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/*
Shared library add-on to iptables to add PSD support
Copyright (C) 2000,2001 astaro AG
This file is distributed under the terms of the GNU General Public
License (GPL). Copies of the GPL can be obtained from:
ftp://prep.ai.mit.edu/pub/gnu/GPL
2000-05-04 Markus Hennig <hennig@astaro.de> : initial
2000-08-18 Dennis Koslowski <koslowski@astaro.de> : first release
2000-12-01 Dennis Koslowski <koslowski@astaro.de> : UDP scans detection added
2001-02-04 Jan Rekorajski <baggins@pld.org.pl> : converted from target to match
*/
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_psd.h>
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"psd v%s options:\n"
" --psd-weight-threshold threshhold Portscan detection weight threshold\n\n"
" --psd-delay-threshold delay Portscan detection delay threshold\n\n"
" --psd-lo-ports-weight lo Privileged ports weight\n\n"
" --psd-hi-ports-weight hi High ports weight\n\n",
NETFILTER_VERSION);
}
static struct option opts[] = {
{ "psd-weight-threshold", 1, 0, '1' },
{ "psd-delay-threshold", 1, 0, '2' },
{ "psd-lo-ports-weight", 1, 0, '3' },
{ "psd-hi-ports-weight", 1, 0, '4' },
{ 0 }
};
/* Initialize the target. */
static void
init(struct ipt_entry_match *m, unsigned int *nfcache)
{
struct ipt_psd_info *psdinfo = (struct ipt_psd_info *)m->data;
psdinfo->weight_threshold = SCAN_WEIGHT_THRESHOLD;
psdinfo->delay_threshold = SCAN_DELAY_THRESHOLD;
psdinfo->lo_ports_weight = PORT_WEIGHT_PRIV;
psdinfo->hi_ports_weight = PORT_WEIGHT_HIGH;
/* Can't cache this */
*nfcache |= NFC_UNKNOWN;
}
typedef struct _code {
char *c_name;
int c_val;
} CODE;
#define IPT_PSD_OPT_CTRESH 0x01
#define IPT_PSD_OPT_DTRESH 0x02
#define IPT_PSD_OPT_LPWEIGHT 0x04
#define IPT_PSD_OPT_HPWEIGHT 0x08
/* Function which parses command options; returns true if it
ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
unsigned int *nfcache,
struct ipt_entry_match **match)
{
struct ipt_psd_info *psdinfo = (struct ipt_psd_info *)(*match)->data;
unsigned int num;
char storage[strlen(optarg) + 2];
/* string_to_number needs a leading space */
storage[0] = ' ';
strcpy(&storage[1], optarg);
switch (c) {
/* PSD-weight-threshold */
case '1':
if (*flags & IPT_PSD_OPT_CTRESH)
exit_error(PARAMETER_PROBLEM,
"Can't specify --psd-weight-threshold "
"twice");
if (string_to_number(storage, 0, 10000, &num) == -1)
exit_error(PARAMETER_PROBLEM,
"bad --psd-weight-threshold `%s'", optarg);
psdinfo->weight_threshold = num;
*flags |= IPT_PSD_OPT_CTRESH;
break;
/* PSD-delay-threshold */
case '2':
if (*flags & IPT_PSD_OPT_DTRESH)
exit_error(PARAMETER_PROBLEM,
"Can't specify --psd-delay-threshold twice");
if (string_to_number(storage, 0, 10000, &num) == -1)
exit_error(PARAMETER_PROBLEM,
"bad --psd-delay-threshold `%s'", optarg);
psdinfo->delay_threshold = num;
*flags |= IPT_PSD_OPT_DTRESH;
break;
/* PSD-lo-ports-weight */
case '3':
if (*flags & IPT_PSD_OPT_LPWEIGHT)
exit_error(PARAMETER_PROBLEM,
"Can't specify --psd-lo-ports-weight twice");
if (string_to_number(storage, 0, 10000, &num) == -1)
exit_error(PARAMETER_PROBLEM,
"bad --psd-lo-ports-weight `%s'", optarg);
psdinfo->lo_ports_weight = num;
*flags |= IPT_PSD_OPT_LPWEIGHT;
break;
/* PSD-hi-ports-weight */
case '4':
if (*flags & IPT_PSD_OPT_HPWEIGHT)
exit_error(PARAMETER_PROBLEM,
"Can't specify --psd-hi-ports-weight twice");
if (string_to_number(storage, 0, 10000, &num) == -1)
exit_error(PARAMETER_PROBLEM,
"bad --psd-hi-ports-weight `%s'", optarg);
psdinfo->hi_ports_weight = num;
*flags |= IPT_PSD_OPT_HPWEIGHT;
break;
default:
return 0;
}
return 1;
}
/* Final check; nothing. */
static void final_check(unsigned int flags)
{
}
/* Prints out the targinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_match *match,
int numeric)
{
const struct ipt_psd_info *psdinfo
= (const struct ipt_psd_info *)match->data;
printf("psd ");
printf("weight-threshold: %u ",psdinfo->weight_threshold);
printf("delay-threshold: %u ",psdinfo->delay_threshold);
printf("lo-ports-weight: %u ",psdinfo->lo_ports_weight);
printf("hi-ports-weight: %u ",psdinfo->hi_ports_weight);
}
/* Saves the union ipt_targinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
const struct ipt_psd_info *psdinfo
= (const struct ipt_psd_info *)match->data;
printf("--psd-weight-threshold %u ", psdinfo->weight_threshold);
printf("--psd-delay-threshold %u ", psdinfo->delay_threshold);
printf("--psd-lo-ports-weight %u ",psdinfo->lo_ports_weight);
printf("--psd-hi-ports-weight %u ",psdinfo->hi_ports_weight);
}
static
struct iptables_match psd
= { NULL,
"psd",
NETFILTER_VERSION,
IPT_ALIGN(sizeof(struct ipt_psd_info)),
IPT_ALIGN(sizeof(struct ipt_psd_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_match(&psd);
}
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