path: root/target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch

Index: linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
===================================================================
--- /dev/null
+++ linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
@@ -0,0 +1,5 @@
+#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
+#	include <linux/netfilter_ipv4/ip_conntrack.h>
+#else /* linux-2.6.20+ */
+#	include <net/netfilter/nf_nat_rule.h>
+#endif
Index: linux-2.6.21.7/include/linux/netfilter/oot_trans.h
===================================================================
--- /dev/null
+++ linux-2.6.21.7/include/linux/netfilter/oot_trans.h
@@ -0,0 +1,14 @@
+/* Out of tree workarounds */
+#include <linux/version.h>
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
+#	define HAVE_MATCHINFOSIZE 1
+#	define HAVE_TARGUSERINFO 1
+#	define HAVE_TARGINFOSIZE 1
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
+#	define nfmark mark
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 21)
+#	define tcp_v4_check(tcph, tcph_sz, s, d, csp) \
+		tcp_v4_check((tcph_sz), (s), (d), (csp))
+#endif
Index: linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
===================================================================
--- /dev/null
+++ linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
@@ -0,0 +1,14 @@
+#ifndef _LINUX_NETFILTER_XT_CHAOS_H
+#define _LINUX_NETFILTER_XT_CHAOS_H 1
+
+enum xt_chaos_target_variant {
+	XTCHAOS_NORMAL,
+	XTCHAOS_TARPIT,
+	XTCHAOS_DELUDE,
+};
+
+struct xt_chaos_target_info {
+	uint8_t variant;
+};
+
+#endif /* _LINUX_NETFILTER_XT_CHAOS_H */
Index: linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
===================================================================
--- /dev/null
+++ linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
@@ -0,0 +1,8 @@
+#ifndef _LINUX_NETFILTER_XT_PORTSCAN_H
+#define _LINUX_NETFILTER_XT_PORTSCAN_H 1
+
+struct xt_portscan_match_info {
+	uint8_t match_stealth, match_syn, match_cn, match_gr;
+};
+
+#endif /* _LINUX_NETFILTER_XT_PORTSCAN_H */
Index: linux-2.6.21.7/net/netfilter/find_match.c
===================================================================
--- /dev/null
+++ linux-2.6.21.7/net/netfilter/find_match.c
@@ -0,0 +1,39 @@
+/*
+    xt_request_find_match
+    by Jan Engelhardt <jengelh [at] gmx de>, 2006 - 2007
+
+    Based upon linux-2.6.18.5/net/netfilter/x_tables.c:
+    Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License version 2 as
+    published by the Free Software Foundation.
+*/
+#include <linux/err.h>
+#include <linux/netfilter_arp.h>
+#include <linux/socket.h>
+#include <linux/netfilter/x_tables.h>
+
+/*
+ * Yeah this code is sub-optimal, but the function is missing in
+ * mainline so far. -jengelh
+ */
+static struct xt_match *xt_request_find_match_lo(int af, const char *name,
+    u8 revision)
+{
+	static const char *const xt_prefix[] = {
+		[AF_INET]  = "ip",
+		[AF_INET6] = "ip6",
+		[NF_ARP]   = "arp",
+	};
+	struct xt_match *match;
+
+	match = try_then_request_module(xt_find_match(af, name, revision),
+		"%st_%s", xt_prefix[af], name);
+	if (IS_ERR(match) || match == NULL)
+		return NULL;
+
+	return match;
+}
+
+/* In case it goes into mainline, let this out-of-tree package compile */
+#define xt_request_find_match xt_request_find_match_lo
Index: linux-2.6.21.7/net/netfilter/Kconfig
===================================================================
--- linux-2.6.21.7.orig/net/netfilter/Kconfig
+++ linux-2.6.21.7/net/netfilter/Kconfig
@@ -287,6 +287,14 @@ config NETFILTER_XTABLES
 
 # alphabetically ordered list of targets
 
+config NETFILTER_XT_TARGET_CHAOS
+	tristate '"CHAOS" target support'
+	depends on NETFILTER_XTABLES
+	help
+	  This option adds a `CHAOS' target.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_TARGET_CLASSIFY
 	tristate '"CLASSIFY" target support'
 	depends on NETFILTER_XTABLES
@@ -315,6 +323,14 @@ config NETFILTER_XT_TARGET_CONNMARK
 	  <file:Documentation/modules.txt>.  The module will be called
 	  ipt_CONNMARK.o.  If unsure, say `N'.
