vlc/modules/access/udp.c

/*****************************************************************************
 * udp.c: raw UDP & RTP input module
 *****************************************************************************
 * Copyright (C) 2001-2005 the VideoLAN team
 * $Id$
 *
 * Authors: Christophe Massiot <massiot@via.ecp.fr>
 *          Tristan Leteurtre <tooney@via.ecp.fr>
 *          Laurent Aimar <fenrir@via.ecp.fr>
 *          Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
 *
 * Reviewed: 23 October 2003, Jean-Paul Saman <jpsaman _at_ videolan _dot_ 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>

#include <vlc/vlc.h>
#include <vlc_access.h>
#include <vlc_network.h>

#if defined (HAVE_NETINET_UDPLITE_H)
# include <netinet/udplite.h>
#elif defined (__linux__)
# define UDPLITE_SEND_CSCOV     10
# define UDPLITE_RECV_CSCOV     11
#endif

#ifndef IPPROTO_UDPLITE
# define IPPROTO_UDPLITE 136 /* from IANA */
#endif
#ifndef SOL_UDPLITE
# define SOL_UDPLITE IPPROTO_UDPLITE
#endif


/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define CACHING_TEXT N_("Caching value in ms")
#define CACHING_LONGTEXT N_( \
    "Caching value for UDP streams. This " \
    "value should be set in milliseconds." )

#define AUTO_MTU_TEXT N_("Autodetection of MTU")
#define AUTO_MTU_LONGTEXT N_( \
    "Automatically detect the line's MTU. This will increase the size if" \
    " truncated packets are found" )

#define RTP_LATE_TEXT N_("RTP reordering timeout in ms")
#define RTP_LATE_LONGTEXT N_( \
    "VLC reorders RTP packets. The input will wait for late packets at most "\
    "the time specified here (in milliseconds)." )

static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

vlc_module_begin();
    set_shortname( _("UDP/RTP" ) );
    set_description( _("UDP/RTP input") );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_ACCESS );

    add_integer( "udp-caching", DEFAULT_PTS_DELAY / 1000, NULL, CACHING_TEXT,
                 CACHING_LONGTEXT, VLC_TRUE );
    add_integer( "rtp-late", 100, NULL, RTP_LATE_TEXT, RTP_LATE_LONGTEXT, VLC_TRUE );

    add_bool( "udp-auto-mtu", 1, NULL,
              AUTO_MTU_TEXT, AUTO_MTU_LONGTEXT, VLC_TRUE );

    set_capability( "access2", 0 );
    add_shortcut( "udp" );
    add_shortcut( "udpstream" );
    add_shortcut( "udp4" );
    add_shortcut( "udp6" );
    add_shortcut( "rtp" );
    add_shortcut( "rtp4" );
    add_shortcut( "rtp6" );
    add_shortcut( "udplite" );
    add_shortcut( "rtplite" );

    set_callbacks( Open, Close );
vlc_module_end();

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
#define RTP_HEADER_LEN 12

static block_t *BlockUDP( access_t * );
static block_t *BlockRTP( access_t * );
static block_t *BlockChoose( access_t * );
static int Control( access_t *, int, va_list );

struct access_sys_t
{
    int fd;

    int i_mtu;
    vlc_bool_t b_auto_mtu;

    /* reorder rtp packets when out-of-sequence */
    mtime_t i_rtp_late;
    uint16_t i_last_seqno;
    block_t *p_list;
    block_t *p_end;
};

