blob: 1fcdf38cf60c1957f1d5faa7c8175150257ad886 [file] [log] [blame]
Jiri Bencf0706e82007-05-05 11:45:53 -07001/*
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 */
Jiri Bencf0706e82007-05-05 11:45:53 -07009#include <linux/types.h>
Harvey Harrison1bd3dff2008-05-14 16:26:16 -070010#include <linux/bitops.h>
11#include <asm/unaligned.h>
Jiri Bencf0706e82007-05-05 11:45:53 -070012
13#include "michael.h"
14
Harvey Harrison1b19ca32008-05-14 16:26:17 -070015static 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
29static void michael_mic_hdr(struct michael_mic_ctx *mctx,
Harvey Harrisona7b6f0c2008-05-14 16:26:18 -070030 const u8 *key, const u8 *da, const u8 *sa, u8 priority)
Harvey Harrison1b19ca32008-05-14 16:26:17 -070031{
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}
Jiri Bencf0706e82007-05-05 11:45:53 -070045
Harvey Harrisona7b6f0c2008-05-14 16:26:18 -070046void michael_mic(const u8 *key, const u8 *da, const u8 *sa, u8 priority,
47 const u8 *data, size_t data_len, u8 *mic)
Jiri Bencf0706e82007-05-05 11:45:53 -070048{
Harvey Harrison1b19ca32008-05-14 16:26:17 -070049 u32 val;
Jiri Bencf0706e82007-05-05 11:45:53 -070050 size_t block, blocks, left;
Harvey Harrison1b19ca32008-05-14 16:26:17 -070051 struct michael_mic_ctx mctx;
Jiri Bencf0706e82007-05-05 11:45:53 -070052
Harvey Harrison1b19ca32008-05-14 16:26:17 -070053 michael_mic_hdr(&mctx, key, da, sa, priority);
Jiri Bencf0706e82007-05-05 11:45:53 -070054
55 /* Real data */
56 blocks = data_len / 4;
57 left = data_len % 4;
58
Harvey Harrison1b19ca32008-05-14 16:26:17 -070059 for (block = 0; block < blocks; block++)
60 michael_block(&mctx, get_unaligned_le32(&data[block * 4]));
Jiri Bencf0706e82007-05-05 11:45:53 -070061
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 }
Jiri Bencf0706e82007-05-05 11:45:53 -070070
Harvey Harrison1b19ca32008-05-14 16:26:17 -070071 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);
Jiri Bencf0706e82007-05-05 11:45:53 -070076}