 
+config NETFILTER_XT_TARGET_DELUDE
+	tristate '"DELUDE" target support'
+	depends on NETFILTER_XTABLES
+	help
+	  This option adds a `DELUDE' target.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_TARGET_DSCP
 	tristate '"DSCP" target support'
 	depends on NETFILTER_XTABLES
@@ -563,6 +579,14 @@ config NETFILTER_XT_MATCH_POLICY
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_PORTSCAN
+	tristate '"portscan" match support'
+	depends on NETFILTER_XTABLES
+	help
+	  This option adds a 'portscan' match support.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
 config NETFILTER_XT_MATCH_MULTIPORT
 	tristate "Multiple port match support"
 	depends on NETFILTER_XTABLES
Index: linux-2.6.21.7/net/netfilter/Makefile
===================================================================
--- linux-2.6.21.7.orig/net/netfilter/Makefile
+++ linux-2.6.21.7/net/netfilter/Makefile
@@ -47,6 +47,8 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK
 obj-$(CONFIG_NETFILTER_XT_TARGET_SECMARK) += xt_SECMARK.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o
+obj-$(CONFIG_NETFILTER_XT_TARGET_CHAOS) += xt_CHAOS.o
+obj-$(CONFIG_NETFILTER_XT_TARGET_DELUDE) += xt_DELUDE.o
 
 # matches
 obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o
@@ -74,3 +76,4 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_STRING) 
 obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) += xt_portscan.o
Index: linux-2.6.21.7/net/netfilter/xt_CHAOS.c
===================================================================
--- /dev/null
+++ linux-2.6.21.7/net/netfilter/xt_CHAOS.c
@@ -0,0 +1,200 @@
+/*
+ *	CHAOS target for netfilter
+ *	Copyright © CC Computer Consultants GmbH, 2006 - 2007
+ *	Contact: Jan Engelhardt <jengelh@computergmbh.de>
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License; either version
+ *	2 or 3 as published by the Free Software Foundation.
+ */
+#include <linux/icmp.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/stat.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_tcpudp.h>
+#include <linux/netfilter_ipv4/ipt_REJECT.h>
+#include <net/ip.h>
+#if defined(_LOCAL)
+#	include "xt_CHAOS.h"
+#	include "find_match.c"
+#elif defined(CONFIG_NETFILTER_XT_TARGET_CHAOS) || \
+    defined(CONFIG_NETFILTER_XT_TARGET_CHAOS_MODULE)
+#	include <linux/netfilter/xt_CHAOS.h>
+#	include "find_match.c"
+#else
+#	include "xt_CHAOS.h"
+#	include "find_match.c"
+#endif
+#define PFX KBUILD_MODNAME ": "
+
+/* Module parameters */
+static unsigned int reject_percentage = ~0U * .01;
+static unsigned int delude_percentage = ~0U * .0101;
+module_param(reject_percentage, uint, S_IRUGO | S_IWUSR);
+module_param(delude_percentage, uint, S_IRUGO | S_IWUSR);
+
+/* References to other matches/targets */
+static struct xt_match *xm_tcp;
+static struct xt_target *xt_delude, *xt_reject, *xt_tarpit;
+
+static int have_delude, have_tarpit;
+
+/* Static data for other matches/targets */
+static const struct ipt_reject_info reject_params = {
+	.with = ICMP_HOST_UNREACH,
+};
+
+static const struct xt_tcp tcp_params = {
+	.spts = {0, ~0},
+	.dpts = {0, ~0},
+};
+
+/* CHAOS functions */
+static void xt_chaos_total(const struct xt_chaos_target_info *info,
+    struct sk_buff **pskb, const struct net_device *in,
+    const struct net_device *out, unsigned int hooknum)
+{
+	const struct iphdr *iph = ip_hdr(*pskb);
