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/*

 * Copyright (c) 2009 Lukas Mejdrech

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup eth

 *  @{

 */

/** @file

 *  Ethernet module implementation.

 *  @see eth.h

 */

#include <async.h>

#include <malloc.h>

#include <mem.h>

#include <stdio.h>

#include <ipc/ipc.h>

#include <ipc/services.h>

#include "../../err.h"

#include "../../messages.h"

#include "../../modules.h"

#include "../../include/byteorder.h"

#include "../../include/crc.h"

#include "../../include/ethernet_lsap.h"

#include "../../include/ethernet_protocols.h"

#include "../../include/protocol_map.h"

#include "../../include/device.h"

#include "../../include/netif_interface.h"

#include "../../include/net_interface.h"

#include "../../include/nil_interface.h"

#include "../../include/il_interface.h"

#include "../../structures/measured_strings.h"

#include "../../structures/packet/packet_client.h"

#include "../nil_module.h"

#include "eth.h"

#include "eth_header.h"

/** Reserved packet prefix length.

 */

#define ETH_PREFIX      ( sizeof( eth_header_t ) + sizeof( eth_header_lsap_t ) + sizeof( eth_header_snap_t ))

/** Reserved packet suffix length.

 */

#define ETH_SUFFIX      sizeof( eth_fcs_t )

/** Maximum packet content length.

 */

#define ETH_MAX_CONTENT 1500

/** Minimum packet content length.

 */

#define ETH_MIN_CONTENT 46

/** Maximum tagged packet content length.

 */

#define ETH_MAX_TAGGED_CONTENT( flags ) ( ETH_MAX_CONTENT - (( IS_8023_2_LSAP( flags ) || IS_8023_2_SNAP( flags )) ? sizeof( eth_header_lsap_t ) : 0 ) - ( IS_8023_2_SNAP( flags ) ? sizeof( eth_header_snap_t ) : 0 ))

/** Minimum tagged packet content length.

 */

#define ETH_MIN_TAGGED_CONTENT( flags ) ( ETH_MIN_CONTENT - (( IS_8023_2_LSAP( flags ) || IS_8023_2_SNAP( flags )) ? sizeof( eth_header_lsap_t ) : 0 ) - ( IS_8023_2_SNAP( flags ) ? sizeof( eth_header_snap_t ) : 0 ))

/** Dummy flag shift value.

 */

#define ETH_DUMMY_SHIFT 0

/** Mode flag shift value.

 */

#define ETH_MODE_SHIFT  1

/** Dummy device flag.

 *  Preamble and FCS are mandatory part of the packets.

 */

#define ETH_DUMMY               ( 1 << ETH_DUMMY_SHIFT )

/** Returns the dummy flag.

 *  @see ETH_DUMMY

 */

#define IS_DUMMY( flags )       (( flags ) & ETH_DUMMY )

/** Device mode flags.

 *  @see ETH_DIX

 *  @see ETH_8023_2_LSAP

 *  @see ETH_8023_2_SNAP

 */

#define ETH_MODE_MASK           ( 3 << ETH_MODE_SHIFT )

/** DIX Ethernet mode flag.

 */

#define ETH_DIX                 ( 1 << ETH_MODE_SHIFT )

/** Returns whether the DIX Ethernet mode flag is set.

 *  @param flags The ethernet flags. Input parameter.

 *  @see ETH_DIX

 */

#define IS_DIX( flags )         ((( flags ) & ETH_MODE_MASK ) == ETH_DIX )

/** 802.3 + 802.2 + LSAP mode flag.

 */

#define ETH_8023_2_LSAP         ( 2 << ETH_MODE_SHIFT )

/** Returns whether the 802.3 + 802.2 + LSAP mode flag is set.

 *  @param flags The ethernet flags. Input parameter.

 *  @see ETH_8023_2_LSAP

 */

#define IS_8023_2_LSAP( flags ) ((( flags ) & ETH_MODE_MASK ) == ETH_8023_2_LSAP )

/** 802.3 + 802.2 + LSAP + SNAP mode flag.

