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- /* 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 struct xt_match *match,
- const void *matchinfo,
- int offset,
- unsigned int protoff,
- int *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 int checkentry(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 0;
- if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
- return 0;
- if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
- 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(const struct xt_match *match, void *matchinfo)
- {
- textsearch_destroy(STRING_TEXT_PRIV(matchinfo)->config);
- }
- static struct xt_match xt_string_match[] = {
- {
- .name = "string",
- .family = AF_INET,
- .checkentry = checkentry,
- .match = match,
- .destroy = destroy,
- .matchsize = sizeof(struct xt_string_info),
- .me = THIS_MODULE
- },
- {
- .name = "string",
- .family = AF_INET6,
- .checkentry = checkentry,
- .match = match,
- .destroy = destroy,
- .matchsize = sizeof(struct xt_string_info),
- .me = THIS_MODULE
- },
- };
- static int __init xt_string_init(void)
- {
- return xt_register_matches(xt_string_match, ARRAY_SIZE(xt_string_match));
- }
- static void __exit xt_string_fini(void)
- {
- xt_unregister_matches(xt_string_match, ARRAY_SIZE(xt_string_match));
- }
- module_init(xt_string_init);
- module_exit(xt_string_fini);
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