/*-
 * Copyright (c) 1982, 1989, 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.
 * 4. 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_ethersubr.c      8.1 (Berkeley) 6/10/93
 * $FreeBSD: src/sys/net/if_ethersubr.c,v 1.193.2.12 2006/08/28 02:54:14 thompsa Exp $
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/mbuf.h>
#include <net/ethernet.h>
#include <net/if_vlan_var.h>
#include <netinet/in.h>

#if 0
/*
 * This is for reference.  We have a table-driven version
 * of the little-endian crc32 generator, which is faster
 * than the double-loop.
 */
uint32_t
ether_crc32_le(const uint8_t *buf, size_t len)
{
        size_t i;
        uint32_t crc;
        int bit;
        uint8_t data;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1)
                        carry = (crc ^ data) & 1;
                        crc >>= 1;
                        if (carry)
                                crc = (crc ^ ETHER_CRC_POLY_LE);
        }

        return (crc);
}
#else
uint32_t
ether_crc32_le(const uint8_t *buf, size_t len)
{
        static const uint32_t crctab[] = {
                0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
                0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
                0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
                0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
        };
        size_t i;
        uint32_t crc;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                crc ^= buf[i];
                crc = (crc >> 4) ^ crctab[crc & 0xf];
                crc = (crc >> 4) ^ crctab[crc & 0xf];
        }

        return (crc);
}
#endif

uint32_t
ether_crc32_be(const uint8_t *buf, size_t len)
{
        size_t i;
        uint32_t crc, carry;
        int bit;
        uint8_t data;

        crc = 0xffffffff;       /* initial value */

        for (i = 0; i < len; i++) {
                for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
                        carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
                        crc <<= 1;
                        if (carry)
                                crc = (crc ^ ETHER_CRC_POLY_BE) | carry;
                }
        }

        return (crc);
}

char *
ether_sprintf(const u_char *ap)
{
        static char etherbuf[18];
        snprintf(etherbuf, sizeof (etherbuf),
                "%02x:%02x:%02x:%02x:%02x:%02x",
                (unsigned)ap[0], (unsigned)ap[1], (unsigned)ap[2],
                (unsigned)ap[3], (unsigned)ap[4], (unsigned)ap[5]);
        return (etherbuf);
}

struct mbuf *
ether_vlanencap(struct mbuf *m, uint16_t tag)
{
        struct ether_vlan_header *evl;

        M_PREPEND(m, ETHER_VLAN_ENCAP_LEN, M_NOWAIT);
        if (m == NULL)
                return (NULL);
        /* M_PREPEND takes care of m_len, m_pkthdr.len for us */

        if (m->m_len < sizeof(*evl)) {
                m = m_pullup(m, sizeof(*evl));
                if (m == NULL)
                        return (NULL);
        }

        /*
         * Transform the Ethernet header into an Ethernet header
         * with 802.1Q encapsulation.
         */
        evl = mtod(m, struct ether_vlan_header *);
        bcopy((char *)evl + ETHER_VLAN_ENCAP_LEN,
            (char *)evl, ETHER_HDR_LEN - ETHER_TYPE_LEN);
        evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
        evl->evl_tag = htons(tag);
        return (m);
}