 */

#define ETH_8023_2_SNAP         ( 3 << ETH_MODE_SHIFT )

/** Returns whether the 802.3 + 802.2 + LSAP + SNAP mode flag is set.

 *  @param flags The ethernet flags. Input parameter.

 *  @see ETH_8023_2_SNAP

 */

#define IS_8023_2_SNAP( flags ) ((( flags ) & ETH_MODE_MASK ) == ETH_8023_2_SNAP )

/** Type definition of the ethernet address type.

 *  @see eth_addr_type

 */

typedef enum eth_addr_type  eth_addr_type_t;

/** Type definition of the ethernet address type pointer.

 *  @see eth_addr_type

 */

typedef eth_addr_type_t *   eth_addr_type_ref;

/** Ethernet address type.

 */

enum eth_addr_type{

    /** Local address.

     */

    ETH_LOCAL_ADDR,

    /** Broadcast address.

     */

    ETH_BROADCAST_ADDR

};

/** Ethernet module global data.

 */

eth_globals_t   eth_globals;

/** Processes IPC messages from the registered device driver modules in an infinite loop.

 *  @param iid The message identifier. Input parameter.

 *  @param icall The message parameters. Input/output parameter.

 */

void    eth_receiver( ipc_callid_t iid, ipc_call_t * icall );

/** Registers new device or updates the MTU of an existing one.

 *  Determines the device local hardware address.

 *  @param device_id The new device identifier. Input parameter.

 *  @param service The device driver service. Input parameter.

 *  @param mtu The device maximum transmission unit. Input parameter.

 *  @returns EOK on success.

 *  @returns EEXIST if the device with the different service exists.

 *  @returns ENOMEM if there is not enough memory left.

 *  @returns Other error codes as defined for the net_get_device_conf_req() function.

 *  @returns Other error codes as defined for the netif_bind_service() function.

 *  @returns Other error codes as defined for the netif_get_addr() function.

 */

int eth_device_message( device_id_t device_id, services_t service, size_t mtu );

/** Registers receiving module service.

 *  Passes received packets for this service.

 *  @param service The module service. Input parameter.

 *  @param phone The service phone. Input parameter.

 *  @returns EOK on success.

 *  @returns ENOENT if the service is not known.

 *  @returns ENOMEM if there is not enough memory left.

 */

int nil_register_message( services_t service, int phone );

/** Returns the device packet dimensions for sending.

 *  @param device_id The device identifier. Input parameter.

 *  @param addr_len The minimum reserved address length. Output parameter.

 *  @param prefix The minimum reserved prefix size. Output parameter.

 *  @param content The maximum content size. Output parameter.

 *  @param suffix The minimum reserved suffix size. Output parameter.

 *  @returns EOK on success.

 *  @returns EBADMEM if either one of the parameters is NULL.

 *  @returns ENOENT if there is no such device.

 */

int eth_packet_space_message( device_id_t device_id, size_t * addr_len, size_t * prefix, size_t * content, size_t * suffix );

/** Returns the device hardware address.

 *  @param device_id The device identifier. Input parameter.

 *  @param type Type of the desired address. Input parameter

 *  @param address The device hardware address. Output parameter.

 *  @returns EOK on success.

 *  @returns EBADMEM if the address parameter is NULL.

 *  @returns ENOENT if there no such device.

 */

int eth_addr_message( device_id_t device_id, eth_addr_type_t type, measured_string_ref * address );

/** Sends the packet queue.

 *  Sends only packet successfully processed by the eth_prepare_packet() function.

 *  @param device_id The device identifier. Input parameter.

 *  @param packet The packet queue. Input parameter.

 *  @param sender The sending module service. Input parameter.

 *  @returns EOK on success.

 *  @returns ENOENT if there no such device.

 *  @returns EINVAL if the service parameter is not known.

 */

int eth_send_message( device_id_t device_id, packet_t packet, services_t sender );

/** Processes the received packet and chooses the target registered module.

 *  @param flags The device flags. Input parameter.

 *  @param packet The packet. Input parameter.

 *  @returns The target registered module.

 *  @returns NULL if the packet is not long enough.

 *  @returns NULL if the packet is too long.

