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sapdec.c
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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_whitelist(&sap->ann_fd, url, AVIO_FLAG_READ,
91  if (ret)
92  goto fail;
93 
94  while (1) {
95  int addr_type, auth_len;
96  int pos;
97 
98  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
99  if (ret == AVERROR(EAGAIN))
100  continue;
101  if (ret < 0)
102  goto fail;
103  recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
104  if (ret < 8) {
105  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
106  continue;
107  }
108 
109  if ((recvbuf[0] & 0xe0) != 0x20) {
110  av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
111  "received\n");
112  continue;
113  }
114 
115  if (recvbuf[0] & 0x04) {
116  av_log(s, AV_LOG_WARNING, "Received stream deletion "
117  "announcement\n");
118  continue;
119  }
120  addr_type = recvbuf[0] & 0x10;
121  auth_len = recvbuf[1];
122  sap->hash = AV_RB16(&recvbuf[2]);
123  pos = 4;
124  if (addr_type)
125  pos += 16; /* IPv6 */
126  else
127  pos += 4; /* IPv4 */
128  pos += auth_len * 4;
129  if (pos + 4 >= ret) {
130  av_log(s, AV_LOG_WARNING, "Received too short packet\n");
131  continue;
132  }
133 #define MIME "application/sdp"
134  if (strcmp(&recvbuf[pos], MIME) == 0) {
135  pos += strlen(MIME) + 1;
136  } else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
137  // Direct SDP without a mime type
138  } else {
139  av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
140  &recvbuf[pos]);
141  continue;
142  }
143 
144  sap->sdp = av_strdup(&recvbuf[pos]);
145  break;
146  }
147 
148  av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
149  ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
150  NULL, NULL);
151 
152  infmt = av_find_input_format("sdp");
153  if (!infmt)
154  goto fail;
156  if (!sap->sdp_ctx) {
157  ret = AVERROR(ENOMEM);
158  goto fail;
159  }
160  sap->sdp_ctx->max_delay = s->max_delay;
161  sap->sdp_ctx->pb = &sap->sdp_pb;
163 
164  if ((ret = ff_copy_whiteblacklists(sap->sdp_ctx, s)) < 0)
165  goto fail;
166 
167  ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
168  if (ret < 0)
169  goto fail;
170  if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
172  for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
174  if (!st) {
175  ret = AVERROR(ENOMEM);
176  goto fail;
177  }
178  st->id = i;
180  st->time_base = sap->sdp_ctx->streams[i]->time_base;
181  }
182 
183  return 0;
184 
185 fail:
186  sap_read_close(s);
187  return ret;
188 }
189 
191 {
192  struct SAPState *sap = s->priv_data;
193  int fd = ffurl_get_file_handle(sap->ann_fd);
194  int n, ret;
195  struct pollfd p = {fd, POLLIN, 0};
197 
198  if (sap->eof)
199  return AVERROR_EOF;
200 
201  while (1) {
202  n = poll(&p, 1, 0);
203  if (n <= 0 || !(p.revents & POLLIN))
204  break;
205  ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
206  if (ret >= 8) {
207  uint16_t hash = AV_RB16(&recvbuf[2]);
208  /* Should ideally check the source IP address, too */
209  if (recvbuf[0] & 0x04 && hash == sap->hash) {
210  /* Stream deletion */
211  sap->eof = 1;
212  return AVERROR_EOF;
213  }
214  }
215  }
216  ret = av_read_frame(sap->sdp_ctx, pkt);
217  if (ret < 0)
218  return ret;
219  if (s->ctx_flags & AVFMTCTX_NOHEADER) {
220  while (sap->sdp_ctx->nb_streams > s->nb_streams) {
221  int i = s->nb_streams;
223  if (!st) {
224  av_packet_unref(pkt);
225  return AVERROR(ENOMEM);
226  }
227  st->id = i;
229  st->time_base = sap->sdp_ctx->streams[i]->time_base;
230  }
231  }
232  return ret;
233 }
234 
236  .name = "sap",
237  .long_name = NULL_IF_CONFIG_SMALL("SAP input"),
238  .priv_data_size = sizeof(struct SAPState),
239  .read_probe = sap_probe,
240  .read_header = sap_read_header,
241  .read_packet = sap_fetch_packet,
242  .read_close = sap_read_close,
243  .flags = AVFMT_NOFILE,
244 };
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:4387
#define NULL
Definition: coverity.c:32
static int sap_read_close(AVFormatContext *s)
Definition: sapdec.c:52
const char * s
Definition: avisynth_c.h:768
Bytestream IO Context.
Definition: avio.h:147
int ffurl_open_whitelist(URLContext **puc, const char *filename, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options, const char *whitelist, const char *blacklist, URLContext *parent)
Create an URLContext for accessing to the resource indicated by url, and open it. ...
Definition: avio.c:309
#define RTP_MAX_PACKET_LENGTH
Definition: rtpdec.h:36
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1579
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
const char * filename
Definition: avformat.h:462
int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src)
Copies the whilelists from one context to the other.
Definition: utils.c:145
AVInputFormat ff_sap_demuxer
Definition: sapdec.c:235
#define AVIO_FLAG_READ
read-only
Definition: avio.h:606
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:1376
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
Format I/O context.
Definition: avformat.h:1327
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:1280
miscellaneous OS support macros and functions.
int id
Format-specific stream ID.
Definition: avformat.h:885
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4140
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1395
AVFormatContext * avformat_alloc_context(void)
Allocate an AVFormatContext.
Definition: options.c:132
char * protocol_whitelist
',' separated list of allowed protocols.
Definition: avformat.h:1863
#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
uint8_t hash[HASH_SIZE]
Definition: movenc.c:57
static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sapdec.c:190
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src)
Copy the contents of src to dst.
Definition: utils.c:4065
#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:176
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:82
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1383
AVInputFormat * av_find_input_format(const char *short_name)
Find AVInputFormat based on the short name of the input format.
Definition: format.c:164
char filename[1024]
input or output filename
Definition: avformat.h:1403
URLContext * ann_fd
Definition: sapdec.c:37
AVFormatContext * sdp_ctx
Definition: sapdec.c:38
int n
Definition: avisynth_c.h:684
int ffurl_get_file_handle(URLContext *h)
Return the file descriptor associated with this URL.
Definition: avio.c:626
char * sdp
Definition: sapdec.c:41
Stream structure.
Definition: avformat.h:878
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
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:267
AVIOContext * pb
I/O context.
Definition: avformat.h:1369
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:563
Definition: url.h:38
This structure contains the data a format has to probe a file.
Definition: avformat.h:461
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1647
static int sap_read_header(AVFormatContext *s)
Definition: sapdec.c:64
static int sap_probe(AVProbeData *p)
Definition: sapdec.c:45
int ffurl_close(URLContext *h)
Definition: avio.c:467
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:473
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:478
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:81
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:4112
void * priv_data
Format private data.
Definition: avformat.h:1355
int avformat_open_input(AVFormatContext **ps, const char *url, AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:474
int eof
Definition: sapdec.c:42
char * protocol_blacklist
',' separated list of disallowed protocols.
Definition: avformat.h:1898
#define av_freep(p)
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:662
unbuffered private I/O API
AVCodecParameters * codecpar
Definition: avformat.h:1230
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:915
This structure stores compressed data.
Definition: avcodec.h:1567
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:407