/* 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 .
*
*/
/*----------------------------------------------------------------------------------*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "DHT.h"
#include "network.h"
#include "ping.h"
#include "misc_tools.h"
#include "util.h"
#include "LAN_discovery.h"
/* 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 3
/* 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 5
#define MAX_PUNCHING_PORTS 128
/* Interval in seconds between punching attempts*/
#define PUNCH_INTERVAL 10
#define NAT_PING_REQUEST 0
#define NAT_PING_RESPONSE 1
/* Used in the comparison function for sorting lists of Client_data. */
typedef struct {
Client_data c1;
Client_data c2;
} ClientPair;
/* Create the declaration for a quick sort for ClientPair structures. */
declare_quick_sort(ClientPair);
/* Create the quicksort function. See misc_tools.h for the definition. */
make_quick_sort(ClientPair);
Client_data *DHT_get_close_list(DHT *dht)
{
return dht->close_clientlist;
}
/* 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.
*/
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(((int8_t *)id)[i] ^ ((int8_t *)id1)[i]);
distance2 = abs(((int8_t *)id)[i] ^ ((int8_t *)id2)[i]);
if (distance1 < distance2)
return 1;
if (distance1 > distance2)
return 2;
}
return 0;
}
/* Turns the result of id_closest into something quick_sort can use.
* Assumes p1->c1 == p2->c1.
*/
static int client_id_cmp(ClientPair p1, ClientPair p2)
{
int c = id_closest(p1.c1.client_id, p1.c2.client_id, p2.c2.client_id);
if (c == 2)
return -1;
return c;
}
static int client_in_list(Client_data *list, uint32_t length, uint8_t *client_id)
{
uint32_t i;
for (i = 0; i < length; i++)
/* Dead nodes are considered dead (not in the list)*/
if (!is_timeout(list[i].assoc4.timestamp, KILL_NODE_TIMEOUT) ||
!is_timeout(list[i].assoc6.timestamp, KILL_NODE_TIMEOUT))
if (id_equal(list[i].client_id, client_id))
return 1;
return 0;
}
/* 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.
* TODO: Maybe optimize this.
*
* return True(1) or False(0)
*/
static int client_or_ip_port_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();
/* if client_id is in list, find it and maybe overwrite ip_port */
for (i = 0; i < length; ++i)
if (id_equal(list[i].client_id, client_id)) {
/* Refresh the client timestamp. */
if (ip_port.ip.family == AF_INET) {
#ifdef LOGGING
if (!ipport_equal(&list[i].assoc4.ip_port, &ip_port)) {
size_t x;
x = sprintf(logbuffer, "coipil[%u]: switching ipv4 from %s:%u ", i,
ip_ntoa(&list[i].assoc4.ip_port.ip), ntohs(list[i].assoc4.ip_port.port));
sprintf(logbuffer + x, "to %s:%u\n",
ip_ntoa(&ip_port.ip), ntohs(ip_port.port));
loglog(logbuffer);
}
#endif
if (LAN_ip(list[i].assoc4.ip_port.ip) != 0 && LAN_ip(ip_port.ip) == 0)
return 1;
list[i].assoc4.ip_port = ip_port;
list[i].assoc4.timestamp = temp_time;
} else if (ip_port.ip.family == AF_INET6) {
#ifdef LOGGING
if (!ipport_equal(&list[i].assoc6.ip_port, &ip_port)) {
size_t x;
x = sprintf(logbuffer, "coipil[%u]: switching ipv6 from %s:%u ", i,
ip_ntoa(&list[i].assoc6.ip_port.ip), ntohs(list[i].assoc6.ip_port.port));
sprintf(logbuffer + x, "to %s:%u\n",
ip_ntoa(&ip_port.ip), ntohs(ip_port.port));
loglog(logbuffer);
}
#endif
if (LAN_ip(list[i].assoc6.ip_port.ip) != 0 && LAN_ip(ip_port.ip) == 0)
return 1;
list[i].assoc6.ip_port = ip_port;
list[i].assoc6.timestamp = temp_time;
}
return 1;
}
/* client_id not in list yet: see if we can find an identical ip_port, in
* that case we kill the old client_id by overwriting it with the new one
* TODO: maybe we SHOULDN'T do that if that client_id is in a friend_list
* and the one who is the actual friend's client_id/address set? */
for (i = 0; i < length; ++i) {
/* MAYBE: check the other address, if valid, don't nuke? */
if ((ip_port.ip.family == AF_INET) && ipport_equal(&list[i].assoc4.ip_port, &ip_port)) {
/* Initialize client timestamp. */
list[i].assoc4.timestamp = temp_time;
memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
#ifdef LOGGING
sprintf(logbuffer, "coipil[%u]: switching client_id (ipv4) \n", i);
loglog(logbuffer);
#endif
/* kill the other address, if it was set */
memset(&list[i].assoc6, 0, sizeof(list[i].assoc6));
return 1;
} else if ((ip_port.ip.family == AF_INET6) && ipport_equal(&list[i].assoc6.ip_port, &ip_port)) {
/* Initialize client timestamp. */
list[i].assoc6.timestamp = temp_time;
memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
#ifdef LOGGING
sprintf(logbuffer, "coipil[%u]: switching client_id (ipv6) \n", i);
loglog(logbuffer);
#endif
/* kill the other address, if it was set */
memset(&list[i].assoc4, 0, sizeof(list[i].assoc4));
return 1;
}
}
return 0;
}
/* Check if client with client_id is already in node format list of length length.
*
* return 1 if true.
* return 2 if false.
*/
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;
}
/* return friend number from the client_id.
* return -1 if a failure occurs.
*/
static int friend_number(DHT *dht, uint8_t *client_id)
{
uint32_t i;
for (i = 0; i < dht->num_friends; ++i) {
if (id_equal(dht->friends_list[i].client_id, client_id))
return i;
}
return -1;
}
/*
* helper for get_close_nodes(). argument list is a monster :D
*/
static void get_close_nodes_inner(DHT *dht, uint8_t *client_id, Node_format *nodes_list,
sa_family_t sa_family, Client_data *client_list, uint32_t client_list_length,
int *num_nodes_ptr, uint8_t is_LAN)
{
if ((sa_family != AF_INET) && (sa_family != AF_INET6))
return;
int num_nodes = *num_nodes_ptr;
int ipv46x, j, closest;
uint32_t i;
for (i = 0; i < client_list_length; i++) {
Client_data *client = &client_list[i];
/* node already in list? */
if (client_in_nodelist(nodes_list, MAX_SENT_NODES, client->client_id))
continue;
IPPTsPng *ipptp = NULL;
if (sa_family == AF_INET)
ipptp = &client->assoc4;
else
ipptp = &client->assoc6;
/* node not in a good condition? */
if (is_timeout(ipptp->timestamp, BAD_NODE_TIMEOUT))
continue;
IP *client_ip = &ipptp->ip_port.ip;
/*
* Careful: AF_INET isn't seen as AF_INET on dual-stack sockets for
* our connections, instead we have to look if it is an embedded
* IPv4-in-IPv6 here and convert it down in sendnodes().
