ipv6: network byte order rx_address

Change-Id: If580b812f3295ee4d022933cb396c512bf25fedb
ipv6: 128-bit host addresses in fsstate.dat

Store IP addresses in 128-bit fields in the fsstate.dat file.
Use IPv4-mapped addresses to embed IPv4 values.

Change-Id: Ic63f8c77db5781cf7f7d57c2b6ce32314b4ede82