fw: abstract retransmission suppression logic
Consumer retransmission suppression logic of best-route v2 strategy
is abstracted into RetransmissionSuppression class, so that it can
be reused in other strategies.
refs #2377
Change-Id: I7de2c2d0e60c5ad3467e24283e9b03bd03f65bdc
diff --git a/daemon/fw/retransmission-suppression.cpp b/daemon/fw/retransmission-suppression.cpp
new file mode 100644
index 0000000..be1ff0b
--- /dev/null
+++ b/daemon/fw/retransmission-suppression.cpp
@@ -0,0 +1,59 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015, Regents of the University of California,
+ * Arizona Board of Regents,
+ * Colorado State University,
+ * University Pierre & Marie Curie, Sorbonne University,
+ * Washington University in St. Louis,
+ * Beijing Institute of Technology,
+ * The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "retransmission-suppression.hpp"
+
+namespace nfd {
+namespace fw {
+
+/// \todo don't use fixed interval; make it adaptive or use exponential back-off #1913
+const time::milliseconds RetransmissionSuppression::MIN_RETRANSMISSION_INTERVAL(100);
+
+RetransmissionSuppression::Result
+RetransmissionSuppression::decide(const Face& inFace, const Interest& interest,
+ const pit::Entry& pitEntry)
+{
+ bool isNewPitEntry = !pitEntry.hasUnexpiredOutRecords();
+ if (isNewPitEntry) {
+ return NEW;
+ }
+
+ // when was the last outgoing Interest?
+ const pit::OutRecordCollection& outRecords = pitEntry.getOutRecords();
+ pit::OutRecordCollection::const_iterator lastOutgoing = std::max_element(
+ outRecords.begin(), outRecords.end(),
+ [] (const pit::OutRecord& a, const pit::OutRecord& b) {
+ return a.getLastRenewed() < b.getLastRenewed();
+ });
+ BOOST_ASSERT(lastOutgoing != outRecords.end()); // otherwise it's new PIT entry
+
+ time::steady_clock::TimePoint now = time::steady_clock::now();
+ time::steady_clock::Duration sinceLastOutgoing = now - lastOutgoing->getLastRenewed();
+ bool shouldSuppress = sinceLastOutgoing < MIN_RETRANSMISSION_INTERVAL;
+ return shouldSuppress ? SUPPRESS : FORWARD;
+}
+
+} // namespace fw
+} // namespace nfd