/*

 *  $Id: libnet_build_arp.c,v 1.13 2004/04/13 17:32:28 mike Exp $

 *

 *  libnet

 *  libnet_build_arp.c - ARP packet 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.

 *

 */

#if (HAVE_CONFIG_H)

#include "../include/config.h"

#endif

#if (!(_WIN32) || (__CYGWIN__)) 

#include "../include/libnet.h"

#else

#include "../include/win32/libnet.h"

#endif

libnet_ptag_t

libnet_build_arp(uint16_t hrd, uint16_t pro, uint8_t hln, uint8_t pln,

uint16_t op, const uint8_t *sha, const uint8_t *spa, const uint8_t *tha, const uint8_t *tpa,

const uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)

{

    uint32_t n, h;

    libnet_pblock_t *p;

    struct libnet_arp_hdr arp_hdr;

    if (l == NULL)

    { 

        return (-1); 

    }

    n = LIBNET_ARP_H + (2 * hln) + (2 * pln) + payload_s;

    h = 0;  /* ARP headers have no checksum */

    /*

     *  Find the existing protocol block if a ptag is specified, or create

     *  a new one.

     */

    p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_ARP_H);

    if (p == NULL)

    {

        return (-1);

    }

    memset(&arp_hdr, 0, sizeof(arp_hdr));

    arp_hdr.ar_hrd = htons(hrd);       /* hardware address type */

    arp_hdr.ar_pro = htons(pro);       /* protocol address type */

    arp_hdr.ar_hln = hln;              /* hardware address length */

    arp_hdr.ar_pln = pln;              /* protocol address length */

    arp_hdr.ar_op  = htons(op);        /* opcode command */

    n = libnet_pblock_append(l, p, (uint8_t *)&arp_hdr, LIBNET_ARP_H);

    if (n == -1)

    {

        /* err msg set in libnet_pblock_append() */

        goto bad; 

    }

    n = libnet_pblock_append(l, p, sha, hln);

    if (n == -1)

    {

        /* err msg set in libnet_pblock_append() */

        goto bad;

    }

    n = libnet_pblock_append(l, p, spa, pln);

    if (n == -1)

    {

        /* err msg set in libnet_pblock_append() */

        goto bad;

    }

    n = libnet_pblock_append(l, p, tha, hln);

    if (n == -1)

    {

        /* err msg set in libnet_pblock_append() */

        goto bad;

    } 

    n = libnet_pblock_append(l, p, tpa, pln);

    if (n == -1)

    {

        /* err msg set in libnet_pblock_append() */

        goto bad;

    }

    /* boilerplate payload sanity check / append macro */

    LIBNET_DO_PAYLOAD(l, p);

    return (ptag ? ptag : libnet_pblock_update(l, p, h, LIBNET_PBLOCK_ARP_H));

bad:

    libnet_pblock_delete(l, p);

    return (-1);

}

libnet_ptag_t

libnet_autobuild_arp(uint16_t op, const uint8_t *sha, const uint8_t *spa, const uint8_t *tha,

uint8_t *tpa, libnet_t *l)

{

    u_short hrd;

    switch (l->link_type)

    {

        case 1: /* DLT_EN10MB */

            hrd = ARPHRD_ETHER;

            break;

        case 6: /* DLT_IEEE802 */

            hrd = ARPHRD_IEEE802; 

            break;

        default:

            hrd = 0;

            snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,

                    "%s(): unsupported link type\n", __func__);

            return (-1);

        /* add other link-layers */

    }

    return (libnet_build_arp(

        hrd,                                    /* hardware addr */

        ETHERTYPE_IP,                           /* protocol addr */

        6,                                      /* hardware addr size */

        4,                                      /* protocol addr size */

        op,                                     /* operation type */

        sha,                                    /* sender hardware addr */

        spa,                                    /* sender protocol addr */

        tha,                                    /* target hardware addr */

        tpa,                                    /* target protocol addr */

        NULL,                                   /* payload */

        0,                                      /* payload size */

        l,                                      /* libnet context */

        0));                                    /* libnet id */

}

/* EOF */