*/
sa_family_t ip_treat_as_family = client_ip->family;
if ((dht->c->lossless_udp->net->family == AF_INET6) &&
(client_ip->family == AF_INET6)) {
/* socket is AF_INET6, address claims AF_INET6:
* check for embedded IPv4-in-IPv6 (shouldn't happen anymore,
* all storing functions should already convert down to IPv4) */
if (IN6_IS_ADDR_V4MAPPED(&client_ip->ip6.in6_addr))
ip_treat_as_family = AF_INET;
}
ipv46x = !(sa_family == ip_treat_as_family);
/* node address of the wrong family? */
if (ipv46x)
continue;
/* don't send LAN ips to non LAN peers */
if (LAN_ip(ipptp->ip_port.ip) == 0 && !is_LAN)
continue;
if (num_nodes < MAX_SENT_NODES) {
memcpy(nodes_list[num_nodes].client_id,
client->client_id,
CLIENT_ID_SIZE );
nodes_list[num_nodes].ip_port = ipptp->ip_port;
num_nodes++;
} else {
/* see if node_list contains a client_id that's "further away"
* compared to the one we're looking at at the moment, if there
* is, replace it
*/
for (j = 0; j < MAX_SENT_NODES; ++j) {
closest = id_closest( client_id,
nodes_list[j].client_id,
client->client_id );
/* second client_id is closer than current: change to it */
if (closest == 2) {
memcpy( nodes_list[j].client_id,
client->client_id,
CLIENT_ID_SIZE);
nodes_list[j].ip_port = ipptp->ip_port;
break;
}
}
}
}
*num_nodes_ptr = num_nodes;
}
/* 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 make
* this function cleaner and much more efficient.
*/
static int get_close_nodes(DHT *dht, uint8_t *client_id, Node_format *nodes_list, sa_family_t sa_family, uint8_t is_LAN)
{
int num_nodes = 0, i;
get_close_nodes_inner(dht, client_id, nodes_list, sa_family,
dht->close_clientlist, LCLIENT_LIST, &num_nodes, is_LAN);
for (i = 0; i < dht->num_friends; ++i)
get_close_nodes_inner(dht, client_id, nodes_list, sa_family,
dht->friends_list[i].client_list, MAX_FRIEND_CLIENTS,
&num_nodes, is_LAN);
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 )
{
if ((ip_port.ip.family != AF_INET) && (ip_port.ip.family != AF_INET6))
return 1;
uint32_t i;
for (i = 0; i < length; ++i) {
/* If node is bad */
Client_data *client = &list[i];
IPPTsPng *ipptp = NULL;
if (ip_port.ip.family == AF_INET)
ipptp = &client->assoc4;
else
ipptp = &client->assoc6;
if (is_timeout(ipptp->timestamp, BAD_NODE_TIMEOUT)) {
memcpy(client->client_id, client_id, CLIENT_ID_SIZE);
ipptp->ip_port = ip_port;
ipptp->timestamp = unix_time();
ip_reset(&ipptp->ret_ip_port.ip);
ipptp->ret_ip_port.port = 0;
ipptp->ret_timestamp = 0;
return 0;
}
}
return 1;
}
/* Sort the list. It will be sorted from furthest to closest.
* Turns list into data that quick sort can use and reverts it back.
*/
static void sort_list(Client_data *list, uint32_t length, uint8_t *comp_client_id)
{
Client_data cd;
ClientPair pairs[length];
uint32_t i;
memcpy(cd.client_id, comp_client_id, CLIENT_ID_SIZE);
for (i = 0; i < length; ++i) {
pairs[i].c1 = cd;
pairs[i].c2 = list[i];
}
ClientPair_quick_sort(pairs, length, client_id_cmp);
for (i = 0; i < length; ++i)
list[i] = pairs[i].c2;
}
/* 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 )
{
if ((ip_port.ip.family != AF_INET) && (ip_port.ip.family != AF_INET6))
return 1;
sort_list(list, length, comp_client_id);
int8_t replace = -1;
/* Because the list is sorted, we can simply check the client_id at the
* border, either it is closer, then every other one is as well, or it is
* further, then it gets pushed out in favor of the new address, which
* will with the next sort() move to its "rightful" position
*
* CAVEAT: weirdly enough, the list is sorted DESCENDING in distance
* so the furthest element is the first, NOT the last (at least that's
* what the comment above sort_list() claims)
*/
if (id_closest(comp_client_id, list[0].client_id, client_id) == 2)
replace = 0;
if (replace != -1) {
#ifdef DEBUG
assert(replace >= 0 && replace < length);
#endif
Client_data *client = &list[replace];
IPPTsPng *ipptp = NULL;
if (ip_port.ip.family == AF_INET)
ipptp = &client->assoc4;
else
ipptp = &client->assoc6;
memcpy(client->client_id, client_id, CLIENT_ID_SIZE);
ipptp->ip_port = ip_port;
ipptp->timestamp = unix_time();
ip_reset(&ipptp->ret_ip_port.ip);
ipptp->ret_ip_port.port = 0;
ipptp->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.
*/
void addto_lists(DHT *dht, IP_Port ip_port, uint8_t *client_id)
{
uint32_t i;
/* convert IPv4-in-IPv6 to IPv4 */
if ((ip_port.ip.family == AF_INET6) && IN6_IS_ADDR_V4MAPPED(&ip_port.ip.ip6.in6_addr)) {
ip_port.ip.family = AF_INET;
ip_port.ip.ip4.uint32 = ip_port.ip.ip6.uint32[3];
}
/* NOTE: Current behavior if there are two clients with the same id is
* to replace the first ip by the second.
*/
if (!client_or_ip_port_in_list(dht->close_clientlist, LCLIENT_LIST, client_id, ip_port)) {
if (replace_bad(dht->close_clientlist, LCLIENT_LIST, client_id, ip_port)) {
/* If we can't replace bad nodes we try replacing good ones. */
replace_good(dht->close_clientlist, LCLIENT_LIST, client_id, ip_port,
dht->c->self_public_key);
}
}
for (i = 0; i < dht->num_friends; ++i) {
if (!client_or_ip_port_in_list(dht->friends_list[i].client_list,
MAX_FRIEND_CLIENTS, client_id, ip_port)) {
if (replace_bad(dht->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(dht->friends_list[i].client_list, MAX_FRIEND_CLIENTS,
client_id, ip_port, dht->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(DHT *dht, IP_Port ip_port, uint8_t *client_id, uint8_t *nodeclient_id)
{
uint32_t i, j;
uint64_t temp_time = unix_time();
/* convert IPv4-in-IPv6 to IPv4 */
if ((ip_port.ip.family == AF_INET6) && IN6_IS_ADDR_V4MAPPED(&ip_port.ip.ip6.in6_addr)) {
ip_port.ip.family = AF_INET;
ip_port.ip.ip4.uint32 = ip_port.ip.ip6.uint32[3];
}
if (id_equal(client_id, dht->c->self_public_key)) {
for (i = 0; i < LCLIENT_LIST; ++i) {
if (id_equal(nodeclient_id, dht->close_clientlist[i].client_id)) {
if (ip_port.ip.family == AF_INET) {
dht->close_clientlist[i].assoc4.ret_ip_port = ip_port;
dht->close_clientlist[i].assoc4.ret_timestamp = temp_time;
} else if (ip_port.ip.family == AF_INET6) {
dht->close_clientlist[i].assoc6.ret_ip_port = ip_port;
dht->close_clientlist[i].assoc6.ret_timestamp = temp_time;
}
return;
}
}
} else {
for (i = 0; i < dht->num_friends; ++i) {
if (id_equal(client_id, dht->friends_list[i].client_id)) {
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
if (id_equal(nodeclient_id, dht->friends_list[i].client_list[j].client_id)) {
if (ip_port.ip.family == AF_INET) {
dht->friends_list[i].client_list[j].assoc4.ret_ip_port = ip_port;
dht->friends_list[i].client_list[j].assoc4.ret_timestamp = temp_time;
} else if (ip_port.ip.family == AF_INET6) {
dht->friends_list[i].client_list[j].assoc6.ret_ip_port = ip_port;
dht->friends_list[i].client_list[j].assoc6.ret_timestamp = temp_time;
}
return;
}
}
}
}
}
}
#define NODES_ENCRYPTED_MESSAGE_LENGTH (crypto_secretbox_NONCEBYTES + sizeof(uint64_t) + sizeof(Node_format) + sizeof(Node_format) + crypto_secretbox_MACBYTES)
/* Send a getnodes request.
