net_mac.c

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            break;

    }

    return( rcode ) ;
}



/************************************************************************
 *
 *                          NET_MAC_close
 *  Description :
 *  -------------
 *
 *  Close a MAC-SAP.
 *
 *
 *  Parameters :
 *  ------------
 *
 *  mac_sp_hd     service provider defined handle
 *
 *
 *  Return values :
 *  ---------------
 *
 *  'ERROR_NET_MAC_INVALID_HANDLE', invalid handle
 *  'OK'(=0),                       SAP has been closed 
 *
 *
 ************************************************************************/
UINT32 NET_MAC_close( UINT32 mac_sp_hd ) /* service provider defined handle */
{
    /* validate handle */
    IF_UPPER( ERROR_NET_MAC_INVALID_HANDLE, mac_sp_hd, MAC_SAP_COUNT)

    /* close SAP */
    sap_context[mac_sp_hd].mac_sap_state   = MAC_SAP_STATE_CLOSED ;
    sap_context[mac_sp_hd].mac_sap         = MAC_SAP_UNDEFINED ;
    sap_context[mac_sp_hd].mac_usr_receive = NULL ;

    return(OK) ;
}


/************************************************************************
 *
 *                          NET_MAC_send
 *  Description :
 *  -------------
 *
 *  Request the MAC module to send a frame, linked
 *  to a certain 'SAP' to a specified MAC-destination address.
 *
 *
 *  Parameters :
 *  ------------
 *
 *  'mac_sp_hd',           OUT,   handle to lookup a registered SAP context
 *  'dst_adr',             OUT,   destination mac address
 *  'length',              OUT,   length of frame to send
 *  'data',                OUT,   address to start of frame to be send
 *
 *
 *  Return values :
 *  ---------------
 *  'OK'(=0), successfull initialization
 *
 ************************************************************************/
UINT32 NET_MAC_send(  UINT32            mac_sp_hd,       /* service provider defined handle */
                      t_mac_addr        *dst_adr,        /* destination mac address         */
                      UINT32            length,          /* total length of frame to send   */
                      UINT8             *data  )         /* pointer to start of frame       */
{
    UINT32  old_ie ;
    t_LAN_IO_desc desc ;
    UINT32        rcode ;
    UINT8         *p ;
    UINT16        sap ;

    /* validate handle */
    IF_UPPER( ERROR_NET_MAC_INVALID_HANDLE, mac_sp_hd, MAC_SAP_COUNT)

    /* validate state */
    if ( sap_context[mac_sp_hd].mac_sap_state != MAC_SAP_STATE_OPEN )
    {
        return( ERROR_NET_MAC_SAP_CLOSED ) ;
    }

    /* we have a registered SAP context */
    sap = sap_context[mac_sp_hd].mac_sap ; /* get SAP (in 'BE' format) */

    /* Fill-in MAC header of frame */
    p = (data + MAC_HEADER_BASE) ;
    put6( dst_adr[0], p ) ;         /* fill-in destination MAC-address */
    put6( mac_station_adr[0], p ) ; /* fill-in our MAC-address         */
    put2( sap, p ) ;                /* fill-in SAP                     */

#ifdef NET_DEBUG
    {
        int i ;
        p = data ;
        printf("NET_MAC_send:") ;
        for (i=0; i<length; i++)
        {
            if (i%16 == 0)
            {
                printf("\n %02x",*p++ ) ;
            }
            else
            {
                printf(" %02x",*p++ ) ;
            }
        }
        printf("\n" ) ;
    }
#endif

    /* Check for broadcast */
    if ( !memcmp( data, mac_broadcast_adr, SYS_MAC_ADDR_SIZE ) )
    {
        /* This is for our station; i.e. loopback */
        old_ie = sys_disable_int() ;
        memcpy( lbbuf, data, length ) ;
        rcode = NET_MAC_receive( length, lbbuf ) ;
        if(old_ie) sys_enable_int();
    }

    /* Check for loopback */
    if ( !memcmp( data, mac_station_adr,   SYS_MAC_ADDR_SIZE ) )
    {
        /* This is for our station; i.e. loopback */
        old_ie = sys_disable_int() ;
        memcpy( lbbuf, data, length ) ;
        rcode = NET_MAC_receive( length, lbbuf ) ;
        if(old_ie) sys_enable_int();
    }
    else
    {
        /* Call driver to send this frame */
        desc.length = length ;
        desc.data   = data ;
        rcode = IO_write( en0_major_device, 0, &desc )  ;
    }

    /* return completion */
    return( rcode ) ;
}


/************************************************************************
 *
 *                          NET_MAC_poll
 *  Description :
 *  -------------
 *  Poll the MAC module to receive any frame from driver.
 *  (Note: is not used by ISR-handled reception.)
 *
 *
 *  Parameters :
 *  ------------
 *  -
 *
 *
 *  Return values :
 *  ---------------
 *  'OK'
 *
 ************************************************************************/
UINT32 NET_MAC_poll(  void )
{
    UINT32 rcode ;
    t_LAN_IO_desc desc ;

