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rtpproto.c
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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 "rtp.h"
32 #include "rtpproto.h"
33 #include "url.h"
34 
35 #include <stdarg.h>
36 #include "internal.h"
37 #include "network.h"
38 #include "os_support.h"
39 #include <fcntl.h>
40 #if HAVE_POLL_H
41 #include <sys/poll.h>
42 #endif
43 
44 typedef struct RTPContext {
49  struct sockaddr_storage last_rtp_source, last_rtcp_source;
51 } RTPContext;
52 
53 /**
54  * If no filename is given to av_open_input_file because you want to
55  * get the local port first, then you must call this function to set
56  * the remote server address.
57  *
58  * @param h media file context
59  * @param uri of the remote server
60  * @return zero if no error.
61  */
62 
63 int ff_rtp_set_remote_url(URLContext *h, const char *uri)
64 {
65  RTPContext *s = h->priv_data;
66  char hostname[256];
67  int port, rtcp_port;
68  const char *p;
69 
70  char buf[1024];
71  char path[1024];
72 
73  av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &port,
74  path, sizeof(path), uri);
75  rtcp_port = port + 1;
76 
77  p = strchr(uri, '?');
78  if (p) {
79  if (av_find_info_tag(buf, sizeof(buf), "rtcpport", p)) {
80  rtcp_port = strtol(buf, NULL, 10);
81  }
82  }
83 
84  ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, port, "%s", path);
86 
87  ff_url_join(buf, sizeof(buf), "udp", NULL, hostname, rtcp_port, "%s", path);
89  return 0;
90 }
91 
92 static struct addrinfo* rtp_resolve_host(const char *hostname, int port,
93  int type, int family, int flags)
94 {
95  struct addrinfo hints = { 0 }, *res = 0;
96  int error;
97  char service[16];
98 
99  snprintf(service, sizeof(service), "%d", port);
100  hints.ai_socktype = type;
101  hints.ai_family = family;
102  hints.ai_flags = flags;
103  if ((error = getaddrinfo(hostname, service, &hints, &res))) {
104  res = NULL;
105  av_log(NULL, AV_LOG_ERROR, "rtp_resolve_host: %s\n", gai_strerror(error));
106  }
107 
108  return res;
109 }
110 
111 static int compare_addr(const struct sockaddr_storage *a,
112  const struct sockaddr_storage *b)
113 {
114  if (a->ss_family != b->ss_family)
115  return 1;
116  if (a->ss_family == AF_INET) {
117  return (((const struct sockaddr_in *)a)->sin_addr.s_addr !=
118  ((const struct sockaddr_in *)b)->sin_addr.s_addr);
119  }
120 
121 #if HAVE_STRUCT_SOCKADDR_IN6
122  if (a->ss_family == AF_INET6) {
123  const uint8_t *s6_addr_a = ((const struct sockaddr_in6 *)a)->sin6_addr.s6_addr;
124  const uint8_t *s6_addr_b = ((const struct sockaddr_in6 *)b)->sin6_addr.s6_addr;
125  return memcmp(s6_addr_a, s6_addr_b, 16);
126  }
127 #endif
128  return 1;
129 }
130 
131 static int get_port(const struct sockaddr_storage *ss)
132 {
133  if (ss->ss_family == AF_INET)
134  return ntohs(((const struct sockaddr_in *)ss)->sin_port);
135 #if HAVE_STRUCT_SOCKADDR_IN6
136  if (ss->ss_family == AF_INET6)
137  return ntohs(((const struct sockaddr_in6 *)ss)->sin6_port);
138 #endif
139  return 0;
140 }
141 
142 static void set_port(struct sockaddr_storage *ss, int port)
143 {
144  if (ss->ss_family == AF_INET)
145  ((struct sockaddr_in *)ss)->sin_port = htons(port);
146 #if HAVE_STRUCT_SOCKADDR_IN6
147  else if (ss->ss_family == AF_INET6)
148  ((struct sockaddr_in6 *)ss)->sin6_port = htons(port);
149 #endif
150 }
151 
152 static int rtp_check_source_lists(RTPContext *s, struct sockaddr_storage *source_addr_ptr)
153 {
154  int i;
155  if (s->nb_ssm_exclude_addrs) {
156  for (i = 0; i < s->nb_ssm_exclude_addrs; i++) {
157  if (!compare_addr(source_addr_ptr, s->ssm_exclude_addrs[i]))
158  return 1;
159  }
160  }
161  if (s->nb_ssm_include_addrs) {
162  for (i = 0; i < s->nb_ssm_include_addrs; i++) {
163  if (!compare_addr(source_addr_ptr, s->ssm_include_addrs[i]))
164  return 0;
165  }
166  return 1;
167  }
168  return 0;
169 }
170 
171 /**
172  * add option to url of the form:
173  * "http://host:port/path?option1=val1&option2=val2...
