extensions/ebt_ip.c

/* ebt_ip
 * 
 * Authors:
 * Bart De Schuymer <bdschuym@pandora.be>
 *
 * Changes:
 *    added ip-sport and ip-dport; parsing of port arguments is
 *    based on code from iptables-1.2.7a
 *    Innominate Security Technologies AG <mhopf@innominate.com>
 *    September, 2002
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <netdb.h>
#include "../include/ebtables_u.h"
#include <linux/netfilter_bridge/ebt_ip.h>

#define IP_SOURCE '1'
#define IP_DEST   '2'
#define IP_myTOS  '3' /* include/bits/in.h seems to already define IP_TOS */
#define IP_PROTO  '4'
#define IP_SPORT  '5'
#define IP_DPORT  '6'
#define IP_ICMP   '7'
#define IP_IGMP   '8'

static const struct option opts[] =
{
	{ "ip-source"           , required_argument, 0, IP_SOURCE },
	{ "ip-src"              , required_argument, 0, IP_SOURCE },
	{ "ip-destination"      , required_argument, 0, IP_DEST   },
	{ "ip-dst"              , required_argument, 0, IP_DEST   },
	{ "ip-tos"              , required_argument, 0, IP_myTOS  },
	{ "ip-protocol"         , required_argument, 0, IP_PROTO  },
	{ "ip-proto"            , required_argument, 0, IP_PROTO  },
	{ "ip-source-port"      , required_argument, 0, IP_SPORT  },
	{ "ip-sport"            , required_argument, 0, IP_SPORT  },
	{ "ip-destination-port" , required_argument, 0, IP_DPORT  },
	{ "ip-dport"            , required_argument, 0, IP_DPORT  },
	{ "ip-icmp-type"        , required_argument, 0, IP_ICMP   },
	{ "ip-igmp-type"        , required_argument, 0, IP_IGMP   },
	{ 0 }
};

static const struct ebt_icmp_names icmp_codes[] = {
	{ "echo-reply", 0, 0, 0xFF },
	/* Alias */ { "pong", 0, 0, 0xFF },

	{ "destination-unreachable", 3, 0, 0xFF },
	{   "network-unreachable", 3, 0, 0 },
	{   "host-unreachable", 3, 1, 1 },
	{   "protocol-unreachable", 3, 2, 2 },
	{   "port-unreachable", 3, 3, 3 },
	{   "fragmentation-needed", 3, 4, 4 },
	{   "source-route-failed", 3, 5, 5 },
	{   "network-unknown", 3, 6, 6 },
	{   "host-unknown", 3, 7, 7 },
	{   "network-prohibited", 3, 9, 9 },
	{   "host-prohibited", 3, 10, 10 },
	{   "TOS-network-unreachable", 3, 11, 11 },
	{   "TOS-host-unreachable", 3, 12, 12 },
	{   "communication-prohibited", 3, 13, 13 },
	{   "host-precedence-violation", 3, 14, 14 },
	{   "precedence-cutoff", 3, 15, 15 },

	{ "source-quench", 4, 0, 0xFF },

	{ "redirect", 5, 0, 0xFF },
	{   "network-redirect", 5, 0, 0 },
	{   "host-redirect", 5, 1, 1 },
	{   "TOS-network-redirect", 5, 2, 2 },
	{   "TOS-host-redirect", 5, 3, 3 },

	{ "echo-request", 8, 0, 0xFF },
	/* Alias */ { "ping", 8, 0, 0xFF },

	{ "router-advertisement", 9, 0, 0xFF },

	{ "router-solicitation", 10, 0, 0xFF },

	{ "time-exceeded", 11, 0, 0xFF },
	/* Alias */ { "ttl-exceeded", 11, 0, 0xFF },
	{   "ttl-zero-during-transit", 11, 0, 0 },
	{   "ttl-zero-during-reassembly", 11, 1, 1 },

	{ "parameter-problem", 12, 0, 0xFF },
	{   "ip-header-bad", 12, 0, 0 },
	{   "required-option-missing", 12, 1, 1 },

	{ "timestamp-request", 13, 0, 0xFF },

	{ "timestamp-reply", 14, 0, 0xFF },

	{ "address-mask-request", 17, 0, 0xFF },

	{ "address-mask-reply", 18, 0, 0xFF }
};

static const struct ebt_icmp_names igmp_types[] = {
	{ "membership-query", 0x11 },
	{ "membership-report-v1", 0x12 },
	{ "membership-report-v2", 0x16 },
	{ "leave-group", 0x17 },
	{ "membership-report-v3", 0x22 },
};

