diff --git a/include/net/checksum.h b/include/net/checksum.h
new file mode 100644
index 0000000..e3ea7cc
--- /dev/null
+++ b/include/net/checksum.h
@@ -0,0 +1,87 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Checksumming functions for IP, TCP, UDP and so on
+ *
+ * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
+ *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
+ *		Borrows very liberally from tcp.c and ip.c, see those
+ *		files for more names.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _CHECKSUM_H
+#define _CHECKSUM_H
+
+#include <linux/errno.h>
+#include <asm/types.h>
+#include <asm/byteorder.h>
+#include <asm/uaccess.h>
+#include <asm/checksum.h>
+
+#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+static inline
+unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst,
+				      int len, int sum, int *err_ptr)
+{
+	if (access_ok(VERIFY_READ, src, len))
+		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
+
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return sum;
+}
+#endif
+
+#ifndef HAVE_CSUM_COPY_USER
+static __inline__ unsigned int csum_and_copy_to_user
+(const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr)
+{
+	sum = csum_partial(src, len, sum);
+
+	if (access_ok(VERIFY_WRITE, dst, len)) {
+		if (copy_to_user(dst, src, len) == 0)
+			return sum;
+	}
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return -1; /* invalid checksum */
+}
+#endif
+
+static inline unsigned int csum_add(unsigned int csum, unsigned int addend)
+{
+	csum += addend;
+	return csum + (csum < addend);
+}
+
+static inline unsigned int csum_sub(unsigned int csum, unsigned int addend)
+{
+	return csum_add(csum, ~addend);
+}
+
+static inline unsigned int
+csum_block_add(unsigned int csum, unsigned int csum2, int offset)
+{
+	if (offset&1)
+		csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
+	return csum_add(csum, csum2);
+}
+
+static inline unsigned int
+csum_block_sub(unsigned int csum, unsigned int csum2, int offset)
+{
+	if (offset&1)
+		csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
+	return csum_sub(csum, csum2);
+}
+
+#endif