/*
  Copyright (c) 2012-2013, Matthias Schiffer <mschiffer@universe-factory.net>
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include "fastd.h"
#include "crypto.h"


#ifdef USE_CRYPTO_AES128CTR
#ifdef WITH_CRYPTO_AES128CTR_NACL

#include <crypto_stream_aes128ctr.h>


struct fastd_crypto_aes128ctr_state {
	fastd_buffer_t d;
};


static fastd_crypto_aes128ctr_context_t* aes128ctr_init(fastd_context_t *ctx UNUSED) {
	return (fastd_crypto_aes128ctr_context_t*)1;
}

static fastd_crypto_aes128ctr_state_t* aes128ctr_set_key(fastd_context_t *ctx, const fastd_crypto_aes128ctr_context_t *cctx UNUSED, const fastd_block128_t *key) {
	fastd_crypto_aes128ctr_state_t *cstate = malloc(sizeof(fastd_crypto_aes128ctr_state_t));

	cstate->d = fastd_buffer_alloc(ctx, crypto_stream_aes128ctr_BEFORENMBYTES, 0, 0);
	crypto_stream_aes128ctr_beforenm(cstate->d.data, key->b);

	return cstate;
}

static bool aes128ctr_crypt(fastd_context_t *ctx UNUSED, const fastd_crypto_aes128ctr_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t len, const fastd_block128_t *iv) {
	crypto_stream_aes128ctr_xor_afternm(out->b, in->b, len, iv->b, cstate->d.data);
	return true;
}

static void aes128ctr_free_state(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_state_t *cstate) {
	if (cstate) {
		fastd_buffer_free(cstate->d);
		free(cstate);
	}
}

static void aes128ctr_free(fastd_context_t *ctx UNUSED, fastd_crypto_aes128ctr_context_t *cctx UNUSED) {
}

const fastd_crypto_aes128ctr_t fastd_crypto_aes128ctr_nacl = {
	.name = "nacl",

	.init = aes128ctr_init,
	.set_key = aes128ctr_set_key,
	.crypt = aes128ctr_crypt,

	.free_state = aes128ctr_free_state,
	.free = aes128ctr_free,
};

#endif
#endif

#ifdef USE_CRYPTO_GHASH
#ifdef WITH_CRYPTO_GHASH_BUILTIN

struct fastd_crypto_ghash_state {
	fastd_block128_t H[32][16];
};


static const fastd_block128_t r = { .b = {0xe1} };


static inline uint8_t shr(fastd_block128_t *out, const fastd_block128_t *in, int n) {
	size_t i;
	uint8_t c = 0;

	for (i = 0; i < sizeof(fastd_block128_t); i++) {
		uint8_t c2 = in->b[i] << (8-n);
		out->b[i] = (in->b[i] >> n) | c;
		c = c2;
	}

	return (c >> (8-n));
}

static inline void mulH_a(fastd_block128_t *x, const fastd_crypto_ghash_state_t *cstate) {
	fastd_block128_t out = {};

	int i;
	for (i = 0; i < 16; i++) {
		xor_a(&out, &cstate->H[2*i][x->b[i]>>4]);
		xor_a(&out, &cstate->H[2*i+1][x->b[i]&0xf]);
	}

	*x = out;
}


static fastd_crypto_ghash_context_t* ghash_init(fastd_context_t *ctx UNUSED) {
	return (fastd_crypto_ghash_context_t*)1;
}

static fastd_crypto_ghash_state_t* ghash_set_h(fastd_context_t *ctx UNUSED, const fastd_crypto_ghash_context_t *cctx UNUSED, const fastd_block128_t *h) {
	fastd_crypto_ghash_state_t *cstate = malloc(sizeof(fastd_crypto_ghash_state_t));

	fastd_block128_t Hbase[4];
	fastd_block128_t Rbase[4];

	Hbase[0] = *h;
	Rbase[0] = r;

	int i;
	for (i = 1; i < 4; i++) {
		uint8_t carry = shr(&Hbase[i], &Hbase[i-1], 1);
		if (carry)
			xor_a(&Hbase[i], &r);

		shr(&Rbase[i], &Rbase[i-1], 1);
	}

	fastd_block128_t R[16];
	memset(cstate->H, 0, sizeof(cstate->H));
	memset(R, 0, sizeof(R));

	for (i = 0; i < 16; i++) {
		int j;
		for (j = 0; j < 4; j++) {
			if (i & (8 >> j)) {
				xor_a(&cstate->H[0][i], &Hbase[j]);
				xor_a(&R[i], &Rbase[j]);
			}
		}
	}

	for (i = 1; i < 32; i++) {
		int j;

		for (j = 0; j < 16; j++) {
			uint8_t carry = shr(&cstate->H[i][j], &cstate->H[i-1][j], 4);
			xor_a(&cstate->H[i][j], &R[carry]);
		}
	}

	return cstate;
}

static bool ghash_hash(fastd_context_t *ctx UNUSED, const fastd_crypto_ghash_state_t *cstate, fastd_block128_t *out, const fastd_block128_t *in, size_t n_blocks) {
	memset(out, 0, sizeof(fastd_block128_t));

	size_t i;
	for (i = 0; i < n_blocks; i++) {
		xor_a(out, &in[i]);
		mulH_a(out, cstate);
	}

	return true;
}

static void ghash_free_state(fastd_context_t *ctx UNUSED, fastd_crypto_ghash_state_t *cstate) {
	free(cstate);
}

static void ghash_free(fastd_context_t *ctx UNUSED, fastd_crypto_ghash_context_t *cctx UNUSED) {
}

const fastd_crypto_ghash_t fastd_crypto_ghash_builtin = {
	.name = "builtin",

	.init = ghash_init,
	.set_h = ghash_set_h,
	.hash = ghash_hash,

	.free_state = ghash_free_state,
	.free = ghash_free,
};

#endif
#endif