kern/169898: ifconfig(8) fails to set MTU on multiple interfaces.

[Jason Hellenthal]

>Number:         169898
>Category:       kern
>Synopsis:       ifconfig(8) fails to set MTU on multiple interfaces.
>Confidential:   no
>Severity:       non-critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jul 16 02:30:09 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Jason Hellenthal
>Release:        FreeBSD 8.3-STABLE i386
>Organization:
>Environment:
System: FreeBSD disbatch.DataIX.local 8.3-STABLE FreeBSD 8.3-STABLE #23 r238498: Sun Jul 15 15:34:30 EDT 2012 jh at DataIX.net:/usr/obj/usr/src/sys/DISBATCH i386

>Description:
When using ifconfig(8) to change MTU of an interface it is not allowed.

# ifconfig lagg0 mtu 1492
ifconfig: ioctl (set mtu): Invalid argument

# ifconfig dc0 mtu 1492
ifconfig: ioctl (set mtu): Invalid argument

# ifconfig dc1 mtu 1492
ifconfig: ioctl (set mtu): Invalid argument

# ifconfig pflog0 mtu 120
ifconfig: ioctl (set mtu): Invalid argument

# ifconfig ath0 mtu 1500
ifconfig: ioctl (set mtu): Invalid argument

>How-To-Repeat:

See description.

>Fix:

No workaround known.

>Release-Note:
>Audit-Trail:
>Unformatted: