/*

  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************

 * Copyright (C) Miroslav Lichvar  2012

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 * 

 * 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 the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 * 

 **********************************************************************

  =======================================================================

  Routines implementing crypto hashing using NSSLOWHASH API of the NSS library.

  */

#include "config.h"

#include <nss.h>

#include <hasht.h>

#include <nsslowhash.h>

#include "hash.h"

#include "util.h"

static NSSLOWInitContext *ictx;

struct hash {

  HASH_HashType type;

  const char *name;

  NSSLOWHASHContext *context;

};

static struct hash hashes[] = {

  { HASH_AlgMD5, "MD5", NULL },

  { HASH_AlgSHA1, "SHA1", NULL },

  { HASH_AlgSHA256, "SHA256", NULL },

  { HASH_AlgSHA384, "SHA384", NULL },

  { HASH_AlgSHA512, "SHA512", NULL },

  { 0, NULL, NULL }

};

int

HSH_GetHashId(const char *name)

{

  int i;

  for (i = 0; hashes[i].name; i++) {

    if (!strcmp(name, hashes[i].name))

      break;

  }

  if (!hashes[i].name)

    return -1; /* not found */

  if (!ictx && !(ictx = NSSLOW_Init()))

    return -1; /* couldn't init NSS */

  if (!hashes[i].context &&

      !(hashes[i].context = NSSLOWHASH_NewContext(ictx, hashes[i].type)))

    return -1; /* couldn't init hash */

  return i;

}

unsigned int

HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,

    const unsigned char *in2, unsigned int in2_len,

    unsigned char *out, unsigned int out_len)

{

  unsigned char buf[MAX_HASH_LENGTH];

  unsigned int ret = 0;

  NSSLOWHASH_Begin(hashes[id].context);

  NSSLOWHASH_Update(hashes[id].context, in1, in1_len);

  if (in2)

    NSSLOWHASH_Update(hashes[id].context, in2, in2_len);

  NSSLOWHASH_End(hashes[id].context, buf, &ret, sizeof (buf));

  ret = MIN(ret, out_len);

  memcpy(out, buf, ret);

  return ret;

}

void

HSH_Finalise(void)

{

  int i;

  for (i = 0; hashes[i].name; i++) {

    if (hashes[i].context)

      NSSLOWHASH_Destroy(hashes[i].context);

  }

  if (ictx)

    NSSLOW_Shutdown(ictx);

}