kern/188032: IPv6 on lo never leaves 'tentative' state if configured with prefixlen 128

[Darren Baginski]

>Number:         188032
>Category:       kern
>Synopsis:       IPv6 on lo never leaves 'tentative' state if configured with prefixlen 128
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Mar 28 16:10:02 UTC 2014
>Closed-Date:
>Last-Modified:
>Originator:     Darren Baginski
>Release:        10.0-STABLE FreeBSD
>Organization:
>Environment:
FreeBSD freebsd10.local 10.0-STABLE FreeBSD 10.0-STABLE #1 r262603: Fri Feb 28 16:39:10 UTC 2014     root at freebsd10.local:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
IPv6 on lo never leaves 'tentative' state if configured with prefixlen 128.

Steps to reproduce.

# ifconfig lo8 create
# ifconfig lo8 up
# ifconfig lo8 inet6 fc00::ff prefixlen 128


# ifconfig lo8
lo8: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
        inet6 fc00::ff prefixlen 128 tentative 
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>


lo8 ipv6 stays 'tentative' stays forever and never become ping-able.

"Workaround" is to apply any other prefixlen, e.g. /127 
>How-To-Repeat:

# ifconfig lo8 create
# ifconfig lo8 up
# ifconfig lo8 inet6 fc00::ff prefixlen 128


# ifconfig lo8
lo8: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
        inet6 fc00::ff prefixlen 128 tentative 
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>

# ping fc00::ff
>Fix:
"Workaround" is to apply any other prefixlen, e.g. /127 

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