Test all 64 bits of sender's link-local addresses.
Test all 64 bits of sender's link-local addresses.

Link-local addresses are defined as being in fe80::/10, but they always
start with 54 bits of zeroes.  Test the whole first byte.

Drooids/babeld,boutier/babeld,sudomesh/babeld,dtaht/babeld-shortrtt-metrics,woniullb/babeld,wlanslovenija/babeld,jech/babeld,tcatm/babeld,Gwendocg/babeldToS,wlanslovenija/babeld,Gwendocg/babeldToS,jech/babeld