In the current test case unicast_v4, host one is router but it use if_bridge(4) to verify the reachability to CARP master. Well unfortunately if_bridge(4) brings the two CARP hosts into one broadcast domain, thus falsely report success with unusual ( undocumented ) setup, that both hosts in a same network, one in unicast mode but another one in multicast mode. That setup can not when they are in different network due to IPv4 multicast nature.
Fix that by propagating route via routed(8).
A bug in carp(4) happens to turn one host with peer address x.x.x.224 into multicast mode. Update to cover that case.
PR: 284872
MFC after: 3 days