/* put the mask into 4 bytes */
/* transform a protocol and service name into a port number */
static uint16_t parse_port(const char *protocol, const char *name)
{
	struct servent *service;
	char *end;
	int port;

	port = strtol(name, &end, 10);
	if (*end != '\0') {
		if (protocol && 
		    (service = getservbyname(name, protocol)) != NULL)
			return ntohs(service->s_port);
	}
	else if (port >= 0 || port <= 0xFFFF) {
		return port;
	}
	ebt_print_error("Problem with specified %s port '%s'", 
			protocol?protocol:"", name);
	return 0;
}

static void
parse_port_range(const char *protocol, const char *portstring, uint16_t *ports)
{
	char *buffer;
	char *cp;
	
	buffer = strdup(portstring);
	if ((cp = strchr(buffer, ':')) == NULL)
		ports[0] = ports[1] = parse_port(protocol, buffer);
	else {
		*cp = '\0';
		cp++;
		ports[0] = buffer[0] ? parse_port(protocol, buffer) : 0;
		if (ebt_errormsg[0] != '\0')
			return;
		ports[1] = cp[0] ? parse_port(protocol, cp) : 0xFFFF;
		if (ebt_errormsg[0] != '\0')
			return;
		
		if (ports[0] > ports[1])
			ebt_print_error("Invalid portrange (min > max)");
	}
	free(buffer);
}

static void print_port_range(uint16_t *ports)
{
	if (ports[0] == ports[1])
		printf("%d ", ports[0]);
	else
		printf("%d:%d ", ports[0], ports[1]);
}

static void print_help()
{
	printf(
"ip options:\n"
"--ip-src    [!] address[/mask]: ip source specification\n"
"--ip-dst    [!] address[/mask]: ip destination specification\n"
"--ip-tos    [!] tos           : ip tos specification\n"
"--ip-proto  [!] protocol      : ip protocol specification\n"
"--ip-sport  [!] port[:port]   : tcp/udp source port or port range\n"
"--ip-dport  [!] port[:port]   : tcp/udp destination port or port range\n"
"--ip-icmp-type [!] type[[:type]/code[:code]] : icmp type/code or type/code range\n"
"--ip-igmp-type [!] type[:type]               : igmp type or type range\n");

	printf("\nValid ICMP Types:\n");
	ebt_print_icmp_types(icmp_codes, ARRAY_SIZE(icmp_codes));
	printf("\nValid IGMP Types:\n");
	ebt_print_icmp_types(igmp_types, ARRAY_SIZE(igmp_types));
}

static void init(struct ebt_entry_match *match)
{
	struct ebt_ip_info *ipinfo = (struct ebt_ip_info *)match->data;

	ipinfo->invflags = 0;
	ipinfo->bitmask = 0;
}

#define OPT_SOURCE 0x01
#define OPT_DEST   0x02
#define OPT_TOS    0x04
#define OPT_PROTO  0x08
#define OPT_SPORT  0x10
#define OPT_DPORT  0x20
#define OPT_ICMP   0x40
#define OPT_IGMP   0x80
static int parse(int c, char **argv, int argc, const struct ebt_u_entry *entry,
   unsigned int *flags, struct ebt_entry_match **match)
{
	struct ebt_ip_info *ipinfo = (struct ebt_ip_info *)(*match)->data;
	char *end;
	long int i;

	switch (c) {
	case IP_SOURCE:
		ebt_check_option2(flags, OPT_SOURCE);
		ipinfo->bitmask |= EBT_IP_SOURCE;

	case IP_DEST:
		if (c == IP_DEST) {
			ebt_check_option2(flags, OPT_DEST);
			ipinfo->bitmask |= EBT_IP_DEST;
		}
		if (ebt_check_inverse2(optarg)) {
			if (c == IP_SOURCE)
				ipinfo->invflags |= EBT_IP_SOURCE;
			else
				ipinfo->invflags |= EBT_IP_DEST;
		}
		if (c == IP_SOURCE)
			ebt_parse_ip_address(optarg, &ipinfo->saddr, &ipinfo->smsk);
		else
			ebt_parse_ip_address(optarg, &ipinfo->daddr, &ipinfo->dmsk);
		break;

	case IP_SPORT:
	case IP_DPORT:
		if (c == IP_SPORT) {
			ebt_check_option2(flags, OPT_SPORT);
			ipinfo->bitmask |= EBT_IP_SPORT;
			if (ebt_check_inverse2(optarg))
				ipinfo->invflags |= EBT_IP_SPORT;
		} else {
			ebt_check_option2(flags, OPT_DPORT);
			ipinfo->bitmask |= EBT_IP_DPORT;
			if (ebt_check_inverse2(optarg))
				ipinfo->invflags |= EBT_IP_DPORT;
		}
		if (c == IP_SPORT)
			parse_port_range(NULL, optarg, ipinfo->sport);
		else
			parse_port_range(NULL, optarg, ipinfo->dport);
		break;

