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3 Copyright (C) 2009-2014 Christian Grothoff (and other contributing authors)
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21 * @file include/gnunet_core_service.h
22 * @brief core service; this is the main API for encrypted P2P
24 * @author Christian Grothoff
25 * @defgroup core encrypted direct communication between peers
28 #ifndef GNUNET_CORE_SERVICE_H
29 #define GNUNET_CORE_SERVICE_H
34 #if 0 /* keep Emacsens' auto-indent happy */
39 #include "gnunet_util_lib.h"
40 #include "gnunet_transport_service.h"
43 * Version number of GNUnet-core API.
45 #define GNUNET_CORE_VERSION 0x00000001
50 enum GNUNET_CORE_Priority
54 * Lowest priority, i.e. background traffic (i.e. fs)
56 GNUNET_CORE_PRIO_BACKGROUND = 0,
59 * Normal traffic (i.e. cadet/dv relay, DHT)
61 GNUNET_CORE_PRIO_BEST_EFFORT = 1,
64 * Urgent traffic (local peer, i.e. conversation).
66 GNUNET_CORE_PRIO_URGENT = 2,
69 * Highest priority, control traffic (i.e. NSE, Core/Cadet KX).
71 GNUNET_CORE_PRIO_CRITICAL_CONTROL = 3
78 * Opaque handle to the service.
80 struct GNUNET_CORE_Handle;
84 * Method called whenever a given peer connects.
87 * @param peer peer identity this notification is about
90 (*GNUNET_CORE_ConnectEventHandler) (void *cls,
91 const struct GNUNET_PeerIdentity *peer);
95 * Method called whenever a peer disconnects.
98 * @param peer peer identity this notification is about
101 (*GNUNET_CORE_DisconnectEventHandler) (void *cls,
102 const struct GNUNET_PeerIdentity *peer);
106 * Functions with this signature are called whenever a message is
107 * received or transmitted.
109 * @param cls closure (set from #GNUNET_CORE_connect)
110 * @param peer the other peer involved (sender or receiver, NULL
111 * for loopback messages where we are both sender and receiver)
112 * @param message the actual message
113 * @return #GNUNET_OK to keep the connection open,
114 * #GNUNET_SYSERR to close connection to the peer (signal serious error)
117 (*GNUNET_CORE_MessageCallback) (void *cls,
118 const struct GNUNET_PeerIdentity *other,
119 const struct GNUNET_MessageHeader *message);
123 * Message handler. Each struct specifies how to handle on particular
124 * type of message received.
126 struct GNUNET_CORE_MessageHandler
129 * Function to call for messages of @e type.
131 GNUNET_CORE_MessageCallback callback;
134 * Type of the message this handler covers.
139 * Expected size of messages of this type. Use 0 for variable-size.
140 * If non-zero, messages of the given type will be discarded if they
141 * do not have the right size.
143 uint16_t expected_size;
149 * Function called after #GNUNET_CORE_connect has succeeded (or failed
150 * for good). Note that the private key of the peer is intentionally
151 * not exposed here; if you need it, your process should try to read
152 * the private key file directly (which should work if you are
153 * authorized...). Implementations of this function must not call
154 * #GNUNET_CORE_disconnect (other than by scheduling a new task to
158 * @param my_identity ID of this peer, NULL if we failed
161 (*GNUNET_CORE_StartupCallback) (void *cls,
162 const struct GNUNET_PeerIdentity *my_identity);
166 * Connect to the core service. Note that the connection may complete
167 * (or fail) asynchronously. This function primarily causes the given
168 * callback notification functions to be invoked whenever the
169 * specified event happens. The maximum number of queued
170 * notifications (queue length) is per client; the queue is shared
171 * across all types of notifications. So a slow client that registers
172 * for @a outbound_notify also risks missing @a inbound_notify messages.
173 * Certain events (such as connect/disconnect notifications) are not
174 * subject to queue size limitations.
