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tomato-testing/toxcore/TCP_server.c
Green Sky 227425b90e Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69 
git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
2023-07-25 11:53:09 +02:00

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/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2016-2018 The TokTok team.
* Copyright © 2014 Tox project.
*/
/**
* Implementation of the TCP relay server part of Tox.
*/
#include "TCP_server.h"
#include <stdlib.h>
#include <string.h>
#if !defined(_WIN32) && !defined(__WIN32__) && !defined (WIN32)
#include <sys/ioctl.h>
#endif
#ifdef TCP_SERVER_USE_EPOLL
#include <sys/epoll.h>
#include <unistd.h>
#endif
#include "TCP_common.h"
#include "ccompat.h"
#include "list.h"
#include "mono_time.h"
#include "util.h"
#ifdef TCP_SERVER_USE_EPOLL
#define TCP_SOCKET_LISTENING 0
#define TCP_SOCKET_INCOMING 1
#define TCP_SOCKET_UNCONFIRMED 2
#define TCP_SOCKET_CONFIRMED 3
#endif
typedef struct TCP_Secure_Conn {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint32_t index;
// TODO(iphydf): Add an enum for this (same as in TCP_client.c, probably).
uint8_t status; /* 0 if not used, 1 if other is offline, 2 if other is online. */
uint8_t other_id;
} TCP_Secure_Conn;
typedef struct TCP_Secure_Connection {
TCP_Connection con;
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint8_t recv_nonce[CRYPTO_NONCE_SIZE]; /* Nonce of received packets. */
uint16_t next_packet_length;
TCP_Secure_Conn connections[NUM_CLIENT_CONNECTIONS];
uint8_t status;
uint64_t identifier;
uint64_t last_pinged;
uint64_t ping_id;
} TCP_Secure_Connection;
struct TCP_Server {
const Logger *logger;
const Random *rng;
const Network *ns;
Onion *onion;
Forwarding *forwarding;
#ifdef TCP_SERVER_USE_EPOLL
int efd;
uint64_t last_run_pinged;
#endif
Socket *socks_listening;
unsigned int num_listening_socks;
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint8_t secret_key[CRYPTO_SECRET_KEY_SIZE];
TCP_Secure_Connection incoming_connection_queue[MAX_INCOMING_CONNECTIONS];
uint16_t incoming_connection_queue_index;
TCP_Secure_Connection unconfirmed_connection_queue[MAX_INCOMING_CONNECTIONS];
uint16_t unconfirmed_connection_queue_index;
TCP_Secure_Connection *accepted_connection_array;
uint32_t size_accepted_connections;
uint32_t num_accepted_connections;
uint64_t counter;
BS_List accepted_key_list;
};
const uint8_t *tcp_server_public_key(const TCP_Server *tcp_server)
{
return tcp_server->public_key;
}
size_t tcp_server_listen_count(const TCP_Server *tcp_server)
{
return tcp_server->num_listening_socks;
}
/** This is needed to compile on Android below API 21 */
#ifdef TCP_SERVER_USE_EPOLL
#ifndef EPOLLRDHUP
#define EPOLLRDHUP 0x2000
#endif
#endif
/** @brief Increase the size of the connection list
*
* @retval -1 on failure
* @retval 0 on success.
*/
non_null()
static int alloc_new_connections(TCP_Server *tcp_server, uint32_t num)
{
const uint32_t new_size = tcp_server->size_accepted_connections + num;
if (new_size < tcp_server->size_accepted_connections) {
return -1;
}
TCP_Secure_Connection *new_connections = (TCP_Secure_Connection *)realloc(
tcp_server->accepted_connection_array,
new_size * sizeof(TCP_Secure_Connection));
if (new_connections == nullptr) {
return -1;
}
const uint32_t old_size = tcp_server->size_accepted_connections;
const uint32_t size_new_entries = num * sizeof(TCP_Secure_Connection);
memset(new_connections + old_size, 0, size_new_entries);
tcp_server->accepted_connection_array = new_connections;
tcp_server->size_accepted_connections = new_size;
return 0;
}
non_null()
static void wipe_secure_connection(TCP_Secure_Connection *con)
{
if (con->status != 0) {
wipe_priority_list(con->con.priority_queue_start);
crypto_memzero(con, sizeof(TCP_Secure_Connection));
}
}
non_null()
static void move_secure_connection(TCP_Secure_Connection *con_new, TCP_Secure_Connection *con_old)
{
*con_new = *con_old;
crypto_memzero(con_old, sizeof(TCP_Secure_Connection));
}
non_null()
static void free_accepted_connection_array(TCP_Server *tcp_server)
{
if (tcp_server->accepted_connection_array == nullptr) {
return;
}
for (uint32_t i = 0; i < tcp_server->size_accepted_connections; ++i) {
wipe_secure_connection(&tcp_server->accepted_connection_array[i]);
}
free(tcp_server->accepted_connection_array);
tcp_server->accepted_connection_array = nullptr;
tcp_server->size_accepted_connections = 0;
}
/**
* @return index corresponding to connection with peer on success
* @retval -1 on failure.
*/
non_null()
static int get_TCP_connection_index(const TCP_Server *tcp_server, const uint8_t *public_key)
{
return bs_list_find(&tcp_server->accepted_key_list, public_key);
}
non_null()
static int kill_accepted(TCP_Server *tcp_server, int index);
/** @brief Add accepted TCP connection to the list.
