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
QuicSentEntropyManager()16 QuicSentEntropyManager::QuicSentEntropyManager()
17 : packets_entropy_hash_(0) {}
18
~QuicSentEntropyManager()19 QuicSentEntropyManager::~QuicSentEntropyManager() {}
20
RecordPacketEntropyHash(QuicPacketSequenceNumber sequence_number,QuicPacketEntropyHash entropy_hash)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
EntropyHash(QuicPacketSequenceNumber sequence_number) const36 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
IsValidEntropy(QuicPacketSequenceNumber sequence_number,const SequenceNumberSet & missing_packets,QuicPacketEntropyHash entropy_hash) const48 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
ClearEntropyBefore(QuicPacketSequenceNumber sequence_number)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