DTLSServer

Overview ¶

This class is used to store the state of a DTLS server. Upon Instance.Setup it converts connected graphics.gd/classdb/PacketPeerUDP to graphics.gd/classdb/PacketPeerDTLS accepting them via Instance.TakeConnection as DTLS clients. Under the hood, this class is used to store the DTLS state and cookies of the server. The reason of why the state and cookies are needed is outside of the scope of this documentation.

Below a small example of how to use it:

package main

import (
	"fmt"

	"graphics.gd/classdb/CryptoKey"
	"graphics.gd/classdb/DTLSServer"
	"graphics.gd/classdb/Node"
	"graphics.gd/classdb/PacketPeerDTLS"
	"graphics.gd/classdb/Resource"
	"graphics.gd/classdb/TLSOptions"
	"graphics.gd/classdb/UDPServer"
	"graphics.gd/classdb/X509Certificate"
	"graphics.gd/variant/Float"
)

type ServerDTLS struct {
	Node.Extension[ServerDTLS]

	dtls  DTLSServer.Instance
	udp   UDPServer.Instance
	peers []PacketPeerDTLS.Instance
}

func (srv *ServerDTLS) Ready() {
	srv.udp.Listen(4242)
	var key = Resource.Load[CryptoKey.Instance]("key.key")
	var cert = Resource.Load[X509Certificate.Instance]("cert.crt")
	srv.dtls.Setup(TLSOptions.Server(key, cert))
}

func (srv *ServerDTLS) Process(delta Float.X) {
	for srv.udp.IsConnectionAvailable() {
		var peer = srv.udp.TakeConnection()
		var dtlsPeer = srv.dtls.TakeConnection(peer)
		if dtlsPeer.GetStatus() != PacketPeerDTLS.StatusHandshaking {
			continue // It is normal that 50%!o(MISSING)f the connections fails due to cookie exchange.
		}
		fmt.Println("Peer connected!")
		srv.peers = append(srv.peers, dtlsPeer)
	}
	for _, p := range srv.peers {
		p.Poll() // Must poll to update the state.
		if p.GetStatus() == PacketPeerDTLS.StatusConnected {
			for p.AsPacketPeer().GetAvailablePacketCount() > 0 {
				fmt.Println("Received message from client: ", string(p.AsPacketPeer().GetPacket()))
				p.AsPacketPeer().PutPacket([]byte("Hello DTLS client"))
			}
		}
	}
}

package main

import (
	"fmt"

	"graphics.gd/classdb/Node"
	"graphics.gd/classdb/PacketPeerDTLS"
	"graphics.gd/classdb/PacketPeerUDP"
	"graphics.gd/variant/Float"
)

type ClientDTLS struct {
	Node.Extension[ClientDTLS]

	dtls PacketPeerDTLS.Instance
	udp  PacketPeerUDP.Instance

	connected bool
}

func (srv *ClientDTLS) Ready() {
	srv.udp.ConnectToHost("127.0.0.1", 4242)
	srv.dtls.ConnectToPeer(srv.udp, "") // Use hostname in production for certificate validation!
}

func (srv *ClientDTLS) Process(delta Float.X) {
	srv.dtls.Poll()
	if srv.dtls.GetStatus() == PacketPeerDTLS.StatusConnected {
		if !srv.connected {
			// Try to contact server
			srv.dtls.AsPacketPeer().PutPacket([]byte("The Answer Is... 42!"))
		}
		for srv.dtls.AsPacketPeer().GetAvailablePacketCount() > 0 {
			fmt.Println("Connected: " + string(srv.dtls.AsPacketPeer().GetPacket()))
			srv.connected = true
		}
	}
}