*
* @return index on success
* @retval -1 on failure
*/
non_null()
static int add_accepted(TCP_Server *tcp_server, const Mono_Time *mono_time, TCP_Secure_Connection *con)
{
int index = get_TCP_connection_index(tcp_server, con->public_key);
if (index != -1) { /* If an old connection to the same public key exists, kill it. */
kill_accepted(tcp_server, index);
index = -1;
}
if (tcp_server->size_accepted_connections == tcp_server->num_accepted_connections) {
if (alloc_new_connections(tcp_server, 4) == -1) {
return -1;
}
index = tcp_server->num_accepted_connections;
} else {
for (uint32_t i = tcp_server->size_accepted_connections; i != 0; --i) {
if (tcp_server->accepted_connection_array[i - 1].status == TCP_STATUS_NO_STATUS) {
index = i - 1;
break;
}
}
}
if (index == -1) {
LOGGER_ERROR(tcp_server->logger, "FAIL index is -1");
return -1;
}
if (!bs_list_add(&tcp_server->accepted_key_list, con->public_key, index)) {
return -1;
}
move_secure_connection(&tcp_server->accepted_connection_array[index], con);
tcp_server->accepted_connection_array[index].status = TCP_STATUS_CONFIRMED;
++tcp_server->num_accepted_connections;
tcp_server->accepted_connection_array[index].identifier = ++tcp_server->counter;
tcp_server->accepted_connection_array[index].last_pinged = mono_time_get(mono_time);
tcp_server->accepted_connection_array[index].ping_id = 0;
return index;
}
/** @brief Delete accepted connection from list.
*
* @retval 0 on success
* @retval -1 on failure
*/
non_null()
static int del_accepted(TCP_Server *tcp_server, int index)
{
if ((uint32_t)index >= tcp_server->size_accepted_connections) {
return -1;
}
if (tcp_server->accepted_connection_array[index].status == TCP_STATUS_NO_STATUS) {
return -1;
}
if (!bs_list_remove(&tcp_server->accepted_key_list, tcp_server->accepted_connection_array[index].public_key, index)) {
return -1;
}
wipe_secure_connection(&tcp_server->accepted_connection_array[index]);
--tcp_server->num_accepted_connections;
if (tcp_server->num_accepted_connections == 0) {
free_accepted_connection_array(tcp_server);
}
return 0;
}
/** Kill a TCP_Secure_Connection */
non_null()
static void kill_TCP_secure_connection(TCP_Secure_Connection *con)
{
kill_sock(con->con.ns, con->con.sock);
wipe_secure_connection(con);
}
non_null()
static int rm_connection_index(TCP_Server *tcp_server, TCP_Secure_Connection *con, uint8_t con_number);
/** @brief Kill an accepted TCP_Secure_Connection
*
* return -1 on failure.
* return 0 on success.
*/
static int kill_accepted(TCP_Server *tcp_server, int index)
{
if ((uint32_t)index >= tcp_server->size_accepted_connections) {
return -1;
}
for (uint32_t i = 0; i < NUM_CLIENT_CONNECTIONS; ++i) {
rm_connection_index(tcp_server, &tcp_server->accepted_connection_array[index], i);
}
const Socket sock = tcp_server->accepted_connection_array[index].con.sock;
if (del_accepted(tcp_server, index) != 0) {
return -1;
}
kill_sock(tcp_server->ns, sock);
return 0;
}
/**
* @retval 1 if everything went well.
* @retval -1 if the connection must be killed.
*/
non_null()
static int handle_TCP_handshake(const Logger *logger, TCP_Secure_Connection *con, const uint8_t *data, uint16_t length,
const uint8_t *self_secret_key)
{
if (length != TCP_CLIENT_HANDSHAKE_SIZE) {
LOGGER_ERROR(logger, "invalid handshake length: %d != %d", length, TCP_CLIENT_HANDSHAKE_SIZE);
return -1;
}
if (con->status != TCP_STATUS_CONNECTED) {
LOGGER_ERROR(logger, "TCP connection %u not connected", (unsigned int)con->identifier);
return -1;
}
uint8_t shared_key[CRYPTO_SHARED_KEY_SIZE];
encrypt_precompute(data, self_secret_key, shared_key);
uint8_t plain[TCP_HANDSHAKE_PLAIN_SIZE];
int len = decrypt_data_symmetric(shared_key, data + CRYPTO_PUBLIC_KEY_SIZE,
data + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_NONCE_SIZE, TCP_HANDSHAKE_PLAIN_SIZE + CRYPTO_MAC_SIZE, plain);
if (len != TCP_HANDSHAKE_PLAIN_SIZE) {
LOGGER_ERROR(logger, "invalid TCP handshake decrypted length: %d != %d", len, TCP_HANDSHAKE_PLAIN_SIZE);
crypto_memzero(shared_key, sizeof(shared_key));
return -1;
}
memcpy(con->public_key, data, CRYPTO_PUBLIC_KEY_SIZE);
uint8_t temp_secret_key[CRYPTO_SECRET_KEY_SIZE];
uint8_t resp_plain[TCP_HANDSHAKE_PLAIN_SIZE];
crypto_new_keypair(con->con.rng, resp_plain, temp_secret_key);
random_nonce(con->con.rng, con->con.sent_nonce);
memcpy(resp_plain + CRYPTO_PUBLIC_KEY_SIZE, con->con.sent_nonce, CRYPTO_NONCE_SIZE);
memcpy(con->recv_nonce, plain + CRYPTO_PUBLIC_KEY_SIZE, CRYPTO_NONCE_SIZE);
uint8_t response[TCP_SERVER_HANDSHAKE_SIZE];
random_nonce(con->con.rng, response);
len = encrypt_data_symmetric(shared_key, response, resp_plain, TCP_HANDSHAKE_PLAIN_SIZE,
response + CRYPTO_NONCE_SIZE);
if (len != TCP_HANDSHAKE_PLAIN_SIZE + CRYPTO_MAC_SIZE) {
crypto_memzero(shared_key, sizeof(shared_key));
return -1;
}
IP_Port ipp = {{{0}}};
if (TCP_SERVER_HANDSHAKE_SIZE != net_send(con->con.ns, logger, con->con.sock, response, TCP_SERVER_HANDSHAKE_SIZE, &ipp)) {
crypto_memzero(shared_key, sizeof(shared_key));
return -1;
}
encrypt_precompute(plain, temp_secret_key, con->con.shared_key);
con->status = TCP_STATUS_UNCONFIRMED;
crypto_memzero(shared_key, sizeof(shared_key));
return 1;
}
/**
* @retval 1 if connection handshake was handled correctly.
