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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_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_
6 #define NET_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_
7 
8 #include <string>
9 
10 #include "base/callback.h"
11 #include "base/memory/ref_counted.h"
12 #include "base/memory/scoped_ptr.h"
13 #include "base/memory/scoped_vector.h"
14 #include "net/websockets/websocket_frame_parser.h"
15 #include "net/websockets/websocket_stream.h"
16 
17 namespace net {
18 
19 class ClientSocketHandle;
20 class DrainableIOBuffer;
21 class GrowableIOBuffer;
22 class IOBufferWithSize;
23 struct WebSocketFrame;
24 struct WebSocketFrameChunk;
25 
26 // Implementation of WebSocketStream for non-multiplexed ws:// connections (or
27 // the physical side of a multiplexed ws:// connection).
28 class NET_EXPORT_PRIVATE WebSocketBasicStream : public WebSocketStream {
29  public:
30   typedef WebSocketMaskingKey (*WebSocketMaskingKeyGeneratorFunction)();
31 
32   // This class should not normally be constructed directly; see
33   // WebSocketStream::CreateAndConnectStream() and
34   // WebSocketBasicHandshakeStream::Upgrade().
35   WebSocketBasicStream(
36       scoped_ptr<ClientSocketHandle> connection,
37       const scoped_refptr<GrowableIOBuffer>& http_read_buffer,
38       const std::string& sub_protocol,
39       const std::string& extensions);
40 
41   // The destructor has to make sure the connection is closed when we finish so
42   // that it does not get returned to the pool.
43   virtual ~WebSocketBasicStream();
44 
45   // WebSocketStream implementation.
46   virtual int ReadFrames(ScopedVector<WebSocketFrame>* frames,
47                          const CompletionCallback& callback) OVERRIDE;
48 
49   virtual int WriteFrames(ScopedVector<WebSocketFrame>* frames,
50                           const CompletionCallback& callback) OVERRIDE;
51 
52   virtual void Close() OVERRIDE;
53 
54   virtual std::string GetSubProtocol() const OVERRIDE;
55 
56   virtual std::string GetExtensions() const OVERRIDE;
57 
58   ////////////////////////////////////////////////////////////////////////////
59   // Methods for testing only.
60 
61   static scoped_ptr<WebSocketBasicStream> CreateWebSocketBasicStreamForTesting(
62       scoped_ptr<ClientSocketHandle> connection,
63       const scoped_refptr<GrowableIOBuffer>& http_read_buffer,
64       const std::string& sub_protocol,
65       const std::string& extensions,
66       WebSocketMaskingKeyGeneratorFunction key_generator_function);
67 
68  private:
69   // Returns OK or calls |callback| when the |buffer| is fully drained or
70   // something has failed.
71   int WriteEverything(const scoped_refptr<DrainableIOBuffer>& buffer,
72                       const CompletionCallback& callback);
73 
74   // Wraps the |callback| to continue writing until everything has been written.
75   void OnWriteComplete(const scoped_refptr<DrainableIOBuffer>& buffer,
76                        const CompletionCallback& callback,
77                        int result);
78 
79   // Attempts to parse the output of a read as WebSocket frames. On success,
80   // returns OK and places the frame(s) in |frames|.
81   int HandleReadResult(int result, ScopedVector<WebSocketFrame>* frames);
82 
83   // Converts the chunks in |frame_chunks| into frames and writes them to
84   // |frames|. |frame_chunks| is destroyed in the process. Returns
85   // ERR_WS_PROTOCOL_ERROR if an invalid chunk was found. If one or more frames
86   // was added to |frames|, then returns OK, otherwise returns ERR_IO_PENDING.
87   int ConvertChunksToFrames(ScopedVector<WebSocketFrameChunk>* frame_chunks,
88                             ScopedVector<WebSocketFrame>* frames);
89 
90   // Converts a |chunk| to a |frame|. |*frame| should be NULL on entry to this
91   // method. If |chunk| is an incomplete control frame, or an empty middle
92   // frame, then |*frame| may still be NULL on exit. If an invalid control frame
93   // is found, returns ERR_WS_PROTOCOL_ERROR and the stream is no longer
94   // usable. Otherwise returns OK (even if frame is still NULL).
95   int ConvertChunkToFrame(scoped_ptr<WebSocketFrameChunk> chunk,
96                           scoped_ptr<WebSocketFrame>* frame);
97 
98   // Creates a frame based on the value of |is_final_chunk|, |data| and
99   // |current_frame_header_|. Clears |current_frame_header_| if |is_final_chunk|
100   // is true. |data| may be NULL if the frame has an empty payload. A frame in
101   // the middle of a message with no data is not useful; in this case the
102   // returned frame will be NULL. Otherwise, |current_frame_header_->opcode| is
103   // set to Continuation after use if it was Text or Binary, in accordance with
104   // WebSocket RFC6455 section 5.4.
105   scoped_ptr<WebSocketFrame> CreateFrame(
106       bool is_final_chunk,
107       const scoped_refptr<IOBufferWithSize>& data);
108 
109   // Adds |data_buffer| to the end of |incomplete_control_frame_body_|, applying
110   // bounds checks.
111   void AddToIncompleteControlFrameBody(
112       const scoped_refptr<IOBufferWithSize>& data_buffer);
113 
114   // Called when a read completes. Parses the result and (unless no complete
115   // header has been received) calls |callback|.
116   void OnReadComplete(ScopedVector<WebSocketFrame>* frames,
117                       const CompletionCallback& callback,
118                       int result);
119 
120   // Storage for pending reads. All active WebSockets spend all the time with a
121   // call to ReadFrames() pending, so there is no benefit in trying to share
122   // this between sockets.
123   scoped_refptr<IOBufferWithSize> read_buffer_;
124 
125   // The connection, wrapped in a ClientSocketHandle so that we can prevent it
126   // from being returned to the pool.
127   scoped_ptr<ClientSocketHandle> connection_;
128 
129   // Frame header for the frame currently being received. Only non-NULL while we
130   // are processing the frame. If the frame arrives in multiple chunks, it can
131   // remain non-NULL until additional chunks arrive. If the header of the frame
132   // was invalid, this is set to NULL, the channel is failed, and subsequent
133   // chunks of the same frame will be ignored.
134   scoped_ptr<WebSocketFrameHeader> current_frame_header_;
135 
136   // Although it should rarely happen in practice, a control frame can arrive
137   // broken into chunks. This variable provides storage for a partial control
138   // frame until the rest arrives. It will be NULL the rest of the time.
139   scoped_refptr<GrowableIOBuffer> incomplete_control_frame_body_;
140 
141   // Only used during handshake. Some data may be left in this buffer after the
142   // handshake, in which case it will be picked up during the first call to
143   // ReadFrames(). The type is GrowableIOBuffer for compatibility with
144   // net::HttpStreamParser, which is used to parse the handshake.
145   scoped_refptr<GrowableIOBuffer> http_read_buffer_;
146 
147   // This keeps the current parse state (including any incomplete headers) and
148   // parses frames.
149   WebSocketFrameParser parser_;
150 
151   // The negotated sub-protocol, or empty for none.
152   const std::string sub_protocol_;
153 
154   // The extensions negotiated with the remote server.
155   const std::string extensions_;
156 
157   // This can be overridden in tests to make the output deterministic. We don't
158   // use a Callback here because a function pointer is faster and good enough
159   // for our purposes.
160   WebSocketMaskingKeyGeneratorFunction generate_websocket_masking_key_;
161 };
162 
163 }  // namespace net
164 
165 #endif  // NET_WEBSOCKETS_WEBSOCKET_BASIC_STREAM_H_
166