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

 *

 * (C) 2005 by Harald Welte <laforge@netfilter.org>

 *

 * This program is distributed under the terms of GNU GPL v2, 1991

 *

 */

#include <stdint.h>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <netdb.h>

#include <arpa/inet.h>

#include <xtables.h>

#include <linux/dccp.h>

#include <linux/netfilter/x_tables.h>

#include <linux/netfilter/xt_dccp.h>

#if 0

#define DEBUGP(format, first...) printf(format, ##first)

#define static

#else

#define DEBUGP(format, fist...) 

#endif

enum {

	O_SOURCE_PORT = 0,

	O_DEST_PORT,

	O_DCCP_TYPES,

	O_DCCP_OPTION,

};

static void dccp_help(void)

{

	printf(

"dccp match options\n"

"[!] --source-port port[:port]                          match source port(s)\n"

" --sport ...\n"

"[!] --destination-port port[:port]                     match destination port(s)\n"

" --dport ...\n"

"[!] --dccp-types type[,...]                            match when packet is one of the given types\n"

"[!] --dccp-option option                               match if option (by number!) is set\n"

);

}

#define s struct xt_dccp_info

static const struct xt_option_entry dccp_opts[] = {

	{.name = "source-port", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},

	{.name = "sport", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},

	{.name = "destination-port", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},

	{.name = "dport", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,

	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},

	{.name = "dccp-types", .id = O_DCCP_TYPES, .type = XTTYPE_STRING,

	 .flags = XTOPT_INVERT},

	{.name = "dccp-option", .id = O_DCCP_OPTION, .type = XTTYPE_UINT8,

	 .min = 1, .max = UINT8_MAX, .flags = XTOPT_INVERT | XTOPT_PUT,

	 XTOPT_POINTER(s, option)},

	XTOPT_TABLEEND,

};

#undef s

static const char *const dccp_pkt_types[] = {

	[DCCP_PKT_REQUEST] 	= "REQUEST",

	[DCCP_PKT_RESPONSE]	= "RESPONSE",

	[DCCP_PKT_DATA]		= "DATA",

	[DCCP_PKT_ACK]		= "ACK",

	[DCCP_PKT_DATAACK]	= "DATAACK",

	[DCCP_PKT_CLOSEREQ]	= "CLOSEREQ",

	[DCCP_PKT_CLOSE]	= "CLOSE",

	[DCCP_PKT_RESET]	= "RESET",

	[DCCP_PKT_SYNC]		= "SYNC",

	[DCCP_PKT_SYNCACK]	= "SYNCACK",

	[DCCP_PKT_INVALID]	= "INVALID",

};

static uint16_t

parse_dccp_types(const char *typestring)

{

	uint16_t typemask = 0;

	char *ptr, *buffer;

	buffer = strdup(typestring);

	for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {

		unsigned int i;

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

			if (!strcasecmp(dccp_pkt_types[i], ptr)) {

				typemask |= (1 << i);

				break;

			}

		if (i == ARRAY_SIZE(dccp_pkt_types))

			xtables_error(PARAMETER_PROBLEM,

				   "Unknown DCCP type `%s'", ptr);

	}

	free(buffer);

	return typemask;

}

static void dccp_parse(struct xt_option_call *cb)

{

	struct xt_dccp_info *einfo = cb->data;

	xtables_option_parse(cb);

	switch (cb->entry->id) {

	case O_SOURCE_PORT:

		einfo->flags |= XT_DCCP_SRC_PORTS;

		if (cb->invert)

			einfo->invflags |= XT_DCCP_SRC_PORTS;

		break;

	case O_DEST_PORT:

		einfo->flags |= XT_DCCP_DEST_PORTS;

		if (cb->invert)

			einfo->invflags |= XT_DCCP_DEST_PORTS;

		break;

	case O_DCCP_TYPES:

		einfo->flags |= XT_DCCP_TYPE;

		einfo->typemask = parse_dccp_types(cb->arg);

		if (cb->invert)

			einfo->invflags |= XT_DCCP_TYPE;

		break;

	case O_DCCP_OPTION:

		einfo->flags |= XT_DCCP_OPTION;

		if (cb->invert)

			einfo->invflags |= XT_DCCP_OPTION;

		break;

