sap.c

VLC Player Source Code

/*****************************************************************************
 * sap.c : SAP announce handler
 *****************************************************************************
 * Copyright (C) 2002-2007 the VideoLAN team
 * $Id: 11bcbc41b8bd6cab255cac188610f7470a293237 $
 *
 * Authors: Clément Stenac <[e-mail]>
 *          Rémi Denis-Courmont <rem # 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>

#include <stdlib.h>                                                /* free() */
#include <stdio.h>                                              /* sprintf() */
#include <string.h>
#include <ctype.h>                                  /* tolower(), isxdigit() */
#include <assert.h>

#include <vlc_sout.h>
#include <vlc_network.h>
#include <vlc_charset.h>

#include "stream_output.h"
#include "libvlc.h"

/* SAP is always on that port */
#define SAP_PORT 9875

#define DEFAULT_PORT "1234"

#undef EXTRA_DEBUG

/* SAP Specific structures */

/* 100ms */
#define SAP_IDLE ((mtime_t)(0.100*CLOCK_FREQ))
#define SAP_MAX_BUFFER 65534
#define MIN_INTERVAL 2
#define MAX_INTERVAL 300

/* A SAP announce address. For each of these, we run the
 * control flow algorithm */
struct sap_address_t
{
    char *psz_address;
    struct sockaddr_storage orig;
    socklen_t origlen;
    int i_rfd; /* Read socket */
    int i_wfd; /* Write socket */

    /* Used for flow control */
    mtime_t t1;
    bool b_enabled;
    bool b_ready;
    int i_interval;
    int i_buff;
    int i_limit;
};

/* A SAP session descriptor, enqueued in the SAP handler queue */
struct sap_session_t {
    uint8_t       *psz_data;
    unsigned      i_length;
    sap_address_t *p_address;
    session_descriptor_t *p_sd;

    /* Last and next send */
    mtime_t        i_last;
    mtime_t        i_next;
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static void * RunThread( vlc_object_t *p_this);
static int ComputeRate( sap_address_t *p_address );

static int announce_SendSAPAnnounce( sap_handler_t *p_sap,
                                     sap_session_t *p_session );


static int announce_SAPAnnounceAdd( sap_handler_t *p_sap,
                             session_descriptor_t *p_session );

static int announce_SAPAnnounceDel( sap_handler_t *p_sap,
                             session_descriptor_t *p_session );

static void announce_SAPHandlerDestructor( vlc_object_t *p_this );


/**
 * Create the SAP handler
 *
 * \param p_announce the parent announce_handler
 * \return the newly created SAP handler or NULL on error
 */
sap_handler_t *announce_SAPHandlerCreate( announce_handler_t *p_announce )
{
    sap_handler_t *p_sap;

    p_sap = vlc_custom_create( VLC_OBJECT(p_announce), sizeof( sap_handler_t ),
                               VLC_OBJECT_ANNOUNCE, "sap announcer" );
    if( !p_sap )
        return NULL;

    p_sap->pf_add = announce_SAPAnnounceAdd;
    p_sap->pf_del = announce_SAPAnnounceDel;

    p_sap->i_sessions = 0;
    p_sap->i_addresses = 0;
    p_sap->i_current_session = 0;

    p_sap->b_control = config_GetInt( p_sap, "sap-flow-control");

    if( vlc_thread_create( p_sap, "sap handler", RunThread,
                       VLC_THREAD_PRIORITY_LOW, false ) )
    {
        msg_Dbg( p_announce, "unable to spawn SAP handler thread");
        vlc_object_release( p_sap );
        return NULL;
    }

    vlc_object_set_destructor( p_sap, announce_SAPHandlerDestructor );

    msg_Dbg( p_announce, "thread created, %i sessions", p_sap->i_sessions);

    return p_sap;
}

static void announce_SAPHandlerDestructor( vlc_object_t * p_this )
{
    sap_handler_t *p_sap = (sap_handler_t *)p_this;
    int i;

    /* Free the remaining sessions */
    for( i = 0 ; i< p_sap->i_sessions ; i++)
    {
        sap_session_t *p_session = p_sap->pp_sessions[i];
        FREENULL( p_session->psz_data );
        REMOVE_ELEM( p_sap->pp_sessions, p_sap->i_sessions , i );
        FREENULL( p_session );
    }

    /* Free the remaining addresses */
    for( i = 0 ; i< p_sap->i_addresses ; i++)
    {
        sap_address_t *p_address = p_sap->pp_addresses[i];
        FREENULL( p_address->psz_address );
        if( p_address->i_rfd > -1 )
        {
            net_Close( p_address->i_rfd );
        }
        if( p_address->i_wfd > -1 && p_sap->b_control )
        {
            net_Close( p_address->i_wfd );
        }
        REMOVE_ELEM( p_sap->pp_addresses, p_sap->i_addresses, i );
        FREENULL( p_address );
    }
}

