/*
 * MD4 hash implementation
 * 
 * This software may be distributed under the terms of BSD license.
 */

#include "utils/includes.h"
#include "utils/common.h"
#include "crypto.h"

#define MD4_BLOCK_LENGTH	64
#define MD4_DIGEST_LENGTH	16

typedef struct MD4Context {
	u32 state[4];
	u64 count;
	u8 buffer[MD4_BLOCK_LENGTH];
} MD4_CTX;

static void MD4Init(MD4_CTX *ctx);
static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len);
static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx);

int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
	MD4_CTX ctx;
	size_t i;

	MD4Init(&ctx);
	for (i = 0; i < num_elem; i++)
		MD4Update(&ctx, addr[i], len[i]);
	MD4Final(mac, &ctx);
	return 0;
}

#define MD4_DIGEST_STRING_LENGTH	(MD4_DIGEST_LENGTH * 2 + 1)

static void MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);

#define PUT_64BIT_LE(cp, value) do {	\
	(cp)[7] = (value) >> 56;	\
	(cp)[6] = (value) >> 48;	\
	(cp)[5] = (value) >> 40;	\
	(cp)[4] = (value) >> 32;	\
	(cp)[3] = (value) >> 24;	\
	(cp)[2] = (value) >> 16;	\
	(cp)[1] = (value) >> 8;		\
	(cp)[0] = (value); } while (0)

#define PUT_32BIT_LE(cp, value) do {	\
	(cp)[3] = (value) >> 24;	\
	(cp)[2] = (value) >> 16;	\
	(cp)[1] = (value) >> 8;		\
	(cp)[0] = (value); } while (0)

static u8 PADDING[MD4_BLOCK_LENGTH] = {
	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
};

static void MD4Init(MD4_CTX *ctx)
{
	ctx->count = 0;
	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xefcdab89;
	ctx->state[2] = 0x98badcfe;
	ctx->state[3] = 0x10325476;
}

static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len)
{
	size_t have, need;

	have = (size_t)((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
	need = MD4_BLOCK_LENGTH - have;

	ctx->count += (u64)len << 3;

	if (len >= need) {
		if (have != 0) {
			os_memcpy(ctx->buffer + have, input, need);
			MD4Transform(ctx->state, ctx->buffer);
			input += need;
			len -= need;
			have = 0;
		}

		while (len >= MD4_BLOCK_LENGTH) {
			MD4Transform(ctx->state, input);
			input += MD4_BLOCK_LENGTH;
			len -= MD4_BLOCK_LENGTH;
		}
	}

	if (len != 0)
		os_memcpy(ctx->buffer + have, input, len);
}

static void MD4Pad(MD4_CTX *ctx)
{
	u8 count[8];
	size_t padlen;

	PUT_64BIT_LE(count, ctx->count);

	padlen = MD4_BLOCK_LENGTH -
		((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
	if (padlen < 1 + 8)
		padlen += MD4_BLOCK_LENGTH;
	MD4Update(ctx, PADDING, padlen - 8);
	MD4Update(ctx, count, 8);
}

static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx)
{
	int i;

	MD4Pad(ctx);
	if (digest != NULL) {
		for (i = 0; i < 4; i ++)
			PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
		os_memset(ctx, 0, sizeof(*ctx));
	}
}

#define F1(x, y, z)	(z ^ (x & (y ^ z)))
#define F2(x, y, z)	((x & y) | (x & z) | (y & z))
#define F3(x, y, z)	(x ^ y ^ z)

#define MD4SETP(f, w, x, y, z, data, s)	\
	( w += f(x, y, z) + data, w = w<<s | w>>(32-s) )

static void MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH])
{
	u32 a, b, c, d, in[MD4_BLOCK_LENGTH / 4];

	os_memcpy(in, block, sizeof(in));

	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];

	MD4SETP(F1, a, b, c, d, in[ 0], 3);
	MD4SETP(F1, d, a, b, c, in[ 1], 7);
	MD4SETP(F1, c, d, a, b, in[ 2], 11);
	MD4SETP(F1, b, c, d, a, in[ 3], 19);
	MD4SETP(F1, a, b, c, d, in[ 4], 3);
	MD4SETP(F1, d, a, b, c, in[ 5], 7);
	MD4SETP(F1, c, d, a, b, in[ 6], 11);
	MD4SETP(F1, b, c, d, a, in[ 7], 19);
	MD4SETP(F1, a, b, c, d, in[ 8], 3);
	MD4SETP(F1, d, a, b, c, in[ 9], 7);
	MD4SETP(F1, c, d, a, b, in[10], 11);
	MD4SETP(F1, b, c, d, a, in[11], 19);
	MD4SETP(F1, a, b, c, d, in[12], 3);
	MD4SETP(F1, d, a, b, c, in[13], 7);
	MD4SETP(F1, c, d, a, b, in[14], 11);
	MD4SETP(F1, b, c, d, a, in[15], 19);

	MD4SETP(F2, a, b, c, d, in[ 0] + 0x5a827999, 3);
	MD4SETP(F2, d, a, b, c, in[ 4] + 0x5a827999, 5);
	MD4SETP(F2, c, d, a, b, in[ 8] + 0x5a827999, 9);
	MD4SETP(F2, b, c, d, a, in[12] + 0x5a827999, 13);
	MD4SETP(F2, a, b, c, d, in[ 1] + 0x5a827999, 3);
	MD4SETP(F2, d, a, b, c, in[ 5] + 0x5a827999, 5);
	MD4SETP(F2, c, d, a, b, in[ 9] + 0x5a827999, 9);
	MD4SETP(F2, b, c, d, a, in[13] + 0x5a827999, 13);
	MD4SETP(F2, a, b, c, d, in[ 2] + 0x5a827999, 3);
	MD4SETP(F2, d, a, b, c, in[ 6] + 0x5a827999, 5);
	MD4SETP(F2, c, d, a, b, in[10] + 0x5a827999, 9);
	MD4SETP(F2, b, c, d, a, in[14] + 0x5a827999, 13);
	MD4SETP(F2, a, b, c, d, in[ 3] + 0x5a827999, 3);
	MD4SETP(F2, d, a, b, c, in[ 7] + 0x5a827999, 5);
	MD4SETP(F2, c, d, a, b, in[11] + 0x5a827999, 9);
	MD4SETP(F2, b, c, d, a, in[15] + 0x5a827999, 13);

	MD4SETP(F3, a, b, c, d, in[ 0] + 0x6ed9eba1,  3);
	MD4SETP(F3, d, a, b, c, in[ 8] + 0x6ed9eba1,  9);
	MD4SETP(F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
	MD4SETP(F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
	MD4SETP(F3, a, b, c, d, in[ 2] + 0x6ed9eba1,  3);
	MD4SETP(F3, d, a, b, c, in[10] + 0x6ed9eba1,  9);
	MD4SETP(F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
	MD4SETP(F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
	MD4SETP(F3, a, b, c, d, in[ 1] + 0x6ed9eba1,  3);
	MD4SETP(F3, d, a, b, c, in[ 9] + 0x6ed9eba1,  9);
	MD4SETP(F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
	MD4SETP(F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
	MD4SETP(F3, a, b, c, d, in[ 3] + 0x6ed9eba1,  3);
	MD4SETP(F3, d, a, b, c, in[11] + 0x6ed9eba1,  9);
	MD4SETP(F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
	MD4SETP(F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
}