xref: /freebsd/sys/net/if_dl.h (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
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 
32 #ifndef _NET_IF_DL_H_
33 #define _NET_IF_DL_H_
34 
35 /*
36  * A Link-Level Sockaddr may specify the interface in one of two
37  * ways: either by means of a system-provided index number (computed
38  * anew and possibly differently on every reboot), or by a human-readable
39  * string such as "il0" (for managerial convenience).
40  *
41  * Census taking actions, such as something akin to SIOCGCONF would return
42  * both the index and the human name.
43  *
44  * High volume transactions (such as giving a link-level ``from'' address
45  * in a recvfrom or recvmsg call) may be likely only to provide the indexed
46  * form, (which requires fewer copy operations and less space).
47  *
48  * The form and interpretation  of the link-level address is purely a matter
49  * of convention between the device driver and its consumers; however, it is
50  * expected that all drivers for an interface of a given if_type will agree.
51  */
52 
53 /*
54  * Structure of a Link-Level sockaddr:
55  */
56 struct sockaddr_dl {
57 	u_char	sdl_len;	/* Total length of sockaddr */
58 	u_char	sdl_family;	/* AF_LINK */
59 	u_short	sdl_index;	/* if != 0, system given index for interface */
60 	u_char	sdl_type;	/* interface type */
61 	u_char	sdl_nlen;	/* interface name length, no trailing 0 reqd. */
62 	u_char	sdl_alen;	/* link level address length */
63 	u_char	sdl_slen;	/* link layer selector length */
64 	char	sdl_data[46];	/* minimum work area, can be larger;
65 				   contains both if name and ll address */
66 };
67 
68 #define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
69 #define CLLADDR(s) ((c_caddr_t)((s)->sdl_data + (s)->sdl_nlen))
70 #define LLINDEX(s) ((s)->sdl_index)
71 
72 struct ifnet;
73 struct sockaddr_dl *link_alloc_sdl(size_t, int);
74 void link_free_sdl(struct sockaddr *sa);
75 struct sockaddr_dl *link_init_sdl(struct ifnet *, struct sockaddr *, u_char);
76 
77 #ifndef _KERNEL
78 
79 #include <sys/cdefs.h>
80 
81 __BEGIN_DECLS
82 void	link_addr(const char *, struct sockaddr_dl *);
83 char	*link_ntoa(const struct sockaddr_dl *);
84 __END_DECLS
85 
86 #endif /* !_KERNEL */
87 
88 #endif
89