/*
 * encoding.c - encoding & decoding functions
 *
 * Copyright (C) 2003   Rodolfo Giometti <giometti@linux.com>
 *
 *   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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Original Copyright:
 *
 *   RFC 1321 compliant MD5 implementation, by Christophe Devine
 *   <devine@cr0.net>; this program is licensed under the GPL.
 */


#include <ctype.h>
#include <string.h>

#include "c6term.h"

#undef __u8	/* just in case... */
#undef __u32	/* just in case... */
#define __u8  unsigned char
#define __u32 unsigned long int

struct md5_context
{
    __u32 total[2];
    __u32 state[4];
    __u8 buffer[64];
};

/* --- Local function ------------------------------------------------------- */

#define GET_UINT32(n,b,i)                                     \
{                                                             \
    (n) = (__u32) ((__u8 *) b)[(i)]                           \
      | (((__u32) ((__u8 *) b)[(i)+1]) <<  8)                 \
      | (((__u32) ((__u8 *) b)[(i)+2]) << 16)                 \
      | (((__u32) ((__u8 *) b)[(i)+3]) << 24);                \
}

#define PUT_UINT32(n,b,i)                                     \
{                                                             \
    (((__u8 *) b)[(i)]  ) = (__u8) (((n)      ) & 0xFF);      \
    (((__u8 *) b)[(i)+1]) = (__u8) (((n) >>  8) & 0xFF);      \
    (((__u8 *) b)[(i)+2]) = (__u8) (((n) >> 16) & 0xFF);      \
    (((__u8 *) b)[(i)+3]) = (__u8) (((n) >> 24) & 0xFF);      \
}

void md5_starts( struct md5_context *ctx )
{
    ctx->total[0] = 0;
    ctx->total[1] = 0;
    ctx->state[0] = 0x67452301;
    ctx->state[1] = 0xEFCDAB89;
    ctx->state[2] = 0x98BADCFE;
    ctx->state[3] = 0x10325476;
}

void md5_process( struct md5_context *ctx, __u8 data[64] )
{
    __u32 A, B, C, D, X[16];

    GET_UINT32( X[0],  data,  0 );
    GET_UINT32( X[1],  data,  4 );
    GET_UINT32( X[2],  data,  8 );
    GET_UINT32( X[3],  data, 12 );
    GET_UINT32( X[4],  data, 16 );
    GET_UINT32( X[5],  data, 20 );
    GET_UINT32( X[6],  data, 24 );
    GET_UINT32( X[7],  data, 28 );
    GET_UINT32( X[8],  data, 32 );
    GET_UINT32( X[9],  data, 36 );
    GET_UINT32( X[10], data, 40 );
    GET_UINT32( X[11], data, 44 );
    GET_UINT32( X[12], data, 48 );
    GET_UINT32( X[13], data, 52 );
    GET_UINT32( X[14], data, 56 );
    GET_UINT32( X[15], data, 60 );

#define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define P(a,b,c,d,k,s,t)                                \
{                                                       \
    a += F(b,c,d) + X[k] + t; a = S(a,s) + b;           \
}

    A = ctx->state[0];
    B = ctx->state[1];
    C = ctx->state[2];
    D = ctx->state[3];

#define F(x,y,z) (z ^ (x & (y ^ z)))

    P( A, B, C, D,  0,  7, 0xD76AA478 );
    P( D, A, B, C,  1, 12, 0xE8C7B756 );
    P( C, D, A, B,  2, 17, 0x242070DB );
    P( B, C, D, A,  3, 22, 0xC1BDCEEE );
    P( A, B, C, D,  4,  7, 0xF57C0FAF );
    P( D, A, B, C,  5, 12, 0x4787C62A );
    P( C, D, A, B,  6, 17, 0xA8304613 );
    P( B, C, D, A,  7, 22, 0xFD469501 );
    P( A, B, C, D,  8,  7, 0x698098D8 );
    P( D, A, B, C,  9, 12, 0x8B44F7AF );
    P( C, D, A, B, 10, 17, 0xFFFF5BB1 );
    P( B, C, D, A, 11, 22, 0x895CD7BE );
    P( A, B, C, D, 12,  7, 0x6B901122 );
    P( D, A, B, C, 13, 12, 0xFD987193 );
    P( C, D, A, B, 14, 17, 0xA679438E );
    P( B, C, D, A, 15, 22, 0x49B40821 );

