/* * Copyright (c) 1990 Regents of the University of California. * All rights reserved. * * Redistribution is only permitted until one year after the first shipment * of 4.4BSD by the Regents. Otherwise, redistribution and use in source and * binary forms are permitted provided that: (1) source distributions retain * this entire copyright notice and comment, and (2) distributions including * binaries display the following acknowledgement: This product includes * software developed by the University of California, Berkeley and its * contributors'' in the documentation or other materials provided with the * distribution and in all advertising materials mentioning features or use * of this software. Neither the name of the University nor the names of * its contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * @(#)if_dl.h 7.1 (Berkeley) 7/1/90 */ /* * 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))