From 89019eabf5b30e048cd6e4290d11611a954cd5b7 Mon Sep 17 00:00:00 2001
From: Adrian S Tam <adrian.sw.tam@gmail.com>
Date: Sat, 3 Dec 2011 14:02:19 -0500
Subject: [PATCH] Send ACK to some out-of-order packets (fixes bug 1112 and
 part of 1256)

---
 src/aodv/test/tcp-chain-test-9-0.pcap | Bin 19486 -> 19974 bytes
 src/internet/model/tcp-socket-base.cc |   5 +++++
 2 files changed, 5 insertions(+)

diff --git a/src/aodv/test/tcp-chain-test-9-0.pcap b/src/aodv/test/tcp-chain-test-9-0.pcap
index f2a57ed28876ce0a7190fa506fc42af8a567400b..12038ecd7cd6289d90b999eca4a2c8e6f2190b18 100644
GIT binary patch
delta 191
zcmbO?gRyN6;|3uYW}b(PlO6fw1q>Khtzu?iVBlbIWnj=?;GbN;Co%b)gAnrxpn^af
z>CHke8<?0S^_an`9Z*#Zz*S!ZDgdcI<OWpjzlsg4IsjF*AY3)~YBsRyBF{BUlMSp{
Zn13E*2kKDZN7Wz%*Rbsn`{acx;s6kzFs%Rp

delta 36
ucmV+<0NekDoB^Jg0k9H815qjilff1jli)W5v#Lar0<*S9umZE-N~{9*#SSw7

diff --git a/src/internet/model/tcp-socket-base.cc b/src/internet/model/tcp-socket-base.cc
index fa4ae37b8..3de68ae13 100644
--- a/src/internet/model/tcp-socket-base.cc
+++ b/src/internet/model/tcp-socket-base.cc
@@ -683,6 +683,11 @@ TcpSocketBase::DoForwardUp (Ptr<Packet> packet, Ipv4Header header, uint16_t port
                     ":" << tcpHeader.GetSequenceNumber () + packet->GetSize() <<
                     ") out of range [" << m_rxBuffer.NextRxSequence () << ":" <<
                     m_rxBuffer.MaxRxSequence () << ")");
+      // Acknowledgement should be sent for all unacceptable packets (RFC793, p.69)
+      if (m_state == ESTABLISHED && !(tcpHeader.GetFlags () & TcpHeader::RST))
+        {
+          SendEmptyPacket (TcpHeader::ACK);
+        }
       return;
     }