/**
 * main SAP handler thread
 * \param p_this the SAP Handler object
 * \return nothing
 */
static void * RunThread( vlc_object_t *p_this)
{
    sap_handler_t *p_sap = (sap_handler_t*)p_this;
    sap_session_t *p_session;

    while( !p_sap->b_die )
    {
        int i;

        msleep( SAP_IDLE );

        /* If needed, get the rate info */
        if( p_sap->b_control == true )
        {
            for( i = 0 ; i< p_sap->i_addresses ; i++)
            {
                if( p_sap->pp_addresses[i]->b_enabled == true )
                {
                    ComputeRate( p_sap->pp_addresses[i] );
                }
            }
        }

        /* Find the session to announce */
        vlc_object_lock( p_sap );
        if( p_sap->i_sessions > p_sap->i_current_session + 1)
        {
            p_sap->i_current_session++;
        }
        else if( p_sap->i_sessions > 0)
        {
            p_sap->i_current_session = 0;
        }
        else
        {
            vlc_object_unlock( p_sap );
            continue;
        }
        p_session = p_sap->pp_sessions[p_sap->i_current_session];

        /* And announce it */
        if( p_session->p_address->b_enabled == true &&
            p_session->p_address->b_ready == true )
        {
            announce_SendSAPAnnounce( p_sap, p_session );
        }
        vlc_object_unlock( p_sap );
    }
    return NULL;
}

/* Add a SAP announce */
static int announce_SAPAnnounceAdd( sap_handler_t *p_sap,
                             session_descriptor_t *p_session )
{
    int i;
    char psz_addr[NI_MAXNUMERICHOST];
    bool b_ipv6 = false, b_ssm = false;
    sap_session_t *p_sap_session;
    mtime_t i_hash;
    struct sockaddr_storage addr;
    socklen_t addrlen;

    vlc_object_lock( p_sap );
    addrlen = p_session->addrlen;
    if ((addrlen == 0) || (addrlen > sizeof (addr)))
    {
        vlc_object_unlock( p_sap );
        msg_Err( p_sap, "No/invalid address specified for SAP announce" );
        return VLC_EGENERIC;
    }

    /* Determine SAP multicast address automatically */
    memcpy (&addr, &p_session->addr, addrlen);

    switch( p_session->addr.ss_family )
    {
#if defined (HAVE_INET_PTON) || defined (WIN32)
        case AF_INET6:
        {
            /* See RFC3513 for list of valid IPv6 scopes */
            struct in6_addr *a6 = &((struct sockaddr_in6 *)&addr)->sin6_addr;

            memcpy( a6->s6_addr + 2, "\x00\x00\x00\x00\x00\x00"
                   "\x00\x00\x00\x00\x00\x02\x7f\xfe", 14 );
            if( IN6_IS_ADDR_MULTICAST( a6 ) )
            {
                /* SSM <=> ff3x::/32 */
                b_ssm = (U32_AT (a6->s6_addr) & 0xfff0ffff) == 0xff300000;

                /* force flags to zero, preserve scope */
                a6->s6_addr[1] &= 0xf;
            }
            else
                /* Unicast IPv6 - assume global scope */
                memcpy( a6->s6_addr, "\xff\x0e", 2 );

            b_ipv6 = true;
            break;
        }
#endif

        case AF_INET:
        {
            /* See RFC2365 for IPv4 scopes */
            uint32_t ipv4;

            ipv4 = ntohl( ((struct sockaddr_in *)&addr)->sin_addr.s_addr );
            /* 224.0.0.0/24 => 224.0.0.255 */
            if ((ipv4 & 0xffffff00) == 0xe0000000)
                ipv4 =  0xe00000ff;
            else
            /* 239.255.0.0/16 => 239.255.255.255 */
            if ((ipv4 & 0xffff0000) == 0xefff0000)
                ipv4 =  0xefffffff;
            else
            /* 239.192.0.0/14 => 239.195.255.255 */
            if ((ipv4 & 0xfffc0000) == 0xefc00000)
                ipv4 =  0xefc3ffff;
            else
            if ((ipv4 & 0xff000000) == 0xef000000)
                ipv4 = 0;
            else
            /* other addresses => 224.2.127.254 */
            {
                /* SSM: 232.0.0.0/8 */
                b_ssm = (ipv4 >> 24) == 232;
                ipv4 = 0xe0027ffe;