[unix-history] / usr / src / sys / net / if_dl.h

/*
 * Copyright (c) 1990 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)if_dl.h	7.1 (Berkeley) %G%
 */

/* 
 * A Link-Level Sockaddr may specify the interface in one of two
 * ways: either by means of a system-provided index number (computed
 * anew and possibly differently on every reboot), or by a human-readable
 * string such as "il0" (for managerial convenience).
 * 
 * Census taking actions, such as something akin to SIOCGCONF would return
 * both the index and the human name.
 * 
 * High volume transactions (such as giving a link-level ``from'' address
 * in a recvfrom or recvmsg call) may be likely only to provide the indexed
 * form, (which requires fewer copy operations and less space).
 * 
 * The form and interpretation  of the link-level address is purely a matter
 * of convention between the device driver and its consumers; however, it is
 * expected that all drivers for an interface of a given if_type will agree.
 */

/*
 * Structure of a Link-Level sockaddr:
 */
struct sockaddr_dl {
	u_char	sdl_len;	/* Total length of sockaddr */
	u_char	sdl_family;	/* AF_DLI */
	u_short	sdl_index;	/* if != 0, system given index for interface */
	u_char	sdl_type;	/* interface type */
	u_char	sdl_nlen;	/* interface name length, no trailing 0 reqd. */
	u_char	sdl_alen;	/* link level address length */
	u_char	sdl_slen;	/* link layer selector length */
	char	sdl_data[12];	/* minimum work area, can be larger;
				   contains both if name and ll address */
};

#define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
Commit	Line	Data
b7d22786 MK	1	/*
	2	* Copyright (c) 1990 Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*
	7	* @(#)if_dl.h 7.1 (Berkeley) %G%
	8	*/
	9
	10	/*
	11	* A Link-Level Sockaddr may specify the interface in one of two
	12	* ways: either by means of a system-provided index number (computed
	13	* anew and possibly differently on every reboot), or by a human-readable
	14	* string such as "il0" (for managerial convenience).
	15	*
	16	* Census taking actions, such as something akin to SIOCGCONF would return
	17	* both the index and the human name.
	18	*
	19	* High volume transactions (such as giving a link-level ``from'' address
	20	* in a recvfrom or recvmsg call) may be likely only to provide the indexed
	21	* form, (which requires fewer copy operations and less space).
	22	*
	23	* The form and interpretation of the link-level address is purely a matter
	24	* of convention between the device driver and its consumers; however, it is
	25	* expected that all drivers for an interface of a given if_type will agree.
	26	*/
	27
	28	/*
	29	* Structure of a Link-Level sockaddr:
	30	*/
	31	struct sockaddr_dl {
	32	u_char sdl_len; /* Total length of sockaddr */
	33	u_char sdl_family; /* AF_DLI */
	34	u_short sdl_index; /* if != 0, system given index for interface */
	35	u_char sdl_type; /* interface type */
	36	u_char sdl_nlen; /* interface name length, no trailing 0 reqd. */
	37	u_char sdl_alen; /* link level address length */
	38	u_char sdl_slen; /* link layer selector length */
	39	char sdl_data[12]; /* minimum work area, can be larger;
	40	contains both if name and ll address */
	41	};
	42
	43	#define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
	44