sendback_node is the node that it will send back the response to (set to NULL to disable this) */
static int getnodes(DHT *dht, IP_Port ip_port, uint8_t *public_key, uint8_t *client_id, Node_format *sendback_node)
{
/* Check if packet is going to be sent to ourself. */
if (id_equal(public_key, dht->c->self_public_key))
return -1;
uint8_t plain_message[NODES_ENCRYPTED_MESSAGE_LENGTH] = {0};
uint8_t encrypted_message[NODES_ENCRYPTED_MESSAGE_LENGTH];
uint8_t nonce[crypto_box_NONCEBYTES];
new_nonce(nonce);
memcpy(encrypted_message, nonce, crypto_box_NONCEBYTES);
uint64_t temp_time = unix_time();
memcpy(plain_message, &temp_time, sizeof(temp_time));
Node_format reciever;
memcpy(reciever.client_id, public_key, CLIENT_ID_SIZE);
reciever.ip_port = ip_port;
memcpy(plain_message + sizeof(temp_time), &reciever, sizeof(reciever));
if (sendback_node != NULL)
memcpy(plain_message + sizeof(temp_time) + sizeof(reciever), sendback_node, sizeof(Node_format));
int len_m = encrypt_data_symmetric(dht->secret_symmetric_key,
nonce,
plain_message,
sizeof(temp_time) + sizeof(reciever) + sizeof(Node_format),
encrypted_message + crypto_secretbox_NONCEBYTES);
if (len_m != NODES_ENCRYPTED_MESSAGE_LENGTH - crypto_secretbox_NONCEBYTES)
return -1;
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
uint8_t plain[CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH];
uint8_t encrypt[CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
memcpy(plain, client_id, CLIENT_ID_SIZE);
memcpy(plain + CLIENT_ID_SIZE, encrypted_message, NODES_ENCRYPTED_MESSAGE_LENGTH);
int len = encrypt_data( public_key,
dht->c->self_secret_key,
nonce,
plain,
CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH,
encrypt );
if (len != CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES)
return -1;
data[0] = NET_PACKET_GET_NODES;
memcpy(data + 1, dht->c->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(dht->c->lossless_udp->net, ip_port, data, sizeof(data));
}
/* Send a send nodes response. */
/* because of BINARY compatibility, the Node_format MUST BE Node4_format,
* IPv6 nodes are sent in a different message
* encrypted_data must be of size NODES_ENCRYPTED_MESSAGE_LENGTH */
static int sendnodes(DHT *dht, IP_Port ip_port, uint8_t *public_key, uint8_t *client_id, uint8_t *encrypted_data)
{
/* Check if packet is going to be sent to ourself. */
if (id_equal(public_key, dht->c->self_public_key))
return -1;
size_t Node4_format_size = sizeof(Node4_format);
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES
+ Node4_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
Node_format nodes_list[MAX_SENT_NODES];
int num_nodes = get_close_nodes(dht, client_id, nodes_list, AF_INET, LAN_ip(ip_port.ip) == 0);
if (num_nodes == 0)
return 0;
uint8_t plain[Node4_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH];
uint8_t encrypt[Node4_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
uint8_t nonce[crypto_box_NONCEBYTES];
new_nonce(nonce);
Node4_format *nodes4_list = (Node4_format *)(plain);
int i, num_nodes_ok = 0;
for (i = 0; i < num_nodes; i++) {
memcpy(nodes4_list[num_nodes_ok].client_id, nodes_list[i].client_id, CLIENT_ID_SIZE);
nodes4_list[num_nodes_ok].ip_port.port = nodes_list[i].ip_port.port;
IP *node_ip = &nodes_list[i].ip_port.ip;
if ((node_ip->family == AF_INET6) && IN6_IS_ADDR_V4MAPPED(&node_ip->ip6.in6_addr))
/* embedded IPv4-in-IPv6 address: return it in regular sendnodes packet */
nodes4_list[num_nodes_ok].ip_port.ip.uint32 = node_ip->ip6.uint32[3];
else if (node_ip->family == AF_INET)
nodes4_list[num_nodes_ok].ip_port.ip.uint32 = node_ip->ip4.uint32;
else /* shouldn't happen */
continue;
num_nodes_ok++;
}
if (num_nodes_ok < num_nodes) {
/* shouldn't happen */
num_nodes = num_nodes_ok;
}
memcpy(plain + num_nodes * Node4_format_size, encrypted_data, NODES_ENCRYPTED_MESSAGE_LENGTH);
int len = encrypt_data( public_key,
dht->c->self_secret_key,
nonce,
plain,
num_nodes * Node4_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH,
encrypt );
if ((unsigned int)len != num_nodes * Node4_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH +
crypto_box_MACBYTES)
return -1;
data[0] = NET_PACKET_SEND_NODES;
memcpy(data + 1, dht->c->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(dht->c->lossless_udp->net, ip_port, data, 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + len);
}
/* Send a send nodes response: message for IPv6 nodes */
static int sendnodes_ipv6(DHT *dht, IP_Port ip_port, uint8_t *public_key, uint8_t *client_id, uint8_t *encrypted_data)
{
/* Check if packet is going to be sent to ourself. */
if (id_equal(public_key, dht->c->self_public_key))
return -1;
size_t Node_format_size = sizeof(Node_format);
uint8_t data[1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES
+ Node_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
Node_format nodes_list[MAX_SENT_NODES];
int num_nodes = get_close_nodes(dht, client_id, nodes_list, AF_INET6, LAN_ip(ip_port.ip) == 0);
if (num_nodes == 0)
return 0;
uint8_t plain[Node_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH];
uint8_t encrypt[Node_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES];
uint8_t nonce[crypto_box_NONCEBYTES];
new_nonce(nonce);
memcpy(plain, nodes_list, num_nodes * Node_format_size);
memcpy(plain + num_nodes * Node_format_size, encrypted_data, NODES_ENCRYPTED_MESSAGE_LENGTH);
int len = encrypt_data( public_key,
dht->c->self_secret_key,
nonce,
plain,
num_nodes * Node_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH,
encrypt );
if ((unsigned int)len != num_nodes * Node_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES)
return -1;
data[0] = NET_PACKET_SEND_NODES_IPV6;
memcpy(data + 1, dht->c->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(dht->c->lossless_udp->net, ip_port, data, 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + len);
}
static int handle_getnodes(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
if (length != ( 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH +
crypto_box_MACBYTES ))
return 1;
/* Check if packet is from ourself. */
if (id_equal(packet + 1, dht->c->self_public_key))
return 1;
uint8_t plain[CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH];
int len = decrypt_data( packet + 1,
dht->c->self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES,
plain );
if (len != CLIENT_ID_SIZE + NODES_ENCRYPTED_MESSAGE_LENGTH)
return 1;
sendnodes(dht, source, packet + 1, plain, plain + CLIENT_ID_SIZE);
sendnodes_ipv6(dht, source, packet + 1, plain,
plain + CLIENT_ID_SIZE); /* TODO: prevent possible amplification attacks */
add_toping(dht->ping, packet + 1, source);
//send_ping_request(dht, source, packet + 1); /* TODO: make this smarter? */
return 0;
}
/* return 0 if no
return 1 if yes
encrypted_data must be of size NODES_ENCRYPTED_MESSAGE_LENGTH*/
static uint8_t sent_getnode_to_node(DHT *dht, uint8_t *client_id, IP_Port node_ip_port, uint8_t *encrypted_data,
Node_format *sendback_node)
{
uint8_t plain_message[NODES_ENCRYPTED_MESSAGE_LENGTH];
if (decrypt_data_symmetric(dht->secret_symmetric_key, encrypted_data, encrypted_data + crypto_secretbox_NONCEBYTES,
NODES_ENCRYPTED_MESSAGE_LENGTH - crypto_secretbox_NONCEBYTES,
plain_message) != sizeof(uint64_t) + sizeof(Node_format) * 2)
return 0;
uint64_t comp_time;
memcpy(&comp_time, plain_message, sizeof(uint64_t));
uint64_t temp_time = unix_time();
if (comp_time + PING_TIMEOUT < temp_time || temp_time < comp_time)
return 0;
Node_format test;
memcpy(&test, plain_message + sizeof(uint64_t), sizeof(Node_format));
if (!ipport_equal(&test.ip_port, &node_ip_port) || memcmp(test.client_id, client_id, CLIENT_ID_SIZE) != 0)
return 0;
memcpy(sendback_node, plain_message + sizeof(uint64_t) + sizeof(Node_format), sizeof(Node_format));
return 1;
}
/* Function is needed in following functions. */
static int send_hardening_getnode_res(DHT *dht, Node_format *sendto, Node_format *list, uint16_t num_nodes);
static int handle_sendnodes_core(void *object, IP_Port source, uint8_t *packet, uint32_t length,
size_t node_format_size, uint8_t *plain, uint16_t plain_length, uint32_t *num_nodes_out, Node_format *sendback_node)
{
if (plain_length != MAX_SENT_NODES * node_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH)
return 1;
DHT *dht = object;
uint32_t cid_size = 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES;
if (length <= cid_size) /* too short */
return 1;
uint32_t data_size = length - cid_size;
if ((data_size % node_format_size) != 0) /* invalid length */
return 1;
uint32_t num_nodes = data_size / node_format_size;
if (num_nodes > MAX_SENT_NODES) /* too long */
return 1;
int len = decrypt_data(
packet + 1,
dht->c->self_secret_key,
packet + 1 + CLIENT_ID_SIZE,
packet + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES,
num_nodes * node_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH + crypto_box_MACBYTES,
plain);
if ((unsigned int)len != num_nodes * node_format_size + NODES_ENCRYPTED_MESSAGE_LENGTH)
return 1;
if (!sent_getnode_to_node(dht, packet + 1, source, plain + num_nodes * node_format_size, sendback_node))
return 1;
/* store the address the *request* was sent to */
addto_lists(dht, source, packet + 1);
*num_nodes_out = num_nodes;
return 0;
}
static int handle_sendnodes(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
size_t node4_format_size = sizeof(Node4_format);
uint8_t plain[node4_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH];
uint32_t num_nodes;
Node_format sendback_node;
if (handle_sendnodes_core(object, source, packet, length, node4_format_size, plain, sizeof(plain), &num_nodes,
&sendback_node))
return 1;
Node4_format *nodes4_list = (Node4_format *)(plain);
uint32_t i;
IP_Port ipp;
ipp.ip.family = AF_INET;
Node_format nodes_list[MAX_SENT_NODES];
for (i = 0; i < num_nodes; i++)
if ((nodes4_list[i].ip_port.ip.uint32 != 0) && (nodes4_list[i].ip_port.ip.uint32 != (uint32_t)~0)) {
ipp.ip.ip4.uint32 = nodes4_list[i].ip_port.ip.uint32;
ipp.port = nodes4_list[i].ip_port.port;
send_ping_request(dht->ping, ipp, nodes4_list[i].client_id);
returnedip_ports(dht, ipp, nodes4_list[i].client_id, packet + 1);
memcpy(nodes_list[i].client_id, nodes4_list[i].client_id, CLIENT_ID_SIZE);
ipport_copy(&nodes_list[i].ip_port, &ipp);
}
send_hardening_getnode_res(dht, &sendback_node, nodes_list, num_nodes);
return 0;
}
static int handle_sendnodes_ipv6(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
size_t node_format_size = sizeof(Node_format);
uint8_t plain[node_format_size * MAX_SENT_NODES + NODES_ENCRYPTED_MESSAGE_LENGTH];
uint32_t num_nodes;
Node_format sendback_node;
if (handle_sendnodes_core(object, source, packet, length, node_format_size, plain, sizeof(plain), &num_nodes,
&sendback_node))
return 1;
Node_format *nodes_list = (Node_format *)(plain);
uint32_t i;
send_hardening_getnode_res(dht, &sendback_node, nodes_list, num_nodes);
for (i = 0; i < num_nodes; i++)
if (ipport_isset(&nodes_list[i].ip_port)) {
send_ping_request(dht->ping, nodes_list[i].ip_port, nodes_list[i].client_id);
returnedip_ports(dht, nodes_list[i].ip_port, nodes_list[i].client_id, packet + 1);
}
return 0;
}
/*----------------------------------------------------------------------------------*/
/*------------------------END of packet handling functions--------------------------*/
/*
* Send get nodes requests with client_id to max_num peers in list of length length
*/
static void get_bunchnodes(DHT *dht, Client_data *list, uint16_t length, uint16_t max_num, uint8_t *client_id)
{
uint32_t i, num = 0;
for (i = 0; i < length; ++i) {
IPPTsPng *assoc;
uint32_t a;
for (a = 0, assoc = &list[i].assoc6; a < 2; a++, assoc = &list[i].assoc4)
if (ipport_isset(&(assoc->ip_port)) &&
!is_timeout(assoc->ret_timestamp, BAD_NODE_TIMEOUT)) {
getnodes(dht, assoc->ip_port, list[i].client_id, client_id, NULL);
++num;
if (num >= max_num)
return;
}
}
}
int DHT_addfriend(DHT *dht, uint8_t *client_id)
{
if (friend_number(dht, client_id) != -1) /* Is friend already in DHT? */
return 1;
DHT_Friend *temp;
temp = realloc(dht->friends_list, sizeof(DHT_Friend) * (dht->num_friends + 1));
if (temp == NULL)
return 1;
dht->friends_list = temp;
memset(&dht->friends_list[dht->num_friends], 0, sizeof(DHT_Friend));
memcpy(dht->friends_list[dht->num_friends].client_id, client_id, CLIENT_ID_SIZE);
dht->friends_list[dht->num_friends].nat.NATping_id = ((uint64_t)random_int() << 32) + random_int();
++dht->num_friends;
get_bunchnodes(dht, dht->close_clientlist, LCLIENT_LIST, MAX_FRIEND_CLIENTS, client_id);/*TODO: make this better?*/
return 0;
}
int DHT_delfriend(DHT *dht, uint8_t *client_id)
{
uint32_t i;
DHT_Friend *temp;
for (i = 0; i < dht->num_friends; ++i) {
/* Equal */
if (id_equal(dht->friends_list[i].client_id, client_id)) {
