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1 // Copyright 2014 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 // Handles packets for connection_ids in time wait state by discarding the | |
6 // packet and sending the clients a public reset packet with exponential | |
7 // backoff. | |
8 | |
9 #ifndef NET_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_ | |
10 #define NET_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_ | |
11 | |
12 #include <deque> | |
13 | |
14 #include "base/basictypes.h" | |
15 #include "base/containers/hash_tables.h" | |
16 #include "base/strings/string_piece.h" | |
17 #include "net/base/linked_hash_map.h" | |
18 #include "net/quic/quic_blocked_writer_interface.h" | |
19 #include "net/quic/quic_connection_helper.h" | |
20 #include "net/quic/quic_framer.h" | |
21 #include "net/quic/quic_packet_writer.h" | |
22 #include "net/quic/quic_protocol.h" | |
23 | |
24 namespace net { | |
25 | |
26 class ConnectionIdCleanUpAlarm; | |
27 class QuicServerSessionVisitor; | |
28 | |
29 namespace test { | |
30 class QuicTimeWaitListManagerPeer; | |
31 } // namespace test | |
32 | |
33 // Maintains a list of all connection_ids that have been recently closed. A | |
34 // connection_id lives in this state for kTimeWaitPeriod. All packets received | |
35 // for connection_ids in this state are handed over to the | |
36 // QuicTimeWaitListManager by the QuicDispatcher. Decides whether to send a | |
37 // public reset packet, a copy of the previously sent connection close packet, | |
38 // or nothing to the client which sent a packet with the connection_id in time | |
39 // wait state. After the connection_id expires its time wait period, a new | |
40 // connection/session will be created if a packet is received for this | |
41 // connection_id. | |
42 class QuicTimeWaitListManager : public QuicBlockedWriterInterface { | |
43 public: | |
44 // writer - the entity that writes to the socket. (Owned by the dispatcher) | |
45 // visitor - the entity that manages blocked writers. (The dispatcher) | |
46 // helper - used to run clean up alarms. (Owned by the owner of the server) | |
47 QuicTimeWaitListManager(QuicPacketWriter* writer, | |
48 QuicServerSessionVisitor* visitor, | |
49 QuicConnectionHelperInterface* helper, | |
50 const QuicVersionVector& supported_versions); | |
51 ~QuicTimeWaitListManager() override; | |
52 | |
53 // Adds the given connection_id to time wait state for kTimeWaitPeriod. | |
54 // Henceforth, any packet bearing this connection_id should not be processed | |
55 // while the connection_id remains in this list. If a non-nullptr | |
56 // |close_packet| is provided, it is sent again when packets are received for | |
57 // added connection_ids. If nullptr, a public reset packet is sent with the | |
58 // specified |version|. DCHECKs that connection_id is not already on the list. | |
59 void AddConnectionIdToTimeWait(QuicConnectionId connection_id, | |
60 QuicVersion version, | |
61 QuicEncryptedPacket* close_packet); // Owned. | |
62 | |
63 // Returns true if the connection_id is in time wait state, false otherwise. | |
64 // Packets received for this connection_id should not lead to creation of new | |
65 // QuicSessions. | |
66 bool IsConnectionIdInTimeWait(QuicConnectionId connection_id) const; | |
67 | |
68 // Called when a packet is received for a connection_id that is in time wait | |
69 // state. Sends a public reset packet to the client which sent this | |
70 // connection_id. Sending of the public reset packet is throttled by using | |
71 // exponential back off. DCHECKs for the connection_id to be in time wait | |
72 // state. virtual to override in tests. | |
73 virtual void ProcessPacket(const IPEndPoint& server_address, | |
74 const IPEndPoint& client_address, | |
75 QuicConnectionId connection_id, | |
76 QuicPacketSequenceNumber sequence_number, | |
77 const QuicEncryptedPacket& packet); | |
78 | |
79 // Called by the dispatcher when the underlying socket becomes writable again, | |
80 // since we might need to send pending public reset packets which we didn't | |
81 // send because the underlying socket was write blocked. | |
82 void OnCanWrite() override; | |
83 | |
84 // Used to delete connection_id entries that have outlived their time wait | |
85 // period. | |
86 void CleanUpOldConnectionIds(); | |
87 | |
88 // If necessary, trims the oldest connections from the time-wait list until | |
89 // the size is under the configured maximum. | |
