/*
* An implementation of the DHT as seen in docs/updates/DHT.md
*/
/*
* Copyright © 2016-2017 The TokTok team.
* Copyright © 2013 Tox project.
*
* This file is part of Tox, the free peer to peer instant messenger.
*
* 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 .
*/
#ifndef DHT_H
#define DHT_H
#include "crypto_core.h"
#include "logger.h"
#include "network.h"
#include "ping_array.h"
#include
/* Maximum number of clients stored per friend. */
#define MAX_FRIEND_CLIENTS 8
#define LCLIENT_NODES (MAX_FRIEND_CLIENTS)
#define LCLIENT_LENGTH 128
/* A list of the clients mathematically closest to ours. */
#define LCLIENT_LIST (LCLIENT_LENGTH * LCLIENT_NODES)
#define MAX_CLOSE_TO_BOOTSTRAP_NODES 8
/* The max number of nodes to send with send nodes. */
#define MAX_SENT_NODES 4
/* Ping timeout in seconds */
#define PING_TIMEOUT 5
/* size of DHT ping arrays. */
#define DHT_PING_ARRAY_SIZE 512
/* Ping interval in seconds for each node in our lists. */
#define PING_INTERVAL 60
/* The number of seconds for a non responsive node to become bad. */
#define PINGS_MISSED_NODE_GOES_BAD 1
#define PING_ROUNDTRIP 2
#define BAD_NODE_TIMEOUT (PING_INTERVAL + PINGS_MISSED_NODE_GOES_BAD * (PING_INTERVAL + PING_ROUNDTRIP))
/* The number of "fake" friends to add (for optimization purposes and so our paths for the onion part are more random) */
#define DHT_FAKE_FRIEND_NUMBER 2
#define MAX_CRYPTO_REQUEST_SIZE 1024
#define CRYPTO_PACKET_FRIEND_REQ 32 /* Friend request crypto packet ID. */
#define CRYPTO_PACKET_HARDENING 48 /* Hardening crypto packet ID. */
#define CRYPTO_PACKET_DHTPK 156
#define CRYPTO_PACKET_NAT_PING 254 /* NAT ping crypto packet ID. */
/* 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 receiver.
* packet must be an array of MAX_CRYPTO_REQUEST_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(const uint8_t *send_public_key, const uint8_t *send_secret_key, uint8_t *packet,
const uint8_t *recv_public_key, const 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(const uint8_t *self_public_key, const uint8_t *self_secret_key, uint8_t *public_key, uint8_t *data,
uint8_t *request_id, const uint8_t *packet, uint16_t length);
typedef struct {
IP_Port ip_port;
uint64_t timestamp;
} IPPTs;
typedef struct {
/* Node routes request correctly (true (1) or false/didn't check (0)) */
uint8_t routes_requests_ok;
/* Time which we last checked this.*/
uint64_t routes_requests_timestamp;
uint8_t routes_requests_pingedid[CRYPTO_PUBLIC_KEY_SIZE];
/* Node sends correct send_node (true (1) or false/didn't check (0)) */
uint8_t send_nodes_ok;
/* Time which we last checked this.*/
uint64_t send_nodes_timestamp;
uint8_t send_nodes_pingedid[CRYPTO_PUBLIC_KEY_SIZE];
/* Node can be used to test other nodes (true (1) or false/didn't check (0)) */
uint8_t testing_requests;
/* Time which we last checked this.*/
uint64_t testing_timestamp;
uint8_t testing_pingedid[CRYPTO_PUBLIC_KEY_SIZE];
} Hardening;
typedef struct {
IP_Port ip_port;
uint64_t timestamp;
uint64_t last_pinged;
Hardening hardening;
/* Returned by this node. Either our friend or us. */
IP_Port ret_ip_port;
uint64_t ret_timestamp;
} IPPTsPng;
typedef struct {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
IPPTsPng assoc4;
IPPTsPng assoc6;
} Client_data;
/*----------------------------------------------------------------------------------*/
typedef struct {
/* 1 if currently hole punching, otherwise 0 */
uint8_t hole_punching;
uint32_t punching_index;
uint32_t tries;
uint32_t punching_index2;
uint64_t punching_timestamp;
uint64_t recvNATping_timestamp;
uint64_t NATping_id;
uint64_t NATping_timestamp;
} NAT;
#define DHT_FRIEND_MAX_LOCKS 32
typedef struct {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
IP_Port ip_port;
}
Node_format;
typedef struct {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
Client_data client_list[MAX_FRIEND_CLIENTS];
/* Time at which the last get_nodes request was sent. */
uint64_t lastgetnode;
/* number of times get_node packets were sent. */
uint32_t bootstrap_times;
/* Symetric NAT hole punching stuff. */
NAT nat;
uint16_t lock_count;
struct {
void (*ip_callback)(void *, int32_t, IP_Port);
void *data;
int32_t number;
} callbacks[DHT_FRIEND_MAX_LOCKS];
Node_format to_bootstrap[MAX_SENT_NODES];
unsigned int num_to_bootstrap;
} DHT_Friend;
/* Return packet size of packed node with ip_family on success.
