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authorFelix Fietkau <nbd@openwrt.org>2006-11-14 01:45:10 +0000
committerFelix Fietkau <nbd@openwrt.org>2006-11-14 01:45:10 +0000
commitbffe7837e75c6f8f2178e406e5432fe2c6e1e572 (patch)
tree05454cf2f33c1ab8bcd0ba09e0738b5b4d83ef85 /target/linux
parentb2dedf0ab273bac41f1d19c786e73a385451c0fd (diff)
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fix the backport of ipt_string by adding the linux 2.6 textsearch code in a way that does not require adding stuff to our kernel image - linux 2.6 compatible
SVN-Revision: 5527
Diffstat (limited to 'target/linux')
-rw-r--r--target/linux/generic-2.4/patches/609-netfilter_string.patch867
1 files changed, 750 insertions, 117 deletions
diff --git a/target/linux/generic-2.4/patches/609-netfilter_string.patch b/target/linux/generic-2.4/patches/609-netfilter_string.patch
index c8e1a2d2de..ed5353f7a9 100644
--- a/target/linux/generic-2.4/patches/609-netfilter_string.patch
+++ b/target/linux/generic-2.4/patches/609-netfilter_string.patch
@@ -1,6 +1,6 @@
-diff -Nur linux-2.4.32/include/linux/netfilter_ipv4/ipt_string.h linux-2.4.32.patch/include/linux/netfilter_ipv4/ipt_string.h
---- linux-2.4.32/include/linux/netfilter_ipv4/ipt_string.h 1970-01-01 01:00:00.000000000 +0100
-+++ linux-2.4.32.patch/include/linux/netfilter_ipv4/ipt_string.h 2005-12-16 00:40:19.082509250 +0100
+diff -urN linux.old/include/linux/netfilter_ipv4/ipt_string.h linux.dev/include/linux/netfilter_ipv4/ipt_string.h
+--- linux.old/include/linux/netfilter_ipv4/ipt_string.h 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/include/linux/netfilter_ipv4/ipt_string.h 2006-11-13 23:33:31.000000000 +0100
@@ -0,0 +1,18 @@
+#ifndef _IPT_STRING_H
+#define _IPT_STRING_H
@@ -20,10 +20,444 @@ diff -Nur linux-2.4.32/include/linux/netfilter_ipv4/ipt_string.h linux-2.4.32.pa
+};
+
+#endif /*_IPT_STRING_H*/
-diff -Nur linux-2.4.32/include/linux/textsearch.h linux-2.4.32.patch/include/linux/textsearch.h
---- linux-2.4.32/include/linux/textsearch.h 1970-01-01 01:00:00.000000000 +0100
-+++ linux-2.4.32.patch/include/linux/textsearch.h 2005-12-16 11:15:34.838073000 +0100
-@@ -0,0 +1,205 @@
+diff -urN linux.old/net/ipv4/netfilter/Config.in linux.dev/net/ipv4/netfilter/Config.in
+--- linux.old/net/ipv4/netfilter/Config.in 2006-11-13 23:43:38.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/Config.in 2006-11-13 23:33:31.000000000 +0100
+@@ -52,6 +52,7 @@
+ 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
+diff -urN linux.old/net/ipv4/netfilter/ipt_string.c linux.dev/net/ipv4/netfilter/ipt_string.c
+--- linux.old/net/ipv4/netfilter/ipt_string.c 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/ipt_string.c 2006-11-14 02:26:03.000000000 +0100
+@@ -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);
+diff -urN linux.old/net/ipv4/netfilter/Makefile linux.dev/net/ipv4/netfilter/Makefile
+--- linux.old/net/ipv4/netfilter/Makefile 2006-11-13 23:43:38.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/Makefile 2006-11-13 23:33:31.000000000 +0100
+@@ -107,6 +107,7 @@
+ 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-$(CONFIG_IP_NF_MATCH_LAYER7) += ipt_layer7.o
+ obj-$(CONFIG_IP_NF_MATCH_CONNBYTES) += ipt_connbytes.o
