From 08585ec49568f6273f51526e40c108abb7480e4d Mon Sep 17 00:00:00 2001
From: Hans Nilsson <hans@erlang.org>
Date: Wed, 25 Nov 2015 15:55:13 +0100
Subject: ssh: added 'pending' in recv_window handling and limit sending

---
 lib/ssh/src/ssh_connect.hrl            |  3 +++
 lib/ssh/src/ssh_connection_handler.erl | 27 +++++++++++++++++++++------
 2 files changed, 24 insertions(+), 6 deletions(-)

(limited to 'lib/ssh/src')

diff --git a/lib/ssh/src/ssh_connect.hrl b/lib/ssh/src/ssh_connect.hrl
index 6db89c5d80..9f9f3de8fa 100644
--- a/lib/ssh/src/ssh_connect.hrl
+++ b/lib/ssh/src/ssh_connect.hrl
@@ -248,6 +248,9 @@
 	  local_id,           %% local channel id
 
 	  recv_window_size,
+	  recv_window_pending = 0, %% Sum of window size updates that has not
+	                           %% yet been sent. This limits the number
+	                           %% of sent update msgs.
 	  recv_packet_size,
 	  recv_close = false,
 
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 505c6eb181..68062209fc 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -731,13 +731,28 @@ handle_event({adjust_window, ChannelId, Bytes}, StateName,
 			#connection{channel_cache = Cache}} = State0) ->
     State =
 	case ssh_channel:cache_lookup(Cache, ChannelId) of
-	    #channel{recv_window_size = WinSize, remote_id = Id} = Channel ->
-		ssh_channel:cache_update(Cache, Channel#channel{recv_window_size =
-					       WinSize + Bytes}),
-		Msg = ssh_connection:channel_adjust_window_msg(Id, Bytes),
+	    #channel{recv_window_size = WinSize,
+		     recv_window_pending = Pending,
+		     recv_packet_size = PktSize} = Channel
+	      when (WinSize-Bytes) >= 2*PktSize ->
+		%% The peer can send at least two more *full* packet, no hurry.
+		ssh_channel:cache_update(Cache, 
+					 Channel#channel{recv_window_pending = Pending + Bytes}),
+		State0;
+
+	    #channel{recv_window_size = WinSize,
+		     recv_window_pending = Pending,
+		     remote_id = Id} = Channel ->
+		%% Now we have to update the window - we can't receive so many more pkts
+		ssh_channel:cache_update(Cache, 
+					 Channel#channel{recv_window_size =
+							     WinSize + Bytes + Pending,
+							 recv_window_pending = 0}),
+		Msg = ssh_connection:channel_adjust_window_msg(Id, Bytes + Pending),
 		send_replies([{connection_reply, Msg}], State0);
-	undefined ->
-	    State0
+
+	    undefined ->
+		State0
 	end,
     {next_state, StateName, next_packet(State)};
 
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