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/* net_crypto.h
*
* Functions for the core network crypto.
*
* Copyright (C) 2013 Tox project All Rights Reserved.
*
* This file is part of Tox.
*
* Tox 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 3 of the License, or
* (at your option) any later version.
*
* Tox 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 Tox. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef NET_CRYPTO_H
#define NET_CRYPTO_H
#include "Lossless_UDP.h"
#define CRYPTO_PACKET_FRIEND_REQ 32 /* Friend request crypto packet ID. */
#define CRYPTO_PACKET_NAT_PING 254 /* NAT ping crypto packet ID. */
#define CRYPTO_HANDSHAKE_TIMEOUT CONNEXION_TIMEOUT
typedef struct {
uint8_t public_key[crypto_box_PUBLICKEYBYTES]; /* The real public key of the peer. */
uint8_t recv_nonce[crypto_box_NONCEBYTES]; /* Nonce of received packets. */
uint8_t sent_nonce[crypto_box_NONCEBYTES]; /* Nonce of sent packets. */
uint8_t sessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* Our public key for this session. */
uint8_t sessionsecret_key[crypto_box_SECRETKEYBYTES]; /* Our private key for this session. */
uint8_t peersessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* The public key of the peer. */
uint8_t shared_key[crypto_box_BEFORENMBYTES]; /* The precomputed shared key from encrypt_precompute. */
uint8_t status; /* 0 if no connection, 1 we have sent a handshake, 2 if connexion is not confirmed yet
* (we have received a handshake but no empty data packet), 3 if the connection is established.
* 4 if the connection is timed out.
*/
uint16_t number; /* Lossless_UDP connection number corresponding to this connection. */
uint64_t timeout;
} Crypto_Connection;
typedef int (*cryptopacket_handler_callback)(void *object, IP_Port ip_port, uint8_t *source_pubkey, uint8_t *data,
uint32_t len);
typedef struct {
cryptopacket_handler_callback function;
void *object;
} Cryptopacket_Handles;
typedef struct {
Lossless_UDP *lossless_udp;
Crypto_Connection *crypto_connections;
uint32_t crypto_connections_length; /* Length of connections array. */
/* Our public and secret keys. */
uint8_t self_public_key[crypto_box_PUBLICKEYBYTES];
uint8_t self_secret_key[crypto_box_SECRETKEYBYTES];
Cryptopacket_Handles cryptopackethandlers[256];
} Net_Crypto;
#include "DHT.h"
#define ENCRYPTION_PADDING (crypto_box_ZEROBYTES - crypto_box_BOXZEROBYTES)
/* return zero if the buffer contains only zeros. */
uint8_t crypto_iszero(uint8_t *buffer, uint32_t blen);
/* Encrypts plain of length length to encrypted of length + 16 using the
* public key(32 bytes) of the receiver and the secret key of the sender and a 24 byte nonce.
*
* return -1 if there was a problem.
* return length of encrypted data if everything was fine.
*/
int encrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted);
/* Decrypts encrypted of length length to plain of length length - 16 using the
* public key(32 bytes) of the sender, the secret key of the receiver and a 24 byte nonce.
*
* return -1 if there was a problem (decryption failed).
* return length of plain data if everything was fine.
*/
int decrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain);
/* Fast encrypt/decrypt operations. Use if this is not a one-time communication.
encrypt_precompute does the shared-key generation once so it does not have
to be preformed on every encrypt/decrypt. */
void encrypt_precompute(uint8_t *public_key, uint8_t *secret_key, uint8_t *enc_key);
/* Fast encrypt. Depends on enc_key from encrypt_precompute. */
int encrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted);
/* Fast decrypt. Depends on enc_ley from encrypt_precompute. */
int decrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain);
/* Fill the given nonce with random bytes. */
void random_nonce(uint8_t *nonce);
/*Gives a nonce guaranteed to be different from previous ones.*/
void new_nonce(uint8_t *nonce);
/* return 0 if there is no received data in the buffer.
