sap.c

uclinux 下的vlc播放器源代码

        msg_Err( p_sap, "%s", vlc_gai_strerror( i ) );
        return VLC_EGENERIC;
    }

    msg_Dbg( p_sap, "using SAP address: %s", psz_addr);

    /* XXX: Check for dupes */
    p_sap_session = (sap_session_t*)malloc(sizeof(sap_session_t));
    p_sap_session->p_address = NULL;

    /* Add the address to the buffer */
    for( i = 0; i < p_sap->i_addresses; i++)
    {
        if( !strcmp( psz_addr, p_sap->pp_addresses[i]->psz_address ) )
        {
            p_sap_session->p_address = p_sap->pp_addresses[i];
            break;
        }
    }

    if( p_sap_session->p_address == NULL )
    {
        sap_address_t *p_address = (sap_address_t *)
                                    malloc( sizeof(sap_address_t) );
        if( !p_address )
        {
            msg_Err( p_sap, "out of memory" );
            return VLC_ENOMEM;
        }
        p_address->psz_address = strdup( psz_addr );
        p_address->i_wfd = net_ConnectUDP( p_sap, psz_addr, SAP_PORT, 255 );
        if( p_address->i_wfd != -1 )
        {
            char *ptr;

            net_StopRecv( p_address->i_wfd );
            net_GetSockAddress( p_address->i_wfd, p_address->psz_machine,
                                NULL );

            /* removes scope if present */
            ptr = strchr( p_address->psz_machine, '%' );
            if( ptr != NULL )
                *ptr = '\0';
        }

        if( p_sap->b_control == VLC_TRUE )
        {
            p_address->i_rfd = net_OpenUDP( p_sap, psz_addr, SAP_PORT, "", 0 );
            if( p_address->i_rfd != -1 )
                net_StopSend( p_address->i_rfd );
            p_address->i_buff = 0;
            p_address->b_enabled = VLC_TRUE;
            p_address->b_ready = VLC_FALSE;
            p_address->i_limit = 10000; /* 10000 bps */
            p_address->t1 = 0;
        }
        else
        {
            p_address->b_enabled = VLC_TRUE;
            p_address->b_ready = VLC_TRUE;
            p_address->i_interval = config_GetInt( p_sap,"sap-interval");
            p_address->i_rfd = -1;
        }

        if( p_address->i_wfd == -1 || (p_address->i_rfd == -1
                                        && p_sap->b_control ) )
        {
            msg_Warn( p_sap, "disabling address" );
            p_address->b_enabled = VLC_FALSE;
        }

        INSERT_ELEM( p_sap->pp_addresses,
                     p_sap->i_addresses,
                     p_sap->i_addresses,
                     p_address );
        p_sap_session->p_address = p_address;
    }


    /* Build the SAP Headers */
    i_header_size = ( b_ipv6 ? 16 : 4 ) + 20;
    psz_head = (char *) malloc( i_header_size * sizeof( char ) );
    if( psz_head == NULL )
    {
        msg_Err( p_sap, "out of memory" );
        return VLC_ENOMEM;
    }

    /* SAPv1, not encrypted, not compressed */
    psz_head[0] = b_ipv6 ? 0x30 : 0x20;
    psz_head[1] = 0x00; /* No authentification length */

    i_hash = mdate();
    psz_head[2] = (i_hash & 0xFF00) >> 8; /* Msg id hash */
    psz_head[3] = (i_hash & 0xFF);        /* Msg id hash 2 */

#if defined (HAVE_INET_PTON) || defined (WIN32)
    if( b_ipv6 )
    {
        inet_pton( AF_INET6, /* can't fail */
                   p_sap_session->p_address->psz_machine,
                   psz_head + 4 );
    }
    else
#endif
    {
        inet_pton( AF_INET, /* can't fail */
                   p_sap_session->p_address->psz_machine,
                   psz_head + 4 );
    }

    memcpy( psz_head + (b_ipv6 ? 20 : 8), "application/sdp", 15 );

