Default route is sometimes erroneously removed

[lboclboc]

Sometimes we see that the default route that lies on eth0 is removed when the link of a local network using usb0 goes down. We are using version 9.4.1. on raspberry pi. See log below:

Oct 3 11:20:13 raspberry-01 dhcpcd5[400]: usb0: carrier lost Oct 3 11:20:13 raspberry-01 kernel: [ 1885.303189] usb 1-1.2: USB disconnect, device number 7 Oct 3 11:20:13 raspberry-01 kernel: [ 1885.303475] rndis_host 1-1.2:1.0 usb0: unregister 'rndis_host' usb-3f980000.usb-1.2, RNDIS device Oct 3 11:20:13 raspberry-01 dhcpcd5[400]: usb0: deleting route to 169.254.1.0/24 Oct 3 11:20:13 raspberry-01 dhcpcd5[400]: eth0: deleting route to 10.46.29.0/24 <- I think this is wrong Oct 3 11:20:13 raspberry-01 dhcpcd5[400]: eth0: deleting default route via 10.46.29.1 <- and this Oct 3 11:20:13 raspberry-01 dhcpcd5[400]: usb0: removing interface

[rsmarples]

That does look wrong.

[lboclboc]

Yes, I forgot to mention that we also have a number of DNAT iptables rules (static ones added at boot). If that somehow can cause problems. Not for port 67 or 68 though. Also its not just a carrier drop, its a whole device getting unplugged and replugged. This is part of our testing environment and the equipment is presented as a usb network device to the rpi.