FFmpeg
sctp.c
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1 /*
2  * SCTP protocol
3  * Copyright (c) 2012 Luca Barbato
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  *
25  * sctp url_protocol
26  *
27  * url syntax: sctp://host:port[?option=val...]
28  * option: 'listen' : listen for an incoming connection
29  * 'max_streams=n' : set the maximum number of streams
30  * 'reuse=1' : enable reusing the socket [TBD]
31  *
32  * by setting the maximum number of streams the protocol will use the
33  * first two bytes of the incoming/outgoing buffer to store the
34  * stream number of the packet being read/written.
35  * @see sctp_read
36  * @see sctp_write
37  */
38 
39 
40 #include <netinet/in.h>
41 #include <netinet/sctp.h>
42 
43 #include "config.h"
44 
45 #if HAVE_POLL_H
46 #include <poll.h>
47 #endif
48 
49 #include "libavutil/intreadwrite.h"
50 #include "libavutil/parseutils.h"
51 #include "libavutil/opt.h"
52 #include "avformat.h"
53 #include "internal.h"
54 #include "network.h"
55 #include "os_support.h"
56 #include "url.h"
57 
58 /*
59  * The sctp_recvmsg and sctp_sendmsg functions are part of the user
60  * library that offers support for the SCTP kernel Implementation.
61  * To avoid build-time clashes the functions sport an ff_-prefix here.
62  * The main purpose of this code is to provide the SCTP Socket API
63  * mappings for user applications to interface with SCTP in the kernel.
64  *
65  * This implementation is based on the Socket API Extensions for SCTP
66  * defined in <draft-ietf-tsvwg-sctpsocket-10.txt>
67  *
68  * Copyright (c) 2003 International Business Machines, Corp.
69  *
70  * Written or modified by:
71  * Ryan Layer <rmlayer@us.ibm.com>
72  */
73 
74 static int ff_sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
75  socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo,
76  int *msg_flags)
77 {
78  int recvb;
79  struct iovec iov;
80  char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
81  struct msghdr inmsg = { 0 };
82  struct cmsghdr *cmsg = NULL;
83 
84  iov.iov_base = msg;
85  iov.iov_len = len;
86 
87  inmsg.msg_name = from;
88  inmsg.msg_namelen = fromlen ? *fromlen : 0;
89  inmsg.msg_iov = &iov;
90  inmsg.msg_iovlen = 1;
91  inmsg.msg_control = incmsg;
92  inmsg.msg_controllen = sizeof(incmsg);
93 
94  if ((recvb = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0)) < 0)
95  return recvb;
96 
97  if (fromlen)
98  *fromlen = inmsg.msg_namelen;
99  if (msg_flags)
100  *msg_flags = inmsg.msg_flags;
101 
102  for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg;
103  cmsg = CMSG_NXTHDR(&inmsg, cmsg)) {
104  if ((IPPROTO_SCTP == cmsg->cmsg_level) &&
105  (SCTP_SNDRCV == cmsg->cmsg_type))
106  break;
107  }
108 
109  /* Copy sinfo. */
110  if (cmsg)
111  memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo));
112 
113  return recvb;
114 }
115 
116 static int ff_sctp_send(int s, const void *msg, size_t len,
117  const struct sctp_sndrcvinfo *sinfo, int flags)
118 {
119  struct msghdr outmsg = { 0 };
120  struct iovec iov;
121 
122  outmsg.msg_name = NULL;
123  outmsg.msg_namelen = 0;
124  outmsg.msg_iov = &iov;
125  iov.iov_base = (void*)msg;
126  iov.iov_len = len;
127  outmsg.msg_iovlen = 1;
128  outmsg.msg_controllen = 0;
129 
130  if (sinfo) {
131  char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
132  struct cmsghdr *cmsg;
133 
134  outmsg.msg_control = outcmsg;