#undef F

#define F(x,y,z) (y ^ (z & (x ^ y)))

    P( A, B, C, D,  1,  5, 0xF61E2562 );
    P( D, A, B, C,  6,  9, 0xC040B340 );
    P( C, D, A, B, 11, 14, 0x265E5A51 );
    P( B, C, D, A,  0, 20, 0xE9B6C7AA );
    P( A, B, C, D,  5,  5, 0xD62F105D );
    P( D, A, B, C, 10,  9, 0x02441453 );
    P( C, D, A, B, 15, 14, 0xD8A1E681 );
    P( B, C, D, A,  4, 20, 0xE7D3FBC8 );
    P( A, B, C, D,  9,  5, 0x21E1CDE6 );
    P( D, A, B, C, 14,  9, 0xC33707D6 );
    P( C, D, A, B,  3, 14, 0xF4D50D87 );
    P( B, C, D, A,  8, 20, 0x455A14ED );
    P( A, B, C, D, 13,  5, 0xA9E3E905 );
    P( D, A, B, C,  2,  9, 0xFCEFA3F8 );
    P( C, D, A, B,  7, 14, 0x676F02D9 );
    P( B, C, D, A, 12, 20, 0x8D2A4C8A );

#undef F
    
#define F(x,y,z) (x ^ y ^ z)

    P( A, B, C, D,  5,  4, 0xFFFA3942 );
    P( D, A, B, C,  8, 11, 0x8771F681 );
    P( C, D, A, B, 11, 16, 0x6D9D6122 );
    P( B, C, D, A, 14, 23, 0xFDE5380C );
    P( A, B, C, D,  1,  4, 0xA4BEEA44 );
    P( D, A, B, C,  4, 11, 0x4BDECFA9 );
    P( C, D, A, B,  7, 16, 0xF6BB4B60 );
    P( B, C, D, A, 10, 23, 0xBEBFBC70 );
    P( A, B, C, D, 13,  4, 0x289B7EC6 );
    P( D, A, B, C,  0, 11, 0xEAA127FA );
    P( C, D, A, B,  3, 16, 0xD4EF3085 );
    P( B, C, D, A,  6, 23, 0x04881D05 );
    P( A, B, C, D,  9,  4, 0xD9D4D039 );
    P( D, A, B, C, 12, 11, 0xE6DB99E5 );
    P( C, D, A, B, 15, 16, 0x1FA27CF8 );
    P( B, C, D, A,  2, 23, 0xC4AC5665 );

#undef F

#define F(x,y,z) (y ^ (x | ~z))

    P( A, B, C, D,  0,  6, 0xF4292244 );
    P( D, A, B, C,  7, 10, 0x432AFF97 );
    P( C, D, A, B, 14, 15, 0xAB9423A7 );
    P( B, C, D, A,  5, 21, 0xFC93A039 );
    P( A, B, C, D, 12,  6, 0x655B59C3 );
    P( D, A, B, C,  3, 10, 0x8F0CCC92 );
    P( C, D, A, B, 10, 15, 0xFFEFF47D );
    P( B, C, D, A,  1, 21, 0x85845DD1 );
    P( A, B, C, D,  8,  6, 0x6FA87E4F );
    P( D, A, B, C, 15, 10, 0xFE2CE6E0 );
    P( C, D, A, B,  6, 15, 0xA3014314 );
    P( B, C, D, A, 13, 21, 0x4E0811A1 );
    P( A, B, C, D,  4,  6, 0xF7537E82 );
    P( D, A, B, C, 11, 10, 0xBD3AF235 );
    P( C, D, A, B,  2, 15, 0x2AD7D2BB );
    P( B, C, D, A,  9, 21, 0xEB86D391 );

