OLD | NEW |
| (Empty) |
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 #ifndef NET_QUIC_PORT_SUGGESTER_H_ | |
6 #define NET_QUIC_PORT_SUGGESTER_H_ | |
7 | |
8 #include "base/basictypes.h" | |
9 #include "base/memory/ref_counted.h" | |
10 #include "base/sha1.h" | |
11 #include "net/base/net_export.h" | |
12 | |
13 namespace net { | |
14 | |
15 class HostPortPair; | |
16 | |
17 // We provide a pseudo-random number generator that is always seeded the same | |
18 // way for a given destination host-port pair. The generator is used to | |
19 // consistently suggest (for that host-port pair) an ephemeral source port, | |
20 // and hence increase the likelihood that a server's load balancer will direct | |
21 // a repeated connection to the same server (with QUIC, further increasing the | |
22 // chance of connection establishment with 0-RTT). | |
23 class NET_EXPORT_PRIVATE PortSuggester | |
24 : public base::RefCounted<PortSuggester> { | |
25 public: | |
26 PortSuggester(const HostPortPair& server, uint64 seed); | |
27 | |
28 // Generate a pseudo-random int in the inclusive range from |min| to |max|. | |
29 // Will (probably) return different numbers when called repeatedly. | |
30 int SuggestPort(int min, int max); | |
31 | |
32 uint32 call_count() const { return call_count_; } | |
33 int previous_suggestion() const; | |
34 | |
35 private: | |
36 friend class base::RefCounted<PortSuggester>; | |
37 | |
38 virtual ~PortSuggester() {} | |
39 | |
40 // We maintain the first 8 bytes of a hash as our seed_ state. | |
41 uint64 seed_; | |
42 uint32 call_count_; // Number of suggestions made. | |
43 int previous_suggestion_; | |
44 | |
45 DISALLOW_COPY_AND_ASSIGN(PortSuggester); | |
46 }; | |
47 | |
48 } // namespace net | |
49 | |
50 #endif // NET_QUIC_PORT_SUGGESTER_H_ | |
OLD | NEW |