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/* Shared library add-on to iptables to add byte tracking support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>
#include <linux/netfilter_ipv4/ipt_connbytes.h>
/* Function which prints out usage message. */
static void
help(void)
{
printf(
"connbytes v%s options:\n"
" [!] --connbytes from:[to]\n"
" Transfered byte range to match\n"
"\n", IPTABLES_VERSION);
}
static struct option opts[] = {
{ "connbytes", 1, 0, '1' },
{0}
};
/* Initialize the match. */
static void
init(struct ipt_entry_match *m, unsigned int *nfcache)
{
/* Can't cache this */
*nfcache |= NFC_UNKNOWN;
}
static void
parse_range(const char *arg, struct ipt_connbytes_info *si)
{
char *colon,*p;
si->from = strtoul(arg,&colon,10);
if (*colon != ':')
exit_error(PARAMETER_PROBLEM, "Bad range `%s'", arg);
si->to = strtoul(colon+1,&p,10);
if (p == colon+1) {
/* second number omited */
si->to = 0xffffffff;
}
if (si->from > si->to)
exit_error(PARAMETER_PROBLEM, "%lu should be less than %lu", si->from,si->to);
}
/* 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_connbytes_info *sinfo = (struct ipt_connbytes_info *)(*match)->data;
unsigned long i;
switch (c) {
case '1':
if (check_inverse(optarg, &invert, optind, 0))
optind++;
parse_range(argv[optind-1], sinfo);
if (invert) {
i = sinfo->from;
sinfo->from = sinfo->to;
sinfo->to = i;
}
*flags = 1;
break;
default:
return 0;
}
return 1;
}
static void final_check(unsigned int flags)
{
if (!flags)
exit_error(PARAMETER_PROBLEM, "You must specify `--connbytes'");
}
/* Prints out the matchinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_match *match,
int numeric)
{
struct ipt_connbytes_info *sinfo = (struct ipt_connbytes_info *)match->data;
if (sinfo->from > sinfo->to)
printf("connbytes ! %lu:%lu ",sinfo->to,sinfo->from);
else
printf("connbytes %lu:%lu ",sinfo->from,sinfo->to);
}
/* Saves the matchinfo in parsable form to stdout. */
static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
struct ipt_connbytes_info *sinfo = (struct ipt_connbytes_info *)match->data;
if (sinfo->from > sinfo->to)
printf("! --connbytes %lu:%lu ",sinfo->to,sinfo->from);
else
printf("--connbytes %lu:%lu ",sinfo->from,sinfo->to);
}
static
struct iptables_match state
= { NULL,
"connbytes",
IPTABLES_VERSION,
IPT_ALIGN(sizeof(struct ipt_connbytes_info)),
IPT_ALIGN(sizeof(struct ipt_connbytes_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_match(&state);
}
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