source: mainline/uspace/srv/net/nil/eth/eth.c@ aadf01e

/*
 * 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[in] flags The ethernet flags.
 *  @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[in] flags The ethernet flags.
 *  @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[in] flags The ethernet flags.
 *  @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[in] iid The message identifier.
 *  @param[in,out] icall The message parameters.
 */
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[in] device_id The new device identifier.
 *  @param[in] service The device driver service.
 *  @param[in] mtu The device maximum transmission unit.
 *  @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[in] service The module service.
 *  @param[in] phone The service phone.
 *  @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[in] device_id The device identifier.
 *  @param[out] addr_len The minimum reserved address length.
 *  @param[out] prefix The minimum reserved prefix size.
 *  @param[out] content The maximum content size.
 *  @param[out] suffix The minimum reserved suffix size.
 *  @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[in] device_id The device identifier.
 *  @param[in] type Type of the desired address.
 *  @param[out] address The device hardware address.
 *  @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[in] device_id The device identifier.
 *  @param[in] packet The packet queue.
 *  @param[in] sender The sending module service.
 *  @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[in] flags The device flags.
 *  @param[in] packet The packet.
 *  @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[in] flags The device flags.
 *  @param[in] packet The packet.
 *  @param[in] src_addr The source hardware address.
 *  @param[in] ethertype The ethernet protocol type.
 *  @param[in] mtu The device maximum transmission unit.
 *  @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] = {{str_dup("ETH_MODE"), 8}, {str_dup("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_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)){
                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;
                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);
        }
}

/** @}
 */