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toxcore/core/DHT.c

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/* DHT.c
*
* 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/>.
*
*/
/*----------------------------------------------------------------------------------*/
#include "DHT.h"
/* 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
#define LSEND_NODES_ARRAY LPING_ARRAY/2
/* the number of seconds for a non responsive node to become bad. */
#define BAD_NODE_TIMEOUT 70
/* the max number of nodes to send with send nodes. */
#define MAX_SENT_NODES 8
/* ping timeout in seconds */
#define PING_TIMEOUT 5
/* The timeout after which a node is discarded completely. */
#define Kill_NODE_TIMEOUT 300
/* ping interval in seconds for each node in our lists. */
#define PING_INTERVAL 60
/* ping interval in seconds for each random sending of a get nodes request. */
#define GET_NODE_INTERVAL 10
#define MAX_PUNCHING_PORTS 32
/*Interval in seconds between punching attempts*/
#define PUNCH_INTERVAL 10
/*----------------------------------------------------------------------------------*/
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;
} 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;
/*----------------------------------------------------------------------------------*/
/* Our client id/public key */
uint8_t self_public_key[CLIENT_ID_SIZE];
uint8_t self_secret_key[crypto_box_SECRETKEYBYTES];
static Client_data close_clientlist[LCLIENT_LIST];
static Friend * friends_list;
static uint16_t num_friends;
static Pinged pings[LPING_ARRAY];
static Pinged send_nodes[LSEND_NODES_ARRAY];
/*----------------------------------------------------------------------------------*/
/* Compares client_id1 and client_id2 with client_id
* return 0 if both are same distance
* return 1 if client_id1 is closer
* return 2 if client_id2 is closer
*/
static int id_closest(uint8_t * id, uint8_t * id1, uint8_t * id2)
{
size_t i;
uint8_t distance1, distance2;
for(i = 0; i < CLIENT_ID_SIZE; ++i) {
distance1 = abs(id[i] ^ id1[i]);
distance2 = abs(id[i] ^ id2[i]);
if(distance1 < distance2)
return 1;
if(distance1 > distance2)
return 2;
}
return 0;
}
static int ipport_equal(IP_Port a, IP_Port b)
{
return (a.ip.i == b.ip.i) && (a.port == b.port);
}
static int id_equal(uint8_t* a, uint8_t* b)
{
return memcmp(a, b, CLIENT_ID_SIZE) == 0;
}
static int is_timeout(uint64_t time_now, uint64_t timestamp, uint64_t timeout)
{
return timestamp + timeout <= time_now;
}
/* check if client with client_id is already in list of length length.
* if it is then set its corresponding timestamp to current time.
* if the id is already in the list with a different ip_port, update it.
* return True(1) or False(0)
*
* TODO: maybe optimize this.
*/
static int client_in_list(Client_data * list, uint32_t length, uint8_t * client_id, IP_Port ip_port)
{
uint32_t i;
uint64_t temp_time = unix_time();
for(i = 0; i < length; ++i) {
/*If ip_port is assigned to a different client_id replace it*/
if(ipport_equal(list[i].ip_port, ip_port)) {
memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
}
if(id_equal(list[i].client_id, client_id)) {
/* Refresh the client timestamp. */
list[i].timestamp = temp_time;
list[i].ip_port.ip.i = ip_port.ip.i;
list[i].ip_port.port = ip_port.port;
return 1;
}
}
return 0;
}
/* check if client with client_id is already in node format list of length length.
* return True(1) or False(0)
*/
static int client_in_nodelist(Node_format * list, uint32_t length, uint8_t * client_id)
{
uint32_t i;
for(i = 0; i < length; ++i) {
if(id_equal(list[i].client_id, client_id))
return 1;
}
return 0;
}
/* Returns the friend number from the client_id, or -1 if a failure occurs
*/
static int friend_number(uint8_t * client_id)
{
uint32_t i;
for(i = 0; i < num_friends; ++i) {
if(id_equal(friends_list[i].client_id, client_id))
return i;
}
return -1;
}
/* Find MAX_SENT_NODES nodes closest to the client_id for the send nodes request:
* put them in the nodes_list and return how many were found.
*
* TODO: For the love of based Allah make this function cleaner and much more efficient.
