FFmpeg
 All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
rtpproto.c
Go to the documentation of this file.
1 /*
2  * RTP network protocol
3  * Copyright (c) 2002 Fabrice Bellard
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 /**
23  * @file
24  * RTP protocol
25  */
26 
27 #include "libavutil/parseutils.h"
28 #include "libavutil/avstring.h"
29 #include "avformat.h"
30 #include "avio_internal.h"
31 #include "rtpdec.h"
32 #include "url.h"
33 
34 #include <stdarg.h>
35 #include "internal.h"
36 #include "network.h"
37 #include "os_support.h"
38 #include <fcntl.h>
39 #if HAVE_POLL_H
40 #include <sys/poll.h>
41 #endif
42 
43 typedef struct RTPContext {
46 } RTPContext;
47 
48 /**
49  * If no filename is given to av_open_input_file because you want to
50  * get the local port first, then you must call this function to set
51  * the remote server address.
52  *
53  * @param h media file context
54  * @param uri of the remote server
55  * @return zero if no error.
56  */
57 
58 int ff_rtp_set_remote_url(URLContext *h, const char *uri)
59 {
60  RTPContext *s = h->priv_data;
61  char hostname[256];
62  int port;
63 
64  char buf[1024];
65  char path[1024];
66 
67  av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,
68  path, sizeof(path), uri);
69 
70  ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, port, "%s", path);
72 
73  ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, port + 1, "%s", path);
75  return 0;
76 }
77 
78 
79 /**
80  * add option to url of the form:
81  * "http://host:port/path?option1=val1&option2=val2...
82  */
83 
84 static av_printf_format(3, 4) void url_add_option(char *buf, int buf_size, const char *fmt, ...)
85 {
86  char buf1[1024];
87  va_list ap;
88 
89  va_start(ap, fmt);
90  if (strchr(buf, '?'))
91  av_strlcat(buf, "&", buf_size);
92  else
93  av_strlcat(buf, "?", buf_size);
94  vsnprintf(buf1, sizeof(buf1), fmt, ap);
95  av_strlcat(buf, buf1, buf_size);
96  va_end(ap);
97 }
98 
99 static void build_udp_url(char *buf, int buf_size,
100  const char *hostname, int port,
101  int local_port, int ttl,
102  int max_packet_size, int connect)
103 {
104  ff_url_join(buf, buf_size, "udp", NULL, hostname, port, NULL);
105  if (local_port >= 0)
106  url_add_option(buf, buf_size, "localport=%d", local_port);
107  if (ttl >= 0)
108  url_add_option(buf, buf_size, "ttl=%d", ttl);
109  if (max_packet_size >=0)
110  url_add_option(buf, buf_size, "pkt_size=%d", max_packet_size);
111  if (connect)
112  url_add_option(buf, buf_size, "connect=1");
113  url_add_option(buf, buf_size, "fifo_size=0");
114 }
115 
116 /**
117  * url syntax: rtp://host:port[?option=val...]
118  * option: 'ttl=n' : set the ttl value (for multicast only)
119  * 'rtcpport=n' : set the remote rtcp port to n
120  * 'localrtpport=n' : set the local rtp port to n
121  * 'localrtcpport=n' : set the local rtcp port to n
122  * 'pkt_size=n' : set max packet size
123  * 'connect=0/1' : do a connect() on the UDP socket
124  * deprecated option:
125  * 'localport=n' : set the local port to n
126  *
127  * if rtcpport isn't set the rtcp port will be the rtp port + 1
128  * if local rtp port isn't set any available port will be used for the local
129  * rtp and rtcp ports
130  * if the local rtcp port is not set it will be the local rtp port + 1
131  */
132 
133 static int rtp_open(URLContext *h, const char *uri, int flags)
134 {
135  RTPContext *s = h->priv_data;
136  int rtp_port, rtcp_port,
137  ttl, connect,
138  local_rtp_port, local_rtcp_port, max_packet_size;
139  char hostname[256];
140  char buf[1024];
141  char path[1024];
142  const char *p;
143 
144  av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,
145  path, sizeof(path), uri);
146  /* extract parameters */
147  ttl = -1;
148  rtcp_port = rtp_port+1;
149  local_rtp_port = -1;
150  local_rtcp_port = -1;
151  max_packet_size = -1;
152  connect = 0;
153 
154  p = strchr(uri, '?');
155  if (p) {
156  if (av_find_info_tag(buf, sizeof(buf), "ttl", p)) {
157  ttl = strtol(buf, NULL, 10);
158  }
159  if (av_find_info_tag(buf, sizeof(buf), "rtcpport", p)) {
160  rtcp_port = strtol(buf, NULL, 10);
161  }
162  if (av_find_info_tag(buf, sizeof(buf), "localport", p)) {
163  local_rtp_port = strtol(buf, NULL, 10);
164  }