* return -1 if the packet was discarded.
* return length of received data if successful.
*/
int read_cryptpacket(Net_Crypto *c, int crypt_connection_id, uint8_t *data);
/* returns the number of packet slots left in the sendbuffer.
* return 0 if failure.
*/
uint32_t crypto_num_free_sendqueue_slots(Net_Crypto *c, int crypt_connection_id);
/* return 0 if data could not be put in packet queue.
* return 1 if data was put into the queue.
*/
int write_cryptpacket(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint32_t length);
/* Create a request to peer.
* send_public_key and send_secret_key are the pub/secret keys of the sender.
* recv_public_key is public key of reciever.
* packet must be an array of MAX_DATA_SIZE big.
* Data represents the data we send with the request with length being the length of the data.
* request_id is the id of the request (32 = friend request, 254 = ping request).
*
* return -1 on failure.
* return the length of the created packet on success.
*/
int create_request(uint8_t *send_public_key, uint8_t *send_secret_key, uint8_t *packet, uint8_t *recv_public_key,
uint8_t *data, uint32_t length, uint8_t request_id);
/* puts the senders public key in the request in public_key, the data from the request
in data if a friend or ping request was sent to us and returns the length of the data.
packet is the request packet and length is its length
return -1 if not valid request. */
int handle_request(uint8_t *self_public_key, uint8_t *self_secret_key, uint8_t *public_key, uint8_t *data,
uint8_t *request_id, uint8_t *packet, uint16_t length);
/* Function to call when request beginning with byte is received. */
void cryptopacket_registerhandler(Net_Crypto *c, uint8_t byte, cryptopacket_handler_callback cb, void *object);
/* Start a secure connection with other peer who has public_key and ip_port.
*
* return -1 if failure.
* return crypt_connection_id of the initialized connection if everything went well.
*/
int crypto_connect(Net_Crypto *c, uint8_t *public_key, IP_Port ip_port);
/* Kill a crypto connection.
*
* return 0 if killed successfully.
* return 1 if there was a problem.
*/
int crypto_kill(Net_Crypto *c, int crypt_connection_id);
/* Handle an incoming connection.
*
* return -1 if no crypto inbound connection.
* return incoming connection id (Lossless_UDP one) if there is an incoming crypto connection.
*
* Put the public key of the peer in public_key, the secret_nonce from the handshake into secret_nonce
* and the session public key for the connection in session_key.
* to accept it see: accept_crypto_inbound(...).
* to refuse it just call kill_connection(...) on the connection id.
*/
int crypto_inbound(Net_Crypto *c, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key);
/* Accept an incoming connection using the parameters provided by crypto_inbound.
*
* return -1 if not successful.
* return crypt_connection_id if successful.
*/
int accept_crypto_inbound(Net_Crypto *c, int connection_id, uint8_t *public_key, uint8_t *secret_nonce,
uint8_t *session_key);
/* return 0 if no connection.
* return 1 we have sent a handshake
* return 2 if connexion is not confirmed yet (we have received a handshake but no empty data packet).
* return 3 if the connection is established.
* return 4 if the connection is timed out and waiting to be killed.
*/
int is_cryptoconnected(Net_Crypto *c, int crypt_connection_id);
/* Generate our public and private keys.
* Only call this function the first time the program starts.
*/
void new_keys(Net_Crypto *c);
/* Save the public and private keys to the keys array.
* Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES.
*/
void save_keys(Net_Crypto *c, uint8_t *keys);
/* Load the public and private keys from the keys array.
* Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES.
*/
void load_keys(Net_Crypto *c, uint8_t *keys);
/* Create new instance of Net_Crypto.
* Sets all the global connection variables to their default values.
*/
Net_Crypto *new_net_crypto(Networking_Core *net);
/* Main loop. */
void do_net_crypto(Net_Crypto *c);
void kill_net_crypto(Net_Crypto *c);
/* Initialize the cryptopacket handling. */
void init_cryptopackets(void *dht);
#endif
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