	}

}

static const char *

port_to_service(int port)

{

	const struct servent *service;

	if ((service = getservbyport(htons(port), "dccp")))

		return service->s_name;

	return NULL;

}

static void

print_port(uint16_t port, int numeric)

{

	const char *service;

	if (numeric || (service = port_to_service(port)) == NULL)

		printf("%u", port);

	else

		printf("%s", service);

}

static void

print_ports(const char *name, uint16_t min, uint16_t max,

	    int invert, int numeric)

{

	const char *inv = invert ? "!" : "";

	if (min != 0 || max != 0xFFFF || invert) {

		printf(" %s", name);

		if (min == max) {

			printf(":%s", inv);

			print_port(min, numeric);

		} else {

			printf("s:%s", inv);

			print_port(min, numeric);

			printf(":");

			print_port(max, numeric);

		}

	}

}

static void

print_types(uint16_t types, int inverted, int numeric)

{

	int have_type = 0;

	if (inverted)

		printf(" !");

	printf(" ");

	while (types) {

		unsigned int i;

		for (i = 0; !(types & (1 << i)); i++);

		if (have_type)

			printf(",");

		else

			have_type = 1;

		if (numeric)

			printf("%u", i);

		else

			printf("%s", dccp_pkt_types[i]);

		types &= ~(1 << i);

	}

}

static void

print_option(uint8_t option, int invert, int numeric)

{

	if (option || invert)

		printf(" option=%s%u", invert ? "!" : "", option);

}

static void

dccp_print(const void *ip, const struct xt_entry_match *match, int numeric)

{

	const struct xt_dccp_info *einfo =

		(const struct xt_dccp_info *)match->data;

	printf(" dccp");

	if (einfo->flags & XT_DCCP_SRC_PORTS) {

		print_ports("spt", einfo->spts[0], einfo->spts[1],

			einfo->invflags & XT_DCCP_SRC_PORTS,

			numeric);

	}

	if (einfo->flags & XT_DCCP_DEST_PORTS) {

		print_ports("dpt", einfo->dpts[0], einfo->dpts[1],

			einfo->invflags & XT_DCCP_DEST_PORTS,

			numeric);

	}

	if (einfo->flags & XT_DCCP_TYPE) {

		print_types(einfo->typemask,

			   einfo->invflags & XT_DCCP_TYPE,

			   numeric);

	}

	if (einfo->flags & XT_DCCP_OPTION) {

		print_option(einfo->option,

			     einfo->invflags & XT_DCCP_OPTION, numeric);

	}

}

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

{

	const struct xt_dccp_info *einfo =

		(const struct xt_dccp_info *)match->data;

	if (einfo->flags & XT_DCCP_SRC_PORTS) {

		if (einfo->invflags & XT_DCCP_SRC_PORTS)

			printf(" !");

		if (einfo->spts[0] != einfo->spts[1])

			printf(" --sport %u:%u",

			       einfo->spts[0], einfo->spts[1]);

		else

			printf(" --sport %u", einfo->spts[0]);

	}

	if (einfo->flags & XT_DCCP_DEST_PORTS) {

		if (einfo->invflags & XT_DCCP_DEST_PORTS)

			printf(" !");

		if (einfo->dpts[0] != einfo->dpts[1])

			printf(" --dport %u:%u",

			       einfo->dpts[0], einfo->dpts[1]);

		else

			printf(" --dport %u", einfo->dpts[0]);

	}

	if (einfo->flags & XT_DCCP_TYPE) {

		printf("%s --dccp-types",

		       einfo->invflags & XT_DCCP_TYPE ? " !" : "");

		print_types(einfo->typemask, false, 0);

