libavformat/sctp.c

   1 /*
   2  * SCTP protocol
   3  * Copyright (c) 2012 Luca Barbato
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 != NULL;
 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;
 120     struct iovec iov;
 121
 122     outmsg.msg_name       = NULL;
 123     outmsg.msg_namelen    = 0;
 124     outmsg.msg_iov        = &iov;
 125     iov.iov_base          = 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;
 155     int listen_timeout;
 156     int max_streams;
 157     struct sockaddr_storage dest_addr;
 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_INT, { .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             return AVERROR_BUG;
 340         ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);
 341     } else
 342         ret = send(s->fd, buf, size, MSG_NOSIGNAL);
 343
 344     return ret < 0 ? ff_neterrno() : ret;
 345 }
 346
 347 static int sctp_close(URLContext *h)
 348 {
 349     SCTPContext *s = h->priv_data;
 350     closesocket(s->fd);
 351     return 0;
 352 }
 353
 354 static int sctp_get_file_handle(URLContext *h)
 355 {
 356     SCTPContext *s = h->priv_data;
 357     return s->fd;
 358 }
 359
 360 URLProtocol ff_sctp_protocol = {
 361     .name                = "sctp",
 362     .url_open            = sctp_open,
 363     .url_read            = sctp_read,
 364     .url_write           = sctp_write,
 365     .url_close           = sctp_close,
 366     .url_get_file_handle = sctp_get_file_handle,
 367     .priv_data_size      = sizeof(SCTPContext),
 368     .flags               = URL_PROTOCOL_FLAG_NETWORK,
 369     .priv_data_class     = &sctp_class,
 370 };