/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   a implementation of MD4 designed for use in the SMB authentication protocol
   Copyright (C) Andrew Tridgell 1997-1998.
   Modified by Steve French (sfrench@us.ibm.com) 2002-2003
   
   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.
*/

/* NOTE: This code makes no attempt to be fast! */
#include <stdio.h>
#include <string.h>
#include "r_types.h"

// TODO: rewrite with #define
static inline ut32 F(ut32 X, ut32 Y, ut32 Z) {
	return (X & Y) | ((~X) & Z);
}

static inline ut32 G(ut32 X, ut32 Y, ut32 Z) {
	return (X & Y) | (X & Z) | (Y & Z);
}

static inline ut32 H(ut32 X, ut32 Y, ut32 Z) {
	return X ^ Y ^ Z;
}

static inline ut32 lshift(ut32 x, int s) {
	x &= 0xFFFFFFFF;
	return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
}

#define ROUND1(a,b,c,d,k,s) (*a) = lshift((*a) + F(*b,*c,*d) + X[k], s)
#define ROUND2(a,b,c,d,k,s) (*a) = lshift((*a) + G(*b,*c,*d) + X[k] + (ut32)0x5A827999,s)
#define ROUND3(a,b,c,d,k,s) (*a) = lshift((*a) + H(*b,*c,*d) + X[k] + (ut32)0x6ED9EBA1,s)

/* this applies md4 to 64 byte chunks */
static void mdfour64(ut32 * M, ut32 * A, ut32 *B, ut32 * C, ut32 *D) {
	int j;
	ut32 AA, BB, CC, DD;
	ut32 X[16];

	for (j = 0; j < 16; j++)
		X[j] = M[j];

	AA = *A;
	BB = *B;
	CC = *C;
	DD = *D;

	ROUND1 (A, B, C, D, 0, 3);
	ROUND1 (D, A, B, C, 1, 7);
	ROUND1 (C, D, A, B, 2, 11);
	ROUND1 (B, C, D, A, 3, 19);
	ROUND1 (A, B, C, D, 4, 3);
	ROUND1 (D, A, B, C, 5, 7);
	ROUND1 (C, D, A, B, 6, 11);
	ROUND1 (B, C, D, A, 7, 19);
	ROUND1 (A, B, C, D, 8, 3);
	ROUND1 (D, A, B, C, 9, 7);
	ROUND1 (C, D, A, B, 10, 11);
	ROUND1 (B, C, D, A, 11, 19);
	ROUND1 (A, B, C, D, 12, 3);
	ROUND1 (D, A, B, C, 13, 7);
	ROUND1 (C, D, A, B, 14, 11);
	ROUND1 (B, C, D, A, 15, 19);

	ROUND2 (A, B, C, D, 0, 3);
	ROUND2 (D, A, B, C, 4, 5);
	ROUND2 (C, D, A, B, 8, 9);
	ROUND2 (B, C, D, A, 12, 13);
	ROUND2 (A, B, C, D, 1, 3);
	ROUND2 (D, A, B, C, 5, 5);
	ROUND2 (C, D, A, B, 9, 9);
	ROUND2 (B, C, D, A, 13, 13);
	ROUND2 (A, B, C, D, 2, 3);
	ROUND2 (D, A, B, C, 6, 5);
	ROUND2 (C, D, A, B, 10, 9);
	ROUND2 (B, C, D, A, 14, 13);
	ROUND2 (A, B, C, D, 3, 3);
	ROUND2 (D, A, B, C, 7, 5);
	ROUND2 (C, D, A, B, 11, 9);
	ROUND2 (B, C, D, A, 15, 13);

	ROUND3 (A, B, C, D, 0, 3);
	ROUND3 (D, A, B, C, 8, 9);
	ROUND3 (C, D, A, B, 4, 11);
	ROUND3 (B, C, D, A, 12, 15);
	ROUND3 (A, B, C, D, 2, 3);
	ROUND3 (D, A, B, C, 10, 9);
	ROUND3 (C, D, A, B, 6, 11);
	ROUND3 (B, C, D, A, 14, 15);
	ROUND3 (A, B, C, D, 1, 3);
	ROUND3 (D, A, B, C, 9, 9);
	ROUND3 (C, D, A, B, 5, 11);
	ROUND3 (B, C, D, A, 13, 15);
	ROUND3 (A, B, C, D, 3, 3);
	ROUND3 (D, A, B, C, 11, 9);
	ROUND3 (C, D, A, B, 7, 11);
	ROUND3 (B, C, D, A, 15, 15);

	*A += AA;
	*B += BB;
	*C += CC;
	*D += DD;

	*A &= 0xFFFFFFFF;
	*B &= 0xFFFFFFFF;
	*C &= 0xFFFFFFFF;
	*D &= 0xFFFFFFFF;

	for (j = 0; j < 16; j++)
		X[j] = 0;
}

static void copy64(ut32 * M, const ut8 *in) {
	int i;
	for (i = 0; i < 16; i++)
		M[i] = (in[i * 4 + 3] << 24) | (in[i * 4 + 2] << 16) |
		    (in[i * 4 + 1] << 8) | (in[i * 4 + 0] << 0);
}

static void copy4(ut8 *out, ut32 x) {
	out[0] = x & 0xFF;
	out[1] = (x >> 8) & 0xFF;
	out[2] = (x >> 16) & 0xFF;
	out[3] = (x >> 24) & 0xFF;
}

/* produce a md4 message digest from data of length n bytes */
// XXX : rename as a static method
R_API void mdfour(ut8 *out, const ut8 *in, int n) {
	unsigned char buf[128];
	ut32 M[16];
	ut32 b = n * 8;
	int i;
	ut32 A = 0x67452301;
	ut32 B = 0xefcdab89;
	ut32 C = 0x98badcfe;
	ut32 D = 0x10325476;

	while (n > 64) {
		copy64 (M, in);
		mdfour64 (M,&A,&B, &C, &D);
		in += 64;
		n -= 64;
	}

	for (i = 0; i < 128; i++)
		buf[i] = 0;
	memcpy (buf, in, n);
	buf[n] = 0x80;

	if (n <= 55) {
		copy4 (buf + 56, b);
		copy64 (M, buf);
		mdfour64 (M, &A, &B, &C, &D);
	} else {
		copy4 (buf + 120, b);
		copy64 (M, buf);
		mdfour64 (M, &A, &B, &C, &D);
		copy64 (M, buf + 64);
		mdfour64 (M, &A, &B, &C, &D);
	}

	for (i = 0; i < 128; i++)
		buf[i] = 0;
	copy64 (M, buf);

	copy4 (out, A);
	copy4 (out + 4, B);
	copy4 (out + 8, C);
	copy4 (out + 12, D);

	A = B = C = D = 0;
}