+	const int protoff       = 4 * iph->ihl;
+	const int offset        = ntohs(iph->frag_off) & IP_OFFSET;
+	const struct xt_target *destiny;
+	int hotdrop = 0, ret;
+
+	ret = xm_tcp->match(*pskb, in, out, xm_tcp, &tcp_params,
+	                    offset, protoff, &hotdrop);
+	if (!ret || hotdrop || (unsigned int)net_random() > delude_percentage)
+		return;
+
+	destiny = (info->variant == XTCHAOS_TARPIT) ? xt_tarpit : xt_delude;
+	destiny->target(pskb, in, out, hooknum, destiny, NULL);
+	return;
+}
+
+static unsigned int chaos_tg(struct sk_buff **pskb,
+    const struct net_device *in, const struct net_device *out,
+    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
+{
+	/*
+	 * Equivalent to:
+	 * -A chaos -m statistic --mode random --probability \
+	 *         $reject_percentage -j REJECT --reject-with host-unreach;
+	 * -A chaos -p tcp -m statistic --mode random --probability \
+	 *         $delude_percentage -j DELUDE;
+	 * -A chaos -j DROP;
+	 */
+	const struct xt_chaos_target_info *info = targinfo;
+	const struct iphdr *iph = ip_hdr(*pskb);
+
+	if ((unsigned int)net_random() <= reject_percentage)
+		return xt_reject->target(pskb, in, out, hooknum, target,
+		       &reject_params);
+
+	/* TARPIT/DELUDE may not be called from the OUTPUT chain */
+	if (iph->protocol == IPPROTO_TCP &&
+	    info->variant != XTCHAOS_NORMAL && hooknum != NF_IP_LOCAL_OUT)
+		xt_chaos_total(info, pskb, in, out, hooknum);
+
+	return NF_DROP;
+}
+
+static int chaos_tg_check(const char *tablename, const void *entry,
+    const struct xt_target *target, void *targinfo, unsigned int hook_mask)
+{
+	const struct xt_chaos_target_info *info = targinfo;
+
+	if (info->variant == XTCHAOS_DELUDE && !have_delude) {
+		printk(KERN_WARNING PFX "Error: Cannot use --delude when "
+		       "DELUDE module not available\n");
+		return false;
+	}
+	if (info->variant == XTCHAOS_TARPIT && !have_tarpit) {
+		printk(KERN_WARNING PFX "Error: Cannot use --tarpit when "
+		       "TARPIT module not available\n");
+		return false;
+	}
+
+	return true;
+}
+
+static struct xt_target chaos_tg_reg = {
+	.name       = "CHAOS",
+	.family     = AF_INET,
+	.table      = "filter",
+	.hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
+	              (1 << NF_IP_LOCAL_OUT),
+	.checkentry = chaos_tg_check,
+	.target     = chaos_tg,
+	.targetsize = sizeof(struct xt_chaos_target_info),
+	.me         = THIS_MODULE,
+};
+
+static int __init chaos_tg_init(void)
+{
+	int ret = -EINVAL;
+
+	xm_tcp = xt_request_find_match(AF_INET, "tcp", 0);
+	if (xm_tcp == NULL) {
+		printk(KERN_WARNING PFX "Error: Could not find or load "
+		       "\"tcp\" match\n");
+		return -EINVAL;
+	}
+
+	xt_reject = xt_request_find_target(AF_INET, "REJECT", 0);
+	if (xt_reject == NULL) {
+		printk(KERN_WARNING PFX "Error: Could not find or load "
+		       "\"REJECT\" target\n");
+		goto out2;
+	}
+
+	xt_tarpit   = xt_request_find_target(AF_INET, "TARPIT", 0);
+	have_tarpit = xt_tarpit != NULL;
+	if (!have_tarpit)
+		printk(KERN_WARNING PFX "Warning: Could not find or load "
+		       "\"TARPIT\" target\n");
+
+	xt_delude   = xt_request_find_target(AF_INET, "DELUDE", 0);
+	have_delude = xt_delude != NULL;
+	if (!have_delude)
+		printk(KERN_WARNING PFX "Warning: Could not find or load "
+		       "\"DELUDE\" target\n");
+
