/*
 * ProFTPD - mod_sftp cipher mgmt
 * Copyright (c) 2008-2023 TJ Saunders
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
 *
 * As a special exemption, TJ Saunders and other respective copyright holders
 * give permission to link this program with OpenSSL, and distribute the
 * resulting executable, without including the source code for OpenSSL in the
 * source distribution.
 */

#ifndef MOD_SFTP_CIPHER_H
#define MOD_SFTP_CIPHER_H

#include "mod_sftp.h"

int sftp_cipher_init(void);
int sftp_cipher_free(void);

/* Returns the cipher block size, or 8, whichever is larger. This value is
 * used when reading in the first bytes of a packet in order to determine
 * the packet length.  See RFC4253, Section 6, "Binary Packet Protocol".
 */
size_t sftp_cipher_get_read_block_size(void);
size_t sftp_cipher_get_write_block_size(void);
void sftp_cipher_set_read_block_size(size_t);
void sftp_cipher_set_write_block_size(size_t);

int sftp_cipher_is_read_chachapoly(void);

/* Returns the cipher authenticated data size, or zero. */
size_t sftp_cipher_get_read_auth_size(void);
size_t sftp_cipher_get_read_auth_size2(void);
size_t sftp_cipher_get_write_auth_size(void);
size_t sftp_cipher_get_write_auth_size2(void);

const char *sftp_cipher_get_read_algo(void);
int sftp_cipher_set_read_algo(const char *algo);
int sftp_cipher_set_read_key(pool *p, const EVP_MD *md, const unsigned char *k,
  uint32_t klen, const char *h, uint32_t hlen, int role);
int sftp_cipher_read_data(struct ssh2_packet *pkt, unsigned char *data,
  uint32_t data_len, unsigned char **buf, uint32_t *buflen);
int sftp_cipher_read_packet_len(struct ssh2_packet *pkt, unsigned char *data,
  uint32_t data_len, unsigned char **buf, uint32_t *buflen,
  uint32_t *packet_len);

const char *sftp_cipher_get_write_algo(void);
int sftp_cipher_set_write_algo(const char *algo);
int sftp_cipher_set_write_key(pool *p, const EVP_MD *md, const unsigned char *k,
  uint32_t klen, const char *h, uint32_t hlen, int role);
int sftp_cipher_write_data(struct ssh2_packet *pkt, unsigned char *buf,
  size_t *buflen);

#endif /* MOD_SFTP_CIPHER_H */