*/
static int get_close_nodes(uint8_t * client_id, Node_format * nodes_list)
{
uint32_t i, j, k;
uint64_t temp_time = unix_time();
int num_nodes = 0, closest, tout, inlist;
for (i = 0; i < LCLIENT_LIST; ++i) {
tout = is_timeout(temp_time, close_clientlist[i].timestamp, BAD_NODE_TIMEOUT);
inlist = client_in_nodelist(nodes_list, MAX_SENT_NODES, close_clientlist[i].client_id);
/* if node isn't good or is already in list. */
if(tout || inlist)
continue;
if(num_nodes < MAX_SENT_NODES) {
memcpy( nodes_list[num_nodes].client_id,
close_clientlist[i].client_id,
CLIENT_ID_SIZE );
nodes_list[num_nodes].ip_port = close_clientlist[i].ip_port;
num_nodes++;
} else {
for(j = 0; j < MAX_SENT_NODES; ++j) {
closest = id_closest( client_id,
nodes_list[j].client_id,
close_clientlist[i].client_id );
if(closest == 2) {
memcpy( nodes_list[j].client_id,
close_clientlist[i].client_id,
CLIENT_ID_SIZE);
nodes_list[j].ip_port = close_clientlist[i].ip_port;
break;
}
}
}
}
for(i = 0; i < num_friends; ++i) {
for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
tout = is_timeout(temp_time, friends_list[i].client_list[j].timestamp, BAD_NODE_TIMEOUT);
inlist = client_in_nodelist( nodes_list,
MAX_SENT_NODES,
friends_list[i].client_list[j].client_id);
/* if node isn't good or is already in list. */
if(tout || inlist)
continue;
if(num_nodes < MAX_SENT_NODES) {
memcpy( nodes_list[num_nodes].client_id,
friends_list[i].client_list[j].client_id,
CLIENT_ID_SIZE);
nodes_list[num_nodes].ip_port = friends_list[i].client_list[j].ip_port;
num_nodes++;
} else {
for(k = 0; k < MAX_SENT_NODES; ++k) {
closest = id_closest( client_id,
nodes_list[k].client_id,
friends_list[i].client_list[j].client_id );
if(closest == 2) {
memcpy( nodes_list[k].client_id,
friends_list[i].client_list[j].client_id,
CLIENT_ID_SIZE );
nodes_list[k].ip_port = friends_list[i].client_list[j].ip_port;
break;
}
}
}
}
}
return num_nodes;
}
/* replace first bad (or empty) node with this one
* return 0 if successful
* return 1 if not (list contains no bad nodes)
*/
static int replace_bad( Client_data * list,
uint32_t length,
uint8_t * client_id,
IP_Port ip_port )
{
uint32_t i;
uint64_t temp_time = unix_time();
for(i = 0; i < length; ++i) {
/* if node is bad */
if(is_timeout(temp_time, list[i].timestamp, BAD_NODE_TIMEOUT)) {
memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
list[i].ip_port = ip_port;
list[i].timestamp = temp_time;
list[i].ret_ip_port.ip.i = 0;
list[i].ret_ip_port.port = 0;
list[i].ret_timestamp = 0;
return 0;
}
}
return 1;
}
/* replace the first good node that is further to the comp_client_id than that of the client_id in the list */
static int replace_good( Client_data * list,
uint32_t length,
uint8_t * client_id,
IP_Port ip_port,
uint8_t * comp_client_id )
{
uint32_t i;
uint64_t temp_time = unix_time();
for(i = 0; i < length; ++i)
if(id_closest(comp_client_id, list[i].client_id, client_id) == 2) {
memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
list[i].ip_port = ip_port;
list[i].timestamp = temp_time;
list[i].ret_ip_port.ip.i = 0;
list[i].ret_ip_port.port = 0;
list[i].ret_timestamp = 0;
return 0;
}
return 1;
}
/* Attempt to add client with ip_port and client_id to the friends client list
* and close_clientlist
*/
static void addto_lists(IP_Port ip_port, uint8_t * client_id)
{
uint32_t i;
/* NOTE: current behavior if there are two clients with the same id is
* to replace the first ip by the second.