+	if ((ret = xt_register_target(&chaos_tg_reg)) != 0) {
+		printk(KERN_WARNING PFX "xt_register_target returned "
+		       "error %d\n", ret);
+		goto out3;
+	}
+
+	return 0;
+
+ out3:
+ 	if (have_delude)
+ 		module_put(xt_delude->me);
+	if (have_tarpit)
+		module_put(xt_tarpit->me);
+	module_put(xt_reject->me);
+ out2:
+	module_put(xm_tcp->me);
+	return ret;
+}
+
+static void __exit chaos_tg_exit(void)
+{
+	xt_unregister_target(&chaos_tg_reg);
+	module_put(xm_tcp->me);
+	module_put(xt_reject->me);
+	if (have_delude)
+		module_put(xt_delude->me);
+	if (have_tarpit)
+		module_put(xt_tarpit->me);
+	return;
+}
+
+module_init(chaos_tg_init);
+module_exit(chaos_tg_exit);
+MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
+MODULE_DESCRIPTION("netfilter \"CHAOS\" target");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_CHAOS");
Index: linux-2.6.21.7/net/netfilter/xt_DELUDE.c
===================================================================
--- /dev/null
+++ linux-2.6.21.7/net/netfilter/xt_DELUDE.c
@@ -0,0 +1,197 @@
+/*
+ *	DELUDE target
+ *	Copyright © CC Computer Consultants GmbH, 2007
+ *	Contact: Jan Engelhardt <jengelh@computergmbh.de>
+ *
+ *	Based upon linux-2.6.18.5/net/ipv4/netfilter/ipt_REJECT.c:
+ *	(C) 1999-2001 Paul `Rusty' Russell
+ *	(C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ *	xt_DELUDE acts like REJECT, but does reply with SYN-ACK on SYN.
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/netfilter/x_tables.h>
+#ifdef CONFIG_BRIDGE_NETFILTER
+#	include <linux/netfilter_bridge.h>
+#endif
+#include <net/tcp.h>
+#define PFX KBUILD_MODNAME ": "
+
+static void delude_send_reset(struct sk_buff *oldskb, unsigned int hook)
+{
+	struct tcphdr _otcph, *oth, *tcph;
+	unsigned int addr_type;
+	struct sk_buff *nskb;
+	u_int16_t tmp_port;
+	u_int32_t tmp_addr;
+	struct iphdr *niph;
+	bool needs_ack;
+
+	/* IP header checks: fragment. */
+	if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
+		return;
+
+	oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
+				 sizeof(_otcph), &_otcph);
+	if (oth == NULL)
+		return;
+
+	/* No RST for RST. */
+	if (oth->rst)
+		return;
+
+	/* Check checksum */
+	if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
+		return;
+
+	/* We need a linear, writeable skb.  We also need to expand
+	   headroom in case hh_len of incoming interface < hh_len of
+	   outgoing interface */
+	nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
+			       GFP_ATOMIC);
+	if (!nskb)
+		return;
+
+	/* This packet will not be the same as the other: clear nf fields */
+	nf_reset(nskb);
+	nskb->mark = 0;
+	skb_init_secmark(nskb);
+
+	skb_shinfo(nskb)->gso_size = 0;
+	skb_shinfo(nskb)->gso_segs = 0;
+	skb_shinfo(nskb)->gso_type = 0;
+
+	tcph = (struct tcphdr *)(skb_network_header(nskb) + ip_hdrlen(nskb));
+
+	/* Swap source and dest */
+	niph         = ip_hdr(nskb);
+	tmp_addr     = niph->saddr;
+	niph->saddr  = niph->daddr;
+	niph->daddr  = tmp_addr;
+	tmp_port     = tcph->source;
+	tcph->source = tcph->dest;
+	tcph->dest   = tmp_port;
+
+	/* Truncate to length (no data) */
+	tcph->doff    = sizeof(struct tcphdr) / 4;
+	skb_trim(nskb, ip_hdrlen(nskb) + sizeof(struct tcphdr));
+	niph->tot_len = htons(nskb->len);
+
+	if (oth->syn && !oth->ack && !oth->rst && !oth->fin) {
+		/* DELUDE essential part */