+diff -urN linux.old/net/ipv4/netfilter/textsearch/textsearch.c linux.dev/net/ipv4/netfilter/textsearch/textsearch.c
+--- linux.old/net/ipv4/netfilter/textsearch/textsearch.c 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/textsearch/textsearch.c 2006-11-14 02:31:47.000000000 +0100
+@@ -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);
++}
++
+diff -urN linux.old/net/ipv4/netfilter/textsearch/textsearch.h linux.dev/net/ipv4/netfilter/textsearch/textsearch.h
+--- linux.old/net/ipv4/netfilter/textsearch/textsearch.h 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/textsearch/textsearch.h 2006-11-14 02:11:59.000000000 +0100
+@@ -0,0 +1,182 @@
+#ifndef __LINUX_TEXTSEARCH_H
+#define __LINUX_TEXTSEARCH_H
+
@@ -35,30 +469,7 @@ diff -Nur linux-2.4.32/include/linux/textsearch.h linux-2.4.32.patch/include/lin
+#include <linux/module.h>
+#include <linux/slab.h>
+
-+#ifdef __CHECKER__
-+#define __bitwise__ __attribute__((bitwise))
-+#else
-+#define __bitwise__
-+#endif
-+#ifdef __CHECK_ENDIAN__
-+#define __bitwise __bitwise__
-+#else
-+#define __bitwise
-+#endif
-+
-+typedef __u16 __bitwise __le16;
-+typedef __u16 __bitwise __be16;
-+typedef __u32 __bitwise __le32;
-+typedef __u32 __bitwise __be32;
-+#if defined(__GNUC__) && !defined(__STRICT_ANSI__)
-+typedef __u64 __bitwise __le64;
-+typedef __u64 __bitwise __be64;
-+#endif
-+
-+#ifdef __KERNEL__
-+typedef unsigned __bitwise__ gfp_t;
-+#endif
-+
++typedef int gfp_t;
+struct ts_config;
+
+/**
@@ -215,7 +626,7 @@ diff -Nur linux-2.4.32/include/linux/textsearch.h linux-2.4.32.patch/include/lin
+
+ conf = kmalloc(TS_PRIV_ALIGN(sizeof(*conf)) + payload, gfp_mask);
+ if (conf == NULL)
-+ return -ENOMEM;
++ return ERR_PTR(-ENOMEM);
+
+ memset(conf, 0, TS_PRIV_ALIGN(sizeof(*conf)) + payload);
+ return conf;
@@ -229,120 +640,342 @@ diff -Nur linux-2.4.32/include/linux/textsearch.h linux-2.4.32.patch/include/lin
+#endif /* __KERNEL__ */
+
+#endif
-diff -Nur linux-2.4.32/net/ipv4/netfilter/Config.in linux-2.4.32.patch/net/ipv4/netfilter/Config.in
---- linux-2.4.32/net/ipv4/netfilter/Config.in 2005-01-19 15:10:13.000000000 +0100
-+++ linux-2.4.32.patch/net/ipv4/netfilter/Config.in 2005-12-16 00:41:43.023755250 +0100
-@@ -42,6 +42,7 @@
- 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
- fi
- # The targets
-diff -Nur linux-2.4.32/net/ipv4/netfilter/ipt_string.c linux-2.4.32.patch/net/ipv4/netfilter/ipt_string.c
---- linux-2.4.32/net/ipv4/netfilter/ipt_string.c 1970-01-01 01:00:00.000000000 +0100
-+++ linux-2.4.32.patch/net/ipv4/netfilter/ipt_string.c 2005-12-16 00:40:48.436343750 +0100
-@@ -0,0 +1,91 @@
-+/* String matching match for iptables
+diff -urN linux.old/net/ipv4/netfilter/textsearch/ts_bm.c linux.dev/net/ipv4/netfilter/textsearch/ts_bm.c
+--- linux.old/net/ipv4/netfilter/textsearch/ts_bm.c 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/textsearch/ts_bm.c 2006-11-14 02:22:20.000000000 +0100
+@@ -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>
++ *
++ * ==========================================================================
+ *
-+ * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
++ * Implements Boyer-Moore string matching algorithm:
+ *
-+ * 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.