--dht->num_friends;
if (dht->num_friends != i) {
memcpy( dht->friends_list[i].client_id,
dht->friends_list[dht->num_friends].client_id,
CLIENT_ID_SIZE );
}
if (dht->num_friends == 0) {
free(dht->friends_list);
dht->friends_list = NULL;
return 0;
}
temp = realloc(dht->friends_list, sizeof(DHT_Friend) * (dht->num_friends));
if (temp == NULL)
return 1;
dht->friends_list = temp;
return 0;
}
}
return 1;
}
/* TODO: Optimize this. */
int DHT_getfriendip(DHT *dht, uint8_t *client_id, IP_Port *ip_port)
{
uint32_t i, j;
ip_reset(&ip_port->ip);
ip_port->port = 0;
for (i = 0; i < dht->num_friends; ++i) {
/* Equal */
if (id_equal(dht->friends_list[i].client_id, client_id)) {
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
Client_data *client = &dht->friends_list[i].client_list[j];
if (id_equal(client->client_id, client_id)) {
IPPTsPng *assoc = NULL;
uint32_t a;
for (a = 0, assoc = &client->assoc6; a < 2; a++, assoc = &client->assoc4)
if (!is_timeout(assoc->timestamp, BAD_NODE_TIMEOUT)) {
*ip_port = assoc->ip_port;
return 1;
}
}
}
return 0;
}
}
return -1;
}
static void do_ping_and_sendnode_requests(DHT *dht, uint64_t *lastgetnode, uint8_t *client_id,
Client_data *list, uint32_t list_count)
{
uint32_t i;
uint64_t temp_time = unix_time();
uint32_t num_nodes = 0;
Client_data *client_list[list_count * 2];
IPPTsPng *assoc_list[list_count * 2];
for (i = 0; i < list_count; i++) {
/* If node is not dead. */
Client_data *client = &list[i];
IPPTsPng *assoc;
uint32_t a;
for (a = 0, assoc = &client->assoc6; a < 2; a++, assoc = &client->assoc4)
if (!is_timeout(assoc->timestamp, KILL_NODE_TIMEOUT)) {
if (is_timeout(assoc->last_pinged, PING_INTERVAL)) {
send_ping_request(dht->ping, assoc->ip_port, client->client_id );
assoc->last_pinged = temp_time;
}
/* If node is good. */
if (!is_timeout(assoc->timestamp, BAD_NODE_TIMEOUT)) {
client_list[num_nodes] = client;
assoc_list[num_nodes] = assoc;
++num_nodes;
}
}
}
if ((num_nodes != 0) && is_timeout(*lastgetnode, GET_NODE_INTERVAL)) {
uint32_t rand_node = rand() % num_nodes;
getnodes(dht, assoc_list[rand_node]->ip_port, client_list[rand_node]->client_id,
client_id, NULL);
*lastgetnode = temp_time;
}
}
/* Ping each client in the "friends" list every PING_INTERVAL seconds. Send a get nodes request
* every GET_NODE_INTERVAL seconds to a random good node for each "friend" in our "friends" list.
*/
static void do_DHT_friends(DHT *dht)
{
uint32_t i;
for (i = 0; i < dht->num_friends; ++i)
do_ping_and_sendnode_requests(dht, &dht->friends_list[i].lastgetnode, dht->friends_list[i].client_id,
dht->friends_list[i].client_list, MAX_FRIEND_CLIENTS);
}
/* Ping each client in the close nodes list every PING_INTERVAL seconds.
* Send a get nodes request every GET_NODE_INTERVAL seconds to a random good node in the list.
*/
static void do_Close(DHT *dht)
{
do_ping_and_sendnode_requests(dht, &dht->close_lastgetnodes, dht->c->self_public_key,
dht->close_clientlist, LCLIENT_LIST);
}
void DHT_bootstrap(DHT *dht, IP_Port ip_port, uint8_t *public_key)
{
getnodes(dht, ip_port, public_key, dht->c->self_public_key, NULL);
}
int DHT_bootstrap_from_address(DHT *dht, const char *address, uint8_t ipv6enabled,
uint16_t port, uint8_t *public_key)
{
IP_Port ip_port_v64;
IP *ip_extra = NULL;
IP_Port ip_port_v4;
ip_init(&ip_port_v64.ip, ipv6enabled);
if (ipv6enabled) {
/* setup for getting BOTH: an IPv6 AND an IPv4 address */
ip_port_v64.ip.family = AF_UNSPEC;
ip_reset(&ip_port_v4.ip);
ip_extra = &ip_port_v4.ip;
}
if (addr_resolve_or_parse_ip(address, &ip_port_v64.ip, ip_extra)) {
ip_port_v64.port = port;
DHT_bootstrap(dht, ip_port_v64, public_key);
if ((ip_extra != NULL) && ip_isset(ip_extra)) {
ip_port_v4.port = port;
DHT_bootstrap(dht, ip_port_v4, public_key);
}
return 1;
} else
return 0;
}
/* 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)
{
uint32_t i;
for (i = 0; i < LCLIENT_LIST; ++i) {
if (id_equal(client_id, dht->close_clientlist[i].client_id)) {
Client_data *client = &dht->close_clientlist[i];
if (ip_isset(&client->assoc6.ip_port.ip))
return sendpacket(dht->c->lossless_udp->net, client->assoc6.ip_port, packet, length);
else if (ip_isset(&client->assoc4.ip_port.ip))
return sendpacket(dht->c->lossless_udp->net, client->assoc4.ip_port, packet, length);
else
break;
}
}
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.
*
* return the number of ips returned.
* return 0 if we are connected to friend or if no ips were found.
* return -1 if no such friend.
*/
static int friend_iplist(DHT *dht, IP_Port *ip_portlist, uint16_t friend_num)
{
if (friend_num >= dht->num_friends)
return -1;
DHT_Friend *friend = &dht->friends_list[friend_num];
Client_data *client;
IP_Port ipv4s[MAX_FRIEND_CLIENTS];
int num_ipv4s = 0;
IP_Port ipv6s[MAX_FRIEND_CLIENTS];
int num_ipv6s = 0;
uint8_t connected;
int i;
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
client = &(friend->client_list[i]);
connected = 0;
/* If ip is not zero and node is good. */
if (ip_isset(&client->assoc4.ret_ip_port.ip) && !is_timeout(client->assoc4.ret_timestamp, BAD_NODE_TIMEOUT)) {
ipv4s[num_ipv4s] = client->assoc4.ret_ip_port;
++num_ipv4s;
connected = 1;
}
if (ip_isset(&client->assoc6.ret_ip_port.ip) && !is_timeout(client->assoc6.ret_timestamp, BAD_NODE_TIMEOUT)) {
ipv6s[num_ipv6s] = client->assoc6.ret_ip_port;
++num_ipv6s;
connected = 1;
}
if (connected && id_equal(client->client_id, friend->client_id))
return 0; /* direct connectivity */
}
#ifdef FRIEND_IPLIST_PAD
memcpy(ip_portlist, ipv6s, num_ipv6s * sizeof(IP_Port));
if (num_ipv6s == MAX_FRIEND_CLIENTS)
return MAX_FRIEND_CLIENTS;
int num_ipv4s_used = MAX_FRIEND_CLIENTS - num_ipv6s;
if (num_ipv4s_used > num_ipv4s)
num_ipv4s_used = num_ipv4s;
memcpy(&ip_portlist[num_ipv6s], ipv4s, num_ipv4s_used * sizeof(IP_Port));
return num_ipv6s + num_ipv4s_used;
#else /* !FRIEND_IPLIST_PAD */
/* there must be some secret reason why we can't pad the longer list
* with the shorter one...
*/
if (num_ipv6s >= num_ipv4s) {
memcpy(ip_portlist, ipv6s, num_ipv6s * sizeof(IP_Port));
return num_ipv6s;
}
memcpy(ip_portlist, ipv4s, num_ipv4s * sizeof(IP_Port));
return num_ipv4s;
#endif /* !FRIEND_IPLIST_PAD */
}
/* Send the following packet to everyone who tells us they are connected to friend_id.
*
* return ip for friend.
* return number of nodes the packet was sent to. (Only works if more than (MAX_FRIEND_CLIENTS / 2).
