1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "net/quic/quic_sent_entropy_manager.h" 6 7 #include "base/logging.h" 8 #include "net/base/linked_hash_map.h" 9 10 using std::make_pair; 11 using std::max; 12 using std::min; 13 14 namespace net { 15 16 QuicSentEntropyManager::QuicSentEntropyManager() 17 : packets_entropy_hash_(0) {} 18 19 QuicSentEntropyManager::~QuicSentEntropyManager() {} 20 21 void QuicSentEntropyManager::RecordPacketEntropyHash( 22 QuicPacketSequenceNumber sequence_number, 23 QuicPacketEntropyHash entropy_hash) { 24 // TODO(satyamshekhar): Check this logic again when/if we enable packet 25 // reordering. 26 packets_entropy_hash_ ^= entropy_hash; 27 packets_entropy_.insert( 28 make_pair(sequence_number, 29 make_pair(entropy_hash, packets_entropy_hash_))); 30 DVLOG(2) << "setting cumulative sent entropy hash to: " 31 << static_cast<int>(packets_entropy_hash_) 32 << " updated with sequence number " << sequence_number 33 << " entropy hash: " << static_cast<int>(entropy_hash); 34 } 35 36 QuicPacketEntropyHash QuicSentEntropyManager::EntropyHash( 37 QuicPacketSequenceNumber sequence_number) const { 38 SentEntropyMap::const_iterator it = 39 packets_entropy_.find(sequence_number); 40 if (it == packets_entropy_.end()) { 41 // Should only happen when we have not received ack for any packet. 42 DCHECK_EQ(0u, sequence_number); 43 return 0; 44 } 45 return it->second.second; 46 } 47 48 bool QuicSentEntropyManager::IsValidEntropy( 49 QuicPacketSequenceNumber sequence_number, 50 const SequenceNumberSet& missing_packets, 51 QuicPacketEntropyHash entropy_hash) const { 52 SentEntropyMap::const_iterator entropy_it = 53 packets_entropy_.find(sequence_number); 54 if (entropy_it == packets_entropy_.end()) { 55 DCHECK_EQ(0u, sequence_number); 56 // Close connection if something goes wrong. 57 return 0 == sequence_number; 58 } 59 QuicPacketEntropyHash expected_entropy_hash = entropy_it->second.second; 60 for (SequenceNumberSet::const_iterator it = missing_packets.begin(); 61 it != missing_packets.end(); ++it) { 62 entropy_it = packets_entropy_.find(*it); 63 DCHECK(entropy_it != packets_entropy_.end()); 64 expected_entropy_hash ^= entropy_it->second.first; 65 } 66 DLOG_IF(WARNING, entropy_hash != expected_entropy_hash) 67 << "Invalid entropy hash: " << static_cast<int>(entropy_hash) 68 << " expected entropy hash: " << static_cast<int>(expected_entropy_hash); 69 return entropy_hash == expected_entropy_hash; 70 } 71 72 void QuicSentEntropyManager::ClearEntropyBefore( 73 QuicPacketSequenceNumber sequence_number) { 74 if (packets_entropy_.empty()) { 75 return; 76 } 77 SentEntropyMap::iterator it = packets_entropy_.begin(); 78 while (it->first < sequence_number) { 79 packets_entropy_.erase(it); 80 it = packets_entropy_.begin(); 81 DCHECK(it != packets_entropy_.end()); 82 } 83 DVLOG(2) << "Cleared entropy before: " 84 << packets_entropy_.begin()->first; 85 } 86 87 } // namespace net 88
