Static interface routes for IP address on different subnet doesn't send an ARP who-has

[Peter Kieser <peter%kieser.ca@localhost>]

Hello,

I have an ISP that requires that I use a subnet mask of 255.255.255.255 
(/32) which requires that I add a static interface route for the gateway 
IP address because it's on a different subnet 
(http://help.ovh.ie/BridgeClient.) In Linux and FreeBSD this works as 
intended, and the network stack sends an ARP request for the gateway IP 
address when a static route is added.

On NetBSD, the network stack seems to make up a random MAC address and I 
don't see an ARP who-has request sent. Below, you can see that the MAC 
address of the gateway (198.50.219.62) is correct when the subnet is set 
to /27:

watson# arp -a
? (198.50.219.62) at 52:54:00:07:a6:f6 on vioif0
watson# ifconfig vioif0
vioif0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    address: 52:54:00:24:c2:c3
    inet 198.50.219.49 netmask 0xffffffe0 broadcast 198.50.219.63
    inet6 fe80::5054:ff:fe24:c2c3%vioif0 prefixlen 64 scopeid 0x1

If I set the subnet and broadcast domain how my ISP wants it, and follow 
http://www.netbsd.org/docs/network/#nonsubnetgateway the MAC address is 
replaced with garbage data:

watson# ifconfig vioif0 inet 198.50.219.49 netmask 255.255.255.255 
broadcast 198.50.219.49
watson# route add -host 198.50.219.62 -link -iface vioif0
add host 198.50.219.62: gateway vioif0
watson# ping 198.50.219.62
PING 198.50.219.62 (198.50.219.62): 48 data bytes
^C
----198.50.219.62 PING Statistics----
3 packets transmitted, 0 packets received, 100.0% packet loss
watson# arp -a
? (198.50.219.62) at 76:69:6f:69:66:30:00:0e:00:00:00:00 on vioif0 permanent

Now, if I add the MAC address of the gateway (which isn't a reasonable 
solution, since my ISP has HRSP and other failovers setup) everything 
works out:

watson# route add -host 198.50.219.62 -link -iface vioif0:52540007a6f6

Does anyone have any idea how to get this configuration to work without 
the MAC address of the gateway being specified for the route? I feel 
like this is a bug, as with Linux and FreeBSD this configuration (while 
I believe it's not particular sane) works just fine, the operating 
system does an ARP who-has request and you can access the default gateway.

Thank you,

-Peter

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