[NETFILTER]: Add string match
Signed-off-by: Pablo Neira Ayuso <pablo@eurodev.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/ipt_string.c b/net/ipv4/netfilter/ipt_string.c
new file mode 100644
index 0000000..b5def20
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_string.c
@@ -0,0 +1,91 @@
+/* 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 <linux/textsearch.h>
+
+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 ts_state state;
+ struct ipt_string_info *conf = (struct ipt_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 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)
+{
+ return ipt_register_match(&string_match);
+}
+
+static void __exit fini(void)
+{
+ ipt_unregister_match(&string_match);
+}
+
+module_init(init);
+module_exit(fini);