    /* If needed, build the SDP */
    if( p_session->psz_sdp == NULL )
    {
        p_session->psz_sdp = SDPGenerate( p_sap, p_session,
                                          p_sap_session->p_address, b_ssm );
        if( p_session->psz_sdp == NULL )
        {
            vlc_mutex_unlock( &p_sap->object_lock );
            return VLC_ENOMEM;
        }
    }

    p_sap_session->psz_sdp = strdup( p_session->psz_sdp );
    p_sap_session->i_last = 0;

    psz_head[ i_header_size-1 ] = '\0';
    p_sap_session->i_length = i_header_size + strlen( p_sap_session->psz_sdp);

    p_sap_session->psz_data = (uint8_t *)malloc( sizeof(char)*
                                                 p_sap_session->i_length );

    /* Build the final message */
    memcpy( p_sap_session->psz_data, psz_head, i_header_size );
    memcpy( p_sap_session->psz_data+i_header_size, p_sap_session->psz_sdp,
            strlen( p_sap_session->psz_sdp) );

    free( psz_head );

    /* Enqueue the announce */
    INSERT_ELEM( p_sap->pp_sessions,
                 p_sap->i_sessions,
                 p_sap->i_sessions,
                 p_sap_session );
    msg_Dbg( p_sap,"%i addresses, %i sessions",
                   p_sap->i_addresses,p_sap->i_sessions);

    /* Remember the SAP session for later deletion */
    p_session->p_sap = p_sap_session;

    vlc_mutex_unlock( &p_sap->object_lock );

    return VLC_SUCCESS;
}

/* Remove a SAP Announce */
static int announce_SAPAnnounceDel( sap_handler_t *p_sap,
                             session_descriptor_t *p_session )
{
    int i;
    vlc_mutex_lock( &p_sap->object_lock );

    msg_Dbg( p_sap,"removing SAP announce %p",p_session->p_sap);

    /* Dequeue the announce */
    for( i = 0; i< p_sap->i_sessions; i++)
    {
        if( p_session->p_sap == p_sap->pp_sessions[i] )
        {
            REMOVE_ELEM( p_sap->pp_sessions,
                         p_sap->i_sessions,
                         i );

            FREE( p_session->p_sap->psz_sdp );
            FREE( p_session->p_sap->psz_data );
            free( p_session->p_sap );
            break;
        }
    }

    /* XXX: Dequeue the address too if it is not used anymore
     * TODO: - address refcount
             - send a SAP deletion packet */

    msg_Dbg( p_sap,"%i announcements remaining", p_sap->i_sessions );

    vlc_mutex_unlock( &p_sap->object_lock );

    return VLC_SUCCESS;
}

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

    /* This announce has never been sent yet */
    if( p_session->i_last == 0 )
    {
        p_session->i_next = mdate()+ p_session->p_address->i_interval*1000000;
        p_session->i_last = 1;
        return VLC_SUCCESS;
    }

    if( p_session->i_next < mdate() )
    {
#ifdef EXTRA_DEBUG
        msg_Dbg( p_sap, "sending announce");
#endif
        i_ret = net_Write( p_sap, p_session->p_address->i_wfd, NULL,
                           p_session->psz_data,
                           p_session->i_length );
        if( i_ret != (int)p_session->i_length )
        {
            msg_Warn( p_sap, "SAP send failed on address %s (%i %i)",
                      p_session->p_address->psz_address,
                      i_ret, p_session->i_length );
        }
        p_session->i_last = p_session->i_next;
        p_session->i_next = p_session->i_last
                            + p_session->p_address->i_interval*1000000;
    }
    else
    {
        return VLC_SUCCESS;
    }
    return VLC_SUCCESS;
}

static char *SDPGenerate( sap_handler_t *p_sap,
                          const session_descriptor_t *p_session,
                          const sap_address_t *p_addr, vlc_bool_t b_ssm )
{
    int64_t i_sdp_id = mdate();
    int     i_sdp_version = 1 + p_sap->i_sessions + (rand()&0xfff);
    char *psz_group, *psz_name, psz_uribuf[NI_MAXNUMERICHOST], *psz_uri,
         *psz_sdp;
    char ipv;
    char *sfilter = NULL;
    int res;

    psz_group = p_session->psz_group;
    psz_name = p_session->psz_name;