* Return -1 on failure.
*/
int packed_node_size(uint8_t ip_family);
/* Pack number of nodes into data of maxlength length.
*
* return length of packed nodes on success.
* return -1 on failure.
*/
int pack_nodes(uint8_t *data, uint16_t length, const Node_format *nodes, uint16_t number);
/* Unpack data of length into nodes of size max_num_nodes.
* Put the length of the data processed in processed_data_len.
* tcp_enabled sets if TCP nodes are expected (true) or not (false).
*
* return number of unpacked nodes on success.
* return -1 on failure.
*/
int unpack_nodes(Node_format *nodes, uint16_t max_num_nodes, uint16_t *processed_data_len, const uint8_t *data,
uint16_t length, uint8_t tcp_enabled);
/*----------------------------------------------------------------------------------*/
/* struct to store some shared keys so we don't have to regenerate them for each request. */
#define MAX_KEYS_PER_SLOT 4
#define KEYS_TIMEOUT 600
typedef struct {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint8_t shared_key[CRYPTO_SHARED_KEY_SIZE];
uint32_t times_requested;
uint8_t stored; /* 0 if not, 1 if is */
uint64_t time_last_requested;
} Shared_Key;
typedef struct {
Shared_Key keys[256 * MAX_KEYS_PER_SLOT];
} Shared_Keys;
/*----------------------------------------------------------------------------------*/
typedef int (*cryptopacket_handler_callback)(void *object, IP_Port ip_port, const uint8_t *source_pubkey,
const uint8_t *data, uint16_t len, void *userdata);
typedef struct {
cryptopacket_handler_callback function;
void *object;
} Cryptopacket_Handles;
typedef struct {
Logger *log;
Networking_Core *net;
bool hole_punching_enabled;
Client_data close_clientlist[LCLIENT_LIST];
uint64_t close_lastgetnodes;
uint32_t close_bootstrap_times;
/* Note: this key should not be/is not used to transmit any sensitive materials */
uint8_t secret_symmetric_key[CRYPTO_SYMMETRIC_KEY_SIZE];
/* DHT keypair */
uint8_t self_public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint8_t self_secret_key[CRYPTO_SECRET_KEY_SIZE];
DHT_Friend *friends_list;
uint16_t num_friends;
Node_format *loaded_nodes_list;
uint32_t loaded_num_nodes;
unsigned int loaded_nodes_index;
Shared_Keys shared_keys_recv;
Shared_Keys shared_keys_sent;
struct PING *ping;
Ping_Array dht_ping_array;
Ping_Array dht_harden_ping_array;
uint64_t last_run;
Cryptopacket_Handles cryptopackethandlers[256];
Node_format to_bootstrap[MAX_CLOSE_TO_BOOTSTRAP_NODES];
unsigned int num_to_bootstrap;
} DHT;
/*----------------------------------------------------------------------------------*/
/* Shared key generations are costly, it is therefor smart to store commonly used
* ones so that they can re used later without being computed again.
*
* If shared key is already in shared_keys, copy it to shared_key.
* else generate it into shared_key and copy it to shared_keys
*/
void get_shared_key(Shared_Keys *shared_keys, uint8_t *shared_key, const uint8_t *secret_key,
const uint8_t *public_key);
/* Copy shared_key to encrypt/decrypt DHT packet from public_key into shared_key
* for packets that we receive.
*/
void DHT_get_shared_key_recv(DHT *dht, uint8_t *shared_key, const uint8_t *public_key);
/* Copy shared_key to encrypt/decrypt DHT packet from public_key into shared_key
* for packets that we send.
*/
void DHT_get_shared_key_sent(DHT *dht, uint8_t *shared_key, const uint8_t *public_key);
void DHT_getnodes(DHT *dht, const IP_Port *from_ipp, const uint8_t *from_id, const uint8_t *which_id);
/* Add a new friend to the friends list.
* public_key must be CRYPTO_PUBLIC_KEY_SIZE bytes long.
*
* ip_callback is the callback of a function that will be called when the ip address
* is found along with arguments data and number.
*
* lock_count will be set to a non zero number that must be passed to DHT_delfriend()
* to properly remove the callback.
*
* return 0 if success.
* return -1 if failure (friends list is full).
*/
int DHT_addfriend(DHT *dht, const uint8_t *public_key, void (*ip_callback)(void *data, int32_t number, IP_Port),
void *data, int32_t number, uint16_t *lock_count);
/* Delete a friend from the friends list.
* public_key must be CRYPTO_PUBLIC_KEY_SIZE bytes long.
*
* return 0 if success.
* return -1 if failure (public_key not in friends list).
*/
int DHT_delfriend(DHT *dht, const uint8_t *public_key, uint16_t lock_count);
/* Get ip of friend.
