Function NetworkServer_Tick

src/network/network_server.cpp:1679–1810

* This is called every tick if this is a _network_server * @param send_frame Whether to send the frame to the clients. */

 * @param send_frame Whether to send the frame to the clients.
 */
void NetworkServer_Tick(bool send_frame)
{
#ifndef ENABLE_NETWORK_SYNC_EVERY_FRAME
	bool send_sync = false;
#endif

#ifndef ENABLE_NETWORK_SYNC_EVERY_FRAME
	if (_frame_counter >= _last_sync_frame + _settings_client.network.sync_freq) {
		_last_sync_frame = _frame_counter;
		send_sync = true;
	}
#endif

	/* Now we are done with the frame, inform the clients that they can
	 *  do their frame! */
	for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {
		/* We allow a number of bytes per frame, but only to the burst amount
		 * to be available for packet receiving at any particular time. */
		cs->receive_limit = std::min<size_t>(cs->receive_limit + _settings_client.network.bytes_per_frame,
				_settings_client.network.bytes_per_frame_burst);

		/* Check if the speed of the client is what we can expect from a client */
		uint lag = NetworkCalculateLag(cs);
		switch (cs->status) {
			case NetworkClientSocket::STATUS_ACTIVE:
				if (lag > _settings_client.network.max_lag_time) {
					/* Client did still not report in within the specified limit. */

					if (cs->last_packet + std::chrono::milliseconds(lag * MILLISECONDS_PER_TICK) > std::chrono::steady_clock::now()) {
						/* A packet was received in the last three game days, so the client is likely lagging behind. */
						IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because the client's game state is more than {} ticks behind.", cs->client_id, cs->GetClientIP(), lag);
					} else {
						/* No packet was received in the last three game days; sounds like a lost connection. */
						IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because the client did not respond for more than {} ticks.", cs->client_id, cs->GetClientIP(), lag);
					}
					cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
					continue;
				}

				/* Report once per time we detect the lag, and only when we
				 * received a packet in the last 2 seconds. If we
				 * did not receive a packet, then the client is not just
				 * slow, but the connection is likely severed. Mentioning
				 * frame_freq is not useful in this case. */
				if (lag > (uint)Ticks::DAY_TICKS && cs->lag_test == 0 && cs->last_packet + std::chrono::seconds(2) > std::chrono::steady_clock::now()) {
					IConsolePrint(CC_WARNING, "[{}] Client #{} is slow, try increasing [network.]frame_freq to a higher value!", _frame_counter, cs->client_id);
					cs->lag_test = 1;
				}

				if (cs->last_frame_server - cs->last_token_frame >= _settings_client.network.max_lag_time) {
					/* This is a bad client! It didn't send the right token back within time. */
					IConsolePrint(CC_WARNING, "Client #{} (IP: {}) is dropped because it fails to send valid acks.", cs->client_id, cs->GetClientIP());
					cs->SendError(NETWORK_ERROR_TIMEOUT_COMPUTER);
					continue;
				}
				break;

			case NetworkClientSocket::STATUS_INACTIVE: