relnote: Add a new class QuicBufferedPacketStore which is not in use yet.

net/quic/quic_buffered_packet_store.cc

+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/quic/quic_buffered_packet_store.h"
+
+#include <list>
+
+#include "base/stl_util.h"
+
+namespace net {
+
+typedef QuicBufferedPacketStore::BufferedPacket BufferedPacket;
+typedef QuicBufferedPacketStore::EnqueuePacketResult EnqueuePacketResult;
+typedef QuicBufferedPacketStore::BufferedPacketList BufferedPacketList;
+
+// Max number of connections this store can keep track.
+static const size_t kDefaultMaxConnectionsInStore = 100;
+
+namespace {
+
+// This alarm removes expired entries in map each time this alarm fires.
+class ConnectionExpireAlarm : public QuicAlarm::Delegate {
+ public:
+  explicit ConnectionExpireAlarm(QuicBufferedPacketStore* store)
+      : connection_store_(store) {}
+
+  void OnAlarm() override { connection_store_->OnExpirationTimeout(); }
+
+  // Disallow copy and asign.
+  ConnectionExpireAlarm(const ConnectionExpireAlarm&) = delete;
+  ConnectionExpireAlarm& operator=(const ConnectionExpireAlarm&) = delete;
+
+ private:
+  QuicBufferedPacketStore* connection_store_;
+};
+
+}  // namespace
+
+BufferedPacket::BufferedPacket(std::unique_ptr<QuicEncryptedPacket> packet,
+                               IPEndPoint server_address,
+                               IPEndPoint client_address)
+    : packet(std::move(packet)),
+      server_address(server_address),
+      client_address(client_address) {}
+
+BufferedPacket::BufferedPacket(BufferedPacket&& other) = default;
+
+BufferedPacket& BufferedPacket::operator=(BufferedPacket&& other) = default;
+
+BufferedPacket::~BufferedPacket() {}
+
+BufferedPacketList::BufferedPacketList() : creation_time(QuicTime::Zero()) {}
+
+BufferedPacketList::BufferedPacketList(BufferedPacketList&& other) = default;
+
+BufferedPacketList& BufferedPacketList::operator=(BufferedPacketList&& other) =
+    default;
+
+BufferedPacketList::~BufferedPacketList() {}
+
+QuicBufferedPacketStore::QuicBufferedPacketStore(
+    VisitorInterface* visitor,
+    QuicClock* clock,
+    QuicAlarmFactory* alarm_factory)
+    : connection_life_span_(
+          QuicTime::Delta::FromSeconds(kInitialIdleTimeoutSecs)),
+      visitor_(visitor),
+      clock_(clock),
+      expiration_alarm_(
+          alarm_factory->CreateAlarm(new ConnectionExpireAlarm(this))) {}
+
+QuicBufferedPacketStore::~QuicBufferedPacketStore() {}
+
+EnqueuePacketResult QuicBufferedPacketStore::EnqueuePacket(
+    QuicConnectionId connection_id,
+    const QuicEncryptedPacket& packet,
+    IPEndPoint server_address,
+    IPEndPoint client_address) {
+  if (!ContainsKey(undecryptable_packets_, connection_id) &&
+      undecryptable_packets_.size() >= kDefaultMaxConnectionsInStore) {
+    // Drop the packet if store can't keep track of more connections.
+    return TOO_MANY_CONNECTIONS;
+  } else if (!ContainsKey(undecryptable_packets_, connection_id)) {
+    undecryptable_packets_.emplace(
+        std::make_pair(connection_id, BufferedPacketList()));
+  }
+  CHECK(ContainsKey(undecryptable_packets_, connection_id));
+  BufferedPacketList& queue =
+      undecryptable_packets_.find(connection_id)->second;
+
+  if (queue.buffered_packets.size() >= kDefaultMaxUndecryptablePackets) {
+    // If there are kMaxBufferedPacketsPerConnection packets buffered up for
+    // this connection, drop the current packet.
+    return TOO_MANY_PACKETS;
+  }
+
+  if (queue.buffered_packets.empty()) {
+    // If this is the first packet arrived on a new connection, initialize the
+    // creation time.
+    queue.creation_time = clock_->ApproximateNow();
+  }
+
+  BufferedPacket new_entry(std::unique_ptr<QuicEncryptedPacket>(packet.Clone()),
+                           server_address, client_address);
+
+  queue.buffered_packets.push_back(std::move(new_entry));
+
+  if (!expiration_alarm_->IsSet()) {
+    expiration_alarm_->Set(clock_->ApproximateNow().Add(connection_life_span_));
+  }
+  return SUCCESS;
+}
+
+std::list<BufferedPacket> QuicBufferedPacketStore::DeliverPackets(
+    QuicConnectionId connection_id) {
+  std::list<BufferedPacket> packets_to_deliver;
+  auto it = undecryptable_packets_.find(connection_id);
+  if (it != undecryptable_packets_.end()) {
+    packets_to_deliver = std::move(it->second.buffered_packets);
+    undecryptable_packets_.erase(connection_id);
+  }
+  return packets_to_deliver;
+}
+
+void QuicBufferedPacketStore::OnExpirationTimeout() {
+  QuicTime expiration_time =
+      clock_->ApproximateNow().Subtract(connection_life_span_);
+  while (!undecryptable_packets_.empty()) {
+    auto& entry = undecryptable_packets_.front();
+    if (entry.second.creation_time > expiration_time) {
+      break;
+    }
+    visitor_->OnExpiredPackets(entry.first, std::move(entry.second));
+    undecryptable_packets_.erase(undecryptable_packets_.begin());
+  }
+  if (!undecryptable_packets_.empty()) {
+    expiration_alarm_->Set(clock_->ApproximateNow().Add(connection_life_span_));
+  }
+}
+
+}  // namespace net