Use rtisivalid(9) to check if the given (cached) route can be used.

Use rtisivalid(9) to check if the given (cached) route can be used.

Note that after calling rtalloc(9) we only check if a route has been
returned or not and do not check for its validity.  This cannot be
improved without a massive refactoring.

The kernel currently *do* use !RTF_UP route due to a mismatch between
the value of ifp->if_link_state and the IFF_UP|IFF_RUNNING code.

I'd explain the RTF_UP flag as follow:

.  If a cached route entry w/o RTF_UP is passed to ip{6,}_output(),
.  call rtalloc(9) to see if a better entry is present in the tree.

This is enough to support MPATH and route cache invalidation.

ok bluhm@