FreeBSD/Linux Kernel Cross Reference
sys/net/if_dl.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1990, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)if_dl.h     8.1 (Berkeley) 6/10/93
     * $FreeBSD$
     */
    
    #ifndef _NET_IF_DL_H_
    #define _NET_IF_DL_H_
    
    /*
     * 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_LINK */
            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[46];   /* minimum work area, can be larger;
                                       contains both if name and ll address */
    };
    
    #define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
    #define CLLADDR(s) ((c_caddr_t)((s)->sdl_data + (s)->sdl_nlen))
    #define LLINDEX(s) ((s)->sdl_index)
    
    
    struct ifnet;
    struct sockaddr_dl *link_alloc_sdl(size_t, int);
    void link_free_sdl(struct sockaddr *sa);
    struct sockaddr_dl *link_init_sdl(struct ifnet *, struct sockaddr *, u_char);
    
    #ifndef _KERNEL
    
    #include <sys/cdefs.h>
    
    __BEGIN_DECLS
    void    link_addr(const char *, struct sockaddr_dl *);
    char    *link_ntoa(const struct sockaddr_dl *);
    __END_DECLS
    
    #endif /* !_KERNEL */
    
    #endif

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