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/* DHT.h
*
* An implementation of the DHT as seen in http://wiki.tox.im/index.php/DHT
*
* 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 DHT_H
#define DHT_H
#include "net_crypto.h"
/* Size of the client_id in bytes. */
#define CLIENT_ID_SIZE crypto_box_PUBLICKEYBYTES
/* Maximum number of clients stored per friend. */
#define MAX_FRIEND_CLIENTS 8
/* A list of the clients mathematically closest to ours. */
#define LCLIENT_LIST 32
/* The list of ip ports along with the ping_id of what we sent them and a timestamp. */
#define LPING_ARRAY 256 // NOTE: Deprecated (doesn't do anything).
#define LSEND_NODES_ARRAY LPING_ARRAY/2
/* Maximum newly announced nodes to ping per TIME_TOPING seconds. */
#define MAX_TOPING 16
typedef struct {
uint8_t client_id[CLIENT_ID_SIZE];
IP_Port ip_port;
uint64_t timestamp;
uint64_t last_pinged;
/* Returned by this node. Either our friend or us. */
IP_Port ret_ip_port;
uint64_t ret_timestamp;
} Client_data;
/*----------------------------------------------------------------------------------*/
typedef struct {
uint8_t client_id[CLIENT_ID_SIZE];
Client_data client_list[MAX_FRIEND_CLIENTS];
/* Time at which the last get_nodes request was sent. */
uint64_t lastgetnode;
/* Symetric NAT hole punching stuff. */
/* 1 if currently hole punching, otherwise 0 */
uint8_t hole_punching;
uint32_t punching_index;
uint64_t punching_timestamp;
uint64_t recvNATping_timestamp;
uint64_t NATping_id;
uint64_t NATping_timestamp;
} DHT_Friend;
typedef struct {
uint8_t client_id[CLIENT_ID_SIZE];
IP_Port ip_port;
} Node_format;
typedef struct {
IP_Port ip_port;
uint64_t ping_id;
uint64_t timestamp;
} Pinged;
/*----------------------------------------------------------------------------------*/
typedef struct {
Net_Crypto *c;
Client_data close_clientlist[LCLIENT_LIST];
DHT_Friend *friends_list;
uint16_t num_friends;
Pinged send_nodes[LSEND_NODES_ARRAY];
Node_format toping[MAX_TOPING];
uint64_t last_toping;
uint64_t close_lastgetnodes;
void *ping;
} DHT;
/*----------------------------------------------------------------------------------*/
Client_data *DHT_get_close_list(DHT *dht);
/* Add a new friend to the friends list.
* client_id must be CLIENT_ID_SIZE bytes long.
*
* return 0 if success.
* return 1 if failure (friends list is full).
*/
int DHT_addfriend(DHT *dht, uint8_t *client_id);
/* Delete a friend from the friends list.
* client_id must be CLIENT_ID_SIZE bytes long.
*
* return 0 if success.
* return 1 if failure (client_id not in friends list).
*/
int DHT_delfriend(DHT *dht, uint8_t *client_id);
/* Get ip of friend.
* client_id must be CLIENT_ID_SIZE bytes long.
* ip must be 4 bytes long.
* port must be 2 bytes long.
*
* return ip if success.
* return ip of 0 if failure (This means the friend is either offline or we have not found him yet).
* return ip of 1 if friend is not in list.
*/
IP_Port DHT_getfriendip(DHT *dht, uint8_t *client_id);
/* Run this function at least a couple times per second (It's the main loop). */
void do_DHT(DHT *dht);
/* Use this function to bootstrap the client.
* Sends a get nodes request to the given node with ip port and public_key.
*/
void DHT_bootstrap(DHT *dht, IP_Port ip_port, uint8_t *public_key);
/* Add nodes to the toping list.
* All nodes in this list are pinged every TIME_TOPING seconds
* and are then removed from the list.
* If the list is full the nodes farthest from our client_id are replaced.
* The purpose of this list is to enable quick integration of new nodes into the
* network while preventing amplification attacks.
*
* return 0 if node was added.
* return -1 if node was not added.
*/
int add_toping(DHT *dht, uint8_t *client_id, IP_Port ip_port);
/* ROUTING FUNCTIONS */
/* Send the given packet to node with client_id.
*
* return -1 if failure.
*/
int route_packet(DHT *dht, uint8_t *client_id, uint8_t *packet, uint32_t length);
/* Send the following packet to everyone who tells us they are connected to friend_id.
*
* return number of nodes it sent the packet to.
*/
int route_tofriend(DHT *dht, uint8_t *friend_id, uint8_t *packet, uint32_t length);
/* NAT PUNCHING FUNCTIONS */
/* Puts all the different ips returned by the nodes for a friend_id into array ip_portlist.
* ip_portlist must be at least MAX_FRIEND_CLIENTS big.
*
* returns number of ips returned.
* returns -1 if no such friend.
*/
int friend_ips(DHT *dht, IP_Port *ip_portlist, uint8_t *friend_id);
/* SAVE/LOAD functions */
/* Get the size of the DHT (for saving). */
uint32_t DHT_size(DHT *dht);
/* Save the DHT in data where data is an array of size DHT_size(). */
void DHT_save(DHT *dht, uint8_t *data);
/* Initialize DHT. */
DHT *new_DHT(Net_Crypto *c);
void kill_DHT(DHT *dht);
/* Load the DHT from data of size size.
*
* return -1 if failure.
* return 0 if success.
*/
int DHT_load(DHT *dht, uint8_t *data, uint32_t size);
/* return 0 if we are not connected to the DHT.
* return 1 if we are.
*/
int DHT_isconnected(DHT *dht);
void addto_lists(DHT *dht, IP_Port ip_port, uint8_t *client_id);
#endif
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