135  outmsg.msg_controllen = sizeof(outcmsg);
136  outmsg.msg_flags = 0;
137 
138  cmsg = CMSG_FIRSTHDR(&outmsg);
139  cmsg->cmsg_level = IPPROTO_SCTP;
140  cmsg->cmsg_type = SCTP_SNDRCV;
141  cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
142 
143  outmsg.msg_controllen = cmsg->cmsg_len;
144  memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo));
145  }
146 
147  return sendmsg(s, &outmsg, flags | MSG_NOSIGNAL);
148 }
149 
150 typedef struct SCTPContext {
151  const AVClass *class;
152  int fd;
153  int listen;
154  int timeout;
158 } SCTPContext;
159 
160 #define OFFSET(x) offsetof(SCTPContext, x)
161 #define D AV_OPT_FLAG_DECODING_PARAM
162 #define E AV_OPT_FLAG_ENCODING_PARAM
163 static const AVOption options[] = {
164  { "listen", "Listen for incoming connections", OFFSET(listen), AV_OPT_TYPE_BOOL,{ .i64 = 0 }, 0, 1, .flags = D|E },
165  { "timeout", "Connection timeout (in milliseconds)", OFFSET(timeout), AV_OPT_TYPE_INT, { .i64 = 10000 }, INT_MIN, INT_MAX, .flags = D|E },
166  { "listen_timeout", "Bind timeout (in milliseconds)", OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX, .flags = D|E },
167  { "max_streams", "Max stream to allocate", OFFSET(max_streams), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT16_MAX, .flags = D|E },
168  { NULL }
169 };
170 
171 static const AVClass sctp_class = {
172  .class_name = "sctp",
173  .item_name = av_default_item_name,
174  .option = options,
175  .version = LIBAVUTIL_VERSION_INT,
176 };
177 
178 static int sctp_open(URLContext *h, const char *uri, int flags)
179 {
180  struct addrinfo *ai, *cur_ai;
181  struct addrinfo hints = { 0 };
182  struct sctp_event_subscribe event = { 0 };
183  struct sctp_initmsg initparams = { 0 };
184  int port;
185  int fd = -1;
186  SCTPContext *s = h->priv_data;
187  const char *p;
188  char buf[256];
189  int ret;
190  char hostname[1024], proto[1024], path[1024];
191  char portstr[10];
192 
193  av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),
194  &port, path, sizeof(path), uri);
195  if (strcmp(proto, "sctp"))
196  return AVERROR(EINVAL);
197  if (port <= 0 || port >= 65536) {
198  av_log(s, AV_LOG_ERROR, "Port missing in uri\n");
199  return AVERROR(EINVAL);
200  }
201 
202  p = strchr(uri, '?');
203  if (p) {
204  if (av_find_info_tag(buf, sizeof(buf), "listen", p))
205  s->listen = 1;
206  if (av_find_info_tag(buf, sizeof(buf), "max_streams", p))
207  s->max_streams = strtol(buf, NULL, 10);
208  }
209 
210  hints.ai_family = AF_UNSPEC;
211  hints.ai_socktype = SOCK_STREAM;
212  snprintf(portstr, sizeof(portstr), "%d", port);
213  ret = getaddrinfo(hostname, portstr, &hints, &ai);
214  if (ret) {
215  av_log(h, AV_LOG_ERROR, "Failed to resolve hostname %s: %s\n",
216  hostname, gai_strerror(ret));
217  return AVERROR(EIO);
218  }
219 
220  cur_ai = ai;
221 
222 restart:
223  fd = ff_socket(cur_ai->ai_family, SOCK_STREAM, IPPROTO_SCTP);
224  if (fd < 0) {
225  ret = ff_neterrno();
226  goto fail;
227  }
228 
229  if (s->listen) {
230  if ((fd = ff_listen_bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
231  s->listen_timeout, h)) < 0) {
232  ret = fd;
233  goto fail1;
234  }
235  } else {
236  if ((ret = ff_listen_connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
237  s->timeout, h, !!cur_ai->ai_next)) < 0) {
238 
239  if (ret == AVERROR_EXIT)
240  goto fail1;
241  else
242  goto fail;
243  }
244  }
245 
246  event.sctp_data_io_event = 1;
