Packets received from the "null" networks are packets received from tethering downstream interfaces. They should not be processed by all MdnsServiceTypeClients; instead they should be processed by the MdnsServiceTypeClient for the null network. Bug: 283708537 Test: atest (cherry picked from https://android-review.googlesource.com/q/commit:0ba206cbd168f5627da84911c0d7e5307e55c431) Merged-In: Ifef59eca7a24bdfe3650067445d2565869dfa852 Change-Id: Ifef59eca7a24bdfe3650067445d2565869dfa852