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3 Copyright (C) 2009-2017 GNUnet e.V.
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19 * @author Christian Grothoff
21 * @file include/gnunet_core_service.h
22 * Core service; the main API for encrypted P2P communications
24 * @defgroup core Core service
25 * Encrypted direct communication between peers
27 * @see [Documentation](https://gnunet.org/gnunet-core-subsystem)
31 #ifndef GNUNET_CORE_SERVICE_H
32 #define GNUNET_CORE_SERVICE_H
37 #if 0 /* keep Emacsens' auto-indent happy */
42 #include "gnunet_util_lib.h"
43 #include "gnunet_transport_service.h"
46 * Version number of GNUnet-core API.
48 #define GNUNET_CORE_VERSION 0x00000001
53 enum GNUNET_CORE_Priority
57 * Lowest priority, i.e. background traffic (i.e. fs)
59 GNUNET_CORE_PRIO_BACKGROUND = 0,
62 * Normal traffic (i.e. cadet/dv relay, DHT)
64 GNUNET_CORE_PRIO_BEST_EFFORT = 1,
67 * Urgent traffic (local peer, i.e. conversation).
69 GNUNET_CORE_PRIO_URGENT = 2,
72 * Highest priority, control traffic (i.e. NSE, Core/Cadet KX).
74 GNUNET_CORE_PRIO_CRITICAL_CONTROL = 3
81 * Opaque handle to the service.
83 struct GNUNET_CORE_Handle;
87 * Method called whenever a given peer connects.
90 * @param peer peer identity this notification is about
91 * @return closure associated with @a peer. given to mq callbacks and
92 * #GNUNET_CORE_DisconnectEventHandler
95 (*GNUNET_CORE_ConnectEventHandler) (void *cls,
96 const struct GNUNET_PeerIdentity *peer,
97 struct GNUNET_MQ_Handle *mq);
101 * Method called whenever a peer disconnects.
104 * @param peer peer identity this notification is about
105 * @param peer_cls closure associated with peer. given in
106 * #GNUNET_CORE_ConnectEventHandler
109 (*GNUNET_CORE_DisconnectEventHandler) (void *cls,
110 const struct GNUNET_PeerIdentity *peer,
115 * Function called after #GNUNET_CORE_connect has succeeded (or failed
116 * for good). Note that the private key of the peer is intentionally
117 * not exposed here; if you need it, your process should try to read
118 * the private key file directly (which should work if you are
119 * authorized...). Implementations of this function must not call
120 * #GNUNET_CORE_disconnect (other than by scheduling a new task to
124 * @param my_identity ID of this peer, NULL if we failed
127 (*GNUNET_CORE_StartupCallback) (void *cls,
128 const struct GNUNET_PeerIdentity *my_identity);
132 * Connect to the core service. Note that the connection may complete
133 * (or fail) asynchronously. This function primarily causes the given
134 * callback notification functions to be invoked whenever the
135 * specified event happens. The maximum number of queued
136 * notifications (queue length) is per client; the queue is shared
137 * across all types of notifications. So a slow client that registers
138 * for @a outbound_notify also risks missing @a inbound_notify messages.
139 * Certain events (such as connect/disconnect notifications) are not
140 * subject to queue size limitations.
142 * @param cfg configuration to use
143 * @param cls closure for the various callbacks that follow (including handlers in the handlers array)
144 * @param init callback to call once we have successfully
145 * connected to the core service
146 * @param connects function to call on peer connect, can be NULL
147 * @param disconnects function to call on peer disconnect / timeout, can be NULL
148 * @param handlers callbacks for messages we care about, NULL-terminated
149 * note that the core is allowed to drop notifications about inbound
150 * messages if the client does not process them fast enough (for this
151 * notification type, a bounded queue is used)
152 * @return handle to the core service (only useful for disconnect until @a init is called),
153 * NULL on error (in this case, init is never called)
155 struct GNUNET_CORE_Handle *
156 GNUNET_CORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
158 GNUNET_CORE_StartupCallback init,
159 GNUNET_CORE_ConnectEventHandler connects,
160 GNUNET_CORE_DisconnectEventHandler disconnects,
161 const struct GNUNET_MQ_MessageHandler *handlers);
165 * Disconnect from the core service.
167 * @param handle connection to core to disconnect
170 GNUNET_CORE_disconnect (struct GNUNET_CORE_Handle *handle);
174 * Inquire with CORE what options should be set for a message
175 * so that it is transmitted with the given @a priority and
176 * the given @a cork value.
178 * @param cork desired corking
179 * @param priority desired message priority
180 * @param[out] flags set to `flags` value for #GNUNET_MQ_set_options()
181 * @return `extra` argument to give to #GNUNET_MQ_set_options()
184 GNUNET_CORE_get_mq_options (int cork,
185 enum GNUNET_CORE_Priority priority,
190 * Obtain the message queue for a connected peer.
192 * @param h the core handle
193 * @param pid the identity of the peer
194 * @return NULL if @a pid is not connected
196 struct GNUNET_MQ_Handle *
197 GNUNET_CORE_get_mq (const struct GNUNET_CORE_Handle *h,
198 const struct GNUNET_PeerIdentity *pid);
202 * Handle to a CORE monitoring operation.
