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

 *

 * (C) 2003 by Harald Welte <laforge@gnumonks.org>

 *

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

 *

 * libipt_ecn.c borrowed heavily from libipt_dscp.c

 *

 */

#include <stdbool.h>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <getopt.h>

#include <netdb.h>

#include <ctype.h>

#include <netinet/in.h>

#include <xtables.h>

#include <linux/netfilter/xt_sctp.h>

#if 0

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

#define static

#else

#define DEBUGP(format, fist...) 

#endif

static void

print_chunk(uint32_t chunknum, int numeric);

static void sctp_init(struct xt_entry_match *m)

{

	int i;

	struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;

	for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {

		einfo->flag_info[i].chunktype = -1;

	}

}

static void sctp_help(void)

{

	printf(

"sctp 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" 

"[!] --chunk-types (all|any|none) (chunktype[:flags])+	match if all, any or none of\n"

"						        chunktypes are present\n"

"chunktypes - DATA INIT INIT_ACK SACK HEARTBEAT HEARTBEAT_ACK ABORT SHUTDOWN SHUTDOWN_ACK ERROR COOKIE_ECHO COOKIE_ACK ECN_ECNE ECN_CWR SHUTDOWN_COMPLETE ASCONF ASCONF_ACK FORWARD_TSN ALL NONE\n");

}

static const struct option sctp_opts[] = {

	{.name = "source-port",      .has_arg = true, .val = '1'},

	{.name = "sport",            .has_arg = true, .val = '1'},

	{.name = "destination-port", .has_arg = true, .val = '2'},

	{.name = "dport",            .has_arg = true, .val = '2'},

	{.name = "chunk-types",      .has_arg = true, .val = '3'},

	XT_GETOPT_TABLEEND,

};

static void

parse_sctp_ports(const char *portstring, 

		 uint16_t *ports)

{

	char *buffer;

	char *cp;

	buffer = strdup(portstring);

	DEBUGP("%s\n", portstring);

	if ((cp = strchr(buffer, ':')) == NULL) {

		ports[0] = ports[1] = xtables_parse_port(buffer, "sctp");

	}

	else {

		*cp = '\0';

		cp++;

		ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0;

		ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF;

		if (ports[0] > ports[1])

			xtables_error(PARAMETER_PROBLEM,

				   "invalid portrange (min > max)");

	}

	free(buffer);

}

struct sctp_chunk_names {

	const char *name;

	unsigned int chunk_type;

	const char *valid_flags;

};

/*'ALL' and 'NONE' will be treated specially. */

static const struct sctp_chunk_names sctp_chunk_names[]

= { { .name = "DATA", 		.chunk_type = 0,   .valid_flags = "----IUBE"},

    { .name = "INIT", 		.chunk_type = 1,   .valid_flags = "--------"},

    { .name = "INIT_ACK", 	.chunk_type = 2,   .valid_flags = "--------"},

    { .name = "SACK",		.chunk_type = 3,   .valid_flags = "--------"},

    { .name = "HEARTBEAT",	.chunk_type = 4,   .valid_flags = "--------"},

    { .name = "HEARTBEAT_ACK",	.chunk_type = 5,   .valid_flags = "--------"},

    { .name = "ABORT",		.chunk_type = 6,   .valid_flags = "-------T"},

    { .name = "SHUTDOWN",	.chunk_type = 7,   .valid_flags = "--------"},

    { .name = "SHUTDOWN_ACK",	.chunk_type = 8,   .valid_flags = "--------"},

    { .name = "ERROR",		.chunk_type = 9,   .valid_flags = "--------"},

    { .name = "COOKIE_ECHO",	.chunk_type = 10,  .valid_flags = "--------"},

    { .name = "COOKIE_ACK",	.chunk_type = 11,  .valid_flags = "--------"},

    { .name = "ECN_ECNE",	.chunk_type = 12,  .valid_flags = "--------"},

    { .name = "ECN_CWR",	.chunk_type = 13,  .valid_flags = "--------"},

    { .name = "SHUTDOWN_COMPLETE", .chunk_type = 14,  .valid_flags = "-------T"},

    { .name = "ASCONF",		.chunk_type = 193,  .valid_flags = "--------"},

    { .name = "ASCONF_ACK",	.chunk_type = 128,  .valid_flags = "--------"},

    { .name = "FORWARD_TSN",	.chunk_type = 192,  .valid_flags = "--------"},

};

static void

save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,

		     int *flag_count,

		     int chunktype, 

		     int bit, 

		     int set)

{

	int i;

	for (i = 0; i < *flag_count; i++) {

		if (flag_info[i].chunktype == chunktype) {

			DEBUGP("Previous match found\n");

			flag_info[i].chunktype = chunktype;

			flag_info[i].flag_mask |= (1 << bit);

			if (set) {

				flag_info[i].flag |= (1 << bit);

			}

			return;

		}

	}

	if (*flag_count == XT_NUM_SCTP_FLAGS) {

		xtables_error (PARAMETER_PROBLEM,

			"Number of chunk types with flags exceeds currently allowed limit."

