/*
  * 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 <netinet/in.h>
 #include <netinet/sctp.h>
 
 #include "config.h"
 
 #if HAVE_POLL_H
 #include <poll.h>
 #endif
 
 #include "libavutil/intreadwrite.h"
 #include "libavutil/parseutils.h"

 #include "libavutil/opt.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 <draft-ietf-tsvwg-sctpsocket-10.txt>
  *
  * Copyright (c) 2003 International Business Machines, Corp.
  *
  * Written or modified by:
  *  Ryan Layer <rmlayer@us.ibm.com>
  */
 
 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;

          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 = { 0 };

     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 | MSG_NOSIGNAL);

 }
 
 typedef struct SCTPContext {

     const AVClass *class;

     int fd;

     int listen;
     int timeout;
     int listen_timeout;

     int max_streams;
     struct sockaddr_storage dest_addr;
 } SCTPContext;
 

 #define OFFSET(x) offsetof(SCTPContext, x)
 #define D AV_OPT_FLAG_DECODING_PARAM
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {

     { "listen",          "Listen for incoming connections",  OFFSET(listen),         AV_OPT_TYPE_BOOL,{ .i64 = 0 },     0,       1,         .flags = D|E },

     { "timeout",         "Connection timeout (in milliseconds)", OFFSET(timeout),    AV_OPT_TYPE_INT, { .i64 = 10000 }, INT_MIN, INT_MAX,   .flags = D|E },
     { "listen_timeout",  "Bind timeout (in milliseconds)",   OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },    INT_MIN, INT_MAX,   .flags = D|E },
     { "max_streams",     "Max stream to allocate",           OFFSET(max_streams), AV_OPT_TYPE_INT, { .i64 = 0 },              0, INT16_MAX, .flags = D|E },
     { NULL }
 };
 
 static const AVClass sctp_class = {
     .class_name = "sctp",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 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;

     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);
     }

 
     p = strchr(uri, '?');
     if (p) {
         if (av_find_info_tag(buf, sizeof(buf), "listen", p))

             s->listen = 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;
 

 restart:

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

     if (fd < 0) {
         ret = ff_neterrno();

         goto fail;

     }

     if (s->listen) {
         if ((fd = ff_listen_bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
                                  s->listen_timeout, h)) < 0) {
             ret = fd;
             goto fail1;
         }
     } else {
         if ((ret = ff_listen_connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
                                      s->timeout, h, !!cur_ai->ai_next)) < 0) {
 
             if (ret == AVERROR_EXIT)
                 goto fail1;
             else
                 goto fail;
         }
     }

 
     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 fail1;

     }
 
     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);

             ret = ff_neterrno();
             goto fail1;
         }

     }
 
     h->priv_data   = s;
     h->is_streamed = 1;
     s->fd          = fd;
     freeaddrinfo(ai);
     return 0;
 
 fail:

     if (cur_ai->ai_next) {
         /* Retry with the next sockaddr */
         cur_ai = cur_ai->ai_next;
         if (fd >= 0)
             closesocket(fd);
         ret = 0;
         goto restart;
     }
 fail1:

     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_BUG;

         }

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

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

 
     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;
 }
 

 const 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,

     .priv_data_class     = &sctp_class,

 };