*/
if (!client_in_list(close_clientlist, LCLIENT_LIST, client_id, ip_port)) {
if (replace_bad(close_clientlist, LCLIENT_LIST, client_id, ip_port)) {
/* if we can't replace bad nodes we try replacing good ones */
replace_good( close_clientlist,
LCLIENT_LIST,
client_id,
ip_port,
self_public_key );
}
}
for (i = 0; i < num_friends; ++i) {
if (!client_in_list( friends_list[i].client_list,
MAX_FRIEND_CLIENTS,
client_id,
ip_port )) {
if (replace_bad( friends_list[i].client_list,
MAX_FRIEND_CLIENTS,
client_id,
ip_port )) {
/* if we can't replace bad nodes we try replacing good ones. */
replace_good( friends_list[i].client_list,
MAX_FRIEND_CLIENTS,
client_id,
ip_port,
friends_list[i].client_id );
}
}
}
}
/* If client_id is a friend or us, update ret_ip_port
* nodeclient_id is the id of the node that sent us this info
*/
static void returnedip_ports(IP_Port ip_port, uint8_t * client_id, uint8_t * nodeclient_id)
{
uint32_t i, j;
uint64_t temp_time = unix_time();
if (id_equal(client_id, self_public_key)) {
for (i = 0; i < LCLIENT_LIST; ++i) {
if (id_equal(nodeclient_id, close_clientlist[i].client_id)) {
close_clientlist[i].ret_ip_port = ip_port;
close_clientlist[i].ret_timestamp = temp_time;
return;
}
}
} else {
for (i = 0; i < num_friends; ++i) {
if (id_equal(client_id, friends_list[i].client_id)) {
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
if (id_equal(nodeclient_id, friends_list[i].client_list[j].client_id)) {
friends_list[i].client_list[j].ret_ip_port = ip_port;
friends_list[i].client_list[j].ret_timestamp = temp_time;
return;
}
}
}
}
}
}
/* check if we are currently pinging an ip_port and/or a ping_id variables with
* values of zero will not be checked. If we are already, return 1 else return 0
*
* TODO: optimize this
*/
static int is_pinging(IP_Port ip_port, uint64_t ping_id)
{
uint32_t i;
uint8_t pinging;
uint64_t temp_time = unix_time();
for (i = 0; i < LPING_ARRAY; ++i ) {
if (!is_timeout(temp_time, pings[i].timestamp, PING_TIMEOUT)) {
pinging = 0;
if (ip_port.ip.i != 0 && ipport_equal(pings[i].ip_port, ip_port))
++pinging;
if (ping_id != 0 && pings[i].ping_id == ping_id)
++pinging;
if (pinging == ((ping_id != 0) + (ip_port.ip.i != 0)))
return 1;
}
}
return 0;
}
/* Same as last function but for get_node requests. */
static int is_gettingnodes(IP_Port ip_port, uint64_t ping_id)
{
uint32_t i;
uint8_t pinging;
uint64_t temp_time = unix_time();
for(i = 0; i < LSEND_NODES_ARRAY; ++i ) {
if(!is_timeout(temp_time, send_nodes[i].timestamp, PING_TIMEOUT)) {
pinging = 0;
if(ip_port.ip.i != 0 && ipport_equal(send_nodes[i].ip_port, ip_port))
++pinging;
if(ping_id != 0 && send_nodes[i].ping_id == ping_id)
++pinging;
if(pinging == (ping_id != 0) + (ip_port.ip.i != 0))
return 1;
}
}
return 0;
}
/* Add a new ping request to the list of ping requests
* returns the ping_id to put in the ping request
* returns 0 if problem.
*
* TODO: optimize this
*/
static uint64_t add_pinging(IP_Port ip_port)
{
uint32_t i, j;
uint64_t ping_id = ((uint64_t)random_int() << 32) + random_int();
uint64_t temp_time = unix_time();
for(i = 0; i < PING_TIMEOUT; ++i ) {
for(j = 0; j < LPING_ARRAY; ++j ) {
if(is_timeout(temp_time, pings[j].timestamp, PING_TIMEOUT - i)) {
pings[j].timestamp = temp_time;
pings[j].ip_port = ip_port;
pings[j].ping_id = ping_id;
return ping_id;
}
}
}
return 0;
}
/* Same but for get node requests */
static uint64_t add_gettingnodes(IP_Port ip_port)
{
uint32_t i, j;
uint64_t ping_id = ((uint64_t)random_int() << 32) + random_int();
uint64_t temp_time = unix_time();
for(i = 0; i < PING_TIMEOUT; ++i ) {
for(j = 0; j < LSEND_NODES_ARRAY; ++j ) {
if(is_timeout(temp_time, send_nodes[j].timestamp, PING_TIMEOUT - i)) {
send_nodes[j].timestamp = temp_time;
send_nodes[j].ip_port = ip_port;
send_nodes[j].ping_id = ping_id;
return ping_id;
}
}
}
return 0;
}
/* send a ping request, only works if none has been sent to that ip/port
* in the last 5 seconds.
