path: root/target/linux/generic-2.4/patches/609-netfilter_string.patch

--- /dev/null
+++ b/include/linux/netfilter_ipv4/ipt_string.h
@@ -0,0 +1,18 @@
+#ifndef _IPT_STRING_H
+#define _IPT_STRING_H
+
+#define IPT_STRING_MAX_PATTERN_SIZE 128
+#define IPT_STRING_MAX_ALGO_NAME_SIZE 16
+
+struct ipt_string_info
+{
+	u_int16_t from_offset;
+	u_int16_t to_offset;
+	char	  algo[IPT_STRING_MAX_ALGO_NAME_SIZE];
+	char 	  pattern[IPT_STRING_MAX_PATTERN_SIZE];
+	u_int8_t  patlen;
+	u_int8_t  invert;
+	struct ts_config __attribute__((aligned(8))) *config;
+};
+
+#endif /*_IPT_STRING_H*/
--- a/net/ipv4/netfilter/Config.in
+++ b/net/ipv4/netfilter/Config.in
@@ -61,6 +61,7 @@ if [ "$CONFIG_IP_NF_IPTABLES" != "n" ]; 
   fi
   if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
     dep_tristate '  Unclean match support (EXPERIMENTAL)' CONFIG_IP_NF_MATCH_UNCLEAN $CONFIG_IP_NF_IPTABLES
+    dep_tristate '  String match support (EXPERIMENTAL) ' CONFIG_IP_NF_MATCH_STRING $CONFIG_IP_NF_IPTABLES
     dep_tristate '  Owner match support (EXPERIMENTAL)' CONFIG_IP_NF_MATCH_OWNER $CONFIG_IP_NF_IPTABLES
     dep_tristate '  Layer 7 match support (EXPERIMENTAL)' CONFIG_IP_NF_MATCH_LAYER7 $CONFIG_IP_NF_CONNTRACK
     dep_mbool '  Layer 7 debugging output (EXPERIMENTAL)' CONFIG_IP_NF_MATCH_LAYER7_DEBUG $CONFIG_IP_NF_MATCH_LAYER7
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_string.c
@@ -0,0 +1,99 @@
+/* String matching match for iptables
+ * 
+ * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
+ *
+ * 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/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_string.h>
+#include "textsearch/textsearch.h"
+#include "textsearch/textsearch.c"
+#include "textsearch/ts_bm.c"
+#include "textsearch/ts_kmp.c"
+
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
+MODULE_DESCRIPTION("IP tables string match module");
+MODULE_LICENSE("GPL");
+
+static int match(const struct sk_buff *skb,
+		 const struct net_device *in,
+		 const struct net_device *out,
+		 const void *matchinfo,
+		 int offset,
+		 int *hotdrop)
+{
+	struct iphdr *ip = skb->nh.iph;
+	struct ts_state state;
+	struct ipt_string_info *conf = (struct ipt_string_info *) matchinfo;
+	char *buf = (char *)ip+(ip->ihl*4);
+	int len = ntohs(ip->tot_len)-(ip->ihl*4);
+
+	memset(&state, 0, sizeof(struct ts_state));
+
+	return (textsearch_find_continuous(conf->config, &state, buf, len) != UINT_MAX) && !conf->invert;
+}
+
+#define STRING_TEXT_PRIV(m) ((struct ipt_string_info *) m)
+
+static int checkentry(const char *tablename,
+		      const struct ipt_ip *ip,
+		      void *matchinfo,
+		      unsigned int matchsize,
+		      unsigned int hook_mask)
+{
+	struct ipt_string_info *conf = matchinfo;
+	struct ts_config *ts_conf;
+
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_string_info)))
+		return 0;
+
+	/* Damn, can't handle this case properly with iptables... */
+	if (conf->from_offset > conf->to_offset)
+		return 0;
+
+	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
+				     GFP_KERNEL, TS_AUTOLOAD);
+	if (IS_ERR(ts_conf))
+		return 0;
+
+	conf->config = ts_conf;
+
+	return 1;
+}
+
+static void destroy(void *matchinfo, unsigned int matchsize)
+{
+	textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
+}
+
+static struct ipt_match string_match = {
+	.name 		= "string",
+	.match 		= match,
+	.checkentry	= checkentry,
+	.destroy 	= destroy,
+	.me 		= THIS_MODULE
+};
+
+static int __init init(void)
+{
+	init_bm();
+	init_kmp();
