/*
 *  $Id: libnet_build_isl.c,v 1.10 2004/04/13 17:32:28 mike Exp $
 *
 *  libnet
 *  libnet_build_isl.c - cisco's inter-switch link assembler
 *
 *  Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com>
 *  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.
 *
 * 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 "common.h"

libnet_ptag_t
libnet_build_isl(uint8_t *dhost, uint8_t type, uint8_t user,
uint8_t *shost, uint16_t len, const uint8_t *snap, uint16_t vid,
uint16_t portindex, uint16_t reserved, const uint8_t *payload,
uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
    uint32_t n;
    libnet_pblock_t *p;
    struct libnet_isl_hdr isl_hdr;

    if (l == NULL)
    {
        return (-1);
    }

    n = LIBNET_ISL_H + payload_s;           /* size of memory block */

    /*
     *  Find the existing protocol block if a ptag is specified, or create
     *  a new one.
     */
    p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_ISL_H);
    if (p == NULL)
    {
        return (-1);
    }

    memset(&isl_hdr, 0, sizeof (isl_hdr));
    memcpy(&isl_hdr.isl_dhost, dhost, sizeof(isl_hdr.isl_dhost));
    isl_hdr.isl_type    = type;
    isl_hdr.isl_user    = user;
    memcpy(&isl_hdr.isl_shost, shost, sizeof(isl_hdr.isl_shost));
    isl_hdr.isl_len     = htons(len);
    memcpy(&isl_hdr.isl_snap, snap, sizeof(isl_hdr.isl_snap));
    isl_hdr.isl_vid     = htons(vid);
    isl_hdr.isl_index   = htons(portindex);
    isl_hdr.isl_reserved= htons(reserved);

    n = libnet_pblock_append(l, p, (uint8_t *)&isl_hdr, LIBNET_ISL_H);
    if (n == -1)
    {
        goto bad;
    }

    /* boilerplate payload sanity check / append macro */
    LIBNET_DO_PAYLOAD(l, p);

    /* we need to compute the CRC for the ethernet frame and the ISL frame */
    libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
    return (ptag ? ptag : libnet_pblock_update(l, p, LIBNET_ISL_H,
            LIBNET_PBLOCK_ISL_H));
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}

/* EOF */