*/
static int pingreq(IP_Port ip_port, uint8_t * public_key)
{
/* check if packet is gonna be sent to ourself */
if(id_equal(public_key, self_public_key) || is_pinging(ip_port, 0))
return 1;
uint64_t ping_id = add_pinging(ip_port);
if(ping_id == 0)
return 1;
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING];
uint8_t encrypt[sizeof(ping_id) + ENCRYPTION_PADDING];
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
int len = encrypt_data( public_key,
self_secret_key,
nonce,
(uint8_t *)&ping_id,
sizeof(ping_id),
encrypt );
if(len != sizeof(ping_id) + ENCRYPTION_PADDING)
return -1;
data[0] = 0;
memcpy(data + 1, self_public_key, CLIENT_ID_SIZE);
memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES);
memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len);
return sendpacket(ip_port, data, sizeof(data));
}
/* send a ping response */
static int pingres(IP_Port ip_port, uint8_t * public_key, uint64_t ping_id)
{
/* check if packet is gonna be sent to ourself */
if(id_equal(public_key, self_public_key))
return 1;
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING];
uint8_t encrypt[sizeof(ping_id) + ENCRYPTION_PADDING];
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
int len = encrypt_data( public_key,
self_secret_key, nonce,
(uint8_t *)&ping_id,
sizeof(ping_id),
encrypt );
if(len != sizeof(ping_id) + ENCRYPTION_PADDING)
return -1;
data[0] = 1;
memcpy(data + 1, self_public_key, CLIENT_ID_SIZE);
memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES);
memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len);
return sendpacket(ip_port, data, sizeof(data));
}
/* send a getnodes request */
static int getnodes(IP_Port ip_port, uint8_t * public_key, uint8_t * client_id)
{
/* check if packet is gonna be sent to ourself */
if(id_equal(public_key, self_public_key) || is_gettingnodes(ip_port, 0))
return 1;
uint64_t ping_id = add_gettingnodes(ip_port);
if(ping_id == 0)
return 1;
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING];
uint8_t plain[sizeof(ping_id) + CLIENT_ID_SIZE];
uint8_t encrypt[sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING];
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
memcpy(plain, &ping_id, sizeof(ping_id));
memcpy(plain + sizeof(ping_id), client_id, CLIENT_ID_SIZE);
int len = encrypt_data( public_key,
self_secret_key,
nonce,
plain,
sizeof(ping_id) + CLIENT_ID_SIZE,
encrypt );
if(len != sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING)
return -1;
data[0] = 2;
memcpy(data + 1, self_public_key, CLIENT_ID_SIZE);
memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES);
memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len);
return sendpacket(ip_port, data, sizeof(data));
}
/* send a send nodes response */
static int sendnodes(IP_Port ip_port, uint8_t * public_key, uint8_t * client_id, uint64_t ping_id)
{
/* check if packet is gonna be sent to ourself */
if(id_equal(public_key, self_public_key))
return 1;
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id)
+ sizeof(Node_format) * MAX_SENT_NODES + ENCRYPTION_PADDING];
Node_format nodes_list[MAX_SENT_NODES];
int num_nodes = get_close_nodes(client_id, nodes_list);
if(num_nodes == 0)
return 0;
uint8_t plain[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES];
uint8_t encrypt[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES + ENCRYPTION_PADDING];
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
memcpy(plain, &ping_id, sizeof(ping_id));
memcpy(plain + sizeof(ping_id), nodes_list, num_nodes * sizeof(Node_format));
int len = encrypt_data( public_key,
self_secret_key,
nonce,
plain,
sizeof(ping_id) + num_nodes * sizeof(Node_format),
encrypt );
if(len != sizeof(ping_id) + num_nodes * sizeof(Node_format) + ENCRYPTION_PADDING)
return -1;
data[0] = 3;
memcpy(data + 1, self_public_key, CLIENT_ID_SIZE);
memcpy(data + 1 + CLIENT_ID_SIZE, nonce, crypto_box_NONCEBYTES);
memcpy(data + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES, encrypt, len);
return sendpacket(ip_port, data, 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + len);
}
/* Packet handling functions, one to handle each types of packets we receive
* Returns 0 if handled correctly, 1 if packet is bad.
