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 18 namespace net { 19 20 class CryptoFramer; 21 class QuicData; 22 class QuicDataReader; 23 class QuicDataWriter; 24 25 class 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. 39 class 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
