patch-2.4.14 linux/net/ipv4/netfilter/ipt_ttl.c

• Lines: 76
• Date: Tue Oct 30 15:08:12 2001
• Orig file: v2.4.13/linux/net/ipv4/netfilter/ipt_ttl.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.13/linux/net/ipv4/netfilter/ipt_ttl.c linux/net/ipv4/netfilter/ipt_ttl.c
@@ -0,0 +1,75 @@
+/* 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@gnumonks.org>
+ *
+ * This software is distributed under the terms  GNU GPL
+ */
+
+#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@gnumonks.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, const void *hdr, u_int16_t datalen,
+		 int *hotdrop)
+{
+	const struct ipt_ttl_info *info = matchinfo;
+	const struct iphdr *iph = skb->nh.iph;
+
+	switch (info->mode) {
+		case IPT_TTL_EQ:
+			return (iph->ttl == info->ttl);
+			break;
+		case IPT_TTL_NE:
+			return (!(iph->ttl == info->ttl));
+			break;
+		case IPT_TTL_LT:
+			return (iph->ttl < info->ttl);
+			break;
+		case IPT_TTL_GT:
+			return (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 = { { NULL, NULL }, "ttl", &match,
+		&checkentry, NULL, 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);