*/
static int handle_pingreq(uint8_t * packet, uint32_t length, IP_Port source)
{
uint64_t ping_id;
if(length != 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
/* check if packet is from ourself. */
if(id_equal(packet + 1, self_public_key))
return 1;
int len = decrypt_data( packet + 1,
self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
sizeof(ping_id) + ENCRYPTION_PADDING,
(uint8_t *)&ping_id );
if(len != sizeof(ping_id))
return 1;
pingres(source, packet + 1, ping_id);
pingreq(source, packet + 1); /* TODO: make this smarter? */
return 0;
}
static int handle_pingres(uint8_t * packet, uint32_t length, IP_Port source)
{
uint64_t ping_id;
if(length != 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
/* check if packet is from ourself. */
if(id_equal(packet + 1, self_public_key))
return 1;
int len = decrypt_data( packet + 1,
self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
sizeof(ping_id) + ENCRYPTION_PADDING,
(uint8_t *)&ping_id );
if(len != sizeof(ping_id))
return 1;
if(is_pinging(source, ping_id)) {
addto_lists(source, packet + 1);
return 0;
}
return 1;
}
static int handle_getnodes(uint8_t * packet, uint32_t length, IP_Port source)
{
uint64_t ping_id;
if (length != ( 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES
+ sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING ))
return 1;
/* check if packet is from ourself. */
if (id_equal(packet + 1, self_public_key))
return 1;
uint8_t plain[sizeof(ping_id) + CLIENT_ID_SIZE];
int len = decrypt_data( packet + 1,
self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
sizeof(ping_id) + CLIENT_ID_SIZE + ENCRYPTION_PADDING,
plain );
if (len != sizeof(ping_id) + CLIENT_ID_SIZE)
return 1;
memcpy(&ping_id, plain, sizeof(ping_id));
sendnodes(source, packet + 1, plain + sizeof(ping_id), ping_id);
pingreq(source, packet + 1); /* TODO: make this smarter? */
return 0;
}
static int handle_sendnodes(uint8_t * packet, uint32_t length, IP_Port source)
{
uint64_t ping_id;
uint32_t cid_size = 1 + CLIENT_ID_SIZE;
cid_size += crypto_box_NONCEBYTES + sizeof(ping_id) + ENCRYPTION_PADDING;
if (length > (cid_size + sizeof(Node_format) * MAX_SENT_NODES) ||
((length - cid_size) % sizeof(Node_format)) != 0 ||
(length < cid_size + sizeof(Node_format)))
return 1;
uint32_t num_nodes = (length - cid_size) / sizeof(Node_format);
uint8_t plain[sizeof(ping_id) + sizeof(Node_format) * MAX_SENT_NODES];
int len = decrypt_data(
packet + 1,
self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
sizeof(ping_id) + num_nodes * sizeof(Node_format) + ENCRYPTION_PADDING, plain );
if(len != sizeof(ping_id) + num_nodes * sizeof(Node_format))
return 1;
memcpy(&ping_id, plain, sizeof(ping_id));
if(!is_gettingnodes(source, ping_id))
return 1;
Node_format nodes_list[MAX_SENT_NODES];
memcpy(nodes_list, plain + sizeof(ping_id), num_nodes * sizeof(Node_format));
addto_lists(source, packet + 1);
uint32_t i;
for(i = 0; i < num_nodes; ++i) {
pingreq(nodes_list[i].ip_port, nodes_list[i].client_id);
returnedip_ports(nodes_list[i].ip_port, nodes_list[i].client_id, packet + 1);
}
return 0;
}
/*----------------------------------------------------------------------------------*/
/*------------------------END of packet handling functions--------------------------*/
int DHT_addfriend(uint8_t * client_id)
{
Friend * temp;
temp = realloc(friends_list, sizeof(Friend) * (num_friends + 1));
if (temp == NULL)
return 1;
friends_list = temp;
memset(&friends_list[num_friends], 0, sizeof(Friend));
memcpy(friends_list[num_friends].client_id, client_id, CLIENT_ID_SIZE);
friends_list[num_friends].NATping_id = ((uint64_t)random_int() << 32) + random_int();
++num_friends;
return 0;
}
int DHT_delfriend(uint8_t * client_id)
{
uint32_t i;
Friend * temp;
for (i = 0; i < num_friends; ++i) {
/* Equal */
if (id_equal(friends_list[i].client_id, client_id)) {
--num_friends;
if (num_friends != i) {
memcpy( friends_list[i].client_id,
friends_list[num_friends].client_id,
CLIENT_ID_SIZE );
}
temp = realloc(friends_list, sizeof(Friend) * (num_friends));
if (temp == NULL)
return 1;
friends_list = temp;
return 0;
}
}
return 1;
}
/* TODO: Optimize this. */
IP_Port DHT_getfriendip(uint8_t * client_id)
{
uint32_t i, j;
uint64_t temp_time = unix_time();
IP_Port empty = {{{0}}, 0};
for (i = 0; i < num_friends; ++i) {
/* Equal */
if (id_equal(friends_list[i].client_id, client_id)) {
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
if (id_equal(friends_list[i].client_list[j].client_id, client_id) && !is_timeout(temp_time, friends_list[i].client_list[j].timestamp, BAD_NODE_TIMEOUT))
return friends_list[i].client_list[j].ip_port;
}
return empty;
}
}
empty.ip.i = 1;
return empty;
}
/* Ping each client in the "friends" list every 60 seconds. Send a get nodes request
* every 20 seconds to a random good node for each "friend" in our "friends" list.
