| // Copyright 2013 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 |