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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 "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 for the SCTP kernel Implementation.
  60.  * To avoid build-time clashes the functions sport an ff_-prefix here.
  61.  * The main purpose of this code is to provide the SCTP Socket API
  62.  * mappings for user applications to interface with SCTP in the 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          = (void*)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 = ff_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.             av_log(h, AV_LOG_ERROR, "bad input data\n");
  301.             return AVERROR(EINVAL);
  302.         }
  303.         ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);
  304.     } else
  305.         ret = send(s->fd, buf, size, 0);
  306.  
  307.     return ret < 0 ? ff_neterrno() : ret;
  308. }
  309.  
  310. static int sctp_close(URLContext *h)
  311. {
  312.     SCTPContext *s = h->priv_data;
  313.     closesocket(s->fd);
  314.     return 0;
  315. }
  316.  
  317. static int sctp_get_file_handle(URLContext *h)
  318. {
  319.     SCTPContext *s = h->priv_data;
  320.     return s->fd;
  321. }
  322.  
  323. URLProtocol ff_sctp_protocol = {
  324.     .name                = "sctp",
  325.     .url_open            = sctp_open,
  326.     .url_read            = sctp_read,
  327.     .url_write           = sctp_write,
  328.     .url_close           = sctp_close,
  329.     .url_get_file_handle = sctp_get_file_handle,
  330.     .priv_data_size      = sizeof(SCTPContext),
  331.     .flags               = URL_PROTOCOL_FLAG_NETWORK,
  332. };
  333.