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/*

 * SCTP protocol

 * Copyright (c) 2012 Luca Barbato

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 *

 * sctp url_protocol

 *

 * url syntax: sctp://host:port[?option=val...]

 * option: 'listen'        : listen for an incoming connection

 *         'max_streams=n' : set the maximum number of streams

 *         'reuse=1'       : enable reusing the socket [TBD]

 *

 * by setting the maximum number of streams the protocol will use the

 * first two bytes of the incoming/outgoing buffer to store the

 * stream number of the packet being read/written.

 * @see sctp_read

 * @see sctp_write

 */

#include 

#include 

#include "config.h"

#if HAVE_POLL_H

#include 

#endif

#include "libavutil/intreadwrite.h"

#include "libavutil/parseutils.h"

#include "avformat.h"

#include "internal.h"

#include "network.h"

#include "os_support.h"

#include "url.h"

/*

 * The sctp_recvmsg and sctp_sendmsg functions are part of the user

 * library that offers support for the SCTP kernel Implementation.

 * To avoid build-time clashes the functions sport an ff_-prefix here.

 * The main purpose of this code is to provide the SCTP Socket API

 * mappings for user applications to interface with SCTP in the kernel.

 *

 * This implementation is based on the Socket API Extensions for SCTP

 * defined in 

 *

 * Copyright (c) 2003 International Business Machines, Corp.

 *

 * Written or modified by:

 *  Ryan Layer 

 */

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)

{

    int recvb;

    struct iovec iov;

    char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];

    struct msghdr inmsg  = { 0 };

    struct cmsghdr *cmsg = NULL;

    iov.iov_base = msg;

    iov.iov_len  = len;

    inmsg.msg_name       = from;

    inmsg.msg_namelen    = fromlen ? *fromlen : 0;

    inmsg.msg_iov        = &iov;

    inmsg.msg_iovlen     = 1;

    inmsg.msg_control    = incmsg;

    inmsg.msg_controllen = sizeof(incmsg);

    if ((recvb = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0)) < 0)

        return recvb;

    if (fromlen)

        *fromlen   = inmsg.msg_namelen;

    if (msg_flags)

        *msg_flags = inmsg.msg_flags;

    for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL;

         cmsg = CMSG_NXTHDR(&inmsg, cmsg)) {

        if ((IPPROTO_SCTP == cmsg->cmsg_level) &&

            (SCTP_SNDRCV  == cmsg->cmsg_type))

            break;

    }

    /* Copy sinfo. */

    if (cmsg)

        memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo));

    return recvb;

}

static int ff_sctp_send(int s, const void *msg, size_t len,

                        const struct sctp_sndrcvinfo *sinfo, int flags)

{

    struct msghdr outmsg;

    struct iovec iov;

    outmsg.msg_name       = NULL;

    outmsg.msg_namelen    = 0;

    outmsg.msg_iov        = &iov;

    iov.iov_base          = (void*)msg;

    iov.iov_len           = len;

    outmsg.msg_iovlen     = 1;

    outmsg.msg_controllen = 0;

    if (sinfo) {

        char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];

        struct cmsghdr *cmsg;

        outmsg.msg_control    = outcmsg;

        outmsg.msg_controllen = sizeof(outcmsg);

        outmsg.msg_flags      = 0;

        cmsg             = CMSG_FIRSTHDR(&outmsg);

        cmsg->cmsg_level = IPPROTO_SCTP;

        cmsg->cmsg_type  = SCTP_SNDRCV;

        cmsg->cmsg_len   = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));

        outmsg.msg_controllen = cmsg->cmsg_len;

        memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo));

    }

    return sendmsg(s, &outmsg, flags);

}

typedef struct SCTPContext {

    int fd;

    int max_streams;

    struct sockaddr_storage dest_addr;

    socklen_t dest_addr_len;

} SCTPContext;

static int sctp_open(URLContext *h, const char *uri, int flags)

{

    struct addrinfo *ai, *cur_ai;

    struct addrinfo hints             = { 0 };

    struct sctp_event_subscribe event = { 0 };

    struct sctp_initmsg initparams    = { 0 };

    int port;

    int fd         = -1;

    SCTPContext *s = h->priv_data;

    const char *p;

    char buf[256];

    int ret, listen_socket = 0;

    char hostname[1024], proto[1024], path[1024];

    char portstr[10];

    av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname),

                 &port, path, sizeof(path), uri);

    if (strcmp(proto, "sctp"))

        return AVERROR(EINVAL);

    if (port <= 0 || port >= 65536) {

        av_log(s, AV_LOG_ERROR, "Port missing in uri\n");

        return AVERROR(EINVAL);

