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/* Shared library add-on to iptables to add string matching support.
*
* Copyright (C) 2000 Emmanuel Roger <winfield@freegates.be>
*/
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ipt_string.h>
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"STRING match v%s options:\n"
"--string [!] string Match a string in a packet\n",
NETFILTER_VERSION);
fputc('\n', stdout);
}
static struct option opts[] = {
{ "string", 1, 0, '1' },
{0}
};
/* Initialize the match. */
static void
init(struct ipt_entry_match *m, unsigned int *nfcache)
{
*nfcache |= NFC_UNKNOWN;
}
static void
parse_string(const unsigned char *s, struct ipt_string_info *info)
{
if (strlen(s) <= 255) strcpy(info->string, s);
else exit_error(PARAMETER_PROBLEM, "STRING too long `%s'", s);
}
/* 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_string_info *stringinfo = (struct ipt_string_info *)(*match)->data;
switch (c) {
case '1':
if (check_inverse(optarg, &invert))
optind++;
parse_string(argv[optind-1], stringinfo);
if (invert)
stringinfo->invert = 1;
*flags = 1;
break;
default:
return 0;
}
return 1;
}
static void
print_string(char string[], int invert, int numeric)
{
if (invert)
fputc('!', stdout);
printf("%s ",string);
}
/* Final check; must have specified --string. */
static void
final_check(unsigned int flags)
{
if (!flags)
exit_error(PARAMETER_PROBLEM,
"STRING match: You must specify `--string'");
}
/* Prints out the matchinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_match *match,
int numeric)
{
printf("STRING match ");
print_string(((struct ipt_string_info *)match->data)->string,
((struct ipt_string_info *)match->data)->invert, numeric);
}
/* Saves the union ipt_matchinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
printf("--tos ");
print_string(((struct ipt_string_info *)match->data)->string,
((struct ipt_string_info *)match->data)->invert, 0);
}
struct iptables_match string
= { NULL,
"string",
NETFILTER_VERSION,
IPT_ALIGN(sizeof(struct ipt_string_info)),
IPT_ALIGN(sizeof(struct ipt_string_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_match(&string);
}
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