/* 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/x_tables.h>#include <linux/netfilter/xt_string.h>#include <linux/textsearch.h> MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");MODULE_DESCRIPTION("IP tables string match module");MODULE_LICENSE("GPL");MODULE_ALIAS("ipt_string");MODULE_ALIAS("ip6t_string"); static int match(const struct sk_buff *skb,		 const struct net_device *in,		 const struct net_device *out,		 const void *matchinfo,		 int offset,		 unsigned int protoff,		 int *hotdrop){	struct ts_state state;	struct xt_string_info *conf = (struct xt_string_info *) matchinfo; 	memset(&state, 0, sizeof(struct ts_state)); 	return (skb_find_text((struct sk_buff *)skb, conf->from_offset, 			     conf->to_offset, conf->config, &state) 			     != UINT_MAX) && !conf->invert;} #define STRING_TEXT_PRIV(m) ((struct xt_string_info *) m) static int checkentry(const char *tablename,		      const void *ip,		      void *matchinfo,		      unsigned int matchsize,		      unsigned int hook_mask){	struct xt_string_info *conf = matchinfo;	struct ts_config *ts_conf; 	if (matchsize != XT_ALIGN(sizeof(struct xt_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 xt_match string_match = {	.name 		= "string",	.match 		= match,	.checkentry	= checkentry,	.destroy 	= destroy,	.me 		= THIS_MODULE};static struct xt_match string6_match = {	.name 		= "string",	.match 		= match,	.checkentry	= checkentry,	.destroy 	= destroy,	.me 		= THIS_MODULE}; static int __init init(void){	int ret; 	ret = xt_register_match(AF_INET, &string_match);	if (ret)		return ret;	ret = xt_register_match(AF_INET6, &string6_match);	if (ret)		xt_unregister_match(AF_INET, &string_match); 	return ret;} static void __exit fini(void){	xt_unregister_match(AF_INET, &string_match);	xt_unregister_match(AF_INET6, &string6_match);} module_init(init);module_exit(fini);