			"Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"

			"recompiling both the kernel space and user space modules\n");

	}

	flag_info[*flag_count].chunktype = chunktype;

	flag_info[*flag_count].flag_mask |= (1 << bit);

	if (set) {

		flag_info[*flag_count].flag |= (1 << bit);

	}

	(*flag_count)++;

}

static void

parse_sctp_chunk(struct xt_sctp_info *einfo, 

		 const char *chunks)

{

	char *ptr;

	char *buffer;

	unsigned int i, j;

	int found = 0;

	char *chunk_flags;

	buffer = strdup(chunks);

	DEBUGP("Buffer: %s\n", buffer);

	SCTP_CHUNKMAP_RESET(einfo->chunkmap);

	if (!strcasecmp(buffer, "ALL")) {

		SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);

		goto out;

	}

	if (!strcasecmp(buffer, "NONE")) {

		SCTP_CHUNKMAP_RESET(einfo->chunkmap);

		goto out;

	}

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

		found = 0;

		DEBUGP("Next Chunk type %s\n", ptr);

		if ((chunk_flags = strchr(ptr, ':')) != NULL) {

			*chunk_flags++ = 0;

		}

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

			if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {

				DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);

				SCTP_CHUNKMAP_SET(einfo->chunkmap, 

					sctp_chunk_names[i].chunk_type);

				found = 1;

				break;

			}

		if (!found)

			xtables_error(PARAMETER_PROBLEM,

				   "Unknown sctp chunk `%s'", ptr);

		if (chunk_flags) {

			DEBUGP("Chunk flags %s\n", chunk_flags);

			for (j = 0; j < strlen(chunk_flags); j++) {

				char *p;

				int bit;

				if ((p = strchr(sctp_chunk_names[i].valid_flags, 

						toupper(chunk_flags[j]))) != NULL) {

					bit = p - sctp_chunk_names[i].valid_flags;

					bit = 7 - bit;

					save_chunk_flag_info(einfo->flag_info, 

						&(einfo->flag_count), i, bit, 

						isupper(chunk_flags[j]));

				} else {

					xtables_error(PARAMETER_PROBLEM,

						"Invalid flags for chunk type %d\n", i);

				}

			}

		}

	}

out:

	free(buffer);

}

static void

parse_sctp_chunks(struct xt_sctp_info *einfo,

		  const char *match_type,

		  const char *chunks)

{

	DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);

	if (!strcasecmp(match_type, "ANY")) {

		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;

	} else 	if (!strcasecmp(match_type, "ALL")) {

		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;

	} else 	if (!strcasecmp(match_type, "ONLY")) {

		einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;

	} else {

		xtables_error (PARAMETER_PROBLEM,

			"Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");

	}

	SCTP_CHUNKMAP_RESET(einfo->chunkmap);

	parse_sctp_chunk(einfo, chunks);

}

static int

sctp_parse(int c, char **argv, int invert, unsigned int *flags,

           const void *entry, struct xt_entry_match **match)

{

	struct xt_sctp_info *einfo

		= (struct xt_sctp_info *)(*match)->data;

	switch (c) {

	case '1':

		if (*flags & XT_SCTP_SRC_PORTS)

			xtables_error(PARAMETER_PROBLEM,

			           "Only one `--source-port' allowed");

		einfo->flags |= XT_SCTP_SRC_PORTS;

		parse_sctp_ports(optarg, einfo->spts);

		if (invert)

			einfo->invflags |= XT_SCTP_SRC_PORTS;

		*flags |= XT_SCTP_SRC_PORTS;

		break;

	case '2':

		if (*flags & XT_SCTP_DEST_PORTS)

			xtables_error(PARAMETER_PROBLEM,

				   "Only one `--destination-port' allowed");

		einfo->flags |= XT_SCTP_DEST_PORTS;

		parse_sctp_ports(optarg, einfo->dpts);

		if (invert)

			einfo->invflags |= XT_SCTP_DEST_PORTS;

		*flags |= XT_SCTP_DEST_PORTS;

		break;

	case '3':

		if (*flags & XT_SCTP_CHUNK_TYPES)

			xtables_error(PARAMETER_PROBLEM,

				   "Only one `--chunk-types' allowed");

		if (!argv[optind] 

		    || argv[optind][0] == '-' || argv[optind][0] == '!')

