TODO

TODO for PCS

*) Eliminate the assumption that a TLV or LV always encodes its length
   in bytes. This is inconsistent with the definition of Field.

  *) Eliminate the assumption that a TLV always contains itself or
     indeed counts itself in its length, see below.

*) In IGMP, add a pointer to the type numbers:
    http://www.iana.org/assignments/igmp-type-numbers

   Think carefully about how to deal with the fact that at least
   6 different protocols use "igmp" as their encapsulation.
   Probably an IGMP "map" is best, as the header fields are often
   never referred to outside of their own context.

*) Fix the pretty-printing for TCP options.

*) Fix the lack of variable-width bounds in the PCS meta-language.

   At the moment, LengthValueFields and TypeLengthValueFields have
   no notion of a variable width, so they always encode and decode
   as fixed length fields. This makes it very difficult to capture
   most packet structures correctly in PCS.

*) Fix the IP4Connector so that it will work and can be reliably used
   instead of the PcapConnector. Without an ARP module, going straight
   to Ethernet is tedious, and doesn't even work for other link layers.

  *) Reimplement the IP-layer diagnostic tools to use the IP4Connector.

*) Come up with a fix for BPF loopback injection on FreeBSD and push the
   fix upstream.

*) Add many many more packets

*) Teach BPF and pcap how to request allmulti.