+		tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
+		                oldskb->len - ip_hdrlen(oldskb) -
+		                (oth->doff << 2));
+		tcph->seq     = false;
+		tcph->ack     = true;
+	} else {
+		if (!tcph->ack) {
+			needs_ack     = true;
+			tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn +
+			                oth->fin + oldskb->len -
+			                ip_hdrlen(oldskb) - (oth->doff<<2));
+			tcph->seq     = false;
+		} else {
+			needs_ack     = false;
+			tcph->seq     = oth->ack_seq;
+			tcph->ack_seq = false;
+		}
+
+		/* Reset flags */
+		((u_int8_t *)tcph)[13] = 0;
+		tcph->rst = true;
+		tcph->ack = needs_ack;
+	}
+
+	tcph->window  = 0;
+	tcph->urg_ptr = 0;
+
+	/* Adjust TCP checksum */
+	tcph->check = 0;
+	tcph->check = tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
+	              niph->daddr, csum_partial((char *)tcph,
+	              sizeof(struct tcphdr), 0));
+
+	/* Set DF, id = 0 */
+	niph->frag_off = htons(IP_DF);
+	niph->id       = 0;
+
+	addr_type = RTN_UNSPEC;
+#ifdef CONFIG_BRIDGE_NETFILTER
+	if (hook != NF_IP_FORWARD || (nskb->nf_bridge != NULL &&
+	    nskb->nf_bridge->mask & BRNF_BRIDGED))
+#else
+	if (hook != NF_IP_FORWARD)
+#endif
+		addr_type = RTN_LOCAL;
+
+	if (ip_route_me_harder(&nskb, addr_type))
+		goto free_nskb;
+
+	nskb->ip_summed = CHECKSUM_NONE;
+
+	/* Adjust IP TTL */
+	niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
+
+	/* Adjust IP checksum */
+	niph->check = 0;
+	niph->check = ip_fast_csum(skb_network_header(nskb), niph->ihl);
+
+	/* "Never happens" */
+	if (nskb->len > dst_mtu(nskb->dst))
+		goto free_nskb;
+
+	nf_ct_attach(nskb, oldskb);
+
+	NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
+		dst_output);
+	return;
+
+ free_nskb:
+	kfree_skb(nskb);
+}
+
+static unsigned int delude_tg(struct sk_buff **pskb,
+    const struct net_device *in, const struct net_device *out,
+    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
+{
+	/* WARNING: This code causes reentry within iptables.
+	   This means that the iptables jump stack is now crap.  We
+	   must return an absolute verdict. --RR */
+	delude_send_reset(*pskb, hooknum);
+	return NF_DROP;
+}
+
+static struct xt_target delude_tg_reg = {
+	.name       = "DELUDE",
+	.family     = AF_INET,
+	.table      = "filter",
+	.hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD),
+	.target     = delude_tg,
+	.proto      = IPPROTO_TCP,
+	.me         = THIS_MODULE,
+};
+
+static int __init delude_tg_init(void)
+{
+	return xt_register_target(&delude_tg_reg);
+}
+
+static void __exit delude_tg_exit(void)
+{
+	xt_unregister_target(&delude_tg_reg);
+}
+
+module_init(delude_tg_init);
+module_exit(delude_tg_exit);
+MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
+MODULE_DESCRIPTION("netfilter \"DELUDE\" target");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_DELUDE");
Index: linux-2.6.21.7/net/netfilter/xt_portscan.c
===================================================================
--- /dev/null
+++ linux-2.6.21.7/net/netfilter/xt_portscan.c
@@ -0,0 +1,269 @@
+/*
+ *	portscan match for netfilter
+ *	Copyright © CC Computer Consultants GmbH, 2006 - 2007
+ *	Contact: Jan Engelhardt <jengelh@computergmbh.de>
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License; either version
+ *	2 or 3 as published by the Free Software Foundation.