*/
static void doDHTFriends(void)
{
uint32_t i, j;
uint64_t temp_time = unix_time();
uint32_t rand_node;
uint32_t index[MAX_FRIEND_CLIENTS];
for (i = 0; i < num_friends; ++i) {
uint32_t num_nodes = 0;
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
/* if node is not dead. */
if (!is_timeout(temp_time, friends_list[i].client_list[j].timestamp, Kill_NODE_TIMEOUT)) {
if ((friends_list[i].client_list[j].last_pinged + PING_INTERVAL) <= temp_time) {
pingreq( friends_list[i].client_list[j].ip_port,
friends_list[i].client_list[j].client_id );
friends_list[i].client_list[j].last_pinged = temp_time;
}
/* if node is good. */
if (!is_timeout(temp_time, friends_list[i].client_list[j].timestamp, BAD_NODE_TIMEOUT)) {
index[num_nodes] = j;
++num_nodes;
}
}
}
if(friends_list[i].lastgetnode + GET_NODE_INTERVAL <= temp_time && num_nodes != 0) {
rand_node = rand() % num_nodes;
getnodes( friends_list[i].client_list[index[rand_node]].ip_port,
friends_list[i].client_list[index[rand_node]].client_id,
friends_list[i].client_id );
friends_list[i].lastgetnode = temp_time;
}
}
}
static uint64_t close_lastgetnodes;
/* Ping each client in the close nodes list every 60 seconds.
* Send a get nodes request every 20 seconds to a random good node in the list.
*/
static void doClose(void)
{
uint32_t i;
uint64_t temp_time = unix_time();
uint32_t num_nodes = 0;
uint32_t rand_node;
uint32_t index[LCLIENT_LIST];
for (i = 0; i < LCLIENT_LIST; ++i) {
/* if node is not dead. */
if (!is_timeout(temp_time, close_clientlist[i].timestamp, Kill_NODE_TIMEOUT)) {
if ((close_clientlist[i].last_pinged + PING_INTERVAL) <= temp_time) {
pingreq( close_clientlist[i].ip_port,
close_clientlist[i].client_id );
close_clientlist[i].last_pinged = temp_time;
}
/* if node is good. */
if (!is_timeout(temp_time, close_clientlist[i].timestamp, BAD_NODE_TIMEOUT)) {
index[num_nodes] = i;
++num_nodes;
}
}
}
if (close_lastgetnodes + GET_NODE_INTERVAL <= temp_time && num_nodes != 0) {
rand_node = rand() % num_nodes;
getnodes( close_clientlist[index[rand_node]].ip_port,
close_clientlist[index[rand_node]].client_id,
self_public_key );
close_lastgetnodes = temp_time;
}
}
void DHT_bootstrap(IP_Port ip_port, uint8_t * public_key)
{
getnodes(ip_port, public_key, self_public_key);
}
/* send the given packet to node with client_id
* returns -1 if failure
*/
int route_packet(uint8_t * client_id, uint8_t * packet, uint32_t length)
{
uint32_t i;
for (i = 0; i < LCLIENT_LIST; ++i) {
if (id_equal(client_id, close_clientlist[i].client_id))
return sendpacket(close_clientlist[i].ip_port, packet, length);
}
return -1;
}
/* Puts all the different ips returned by the nodes for a friend_num into array ip_portlist
* ip_portlist must be at least MAX_FRIEND_CLIENTS big
* returns the number of ips returned
* return 0 if we are connected to friend or if no ips were found.
* returns -1 if no such friend
*/
static int friend_iplist(IP_Port * ip_portlist, uint16_t friend_num)
{
int num_ips = 0;
uint32_t i;
uint64_t temp_time = unix_time();
if (friend_num >= num_friends)
return -1;
Friend * friend = &friends_list[friend_num];
Client_data * client;
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
client = &friend->client_list[i];
/*If ip is not zero and node is good */
if (client->ret_ip_port.ip.i != 0 && !is_timeout(temp_time, client->ret_timestamp, BAD_NODE_TIMEOUT)) {
if (id_equal(client->client_id, friend->client_id))
return 0;
ip_portlist[num_ips] = client->ret_ip_port;
++num_ips;
}
}
return num_ips;
}
/* Send the following packet to everyone who tells us they are connected to friend_id
* returns the number of nodes it sent the packet to
*/
int route_tofriend(uint8_t * friend_id, uint8_t * packet, uint32_t length)
{
int num = friend_number(friend_id);
if (num == -1)
return 0;
uint32_t i, sent = 0;
uint64_t temp_time = unix_time();
Friend * friend = &friends_list[num];
Client_data * client;
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
client = &friend->client_list[i];
/*If ip is not zero and node is good */
if (client->ret_ip_port.ip.i != 0 && !is_timeout(temp_time, client->ret_timestamp, BAD_NODE_TIMEOUT)) {
if (sendpacket(client->ip_port, packet, length) == length)
++sent;
}
}
return sent;
}
/* Send the following packet to one random person who tells us they are connected to friend_id
* returns the number of nodes it sent the packet to
*/
static int routeone_tofriend(uint8_t * friend_id, uint8_t * packet, uint32_t length)
{
int num = friend_number(friend_id);
if (num == -1)
return 0;
Friend * friend = &friends_list[num];
Client_data * client;
IP_Port ip_list[MAX_FRIEND_CLIENTS];
int n = 0;
uint32_t i;
uint64_t temp_time = unix_time();
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
client = &friend->client_list[i];
/*If ip is not zero and node is good */
if(client->ret_ip_port.ip.i != 0 && !is_timeout(temp_time, client->ret_timestamp, BAD_NODE_TIMEOUT)) {
ip_list[n] = client->ip_port;
++n;
}
}
if (n < 1)
return 0;
if (sendpacket(ip_list[rand() % n], packet, length) == length)
return 1;
return 0;
}
/* 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 the number of ips returned
* return 0 if we are connected to friend or if no ips were found.
