openbsd/netbsd: implement hiwat/lowat on pmtud host route entries. allow non-validated too big message, if we are < lowat. allow validated too big message, if we are < hiwat. XXX pick a victim and allow validated too big message, if we are in lowat < x < hiwat.
openbsd/netbsd: implement hiwat/lowat on pmtud host route entries.
allow non-validated too big message, if we are < lowat.
allow validated too big message, if we are < hiwat.
XXX pick a victim and allow validated too big message, if we are in
lowat < x < hiwat.

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