- Allocate zeroed memory in ether_resolvemulti() to prevent equal() from
comparing garbage and determining that two otherwise-equal sockaddr_dls
are different.
- Fill in all required fields of the sockaddr_dl
- Actually copy the multicast address into the sockaddr_dl when calling
if_addmulti()
- Don't claim that we don't have a way to resolve layer 3 addresses into
layer 2 addresses; use the ethernet way.