Land recent QUIC changes.

net/quic/quic_packet_entropy_manager.cc

Index: net/quic/quic_packet_entropy_manager.cc
diff --git a/net/quic/quic_packet_entropy_manager.cc b/net/quic/quic_packet_entropy_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..35fb198237c65b520d123a76a7b43d02d29d60c6
--- /dev/null
+++ b/net/quic/quic_packet_entropy_manager.cc
@@ -0,0 +1,145 @@
+// Copyright (c) 2012 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_packet_entropy_manager.h"
+
+#include "base/logging.h"
+#include "net/base/linked_hash_map.h"
+
+using std::make_pair;
+using std::max;
+
+namespace net {
+
+QuicPacketEntropyManager::QuicPacketEntropyManager()
+    : sent_packets_entropy_hash_(0),
+      received_packets_entropy_hash_(0),
+      largest_received_sequence_number_(0) {}
+
+QuicPacketEntropyManager::~QuicPacketEntropyManager() {}
+
+void QuicPacketEntropyManager::RecordReceivedPacketEntropyHash(
+    QuicPacketSequenceNumber sequence_number,
+    QuicPacketEntropyHash entropy_hash) {
+  largest_received_sequence_number_ =
+      max<QuicPacketSequenceNumber>(largest_received_sequence_number_,
+                                    sequence_number);
+  received_packets_entropy_.insert(make_pair(sequence_number, entropy_hash));
+  received_packets_entropy_hash_ ^= entropy_hash;
+  DVLOG(2) << "setting cumulative received entropy hash to: "
+           << static_cast<int>(received_packets_entropy_hash_)
+           << " updated with sequence number " << sequence_number
+           << " entropy hash: " << static_cast<int>(entropy_hash);
+}
+
+void QuicPacketEntropyManager::RecordSentPacketEntropyHash(
+    QuicPacketSequenceNumber sequence_number,
+    QuicPacketEntropyHash entropy_hash) {
+  // TODO(satyamshekhar): Check this logic again when/if we enable packet
+  // reordering.
+  sent_packets_entropy_hash_ ^= entropy_hash;
+  sent_packets_entropy_.insert(
+      make_pair(sequence_number,
+                make_pair(entropy_hash, sent_packets_entropy_hash_)));
+  DVLOG(2) << "setting cumulative sent entropy hash to: "
+           << static_cast<int>(sent_packets_entropy_hash_)
+           << " updated with sequence number " << sequence_number
+           << " entropy hash: " << static_cast<int>(entropy_hash);
+}
+
+QuicPacketEntropyHash QuicPacketEntropyManager::ReceivedEntropyHash(
+    QuicPacketSequenceNumber sequence_number) const {
+  if (sequence_number == largest_received_sequence_number_) {
+    return received_packets_entropy_hash_;
+  }
+
+  ReceivedEntropyMap::const_iterator it =
+      received_packets_entropy_.upper_bound(sequence_number);
+  // When this map is empty we should only query entropy for
+  // |largest_received_sequence_number_|.
+  LOG_IF(WARNING, it != received_packets_entropy_.end())
+      << "largest_received: " << largest_received_sequence_number_
+      << " sequence_number: " << sequence_number;
+
+  // TODO(satyamshekhar): Make this O(1).
+  QuicPacketEntropyHash hash = received_packets_entropy_hash_;
+  for (; it != received_packets_entropy_.end(); ++it) {
+    hash ^= it->second;
+  }
+  return hash;
+}
+
+QuicPacketEntropyHash QuicPacketEntropyManager::SentEntropyHash(
+    QuicPacketSequenceNumber sequence_number) const {
+  SentEntropyMap::const_iterator it =
+      sent_packets_entropy_.find(sequence_number);
+  if (it == sent_packets_entropy_.end()) {
+    // Should only happen when we have not received ack for any packet.
+    DCHECK_EQ(0u, sequence_number);
+    return 0;
+  }
+  return it->second.second;
+}
+
+void QuicPacketEntropyManager::RecalculateReceivedEntropyHash(
+    QuicPacketSequenceNumber sequence_number,
+    QuicPacketEntropyHash entropy_hash) {
+  received_packets_entropy_hash_ = entropy_hash;
+  ReceivedEntropyMap::iterator it =
+      received_packets_entropy_.lower_bound(sequence_number);
+  // TODO(satyamshekhar): Make this O(1).
+  for (; it != received_packets_entropy_.end(); ++it) {
+    received_packets_entropy_hash_ ^= it->second;
+  }
+}
+
+bool QuicPacketEntropyManager::IsValidEntropy(
+    QuicPacketSequenceNumber sequence_number,
+    const SequenceNumberSet& missing_packets,
+    QuicPacketEntropyHash entropy_hash) const {
+  SentEntropyMap::const_iterator entropy_it =
+      sent_packets_entropy_.find(sequence_number);
+  if (entropy_it == sent_packets_entropy_.end()) {
+    DCHECK_EQ(0u, sequence_number);
+    // Close connection if something goes wrong.
+    return 0 == sequence_number;
+  }
+  QuicPacketEntropyHash expected_entropy_hash = entropy_it->second.second;
+  for (SequenceNumberSet::const_iterator it = missing_packets.begin();
+       it != missing_packets.end(); ++it) {
+    entropy_it = sent_packets_entropy_.find(*it);
+    DCHECK(entropy_it != sent_packets_entropy_.end());
+    expected_entropy_hash ^= entropy_it->second.first;
+  }
+  DLOG_IF(WARNING, entropy_hash != expected_entropy_hash)
+      << "Invalid entropy hash: " << static_cast<int>(entropy_hash)
+      << " expected entropy hash: " << static_cast<int>(expected_entropy_hash);
+  return entropy_hash == expected_entropy_hash;
+}
+
+void QuicPacketEntropyManager::ClearSentEntropyBefore(
+    QuicPacketSequenceNumber sequence_number) {
+  if (sent_packets_entropy_.empty()) {
+    return;
+  }
+  SentEntropyMap::iterator it = sent_packets_entropy_.begin();
+  while (it->first < sequence_number) {
+    sent_packets_entropy_.erase(it);
+    it = sent_packets_entropy_.begin();
+    DCHECK(it != sent_packets_entropy_.end());
+  }
+  DVLOG(2) << "Cleared entropy before: "
+           << sent_packets_entropy_.begin()->first;
+}
+
+void QuicPacketEntropyManager::ClearReceivedEntropyBefore(
+    QuicPacketSequenceNumber sequence_number) {
+  // This might clear the received_packets_entropy_ map if the current packet
+  // is peer_least_packet_awaiting_ack_ and it doesn't have entropy flag set.
+  received_packets_entropy_.erase(
+      received_packets_entropy_.begin(),
+      received_packets_entropy_.lower_bound(sequence_number));
+}
+
+}  // namespace net