FreeBSD/Linux Kernel Cross Reference
sys/mips/atheros/ar71xx_macaddr.c

     /*-
      * Copyright (c) 2015, Adrian Chadd <adrian@FreeBSD.org>
      * 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 unmodified, 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/12.0/sys/mips/atheros/ar71xx_macaddr.c 280798 2015-03-28 23:40:29Z adrian $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/types.h>
    #include <sys/libkern.h>
    
    #include <net/ethernet.h>
    
    #include <mips/atheros/ar71xx_macaddr.h>
    
    /*
     * Some boards don't have a separate MAC address for each individual
     * device on-board, but instead need to derive them from a single MAC
     * address stored somewhere.
     */
    uint8_t ar71xx_board_mac_addr[ETHER_ADDR_LEN];
    
    /*
     * Initialise a MAC address 'dst' from a MAC address 'src'.
     *
     * 'offset' is added to the low three bytes to allow for sequential
     * MAC addresses to be derived from a single one.
     *
     * 'is_local' is whether this 'dst' should be made a local MAC address.
     *
     * Returns 0 if it was successfully initialised, -1 on error.
     */
    int
    ar71xx_mac_addr_init(unsigned char *dst, const unsigned char *src,
        int offset, int is_local)
    {
            int t;
    
            if (dst == NULL || src == NULL)
                    return (-1);
    
            /* XXX TODO: validate 'src' is a valid MAC address */
    
            t = (((uint32_t) src[3]) << 16)
                + (((uint32_t) src[4]) << 8)
                + ((uint32_t) src[5]);
    
            /* Note: this is handles both positive and negative offsets */
            t += offset;
    
            dst[0] = src[0];
            dst[1] = src[1];
            dst[2] = src[2];
            dst[3] = (t >> 16) & 0xff;
            dst[4] = (t >> 8) & 0xff;
            dst[5] = t & 0xff;
    
            if (is_local)
                    dst[0] |= 0x02;
    
            /* Everything's okay */
            return (0);
    }
    
    /*
     * Initialise a random MAC address for use by if_arge.c and whatever
     * else requires it.
     *
     * Returns 0 on success, -1 on error.
     */
    int
    ar71xx_mac_addr_random_init(unsigned char *dst)
    {
            uint32_t rnd;
    
           rnd = arc4random();
   
           dst[0] = 'b';
           dst[1] = 's';
           dst[2] = 'd';
           dst[3] = (rnd >> 24) & 0xff;
           dst[4] = (rnd >> 16) & 0xff;
           dst[5] = (rnd >> 8) & 0xff;
   
           return (0);
   }

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