cloudflare/cloudflared
Publicmirrored from https://github.com/cloudflare/cloudflaredAvailable
h2mux/muxedstream.go
289lines · modecode
| 1 | package h2mux |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "io" |
| 6 | "sync" |
| 7 | ) |
| 8 | |
| 9 | type ReadWriteLengther interface { |
| 10 | io.ReadWriter |
| 11 | Reset() |
| 12 | Len() int |
| 13 | } |
| 14 | |
| 15 | type ReadWriteClosedCloser interface { |
| 16 | io.ReadWriteCloser |
| 17 | Closed() bool |
| 18 | } |
| 19 | |
| 20 | type MuxedStream struct { |
| 21 | Headers []Header |
| 22 | |
| 23 | streamID uint32 |
| 24 | |
| 25 | responseHeadersReceived chan struct{} |
| 26 | |
| 27 | readBuffer ReadWriteClosedCloser |
| 28 | receiveWindow uint32 |
| 29 | // current window size limit. Exponentially increase it when it's exhausted |
| 30 | receiveWindowCurrentMax uint32 |
| 31 | // limit set in http2 spec. 2^31-1 |
| 32 | receiveWindowMax uint32 |
| 33 | |
| 34 | // nonzero if a WINDOW_UPDATE frame for a stream needs to be sent |
| 35 | windowUpdate uint32 |
| 36 | |
| 37 | writeLock sync.Mutex |
| 38 | // The zero value for Buffer is an empty buffer ready to use. |
| 39 | writeBuffer ReadWriteLengther |
| 40 | |
| 41 | sendWindow uint32 |
| 42 | |
| 43 | readyList *ReadyList |
| 44 | headersSent bool |
| 45 | writeHeaders []Header |
| 46 | // true if the write end of this stream has been closed |
| 47 | writeEOF bool |
| 48 | // true if we have sent EOF to the peer |
| 49 | sentEOF bool |
| 50 | // true if the peer sent us an EOF |
| 51 | receivedEOF bool |
| 52 | |
| 53 | // dictionary that was used to compress the stream |
| 54 | receivedUseDict bool |
| 55 | method string |
| 56 | contentType string |
| 57 | path string |
| 58 | dictionaries h2Dictionaries |
| 59 | readBufferLock sync.RWMutex |
| 60 | } |
| 61 | |
| 62 | func (s *MuxedStream) Read(p []byte) (n int, err error) { |
| 63 | if s.dictionaries.read != nil { |
| 64 | s.readBufferLock.RLock() |
| 65 | b := s.readBuffer |
| 66 | s.readBufferLock.RUnlock() |
| 67 | return b.Read(p) |
| 68 | } |
| 69 | return s.readBuffer.Read(p) |
| 70 | } |
| 71 | |
| 72 | func (s *MuxedStream) Write(p []byte) (n int, err error) { |
| 73 | ok := assignDictToStream(s, p) |
| 74 | if !ok { |
| 75 | s.writeLock.Lock() |
| 76 | } |
| 77 | defer s.writeLock.Unlock() |
| 78 | if s.writeEOF { |
| 79 | return 0, io.EOF |
| 80 | } |
| 81 | n, err = s.writeBuffer.Write(p) |
| 82 | if n != len(p) || err != nil { |
| 83 | return n, err |
| 84 | } |
| 85 | s.writeNotify() |
| 86 | return n, nil |
| 87 | } |
| 88 | |
| 89 | func (s *MuxedStream) Close() error { |
| 90 | // TUN-115: Close the write buffer before the read buffer. |
| 91 | // In the case of shutdown, read will not get new data, but the write buffer can still receive |
| 92 | // new data. Closing read before write allows application to race between a failed read and a |
| 93 | // successful write, even though this close should appear to be atomic. |
| 94 | // This can't happen the other way because reads may succeed after a failed write; if we read |
| 95 | // past EOF the application will block until we close the buffer. |
| 96 | err := s.CloseWrite() |
| 97 | if err != nil { |
| 98 | if s.CloseRead() == nil { |
