diff options
Diffstat (limited to 'kernel/net/mac80211/michael.c')
| -rw-r--r-- | kernel/net/mac80211/michael.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/kernel/net/mac80211/michael.c b/kernel/net/mac80211/michael.c new file mode 100644 index 000000000..408649bd4 --- /dev/null +++ b/kernel/net/mac80211/michael.c @@ -0,0 +1,86 @@ +/* + * 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 <linux/bitops.h> +#include <linux/ieee80211.h> +#include <asm/unaligned.h> + +#include "michael.h" + +static void michael_block(struct michael_mic_ctx *mctx, u32 val) +{ + mctx->l ^= val; + mctx->r ^= rol32(mctx->l, 17); + mctx->l += mctx->r; + mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) | + ((mctx->l & 0x00ff00ff) << 8); + mctx->l += mctx->r; + mctx->r ^= rol32(mctx->l, 3); + mctx->l += mctx->r; + mctx->r ^= ror32(mctx->l, 2); + mctx->l += mctx->r; +} + +static void michael_mic_hdr(struct michael_mic_ctx *mctx, const u8 *key, + struct ieee80211_hdr *hdr) +{ + u8 *da, *sa, tid; + + da = ieee80211_get_DA(hdr); + sa = ieee80211_get_SA(hdr); + if (ieee80211_is_data_qos(hdr->frame_control)) + tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; + else + tid = 0; + + mctx->l = get_unaligned_le32(key); + mctx->r = get_unaligned_le32(key + 4); + + /* + * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC + * calculation, but it is _not_ transmitted + */ + michael_block(mctx, get_unaligned_le32(da)); + michael_block(mctx, get_unaligned_le16(&da[4]) | + (get_unaligned_le16(sa) << 16)); + michael_block(mctx, get_unaligned_le32(&sa[2])); + michael_block(mctx, tid); +} + +void michael_mic(const u8 *key, struct ieee80211_hdr *hdr, + const u8 *data, size_t data_len, u8 *mic) +{ + u32 val; + size_t block, blocks, left; + struct michael_mic_ctx mctx; + + michael_mic_hdr(&mctx, key, hdr); + + /* Real data */ + blocks = data_len / 4; + left = data_len % 4; + + for (block = 0; block < blocks; block++) + michael_block(&mctx, get_unaligned_le32(&data[block * 4])); + + /* 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]; + } + + michael_block(&mctx, val); + michael_block(&mctx, 0); + + put_unaligned_le32(mctx.l, mic); + put_unaligned_le32(mctx.r, mic + 4); +} |