 *  @returns NULL if the raw ethernet protocol is used.

 *  @returns NULL if the dummy device FCS checksum is invalid.

 *  @returns NULL if the packet address length is not big enough.

 */

eth_proto_ref   eth_process_packet( int flags, packet_t packet );

/** Prepares the packet for sending.

 *  @param flags The device flags. Input parameter.

 *  @param packet The packet. Input parameter.

 *  @param src_addr The source hardware address. Input parameter.

 *  @param ethertype The ethernet protocol type. Input parameter.

 *  @param mtu The device maximum transmission unit. Input parameter.

 *  @returns EOK on success.

 *  @returns EINVAL if the packet addresses length is not long enough.

 *  @returns EINVAL if the packet is bigger than the device MTU.

 *  @returns ENOMEM if there is not enough memory in the packet.

 */

int eth_prepare_packet( int flags, packet_t packet, uint8_t * src_addr, int ethertype, size_t mtu );

DEVICE_MAP_IMPLEMENT( eth_devices, eth_device_t )

INT_MAP_IMPLEMENT( eth_protos, eth_proto_t )

int nil_device_state_msg( int nil_phone, device_id_t device_id, int state ){

    int             index;

    eth_proto_ref   proto;

    //TODO clear device if off?

    rwlock_read_lock( & eth_globals.protos_lock );

    for( index = eth_protos_count( & eth_globals.protos ) - 1; index >= 0; -- index ){

        proto = eth_protos_get_index( & eth_globals.protos, index );

        if( proto && proto->phone ) il_device_state_msg( proto->phone, device_id, state, proto->service );

    }

    rwlock_read_unlock( & eth_globals.protos_lock );

    return EOK;

}

int nil_initialize( int net_phone ){

    ERROR_DECLARE;

    rwlock_initialize( & eth_globals.devices_lock );

    rwlock_initialize( & eth_globals.protos_lock );

    rwlock_write_lock( & eth_globals.devices_lock );

    rwlock_write_lock( & eth_globals.protos_lock );

    eth_globals.net_phone = net_phone;

    eth_globals.broadcast_addr = measured_string_create_bulk( "\xFF\xFF\xFF\xFF\xFF\xFF", CONVERT_SIZE( uint8_t, char, ETH_ADDR ));

    if( ! eth_globals.broadcast_addr ) return ENOMEM;

    ERROR_PROPAGATE( eth_devices_initialize( & eth_globals.devices ));

    if( ERROR_OCCURRED( eth_protos_initialize( & eth_globals.protos ))){

        eth_devices_destroy( & eth_globals.devices );

        return ERROR_CODE;

    }

    rwlock_write_unlock( & eth_globals.protos_lock );

    rwlock_write_unlock( & eth_globals.devices_lock );

    return EOK;

}

int eth_device_message( device_id_t device_id, services_t service, size_t mtu ){

    ERROR_DECLARE;

    eth_device_ref  device;

    int             index;

    measured_string_t   names[ 2 ] = {{ "ETH_MODE", 8 }, { "ETH_DUMMY", 9 }};

    measured_string_ref configuration;

    size_t              count = sizeof( names ) / sizeof( measured_string_t );

    char *              data;

    rwlock_write_lock( & eth_globals.devices_lock );

    // an existing device?

    device = eth_devices_find( & eth_globals.devices, device_id );

    if( device ){

        if( device->service != service ){

            printf( "Device %d already exists\n", device->device_id );

            rwlock_write_unlock( & eth_globals.devices_lock );

            return EEXIST;

        }else{

            // update mtu

            device->mtu = mtu;

            printf( "Device %d already exists:\tMTU\t= %d\n", device->device_id, device->mtu );

        }

    }else{

        // create a new device

        device = ( eth_device_ref ) malloc( sizeof( eth_device_t ));

        if( ! device ) return ENOMEM;

        device->device_id = device_id;

        device->service = service;

        device->flags = 0;

        device->mtu = (( mtu > 0 ) && ( mtu <= ETH_MAX_TAGGED_CONTENT( device->flags ))) ? mtu : ETH_MAX_TAGGED_CONTENT( device->flags );

        configuration = & names[ 0 ];

        if( ERROR_OCCURRED( net_get_device_conf_req( eth_globals.net_phone, device->device_id, & configuration, count, & data ))){

            rwlock_write_unlock( & eth_globals.devices_lock );

            free( device );

            return ERROR_CODE;