| 99 | // don't bother the caller with errors if at least one close succeeded |
| 100 | return nil |
| 101 | } |
| 102 | return err |
| 103 | } |
| 104 | return s.CloseRead() |
| 105 | } |
| 106 | |
| 107 | func (s *MuxedStream) CloseRead() error { |
| 108 | return s.readBuffer.Close() |
| 109 | } |
| 110 | |
| 111 | func (s *MuxedStream) CloseWrite() error { |
| 112 | s.writeLock.Lock() |
| 113 | defer s.writeLock.Unlock() |
| 114 | if s.writeEOF { |
| 115 | return io.EOF |
| 116 | } |
| 117 | s.writeEOF = true |
| 118 | if c, ok := s.writeBuffer.(io.Closer); ok { |
| 119 | c.Close() |
| 120 | } |
| 121 | s.writeNotify() |
| 122 | return nil |
| 123 | } |
| 124 | |
| 125 | func (s *MuxedStream) WriteHeaders(headers []Header) error { |
| 126 | s.writeLock.Lock() |
| 127 | defer s.writeLock.Unlock() |
| 128 | if s.writeHeaders != nil { |
| 129 | return ErrStreamHeadersSent |
| 130 | } |
| 131 | |
| 132 | if s.dictionaries.write != nil { |
| 133 | dictWriter := s.dictionaries.write.getDictWriter(s, headers) |
| 134 | if dictWriter != nil { |
| 135 | s.writeBuffer = dictWriter |
| 136 | } |
| 137 | |
| 138 | } |
| 139 | |
| 140 | s.writeHeaders = headers |
| 141 | s.headersSent = false |
| 142 | s.writeNotify() |
| 143 | return nil |
| 144 | } |
| 145 | |
| 146 | func (s *MuxedStream) getReceiveWindow() uint32 { |
| 147 | s.writeLock.Lock() |
| 148 | defer s.writeLock.Unlock() |
| 149 | return s.receiveWindow |
| 150 | } |
| 151 | |
| 152 | func (s *MuxedStream) getSendWindow() uint32 { |
| 153 | s.writeLock.Lock() |
| 154 | defer s.writeLock.Unlock() |
| 155 | return s.sendWindow |
| 156 | } |
| 157 | |
| 158 | // writeNotify must happen while holding writeLock. |
| 159 | func (s *MuxedStream) writeNotify() { |
| 160 | s.readyList.Signal(s.streamID) |
| 161 | } |
| 162 | |
| 163 | // Call by muxreader when it gets a WindowUpdateFrame. This is an update of the peer's |
| 164 | // receive window (how much data we can send). |
| 165 | func (s *MuxedStream) replenishSendWindow(bytes uint32) { |
| 166 | s.writeLock.Lock() |
| 167 | s.sendWindow += bytes |
| 168 | s.writeNotify() |
| 169 | s.writeLock.Unlock() |
| 170 | } |
| 171 | |
| 172 | // Call by muxreader when it receives a data frame |
| 173 | func (s *MuxedStream) consumeReceiveWindow(bytes uint32) bool { |
| 174 | s.writeLock.Lock() |
| 175 | defer s.writeLock.Unlock() |
| 176 | // received data size is greater than receive window/buffer |
| 177 | if s.receiveWindow < bytes { |
| 178 | return false |
| 179 | } |
| 180 | s.receiveWindow -= bytes |
| 181 | if s.receiveWindow < s.receiveWindowCurrentMax/2 { |
| 182 | // exhausting client send window (how much data client can send) |
| 183 | if s.receiveWindowCurrentMax < s.receiveWindowMax { |
| 184 | s.receiveWindowCurrentMax <<= 1 |
| 185 | } |
| 186 | s.windowUpdate += s.receiveWindowCurrentMax - s.receiveWindow |
| 187 | s.writeNotify() |
| 188 | } |
| 189 | return true |
| 190 | } |
| 191 | |
| 192 | // receiveEOF should be called when the peer indicates no more data will be sent. |
| 193 | // Returns true if the socket is now closed (i.e. the write side is already closed). |
| 194 | func (s *MuxedStream) receiveEOF() (closed bool) { |
| 195 | s.writeLock.Lock() |
