/*
 * $Source$
 * $Author$
 *
 * Copyright 1985, 1986, 1987, 1988, 1990 by the Massachusetts Institute
 * of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 * 
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 * 
 *
 * These routines perform encryption and decryption using the DES
 * private key algorithm, or else a subset of it-- fewer inner loops.
 * (AUTH_DES_ITER defaults to 16, may be less.)
 *
 * Under U.S. law, this software may not be exported outside the US
 * without license from the U.S. Commerce department.
 *
 * The key schedule is passed as an arg, as well as the cleartext or
 * ciphertext.
 *
 * All registers labeled imply Vax using the Ultrix or 4.2bsd
 * compiler.
 *
 *
 *	NOTE:  bit and byte numbering:
 *			DES algorithm is defined in terms of bits of L
 *			followed by bits of R.
 *		bit 0  ==> lsb of L
 *		bit 63 ==> msb of R
 *
 * Always work in register pairs, FROM L1,R1 TO L2,R2 to make
 * bookkeeping easier.
 *
 * originally written by Steve Miller, MIT Project Athena
 */

#if !defined(lint) && !defined(SABER)
static char rcsid_des_c[] =
"$Id$";
#endif	/* !lint & !SABER */


#include <krb5/krb5.h>
#include <krb5/ext-proto.h>
#include "des_int.h"
#include "s_table.h"
#include "p_table.h"

#ifdef DEBUG
#define DBG_PRINT(s) if (mit_des_debug & 2) \
    mit_des_debug_print(s,i,L1&0xffff,(L1>>16)&0xffff, \
		R1&0xffff,(R1>>16)&0xffff)
#else
#define DBG_PRINT(s)
#endif

extern int mit_des_debug;

int
mit_des_ecb_encrypt(clear, cipher, schedule, encrypt)
    unsigned long *clear;
    unsigned long *cipher;
    int encrypt;		/* 0 ==> decrypt, else encrypt */
    register mit_des_key_schedule schedule; /* r11 */
{

    /* better pass 8 bytes, length not checked here */

    register unsigned long R1, L1; /* R1 = r10, L1 = r9 */
    register unsigned long R2, L2; /* R2 = r8, L2 = r7 */
    long i;
    /* one more registers left on VAX, see below P_temp_p */
#ifdef BITS16
    sbox_in_16_a S_in_16_a;
    sbox_in_16_b S_in_16_b;
    sbox_in_16_c S_in_16_c;
    unsigned int *S_in_a_16_p = (unsigned int *) &S_in_16_a;
    unsigned int *S_in_b_16_p = (unsigned int *) &S_in_16_b;
    unsigned int *S_in_c_16_p = (unsigned int *) &S_in_16_c;
#endif
#ifndef BITS32
#ifndef BITS16
    dunno how to do this machine type, you lose;
#endif
#endif
    unsigned long P_temp;
    register unsigned char *P_temp_p = (unsigned char *) & P_temp;
#ifdef BITS16
    sbox_out S_out;
    unsigned long *S_out_p = (unsigned long *) &S_out;
#endif
    unsigned long R_save, L_save;
#ifdef DEBUG
    unsigned long dbg_tmp[2];
#endif

    /*
     * Use L1,R1 and L2,R2 as two sets of "64-bit" registers always
     * work from L1,R1 input to L2,R2 output; initialize the cleartext
     * into registers.
     */
#ifdef MUSTALIGN
#ifdef DEBUG
    /*
     * If the alignment is wrong, the programmer really screwed up --
     * we aren't even getting the right data type.  His problem.  Keep
     * this code for debugging.
     */
    /* Make sure schedule is ok */
    if ((long) schedule & 3) {
	fprintf(stderr,"des.c schedule arg pointer not aligned\n");
	abort();
    }
#endif
    if ((long) clear & 3) {
	memcpy((char *)&L_save,(char *)clear++,sizeof(L_save));
	memcpy((char *)&R_save,(char *)clear,sizeof(R_save));
	L1 = L_save;
	R1 = R_save;
    }
    else
#endif
    {
	if (clear) L1 = *clear++;
	else L1 = 0;
	if (clear) R1 = *clear;
	else R1 = 0;
    }

#ifdef DEBUG
    if (mit_des_debug & 2) {
	printf("All values printed from low byte (bit 0)");
	printf(" --> high byte (bit 63)\n");
	i = 0;
	dbg_tmp[0] = L1;
	dbg_tmp[1] = R1;
	printf("iter = %2d  before IP\n\t\tL1 R1 = ",i);
	mit_des_cblock_print_file (dbg_tmp, stdout);
    }

    DBG_PRINT("before IP");
#endif

/*   IP_start:*/

    /* all the Initial Permutation code is in the include file */
#include "ip.c"
    /* reset input to L1,R1 */
    L1 = L2;
    R1 = R2;

    /* iterate through the inner loop */
    for (i = 0; i <= (AUTH_DES_ITER-1); i++) {