        }

        if( configuration ){

            if( ! str_lcmp( configuration[ 0 ].value, "DIX", configuration[ 0 ].length )){

                device->flags |= ETH_DIX;

            }else if( ! str_lcmp( configuration[ 0 ].value, "8023_2_LSAP", configuration[ 0 ].length )){

                // TODO 8023_2_LSAP

                printf( "8023_2_LSAP is not supported (yet?), DIX used instead\n" );

                device->flags |= ETH_DIX;

            }else device->flags |= ETH_8023_2_SNAP;

            if(( configuration[ 1 ].value ) && ( configuration[ 1 ].value[ 0 ] == 'y' )){

                device->flags |= ETH_DUMMY;

            }

            net_free_settings( configuration, data );

        }else{

            device->flags |= ETH_8023_2_SNAP;

        }

        // bind the device driver

        device->phone = netif_bind_service( device->service, device->device_id, SERVICE_ETHERNET, eth_receiver );

        if( device->phone < 0 ){

            rwlock_write_unlock( & eth_globals.devices_lock );

            free( device );

            return device->phone;

        }

        // get hardware address

        if( ERROR_OCCURRED( netif_get_addr( device->phone, device->device_id, & device->addr, & device->addr_data ))){

            rwlock_write_unlock( & eth_globals.devices_lock );

            free( device );

            return ERROR_CODE;

        }

        // add to the cache

        index = eth_devices_add( & eth_globals.devices, device->device_id, device );

        if( index < 0 ){

            rwlock_write_unlock( & eth_globals.devices_lock );

            free( device->addr );

            free( device->addr_data );

            free( device );

            return index;

        }

        printf( "New device registered:\n\tid\t= %d\n\tservice\t= %d\n\tMTU\t= %d\n\taddress\t= %X:%X:%X:%X:%X:%X\n\tflags\t= 0x%x\n", device->device_id, device->service, device->mtu, device->addr_data[ 0 ], device->addr_data[ 1 ], device->addr_data[ 2 ], device->addr_data[ 3 ], device->addr_data[ 4 ], device->addr_data[ 5 ], device->flags );

    }

    rwlock_write_unlock( & eth_globals.devices_lock );

    return EOK;

}

eth_proto_ref eth_process_packet( int flags, packet_t packet ){

    ERROR_DECLARE;

    eth_header_ex_ref   header;

    size_t              length;

    int                 type;

    size_t              prefix;

    size_t              suffix;

    eth_fcs_ref         fcs;

    length = packet_get_data_length( packet );

    if( IS_DUMMY( flags )){

        packet_trim( packet, sizeof( eth_preamble_t ), 0 );

    }

    if( length < sizeof( eth_header_t ) + ETH_MIN_CONTENT + ( IS_DUMMY( flags ) ? ETH_SUFFIX : 0 )) return NULL;

    header = ( eth_header_ex_ref ) packet_get_data( packet );

    type = ntohs( header->header.ethertype );

    if( type >= ETH_MIN_PROTO ){

        // DIX Ethernet

        prefix = sizeof( eth_header_t );

        suffix = 0;

        fcs = (( void * ) header ) + length - sizeof( eth_fcs_t );

    }else if( type <= ETH_MAX_CONTENT ){

        // translate "LSAP" values

        if(( header->lsap.dsap == ETH_LSAP_GLSAP ) && ( header->lsap.ssap == ETH_LSAP_GLSAP )){

            // raw packet

            // discard

            return NULL;

        }else if(( header->lsap.dsap == ETH_LSAP_SNAP ) && ( header->lsap.ssap == ETH_LSAP_SNAP )){

            // IEEE 802.3 + 802.2 + LSAP + SNAP

            // organization code not supported

            type = ntohs( header->snap.ethertype );

            prefix = sizeof( eth_header_t ) + sizeof( eth_header_lsap_t ) + sizeof( eth_header_snap_t );

