cayenn.go

package main

import (
	"bufio"
	"encoding/json"
	"log"
	"net"
	"regexp"
	"strings"
)

type Addr struct {
	IP       string
	Port     int
	Network  string
	TcpOrUdp string
}

type DataAnnounce struct {
	Addr     Addr
	Announce string
	Widget   string
	JsonTag  string
	DeviceId string
}

type ClientAnnounceMsg struct {
	Announce   string
	Widget     string
	MyDeviceId string
	JsonTag    string
}

// This is the UDP packet sent back from the server (us)
// to the client saying "hey we got your announce, this is
// who we are and our IP in case you want to create a TCP
// socket conn back to us for reliable conn"
type ServerAnnounceResponseMsg struct {
	Announce     string
	Widget       string
	YourDeviceId string
	ServerIp     string
	JsonTag      string
}

func udpServerRun() {

	/* Lets prepare a address at any address at port 8988*/
	ServerAddr, err := net.ResolveUDPAddr("udp", ":8988")
	if err != nil {
		log.Println("Error: ", err)
		return
	}

	/* Now listen at selected port */
	ServerConn, err := net.ListenUDP("udp", ServerAddr)
	if err != nil {
		log.Println("Error: ", err)
		return
	}
	defer ServerConn.Close()

	log.Println("UDP server running on port 8988 to listen for incoming device announcements and unguaranteed data.")
	buf := make([]byte, 1024)

	for {
		n, addr, err := ServerConn.ReadFromUDP(buf)

		if err != nil {
			log.Println("Error: ", err)
		} else {
			log.Println("Received ", string(buf[0:n]), " from ", addr)

			m := DataAnnounce{}
			m.Addr.IP = addr.IP.String()
			m.Addr.Network = addr.Network()
			m.Addr.Port = addr.Port
			m.Addr.TcpOrUdp = "udp"

			// if the udp message was from us, i.e. we sent out a broadcast so
			// we got a copy back, just ignore
			MyIp := ServerConn.LocalAddr().String()
			// drop port, cuz we don't care about it. we have known ports
			re := regexp.MustCompile(":\\d+$")
			MyIp = re.ReplaceAllString(MyIp, "")
			externIP, _ := externalIP()
			// print("Checking if from me ", addr.IP.String(), "<>", externIP)
			if addr.IP.String() == externIP {
				log.Println("Got msg back from ourself, so dropping.")
				continue
			}

			var am ClientAnnounceMsg
			err := json.Unmarshal([]byte(buf[0:n]), &am)
			if err != nil {
				log.Println("Err unmarshalling UDP inbound message from device. err:", err)
				continue
			}
			m.Announce = am.Announce
			m.Widget = am.Widget
			m.JsonTag = am.JsonTag
			m.DeviceId = am.MyDeviceId

			// send message to websocket clients, i.e. ChiliPeppr
			bm, err := json.Marshal(m)
			if err == nil {
				h.broadcastSys <- bm
			}

			// send back our own AnnounceRecv
			// but only if the incoming message was an "Announce":"i-am-a-client"
			//re2 := regexp.MustCompile('"Announce":"i-am-a-client"')
			//if re2.MatchString()
			if am.Announce == "i-am-a-client" {

				var arm ServerAnnounceResponseMsg
				arm.Announce = "i-am-your-server"
				arm.YourDeviceId = am.MyDeviceId
				arm.ServerIp = ServerConn.LocalAddr().String()
				arm.Widget = am.Widget
				//arm.JsonTag = am.JsonTag

				// we send back reverse acknowledgement on both UDP and TCP
				// but long term we should likely just send a TCP response back
				// because Cayenn devices will likely long term need to store what
				// server they are interacting with, however, the debate is i have
				// Cayenn devices mostly just sending back broadcast messages to entire
				// network and it's working well
				sendUdp(arm, m.Addr.IP, ":8988")
				go sendTcp(arm, m.Addr.IP, ":8988")

				// cayennSendTcpMsg(m.Addr.IP, ":8988", bmsg)
				// go makeTcpConnBackToDevice(m.Addr.IP)
			} else {
				log.Println("The incoming msg was not an i-am-client announce so not sending back response")
			}
		}
	}
}

// Called from hub.go as entry point
func cayennSendUdp(s string) {
	// we get here if a client sent into spjs the command
	// cayenn-sendudp 192.168.1.12 any-msg-to-end-of-line
	args := strings.SplitN(s, " ", 3)

