/*
 * Copyright (c) 2015 Mike Belopuhov
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef _CHACHAPOLY_H_
#define _CHACHAPOLY_H_

#define CHACHA20_KEYSIZE	32
#define CHACHA20_CTR		4
#define CHACHA20_SALT		4
#define CHACHA20_NONCE		8
#define CHACHA20_BLOCK_LEN	64

struct chacha20_ctx {
	uint8_t			block[CHACHA20_BLOCK_LEN];
	uint8_t			nonce[CHACHA20_NONCE];
};

int	chacha20_setkey(void *, u_int8_t *, int);
void	chacha20_reinit(caddr_t, u_int8_t *);
void	chacha20_crypt(caddr_t, u_int8_t *);


#define POLY1305_KEYLEN		32
#define POLY1305_TAGLEN		16
#define POLY1305_BLOCK_LEN	16

struct poly1305_ctx {
	/* r, h, pad, leftover */
	unsigned long		state[5+5+4];
	size_t			leftover;
	unsigned char		buffer[POLY1305_BLOCK_LEN];
	unsigned char		final;
};

typedef struct {
	uint8_t			key[POLY1305_KEYLEN];
	/* counter, salt */
	uint8_t			nonce[CHACHA20_NONCE];
	struct chacha20_ctx	chacha;
	struct poly1305_ctx	poly;
} CHACHA20_POLY1305_CTX;

void	Chacha20_Poly1305_Init(void *);
void	Chacha20_Poly1305_Setkey(void *, const uint8_t *, uint16_t);
void	Chacha20_Poly1305_Reinit(void *, const uint8_t *, uint16_t);
int	Chacha20_Poly1305_Update(void *, const uint8_t *, uint16_t);
void	Chacha20_Poly1305_Final(uint8_t[POLY1305_TAGLEN], void *);

/* WireGuard crypto */
#define CHACHA20POLY1305_KEY_SIZE	CHACHA20_KEYSIZE
#define CHACHA20POLY1305_AUTHTAG_SIZE	POLY1305_TAGLEN
#define XCHACHA20POLY1305_NONCE_SIZE	24

void chacha20poly1305_encrypt(uint8_t *, const uint8_t *, const size_t,
	const uint8_t *, const size_t,	const uint64_t,
	const uint8_t[CHACHA20POLY1305_KEY_SIZE]);

int chacha20poly1305_decrypt(uint8_t *, const uint8_t *, const size_t,
	const uint8_t *, const size_t, const uint64_t,
	const uint8_t[CHACHA20POLY1305_KEY_SIZE]);

void xchacha20poly1305_encrypt(uint8_t *, const uint8_t *, const size_t,
	const uint8_t *, const size_t,
	const uint8_t[XCHACHA20POLY1305_NONCE_SIZE],
	const uint8_t[CHACHA20POLY1305_KEY_SIZE]);

int xchacha20poly1305_decrypt(uint8_t *, const uint8_t *, const size_t,
	const uint8_t *, const size_t,
	const uint8_t[XCHACHA20POLY1305_NONCE_SIZE],
	const uint8_t[CHACHA20POLY1305_KEY_SIZE]);

#endif	/* _CHACHAPOLY_H_ */