This replaces the old test-app for echo with separate client and server
minimal versions.
The autobahn test script is made more autonomous and tests both
client and server.
1) Remove the whole ah rxbuf and put things on to the wsi buflist
This eliminates the whole detachability thing based on ah rxbuf
state... ah can always be detached.
2) Remove h2 scratch and put it on the wsi buflist
3) Remove preamble_rx and use the wsi buflist
This was used in the case adopted sockets had already been read.
Basically there are now only three forced service scenarios
- something in buflist (and not in state LRS_DEFERRING_ACTION)
- tls layer has buffered rx
- extension has buffered rx
This is a net removal of around 400 lines of special-casing.
For h1 / ws, a combination of removing POLLIN wait and
stashing any unused rx lets us immediately respond to
rx flow control requests in a simple and effective way,
because the tcp socket is the stream.
But for muxed protocols like h2, that technique cannot
be used because we cannot silence the whole bundle of
streams because one can't handle any more rx dynamically.
There are control frames and content for other streams
serialized inbetween the flow controlled stream content.
We have no choice but to read to so we can see the other
things. Therefore for muxed protocols like h2 and spdy,
rx flow control boils down to tx credit manipulation
on individual streams to staunch the flow at the peer.
However that requires a round trip to take effect, any
transmitted packets that were in flight before the tx credit
reduction arrives at the remote peer are still going to come
and have to be dealt with by adding them to the stash.
This patch introduces lws_buflist scatter-gather type
buffer management for rxflow handling, so we can append
buffer segments in a linked-list to handle whatever rx
is unavoidably in flight on a stream that is trying to
assert rx flow control.