#undef F

    ctx->state[0] += A;
    ctx->state[1] += B;
    ctx->state[2] += C;
    ctx->state[3] += D;
}

void md5_update( struct md5_context *ctx, __u8 *input, __u32 length )
{
    __u32 left, fill;

    if( ! length ) return;

    left = ( ctx->total[0] >> 3 ) & 0x3F;
    fill = 64 - left;

    ctx->total[0] += length <<  3;
    ctx->total[1] += length >> 29;

    ctx->total[0] &= 0xFFFFFFFF;
    ctx->total[1] += ctx->total[0] < length << 3;

    if( left && length >= fill )
    {
        memcpy( (void *) (ctx->buffer + left), (void *) input, fill );
        md5_process( ctx, ctx->buffer );
        length -= fill;
        input  += fill;
        left = 0;
    }

    while( length >= 64 )
    {
        md5_process( ctx, input );
        length -= 64;
        input  += 64;
    }

    if( length )
    {
        memcpy( (void *) (ctx->buffer + left), (void *) input, length );
    }
}

static __u8 md5_padding[64] =
{
 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

void md5_finish( struct md5_context *ctx, __u8 digest[16] )
{
    __u32 last, padn;
    __u8 msglen[8];

    PUT_UINT32( ctx->total[0], msglen, 0 );
    PUT_UINT32( ctx->total[1], msglen, 4 );

    last = ( ctx->total[0] >> 3 ) & 0x3F;
    padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );

    md5_update( ctx, md5_padding, padn );
    md5_update( ctx, msglen, 8 );

    PUT_UINT32( ctx->state[0], digest,  0 );
    PUT_UINT32( ctx->state[1], digest,  4 );
    PUT_UINT32( ctx->state[2], digest,  8 );
    PUT_UINT32( ctx->state[3], digest, 12 );
}

void GenerKey(unsigned char *pDest,unsigned char *pSorg){
    struct md5_context ctx;
    md5_starts( &ctx );
    md5_update( &ctx, (__u8 *) pSorg, strlen(pSorg));
    md5_finish( &ctx, pDest );
}

/* --- Public functions ----------------------------------------------------- */

void nickpass_encode(unsigned char *StrCode, unsigned char *StrDest, int Psw)
{
   unsigned char Strtemp[8]="ANOCI", tt[30];
   int i, temp;

   if (Psw) {
      int y = strlen(StrCode);
      memcpy(tt, StrCode, y);
      tt[y] = server_key[0];
      tt[y+1] = server_key[2];
      tt[y+2] =0;
   }
   else {
      memcpy(tt,Strtemp,5);
      tt[5] = tolower(StrCode[strlen((char *)StrCode)-1]);
      tt[6] = tolower(StrCode[0]);
      tt[7] = server_key[4];
      tt[8] = server_key[2];
      tt[9] = 0;
   }

   GenerKey(StrDest,tt);

   for (i = 0; i < 16; i++) {
      temp = StrDest[i];
      temp = temp%0x5E;
      temp += 0x20;
      StrDest[i] = temp;
   }
}

/* --- End of the MD5 implementation ---------------------------------------- */

/* 
 * The following functions are by Andrea Censi <mox.pearl@libero.it> and
 * BiGAlex <totalmeltdown@libero.it>
 */

void reorder_key_server(const unsigned char *unordered, unsigned char *ordered)
{
   int i;

   for (i = 0; i < 7; i++)
      ordered[i] = unordered[(unordered[5]*i)%7];
}

/* Encoding a network packet for remote server by using reordered
   server key (from reorder_key_server() function) */
/* This function is used also to decode an encoded messages from server */
void packet_encode(unsigned char *dst, unsigned char *src, int len)
{
   int i, j;

   for (j = i = 0; i < len; j = ++j%7, i++)
      dst[i] = src[i]^reordered_key[j];
}

