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/*
* ping.c -- Buffered pinging using cyclic arrays.
*
* This file is donated to the Tox Project.
* Copyright 2013 plutooo
*
* 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/>.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdint.h>
#include "DHT.h"
#include "ping.h"
#include "network.h"
#include "util.h"
#include "ping_array.h"
#define PING_NUM_MAX 512
/* Maximum newly announced nodes to ping per TIME_TO_PING seconds. */
#define MAX_TO_PING 16
/* Ping newly announced nodes to ping per TIME_TO_PING seconds*/
#define TIME_TO_PING 4
struct PING {
DHT *dht;
Ping_Array ping_array;
Node_format to_ping[MAX_TO_PING];
uint64_t last_to_ping;
};
#define PING_PLAIN_SIZE (1 + sizeof(uint64_t))
#define DHT_PING_SIZE (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + PING_PLAIN_SIZE + crypto_box_MACBYTES)
#define PING_DATA_SIZE (crypto_box_PUBLICKEYBYTES + sizeof(IP_Port))
int send_ping_request(PING *ping, IP_Port ipp, const uint8_t *public_key)
{
uint8_t pk[DHT_PING_SIZE];
int rc;
uint64_t ping_id;
if (id_equal(public_key, ping->dht->self_public_key))
return 1;
uint8_t shared_key[crypto_box_BEFORENMBYTES];
// generate key to encrypt ping_id with recipient privkey
DHT_get_shared_key_sent(ping->dht, shared_key, public_key);
// Generate random ping_id.
uint8_t data[PING_DATA_SIZE];
id_copy(data, public_key);
memcpy(data + crypto_box_PUBLICKEYBYTES, &ipp, sizeof(IP_Port));
ping_id = ping_array_add(&ping->ping_array, data, sizeof(data));
if (ping_id == 0)
return 1;
uint8_t ping_plain[PING_PLAIN_SIZE];
ping_plain[0] = NET_PACKET_PING_REQUEST;
memcpy(ping_plain + 1, &ping_id, sizeof(ping_id));
pk[0] = NET_PACKET_PING_REQUEST;
id_copy(pk + 1, ping->dht->self_public_key); // Our pubkey
new_nonce(pk + 1 + crypto_box_PUBLICKEYBYTES); // Generate new nonce
rc = encrypt_data_symmetric(shared_key,
pk + 1 + crypto_box_PUBLICKEYBYTES,
ping_plain, sizeof(ping_plain),
pk + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES);
if (rc != PING_PLAIN_SIZE + crypto_box_MACBYTES)
return 1;
return sendpacket(ping->dht->net, ipp, pk, sizeof(pk));
}
static int send_ping_response(PING *ping, IP_Port ipp, const uint8_t *public_key, uint64_t ping_id,
uint8_t *shared_encryption_key)
{
uint8_t pk[DHT_PING_SIZE];
int rc;
if (id_equal(public_key, ping->dht->self_public_key))
return 1;
uint8_t ping_plain[PING_PLAIN_SIZE];
ping_plain[0] = NET_PACKET_PING_RESPONSE;
memcpy(ping_plain + 1, &ping_id, sizeof(ping_id));
pk[0] = NET_PACKET_PING_RESPONSE;
id_copy(pk + 1, ping->dht->self_public_key); // Our pubkey
new_nonce(pk + 1 + crypto_box_PUBLICKEYBYTES); // Generate new nonce
// Encrypt ping_id using recipient privkey
rc = encrypt_data_symmetric(shared_encryption_key,
pk + 1 + crypto_box_PUBLICKEYBYTES,
ping_plain, sizeof(ping_plain),
pk + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES );
if (rc != PING_PLAIN_SIZE + crypto_box_MACBYTES)
return 1;
return sendpacket(ping->dht->net, ipp, pk, sizeof(pk));
}
static int handle_ping_request(void *_dht, IP_Port source, const uint8_t *packet, uint16_t length)
{
DHT *dht = _dht;
int rc;
if (length != DHT_PING_SIZE)
return 1;
PING *ping = dht->ping;
if (id_equal(packet + 1, ping->dht->self_public_key))
return 1;
uint8_t shared_key[crypto_box_BEFORENMBYTES];
uint8_t ping_plain[PING_PLAIN_SIZE];
// Decrypt ping_id
DHT_get_shared_key_recv(dht, shared_key, packet + 1);
rc = decrypt_data_symmetric(shared_key,
packet + 1 + crypto_box_PUBLICKEYBYTES,
packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES,
PING_PLAIN_SIZE + crypto_box_MACBYTES,
ping_plain );
if (rc != sizeof(ping_plain))
return 1;
if (ping_plain[0] != NET_PACKET_PING_REQUEST)
return 1;
uint64_t ping_id;
memcpy(&ping_id, ping_plain + 1, sizeof(ping_id));
// Send response
send_ping_response(ping, source, packet + 1, ping_id, shared_key);
add_to_ping(ping, packet + 1, source);
return 0;
}
static int handle_ping_response(void *_dht, IP_Port source, const uint8_t *packet, uint16_t length)
{
DHT *dht = _dht;
int rc;
if (length != DHT_PING_SIZE)
return 1;
PING *ping = dht->ping;
if (id_equal(packet + 1, ping->dht->self_public_key))
return 1;
uint8_t shared_key[crypto_box_BEFORENMBYTES];
// generate key to encrypt ping_id with recipient privkey
DHT_get_shared_key_sent(ping->dht, shared_key, packet + 1);
uint8_t ping_plain[PING_PLAIN_SIZE];
// Decrypt ping_id
rc = decrypt_data_symmetric(shared_key,
packet + 1 + crypto_box_PUBLICKEYBYTES,
packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES,
PING_PLAIN_SIZE + crypto_box_MACBYTES,
ping_plain);
if (rc != sizeof(ping_plain))
return 1;
if (ping_plain[0] != NET_PACKET_PING_RESPONSE)
return 1;
uint64_t ping_id;
memcpy(&ping_id, ping_plain + 1, sizeof(ping_id));
uint8_t data[PING_DATA_SIZE];
if (ping_array_check(data, sizeof(data), &ping->ping_array, ping_id) != sizeof(data))
return 1;
if (!id_equal(packet + 1, data))
return 1;
IP_Port ipp;
memcpy(&ipp, data + crypto_box_PUBLICKEYBYTES, sizeof(IP_Port));
if (!ipport_equal(&ipp, &source))
return 1;
addto_lists(dht, source, packet + 1);
return 0;
}
/* Check if public_key with ip_port is in the list.
