1  /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Based on the FreeBSD version of this file. Curiously, that file
      19     lacks a copyright in the header. */
      20  
      21  #ifndef __NET_ETHERNET_H
      22  #define __NET_ETHERNET_H 1
      23  
      24  #include <sys/cdefs.h>
      25  #include <sys/types.h>
      26  #include <stdint.h>
      27  #include <net/if_ether.h>     /* IEEE 802.3 Ethernet constants */
      28  
      29  __BEGIN_DECLS
      30  
      31  /* This is a name for the 48 bit ethernet address available on many
      32     systems.  */
      33  struct ether_addr
      34  {
      35    uint8_t ether_addr_octet[ETH_ALEN];
      36  };
      37  
      38  /* 10Mb/s ethernet header */
      39  struct ether_header
      40  {
      41    uint8_t  ether_dhost[ETH_ALEN];	/* destination eth addr	*/
      42    uint8_t  ether_shost[ETH_ALEN];	/* source ether addr	*/
      43    uint16_t ether_type;		        /* packet type ID field	*/
      44  };
      45  
      46  /* Ethernet protocol ID's */
      47  #define	ETHERTYPE_PUP		0x0200          /* Xerox PUP */
      48  #define	ETHERTYPE_IP		0x0800		/* IP */
      49  #define	ETHERTYPE_ARP		0x0806		/* Address resolution */
      50  #define	ETHERTYPE_REVARP	0x8035		/* Reverse ARP */
      51  
      52  #define	ETHER_ADDR_LEN	ETH_ALEN                 /* size of ethernet addr */
      53  #define	ETHER_TYPE_LEN	2                        /* bytes in type field */
      54  #define	ETHER_CRC_LEN	4                        /* bytes in CRC field */
      55  #define	ETHER_HDR_LEN	ETH_HLEN                 /* total octets in header */
      56  #define	ETHER_MIN_LEN	(ETH_ZLEN + ETH_CRC_LEN) /* min packet length */
      57  #define	ETHER_MAX_LEN	(ETH_FRAME_LEN + ETH_CRC_LEN) /* max packet length */
      58  
      59  /* make sure ethernet length is valid */
      60  #define	ETHER_IS_VALID_LEN(foo)	\
      61  	((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN)
      62  
      63  /*
      64   * The ETHERTYPE_NTRAILER packet types starting at ETHERTYPE_TRAIL have
      65   * (type-ETHERTYPE_TRAIL)*512 bytes of data followed
      66   * by an ETHER type (as given above) and then the (variable-length) header.
      67   */
      68  #define	ETHERTYPE_TRAIL		0x1000		/* Trailer packet */
      69  #define	ETHERTYPE_NTRAILER	16
      70  
      71  #define	ETHERMTU	ETH_DATA_LEN
      72  #define	ETHERMIN	(ETHER_MIN_LEN-ETHER_HDR_LEN-ETHER_CRC_LEN)
      73  
      74  __END_DECLS
      75  
      76  #endif /* net/ethernet.h */