176 * @param cfg configuration to use
177 * @param cls closure for the various callbacks that follow (including handlers in the handlers array)
178 * @param init callback to call once we have successfully
179 * connected to the core service
180 * @param connects function to call on peer connect, can be NULL
181 * @param disconnects function to call on peer disconnect / timeout, can be NULL
182 * @param inbound_notify function to call for all inbound messages, can be NULL
183 * note that the core is allowed to drop notifications about inbound
184 * messages if the client does not process them fast enough (for this
185 * notification type, a bounded queue is used)
186 * @param inbound_hdr_only set to #GNUNET_YES if @a inbound_notify will only read the
187 * `struct GNUNET_MessageHeader` and hence we do not need to give it the full message;
188 * can be used to improve efficiency, ignored if inbound_notify is NULL
189 * note that the core is allowed to drop notifications about inbound
190 * messages if the client does not process them fast enough (for this
191 * notification type, a bounded queue is used)
192 * @param outbound_notify function to call for all outbound messages, can be NULL;
193 * note that the core is allowed to drop notifications about outbound
194 * messages if the client does not process them fast enough (for this
195 * notification type, a bounded queue is used)
196 * @param outbound_hdr_only set to #GNUNET_YES if @a outbound_notify will only read the
197 * `struct GNUNET_MessageHeader` and hence we do not need to give it the full message
198 * can be used to improve efficiency, ignored if outbound_notify is NULL
199 * note that the core is allowed to drop notifications about outbound
200 * messages if the client does not process them fast enough (for this
201 * notification type, a bounded queue is used)
202 * @param handlers callbacks for messages we care about, NULL-terminated
203 * note that the core is allowed to drop notifications about inbound
204 * messages if the client does not process them fast enough (for this
205 * notification type, a bounded queue is used)
206 * @return handle to the core service (only useful for disconnect until @a init is called),
207 * NULL on error (in this case, init is never called)
209 struct GNUNET_CORE_Handle *
210 GNUNET_CORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
212 GNUNET_CORE_StartupCallback init,
213 GNUNET_CORE_ConnectEventHandler connects,
214 GNUNET_CORE_DisconnectEventHandler disconnects,
215 GNUNET_CORE_MessageCallback inbound_notify,
216 int inbound_hdr_only,
217 GNUNET_CORE_MessageCallback outbound_notify,
218 int outbound_hdr_only,
219 const struct GNUNET_CORE_MessageHandler *handlers);
223 * Disconnect from the core service. This function can only
224 * be called *after* all pending #GNUNET_CORE_notify_transmit_ready
225 * requests have been explicitly cancelled.
227 * @param handle connection to core to disconnect
230 GNUNET_CORE_disconnect (struct GNUNET_CORE_Handle *handle);
234 * Handle for a transmission request.
236 struct GNUNET_CORE_TransmitHandle;
240 * Ask the core to call @a notify once it is ready to transmit the
241 * given number of bytes to the specified @a target. Must only be
242 * called after a connection to the respective peer has been
243 * established (and the client has been informed about this). You may
244 * have one request of this type pending for each connected peer at
245 * any time. If a peer disconnects, the application MUST call
246 * #GNUNET_CORE_notify_transmit_ready_cancel() on the respective
247 * transmission request, if one such request is pending.
249 * @param handle connection to core service
250 * @param cork is corking allowed for this transmission?
251 * @param priority how important is the message?
252 * @param maxdelay how long can the message wait? Only effective if @a cork is #GNUNET_YES
253 * @param target who should receive the message, never NULL (can be this peer's identity for loopback)
254 * @param notify_size how many bytes of buffer space does @a notify want?
255 * @param notify function to call when buffer space is available;
256 * will be called with NULL on timeout; clients MUST cancel
257 * all pending transmission requests DURING the disconnect
259 * @param notify_cls closure for @a notify
260 * @return non-NULL if the notify callback was queued,
261 * NULL if we can not even queue the request (request already pending);
262 * if NULL is returned, @a notify will NOT be called.
264 struct GNUNET_CORE_TransmitHandle *
265 GNUNET_CORE_notify_transmit_ready (struct GNUNET_CORE_Handle *handle,
267 enum GNUNET_CORE_Priority priority,
268 struct GNUNET_TIME_Relative maxdelay,
269 const struct GNUNET_PeerIdentity *target,
271 GNUNET_CONNECTION_TransmitReadyNotify notify,
276 * Cancel the specified transmission-ready notification.
278 * @param th handle that was returned by "notify_transmit_ready".
281 GNUNET_CORE_notify_transmit_ready_cancel (struct GNUNET_CORE_TransmitHandle *th);
285 * Handle to a CORE monitoring operation.
287 struct GNUNET_CORE_MonitorHandle;
291 * State machine for our P2P encryption handshake. Everyone starts in
292 * #GNUNET_CORE_KX_STATE_DOWN, if we receive the other peer's key
293 * (other peer initiated) we start in state
294 * #GNUNET_CORE_KX_STATE_KEY_RECEIVED (since we will immediately send
295 * our own); otherwise we start in #GNUNET_CORE_KX_STATE_KEY_SENT. If
296 * we get back a PONG from within either state, we move up to
297 * #GNUNET_CORE_KX_STATE_UP (the PONG will always be sent back
298 * encrypted with the key we sent to the other peer). Eventually,
299 * we will try to rekey, for this we will enter
300 * #GNUNET_CORE_KX_STATE_REKEY_SENT until the rekey operation is
301 * confirmed by a PONG from the other peer.
303 enum GNUNET_CORE_KxState
308 GNUNET_CORE_KX_STATE_DOWN,
311 * We've sent our session key.
313 GNUNET_CORE_KX_STATE_KEY_SENT,
316 * We've received the other peers session key.
318 GNUNET_CORE_KX_STATE_KEY_RECEIVED,
321 * The other peer has confirmed our session key + PING with a PONG
322 * message encrypted with his session key (which we got). Key
325 GNUNET_CORE_KX_STATE_UP,
328 * We're rekeying (or had a timeout), so we have sent the other peer
329 * our new ephemeral key, but we did not get a matching PONG yet.
330 * This is equivalent to being #GNUNET_CORE_KX_STATE_KEY_RECEIVED,
331 * except that the session is marked as 'up' with sessions (as we
332 * don't want to drop and re-establish P2P connections simply due to
335 GNUNET_CORE_KX_STATE_REKEY_SENT,
338 * Last state of a KX (when it is being terminated). Set
339 * just before CORE frees the internal state for this peer.
341 GNUNET_CORE_KX_PEER_DISCONNECT,
344 * This is not a state in a peer's state machine, but a special
345 * value used with the #GNUNET_CORE_MonitorCallback to indicate
346 * that we finished the initial iteration over the peers.
348 GNUNET_CORE_KX_ITERATION_FINISHED,
351 * This is not a state in a peer's state machine, but a special
352 * value used with the #GNUNET_CORE_MonitorCallback to indicate
353 * that we lost the connection to the CORE service (and will try
354 * to reconnect). If this happens, most likely the CORE service
355 * crashed and thus all connection state should be assumed lost.
357 GNUNET_CORE_KX_CORE_DISCONNECT
363 * Function called by the monitor callback whenever
364 * a peer's connection status changes.
367 * @param pid identity of the peer this update is about
368 * @param state current key exchange state of the peer
369 * @param timeout when does the current state expire
372 (*GNUNET_CORE_MonitorCallback)(void *cls,
373 const struct GNUNET_PeerIdentity *pid,
374 enum GNUNET_CORE_KxState state,
375 struct GNUNET_TIME_Absolute timeout);
379 * Monitor connectivity and KX status of all peers known to CORE.
380 * Calls @a peer_cb with the current status for each connected peer,
381 * and then once with NULL to indicate that all peers that are
382 * currently active have been handled. After that, the iteration
383 * continues until it is cancelled. Normal users of the CORE API are
384 * not expected to use this function. It is different in that it
385 * truly lists all connections (including those where the KX is in
386 * progress), not just those relevant to the application. This
387 * function is used by special applications for diagnostics.
389 * @param cfg configuration handle
390 * @param peer_cb function to call with the peer information
391 * @param peer_cb_cls closure for @a peer_cb
392 * @return NULL on error
394 struct GNUNET_CORE_MonitorHandle *
395 GNUNET_CORE_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
396 GNUNET_CORE_MonitorCallback peer_cb,
401 * Stop monitoring CORE activity.
403 * @param mh monitor to stop
406 GNUNET_CORE_monitor_stop (struct GNUNET_CORE_MonitorHandle *mh);
410 * Check if the given peer is currently connected. This function is for special
411 * cirumstances (GNUNET_TESTBED uses it), normal users of the CORE API are
412 * expected to track which peers are connected based on the connect/disconnect
413 * callbacks from #GNUNET_CORE_connect. This function is NOT part of the
414 * 'versioned', 'official' API. This function returns
415 * synchronously after looking in the CORE API cache.
417 * @param h the core handle
418 * @param pid the identity of the peer to check if it has been connected to us
419 * @return #GNUNET_YES if the peer is connected to us; #GNUNET_NO if not
422 GNUNET_CORE_is_peer_connected_sync (const struct GNUNET_CORE_Handle *h,
423 const struct GNUNET_PeerIdentity *pid);
427 * Create a message queue for sending messages to a peer with CORE.
428 * Messages may only be queued with #GNUNET_MQ_send once the init callback has
429 * been called for the given handle.
430 * There must only be one queue per peer for each core handle.
431 * The message queue can only be used to transmit messages,
432 * not to receive them.
434 * @param h the core handle
435 * @param target the target peer for this queue, may not be NULL
436 * @return a message queue for sending messages over the core handle
439 struct GNUNET_MQ_Handle *
440 GNUNET_CORE_mq_create (struct GNUNET_CORE_Handle *h,
441 const struct GNUNET_PeerIdentity *target);
444 #if 0 /* keep Emacsens' auto-indent happy */
451 /** @} */ /* end of group core */
453 /* ifndef GNUNET_CORE_SERVICE_H */
455 /* end of gnunet_core_service.h */