*
* return 1 if it is.
* return 0 if it isn't.
*/
static int in_list(const Client_data *list, uint16_t length, const uint8_t *public_key, IP_Port ip_port)
{
unsigned int i;
for (i = 0; i < length; ++i) {
if (id_equal(list[i].public_key, public_key)) {
const IPPTsPng *ipptp;
if (ip_port.ip.family == AF_INET) {
ipptp = &list[i].assoc4;
} else {
ipptp = &list[i].assoc6;
}
if (!is_timeout(ipptp->timestamp, BAD_NODE_TIMEOUT) && ipport_equal(&ipptp->ip_port, &ip_port))
return 1;
}
}
return 0;
}
/* Add nodes to the to_ping list.
* All nodes in this list are pinged every TIME_TO_PING seconds
* and are then removed from the list.
* If the list is full the nodes farthest from our public_key are replaced.
* The purpose of this list is to enable quick integration of new nodes into the
* network while preventing amplification attacks.
*
* return 0 if node was added.
* return -1 if node was not added.
*/
int add_to_ping(PING *ping, const uint8_t *public_key, IP_Port ip_port)
{
if (!ip_isset(&ip_port.ip))
return -1;
if (in_list(ping->dht->close_clientlist, LCLIENT_LIST, public_key, ip_port))
return -1;
IP_Port temp;
if (DHT_getfriendip(ping->dht, public_key, &temp) == 0) {
send_ping_request(ping, ip_port, public_key);
return -1;
}
unsigned int i;
for (i = 0; i < MAX_TO_PING; ++i) {
if (!ip_isset(&ping->to_ping[i].ip_port.ip)) {
memcpy(ping->to_ping[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
ipport_copy(&ping->to_ping[i].ip_port, &ip_port);
return 0;
}
if (memcmp(ping->to_ping[i].public_key, public_key, crypto_box_PUBLICKEYBYTES) == 0) {
return -1;
}
}
unsigned int r = rand();
for (i = 0; i < MAX_TO_PING; ++i) {
if (id_closest(ping->dht->self_public_key, ping->to_ping[(i + r) % MAX_TO_PING].public_key, public_key) == 2) {
memcpy(ping->to_ping[(i + r) % MAX_TO_PING].public_key, public_key, crypto_box_PUBLICKEYBYTES);
ipport_copy(&ping->to_ping[(i + r) % MAX_TO_PING].ip_port, &ip_port);
return 0;
}
}
return -1;
}
/* Ping all the valid nodes in the to_ping list every TIME_TO_PING seconds.
* This function must be run at least once every TIME_TO_PING seconds.
*/
void do_to_ping(PING *ping)
{
if (!is_timeout(ping->last_to_ping, TIME_TO_PING))
return;
if (!ip_isset(&ping->to_ping[0].ip_port.ip))
return;
unsigned int i;
for (i = 0; i < MAX_TO_PING; ++i) {
if (!ip_isset(&ping->to_ping[i].ip_port.ip))
break;
send_ping_request(ping, ping->to_ping[i].ip_port, ping->to_ping[i].public_key);
ip_reset(&ping->to_ping[i].ip_port.ip);
}
if (i != 0)
ping->last_to_ping = unix_time();
}
PING *new_ping(DHT *dht)
{
PING *ping = calloc(1, sizeof(PING));
if (ping == NULL)
return NULL;
if (ping_array_init(&ping->ping_array, PING_NUM_MAX, PING_TIMEOUT) != 0) {
free(ping);
return NULL;
}
ping->dht = dht;
networking_registerhandler(ping->dht->net, NET_PACKET_PING_REQUEST, &handle_ping_request, dht);
networking_registerhandler(ping->dht->net, NET_PACKET_PING_RESPONSE, &handle_ping_response, dht);
return ping;
}
void kill_ping(PING *ping)
{
networking_registerhandler(ping->dht->net, NET_PACKET_PING_REQUEST, NULL, NULL);
networking_registerhandler(ping->dht->net, NET_PACKET_PING_RESPONSE, NULL, NULL);
ping_array_free_all(&ping->ping_array);
free(ping);
}
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