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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) {
251  av_log(h, AV_LOG_ERROR,
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) {
261  av_log(h, AV_LOG_ERROR,
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 };
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:4373
#define NULL
Definition: coverity.c:32
struct sockaddr_storage dest_addr
Definition: sctp.c:157
static int ff_sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from, socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo, int *msg_flags)
Definition: sctp.c:74
const char * s
Definition: avisynth_c.h:631
#define URL_PROTOCOL_FLAG_NETWORK
Definition: url.h:34
AVOption.
Definition: opt.h:245
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
int is_streamed
true if streamed (no seek possible), default = false
Definition: url.h:45
static const AVClass sctp_class
Definition: sctp.c:171
static int sctp_write(URLContext *h, const uint8_t *buf, int size)
Definition: sctp.c:323
int flags
Definition: url.h:43
#define freeaddrinfo
Definition: network.h:208
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 ff_socket(int af, int type, int proto)
Definition: network.c:166
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
int ff_listen_bind(int fd, const struct sockaddr *addr, socklen_t addrlen, int timeout, URLContext *h)
Bind to a file descriptor and poll for a connection.
Definition: network.c:226
uint8_t
int timeout
Definition: sctp.c:154
AVOptions.
miscellaneous OS support macros and functions.
const char * from
Definition: jacosubdec.c:65
int ff_listen_connect(int fd, const struct sockaddr *addr, socklen_t addrlen, int timeout, URLContext *h, int will_try_next)
Connect to a file descriptor and poll for result.
Definition: network.c:238
int av_find_info_tag(char *arg, int arg_size, const char *tag1, const char *info)
Attempt to find a specific tag in a URL.
Definition: parseutils.c:705
#define D
Definition: sctp.c:161
ptrdiff_t size
Definition: opengl_enc.c:101
#define AV_WB16(p, v)
Definition: intreadwrite.h:405
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
static int sctp_close(URLContext *h)
Definition: sctp.c:349
av_default_item_name
#define closesocket
Definition: ffserver.c:28
#define AVERROR(e)
Definition: error.h:43
#define fail()
Definition: checkasm.h:82
#define E
Definition: sctp.c:162
int ai_addrlen
Definition: network.h:132
static int sctp_get_file_handle(URLContext *h)
Definition: sctp.c:356
static int sctp_wait_fd(int fd, int write)
Definition: sctp.c:290
#define ff_neterrno()
Definition: network.h:64
int listen
Definition: sctp.c:153
#define AVERROR_EXIT
Immediate exit was requested; the called function should not be restarted.
Definition: error.h:56
static int ff_sctp_send(int s, const void *msg, size_t len, const struct sctp_sndrcvinfo *sinfo, int flags)
Definition: sctp.c:116
#define AVIO_FLAG_NONBLOCK
Use non-blocking mode.
Definition: avio.h:625
void * buf
Definition: avisynth_c.h:553
Definition: url.h:38
#define AVERROR_BUG
Internal bug, also see AVERROR_BUG2.
Definition: error.h:50
Describe the class of an AVClass context structure.
Definition: log.h:67
void * priv_data
Definition: url.h:41
#define gai_strerror
Definition: network.h:215
#define snprintf
Definition: snprintf.h:34
int listen_timeout
Definition: sctp.c:155
static const AVOption options[]
Definition: sctp.c:163
misc parsing utilities
static int sctp_open(URLContext *h, const char *uri, int flags)
Definition: sctp.c:178
const URLProtocol ff_sctp_protocol
Definition: sctp.c:362
const char * name
Definition: url.h:54
int ai_socktype
Definition: network.h:130
int fd
Definition: sctp.c:152
static int flags
Definition: cpu.c:47
static int sctp_read(URLContext *h, uint8_t *buf, int size)
Definition: sctp.c:300
#define getaddrinfo
Definition: network.h:207
Main libavformat public API header.
struct addrinfo * ai_next
Definition: network.h:135
int len
#define MSG_NOSIGNAL
Definition: network.h:123
unbuffered private I/O API
struct sockaddr * ai_addr
Definition: network.h:133
#define OFFSET(x)
Definition: sctp.c:160
int max_streams
Definition: sctp.c:156
int ai_family
Definition: network.h:129