        }else{

            // IEEE 802.3 + 802.2 LSAP

            type = lsap_map( header->lsap.dsap );

            prefix = sizeof( eth_header_t ) + sizeof( eth_header_lsap_t);

        }

        suffix = ( type < ETH_MIN_CONTENT ) ? ETH_MIN_CONTENT - type : 0;

        fcs = (( void * ) header ) + prefix + type + suffix;

        suffix += length - prefix - type;

    }else{

        // invalid length/type, should not occurr

        return NULL;

    }

    if( IS_DUMMY( flags )){

        if(( ~ compute_crc32( ~ 0, & header->header.dest, ((( void * ) fcs ) - (( void * ) & header->header.dest )) * 8 )) != ntohl( * fcs )){

            return NULL;

        }

        suffix += sizeof( eth_fcs_t );

    }

    if( ERROR_OCCURRED( packet_set_addr( packet, header->header.src, header->header.dest, ETH_ADDR ))

    || ERROR_OCCURRED( packet_trim( packet, prefix, suffix ))){

        return NULL;

    }

    return eth_protos_find( & eth_globals.protos, type );

}

int nil_received_msg( int nil_phone, device_id_t device_id, packet_t packet, services_t target ){

    eth_proto_ref   proto;

    packet_t        next;

    eth_device_ref  device;

    int             flags;

    rwlock_read_lock( & eth_globals.devices_lock );

    device = eth_devices_find( & eth_globals.devices, device_id );

    if( ! device ){

        rwlock_read_unlock( & eth_globals.devices_lock );

        return ENOENT;

    }

    flags = device->flags;

    rwlock_read_unlock( & eth_globals.devices_lock );

    rwlock_read_lock( & eth_globals.protos_lock );

    do{

        next = pq_detach( packet );

        proto = eth_process_packet( flags, packet );

        if( proto ){

            il_received_msg( proto->phone, device_id, packet, proto->service );

        }else{

            // drop invalid/unknown

            pq_release( eth_globals.net_phone, packet_get_id( packet ));

        }

        packet = next;

    }while( packet );

    rwlock_read_unlock( & eth_globals.protos_lock );

    return EOK;

}

int eth_packet_space_message( device_id_t device_id, size_t * addr_len, size_t * prefix, size_t * content, size_t * suffix ){

    eth_device_ref  device;

    if( !( addr_len && prefix && content && suffix )) return EBADMEM;

    rwlock_read_lock( & eth_globals.devices_lock );

    device = eth_devices_find( & eth_globals.devices, device_id );

    if( ! device ){

        rwlock_read_unlock( & eth_globals.devices_lock );

        return ENOENT;

    }

    * content = device->mtu;

    rwlock_read_unlock( & eth_globals.devices_lock );

    * addr_len = ETH_ADDR;

    * prefix = ETH_PREFIX;

    * suffix = ETH_MIN_CONTENT + ETH_SUFFIX;

    return EOK;

}

int eth_addr_message( device_id_t device_id, eth_addr_type_t type, measured_string_ref * address ){

    eth_device_ref  device;

    if( ! address ) return EBADMEM;

    if( type == ETH_BROADCAST_ADDR ){

        * address = eth_globals.broadcast_addr;

    }else{

        rwlock_read_lock( & eth_globals.devices_lock );

        device = eth_devices_find( & eth_globals.devices, device_id );

        if( ! device ){

            rwlock_read_unlock( & eth_globals.devices_lock );

            return ENOENT;

        }

        * address = device->addr;

        rwlock_read_unlock( & eth_globals.devices_lock );

    }

    return ( * address ) ? EOK : ENOENT;

}

int nil_register_message( services_t service, int phone ){

    eth_proto_ref   proto;

    int             protocol;

    int             index;

    protocol = protocol_map( SERVICE_ETHERNET, service );

    if( ! protocol ) return ENOENT;

    rwlock_write_lock( & eth_globals.protos_lock );

    proto = eth_protos_find( & eth_globals.protos, protocol );

    if( proto ){

        proto->phone = phone;

        rwlock_write_unlock( & eth_globals.protos_lock );

        return EOK;

