/*
 *  FIPS-46-3 compliant Triple-DES implementation
 *
 *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
 *
 *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *  
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *  DES, on which TDES is based, was originally designed by Horst Feistel
 *  at IBM in 1974, and was adopted as a standard by NIST (formerly NBS).
 *
 *  http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf
 */

#include "lwip/opt.h"
#if PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_DES

#include "netif/ppp/polarssl/des.h"

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_ULONG_BE
#define GET_ULONG_BE(n,b,i)                             \
{                                                       \
    (n) = ( (unsigned long) (b)[(i)    ] << 24 )        \
        | ( (unsigned long) (b)[(i) + 1] << 16 )        \
        | ( (unsigned long) (b)[(i) + 2] <<  8 )        \
        | ( (unsigned long) (b)[(i) + 3]       );       \
}
#endif

#ifndef PUT_ULONG_BE
#define PUT_ULONG_BE(n,b,i)                             \
{                                                       \
    (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
    (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
    (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
    (b)[(i) + 3] = (unsigned char) ( (n)       );       \
}
#endif

/*
 * Expanded DES S-boxes
 */
static const unsigned long SB1[64] =
{
    0x01010400, 0x00000000, 0x00010000, 0x01010404,
    0x01010004, 0x00010404, 0x00000004, 0x00010000,
    0x00000400, 0x01010400, 0x01010404, 0x00000400,
    0x01000404, 0x01010004, 0x01000000, 0x00000004,
    0x00000404, 0x01000400, 0x01000400, 0x00010400,
    0x00010400, 0x01010000, 0x01010000, 0x01000404,
    0x00010004, 0x01000004, 0x01000004, 0x00010004,
    0x00000000, 0x00000404, 0x00010404, 0x01000000,
    0x00010000, 0x01010404, 0x00000004, 0x01010000,
    0x01010400, 0x01000000, 0x01000000, 0x00000400,
    0x01010004, 0x00010000, 0x00010400, 0x01000004,
    0x00000400, 0x00000004, 0x01000404, 0x00010404,
    0x01010404, 0x00010004, 0x01010000, 0x01000404,
    0x01000004, 0x00000404, 0x00010404, 0x01010400,
    0x00000404, 0x01000400, 0x01000400, 0x00000000,
    0x00010004, 0x00010400, 0x00000000, 0x01010004
};

static const unsigned long SB2[64] =
{
    0x80108020, 0x80008000, 0x00008000, 0x00108020,
    0x00100000, 0x00000020, 0x80100020, 0x80008020,
    0x80000020, 0x80108020, 0x80108000, 0x80000000,
    0x80008000, 0x00100000, 0x00000020, 0x80100020,
    0x00108000, 0x00100020, 0x80008020, 0x00000000,
    0x80000000, 0x00008000, 0x00108020, 0x80100000,
    0x00100020, 0x80000020, 0x00000000, 0x00108000,
    0x00008020, 0x80108000, 0x80100000, 0x00008020,
    0x00000000, 0x00108020, 0x80100020, 0x00100000,
    0x80008020, 0x80100000, 0x80108000, 0x00008000,
    0x80100000, 0x80008000, 0x00000020, 0x80108020,
    0x00108020, 0x00000020, 0x00008000, 0x80000000,
    0x00008020, 0x80108000, 0x00100000, 0x80000020,
    0x00100020, 0x80008020, 0x80000020, 0x00100020,
    0x00108000, 0x00000000, 0x80008000, 0x00008020,
    0x80000000, 0x80100020, 0x80108020, 0x00108000
};

static const unsigned long SB3[64] =
{
    0x00000208, 0x08020200, 0x00000000, 0x08020008,
    0x08000200, 0x00000000, 0x00020208, 0x08000200,
    0x00020008, 0x08000008, 0x08000008, 0x00020000,
    0x08020208, 0x00020008, 0x08020000, 0x00000208,
    0x08000000, 0x00000008, 0x08020200, 0x00000200,
    0x00020200, 0x08020000, 0x08020008, 0x00020208,
    0x08000208, 0x00020200, 0x00020000, 0x08000208,
    0x00000008, 0x08020208, 0x00000200, 0x08000000,
    0x08020200, 0x08000000, 0x00020008, 0x00000208,
    0x00020000, 0x08020200, 0x08000200, 0x00000000,
    0x00000200, 0x00020008, 0x08020208, 0x08000200,
    0x08000008, 0x00000200, 0x00000000, 0x08020008,
    0x08000208, 0x00020000, 0x08000000, 0x08020208,
    0x00000008, 0x00020208, 0x00020200, 0x08000008,
    0x08020000, 0x08000208, 0x00000208, 0x08020000,
    0x00020208, 0x00000008, 0x08020008, 0x00020200
};