* @retval 0 if we didn't get it yet.
* @retval -1 if the connection must be killed.
*/
non_null()
static int read_connection_handshake(const Logger *logger, TCP_Secure_Connection *con, const uint8_t *self_secret_key)
{
uint8_t data[TCP_CLIENT_HANDSHAKE_SIZE];
const int len = read_TCP_packet(logger, con->con.ns, con->con.sock, data, TCP_CLIENT_HANDSHAKE_SIZE, &con->con.ip_port);
if (len == -1) {
LOGGER_TRACE(logger, "connection handshake is not ready yet");
return 0;
}
return handle_TCP_handshake(logger, con, data, len, self_secret_key);
}
/**
* @retval 1 on success.
* @retval 0 if could not send packet.
* @retval -1 on failure (connection must be killed).
*/
non_null()
static int send_routing_response(const Logger *logger, TCP_Secure_Connection *con, uint8_t rpid,
const uint8_t *public_key)
{
uint8_t data[2 + CRYPTO_PUBLIC_KEY_SIZE];
data[0] = TCP_PACKET_ROUTING_RESPONSE;
data[1] = rpid;
memcpy(data + 2, public_key, CRYPTO_PUBLIC_KEY_SIZE);
return write_packet_TCP_secure_connection(logger, &con->con, data, sizeof(data), true);
}
/**
* @retval 1 on success.
* @retval 0 if could not send packet.
* @retval -1 on failure (connection must be killed).
*/
non_null()
static int send_connect_notification(const Logger *logger, TCP_Secure_Connection *con, uint8_t id)
{
uint8_t data[2] = {TCP_PACKET_CONNECTION_NOTIFICATION, (uint8_t)(id + NUM_RESERVED_PORTS)};
return write_packet_TCP_secure_connection(logger, &con->con, data, sizeof(data), true);
}
/**
* @retval 1 on success.
* @retval 0 if could not send packet.
* @retval -1 on failure (connection must be killed).
*/
non_null()
static int send_disconnect_notification(const Logger *logger, TCP_Secure_Connection *con, uint8_t id)
{
uint8_t data[2] = {TCP_PACKET_DISCONNECT_NOTIFICATION, (uint8_t)(id + NUM_RESERVED_PORTS)};
return write_packet_TCP_secure_connection(logger, &con->con, data, sizeof(data), true);
}
/**
* @retval 0 on success.
* @retval -1 on failure (connection must be killed).
*/
non_null()
static int handle_TCP_routing_req(TCP_Server *tcp_server, uint32_t con_id, const uint8_t *public_key)
{
uint32_t index = -1;
TCP_Secure_Connection *con = &tcp_server->accepted_connection_array[con_id];
/* If person tries to cennect to himself we deny the request*/
if (pk_equal(con->public_key, public_key)) {
if (send_routing_response(tcp_server->logger, con, 0, public_key) == -1) {
return -1;
}
return 0;
}
for (uint32_t i = 0; i < NUM_CLIENT_CONNECTIONS; ++i) {
if (con->connections[i].status != 0) {
if (pk_equal(public_key, con->connections[i].public_key)) {
if (send_routing_response(tcp_server->logger, con, i + NUM_RESERVED_PORTS, public_key) == -1) {
return -1;
}
return 0;
}
} else if (index == (uint32_t) -1) {
index = i;
}
}
if (index == (uint32_t) -1) {
if (send_routing_response(tcp_server->logger, con, 0, public_key) == -1) {
return -1;
}
return 0;
}
const int ret = send_routing_response(tcp_server->logger, con, index + NUM_RESERVED_PORTS, public_key);
if (ret == 0) {
return 0;
}
if (ret == -1) {
return -1;
}
con->connections[index].status = 1;
memcpy(con->connections[index].public_key, public_key, CRYPTO_PUBLIC_KEY_SIZE);
const int other_index = get_TCP_connection_index(tcp_server, public_key);
if (other_index != -1) {
uint32_t other_id = -1;
TCP_Secure_Connection *other_conn = &tcp_server->accepted_connection_array[other_index];
for (uint32_t i = 0; i < NUM_CLIENT_CONNECTIONS; ++i) {
if (other_conn->connections[i].status == 1
&& pk_equal(other_conn->connections[i].public_key, con->public_key)) {
other_id = i;
break;
}
}
if (other_id != (uint32_t) -1) {
con->connections[index].status = 2;
con->connections[index].index = other_index;
con->connections[index].other_id = other_id;
other_conn->connections[other_id].status = 2;
other_conn->connections[other_id].index = con_id;
other_conn->connections[other_id].other_id = index;
// TODO(irungentoo): return values?
send_connect_notification(tcp_server->logger, con, index);
send_connect_notification(tcp_server->logger, other_conn, other_id);
}
}
return 0;
}
/**
* @retval 0 on success.
* @retval -1 on failure (connection must be killed).
*/
non_null()
static int handle_TCP_oob_send(TCP_Server *tcp_server, uint32_t con_id, const uint8_t *public_key, const uint8_t *data,
uint16_t length)
{
if (length == 0 || length > TCP_MAX_OOB_DATA_LENGTH) {
return -1;
}
const TCP_Secure_Connection *con = &tcp_server->accepted_connection_array[con_id];
const int other_index = get_TCP_connection_index(tcp_server, public_key);
if (other_index != -1) {
VLA(uint8_t, resp_packet, 1 + CRYPTO_PUBLIC_KEY_SIZE + length);
resp_packet[0] = TCP_PACKET_OOB_RECV;
memcpy(resp_packet + 1, con->public_key, CRYPTO_PUBLIC_KEY_SIZE);
memcpy(resp_packet + 1 + CRYPTO_PUBLIC_KEY_SIZE, data, length);
write_packet_TCP_secure_connection(tcp_server->logger, &tcp_server->accepted_connection_array[other_index].con,
resp_packet, SIZEOF_VLA(resp_packet), false);
}
return 0;
}
/** @brief Remove connection with con_number from the connections array of con.
*
* return -1 on failure.
* return 0 on success.
*/
static int rm_connection_index(TCP_Server *tcp_server, TCP_Secure_Connection *con, uint8_t con_number)
{
if (con_number >= NUM_CLIENT_CONNECTIONS) {
return -1;
}
if (con->connections[con_number].status != 0) {
if (con->connections[con_number].status == 2) {
const uint32_t index = con->connections[con_number].index;
const uint8_t other_id = con->connections[con_number].other_id;
if (index >= tcp_server->size_accepted_connections) {
return -1;
}
tcp_server->accepted_connection_array[index].connections[other_id].other_id = 0;
tcp_server->accepted_connection_array[index].connections[other_id].index = 0;
tcp_server->accepted_connection_array[index].connections[other_id].status = 1;
// TODO(irungentoo): return values?
send_disconnect_notification(tcp_server->logger, &tcp_server->accepted_connection_array[index], other_id);
}
con->connections[con_number].index = 0;
con->connections[con_number].other_id = 0;
con->connections[con_number].status = 0;
return 0;
}
return -1;
}
/** @brief Encode con_id and identifier as a custom IP_Port.
*
* @return ip_port.
*/
static IP_Port con_id_to_ip_port(uint32_t con_id, uint64_t identifier)
{
IP_Port ip_port = {{{0}}};
ip_port.ip.family = net_family_tcp_client();
ip_port.ip.ip.v6.uint32[0] = con_id;
ip_port.ip.ip.v6.uint64[1] = identifier;
return ip_port;
}
/** @brief Decode ip_port created by con_id_to_ip_port to con_id.
*
* @retval true on success.
* @retval false if ip_port is invalid.
*/
non_null()
static bool ip_port_to_con_id(const TCP_Server *tcp_server, const IP_Port *ip_port, uint32_t *con_id)
{
*con_id = ip_port->ip.ip.v6.uint32[0];
return net_family_is_tcp_client(ip_port->ip.family) &&
*con_id < tcp_server->size_accepted_connections &&
tcp_server->accepted_connection_array[*con_id].identifier == ip_port->ip.ip.v6.uint64[1];
}
non_null()
static int handle_onion_recv_1(void *object, const IP_Port *dest, const uint8_t *data, uint16_t length)
{
TCP_Server *tcp_server = (TCP_Server *)object;
uint32_t index;
if (!ip_port_to_con_id(tcp_server, dest, &index)) {
return 1;
}
TCP_Secure_Connection *con = &tcp_server->accepted_connection_array[index];
VLA(uint8_t, packet, 1 + length);
memcpy(packet + 1, data, length);
packet[0] = TCP_PACKET_ONION_RESPONSE;
if (write_packet_TCP_secure_connection(tcp_server->logger, &con->con, packet, SIZEOF_VLA(packet), false) != 1) {
return 1;
}
return 0;
}
non_null()
static bool handle_forward_reply_tcp(void *object, const uint8_t *sendback_data, uint16_t sendback_data_len,
const uint8_t *data, uint16_t length)
{
TCP_Server *tcp_server = (TCP_Server *)object;
if (sendback_data_len != 1 + sizeof(uint32_t) + sizeof(uint64_t)) {
return false;
}
if (*sendback_data != SENDBACK_TCP) {
return false;
}
uint32_t con_id;
uint64_t identifier;
net_unpack_u32(sendback_data + 1, &con_id);
net_unpack_u64(sendback_data + 1 + sizeof(uint32_t), &identifier);
if (con_id >= tcp_server->size_accepted_connections) {
return false;
}
TCP_Secure_Connection *con = &tcp_server->accepted_connection_array[con_id];
if (con->identifier != identifier) {
return false;
}
VLA(uint8_t, packet, 1 + length);
memcpy(packet + 1, data, length);
packet[0] = TCP_PACKET_FORWARDING;
return write_packet_TCP_secure_connection(tcp_server->logger, &con->con, packet, SIZEOF_VLA(packet), false) == 1;
}
/**
* @retval 0 on success
* @retval -1 on failure
*/
non_null()
static int handle_TCP_packet(TCP_Server *tcp_server, uint32_t con_id, const uint8_t *data, uint16_t length)
{
if (length == 0) {
return -1;
}
TCP_Secure_Connection *const con = &tcp_server->accepted_connection_array[con_id];
switch (data[0]) {
case TCP_PACKET_ROUTING_REQUEST: {