/*****************************************************************************
 * Open: open the socket
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    access_t     *p_access = (access_t*)p_this;
    access_sys_t *p_sys;

    char *psz_name = strdup( p_access->psz_path );
    char *psz_parser;
    const char *psz_server_addr, *psz_bind_addr = "";
    int  i_bind_port, i_server_port = 0;
    int fam = AF_UNSPEC, proto = IPPROTO_UDP, cscov = 8;

    if (strlen (p_access->psz_access) >= 4)
        switch (p_access->psz_access[3])
        {
            case '4':
                fam = AF_INET;
                break;

            case '6':
                fam = AF_INET6;
                break;
        }
    if (strcmp (p_access->psz_access + 3, "lite") == 0)
        proto = IPPROTO_UDPLITE;
    if (strncmp (p_access->psz_access, "rtp", 3) == 0)
        /* Checksum coverage: RTP header is AT LEAST 12 bytes
         * in addition to UDP header (8 bytes) */
        cscov += 12;

    i_bind_port = var_CreateGetInteger( p_access, "server-port" );

    /* Parse psz_name syntax :
     * [serveraddr[:serverport]][@[bindaddr]:[bindport]] */
    psz_parser = strchr( psz_name, '@' );
    if( psz_parser != NULL )
    {
        /* Found bind address and/or bind port */
        *psz_parser++ = '\0';
        psz_bind_addr = psz_parser;

        if( *psz_parser == '[' )
            /* skips bracket'd IPv6 address */
            psz_parser = strchr( psz_parser, ']' );

        if( psz_parser != NULL )
        {
            psz_parser = strchr( psz_parser, ':' );
            if( psz_parser != NULL )
            {
                *psz_parser++ = '\0';
                i_bind_port = atoi( psz_parser );
            }
        }
    }

    psz_server_addr = psz_name;
    if( *psz_server_addr == '[' )
        /* skips bracket'd IPv6 address */
        psz_parser = strchr( psz_name, ']' );

    if( psz_parser != NULL )
    {
        psz_parser = strchr( psz_parser, ':' );
        if( psz_parser != NULL )
        {
            *psz_parser++ = '\0';
            i_server_port = atoi( psz_parser );
        }
    }

    msg_Dbg( p_access, "opening server=%s:%d local=%s:%d",
             psz_server_addr, i_server_port, psz_bind_addr, i_bind_port );

    /* Set up p_access */
    access_InitFields( p_access );
    ACCESS_SET_CALLBACKS( NULL, BlockChoose, Control, NULL );
    p_access->info.b_prebuffered = VLC_FALSE;
    MALLOC_ERR( p_access->p_sys, access_sys_t ); p_sys = p_access->p_sys;

    p_sys->fd = net_Open( p_access, psz_bind_addr, i_bind_port,
                          psz_server_addr, i_server_port, fam, SOCK_DGRAM, proto );
    free (psz_name);
    if( p_sys->fd == -1 )
    {
        msg_Err( p_access, "cannot open socket" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    net_StopSend( p_sys->fd );

#ifdef UDPLITE_RECV_CSCOV
    if (proto == IPPROTO_UDPLITE)
        setsockopt (p_sys->fd, SOL_UDPLITE, UDPLITE_RECV_CSCOV, &cscov, sizeof (cscov));
#endif

    /* FIXME */
    p_sys->i_mtu = var_CreateGetInteger( p_access, "mtu" );
    if( p_sys->i_mtu <= 1 )
        p_sys->i_mtu  = 1500;   /* Avoid problem */

    p_sys->b_auto_mtu = var_CreateGetBool( p_access, "udp-auto-mtu" );;

    /* Update default_pts to a suitable value for udp access */
    var_Create( p_access, "udp-caching", VLC_VAR_INTEGER | VLC_VAR_DOINHERIT );

    /* RTP reordering for out-of-sequence packets */
    p_sys->i_rtp_late = var_CreateGetInteger( p_access, "rtp-late" ) * 1000;
    p_sys->i_last_seqno = 0;
    p_sys->p_list = NULL;
    p_sys->p_end = NULL;
    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: free unused data structures
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    access_t     *p_access = (access_t*)p_this;
    access_sys_t *p_sys = p_access->p_sys;

    block_ChainRelease( p_sys->p_list );
    net_Close( p_sys->fd );
    free( p_sys );
}