+ */
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/skbuff.h>
+#include <linux/stat.h>
+#include <linux/tcp.h>
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_tcpudp.h>
+#include <net/netfilter/nf_nat_rule.h>
+#if defined(_LOCAL)
+#	include "xt_portscan.h"
+#elif defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) || \
+    defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN_MODULE)
+#	include <linux/netfilter/xt_portscan.h>
+#else
+#	include "xt_portscan.h"
+#endif
+#define PFX KBUILD_MODNAME ": "
+
+enum {
+	TCP_FLAGS_ALL3 = TCP_FLAG_FIN | TCP_FLAG_RST | TCP_FLAG_SYN,
+	TCP_FLAGS_ALL4 = TCP_FLAGS_ALL3 | TCP_FLAG_ACK,
+	TCP_FLAGS_ALL6 = TCP_FLAGS_ALL4 | TCP_FLAG_PSH | TCP_FLAG_URG,
+};
+
+/* Module parameters */
+static unsigned int
+	connmark_mask = ~0,
+	packet_mask   = ~0,
+	mark_seen     = 0x9,
+	mark_synrcv   = 0x1,
+	mark_closed   = 0x2,
+	mark_synscan  = 0x3,
+	mark_estab1   = 0x4,
+	mark_estab2   = 0x5,
+	mark_cnscan   = 0x6,
+	mark_grscan   = 0x7,
+	mark_valid    = 0x8;
+
+module_param(connmark_mask, uint, S_IRUGO | S_IWUSR);
+module_param(packet_mask,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_seen,     uint, S_IRUGO | S_IWUSR);
+module_param(mark_synrcv,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_closed,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_synscan,  uint, S_IRUGO | S_IWUSR);
+module_param(mark_estab1,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_estab2,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_cnscan,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_grscan,   uint, S_IRUGO | S_IWUSR);
+module_param(mark_valid,    uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(connmark_mask, "only set specified bits in connection mark");
+MODULE_PARM_DESC(packet_mask,   "only set specified bits in packet mark");
+MODULE_PARM_DESC(mark_seen,     "nfmark value for packet-seen state");
+MODULE_PARM_DESC(mark_synrcv,   "connmark value for SYN Received state");
+MODULE_PARM_DESC(mark_closed,   "connmark value for closed state");
+MODULE_PARM_DESC(mark_synscan,  "connmark value for SYN Scan state");
+MODULE_PARM_DESC(mark_estab1,   "connmark value for Established-1 state");
+MODULE_PARM_DESC(mark_estab2,   "connmark value for Established-2 state");
+MODULE_PARM_DESC(mark_cnscan,   "connmark value for Connect Scan state");
+MODULE_PARM_DESC(mark_grscan,   "connmark value for Grab Scan state");
+MODULE_PARM_DESC(mark_valid,    "connmark value for Valid state");
+
+/* TCP flag functions */
+static inline bool tflg_ack4(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_ACK;
+}
+
+static inline bool tflg_ack6(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL6) == TCP_FLAG_ACK;
+}
+
+static inline bool tflg_fin(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_FIN;
+}
+
+static inline bool tflg_rst(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_RST;
+}
+
+static inline bool tflg_rstack(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
+	       (TCP_FLAG_ACK | TCP_FLAG_RST);
+}
+
+static inline bool tflg_syn(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_SYN;
+}
+
+static inline bool tflg_synack(const struct tcphdr *th)
+{
+	return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
+	       (TCP_FLAG_SYN | TCP_FLAG_ACK);
+}
+
+/* portscan functions */
+static inline bool portscan_mt_stealth(const struct tcphdr *th)
+{
+	/*
+	 * "Connection refused" replies to our own probes must not be matched.
+	 */
+	if (tflg_rstack(th))
+		return false;
+
+	if (tflg_rst(th) && printk_ratelimit()) {
+		printk(KERN_WARNING PFX "Warning: Pure RST received\n");
+		return false;
+	}
+
+	/*
+	 * -p tcp ! --syn -m conntrack --ctstate INVALID: Looking for non-start
+	 * packets that are not associated with any connection -- this will
+	 * match most scan types (NULL, XMAS, FIN) and ridiculous flag
+	 * combinations (SYN-RST, SYN-FIN, SYN-FIN-RST, FIN-RST, etc.).
