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udp.c：源码内容
							/*****************************************************************************
 * udp.c
 *****************************************************************************
 * Copyright (C) 2001, 2002 VideoLAN
 * $Id: udp.c 8769 2004-09-22 15:25:11Z gbazin $
 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *          Eric Petit <titer@videolan.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/
/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <vlc/vlc.h>
#include <vlc/sout.h>
#ifdef HAVE_UNISTD_H
#   include <unistd.h>
#endif
#ifdef WIN32
#   include <winsock2.h>
#   include <ws2tcpip.h>
#   ifndef IN_MULTICAST
#       define IN_MULTICAST(a) IN_CLASSD(a)
#   endif
#else
#   include <sys/socket.h>
#endif
#include "network.h"
/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );
#define SOUT_CFG_PREFIX "sout-udp-"
#define CACHING_TEXT N_("Caching value (ms)")
#define CACHING_LONGTEXT N_( 
    "Allows you to modify the default caching value for UDP streams. This " 
    "value should be set in millisecond units." )
#define TTL_TEXT N_("Time To Live")
#define TTL_LONGTEXT N_("Allows you to define the time to live of the " 
                        "outgoing stream.")
#define GROUP_TEXT N_("Group packets")
#define GROUP_LONGTEXT N_("Packets can be sent one by one at the right time " 
                          "or by groups. This allows you to give the number " 
                          "of packets that will be sent at a time. It " 
                          "helps reducing the scheduling load on " 
                          "heavily-loaded systems." )
#define LATE_TEXT N_("Late delay (ms)" )
#define LATE_LONGTEXT N_("Late packets are dropped. This allows you to give " 
                       "the time (in milliseconds) a packet is allowed to be" 
                       " late.")
#define RAW_TEXT N_("Raw write")
#define RAW_LONGTEXT N_("If you enable this option, packets will be sent " 
                       "directly, without trying to fill the MTU (ie, " 
                       "without trying to make the biggest possible packets " 
                       "in order to improve streaming)." )
vlc_module_begin();
    set_description( _("UDP stream output") );
    add_integer( SOUT_CFG_PREFIX "caching", DEFAULT_PTS_DELAY / 1000, NULL, CACHING_TEXT, CACHING_LONGTEXT, VLC_TRUE );
    add_integer( SOUT_CFG_PREFIX "ttl", 0, NULL,TTL_TEXT, TTL_LONGTEXT,
                                 VLC_TRUE );
    add_integer( SOUT_CFG_PREFIX "group", 1, NULL, GROUP_TEXT, GROUP_LONGTEXT,
                                 VLC_TRUE );
    add_integer( SOUT_CFG_PREFIX "late", 0, NULL, LATE_TEXT, LATE_LONGTEXT,
                                 VLC_TRUE );
    add_bool( SOUT_CFG_PREFIX "raw",  0, NULL, RAW_TEXT, RAW_LONGTEXT,
                                 VLC_TRUE );
    set_capability( "sout access", 100 );
    add_shortcut( "udp" );
    add_shortcut( "rtp" ); // Will work only with ts muxer
    set_callbacks( Open, Close );
vlc_module_end();
/*****************************************************************************
 * Exported prototypes
 *****************************************************************************/
static const char *ppsz_sout_options[] = {
    "caching",
    "ttl",
    "group",
    "late",
    "raw",
    NULL
};
static int  Write   ( sout_access_out_t *, block_t * );
static int  WriteRaw( sout_access_out_t *, block_t * );
static int  Seek    ( sout_access_out_t *, off_t  );
static void ThreadWrite( vlc_object_t * );
static block_t *NewUDPPacket( sout_access_out_t *, mtime_t );
typedef struct sout_access_thread_t
{
    VLC_COMMON_MEMBERS
    sout_instance_t *p_sout;
    block_fifo_t *p_fifo;
    int         i_handle;
    int64_t     i_caching;
    int64_t     i_late;
    int         i_group;
} sout_access_thread_t;
struct sout_access_out_sys_t
{
    int                 b_rtpts;  // 1 if add rtp/ts header
    uint16_t            i_sequence_number;
    uint32_t            i_ssrc;