90 void TrimTimeWaitListIfNeeded(); | |
91 | |
92 // Given a ConnectionId that exists in the time wait list, returns the | |
93 // QuicVersion associated with it. | |
94 QuicVersion GetQuicVersionFromConnectionId(QuicConnectionId connection_id); | |
95 | |
96 // The number of connections on the time-wait list. | |
97 size_t num_connections() const { return connection_id_map_.size(); } | |
98 | |
99 protected: | |
100 virtual QuicEncryptedPacket* BuildPublicReset( | |
101 const QuicPublicResetPacket& packet); | |
102 | |
103 private: | |
104 friend class test::QuicTimeWaitListManagerPeer; | |
105 | |
106 // Internal structure to store pending public reset packets. | |
107 class QueuedPacket; | |
108 | |
109 // Decides if a packet should be sent for this connection_id based on the | |
110 // number of received packets. | |
111 bool ShouldSendResponse(int received_packet_count); | |
112 | |
113 // Creates a public reset packet and sends it or queues it to be sent later. | |
114 void SendPublicReset(const IPEndPoint& server_address, | |
115 const IPEndPoint& client_address, | |
116 QuicConnectionId connection_id, | |
117 QuicPacketSequenceNumber rejected_sequence_number); | |
118 | |
119 // Either sends the packet and deletes it or makes pending_packets_queue_ the | |
120 // owner of the packet. | |
121 void SendOrQueuePacket(QueuedPacket* packet); | |
122 | |
123 // Sends the packet out. Returns true if the packet was successfully consumed. | |
124 // If the writer got blocked and did not buffer the packet, we'll need to keep | |
125 // the packet and retry sending. In case of all other errors we drop the | |
126 // packet. | |
127 bool WriteToWire(QueuedPacket* packet); | |
128 | |
129 // Register the alarm to wake up at appropriate time. | |
130 void SetConnectionIdCleanUpAlarm(); | |
131 | |
132 // Removes the oldest connection from the time-wait list if it was added prior | |
133 // to "expiration_time". To unconditionally remove the oldest connection, use | |
134 // a QuicTime::Delta:Infinity(). This function modifies the | |
135 // connection_id_map_. If you plan to call this function in a loop, any | |
136 // iterators that you hold before the call to this function may be invalid | |
137 // afterward. Returns true if the oldest connection was expired. Returns | |
138 // false if the map is empty or the oldest connection has not expired. | |
139 bool MaybeExpireOldestConnection(QuicTime expiration_time); | |
140 | |
141 // A map from a recently closed connection_id to the number of packets | |
142 // received after the termination of the connection bound to the | |
143 // connection_id. | |
144 struct ConnectionIdData { | |
145 ConnectionIdData(int num_packets_, | |
146 QuicVersion version_, | |
147 QuicTime time_added_, | |
148 QuicEncryptedPacket* close_packet) | |
149 : num_packets(num_packets_), | |
150 version(version_), | |
151 time_added(time_added_), | |
152 close_packet(close_packet) {} | |
153 int num_packets; | |
154 QuicVersion version; | |
155 QuicTime time_added; | |
156 QuicEncryptedPacket* close_packet; | |
157 }; | |
158 | |
159 // linked_hash_map allows lookup by ConnectionId and traversal in add order. | |
160 typedef linked_hash_map<QuicConnectionId, ConnectionIdData> ConnectionIdMap; | |
161 ConnectionIdMap connection_id_map_; | |
162 | |
163 // Pending public reset packets that need to be sent out to the client | |
164 // when we are given a chance to write by the dispatcher. | |
165 std::deque<QueuedPacket*> pending_packets_queue_; | |
166 | |
167 // Used to schedule alarms to delete old connection_ids which have been in the | |
168 // list for too long. | |
169 QuicConnectionHelperInterface* helper_; | |
170 | |
171 // Time period for which connection_ids should remain in time wait state. | |
172 const QuicTime::Delta kTimeWaitPeriod_; | |
173 | |
174 // Alarm registered with the connection helper to clean up connection_ids that | |
175 // have | |
176 // out lived their duration in time wait state. | |
177 scoped_ptr<QuicAlarm> connection_id_clean_up_alarm_; | |
178 | |
179 // Interface that writes given buffer to the socket. | |
180 QuicPacketWriter* writer_; | |
181 | |
182 // Interface that manages blocked writers. | |
183 QuicServerSessionVisitor* visitor_; | |
184 | |
185 DISALLOW_COPY_AND_ASSIGN(QuicTimeWaitListManager); | |
186 }; | |
187 | |
188 } // namespace net | |
189 | |
190 #endif // NET_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_ | |
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