Bug in UDP communikation

Problem: If you use a broadcast IP in the UDP settings, the Data is not send to the network, instead it goes to loopback.

Solution: In FormGPS after line 880 enable broadcasts for both sockets:
sendSocket.EnableBroadcast = true;
recvSocket.EnableBroadcast = true;

Dokumentation: Socket.EnableBroadcast Eigenschaft (System.Net.Sockets) | Microsoft Docs

Actually the bug, from what i understand is only in the arduino code. It needs broadcast whereas AOG is not needed, it send directly to the module port number.

Or am i misunderstanding that? Seems to work fine port specific from AOG while being broadcast (no choice) from arduino.

Yes misunderstanding, aog/Windows is not sending the messages to the right interface without this option when a broadcast IP is configured (and that’s needed in many usecases).

Data goes to loopback instead of WiFi. I can capture and attach some .pcap files if you want.

The problem is on the layer 3 (ip), not on layer 4 (udp/port numbers).

I am curious, why does it work on ethernet just the way it is?


So is this a wifi issue only?

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Two theories (untested):

  • One of the last Windows 10 started to enforce this behavior
  • It only happens if there is no default route on that interface (in my test-Setup, but valid for local only communication)
  • After testing again: Windows decides on a unknown base if broadcasts are forwarded or not. Just tried to screenshot it, this time it seems to work. (Should have made a screenshot two days ago when I spent one afternoon chasing the problem why I did not received any PGN over wifi).

But in either case: I think implementing the API behavior can not be a negative thing, especially if it’s as easy as in this case, so we won’t rely on some undocumented behavior.

I have added those 2 properties. I find the networking stuff pretty tricky. Mostly because i don’t understand it very well.

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Hello, I have a UDP Problem, the Check SUM is green, but i dont recieve any data from Arduin, no steering angle no remote switch etc…
What could be the Problem?

Regards, Peter