++ * [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/init.h>
-+#include <linux/module.h>
++#include <linux/config.h>
+#include <linux/kernel.h>
-+#include <linux/skbuff.h>
-+#include <linux/netfilter_ipv4/ip_tables.h>
-+#include <linux/netfilter_ipv4/ipt_string.h>
-+#include <linux/textsearch.h>
++#include <linux/module.h>
++#include <linux/types.h>
++#include <linux/string.h>
++#include "textsearch.h"
+
-+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
-+MODULE_DESCRIPTION("IP tables string match module");
-+MODULE_LICENSE("GPL");
++/* Alphabet size, use ASCII */
++#define ASIZE 256
+
-+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)
++#if 0
++#define DEBUGP printk
++#else
++#define DEBUGP(args, format...)
++#endif
++
++struct ts_bm
+{
-+ struct ts_state state;
-+ struct ipt_string_info *conf = (struct ipt_string_info *) matchinfo;
++ u8 * pattern;
++ unsigned int patlen;
++ unsigned int bad_shift[ASIZE];
++ unsigned int good_shift[0];
++};
+
-+ memset(&state, 0, sizeof(struct ts_state));
++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;
+
-+ return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
-+ conf->to_offset, conf->config, &state)
-+ != UINT_MAX) && !conf->invert;
++ /* 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;
+}
+
-+#define STRING_TEXT_PRIV(m) ((struct ipt_string_info *) m)
++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;
++ }
++ }
+
-+static int checkentry(const char *tablename,
-+ const struct ipt_ip *ip,
-+ void *matchinfo,
-+ unsigned int matchsize,
-+ unsigned int hook_mask)
++ return ret;
++}
++
++static void bm_compute_prefix_tbl(struct ts_bm *bm, const u8 *pattern,
++ unsigned int len)
+{
-+ struct ipt_string_info *conf = matchinfo;
-+ struct ts_config *ts_conf;
++ 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;
++ }
++ }
++}
+
-+ if (matchsize != IPT_ALIGN(sizeof(struct ipt_string_info)))
-+ return 0;
++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;
+
-+ /* Damn, can't handle this case properly with iptables... */
-+ if (conf->from_offset > conf->to_offset)
-+ return 0;
++ conf = alloc_ts_config(priv_size, gfp_mask);
++ if (IS_ERR(conf))
++ return conf;
+
-+ ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
-+ GFP_KERNEL, TS_AUTOLOAD);
-+ if (IS_ERR(ts_conf))
-+ return 0;
++ 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);
+
-+ conf->config = ts_conf;
++ return conf;
++}
+
-+ return 1;
++static void *bm_get_pattern(struct ts_config *conf)
++{
++ struct ts_bm *bm = ts_config_priv(conf);
++ return bm->pattern;
+}
+
-+static void destroy(void *matchinfo, unsigned int matchsize)
++static unsigned int bm_get_pattern_len(struct ts_config *conf)
+{
-+ textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
++ struct ts_bm *bm = ts_config_priv(conf);
++ return bm->patlen;
+}
+
-+static struct ipt_match string_match = {
-+ .name = "string",
-+ .match = match,
-+ .checkentry = checkentry,
-+ .destroy = destroy,
-+ .me = THIS_MODULE
++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(void)
++static int __init init_bm(void)
+{
-+ return ipt_register_match(&string_match);
++ return textsearch_register(&bm_ops);
+}
+
-+static void __exit fini(void)
++static void __exit exit_bm(void)
+{
-+ ipt_unregister_match(&string_match);
++ textsearch_unregister(&bm_ops);
++}
+diff -urN linux.old/net/ipv4/netfilter/textsearch/ts_kmp.c linux.dev/net/ipv4/netfilter/textsearch/ts_kmp.c
+--- linux.old/net/ipv4/netfilter/textsearch/ts_kmp.c 1970-01-01 01:00:00.000000000 +0100
++++ linux.dev/net/ipv4/netfilter/textsearch/ts_kmp.c 2006-11-14 02:22:04.000000000 +0100
+@@ -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);
+}
+
-+module_init(init);
-+module_exit(fini);
-diff -Nur linux-2.4.32/net/ipv4/netfilter/Makefile linux-2.4.32.patch/net/ipv4/netfilter/Makefile
---- linux-2.4.32/net/ipv4/netfilter/Makefile 2003-08-25 13:44:44.000000000 +0200
-+++ linux-2.4.32.patch/net/ipv4/netfilter/Makefile 2005-12-16 00:42:10.929499250 +0100
-@@ -85,6 +85,7 @@
- obj-$(CONFIG_IP_NF_MATCH_STATE) += ipt_state.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
-
- # targets