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yaml
---
r: 102736
b: refs/heads/master
c: 1b19ca3
h: refs/heads/master
v: v3
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Harvey Harrison authored and John W. Linville committed May 22, 2008
1 parent a5cc6e0 commit 6543e26
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Showing 3 changed files with 45 additions and 36 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 1bd3dff549537d3d9b92d0b284f4cc2be264a56d
refs/heads/master: 1b19ca396621dcba573b20d4625526f5a460c886
75 changes: 40 additions & 35 deletions trunk/net/mac80211/michael.c
Original file line number Diff line number Diff line change
Expand Up @@ -13,46 +13,52 @@

#include "michael.h"

#define michael_block(l, r) \
do { \
r ^= rol32(l, 17); \
l += r; \
r ^= ((l & 0xff00ff00) >> 8) | ((l & 0x00ff00ff) << 8); \
l += r; \
r ^= rol32(l, 3); \
l += r; \
r ^= ror32(l, 2); \
l += r; \
} while (0)
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,
u8 *key, u8 *da, u8 *sa, u8 priority)
{
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, priority);
}

void michael_mic(u8 *key, u8 *da, u8 *sa, u8 priority,
u8 *data, size_t data_len, u8 *mic)
{
u32 l, r, val;
u32 val;
size_t block, blocks, left;
struct michael_mic_ctx mctx;

l = get_unaligned_le32(key);
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 */
l ^= get_unaligned_le32(da);
michael_block(l, r);
l ^= get_unaligned_le16(&da[4]) | (get_unaligned_le16(sa) << 16);
michael_block(l, r);
l ^= get_unaligned_le32(&sa[2]);
michael_block(l, r);
l ^= priority;
michael_block(l, r);
michael_mic_hdr(&mctx, key, da, sa, priority);

/* Real data */
blocks = data_len / 4;
left = data_len % 4;

for (block = 0; block < blocks; block++) {
l ^= get_unaligned_le32(&data[block * 4]);
michael_block(l, r);
}
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. */
Expand All @@ -62,11 +68,10 @@ void michael_mic(u8 *key, u8 *da, u8 *sa, u8 priority,
left--;
val |= data[blocks * 4 + left];
}
l ^= val;
michael_block(l, r);
/* last block is zero, so l ^ 0 = l */
michael_block(l, r);

put_unaligned_le32(l, mic);
put_unaligned_le32(r, mic + 4);
michael_block(&mctx, val);
michael_block(&mctx, 0);

put_unaligned_le32(mctx.l, mic);
put_unaligned_le32(mctx.r, mic + 4);
}
4 changes: 4 additions & 0 deletions trunk/net/mac80211/michael.h
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,10 @@

#define MICHAEL_MIC_LEN 8

struct michael_mic_ctx {
u32 l, r;
};

void michael_mic(u8 *key, u8 *da, u8 *sa, u8 priority,
u8 *data, size_t data_len, u8 *mic);

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