+	return ipt_register_match(&string_match);
+}
+
+static void __exit fini(void)
+{
+	exit_kmp();
+	exit_bm();
+	ipt_unregister_match(&string_match);
+}
+
+module_init(init);
+module_exit(fini);
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_IP_NF_MATCH_STATE) += ipt_s
 obj-$(CONFIG_IP_NF_MATCH_CONNMARK) += ipt_connmark.o
 obj-$(CONFIG_IP_NF_MATCH_CONNTRACK) += ipt_conntrack.o
 obj-$(CONFIG_IP_NF_MATCH_UNCLEAN) += ipt_unclean.o
+obj-$(CONFIG_IP_NF_MATCH_STRING) += ipt_string.o
 obj-$(CONFIG_IP_NF_MATCH_TCPMSS) += ipt_tcpmss.o
 obj-$(CONFIG_IP_NF_MATCH_LAYER7) += ipt_layer7.o
 
--- /dev/null
+++ b/net/ipv4/netfilter/textsearch/textsearch.c
@@ -0,0 +1,305 @@
+/*
+ * lib/textsearch.c	Generic text search interface
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Thomas Graf <tgraf@suug.ch>
+ * 		Pablo Neira Ayuso <pablo@eurodev.net>
+ *
+ * ==========================================================================
+ *
+ * INTRODUCTION
+ *
+ *   The textsearch infrastructure provides text searching facitilies for
+ *   both linear and non-linear data. Individual search algorithms are
+ *   implemented in modules and chosen by the user.
+ *
+ * ARCHITECTURE
+ *
+ *      User
+ *     +----------------+
+ *     |        finish()|<--------------(6)-----------------+
+ *     |get_next_block()|<--------------(5)---------------+ |
+ *     |                |                     Algorithm   | |
+ *     |                |                    +------------------------------+
+ *     |                |                    |  init()   find()   destroy() |
+ *     |                |                    +------------------------------+
+ *     |                |       Core API           ^       ^          ^
+ *     |                |      +---------------+  (2)     (4)        (8)
+ *     |             (1)|----->| prepare()     |---+       |          |
+ *     |             (3)|----->| find()/next() |-----------+          |
+ *     |             (7)|----->| destroy()     |----------------------+
+ *     +----------------+      +---------------+
+ *  
+ *   (1) User configures a search by calling _prepare() specifying the
+ *       search parameters such as the pattern and algorithm name.
+ *   (2) Core requests the algorithm to allocate and initialize a search
+ *       configuration according to the specified parameters.
+ *   (3) User starts the search(es) by calling _find() or _next() to
+ *       fetch subsequent occurrences. A state variable is provided
+ *       to the algorihtm to store persistant variables.
+ *   (4) Core eventually resets the search offset and forwards the find()
+ *       request to the algorithm.
+ *   (5) Algorithm calls get_next_block() provided by the user continously
+ *       to fetch the data to be searched in block by block.
+ *   (6) Algorithm invokes finish() after the last call to get_next_block
+ *       to clean up any leftovers from get_next_block. (Optional)
+ *   (7) User destroys the configuration by calling _destroy().
+ *   (8) Core notifies the algorithm to destroy algorithm specific
+ *       allocations. (Optional)
+ *
+ * USAGE
+ *
+ *   Before a search can be performed, a configuration must be created
+ *   by calling textsearch_prepare() specyfing the searching algorithm and
+ *   the pattern to look for. The returned configuration may then be used
+ *   for an arbitary amount of times and even in parallel as long as a
+ *   separate struct ts_state variable is provided to every instance.