	case IP_ICMP:
		ebt_check_option2(flags, OPT_ICMP);
		ipinfo->bitmask |= EBT_IP_ICMP;
		if (ebt_check_inverse2(optarg))
			ipinfo->invflags |= EBT_IP_ICMP;
		if (ebt_parse_icmp(icmp_codes, ARRAY_SIZE(icmp_codes), optarg,
				   ipinfo->icmp_type, ipinfo->icmp_code))
			return 0;
		break;

	case IP_IGMP:
		ebt_check_option2(flags, OPT_IGMP);
		ipinfo->bitmask |= EBT_IP_IGMP;
		if (ebt_check_inverse2(optarg))
			ipinfo->invflags |= EBT_IP_IGMP;
		if (ebt_parse_icmp(igmp_types, ARRAY_SIZE(igmp_types), optarg,
				   ipinfo->igmp_type, NULL))
			return 0;
		break;

	case IP_myTOS:
		ebt_check_option2(flags, OPT_TOS);
		if (ebt_check_inverse2(optarg))
			ipinfo->invflags |= EBT_IP_TOS;
		i = strtol(optarg, &end, 16);
		if (i < 0 || i > 255 || *end != '\0')
			ebt_print_error2("Problem with specified IP tos");
		ipinfo->tos = i;
		ipinfo->bitmask |= EBT_IP_TOS;
		break;

	case IP_PROTO:
		ebt_check_option2(flags, OPT_PROTO);
		if (ebt_check_inverse2(optarg))
			ipinfo->invflags |= EBT_IP_PROTO;
		i = strtoul(optarg, &end, 10);
		if (*end != '\0') {
			struct protoent *pe;

			pe = getprotobyname(optarg);
			if (pe == NULL)
				ebt_print_error("Unknown specified IP protocol - %s", argv[optind - 1]);
			ipinfo->protocol = pe->p_proto;
		} else {
			ipinfo->protocol = (unsigned char) i;
		}
		ipinfo->bitmask |= EBT_IP_PROTO;
		break;
	default:
		return 0;
	}
	return 1;
}

static void final_check(const struct ebt_u_entry *entry,
   const struct ebt_entry_match *match, const char *name,
   unsigned int hookmask, unsigned int time)
{
	struct ebt_ip_info *ipinfo = (struct ebt_ip_info *)match->data;

	if (entry->ethproto != ETH_P_IP || entry->invflags & EBT_IPROTO) {
		ebt_print_error("For IP filtering the protocol must be "
		            "specified as IPv4");
	} else if (ipinfo->bitmask & (EBT_IP_SPORT|EBT_IP_DPORT) &&
		(!(ipinfo->bitmask & EBT_IP_PROTO) ||
		ipinfo->invflags & EBT_IP_PROTO ||
		(ipinfo->protocol!=IPPROTO_TCP &&
		 ipinfo->protocol!=IPPROTO_UDP &&
		 ipinfo->protocol!=IPPROTO_SCTP &&
		 ipinfo->protocol!=IPPROTO_DCCP))) {
		ebt_print_error("For port filtering the IP protocol must be "
				"either 6 (tcp), 17 (udp), 33 (dccp) or "
				"132 (sctp)");
	} else if ((ipinfo->bitmask & EBT_IP_ICMP) &&
	         (!(ipinfo->bitmask & EBT_IP_PROTO) ||
	            ipinfo->invflags & EBT_IP_PROTO ||
	            ipinfo->protocol != IPPROTO_ICMP)) {
		ebt_print_error("For ICMP filtering the IP protocol must be "
				"1 (icmp)");
	} else if ((ipinfo->bitmask & EBT_IP_IGMP) &&
	         (!(ipinfo->bitmask & EBT_IP_PROTO) ||
	            ipinfo->invflags & EBT_IP_PROTO ||
	            ipinfo->protocol != IPPROTO_IGMP)) {
		ebt_print_error("For IGMP filtering the IP protocol must be "
				"2 (igmp)");
	}
}

static void print(const struct ebt_u_entry *entry,
   const struct ebt_entry_match *match)
{
	struct ebt_ip_info *ipinfo = (struct ebt_ip_info *)match->data;
	int j;