static const unsigned long SB4[64] =
{
    0x00802001, 0x00002081, 0x00002081, 0x00000080,
    0x00802080, 0x00800081, 0x00800001, 0x00002001,
    0x00000000, 0x00802000, 0x00802000, 0x00802081,
    0x00000081, 0x00000000, 0x00800080, 0x00800001,
    0x00000001, 0x00002000, 0x00800000, 0x00802001,
    0x00000080, 0x00800000, 0x00002001, 0x00002080,
    0x00800081, 0x00000001, 0x00002080, 0x00800080,
    0x00002000, 0x00802080, 0x00802081, 0x00000081,
    0x00800080, 0x00800001, 0x00802000, 0x00802081,
    0x00000081, 0x00000000, 0x00000000, 0x00802000,
    0x00002080, 0x00800080, 0x00800081, 0x00000001,
    0x00802001, 0x00002081, 0x00002081, 0x00000080,
    0x00802081, 0x00000081, 0x00000001, 0x00002000,
    0x00800001, 0x00002001, 0x00802080, 0x00800081,
    0x00002001, 0x00002080, 0x00800000, 0x00802001,
    0x00000080, 0x00800000, 0x00002000, 0x00802080
};

static const unsigned long SB5[64] =
{
    0x00000100, 0x02080100, 0x02080000, 0x42000100,
    0x00080000, 0x00000100, 0x40000000, 0x02080000,
    0x40080100, 0x00080000, 0x02000100, 0x40080100,
    0x42000100, 0x42080000, 0x00080100, 0x40000000,
    0x02000000, 0x40080000, 0x40080000, 0x00000000,
    0x40000100, 0x42080100, 0x42080100, 0x02000100,
    0x42080000, 0x40000100, 0x00000000, 0x42000000,
    0x02080100, 0x02000000, 0x42000000, 0x00080100,
    0x00080000, 0x42000100, 0x00000100, 0x02000000,
    0x40000000, 0x02080000, 0x42000100, 0x40080100,
    0x02000100, 0x40000000, 0x42080000, 0x02080100,
    0x40080100, 0x00000100, 0x02000000, 0x42080000,
    0x42080100, 0x00080100, 0x42000000, 0x42080100,
    0x02080000, 0x00000000, 0x40080000, 0x42000000,
    0x00080100, 0x02000100, 0x40000100, 0x00080000,
    0x00000000, 0x40080000, 0x02080100, 0x40000100
};

static const unsigned long SB6[64] =
{
    0x20000010, 0x20400000, 0x00004000, 0x20404010,
    0x20400000, 0x00000010, 0x20404010, 0x00400000,
    0x20004000, 0x00404010, 0x00400000, 0x20000010,
    0x00400010, 0x20004000, 0x20000000, 0x00004010,
    0x00000000, 0x00400010, 0x20004010, 0x00004000,
    0x00404000, 0x20004010, 0x00000010, 0x20400010,
    0x20400010, 0x00000000, 0x00404010, 0x20404000,
    0x00004010, 0x00404000, 0x20404000, 0x20000000,
    0x20004000, 0x00000010, 0x20400010, 0x00404000,
    0x20404010, 0x00400000, 0x00004010, 0x20000010,
    0x00400000, 0x20004000, 0x20000000, 0x00004010,
    0x20000010, 0x20404010, 0x00404000, 0x20400000,
    0x00404010, 0x20404000, 0x00000000, 0x20400010,
    0x00000010, 0x00004000, 0x20400000, 0x00404010,
    0x00004000, 0x00400010, 0x20004010, 0x00000000,
    0x20404000, 0x20000000, 0x00400010, 0x20004010
};

static const unsigned long SB7[64] =
{
    0x00200000, 0x04200002, 0x04000802, 0x00000000,
    0x00000800, 0x04000802, 0x00200802, 0x04200800,
    0x04200802, 0x00200000, 0x00000000, 0x04000002,
    0x00000002, 0x04000000, 0x04200002, 0x00000802,
    0x04000800, 0x00200802, 0x00200002, 0x04000800,
    0x04000002, 0x04200000, 0x04200800, 0x00200002,
    0x04200000, 0x00000800, 0x00000802, 0x04200802,
    0x00200800, 0x00000002, 0x04000000, 0x00200800,
    0x04000000, 0x00200800, 0x00200000, 0x04000802,
    0x04000802, 0x04200002, 0x04200002, 0x00000002,
    0x00200002, 0x04000000, 0x04000800, 0x00200000,
    0x04200800, 0x00000802, 0x00200802, 0x04200800,
    0x00000802, 0x04000002, 0x04200802, 0x04200000,
    0x00200800, 0x00000000, 0x00000002, 0x04200802,
    0x00000000, 0x00200802, 0x04200000, 0x00000800,
    0x04000002, 0x04000800, 0x00000800, 0x00200002
};