#ifdef DEBUG
	if (mit_des_debug & 2) {
	    dbg_tmp[0] = L1;
	    dbg_tmp[1] = R1;
	    printf("iter = %2d	start loop\n\t\tL1 R1 = ",i);
	    mit_des_cblock_print_file (dbg_tmp, stdout);
	    DBG_PRINT("start loop");
	}

#endif

	R_save = R1;
	L_save = L1;

/*   E_start:*/
	/* apply the E permutation from R1 to L2, R2 */
#ifndef VAXASM
#ifdef SLOW_E
#include "e.c"
#else /* Bill's fast E */
	L2 = (R1 << 1);
	if (R1 & (1<<31))
	    L2 |= 1<<0;
	L2 &= 077;
	L2 |= (R1 <<3) & 07700;
	L2 |= (R1 <<5) & 0770000;
	L2 |= (R1 <<7) & 077000000;
	L2 |= (R1 <<9) & 07700000000;
	L2 |= (R1 <<11) & 030000000000;

	/* now from right to right */

	R2 = ((R1 >> 17) & 0176000);
	if (R1 & (1<<0)) R2 |= 1<<15;

	R2 |= ((R1 >> 21) & 017);
	R2 |= ((R1 >> 19) & 01760);
#endif /* SLOW_E */
#else /* VAXASM */
	/* E operations */
	/* right to left */
	asm("	rotl	$1,r10,r7");
	L2 &= 077;
	L2 |= (R1 <<3) & 07700;
	L2 |= (R1 <<5) & 0770000;
	L2 |= (R1 <<7) & 077000000;
	L2 |= (R1 <<9) & 07700000000;
	L2 |= (R1 <<11) & 030000000000;

	asm("	rotl	$-17,r10,r8");
	R2 &= 0176000;
	asm("	rotl	$-21,r10,r0");
	asm("	bicl2	$-16,r0");
	asm("  bisl2	r0,r8");
	asm("	rotl	$-19,r10,r0");
	asm("	bicl2	$-1009,r0");
	asm("  bisl2	r0,r8");

#endif

	/* reset input to L1,R1 */
	L1 = L2;
	R1 = R2;

#ifdef DEBUG
	if (mit_des_debug & 2) {
	    dbg_tmp[0] = L1;
	    dbg_tmp[1] = R1;
	    DBG_PRINT("after e");
	    printf("iter = %2d	after e\n\t\tL1 R1 = ",i);
	    mit_des_cblock_print_file (dbg_tmp, stdout);
	}
#endif

/*   XOR_start:*/
	/*
	 * XOR with the key schedule, "schedule"
	 *
	 * If this is an encryption operation, use schedule[i],
	 * otherwise use schedule [AUTH_DES_ITER-i-1]
	 *
	 * First XOR left half.
	 */
	if (encrypt) {
	    L1 ^= *(((unsigned long *) &schedule[i] )+0);
	    /* now right half */
	    R1 ^= *(((unsigned long *) &schedule[i] )+1);
	}
	else {
	    L1 ^= *(((unsigned long *) &schedule[AUTH_DES_ITER-i-1] )+0);
	    /* now right half */
	    R1 ^= *(((unsigned long *) &schedule[AUTH_DES_ITER-i-1] )+1);
	}

	/* dont have to reset input to L1, R1 */

#ifdef DEBUG
	if (mit_des_debug & 2) {
	    dbg_tmp[0] = L1;
	    dbg_tmp[1] = R1;
	    DBG_PRINT("after xor");
	    printf("iter = %2d	after xor\n\t\tL1 R1 =",i);
	    mit_des_cblock_print_file (dbg_tmp, stdout);
	}
#endif

/*   S_start:*/
	/* apply the S selection from L1, R1 to R2 */

#ifdef notdef
#include "s.c"
#endif

	/* S operations , cant use registers for bit field stuff */
	/* from S_in to S_out */

