implement real lock around IPv6 reassembly, to avoid panic due to frag6_drain.  (lock performed on netbsd/openbsd only, as other *BSD does not lock during ip_reass)
implement real lock around IPv6 reassembly, to avoid panic due to
frag6_drain.  (lock performed on netbsd/openbsd only, as other *BSD does
not lock during ip_reass)

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame