1 files changed, 79 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_ttl.c b/net/ipv4/netfilter/ipt_ttl.c
new file mode 100644
index 00000000000..219aa9de88c
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_ttl.c
@@ -0,0 +1,79 @@
+/* IP tables module for matching the value of the TTL 
+ *
+ * ipt_ttl.c,v 1.5 2000/11/13 11:16:08 laforge Exp
+ *
+ * (C) 2000,2001 by Harald Welte <laforge@netfilter.org>
+ *
+ * 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/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/netfilter_ipv4/ipt_ttl.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("IP tables TTL matching 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)
+{
+	const struct ipt_ttl_info *info = matchinfo;
+
+	switch (info->mode) {
+		case IPT_TTL_EQ:
+			return (skb->nh.iph->ttl == info->ttl);
+			break;
+		case IPT_TTL_NE:
+			return (!(skb->nh.iph->ttl == info->ttl));
+			break;
+		case IPT_TTL_LT:
+			return (skb->nh.iph->ttl < info->ttl);
+			break;
+		case IPT_TTL_GT:
+			return (skb->nh.iph->ttl > info->ttl);
+			break;
+		default:
+			printk(KERN_WARNING "ipt_ttl: unknown mode %d\n", 
+				info->mode);
+			return 0;
+	}
+
+	return 0;
+}
+
+static int checkentry(const char *tablename, const struct ipt_ip *ip,
+		      void *matchinfo, unsigned int matchsize,
+		      unsigned int hook_mask)
+{
+	if (matchsize != IPT_ALIGN(sizeof(struct ipt_ttl_info)))
+		return 0;
+
+	return 1;
+}
+
+static struct ipt_match ttl_match = {
+	.name		= "ttl",
+	.match		= &match,
+	.checkentry	= &checkentry,
+	.me		= THIS_MODULE,
+};
+
+static int __init init(void)
+{
+	return ipt_register_match(&ttl_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&ttl_match);
+
+}
+
+module_init(init);
+module_exit(fini);