/*-
 * Copyright 2016 Vsevolod Stakhov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "config.h"
#include "cryptobox.h"
#include "siphash.h"
#include "platform_config.h"
#include "ottery.h"
#include <stdbool.h>

extern unsigned long cpu_config;

typedef struct siphash_impl_t
{
	unsigned long cpu_flags;
	const char *desc;

	uint64_t (*siphash) (const unsigned char k[16], const unsigned char *in, const uint64_t inlen);
} siphash_impl_t;

#define SIPHASH_DECLARE(ext) \
	uint64_t siphash_##ext(const unsigned char k[16], const unsigned char *in, const uint64_t inlen);

#define SIPHASH_IMPL(cpuflags, desc, ext) \
	{(cpuflags), desc, siphash_##ext}


SIPHASH_DECLARE(ref)
#define SIPHASH_GENERIC SIPHASH_IMPL(0, "generic", ref)
#if defined(HAVE_SSE41) && defined(__i386__)
SIPHASH_DECLARE(sse41)
#define SIPHASH_SSE41 SIPHASH_IMPL(CPUID_SSE41, "sse41", sse41)
#endif
#if defined(HAVE_AVX2) && defined(__x86_64__)
SIPHASH_DECLARE(avx2)
#define SIPHASH_AVX2 SIPHASH_IMPL(CPUID_AVX2, "avx2", avx2)
#endif

/* list implemenations from most optimized to least, with generic as the last entry */
static const siphash_impl_t siphash_list[] = {
		SIPHASH_GENERIC,
#if defined(SIPHASH_AVX2)
		SIPHASH_AVX2,
#endif
#if defined(SIPHASH_SSE41)
		SIPHASH_SSE41,
#endif
};

static const siphash_impl_t *siphash_opt = &siphash_list[0];

static bool
siphash_test_impl (const siphash_impl_t *impl)
{
	static const unsigned char vectors[64][8] = {
			{ 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, },
			{ 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, },
			{ 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d, },
			{ 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85, },
			{ 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf, },
			{ 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18, },
			{ 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb, },
			{ 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab, },
			{ 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93, },
			{ 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e, },
			{ 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a, },
			{ 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4, },
			{ 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75, },
			{ 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14, },
			{ 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7, },
			{ 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1, },
			{ 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f, },
			{ 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69, },
			{ 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b, },
			{ 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb, },
			{ 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe, },
			{ 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0, },
			{ 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93, },
			{ 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8, },
			{ 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8, },
			{ 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc, },
			{ 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17, },
			{ 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f, },
			{ 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde, },
			{ 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6, },
			{ 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad, },
			{ 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32, },
			{ 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71, },
			{ 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7, },
			{ 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12, },
			{ 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15, },
			{ 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31, },
			{ 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02, },
			{ 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca, },
			{ 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a, },
			{ 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e, },
			{ 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad, },
			{ 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18, },
			{ 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4, },
			{ 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9, },
			{ 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9, },
			{ 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb, },
			{ 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0, },
			{ 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6, },
			{ 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7, },
			{ 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee, },
			{ 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1, },
			{ 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a, },
			{ 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81, },
			{ 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f, },
			{ 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24, },
			{ 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7, },
			{ 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea, },
			{ 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60, },
			{ 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66, },
			{ 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c, },
			{ 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f, },
			{ 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5, },
			{ 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95, }
	};
	unsigned char in[64];
	static const unsigned char k[] ={
			'\000', '\001', '\002', '\003', '\004',
			'\005', '\006', '\007', '\010', '\011',
			'\012', '\013', '\014', '\015', '\016', '\017'
	};
	size_t i;
	union {
		guint64 m;
		guchar c[sizeof (guint64)];
	} r;

	for (i = 0; i < sizeof in; ++i) {
		in[i] = i;
		r.m = impl->siphash (k, in, i);

		if (memcmp (r.c, vectors[i], sizeof (r)) != 0) {
			return false;
		}
	}

	return true;
}

const char *
siphash_load(void)
{
	guint i;

	if (cpu_config != 0) {
		for (i = 0; i < G_N_ELEMENTS(siphash_list); i++) {
			if (siphash_list[i].cpu_flags & cpu_config) {
				siphash_opt = &siphash_list[i];
				g_assert (siphash_test_impl (siphash_opt));
				break;
			}
		}
	}

	return siphash_opt->desc;
}

void siphash24 (unsigned char *out, const unsigned char *in,
		unsigned long long inlen, const unsigned char *k)
{
	uint64_t r;

	r = siphash_opt->siphash (k, in, inlen);
	memcpy (out, &r, sizeof (r));
}


size_t
siphash24_test (bool generic, size_t niters, size_t len)
{
	size_t cycles;
	guchar *in, k[16];
	const siphash_impl_t *impl;

	g_assert (len > 0);
	in = g_malloc (len);
	ottery_rand_bytes (k, sizeof (k));
	ottery_rand_bytes (in, len);

	impl = generic ? &siphash_list[0] : siphash_opt;

	for (cycles = 0; cycles < niters; cycles ++) {
		impl->siphash (k, in, len);
	}

	return cycles;
}

bool
siphash24_fuzz (size_t cycles)
{
	size_t i, len;
	guint64 t, r;
	guchar in[8192], k[16];

	for (i = 0; i < cycles; i ++) {
		ottery_rand_bytes (k, sizeof (k));
		len = ottery_rand_range (sizeof (in) - 1);
		ottery_rand_bytes (in, len);

		t = siphash_list[0].siphash (k, in, len);
		r = siphash_opt->siphash (k, in, len);

		if (t != r) {
			return false;
		}
	}

	return true;
}
