/* 

 * Shared library add-on to iptables to match 

 * packets by their type (BROADCAST, UNICAST, MULTICAST). 

 *

 * Michal Ludvig <michal@logix.cz>

 */

#include <stdio.h>

#include <string.h>

#include <xtables.h>

#include <linux/if_packet.h>

#include <linux/netfilter/xt_pkttype.h>

enum {

	O_PKTTYPE = 0,

};

struct pkttypes {

	const char *name;

	unsigned char pkttype;

	unsigned char printhelp;

	const char *help;

};

struct pkttypes_xlate {

	const char *name;

	unsigned char pkttype;

};

static const struct pkttypes supported_types[] = {

	{"unicast", PACKET_HOST, 1, "to us"},

	{"broadcast", PACKET_BROADCAST, 1, "to all"},

	{"multicast", PACKET_MULTICAST, 1, "to group"},

/*

	{"otherhost", PACKET_OTHERHOST, 1, "to someone else"},

	{"outgoing", PACKET_OUTGOING, 1, "outgoing of any type"},

*/

	/* aliases */

	{"bcast", PACKET_BROADCAST, 0, NULL},

	{"mcast", PACKET_MULTICAST, 0, NULL},

	{"host", PACKET_HOST, 0, NULL}

};

static void print_types(void)

{

	unsigned int	i;

	printf("Valid packet types:\n");

	for (i = 0; i < ARRAY_SIZE(supported_types); ++i)

		if(supported_types[i].printhelp == 1)

			printf("\t%-14s\t\t%s\n", supported_types[i].name, supported_types[i].help);

	printf("\n");

}

static void pkttype_help(void)

{

	printf(

"pkttype match options:\n"

"[!] --pkt-type packettype    match packet type\n");

	print_types();

}

static const struct xt_option_entry pkttype_opts[] = {

	{.name = "pkt-type", .id = O_PKTTYPE, .type = XTTYPE_STRING,

	 .flags = XTOPT_MAND | XTOPT_INVERT},

	XTOPT_TABLEEND,

};

static void parse_pkttype(const char *pkttype, struct xt_pkttype_info *info)

{

	unsigned int	i;

	for (i = 0; i < ARRAY_SIZE(supported_types); ++i)

		if(strcasecmp(pkttype, supported_types[i].name)==0)

		{

			info->pkttype=supported_types[i].pkttype;

			return;

		}

	xtables_error(PARAMETER_PROBLEM, "Bad packet type '%s'", pkttype);

}

static void pkttype_parse(struct xt_option_call *cb)

{

	struct xt_pkttype_info *info = cb->data;

	xtables_option_parse(cb);

	parse_pkttype(cb->arg, info);

	if (cb->invert)

		info->invert = 1;

}

static void print_pkttype(const struct xt_pkttype_info *info)

{

	unsigned int	i;

	for (i = 0; i < ARRAY_SIZE(supported_types); ++i)

		if(supported_types[i].pkttype==info->pkttype)

		{

			printf("%s", supported_types[i].name);

			return;

		}

	printf("%d", info->pkttype);	/* in case we didn't find an entry in named-packtes */

}

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

                          int numeric)

{

	const struct xt_pkttype_info *info = (const void *)match->data;

	printf(" PKTTYPE %s= ", info->invert ? "!" : "");

	print_pkttype(info);

}

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

{

	const struct xt_pkttype_info *info = (const void *)match->data;

	printf("%s --pkt-type ", info->invert ? " !" : "");

	print_pkttype(info);

}

static const struct pkttypes_xlate supported_types_xlate[] = {

	{"unicast",	PACKET_HOST},

	{"broadcast",	PACKET_BROADCAST},

	{"multicast",	PACKET_MULTICAST},

};

static void print_pkttype_xlate(const struct xt_pkttype_info *info,

				struct xt_xlate *xl)

{

	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(supported_types_xlate); ++i) {

		if (supported_types_xlate[i].pkttype == info->pkttype) {

			xt_xlate_add(xl, "%s", supported_types_xlate[i].name);

			return;

		}

	}

	xt_xlate_add(xl, "%d", info->pkttype);

}

static int pkttype_xlate(struct xt_xlate *xl,

			 const struct xt_xlate_mt_params *params)

{

	const struct xt_pkttype_info *info = (const void *)params->match->data;

	xt_xlate_add(xl, "pkttype%s ", info->invert ? " !=" : "");

	print_pkttype_xlate(info, xl);

	return 1;

}

static struct xtables_match pkttype_match = {

	.family		= NFPROTO_UNSPEC,

	.name		= "pkttype",

	.version	= XTABLES_VERSION,

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

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

	.help		= pkttype_help,

	.print		= pkttype_print,

	.save		= pkttype_save,

	.x6_parse	= pkttype_parse,

	.x6_options	= pkttype_opts,

	.xlate		= pkttype_xlate,

};

void _init(void)

{

	xtables_register_match(&pkttype_match);

}