*/
int route_tofriend(DHT *dht, uint8_t *friend_id, uint8_t *packet, uint32_t length)
{
int num = friend_number(dht, friend_id);
if (num == -1)
return 0;
uint32_t i, sent = 0;
uint8_t friend_sent[MAX_FRIEND_CLIENTS] = {0};
IP_Port ip_list[MAX_FRIEND_CLIENTS];
int ip_num = friend_iplist(dht, ip_list, num);
if (ip_num < (MAX_FRIEND_CLIENTS / 2))
return 0; /* Reason for that? */
DHT_Friend *friend = &dht->friends_list[num];
Client_data *client;
/* extra legwork, because having the outside allocating the space for us
* is *usually* good(tm) (bites us in the behind in this case though) */
uint32_t a;
for (a = 0; a < 2; a++)
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
if (friend_sent[i])/* Send one packet per client.*/
continue;
client = &friend->client_list[i];
IPPTsPng *assoc = NULL;
if (!a)
assoc = &client->assoc4;
else
assoc = &client->assoc6;
/* If ip is not zero and node is good. */
if (ip_isset(&assoc->ret_ip_port.ip) &&
!is_timeout(assoc->ret_timestamp, BAD_NODE_TIMEOUT)) {
int retval = sendpacket(dht->c->lossless_udp->net, assoc->ip_port, packet, length);
if ((unsigned int)retval == length) {
++sent;
friend_sent[i] = 1;
}
}
}
return sent;
}
/* Send the following packet to one random person who tells us they are connected to friend_id.
*
* return number of nodes the packet was sent to.
*/
static int routeone_tofriend(DHT *dht, uint8_t *friend_id, uint8_t *packet, uint32_t length)
{
int num = friend_number(dht, friend_id);
if (num == -1)
return 0;
DHT_Friend *friend = &dht->friends_list[num];
Client_data *client;
IP_Port ip_list[MAX_FRIEND_CLIENTS * 2];
int n = 0;
uint32_t i;
/* extra legwork, because having the outside allocating the space for us
* is *usually* good(tm) (bites us in the behind in this case though) */
uint32_t a;
for (a = 0; a < 2; a++)
for (i = 0; i < MAX_FRIEND_CLIENTS; ++i) {
client = &friend->client_list[i];
IPPTsPng *assoc = NULL;
if (!a)
assoc = &client->assoc4;
else
assoc = &client->assoc6;
/* If ip is not zero and node is good. */
if (ip_isset(&assoc->ret_ip_port.ip) && !is_timeout(assoc->ret_timestamp, BAD_NODE_TIMEOUT)) {
ip_list[n] = assoc->ip_port;
++n;
}
}
if (n < 1)
return 0;
int retval = sendpacket(dht->c->lossless_udp->net, ip_list[rand() % n], packet, length);
if ((unsigned int)retval == 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.
*
* return number of ips returned.
* return 0 if we are connected to friend or if no ips were found.
* return -1 if no such friend.
*/
int friend_ips(DHT *dht, IP_Port *ip_portlist, uint8_t *friend_id)
{
uint32_t i;
for (i = 0; i < dht->num_friends; ++i) {
/* Equal */
if (id_equal(dht->friends_list[i].client_id, friend_id))
return friend_iplist(dht, ip_portlist, i);
}
return -1;
}
/*----------------------------------------------------------------------------------*/
/*---------------------BEGINNING OF NAT PUNCHING FUNCTIONS--------------------------*/
static int send_NATping(DHT *dht, 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(dht->c->self_public_key, dht->c->self_secret_key, packet, public_key, data,
sizeof(uint64_t) + 1, CRYPTO_PACKET_NAT_PING);
if (len == -1)
return -1;
if (type == 0) /* If packet is request use many people to route it. */
num = route_tofriend(dht, public_key, packet, len);
else if (type == 1) /* If packet is response use only one person to route it */
num = routeone_tofriend(dht, public_key, packet, len);
if (num == 0)
return -1;
return num;
}
/* Handle a received ping request for. */
static int handle_NATping(void *object, IP_Port source, uint8_t *source_pubkey, uint8_t *packet, uint32_t length)
{
if (length != sizeof(uint64_t) + 1)
return 1;
DHT *dht = object;
uint64_t ping_id;
memcpy(&ping_id, packet + 1, sizeof(uint64_t));
int friendnumber = friend_number(dht, source_pubkey);
if (friendnumber == -1)
return 1;
DHT_Friend *friend = &dht->friends_list[friendnumber];
if (packet[0] == NAT_PING_REQUEST) {
/* 1 is reply */
send_NATping(dht, source_pubkey, ping_id, NAT_PING_RESPONSE);
friend->nat.recvNATping_timestamp = unix_time();
return 0;
} else if (packet[0] == NAT_PING_RESPONSE) {
if (friend->nat.NATping_id == ping_id) {
friend->nat.NATping_id = ((uint64_t)random_int() << 32) + random_int();
friend->nat.hole_punching = 1;
return 0;
}
}
return 1;
}
/* 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;
ip_reset(&zero);
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_equal(&ip_portlist[i].ip, &ip_portlist[j].ip))
++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.
*
* return 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_equal(&ip_portlist[i].ip, &ip)) {
portlist[num] = ntohs(ip_portlist[i].port);
++num;
}
}
return num;
}
static void punch_holes(DHT *dht, 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 = dht->friends_list[friend_num].nat.punching_index + MAX_PUNCHING_PORTS;
uint16_t firstport = port_list[0];
for (i = 0; i < numports; ++i) {
if (firstport != port_list[0])
break;
}
if (i == numports) { /* If all ports are the same, only try that one port. */
IP_Port pinging;
ip_copy(&pinging.ip, &ip);
pinging.port = htons(firstport);
send_ping_request(dht->ping, pinging, dht->friends_list[friend_num].client_id);
} else {
for (i = dht->friends_list[friend_num].nat.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_copy(&pinging.ip, &ip);
pinging.port = htons(port);
send_ping_request(dht->ping, pinging, dht->friends_list[friend_num].client_id);
}
dht->friends_list[friend_num].nat.punching_index = i;
}
}
static void do_NAT(DHT *dht)
{
uint32_t i;
uint64_t temp_time = unix_time();
for (i = 0; i < dht->num_friends; ++i) {
IP_Port ip_list[MAX_FRIEND_CLIENTS];
int num = friend_iplist(dht, 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 (dht->friends_list[i].nat.NATping_timestamp + PUNCH_INTERVAL < temp_time) {
send_NATping(dht, dht->friends_list[i].client_id, dht->friends_list[i].nat.NATping_id, NAT_PING_REQUEST);
dht->friends_list[i].nat.NATping_timestamp = temp_time;
}
if (dht->friends_list[i].nat.hole_punching == 1 &&
dht->friends_list[i].nat.punching_timestamp + PUNCH_INTERVAL < temp_time &&
dht->friends_list[i].nat.recvNATping_timestamp + PUNCH_INTERVAL * 2 >= temp_time) {
IP ip = NAT_commonip(ip_list, num, MAX_FRIEND_CLIENTS / 2);
if (!ip_isset(&ip))
continue;
uint16_t port_list[MAX_FRIEND_CLIENTS];
uint16_t numports = NAT_getports(port_list, ip_list, num, ip);
punch_holes(dht, ip, port_list, numports, i);
dht->friends_list[i].nat.punching_timestamp = temp_time;
dht->friends_list[i].nat.hole_punching = 0;
}
}
}
/*----------------------------------------------------------------------------------*/
