diff options
Diffstat (limited to 'package/mac80211/src/net/mac80211/michael.c')
-rw-r--r-- | package/mac80211/src/net/mac80211/michael.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/package/mac80211/src/net/mac80211/michael.c b/package/mac80211/src/net/mac80211/michael.c new file mode 100644 index 0000000..0f844f7 --- /dev/null +++ b/package/mac80211/src/net/mac80211/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); +} |