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Commit | Line | Data |
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f0706e82 JB |
1 | /* |
2 | * Michael MIC implementation - optimized for TKIP MIC operations | |
3 | * Copyright 2002-2003, Instant802 Networks, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
f0706e82 | 9 | #include <linux/types.h> |
1bd3dff5 HH |
10 | #include <linux/bitops.h> |
11 | #include <asm/unaligned.h> | |
f0706e82 JB |
12 | |
13 | #include "michael.h" | |
14 | ||
1b19ca39 HH |
15 | static void michael_block(struct michael_mic_ctx *mctx, u32 val) |
16 | { | |
17 | mctx->l ^= val; | |
18 | mctx->r ^= rol32(mctx->l, 17); | |
19 | mctx->l += mctx->r; | |
20 | mctx->r ^= ((mctx->l & 0xff00ff00) >> 8) | | |
21 | ((mctx->l & 0x00ff00ff) << 8); | |
22 | mctx->l += mctx->r; | |
23 | mctx->r ^= rol32(mctx->l, 3); | |
24 | mctx->l += mctx->r; | |
25 | mctx->r ^= ror32(mctx->l, 2); | |
26 | mctx->l += mctx->r; | |
27 | } | |
28 | ||
29 | static void michael_mic_hdr(struct michael_mic_ctx *mctx, | |
a7b6f0c5 | 30 | const u8 *key, const u8 *da, const u8 *sa, u8 priority) |
1b19ca39 HH |
31 | { |
32 | mctx->l = get_unaligned_le32(key); | |
33 | mctx->r = get_unaligned_le32(key + 4); | |
34 | ||
35 | /* | |
36 | * A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC | |
37 | * calculation, but it is _not_ transmitted | |
38 | */ | |
39 | michael_block(mctx, get_unaligned_le32(da)); | |
40 | michael_block(mctx, get_unaligned_le16(&da[4]) | | |
41 | (get_unaligned_le16(sa) << 16)); | |
42 | michael_block(mctx, get_unaligned_le32(&sa[2])); | |
43 | michael_block(mctx, priority); | |
44 | } | |
f0706e82 | 45 | |
a7b6f0c5 HH |
46 | void michael_mic(const u8 *key, const u8 *da, const u8 *sa, u8 priority, |
47 | const u8 *data, size_t data_len, u8 *mic) | |
f0706e82 | 48 | { |
1b19ca39 | 49 | u32 val; |
f0706e82 | 50 | size_t block, blocks, left; |
1b19ca39 | 51 | struct michael_mic_ctx mctx; |
f0706e82 | 52 | |
1b19ca39 | 53 | michael_mic_hdr(&mctx, key, da, sa, priority); |
f0706e82 JB |
54 | |
55 | /* Real data */ | |
56 | blocks = data_len / 4; | |
57 | left = data_len % 4; | |
58 | ||
1b19ca39 HH |
59 | for (block = 0; block < blocks; block++) |
60 | michael_block(&mctx, get_unaligned_le32(&data[block * 4])); | |
f0706e82 JB |
61 | |
62 | /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make | |
63 | * total length a multiple of 4. */ | |
64 | val = 0x5a; | |
65 | while (left > 0) { | |
66 | val <<= 8; | |
67 | left--; | |
68 | val |= data[blocks * 4 + left]; | |
69 | } | |
f0706e82 | 70 | |
1b19ca39 HH |
71 | michael_block(&mctx, val); |
72 | michael_block(&mctx, 0); | |
73 | ||
74 | put_unaligned_le32(mctx.l, mic); | |
75 | put_unaligned_le32(mctx.r, mic + 4); | |
f0706e82 | 76 | } |