	// make sure we got 3 args
	if len(args) < 3 {
		spErr("Error parsing cayenn-sendudp. Returning. msg:" + s)
		return
	}

	ip := args[1]
	if len(ip) < 7 {
		spErr("Error parsing IP address for cayenn-sendudp. Returning. msg:" + s)
		return
	}
	msg := args[2]
	log.Println("cayenn-sendudp ip:", ip, "msg:", msg)
	cayennSendUdpMsg(ip, ":8988", msg)
}

func cayennSendUdpMsg(ipaddr string, port string, msg string) {

	// This method sends a message to a specific IP address / port over UDP
	var service = ipaddr + port

	conn, err := net.Dial("udp", service)

	if err != nil {
		log.Println("Could not resolve udp address or connect to it on ", service)
		log.Println(err)
		return
	}
	defer conn.Close()

	log.Println("Connected to udp server at ", service)

	n, err := conn.Write([]byte(msg))
	if err != nil {
		log.Println("error writing data to server", service)
		log.Println(err)
		return
	}

	if n > 0 {
		log.Println("Wrote ", n, " bytes to server at ", service)
	} else {
		log.Println("Wrote 0 bytes to server. Huh?")
	}
}

// This method is similar to cayennSendUdp but it takes in a struct and json
// serializes it
func sendUdp(sarm ServerAnnounceResponseMsg, ipaddr string, port string) {

	var service = ipaddr + port

	conn, err := net.Dial("udp", service)

	if err != nil {
		log.Println("Could not resolve udp address or connect to it on ", service)
		log.Println(err)
		return
	}
	defer conn.Close()

	log.Println("Connected to udp server at ", service)

	// add our server ip to packet because esp8266 and Lua make it near impossible
	// to determine the ip the udp packet came from, so we'll include it in the payload
	sarm.ServerIp = conn.LocalAddr().String()
	// drop port, cuz we don't care about it. we have known ports
	re := regexp.MustCompile(":\\d+$")
	sarm.ServerIp = re.ReplaceAllString(sarm.ServerIp, "")

	bmsg, err := json.Marshal(sarm)
	if err != nil {
		log.Println("Error marshalling json for sarm:", sarm, "err:", err)
		return
	}

	n, err := conn.Write([]byte(bmsg))
	if err != nil {
		log.Println("error writing data to server", service)
		log.Println(err)
		return
	}

	if n > 0 {
		log.Println("Wrote ", n, " bytes to server at ", service)
	} else {
		log.Println("Wrote 0 bytes to server. Huh?")
	}

}

func makeTcpConnBackToDevice(ipaddr string) {

	var ip = ipaddr + ":8988"
	conn, err := net.Dial("tcp", ip)
	log.Println("Making TCP connection to:", ip)

	if err != nil {
		log.Println("Error trying to make TCP conn. err:", err)
		return
	}
	defer func() {
		log.Println("Closing TCP conn to:", ip)
		conn.Close()
	}()

	n, err := conn.Write([]byte("hello"))
	if err != nil {
		log.Println("Write to server failed:", err.Error())
		return
	}

	log.Println("Wrote n:", n, "bytes to server")

	connbuf := bufio.NewReader(conn)
	for {
		str, err := connbuf.ReadString('\n')
		if len(str) > 0 {
			log.Println("Got msg on TCP client from ip:", ip)
			log.Println(str)
			h.broadcastSys <- []byte(str)
		}

		if err != nil {
			break
		}
	}
}

// Called from hub.go as entry point
func cayennSendTcp(s string) {
	// we get here if a client sent into spjs the command
	// cayenn-sendtcp 192.168.1.12 any-msg-to-end-of-line
	args := strings.SplitN(s, " ", 3)

	// make sure we got 3 args
	if len(args) < 3 {
		spErr("Error parsing cayenn-sendtcp. Returning. msg:" + s)
		return
	}

	ip := args[1]
	if len(ip) < 7 {
		spErr("Error parsing IP address for cayenn-sendtcp. Returning. msg:" + s)
		return
	}
	msg := args[2]
	log.Println("cayenn-sendtcp ip:", ip, "msg:", msg)
	cayennSendTcpMsg(ip, ":8988", msg)
}

// For now just connect, send, and then disconnect. This keeps stuff simple
// but it does create overhead. However, it is similar to RESTful web calls
func cayennSendTcpMsg(ipaddr string, port string, msg string) {

