linux-imx

/*

 * Cryptographic API

 *

 * Michael MIC (IEEE 802.11i/TKIP) keyed digest

 *

 * Copyright (c) 2004 Jouni Malinen <j@w1.fi>

 *

 * 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 <crypto/internal/hash.h>

#include <asm/byteorder.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/string.h>

#include <linux/types.h>

​

​

struct michael_mic_ctx {

    u32 l, r;

};

​

struct michael_mic_desc_ctx {

    u8 pending[4];

    size_t pending_len;

​

    u32 l, r;

};

​

static inline u32 xswap(u32 val)

{

    return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);

}

​

​

#define michael_block(l, r) \

do {                \

    r ^= rol32(l, 17);  \

    l += r;         \

    r ^= xswap(l);      \

    l += r;         \

    r ^= rol32(l, 3);   \

    l += r;         \

    r ^= ror32(l, 2);   \

    l += r;         \

} while (0)

​

​

static int michael_init(struct shash_desc *desc)

{

    struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);

    struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);

    mctx->pending_len = 0;

    mctx->l = ctx->l;

    mctx->r = ctx->r;

​

    return 0;

}

​

​

static int michael_update(struct shash_desc *desc, const u8 *data,

               unsigned int len)

{

    struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);

    const __le32 *src;

​

    if (mctx->pending_len) {

        int flen = 4 - mctx->pending_len;

        if (flen > len)

            flen = len;

        memcpy(&mctx->pending[mctx->pending_len], data, flen);

        mctx->pending_len += flen;

        data += flen;

        len -= flen;

​

        if (mctx->pending_len < 4)

            return 0;

​

        src = (const __le32 *)mctx->pending;

        mctx->l ^= le32_to_cpup(src);

        michael_block(mctx->l, mctx->r);

        mctx->pending_len = 0;

    }

​

    src = (const __le32 *)data;

​

    while (len >= 4) {

        mctx->l ^= le32_to_cpup(src++);

        michael_block(mctx->l, mctx->r);

        len -= 4;

    }