/*****************************************************************************
 * Control:
 *****************************************************************************/
static int Control( access_t *p_access, int i_query, va_list args )
{
    access_sys_t *p_sys = p_access->p_sys;
    vlc_bool_t   *pb_bool;
    int          *pi_int;
    int64_t      *pi_64;

    switch( i_query )
    {
        /* */
        case ACCESS_CAN_SEEK:
        case ACCESS_CAN_FASTSEEK:
        case ACCESS_CAN_PAUSE:
        case ACCESS_CAN_CONTROL_PACE:
            pb_bool = (vlc_bool_t*)va_arg( args, vlc_bool_t* );
            *pb_bool = VLC_FALSE;
            break;
        /* */
        case ACCESS_GET_MTU:
            pi_int = (int*)va_arg( args, int * );
            *pi_int = p_sys->i_mtu;
            break;

        case ACCESS_GET_PTS_DELAY:
            pi_64 = (int64_t*)va_arg( args, int64_t * );
            *pi_64 = var_GetInteger( p_access, "udp-caching" ) * 1000;
            break;

        /* */
        case ACCESS_SET_PAUSE_STATE:
        case ACCESS_GET_TITLE_INFO:
        case ACCESS_SET_TITLE:
        case ACCESS_SET_SEEKPOINT:
        case ACCESS_SET_PRIVATE_ID_STATE:
            return VLC_EGENERIC;

        default:
            msg_Warn( p_access, "unimplemented query in control" );
            return VLC_EGENERIC;

    }
    return VLC_SUCCESS;
}

/*****************************************************************************
 * BlockUDP:
 *****************************************************************************/
static block_t *BlockUDP( access_t *p_access )
{
    access_sys_t *p_sys = p_access->p_sys;
    block_t      *p_block;

    /* Read data */
    p_block = block_New( p_access, p_sys->i_mtu );
    p_block->i_buffer = net_Read( p_access, p_sys->fd, NULL,
                                  p_block->p_buffer, p_sys->i_mtu,
                                  VLC_FALSE );
    if( p_block->i_buffer <= 0 )
    {
        block_Release( p_block );
        return NULL;
    }

    if( (p_block->i_buffer >= p_sys->i_mtu) && p_sys->b_auto_mtu &&
        p_sys->i_mtu < 32767 )
    {
        /* Increase by 100% */
        p_sys->i_mtu *= 2;
        msg_Dbg( p_access, "increasing MTU to %d", p_sys->i_mtu );
    }

    return p_block;
}

/*
 * rtp_ChainInsert - insert a p_block in the chain and
 * look at the sequence numbers.
 */
static inline vlc_bool_t rtp_ChainInsert( access_t *p_access, block_t *p_block )
{
    access_sys_t *p_sys = (access_sys_t *) p_access->p_sys;
    block_t *p_prev = NULL;
    block_t *p = p_sys->p_end;
    uint16_t i_new = (uint16_t) p_block->i_dts;
    uint16_t i_tmp = 0;

    if( !p_sys->p_list )
    {
        p_sys->p_list = p_block;
        p_sys->p_end = p_block;
        return VLC_TRUE;
    }
    /* walk through the queue from top down since the new packet is in 
    most cases just appended to the end */

    for( ;; )
    {
        i_tmp = i_new - (uint16_t) p->i_dts;

        if( !i_tmp )   /* trash duplicate */
            break; 

        if ( i_tmp < 32768 )
        {   /* insert after this block ( i_new > p->i_dts ) */
            p_block->p_next = p->p_next;
            p->p_next = p_block;
            p_block->p_prev = p;
            if (p_prev)
            {
                p_prev->p_prev = p_block;
                msg_Dbg(p_access, "RTP reordering: insert after %d, new %d", 
                    (uint16_t) p->i_dts, i_new );
            }
            else 
            {
                p_sys->p_end = p_block;
            }
            return VLC_TRUE;
        }
        if( p == p_sys->p_list )
        {   /* we've reached bottom of chain */
            i_tmp = p_sys->i_last_seqno - i_new;
            if( !p_access->info.b_prebuffered || (i_tmp > 32767) )
            {
                msg_Dbg(p_access, "RTP reordering: prepend %d before %d", 
                        i_new, (uint16_t) p->i_dts );
                p_block->p_next = p;
                p->p_prev = p_block;
                p_sys->p_list = p_block;
                return VLC_TRUE;
            }

            if( !i_tmp )   /* trash duplicate */
                break;    

