Google Compute Engine networking stopped working

[Benny Siegert <bsiegert%gmail.com@localhost>]

Hi!

I have a NetBSD VM with working networking in Google Compute Engine,
and a new one where it does not work.

GCE Networking has DHCP return a host address with a /32 netmask, plus
a gateway with a different address. The trick is that you also need a
host route to the gateway, directly over the interface.

The working setup is on this:

NetBSD 7.99.65 (DIAGNOSTIC) #0: Tue Mar 7 21:47:12 CET 2017

# /usr/pkg/sbin/dhcpcd --version
dhcpcd 6.11.5
Copyright (c) 2006-2016 Roy Marples
Compiled in features: INET IPv4LL INET6 DHCPv6 AUTH

# cat /etc/ifconfig.vioif0
!/usr/pkg/sbin/dhcpcd vioif0
!route add default `ifconfig vioif0 | awk '/inet / { print $2 }' | sed
's/[0-9]*$/1/'` -ifp vioif0

dhcpcd fails to set a default route, then it runs something like
# route add default 10.240.0.1 -ifp vioif0
# netstat -rnf inet
Routing tables
Internet:
Destination        Gateway            Flags    Refs      Use    Mtu Interface
default            10.240.0.1         UGS         -        -      -  vioif0
10.240.0.1/32      link#2             UC          -        -   1460  vioif0
10.240.0.3         127.0.0.1          UGHS        -        -   1460  lo0
10.240.0.3/32      link#2             UC          -        -      -  vioif0
127/8              127.0.0.1          UGRS        -        -  33624  lo0
127.0.0.1          lo0                UH          -        -  33624  lo0
# ifconfig vioif0
vioif0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        ec_capabilities=1<VLAN_MTU>
        ec_enabled=0
        address: 42:01:0a:f0:00:03
        inet 10.240.0.3 netmask 0xffffffff broadcast 10.240.0.3
        inet6 fe80::1811:269b:ecb0:bcdf%vioif0 prefixlen 64 scopeid 0x2

The machine where this is not working is a recent -8:

NetBSD 8.0_BETA (GENERIC.201708192310Z)

# dhcpcd --version
dhcpcd 7.0.0-rc1
Copyright (c) 2006-2017 Roy Marples
Compiled in features: INET ARP IPv4LL INET6 DHCPv6 AUTH


From a non-configured network, I run dhcpcd:
# dhcpcd vioif0
DUID 00:01:00:01:21:2d:7a:15:52:54:00:12:34:56
vioif0: IAID 0a:f0:00:02
vioif0: rebinding lease of 10.240.0.2
vioif0: soliciting an IPv6 router
vioif0: leased 10.240.0.2 for 86400 seconds
vioif0: adding route to 10.240.0.2/32
vioif0: adding host route to 255.255.255.255
vioif0: adding default route via 10.240.0.1
forked to background, child pid 336

# netstat -rnf inet
Routing tables
Internet:
Destination        Gateway            Flags    Refs      Use    Mtu Interface
default            10.240.0.1         UGS         -        -   1460  vioif0
10.240.0.2         link#2             UHC         -        -   1460  vioif0
10.240.0.2/32      link#2             UC          -        -      -  vioif0
127.0.0.1          lo0                UHl         -        -  33624  lo0
255.255.255.255    link#2             UHCS        -        -   1460  vioif0
# ping 10.240.0.1
PING 10.240.0.1 (10.240.0.1): 56 data bytes
ping: sendto: Invalid argument
# ifconfig vioif0
vioif0: flags=0x8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        ec_capabilities=1<VLAN_MTU>
        ec_enabled=0
        address: 42:01:0a:f0:00:02
        inet 10.240.0.2/32 broadcast 10.240.0.2 flags 0x0
        inet6 fe80::7a06:ce6a:2f4a:8e44%vioif0/64 flags 0x0 scopeid 0x2

This works:

# route delete default
delete net default
# route  add  -interface -host  10.240.0.1 10.240.0.2
add host 10.240.0.1: gateway 10.240.0.2
# route add default 10.240.0.1
add net default: gateway 10.240.0.1

How can I get dhcpcd to do the right thing?

--Benny.