mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-11-09 16:06:15 +02:00
261aac9420
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@5939 3c298f89-4303-0410-b956-a3cf2f4a3e73
105 lines
2.1 KiB
C
105 lines
2.1 KiB
C
/*
|
|
* 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);
|
|
}
|