* Copyright (c) 1990 Regents of the University of California.
* %sccs.include.redist.c%
* @(#)if_dl.h 7.2 (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:
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))
void link_addr
__P((const char *, struct sockaddr_dl
*));
char *link_ntoa
__P((const struct sockaddr_dl
*));