174  */
175 
176 static av_printf_format(3, 4) void url_add_option(char *buf, int buf_size, const char *fmt, ...)
177 {
178  char buf1[1024];
179  va_list ap;
180 
181  va_start(ap, fmt);
182  if (strchr(buf, '?'))
183  av_strlcat(buf, "&", buf_size);
184  else
185  av_strlcat(buf, "?", buf_size);
186  vsnprintf(buf1, sizeof(buf1), fmt, ap);
187  av_strlcat(buf, buf1, buf_size);
188  va_end(ap);
189 }
190 
191 static void build_udp_url(char *buf, int buf_size,
192  const char *hostname, int port,
193  int local_port, int ttl,
194  int max_packet_size, int connect,
195  const char *include_sources,
196  const char *exclude_sources)
197 {
198  ff_url_join(buf, buf_size, "udp", NULL, hostname, port, NULL);
199  if (local_port >= 0)
200  url_add_option(buf, buf_size, "localport=%d", local_port);
201  if (ttl >= 0)
202  url_add_option(buf, buf_size, "ttl=%d", ttl);
203  if (max_packet_size >=0)
204  url_add_option(buf, buf_size, "pkt_size=%d", max_packet_size);
205  if (connect)
206  url_add_option(buf, buf_size, "connect=1");
207  url_add_option(buf, buf_size, "fifo_size=0");
208  if (include_sources && include_sources[0])
209  url_add_option(buf, buf_size, "sources=%s", include_sources);
210  if (exclude_sources && exclude_sources[0])
211  url_add_option(buf, buf_size, "block=%s", exclude_sources);
212 }
213 
214 static void rtp_parse_addr_list(URLContext *h, char *buf,
215  struct sockaddr_storage ***address_list_ptr,
216  int *address_list_size_ptr)
217 {
218  struct addrinfo *ai = NULL;
219  struct sockaddr_storage *source_addr;
220  char tmp = '\0', *p = buf, *next;
221 
222  /* Resolve all of the IPs */
223 
224  while (p && p[0]) {
225  next = strchr(p, ',');
226 
227  if (next) {
228  tmp = *next;
229  *next = '\0';
230  }
231 
232  ai = rtp_resolve_host(p, 0, SOCK_DGRAM, AF_UNSPEC, 0);
233  if (ai) {
234  source_addr = av_mallocz(sizeof(struct sockaddr_storage));
235  if (!source_addr) {
236  freeaddrinfo(ai);
237  break;
238  }
239 
240  memcpy(source_addr, ai->ai_addr, ai->ai_addrlen);
241  freeaddrinfo(ai);
242  dynarray_add(address_list_ptr, address_list_size_ptr, source_addr);
243  } else {
244  av_log(h, AV_LOG_WARNING, "Unable to resolve %s\n", p);
245  }
246 
247  if (next) {
248  *next = tmp;
249  p = next + 1;
250  } else {
251  p = NULL;
252  }
253  }
254 }
255 
256 /**
257  * url syntax: rtp://host:port[?option=val...]
258  * option: 'ttl=n' : set the ttl value (for multicast only)
259  * 'rtcpport=n' : set the remote rtcp port to n
260  * 'localrtpport=n' : set the local rtp port to n
261  * 'localrtcpport=n' : set the local rtcp port to n
262  * 'pkt_size=n' : set max packet size
263  * 'connect=0/1' : do a connect() on the UDP socket
264  * 'sources=ip[,ip]' : list allowed source IP addresses
265  * 'block=ip[,ip]' : list disallowed source IP addresses
266  * 'write_to_source=0/1' : send packets to the source address of the latest received packet
267  * deprecated option:
268  * 'localport=n' : set the local port to n
269  *
270  * if rtcpport isn't set the rtcp port will be the rtp port + 1
271  * if local rtp port isn't set any available port will be used for the local
272  * rtp and rtcp ports
273  * if the local rtcp port is not set it will be the local rtp port + 1
274  */
275 
276 static int rtp_open(URLContext *h, const char *uri, int flags)
277 {
278  RTPContext *s = h->priv_data;
279  int rtp_port, rtcp_port,
280  ttl, connect,
281  local_rtp_port, local_rtcp_port, max_packet_size;
282  char hostname[256], include_sources[1024] = "", exclude_sources[1024] = "";
283  char buf[1024];
284  char path[1024];
285  const char *p;
286  int i, max_retry_count = 3;
287 
288  av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,
289  path, sizeof(path), uri);
290  /* extract parameters */