if (length != 1 + CRYPTO_PUBLIC_KEY_SIZE) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling routing request for %d", con_id);
return handle_TCP_routing_req(tcp_server, con_id, data + 1);
}
case TCP_PACKET_CONNECTION_NOTIFICATION: {
if (length != 2) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling connection notification for %d", con_id);
break;
}
case TCP_PACKET_DISCONNECT_NOTIFICATION: {
if (length != 2) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling disconnect notification for %d", con_id);
return rm_connection_index(tcp_server, con, data[1] - NUM_RESERVED_PORTS);
}
case TCP_PACKET_PING: {
if (length != 1 + sizeof(uint64_t)) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling ping for %d", con_id);
uint8_t response[1 + sizeof(uint64_t)];
response[0] = TCP_PACKET_PONG;
memcpy(response + 1, data + 1, sizeof(uint64_t));
write_packet_TCP_secure_connection(tcp_server->logger, &con->con, response, sizeof(response), true);
return 0;
}
case TCP_PACKET_PONG: {
if (length != 1 + sizeof(uint64_t)) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling pong for %d", con_id);
uint64_t ping_id;
memcpy(&ping_id, data + 1, sizeof(uint64_t));
if (ping_id != 0) {
if (ping_id == con->ping_id) {
con->ping_id = 0;
}
return 0;
}
return -1;
}
case TCP_PACKET_OOB_SEND: {
if (length <= 1 + CRYPTO_PUBLIC_KEY_SIZE) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling oob send for %d", con_id);
return handle_TCP_oob_send(tcp_server, con_id, data + 1, data + 1 + CRYPTO_PUBLIC_KEY_SIZE,
length - (1 + CRYPTO_PUBLIC_KEY_SIZE));
}
case TCP_PACKET_ONION_REQUEST: {
LOGGER_TRACE(tcp_server->logger, "handling onion request for %d", con_id);
if (tcp_server->onion != nullptr) {
if (length <= 1 + CRYPTO_NONCE_SIZE + ONION_SEND_BASE * 2) {
return -1;
}
IP_Port source = con_id_to_ip_port(con_id, con->identifier);
onion_send_1(tcp_server->onion, data + 1 + CRYPTO_NONCE_SIZE, length - (1 + CRYPTO_NONCE_SIZE), &source,
data + 1);
}
return 0;
}
case TCP_PACKET_ONION_RESPONSE: {
LOGGER_TRACE(tcp_server->logger, "handling onion response for %d", con_id);
return -1;
}
case TCP_PACKET_FORWARD_REQUEST: {
if (tcp_server->forwarding == nullptr) {
return -1;
}
const uint16_t sendback_data_len = 1 + sizeof(uint32_t) + sizeof(uint64_t);
uint8_t sendback_data[1 + sizeof(uint32_t) + sizeof(uint64_t)];
sendback_data[0] = SENDBACK_TCP;
net_pack_u32(sendback_data + 1, con_id);
net_pack_u64(sendback_data + 1 + sizeof(uint32_t), con->identifier);
IP_Port dest;
const int ipport_length = unpack_ip_port(&dest, data + 1, length - 1, false);
if (ipport_length == -1) {
return -1;
}
const uint8_t *const forward_data = data + (1 + ipport_length);
const uint16_t forward_data_len = length - (1 + ipport_length);
if (forward_data_len > MAX_FORWARD_DATA_SIZE) {
return -1;
}
send_forwarding(tcp_server->forwarding, &dest, sendback_data, sendback_data_len, forward_data, forward_data_len);
return 0;
}
case TCP_PACKET_FORWARDING: {
return -1;
}
default: {
if (data[0] < NUM_RESERVED_PORTS) {
return -1;
}
const uint8_t c_id = data[0] - NUM_RESERVED_PORTS;
LOGGER_TRACE(tcp_server->logger, "handling packet id %d for %d", c_id, con_id);
if (c_id >= NUM_CLIENT_CONNECTIONS) {
return -1;
}
if (con->connections[c_id].status == 0) {
return -1;
}
if (con->connections[c_id].status != 2) {
return 0;
}
const uint32_t index = con->connections[c_id].index;
const uint8_t other_c_id = con->connections[c_id].other_id + NUM_RESERVED_PORTS;
VLA(uint8_t, new_data, length);
memcpy(new_data, data, length);
new_data[0] = other_c_id;
const int ret = write_packet_TCP_secure_connection(tcp_server->logger,
&tcp_server->accepted_connection_array[index].con, new_data, length, false);
if (ret == -1) {
return -1;
}
return 0;
}
}
return 0;
}
non_null()
static int confirm_TCP_connection(TCP_Server *tcp_server, const Mono_Time *mono_time, TCP_Secure_Connection *con,
const uint8_t *data, uint16_t length)
{
const int index = add_accepted(tcp_server, mono_time, con);
if (index == -1) {
LOGGER_DEBUG(tcp_server->logger, "dropping connection %u: not accepted", (unsigned int)con->identifier);
kill_TCP_secure_connection(con);
return -1;
}
wipe_secure_connection(con);
if (handle_TCP_packet(tcp_server, index, data, length) == -1) {
LOGGER_DEBUG(tcp_server->logger, "dropping connection %u: data packet (len=%d) not handled",
(unsigned int)con->identifier, length);
kill_accepted(tcp_server, index);
return -1;
}
return index;
}
/**
* @return index on success
* @retval -1 on failure
*/
non_null()
static int accept_connection(TCP_Server *tcp_server, Socket sock)
{
if (!sock_valid(sock)) {
return -1;
}
if (!set_socket_nonblock(tcp_server->ns, sock)) {
