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 "avformat.h"
  52 #include "internal.h"
  53 #include "network.h"
  54 #include "os_support.h"
  55 #include "url.h"
  56
  57 /*
  58  * The sctp_recvmsg and sctp_sendmsg functions are part of the user
  59  * library that offers support
  60  * for the SCTP kernel Implementation. The main purpose of this
  61  * code is to provide the SCTP Socket API mappings for user
  62  * application to interface with the SCTP in kernel.
  63  *
  64  * This implementation is based on the Socket API Extensions for SCTP
  65  * defined in <draft-ietf-tsvwg-sctpsocket-10.txt>
  66  *
  67  * Copyright (c) 2003 International Business Machines, Corp.
  68  *
  69  * Written or modified by:
  70  *  Ryan Layer <rmlayer@us.ibm.com>
  71  */
  72
  73 static int ff_sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
  74                            socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo,
  75                            int *msg_flags)
  76 {
  77     int recvb;
  78     struct iovec iov;
  79     char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
  80     struct msghdr inmsg  = { 0 };
  81     struct cmsghdr *cmsg = NULL;
  82
  83     iov.iov_base = msg;
  84     iov.iov_len  = len;
  85
  86     inmsg.msg_name       = from;
  87     inmsg.msg_namelen    = fromlen ? *fromlen : 0;
  88     inmsg.msg_iov        = &iov;
  89     inmsg.msg_iovlen     = 1;
  90     inmsg.msg_control    = incmsg;
  91     inmsg.msg_controllen = sizeof(incmsg);
  92
  93     if ((recvb = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0)) < 0)
  94         return recvb;
  95
  96     if (fromlen)
  97         *fromlen   = inmsg.msg_namelen;
  98     if (msg_flags)
  99         *msg_flags = inmsg.msg_flags;
 100
 101     for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL;
 102          cmsg = CMSG_NXTHDR(&inmsg, cmsg)) {
 103         if ((IPPROTO_SCTP == cmsg->cmsg_level) &&
 104             (SCTP_SNDRCV  == cmsg->cmsg_type))
 105             break;
 106     }
 107
 108     /* Copy sinfo. */
 109     if (cmsg)
 110         memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo));
 111
 112     return recvb;
 113 }
 114
 115 static int ff_sctp_send(int s, const void *msg, size_t len,
 116                         const struct sctp_sndrcvinfo *sinfo, int flags)
 117 {
 118     struct msghdr outmsg;
 119     struct iovec iov;
 120
 121     outmsg.msg_name       = NULL;
 122     outmsg.msg_namelen    = 0;
 123     outmsg.msg_iov        = &iov;
 124     iov.iov_base          = msg;
 125     iov.iov_len           = len;
 126     outmsg.msg_iovlen     = 1;
 127     outmsg.msg_controllen = 0;
 128
 129     if (sinfo) {
 130         char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
 131         struct cmsghdr *cmsg;
 132
 133         outmsg.msg_control    = outcmsg;
 134         outmsg.msg_controllen = sizeof(outcmsg);
 135         outmsg.msg_flags      = 0;
 136
 137         cmsg             = CMSG_FIRSTHDR(&outmsg);
 138         cmsg->cmsg_level = IPPROTO_SCTP;
 139         cmsg->cmsg_type  = SCTP_SNDRCV;
 140         cmsg->cmsg_len   = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
 141
 142         outmsg.msg_controllen = cmsg->cmsg_len;
 143         memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo));
 144     }
 145
 146     return sendmsg(s, &outmsg, flags);
 147 }
 148
 149 typedef struct SCTPContext {
 150     int fd;
 151     int max_streams;
 152     struct sockaddr_storage dest_addr;
 153     socklen_t dest_addr_len;
 154 } SCTPContext;
 155
 156 static int sctp_open(URLContext *h, const char *uri, int flags)
 157 {
 158     struct addrinfo *ai, *cur_ai;
 159     struct addrinfo hints             = { 0 };
 160     struct sctp_event_subscribe event = { 0 };
 161     struct sctp_initmsg initparams    = { 0 };
 162     int port;
 163     int fd         = -1;
 164     SCTPContext *s = h->priv_data;
 165     const char *p;
 166     char buf[256];
 167     int ret, listen_socket = 0;
 168     char hostname[1024], proto[1024], path[1024];
 169     char portstr[10];
 170
 171     av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),
 172                  &port, path, sizeof(path), uri);
 173     if (strcmp(proto, "sctp"))
 174         return AVERROR(EINVAL);
 175     if (port <= 0 || port >= 65536) {
 176         av_log(s, AV_LOG_ERROR, "Port missing in uri\n");
 177         return AVERROR(EINVAL);
 178     }
 179
 180     s->max_streams = 0;
 181     p = strchr(uri, '?');
 182     if (p) {
 183         if (av_find_info_tag(buf, sizeof(buf), "listen", p))
 184             listen_socket = 1;
 185         if (av_find_info_tag(buf, sizeof(buf), "max_streams", p))