291  ttl = -1;
292  rtcp_port = rtp_port+1;
293  local_rtp_port = -1;
294  local_rtcp_port = -1;
295  max_packet_size = -1;
296  connect = 0;
297 
298  p = strchr(uri, '?');
299  if (p) {
300  if (av_find_info_tag(buf, sizeof(buf), "ttl", p)) {
301  ttl = strtol(buf, NULL, 10);
302  }
303  if (av_find_info_tag(buf, sizeof(buf), "rtcpport", p)) {
304  rtcp_port = strtol(buf, NULL, 10);
305  }
306  if (av_find_info_tag(buf, sizeof(buf), "localport", p)) {
307  local_rtp_port = strtol(buf, NULL, 10);
308  }
309  if (av_find_info_tag(buf, sizeof(buf), "localrtpport", p)) {
310  local_rtp_port = strtol(buf, NULL, 10);
311  }
312  if (av_find_info_tag(buf, sizeof(buf), "localrtcpport", p)) {
313  local_rtcp_port = strtol(buf, NULL, 10);
314  }
315  if (av_find_info_tag(buf, sizeof(buf), "pkt_size", p)) {
316  max_packet_size = strtol(buf, NULL, 10);
317  }
318  if (av_find_info_tag(buf, sizeof(buf), "connect", p)) {
319  connect = strtol(buf, NULL, 10);
320  }
321  if (av_find_info_tag(buf, sizeof(buf), "write_to_source", p)) {
322  s->write_to_source = strtol(buf, NULL, 10);
323  }
324  if (av_find_info_tag(buf, sizeof(buf), "sources", p)) {
325  av_strlcpy(include_sources, buf, sizeof(include_sources));
327  }
328  if (av_find_info_tag(buf, sizeof(buf), "block", p)) {
329  av_strlcpy(exclude_sources, buf, sizeof(exclude_sources));
331  }
332  }
333 
334  for (i = 0;i < max_retry_count;i++) {
335  build_udp_url(buf, sizeof(buf),
336  hostname, rtp_port, local_rtp_port, ttl, max_packet_size,
337  connect, include_sources, exclude_sources);
338  if (ffurl_open(&s->rtp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
339  goto fail;
340  local_rtp_port = ff_udp_get_local_port(s->rtp_hd);
341  if(local_rtp_port == 65535) {
342  local_rtp_port = -1;
343  continue;
344  }
345  if (local_rtcp_port<0) {
346  local_rtcp_port = local_rtp_port + 1;
347  build_udp_url(buf, sizeof(buf),
348  hostname, rtcp_port, local_rtcp_port, ttl, max_packet_size,
349  connect, include_sources, exclude_sources);
350  if (ffurl_open(&s->rtcp_hd, buf, flags, &h->interrupt_callback, NULL) < 0) {
351  local_rtp_port = local_rtcp_port = -1;
352  continue;
353  }
354  break;
355  }
356  build_udp_url(buf, sizeof(buf),
357  hostname, rtcp_port, local_rtcp_port, ttl, max_packet_size,
358  connect, include_sources, exclude_sources);
359  if (ffurl_open(&s->rtcp_hd, buf, flags, &h->interrupt_callback, NULL) < 0)
360  goto fail;
361  break;
362  }
363 
364  /* just to ease handle access. XXX: need to suppress direct handle
365  access */
368 
370  h->is_streamed = 1;
371  return 0;
372 
373  fail:
374  if (s->rtp_hd)
375  ffurl_close(s->rtp_hd);
376  if (s->rtcp_hd)
377  ffurl_close(s->rtcp_hd);
378  return AVERROR(EIO);
379 }
380 
381 static int rtp_read(URLContext *h, uint8_t *buf, int size)
382 {
383  RTPContext *s = h->priv_data;
384  int len, n, i;
385  struct pollfd p[2] = {{s->rtp_fd, POLLIN, 0}, {s->rtcp_fd, POLLIN, 0}};
386  int poll_delay = h->flags & AVIO_FLAG_NONBLOCK ? 0 : 100;
387  struct sockaddr_storage *addrs[2] = { &s->last_rtp_source, &s->last_rtcp_source };
388  socklen_t *addr_lens[2] = { &s->last_rtp_source_len, &s->last_rtcp_source_len };
389 
390  for(;;) {
392  return AVERROR_EXIT;
393  n = poll(p, 2, poll_delay);
394  if (n > 0) {
395  /* first try RTCP, then RTP */
396  for (i = 1; i >= 0; i--) {
397  if (!(p[i].revents & POLLIN))
398  continue;
399  *addr_lens[i] = sizeof(*addrs[i]);
400  len = recvfrom(p[i].fd, buf, size, 0,
401  (struct sockaddr *)addrs[i], addr_lens[i]);
402  if (len < 0) {
403  if (ff_neterrno() == AVERROR(EAGAIN) ||
404  ff_neterrno() == AVERROR(EINTR))
405  continue;
406  return AVERROR(EIO);
407  }
408  if (rtp_check_source_lists(s, addrs[i]))
409  continue;
410  return len;
411  }
412  } else if (n < 0) {