+ *
+ *   The actual search is performed by either calling textsearch_find_-
+ *   continuous() for linear data or by providing an own get_next_block()
+ *   implementation and calling textsearch_find(). Both functions return
+ *   the position of the first occurrence of the patern or UINT_MAX if
+ *   no match was found. Subsequent occurences can be found by calling
+ *   textsearch_next() regardless of the linearity of the data.
+ *
+ *   Once you're done using a configuration it must be given back via
+ *   textsearch_destroy.
+ *
+ * EXAMPLE
+ *
+ *   int pos;
+ *   struct ts_config *conf;
+ *   struct ts_state state;
+ *   const char *pattern = "chicken";
+ *   const char *example = "We dance the funky chicken";
+ *
+ *   conf = textsearch_prepare("kmp", pattern, strlen(pattern),
+ *                             GFP_KERNEL, TS_AUTOLOAD);
+ *   if (IS_ERR(conf)) {
+ *       err = PTR_ERR(conf);
+ *       goto errout;
+ *   }
+ *
+ *   pos = textsearch_find_continuous(conf, &state, example, strlen(example));
+ *   if (pos != UINT_MAX)
+ *       panic("Oh my god, dancing chickens at %d\n", pos);
+ *
+ *   textsearch_destroy(conf);
+ *
+ * ==========================================================================
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4/lockhelp.h>
+#include "textsearch.h"
+
+static LIST_HEAD(ts_ops);
+static spinlock_t ts_mod_lock = SPIN_LOCK_UNLOCKED;
+static DECLARE_RWLOCK(ts_ops_lock);
+
+static inline struct ts_ops *lookup_ts_algo(const char *name)
+{
+	struct ts_ops *o;
+
+	read_lock(&ts_ops_lock);
+	list_for_each_entry(o, &ts_ops, list) {
+		if (!strcmp(name, o->name)) {
+			MOD_INC_USE_COUNT;
+			read_unlock(&ts_ops_lock);
+			return o;
+		}
+	}
+	read_unlock(&ts_ops_lock);
+
+	return NULL;
+}
+
+/**
+ * textsearch_register - register a textsearch module
+ * @ops: operations lookup table
+ *
+ * This function must be called by textsearch modules to announce
+ * their presence. The specified &@ops must have %name set to a
+ * unique identifier and the callbacks find(), init(), get_pattern(),
+ * and get_pattern_len() must be implemented.
+ *
+ * Returns 0 or -EEXISTS if another module has already registered
+ * with same name.
+ */
+int textsearch_register(struct ts_ops *ops)
+{
+	int err = -EEXIST;
+	struct ts_ops *o;
+
+	if (ops->name == NULL || ops->find == NULL || ops->init == NULL ||
+	    ops->get_pattern == NULL || ops->get_pattern_len == NULL)
+		return -EINVAL;
+
+	spin_lock(&ts_mod_lock);
+	list_for_each_entry(o, &ts_ops, list) {
+		if (!strcmp(ops->name, o->name))
+			goto errout;
+	}
+
+	write_lock(&ts_ops_lock);
+	list_add_tail(&ops->list, &ts_ops);
+	write_unlock(&ts_ops_lock);
+
+	err = 0;
+errout:
+	spin_unlock(&ts_mod_lock);
+	return err;
+}
+
+/**
+ * textsearch_unregister - unregister a textsearch module
+ * @ops: operations lookup table
+ *
+ * This function must be called by textsearch modules to announce
+ * their disappearance for examples when the module gets unloaded.
+ * The &ops parameter must be the same as the one during the
+ * registration.
+ *
+ * Returns 0 on success or -ENOENT if no matching textsearch
+ * registration was found.
