Land Recent QUIC changes.

net/quic/quic_sent_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_sent_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 {
+
+QuicSentEntropyManager::QuicSentEntropyManager()
+    : packets_entropy_hash_(0) {}
+
+QuicSentEntropyManager::~QuicSentEntropyManager() {}
+
+void QuicSentEntropyManager::RecordPacketEntropyHash(
+    QuicPacketSequenceNumber sequence_number,
+    QuicPacketEntropyHash entropy_hash) {
+  // TODO(satyamshekhar): Check this logic again when/if we enable packet
+  // reordering.
+  packets_entropy_hash_ ^= entropy_hash;
+  packets_entropy_.insert(
+      make_pair(sequence_number,
+                make_pair(entropy_hash, packets_entropy_hash_)));
+  DVLOG(2) << "setting cumulative sent entropy hash to: "
+           << static_cast<int>(packets_entropy_hash_)
+           << " updated with sequence number " << sequence_number
+           << " entropy hash: " << static_cast<int>(entropy_hash);
+}
+
+QuicPacketEntropyHash QuicSentEntropyManager::EntropyHash(
+    QuicPacketSequenceNumber sequence_number) const {
+  SentEntropyMap::const_iterator it =
+      packets_entropy_.find(sequence_number);
+  if (it == 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;
+}
+
+bool QuicSentEntropyManager::IsValidEntropy(
+    QuicPacketSequenceNumber sequence_number,
+    const SequenceNumberSet& missing_packets,
+    QuicPacketEntropyHash entropy_hash) const {
+  SentEntropyMap::const_iterator entropy_it =
+      packets_entropy_.find(sequence_number);
+  if (entropy_it == 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 = packets_entropy_.find(*it);
+    DCHECK(entropy_it != 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 QuicSentEntropyManager::ClearEntropyBefore(
+    QuicPacketSequenceNumber sequence_number) {
+  if (packets_entropy_.empty()) {
+    return;
+  }
+  SentEntropyMap::iterator it = packets_entropy_.begin();
+  while (it->first < sequence_number) {
+    packets_entropy_.erase(it);
+    it = packets_entropy_.begin();
+    DCHECK(it != packets_entropy_.end());
+  }
+  DVLOG(2) << "Cleared entropy before: "
+           << packets_entropy_.begin()->first;
+}
+
+}  // namespace net