sysID exclusion

[dogmaphobic]

The router code checks to see if the target endpoint sysID should be excluded or not based on the command/message. However, if it never received anything on that endpoint, it does not know of any sysID and the existing logic was to always reject.

The Vantage Snap sends MAVLink through one port and receives on another. When going through the router, the receiving port endpoint having never sent anything, would always get excluded. That caused commands sent to it never to go through.

This is a hack at best as I do not fully understand all the gyrations this code is going through. Don't merge it unless it's fully tested on a normal system.

[LorenzMeier]

Thanks for figuring this out. This is not acceptable and it should not be merged here or upstream.

[jbeyerstedt]

The issue is, that messages with a target "address" will be filtered according to the list of known components on each endpoint. We also have this issue with our D2X bridge utility, which uses two separate sockets for RX and TX data, while mavlink-router assumes that both ways are running on the same socket.

So you might have a look at mavlink-router#235, which adds another mode to the endpoint, where both, the "listening" and "target" address, can be specified. (It even works with IPv6 multicast groups (IPv4 needs manual configuration of the network interface), because that was my first use case, which in the end didn't work out.)