/*

 *  $Id: ntp.c,v 1.3 2004/02/20 18:53:49 mike Exp $

 *

 *  libnet 1.1

 *  Build an NTP Packet

 *

 *  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

#include "./libnet_test.h"

int

main(int argc, char **argv)

{

    int c;

    libnet_t *l;

    u_long dst_ip;

    libnet_ptag_t t;

    char errbuf[LIBNET_ERRBUF_SIZE];

    printf("libnet 1.1 NTP packet shaping[raw -- autobuilding IP]\n");

    /*

     *  Initialize the library.  Root priviledges are required.

     */

    l = libnet_init(

            LIBNET_RAW4,                            /* injection type */

            NULL,                                   /* network interface */

            errbuf);                                /* error buf */

    if (l == NULL)

    {

        fprintf(stderr, "libnet_init() failed: %s", errbuf);

        exit(EXIT_FAILURE);

    }

    dst_ip  = 0;

    while((c = getopt(argc, argv, "d:")) != EOF)

    {

        switch (c)

        {

            /*

             *  We expect the input to be of the form `ip.ip.ip.ip.port`.  We

             *  point cp to the last dot of the IP address/port string and

             *  then seperate them with a NULL byte.  The optarg now points to

             *  just the IP address, and cp points to the port.

             */

            case 'd':

                if ((dst_ip = libnet_name2addr4(l, optarg, LIBNET_RESOLVE)) == -1)

                {

                    fprintf(stderr, "Bad destination IP address: %s\n", optarg);

                    exit(1);

                }

                break;

        }

    }

    if (!dst_ip)

    {

        usage(argv[0]);

        exit(EXIT_FAILURE);

    }

    /*

     *  Build the packet, remmebering that order IS important.  We must

     *  build the packet from lowest protocol type on up as it would

     *  appear on the wire.  So for our NTP packet:

     *

     *  --------------------------------------------------------------------

     *  |      IP           |  UDP   |              NTP                    |   

     *  --------------------------------------------------------------------

     *         ^                 ^                      ^

     *         |--------------   |                      |

     *  libnet_build_ipv4()--|   |                      |

     *                           |                      |

     *  libnet_build_udp()-------|                      |

     *                                                  |

     *  libnet_build_ntp()------------------------------|

     */

    t = libnet_build_ntp(

        LIBNET_NTP_LI_AC,                           /* leap indicator */

        LIBNET_NTP_VN_4,                            /* version */

        LIBNET_NTP_MODE_S,                          /* mode */

        LIBNET_NTP_STRATUM_PRIMARY,                 /* stratum */

        4,                                          /* poll interval */

        1,                                          /* precision */

        0xffff,                                     /* delay interval */

        0xffff,                                     /* delay fraction */

        0xffff,                                     /* dispersion interval */

        0xffff,                                     /* dispersion fraction */

        LIBNET_NTP_REF_PPS,                         /* reference id */

        0x11,                                       /* reference ts int */

        0x22,                                       /* reference ts frac */

        0x33,                                       /* originate ts int */

        0x44,                                       /* originate ts frac */

        0x55,                                       /* receive ts int */

        0x66,                                       /* receive ts frac */

        0x77,                                       /* transmit ts interval */

        0x88,                                       /* transmit ts fraction */

        NULL,                                       /* payload */

        0,                                          /* payload size */

        l,                                          /* libnet handle */

        0);                                         /* libnet id */

    if (t == -1)

    {

        fprintf(stderr, "Can't build NTP header: %s\n", libnet_geterror(l));

        goto bad;

    }

    libnet_seed_prand(l);

    t = libnet_build_udp(

        libnet_get_prand(LIBNET_PRu16),             /* source port */

        123,                                        /* NTP port */

        LIBNET_UDP_H + LIBNET_NTP_H,                /* UDP packet length */

        0,                                          /* checksum */

        NULL,                                       /* payload */

        0,                                          /* payload size */

        l,                                          /* libnet handle */

        0);                                         /* libnet id */

    if (t == -1)

    {

        fprintf(stderr, "Can't build UDP header: %s\n", libnet_geterror(l));

        goto bad;

    }

    t = libnet_autobuild_ipv4(

        LIBNET_IPV4_H + LIBNET_UDP_H + LIBNET_NTP_H,/* packet length */

        IPPROTO_UDP,

        dst_ip,

        l);

    if (t == -1)

    {

        fprintf(stderr, "Can't build IP header: %s\n", libnet_geterror(l));

        goto bad;

    }

    /*

     *  Write it to the wire.

     */

    fprintf(stderr, "l contains a %d byte packet\n", libnet_getpacket_size(l));

    c = libnet_write(l);

    if (c == -1)

    {

        fprintf(stderr, "Write error: %s\n", libnet_geterror(l));

        goto bad;

    }

    else

    {

        fprintf(stderr, "Wrote %d byte NTP packet; check the wire.\n", c);

    }

    libnet_destroy(l);

    return (EXIT_SUCCESS);

bad:

    libnet_destroy(l);

    return (EXIT_FAILURE);

}

void

usage(char *name)

{

    fprintf(stderr,

        "usage: %s -d destination_ip\n",

        name);

}

/* EOF */