http2/http2-spec — pull request #454 by jpinner (2014-04-14 17:45:06+00:00)
Title: Move padding to the frame header.

This is a proof-of-concept to see what the spec would look like if Padding was defined as part of the common frame format instead of on each frame type.

Pros:
- It simplifies the frame validation (padding flags and length checks no longer depend on the frame type).
- It reduces the duplication in the spec.

Cons:
- It is a little more cumbersome to explain the length field as being the length of payload + padding + optional pad high / pad low.
- It requires adding text to some frame types to prohibit padding.

Changes:
- In most ways this is purely editorial, but of note is that the padding flags are now defined on all frame types. For example: previous receiving a PING frame with the PAD_HIGH bit set and the PAD_LOW bit cleared was completely valid and required to be processed, with this change, receiving a PING frame with either the H bit or L bit set must be treated as a connection error.

Thoughts and feedback welcome :)