kern/51179: lingering arp entries

[mlelstv%serpens.de@localhost]

>Number:         51179
>Category:       kern
>Synopsis:       lingering arp entries
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun May 29 09:30:00 +0000 2016
>Originator:     Michael van Elst
>Release:        NetBSD 7.99.29
>Organization:
	
>Environment:
	
	
System: NetBSD tazz 7.99.29 NetBSD 7.99.29 (TAZZ) #5: Sat May 28 08:36:59 CEST 2016 mlelstv@gossam:/home/netbsd-current/obj.amd64/home/netbsd-current/src/sys/arch/amd64/compile/TAZZ amd64
Architecture: x86_64
Machine: amd64
>Description:
arp entries become undeletable when an interface is shut down.

The system has two interfaces connected to the same network. One
interface is configured. Shutting down the active interface and
configuring the second interface causes arp entries for systems
on the network associated with both interfaces, e.g.

? (10.28.5.17) at b8:27:eb:12:34:56 on iwn0
? (10.28.5.17) at b8:27:eb:12:34:56 on wm0

You can however only delete one entry, the other persists and
is still used by the network stack.

# arp -d 10.28.5.17
# arp -na | grep 10.28.5.17
? (10.28.5.17) at b8:27:eb:12:34:56 on iwn0
# arp -d 10.28.5.17
arp: writing to routing socket: No such file or directory
# arp -na | grep 10.28.5.17
? (10.28.5.17) at b8:27:eb:12:34:56 on iwn0



>How-To-Repeat:
See above
>Fix:
	

>Unformatted: