c:353