+ */
+int textsearch_unregister(struct ts_ops *ops)
+{
+	int err = 0;
+	struct ts_ops *o;
+
+	spin_lock(&ts_mod_lock);
+	list_for_each_entry(o, &ts_ops, list) {
+		if (o == ops) {
+			write_lock(&ts_ops_lock);
+			list_del(&o->list);
+			write_unlock(&ts_ops_lock);
+			goto out;
+		}
+	}
+
+	err = -ENOENT;
+out:
+	spin_unlock(&ts_mod_lock);
+	return err;
+}
+
+struct ts_linear_state
+{
+	unsigned int	len;
+	const void	*data;
+};
+
+static unsigned int get_linear_data(unsigned int consumed, const u8 **dst,
+				    struct ts_config *conf,
+				    struct ts_state *state)
+{
+	struct ts_linear_state *st = (struct ts_linear_state *) state->cb;
+
+	if (likely(consumed < st->len)) {
+		*dst = st->data + consumed;
+		return st->len - consumed;
+	}
+
+	return 0;
+}
+
+/**
+ * textsearch_find_continuous - search a pattern in continuous/linear data
+ * @conf: search configuration
+ * @state: search state
+ * @data: data to search in
+ * @len: length of data
+ *
+ * A simplified version of textsearch_find() for continuous/linear data.
+ * Call textsearch_next() to retrieve subsequent matches.
+ *
+ * Returns the position of first occurrence of the pattern or
+ * UINT_MAX if no occurrence was found.
+ */ 
+unsigned int textsearch_find_continuous(struct ts_config *conf,
+					struct ts_state *state,
+					const void *data, unsigned int len)
+{
+	struct ts_linear_state *st = (struct ts_linear_state *) state->cb;
+
+	conf->get_next_block = get_linear_data;
+	st->data = data;
+	st->len = len;
+
+	return textsearch_find(conf, state);
+}
+
+/**
+ * textsearch_prepare - Prepare a search
+ * @algo: name of search algorithm
+ * @pattern: pattern data
+ * @len: length of pattern
+ * @gfp_mask: allocation mask
+ * @flags: search flags
+ *
+ * Looks up the search algorithm module and creates a new textsearch
+ * configuration for the specified pattern. Upon completion all
+ * necessary refcnts are held and the configuration must be put back
+ * using textsearch_put() after usage.
+ *
+ * Note: The format of the pattern may not be compatible between
+ *       the various search algorithms.
+ *
+ * Returns a new textsearch configuration according to the specified
+ *         parameters or a ERR_PTR().
+ */
+struct ts_config *textsearch_prepare(const char *algo, const void *pattern,
+				     unsigned int len, gfp_t gfp_mask, int flags)
+{
+	int err = -ENOENT;
+	struct ts_config *conf;
+	struct ts_ops *ops;
+	
+	ops = lookup_ts_algo(algo);
+
+	if (ops == NULL)
+		goto errout;
+
+	conf = ops->init(pattern, len, gfp_mask);
+	if (IS_ERR(conf)) {
+		err = PTR_ERR(conf);
+		goto errout;
+	}
+
+	conf->ops = ops;
+	return conf;
+
+errout:
+	if (ops)
+		MOD_DEC_USE_COUNT;
+		
+	return ERR_PTR(err);
+}
+
+/**
+ * textsearch_destroy - destroy a search configuration
+ * @conf: search configuration
+ *
+ * Releases all references of the configuration and frees
+ * up the memory.
