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/* Shared library add-on to iptables for ECN, $Version$
*
* (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
*
* $Id: libipt_ECN.c,v 1.11 2002/08/07 10:04:42 laforge Exp $
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ECN.h>
static void init(struct ipt_entry_target *t, unsigned int *nfcache)
{
}
static void help(void)
{
printf(
"ECN target v%s options\n"
" --ecn-tcp-remove Remove all ECN bits from TCP header\n",
IPTABLES_VERSION);
}
#if 0
"ECN target v%s EXPERIMENTAL options (use with extreme care!)\n"
" --ecn-ip-ect Set the IPv4 ECT codepoint (0 to 3)\n"
" --ecn-tcp-cwr Set the IPv4 CWR bit (0 or 1)\n"
" --ecn-tcp-ece Set the IPv4 ECE bit (0 or 1)\n",
#endif
static struct option opts[] = {
{ "ecn-tcp-remove", 0, 0, 'F' },
{ "ecn-tcp-cwr", 1, 0, 'G' },
{ "ecn-tcp-ece", 1, 0, 'H' },
{ "ecn-ip-ect", 1, 0, '9' },
{ 0 }
};
static int
parse(int c, char **argv, int invert, unsigned int *flags,
const struct ipt_entry *entry,
struct ipt_entry_target **target)
{
unsigned int result;
struct ipt_ECN_info *einfo
= (struct ipt_ECN_info *)(*target)->data;
switch (c) {
case 'F':
if (*flags)
exit_error(PARAMETER_PROBLEM,
"ECN target: Only use --ecn-tcp-remove ONCE!");
einfo->operation = IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR;
einfo->proto.tcp.ece = 0;
einfo->proto.tcp.cwr = 0;
*flags = 1;
break;
case 'G':
if (*flags & IPT_ECN_OP_SET_CWR)
exit_error(PARAMETER_PROBLEM,
"ECN target: Only use --ecn-tcp-cwr ONCE!");
if (string_to_number(optarg, 0, 1, &result))
exit_error(PARAMETER_PROBLEM,
"ECN target: Value out of range");
einfo->operation |= IPT_ECN_OP_SET_CWR;
einfo->proto.tcp.cwr = result;
*flags |= IPT_ECN_OP_SET_CWR;
break;
case 'H':
if (*flags & IPT_ECN_OP_SET_ECE)
exit_error(PARAMETER_PROBLEM,
"ECN target: Only use --ecn-tcp-ece ONCE!");
if (string_to_number(optarg, 0, 1, &result))
exit_error(PARAMETER_PROBLEM,
"ECN target: Value out of range");
einfo->operation |= IPT_ECN_OP_SET_ECE;
einfo->proto.tcp.ece = result;
*flags |= IPT_ECN_OP_SET_ECE;
break;
case '9':
if (*flags & IPT_ECN_OP_SET_IP)
exit_error(PARAMETER_PROBLEM,
"ECN target: Only use --ecn-ip-ect ONCE!");
if (string_to_number(optarg, 0, 3, &result))
exit_error(PARAMETER_PROBLEM,
"ECN target: Value out of range");
einfo->operation |= IPT_ECN_OP_SET_IP;
einfo->ip_ect = result;
*flags |= IPT_ECN_OP_SET_IP;
break;
default:
return 0;
}
return 1;
}
static void
final_check(unsigned int flags)
{
if (!flags)
exit_error(PARAMETER_PROBLEM,
"ECN target: Parameter --ecn-tcp-remove is required");
}
/* Prints out the targinfo. */
static void
print(const struct ipt_ip *ip,
const struct ipt_entry_target *target,
int numeric)
{
const struct ipt_ECN_info *einfo =
(const struct ipt_ECN_info *)target->data;
printf("ECN ");
if (einfo->operation == (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)
&& einfo->proto.tcp.ece == 0
&& einfo->proto.tcp.cwr == 0)
printf("TCP remove ");
else {
if (einfo->operation & IPT_ECN_OP_SET_ECE)
printf("ECE=%u ", einfo->proto.tcp.ece);
if (einfo->operation & IPT_ECN_OP_SET_CWR)
printf("CWR=%u ", einfo->proto.tcp.cwr);
if (einfo->operation & IPT_ECN_OP_SET_IP)
printf("ECT codepoint=%u ", einfo->ip_ect);
}
}
/* Saves the union ipt_targinfo in parsable form to stdout. */
static void
save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
{
const struct ipt_ECN_info *einfo =
(const struct ipt_ECN_info *)target->data;
if (einfo->operation == (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)
&& einfo->proto.tcp.ece == 0
&& einfo->proto.tcp.cwr == 0)
printf("--ecn-tcp-remove ");
else {
if (einfo->operation & IPT_ECN_OP_SET_ECE)
printf("--ecn-tcp-ece %d ", einfo->proto.tcp.ece);
if (einfo->operation & IPT_ECN_OP_SET_CWR)
printf("--ecn-tcp-cwr %d ", einfo->proto.tcp.cwr);
if (einfo->operation & IPT_ECN_OP_SET_IP)
printf("--ecn-ip-ect %d ", einfo->ip_ect);
}
}
static
struct iptables_target ecn
= { NULL,
"ECN",
IPTABLES_VERSION,
IPT_ALIGN(sizeof(struct ipt_ECN_info)),
IPT_ALIGN(sizeof(struct ipt_ECN_info)),
&help,
&init,
&parse,
&final_check,
&print,
&save,
opts
};
void _init(void)
{
register_target(&ecn);
}
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