index.js

const net = require("net");
const tunnelDataHandler = require("./tunnelDataHandler");
const logger = require("./logger");
const bridge = require("./bridge/connection");

//Persistance Collections
const database = require("./database/db.js");

const serverPort = process.env.GATEWAY_SERVER_PORT || 3001;

database.connectToDatabase();

function onError(clientSocket, error) {
	logger.warn(`Client socket error: ${error}`);
	logger.warn(`${clientSocket.remoteAddress}:${clientSocket.remotePort}`);
	try {
		bridge.deleteSocketConnectionBySocket(clientSocket);
	} catch (error) {
		logger.warn(error);
	}
}

function onEnd(clientSocket) {
	logger.verbose("Client socket closed.");
	logger.verbose(`${clientSocket.remoteAddress}:${clientSocket.remotePort}`);
	try {
		bridge.deleteSocketConnectionBySocket(clientSocket);
	} catch (error) {
		logger.warn(error);
	}
}

function onData(clientSocket, data) {
	try {
		tunnelDataHandler(clientSocket, data);
	} catch (error) {
		logger.warn(`Message process error: ${error}`);
	}
}

// Create a TCP server that listens for incoming connections
const planeTcpServer = net.createServer((clientSocket) => {
	logger.info(`Device connected: ${clientSocket.remoteAddress}:${clientSocket.remotePort}`);

	// Handle errors, remove socket from bridge if it is exists
	clientSocket.on("error", (error) => {
		onError(clientSocket, error);
	});

	// Handle the connection end event, remove socket from bridge if it is exists
	clientSocket.on("end", () => {
		onEnd(clientSocket);
	});

	// When data is received from a client, decrypt and pass to processing
	clientSocket.on("data", (data) => {
		onData(clientSocket, data);
	});
});

planeTcpServer.listen(serverPort, () => {
	logger.info(`ELFIN IoT TCP proxy server is listening on port ${serverPort}`);
});