[CRYPTO] lib: some common 128-bit block operations, nicely centralized

128bit is a common blocksize in linux kernel cryptography, so it helps to
centralize some common operations.

The code, while mostly trivial, is based on a header file mode_hdr.h in
http://fp.gladman.plus.com/AES/modes.vc8.19-06-06.zip

The original copyright (and GPL statement) of the original author,
Dr Brian Gladman, is preserved.
Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/b128ops.h

+/* b128ops.h - common 128-bit block operations
+ *
+ * Copyright (c) 2003, Dr Brian Gladman, Worcester, UK.
+ * Copyright (c) 2006, Rik Snel <rsnel@cube.dyndns.org>
+ *
+ * Based on Dr Brian Gladman's (GPL'd) work published at
+ * http://fp.gladman.plus.com/cryptography_technology/index.htm
+ * See the original copyright notice below.
+ *
+ * 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.
+ */
+/*
+ ---------------------------------------------------------------------------
+ Copyright (c) 2003, Dr Brian Gladman, Worcester, UK.   All rights reserved.
+
+ LICENSE TERMS
+
+ The free distribution and use of this software in both source and binary
+ form is allowed (with or without changes) provided that:
+
+   1. distributions of this source code include the above copyright
+      notice, this list of conditions and the following disclaimer;
+
+   2. distributions in binary form include the above copyright
+      notice, this list of conditions and the following disclaimer
+      in the documentation and/or other associated materials;
+
+   3. the copyright holder's name is not used to endorse products
+      built using this software without specific written permission.
+
+ ALTERNATIVELY, provided that this notice is retained in full, this product
+ may be distributed under the terms of the GNU General Public License (GPL),
+ in which case the provisions of the GPL apply INSTEAD OF those given above.
+
+ DISCLAIMER
+
+ This software is provided 'as is' with no explicit or implied warranties
+ in respect of its properties, including, but not limited to, correctness
+ and/or fitness for purpose.
+ ---------------------------------------------------------------------------
+ Issue Date: 13/06/2006
+*/
+
+#ifndef _CRYPTO_B128OPS_H
+#define _CRYPTO_B128OPS_H
+
+#include <linux/types.h>
+
+typedef struct {
+	u64 a, b;
+} u128;
+
+typedef struct {
+	__be64 a, b;
+} be128;
+
+typedef struct {
+	__le64 b, a;
+} le128;
+
+static inline void u128_xor(u128 *r, const u128 *p, const u128 *q)
+{
+	r->a = p->a ^ q->a;
+	r->b = p->b ^ q->b;
+}
+
+static inline void be128_xor(be128 *r, const be128 *p, const be128 *q)
+{
+	u128_xor((u128 *)r, (u128 *)p, (u128 *)q);
+}
+
+static inline void le128_xor(le128 *r, const le128 *p, const le128 *q)
+{
+	u128_xor((u128 *)r, (u128 *)p, (u128 *)q);
+}
+
+#endif /* _CRYPTO_B128OPS_H */