    /* we just call the driver to poll and let the driver
       call 'NET_MAC_receive' in case of any received frame             */
    desc.length = 0 ;
    desc.data   = NULL ;
    rcode = IO_read( en0_major_device, 0, &desc )  ;
    return( rcode ) ;
}


/************************************************************************
 *      Implementation : Static functions
 ************************************************************************/


/************************************************************************
 *
 *                          NET_MAC_receive
 *  Description :
 *  -------------
 *  In "RX-frame receive int. mode", this function is called from 
 *  the LAN-driver ISR, whenever it receives an Ethernet frame. 
 *
 *  In "RX-frame receive polled mode", this function will still
 *  be called from the LAN-driver, but in this case, the call
 *  gets started when NET_MAC_poll() calls the LAN-driver 'read'
 *  entry.
 *
 *  It must check for any SAP's registered to handle the addressed
 *  SAP and if one found, the registered receive handler is called.
 *
 *
 *
 *  Parameters :
 *  ------------
 *  'length':  length of received ethernet frame
 *  'data':    pointer for received ethernet frame (in driver's space)
 *
 *
 *  Return values :
 *  ---------------
 *  'OK' 
 *
 ************************************************************************/
static 
UINT32 NET_MAC_receive( UINT32 length,
                        UINT8  *data    )
{
    UINT32            rcode ;
    t_mac_usr_receive receive ;
    UINT8             *p ;
    UINT16            sap ;
    int               i ;

#ifdef NET_DEBUG
    p = data ;
    printf("NET_MAC_receive:") ;
    for (i=0; i<length; i++)
    {
        if (i%16 == 0)
        {
            printf("\n %02x",*p++ ) ;
        }
        else
        {
            printf(" %02x",*p++ ) ;
        }
    }
    printf("\n" ) ;
#endif

    /* validate frame size */
    if (length > MAC_MAX_FRAME_SIZE)
    {
        return( ERROR_NET_MAC_INVALID_LENGTH ) ;
    }

    /* get sap of this received frame, and keep it in 'BE'-format */
    p = (data + MAC_HEADER_BASE + MAC_HEADER_TYPE) ;
    get2( p, sap) ;


    /* search the SAP table to match this 'sap' */
    for ( i = 0; i <MAC_SAP_COUNT ; i++ )
    {
        if ( sap_context[i].mac_sap == sap )
        {
            if ( sap_context[i].mac_sap_state == MAC_SAP_STATE_OPEN )
            {
                /* we have a registered SAP context, call user */
                receive    = sap_context[i].mac_usr_receive ;
                p = (data + MAC_HEADER_BASE + MAC_HEADER_SRCADR) ;
                rcode = (*receive)( (t_mac_addr*) p,
                                    length,
                                    data ) ;
#ifdef NET_DEBUG
                printf("NET_MAC_receive, rcode = %x\n", rcode ) ;
#endif

                return( rcode ) ;
            }
        }
    }
    return( ERROR_NET_MAC_NO_SAP ) ;
}


/************************************************************************
 *
 *                          NET_MAC_alloc_sap
 *  Description :
 *  -------------
 *  Allocate a MAC SAP, register user context and return a sp-handle.
 * 
 *
 *  Parameters :
 *  ------------
 *  'mac_sap_id',          IN,    value of MAC-'type' to bind for
 *  'mac_usr_receive',     IN,    user-receive function to be registered
 *  'mac_sp_hd',           OUT,   handle of MAC to be used by user by call
 *                                of 'send'
 *
 *
 *  Return values :
 *  ---------------
 * 'ERROR_NET_MAC_NO_FREE_SAP', No SAP entry could be allocated
 * 'OK' = 0x00: 
 *
 *
 ************************************************************************/
static
UINT32 NET_MAC_alloc_sap(
                      UINT16            mac_sap_id,      /* 'type'-field of mac-header
                                                            always in 'cpu' format          */
                      t_mac_usr_receive mac_usr_receive, /* user defined receive handler    */ 
                      UINT32            *mac_sp_hd )     /* service provider defined handle */
{
    int i ;

    /* allocate a free MAC SAP table entry */
    for ( i = 0; i <MAC_SAP_COUNT ; i++)
    {
        if ( sap_context[i].mac_sap_state == MAC_SAP_STATE_CLOSED )
        {
            /* save SAP context in allocated entry */
            sap_context[i].mac_sap_state   = MAC_SAP_STATE_OPEN ;
            sap_context[i].mac_sap         = CPU_TO_BE16( mac_sap_id ) ;
            sap_context[i].mac_usr_receive = mac_usr_receive ;
            *mac_sp_hd                     = i ;
            return( OK ) ;
        }
    }

    /* we should not arrive here */
    return( ERROR_NET_MAC_NO_FREE_SAP ) ;
}