Land Recent QUIC changes.

net/quic/quic_packet_entropy_manager.cc

-// 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;
-using std::min;
-
-namespace net {
-
-QuicPacketEntropyManager::QuicPacketEntropyManager()
-    : sent_packets_entropy_hash_(0),
-      received_packets_entropy_hash_(0),
-      largest_received_sequence_number_(0) {}
-
-QuicPacketEntropyManager::~QuicPacketEntropyManager() {}
-
-QuicPacketSequenceNumber
-QuicPacketEntropyManager::LargestReceivedSequenceNumber() const {
-  if (received_packets_entropy_.empty()) {
-    return 0;
-  }
-  return received_packets_entropy_.rbegin()->first;
-}
-
-void QuicPacketEntropyManager::RecordReceivedPacketEntropyHash(
-    QuicPacketSequenceNumber sequence_number,
-    QuicPacketEntropyHash entropy_hash) {
-  if (sequence_number < largest_received_sequence_number_) {
-    DLOG(INFO) << "Ignoring received packet entropy for sequence_number:"
-               << sequence_number << " less than largest_peer_sequence_number:"
-               << largest_received_sequence_number_;
-    return;
-  }
-  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 {
-  DCHECK_LE(sequence_number, LargestReceivedSequenceNumber());
-  DCHECK_GE(sequence_number, largest_received_sequence_number_);
-  if (sequence_number == LargestReceivedSequenceNumber()) {
-    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: " << LargestReceivedSequenceNumber()
-      << " 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 peer_least_unacked,
-    QuicPacketEntropyHash entropy_hash) {
-  DLOG_IF(WARNING, peer_least_unacked > LargestReceivedSequenceNumber())
-      << "Prematurely updating the entropy manager before registering the "
-      << "entropy of the containing packet creates a temporary inconsistency.";
-  if (peer_least_unacked < largest_received_sequence_number_) {
-    DLOG(INFO) << "Ignoring received peer_least_unacked:" << peer_least_unacked
-               << " less than largest_peer_sequence_number:"
-               << largest_received_sequence_number_;
-    return;
-  }
-  largest_received_sequence_number_ = peer_least_unacked;
-  received_packets_entropy_hash_ = entropy_hash;
-  ReceivedEntropyMap::iterator it =
-      received_packets_entropy_.lower_bound(peer_least_unacked);
-  // TODO(satyamshekhar): Make this O(1).
-  for (; it != received_packets_entropy_.end(); ++it) {
-    received_packets_entropy_hash_ ^= it->second;
-  }
-  // Discard entropies before least unacked.
-  received_packets_entropy_.erase(
-      received_packets_entropy_.begin(),
-      received_packets_entropy_.lower_bound(
-          min(peer_least_unacked, LargestReceivedSequenceNumber())));
-}
-
-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;
-}
-
-}  // namespace net