source: mainline/uspace/srv/net/nil/eth/eth_header.h@ 774e6d1a

/*
 * 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 protocol header definitions.
 * Based on the IEEE 802.3-2005
 */

#ifndef NET_ETH_HEADER_H_
#define NET_ETH_HEADER_H_

#include <sys/types.h>

/** Ethernet address length. */
#define ETH_ADDR  6

/** Ethernet header preamble value. */
#define ETH_PREAMBLE  0x55

/** Ethernet header start of frame value. */
#define ETH_SFD  0xD5

/** IEEE 802.2 unordered information control field. */
#define IEEE_8023_2_UI  0x03

/** Type definition of the Ethernet header IEEE 802.3 + 802.2 + SNAP extensions.
 * @see eth_header_snap
 */
typedef struct eth_header_snap eth_header_snap_t;

/** Type definition of the Ethernet header IEEE 802.3 + 802.2 + SNAP extensions.
 * @see eth_header_lsap
 */
typedef struct eth_header_lsap eth_header_lsap_t;

/** Type definition of the Ethernet header LSAP extension.
 * @see eth_ieee_lsap
 */
typedef struct eth_ieee_lsap eth_ieee_lsap_t;

/** Type definition of the Ethernet header SNAP extension.
 * @see eth_snap
 */
typedef struct eth_snap eth_snap_t;

/** Type definition of the Ethernet header preamble.
 * @see preamble
 */
typedef struct eth_preamble eth_preamble_t;

/** Type definition of the Ethernet header.
 * @see eth_header
 */
typedef struct eth_header eth_header_t;

/** Ethernet header Link Service Access Point extension. */
struct eth_ieee_lsap {
        /**
         * Destination Service Access Point identifier.
         * The possible values are assigned by an IEEE committee.
         */
        uint8_t dsap;
        
        /**
         * Source Service Access Point identifier.
         * The possible values are assigned by an IEEE committee.
         */
        uint8_t ssap;
        
        /**
         * Control parameter.
         * The possible values are assigned by an IEEE committee.
         */
        uint8_t ctrl;
} __attribute__ ((packed));

/** Ethernet header SNAP extension. */
struct eth_snap {
        /** Protocol identifier or organization code. */
        uint8_t protocol[3];
        
        /**
         * Ethernet protocol identifier in the network byte order (big endian).
         * @see ethernet_protocols.h
         */
        uint16_t ethertype;
} __attribute__ ((packed));

/** Ethernet header preamble.
 *
 * Used for dummy devices.
 */
struct eth_preamble {
        /**
         * Controlling preamble used for the frame transmission synchronization.
         * All should be set to ETH_PREAMBLE.
         */
        uint8_t preamble[7];
        
        /**
         * Start of Frame Delimiter used for the frame transmission
         * synchronization.
         * Should be set to ETH_SFD.
         */
        uint8_t sfd;
} __attribute__ ((packed));

/** Ethernet header. */
struct eth_header {
        /** Destination host Ethernet address (MAC address). */
        uint8_t destination_address[ETH_ADDR];
        /** Source host Ethernet address (MAC address). */
        uint8_t source_address[ETH_ADDR];
        
        /**
         * Ethernet protocol identifier in the network byte order (big endian).
         * @see ethernet_protocols.h
         */
        uint16_t ethertype;
} __attribute__ ((packed));

/** Ethernet header IEEE 802.3 + 802.2 extension. */
struct eth_header_lsap {
        /** Ethernet header. */
        eth_header_t header;
        
        /**
         * LSAP extension.
         * If DSAP and SSAP are set to ETH_LSAP_SNAP the SNAP extension is being
         * used.
         * If DSAP and SSAP fields are equal to ETH_RAW the raw Ethernet packet
         * without any extensions is being used and the frame content starts
         * rigth after the two fields.
         */
        eth_ieee_lsap_t lsap;
} __attribute__ ((packed));

/** Ethernet header IEEE 802.3 + 802.2 + SNAP extensions. */
struct eth_header_snap {
        /** Ethernet header. */
        eth_header_t header;
        
        /**
         * LSAP extension.
         * If DSAP and SSAP are set to ETH_LSAP_SNAP the SNAP extension is being
         * used.
         * If DSAP and SSAP fields are equal to ETH_RAW the raw Ethernet packet
         * without any extensions is being used and the frame content starts
         * rigth after the two fields.
         */
        eth_ieee_lsap_t lsap;
        
        /** SNAP extension. */
        eth_snap_t snap;
} __attribute__ ((packed));

/** Ethernet Frame Check Sequence. */
typedef uint32_t eth_fcs_t;

#endif

/** @}
 */