/*-----------------------END OF NAT PUNCHING FUNCTIONS------------------------------*/
#define HARDREQ_DATA_SIZE 768 /* Attempt to prevent amplification/other attacks*/
#define CHECK_TYPE_ROUTE_REQ 0
#define CHECK_TYPE_ROUTE_RES 1
#define CHECK_TYPE_GETNODE_REQ 2
#define CHECK_TYPE_GETNODE_RES 3
#define CHECK_TYPE_TEST_REQ 4
#define CHECK_TYPE_TEST_RES 5
static int send_hardening_req(DHT *dht, Node_format *sendto, uint8_t type, uint8_t *contents, uint16_t length)
{
if (length > HARDREQ_DATA_SIZE - 1)
return -1;
uint8_t packet[MAX_DATA_SIZE];
uint8_t data[HARDREQ_DATA_SIZE] = {0};
data[0] = type;
memcpy(data + 1, contents, length);
int len = create_request(dht->c->self_public_key, dht->c->self_secret_key, packet, sendto->client_id, data,
sizeof(data), CRYPTO_PACKET_HARDENING);
if (len == -1)
return -1;
return sendpacket(dht->c->lossless_udp->net, sendto->ip_port, packet, len);
}
/* Send a get node hardening request */
static int send_hardening_getnode_req(DHT *dht, Node_format *dest, Node_format *node_totest, uint8_t *search_id)
{
uint8_t data[sizeof(Node_format) + CLIENT_ID_SIZE];
memcpy(data, node_totest, sizeof(Node_format));
memcpy(data + sizeof(Node_format), search_id, CLIENT_ID_SIZE);
return send_hardening_req(dht, dest, CHECK_TYPE_GETNODE_REQ, data, sizeof(Node_format) + CLIENT_ID_SIZE);
}
/* Send a get node hardening response */
static int send_hardening_getnode_res(DHT *dht, Node_format *sendto, Node_format *list, uint16_t num_nodes)
{
if (!ip_isset(&sendto->ip_port.ip))
return -1;
uint8_t packet[MAX_DATA_SIZE];
uint8_t data[1 + num_nodes * sizeof(Node_format)];
data[0] = CHECK_TYPE_GETNODE_RES;
memcpy(data + 1, list, num_nodes * sizeof(Node_format));
int len = create_request(dht->c->self_public_key, dht->c->self_secret_key, packet, sendto->client_id, data,
sizeof(data), CRYPTO_PACKET_HARDENING);
if (len == -1)
return -1;
return sendpacket(dht->c->lossless_udp->net, sendto->ip_port, packet, len);
}
/*
* check how many nodes in nodes are also present in the closelist.
* TODO: make this function better.
*/
static int have_nodes_closelist(DHT *dht, Node_format *nodes, uint16_t num, sa_family_t sa_family)
{
Node_format nodes_list[MAX_SENT_NODES];
int num_nodes = get_close_nodes(dht, dht->c->self_public_key, nodes_list, sa_family, 1);
if (num_nodes < 1)
return -1;
int counter = 0;
uint32_t i, j;
for (i = 0; i < num; ++i) {
if (id_equal(nodes[i].client_id, dht->c->self_public_key)) {
++counter;
}
for (j = 0; j < (uint32_t)num_nodes; ++j) {
if (id_equal(nodes[i].client_id, nodes_list[j].client_id)) {
if (ipport_equal(&nodes[i].ip_port, &nodes_list[j].ip_port)) {
++counter;
break;
}
}
}
}
return counter;
}
/* TODO: improve */
static IPPTsPng *get_closelist_IPPTsPng(DHT *dht, uint8_t *client_id, sa_family_t sa_family)
{
uint32_t i;
for (i = 0; i < LCLIENT_LIST; ++i) {
if (memcmp(dht->close_clientlist[i].client_id, client_id, CLIENT_ID_SIZE) != 0)
continue;
if (sa_family == AF_INET)
return &dht->close_clientlist[i].assoc4;
else if (sa_family == AF_INET6)
return &dht->close_clientlist[i].assoc6;
}
return NULL;
}
/* Interval in seconds between hardening checks */
#define HARDENING_INTERVAL 5
#define HARDEN_TIMEOUT 500
/* Handle a received hardening packet */
static int handle_hardening(void *object, IP_Port source, uint8_t *source_pubkey, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
if (length < 2) {
return 1;
}
switch (packet[0]) {
case CHECK_TYPE_GETNODE_REQ: {
if (length != HARDREQ_DATA_SIZE)
return 1;
Node_format node, tocheck_node;
node.ip_port = source;
memcpy(node.client_id, source_pubkey, CLIENT_ID_SIZE);
memcpy(&tocheck_node, packet + 1, sizeof(Node_format));
if (getnodes(dht, tocheck_node.ip_port, tocheck_node.client_id, packet + 1 + sizeof(Node_format), &node) == -1)
return 1;
return 0;
}
case CHECK_TYPE_GETNODE_RES: {
if ((length - 1) % sizeof(Node_format) != 0)
return 1;
uint16_t num = (length - 1) / sizeof(Node_format);
/* TODO: MAX_SENT_NODES nodes should be returned at all times
(right now we have a small network size so it could cause problems for testing and etc..) */
if (num > MAX_SENT_NODES || num == 0)
return 1;
Node_format nodes[num];
memcpy(nodes, packet + 1, sizeof(Node_format)*num);
/* NOTE: This should work for now but should be changed to something better. */
if (have_nodes_closelist(dht, nodes, num, nodes[0].ip_port.ip.family) < (num + 1) / 2)
return 1;
IPPTsPng *temp = get_closelist_IPPTsPng(dht, source_pubkey, source.ip.family);
if (temp == NULL)
return 1;
if (is_timeout(temp->hardening.send_nodes_timestamp, HARDENING_INTERVAL))
return 1;
if (memcmp(temp->hardening.send_nodes_pingedid, source_pubkey, CLIENT_ID_SIZE) != 0)
return 1;
/* If Nodes look good and the request checks out */
temp->hardening.send_nodes_ok = 1;
return 0;/* success*/
}
}
return 1;
}
/* Return a random node from all the nodes we are connected to.
* TODO: improve this function.
*/
Node_format random_node(DHT *dht, sa_family_t sa_family)
{
uint8_t id[CLIENT_ID_SIZE];
uint32_t i;
for (i = 0; i < CLIENT_ID_SIZE / 4; ++i) { /* populate the id with pseudorandom bytes.*/
uint32_t t = rand();
memcpy(id + i * sizeof(t), &t, sizeof(t));
}
Node_format nodes_list[MAX_SENT_NODES];
memset(nodes_list, 0, sizeof(nodes_list));
int num_nodes = get_close_nodes(dht, id, nodes_list, sa_family, 1);
if (num_nodes < 1)
return nodes_list[0];
else
return nodes_list[rand() % num_nodes];
}
void do_hardening(DHT *dht)
{
uint32_t i;
for (i = 0; i < LCLIENT_LIST * 2; ++i) {
IPPTsPng *cur_iptspng;
sa_family_t sa_family;
uint8_t *client_id = dht->close_clientlist[i / 2].client_id;
if (i % 2 == 0) {
cur_iptspng = &dht->close_clientlist[i / 2].assoc4;
sa_family = AF_INET;
} else {
cur_iptspng = &dht->close_clientlist[i / 2].assoc6;
sa_family = AF_INET6;
}
if (is_timeout(cur_iptspng->timestamp, BAD_NODE_TIMEOUT))
continue;
if (cur_iptspng->hardening.send_nodes_ok == 0) {
if (is_timeout(cur_iptspng->hardening.send_nodes_timestamp, HARDENING_INTERVAL)) {
Node_format rand_node = random_node(dht, sa_family);
if (!ipport_isset(&rand_node.ip_port))
continue;
Node_format to_test;
to_test.ip_port = cur_iptspng->ip_port;
memcpy(to_test.client_id, client_id, CLIENT_ID_SIZE);
//TODO: The search id should maybe not be ours?
if (send_hardening_getnode_req(dht, &rand_node, &to_test, dht->c->self_public_key) != -1) {
memcpy(cur_iptspng->hardening.send_nodes_pingedid, rand_node.client_id, CLIENT_ID_SIZE);
cur_iptspng->hardening.send_nodes_timestamp = unix_time();
}
}
} else {
if (is_timeout(cur_iptspng->hardening.send_nodes_timestamp, HARDEN_TIMEOUT)) {
cur_iptspng->hardening.send_nodes_ok = 0;
}
}
//TODO: add the 2 other testers.