247  /* TODO: Subscribe to more event types and handle them */
248 
249  if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event,
250  sizeof(event)) != 0) {
252  "SCTP ERROR: Unable to subscribe to events\n");
253  goto fail1;
254  }
255 
256  if (s->max_streams) {
257  initparams.sinit_max_instreams = s->max_streams;
258  initparams.sinit_num_ostreams = s->max_streams;
259  if (setsockopt(fd, IPPROTO_SCTP, SCTP_INITMSG, &initparams,
260  sizeof(initparams)) < 0) {
262  "SCTP ERROR: Unable to initialize socket max streams %d\n",
263  s->max_streams);
264  ret = ff_neterrno();
265  goto fail1;
266  }
267  }
268 
269  h->priv_data = s;
270  h->is_streamed = 1;
271  s->fd = fd;
272  freeaddrinfo(ai);
273  return 0;
274 
275 fail:
276  if (cur_ai->ai_next) {
277  /* Retry with the next sockaddr */
278  cur_ai = cur_ai->ai_next;
279  if (fd >= 0)
280  closesocket(fd);
281  ret = 0;
282  goto restart;
283  }
284 fail1:
285  ret = AVERROR(EIO);
286  freeaddrinfo(ai);
287  return ret;
288 }
289 
290 static int sctp_wait_fd(int fd, int write)
291 {
292  int ev = write ? POLLOUT : POLLIN;
293  struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };
294  int ret;
295 
296  ret = poll(&p, 1, 100);
297  return ret < 0 ? ff_neterrno() : p.revents & ev ? 0 : AVERROR(EAGAIN);
298 }
299 
300 static int sctp_read(URLContext *h, uint8_t *buf, int size)
301 {
302  SCTPContext *s = h->priv_data;
303  int ret;
304 
305  if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
306  ret = sctp_wait_fd(s->fd, 0);
307  if (ret < 0)
308  return ret;
309  }
310 
311  if (s->max_streams) {
312  /*StreamId is introduced as a 2byte code into the stream*/
313  struct sctp_sndrcvinfo info = { 0 };
314  ret = ff_sctp_recvmsg(s->fd, buf + 2, size - 2, NULL, 0, &info, 0);
315  AV_WB16(buf, info.sinfo_stream);
316  ret = ret < 0 ? ret : ret + 2;
317  } else
318  ret = recv(s->fd, buf, size, 0);
319 
320  return ret < 0 ? ff_neterrno() : ret;
321 }
322 
323 static int sctp_write(URLContext *h, const uint8_t *buf, int size)
324 {
325  SCTPContext *s = h->priv_data;
326  int ret;
327 
328  if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
329  ret = sctp_wait_fd(s->fd, 1);
330  if (ret < 0)
331  return ret;
332  }
333 
334  if (s->max_streams) {
335  /*StreamId is introduced as a 2byte code into the stream*/
336  struct sctp_sndrcvinfo info = { 0 };
337  info.sinfo_stream = AV_RB16(buf);
338  if (info.sinfo_stream > s->max_streams) {
339  av_log(h, AV_LOG_ERROR, "bad input data\n");
340  return AVERROR_BUG;
341  }
342  ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);
343  } else
344  ret = send(s->fd, buf, size, MSG_NOSIGNAL);
345 
346  return ret < 0 ? ff_neterrno() : ret;
347 }
348 
349 static int sctp_close(URLContext *h)
350 {
351  SCTPContext *s = h->priv_data;
352  closesocket(s->fd);
353  return 0;
354 }
355 
357 {
358  SCTPContext *s = h->priv_data;
359  return s->fd;
360 }
361 
363  .name = "sctp",
364  .url_open = sctp_open,
365  .url_read = sctp_read,
366  .url_write = sctp_write,
367  .url_close = sctp_close,
368  .url_get_file_handle = sctp_get_file_handle,
369  .priv_data_size = sizeof(SCTPContext),
371  .priv_data_class = &sctp_class,
372 };
D
#define D
Definition: sctp.c:161
options
static const AVOption options[]
Definition: sctp.c:163
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
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