From: Alan Robertson <redacted>
Date: Thu, 30 May 2013 16:01:55 -0600

ndo_dflt_fdb_del is checking for a condition which is opposite that
which ndo_dflt_fdb_add enforces.  ndo_dflt_fdb_add declares an error
if (ndm->ndm_state && !(ndm->ndm_state) & NUD_PERMANENT)) - that is, if the
entry is static.  This is consistent with the failure error message.

On the other hand, ndo_dflt_del() declares an error
if (ndm_state & NUD_PERMANENT) - which is inconsistent with the add
precondition, and inconsistent with its failure message text.
As it is now, you can't delete any entry which add allows to be added -
so entry deletion always fails.

Signed-off-by: Alan Robertson <redacted>

What about the ->ndm_state part of the add() test?  Why not include
that in the del() check?