Bug 2796

Summary:	NSC TCP transmission flow control not working
Product:	ns-3	Reporter:	Tom Henderson <tomh>
Component:	nsc-tcp	Assignee:	Florian Westphal <fw-ns3>
Status:	RESOLVED FIXED
Severity:	normal	CC:	ns-bugs
Priority:	P3
Version:	unspecified
Hardware:	All
OS:	All
Attachments:	test program to reproduce the problem

Description Tom Henderson 2017-10-05 11:41:37 UTC

NscTcpSocketImpl::SendPendingData() will write to NSC using:
m_nscTcpSocket->send_data()

If the underlying NSC socket buffer becomes full, the return value of send_data() will indicate this and SendPendingData() will return false, and some data will be sitting in the staging buffer m_txBuffer.  Later, an NSCWakeup() may trigger the emptying of this buffer (since NSC may later have space), but Socket::NotifySend() is never called to unblock the application, and the TCP transfer will stall.

Comment 1 Tom Henderson 2017-10-05 13:25:04 UTC

Created attachment 2931 [details]
test program to reproduce the problem

Comment 2 Tom Henderson 2017-10-05 13:49:40 UTC

fixed in 13109:0f13cb543416