	}

	if (einfo->flags & XT_DCCP_OPTION) {

		printf("%s --dccp-option %u",

			einfo->invflags & XT_DCCP_OPTION ? " !" : "",

			einfo->option);

	}

}

static const char *const dccp_pkt_types_xlate[] = {

	[DCCP_PKT_REQUEST]      = "request",

	[DCCP_PKT_RESPONSE]     = "response",

	[DCCP_PKT_DATA]         = "data",

	[DCCP_PKT_ACK]          = "ack",

	[DCCP_PKT_DATAACK]      = "dataack",

	[DCCP_PKT_CLOSEREQ]     = "closereq",

	[DCCP_PKT_CLOSE]        = "close",

	[DCCP_PKT_RESET]        = "reset",

	[DCCP_PKT_SYNC]         = "sync",

	[DCCP_PKT_SYNCACK]      = "syncack",

};

static int dccp_type_xlate(const struct xt_dccp_info *einfo,

			   struct xt_xlate *xl)

{

	bool have_type = false, set_need = false;

	uint16_t types = einfo->typemask;

	if (types & (1 << DCCP_PKT_INVALID))

		return 0;

	xt_xlate_add(xl, " dccp type%s ", einfo->invflags ? " !=" : "");

	if ((types != 0) && !(types == (types & -types))) {

		xt_xlate_add(xl, "{");

		set_need = true;

	}

	while (types) {

		unsigned int i;

		for (i = 0; !(types & (1 << i)); i++);

		if (have_type)

			xt_xlate_add(xl, ", ");

		else

			have_type = true;

		xt_xlate_add(xl, "%s", dccp_pkt_types_xlate[i]);

		types &= ~(1 << i);

	}

	if (set_need)

		xt_xlate_add(xl, "}");

	return 1;

}

static int dccp_xlate(struct xt_xlate *xl,

		      const struct xt_xlate_mt_params *params)

{

	const struct xt_dccp_info *einfo =

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

	char *space = "";

	int ret = 1;

	xt_xlate_add(xl, "dccp ");

	if (einfo->flags & XT_DCCP_SRC_PORTS) {

		if (einfo->spts[0] != einfo->spts[1])

			xt_xlate_add(xl, "sport%s %u-%u",

				     einfo->invflags & XT_DCCP_SRC_PORTS ? " !=" : "",

				     einfo->spts[0], einfo->spts[1]);

		else

			xt_xlate_add(xl, "sport%s %u",

				     einfo->invflags & XT_DCCP_SRC_PORTS ? " !=" : "",

				     einfo->spts[0]);

		space = " ";

	}

	if (einfo->flags & XT_DCCP_DEST_PORTS) {

		if (einfo->dpts[0] != einfo->dpts[1])

			xt_xlate_add(xl, "%sdport%s %u-%u", space,

				     einfo->invflags & XT_DCCP_DEST_PORTS ? " !=" : "",

				     einfo->dpts[0], einfo->dpts[1]);

		else

			xt_xlate_add(xl, "%sdport%s %u", space,

				     einfo->invflags & XT_DCCP_DEST_PORTS ? " !=" : "",

				     einfo->dpts[0]);

	}

	if (einfo->flags & XT_DCCP_TYPE)

		ret = dccp_type_xlate(einfo, xl);

	if (einfo->flags & XT_DCCP_OPTION)

		ret = 0;

	return ret;

}

static struct xtables_match dccp_match = {

	.name		= "dccp",

	.family		= NFPROTO_UNSPEC,

	.version	= XTABLES_VERSION,

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

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

	.help		= dccp_help,

	.print		= dccp_print,

	.save		= dccp_save,

	.x6_parse	= dccp_parse,

	.x6_options	= dccp_opts,

	.xlate		= dccp_xlate,

};

void _init(void)

{

	xtables_register_match(&dccp_match);

}