ethernet.h

James Antognini和Tom Divine提供的PASSTHRU的编成实例。

/*
 * Fundamental constants relating to ethernet.
 *
 * $FreeBSD: src/sys/net/ethernet.h,v 1.22 2002/11/14 23:28:47 sam Exp $
 *
 */

#ifndef _NET_ETHERNET_H_
#define _NET_ETHERNET_H_

/*
 * Somce basic Ethernet constants.
 */
#define	ETHER_ADDR_LEN		6	/* length of an Ethernet address */
#define	ETHER_TYPE_LEN		2	/* length of the Ethernet type field */
#define	ETHER_CRC_LEN		4	/* length of the Ethernet CRC */
#define	ETHER_HDR_LEN		(ETHER_ADDR_LEN*2+ETHER_TYPE_LEN)
#define	ETHER_MIN_LEN		64	/* minimum frame len, including CRC */
#define	ETHER_MAX_LEN		1518	/* maximum frame len, including CRC */
#define	ETHER_MAX_LEN_JUMBO	9018	/* max jumbo frame len, including CRC */

#define	ETHER_VLAN_ENCAP_LEN	4	/* len of 802.1Q VLAN encapsulation */
/*
 * Mbuf adjust factor to force 32-bit alignment of IP header.
 * Drivers should do m_adj(m, ETHER_ALIGN) when setting up a
 * receive so the upper layers get the IP header properly aligned
 * past the 14-byte Ethernet header.
 */
#define	ETHER_ALIGN		2	/* driver adjust for IP hdr alignment */

/*
 * Compute the maximum frame size based on ethertype (i.e. possible
 * encapsulation) and whether or not an FCS is present.
 */
#define	ETHER_MAX_FRAME(ifp, etype, hasfcs)				\
	((ifp)->if_mtu + ETHER_HDR_LEN +				\
	 ((hasfcs) ? ETHER_CRC_LEN : 0) +				\
	 (((etype) == ETHERTYPE_VLAN) ? ETHER_VLAN_ENCAP_LEN : 0))

/*
 * Ethernet-specific mbuf flags.
 */
#define	M_HASFCS	M_PROTO5	/* FCS included at end of frame */

/*
 * Ethernet CRC32 polynomials (big- and little-endian verions).
 */
#define	ETHER_CRC_POLY_LE	0xedb88320
#define	ETHER_CRC_POLY_BE	0x04c11db6

/*
 * A macro to validate a length with
 */
#define	ETHER_IS_VALID_LEN(foo)	\
	((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN)

/*
 * Structure of a 10Mb/s Ethernet header.
 */
struct	ether_header {
	UCHAR	ether_dhost[ETHER_ADDR_LEN];
	UCHAR	ether_shost[ETHER_ADDR_LEN];
	USHORT	ether_type;
};

/*
 * Structure of a 48-bit Ethernet address.
 */
struct	ether_addr {
	UCHAR octet[ETHER_ADDR_LEN];
};

#define	ETHER_IS_MULTICAST(addr) (*(addr) & 0x01) /* is address mcast/bcast? */

/*
 *  NOTE: 0x0000-0x05DC (0..1500) are generally IEEE 802.3 length fields.
 *  However, there are some conflicts.
 */

#define	ETHERTYPE_8023		0x0004	/* IEEE 802.3 packet */
		   /* 0x0101 .. 0x1FF	   Experimental */
#define	ETHERTYPE_PUP		0x0200	/* Xerox PUP protocol - see 0A00 */
#define	ETHERTYPE_PUPAT		0x0200	/* PUP Address Translation - see 0A01 */
#define	ETHERTYPE_SPRITE	0x0500	/* ??? */
			     /* 0x0400	   Nixdorf */
#define	ETHERTYPE_NS		0x0600	/* XNS */
#define	ETHERTYPE_NSAT		0x0601	/* XNS Address Translation (3Mb only) */
#define	ETHERTYPE_DLOG1 	0x0660	/* DLOG (?) */
#define	ETHERTYPE_DLOG2 	0x0661	/* DLOG (?) */
#define	ETHERTYPE_IP		0x0800	/* IP protocol */
#define	ETHERTYPE_X75		0x0801	/* X.75 Internet */
#define	ETHERTYPE_NBS		0x0802	/* NBS Internet */
#define	ETHERTYPE_ECMA		0x0803	/* ECMA Internet */
#define	ETHERTYPE_CHAOS 	0x0804	/* CHAOSnet */
#define	ETHERTYPE_X25		0x0805	/* X.25 Level 3 */
#define	ETHERTYPE_ARP		0x0806	/* Address resolution protocol */
#define	ETHERTYPE_NSCOMPAT	0x0807	/* XNS Compatibility */
#define	ETHERTYPE_FRARP 	0x0808	/* Frame Relay ARP (RFC1701) */
			     /* 0x081C	   Symbolics Private */
		    /* 0x0888 - 0x088A	   Xyplex */
#define	ETHERTYPE_UBDEBUG	0x0900	/* Ungermann-Bass network debugger */
#define	ETHERTYPE_IEEEPUP	0x0A00	/* Xerox IEEE802.3 PUP */
#define	ETHERTYPE_IEEEPUPAT	0x0A01	/* Xerox IEEE802.3 PUP Address Translation */
#define	ETHERTYPE_VINES 	0x0BAD	/* Banyan VINES */
#define	ETHERTYPE_VINESLOOP	0x0BAE	/* Banyan VINES Loopback */
#define	ETHERTYPE_VINESECHO	0x0BAF	/* Banyan VINES Echo */