	// This method sends a message to a specific IP address / port over TCP
	var service = ipaddr + port

	conn, err := net.Dial("tcp", service)
	log.Println("Making TCP connection to:", service)

	if err != nil {
		log.Println("Error trying to make TCP conn. err:", err)
		return
	}
	defer func() {
		log.Println("Closing TCP conn to:", service)
		conn.Close()
	}()

	n, err := conn.Write([]byte(msg))
	if err != nil {
		log.Println("Write to server failed:", err.Error())
		return
	}

	log.Println("Wrote n:", n, "bytes to server")

	// close connection immediately
	conn.Close()

	//	connbuf := bufio.NewReader(conn)
	//	for {
	//		str, err := connbuf.ReadString('\n')
	//		if len(str) > 0 {
	//			log.Println("Got msg on TCP client from ip:", service)
	//			log.Println(str)
	//			h.broadcastSys <- []byte(str)
	//		}

	//		if err != nil {
	//			break
	//		}
	//	}

}

// This method is similar to cayennSendTcp but it takes in a struct and json
// serializes it
func sendTcp(sarm ServerAnnounceResponseMsg, ipaddr string, port string) {

	// This method sends a message to a specific IP address / port over TCP
	var service = ipaddr + port

	conn, err := net.Dial("tcp", service)
	log.Println("Making TCP connection to:", service)

	if err != nil {
		log.Println("Error trying to make TCP conn. err:", err)
		return
	}
	defer func() {
		log.Println("Closing TCP conn to:", service)
		conn.Close()
	}()

	// add our server ip to packet because esp8266 and Lua make it near impossible
	// to determine the ip the udp packet came from, so we'll include it in the payload
	sarm.ServerIp = conn.LocalAddr().String()
	// drop port, cuz we don't care about it. we have known ports
	re := regexp.MustCompile(":\\d+$")
	sarm.ServerIp = re.ReplaceAllString(sarm.ServerIp, "")

	bmsg, err := json.Marshal(sarm)
	if err != nil {
		log.Println("Error marshalling json for sarm:", sarm, "err:", err)
		return
	}

	n, err := conn.Write(bmsg)
	if err != nil {
		log.Println("Write to server failed:", err.Error())
		return
	}

	log.Println("Wrote n:", n, "bytes to server")

	// close connection immediately
	conn.Close()
}

func tcpServerRun() {

	ServerAddr, err := net.ResolveTCPAddr("tcp", ":8988")
	if err != nil {
		log.Println("Error: ", err)
		return
	}

	// Listen for incoming connections on all/any IP addresses
	// on port 8988
	l, err := net.ListenTCP("tcp", ServerAddr)
	if err != nil {
		log.Println("Error listening:", err.Error())
	}

	// Close the listener when the application closes.
	defer l.Close()

	log.Println("TCP server running on port 8988 to listen for incoming guaranteed device messages.")

	for {
		// Listen for an incoming connection.
		ServerConn, err := l.Accept()
		if err != nil {
			log.Println("Error accepting: ", err.Error())
		}
		// Handle connections in a new goroutine.
		go handleTcpRequest(ServerConn)
	}
}

// Handles incoming requests.
func handleTcpRequest(conn net.Conn) {

	// Make a buffer to hold incoming data.
	buf := make([]byte, 1024)

	// Read the incoming connection into the buffer.
	reqLen, err := conn.Read(buf)
	if err != nil {
		log.Println("Error reading incoming TCP data:", err.Error(), reqLen)
		return
	}

	// Send a response back to person contacting us.
	//  conn.Write([]byte("Message received."))

	addr := conn.RemoteAddr()
	log.Println("TCP Received ", string(buf[0:reqLen]), " from ", addr)

	m := DataAnnounce{}
	m.Addr.IP = addr.String()
	m.Addr.Network = addr.Network()
	//	m.Addr.Port = addr.Port
	m.Addr.TcpOrUdp = "tcp"

	var am ClientAnnounceMsg
	err2 := json.Unmarshal([]byte(buf[0:reqLen]), &am)
	if err2 != nil {
		log.Println("Err unmarshalling TCP inbound message from device. err:", err2)
		return
	}
	m.Announce = am.Announce
	m.Widget = am.Widget
	m.JsonTag = am.JsonTag
	m.DeviceId = am.MyDeviceId

	// send message to websocket clients, i.e. ChiliPeppr
	bm, err := json.Marshal(m)
	if err == nil {
		h.broadcastSys <- bm
	}

	// Close the connection when you're done with it.
	conn.Close()
}