    /* FIXME: really check that psz_uri is a real IP address
     * FIXME: make a common function to obtain a canonical IP address */
    ipv = ( strchr( p_session->psz_uri, ':' )  != NULL) ? '6' : '4';
    if( *p_session->psz_uri == '[' )
    {
        char *ptr;

        strlcpy( psz_uribuf, p_session->psz_uri + 1, sizeof( psz_uribuf ) );
        ptr = strchr( psz_uribuf, '%' );
        if( ptr != NULL)
            *ptr = '\0';
        ptr = strchr( psz_uribuf, ']' );
        if( ptr != NULL)
            *ptr = '\0';
        psz_uri = psz_uribuf;
    }
    else
        psz_uri = p_session->psz_uri;

    if (b_ssm)
    {
        if (asprintf (&sfilter, "a=source-filter: incl IN IP%c * %s\r\n",
                      ipv, p_addr->psz_machine) == -1)
            return NULL;
    }

    /* see the lists in modules/stream_out/rtp.c for compliance stuff */
    res = asprintf (&psz_sdp,
                        "v=0\r\n"
                        "o=- "I64Fd" %d IN IP%c %s\r\n"
                        "s=%s\r\n"
                        "c=IN IP%c %s%s\r\n"
                        "t=0 0\r\n"
                        "a=tool:"PACKAGE_STRING"\r\n"
                        "a=recvonly\r\n"
                        "a=type:broadcast\r\n"
                        "%s"
                        "%s%s%s"
                        "m=video %d %s %d\r\n",
                        i_sdp_id, i_sdp_version,
                        ipv, p_addr->psz_machine,
                        psz_name, ipv, psz_uri,
                        (ipv == 4) ? "/255" : "",
                        (sfilter != NULL) ? sfilter : "",
                        psz_group ? "a=x-plgroup:" : "",
                        psz_group ? psz_group : "", psz_group ? "\r\n" : "",
                        p_session->i_port,
                        p_session->b_rtp ? "RTP/AVP" : "udp",
                        p_session->i_payload);
    if (sfilter != NULL)
        free (sfilter);

    if (res == -1)
        return NULL;

    msg_Dbg( p_sap, "Generated SDP (%i bytes):\n%s", strlen(psz_sdp),
             psz_sdp );
    return psz_sdp;
}

static int CalculateRate( sap_handler_t *p_sap, sap_address_t *p_address )
{
    int i_read;
    uint8_t buffer[SAP_MAX_BUFFER];
    int i_tot = 0;
    mtime_t i_temp;
    int i_rate;

    if( p_address->t1 == 0 )
    {
        p_address->t1 = mdate();
        return VLC_SUCCESS;
    }
    do
    {
        /* Might be too slow if we have huge data */
        i_read = net_ReadNonBlock( p_sap, p_address->i_rfd, NULL, buffer,
                                   SAP_MAX_BUFFER, 0 );
        i_tot += i_read;
    } while( i_read > 0 && i_tot < SAP_MAX_BUFFER );

    i_temp = mdate();

    /* We calculate the rate every 5 seconds */
    if( i_temp - p_address->t1 < 5000000 )
    {
        p_address->i_buff += i_tot;
        return VLC_SUCCESS;
    }

    /* Bits/second */
    i_rate = (int)(8*1000000*((mtime_t)p_address->i_buff + (mtime_t)i_tot ) /
                        (i_temp - p_address->t1 ));

    p_address->i_limit = 10000;

    p_address->i_interval = ((1000*i_rate / p_address->i_limit) *
                            (MAX_INTERVAL - MIN_INTERVAL))/1000 + MIN_INTERVAL;

    if( p_address->i_interval > MAX_INTERVAL || p_address->i_interval < 0 )
    {
        p_address->i_interval = MAX_INTERVAL;
    }
#ifdef EXTRA_DEBUG
    msg_Dbg( p_sap,"%s:%i: rate=%i, interval = %i s",
             p_address->psz_address,SAP_PORT, i_rate, p_address->i_interval );
#endif

    p_address->b_ready = VLC_TRUE;

    p_address->t1 = i_temp;
    p_address->i_buff = 0;

    return VLC_SUCCESS;
}