/* Shared library add-on to iptables for the TTL target

 * (C) 2000 by Harald Welte <laforge@gnumonks.org>

 *

 * This program is distributed under the terms of GNU GPL

 */

#include <stdio.h>

#include <xtables.h>

#include <linux/netfilter_ipv4/ipt_TTL.h>

enum {

	O_TTL_SET = 0,

	O_TTL_INC,

	O_TTL_DEC,

	F_TTL_SET = 1 << O_TTL_SET,

	F_TTL_INC = 1 << O_TTL_INC,

	F_TTL_DEC = 1 << O_TTL_DEC,

	F_ANY     = F_TTL_SET | F_TTL_INC | F_TTL_DEC,

};

#define s struct ipt_TTL_info

static const struct xt_option_entry TTL_opts[] = {

	{.name = "ttl-set", .type = XTTYPE_UINT8, .id = O_TTL_SET,

	 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl)},

	{.name = "ttl-dec", .type = XTTYPE_UINT8, .id = O_TTL_DEC,

	 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),

	 .min = 1},

	{.name = "ttl-inc", .type = XTTYPE_UINT8, .id = O_TTL_INC,

	 .excl = F_ANY, .flags = XTOPT_PUT, XTOPT_POINTER(s, ttl),

	 .min = 1},

	XTOPT_TABLEEND,

};

#undef s

static void TTL_help(void)

{

	printf(

"TTL target options\n"

"  --ttl-set value		Set TTL to <value 0-255>\n"

"  --ttl-dec value		Decrement TTL by <value 1-255>\n"

"  --ttl-inc value		Increment TTL by <value 1-255>\n");

}

static void TTL_parse(struct xt_option_call *cb)

{

	struct ipt_TTL_info *info = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_TTL_SET:

		info->mode = IPT_TTL_SET;

		break;

	case O_TTL_DEC:

		info->mode = IPT_TTL_DEC;

		break;

	case O_TTL_INC:

		info->mode = IPT_TTL_INC;

		break;

	}

}

static void TTL_check(struct xt_fcheck_call *cb)

{

	if (!(cb->xflags & F_ANY))

		xtables_error(PARAMETER_PROBLEM,

				"TTL: You must specify an action");

}

static void TTL_save(const void *ip, const struct xt_entry_target *target)

{

	const struct ipt_TTL_info *info = 

		(struct ipt_TTL_info *) target->data;

	switch (info->mode) {

		case IPT_TTL_SET:

			printf(" --ttl-set");

			break;

		case IPT_TTL_DEC:

			printf(" --ttl-dec");

			break;

		case IPT_TTL_INC:

			printf(" --ttl-inc");

			break;

	}

	printf(" %u", info->ttl);

}

static void TTL_print(const void *ip, const struct xt_entry_target *target,

                      int numeric)

{

	const struct ipt_TTL_info *info =

		(struct ipt_TTL_info *) target->data;

	printf(" TTL ");

	switch (info->mode) {

		case IPT_TTL_SET:

			printf("set to");

			break;

		case IPT_TTL_DEC:

			printf("decrement by");

			break;

		case IPT_TTL_INC:

			printf("increment by");

			break;

	}

	printf(" %u", info->ttl);

}

static struct xtables_target ttl_tg_reg = {

	.name		= "TTL",

	.version	= XTABLES_VERSION,

	.family		= NFPROTO_IPV4,

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

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

	.help		= TTL_help,

	.print		= TTL_print,

	.save		= TTL_save,

	.x6_parse	= TTL_parse,

	.x6_fcheck	= TTL_check,

	.x6_options	= TTL_opts,

};

void _init(void)

{

	xtables_register_target(&ttl_tg_reg);

}