security: Add CertificateCache

Change-Id: If7008877e9956c4e8964c99feac7ba34685106d7
Refs: #3317
diff --git a/src/security/v2/certificate-cache.cpp b/src/security/v2/certificate-cache.cpp
new file mode 100644
index 0000000..b3b745d
--- /dev/null
+++ b/src/security/v2/certificate-cache.cpp
@@ -0,0 +1,110 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library 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 Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#include "certificate-cache.hpp"
+#include "util/logger.hpp"
+
+namespace ndn {
+namespace security {
+namespace v2 {
+
+NDN_LOG_INIT(ndn.security.v2.CertificateCache);
+
+const time::nanoseconds&
+CertificateCache::getDefaultLifetime()
+{
+  static time::nanoseconds lifetime = time::seconds(3600);
+  return lifetime;
+}
+
+CertificateCache::CertificateCache(const time::nanoseconds& maxLifetime)
+  : m_certsByTime(m_certs.get<0>())
+  , m_certsByName(m_certs.get<1>())
+  , m_maxLifetime(maxLifetime)
+{
+}
+
+void
+CertificateCache::insert(const Certificate& cert)
+{
+  time::system_clock::TimePoint notAfterTime = cert.getValidityPeriod().getPeriod().second;
+  time::system_clock::TimePoint now = time::system_clock::now();
+  if (notAfterTime < now) {
+    NDN_LOG_DEBUG("Not adding " << cert.getName() << ": already expired at " << time::toIsoString(notAfterTime));
+    return;
+  }
+
+  time::system_clock::TimePoint removalTime = std::min(notAfterTime, now + m_maxLifetime);
+  NDN_LOG_DEBUG("Adding " << cert.getName() << ", will remove in "
+                << time::duration_cast<time::seconds>(removalTime - now));
+  m_certs.insert(Entry(cert, removalTime));
+}
+
+const Certificate*
+CertificateCache::find(const Name& keyName)
+{
+  refresh();
+  if (keyName.size() > 0 && keyName[-1].isImplicitSha256Digest()) {
+    NDN_LOG_INFO("Certificate search using name with the implicit digest is not yet supported");
+  }
+  auto itr = m_certsByName.lower_bound(keyName);
+  if (itr == m_certsByName.end() || !keyName.isPrefixOf(itr->getCertName()))
+    return nullptr;
+  return &itr->cert;
+}
+
+const Certificate*
+CertificateCache::find(const Interest& interest)
+{
+  if (interest.getChildSelector() >= 0) {
+    NDN_LOG_DEBUG("Certificate search using ChildSelector is not supported, search as if selector not specified");
+  }
+  if (interest.getName().size() > 0 && interest.getName()[-1].isImplicitSha256Digest()) {
+    NDN_LOG_INFO("Certificate search using name with the implicit digest is not yet supported");
+  }
+  refresh();
+
+  for (auto i = m_certsByName.lower_bound(interest.getName());
+       i != m_certsByName.end() && interest.getName().isPrefixOf(i->getCertName());
+       ++i) {
+    const auto& cert = i->cert;
+    if (interest.matchesData(cert)) {
+      return &cert;
+    }
+  }
+  return nullptr;
+}
+
+void
+CertificateCache::refresh()
+{
+  time::system_clock::TimePoint now = time::system_clock::now();
+
+  auto cIt = m_certsByTime.begin();
+  while (cIt != m_certsByTime.end() && cIt->removalTime < now) {
+    m_certsByTime.erase(cIt);
+    cIt = m_certsByTime.begin();
+  }
+}
+
+} // namespace v2
+} // namespace security
+} // namespace ndn