/* Shared library add-on to iptables for ECN matching

 *

 * (C) 2002 by Harald Welte <laforge@netfilter.org>

 * (C) 2011 by Patrick McHardy <kaber@trash.net>

 *

 * 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/xt_ecn.h>

enum {

	O_ECN_TCP_CWR = 0,

	O_ECN_TCP_ECE,

	O_ECN_IP_ECT,

};

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/IPv6 header\n");

}

static const struct xt_option_entry ecn_opts[] = {

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

	 .flags = XTOPT_INVERT},

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

	 .flags = XTOPT_INVERT},

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

	 .min = 0, .max = 3, .flags = XTOPT_INVERT},

	XTOPT_TABLEEND,

};

static void ecn_parse(struct xt_option_call *cb)

{

	struct xt_ecn_info *einfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_ECN_TCP_CWR:

		einfo->operation |= XT_ECN_OP_MATCH_CWR;

		if (cb->invert)

			einfo->invert |= XT_ECN_OP_MATCH_CWR;

		break;

	case O_ECN_TCP_ECE:

		einfo->operation |= XT_ECN_OP_MATCH_ECE;

		if (cb->invert)

			einfo->invert |= XT_ECN_OP_MATCH_ECE;

		break;

	case O_ECN_IP_ECT:

		if (cb->invert)

			einfo->invert |= XT_ECN_OP_MATCH_IP;

		einfo->operation |= XT_ECN_OP_MATCH_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 match: some option required");

}

static void ecn_print(const void *ip, const struct xt_entry_match *match,

                      int numeric)

{

	const struct xt_ecn_info *einfo =

		(const struct xt_ecn_info *)match->data;

	printf(" ECN match");

	if (einfo->operation & XT_ECN_OP_MATCH_ECE) {

		printf(" %sECE",

		       (einfo->invert & XT_ECN_OP_MATCH_ECE) ? "!" : "");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_CWR) {

		printf(" %sCWR",

		       (einfo->invert & XT_ECN_OP_MATCH_CWR) ? "!" : "");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_IP) {

		printf(" %sECT=%d",

		       (einfo->invert & XT_ECN_OP_MATCH_IP) ? "!" : "",

		       einfo->ip_ect);

	}

}

static void ecn_save(const void *ip, const struct xt_entry_match *match)

{

	const struct xt_ecn_info *einfo =

		(const struct xt_ecn_info *)match->data;

	if (einfo->operation & XT_ECN_OP_MATCH_ECE) {

		if (einfo->invert & XT_ECN_OP_MATCH_ECE)

			printf(" !");

		printf(" --ecn-tcp-ece");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_CWR) {

		if (einfo->invert & XT_ECN_OP_MATCH_CWR)

			printf(" !");

		printf(" --ecn-tcp-cwr");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_IP) {

		if (einfo->invert & XT_ECN_OP_MATCH_IP)

			printf(" !");

		printf(" --ecn-ip-ect %d", einfo->ip_ect);

	}

}

static int ecn_xlate(struct xt_xlate *xl,

		     const struct xt_xlate_mt_params *params)

{

	const struct xt_ecn_info *einfo =

		(const struct xt_ecn_info *)params->match->data;

	if (einfo->operation & XT_ECN_OP_MATCH_ECE) {

		xt_xlate_add(xl, "tcp flags ");

		if (einfo->invert)

			xt_xlate_add(xl,"!= ");

		xt_xlate_add(xl, "ecn");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_CWR) {

		xt_xlate_add(xl, "tcp flags ");

		if (einfo->invert)

			xt_xlate_add(xl,"!= ");

		xt_xlate_add(xl, "cwr");

	}

	if (einfo->operation & XT_ECN_OP_MATCH_IP) {

		xt_xlate_add(xl, "ip ecn ");

		if (einfo->invert)

			xt_xlate_add(xl,"!= ");

		switch (einfo->ip_ect) {

		case 0:

			xt_xlate_add(xl, "not-ect");

			break;

		case 1:

			xt_xlate_add(xl, "ect1");

			break;

		case 2:

			xt_xlate_add(xl, "ect0");

			break;

		case 3:

			xt_xlate_add(xl, "ce");

			break;

		}

	}

	return 1;

}

static struct xtables_match ecn_mt_reg = {

	.name          = "ecn",

	.version       = XTABLES_VERSION,

	.family        = NFPROTO_UNSPEC,

	.size          = XT_ALIGN(sizeof(struct xt_ecn_info)),

	.userspacesize = XT_ALIGN(sizeof(struct xt_ecn_info)),

	.help          = ecn_help,

	.print         = ecn_print,

	.save          = ecn_save,

	.x6_parse      = ecn_parse,

	.x6_fcheck     = ecn_check,

	.x6_options    = ecn_opts,

	.xlate	       = ecn_xlate,

};

void _init(void)

{

	xtables_register_match(&ecn_mt_reg);

}