413  if (ff_neterrno() == AVERROR(EINTR))
414  continue;
415  return AVERROR(EIO);
416  }
417  if (h->flags & AVIO_FLAG_NONBLOCK)
418  return AVERROR(EAGAIN);
419  }
420  return len;
421 }
422 
423 static int rtp_write(URLContext *h, const uint8_t *buf, int size)
424 {
425  RTPContext *s = h->priv_data;
426  int ret;
427  URLContext *hd;
428 
429  if (size < 2)
430  return AVERROR(EINVAL);
431 
432  if (s->write_to_source) {
433  int fd;
434  struct sockaddr_storage *source, temp_source;
435  socklen_t *source_len, temp_len;
436  if (!s->last_rtp_source.ss_family && !s->last_rtcp_source.ss_family) {
437  av_log(h, AV_LOG_ERROR,
438  "Unable to send packet to source, no packets received yet\n");
439  // Intentionally not returning an error here
440  return size;
441  }
442 
443  if (RTP_PT_IS_RTCP(buf[1])) {
444  fd = s->rtcp_fd;
445  source = &s->last_rtcp_source;
446  source_len = &s->last_rtcp_source_len;
447  } else {
448  fd = s->rtp_fd;
449  source = &s->last_rtp_source;
450  source_len = &s->last_rtp_source_len;
451  }
452  if (!source->ss_family) {
453  source = &temp_source;
454  source_len = &temp_len;
455  if (RTP_PT_IS_RTCP(buf[1])) {
456  temp_source = s->last_rtp_source;
457  temp_len = s->last_rtp_source_len;
458  set_port(source, get_port(source) + 1);
459  av_log(h, AV_LOG_INFO,
460  "Not received any RTCP packets yet, inferring peer port "
461  "from the RTP port\n");
462  } else {
463  temp_source = s->last_rtcp_source;
464  temp_len = s->last_rtcp_source_len;
465  set_port(source, get_port(source) - 1);
466  av_log(h, AV_LOG_INFO,
467  "Not received any RTP packets yet, inferring peer port "
468  "from the RTCP port\n");
469  }
470  }
471 
472  if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
473  ret = ff_network_wait_fd(fd, 1);
474  if (ret < 0)
475  return ret;
476  }
477  ret = sendto(fd, buf, size, 0, (struct sockaddr *) source,
478  *source_len);
479 
480  return ret < 0 ? ff_neterrno() : ret;
481  }
482 
483  if (RTP_PT_IS_RTCP(buf[1])) {
484  /* RTCP payload type */
485  hd = s->rtcp_hd;
486  } else {
487  /* RTP payload type */
488  hd = s->rtp_hd;
489  }
490 
491  ret = ffurl_write(hd, buf, size);
492  return ret;
493 }
494 
495 static int rtp_close(URLContext *h)
496 {
497  RTPContext *s = h->priv_data;
498  int i;
499 
500  for (i = 0; i < s->nb_ssm_include_addrs; i++)
501  av_free(s->ssm_include_addrs[i]);
503  for (i = 0; i < s->nb_ssm_exclude_addrs; i++)
504  av_free(s->ssm_exclude_addrs[i]);
506 
507  ffurl_close(s->rtp_hd);
508  ffurl_close(s->rtcp_hd);
509  return 0;
510 }
511 
512 /**
513  * Return the local rtp port used by the RTP connection
514  * @param h media file context
515  * @return the local port number
516  */
517 
519 {
520  RTPContext *s = h->priv_data;
521  return ff_udp_get_local_port(s->rtp_hd);
522 }
523 
524 /**
525  * Return the local rtcp port used by the RTP connection
526  * @param h media file context
527  * @return the local port number
528  */
529 
531 {
532  RTPContext *s = h->priv_data;
533  return ff_udp_get_local_port(s->rtcp_hd);
534 }
535 
537 {
538  RTPContext *s = h->priv_data;
539  return s->rtp_fd;
540 }
541 
542 static int rtp_get_multi_file_handle(URLContext *h, int **handles,
543  int *numhandles)
544 {
545  RTPContext *s = h->priv_data;
546  int *hs = *handles = av_malloc(sizeof(**handles) * 2);
547  if (!hs)
548  return AVERROR(ENOMEM);
549  hs[0] = s->rtp_fd;
550  hs[1] = s->rtcp_fd;
551  *numhandles = 2;
552  return 0;
553 }
554 
556  .name = "rtp",
557  .url_open = rtp_open,
558  .url_read = rtp_read,
559  .url_write = rtp_write,
560  .url_close = rtp_close,
561  .url_get_file_handle = rtp_get_file_handle,
562  .url_get_multi_file_handle = rtp_get_multi_file_handle,
563  .priv_data_size = sizeof(RTPContext),
565 };