open bidder how to decode ip

gistfile1.txt

This field is indeed a little nasty, for parsing it check the documentation from the protobuf:

  // The first 3 bytes of the IP address in network byte order for IPv4, or the
  // first 6 bytes for IPv6.  Note that the number and position of the bytes
  // included from IPv6 addresses may change later.

This means you must first check if the size is 3 or 6 bytes, then depending on the size you can get the raw bytes and create the partial IP of the correct type. The last octet is not provided because Ad Exchange removes this information for privacy reasons.