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/*
* ping.c -- Buffered pinging using cyclic arrays.
*
* This file is donated to the Tox Project.
* Copyright 2013 plutooo
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdbool.h>
#include <stdint.h>
#include "DHT.h"
#include "net_crypto.h"
#include "network.h"
#include "util.h"
#define PING_NUM_MAX 256
#define PING_TIMEOUT 5 // 5s
typedef struct {
IP_Port ipp;
uint64_t id;
uint64_t timestamp;
} pinged_t;
typedef struct {
pinged_t pings[PING_NUM_MAX];
size_t num_pings;
size_t pos_pings;
} PING;
void *new_ping(void)
{
return calloc(1, sizeof(PING));
}
void kill_ping(void *ping)
{
free(ping);
}
static bool is_timeout(uint64_t time)
{
return (time + PING_TIMEOUT) < now();
}
static void remove_timeouts(void *ping) // O(n)
{
PING *png = ping;
size_t i, id;
size_t new_pos = png->pos_pings;
size_t new_num = png->num_pings;
// Loop through buffer, oldest first.
for (i = 0; i < png->num_pings; i++) {
id = (png->pos_pings + i) % PING_NUM_MAX;
if (is_timeout(png->pings[id].timestamp)) {
new_pos++;
new_num--;
}
// Break here because list is sorted.
else {
break;
}
}
png->num_pings = new_num;
png->pos_pings = new_pos % PING_NUM_MAX;
}
uint64_t add_ping(void *ping, IP_Port ipp) // O(n)
{
PING *png = ping;
size_t p;
remove_timeouts(ping);
/* Remove oldest ping if full buffer. */
if (png->num_pings == PING_NUM_MAX) {
png->num_pings--;
png->pos_pings = (png->pos_pings + 1) % PING_NUM_MAX;
}
/* Insert new ping at end of list. */
p = (png->pos_pings + png->num_pings) % PING_NUM_MAX;
png->pings[p].ipp = ipp;
png->pings[p].timestamp = now();
png->pings[p].id = random_64b();
png->num_pings++;
return png->pings[p].id;
}
bool is_pinging(void *ping, IP_Port ipp, uint64_t ping_id) // O(n) TODO: Replace this with something else.
{
PING *png = ping;
/* shouldn't that be an OR ? */
if (!ip_isset(&ipp.ip) && ping_id == 0)
return false;
size_t i, id;
remove_timeouts(ping);
for (i = 0; i < png->num_pings; i++) {
id = (png->pos_pings + i) % PING_NUM_MAX;
/* ping_id = 0 means match any id. */
if ((!ip_isset(&ipp.ip) || ipport_equal(&png->pings[id].ipp, &ipp)) &&
(png->pings[id].id == ping_id || ping_id == 0)) {
return true;
}
}
return false;
}
#define DHT_PING_SIZE (1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES + sizeof(uint64_t) + ENCRYPTION_PADDING)
int send_ping_request(void *ping, Net_Crypto *c, IP_Port ipp, uint8_t *client_id)
{
uint8_t pk[DHT_PING_SIZE];
int rc;
uint64_t ping_id;
if (is_pinging(ping, ipp, 0) || id_eq(client_id, c->self_public_key))
return 1;
// Generate random ping_id.
ping_id = add_ping(ping, ipp);
pk[0] = NET_PACKET_PING_REQUEST;
id_cpy(pk + 1, c->self_public_key); // Our pubkey
random_nonce(pk + 1 + CLIENT_ID_SIZE); // Generate random nonce
// Encrypt ping_id using recipient privkey
rc = encrypt_data(client_id,
c->self_secret_key,
pk + 1 + CLIENT_ID_SIZE,
(uint8_t *) &ping_id, sizeof(ping_id),
pk + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES);
if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
return sendpacket(c->lossless_udp->net, ipp, pk, sizeof(pk));
}
int send_ping_response(Net_Crypto *c, IP_Port ipp, uint8_t *client_id, uint64_t ping_id)
{
uint8_t pk[DHT_PING_SIZE];
int rc;
if (id_eq(client_id, c->self_public_key))
return 1;
pk[0] = NET_PACKET_PING_RESPONSE;
id_cpy(pk + 1, c->self_public_key); // Our pubkey
random_nonce(pk + 1 + CLIENT_ID_SIZE); // Generate random nonce
// Encrypt ping_id using recipient privkey
rc = encrypt_data(client_id,
c->self_secret_key,
pk + 1 + CLIENT_ID_SIZE,
(uint8_t *) &ping_id, sizeof(ping_id),
pk + 1 + CLIENT_ID_SIZE + crypto_box_NONCEBYTES);
if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
return sendpacket(c->lossless_udp->net, ipp, pk, sizeof(pk));
}
int handle_ping_request(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
int rc;
uint64_t ping_id;
if (length != DHT_PING_SIZE)
return 1;
if (id_eq(packet + 1, dht->c->self_public_key))
return 1;
// Decrypt ping_id
rc = decrypt_data(packet + 1,
dht->c->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 (rc != sizeof(ping_id))
return 1;
// Send response
send_ping_response(dht->c, source, packet + 1, ping_id);
add_toping(dht, packet + 1, source);
return 0;
}
int handle_ping_response(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
int rc;
uint64_t ping_id;
if (length != DHT_PING_SIZE)
return 1;
if (id_eq(packet + 1, dht->c->self_public_key))
return 1;
// Decrypt ping_id
rc = decrypt_data(packet + 1,
dht->c->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 (rc != sizeof(ping_id))
return 1;
/* Make sure ping_id is correct. */
if (!is_pinging(dht->ping, source, ping_id))
return 1;
// Associate source ip with client_id
addto_lists(dht, source, packet + 1);
return 0;
}
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