    }

    s->max_streams = 0;

    p = strchr(uri, '?');

    if (p) {

        if (av_find_info_tag(buf, sizeof(buf), "listen", p))

            listen_socket = 1;

        if (av_find_info_tag(buf, sizeof(buf), "max_streams", p))

            s->max_streams = strtol(buf, NULL, 10);

    }

    hints.ai_family   = AF_UNSPEC;

    hints.ai_socktype = SOCK_STREAM;

    snprintf(portstr, sizeof(portstr), "%d", port);

    ret = getaddrinfo(hostname, portstr, &hints, &ai);

    if (ret) {

        av_log(h, AV_LOG_ERROR, "Failed to resolve hostname %s: %s\n",

               hostname, gai_strerror(ret));

        return AVERROR(EIO);

    }

    cur_ai = ai;

    fd = ff_socket(cur_ai->ai_family, SOCK_STREAM, IPPROTO_SCTP);

    if (fd < 0)

        goto fail;

    s->dest_addr_len = sizeof(s->dest_addr);

    if (listen_socket) {

        int fd1;

        ret = bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);

        listen(fd, 100);

        fd1 = accept(fd, NULL, NULL);

        closesocket(fd);

        fd  = fd1;

    } else

        ret = connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen);

    ff_socket_nonblock(fd, 1);

    event.sctp_data_io_event = 1;

    /* TODO: Subscribe to more event types and handle them */

    if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event,

                   sizeof(event)) != 0) {

        av_log(h, AV_LOG_ERROR,

               "SCTP ERROR: Unable to subscribe to events\n");

        goto fail;

    }

    if (s->max_streams) {

        initparams.sinit_max_instreams = s->max_streams;

        initparams.sinit_num_ostreams  = s->max_streams;

        if (setsockopt(fd, IPPROTO_SCTP, SCTP_INITMSG, &initparams,

                       sizeof(initparams)) < 0)

            av_log(h, AV_LOG_ERROR,

                   "SCTP ERROR: Unable to initialize socket max streams %d\n",

                   s->max_streams);

    }

    h->priv_data   = s;

    h->is_streamed = 1;

    s->fd          = fd;

    freeaddrinfo(ai);

    return 0;

fail:

    ret = AVERROR(EIO);

    freeaddrinfo(ai);

    return ret;

}

static int sctp_wait_fd(int fd, int write)

{

    int ev          = write ? POLLOUT : POLLIN;

    struct pollfd p = { .fd = fd, .events = ev, .revents = 0 };

    int ret;

    ret = poll(&p, 1, 100);

    return ret < 0 ? ff_neterrno() : p.revents & ev ? 0 : AVERROR(EAGAIN);

}

static int sctp_read(URLContext *h, uint8_t *buf, int size)

{

    SCTPContext *s = h->priv_data;

    int ret;

    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {

        ret = sctp_wait_fd(s->fd, 0);

        if (ret < 0)

            return ret;

    }

    if (s->max_streams) {

        /*StreamId is introduced as a 2byte code into the stream*/

        struct sctp_sndrcvinfo info = { 0 };

        ret = ff_sctp_recvmsg(s->fd, buf + 2, size - 2, NULL, 0, &info, 0);

        AV_WB16(buf, info.sinfo_stream);

        ret = ret < 0 ? ret : ret + 2;

    } else

        ret = recv(s->fd, buf, size, 0);

    return ret < 0 ? ff_neterrno() : ret;

}

static int sctp_write(URLContext *h, const uint8_t *buf, int size)

{

    SCTPContext *s = h->priv_data;

    int ret;

    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {

        ret = sctp_wait_fd(s->fd, 1);

        if (ret < 0)

            return ret;

    }

    if (s->max_streams) {

        /*StreamId is introduced as a 2byte code into the stream*/

        struct sctp_sndrcvinfo info = { 0 };

        info.sinfo_stream           = AV_RB16(buf);

        if (info.sinfo_stream > s->max_streams) {

            av_log(h, AV_LOG_ERROR, "bad input data\n");

            return AVERROR(EINVAL);

        }

        ret = ff_sctp_send(s->fd, buf + 2, size - 2, &info, MSG_EOR);

    } else

        ret = send(s->fd, buf, size, 0);

    return ret < 0 ? ff_neterrno() : ret;

}

static int sctp_close(URLContext *h)

{

    SCTPContext *s = h->priv_data;

    closesocket(s->fd);

    return 0;

}

static int sctp_get_file_handle(URLContext *h)

{

    SCTPContext *s = h->priv_data;

    return s->fd;

}

URLProtocol ff_sctp_protocol = {

    .name                = "sctp",

    .url_open            = sctp_open,

    .url_read            = sctp_read,

    .url_write           = sctp_write,

    .url_close           = sctp_close,

    .url_get_file_handle = sctp_get_file_handle,

    .priv_data_size      = sizeof(SCTPContext),

    .flags               = URL_PROTOCOL_FLAG_NETWORK,

};