md5c.c

uCLinux下的一个TCP/IP协议栈源码

  HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

  /* Round 4 */
  II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
  II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
  II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
  II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
  II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
  II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
  II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
  II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
  II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
  II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  
  /* Zeroize sensitive information.
   */
  memset ((POINTER)x, 0, sizeof (x));
}

#endif

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
     a multiple of 4.
 */
static void Encode (output, input, len)
unsigned char *output;
UINT4 *input;
unsigned int len;
{
  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4) {
    output[j] = (unsigned char)(input[i] & 0xff);
    output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
    output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
    output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
  }
}

#ifndef	CPU386	/* Not needed in assembler version */
/* Decodes input (unsigned char) into output (UINT4). Assumes len is
     a multiple of 4.
 */
static void Decode (output, input, len)
UINT4 *output;
unsigned char *input;
unsigned int len;
{
  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4)
    output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
      (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
}
#else	/* CPU386 */
/* Fast 386 Borland C inline assembler version of the transform() function
 * from the RSA Data Security, Inc, MD5 Message Digest Algorithm.
 *
 * This version uses native 32 bit registers, so it needs a 386 or 486 CPU.
 * It also assumes large model (-ml)
 *
 * Because this function does *lots* of 32-bit operations, this version is
 * MUCH faster than the reference C version compiled with a garden-
 * variety 16-bit MS-DOS C compiler.
 *
 * Originally written and placed into the public domain on
 * 22 February 1992 by Phil Karn, KA9Q
 *
 * Updated 1 Sept 1994 by Phil Karn to match newer version of MD5.C released
 * in the RSAREF package. Also changed some register assignments to get rid
 * of the segment override prefixes on memory references
 */


/* Code sequence common to all four rounds.
 * evaluates a = b + (a + edi + x + t) <<< s
 * where it is assumed a and b are registers, x is a memory location,
 * edi is the edi register, and s and t are integer constants
 */
#define	COM(a,b,x,s,t)\
	lea a,t[a+edi];\
	add a,x;\
	rol a,s;\
	add a,b;

/* Round 1 functions */
/* edi = F(x,y,z) = (x & y) | (~x & z) */
#define	F(x,y,z)\
	mov edi,x;\
	and edi,y;\
	mov ebp,x;\
	not ebp;\
	and ebp,z;\
	or edi,ebp

/* a = b + ((a + F(b,c,d) + x + t) <<< s); */
#define	FF(a,b,c,d,x,s,t)\
	F(b,c,d);\
	COM(a,b,x,s,t)

/* Round 2 functions */
/* edi = G(x,y,z) = F(z,x,y) = (x & z) | (y & ~z) */
#define	G(x,y,z) F(z,x,y)

/* a = b + ((a + G(b,c,d) + x + t) <<< s) */
#define	GG(a,b,c,d,x,s,t)\
	G(b,c,d);\
	COM(a,b,x,s,t)

/* Round 3 functions */
/* edi = H(x,y,z) = x ^ y ^ z */
#define	H(x,y,z)\
	mov edi,x;\
	xor edi,y;\
	xor edi,z

/* a = b + ((a + H(b,c,d) + x + t) <<< s) */
#define	HH(a,b,c,d,x,s,t)\
	H(b,c,d);\
	COM(a,b,x,s,t)

/* Round 4 functions */
/* edi = I(x,y,z) = y ^ (x | ~z) */
#define	I(x,y,z)\
	mov edi,z;\
	not edi;\
	or edi,x;\
	xor edi,y

/* a = b + ((a + I(b,c,d) + x + t) <<< s) */
#define	II(a,b,c,d,x,s,t)\
	I(b,c,d);\
	COM(a,b,x,s,t)

/* Register assignments */
#define	A	eax
#define	B	ebx
#define	C	ecx
#define	D	edx

static void
MD5Transform (state, block)
UINT4 state[4];
unsigned char block[64];
{
	asm {

	/* Save caller's registers */
	push si;
	push edi;
	push ds;

	lds si,state;	/* Read input state */

	mov A,dword ptr si[0*4];	/* A = state[0] */
	mov B,dword ptr si[1*4];	/* B = state[1] */
	mov C,dword ptr si[2*4];	/* C = state[2] */
	mov D,dword ptr si[3*4];	/* D = state[3] */

	lds si,block;	/* Set up for data block read */

	/* The FF macro uses ebp as scratch. This makes our args
	 * inaccessible until it is restored!
	 */
	push ebp;

	/* Round 1. The *4 factors in the subscripts to si account for the
	 * byte offsets of each long element in the input array. The input
	 * is actually a byte array, but we can treat it directly as a long
	 * array because MD5 is little-endian, like the 386/486.
	 *
	 * The only hazard is if the input buffer isn't 32-bit aligned,
	 * things will run a little more slowly.
	 */
	FF(A,B,C,D,si[ 0*4],S11,3614090360); /* 1 */
	FF(D,A,B,C,si[ 1*4],S12,3905402710); /* 2 */
	FF(C,D,A,B,si[ 2*4],S13, 606105819); /* 3 */
	FF(B,C,D,A,si[ 3*4],S14,3250441966); /* 4 */
	FF(A,B,C,D,si[ 4*4],S11,4118548399); /* 5 */
	FF(D,A,B,C,si[ 5*4],S12,1200080426); /* 6 */
	FF(C,D,A,B,si[ 6*4],S13,2821735955); /* 7 */
	FF(B,C,D,A,si[ 7*4],S14,4249261313); /* 8 */
	FF(A,B,C,D,si[ 8*4],S11,1770035416); /* 9 */
	FF(D,A,B,C,si[ 9*4],S12,2336552879); /* 10 */
	FF(C,D,A,B,si[10*4],S13,4294925233); /* 11 */
	FF(B,C,D,A,si[11*4],S14,2304563134); /* 12 */
	FF(A,B,C,D,si[12*4],S11,1804603682); /* 13 */
	FF(D,A,B,C,si[13*4],S12,4254626195); /* 14 */
	FF(C,D,A,B,si[14*4],S13,2792965006); /* 15 */
	FF(B,C,D,A,si[15*4],S14,1236535329); /* 16 */

