/*
  * TCP protocol

  * Copyright (c) 2002 Fabrice Bellard

  *

  * 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

  */
 #include "avformat.h"

 #include "libavutil/avassert.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/opt.h"

 #include "libavutil/time.h"

 #include "internal.h"

 #include "network.h"

 #include "os_support.h"

 #include "url.h"

 #if HAVE_POLL_H
 #include <poll.h>

 #endif

 
 typedef struct TCPContext {

     const AVClass *class;

     int fd;

     int listen;

     int open_timeout;

     int rw_timeout;
     int listen_timeout;

     int recv_buffer_size;
     int send_buffer_size;

 } TCPContext;
 

 #define OFFSET(x) offsetof(TCPContext, 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_INT, { .i64 = 0 },     0,       2,       .flags = D|E },

     { "timeout",     "set timeout (in microseconds) of socket I/O operations", OFFSET(rw_timeout),     AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },

     { "listen_timeout",  "Connection awaiting timeout (in milliseconds)",      OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },

     { "send_buffer_size", "Socket send buffer size (in bytes)",                OFFSET(send_buffer_size), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
     { "recv_buffer_size", "Socket receive buffer size (in bytes)",             OFFSET(recv_buffer_size), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },

     { NULL }

 };
 

 static const AVClass tcp_class = {

     .class_name = "tcp",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 /* return non zero if error */
 static int tcp_open(URLContext *h, const char *uri, int flags)
 {

     struct addrinfo hints = { 0 }, *ai, *cur_ai;

     int port, fd = -1;

     TCPContext *s = h->priv_data;

     const char *p;
     char buf[256];

     int ret;

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

     char portstr[10];

     s->open_timeout = 5000000;

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

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

     if (strcmp(proto, "tcp"))

         return AVERROR(EINVAL);

     if (port <= 0 || port >= 65536) {
         av_log(h, 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)) {
             char *endptr = NULL;
             s->listen = strtol(buf, &endptr, 10);
             /* assume if no digits were found it is a request to enable it */
             if (buf == endptr)
                 s->listen = 1;
         }

         if (av_find_info_tag(buf, sizeof(buf), "timeout", p)) {

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

         }

         if (av_find_info_tag(buf, sizeof(buf), "listen_timeout", p)) {

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

         }

     }

     if (s->rw_timeout >= 0) {
         s->open_timeout =
         h->rw_timeout   = s->rw_timeout;
     }

     hints.ai_family = AF_UNSPEC;

     hints.ai_socktype = SOCK_STREAM;
     snprintf(portstr, sizeof(portstr), "%d", port);

     if (s->listen)

         hints.ai_flags |= AI_PASSIVE;

     if (!hostname[0])
         ret = getaddrinfo(NULL, portstr, &hints, &ai);
     else
         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:

 #if HAVE_STRUCT_SOCKADDR_IN6

     // workaround for IOS9 getaddrinfo in IPv6 only network use hardcode IPv4 address can not resolve port number.
     if (cur_ai->ai_family == AF_INET6){
         struct sockaddr_in6 * sockaddr_v6 = (struct sockaddr_in6 *)cur_ai->ai_addr;
         if (!sockaddr_v6->sin6_port){
             sockaddr_v6->sin6_port = htons(port);
         }
     }

 #endif

     fd = ff_socket(cur_ai->ai_family,
                    cur_ai->ai_socktype,
                    cur_ai->ai_protocol);

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

         goto fail;

     }

     /* Set the socket's send or receive buffer sizes, if specified.
        If unspecified or setting fails, system default is used. */
     if (s->recv_buffer_size > 0) {
         setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &s->recv_buffer_size, sizeof (s->recv_buffer_size));
     }
     if (s->send_buffer_size > 0) {
         setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &s->send_buffer_size, sizeof (s->send_buffer_size));
     }
 

     if (s->listen == 2) {
         // multi-client
         if ((ret = ff_listen(fd, cur_ai->ai_addr, cur_ai->ai_addrlen)) < 0)
             goto fail1;
     } else if (s->listen == 1) {
         // single client

         if ((ret = ff_listen_bind(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
                                   s->listen_timeout, h)) < 0)

             goto fail1;

