/* 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("Xtables: string-based matching");MODULE_LICENSE("GPL");MODULE_ALIAS("ipt_string");MODULE_ALIAS("ip6t_string"); static boolstring_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,          bool *hotdrop){	const struct xt_string_info *conf = matchinfo;	struct ts_state state; 	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 boolstring_mt_check(const char *tablename, const void *ip,                const struct xt_match *match, void *matchinfo,                unsigned int hook_mask){	struct xt_string_info *conf = matchinfo;	struct ts_config *ts_conf; 	/* Damn, can't handle this case properly with iptables... */	if (conf->from_offset > conf->to_offset)		return false;	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')		return false;	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)		return false;	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,				     GFP_KERNEL, TS_AUTOLOAD);	if (IS_ERR(ts_conf))		return false; 	conf->config = ts_conf; 	return true;} static void string_mt_destroy(const struct xt_match *match, void *matchinfo){	textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);} static struct xt_match string_mt_reg[] __read_mostly = {	{		.name 		= "string",		.family		= AF_INET,		.checkentry	= string_mt_check,		.match 		= string_mt,		.destroy 	= string_mt_destroy,		.matchsize	= sizeof(struct xt_string_info),		.me 		= THIS_MODULE	},	{		.name 		= "string",		.family		= AF_INET6,		.checkentry	= string_mt_check,		.match 		= string_mt,		.destroy 	= string_mt_destroy,		.matchsize	= sizeof(struct xt_string_info),		.me 		= THIS_MODULE	},}; static int __init string_mt_init(void){	return xt_register_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg));} static void __exit string_mt_exit(void){	xt_unregister_matches(string_mt_reg, ARRAY_SIZE(string_mt_reg));} module_init(string_mt_init);module_exit(string_mt_exit);