static const unsigned long SB8[64] =
{
    0x10001040, 0x00001000, 0x00040000, 0x10041040,
    0x10000000, 0x10001040, 0x00000040, 0x10000000,
    0x00040040, 0x10040000, 0x10041040, 0x00041000,
    0x10041000, 0x00041040, 0x00001000, 0x00000040,
    0x10040000, 0x10000040, 0x10001000, 0x00001040,
    0x00041000, 0x00040040, 0x10040040, 0x10041000,
    0x00001040, 0x00000000, 0x00000000, 0x10040040,
    0x10000040, 0x10001000, 0x00041040, 0x00040000,
    0x00041040, 0x00040000, 0x10041000, 0x00001000,
    0x00000040, 0x10040040, 0x00001000, 0x00041040,
    0x10001000, 0x00000040, 0x10000040, 0x10040000,
    0x10040040, 0x10000000, 0x00040000, 0x10001040,
    0x00000000, 0x10041040, 0x00040040, 0x10000040,
    0x10040000, 0x10001000, 0x10001040, 0x00000000,
    0x10041040, 0x00041000, 0x00041000, 0x00001040,
    0x00001040, 0x00040040, 0x10000000, 0x10041000
};

/*
 * PC1: left and right halves bit-swap
 */
static const unsigned long LHs[16] =
{
    0x00000000, 0x00000001, 0x00000100, 0x00000101,
    0x00010000, 0x00010001, 0x00010100, 0x00010101,
    0x01000000, 0x01000001, 0x01000100, 0x01000101,
    0x01010000, 0x01010001, 0x01010100, 0x01010101
};

static const unsigned long RHs[16] =
{
    0x00000000, 0x01000000, 0x00010000, 0x01010000,
    0x00000100, 0x01000100, 0x00010100, 0x01010100,
    0x00000001, 0x01000001, 0x00010001, 0x01010001,
    0x00000101, 0x01000101, 0x00010101, 0x01010101,
};

/*
 * Initial Permutation macro
 */
#define DES_IP(X,Y)                                             \
{                                                               \
    T = ((X >>  4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T <<  4);   \
    T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16);   \
    T = ((Y >>  2) ^ X) & 0x33333333; X ^= T; Y ^= (T <<  2);   \
    T = ((Y >>  8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T <<  8);   \
    Y = ((Y << 1) | (Y >> 31)) & 0xFFFFFFFF;                    \
    T = (X ^ Y) & 0xAAAAAAAA; Y ^= T; X ^= T;                   \
    X = ((X << 1) | (X >> 31)) & 0xFFFFFFFF;                    \
}

/*
 * Final Permutation macro
 */
#define DES_FP(X,Y)                                             \
{                                                               \
    X = ((X << 31) | (X >> 1)) & 0xFFFFFFFF;                    \
    T = (X ^ Y) & 0xAAAAAAAA; X ^= T; Y ^= T;                   \
    Y = ((Y << 31) | (Y >> 1)) & 0xFFFFFFFF;                    \
    T = ((Y >>  8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T <<  8);   \
    T = ((Y >>  2) ^ X) & 0x33333333; X ^= T; Y ^= (T <<  2);   \
    T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16);   \
    T = ((X >>  4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T <<  4);   \
}

/*
 * DES round macro
 */
#define DES_ROUND(X,Y)                          \
{                                               \
    T = *SK++ ^ X;                              \
    Y ^= SB8[ (T      ) & 0x3F ] ^              \
         SB6[ (T >>  8) & 0x3F ] ^              \
         SB4[ (T >> 16) & 0x3F ] ^              \
         SB2[ (T >> 24) & 0x3F ];               \
                                                \
    T = *SK++ ^ ((X << 28) | (X >> 4));         \
    Y ^= SB7[ (T      ) & 0x3F ] ^              \
         SB5[ (T >>  8) & 0x3F ] ^              \
         SB3[ (T >> 16) & 0x3F ] ^              \
         SB1[ (T >> 24) & 0x3F ];               \
}

#define SWAP(a,b) { unsigned long t = a; a = b; b = t; t = 0; }

static void des_setkey( unsigned long SK[32], unsigned char key[8] )
{
    int i;
    unsigned long X, Y, T;

    GET_ULONG_BE( X, key, 0 );
    GET_ULONG_BE( Y, key, 4 );

    /*
     * Permuted Choice 1
     */
    T =  ((Y >>  4) ^ X) & 0x0F0F0F0F;  X ^= T; Y ^= (T <<  4);
    T =  ((Y      ) ^ X) & 0x10101010;  X ^= T; Y ^= (T      );

