/* SPDX-License-Identifier: ISC
 *
 * Copyright (C) 2015-2021 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 * Copyright (C) 2019-2021 Matt Dunwoodie <ncon@noconroy.net>
 */

#ifndef __NOISE_H__
#define __NOISE_H__

#include "crypto.h"

#define NOISE_PUBLIC_KEY_LEN    CURVE25519_KEY_SIZE
#define NOISE_SYMMETRIC_KEY_LEN CHACHA20POLY1305_KEY_SIZE
#define NOISE_TIMESTAMP_LEN     (sizeof(uint64_t) + sizeof(uint32_t))
#define NOISE_AUTHTAG_LEN       CHACHA20POLY1305_AUTHTAG_SIZE
#define NOISE_HASH_LEN          BLAKE2S_HASH_SIZE

#define REJECT_AFTER_TIME       180
#define REKEY_TIMEOUT           5
#define KEEPALIVE_TIMEOUT       10

struct noise_local;
struct noise_remote;
struct noise_keypair;

/* Local configuration */
struct noise_local *
        noise_local_alloc(void *);
struct noise_local *
        noise_local_ref(struct noise_local *);
void    noise_local_put(struct noise_local *);
void    noise_local_free(struct noise_local *, void (*)(struct noise_local *));
void *  noise_local_arg(struct noise_local *);

void    noise_local_private(struct noise_local *,
            const uint8_t[NOISE_PUBLIC_KEY_LEN]);
int     noise_local_keys(struct noise_local *,
            uint8_t[NOISE_PUBLIC_KEY_LEN],
            uint8_t[NOISE_PUBLIC_KEY_LEN]);

/* Remote configuration */
struct noise_remote *
        noise_remote_alloc(struct noise_local *, void *,
            const uint8_t[NOISE_PUBLIC_KEY_LEN]);
int     noise_remote_enable(struct noise_remote *);
void    noise_remote_disable(struct noise_remote *);
struct noise_remote *
        noise_remote_lookup(struct noise_local *, const uint8_t[NOISE_PUBLIC_KEY_LEN]);
struct noise_remote *
        noise_remote_index(struct noise_local *, uint32_t);
struct noise_remote *
        noise_remote_ref(struct noise_remote *);
void    noise_remote_put(struct noise_remote *);
void    noise_remote_free(struct noise_remote *, void (*)(struct noise_remote *));
struct noise_local *
        noise_remote_local(struct noise_remote *);
void *  noise_remote_arg(struct noise_remote *);

void    noise_remote_set_psk(struct noise_remote *,
            const uint8_t[NOISE_SYMMETRIC_KEY_LEN]);
int     noise_remote_keys(struct noise_remote *,
            uint8_t[NOISE_PUBLIC_KEY_LEN],
            uint8_t[NOISE_SYMMETRIC_KEY_LEN]);
int     noise_remote_initiation_expired(struct noise_remote *);
void    noise_remote_handshake_clear(struct noise_remote *);
void    noise_remote_keypairs_clear(struct noise_remote *);

/* Keypair functions */
struct noise_keypair *
        noise_keypair_lookup(struct noise_local *, uint32_t);
struct noise_keypair *
        noise_keypair_current(struct noise_remote *);
struct noise_keypair *
        noise_keypair_ref(struct noise_keypair *);
int     noise_keypair_received_with(struct noise_keypair *);
void    noise_keypair_put(struct noise_keypair *);

struct noise_remote *
        noise_keypair_remote(struct noise_keypair *);

int     noise_keypair_nonce_next(struct noise_keypair *, uint64_t *);
int     noise_keypair_nonce_check(struct noise_keypair *, uint64_t);

int     noise_keep_key_fresh_send(struct noise_remote *);
int     noise_keep_key_fresh_recv(struct noise_remote *);
int     noise_keypair_encrypt(
            struct noise_keypair *,
            uint32_t *r_idx,
            uint64_t nonce,
            struct mbuf *);
int     noise_keypair_decrypt(
            struct noise_keypair *,
            uint64_t nonce,
            struct mbuf *);

/* Handshake functions */
int     noise_create_initiation(
            struct noise_remote *,
            uint32_t *s_idx,
            uint8_t ue[NOISE_PUBLIC_KEY_LEN],
            uint8_t es[NOISE_PUBLIC_KEY_LEN + NOISE_AUTHTAG_LEN],
            uint8_t ets[NOISE_TIMESTAMP_LEN + NOISE_AUTHTAG_LEN]);

int     noise_consume_initiation(
            struct noise_local *,
            struct noise_remote **,
            uint32_t s_idx,
            uint8_t ue[NOISE_PUBLIC_KEY_LEN],
            uint8_t es[NOISE_PUBLIC_KEY_LEN + NOISE_AUTHTAG_LEN],
            uint8_t ets[NOISE_TIMESTAMP_LEN + NOISE_AUTHTAG_LEN]);

int     noise_create_response(
            struct noise_remote *,
            uint32_t *s_idx,
            uint32_t *r_idx,
            uint8_t ue[NOISE_PUBLIC_KEY_LEN],
            uint8_t en[0 + NOISE_AUTHTAG_LEN]);

int     noise_consume_response(
            struct noise_local *,
            struct noise_remote **,
            uint32_t s_idx,
            uint32_t r_idx,
            uint8_t ue[NOISE_PUBLIC_KEY_LEN],
            uint8_t en[0 + NOISE_AUTHTAG_LEN]);

#ifdef SELFTESTS
bool    noise_counter_selftest(void);
#endif /* SELFTESTS */

#endif /* __NOISE_H__ */