204 struct GNUNET_CORE_MonitorHandle;
208 * State machine for our P2P encryption handshake. Everyone starts in
209 * #GNUNET_CORE_KX_STATE_DOWN, if we receive the other peer's key
210 * (other peer initiated) we start in state
211 * #GNUNET_CORE_KX_STATE_KEY_RECEIVED (since we will immediately send
212 * our own); otherwise we start in #GNUNET_CORE_KX_STATE_KEY_SENT. If
213 * we get back a PONG from within either state, we move up to
214 * #GNUNET_CORE_KX_STATE_UP (the PONG will always be sent back
215 * encrypted with the key we sent to the other peer). Eventually,
216 * we will try to rekey, for this we will enter
217 * #GNUNET_CORE_KX_STATE_REKEY_SENT until the rekey operation is
218 * confirmed by a PONG from the other peer.
220 enum GNUNET_CORE_KxState
225 GNUNET_CORE_KX_STATE_DOWN = 0,
228 * We've sent our session key.
230 GNUNET_CORE_KX_STATE_KEY_SENT,
233 * We've received the other peers session key.
235 GNUNET_CORE_KX_STATE_KEY_RECEIVED,
238 * The other peer has confirmed our session key + PING with a PONG
239 * message encrypted with their session key (which we got). Key
242 GNUNET_CORE_KX_STATE_UP,
245 * We're rekeying (or had a timeout), so we have sent the other peer
246 * our new ephemeral key, but we did not get a matching PONG yet.
247 * This is equivalent to being #GNUNET_CORE_KX_STATE_KEY_RECEIVED,
248 * except that the session is marked as 'up' with sessions (as we
249 * don't want to drop and re-establish P2P connections simply due to
252 GNUNET_CORE_KX_STATE_REKEY_SENT,
255 * Last state of a KX (when it is being terminated). Set
256 * just before CORE frees the internal state for this peer.
258 GNUNET_CORE_KX_PEER_DISCONNECT,
261 * This is not a state in a peer's state machine, but a special
262 * value used with the #GNUNET_CORE_MonitorCallback to indicate
263 * that we finished the initial iteration over the peers.
265 GNUNET_CORE_KX_ITERATION_FINISHED,
268 * This is not a state in a peer's state machine, but a special
269 * value used with the #GNUNET_CORE_MonitorCallback to indicate
270 * that we lost the connection to the CORE service (and will try
271 * to reconnect). If this happens, most likely the CORE service
272 * crashed and thus all connection state should be assumed lost.
274 GNUNET_CORE_KX_CORE_DISCONNECT
280 * Function called by the monitor callback whenever
281 * a peer's connection status changes.
284 * @param pid identity of the peer this update is about
285 * @param state current key exchange state of the peer
286 * @param timeout when does the current state expire
289 (*GNUNET_CORE_MonitorCallback)(void *cls,
290 const struct GNUNET_PeerIdentity *pid,
291 enum GNUNET_CORE_KxState state,
292 struct GNUNET_TIME_Absolute timeout);
296 * Monitor connectivity and KX status of all peers known to CORE.
297 * Calls @a peer_cb with the current status for each connected peer,
298 * and then once with NULL to indicate that all peers that are
299 * currently active have been handled. After that, the iteration
300 * continues until it is cancelled. Normal users of the CORE API are
301 * not expected to use this function. It is different in that it
302 * truly lists all connections (including those where the KX is in
303 * progress), not just those relevant to the application. This
304 * function is used by special applications for diagnostics.
306 * @param cfg configuration handle
307 * @param peer_cb function to call with the peer information
308 * @param peer_cb_cls closure for @a peer_cb
309 * @return NULL on error
311 struct GNUNET_CORE_MonitorHandle *
312 GNUNET_CORE_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
313 GNUNET_CORE_MonitorCallback peer_cb,
318 * Stop monitoring CORE activity.
320 * @param mh monitor to stop
323 GNUNET_CORE_monitor_stop (struct GNUNET_CORE_MonitorHandle *mh);
327 * Check if the given peer is currently connected. This function is for special
328 * cirumstances (GNUNET_TESTBED uses it), normal users of the CORE API are
329 * expected to track which peers are connected based on the connect/disconnect
330 * callbacks from #GNUNET_CORE_connect. This function is NOT part of the
331 * 'versioned', 'official' API. This function returns
332 * synchronously after looking in the CORE API cache.
334 * @param h the core handle
335 * @param pid the identity of the peer to check if it has been connected to us
336 * @return #GNUNET_YES if the peer is connected to us; #GNUNET_NO if not
339 GNUNET_CORE_is_peer_connected_sync (const struct GNUNET_CORE_Handle *h,
340 const struct GNUNET_PeerIdentity *pid);
344 * Create a message queue for sending messages to a peer with CORE.
345 * Messages may only be queued with #GNUNET_MQ_send once the init callback has
346 * been called for the given handle.
347 * There must only be one queue per peer for each core handle.
348 * The message queue can only be used to transmit messages,
349 * not to receive them.
351 * @param h the core handle
352 * @param target the target peer for this queue, may not be NULL
353 * @return a message queue for sending messages over the core handle
356 struct GNUNET_MQ_Handle *
357 GNUNET_CORE_mq_create (struct GNUNET_CORE_Handle *h,
358 const struct GNUNET_PeerIdentity *target);
361 #if 0 /* keep Emacsens' auto-indent happy */
368 /* ifndef GNUNET_CORE_SERVICE_H */
371 /** @} */ /* end of group core */
373 /* end of gnunet_core_service.h */