diff options
Diffstat (limited to 'net/netfilter/xt_string.c')
-rw-r--r-- | net/netfilter/xt_string.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/net/netfilter/xt_string.c b/net/netfilter/xt_string.c new file mode 100644 index 000000000000..7c7d5c8807d6 --- /dev/null +++ b/net/netfilter/xt_string.c @@ -0,0 +1,111 @@ +/* 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); |