* returns -1 if no such friend
*/
int friend_ips(IP_Port * ip_portlist, uint8_t * friend_id)
{
uint32_t i;
for (i = 0; i < num_friends; ++i) {
/* Equal */
if (id_equal(friends_list[i].client_id, friend_id))
return friend_iplist(ip_portlist, i);
}
return -1;
}
/*----------------------------------------------------------------------------------*/
/*---------------------BEGINNING OF NAT PUNCHING FUNCTIONS--------------------------*/
static int send_NATping(uint8_t * public_key, uint64_t ping_id, uint8_t type)
{
uint8_t data[sizeof(uint64_t) + 1];
uint8_t packet[MAX_DATA_SIZE];
int num = 0;
data[0] = type;
memcpy(data + 1, &ping_id, sizeof(uint64_t));
/* 254 is NAT ping request packet id */
int len = create_request(packet, public_key, data, sizeof(uint64_t) + 1, 254);
if (len == -1)
return -1;
if (type == 0) /*If packet is request use many people to route it*/
num = route_tofriend(public_key, packet, len);
else if (type == 1) /*If packet is response use only one person to route it*/
num = routeone_tofriend(public_key, packet, len);
if (num == 0)
return -1;
return num;
}
/* Handle a recieved ping request for */
static int handle_NATping(uint8_t * packet, uint32_t length, IP_Port source)
{
if (length < crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + ENCRYPTION_PADDING
|| length > MAX_DATA_SIZE + ENCRYPTION_PADDING)
return 1;
/* check if request is for us. */
if (id_equal(packet + 1, self_public_key)) {
uint8_t public_key[crypto_box_PUBLICKEYBYTES];
uint8_t data[MAX_DATA_SIZE];
int len = handle_request(public_key, data, packet, length);
if (len != sizeof(uint64_t) + 1)
return 1;
uint64_t ping_id;
memcpy(&ping_id, data + 1, sizeof(uint64_t));
int friendnumber = friend_number(public_key);
if (friendnumber == -1)
return 1;
Friend * friend = &friends_list[friendnumber];
if (data[0] == 0) {
/* 1 is reply */
send_NATping(public_key, ping_id, 1);
friend->recvNATping_timestamp = unix_time();
return 0;
} else if (data[0] == 1) {
if (friend->NATping_id == ping_id) {
friend->NATping_id = ((uint64_t)random_int() << 32) + random_int();
friend->hole_punching = 1;
return 0;
}
}
return 1;
}
/* if request is not for us, try routing it. */
route_packet(packet + 1, packet, length);
return 0;
}
/* Get the most common ip in the ip_portlist
* Only return ip if it appears in list min_num or more
* len must not be bigger than MAX_FRIEND_CLIENTS
* return ip of 0 if failure
*/
static IP NAT_commonip(IP_Port * ip_portlist, uint16_t len, uint16_t min_num)
{
IP zero = {{0}};
if(len > MAX_FRIEND_CLIENTS)
return zero;
uint32_t i, j;
uint16_t numbers[MAX_FRIEND_CLIENTS] = {0};
for(i = 0; i < len; ++i) {
for(j = 0; j < len; ++j) {
if(ip_portlist[i].ip.i == ip_portlist[j].ip.i)
++numbers[i];
}
if(numbers[i] >= min_num)
return ip_portlist[i].ip;
}
return zero;
}
/* Return all the ports for one ip in a list
* portlist must be at least len long
* where len is the length of ip_portlist
* returns the number of ports and puts the list of ports in portlist
*/
static uint16_t NAT_getports(uint16_t * portlist, IP_Port * ip_portlist, uint16_t len, IP ip)
{
uint32_t i;
uint16_t num = 0;
for(i = 0; i < len; ++i) {
if(ip_portlist[i].ip.i == ip.i) {
portlist[num] = ntohs(ip_portlist[i].port);
++num;
}
}
return num;
}
static void punch_holes(IP ip, uint16_t * port_list, uint16_t numports, uint16_t friend_num)
{
if(numports > MAX_FRIEND_CLIENTS || numports == 0)
return;
uint32_t i;
uint32_t top = friends_list[friend_num].punching_index + MAX_PUNCHING_PORTS;
for(i = friends_list[friend_num].punching_index; i != top; i++) {
/*TODO: improve port guessing algorithm*/
