/*
 * Copyright (c) 1996, 2003 VIA Networking Technologies, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *
 * File: michael.cpp
 *
 * Purpose: The implementation of LIST data structure.
 *
 * Author: Kyle Hsu
 *
 * Date: Sep 4, 2002
 *
 * Functions:
 *      s_dwGetUINT32 - Convert from unsigned char [] to unsigned long in a portable way
 *      s_vPutUINT32 - Convert from unsigned long to unsigned char [] in a portable way
 *      s_vClear - Reset the state to the empty message.
 *      s_vSetKey - Set the key.
 *      MIC_vInit - Set the key.
 *      s_vAppendByte - Append the byte to our word-sized buffer.
 *      MIC_vAppend - call s_vAppendByte.
 *      MIC_vGetMIC - Append the minimum padding and call s_vAppendByte.
 *
 * Revision History:
 *
 */

#include "tmacro.h"
#include "michael.h"

/*---------------------  Static Definitions -------------------------*/

/*---------------------  Static Variables  --------------------------*/

/*---------------------  Static Functions  --------------------------*/
/*
  static unsigned long s_dwGetUINT32(unsigned char *p);         // Get unsigned long from 4 bytes LSByte first
  static void s_vPutUINT32(unsigned char *p, unsigned long val); // Put unsigned long into 4 bytes LSByte first
*/
static void s_vClear(void);                       // Clear the internal message,
// resets the object to the state just after construction.
static void s_vSetKey(unsigned long dwK0, unsigned long dwK1);
static void s_vAppendByte(unsigned char b);            // Add a single byte to the internal message

/*---------------------  Export Variables  --------------------------*/
static unsigned long L, R;           // Current state

static unsigned long K0, K1;         // Key
static unsigned long M;              // Message accumulator (single word)
static unsigned int nBytesInM;      // # bytes in M

/*---------------------  Export Functions  --------------------------*/

/*
  static unsigned long s_dwGetUINT32 (unsigned char *p)
// Convert from unsigned char [] to unsigned long in a portable way
{
unsigned long res = 0;
unsigned int i;
for (i=0; i<4; i++)
{
        res |= (*p++) << (8 * i);
}
return res;
}

static void s_vPutUINT32 (unsigned char *p, unsigned long val)
// Convert from unsigned long to unsigned char [] in a portable way
{
        unsigned int i;
        for (i=0; i<4; i++) {
                *p++ = (unsigned char) (val & 0xff);
                val >>= 8;
        }
}
*/

static void s_vClear(void)
{
        // Reset the state to the empty message.
        L = K0;
        R = K1;
        nBytesInM = 0;
        M = 0;
}

static void s_vSetKey(unsigned long dwK0, unsigned long dwK1)
{
        // Set the key
        K0 = dwK0;
        K1 = dwK1;
        // and reset the message
        s_vClear();
}

static void s_vAppendByte(unsigned char b)
{
        // Append the byte to our word-sized buffer
        M |= b << (8*nBytesInM);
        nBytesInM++;
        // Process the word if it is full.
        if (nBytesInM >= 4) {
                L ^= M;
                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;
                // Clear the buffer
                M = 0;
                nBytesInM = 0;
        }
}

void MIC_vInit(unsigned long dwK0, unsigned long dwK1)
{
        // Set the key
        s_vSetKey(dwK0, dwK1);
}

void MIC_vUnInit(void)
{
        // Wipe the key material
        K0 = 0;
        K1 = 0;

        // And the other fields as well.
        //Note that this sets (L,R) to (K0,K1) which is just fine.
        s_vClear();
}

void MIC_vAppend(unsigned char *src, unsigned int nBytes)
{
        // This is simple
        while (nBytes > 0) {
                s_vAppendByte(*src++);
                nBytes--;
        }
}

void MIC_vGetMIC(unsigned long *pdwL, unsigned long *pdwR)
{
        // Append the minimum padding
        s_vAppendByte(0x5a);
        s_vAppendByte(0);
        s_vAppendByte(0);
        s_vAppendByte(0);
        s_vAppendByte(0);
        // and then zeroes until the length is a multiple of 4
        while (nBytesInM != 0) {
                s_vAppendByte(0);
        }
        // The s_vAppendByte function has already computed the result.
        *pdwL = L;
        *pdwR = R;
        // Reset to the empty message.
        s_vClear();
}