# HG changeset patch
# User Alexander Krotov <krotov@iitp.ru>
# Date 1455548367 -10800
#      Mon Feb 15 17:59:27 2016 +0300
# Node ID f117d17414e378b3ad81530c102bcd58d7eadf7c
# Parent  4f0dc872b81e213990ff4ed91a7e57e7f2c2f3e8
Fix BytesInFlight (bug #1783)

See https://tools.ietf.org/html/rfc4898#page-23

diff -r 4f0dc872b81e -r f117d17414e3 src/internet/model/tcp-socket-base.cc
--- a/src/internet/model/tcp-socket-base.cc	Thu Feb 11 21:59:47 2016 +0100
+++ b/src/internet/model/tcp-socket-base.cc	Mon Feb 15 17:59:27 2016 +0300
@@ -2544,7 +2544,9 @@
 TcpSocketBase::BytesInFlight () const
 {
   NS_LOG_FUNCTION (this);
-  return m_highTxMark.Get () - m_txBuffer->HeadSequence ();
+  uint32_t flightSize = m_nextTxSequence.Get () - m_txBuffer->HeadSequence ();
+  uint32_t duplicatesSize = m_dupAckCount * m_tcb->m_segmentSize;
+  return duplicatesSize > flightSize ? 0 : flightSize - duplicatesSize;
 }
 
 uint32_t
@@ -2869,9 +2871,6 @@
    * are not able to retransmit anything because of local congestion.
    */
 
-  m_nextTxSequence = m_txBuffer->HeadSequence (); // Restart from highest Ack
-  m_dupAckCount = 0;
-
   if (m_tcb->m_congState != TcpSocketState::CA_LOSS)
     {
       m_tcb->m_congState = TcpSocketState::CA_LOSS;
@@ -2879,6 +2878,9 @@
       m_tcb->m_cWnd = m_tcb->m_segmentSize;
     }
 
+  m_nextTxSequence = m_txBuffer->HeadSequence (); // Restart from highest Ack
+  m_dupAckCount = 0;
+
   NS_LOG_DEBUG ("RTO. Reset cwnd to " <<  m_tcb->m_cWnd << ", ssthresh to " <<
                 m_tcb->m_ssThresh << ", restart from seqnum " << m_nextTxSequence);
   DoRetransmit ();                          // Retransmit the packet