以太网(ethernet.h)

最新推荐文章于 2025-11-24 09:23:52 发布

原创最新推荐文章于 2025-11-24 09:23:52 发布 · 4.6k 阅读

CC 4.0 BY-SA版权

本文定义了以太网地址和头部结构，列举了常见的以太网协议类型，并提供了以太网包长度验证的方法。

#ifndef __NET_ETHERNET_H
#define __NET_ETHERNET_H 1

#include <sys/cdefs.h>
#include <sys/types.h>
#include <linux/if_ether.h>     /* IEEE 802.3 Ethernet constants */

__BEGIN_DECLS

/* This is a name for the 48 bit ethernet address available on many
   systems. */
struct ether_addr
{
u_int8_t ether_addr_octet[ETH_ALEN];
} __attribute__ ((__packed__));

/* 10Mb/s ethernet header */
struct ether_header//以太网头部
{
u_int8_t ether_dhost[ETH_ALEN];   /* destination eth addr   */
u_int8_t ether_shost[ETH_ALEN];   /* source ether addr   */
u_int16_t ether_type;                /* packet type ID field   */
} __attribute__ ((__packed__));

/* Ethernet protocol ID's */ 以太网协议ID
#define   ETHERTYPE_PUP       0x0200          /* Xerox PUP */
#define ETHERTYPE_SPRITE   0x0500       /* Sprite */
#define   ETHERTYPE_IP       0x0800       /* IP */
#define   ETHERTYPE_ARP       0x0806       /* Address resolution */
#define   ETHERTYPE_REVARP   0x8035       /* Reverse ARP */
#define ETHERTYPE_AT       0x809B       /* AppleTalk protocol */
#define ETHERTYPE_AARP       0x80F3       /* AppleTalk ARP */
#define   ETHERTYPE_VLAN       0x8100       /* IEEE 802.1Q VLAN tagging */
#define ETHERTYPE_IPX       0x8137       /* IPX */
#define   ETHERTYPE_IPV6       0x86dd       /* IP protocol version 6 */
#define ETHERTYPE_LOOPBACK   0x9000       /* used to test interfaces */

#define   ETHER_ADDR_LEN   ETH_ALEN                 /* size of ethernet addr */
#define   ETHER_TYPE_LEN   2                        /* bytes in type field */
#define   ETHER_CRC_LEN   4                        /* bytes in CRC field */
#define   ETHER_HDR_LEN   ETH_HLEN                 /* total octets in header */
#define   ETHER_MIN_LEN   (ETH_ZLEN + ETHER_CRC_LEN) /* min packet length */
#define   ETHER_MAX_LEN   (ETH_FRAME_LEN + ETHER_CRC_LEN) /* max packet length */

/* make sure ethenet length is valid */
#define   ETHER_IS_VALID_LEN(foo)   \
   ((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN)

/*
* The ETHERTYPE_NTRAILER packet types starting at ETHERTYPE_TRAIL have
* (type-ETHERTYPE_TRAIL)*512 bytes of data followed
* by an ETHER type (as given above) and then the (variable-length) header.
*/
#define   ETHERTYPE_TRAIL       0x1000       /* Trailer packet */
#define   ETHERTYPE_NTRAILER   16

#define   ETHERMTU   ETH_DATA_LEN
#define   ETHERMIN   (ETHER_MIN_LEN - ETHER_HDR_LEN - ETHER_CRC_LEN)

__END_DECLS

#endif   /* net/ethernet.h */