The following two source files comprise the Legerdemain codebase. To preserve readability, we richly comment the code but no book-text appears inside the code. You can download the full source files from this book's companion Web site at http://www.wiley.com/compbooks/schiffman.
/* * $Id: legerdemain.h,v 1.1.1.1 2002/02/18 21:30:06 route Exp $ * * Building Open Source Network Security Tools * legerdemain.h - libsf example code * * Copyright (c) 2002 Mike D. Schiffman <mike@infonexus.com> * All rights reserved. * */ #include <libsf.h> void usage(char *); /* EOF */
/*
* $Id: legerdemain.c,v 1.1.1.1 2002/02/18 21:30:06 route Exp $ i
*
* Building Open Source Network Security Tools
* legerdemain.c - libsf example code
*
* Copyright (c) 2002 Mike D. Schiffman <mike@infonexus.com>
* All rights reserved.
*
*/
#include "./legerdemain.h"
int
main(int argc, char *argv[])
{
int c;
int dump_all_guesses;
libsf_t *s;
char *guess;
char *device;
u_char flags;
u_short hs, tm;
char errbuf[LIBSF_ERRBUF_SIZE];
printf("Legerdemain 1.0 [remote operating system detection tool]\n");
flags = 0;
device = NULL;
dump_all_guesses = 0;
while ((c = getopt(argc, argv, "adi:v")) != EOF)
{
switch (c)
{
case 'a':
dump_all_guesses = 1;
break;
case 'd':
flags = LIBSF_CTRL_DEBUG;
break;
case 'i':
device = optarg;
break;
case 'v':
flags = LIBSF_CTRL_VERBOSE;
break;
default:
break;
}
}
c = argc - optind;
if (c != 1)
{
usage(argv[0]);
return (EXIT_FAILURE);
}
/*
* Initialize libsf with the following options:
*
* LIBSF_ACTIVE - An active fingerprint scan.
* device - Use the device the user specified at the command
* line or let libsf (libnet) determine a device.
* argv[options]- User specified target IP address.
* 0 - Probe for an open TCP port (portscan)
* 1 - Use 1 as a closed TCP port.
* flags - User speficied flags.
* errbuf - Holds any possible initialization errors.
*/
s =libsf_init(LIBSF_ACTIVE, device, argv[optind], 0, 1, flags,
errbuf);
if (s == NULL)
{
fprintf(stderr, "error creating libsf handle: %s\n", errbuf);
return (EXIT_FAILURE);
}
printf("Host: %s, found open port: %d and closed port: %d\n",
argv[optind], s->t.port_open, s->t.port_closed);
printf("Performing active fingerprint scan...\n");
/*
* Perform the active scan, trying each one of the seven active
* fingerprint tests. Note that the function only returns -1 on
* error (if s was a NULL pointer), not when some or all of the
* fingerprint tests timeout or do not succeed.
*/
if (libsf_active_id(s)== -1)
{
fprintf(stderr, "libsf_active_id %s\n", libsf_geterror(s));
}
else
{
/* get the total number of matches */
tm = libsf_os_get_tm(s);
/* get the highest scored match */
hs = libsf_os_get_hs(s);
printf("%d potential matches (highest score of %d)\ n", tm, hs);
printf("Highest scored OS guesses:\ n");
/* run through the 0s list, dumping string that matches score */
while ((guess = libsf_os_get_match(s, hs)))
{
printf("%s\n", guess);
}
/* if invoked with the 'a' switch, dump entire OS list */
if (dump_all_guesses)
{
printf("All OS guesses:\n");
/* reset the internal OS list counter */
libsf_os_reset_counter(s);
/* dump each guess from the list */
while ((guess = libsf_os_get_next(s)))
{
printf("%s\n", guess);
}
}
}
/* free everything up */
libsf_destroy(s);
return (EXIT_SUCCESS);
}
void
usage(char *name)
{
fprintf(stderr, "usage %s {options] target n"
"-a\t\tdump all guesses\n"
"-d\t\tdump debugging information\n"
"-i device\tspecify a device\n"
"-v t\tbe\verbose\n", name);
}
/* EOF */