no route to destination (temporary failure) leads to exception

[hannesm]

I just got the following on my xl console, and had to restart all the unikernels due to a temporary failure of the router (I suspect it rebootet). Could we handle this failure condition a bit more explicit (re-trying and emitting a log entry), please?

Tcp.Segment: TCP retransmission on timer seq = 452917760
IP.output: could not send to XX.YY.ZZ.XX: failed to contact gateway YY.YY.ZZ.ZZ
Fatal error: exception Ipv4.Make(Ethif)(Arpv4).Routing.No_route_to_destination_address(_)
Raised at file "map.ml", line 117, characters 16-25
Called from file "src/conv.ml", line 215, characters 10-37
Mirage exiting with status 2
Do_exit called!