    X =   (LHs[ (X      ) & 0xF] << 3) | (LHs[ (X >>  8) & 0xF ] << 2)
        | (LHs[ (X >> 16) & 0xF] << 1) | (LHs[ (X >> 24) & 0xF ]     )
        | (LHs[ (X >>  5) & 0xF] << 7) | (LHs[ (X >> 13) & 0xF ] << 6)
        | (LHs[ (X >> 21) & 0xF] << 5) | (LHs[ (X >> 29) & 0xF ] << 4);

    Y =   (RHs[ (Y >>  1) & 0xF] << 3) | (RHs[ (Y >>  9) & 0xF ] << 2)
        | (RHs[ (Y >> 17) & 0xF] << 1) | (RHs[ (Y >> 25) & 0xF ]     )
        | (RHs[ (Y >>  4) & 0xF] << 7) | (RHs[ (Y >> 12) & 0xF ] << 6)
        | (RHs[ (Y >> 20) & 0xF] << 5) | (RHs[ (Y >> 28) & 0xF ] << 4);

    X &= 0x0FFFFFFF;
    Y &= 0x0FFFFFFF;

    /*
     * calculate subkeys
     */
    for( i = 0; i < 16; i++ )
    {
        if( i < 2 || i == 8 || i == 15 )
        {
            X = ((X <<  1) | (X >> 27)) & 0x0FFFFFFF;
            Y = ((Y <<  1) | (Y >> 27)) & 0x0FFFFFFF;
        }
        else
        {
            X = ((X <<  2) | (X >> 26)) & 0x0FFFFFFF;
            Y = ((Y <<  2) | (Y >> 26)) & 0x0FFFFFFF;
        }

        *SK++ =   ((X <<  4) & 0x24000000) | ((X << 28) & 0x10000000)
                | ((X << 14) & 0x08000000) | ((X << 18) & 0x02080000)
                | ((X <<  6) & 0x01000000) | ((X <<  9) & 0x00200000)
                | ((X >>  1) & 0x00100000) | ((X << 10) & 0x00040000)
                | ((X <<  2) & 0x00020000) | ((X >> 10) & 0x00010000)
                | ((Y >> 13) & 0x00002000) | ((Y >>  4) & 0x00001000)
                | ((Y <<  6) & 0x00000800) | ((Y >>  1) & 0x00000400)
                | ((Y >> 14) & 0x00000200) | ((Y      ) & 0x00000100)
                | ((Y >>  5) & 0x00000020) | ((Y >> 10) & 0x00000010)
                | ((Y >>  3) & 0x00000008) | ((Y >> 18) & 0x00000004)
                | ((Y >> 26) & 0x00000002) | ((Y >> 24) & 0x00000001);

        *SK++ =   ((X << 15) & 0x20000000) | ((X << 17) & 0x10000000)
                | ((X << 10) & 0x08000000) | ((X << 22) & 0x04000000)
                | ((X >>  2) & 0x02000000) | ((X <<  1) & 0x01000000)
                | ((X << 16) & 0x00200000) | ((X << 11) & 0x00100000)
                | ((X <<  3) & 0x00080000) | ((X >>  6) & 0x00040000)
                | ((X << 15) & 0x00020000) | ((X >>  4) & 0x00010000)
                | ((Y >>  2) & 0x00002000) | ((Y <<  8) & 0x00001000)
                | ((Y >> 14) & 0x00000808) | ((Y >>  9) & 0x00000400)
                | ((Y      ) & 0x00000200) | ((Y <<  7) & 0x00000100)
                | ((Y >>  7) & 0x00000020) | ((Y >>  3) & 0x00000011)
                | ((Y <<  2) & 0x00000004) | ((Y >> 21) & 0x00000002);
    }
}

/*
 * DES key schedule (56-bit, encryption)
 */
void des_setkey_enc( des_context *ctx, unsigned char key[8] )
{
    des_setkey( ctx->sk, key );
}

/*
 * DES key schedule (56-bit, decryption)
 */
void des_setkey_dec( des_context *ctx, unsigned char key[8] )
{
    int i;

    des_setkey( ctx->sk, key );

    for( i = 0; i < 16; i += 2 )
    {
        SWAP( ctx->sk[i    ], ctx->sk[30 - i] );
        SWAP( ctx->sk[i + 1], ctx->sk[31 - i] );
    }
}

/*
 * DES-ECB block encryption/decryption
 */
void des_crypt_ecb( des_context *ctx,
                    const unsigned char input[8],
                    unsigned char output[8] )
{
    int i;
    unsigned long X, Y, T, *SK;

    SK = ctx->sk;

    GET_ULONG_BE( X, input, 0 );
    GET_ULONG_BE( Y, input, 4 );

    DES_IP( X, Y );

    for( i = 0; i < 8; i++ )
    {
        DES_ROUND( Y, X );
        DES_ROUND( X, Y );
    }

    DES_FP( Y, X );

    PUT_ULONG_BE( Y, output, 0 );
    PUT_ULONG_BE( X, output, 4 );
}

#endif /* PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_DES */