* public_key must be CRYPTO_PUBLIC_KEY_SIZE bytes long.
* ip must be 4 bytes long.
* port must be 2 bytes long.
*
* int DHT_getfriendip(DHT *dht, uint8_t *public_key, IP_Port *ip_port);
*
* return -1, -- if public_key does NOT refer to a friend
* return 0, -- if public_key refers to a friend and we failed to find the friend (yet)
* return 1, ip if public_key refers to a friend and we found him
*/
int DHT_getfriendip(const DHT *dht, const uint8_t *public_key, IP_Port *ip_port);
/* Compares pk1 and pk2 with pk.
*
* return 0 if both are same distance.
* return 1 if pk1 is closer.
* return 2 if pk2 is closer.
*/
int id_closest(const uint8_t *pk, const uint8_t *pk1, const uint8_t *pk2);
/* Add node to the node list making sure only the nodes closest to cmp_pk are in the list.
*/
bool add_to_list(Node_format *nodes_list, unsigned int length, const uint8_t *pk, IP_Port ip_port,
const uint8_t *cmp_pk);
/* Return 1 if node can be added to close list, 0 if it can't.
*/
bool node_addable_to_close_list(DHT *dht, const uint8_t *public_key, IP_Port ip_port);
/* Get the (maximum MAX_SENT_NODES) closest nodes to public_key we know
* and put them in nodes_list (must be MAX_SENT_NODES big).
*
* sa_family = family (IPv4 or IPv6) (0 if we don't care)?
* is_LAN = return some LAN ips (true or false)
* want_good = do we want tested nodes or not? (TODO(irungentoo))
*
* return the number of nodes returned.
*
*/
int get_close_nodes(const DHT *dht, const uint8_t *public_key, Node_format *nodes_list, Family sa_family,
uint8_t is_LAN, uint8_t want_good);
/* Put up to max_num nodes in nodes from the random friends.
*
* return the number of nodes.
*/
uint16_t randfriends_nodes(DHT *dht, Node_format *nodes, uint16_t max_num);
/* Put up to max_num nodes in nodes from the closelist.
*
* return the number of nodes.
*/
uint16_t closelist_nodes(DHT *dht, Node_format *nodes, uint16_t max_num);
/* Run this function at least a couple times per second (It's the main loop). */
void do_DHT(DHT *dht);
/*
* Use these two functions to bootstrap the client.
*/
/* Sends a "get nodes" request to the given node with ip, port and public_key
* to setup connections
*/
void DHT_bootstrap(DHT *dht, IP_Port ip_port, const uint8_t *public_key);
/* Resolves address into an IP address. If successful, sends a "get nodes"
* request to the given node with ip, port and public_key to setup connections
*
* address can be a hostname or an IP address (IPv4 or IPv6).
* if ipv6enabled is 0 (zero), the resolving sticks STRICTLY to IPv4 addresses
* if ipv6enabled is not 0 (zero), the resolving looks for IPv6 addresses first,
* then IPv4 addresses.
*
* returns 1 if the address could be converted into an IP address
* returns 0 otherwise
*/
int DHT_bootstrap_from_address(DHT *dht, const char *address, uint8_t ipv6enabled,
uint16_t port, const uint8_t *public_key);
/* Start sending packets after DHT loaded_friends_list and loaded_clients_list are set.
*
* returns 0 if successful
* returns -1 otherwise
*/
int DHT_connect_after_load(DHT *dht);
/* ROUTING FUNCTIONS */
/* Send the given packet to node with public_key.
*
* return -1 if failure.
*/
int route_packet(const DHT *dht, const uint8_t *public_key, const uint8_t *packet, uint16_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(const DHT *dht, const uint8_t *friend_id, const uint8_t *packet, uint16_t length);
/* Function to handle crypto packets.
*/
void cryptopacket_registerhandler(DHT *dht, uint8_t byte, cryptopacket_handler_callback cb, void *object);
/* SAVE/LOAD functions */
/* Get the size of the DHT (for saving). */
uint32_t DHT_size(const DHT *dht);
/* Save the DHT in data where data is an array of size DHT_size(). */
void DHT_save(DHT *dht, uint8_t *data);
/* Load the DHT from data of size size.
*
* return -1 if failure.
* return 0 if success.
*/
int DHT_load(DHT *dht, const uint8_t *data, uint32_t length);
/* Initialize DHT. */
DHT *new_DHT(Logger *log, Networking_Core *net, bool holepunching_enabled);
void kill_DHT(DHT *dht);
/* return 0 if we are not connected to the DHT.
* return 1 if we are.
*/
int DHT_isconnected(const DHT *dht);
/* return 0 if we are not connected or only connected to lan peers with the DHT.
* return 1 if we are.
*/
int DHT_non_lan_connected(const DHT *dht);
uint32_t addto_lists(DHT *dht, IP_Port ip_port, const uint8_t *public_key);
#endif