/* ebt_nat

 *

 * Authors:

 * Bart De Schuymer <bdschuym@pandora.be>

 *

 * June, 2002

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <getopt.h>

#include <netinet/ether.h>

#include <xtables.h>

#include <linux/netfilter_bridge/ebt_nat.h>

#include "iptables/nft.h"

#include "iptables/nft-bridge.h"

#define NAT_S '1'

#define NAT_S_TARGET '2'

#define NAT_S_ARP '3'

static const struct option brsnat_opts[] =

{

	{ "to-source"     , required_argument, 0, NAT_S },

	{ "to-src"        , required_argument, 0, NAT_S },

	{ "snat-target"   , required_argument, 0, NAT_S_TARGET },

	{ "snat-arp"      ,       no_argument, 0, NAT_S_ARP },

	{ 0 }

};

static void brsnat_print_help(void)

{

	printf(

	"snat options:\n"

	" --to-src address       : MAC address to map source to\n"

	" --snat-target target   : ACCEPT, DROP, RETURN or CONTINUE\n"

	" --snat-arp             : also change src address in arp msg\n");

}

static void brsnat_init(struct xt_entry_target *target)

{

	struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;

	natinfo->target = EBT_ACCEPT;

}

#define OPT_SNAT         0x01

#define OPT_SNAT_TARGET  0x02

#define OPT_SNAT_ARP     0x04

static int brsnat_parse(int c, char **argv, int invert, unsigned int *flags,

			 const void *entry, struct xt_entry_target **target)

{

	struct ebt_nat_info *natinfo = (struct ebt_nat_info *)(*target)->data;

	struct ether_addr *addr;

	switch (c) {

	case NAT_S:

		EBT_CHECK_OPTION(flags, OPT_SNAT);

		if (!(addr = ether_aton(optarg)))

			xtables_error(PARAMETER_PROBLEM, "Problem with specified --to-source mac");

		memcpy(natinfo->mac, addr, ETH_ALEN);

		break;

	case NAT_S_TARGET:

		{ unsigned int tmp;

		EBT_CHECK_OPTION(flags, OPT_SNAT_TARGET);

		if (ebt_fill_target(optarg, &tmp))

			xtables_error(PARAMETER_PROBLEM, "Illegal --snat-target target");

		natinfo->target = (natinfo->target & ~EBT_VERDICT_BITS) | (tmp & EBT_VERDICT_BITS);

		}

		break;

	case NAT_S_ARP:

		EBT_CHECK_OPTION(flags, OPT_SNAT_ARP);

		natinfo->target ^= NAT_ARP_BIT;

		break;

	default:

		return 0;

	}

	return 1;

}

static void brsnat_final_check(unsigned int flags)

{

	if (!flags)

		xtables_error(PARAMETER_PROBLEM,

			      "You must specify proper arguments");

}

static void brsnat_print(const void *ip, const struct xt_entry_target *target, int numeric)

{

	struct ebt_nat_info *natinfo = (struct ebt_nat_info *)target->data;

	printf("--to-src ");

	xtables_print_mac(natinfo->mac);

	if (!(natinfo->target&NAT_ARP_BIT))

		printf(" --snat-arp");

	printf(" --snat-target %s", ebt_target_name((natinfo->target|~EBT_VERDICT_BITS)));

}

static const char* brsnat_verdict(int verdict)

{

	switch (verdict) {

	case EBT_ACCEPT: return "accept";

	case EBT_DROP: return "drop";

	case EBT_CONTINUE: return "continue";

	case EBT_RETURN: return "return";

	}

	return "";

}

static int brsnat_xlate(struct xt_xlate *xl,

			 const struct xt_xlate_tg_params *params)

{

	const struct ebt_nat_info *natinfo = (const void*)params->target->data;

	xt_xlate_add(xl, "ether saddr set %s ",

		     ether_ntoa((struct ether_addr *)natinfo->mac));

	/* NAT_ARP_BIT set -> no arp mangling, not set -> arp mangling (yes, its inverted) */

	if (!(natinfo->target&NAT_ARP_BIT))

		return 0;

	xt_xlate_add(xl, "%s ", brsnat_verdict(natinfo->target | ~EBT_VERDICT_BITS));

	return 1;

}

static struct xtables_target brsnat_target =

{

	.name		= "snat",

	.version	= XTABLES_VERSION,

	.family		= NFPROTO_BRIDGE,

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

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

	.help		= brsnat_print_help,

	.init		= brsnat_init,

	.parse		= brsnat_parse,

	.final_check	= brsnat_final_check,

	.print		= brsnat_print,

	.xlate		= brsnat_xlate,

	.extra_opts	= brsnat_opts,

};

void _init(void)

{

	xtables_register_target(&brsnat_target);

}