+ */
+void textsearch_destroy(struct ts_config *conf)
+{
+	if (conf->ops) {
+		if (conf->ops->destroy)
+			conf->ops->destroy(conf);
+		MOD_DEC_USE_COUNT;
+	}
+
+	kfree(conf);
+}
+
--- /dev/null
+++ b/net/ipv4/netfilter/textsearch/textsearch.h
@@ -0,0 +1,182 @@
+#ifndef __LINUX_TEXTSEARCH_H
+#define __LINUX_TEXTSEARCH_H
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+typedef int gfp_t;
+struct ts_config;
+
+/**
+ * TS_AUTOLOAD - Automatically load textsearch modules when needed
+ */
+#define TS_AUTOLOAD	1
+
+/**
+ * struct ts_state - search state
+ * @offset: offset for next match
+ * @cb: control buffer, for persistant variables of get_next_block()
+ */
+struct ts_state
+{
+	unsigned int		offset;
+	char			cb[40];
+};
+
+/**
+ * struct ts_ops - search module operations
+ * @name: name of search algorithm
+ * @init: initialization function to prepare a search
+ * @find: find the next occurrence of the pattern
+ * @destroy: destroy algorithm specific parts of a search configuration
+ * @get_pattern: return head of pattern
+ * @get_pattern_len: return length of pattern
+ * @owner: module reference to algorithm
+ */
+struct ts_ops
+{
+	const char		*name;
+	struct ts_config *	(*init)(const void *, unsigned int, gfp_t);
+	unsigned int		(*find)(struct ts_config *,
+					struct ts_state *);
+	void			(*destroy)(struct ts_config *);
+	void *			(*get_pattern)(struct ts_config *);
+	unsigned int		(*get_pattern_len)(struct ts_config *);
+	struct module		*owner;
+	struct list_head	list;
+};
+
+/**
+ * struct ts_config - search configuration
+ * @ops: operations of chosen algorithm
+ * @get_next_block: callback to fetch the next block to search in
+ * @finish: callback to finalize a search
+ */
+struct ts_config
+{
+	struct ts_ops		*ops;
+
+	/**
+	 * get_next_block - fetch next block of data
+	 * @consumed: number of bytes consumed by the caller
+	 * @dst: destination buffer
+	 * @conf: search configuration
+	 * @state: search state
+	 *
+	 * Called repeatedly until 0 is returned. Must assign the
+	 * head of the next block of data to &*dst and return the length
+	 * of the block or 0 if at the end. consumed == 0 indicates
+	 * a new search. May store/read persistant values in state->cb.
+	 */
+	unsigned int		(*get_next_block)(unsigned int consumed,
+						  const u8 **dst,
+						  struct ts_config *conf,
+						  struct ts_state *state);
+
+	/**
+	 * finish - finalize/clean a series of get_next_block() calls
+	 * @conf: search configuration
+	 * @state: search state
+	 *
+	 * Called after the last use of get_next_block(), may be used
+	 * to cleanup any leftovers.
+	 */
+	void			(*finish)(struct ts_config *conf,
+					  struct ts_state *state);
+};
+
+/**
+ * textsearch_next - continue searching for a pattern
+ * @conf: search configuration
+ * @state: search state
+ *
+ * Continues a search looking for more occurrences of the pattern.
+ * textsearch_find() must be called to find the first occurrence
+ * in order to reset the state.
+ *
+ * Returns the position of the next occurrence of the pattern or
+ * UINT_MAX if not match was found.
+ */ 
+static inline unsigned int textsearch_next(struct ts_config *conf,
+					   struct ts_state *state)
+{
+	unsigned int ret = conf->ops->find(conf, state);
+
+	if (conf->finish)
+		conf->finish(conf, state);
+
+	return ret;
+}
+
+/**
+ * textsearch_find - start searching for a pattern
+ * @conf: search configuration
+ * @state: search state
+ *
+ * Returns the position of first occurrence of the pattern or
+ * UINT_MAX if no match was found.
