xref: /freebsd/sys/net/if_dl.h (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)if_dl.h	8.1 (Berkeley) 6/10/93
32  * $FreeBSD$
33  */
34 
35 #ifndef _NET_IF_DL_H_
36 #define _NET_IF_DL_H_
37 
38 /*
39  * A Link-Level Sockaddr may specify the interface in one of two
40  * ways: either by means of a system-provided index number (computed
41  * anew and possibly differently on every reboot), or by a human-readable
42  * string such as "il0" (for managerial convenience).
43  *
44  * Census taking actions, such as something akin to SIOCGCONF would return
45  * both the index and the human name.
46  *
47  * High volume transactions (such as giving a link-level ``from'' address
48  * in a recvfrom or recvmsg call) may be likely only to provide the indexed
49  * form, (which requires fewer copy operations and less space).
50  *
51  * The form and interpretation  of the link-level address is purely a matter
52  * of convention between the device driver and its consumers; however, it is
53  * expected that all drivers for an interface of a given if_type will agree.
54  */
55 
56 /*
57  * Structure of a Link-Level sockaddr:
58  */
59 struct sockaddr_dl {
60 	u_char	sdl_len;	/* Total length of sockaddr */
61 	u_char	sdl_family;	/* AF_LINK */
62 	u_short	sdl_index;	/* if != 0, system given index for interface */
63 	u_char	sdl_type;	/* interface type */
64 	u_char	sdl_nlen;	/* interface name length, no trailing 0 reqd. */
65 	u_char	sdl_alen;	/* link level address length */
66 	u_char	sdl_slen;	/* link layer selector length */
67 	char	sdl_data[46];	/* minimum work area, can be larger;
68 				   contains both if name and ll address */
69 };
70 
71 #define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
72 #define CLLADDR(s) ((c_caddr_t)((s)->sdl_data + (s)->sdl_nlen))
73 #define LLINDEX(s) ((s)->sdl_index)
74 
75 
76 struct ifnet;
77 struct sockaddr_dl *link_alloc_sdl(size_t, int);
78 void link_free_sdl(struct sockaddr *sa);
79 struct sockaddr_dl *link_init_sdl(struct ifnet *, struct sockaddr *, u_char);
80 
81 #ifndef _KERNEL
82 
83 #include <sys/cdefs.h>
84 
85 __BEGIN_DECLS
86 void	link_addr(const char *, struct sockaddr_dl *);
87 char	*link_ntoa(const struct sockaddr_dl *);
88 __END_DECLS
89 
90 #endif /* !_KERNEL */
91 
92 #endif
93