/* 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

 */

#include <stdio.h>

#include <xtables.h>

#include <linux/netfilter_ipv4/ipt_ECN.h>

enum {

	O_ECN_TCP_REMOVE = 0,

	O_ECN_TCP_CWR,

	O_ECN_TCP_ECE,

	O_ECN_IP_ECT,

	F_ECN_TCP_REMOVE = 1 << O_ECN_TCP_REMOVE,

	F_ECN_TCP_CWR    = 1 << O_ECN_TCP_CWR,

	F_ECN_TCP_ECE    = 1 << O_ECN_TCP_ECE,

};

static void ECN_help(void)

{

	printf(

"ECN target options\n"

"  --ecn-tcp-remove		Remove all ECN bits from TCP header\n");

}

#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 const struct xt_option_entry ECN_opts[] = {

	{.name = "ecn-tcp-remove", .id = O_ECN_TCP_REMOVE, .type = XTTYPE_NONE,

	 .excl = F_ECN_TCP_CWR | F_ECN_TCP_ECE},

	{.name = "ecn-tcp-cwr", .id = O_ECN_TCP_CWR, .type = XTTYPE_UINT8,

	 .min = 0, .max = 1, .excl = F_ECN_TCP_REMOVE},

	{.name = "ecn-tcp-ece", .id = O_ECN_TCP_ECE, .type = XTTYPE_UINT8,

	 .min = 0, .max = 1, .excl = F_ECN_TCP_REMOVE},

	{.name = "ecn-ip-ect", .id = O_ECN_IP_ECT, .type = XTTYPE_UINT8,

	 .min = 0, .max = 3},

	XTOPT_TABLEEND,

};

static void ECN_parse(struct xt_option_call *cb)

{

	struct ipt_ECN_info *einfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_ECN_TCP_REMOVE:

		einfo->operation = IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR;

		einfo->proto.tcp.ece = 0;

		einfo->proto.tcp.cwr = 0;

		break;

	case O_ECN_TCP_CWR:

		einfo->operation |= IPT_ECN_OP_SET_CWR;

		einfo->proto.tcp.cwr = cb->val.u8;

		break;

	case O_ECN_TCP_ECE:

		einfo->operation |= IPT_ECN_OP_SET_ECE;

		einfo->proto.tcp.ece = cb->val.u8;

		break;

	case O_ECN_IP_ECT:

		einfo->operation |= IPT_ECN_OP_SET_IP;

		einfo->ip_ect = cb->val.u8;

		break;

	}

}

static void ECN_check(struct xt_fcheck_call *cb)

{

	if (cb->xflags == 0)

		xtables_error(PARAMETER_PROBLEM,

		           "ECN target: An operation is required");

}

static void ECN_print(const void *ip, const struct xt_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);

	}

}

static void ECN_save(const void *ip, const struct xt_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 xtables_target ecn_tg_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,

	.print		= ECN_print,

	.save		= ECN_save,

	.x6_parse	= ECN_parse,

	.x6_fcheck	= ECN_check,

	.x6_options	= ECN_opts,

};

void _init(void)

{

	xtables_register_target(&ecn_tg_reg);

}