1 files changed, 64 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_length.c b/net/ipv4/netfilter/ipt_length.c
new file mode 100644
index 000000000000..4eabcfbda9d1
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_length.c
@@ -0,0 +1,64 @@
+/* Kernel module to match packet length. */
+/* (C) 1999-2001 James Morris <jmorros@intercode.com.au>
+ *
+ * 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_length.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
+MODULE_DESCRIPTION("IP tables packet length 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_length_info *info = matchinfo;
+	u_int16_t pktlen = ntohs(skb->nh.iph->tot_len);
+	
+	return (pktlen >= info->min && pktlen <= info->max) ^ info->invert;
+}
+
+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_length_info)))
+		return 0;
+
+	return 1;
+}
+
+static struct ipt_match length_match = {
+	.name		= "length",
+	.match		= &match,
+	.checkentry	= &checkentry,
+	.me		= THIS_MODULE,
+};
+
+static int __init init(void)
+{
+	return ipt_register_match(&length_match);
+}
+
+static void __exit fini(void)
+{
+	ipt_unregister_match(&length_match);
+}
+
+module_init(init);
+module_exit(fini);