I think ever since commit 679fa90df last month, PuTTY has been
forgetting to free any of its outgoing packet structures after turning
them into their encrypted wire format. And apparently no users of the
development snapshots have noticed - including me!
sshbpp.h now defines a classoid that encapsulates both directions of
an SSH binary packet protocol - that is, a system for reading a
bufchain of incoming data and turning it into a stream of PktIn, and
another system for taking a PktOut and turning it into data on an
outgoing bufchain.
The state structure in each of those files contains everything that
used to be in the 'rdpkt2_state' structure and its friends, and also
quite a lot of bits and pieces like cipher and MAC states that used to
live in the main Ssh structure.
One minor effect of this layer separation is that I've had to extend
the packet dispatch table by one, because the BPP layer can no longer
directly trigger sending of SSH_MSG_UNIMPLEMENTED for a message too
short to have a type byte. Instead, I extend the PktIn type field to
use an out-of-range value to encode that, and the easiest way to make
that trigger an UNIMPLEMENTED message is to have the dispatch table
contain an entry for it.
(That's a system that may come in useful again - I was also wondering
about inventing a fake type code to indicate network EOF, so that that
could be propagated through the layers and be handled by whichever one
currently knew best how to respond.)
I've also moved the packet-censoring code into its own pair of files,
partly because I was going to want to do that anyway sooner or later,
and mostly because it's called from the BPP code, and the SSH-2
version in particular has to be called from both the main SSH-2 BPP
and the bare unencrypted protocol used for connection sharing. While I
was at it, I took the opportunity to merge the outgoing and incoming
censor functions, so that the parts that were common between them
(e.g. CHANNEL_DATA messages look the same in both directions) didn't
need to be repeated.
Simon Tatham