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3 (C) 2011, 2012 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_stream_lib.h
23 * @brief stream handling using mesh API
24 * @author Sree Harsha Totakura
27 #ifndef GNUNET_STREAM_LIB_H
28 #define GNUNET_STREAM_LIB_H
38 #include "gnunet_util_lib.h"
39 #include "gnunet_mesh_service.h"
44 enum GNUNET_STREAM_Status
47 * All previous read/write operations are successfully done
52 * A timeout occured while reading/writing the stream
54 GNUNET_STREAM_TIMEOUT = 1,
57 * Other side has shutdown the socket for this type of operation
60 GNUNET_STREAM_SHUTDOWN = 2,
63 * A serious error occured while operating on this stream
65 GNUNET_STREAM_SYSERR = 3,
68 * An error resulted in an unusable stream
74 * Opaque handler for stream
76 struct GNUNET_STREAM_Socket;
79 * Functions of this type will be called when a stream is established
81 * @param cls the closure from GNUNET_STREAM_open
82 * @param socket socket to use to communicate with the other side (read/write)
84 typedef void (*GNUNET_STREAM_OpenCallback) (void *cls,
85 struct GNUNET_STREAM_Socket *socket);
89 * Options for the stream.
91 enum GNUNET_STREAM_Option
94 * End of the option list.
96 GNUNET_STREAM_OPTION_END = 0,
99 * Option to set the initial retransmission timeout (when do we retransmit
100 * a packet that did not yield an acknowledgement for the first time?).
101 * Repeated retransmissions will then use an exponential back-off.
102 * Takes a 'struct GNUNET_TIME_Relative' as the only argument. A value
103 * of '0' means to use the round-trip time (plus a tiny grace period);
104 * this is also the default.
106 GNUNET_STREAM_OPTION_INITIAL_RETRANSMIT_TIMEOUT,
109 * Option to set the write sequence number. Takes a uint32_t as parameter
110 * to set the value of the write sequence number
112 GNUNET_STREAM_OPTION_TESTING_SET_WRITE_SEQUENCE_NUMBER,
115 * Listen socket timeout in milliseconds
117 GNUNET_STREAM_OPTION_LISTEN_TIMEOUT
122 * Tries to open a stream to the target peer
124 * @param cfg configuration to use
125 * @param target the target peer to which the stream has to be opened
126 * @param app_port the application port number which uniquely identifies this
128 * @param open_cb this function will be called after stream has be established
129 * @param open_cb_cls the closure for open_cb
130 * @param ... options to the stream, terminated by GNUNET_STREAM_OPTION_END
131 * @return if successful it returns the stream socket; NULL if stream cannot be
134 struct GNUNET_STREAM_Socket *
135 GNUNET_STREAM_open (const struct GNUNET_CONFIGURATION_Handle *cfg,
136 const struct GNUNET_PeerIdentity *target,
137 GNUNET_MESH_ApplicationType app_port,
138 GNUNET_STREAM_OpenCallback open_cb,
144 * Handle for shutdown
146 struct GNUNET_STREAM_ShutdownHandle;
150 * Completion callback for shutdown
152 * @param cls the closure from GNUNET_STREAM_shutdown call
153 * @param operation the operation that was shutdown (SHUT_RD, SHUT_WR,
156 typedef void (*GNUNET_STREAM_ShutdownCompletion) (void *cls,
161 * Shutdown the stream for reading or writing (similar to man 2 shutdown).
163 * @param socket the stream socket
164 * @param operation SHUT_RD, SHUT_WR or SHUT_RDWR
165 * @param completion_cb the callback that will be called upon successful
166 * shutdown of given operation
167 * @param completion_cls the closure for the completion callback
168 * @return the shutdown handle; NULL in case of any error
170 struct GNUNET_STREAM_ShutdownHandle *
171 GNUNET_STREAM_shutdown (struct GNUNET_STREAM_Socket *socket,
173 GNUNET_STREAM_ShutdownCompletion completion_cb,
174 void *completion_cls);
178 * Cancels a pending shutdown
180 * @param handle the shutdown handle returned from GNUNET_STREAM_shutdown
183 GNUNET_STREAM_shutdown_cancel (struct GNUNET_STREAM_ShutdownHandle *handle);
187 * Closes the stream and frees the associated state. The stream should be
188 * shutdown before closing.
190 * @param socket the stream socket
193 GNUNET_STREAM_close (struct GNUNET_STREAM_Socket *socket);
197 * Functions of this type are called upon new stream connection from other peers
199 * @param cls the closure from GNUNET_STREAM_listen
200 * @param socket the socket representing the stream; NULL on binding error
201 * @param initiator the identity of the peer who wants to establish a stream
202 * with us; NULL on binding error
203 * @return GNUNET_OK to keep the socket open, GNUNET_SYSERR to close the
204 * stream (the socket will be invalid after the call)
206 typedef int (*GNUNET_STREAM_ListenCallback) (void *cls,
207 struct GNUNET_STREAM_Socket *socket,
209 GNUNET_PeerIdentity *initiator);
213 * A socket for listening.