+ */ 
+static inline unsigned int textsearch_find(struct ts_config *conf,
+					   struct ts_state *state)
+{
+	state->offset = 0;
+	return textsearch_next(conf, state);
+}
+
+/**
+ * textsearch_get_pattern - return head of the pattern
+ * @conf: search configuration
+ */
+static inline void *textsearch_get_pattern(struct ts_config *conf)
+{
+	return conf->ops->get_pattern(conf);
+}
+
+/**
+ * textsearch_get_pattern_len - return length of the pattern
+ * @conf: search configuration
+ */
+static inline unsigned int textsearch_get_pattern_len(struct ts_config *conf)
+{
+	return conf->ops->get_pattern_len(conf);
+}
+
+extern int textsearch_register(struct ts_ops *);
+extern int textsearch_unregister(struct ts_ops *);
+extern struct ts_config *textsearch_prepare(const char *, const void *,
+					    unsigned int, gfp_t, int);
+extern void textsearch_destroy(struct ts_config *conf);
+extern unsigned int textsearch_find_continuous(struct ts_config *,
+					       struct ts_state *,
+					       const void *, unsigned int);
+
+
+#define TS_PRIV_ALIGNTO	8
+#define TS_PRIV_ALIGN(len) (((len) + TS_PRIV_ALIGNTO-1) & ~(TS_PRIV_ALIGNTO-1))
+
+static inline struct ts_config *alloc_ts_config(size_t payload,
+						gfp_t gfp_mask)
+{
+	struct ts_config *conf;
+
+	conf = kmalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
+	if (conf == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	memset(conf, 0, TS_PRIV_ALIGN(sizeof(*conf)) + payload);
+	return conf;
+}
+
+static inline void *ts_config_priv(struct ts_config *conf)
+{
+	return ((u8 *) conf + TS_PRIV_ALIGN(sizeof(struct ts_config)));
+}
+
+#endif /* __KERNEL__ */
+
+#endif
--- /dev/null
+++ b/net/ipv4/netfilter/textsearch/ts_bm.c
@@ -0,0 +1,190 @@
+/*
+ * lib/ts_bm.c		Boyer-Moore text search implementation
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Pablo Neira Ayuso <pablo@eurodev.net>
+ *
+ * ==========================================================================
+ * 
+ *   Implements Boyer-Moore string matching algorithm:
+ *
+ *   [1] A Fast String Searching Algorithm, R.S. Boyer and Moore.
+ *       Communications of the Association for Computing Machinery, 
+ *       20(10), 1977, pp. 762-772.
+ *       http://www.cs.utexas.edu/users/moore/publications/fstrpos.pdf
+ *
+ *   [2] Handbook of Exact String Matching Algorithms, Thierry Lecroq, 2004
+ *       http://www-igm.univ-mlv.fr/~lecroq/string/string.pdf
+ *
+ *   Note: Since Boyer-Moore (BM) performs searches for matchings from right 
+ *   to left, it's still possible that a matching could be spread over 
+ *   multiple blocks, in that case this algorithm won't find any coincidence.
+ *   
+ *   If you're willing to ensure that such thing won't ever happen, use the
+ *   Knuth-Pratt-Morris (KMP) implementation instead. In conclusion, choose 
+ *   the proper string search algorithm depending on your setting. 
+ *
+ *   Say you're using the textsearch infrastructure for filtering, NIDS or 
+ *   any similar security focused purpose, then go KMP. Otherwise, if you 
+ *   really care about performance, say you're classifying packets to apply
+ *   Quality of Service (QoS) policies, and you don't mind about possible
+ *   matchings spread over multiple fragments, then go BM.
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include "textsearch.h"
+
+/* Alphabet size, use ASCII */
+#define ASIZE 256
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(args, format...)