         // Socket descriptor already closed here. Safe to overwrite to client one.
         fd = ret;

     } else {

         if ((ret = ff_listen_connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,

                                      s->open_timeout / 1000, h, !!cur_ai->ai_next)) < 0) {

             if (ret == AVERROR_EXIT)

                 goto fail1;

             else
                 goto fail;

         }

     }

     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:

     if (fd >= 0)

         closesocket(fd);

     freeaddrinfo(ai);

     return ret;

 }
 

 static int tcp_accept(URLContext *s, URLContext **c)
 {
     TCPContext *sc = s->priv_data;
     TCPContext *cc;
     int ret;
     av_assert0(sc->listen);
     if ((ret = ffurl_alloc(c, s->filename, s->flags, &s->interrupt_callback)) < 0)
         return ret;
     cc = (*c)->priv_data;
     ret = ff_accept(sc->fd, sc->listen_timeout, s);
     if (ret < 0)

         return ret;

     cc->fd = ret;
     return 0;
 }
 

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

 {
     TCPContext *s = h->priv_data;

     int ret;

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

         ret = ff_network_wait_fd_timeout(s->fd, 0, h->rw_timeout, &h->interrupt_callback);
         if (ret)

             return ret;

     }

     ret = recv(s->fd, buf, size, 0);
     return ret < 0 ? ff_neterrno() : ret;

 }
 

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

 {
     TCPContext *s = h->priv_data;

     int ret;

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

         ret = ff_network_wait_fd_timeout(s->fd, 1, h->rw_timeout, &h->interrupt_callback);
         if (ret)

             return ret;

     }

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

     return ret < 0 ? ff_neterrno() : ret;

 }
 

 static int tcp_shutdown(URLContext *h, int flags)
 {
     TCPContext *s = h->priv_data;
     int how;
 
     if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {
         how = SHUT_RDWR;
     } else if (flags & AVIO_FLAG_WRITE) {
         how = SHUT_WR;
     } else {
         how = SHUT_RD;
     }
 
     return shutdown(s->fd, how);
 }
 

 static int tcp_close(URLContext *h)
 {
     TCPContext *s = h->priv_data;

     closesocket(s->fd);

     return 0;
 }
 

 static int tcp_get_file_handle(URLContext *h)
 {
     TCPContext *s = h->priv_data;
     return s->fd;
 }
 

 static int tcp_get_window_size(URLContext *h)
 {
     TCPContext *s = h->priv_data;
     int avail;
     int avail_len = sizeof(avail);
 
 #if HAVE_WINSOCK2_H
     /* SO_RCVBUF with winsock only reports the actual TCP window size when
     auto-tuning has been disabled via setting SO_RCVBUF */
     if (s->recv_buffer_size < 0) {
         return AVERROR(ENOSYS);
     }
 #endif
 
     if (getsockopt(s->fd, SOL_SOCKET, SO_RCVBUF, &avail, &avail_len)) {
         return ff_neterrno();
     }
     return avail;
 }
 

 const URLProtocol ff_tcp_protocol = {

     .name                = "tcp",
     .url_open            = tcp_open,

     .url_accept          = tcp_accept,

     .url_read            = tcp_read,
     .url_write           = tcp_write,
     .url_close           = tcp_close,

     .url_get_file_handle = tcp_get_file_handle,

     .url_get_short_seek  = tcp_get_window_size,

     .url_shutdown        = tcp_shutdown,

     .priv_data_size      = sizeof(TCPContext),

     .flags               = URL_PROTOCOL_FLAG_NETWORK,

     .priv_data_class     = &tcp_class,

 };