From 817859ce7658b30f8a4f76b6e260b4ed7ab147a4 Mon Sep 17 00:00:00 2001
From: michau-krakow <>
Date: Mon, 27 Feb 2023 13:39:28 +0100
Subject: [PATCH] Delay socket close so to re-send final ACK if needed.

Socket will be closed on the next retransmission timer expiry
---
 lib/protocol/reader.js           | 16 ++++++++++++----
 lib/streams/server/get-stream.js |  3 +++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/protocol/reader.js b/lib/protocol/reader.js
index a4c3a95..78d18aa 100644
--- a/lib/protocol/reader.js
+++ b/lib/protocol/reader.js
@@ -33,6 +33,10 @@ var Reader = module.exports = function (Super, args){
 		return a.block - b.block;
 	};
 	this._restransmitterStartFn = function (){
+		if (me._noMoreData) {
+			return me._close();
+		}
+
 		var block = me._blockToRetransmit ();
 		if (block > 0){
 			//Update the window and emit back to the client the data
@@ -157,7 +161,9 @@ Reader.prototype._notifyWindow = function (block){
 	
 	if (this._lastReceived){
 		this._noMoreData = true;
-		return this._close ();
+		// RFC 1350 section 6: On the other hand, delaying is encouraged. This means that the host sending the final
+		// ACK will wait for a while before terminating in order to retransmit the final ACK if it has been lost
+		return this.onFinished();
 	}
 	
 	this._pending = this._windowSize;
@@ -168,9 +174,11 @@ Reader.prototype._notifyWindow = function (block){
 };
 
 Reader.prototype._onData = function (message){
-	//DATA packet received after sending the last packet, the socket will be
-	//closed in the next tick
-	if (this._noMoreData) return;
+	//DATA packet received after sending the last packet, the socket is delay-closed so just ACK the client
+	if (this._noMoreData) {
+		this._sendAck(message.block);
+		return;
+	}
 
 	if (message.block === 0 && this._rolloverFix === 0){
 		//The server has rollovered to 0
diff --git a/lib/streams/server/get-stream.js b/lib/streams/server/get-stream.js
index e695742..a2e5693 100644
--- a/lib/streams/server/get-stream.js
+++ b/lib/streams/server/get-stream.js
@@ -91,6 +91,9 @@ GetStream.prototype._createReader = function (helper, message, globalOptions){
 		me.emit ("close");
 		me.emit ("abort");
 	};
+	this._reader.onFinished = function () {
+		me.push (null);	// Closes the stream, but not the Reader
+	};
 	this._reader.onClose = function (){
 		delete me._currFiles.put[me.file];
 		me.emit ("close");