/*
        mdfour.c

        An implementation of MD4 designed for use in the samba SMB
        authentication protocol

        Copyright (C) 1997-1998  Andrew Tridgell

        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:

                Free Software Foundation, Inc.
                59 Temple Place - Suite 330
                Boston, MA  02111-1307, USA

*/
#include <stdint.h>
#include <string.h> /* XoXus: needed for memset call */
#include "mdfour.h"

/* NOTE: This code makes no attempt to be fast!

   It assumes that a int32_t is at least 32 bits long
*/

static struct mdfour *m;

#define F(X, Y, Z) (((X) & (Y)) | ((~(X)) & (Z)))
#define G(X, Y, Z) (((X) & (Y)) | ((X) & (Z)) | ((Y) & (Z)))
#define H(X, Y, Z) ((X) ^ (Y) ^ (Z))
#ifdef LARGE_INT32
#define lshift(x, s) ((((x) << (s)) & 0xFFFFFFFF) | (((x) >> (32 - (s))) & 0xFFFFFFFF))
#else
#define lshift(x, s) (((x) << (s)) | ((x) >> (32 - (s))))
#endif

#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] + 0x5A827999, s)
#define ROUND3(a, b, c, d, k, s) a = lshift(a + H(b, c, d) + X[k] + 0x6ED9EBA1, s)

/* this applies md4 to 64 byte chunks */
static void mdfour64(uint32_t *M) {
    int32_t j;
    uint32_t AA, BB, CC, DD;
    uint32_t X[16];
    uint32_t A, B, C, D;

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

    A  = m->A;
    B  = m->B;
    C  = m->C;
    D  = m->D;
    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;

#ifdef LARGE_INT32
    A &= 0xFFFFFFFF;
    B &= 0xFFFFFFFF;
    C &= 0xFFFFFFFF;
    D &= 0xFFFFFFFF;
#endif

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

    m->A = A;
    m->B = B;
    m->C = C;
    m->D = D;
}

static void copy64(uint32_t *M, uint8_t *in) {
    int32_t 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(uint8_t *out, uint32_t x) {
    out[0] = x & 0xFF;
    out[1] = (x >> 8) & 0xFF;
    out[2] = (x >> 16) & 0xFF;
    out[3] = (x >> 24) & 0xFF;
}

void mdfour_begin(struct mdfour *md) {
    md->A      = 0x67452301;
    md->B      = 0xefcdab89;
    md->C      = 0x98badcfe;
    md->D      = 0x10325476;
    md->totalN = 0;
}

static void mdfour_tail(uint8_t *in, int32_t n) {
    uint8_t buf[128];
    uint32_t M[16];
    uint32_t b;

    m->totalN += n;

    b = m->totalN * 8;

    memset(buf, 0, 128);
    if (n)
        memcpy(buf, in, n);
    buf[n] = 0x80;

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

void mdfour_update(struct mdfour *md, uint8_t *in, int32_t n) {
    uint32_t M[16];

    if (n == 0)
        mdfour_tail(in, n);

    m = md;

    while (n >= 64) {
        copy64(M, in);
        mdfour64(M);
        in += 64;
        n -= 64;
        m->totalN += 64;
    }

    mdfour_tail(in, n);
}

void mdfour_result(struct mdfour *md, uint8_t *out) {
    m = md;

    copy4(out, m->A);
    copy4(out + 4, m->B);
    copy4(out + 8, m->C);
    copy4(out + 12, m->D);
}

void mdfour(uint8_t *out, uint8_t *in, int32_t n) {
    struct mdfour md;
    mdfour_begin(&md);
    mdfour_update(&md, in, n);
    mdfour_result(&md, out);
}

///////////////////////////////////////////////////////////////
//	MD4-based checksum utility functions
//
//	Copyright (C) 2000       Jeff Teunissen <d2deek@pmail.net>
//
//	Author: Jeff Teunissen	<d2deek@pmail.net>
//	Date: 01 Jan 2000

unsigned Com_BlockChecksum(void *buffer, int32_t length) {
    int32_t digest[4];
    unsigned val;

    mdfour((uint8_t *)digest, (uint8_t *)buffer, length);

    val = digest[0] ^ digest[1] ^ digest[2] ^ digest[3];

    return val;
}

void Com_BlockFullChecksum(void *buffer, int32_t len, uint8_t *outbuf) {
    mdfour(outbuf, (uint8_t *)buffer, len);
}