 186             s->max_streams = strtol(buf, NULL, 10);
 187     }
 188
 189     hints.ai_family   = AF_UNSPEC;
 190     hints.ai_socktype = SOCK_STREAM;
 191     snprintf(portstr, sizeof(portstr), "%d", port);
 192     ret = getaddrinfo(hostname, portstr, &hints, &ai);
 193     if (ret) {
 194         av_log(h, AV_LOG_ERROR, "Failed to resolve hostname %s: %s\n",
 195                hostname, gai_strerror(ret));
 196         return AVERROR(EIO);
 197     }
 198
 199     cur_ai = ai;
 200
 201     fd = socket(cur_ai->ai_family, SOCK_STREAM, IPPROTO_SCTP);
 202     if (fd < 0)
 203         goto fail;
 204
 205     s->dest_addr_len = sizeof(s->dest_addr);
 206
 207     if (listen_socket) {
 208         int fd1;
 209         ret = bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);
 210         listen(fd, 100);
 211         fd1 = accept(fd, NULL, NULL);
 212         closesocket(fd);
 213         fd  = fd1;
 214     } else
 215         ret = connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);
 216
 217     ff_socket_nonblock(fd, 1);
 218
 219     event.sctp_data_io_event = 1;
 220     /* TODO: Subscribe to more event types and handle them */
 221
 222     if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event,
 223                    sizeof(event)) != 0) {
 224         av_log(h, AV_LOG_ERROR,
 225                "SCTP ERROR: Unable to subscribe to events\n");
 226         goto fail;
 227     }
 228
 229     if (s->max_streams) {
 230         initparams.sinit_max_instreams = s->max_streams;
 231         initparams.sinit_num_ostreams  = s->max_streams;
 232         if (setsockopt(fd, IPPROTO_SCTP, SCTP_INITMSG, &initparams,
 233                        sizeof(initparams)) < 0)
 234             av_log(h, AV_LOG_ERROR,
 235                    "SCTP ERROR: Unable to initialize socket max streams %d\n",
 236                    s->max_streams);
 237     }
 238
 239     h->priv_data   = s;
 240     h->is_streamed = 1;
 241     s->fd          = fd;
 242     freeaddrinfo(ai);
 243     return 0;
 244
 245 fail:
 246     ret = AVERROR(EIO);
 247     freeaddrinfo(ai);
 248     return ret;
 249 }
 250
 251 static int sctp_wait_fd(int fd, int write)
 252 {
 253     int ev          = write ? POLLOUT : POLLIN;
 254     struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };
 255     int ret;
 256
 257     ret = poll(&p, 1, 100);
 258     return ret < 0 ? ff_neterrno() : p.revents & ev ? 0 : AVERROR(EAGAIN);
 259 }
 260
 261 static int sctp_read(URLContext *h, uint8_t *buf, int size)
 262 {
 263     SCTPContext *s = h->priv_data;
 264     int ret;
 265
 266     if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
 267         ret = sctp_wait_fd(s->fd, 0);
 268         if (ret < 0)
 269             return ret;
 270     }
 271
 272     if (s->max_streams) {
 273         /*StreamId is introduced as a 2byte code into the stream*/
 274         struct sctp_sndrcvinfo info = { 0 };
 275         ret = ff_sctp_recvmsg(s->fd, buf + 2, size - 2, NULL, 0, &info, 0);
 276         AV_WB16(buf, info.sinfo_stream);
 277         ret = ret < 0 ? ret : ret + 2;
 278     } else
 279         ret = recv(s->fd, buf, size, 0);
 280
 281     return ret < 0 ? ff_neterrno() : ret;
 282 }
 283
 284 static int sctp_write(URLContext *h, const uint8_t *buf, int size)
 285 {
 286     SCTPContext *s = h->priv_data;
 287     int ret;
 288
 289     if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
 290         ret = sctp_wait_fd(s->fd, 1);
 291         if (ret < 0)
 292             return ret;
 293     }
 294
 295     if (s->max_streams) {
 296         /*StreamId is introduced as a 2byte code into the stream*/
 297         struct sctp_sndrcvinfo info = { 0 };
 298         info.sinfo_stream           = AV_RB16(buf);
 299         if (info.sinfo_stream > s->max_streams)
 300             abort();
 301         ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);
 302     } else
 303         ret = send(s->fd, buf, size, 0);
 304
 305     return ret < 0 ? ff_neterrno() : ret;
 306 }
 307
 308 static int sctp_close(URLContext *h)
 309 {
 310     SCTPContext *s = h->priv_data;
 311     closesocket(s->fd);
 312     return 0;
 313 }
 314
 315 static int sctp_get_file_handle(URLContext *h)
 316 {
 317     SCTPContext *s = h->priv_data;
 318     return s->fd;
 319 }
 320
 321 URLProtocol ff_sctp_protocol = {
 322     .name                = "sctp",
 323     .url_open            = sctp_open,
 324     .url_read            = sctp_read,
 325     .url_write           = sctp_write,
 326     .url_close           = sctp_close,
 327     .url_get_file_handle = sctp_get_file_handle,
 328     .priv_data_size      = sizeof(SCTPContext),
 329     .flags               = URL_PROTOCOL_FLAG_NETWORK,
 330 };