| 196 | defer s.writeLock.Unlock() |
| 197 | s.receivedEOF = true |
| 198 | s.CloseRead() |
| 199 | return s.writeEOF && s.writeBuffer.Len() == 0 |
| 200 | } |
| 201 | |
| 202 | func (s *MuxedStream) gotReceiveEOF() bool { |
| 203 | s.writeLock.Lock() |
| 204 | defer s.writeLock.Unlock() |
| 205 | return s.receivedEOF |
| 206 | } |
| 207 | |
| 208 | // MuxedStreamReader implements io.ReadCloser for the read end of the stream. |
| 209 | // This is useful for passing to functions that close the object after it is done reading, |
| 210 | // but you still want to be able to write data afterwards (e.g. http.Client). |
| 211 | type MuxedStreamReader struct { |
| 212 | *MuxedStream |
| 213 | } |
| 214 | |
| 215 | func (s MuxedStreamReader) Read(p []byte) (n int, err error) { |
| 216 | return s.MuxedStream.Read(p) |
| 217 | } |
| 218 | |
| 219 | func (s MuxedStreamReader) Close() error { |
| 220 | return s.MuxedStream.CloseRead() |
| 221 | } |
| 222 | |
| 223 | // streamChunk represents a chunk of data to be written. |
| 224 | type streamChunk struct { |
| 225 | streamID uint32 |
| 226 | // true if a HEADERS frame should be sent |
| 227 | sendHeaders bool |
| 228 | headers []Header |
| 229 | // nonzero if a WINDOW_UPDATE frame should be sent |
| 230 | windowUpdate uint32 |
| 231 | // true if data frames should be sent |
| 232 | sendData bool |
| 233 | eof bool |
| 234 | buffer bytes.Buffer |
| 235 | } |
| 236 | |
| 237 | // getChunk atomically extracts a chunk of data to be written by MuxWriter. |
| 238 | // The data returned will not exceed the send window for this stream. |
| 239 | func (s *MuxedStream) getChunk() *streamChunk { |
| 240 | s.writeLock.Lock() |
| 241 | defer s.writeLock.Unlock() |
| 242 | |
| 243 | chunk := &streamChunk{ |
| 244 | streamID: s.streamID, |
| 245 | sendHeaders: !s.headersSent, |
| 246 | headers: s.writeHeaders, |
| 247 | windowUpdate: s.windowUpdate, |
| 248 | sendData: !s.sentEOF, |
| 249 | eof: s.writeEOF && uint32(s.writeBuffer.Len()) <= s.sendWindow, |
| 250 | } |
| 251 | |
| 252 | // Copies at most s.sendWindow bytes |
| 253 | writeLen, _ := io.CopyN(&chunk.buffer, s.writeBuffer, int64(s.sendWindow)) |
| 254 | s.sendWindow -= uint32(writeLen) |
| 255 | s.receiveWindow += s.windowUpdate |
| 256 | s.windowUpdate = 0 |
| 257 | s.headersSent = true |
| 258 | |
| 259 | // if this chunk contains the end of the stream, close the stream now |
| 260 | if chunk.sendData && chunk.eof { |
| 261 | s.sentEOF = true |
| 262 | } |
| 263 | |
| 264 | return chunk |
| 265 | } |
| 266 | |
| 267 | func (c *streamChunk) sendHeadersFrame() bool { |
| 268 | return c.sendHeaders |
| 269 | } |
| 270 | |
| 271 | func (c *streamChunk) sendWindowUpdateFrame() bool { |
| 272 | return c.windowUpdate > 0 |
| 273 | } |
| 274 | |
| 275 | func (c *streamChunk) sendDataFrame() bool { |
| 276 | return c.sendData |
| 277 | } |
| 278 | |
| 279 | func (c *streamChunk) nextDataFrame(frameSize int) (payload []byte, endStream bool) { |
| 280 | payload = c.buffer.Next(frameSize) |
| 281 | if c.buffer.Len() == 0 { |
| 282 | // this is the last data frame in this chunk |
| 283 | c.sendData = false |
| 284 | if c.eof { |
| 285 | endStream = true |
| 286 | } |
| 287 | } |
| 288 | return |
| 289 | } |
| 290 | |