UdpLink crashes on receiving a DatagramReq in UnetStack3

[shortstheory]

I am using a simple UnetAgent:

class DummyAgent extends UnetAgent {
    void startup() {
      
        def link = agentForService Services.LINK
        subscribe link
    }
    Message processRequest(Message msg) {
        return msg
    }

    void processMessage(Message msg) {
      println "Received Msg"
    }
}

My simulation script is as follows:

platform = RealTimePlatform

simulate  {
  node '1', address: 1, location: [0, 0, 0], shell: true, stack: { container ->
    container.add 'da', new DummyAgent()
    container.add 'link', new UdpLink()
    container.add 'router', new org.arl.unet.net.Router()
  }
  node '2', address: 2, location: [200.m, 0, 0], shell: 5001, stack: { container ->
    container.add 'da', new DummyAgent()
    container.add 'link', new UdpLink()
    container.add 'router', new Router()
  }
  node '3', address: 3, location: [400.m, 0, 0], shell: 5002, stack: { container ->
    container.add 'da', new DummyAgent()
    container.add 'link', new UdpLink()
    container.add 'router', new Router()
  }
}

On running link << new org.arl.unet.DatagramReq(to: 3, reliability: true) on Node 1, I get the following exception:

Exception in thread "link [monitor]" org.arl.fjage.FjageError: request() should only be called from agent thread 44, but called from 47
	at org.arl.fjage.Agent.request(Agent.java:528)
	at org.arl.unet.NodeAddressCache.update(NodeAddressCache.java:79)
	at org.arl.unet.NodeAddressCache.getAddress(NodeAddressCache.java:42)
	at org.arl.unet.link.UdpLink.receiveDatagram(UdpLink.java:353)
	at org.arl.unet.link.UdpLink.access$700(UdpLink.java:17)
	at org.arl.unet.link.UdpLink$RxMonitor.run(UdpLink.java:449)

Surprisingly, I still get the DDN notification on the shell despite the error. However, I get no Datagram notifications in my DtnLink simulations.

[shortstheory]

This also sometimes leads to a NullPointerException in UdpLink which causes my DtnLink to crash. I have not yet figured out how to reproduce this NPE.

[mchitre]

Tested on latest UnetStack3 beta and seems OK. I guess it got fixed along the way :-)