			xtables_error(PARAMETER_PROBLEM,

				   "--chunk-types requires two args");

		einfo->flags |= XT_SCTP_CHUNK_TYPES;

		parse_sctp_chunks(einfo, optarg, argv[optind]);

		if (invert)

			einfo->invflags |= XT_SCTP_CHUNK_TYPES;

		optind++;

		*flags |= XT_SCTP_CHUNK_TYPES;

		break;

	}

	return 1;

}

static const char *

port_to_service(int port)

{

	const struct servent *service;

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

		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_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask)

{

	int i;

	DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags, 

			chunk_flags_mask);

	if (chunk_flags_mask) {

		printf(":");

	}

	for (i = 7; i >= 0; i--) {

		if (chunk_flags_mask & (1 << i)) {

			if (chunk_flags & (1 << i)) {

				printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);

			} else {

				printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));

			}

		}

	}

}

static void

print_chunk(uint32_t chunknum, int numeric)

{

	if (numeric) {

		printf("0x%04X", chunknum);

	}

	else {

		int i;

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

			if (sctp_chunk_names[i].chunk_type == chunknum)

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

	}

}

static void

print_chunks(const struct xt_sctp_info *einfo, int numeric)

{

	uint32_t chunk_match_type = einfo->chunk_match_type;

	const struct xt_sctp_flag_info *flag_info = einfo->flag_info;

	int flag_count = einfo->flag_count;

	int i, j;

	int flag;

	switch (chunk_match_type) {

		case SCTP_CHUNK_MATCH_ANY:	printf(" any"); break;

		case SCTP_CHUNK_MATCH_ALL:	printf(" all"); break;

		case SCTP_CHUNK_MATCH_ONLY:	printf(" only"); break;

		default:	printf("Never reach here\n"); break;

	}

	if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {

		printf(" NONE");

		goto out;

	}

	if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {

		printf(" ALL");

		goto out;

	}

	flag = 0;

	for (i = 0; i < 256; i++) {

		if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {

			if (flag)

				printf(",");

			else

				putchar(' ');

			flag = 1;

			print_chunk(i, numeric);

			for (j = 0; j < flag_count; j++) {

				if (flag_info[j].chunktype == i) {

					print_chunk_flags(i, flag_info[j].flag,

						flag_info[j].flag_mask);

				}

			}

		}

	}

out:

	return;

}

static void

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

{

	const struct xt_sctp_info *einfo =

		(const struct xt_sctp_info *)match->data;

	printf(" sctp");

	if (einfo->flags & XT_SCTP_SRC_PORTS) {

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

			einfo->invflags & XT_SCTP_SRC_PORTS,

			numeric);

	}

	if (einfo->flags & XT_SCTP_DEST_PORTS) {

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

			einfo->invflags & XT_SCTP_DEST_PORTS,

			numeric);

	}

	if (einfo->flags & XT_SCTP_CHUNK_TYPES) {

		/* FIXME: print_chunks() is used in save() where the printing of '!'

		s taken care of, so we need to do that here as well */

		if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {

			printf(" !");

		}

		print_chunks(einfo, numeric);

	}

}

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

{

	const struct xt_sctp_info *einfo =

		(const struct xt_sctp_info *)match->data;

	if (einfo->flags & XT_SCTP_SRC_PORTS) {

		if (einfo->invflags & XT_SCTP_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_SCTP_DEST_PORTS) {

		if (einfo->invflags & XT_SCTP_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_SCTP_CHUNK_TYPES) {

		if (einfo->invflags & XT_SCTP_CHUNK_TYPES)

			printf(" !");

		printf(" --chunk-types");

		print_chunks(einfo, 0);

	}

}

static int sctp_xlate(struct xt_xlate *xl,

		      const struct xt_xlate_mt_params *params)

{

	const struct xt_sctp_info *einfo =

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

	char *space = "";

	if (!einfo->flags)

		return 0;

	xt_xlate_add(xl, "sctp ");

	if (einfo->flags & XT_SCTP_SRC_PORTS) {

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

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

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

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

		else

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

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

				     einfo->spts[0]);

		space = " ";

	}

	if (einfo->flags & XT_SCTP_DEST_PORTS) {

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

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

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

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

		else

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

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

				     einfo->dpts[0]);

	}

	return 1;

}

static struct xtables_match sctp_match = {

	.name		= "sctp",

	.family		= NFPROTO_UNSPEC,

	.version	= XTABLES_VERSION,

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

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

	.help		= sctp_help,

	.init		= sctp_init,

	.parse		= sctp_parse,

	.print		= sctp_print,

	.save		= sctp_save,

	.extra_opts	= sctp_opts,

	.xlate		= sctp_xlate,

};

void _init(void)

{

	xtables_register_match(&sctp_match);

}