NFD

NDN hub discovery procedure

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1. Add multicast face, issue interest for ``/local/ndn/udp``

    *   if data returned, configure face to the hub and finish auto-config

    *   auto-configured face is remembered using creating a "fake" route to ``/autoconf`` prefix

2. If previous step failed, issue the following DNS query using dig command 

        dig +search +short +cmd +tries=2 +ndots=10 _nfd._udp srv

    *   if valid data returned, get the first returned data, configure face, and finish auto-config

    *   auto-configured face is remembered using creating a "fake" route to /autoconf prefix

3. If previous steps failed:

    *   Obtain name of the default certificate configured for the user

    *   Try to extract site-specific part from the certificate name (TBD).  If failed, abort auto-configuration step.

    *   Append ``_homehub._autoconf.named-data.net.`` postfix to the site-specific DNSified name, e.g.

            alex.ucla.edu._homehub._autoconf.named-data.net.

    *   Issue a SRV dns query with ``_ndnx._udp`` prefix (not really necessary, but should do it for clarity)