    int                 i_mtu;
    block_t             *p_buffer;
    sout_access_thread_t *p_thread;
    vlc_bool_t          b_mtu_warning;
};
#define DEFAULT_PORT 1234
/*****************************************************************************
 * Open: open the file
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    sout_access_out_t       *p_access = (sout_access_out_t*)p_this;
    sout_access_out_sys_t   *p_sys;
    char                *psz_parser;
    char                *psz_dst_addr;
    int                 i_dst_port;
    module_t            *p_network;
    network_socket_t    socket_desc;
    vlc_value_t         val;
    sout_CfgParse( p_access, SOUT_CFG_PREFIX,
                   ppsz_sout_options, p_access->p_cfg );
    if( !( p_sys = malloc( sizeof( sout_access_out_sys_t ) ) ) )
    {
        msg_Err( p_access, "not enough memory" );
        return VLC_EGENERIC;
    }
    memset( p_sys, 0, sizeof(sout_access_out_sys_t) );
    p_access->p_sys = p_sys;
    if( p_access->psz_access != NULL &&
        !strcmp( p_access->psz_access, "rtp" ) )
    {
        msg_Warn( p_access, "be careful that rtp output only works with ts "
                  "payload (not an error)" );
        p_sys->b_rtpts = 1;
    }
    else
    {
        p_sys->b_rtpts = 0;
    }
    psz_parser = strdup( p_access->psz_name );
    psz_dst_addr = psz_parser;
    i_dst_port = 0;
    if ( *psz_parser == '[' )
    {
        while( *psz_parser && *psz_parser != ']' )
        {
            psz_parser++;
        }
    }
    while( *psz_parser && *psz_parser != ':' )
    {
        psz_parser++;
    }
    if( *psz_parser == ':' )
    {
        *psz_parser = '';
        psz_parser++;
        i_dst_port = atoi( psz_parser );
    }
    if( i_dst_port <= 0 )
    {
        i_dst_port = DEFAULT_PORT;
    }
    p_sys->p_thread =
        vlc_object_create( p_access, sizeof( sout_access_thread_t ) );
    if( !p_sys->p_thread )
    {
        msg_Err( p_access, "out of memory" );
        return VLC_EGENERIC;
    }
    p_sys->p_thread->p_sout = p_access->p_sout;
    p_sys->p_thread->b_die  = 0;
    p_sys->p_thread->b_error= 0;
    p_sys->p_thread->p_fifo = block_FifoNew( p_access );
    socket_desc.i_type = NETWORK_UDP;
    socket_desc.psz_server_addr = psz_dst_addr;
    socket_desc.i_server_port   = i_dst_port;
    socket_desc.psz_bind_addr   = "";
    socket_desc.i_bind_port     = 0;
    var_Get( p_access, SOUT_CFG_PREFIX "ttl", &val );
    socket_desc.i_ttl = val.i_int;
    p_sys->p_thread->p_private = (void*)&socket_desc;
    if( !( p_network = module_Need( p_sys->p_thread, "network", NULL, 0 ) ) )
    {
        msg_Err( p_access, "failed to open a connection (udp)" );
        return VLC_EGENERIC;
    }
    module_Unneed( p_sys->p_thread, p_network );
    p_sys->p_thread->i_handle = socket_desc.i_handle;
    var_Get( p_access, SOUT_CFG_PREFIX "caching", &val );
    p_sys->p_thread->i_caching = (int64_t)val.i_int * 1000;
    var_Get( p_access, SOUT_CFG_PREFIX "group", &val );
    p_sys->p_thread->i_group = val.i_int;
    var_Get( p_access, SOUT_CFG_PREFIX "late", &val );
    p_sys->p_thread->i_late = (int64_t)val.i_int * 1000;
    p_sys->i_mtu = socket_desc.i_mtu;
#ifdef WIN32
    if( vlc_thread_create( p_sys->p_thread, "sout write thread", ThreadWrite,
                           VLC_THREAD_PRIORITY_HIGHEST, VLC_FALSE ) )
#else
    if( vlc_thread_create( p_sys->p_thread, "sout write thread", ThreadWrite,
                           VLC_THREAD_PRIORITY_OUTPUT, VLC_FALSE ) )
#endif
    {
        msg_Err( p_access->p_sout, "cannot spawn sout access thread" );
        vlc_object_destroy( p_sys->p_thread );
        return VLC_EGENERIC;
    }
    srand( (uint32_t)mdate());
    p_sys->p_buffer          = NULL;
    p_sys->i_sequence_number = rand()&0xffff;
    p_sys->i_ssrc            = rand()&0xffffffff;
    var_Get( p_access, SOUT_CFG_PREFIX "raw", &val );
    if( val.b_bool )  p_access->pf_write = WriteRaw;
    else p_access->pf_write = Write;
    p_access->pf_seek = Seek;
    msg_Dbg( p_access, "udp access output opened(%s:%d)",
             psz_dst_addr, i_dst_port );
    free( psz_dst_addr );
    /* update p_sout->i_out_pace_nocontrol */
    p_access->p_sout->i_out_pace_nocontrol++;
    return VLC_SUCCESS;
}
/*****************************************************************************
 * Close: close the target
 *****************************************************************************/
static void Close( vlc_object_t * p_this )
{
    sout_access_out_t     *p_access = (sout_access_out_t*)p_this;
    sout_access_out_sys_t *p_sys = p_access->p_sys;
    int i;
    p_sys->p_thread->b_die = 1;
    for( i = 0; i < 10; i++ )
    {
        block_t *p_dummy = block_New( p_access, p_sys->i_mtu );
        p_dummy->i_dts = 0;
        p_dummy->i_pts = 0;
        p_dummy->i_length = 0;
        block_FifoPut( p_sys->p_thread->p_fifo, p_dummy );
    }
    vlc_thread_join( p_sys->p_thread );
    block_FifoRelease( p_sys->p_thread->p_fifo );
    if( p_sys->p_buffer ) block_Release( p_sys->p_buffer );
    net_Close( p_sys->p_thread->i_handle );
    /* update p_sout->i_out_pace_nocontrol */
    p_access->p_sout->i_out_pace_nocontrol--;
    msg_Dbg( p_access, "udp access output closed" );
    free( p_sys );
}
/*****************************************************************************
 * Write: standard write on a file descriptor.
 *****************************************************************************/
static int Write( sout_access_out_t *p_access, block_t *p_buffer )
{
    sout_access_out_sys_t *p_sys = p_access->p_sys;
    while( p_buffer )
    {
        block_t *p_next;
        int i_packets = 0;
        if( !p_sys->b_mtu_warning && p_buffer->i_buffer > p_sys->i_mtu )
        {
            msg_Warn( p_access, "packet size > MTU, you should probably "
                      "increase the MTU" );
            p_sys->b_mtu_warning = VLC_TRUE;
        }
        /* Check if there is enough space in the buffer */
        if( p_sys->p_buffer &&
            p_sys->p_buffer->i_buffer + p_buffer->i_buffer > p_sys->i_mtu )
        {
            block_FifoPut( p_sys->p_thread->p_fifo, p_sys->p_buffer );
            p_sys->p_buffer = NULL;
        }
        while( p_buffer->i_buffer )
        {
            int i_write = __MIN( p_buffer->i_buffer, p_sys->i_mtu );
            i_packets++;
            if( !p_sys->p_buffer )
            {
                p_sys->p_buffer = NewUDPPacket( p_access, p_buffer->i_dts );
                if( !p_sys->p_buffer ) break;
            }
            memcpy( p_sys->p_buffer->p_buffer + p_sys->p_buffer->i_buffer,
                    p_buffer->p_buffer, i_write );
            p_sys->p_buffer->i_buffer += i_write;
            p_buffer->p_buffer += i_write;
            p_buffer->i_buffer -= i_write;
            if( p_sys->p_buffer->i_buffer == p_sys->i_mtu || i_packets > 1 )
            {
                /* Flush */
                block_FifoPut( p_sys->p_thread->p_fifo, p_sys->p_buffer );
                p_sys->p_buffer = NULL;
            }
        }
        p_next = p_buffer->p_next;
        block_Release( p_buffer );
        p_buffer = p_next;
    }
    return( p_sys->p_thread->b_error ? -1 : 0 );
}
/*****************************************************************************
 * WriteRaw: write p_buffer without trying to fill mtu
 *****************************************************************************/
static int WriteRaw( sout_access_out_t *p_access, block_t *p_buffer )
{
    sout_access_out_sys_t   *p_sys = p_access->p_sys;
    block_FifoPut( p_sys->p_thread->p_fifo, p_buffer );
    return( p_sys->p_thread->b_error ? -1 : 0 );
}
/*****************************************************************************
 * Seek: seek to a specific location in a file
 *****************************************************************************/
static int Seek( sout_access_out_t *p_access, off_t i_pos )
{
    msg_Err( p_access, "UDP sout access cannot seek" );
    return -1;
}
