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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 <string.h>

#include <ipc/ipc.h>
#include <ipc/services.h>

#include "../../err.h"
#include "../../messages.h"
#include "../../modules.h"

#include "../../include/byteorder.h"
#include "../../include/checksum.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 1500u

/** Minimum packet content length.
 */
#define ETH_MIN_CONTENT 46u

/** 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;

/** @name Message processing functions
 */
/*@{*/

/** 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_req() 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 eth_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;

    fibril_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 );
    }
    fibril_rwlock_read_unlock( & eth_globals.protos_lock );
    return EOK;
}

int nil_initialize( int net_phone ){
    ERROR_DECLARE;

    fibril_rwlock_initialize( & eth_globals.devices_lock );
    fibril_rwlock_initialize( & eth_globals.protos_lock );
    fibril_rwlock_write_lock( & eth_globals.devices_lock );
    fibril_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;
    }
    fibril_rwlock_write_unlock( & eth_globals.protos_lock );
    fibril_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;
    eth_proto_ref       proto;

    fibril_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 );
            fibril_rwlock_write_unlock( & eth_globals.devices_lock );
            return EEXIST;
        }else{
            // update mtu
            if(( mtu > 0 ) && ( mtu <= ETH_MAX_TAGGED_CONTENT( device->flags ))){
                device->mtu = mtu;
            }else{
                 device->mtu = ETH_MAX_TAGGED_CONTENT( device->flags );
            }
            printf( "Device %d already exists:\tMTU\t= %d\n", device->device_id, device->mtu );
            fibril_rwlock_write_unlock( & eth_globals.devices_lock );
            // notify all upper layer modules
            fibril_rwlock_read_lock( & eth_globals.protos_lock );
            for( index = 0; index < eth_protos_count( & eth_globals.protos ); ++ index ){
                proto = eth_protos_get_index( & eth_globals.protos, index );
                if ( proto->phone ){
                    il_mtu_changed_msg( proto->phone, device->device_id, device->mtu, proto->service );
                }
            }
            fibril_rwlock_read_unlock( & eth_globals.protos_lock );
            return EOK;
        }
    }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;
        if(( mtu > 0 ) && ( mtu <= ETH_MAX_TAGGED_CONTENT( device->flags ))){
            device->mtu = mtu;
        }else{
             device->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 ))){
            fibril_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 )){
                device->flags |= ETH_8023_2_LSAP;
            }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 ){
            fibril_rwlock_write_unlock( & eth_globals.devices_lock );
            free( device );
            return device->phone;
        }
        // get hardware address
        if( ERROR_OCCURRED( netif_get_addr_req( device->phone, device->device_id, & device->addr, & device->addr_data ))){
            fibril_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 ){
            fibril_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 );
    }
    fibril_rwlock_write_unlock( & eth_globals.devices_lock );
    return EOK;
}

eth_proto_ref eth_process_packet( int flags, packet_t packet ){
    ERROR_DECLARE;

    eth_header_snap_ref header;
    size_t              length;
    eth_type_t          type;
    size_t              prefix;
    size_t              suffix;
    eth_fcs_ref         fcs;
    uint8_t *           data;

    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;
    data = packet_get_data( packet );
    header = ( eth_header_snap_ref ) data;
    type = ntohs( header->header.ethertype );
    if( type >= ETH_MIN_PROTO ){
        // DIX Ethernet
        prefix = sizeof( eth_header_t );
        suffix = 0;
        fcs = ( eth_fcs_ref ) data + length - sizeof( eth_fcs_t );
        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 : 0u;
        fcs = ( eth_fcs_ref ) data + prefix + type + suffix;
        suffix += length - prefix - type;
        length = prefix + type + suffix;
    }else{
        // invalid length/type, should not occurr
        return NULL;
    }
    if( IS_DUMMY( flags )){
        if(( ~ compute_crc32( ~ 0u, data, length * 8 )) != ntohl( * fcs )){
            return NULL;
        }
        suffix += sizeof( eth_fcs_t );
    }
    if( ERROR_OCCURRED( packet_set_addr( packet, header->header.source_address, header->header.destination_address, 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;

