xref: /freebsd/sys/net/if_dl.h (revision ad30f8e79bd1007cc2476e491bd21b4f5e389e0a)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)if_dl.h	8.1 (Berkeley) 6/10/93
30  * $FreeBSD$
31  */
32 
33 #ifndef _NET_IF_DL_H_
34 #define _NET_IF_DL_H_
35 
36 /*
37  * A Link-Level Sockaddr may specify the interface in one of two
38  * ways: either by means of a system-provided index number (computed
39  * anew and possibly differently on every reboot), or by a human-readable
40  * string such as "il0" (for managerial convenience).
41  *
42  * Census taking actions, such as something akin to SIOCGCONF would return
43  * both the index and the human name.
44  *
45  * High volume transactions (such as giving a link-level ``from'' address
46  * in a recvfrom or recvmsg call) may be likely only to provide the indexed
47  * form, (which requires fewer copy operations and less space).
48  *
49  * The form and interpretation  of the link-level address is purely a matter
50  * of convention between the device driver and its consumers; however, it is
51  * expected that all drivers for an interface of a given if_type will agree.
52  */
53 
54 /*
55  * Structure of a Link-Level sockaddr:
56  */
57 struct sockaddr_dl {
58 	u_char	sdl_len;	/* Total length of sockaddr */
59 	u_char	sdl_family;	/* AF_LINK */
60 	u_short	sdl_index;	/* if != 0, system given index for interface */
61 	u_char	sdl_type;	/* interface type */
62 	u_char	sdl_nlen;	/* interface name length, no trailing 0 reqd. */
63 	u_char	sdl_alen;	/* link level address length */
64 	u_char	sdl_slen;	/* link layer selector length */
65 	char	sdl_data[46];	/* minimum work area, can be larger;
66 				   contains both if name and ll address */
67 };
68 
69 #define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
70 
71 #ifndef _KERNEL
72 
73 #include <sys/cdefs.h>
74 
75 __BEGIN_DECLS
76 void	link_addr(const char *, struct sockaddr_dl *);
77 char	*link_ntoa(const struct sockaddr_dl *);
78 __END_DECLS
79 
80 #endif /* !_KERNEL */
81 
82 #endif
83