To make ND6 mp-safe, the life time of struct llinfo_nd6 *ln =

To make ND6 mp-safe, the life time of struct llinfo_nd6 *ln =
rt->rt_llinfo has to be guaranteed.  Replace the complicated logic
in nd6_rtrequest() case RTM_ADD with what we have in ARP.  This
avoids accessing ln here.
Digging through histroy shows a lot of refactoring that makes
rt_expire handling in RTM_ADD obsolete.  Just initialize it to 0.
Cloning and local routes should never expire.  If RTF_LLINFO is
set, ln should not be NULL.  So nd6_llinfo_settimer() was not reached
in this case.
While there, remove obsolete comments and #if 0 code that never
worked.
OK kn@ claudio@