            /* reordering failed - append the packet to the end of queue */
            msg_Dbg(p_access, "RTP: sequence changed (or buffer too small) "
                "new: %d, buffer %d...%d", i_new, (uint16_t) p->i_dts, 
                (uint16_t) p_sys->p_end->i_dts);
            p_sys->p_end->p_next = p_block;
            p_block->p_prev = p_sys->p_end;
            p_sys->p_end = p_block;
            return VLC_TRUE;
        }
        p_prev = p;
        p = p->p_prev;
    }
    block_Release( p_block );
    return VLC_FALSE;
}

/*****************************************************************************
 * BlockParseRTP/BlockRTP:
 *****************************************************************************/
static block_t *BlockParseRTP( access_t *p_access, block_t *p_block )
{
    int      i_rtp_version;
    int      i_CSRC_count;
    int      i_payload_type;
    int      i_skip = 0;
    int      i_extension_flag = 0;
    int      i_extension_length = 0;
    uint16_t i_sequence_number = 0;

    if( p_block == NULL )
        return NULL;

    if( p_block->i_buffer < RTP_HEADER_LEN )
        goto trash;

    /* Parse the header and make some verifications.
     * See RFC 3550. */
    i_rtp_version     = ( p_block->p_buffer[0] & 0xC0 ) >> 6;
    i_CSRC_count      = p_block->p_buffer[0] & 0x0F;
    i_extension_flag  = p_block->p_buffer[0] & 0x10;
    i_payload_type    = p_block->p_buffer[1] & 0x7F;
    i_sequence_number = (p_block->p_buffer[2] << 8 ) + p_block->p_buffer[3];

    if( i_rtp_version != 2 )
        msg_Dbg( p_access, "RTP version is %u, should be 2", i_rtp_version );

    if( i_payload_type == 14 || i_payload_type == 32)
        i_skip = 4;
    else if( i_payload_type !=  33 )
        msg_Dbg( p_access, "unsupported RTP payload type (%u)", i_payload_type );
    if( i_extension_flag )
        i_extension_length = 4 +
            4 * ( (p_block->p_buffer[14] << 8) + p_block->p_buffer[15] );

    /* Skip header + CSRC extension field n*(32 bits) + extension */
    i_skip += RTP_HEADER_LEN + 4*i_CSRC_count + i_extension_length;

    if( i_skip >= p_block->i_buffer )
        goto trash;

    /* Return the packet without the RTP header, remember seqno in i_dts */
    p_block->i_buffer -= i_skip;
    p_block->p_buffer += i_skip;
    p_block->i_pts = mdate();
    p_block->i_dts = (mtime_t) i_sequence_number;

#if 0
    /* Emulate packet loss */
    if ( (i_sequence_number % 4000) == 0)
    {
        msg_Warn( p_access, "Emulating packet drop" );
        block_Release( p_block );
        return NULL;
    }
#endif

    return p_block;

trash:
    msg_Warn( p_access, "received a too short packet for RTP" );
    block_Release( p_block );
    return NULL;
}

static block_t *BlockPrebufferRTP( access_t *p_access, block_t *p_block )
{
    access_sys_t *p_sys = p_access->p_sys;
    mtime_t   i_first = mdate();
    int       i_count = 0;
    block_t   *p = p_block;

    for( ;; )
    {
        mtime_t i_date = mdate();

        if( p && rtp_ChainInsert( p_access, p ))
            i_count++;

        /* Require at least 2 packets in the buffer */
        if( i_count > 2 && (i_date - i_first) > p_sys->i_rtp_late )
            break;

        p = BlockParseRTP( p_access, BlockUDP( p_access ));
        if( !p && (i_date - i_first) > p_sys->i_rtp_late ) 
        {
            msg_Err( p_access, "error in RTP prebuffering!" );
            break;
        }
    }

    msg_Dbg( p_access, "RTP: prebuffered %d packets", i_count - 1 );
    p_access->info.b_prebuffered = VLC_TRUE;
    p = p_sys->p_list;
    p_sys->p_list = p_sys->p_list->p_next;
    p_sys->i_last_seqno = (uint16_t) p->i_dts;
    p->p_next = NULL;
    return p;
}

static block_t *BlockRTP( access_t *p_access )
{
    access_sys_t *p_sys = p_access->p_sys;
    block_t *p;

    while ( !p_sys->p_list || 
             ( mdate() - p_sys->p_list->i_pts ) < p_sys->i_rtp_late )
    {
        p = BlockParseRTP( p_access, BlockUDP( p_access ));

        if ( !p ) 
            return NULL;

        rtp_ChainInsert( p_access, p );
    }

    p = p_sys->p_list;
    p_sys->p_list = p_sys->p_list->p_next;
    p_sys->i_last_seqno++;
    if( p_sys->i_last_seqno != (uint16_t) p->i_dts )
    {
        msg_Dbg( p_access, "RTP: packet(s) lost, expected %d, got %d",
                 p_sys->i_last_seqno, (uint16_t) p->i_dts );
        p_sys->i_last_seqno = (uint16_t) p->i_dts;
    }
    p->p_next = NULL;
    return p;
}

/*****************************************************************************
 * BlockChoose: decide between RTP and UDP
 *****************************************************************************/
static block_t *BlockChoose( access_t *p_access )
{
    block_t *p_block;
    int     i_rtp_version;
    int     i_CSRC_count;
    int     i_payload_type;

    if( ( p_block = BlockUDP( p_access ) ) == NULL )
        return NULL;

    if( p_block->p_buffer[0] == 0x47 )
    {
        msg_Dbg( p_access, "detected TS over raw UDP" );
        p_access->pf_block = BlockUDP;
        p_access->info.b_prebuffered = VLC_TRUE;
        return p_block;
    }

    if( p_block->i_buffer < RTP_HEADER_LEN )
        return p_block;

    /* Parse the header and make some verifications.
     * See RFC 3550. */

    i_rtp_version  = ( p_block->p_buffer[0] & 0xC0 ) >> 6;
    i_CSRC_count   = ( p_block->p_buffer[0] & 0x0F );
    i_payload_type = ( p_block->p_buffer[1] & 0x7F );

    if( i_rtp_version != 2 )
    {
        msg_Dbg( p_access, "no supported RTP header detected" );
        p_access->pf_block = BlockUDP;
        p_access->info.b_prebuffered = VLC_TRUE;
        return p_block;
    }

    switch( i_payload_type )
    {
        case 33:
            msg_Dbg( p_access, "detected TS over RTP" );
            p_access->psz_demux = strdup( "ts" );
            break;

        case 14:
            msg_Dbg( p_access, "detected MPEG audio over RTP" );
            p_access->psz_demux = strdup( "mpga" );
            break;

        case 32:
            msg_Dbg( p_access, "detected MPEG video over RTP" );
            p_access->psz_demux = strdup( "mpgv" );
            break;

        default:
            msg_Dbg( p_access, "no RTP header detected" );
            p_access->pf_block = BlockUDP;
            p_access->info.b_prebuffered = VLC_TRUE;
            return p_block;
    }

    if( !BlockParseRTP( p_access, p_block )) return NULL;

    p_access->pf_block = BlockRTP;

    return BlockPrebufferRTP( p_access, p_block );
}