/*

 *

 * libnet 1.1

 * Build a TFTP scanner using payload

 *

 * Copyright (c) 2003 Frédéric Raynal <pappy@security-labs.org>

 * All rights reserved.

 *

 * Ex:

 *    ./tftp -s 192.168.0.1 -d 192.168.0.66 -p plop

 *

 *

 * 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 src_ip, dst_ip;

    char errbuf[LIBNET_ERRBUF_SIZE];

    libnet_ptag_t udp = 0, ip = 0;

    char *filename = "/etc/passwd";

    char mode[] = "netascii";

    u_char *payload = NULL;

    uint payload_s = 0;

    printf("libnet 1.1 packet shaping: UDP + payload[raw] == TFTP\n");

    /*

     *  Initialize the library.  Root priviledges are required.

     */

    l = libnet_init(

	    LIBNET_RAW4,                  /* injection type */

            NULL,                         /* network interface */

            errbuf);                      /* error buffer */

    if (l == NULL)

    {

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

        exit(EXIT_FAILURE); 

    }

    src_ip  = 0;

    dst_ip  = 0;

    while ((c = getopt(argc, argv, "d:s:p:")) != 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);

		    goto bad;

                }

                break;

            case 's':

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

                {

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

		    goto bad;

                }

                break;

	    case 'p':

		filename = optarg;

		break;

            default:

		fprintf(stderr, "unkown option [%s]: bye bye\n", optarg);

		goto bad;

        }

    }

    if (!src_ip || !dst_ip)

    {

        usage(argv[0]);

        exit(EXIT_FAILURE);

    }

    /* 

     * build payload

     *

     *      2 bytes     string    1 byte     string   1 byte

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

     *      | Opcode |  Filename  |   0  |    Mode    |   0  |

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

     *

     */

    payload_s = 2 + strlen(filename) + 1 + strlen(mode) + 1;

    payload = malloc(sizeof(char)*payload_s);

    if (!payload)

    {

        fprintf(stderr, "malloc error for payload\n");

        goto bad;

    }

    memset(payload, 0, payload_s);

    payload[1] = 1; /* opcode - GET */

    memcpy(payload + 2, filename, strlen(filename));

    memcpy(payload + 2 +  strlen(filename) + 1 , mode, strlen(mode));

    /*

     * Build pblocks

     */

    udp = libnet_build_udp(

	0x1234,                           /* source port */

	69,                               /* destination port */

	LIBNET_UDP_H + payload_s,         /* packet length */

	0,                                /* checksum */

	payload,                          /* payload */

	payload_s,                        /* payload size */

	l,                                /* libnet handle */

	0);                               /* libnet id */

    if (udp == -1)

    {

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

	goto bad;

    }

    ip = libnet_build_ipv4(

        LIBNET_IPV4_H + LIBNET_UDP_H + payload_s, /* length - dont forget the UDP's payload */

        0,                                /* TOS */

        0x4242,                           /* IP ID */

        0,                                /* IP Frag */

        0x42,                             /* TTL */

        IPPROTO_UDP,                      /* protocol */

        0,                                /* checksum */

        src_ip,                           /* source IP */

        dst_ip,                           /* destination IP */

        NULL,                             /* payload (already in UDP) */

        0,                                /* payload size */

        l,                                /* libnet handle */

        0);                               /* libnet id */

    if (ip == -1)

    {

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

        goto bad;

    }

    /*

     *  Write it to the wire.

     */

    c = libnet_write(l);

    if (c == -1)

    {

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

        goto bad;

    }

    else

    {

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

    }

    libnet_destroy(l);

    free(payload);

    return (EXIT_SUCCESS);

bad:

    libnet_destroy(l);

    free(payload);

    return (EXIT_FAILURE);

}

void

usage(char *name)

{

    fprintf(stderr,

        "usage: %s -s source_ip -d destination_ip"

        " [-p payload] [-t|u|i] \n",

        name);

}

/* EOF */