kern/40133: Changing the connected subnet route results in error when removing origonal IP

[roy%marples.name@localhost]

>Number:         40133
>Category:       kern
>Synopsis:       Changing the connected subnet route results in error when 
>removing origonal IP
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Dec 07 18:05:00 +0000 2008
>Originator:     Roy Marples
>Release:        5.0_BETA
>Organization:
>Environment:
NetBSD localhost 5.0_BETA NetBSD 5.0_BETA (UBERSERVER) #3: Sat Nov 22 08:09:44 
GMT 2008  
roy%uberserver.marples.name@localhost:/usr/obj/sys/arch/amd64/compile/UBERSERVER
 amd64
>Description:
If you have two IP addresses on two interfaces to the same subnet we can 
logically only have one route to the subnet over an interface. Using the route 
change command we CAN change the interface used for the subnet, however it is 
then impossible to remove or re-add the address/subnet to the first interface.
>How-To-Repeat:
!/bin/sh -x

ifp1=re0
ifa1=192.168.1.10/24
ifp2=ral0
ifa2=192.168.1.20/24
snr=192.168.1.0/24

# Configure ifa's
ifconfig $ifp1 alias $ifa1
ifconfig $ifp2 alias $ifa2

# Connect ifp2
route change $snr -ifp $ifp2

# Remove and then add ifa1. The add should fail - this is a bug.
ifconfig $ifp1 -alias $ifa1
ifconfig $ifp1 alias $ifa1
ifconfig $ifp1

# Remove all aliases now
route delete $snr
ifconfig $ifp1 -alias $ifa1
ifconfig $ifp2 -alias $ifa2

>Fix: