/*
 * ZMap Copyright 2013 Regents of the University of Michigan
 *
 * 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
 */

#include <stdint.h>
#include <assert.h>
#include "../lib/rijndael-alg-fst.h"
#include "../lib/random.h"
#include "../lib/logger.h"
#include "validate.h"

#define AES_ROUNDS 10
#define AES_BLOCK_WORDS	4
#define AES_KEY_BYTES 16

static int inited = 0;
static uint32_t aes_input[AES_BLOCK_WORDS];
static uint32_t aes_sched[(AES_ROUNDS+1)*4];

void validate_init()
{
	for (int i=0; i < AES_BLOCK_WORDS; i++) {
		aes_input[i] = 0;
	}
	uint8_t key[AES_KEY_BYTES];
	if (!random_bytes(key, AES_KEY_BYTES)) {
		log_fatal("validate", "couldn't get random bytes");
	}
	if (rijndaelKeySetupEnc(aes_sched, key, AES_KEY_BYTES*8) != AES_ROUNDS) {
		log_fatal("validate", "couldn't initialize AES key");
	}
	inited = 1;
}

void validate_gen(const uint32_t src, const uint32_t dst,
				uint8_t output[VALIDATE_BYTES])
{
	assert(inited);
	aes_input[0] = src;
	aes_input[1] = dst;
	rijndaelEncrypt(aes_sched, AES_ROUNDS, (uint8_t *)aes_input, output);
}