- added description of djurban's branch

[packages/kernel.git] / 2.6.1-rc2-NF-psd-20040107.patch

diff -Nur linux-2.6.1-rc2.org/include/linux/netfilter_ipv4/ipt_psd.h linux-2.6.1-rc2/include/linux/netfilter_ipv4/ipt_psd.h
--- linux-2.6.1-rc2.org/include/linux/netfilter_ipv4/ipt_psd.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.1-rc2/include/linux/netfilter_ipv4/ipt_psd.h	2004-01-07 18:17:50.030389768 +0100
@@ -0,0 +1,40 @@
+#ifndef _IPT_PSD_H
+#define _IPT_PSD_H
+
+#include <linux/param.h>
+#include <linux/types.h>
+
+/*
+ * High port numbers have a lower weight to reduce the frequency of false
+ * positives, such as from passive mode FTP transfers.
+ */
+#define PORT_WEIGHT_PRIV		3
+#define PORT_WEIGHT_HIGH		1
+
+/*
+ * Port scan detection thresholds: at least COUNT ports need to be scanned
+ * from the same source, with no longer than DELAY ticks between ports.
+ */
+#define SCAN_MIN_COUNT			7
+#define SCAN_MAX_COUNT			(SCAN_MIN_COUNT * PORT_WEIGHT_PRIV)
+#define SCAN_WEIGHT_THRESHOLD		SCAN_MAX_COUNT
+#define SCAN_DELAY_THRESHOLD		(HZ * 3)
+
+/*
+ * Keep track of up to LIST_SIZE source addresses, using a hash table of
+ * HASH_SIZE entries for faster lookups, but limiting hash collisions to
+ * HASH_MAX source addresses per the same hash value.
+ */
+#define LIST_SIZE			0x100
+#define HASH_LOG			9
+#define HASH_SIZE			(1 << HASH_LOG)
+#define HASH_MAX			0x10
+
+struct ipt_psd_info {
+	unsigned int weight_threshold;
+	unsigned int delay_threshold;
+	unsigned short lo_ports_weight;
+	unsigned short hi_ports_weight;
+};
+
+#endif /*_IPT_PSD_H*/
diff -Nur linux-2.6.1-rc2.org/net/ipv4/netfilter/ipt_psd.c linux-2.6.1-rc2/net/ipv4/netfilter/ipt_psd.c
--- linux-2.6.1-rc2.org/net/ipv4/netfilter/ipt_psd.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.1-rc2/net/ipv4/netfilter/ipt_psd.c	2004-01-07 18:17:50.031389616 +0100
@@ -0,0 +1,361 @@
+/*
+  This is a module which is used for PSD (portscan detection)
+  Derived from scanlogd v2.1 written by Solar Designer <solar@false.com>
+  and LOG target module.
+
+  Copyright (C) 2000,2001 astaro AG
+
+  This file is distributed under the terms of the GNU General Public
+  License (GPL). Copies of the GPL can be obtained from:
+     ftp://prep.ai.mit.edu/pub/gnu/GPL
+
+  2000-05-04 Markus Hennig <hennig@astaro.de> : initial
+  2000-08-18 Dennis Koslowski <koslowski@astaro.de> : first release
+  2000-12-01 Dennis Koslowski <koslowski@astaro.de> : UDP scans detection added
+  2001-01-02 Dennis Koslowski <koslowski@astaro.de> : output modified
+  2001-02-04 Jan Rekorajski <baggins@pld.org.pl> : converted from target to match
+*/
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <net/tcp.h>
+#include <linux/spinlock.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_psd.h>
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(format, args...)
+#endif
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dennis Koslowski <koslowski@astaro.com>");
+
+#define HF_DADDR_CHANGING   0x01
+#define HF_SPORT_CHANGING   0x02
+#define HF_TOS_CHANGING	    0x04
+#define HF_TTL_CHANGING	    0x08
+            
+/*
+ * Information we keep per each target port
+ */
+struct port {
+	u_int16_t number;      /* port number */ 
+	u_int8_t proto;        /* protocol number */
+	u_int8_t and_flags;    /* tcp ANDed flags */
+	u_int8_t or_flags;     /* tcp ORed flags */
+};
+
+/*
+ * Information we keep per each source address.
+ */
+struct host {
+	struct host *next;		/* Next entry with the same hash */
+	clock_t timestamp;		/* Last update time */
+	struct in_addr src_addr;	/* Source address */
+	struct in_addr dest_addr;	/* Destination address */
+	unsigned short src_port;	/* Source port */
+	int count;			/* Number of ports in the list */
+	int weight;			/* Total weight of ports in the list */
+	struct port ports[SCAN_MAX_COUNT - 1];	/* List of ports */
+	unsigned char tos;		/* TOS */
+	unsigned char ttl;		/* TTL */
+	unsigned char flags;		/* HF_ flags bitmask */
+};
+
+/*
+ * State information.
+ */
+static struct {
+	spinlock_t lock;
+	struct host list[LIST_SIZE];	/* List of source addresses */
+	struct host *hash[HASH_SIZE];	/* Hash: pointers into the list */
+	int index;			/* Oldest entry to be replaced */
+} state;
+
+/*
+ * Convert an IP address into a hash table index.
+ */
+static inline int hashfunc(struct in_addr addr)
+{
+	unsigned int value;
+	int hash;
+
+	value = addr.s_addr;
+	hash = 0;
+	do {
+		hash ^= value;
+	} while ((value >>= HASH_LOG));
+
+	return hash & (HASH_SIZE - 1);
+}
+
+static int
+ipt_psd_match(const struct sk_buff *pskb,
+	      const struct net_device *in,
+	      const struct net_device *out,
+	      const void *matchinfo,
+	      int offset,
+	      const void *hdr,
+	      u_int16_t datalen,
+	      int *hotdrop)
+{
+	struct iphdr *ip_hdr;
+	struct tcphdr *tcp_hdr;
+	struct in_addr addr;
+	u_int16_t src_port,dest_port;
+  	u_int8_t tcp_flags, proto;
+	clock_t now;
+	struct host *curr, *last, **head;
+	int hash, index, count;
+
+	/* Parameters from userspace */
+	const struct ipt_psd_info *psdinfo = matchinfo;
+
+	/* IP header */
+	ip_hdr = pskb->nh.iph;
+
+	/* Sanity check */
+	if (ntohs(ip_hdr->frag_off) & IP_OFFSET) {
+		DEBUGP("PSD: sanity check failed\n");
+		return 0;
+	}
+
+	/* TCP or UDP ? */
+	proto = ip_hdr->protocol;
+
+	if (proto != IPPROTO_TCP && proto != IPPROTO_UDP) {
+		DEBUGP("PSD: protocol not supported\n");
+		return 0;
+	}
+
+	/* Get the source address, source & destination ports, and TCP flags */
+
+	addr.s_addr = ip_hdr->saddr;
+
+	tcp_hdr = (struct tcphdr*)((u_int32_t *)ip_hdr + ip_hdr->ihl);
+