/* $Id: digest-sha1.c,v 1.10 2002/09/04 20:39:31 hvr Exp $
 *
 * Modified by Andrew McDonald <andrew@mcdonald.org.uk> from md5glue
 * by Alan Smithee, mailed to maintainer on pulped trees.
 *
 * Contains SHA-1 code from Steve Reid, licensed in the public domain.
 * 
 * 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, or (at your option) any
 * later version.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/crypto.h>

#include <asm/uaccess.h>
#include <asm/byteorder.h>

#ifdef MODULE_LICENSE
MODULE_LICENSE("GPL");
#endif /* MODULE_LICENSE */
#ifdef MODULE_DESCRIPTION
MODULE_DESCRIPTION ("SHA1 Digest / CryptoAPI");
#endif

#define SHA1HANDSOFF /* Copies data before messing with it. */

struct SHA1_CTX {
	unsigned long state[5];
	unsigned long count[2];
	unsigned char buffer[64];
};

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#if defined(__LITTLE_ENDIAN)
# define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
    |(rol(block->l[i],8)&0x00FF00FF))
#elif defined (__BIG_ENDIAN)
# define blk0(i) block->l[i]
#else
# error fix <asm/byteorder.h>
#endif /* _ENDIAN */

#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5); \
                        w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5); \
                        w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5); \
                        w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */
static void
SHA1Transform(unsigned long state[5], const unsigned char buffer[64])
{
	unsigned long a, b, c, d, e;
	typedef union {
		unsigned char c[64];
		unsigned long l[16];
	} CHAR64LONG16;
	CHAR64LONG16* block;
#ifdef SHA1HANDSOFF
	static unsigned char workspace[64];
	block = (CHAR64LONG16*)workspace;
	memcpy(block, buffer, 64);
#else
	block = (CHAR64LONG16*)buffer;
#endif
	/* Copy context->state[] to working vars */
	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	/* 4 rounds of 20 operations each. Loop unrolled. */
	R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
	R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
	R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
	R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
	R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
	R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
	R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
	R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
	R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
	R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
	R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
	R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
	R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
	R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
	R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
	R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
	R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
	R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
	R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
	R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
	/* Add the working vars back into context.state[] */
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	/* Wipe variables */
	a = b = c = d = e = 0;
}

/* SHA1Init - Initialize new context */
static void SHA1Init(struct SHA1_CTX* context)
{
	/* SHA1 initialization constants */
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
	context->state[4] = 0xC3D2E1F0;
	context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */
static void
SHA1Update(struct SHA1_CTX* context, const unsigned char* data,
	   unsigned int len)
{
	unsigned int i, j;

	j = (context->count[0] >> 3) & 63;
	if ((context->count[0] += len << 3) < (len << 3)) context->count[1]++;
	context->count[1] += (len >> 29);
	if ((j + len) > 63) {
		memcpy(&context->buffer[j], data, (i = 64-j));
		SHA1Transform(context->state, context->buffer);
		for ( ; i + 63 < len; i += 64) {
			SHA1Transform(context->state, &data[i]);
		}
		j = 0;
	}
	else i = 0;
	memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */
static void
SHA1Final(unsigned char digest[20], struct SHA1_CTX* context)
{
	unsigned long i, j;
	unsigned char finalcount[8];

	for (i = 0; i < 8; i++) {
		finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)] >> ((3-(i & 3)) * 8) ) & 255); /* Endian independent */
	}
	SHA1Update(context, (unsigned char *)"\200", 1);
	while ((context->count[0] & 504) != 448) {
		SHA1Update(context, (unsigned char *)"\0", 1);
	}
	SHA1Update(context, finalcount, 8); /* Should cause SHA1Transform() */

	for (i = 0; i < 20; i++) {
		digest[i] = (unsigned char)
			((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
	}

	/* Wipe variables */
	i = j = 0;
	memset(context->buffer, 0, 64);
	memset(context->state, 0, 20);
	memset(context->count, 0, 8);
	memset(&finalcount, 0, 8);
#ifdef SHA1HANDSOFF  /* make SHA1Transform overwrite it's own static vars */
	SHA1Transform(context->state, context->buffer);
#endif
}

static int
sha1_open(struct digest_context *cx, int atomic)
{
	if (!cx || !cx->digest_info)
		return -EINVAL;

	SHA1Init ((struct SHA1_CTX *) cx->digest_info);

	return 0;
}

static int
sha1_update(struct digest_context *cx, const u8 *in, int size, int atomic)
{
	if (!cx || !in || !cx->digest_info)
		return -EINVAL;

	SHA1Update ((struct SHA1_CTX *) cx->digest_info, in, size);

	return 0;
}

static int
sha1_digest(struct digest_context *cx, u8 *out, int atomic)
{
	struct SHA1_CTX tmp;

	if (!cx || !out || !cx->digest_info)
		return -EINVAL;

	memcpy (&tmp, (struct SHA1_CTX *) cx->digest_info, 
		sizeof (struct SHA1_CTX));
	SHA1Final (out, &tmp);

	return 0;
}

static int
sha1_close(struct digest_context *cx, u8 *out, int atomic)
{
	u8 tmp[16];

	if (!cx || !cx->digest_info)
		return -EINVAL;
	
	if (out == 0)
		out = tmp;

	SHA1Final (out, (struct SHA1_CTX *) cx->digest_info);

	return 0;
}

#define DIGEST_ID		sha1
#define DIGEST_SIZE		sizeof (struct SHA1_CTX)
#define DIGEST_BLOCKSIZE	20

#include "gen-hash.h"

EXPORT_NO_SYMBOLS;