215 struct GNUNET_STREAM_ListenSocket;
218 * Listens for stream connections for a specific application ports
220 * @param cfg the configuration to use
222 * @param app_port the application port for which new streams will be
223 * accepted. If another stream is listening on the same port the
224 * listen_cb will be called to signal binding error and the returned
225 * ListenSocket will be invalidated.
227 * @param listen_cb this function will be called when a peer tries to establish
229 * @param listen_cb_cls closure for listen_cb
230 * @param ... options to the stream, terminated by GNUNET_STREAM_OPTION_END
231 * @return listen socket, NULL for any error
233 struct GNUNET_STREAM_ListenSocket *
234 GNUNET_STREAM_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
235 GNUNET_MESH_ApplicationType app_port,
236 GNUNET_STREAM_ListenCallback listen_cb,
242 * Closes the listen socket
244 * @param lsocket the listen socket
247 GNUNET_STREAM_listen_close (struct GNUNET_STREAM_ListenSocket *lsocket);
251 * Functions of this signature are called whenever writing operations
252 * on a stream are executed
254 * @param cls the closure from GNUNET_STREAM_write
255 * @param status the status of the stream at the time this function is called
256 * @param size the number of bytes written
258 typedef void (*GNUNET_STREAM_CompletionContinuation) (void *cls,
259 enum GNUNET_STREAM_Status
265 * Handle to cancel IO write operations.
267 struct GNUNET_STREAM_IOWriteHandle;
271 * Handle to cancel IO read operations.
273 struct GNUNET_STREAM_IOReadHandle;
276 * Tries to write the given data to the stream. The maximum size of data that
277 * can be written as part of a write operation is (64 * (64000 - sizeof (struct
278 * GNUNET_STREAM_DataMessage))). If size is greater than this it is not an API
279 * violation, however only the said number of maximum bytes will be written.
281 * @param socket the socket representing a stream
282 * @param data the data buffer from where the data is written into the stream
283 * @param size the number of bytes to be written from the data buffer
284 * @param timeout the timeout period
285 * @param write_cont the function to call upon writing some bytes into the
287 * @param write_cont_cls the closure
289 * @return handle to cancel the operation; if a previous write is pending or
290 * the stream has been shutdown for this operation then write_cont is
291 * immediately called and NULL is returned.
293 struct GNUNET_STREAM_IOWriteHandle *
294 GNUNET_STREAM_write (struct GNUNET_STREAM_Socket *socket,
297 struct GNUNET_TIME_Relative timeout,
298 GNUNET_STREAM_CompletionContinuation write_cont,
299 void *write_cont_cls);
303 * Functions of this signature are called whenever data is available from the
306 * @param cls the closure from GNUNET_STREAM_read
307 * @param status the status of the stream at the time this function is called
308 * @param data traffic from the other side
309 * @param size the number of bytes available in data read; will be 0 on timeout
310 * @return number of bytes of processed from 'data' (any data remaining should be
311 * given to the next time the read processor is called).
313 typedef size_t (*GNUNET_STREAM_DataProcessor) (void *cls,
314 enum GNUNET_STREAM_Status status,
320 * Tries to read data from the stream.
322 * @param socket the socket representing a stream
323 * @param timeout the timeout period
324 * @param proc function to call with data (once only)
325 * @param proc_cls the closure for proc
327 * @return handle to cancel the operation; if the stream has been shutdown for
328 * this type of opeartion then the DataProcessor is immediately
329 * called with GNUNET_STREAM_SHUTDOWN as status and NULL if returned
331 struct GNUNET_STREAM_IOReadHandle *
332 GNUNET_STREAM_read (struct GNUNET_STREAM_Socket *socket,
333 struct GNUNET_TIME_Relative timeout,
334 GNUNET_STREAM_DataProcessor proc,
339 * Cancels pending write operation. Also cancels packet retransmissions which
340 * may have resulted otherwise.
342 * CAUTION: Normally a write operation is considered successful if the data
343 * given to it is sent and acknowledged by the receiver. As data is divided
344 * into packets, it is possible that not all packets are received by the
345 * receiver. Any missing packets are then retransmitted till the receiver
346 * acknowledges all packets or until a timeout . During this scenario if the
347 * write operation is cancelled all such retransmissions are also
348 * cancelled. This may leave the receiver's receive buffer incompletely filled
349 * as some missing packets are never retransmitted. So this operation should be
350 * used before shutting down transmission from our side or before closing the
353 * @param ioh handle to operation to cancel
356 GNUNET_STREAM_io_write_cancel (struct GNUNET_STREAM_IOWriteHandle *iowh);
360 * Cancel pending read operation.
362 * @param ioh handle to operation to cancel
365 GNUNET_STREAM_io_read_cancel (struct GNUNET_STREAM_IOReadHandle *iorh);
375 #endif /* STREAM_PROTOCOL_H */