kill_sock(tcp_server->ns, sock);
return -1;
}
if (!set_socket_nosigpipe(tcp_server->ns, sock)) {
kill_sock(tcp_server->ns, sock);
return -1;
}
const uint16_t index = tcp_server->incoming_connection_queue_index % MAX_INCOMING_CONNECTIONS;
TCP_Secure_Connection *conn = &tcp_server->incoming_connection_queue[index];
if (conn->status != TCP_STATUS_NO_STATUS) {
LOGGER_DEBUG(tcp_server->logger, "connection %d dropped before accepting", index);
kill_TCP_secure_connection(conn);
}
conn->status = TCP_STATUS_CONNECTED;
conn->con.ns = tcp_server->ns;
conn->con.rng = tcp_server->rng;
conn->con.sock = sock;
conn->next_packet_length = 0;
++tcp_server->incoming_connection_queue_index;
return index;
}
non_null()
static Socket new_listening_TCP_socket(const Logger *logger, const Network *ns, Family family, uint16_t port)
{
const Socket sock = net_socket(ns, family, TOX_SOCK_STREAM, TOX_PROTO_TCP);
if (!sock_valid(sock)) {
LOGGER_ERROR(logger, "TCP socket creation failed (family = %d)", family.value);
return net_invalid_socket;
}
bool ok = set_socket_nonblock(ns, sock);
if (ok && net_family_is_ipv6(family)) {
ok = set_socket_dualstack(ns, sock);
}
if (ok) {
ok = set_socket_reuseaddr(ns, sock);
}
ok = ok && bind_to_port(ns, sock, family, port) && (net_listen(ns, sock, TCP_MAX_BACKLOG) == 0);
if (!ok) {
char *const error = net_new_strerror(net_error());
LOGGER_WARNING(logger, "could not bind to TCP port %d (family = %d): %s",
port, family.value, error != nullptr ? error : "(null)");
net_kill_strerror(error);
kill_sock(ns, sock);
return net_invalid_socket;
}
LOGGER_DEBUG(logger, "successfully bound to TCP port %d", port);
return sock;
}
TCP_Server *new_TCP_server(const Logger *logger, const Random *rng, const Network *ns,
bool ipv6_enabled, uint16_t num_sockets,
const uint16_t *ports, const uint8_t *secret_key, Onion *onion, Forwarding *forwarding)
{
if (num_sockets == 0 || ports == nullptr) {
LOGGER_ERROR(logger, "no sockets");
return nullptr;
}
if (ns == nullptr) {
LOGGER_ERROR(logger, "NULL network");
return nullptr;
}
TCP_Server *temp = (TCP_Server *)calloc(1, sizeof(TCP_Server));
if (temp == nullptr) {
LOGGER_ERROR(logger, "TCP server allocation failed");
return nullptr;
}
temp->logger = logger;
temp->ns = ns;
temp->rng = rng;
temp->socks_listening = (Socket *)calloc(num_sockets, sizeof(Socket));
if (temp->socks_listening == nullptr) {
LOGGER_ERROR(logger, "socket allocation failed");
free(temp);
return nullptr;
}
#ifdef TCP_SERVER_USE_EPOLL
temp->efd = epoll_create(8);
if (temp->efd == -1) {
LOGGER_ERROR(logger, "epoll initialisation failed");
free(temp->socks_listening);
free(temp);
return nullptr;
}
#endif
const Family family = ipv6_enabled ? net_family_ipv6() : net_family_ipv4();
for (uint32_t i = 0; i < num_sockets; ++i) {
const Socket sock = new_listening_TCP_socket(logger, ns, family, ports[i]);
if (!sock_valid(sock)) {
continue;
}
#ifdef TCP_SERVER_USE_EPOLL
struct epoll_event ev;
ev.events = EPOLLIN | EPOLLET;
ev.data.u64 = sock.sock | ((uint64_t)TCP_SOCKET_LISTENING << 32);
if (epoll_ctl(temp->efd, EPOLL_CTL_ADD, sock.sock, &ev) == -1) {
continue;
}
#endif
temp->socks_listening[temp->num_listening_socks] = sock;
++temp->num_listening_socks;
}
if (temp->num_listening_socks == 0) {
free(temp->socks_listening);
free(temp);
return nullptr;
}
if (onion != nullptr) {
temp->onion = onion;
set_callback_handle_recv_1(onion, &handle_onion_recv_1, temp);
}
if (forwarding != nullptr) {
temp->forwarding = forwarding;
set_callback_forward_reply(forwarding, &handle_forward_reply_tcp, temp);
}
memcpy(temp->secret_key, secret_key, CRYPTO_SECRET_KEY_SIZE);
crypto_derive_public_key(temp->public_key, temp->secret_key);
bs_list_init(&temp->accepted_key_list, CRYPTO_PUBLIC_KEY_SIZE, 8);
return temp;
}
#ifndef TCP_SERVER_USE_EPOLL
non_null()
static void do_TCP_accept_new(TCP_Server *tcp_server)
{
for (uint32_t sock_idx = 0; sock_idx < tcp_server->num_listening_socks; ++sock_idx) {
for (uint32_t connection_idx = 0; connection_idx < MAX_INCOMING_CONNECTIONS; ++connection_idx) {
const Socket sock = net_accept(tcp_server->ns, tcp_server->socks_listening[sock_idx]);
if (accept_connection(tcp_server, sock) == -1) {
break;
}
}
}
}
#endif
non_null()
static int do_incoming(TCP_Server *tcp_server, uint32_t i)
{
TCP_Secure_Connection *const conn = &tcp_server->incoming_connection_queue[i];
if (conn->status != TCP_STATUS_CONNECTED) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling incoming TCP connection %d", i);
const int ret = read_connection_handshake(tcp_server->logger, conn, tcp_server->secret_key);
if (ret == -1) {