+	 */
+	return !tflg_syn(th);
+}
+
+static inline unsigned int portscan_mt_full(int mark,
+    enum ip_conntrack_info ctstate, bool loopback, const struct tcphdr *tcph,
+    unsigned int payload_len)
+{
+	if (mark == mark_estab2) {
+		/*
+		 * -m connmark --mark $ESTAB2
+		 */
+		if (tflg_ack4(tcph) && payload_len == 0)
+			return mark; /* keep mark */
+		else if (tflg_rst(tcph) || tflg_fin(tcph))
+			return mark_grscan;
+		else
+			return mark_valid;
+	} else if (mark == mark_estab1) {
+		/*
+		 * -m connmark --mark $ESTAB1
+		 */
+		if (tflg_rst(tcph) || tflg_fin(tcph))
+			return mark_cnscan;
+		else if (!loopback && tflg_ack4(tcph) && payload_len == 0)
+			return mark_estab2;
+		else
+			return mark_valid;
+	} else if (mark == mark_synrcv) {
+		/*
+		 * -m connmark --mark $SYN
+		 */
+		if (loopback && tflg_synack(tcph))
+			return mark; /* keep mark */
+		else if (loopback && tflg_rstack(tcph))
+			return mark_closed;
+		else if (tflg_ack6(tcph))
+			return mark_estab1;
+		else
+			return mark_synscan;
+	} else if (ctstate == IP_CT_NEW && tflg_syn(tcph)) {
+		/*
+		 * -p tcp --syn --ctstate NEW
+		 */
+		return mark_synrcv;
+	}
+	return mark;
+}
+
+static int portscan_mt(const struct sk_buff *skb,
+    const struct net_device *in, const struct net_device *out,
+    const struct xt_match *match, const void *matchinfo, int offset,
+    unsigned int protoff, int *hotdrop)
+{
+	const struct xt_portscan_match_info *info = matchinfo;
+	enum ip_conntrack_info ctstate;
+	const struct tcphdr *tcph;
+	struct nf_conn *ctdata;
+	struct tcphdr tcph_buf;
+
+	tcph = skb_header_pointer(skb, protoff, sizeof(tcph_buf), &tcph_buf);
+	if (tcph == NULL)
+		return false;
+
+	/* Check for invalid packets: -m conntrack --ctstate INVALID */
+	if ((ctdata = nf_ct_get(skb, &ctstate)) == NULL) {
+		if (info->match_stealth)
+			return portscan_mt_stealth(tcph);
+		/*
+		 * If @ctdata is NULL, we cannot match the other scan
+		 * types, return.
+		 */
+		return false;
+	}
+
+	/*
+	 * If -m portscan was previously applied to this packet, the rules we
+	 * simulate must not be run through again. And for speedup, do not call
+	 * it either when the connection is already VALID.
+	 */
+	if ((ctdata->mark & connmark_mask) == mark_valid ||
+	     (skb->mark & packet_mask) != mark_seen) {
+		unsigned int n;
+
+		n = portscan_mt_full(ctdata->mark & connmark_mask, ctstate,
+		    in == &loopback_dev, tcph,
+		    skb->len - protoff - 4 * tcph->doff);
+
+		ctdata->mark = (ctdata->mark & ~connmark_mask) | n;
+		((struct sk_buff *)skb)->mark =
+			(skb->mark & ~packet_mask) ^ mark_seen;
+	}
+
+	return (info->match_syn && ctdata->mark == mark_synscan) ||
+	       (info->match_cn && ctdata->mark == mark_cnscan) ||
+	       (info->match_gr && ctdata->mark == mark_grscan);
+}
+
+static int portscan_mt_check(const char *tablename, const void *entry,
+    const struct xt_match *match, void *matchinfo, unsigned int hook_mask)
+{
+	const struct xt_portscan_match_info *info = matchinfo;
+
+	if ((info->match_stealth & ~1) || (info->match_syn & ~1) ||
+	    (info->match_cn & ~1) || (info->match_gr & ~1)) {
+		printk(KERN_WARNING PFX "Invalid flags\n");
+		return false;
+	}
+	return true;
+}
+
+static struct xt_match portscan_mt_reg __read_mostly = {
+	.name       = "portscan",
+	.family     = AF_INET,
+	.match      = portscan_mt,
+	.checkentry = portscan_mt_check,
+	.matchsize  = sizeof(struct xt_portscan_match_info),
+	.proto      = IPPROTO_TCP,
+	.me         = THIS_MODULE,
+};
+
+static int __init portscan_mt_init(void)
+{
+	return xt_register_match(&portscan_mt_reg);
+}
+
+static void __exit portscan_mt_exit(void)
+{
+	xt_unregister_match(&portscan_mt_reg);
+	return;
+}
+
+module_init(portscan_mt_init);
+module_exit(portscan_mt_exit);
+MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
+MODULE_DESCRIPTION("netfilter \"portscan\" match");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_portscan");