apps: Solving a serious bug #33 in ndn::ConsumerWindow
In certain cases, the number of in-flight packets was maintained in a
wrong way, creating inconsistencies and incorrect decision on when to
send out a new Interests. That is, the number of in-flight
packets could be non-zero, while there were no outstanding packets at all.
Thanks to Cheng Yi for the bug discovery
diff --git a/apps/ndn-consumer-window.cc b/apps/ndn-consumer-window.cc
index 7e8325d..a2e29b3 100644
--- a/apps/ndn-consumer-window.cc
+++ b/apps/ndn-consumer-window.cc
@@ -151,8 +151,6 @@
Simulator::Remove (m_sendEvent);
}
- // NS_LOG_DEBUG ("Window: " << m_window << ", InFlight: " << m_inFlight);
- m_inFlight++;
m_sendEvent = Simulator::ScheduleNow (&Consumer::SendPacket, this);
}
}
@@ -208,5 +206,13 @@
Consumer::OnTimeout (sequenceNumber);
}
+void
+ConsumerWindow::WillSendOutInterest (uint32_t sequenceNumber)
+{
+ m_inFlight ++;
+ Consumer::WillSendOutInterest (sequenceNumber);
+}
+
+
} // namespace ndn
} // namespace ns3
diff --git a/apps/ndn-consumer-window.h b/apps/ndn-consumer-window.h
index df79fb3..2057123 100644
--- a/apps/ndn-consumer-window.h
+++ b/apps/ndn-consumer-window.h
@@ -59,6 +59,9 @@
virtual void
OnTimeout (uint32_t sequenceNumber);
+ virtual void
+ WillSendOutInterest (uint32_t sequenceNumber);
+
protected:
/**
* \brief Constructs the Interest packet and sends it using a callback to the underlying NDN protocol
diff --git a/apps/ndn-consumer.cc b/apps/ndn-consumer.cc
index e579312..e5c2a44 100644
--- a/apps/ndn-consumer.cc
+++ b/apps/ndn-consumer.cc
@@ -214,23 +214,12 @@
packet->AddHeader (interestHeader);
NS_LOG_DEBUG ("Interest packet size: " << packet->GetSize ());
- NS_LOG_DEBUG ("Trying to add " << seq << " with " << Simulator::Now () << ". already " << m_seqTimeouts.size () << " items");
-
- m_seqTimeouts.insert (SeqTimeout (seq, Simulator::Now ()));
- m_seqFullDelay.insert (SeqTimeout (seq, Simulator::Now ()));
-
- m_seqLastDelay.erase (seq);
- m_seqLastDelay.insert (SeqTimeout (seq, Simulator::Now ()));
-
- m_seqRetxCounts[seq] ++;
-
- m_transmittedInterests (&interestHeader, this, m_face);
-
- m_rtt->SentSeq (SequenceNumber32 (seq), 1);
+ WillSendOutInterest (seq);
FwHopCountTag hopCountTag;
packet->AddPacketTag (hopCountTag);
+ m_transmittedInterests (&interestHeader, this, m_face);
m_protocolHandler (packet);
ScheduleNextPacket ();
@@ -324,5 +313,22 @@
ScheduleNextPacket ();
}
+void
+Consumer::WillSendOutInterest (uint32_t sequenceNumber)
+{
+ NS_LOG_DEBUG ("Trying to add " << sequenceNumber << " with " << Simulator::Now () << ". already " << m_seqTimeouts.size () << " items");
+
+ m_seqTimeouts.insert (SeqTimeout (sequenceNumber, Simulator::Now ()));
+ m_seqFullDelay.insert (SeqTimeout (sequenceNumber, Simulator::Now ()));
+
+ m_seqLastDelay.erase (sequenceNumber);
+ m_seqLastDelay.insert (SeqTimeout (sequenceNumber, Simulator::Now ()));
+
+ m_seqRetxCounts[sequenceNumber] ++;
+
+ m_rtt->SentSeq (SequenceNumber32 (sequenceNumber), 1);
+}
+
+
} // namespace ndn
} // namespace ns3
diff --git a/apps/ndn-consumer.h b/apps/ndn-consumer.h
index b748c2a..7dd4cdc 100644
--- a/apps/ndn-consumer.h
+++ b/apps/ndn-consumer.h
@@ -80,6 +80,16 @@
void
SendPacket ();
+ /**
+ * @brief An event that is fired just before an Interest packet is actually send out (send is inevitable)
+ *
+ * The reason for "before" even is that in certain cases (when it is possible to satisfy from the local cache),
+ * the send call will immediately return data, and if "after" even was used, this after would be called after
+ * all processing of incoming data, potentially producing unexpected results.
+ */
+ virtual void
+ WillSendOutInterest (uint32_t sequenceNumber);
+
protected:
// from App
virtual void