LOGGER_TRACE(tcp_server->logger, "incoming connection %d dropped due to failed handshake", i);
kill_TCP_secure_connection(conn);
return -1;
}
if (ret != 1) {
return -1;
}
const int index_new = tcp_server->unconfirmed_connection_queue_index % MAX_INCOMING_CONNECTIONS;
TCP_Secure_Connection *conn_old = conn;
TCP_Secure_Connection *conn_new = &tcp_server->unconfirmed_connection_queue[index_new];
if (conn_new->status != TCP_STATUS_NO_STATUS) {
LOGGER_ERROR(tcp_server->logger, "incoming connection %d would overwrite existing", i);
kill_TCP_secure_connection(conn_new);
}
move_secure_connection(conn_new, conn_old);
++tcp_server->unconfirmed_connection_queue_index;
return index_new;
}
non_null()
static int do_unconfirmed(TCP_Server *tcp_server, const Mono_Time *mono_time, uint32_t i)
{
TCP_Secure_Connection *const conn = &tcp_server->unconfirmed_connection_queue[i];
if (conn->status != TCP_STATUS_UNCONFIRMED) {
return -1;
}
LOGGER_TRACE(tcp_server->logger, "handling unconfirmed TCP connection %d", i);
uint8_t packet[MAX_PACKET_SIZE];
const int len = read_packet_TCP_secure_connection(tcp_server->logger, conn->con.ns, conn->con.sock, &conn->next_packet_length, conn->con.shared_key, conn->recv_nonce, packet, sizeof(packet), &conn->con.ip_port);
if (len == 0) {
return -1;
}
if (len == -1) {
kill_TCP_secure_connection(conn);
return -1;
}
return confirm_TCP_connection(tcp_server, mono_time, conn, packet, len);
}
non_null()
static bool tcp_process_secure_packet(TCP_Server *tcp_server, uint32_t i)
{
TCP_Secure_Connection *const conn = &tcp_server->accepted_connection_array[i];
uint8_t packet[MAX_PACKET_SIZE];
const int len = read_packet_TCP_secure_connection(tcp_server->logger, conn->con.ns, conn->con.sock, &conn->next_packet_length, conn->con.shared_key, conn->recv_nonce, packet, sizeof(packet), &conn->con.ip_port);
LOGGER_TRACE(tcp_server->logger, "processing packet for %d: %d", i, len);
if (len == 0) {
return false;
}
if (len == -1) {
kill_accepted(tcp_server, i);
return false;
}
if (handle_TCP_packet(tcp_server, i, packet, len) == -1) {
LOGGER_TRACE(tcp_server->logger, "dropping connection %d: data packet (len=%d) not handled", i, len);
kill_accepted(tcp_server, i);
return false;
}
return true;
}
non_null()
static void do_confirmed_recv(TCP_Server *tcp_server, uint32_t i)
{
while (tcp_process_secure_packet(tcp_server, i)) {
// Keep reading until an error occurs or there is no more data to read.
continue;
}
}
#ifndef TCP_SERVER_USE_EPOLL
non_null()
static void do_TCP_incoming(TCP_Server *tcp_server)
{
for (uint32_t i = 0; i < MAX_INCOMING_CONNECTIONS; ++i) {
do_incoming(tcp_server, i);
}
}
non_null()
static void do_TCP_unconfirmed(TCP_Server *tcp_server, const Mono_Time *mono_time)
{
for (uint32_t i = 0; i < MAX_INCOMING_CONNECTIONS; ++i) {
do_unconfirmed(tcp_server, mono_time, i);
}
}
#endif
non_null()
static void do_TCP_confirmed(TCP_Server *tcp_server, const Mono_Time *mono_time)
{
#ifdef TCP_SERVER_USE_EPOLL
if (tcp_server->last_run_pinged == mono_time_get(mono_time)) {
return;
}
tcp_server->last_run_pinged = mono_time_get(mono_time);
#endif
for (uint32_t i = 0; i < tcp_server->size_accepted_connections; ++i) {
TCP_Secure_Connection *conn = &tcp_server->accepted_connection_array[i];
if (conn->status != TCP_STATUS_CONFIRMED) {
continue;
}
if (mono_time_is_timeout(mono_time, conn->last_pinged, TCP_PING_FREQUENCY)) {
uint8_t ping[1 + sizeof(uint64_t)];
ping[0] = TCP_PACKET_PING;
uint64_t ping_id = random_u64(conn->con.rng);
if (ping_id == 0) {
++ping_id;
}
memcpy(ping + 1, &ping_id, sizeof(uint64_t));
const int ret = write_packet_TCP_secure_connection(tcp_server->logger, &conn->con, ping, sizeof(ping), true);
if (ret == 1) {
conn->last_pinged = mono_time_get(mono_time);
conn->ping_id = ping_id;
} else {
if (mono_time_is_timeout(mono_time, conn->last_pinged, TCP_PING_FREQUENCY + TCP_PING_TIMEOUT)) {
kill_accepted(tcp_server, i);
continue;
}
}
}
if (conn->ping_id != 0 && mono_time_is_timeout(mono_time, conn->last_pinged, TCP_PING_TIMEOUT)) {
kill_accepted(tcp_server, i);
continue;
}
send_pending_data(tcp_server->logger, &conn->con);
#ifndef TCP_SERVER_USE_EPOLL
do_confirmed_recv(tcp_server, i);
#endif
}
}
#ifdef TCP_SERVER_USE_EPOLL
non_null()
static bool tcp_epoll_process(TCP_Server *tcp_server, const Mono_Time *mono_time)
{
#define MAX_EVENTS 16
struct epoll_event events[MAX_EVENTS];
const int nfds = epoll_wait(tcp_server->efd, events, MAX_EVENTS, 0);
#undef MAX_EVENTS
for (int n = 0; n < nfds; ++n) {
const Socket sock = {(int)(events[n].data.u64 & 0xFFFFFFFF)};
const int status = (events[n].data.u64 >> 32) & 0xFF;