+#endif
+
+struct ts_bm
+{
+	u8 *		pattern;
+	unsigned int	patlen;
+	unsigned int 	bad_shift[ASIZE];
+	unsigned int	good_shift[0];
+};
+
+static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
+{
+	struct ts_bm *bm = ts_config_priv(conf);
+	unsigned int i, text_len, consumed = state->offset;
+	const u8 *text;
+	int shift = bm->patlen, bs;
+
+	for (;;) {
+		text_len = conf->get_next_block(consumed, &text, conf, state);
+
+		if (unlikely(text_len == 0))
+			break;
+
+		while (shift < text_len) {
+			DEBUGP("Searching in position %d (%c)\n", 
+				shift, text[shift]);
+			for (i = 0; i < bm->patlen; i++) 
+			     if (text[shift-i] != bm->pattern[bm->patlen-1-i])
+				     goto next;
+
+			/* London calling... */
+			DEBUGP("found!\n");
+			return consumed += (shift-(bm->patlen-1));
+
+next:			bs = bm->bad_shift[text[shift-i]];
+
+			/* Now jumping to... */
+			shift = max_t(int, shift-i+bs, shift+bm->good_shift[i]);
+		}
+		consumed += text_len;
+	}
+
+	return UINT_MAX;
+}
+
+static int subpattern(u8 *pattern, int i, int j, int g)
+{
+	int x = i+g-1, y = j+g-1, ret = 0;
+
+	while(pattern[x--] == pattern[y--]) {
+		if (y < 0) {
+			ret = 1;
+			break;
+		}
+		if (--g == 0) {
+			ret = pattern[i-1] != pattern[j-1];
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void bm_compute_prefix_tbl(struct ts_bm *bm, const u8 *pattern,
+			       unsigned int len)
+{
+	int i, j, g;
+
+	for (i = 0; i < ASIZE; i++)
+		bm->bad_shift[i] = len;
+	for (i = 0; i < len - 1; i++)
+		bm->bad_shift[pattern[i]] = len - 1 - i;
+
+	/* Compute the good shift array, used to match reocurrences 
+	 * of a subpattern */
+	bm->good_shift[0] = 1;
+	for (i = 1; i < bm->patlen; i++)
+		bm->good_shift[i] = bm->patlen;
+        for (i = bm->patlen-1, g = 1; i > 0; g++, i--) {
+		for (j = i-1; j >= 1-g ; j--)
+			if (subpattern(bm->pattern, i, j, g)) {
+				bm->good_shift[g] = bm->patlen-j-g;
+				break;
+			}
+	}
+}
+
+static struct ts_config *bm_init(const void *pattern, unsigned int len,
+				 gfp_t gfp_mask)
+{
+	struct ts_config *conf;
+	struct ts_bm *bm;
+	unsigned int prefix_tbl_len = len * sizeof(unsigned int);
+	size_t priv_size = sizeof(*bm) + len + prefix_tbl_len;
+
+	conf = alloc_ts_config(priv_size, gfp_mask);
+	if (IS_ERR(conf))
+		return conf;
+
+	bm = ts_config_priv(conf);
+	bm->patlen = len;
+	bm->pattern = (u8 *) bm->good_shift + prefix_tbl_len;
+	bm_compute_prefix_tbl(bm, pattern, len);
+	memcpy(bm->pattern, pattern, len);
+
+	return conf;
+}
+
+static void *bm_get_pattern(struct ts_config *conf)
+{
+	struct ts_bm *bm = ts_config_priv(conf);
+	return bm->pattern;
+}
+
+static unsigned int bm_get_pattern_len(struct ts_config *conf)
+{
+	struct ts_bm *bm = ts_config_priv(conf);
+	return bm->patlen;
+}
+
+static struct ts_ops bm_ops = {
+	.name		  = "bm",
+	.find		  = bm_find,
+	.init		  = bm_init,
+	.get_pattern	  = bm_get_pattern,
+	.get_pattern_len  = bm_get_pattern_len,
+	.owner		  = THIS_MODULE,
+	.list		  = LIST_HEAD_INIT(bm_ops.list)
+};
+
+static int __init init_bm(void)
+{
+	return textsearch_register(&bm_ops);
+}
+
+static void __exit exit_bm(void)
+{
+	textsearch_unregister(&bm_ops);
+}
--- /dev/null
+++ b/net/ipv4/netfilter/textsearch/ts_kmp.c
@@ -0,0 +1,141 @@
+/*
+ * lib/ts_kmp.c		Knuth-Morris-Pratt text search implementation
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Thomas Graf <tgraf@suug.ch>
+ *
+ * ==========================================================================
+ * 
+ *   Implements a linear-time string-matching algorithm due to Knuth,
+ *   Morris, and Pratt [1]. Their algorithm avoids the explicit
+ *   computation of the transition function DELTA altogether. Its
+ *   matching time is O(n), for n being length(text), using just an
+ *   auxiliary function PI[1..m], for m being length(pattern),
+ *   precomputed from the pattern in time O(m). The array PI allows
+ *   the transition function DELTA to be computed efficiently
+ *   "on the fly" as needed. Roughly speaking, for any state
+ *   "q" = 0,1,...,m and any character "a" in SIGMA, the value
+ *   PI["q"] contains the information that is independent of "a" and
+ *   is needed to compute DELTA("q", "a") [2]. Since the array PI
+ *   has only m entries, whereas DELTA has O(m|SIGMA|) entries, we
+ *   save a factor of |SIGMA| in the preprocessing time by computing
+ *   PI rather than DELTA.
