add d80211 from a recent wireless-dev checkout

[openwrt/openwrt.git] / package / d80211 / src / michael.c

diff --git a/package/d80211/src/michael.c b/package/d80211/src/michael.c
new file mode 100644 (file)
index 0000000..0f844f7
--- /dev/null
+++ b/package/d80211/src/michael.c
@@ -0,0 +1,104 @@
+/*
+ * Michael MIC implementation - optimized for TKIP MIC operations
+ * Copyright 2002-2003, Instant802 Networks, Inc.
+ *
+ * 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/types.h>
+
+#include "michael.h"
+
+static inline u32 rotr(u32 val, int bits)
+{
+       return (val >> bits) | (val << (32 - bits));
+}
+
+
+static inline u32 rotl(u32 val, int bits)
+{
+       return (val << bits) | (val >> (32 - bits));
+}
+
+
+static inline u32 xswap(u32 val)
+{
+       return ((val & 0xff00ff00) >> 8) | ((val & 0x00ff00ff) << 8);
+}
+
+
+#define michael_block(l, r) \
+do { \
+       r ^= rotl(l, 17); \
+       l += r; \
+       r ^= xswap(l); \
+       l += r; \
+       r ^= rotl(l, 3); \
+       l += r; \
+       r ^= rotr(l, 2); \
+       l += r; \
+} while (0)
+
+
+static inline u32 michael_get32(u8 *data)
+{
+       return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+}
+
+
+static inline void michael_put32(u32 val, u8 *data)
+{
+       data[0] = val & 0xff;
+       data[1] = (val >> 8) & 0xff;
+       data[2] = (val >> 16) & 0xff;
+       data[3] = (val >> 24) & 0xff;
+}
+
+
+void michael_mic(u8 *key, u8 *da, u8 *sa, u8 priority,
+                u8 *data, size_t data_len, u8 *mic)
+{
+       u32 l, r, val;
+       size_t block, blocks, left;
+
+       l = michael_get32(key);
+       r = michael_get32(key + 4);
+
+       /* A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC
+        * calculation, but it is _not_ transmitted */
+       l ^= michael_get32(da);
+       michael_block(l, r);
+       l ^= da[4] | (da[5] << 8) | (sa[0] << 16) | (sa[1] << 24);
+       michael_block(l, r);
+       l ^= michael_get32(&sa[2]);
+       michael_block(l, r);
+       l ^= priority;
+       michael_block(l, r);
+
+       /* Real data */
+       blocks = data_len / 4;
+       left = data_len % 4;
+
+       for (block = 0; block < blocks; block++) {
+               l ^= michael_get32(&data[block * 4]);
+               michael_block(l, r);
+       }
+
+       /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make
+        * total length a multiple of 4. */
+       val = 0x5a;
+       while (left > 0) {
+               val <<= 8;
+               left--;
+               val |= data[blocks * 4 + left];
+       }
+       l ^= val;
+       michael_block(l, r);
+       /* last block is zero, so l ^ 0 = l */
+       michael_block(l, r);
+
+       michael_put32(l, mic);
+       michael_put32(r, mic + 4);
+}