const int index = events[n].data.u64 >> 40;
if ((events[n].events & EPOLLERR) != 0 || (events[n].events & EPOLLHUP) != 0 || (events[n].events & EPOLLRDHUP) != 0) {
switch (status) {
case TCP_SOCKET_LISTENING: {
// should never happen
LOGGER_ERROR(tcp_server->logger, "connection %d was in listening state", index);
break;
}
case TCP_SOCKET_INCOMING: {
LOGGER_TRACE(tcp_server->logger, "incoming connection %d dropped", index);
kill_TCP_secure_connection(&tcp_server->incoming_connection_queue[index]);
break;
}
case TCP_SOCKET_UNCONFIRMED: {
LOGGER_TRACE(tcp_server->logger, "unconfirmed connection %d dropped", index);
kill_TCP_secure_connection(&tcp_server->unconfirmed_connection_queue[index]);
break;
}
case TCP_SOCKET_CONFIRMED: {
LOGGER_TRACE(tcp_server->logger, "confirmed connection %d dropped", index);
kill_accepted(tcp_server, index);
break;
}
}
continue;
}
if ((events[n].events & EPOLLIN) == 0) {
continue;
}
switch (status) {
case TCP_SOCKET_LISTENING: {
// socket is from socks_listening, accept connection
while (true) {
const Socket sock_new = net_accept(tcp_server->ns, sock);
if (!sock_valid(sock_new)) {
break;
}
const int index_new = accept_connection(tcp_server, sock_new);
if (index_new == -1) {
continue;
}
struct epoll_event ev;
ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
ev.data.u64 = sock_new.sock | ((uint64_t)TCP_SOCKET_INCOMING << 32) | ((uint64_t)index_new << 40);
if (epoll_ctl(tcp_server->efd, EPOLL_CTL_ADD, sock_new.sock, &ev) == -1) {
LOGGER_DEBUG(tcp_server->logger, "new connection %d was dropped due to epoll error %d", index, net_error());
kill_TCP_secure_connection(&tcp_server->incoming_connection_queue[index_new]);
continue;
}
}
break;
}
case TCP_SOCKET_INCOMING: {
const int index_new = do_incoming(tcp_server, index);
if (index_new != -1) {
LOGGER_TRACE(tcp_server->logger, "incoming connection %d was accepted as %d", index, index_new);
events[n].events = EPOLLIN | EPOLLET | EPOLLRDHUP;
events[n].data.u64 = sock.sock | ((uint64_t)TCP_SOCKET_UNCONFIRMED << 32) | ((uint64_t)index_new << 40);
if (epoll_ctl(tcp_server->efd, EPOLL_CTL_MOD, sock.sock, &events[n]) == -1) {
LOGGER_DEBUG(tcp_server->logger, "incoming connection %d was dropped due to epoll error %d", index, net_error());
kill_TCP_secure_connection(&tcp_server->unconfirmed_connection_queue[index_new]);
break;
}
}
break;
}
case TCP_SOCKET_UNCONFIRMED: {
const int index_new = do_unconfirmed(tcp_server, mono_time, index);
if (index_new != -1) {
LOGGER_TRACE(tcp_server->logger, "unconfirmed connection %d was confirmed as %d", index, index_new);
events[n].events = EPOLLIN | EPOLLET | EPOLLRDHUP;
events[n].data.u64 = sock.sock | ((uint64_t)TCP_SOCKET_CONFIRMED << 32) | ((uint64_t)index_new << 40);
if (epoll_ctl(tcp_server->efd, EPOLL_CTL_MOD, sock.sock, &events[n]) == -1) {
// remove from confirmed connections
LOGGER_DEBUG(tcp_server->logger, "unconfirmed connection %d was dropped due to epoll error %d", index, net_error());
kill_accepted(tcp_server, index_new);
break;
}
}
break;
}
case TCP_SOCKET_CONFIRMED: {
do_confirmed_recv(tcp_server, index);
break;
}
}
}
return nfds > 0;
}
non_null()
static void do_TCP_epoll(TCP_Server *tcp_server, const Mono_Time *mono_time)
{
while (tcp_epoll_process(tcp_server, mono_time)) {
// Keep processing packets until there are no more FDs ready for reading.
continue;
}
}
#endif
void do_TCP_server(TCP_Server *tcp_server, const Mono_Time *mono_time)
{
#ifdef TCP_SERVER_USE_EPOLL
do_TCP_epoll(tcp_server, mono_time);
#else
do_TCP_accept_new(tcp_server);
do_TCP_incoming(tcp_server);
do_TCP_unconfirmed(tcp_server, mono_time);
#endif
do_TCP_confirmed(tcp_server, mono_time);
}
void kill_TCP_server(TCP_Server *tcp_server)
{
if (tcp_server == nullptr) {
return;
}
for (uint32_t i = 0; i < tcp_server->num_listening_socks; ++i) {
kill_sock(tcp_server->ns, tcp_server->socks_listening[i]);
}
if (tcp_server->onion != nullptr) {
set_callback_handle_recv_1(tcp_server->onion, nullptr, nullptr);
}
if (tcp_server->forwarding != nullptr) {
set_callback_forward_reply(tcp_server->forwarding, nullptr, nullptr);
}
bs_list_free(&tcp_server->accepted_key_list);
#ifdef TCP_SERVER_USE_EPOLL
close(tcp_server->efd);
#endif
for (uint32_t i = 0; i < MAX_INCOMING_CONNECTIONS; ++i) {
wipe_secure_connection(&tcp_server->incoming_connection_queue[i]);
wipe_secure_connection(&tcp_server->unconfirmed_connection_queue[i]);
}
free_accepted_connection_array(tcp_server);
crypto_memzero(tcp_server->secret_key, sizeof(tcp_server->secret_key));
free(tcp_server->socks_listening);
free(tcp_server);
}
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