add git checkout support
[openwrt/openwrt.git] / package / mac80211 / src / mac80211 / michael.c
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 */
9
10 #include <linux/types.h>
11
12 #include "michael.h"
13
14 static inline u32 rotr(u32 val, int bits)
15 {
16 return (val >> bits) | (val << (32 - bits));
17 }
18
19
20 static inline u32 rotl(u32 val, int bits)
21 {
22 return (val << bits) | (val >> (32 - bits));
23 }
24
25
26 static inline u32 xswap(u32 val)
27 {
28 return ((val & 0xff00ff00) >> 8) | ((val & 0x00ff00ff) << 8);
29 }
30
31
32 #define michael_block(l, r) \
33 do { \
34 r ^= rotl(l, 17); \
35 l += r; \
36 r ^= xswap(l); \
37 l += r; \
38 r ^= rotl(l, 3); \
39 l += r; \
40 r ^= rotr(l, 2); \
41 l += r; \
42 } while (0)
43
44
45 static inline u32 michael_get32(u8 *data)
46 {
47 return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
48 }
49
50
51 static inline void michael_put32(u32 val, u8 *data)
52 {
53 data[0] = val & 0xff;
54 data[1] = (val >> 8) & 0xff;
55 data[2] = (val >> 16) & 0xff;
56 data[3] = (val >> 24) & 0xff;
57 }
58
59
60 void michael_mic(u8 *key, u8 *da, u8 *sa, u8 priority,
61 u8 *data, size_t data_len, u8 *mic)
62 {
63 u32 l, r, val;
64 size_t block, blocks, left;
65
66 l = michael_get32(key);
67 r = michael_get32(key + 4);
68
69 /* A pseudo header (DA, SA, Priority, 0, 0, 0) is used in Michael MIC
70 * calculation, but it is _not_ transmitted */
71 l ^= michael_get32(da);
72 michael_block(l, r);
73 l ^= da[4] | (da[5] << 8) | (sa[0] << 16) | (sa[1] << 24);
74 michael_block(l, r);
75 l ^= michael_get32(&sa[2]);
76 michael_block(l, r);
77 l ^= priority;
78 michael_block(l, r);
79
80 /* Real data */
81 blocks = data_len / 4;
82 left = data_len % 4;
83
84 for (block = 0; block < blocks; block++) {
85 l ^= michael_get32(&data[block * 4]);
86 michael_block(l, r);
87 }
88
89 /* Partial block of 0..3 bytes and padding: 0x5a + 4..7 zeros to make
90 * total length a multiple of 4. */
91 val = 0x5a;
92 while (left > 0) {
93 val <<= 8;
94 left--;
95 val |= data[blocks * 4 + left];
96 }
97 l ^= val;
98 michael_block(l, r);
99 /* last block is zero, so l ^ 0 = l */
100 michael_block(l, r);
101
102 michael_put32(l, mic);
103 michael_put32(r, mic + 4);
104 }