uint16_t port = port_list[(i/2) % numports] + (i/(2*numports))*((i % 2) ? -1 : 1);
IP_Port pinging = {ip, htons(port)};
pingreq(pinging, friends_list[friend_num].client_id);
}
friends_list[friend_num].punching_index = i;
}
static void doNAT(void)
{
uint32_t i;
uint64_t temp_time = unix_time();
for (i = 0; i < num_friends; ++i) {
IP_Port ip_list[MAX_FRIEND_CLIENTS];
int num = friend_iplist(ip_list, i);
/*If already connected or friend is not online don't try to hole punch*/
if (num < MAX_FRIEND_CLIENTS/2)
continue;
if (friends_list[i].NATping_timestamp + PUNCH_INTERVAL < temp_time) {
send_NATping(friends_list[i].client_id, friends_list[i].NATping_id, 0); /*0 is request*/
friends_list[i].NATping_timestamp = temp_time;
}
if (friends_list[i].hole_punching == 1 &&
friends_list[i].punching_timestamp + PUNCH_INTERVAL < temp_time &&
friends_list[i].recvNATping_timestamp + PUNCH_INTERVAL*2 >= temp_time) {
IP ip = NAT_commonip(ip_list, num, MAX_FRIEND_CLIENTS/2);
if (ip.i == 0)
continue;
uint16_t port_list[MAX_FRIEND_CLIENTS];
uint16_t numports = NAT_getports(port_list, ip_list, num, ip);
punch_holes(ip, port_list, numports, i);
friends_list[i].punching_timestamp = temp_time;
friends_list[i].hole_punching = 0;
}
}
}
/*----------------------------------------------------------------------------------*/
/*-----------------------END OF NAT PUNCHING FUNCTIONS------------------------------*/
int DHT_handlepacket(uint8_t * packet, uint32_t length, IP_Port source)
{
switch (packet[0]) {
case 0:
return handle_pingreq(packet, length, source);
case 1:
return handle_pingres(packet, length, source);
case 2:
return handle_getnodes(packet, length, source);
case 3:
return handle_sendnodes(packet, length, source);
case 254:
return handle_NATping(packet, length, source);
default:
return 1;
}
return 0;
}
void doDHT(void)
{
doClose();
doDHTFriends();
doNAT();
}
/* get the size of the DHT (for saving) */
uint32_t DHT_size(void)
{
return sizeof(close_clientlist) + sizeof(Friend) * num_friends;
}
/* save the DHT in data where data is an array of size DHT_size() */
void DHT_save(uint8_t * data)
{
memcpy(data, close_clientlist, sizeof(close_clientlist));
memcpy(data + sizeof(close_clientlist), friends_list, sizeof(Friend) * num_friends);
}
/* load the DHT from data of size size;
* return -1 if failure
* return 0 if success
*/
int DHT_load(uint8_t * data, uint32_t size)
{
if(size < sizeof(close_clientlist))
return -1;
if((size - sizeof(close_clientlist)) % sizeof(Friend) != 0)
return -1;
uint32_t i, j;
uint16_t temp;
/* uint64_t temp_time = unix_time(); */
Client_data * client;
temp = (size - sizeof(close_clientlist))/sizeof(Friend);
if(temp != 0) {
Friend * tempfriends_list = (Friend *)(data + sizeof(close_clientlist));
for(i = 0; i < temp; ++i) {
DHT_addfriend(tempfriends_list[i].client_id);
for(j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
client = &tempfriends_list[i].client_list[j];
if(client->timestamp != 0)
getnodes(client->ip_port, client->client_id, tempfriends_list[i].client_id);
}
}
}
Client_data * tempclose_clientlist = (Client_data *)data;
for(i = 0; i < LCLIENT_LIST; ++i) {
if(tempclose_clientlist[i].timestamp != 0)
DHT_bootstrap( tempclose_clientlist[i].ip_port,
tempclose_clientlist[i].client_id );
}
return 0;
}
/* returns 0 if we are not connected to the DHT
* returns 1 if we are
*/
int DHT_isconnected(void)
{
uint32_t i;
uint64_t temp_time = unix_time();
for(i = 0; i < LCLIENT_LIST; ++i) {
if(!is_timeout(temp_time, close_clientlist[i].timestamp, BAD_NODE_TIMEOUT))
return 1;
}
return 0;
}
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