+ *
+ *   [1] Cormen, Leiserson, Rivest, Stein
+ *       Introdcution to Algorithms, 2nd Edition, MIT Press
+ *   [2] See finite automation theory
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include "textsearch.h"
+
+struct ts_kmp
+{
+	u8 *		pattern;
+	unsigned int	pattern_len;
+	unsigned int 	prefix_tbl[0];
+};
+
+static unsigned int kmp_find(struct ts_config *conf, struct ts_state *state)
+{
+	struct ts_kmp *kmp = ts_config_priv(conf);
+	unsigned int i, q = 0, text_len, consumed = state->offset;
+	const u8 *text;
+
+	for (;;) {
+		text_len = conf->get_next_block(consumed, &text, conf, state);
+
+		if (unlikely(text_len == 0))
+			break;
+
+		for (i = 0; i < text_len; i++) {
+			while (q > 0 && kmp->pattern[q] != text[i])
+				q = kmp->prefix_tbl[q - 1];
+			if (kmp->pattern[q] == text[i])
+				q++;
+			if (unlikely(q == kmp->pattern_len)) {
+				state->offset = consumed + i + 1;
+				return state->offset - kmp->pattern_len;
+			}
+		}
+
+		consumed += text_len;
+	}
+
+	return UINT_MAX;
+}
+
+static inline void kmp_compute_prefix_tbl(const u8 *pattern, unsigned int len,
+				      unsigned int *prefix_tbl)
+{
+	unsigned int k, q;
+
+	for (k = 0, q = 1; q < len; q++) {
+		while (k > 0 && pattern[k] != pattern[q])
+			k = prefix_tbl[k-1];
+		if (pattern[k] == pattern[q])
+			k++;
+		prefix_tbl[q] = k;
+	}
+}
+
+static struct ts_config *kmp_init(const void *pattern, unsigned int len,
+				  gfp_t gfp_mask)
+{
+	struct ts_config *conf;
+	struct ts_kmp *kmp;
+	unsigned int prefix_tbl_len = len * sizeof(unsigned int);
+	size_t priv_size = sizeof(*kmp) + len + prefix_tbl_len;
+
+	conf = alloc_ts_config(priv_size, gfp_mask);
+	if (IS_ERR(conf))
+		return conf;
+
+	kmp = ts_config_priv(conf);
+	kmp->pattern_len = len;
+	kmp_compute_prefix_tbl(pattern, len, kmp->prefix_tbl);
+	kmp->pattern = (u8 *) kmp->prefix_tbl + prefix_tbl_len;
+	memcpy(kmp->pattern, pattern, len);
+
+	return conf;
+}
+
+static void *kmp_get_pattern(struct ts_config *conf)
+{
+	struct ts_kmp *kmp = ts_config_priv(conf);
+	return kmp->pattern;
+}
+
+static unsigned int kmp_get_pattern_len(struct ts_config *conf)
+{
+	struct ts_kmp *kmp = ts_config_priv(conf);
+	return kmp->pattern_len;
+}
+
+static struct ts_ops kmp_ops = {
+	.name		  = "kmp",
+	.find		  = kmp_find,
+	.init		  = kmp_init,
+	.get_pattern	  = kmp_get_pattern,
+	.get_pattern_len  = kmp_get_pattern_len,
+	.owner		  = THIS_MODULE,
+	.list		  = LIST_HEAD_INIT(kmp_ops.list)
+};
+
+static int __init init_kmp(void)
+{
+	return textsearch_register(&kmp_ops);
+}
+
+static void __exit exit_kmp(void)
+{
+	textsearch_unregister(&kmp_ops);
+}
+