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/* Shared library add-on to iptables for ECN matching
*
* (C) 2002 by Harald Welte <laforge@gnumonks.org>
*
* This program is distributed under the terms of GNU GPL v2, 1991
*
* libipt_ecn.c borrowed heavily from libipt_dscp.c
*
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ecn.h>
static void ecn_help(void)
{
printf(
"ECN match options\n"
"[!] --ecn-tcp-cwr Match CWR bit of TCP header\n"
"[!] --ecn-tcp-ece Match ECE bit of TCP header\n"
"[!] --ecn-ip-ect [0..3] Match ECN codepoint in IPv4 header\n");
}
static const struct option ecn_opts[] = {
{ .name = "ecn-tcp-cwr", .has_arg = 0, .val = 'F' },
{ .name = "ecn-tcp-ece", .has_arg = 0, .val = 'G' },
{ .name = "ecn-ip-ect", .has_arg = 1, .val = 'H' },
{ .name = NULL }
};
static int ecn_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
unsigned int result;
struct ipt_ecn_info *einfo
= (struct ipt_ecn_info *)(*match)->data;
switch (c) {
case 'F':
if (*flags & IPT_ECN_OP_MATCH_CWR)
exit_error(PARAMETER_PROBLEM,
"ECN match: can only use parameter ONCE!");
xtables_check_inverse(optarg, &invert, &optind, 0);
einfo->operation |= IPT_ECN_OP_MATCH_CWR;
if (invert)
einfo->invert |= IPT_ECN_OP_MATCH_CWR;
*flags |= IPT_ECN_OP_MATCH_CWR;
break;
case 'G':
if (*flags & IPT_ECN_OP_MATCH_ECE)
exit_error(PARAMETER_PROBLEM,
"ECN match: can only use parameter ONCE!");
xtables_check_inverse(optarg, &invert, &optind, 0);
einfo->operation |= IPT_ECN_OP_MATCH_ECE;
if (invert)
einfo->invert |= IPT_ECN_OP_MATCH_ECE;
*flags |= IPT_ECN_OP_MATCH_ECE;
break;
case 'H':
if (*flags & IPT_ECN_OP_MATCH_IP)
exit_error(PARAMETER_PROBLEM,
"ECN match: can only use parameter ONCE!");
xtables_check_inverse(optarg, &invert, &optind, 0);
if (invert)
einfo->invert |= IPT_ECN_OP_MATCH_IP;
*flags |= IPT_ECN_OP_MATCH_IP;
einfo->operation |= IPT_ECN_OP_MATCH_IP;
if (!xtables_strtoui(optarg, NULL, &result, 0, 3))
exit_error(PARAMETER_PROBLEM,
"ECN match: Value out of range");
einfo->ip_ect = result;
break;
default:
return 0;
}
return 1;
}
static void ecn_check(unsigned int flags)
{
if (!flags)
exit_error(PARAMETER_PROBLEM,
"ECN match: some option required");
}
static void ecn_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct ipt_ecn_info *einfo =
(const struct ipt_ecn_info *)match->data;
printf("ECN match ");
if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
if (einfo->invert & IPT_ECN_OP_MATCH_ECE)
fputc('!', stdout);
printf("ECE ");
}
if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
if (einfo->invert & IPT_ECN_OP_MATCH_CWR)
fputc('!', stdout);
printf("CWR ");
}
if (einfo->operation & IPT_ECN_OP_MATCH_IP) {
if (einfo->invert & IPT_ECN_OP_MATCH_IP)
fputc('!', stdout);
printf("ECT=%d ", einfo->ip_ect);
}
}
static void ecn_save(const void *ip, const struct xt_entry_match *match)
{
const struct ipt_ecn_info *einfo =
(const struct ipt_ecn_info *)match->data;
if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
if (einfo->invert & IPT_ECN_OP_MATCH_ECE)
printf("! ");
printf("--ecn-tcp-ece ");
}
if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
if (einfo->invert & IPT_ECN_OP_MATCH_CWR)
printf("! ");
printf("--ecn-tcp-cwr ");
}
if (einfo->operation & IPT_ECN_OP_MATCH_IP) {
if (einfo->invert & IPT_ECN_OP_MATCH_IP)
printf("! ");
printf("--ecn-ip-ect %d", einfo->ip_ect);
}
}
static struct xtables_match ecn_mt_reg = {
.name = "ecn",
.version = XTABLES_VERSION,
.family = NFPROTO_IPV4,
.size = XT_ALIGN(sizeof(struct ipt_ecn_info)),
.userspacesize = XT_ALIGN(sizeof(struct ipt_ecn_info)),
.help = ecn_help,
.parse = ecn_parse,
.final_check = ecn_check,
.print = ecn_print,
.save = ecn_save,
.extra_opts = ecn_opts,
};
void _init(void)
{
xtables_register_match(&ecn_mt_reg);
}
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