Lookup all the IGD (IP urn:schemas-upnp-org:service:WANIPConnection:1, or
PPP urn:schemas-upnp-org:service:WANPPPConnection:1) devices for a given
network interface.
The direct hits map contains those peers that reported to have the key (Number160) we were looking for including
its digest (size of the result set and its xored hashes).