/* fat-arm.c

   Copyright (C) 2015 Niels Möller

   This file is part of GNU Nettle.

   GNU Nettle is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.

   GNU Nettle 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 copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see http://www.gnu.org/licenses/.
*/

#define _GNU_SOURCE

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "nettle-types.h"

#include "aes-internal.h"
#include "fat-setup.h"

struct arm_features
{
  /* /proc/cpuinfo "CPU Architecture" doesn't correspond exactly to
     ARM architecture version, but it's good enough for our purposes.
     Will be set to 5, 6, 7 or 8. */
  unsigned arch_version;
  int have_neon;
};

#define SKIP(s, slen, literal, llen)				\
  (((slen) >= (llen) && memcmp ((s), (literal), llen) == 0)	\
   ? ((slen) -= (llen), (s) += (llen), 1) : 0)
#define MATCH(s, slen, literal, llen)				\
  ((slen) == (llen) && memcmp ((s), (literal), llen) == 0)

static void
get_arm_features (struct arm_features *features)
{
  const char *s;
  features->arch_version = 5;
  features->have_neon = 0;

  s = secure_getenv (ENV_OVERRIDE);
  if (s)
    for (;;)
      {
	const char *sep = strchr (s, ',');
	size_t length = sep ? (size_t) (sep - s) : strlen(s);

	if (SKIP (s, length, "arch:", 5))
	  {
	    if (length == 1 && *s >= '0' && *s <= '9')
	      features->arch_version = *s - '0';
	  }
	else if (MATCH (s, length, "neon", 4))
	  features->have_neon = 1;
	if (!sep)
	  break;
	s = sep + 1;
      }
  else
    {
      FILE *f;
      char line[200];
      int seen_arch = 0;
      int seen_features = 0;

      f = fopen ("/proc/cpuinfo", "r");
      if (!f)
	return;
      while (seen_features + seen_arch < 2
	     && fgets (line, sizeof(line), f))
	{
	  char *sep;
	  char *p;
	  sep = strchr (line, ':');
	  if (!sep)
	    continue;
	  for (p = sep; p - line > 0 && p[-1] == '\t'; p--)
	    ;

	  *p = '\0';
	  p = sep+1;

	  if (strcmp (line, "Features") == 0)
	    {
	      features->have_neon = (strstr (p, " neon ") != NULL);
	      seen_features = 1;
	    }
	  else if (strcmp (line, "CPU architecture") == 0)
	    {
	      /* Don't use strtol, since it's locale dependent. */
	      while (p[0] == ' ')
		p++;
	      if (p[0] > '5' && p[0] <= '9')
		features->arch_version = p[0] - '0';
	      else if (strcmp (p, "AArch64") == 0)
		features->arch_version = 8;
	      seen_arch = 1;
	    }
	}
      if (features->arch_version >= 8)
	{
	  /* Neon is not required, and maybe not listed in feature flags */
	  features->have_neon = 1;
	}
      fclose (f);
    }
}

DECLARE_FAT_FUNC(_nettle_aes_encrypt, aes_crypt_internal_func)
DECLARE_FAT_FUNC_VAR(aes_encrypt, aes_crypt_internal_func, arm)
DECLARE_FAT_FUNC_VAR(aes_encrypt, aes_crypt_internal_func, armv6)

DECLARE_FAT_FUNC(_nettle_aes_decrypt, aes_crypt_internal_func)
DECLARE_FAT_FUNC_VAR(aes_decrypt, aes_crypt_internal_func, arm)
DECLARE_FAT_FUNC_VAR(aes_decrypt, aes_crypt_internal_func, armv6)

DECLARE_FAT_FUNC(_nettle_salsa20_core, salsa20_core_func)
DECLARE_FAT_FUNC_VAR(salsa20_core, salsa20_core_func, c)
DECLARE_FAT_FUNC_VAR(salsa20_core, salsa20_core_func, neon)

DECLARE_FAT_FUNC(nettle_sha1_compress, sha1_compress_func)
DECLARE_FAT_FUNC_VAR(sha1_compress, sha1_compress_func, c)
DECLARE_FAT_FUNC_VAR(sha1_compress, sha1_compress_func, armv6)

DECLARE_FAT_FUNC(_nettle_sha256_compress, sha256_compress_func)
DECLARE_FAT_FUNC_VAR(sha256_compress, sha256_compress_func, c)
DECLARE_FAT_FUNC_VAR(sha256_compress, sha256_compress_func, armv6)

DECLARE_FAT_FUNC(_nettle_sha512_compress, sha512_compress_func)
DECLARE_FAT_FUNC_VAR(sha512_compress, sha512_compress_func, c)
DECLARE_FAT_FUNC_VAR(sha512_compress, sha512_compress_func, neon)

DECLARE_FAT_FUNC(nettle_sha3_permute, sha3_permute_func)
DECLARE_FAT_FUNC_VAR(sha3_permute, sha3_permute_func, c)
DECLARE_FAT_FUNC_VAR(sha3_permute, sha3_permute_func, neon)

DECLARE_FAT_FUNC(_nettle_umac_nh, umac_nh_func)
DECLARE_FAT_FUNC_VAR(umac_nh, umac_nh_func, c);
DECLARE_FAT_FUNC_VAR(umac_nh, umac_nh_func, neon);

DECLARE_FAT_FUNC(_nettle_umac_nh_n, umac_nh_n_func)
DECLARE_FAT_FUNC_VAR(umac_nh_n, umac_nh_n_func, c);
DECLARE_FAT_FUNC_VAR(umac_nh_n, umac_nh_n_func, neon);

DECLARE_FAT_FUNC(_nettle_chacha_core, chacha_core_func)
DECLARE_FAT_FUNC_VAR(chacha_core, chacha_core_func, c);
DECLARE_FAT_FUNC_VAR(chacha_core, chacha_core_func, neon);

static void CONSTRUCTOR
fat_init (void)
{
  struct arm_features features;
  int verbose;

  get_arm_features (&features);

  verbose = getenv (ENV_VERBOSE) != NULL;
  if (verbose)
    fprintf (stderr, "libnettle: cpu features: arch:%d%s\n",
	     features.arch_version,
	     features.have_neon ? ",neon" : "");

  if (features.arch_version >= 6)
    {
      if (verbose)
	fprintf (stderr, "libnettle: enabling armv6 code.\n");
      _nettle_aes_encrypt_vec = _nettle_aes_encrypt_armv6;
      _nettle_aes_decrypt_vec = _nettle_aes_decrypt_armv6;
      nettle_sha1_compress_vec = _nettle_sha1_compress_armv6;
      _nettle_sha256_compress_vec = _nettle_sha256_compress_armv6;
    }
  else
    {
      if (verbose)
	fprintf (stderr, "libnettle: not enabling armv6 code.\n");
      _nettle_aes_encrypt_vec = _nettle_aes_encrypt_arm;
      _nettle_aes_decrypt_vec = _nettle_aes_decrypt_arm;
      nettle_sha1_compress_vec = _nettle_sha1_compress_c;
      _nettle_sha256_compress_vec = _nettle_sha256_compress_c;
    }
  if (features.have_neon)
    {
      if (verbose)
	fprintf (stderr, "libnettle: enabling neon code.\n");
      _nettle_salsa20_core_vec = _nettle_salsa20_core_neon;
      _nettle_sha512_compress_vec = _nettle_sha512_compress_neon;
      nettle_sha3_permute_vec = _nettle_sha3_permute_neon;
      _nettle_umac_nh_vec = _nettle_umac_nh_neon;
      _nettle_umac_nh_n_vec = _nettle_umac_nh_n_neon;
      _nettle_chacha_core_vec = _nettle_chacha_core_neon;
    }
  else
    {
      if (verbose)
	fprintf (stderr, "libnettle: not enabling neon code.\n");
      _nettle_salsa20_core_vec = _nettle_salsa20_core_c;
      _nettle_sha512_compress_vec = _nettle_sha512_compress_c;
      nettle_sha3_permute_vec = _nettle_sha3_permute_c;
      _nettle_umac_nh_vec = _nettle_umac_nh_c;
      _nettle_umac_nh_n_vec = _nettle_umac_nh_n_c;
      _nettle_chacha_core_vec = _nettle_chacha_core_c;
    }
}
  
DEFINE_FAT_FUNC(_nettle_aes_encrypt, void,
		(unsigned rounds, const uint32_t *keys,
		 const struct aes_table *T,
		 size_t length, uint8_t *dst,
		 const uint8_t *src),
		(rounds, keys, T, length, dst, src))

DEFINE_FAT_FUNC(_nettle_aes_decrypt, void,
		(unsigned rounds, const uint32_t *keys,
		 const struct aes_table *T,
		 size_t length, uint8_t *dst,
		 const uint8_t *src),
		(rounds, keys, T, length, dst, src))

DEFINE_FAT_FUNC(_nettle_salsa20_core, void,
		(uint32_t *dst, const uint32_t *src, unsigned rounds),
		(dst, src, rounds))

DEFINE_FAT_FUNC(nettle_sha1_compress, void,
		(uint32_t *state, const uint8_t *input),
		(state, input))

DEFINE_FAT_FUNC(_nettle_sha256_compress, void,
		(uint32_t *state, const uint8_t *input, const uint32_t *k),
		(state, input, k))

DEFINE_FAT_FUNC(_nettle_sha512_compress, void,
		(uint64_t *state, const uint8_t *input, const uint64_t *k),
		(state, input, k))

DEFINE_FAT_FUNC(nettle_sha3_permute, void,
		(struct sha3_state *state), (state))

DEFINE_FAT_FUNC(_nettle_umac_nh, uint64_t,
		(const uint32_t *key, unsigned length, const uint8_t *msg),
		(key, length, msg))

DEFINE_FAT_FUNC(_nettle_umac_nh_n, void,
		(uint64_t *out, unsigned n, const uint32_t *key,
		 unsigned length, const uint8_t *msg),
		(out, n, key, length, msg))

DEFINE_FAT_FUNC(_nettle_chacha_core, void,
		(uint32_t *dst, const uint32_t *src, unsigned rounds),
		(dst, src, rounds))