	if (ipinfo->bitmask & EBT_IP_SOURCE) {
		printf("--ip-src ");
		if (ipinfo->invflags & EBT_IP_SOURCE)
			printf("! ");
		for (j = 0; j < 4; j++)
			printf("%d%s",((unsigned char *)&ipinfo->saddr)[j],
			   (j == 3) ? "" : ".");
		printf("%s ", ebt_mask_to_dotted(ipinfo->smsk));
	}
	if (ipinfo->bitmask & EBT_IP_DEST) {
		printf("--ip-dst ");
		if (ipinfo->invflags & EBT_IP_DEST)
			printf("! ");
		for (j = 0; j < 4; j++)
			printf("%d%s", ((unsigned char *)&ipinfo->daddr)[j],
			   (j == 3) ? "" : ".");
		printf("%s ", ebt_mask_to_dotted(ipinfo->dmsk));
	}
	if (ipinfo->bitmask & EBT_IP_TOS) {
		printf("--ip-tos ");
		if (ipinfo->invflags & EBT_IP_TOS)
			printf("! ");
		printf("0x%02X ", ipinfo->tos);
	}
	if (ipinfo->bitmask & EBT_IP_PROTO) {
		struct protoent *pe;

		printf("--ip-proto ");
		if (ipinfo->invflags & EBT_IP_PROTO)
			printf("! ");
		pe = getprotobynumber(ipinfo->protocol);
		if (pe == NULL) {
			printf("%d ", ipinfo->protocol);
		} else {
			printf("%s ", pe->p_name);
		}
	}
	if (ipinfo->bitmask & EBT_IP_SPORT) {
		printf("--ip-sport ");
		if (ipinfo->invflags & EBT_IP_SPORT)
			printf("! ");
		print_port_range(ipinfo->sport);
	}
	if (ipinfo->bitmask & EBT_IP_DPORT) {
		printf("--ip-dport ");
		if (ipinfo->invflags & EBT_IP_DPORT)
			printf("! ");
		print_port_range(ipinfo->dport);
	}
	if (ipinfo->bitmask & EBT_IP_ICMP) {
		printf("--ip-icmp-type ");
		if (ipinfo->invflags & EBT_IP_ICMP)
			printf("! ");
		ebt_print_icmp_type(icmp_codes, ARRAY_SIZE(icmp_codes),
				    ipinfo->icmp_type, ipinfo->icmp_code);
	}
	if (ipinfo->bitmask & EBT_IP_IGMP) {
		printf("--ip-igmp-type ");
		if (ipinfo->invflags & EBT_IP_IGMP)
			printf("! ");
		ebt_print_icmp_type(igmp_types, ARRAY_SIZE(igmp_types),
				    ipinfo->igmp_type, NULL);
	}
}

static int compare(const struct ebt_entry_match *m1,
   const struct ebt_entry_match *m2)
{
	struct ebt_ip_info *ipinfo1 = (struct ebt_ip_info *)m1->data;
	struct ebt_ip_info *ipinfo2 = (struct ebt_ip_info *)m2->data;

	if (ipinfo1->bitmask != ipinfo2->bitmask)
		return 0;
	if (ipinfo1->invflags != ipinfo2->invflags)
		return 0;
	if (ipinfo1->bitmask & EBT_IP_SOURCE) {
		if (ipinfo1->saddr != ipinfo2->saddr)
			return 0;
		if (ipinfo1->smsk != ipinfo2->smsk)
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_DEST) {
		if (ipinfo1->daddr != ipinfo2->daddr)
			return 0;
		if (ipinfo1->dmsk != ipinfo2->dmsk)
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_TOS) {
		if (ipinfo1->tos != ipinfo2->tos)
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_PROTO) {
		if (ipinfo1->protocol != ipinfo2->protocol)
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_SPORT) {
		if (ipinfo1->sport[0] != ipinfo2->sport[0] ||
		   ipinfo1->sport[1] != ipinfo2->sport[1])
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_DPORT) {
		if (ipinfo1->dport[0] != ipinfo2->dport[0] ||
		   ipinfo1->dport[1] != ipinfo2->dport[1])
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_ICMP) {
		if (ipinfo1->icmp_type[0] != ipinfo2->icmp_type[0] ||
		    ipinfo1->icmp_type[1] != ipinfo2->icmp_type[1] ||
		    ipinfo1->icmp_code[0] != ipinfo2->icmp_code[0] ||
		    ipinfo1->icmp_code[1] != ipinfo2->icmp_code[1])
			return 0;
	}
	if (ipinfo1->bitmask & EBT_IP_IGMP) {
		if (ipinfo1->igmp_type[0] != ipinfo2->igmp_type[0] ||
		    ipinfo1->igmp_type[1] != ipinfo2->igmp_type[1])
			return 0;
	}
	return 1;
}

static struct ebt_u_match ip_match =
{
	.name		= "ip",
	.size		= sizeof(struct ebt_ip_info),
	.help		= print_help,
	.init		= init,
	.parse		= parse,
	.final_check	= final_check,
	.print		= print,
	.compare	= compare,
	.extra_ops	= opts,
};

static void _INIT(void)
{
	ebt_register_match(&ip_match);
}