/*****************************************************************************
 * NewUDPPacket: allocate a new UDP packet of size p_sys->i_mtu
 *****************************************************************************/
static block_t *NewUDPPacket( sout_access_out_t *p_access, mtime_t i_dts)
{
    sout_access_out_sys_t *p_sys = p_access->p_sys;
    block_t *p_buffer;
    p_buffer = block_New( p_access->p_sout, p_sys->i_mtu );
    p_buffer->i_dts = i_dts;
    p_buffer->i_buffer = 0;
    if( p_sys->b_rtpts )
    {
        mtime_t i_timestamp = p_buffer->i_dts * 9 / 100;
        /* add rtp/ts header */
        p_buffer->p_buffer[0] = 0x80;
        p_buffer->p_buffer[1] = 0x21; // mpeg2-ts
        p_buffer->p_buffer[2] = ( p_sys->i_sequence_number >> 8 )&0xff;
        p_buffer->p_buffer[3] = p_sys->i_sequence_number&0xff;
        p_sys->i_sequence_number++;
        p_buffer->p_buffer[4] = ( i_timestamp >> 24 )&0xff;
        p_buffer->p_buffer[5] = ( i_timestamp >> 16 )&0xff;
        p_buffer->p_buffer[6] = ( i_timestamp >>  8 )&0xff;
        p_buffer->p_buffer[7] = i_timestamp&0xff;
        p_buffer->p_buffer[ 8] = ( p_sys->i_ssrc >> 24 )&0xff;
        p_buffer->p_buffer[ 9] = ( p_sys->i_ssrc >> 16 )&0xff;
        p_buffer->p_buffer[10] = ( p_sys->i_ssrc >>  8 )&0xff;
        p_buffer->p_buffer[11] = p_sys->i_ssrc&0xff;
        p_buffer->i_buffer = 12;
    }
    return p_buffer;
}
/*****************************************************************************
 * ThreadWrite: Write a packet on the network at the good time.
 *****************************************************************************/
static void ThreadWrite( vlc_object_t *p_this )
{
    sout_access_thread_t *p_thread = (sout_access_thread_t*)p_this;
    mtime_t              i_date_last = -1;
    mtime_t              i_to_send = p_thread->i_group;
    int                  i_dropped_packets = 0;
    while( !p_thread->b_die )
    {
        block_t *p_pk;
        mtime_t       i_date, i_sent;
        p_pk = block_FifoGet( p_thread->p_fifo );
        i_date = p_thread->i_caching + p_pk->i_dts;
        if( i_date_last > 0 )
        {
            if( i_date - i_date_last > 2000000 )
            {
                if( !i_dropped_packets )
                    msg_Dbg( p_thread, "mmh, hole ("I64Fd" > 2s) -> drop",
                             i_date - i_date_last );
                block_Release( p_pk  );
                i_date_last = i_date;
                i_dropped_packets++;
                continue;
            }
            else if( i_date - i_date_last < 0 )
            {
                if( !i_dropped_packets )
                    msg_Dbg( p_thread, "mmh, packets in the past ("I64Fd")"
                             " -> drop", i_date - i_date_last );
                block_Release( p_pk  );
                i_date_last = i_date;
                i_dropped_packets++;
                continue;
            }
        }
        i_sent = mdate();
        if( p_thread->i_late > 0 && i_sent > i_date + p_thread->i_late )
        {
            if( !i_dropped_packets )
            {
                msg_Dbg( p_thread, "late packet to send (" I64Fd ") -> drop",
                         i_sent - i_date );
            }
            block_Release( p_pk  );
            i_date_last = i_date;
            i_dropped_packets++;
            continue;
        }
        i_to_send--;
        if ( !i_to_send )
        {
            mwait( i_date );
            i_to_send = p_thread->i_group;
        }
        send( p_thread->i_handle, p_pk->p_buffer, p_pk->i_buffer, 0 );
        if( i_dropped_packets )
        {
            msg_Dbg( p_thread, "dropped %i packets", i_dropped_packets );
            i_dropped_packets = 0;
        }
#if 0
        i_sent = mdate();
        if ( i_sent > i_date + 20000 )
        {
            msg_Dbg( p_thread, "packet has been sent too late (" I64Fd ")",
                     i_sent - i_date );
        }
#endif
        block_Release( p_pk  );
        i_date_last = i_date;
    }
}

						