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/*
* ping.c -- Buffered pinging using cyclic arrays.
*
* This file is donated to the Tox Project.
* Copyright 2013 plutooo
*/
#include <stdbool.h>
#include <stdint.h>
#include "DHT.h"
#include "net_crypto.h"
#include "packets.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;
static pinged_t pings[PING_NUM_MAX];
static size_t num_pings;
static size_t pos_pings;
static clientid_t* self_id = (clientid_t*) &self_public_key;
extern uint8_t self_secret_key[crypto_box_SECRETKEYBYTES]; // DHT.c
void init_ping()
{
num_pings = 0;
pos_pings = 0;
}
static bool is_timeout(uint64_t time)
{
return (time + PING_TIMEOUT) < now();
}
static void remove_timeouts() // O(n)
{
size_t i, id;
size_t new_pos = pos_pings;
size_t new_num = num_pings;
// Loop through buffer, oldest first
for (i=0; i<num_pings; i++) {
id = (pos_pings + i) % PING_NUM_MAX;
if(is_timeout(pings[id].timestamp)) {
new_pos++;
new_num--;
}
// Break here because list is sorted.
else {
break;
}
}
num_pings = new_num;
pos_pings = new_pos % PING_NUM_MAX;
}
uint64_t add_ping(IP_Port ipp) // O(n)
{
size_t p;
remove_timeouts();
// Remove oldest ping if full buffer
if (num_pings == PING_NUM_MAX) {
num_pings--;
pos_pings = (pos_pings + 1) % PING_NUM_MAX;
}
// Insert new ping at end of list
p = (pos_pings + num_pings) % PING_NUM_MAX;
pings[p].ipp = ipp;
pings[p].timestamp = now();
pings[p].id = random_64b();
num_pings++;
return pings[p].id;
}
bool is_pinging(IP_Port ipp, uint64_t ping_id) // O(n) TODO: replace this with something else.
{
if (ipp.ip.i == 0 && ping_id == 0)
return false;
size_t i, id;
remove_timeouts();
for (i=0; i<num_pings; i++) {
id = (pos_pings + i) % PING_NUM_MAX;
// ping_id = 0 means match any id
if ((ipp_eq(pings[id].ipp, ipp) || ipp.ip.i == 0) && (pings[id].id == ping_id || ping_id == 0)) {
return true;
}
}
return false;
}
int send_ping_request(IP_Port ipp, clientid_t* client_id)
{
pingreq_t pk;
int rc;
uint64_t ping_id;
if (is_pinging(ipp, 0) || id_eq(client_id, self_id))
return 1;
// Generate random ping_id
ping_id = add_ping(ipp);
pk.magic = PACKET_PING_REQ;
id_cpy(&pk.client_id, self_id); // Our pubkey
random_nonce((uint8_t*) &pk.nonce); // Generate random nonce
// Encrypt ping_id using recipient privkey
rc = encrypt_data((uint8_t*) client_id,
self_secret_key,
(uint8_t*) &pk.nonce,
(uint8_t*) &ping_id, sizeof(ping_id),
(uint8_t*) &pk.ping_id);
if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
return sendpacket(ipp, (uint8_t*) &pk, sizeof(pk));
}
int send_ping_response(IP_Port ipp, clientid_t* client_id, uint64_t ping_id)
{
pingres_t pk;
int rc;
if (id_eq(client_id, self_id))
return 1;
pk.magic = PACKET_PING_RES;
id_cpy(&pk.client_id, self_id); // Our pubkey
random_nonce((uint8_t*) &pk.nonce); // Generate random nonce
// Encrypt ping_id using recipient privkey
rc = encrypt_data((uint8_t*) client_id,
self_secret_key,
(uint8_t*) &pk.nonce,
(uint8_t*) &ping_id, sizeof(ping_id),
(uint8_t*) &pk.ping_id);
if (rc != sizeof(ping_id) + ENCRYPTION_PADDING)
return 1;
return sendpacket(ipp, (uint8_t*) &pk, sizeof(pk));
}
int handle_ping_request(IP_Port source, uint8_t* packet, uint32_t length)
{
pingreq_t* p = (pingreq_t*) packet;
int rc;
uint64_t ping_id;
if (length != sizeof(pingreq_t) || id_eq(&p->client_id, self_id))
return 1;
// Decrypt ping_id
rc = decrypt_data((uint8_t*) &p->client_id,
self_secret_key,
(uint8_t*) &p->nonce,
(uint8_t*) &p->ping_id,
sizeof(ping_id) + ENCRYPTION_PADDING,
(uint8_t*) &ping_id);
if (rc != sizeof(ping_id))
return 1;
// Send response
send_ping_response(source, &p->client_id, ping_id);
send_ping_request(source, &p->client_id); // Make this smarter?
return 0;
}
int handle_ping_response(IP_Port source, uint8_t* packet, uint32_t length)
{
pingres_t* p = (pingres_t*) packet;
int rc;
uint64_t ping_id;
if (length != sizeof(pingres_t) || id_eq(&p->client_id, self_id))
return 1;
// Decrypt ping_id
rc = decrypt_data((uint8_t*) &p->client_id,
self_secret_key,
(uint8_t*) &p->nonce,
(uint8_t*) &p->ping_id,
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(source, ping_id))
return 1;
// Associate source ip with client_id
addto_lists(source, (uint8_t*) &p->client_id);
return 0;
}
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