    }else{

        proto = ( eth_proto_ref ) malloc( sizeof( eth_proto_t ));

        if( ! proto ){

            rwlock_write_unlock( & eth_globals.protos_lock );

            return ENOMEM;

        }

        proto->service = service;

        proto->protocol = protocol;

        proto->phone = phone;

        index = eth_protos_add( & eth_globals.protos, protocol, proto );

        if( index < 0 ){

            rwlock_write_unlock( & eth_globals.protos_lock );

            free( proto );

            return index;

        }

    }

    printf( "New protocol registered:\n\tprotocol\t= 0x%x\n\tservice\t= %d\n\tphone\t= %d\n", proto->protocol, proto->service, proto->phone );

    rwlock_write_unlock( & eth_globals.protos_lock );

    return EOK;

}

int eth_prepare_packet( int flags, packet_t packet, uint8_t * src_addr, int ethertype, size_t mtu ){

    eth_header_ex_ref   header;

    eth_header_ref      header_dix;

    eth_fcs_ref         fcs;

    uint8_t *           src;

    uint8_t *           dest;

    int                 length;

    int                 i;

    void *              padding;

    eth_preamble_ref    preamble;

    length = packet_get_addr( packet, & src, & dest );

    if( length < 0 ) return length;

    if( length != ETH_ADDR ) return EINVAL;

    length = packet_get_data_length( packet );

    if( length > mtu ) return EINVAL;

    if( length < ETH_MIN_TAGGED_CONTENT( flags )){

        padding = packet_suffix( packet, ETH_MIN_TAGGED_CONTENT( flags ) - length );

        if( ! padding ) return ENOMEM;

        bzero( padding, ETH_MIN_TAGGED_CONTENT( flags ) - length );

    }

    if( IS_DUMMY( flags )){

        preamble = PACKET_PREFIX( packet, eth_preamble_t );

        if( ! preamble ) return ENOMEM;

        for( i = 0; i < 7; ++ i ) preamble->preamble[ i ] = ETH_PREAMBLE;

        preamble->sfd = ETH_SFD;

    }

    // TODO LSAP only device

    if( IS_DIX( flags ) || IS_8023_2_LSAP( flags )){

        header_dix = PACKET_PREFIX( packet, eth_header_t );

        if( ! header_dix ) return ENOMEM;

        header_dix->ethertype = ( uint16_t ) ethertype;

        memcpy( header_dix->src, src_addr, ETH_ADDR );

        memcpy( header_dix->dest, dest, ETH_ADDR );

        src = & header_dix->dest[ 0 ];

    }else if( IS_8023_2_SNAP( flags )){

        header = PACKET_PREFIX( packet, eth_header_ex_t );

        if( ! header ) return ENOMEM;

        header->header.ethertype = htons( length + sizeof( eth_header_lsap_t ) + sizeof( eth_header_snap_t ));

        header->lsap.dsap = ( uint16_t ) ETH_LSAP_SNAP;

        header->lsap.ssap = header->lsap.dsap;

        header->lsap.ctrl = 0;

        for( i = 0; i < 3; ++ i ) header->snap.proto[ i ] = 0;

        header->snap.ethertype = ( uint16_t ) ethertype;

        memcpy( header->header.src, src_addr, ETH_ADDR );

        memcpy( header->header.dest, dest, ETH_ADDR );

        src = & header->header.dest[ 0 ];

    }

    if( IS_DUMMY( flags )){

        fcs = PACKET_SUFFIX( packet, eth_fcs_t );

        if( ! fcs ) return ENOMEM;

        * fcs = htonl( ~ compute_crc32( ~ 0, src, ((( void * ) fcs ) - (( void * ) src )) * 8 ));

    }

    return EOK;

}

int eth_send_message( device_id_t device_id, packet_t packet, services_t sender ){

    ERROR_DECLARE;

    eth_device_ref      device;

    packet_t            next;

    packet_t            tmp;

    int                 ethertype;

    ethertype = htons( protocol_map( SERVICE_ETHERNET, sender ));

    if( ! ethertype ){

        pq_release( eth_globals.net_phone, packet_get_id( packet ));

        return EINVAL;