#ifdef BITS16
	*S_in_a_16_p = L1&0xffff;
	*S_in_b_16_p = (L1>>16)&0xffff;
	*S_in_c_16_p = R1&0xffff;
	(*(unsigned long *) &S_out) =
	    (unsigned) S_adj[0][S_in_16_a.b0];
	S_out.b1 = (unsigned) S_adj[1][S_in_16_a.b1];
	/* b2 spans two words */
	S_out.b2 = (unsigned)
	    S_adj[2][(unsigned) S_in_16_a.b2
		     + (((unsigned) S_in_16_b.b2) << 4)];
	S_out.b3 = (unsigned) S_adj[3][S_in_16_b.b3];
	S_out.b4 = (unsigned) S_adj[4][S_in_16_b.b4];
	/* b5 spans both parts */
	S_out.b5 = (unsigned)
	    S_adj[5][(unsigned) S_in_16_b.b5
		     + (((unsigned) S_in_16_c.b5) << 2)];
	S_out.b6 = (unsigned) S_adj[6][S_in_16_c.b6];
	S_out.b7 = (unsigned) S_adj[7][S_in_16_c.b7];
	R1 = *S_out_p;
#else
	/* is a 32 bit sys */
#ifndef VAXASM
	R2 =  (unsigned) S_adj[0][L1 & 077];
	L2 = (unsigned) S_adj[1][(L1 >> 6) & 077];
	R2 |= (L2 <<4 );
	L2 = (unsigned) S_adj[2][(L1 >> 12) & 077];
	R2 |= (L2 <<8);
	L2 = (unsigned) S_adj[3][(L1 >> 18) & 077];
	R2 |= (L2 <<12);
	L2 = (unsigned) S_adj[4][(L1 >> 24) & 077];
	R2 |= (L2 <<16);
	/* b5 spans both parts */
	L2 = (unsigned)
	    S_adj[5][(unsigned) ((L1 >>30) & 03) + ((R1 & 017) << 2)];
	R2 |= (L2 << 20);
	L2 = (unsigned) S_adj[6][(R1 >> 4) & 077];
	R2 |= (L2 <<24);
	L2 = (unsigned) S_adj[7][(R1 >> 10) & 077];
	R1 = R2 | (L2 <<28);
	/* reset input to L1, R1 */
#else /* vaxasm */
	/*
	 * this is the c code produced above, with
	 * extzv replaced by rotl
	 */
	asm("bicl3	$-64,r9,r0");
	asm("movzbl	_S_adj[r0],r8");
	asm("rotl	$-6,r9,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+64[r0],r7");
	asm("ashl	$4,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-12,r9,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+128[r0],r7");
	asm("ashl	$8,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-18,r9,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+192[r0],r7");
	asm("ashl	$12,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-24,r9,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+256[r0],r7");
	asm("ashl	$16,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-30,r9,r0");
	asm("bicl2	$-4,r0");
	asm("bicl3	$-16,r10,r1");
	asm("ashl	$2,r1,r1");
	asm("addl2	r1,r0");
	asm("movzbl	_S_adj+320[r0],r7");
	asm("ashl	$20,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-4,r10,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+384[r0],r7");
	asm("ashl	$24,r7,r0");
	asm("bisl2	r0,r8");
	asm("rotl	$-10,r10,r0");
	asm("bicl2	$-64,r0");
	asm("movzbl	_S_adj+448[r0],r7");
	asm("ashl	$28,r7,r0");
	asm("bisl2	r8,r0");
	asm("movl	r0,r10");

#endif /* vaxasm */
#endif

#ifdef DEBUG
	if (mit_des_debug & 2) {
	    dbg_tmp[0] = L1;
	    dbg_tmp[1] = R1;
	    DBG_PRINT("after s");
	    printf("iter = %2d	after s\n\t\tL1 R1 = ",i);
	    mit_des_cblock_print_file (dbg_tmp, stdout);
	}
#endif

/*   P_start:*/
	/* and then the p permutation from R1 into R2 */
#include "p.c"
	/* reset the input to L1, R1 */
	R1 = R2;

#ifdef DEBUG
	if (mit_des_debug & 2) {
	    dbg_tmp[0] = L1;
	    dbg_tmp[1] = R1;
	    DBG_PRINT("after p");
	    printf("iter = %2d	after p\n\t\tL1 R1 = ",i);
	    mit_des_cblock_print_file (dbg_tmp, stdout);
	}
#endif

	/* R1 is the output value from the f() */
	/* move R[iter] to L[iter+1] */
/*   XOR_2_start:*/
	L1 = R_save;
	/* xor with left */
	R1 = L_save ^ R1;
	/* reset the input */
    }

    /* flip left and right before final permutation */
    L2 = R1;			/* flip */
    R2 = L1;
    /* reset the input */
    L1 = L2;
    R1 = R2;

#ifdef DEBUG
    if (mit_des_debug & 2) {
	dbg_tmp[0] = L1;
	dbg_tmp[1] = R1;
	DBG_PRINT("before FP");
	printf("iter = %2d  before FP\n\t\tL1 R1 = ",i);
	mit_des_cblock_print_file (dbg_tmp, stdout);
    }

#endif

/*FP_start:*/
    /* do the final permutation from L1R1 to L2R2 */
    /* all the fp code is in the include file */
#include "fp.c"

    /* copy the output to the ciphertext string;
     * can be same as cleartext
     */

#ifdef MUSTALIGN
    if ((long) cipher & 3) {
	L_save = L2;	/* cant bcopy a reg */
	R_save = R2;
	memcpy((char *)cipher++,(char *)&L_save,sizeof(L_save));
	memcpy((char *)cipher,(char *)&R_save,sizeof(R_save));
    }
    else
#endif
    {
	*cipher++ = L2;
	*cipher = R2;
    }

#ifdef DEBUG
    if (mit_des_debug & 2) {
	L1 = L2;
	R1 = R2;
	dbg_tmp[0] = L1;
	dbg_tmp[1] = R1;
	DBG_PRINT("done");
	printf("iter = %2d  done\n\t\tL1 R1 = ",i);
	mit_des_cblock_print_file (dbg_tmp, stdout);
    }
#endif

    /* that's it, no errors can be returned */
    return 0;
}