From f69527bb1467bc2723e6c04753cbf560edcd8d5e Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Thu, 14 Jun 2012 11:59:14 -0400
Subject: [PATCH] Initial sketch of channel stream messages.

---
 ssh-channel.rkt | 59 ++++++++++++++++++++++++++++++++++++++++++++++++-
 ssh-session.rkt |  1 +
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/ssh-channel.rkt b/ssh-channel.rkt
index f38d536..443b7ec 100644
--- a/ssh-channel.rkt
+++ b/ssh-channel.rkt
@@ -9,7 +9,15 @@
 
 (require "os2-support.rkt")
 
-(provide (struct-out ssh-channel))
+(provide (struct-out ssh-channel)
+	 (struct-out channel-stream-credit)
+	 (struct-out channel-stream-data)
+	 (struct-out channel-stream-extended-data)
+	 (struct-out channel-stream-eof)
+	 (struct-out channel-stream-notify)
+	 (struct-out channel-stream-request)
+	 (struct-out channel-stream-ok)
+	 (struct-out channel-stream-fail))
 
 ;; A CloseState is one of
 ;; - 'neither, indicating that neither side has signalled closure
@@ -41,3 +49,52 @@
 		     close-state ;; CloseState covering CLOSE signals
 		     )
 	#:transparent)
+
+;; ChannelMessage = (channel-message ChannelStreamName ChannelMessageBody)
+;; Relates a message to a particular stream within a channel within a
+;; connection.
+(struct channel-message (stream-name body) #:prefab)
+
+;; ChannelStreamName = (channel-stream-name Boolean Boolean Any)
+;; Names a stream within a channel within a connection. Unique within
+;; a particular connection. If (inbound?) is true, this is the stream
+;; of packets from the remote peer to the local peer; if false, the
+;; reverse. If (locally-originated?) is true, then the local peer is
+;; the one that opened this channel, and the local peer is reponsible
+;; for choosing the (identifier) and ensuring that it is unique with
+;; respect to other locally-originated streams within this connection;
+;; if false, the remote peer opened the channel, and the (identifier)
+;; is chosen managed by the connection-control code.
+(struct channel-stream-name (inbound? locally-originated? identifier) #:prefab)
+
+;; A ChannelMessageBody is one of
+;; -- (channel-stream-credit NonNegativeInteger) **
+;;    Informs the publisher that it may transmit another (count)
+;;    bytes.
+;; -- (channel-stream-data Bytes)
+;;    Data intended for the subscriber.
+;; -- (channel-stream-extended-data Uint32 Bytes)
+;;    Extended data intended for the subscriber. The type code is one
+;;    of those defined in ssh-numbers.rkt; for example,
+;;    SSH_EXTENDED_DATA_STDERR.
+;; -- (channel-stream-eof)
+;;    Signals the end of the data stream. Notice that channel closure
+;;    is signalled with presence changes.
+;; -- (channel-stream-notify Bytes Bytes)
+;;    One-way notification of SSH_MSG_CHANNEL_REQUEST.
+;; -- (channel-stream-request Bytes Bytes)
+;;    RPC SSH_MSG_CHANNEL_REQUEST request.
+;; -- (channel-stream-ok) **
+;;    RPC SSH_MSG_CHANNEL_REQUEST reply.
+;; -- (channel-stream-fail) **
+;;    RPC SSH_MSG_CHANNEL_REQUEST error.
+;;
+;; Messages marked ** travel "upstream", from subscriber to publisher.
+(struct channel-stream-credit (count) #:prefab)
+(struct channel-stream-data (bytes) #:prefab)
+(struct channel-stream-extended-data (type bytes) #:prefab)
+(struct channel-stream-eof () #:prefab)
+(struct channel-stream-notify (type bytes) #:prefab)
+(struct channel-stream-request (type bytes) #:prefab)
+(struct channel-stream-ok () #:prefab)
+(struct channel-stream-fail () #:prefab)
diff --git a/ssh-session.rkt b/ssh-session.rkt
index b3021d9..831ac5d 100644
--- a/ssh-session.rkt
+++ b/ssh-session.rkt
@@ -14,6 +14,7 @@
 (require "ssh-message-types.rkt")
 (require "ssh-exceptions.rkt")
 (require "ssh-transport.rkt")
+(require "ssh-channel.rkt")
 
 (require "os2-support.rkt")