1// Copyright (c) 2012 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_CRYPTO_CRYPTO_FRAMER_H_
6#define NET_QUIC_CRYPTO_CRYPTO_FRAMER_H_
7
8#include <utility>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "base/logging.h"
13#include "base/strings/string_piece.h"
14#include "net/base/net_export.h"
15#include "net/quic/crypto/crypto_handshake_message.h"
16#include "net/quic/quic_protocol.h"
17
18namespace net {
19
20class CryptoFramer;
21class QuicData;
22class QuicDataReader;
23class QuicDataWriter;
24
25class NET_EXPORT_PRIVATE CryptoFramerVisitorInterface {
26 public:
27  virtual ~CryptoFramerVisitorInterface() {}
28
29  // Called if an error is detected.
30  virtual void OnError(CryptoFramer* framer) = 0;
31
32  // Called when a complete handshake message has been parsed.
33  virtual void OnHandshakeMessage(
34      const CryptoHandshakeMessage& message) = 0;
35};
36
37// A class for framing the crypto messages that are exchanged in a QUIC
38// session.
39class NET_EXPORT_PRIVATE CryptoFramer {
40 public:
41  CryptoFramer();
42
43  virtual ~CryptoFramer();
44
45  // ParseMessage parses exactly one message from the given StringPiece. If
46  // there is an error, the message is truncated, or the message has trailing
47  // garbage then NULL will be returned.
48  static CryptoHandshakeMessage* ParseMessage(base::StringPiece in);
49
50  // Set callbacks to be called from the framer.  A visitor must be set, or
51  // else the framer will crash.  It is acceptable for the visitor to do
52  // nothing.  If this is called multiple times, only the last visitor
53  // will be used.  |visitor| will be owned by the framer.
54  void set_visitor(CryptoFramerVisitorInterface* visitor) {
55    visitor_ = visitor;
56  }
57
58  QuicErrorCode error() const { return error_; }
59
60  // Processes input data, which must be delivered in order. Returns
61  // false if there was an error, and true otherwise.
62  bool ProcessInput(base::StringPiece input);
63
64  // Returns the number of bytes of buffered input data remaining to be
65  // parsed.
66  size_t InputBytesRemaining() const { return buffer_.length(); }
67
68  // Returns a new QuicData owned by the caller that contains a serialized
69  // |message|, or NULL if there was an error.
70  static QuicData* ConstructHandshakeMessage(
71      const CryptoHandshakeMessage& message);
72
73 private:
74  // Clears per-message state.  Does not clear the visitor.
75  void Clear();
76
77  // Process does does the work of |ProcessInput|, but returns an error code,
78  // doesn't set error_ and doesn't call |visitor_->OnError()|.
79  QuicErrorCode Process(base::StringPiece input);
80
81  static bool WritePadTag(QuicDataWriter* writer,
82                          size_t pad_length,
83                          uint32* end_offset);
84
85  // Represents the current state of the parsing state machine.
86  enum CryptoFramerState {
87    STATE_READING_TAG,
88    STATE_READING_NUM_ENTRIES,
89    STATE_READING_TAGS_AND_LENGTHS,
90    STATE_READING_VALUES
91  };
92
93  // Visitor to invoke when messages are parsed.
94  CryptoFramerVisitorInterface* visitor_;
95  // Last error.
96  QuicErrorCode error_;
97  // Remaining unparsed data.
98  std::string buffer_;
99  // Current state of the parsing.
100  CryptoFramerState state_;
101  // The message currently being parsed.
102  CryptoHandshakeMessage message_;
103  // Number of entires in the message currently being parsed.
104  uint16 num_entries_;
105  // tags_and_lengths_ contains the tags that are currently being parsed and
106  // their lengths.
107  std::vector<std::pair<QuicTag, size_t> > tags_and_lengths_;
108  // Cumulative length of all values in the message currently being parsed.
109  size_t values_len_;
110};
111
112}  // namespace net
113
114#endif  // NET_QUIC_CRYPTO_CRYPTO_FRAMER_H_
115