165  if (av_find_info_tag(buf, sizeof(buf), "localrtpport", p)) {
166  local_rtp_port = strtol(buf, NULL, 10);
167  }
168  if (av_find_info_tag(buf, sizeof(buf), "localrtcpport", p)) {
169  local_rtcp_port = strtol(buf, NULL, 10);
170  }
171  if (av_find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
172  max_packet_size = strtol(buf, NULL, 10);
173  }
174  if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
175  connect = strtol(buf, NULL, 10);
176  }
177  }
178 
179  build_udp_url(buf, sizeof(buf),
180  hostname, rtp_port, local_rtp_port, ttl, max_packet_size,
181  connect);
182  if (ffurl_open(&s->rtp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
183  goto fail;
184  if (local_rtp_port>=0 && local_rtcp_port<0)
185  local_rtcp_port = ff_udp_get_local_port(s->rtp_hd) + 1;
186 
187  build_udp_url(buf, sizeof(buf),
188  hostname, rtcp_port, local_rtcp_port, ttl, max_packet_size,
189  connect);
190  if (ffurl_open(&s->rtcp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
191  goto fail;
192 
193  /* just to ease handle access. XXX: need to suppress direct handle
194  access */
197 
199  h->is_streamed = 1;
200  return 0;
201 
202  fail:
203  if (s->rtp_hd)
204  ffurl_close(s->rtp_hd);
205  if (s->rtcp_hd)
206  ffurl_close(s->rtcp_hd);
207  return AVERROR(EIO);
208 }
209 
210 static int rtp_read(URLContext *h, uint8_t *buf, int size)
211 {
212  RTPContext *s = h->priv_data;
213  struct sockaddr_storage from;
214  socklen_t from_len;
215  int len, n;
216  struct pollfd p[2] = {{s->rtp_fd, POLLIN, 0}, {s->rtcp_fd, POLLIN, 0}};
217 
218  for(;;) {
220  return AVERROR_EXIT;
221  /* build fdset to listen to RTP and RTCP packets */
222  n = poll(p, 2, 100);
223  if (n > 0) {
224  /* first try RTCP */
225  if (p[1].revents & POLLIN) {
226  from_len = sizeof(from);
227  len = recvfrom (s->rtcp_fd, buf, size, 0,
228  (struct sockaddr *)&from, &from_len);
229  if (len < 0) {
230  if (ff_neterrno() == AVERROR(EAGAIN) ||
231  ff_neterrno() == AVERROR(EINTR))
232  continue;
233  return AVERROR(EIO);
234  }
235  break;
236  }
237  /* then RTP */
238  if (p[0].revents & POLLIN) {
239  from_len = sizeof(from);
240  len = recvfrom (s->rtp_fd, buf, size, 0,
241  (struct sockaddr *)&from, &from_len);
242  if (len < 0) {
243  if (ff_neterrno() == AVERROR(EAGAIN) ||
244  ff_neterrno() == AVERROR(EINTR))
245  continue;
246  return AVERROR(EIO);
247  }
248  break;
249  }
250  } else if (n < 0) {
251  if (ff_neterrno() == AVERROR(EINTR))
252  continue;
253  return AVERROR(EIO);
254  }
255  }
256  return len;
257 }
258 
259 static int rtp_write(URLContext *h, const uint8_t *buf, int size)
260 {
261  RTPContext *s = h->priv_data;
262  int ret;
263  URLContext *hd;
264 
265  if (RTP_PT_IS_RTCP(buf[1])) {
266  /* RTCP payload type */
267  hd = s->rtcp_hd;
268  } else {
269  /* RTP payload type */
270  hd = s->rtp_hd;
271  }
272 
273  ret = ffurl_write(hd, buf, size);
274  return ret;
275 }
276 
277 static int rtp_close(URLContext *h)
278 {
279  RTPContext *s = h->priv_data;
280 
281  ffurl_close(s->rtp_hd);
282  ffurl_close(s->rtcp_hd);
283  return 0;
284 }
285 
286 /**
287  * Return the local rtp port used by the RTP connection
288  * @param h media file context
289  * @return the local port number
290  */
291 
293 {
294  RTPContext *s = h->priv_data;
295  return ff_udp_get_local_port(s->rtp_hd);
296 }
297 
298 /**
299  * Return the local rtcp port used by the RTP connection
300  * @param h media file context
301  * @return the local port number
302  */
303 
305 {
306  RTPContext *s = h->priv_data;
307  return ff_udp_get_local_port(s->rtcp_hd);
308 }
309 
311 {
312  RTPContext *s = h->priv_data;
313  return s->rtp_fd;
314 }
315 
316 static int rtp_get_multi_file_handle(URLContext *h, int **handles,
317  int *numhandles)
318 {
319  RTPContext *s = h->priv_data;
320  int *hs = *handles = av_malloc(sizeof(**handles) * 2);
321  if (!hs)
322  return AVERROR(ENOMEM);
323  hs[0] = s->rtp_fd;
324  hs[1] = s->rtcp_fd;
325  *numhandles = 2;
326  return 0;
327 }
328 
330  .name = "rtp",
331  .url_open = rtp_open,
332  .url_read = rtp_read,
333  .url_write = rtp_write,
334  .url_close = rtp_close,
335  .url_get_file_handle = rtp_get_file_handle,
336  .url_get_multi_file_handle = rtp_get_multi_file_handle,
337  .priv_data_size = sizeof(RTPContext),
339 };