    }

    rwlock_read_lock( & eth_globals.devices_lock );

    device = eth_devices_find( & eth_globals.devices, device_id );

    if( ! device ){

        rwlock_read_unlock( & eth_globals.devices_lock );

        return ENOENT;

    }

    // process packet queue

    next = packet;

    do{

        if( ERROR_OCCURRED( eth_prepare_packet( device->flags, next, ( uint8_t * ) device->addr->value, ethertype, device->mtu ))){

            // release invalid packet

            tmp = pq_detach( next );

            if( next == packet ) packet = tmp;

            pq_release( eth_globals.net_phone, packet_get_id( next ));

            next = tmp;

        }else{

            next = pq_next( next );

        }

    }while( next );

    // send packet queue

    if( packet ){

        netif_send_msg( device->phone, device_id, packet, SERVICE_ETHERNET );

    }

    rwlock_read_unlock( & eth_globals.devices_lock );

    return EOK;

}

int nil_message( ipc_callid_t callid, ipc_call_t * call, ipc_call_t * answer, int * answer_count ){

    ERROR_DECLARE;

    measured_string_ref address;

    packet_t            packet;

//  printf( "message %d - %d\n", IPC_GET_METHOD( * call ), NET_NIL_FIRST );

    * answer_count = 0;

    switch( IPC_GET_METHOD( * call )){

        case IPC_M_PHONE_HUNGUP:

            return EOK;

        case NET_NIL_DEVICE:

            return eth_device_message( IPC_GET_DEVICE( call ), IPC_GET_SERVICE( call ), NIL_GET_MTU( call ));

        case NET_NIL_SEND:

            ERROR_PROPAGATE( packet_translate( eth_globals.net_phone, & packet, IPC_GET_PACKET( call )));

            return eth_send_message( IPC_GET_DEVICE( call ), packet, IPC_GET_SERVICE( call ));

        case NET_NIL_PACKET_SPACE:

            ERROR_PROPAGATE( eth_packet_space_message( IPC_GET_DEVICE( call ), IPC_SET_ADDR( answer ), IPC_SET_PREFIX( answer ), IPC_SET_CONTENT( answer ), IPC_SET_SUFFIX( answer )));

            * answer_count = 4;

            return EOK;

        case NET_NIL_ADDR:

            ERROR_PROPAGATE( eth_addr_message( IPC_GET_DEVICE( call ), ETH_LOCAL_ADDR, & address ));

            return measured_strings_reply( address, 1 );

        case NET_NIL_BROADCAST_ADDR:

            ERROR_PROPAGATE( eth_addr_message( IPC_GET_DEVICE( call ), ETH_BROADCAST_ADDR, & address ));

            return measured_strings_reply( address, 1 );

        case IPC_M_CONNECT_TO_ME:

            return nil_register_message( NIL_GET_PROTO( call ), IPC_GET_PHONE( call ));

    }

    return ENOTSUP;

}

void eth_receiver( ipc_callid_t iid, ipc_call_t * icall ){

    ERROR_DECLARE;

    packet_t        packet;

    while( true ){

//      printf( "message %d - %d\n", IPC_GET_METHOD( * icall ), NET_NIL_FIRST );

        switch( IPC_GET_METHOD( * icall )){

            case NET_NIL_DEVICE_STATE:

                nil_device_state_msg( 0, IPC_GET_DEVICE( icall ), IPC_GET_STATE( icall ));

                ipc_answer_0( iid, EOK );

                break;

            case NET_NIL_RECEIVED:

                if( ! ERROR_OCCURRED( packet_translate( eth_globals.net_phone, & packet, IPC_GET_PACKET( icall )))){

                    ERROR_CODE = nil_received_msg( 0, IPC_GET_DEVICE( icall ), packet, 0 );

                }

                ipc_answer_0( iid, ERROR_CODE );

                break;

            default:

                ipc_answer_0( iid, ENOTSUP );

        }

        iid = async_get_call( icall );

    }

}

/** @}

 */