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/*
* $Id: libnet-example-2.c,v 1.1.1.1 2000/05/25 00:28:49 route Exp $
*
* libnet example code
* example 2: link-layer api / ICMP hostmask packet
*
* Copyright (c) 1998 - 2001 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 <libnet.h>
void usage(char *);
u_char enet_src[6] = {0x0d, 0x0e, 0x0a, 0x0d, 0x00, 0x00};
u_char enet_dst[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
int
main(int argc, char *argv[])
{
int packet_size, /* size of our packet */
c; /* misc */
u_long src_ip, dst_ip; /* source ip, dest ip */
u_char *packet; /* pointer to our packet buffer */
char err_buf[LIBNET_ERRBUF_SIZE]; /* error buffer */
u_char *device; /* pointer to the device to use */
struct libnet_link_int *network; /* pointer to link interface struct */
printf("libnet example code:\tmodule 2\n\n");
printf("packet injection interface:\tlink layer\n");
printf("packet type:\t\t\tICMP net mask [no payload]\n");
device = NULL;
src_ip = 0;
dst_ip = 0;
while ((c = getopt(argc, argv, "i:d:s:")) != EOF)
{
switch (c)
{
case 'd':
if (!(dst_ip = libnet_name_resolve(optarg, LIBNET_RESOLVE)))
{
libnet_error(LIBNET_ERR_FATAL, "Bad destination IP address: %s\n", optarg);
}
break;
case 'i':
device = optarg;
break;
case 's':
if (!(src_ip = libnet_name_resolve(optarg, LIBNET_RESOLVE)))
{
libnet_error(LIBNET_ERR_FATAL, "Bad source IP address: %s\n", optarg);
}
break;
default:
exit(EXIT_FAILURE);
}
}
if (!src_ip || !dst_ip)
{
usage(argv[0]);
exit(EXIT_FAILURE);
}
/*
* Step 1: Network Initialization (interchangable with step 2).
*/
if (device == NULL)
{
struct sockaddr_in sin;
/*
* Try to locate a device.
*/
if (libnet_select_device(&sin, &device, err_buf) == -1)
{
libnet_error(LIBNET_ERR_FATAL, "libnet_select_device failed: %s\n", err_buf);
}
printf("device:\t\t\t\t%s\n", device);
}
if ((network = libnet_open_link_interface(device, err_buf)) == NULL)
{
libnet_error(LIBNET_ERR_FATAL, "libnet_open_link_interface: %s\n", err_buf);
}
/*
* We're going to build an ICMP packet with no payload using the
* link-layer API, so this time we need memory for a ethernet header
* as well as memory for the ICMP and IP headers.
*/
packet_size = LIBNET_IP_H + LIBNET_ETH_H + LIBNET_ICMP_MASK_H;
/*
* Step 2: Memory Initialization (interchangable with step 1).
*/
if (libnet_init_packet(packet_size, &packet) == -1)
{
libnet_error(LIBNET_ERR_FATAL, "libnet_init_packet failed\n");
}
/*
* Step 3: Packet construction (ethernet header).
*/
libnet_build_ethernet(enet_dst,
enet_src,
ETHERTYPE_IP,
NULL,
0,
packet);
/*
* Step 3: Packet construction (IP header).
*/
libnet_build_ip(ICMP_MASK_H,
0, /* IP tos */
242, /* IP ID */
0, /* Frag */
64, /* TTL */
IPPROTO_ICMP, /* Transport protocol */
src_ip, /* Source IP */
dst_ip, /* Destination IP */
NULL, /* Pointer to payload (none) */
0,
packet + LIBNET_ETH_H); /* Packet header memory */
/*
* Step 3: Packet construction (ICMP header).
*/
libnet_build_icmp_mask(ICMP_MASKREPLY, /* type */
0, /* code */
242, /* id */
0, /* seq */
0xffffffff, /* mask */
NULL, /* payload */
0, /* payload_s */
packet + LIBNET_ETH_H + LIBNET_IP_H);
/*
* Step 4: Packet checksums (ICMP header *AND* IP header).
*/
if (libnet_do_checksum(packet + ETH_H, IPPROTO_ICMP, LIBNET_ICMP_MASK_H) == -1)
{
libnet_error(LIBNET_ERR_FATAL, "libnet_do_checksum failed\n");
}
if (libnet_do_checksum(packet + ETH_H, IPPROTO_IP, LIBNET_IP_H) == -1)
{
libnet_error(LIBNET_ERR_FATAL, "libnet_do_checksum failed\n");
}
/*
* Step 5: Packet injection.
*/
c = libnet_write_link_layer(network, device, packet, packet_size);
if (c < packet_size)
{
libnet_error(LN_ERR_WARNING, "libnet_write_link_layer only wrote %d bytes\n", c);
}
else
{
printf("construction and injection completed, wrote all %d bytes\n", c);
}
/*
* Shut down the interface.
*/
if (libnet_close_link_interface(network) == -1)
{
libnet_error(LN_ERR_WARNING, "libnet_close_link_interface couldn't close the interface");
}
/*
* Free packet memory.
*/
libnet_destroy_packet(&packet);
return (c == -1 ? EXIT_FAILURE : EXIT_SUCCESS);
}
void
usage(char *name)
{
fprintf(stderr, "usage: %s [-i interface] -s s_ip -d d_ip\n", name);
}
/* EOF */
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