    fibril_rwlock_read_lock( & eth_globals.devices_lock );
    device = eth_devices_find( & eth_globals.devices, device_id );
    if( ! device ){
        fibril_rwlock_read_unlock( & eth_globals.devices_lock );
        return ENOENT;
    }
    flags = device->flags;
    fibril_rwlock_read_unlock( & eth_globals.devices_lock );
    fibril_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 );
    fibril_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;
    fibril_rwlock_read_lock( & eth_globals.devices_lock );
    device = eth_devices_find( & eth_globals.devices, device_id );
    if( ! device ){
        fibril_rwlock_read_unlock( & eth_globals.devices_lock );
        return ENOENT;
    }
    * content = device->mtu;
    fibril_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{
        fibril_rwlock_read_lock( & eth_globals.devices_lock );
        device = eth_devices_find( & eth_globals.devices, device_id );
        if( ! device ){
            fibril_rwlock_read_unlock( & eth_globals.devices_lock );
            return ENOENT;
        }
        * address = device->addr;
        fibril_rwlock_read_unlock( & eth_globals.devices_lock );
    }
    return ( * address ) ? EOK : ENOENT;
}

int eth_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;
    fibril_rwlock_write_lock( & eth_globals.protos_lock );
    proto = eth_protos_find( & eth_globals.protos, protocol );
    if( proto ){
        proto->phone = phone;
        fibril_rwlock_write_unlock( & eth_globals.protos_lock );
        return EOK;
    }else{
        proto = ( eth_proto_ref ) malloc( sizeof( eth_proto_t ));
        if( ! proto ){
            fibril_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 ){
            fibril_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 );
    fibril_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_snap_ref header;
    eth_header_lsap_ref header_lsap;
    eth_header_ref      header_dix;
    eth_fcs_ref         fcs;
    uint8_t *           src;
    uint8_t *           dest;
    size_t              length;
    int                 i;
    void *              padding;
    eth_preamble_ref    preamble;

    i = packet_get_addr( packet, & src, & dest );
    if( i < 0 ) return i;
    if( i != 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;
    }
    if( IS_DIX( flags )){
        header_dix = PACKET_PREFIX( packet, eth_header_t );
        if( ! header_dix ) return ENOMEM;
        header_dix->ethertype = ( uint16_t ) ethertype;
        memcpy( header_dix->source_address, src_addr, ETH_ADDR );
        memcpy( header_dix->destination_address, dest, ETH_ADDR );
        src = & header_dix->destination_address[ 0 ];
    }else if( IS_8023_2_LSAP( flags )){
        header_lsap = PACKET_PREFIX( packet, eth_header_lsap_t );
        if( ! header_lsap ) return ENOMEM;
        header_lsap->header.ethertype = htons( length + sizeof( eth_header_lsap_t ));
        header_lsap->lsap.dsap = lsap_unmap( ntohs( ethertype ));
        header_lsap->lsap.ssap = header_lsap->lsap.dsap;
        header_lsap->lsap.ctrl = IEEE_8023_2_UI;
        memcpy( header_lsap->header.source_address, src_addr, ETH_ADDR );
        memcpy( header_lsap->header.destination_address, dest, ETH_ADDR );
        src = & header_lsap->header.destination_address[ 0 ];
    }else if( IS_8023_2_SNAP( flags )){
        header = PACKET_PREFIX( packet, eth_header_snap_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 = IEEE_8023_2_UI;
        for( i = 0; i < 3; ++ i ) header->snap.protocol[ i ] = 0;
        header->snap.ethertype = ( uint16_t ) ethertype;
        memcpy( header->header.source_address, src_addr, ETH_ADDR );
        memcpy( header->header.destination_address, dest, ETH_ADDR );
        src = & header->header.destination_address[ 0 ];
    }
    if( IS_DUMMY( flags )){
        fcs = PACKET_SUFFIX( packet, eth_fcs_t );
        if( ! fcs ) return ENOMEM;
        * fcs = htonl( ~ compute_crc32( ~ 0u, src, length * 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;
    }
    fibril_rwlock_read_lock( & eth_globals.devices_lock );
    device = eth_devices_find( & eth_globals.devices, device_id );
    if( ! device ){
        fibril_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 );
    }
    fibril_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 ), IPC_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 eth_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, ( ipcarg_t ) ERROR_CODE );
                break;
            default:
                ipc_answer_0( iid, ( ipcarg_t ) ENOTSUP );
        }
        iid = async_get_call( icall );
    }
}

/** @}
 */