/*		       0x1000 - 0x100F	   Berkeley Trailer */
/*
 * 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	ETHERTYPE_DCA		0x1234	/* DCA - Multicast */
#define	ETHERTYPE_VALID 	0x1600	/* VALID system protocol */
#define	ETHERTYPE_DOGFIGHT	0x1989	/* Artificial Horizons ("Aviator" dogfight simulator [on Sun]) */
#define	ETHERTYPE_RCL		0x1995	/* Datapoint Corporation (RCL lan protocol) */

					/* The following 3C0x types
					   are unregistered: */
#define	ETHERTYPE_NBPVCD	0x3C00	/* 3Com NBP virtual circuit datagram (like XNS SPP) not registered */
#define	ETHERTYPE_NBPSCD	0x3C01	/* 3Com NBP System control datagram not registered */
#define	ETHERTYPE_NBPCREQ	0x3C02	/* 3Com NBP Connect request (virtual cct) not registered */
#define	ETHERTYPE_NBPCRSP	0x3C03	/* 3Com NBP Connect repsonse not registered */
#define	ETHERTYPE_NBPCC		0x3C04	/* 3Com NBP Connect complete not registered */
#define	ETHERTYPE_NBPCLREQ	0x3C05	/* 3Com NBP Close request (virtual cct) not registered */
#define	ETHERTYPE_NBPCLRSP	0x3C06	/* 3Com NBP Close response not registered */
#define	ETHERTYPE_NBPDG		0x3C07	/* 3Com NBP Datagram (like XNS IDP) not registered */
#define	ETHERTYPE_NBPDGB	0x3C08	/* 3Com NBP Datagram broadcast not registered */
#define	ETHERTYPE_NBPCLAIM	0x3C09	/* 3Com NBP Claim NetBIOS name not registered */
#define	ETHERTYPE_NBPDLTE	0x3C0A	/* 3Com NBP Delete Netbios name not registered */
#define	ETHERTYPE_NBPRAS	0x3C0B	/* 3Com NBP Remote adaptor status request not registered */
#define	ETHERTYPE_NBPRAR	0x3C0C	/* 3Com NBP Remote adaptor response not registered */
#define	ETHERTYPE_NBPRST	0x3C0D	/* 3Com NBP Reset not registered */

#define	ETHERTYPE_PCS		0x4242	/* PCS Basic Block Protocol */
#define	ETHERTYPE_IMLBLDIAG	0x424C	/* Information Modes Little Big LAN diagnostic */
#define	ETHERTYPE_DIDDLE	0x4321	/* THD - Diddle */
#define	ETHERTYPE_IMLBL		0x4C42	/* Information Modes Little Big LAN */
#define	ETHERTYPE_SIMNET	0x5208	/* BBN Simnet Private */
#define	ETHERTYPE_DECEXPER	0x6000	/* DEC Unassigned, experimental */
#define	ETHERTYPE_MOPDL		0x6001	/* DEC MOP dump/load */
#define	ETHERTYPE_MOPRC		0x6002	/* DEC MOP remote console */
#define	ETHERTYPE_DECnet	0x6003	/* DEC DECNET Phase IV route */
#define	ETHERTYPE_DN		ETHERTYPE_DECnet	/* libpcap, tcpdump */
#define	ETHERTYPE_LAT		0x6004	/* DEC LAT */
#define	ETHERTYPE_DECDIAG	0x6005	/* DEC diagnostic protocol (at interface initialization?) */
#define	ETHERTYPE_DECCUST	0x6006	/* DEC customer protocol */
#define	ETHERTYPE_SCA		0x6007	/* DEC LAVC, SCA */
#define	ETHERTYPE_AMBER		0x6008	/* DEC AMBER */
#define	ETHERTYPE_DECMUMPS	0x6009	/* DEC MUMPS */
		    /* 0x6010 - 0x6014	   3Com Corporation */
#define	ETHERTYPE_TRANSETHER	0x6558	/* Trans Ether Bridging (RFC1701)*/
#define	ETHERTYPE_RAWFR		0x6559	/* Raw Frame Relay (RFC1701) */
#define	ETHERTYPE_UBDL		0x7000	/* Ungermann-Bass download */
#define	ETHERTYPE_UBNIU		0x7001	/* Ungermann-Bass NIUs */
#define	ETHERTYPE_UBDIAGLOOP	0x7002	/* Ungermann-Bass diagnostic/loopback */
#define	ETHERTYPE_UBNMC		0x7003	/* Ungermann-Bass ??? (NMC to/from UB Bridge) */
#define	ETHERTYPE_UBBST		0x7005	/* Ungermann-Bass Bridge Spanning Tree */
#define	ETHERTYPE_OS9		0x7007	/* OS/9 Microware */
#define	ETHERTYPE_OS9NET	0x7009	/* OS/9 Net? */
		    /* 0x7020 - 0x7029	   LRT (England) (now Sintrom) */
#define	ETHERTYPE_RACAL		0x7030	/* Racal-Interlan */
#define	ETHERTYPE_PRIMENTS	0x7031	/* Prime NTS (Network Terminal Service) */
#define	ETHERTYPE_CABLETRON	0x7034	/* Cabletron */
#define	ETHERTYPE_CRONUSVLN	0x8003	/* Cronus VLN */
#define	ETHERTYPE_CRONUS	0x8004	/* Cronus Direct */
#define	ETHERTYPE_HP		0x8005	/* HP Probe */
#define	ETHERTYPE_NESTAR	0x8006	/* Nestar */
#define	ETHERTYPE_ATTSTANFORD	0x8008	/* AT&T/Stanford (local use) */
#define	ETHERTYPE_EXCELAN	0x8010	/* Excelan */