}
}
/*----------------------------------------------------------------------------------*/
DHT *new_DHT(Net_Crypto *c)
{
/* init time */
unix_time_update();
if (c == NULL)
return NULL;
DHT *dht = calloc(1, sizeof(DHT));
if (dht == NULL)
return NULL;
dht->ping = new_ping(dht, c);
if (dht->ping == NULL) {
kill_DHT(dht);
return NULL;
}
dht->c = c;
networking_registerhandler(c->lossless_udp->net, NET_PACKET_GET_NODES, &handle_getnodes, dht);
networking_registerhandler(c->lossless_udp->net, NET_PACKET_SEND_NODES, &handle_sendnodes, dht);
networking_registerhandler(c->lossless_udp->net, NET_PACKET_SEND_NODES_IPV6, &handle_sendnodes_ipv6, dht);
init_cryptopackets(dht);
cryptopacket_registerhandler(c, CRYPTO_PACKET_NAT_PING, &handle_NATping, dht);
cryptopacket_registerhandler(c, CRYPTO_PACKET_HARDENING, &handle_hardening, dht);
new_symmetric_key(dht->secret_symmetric_key);
return dht;
}
void do_DHT(DHT *dht)
{
unix_time_update();
do_Close(dht);
do_DHT_friends(dht);
do_NAT(dht);
do_toping(dht->ping);
do_hardening(dht);
}
void kill_DHT(DHT *dht)
{
kill_ping(dht->ping);
free(dht->friends_list);
free(dht);
}
/* new DHT format for load/save, more robust and forward compatible */
#define DHT_STATE_COOKIE_GLOBAL 0x159000d
#define DHT_STATE_COOKIE_TYPE 0x11ce
#define DHT_STATE_TYPE_FRIENDS_ASSOC46 3
#define DHT_STATE_TYPE_CLIENTS_ASSOC46 4
/* Get the size of the DHT (for saving). */
uint32_t DHT_size(DHT *dht)
{
uint32_t num = 0, i;
for (i = 0; i < LCLIENT_LIST; ++i)
if ((dht->close_clientlist[i].assoc4.timestamp != 0) ||
(dht->close_clientlist[i].assoc6.timestamp != 0))
num++;
uint32_t size32 = sizeof(uint32_t), sizesubhead = size32 * 2;
return size32
+ sizesubhead + sizeof(DHT_Friend) * dht->num_friends
+ sizesubhead + sizeof(Client_data) * num;
}
static uint8_t *z_state_save_subheader(uint8_t *data, uint32_t len, uint16_t type)
{
uint32_t *data32 = (uint32_t *)data;
data32[0] = len;
data32[1] = (DHT_STATE_COOKIE_TYPE << 16) | type;
data += sizeof(uint32_t) * 2;
return data;
}
/* Save the DHT in data where data is an array of size DHT_size(). */
void DHT_save(DHT *dht, uint8_t *data)
{
uint32_t len;
uint16_t type;
*(uint32_t *)data = DHT_STATE_COOKIE_GLOBAL;
data += sizeof(uint32_t);
len = sizeof(DHT_Friend) * dht->num_friends;
type = DHT_STATE_TYPE_FRIENDS_ASSOC46;
data = z_state_save_subheader(data, len, type);
memcpy(data, dht->friends_list, len);
data += len;
uint32_t num = 0, i;
for (i = 0; i < LCLIENT_LIST; ++i)
if ((dht->close_clientlist[i].assoc4.timestamp != 0) ||
(dht->close_clientlist[i].assoc6.timestamp != 0))
num++;
len = num * sizeof(Client_data);
type = DHT_STATE_TYPE_CLIENTS_ASSOC46;
data = z_state_save_subheader(data, len, type);
if (num) {
Client_data *clients = (Client_data *)data;
for (num = 0, i = 0; i < LCLIENT_LIST; ++i)
if ((dht->close_clientlist[i].assoc4.timestamp != 0) ||
(dht->close_clientlist[i].assoc6.timestamp != 0))
memcpy(&clients[num++], &dht->close_clientlist[i], sizeof(Client_data));
}
data += len;
}
static int dht_load_state_callback(void *outer, uint8_t *data, uint32_t length, uint16_t type)
{
DHT *dht = outer;
uint32_t num, i, j;
switch (type) {
case DHT_STATE_TYPE_FRIENDS_ASSOC46:
if (length % sizeof(DHT_Friend) != 0)
break;
{ /* localize declarations */
DHT_Friend *friend_list = (DHT_Friend *)data;
num = length / sizeof(DHT_Friend);
for (i = 0; i < num; ++i) {
DHT_addfriend(dht, friend_list[i].client_id);
for (j = 0; j < MAX_FRIEND_CLIENTS; ++j) {
Client_data *client = &friend_list[i].client_list[j];
if (client->assoc4.timestamp != 0)
getnodes(dht, client->assoc4.ip_port, client->client_id, friend_list[i].client_id, NULL);
if (client->assoc6.timestamp != 0)
getnodes(dht, client->assoc6.ip_port, client->client_id, friend_list[i].client_id, NULL);
}
}
} /* localize declarations */
break;
case DHT_STATE_TYPE_CLIENTS_ASSOC46:
if ((length % sizeof(Client_data)) != 0)
break;
{ /* localize declarations */
num = length / sizeof(Client_data);
Client_data *client_list = (Client_data *)data;
for (i = 0; i < num; ++i) {
if (client_list[i].assoc4.timestamp != 0)
DHT_bootstrap(dht, client_list[i].assoc4.ip_port, client_list[i].client_id);
if (client_list[i].assoc6.timestamp != 0)
DHT_bootstrap(dht, client_list[i].assoc6.ip_port, client_list[i].client_id);
}
} /* localize declarations */
break;
#ifdef DEBUG
default:
fprintf(stderr, "Load state (DHT): contains unrecognized part (len %u, type %u)\n",
length, type);
break;
#endif
}
return 0;
}
/* Load the DHT from data of size size.
*
* return -1 if failure.
* return 0 if success.
*/
int DHT_load_new(DHT *dht, uint8_t *data, uint32_t length)
{
uint32_t cookie_len = sizeof(uint32_t);
if (length > cookie_len) {
uint32_t *data32 = (uint32_t *)data;
if (data32[0] == DHT_STATE_COOKIE_GLOBAL)
return load_state(dht_load_state_callback, dht, data + cookie_len,
length - cookie_len, DHT_STATE_COOKIE_TYPE);
}
return -1;
}
/* return 0 if we are not connected to the DHT.
* return 1 if we are.
*/
int DHT_isconnected(DHT *dht)
{
uint32_t i;
unix_time_update();
for (i = 0; i < LCLIENT_LIST; ++i) {
Client_data *client = &dht->close_clientlist[i];
if (!is_timeout(client->assoc4.timestamp, BAD_NODE_TIMEOUT) ||
!is_timeout(client->assoc6.timestamp, BAD_NODE_TIMEOUT))
return 1;
}
return 0;
}