	/* Round 2 */
	GG(A,B,C,D,si[ 1*4],S21,4129170786); /* 17 */
	GG(D,A,B,C,si[ 6*4],S22,3225465664); /* 18 */
	GG(C,D,A,B,si[11*4],S23, 643717713); /* 19 */
	GG(B,C,D,A,si[ 0*4],S24,3921069994); /* 20 */
	GG(A,B,C,D,si[ 5*4],S21,3593408605); /* 21 */
	GG(D,A,B,C,si[10*4],S22,  38016083); /* 22 */
	GG(C,D,A,B,si[15*4],S23,3634488961); /* 23 */
	GG(B,C,D,A,si[ 4*4],S24,3889429448); /* 24 */
	GG(A,B,C,D,si[ 9*4],S21, 568446438); /* 25 */
	GG(D,A,B,C,si[14*4],S22,3275163606); /* 26 */
	GG(C,D,A,B,si[ 3*4],S23,4107603335); /* 27 */
	GG(B,C,D,A,si[ 8*4],S24,1163531501); /* 28 */
	GG(A,B,C,D,si[13*4],S21,2850285829); /* 29 */
	GG(D,A,B,C,si[ 2*4],S22,4243563512); /* 30 */
	GG(C,D,A,B,si[ 7*4],S23,1735328473); /* 31 */
	GG(B,C,D,A,si[12*4],S24,2368359562); /* 32 */

	/* Round 3 */
	HH(A,B,C,D,si[ 5*4],S31,4294588738); /* 33 */
	HH(D,A,B,C,si[ 8*4],S32,2272392833); /* 34 */
	HH(C,D,A,B,si[11*4],S33,1839030562); /* 35 */
	HH(B,C,D,A,si[14*4],S34,4259657740); /* 36 */
	HH(A,B,C,D,si[ 1*4],S31,2763975236); /* 37 */
	HH(D,A,B,C,si[ 4*4],S32,1272893353); /* 38 */
	HH(C,D,A,B,si[ 7*4],S33,4139469664); /* 39 */
	HH(B,C,D,A,si[10*4],S34,3200236656); /* 40 */
	HH(A,B,C,D,si[13*4],S31, 681279174); /* 41 */
	HH(D,A,B,C,si[ 0*4],S32,3936430074); /* 42 */
	HH(C,D,A,B,si[ 3*4],S33,3572445317); /* 43 */
	HH(B,C,D,A,si[ 6*4],S34,  76029189); /* 44 */
	HH(A,B,C,D,si[ 9*4],S31,3654602809); /* 45 */
	HH(D,A,B,C,si[12*4],S32,3873151461); /* 46 */
	HH(C,D,A,B,si[15*4],S33, 530742520); /* 47 */
	HH(B,C,D,A,si[ 2*4],S34,3299628645); /* 48 */

	/* Round 4 */
	II(A,B,C,D,si[ 0*4],S41,4096336452); /* 49 */
	II(D,A,B,C,si[ 7*4],S42,1126891415); /* 50 */
	II(C,D,A,B,si[14*4],S43,2878612391); /* 51 */
	II(B,C,D,A,si[ 5*4],S44,4237533241); /* 52 */
	II(A,B,C,D,si[12*4],S41,1700485571); /* 53 */
	II(D,A,B,C,si[ 3*4],S42,2399980690); /* 54 */
	II(C,D,A,B,si[10*4],S43,4293915773); /* 55 */
	II(B,C,D,A,si[ 1*4],S44,2240044497); /* 56 */
	II(A,B,C,D,si[ 8*4],S41,1873313359); /* 57 */
	II(D,A,B,C,si[15*4],S42,4264355552); /* 58 */
	II(C,D,A,B,si[ 6*4],S43,2734768916); /* 59 */
	II(B,C,D,A,si[13*4],S44,1309151649); /* 60 */
	II(A,B,C,D,si[ 4*4],S41,4149444226); /* 61 */
	II(D,A,B,C,si[11*4],S42,3174756917); /* 62 */
	II(C,D,A,B,si[ 2*4],S43, 718787259); /* 63 */
	II(B,C,D,A,si[ 9*4],S44,3951481745); /* 64 */

	pop ebp;		/* We can address our args again */

	lds si,state;		/* Update the caller's state */
	add dword ptr si[0*4],A;	/* state[0] += A */
	add dword ptr si[1*4],B;	/* state[1] += B */
	add dword ptr si[2*4],C;	/* state[2] += C */
	add dword ptr si[3*4],D;	/* state[3] += D */

	/* Restore caller's registers */
	pop ds;
	pop edi;
	pop si;
	}
}
#endif	/* CPU386 */