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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
93 (*GNUNET_CORE_ConnectEventHandler) (void *cls,
94 const struct GNUNET_PeerIdentity *peer,
95 struct GNUNET_MQ_Handle *mq);
99 * Method called whenever a peer disconnects.
102 * @param peer peer identity this notification is about
105 (*GNUNET_CORE_DisconnectEventHandler) (void *cls,
106 const struct GNUNET_PeerIdentity *peer,
111 * Function called after #GNUNET_CORE_connect has succeeded (or failed
112 * for good). Note that the private key of the peer is intentionally
113 * not exposed here; if you need it, your process should try to read
114 * the private key file directly (which should work if you are
115 * authorized...). Implementations of this function must not call
116 * #GNUNET_CORE_disconnect (other than by scheduling a new task to
120 * @param my_identity ID of this peer, NULL if we failed
123 (*GNUNET_CORE_StartupCallback) (void *cls,
124 const struct GNUNET_PeerIdentity *my_identity);
128 * Connect to the core service. Note that the connection may complete
129 * (or fail) asynchronously. This function primarily causes the given
130 * callback notification functions to be invoked whenever the
131 * specified event happens. The maximum number of queued
132 * notifications (queue length) is per client; the queue is shared
133 * across all types of notifications. So a slow client that registers
134 * for @a outbound_notify also risks missing @a inbound_notify messages.
135 * Certain events (such as connect/disconnect notifications) are not
136 * subject to queue size limitations.
138 * @param cfg configuration to use
139 * @param cls closure for the various callbacks that follow (including handlers in the handlers array)
140 * @param init callback to call once we have successfully
141 * connected to the core service
142 * @param connects function to call on peer connect, can be NULL
143 * @param disconnects function to call on peer disconnect / timeout, can be NULL
144 * @param handlers callbacks for messages we care about, NULL-terminated
145 * note that the core is allowed to drop notifications about inbound
146 * messages if the client does not process them fast enough (for this
147 * notification type, a bounded queue is used)
148 * @return handle to the core service (only useful for disconnect until @a init is called),
149 * NULL on error (in this case, init is never called)
151 struct GNUNET_CORE_Handle *
152 GNUNET_CORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
154 GNUNET_CORE_StartupCallback init,
155 GNUNET_CORE_ConnectEventHandler connects,
156 GNUNET_CORE_DisconnectEventHandler disconnects,
157 const struct GNUNET_MQ_MessageHandler *handlers);
161 * Disconnect from the core service.
163 * @param handle connection to core to disconnect
166 GNUNET_CORE_disconnect (struct GNUNET_CORE_Handle *handle);
170 * Inquire with CORE what options should be set for a message
171 * so that it is transmitted with the given @a priority and
172 * the given @a cork value.
174 * @param cork desired corking
175 * @param priority desired message priority
176 * @param[out] flags set to `flags` value for #GNUNET_MQ_set_options()
177 * @return `extra` argument to give to #GNUNET_MQ_set_options()
180 GNUNET_CORE_get_mq_options (int cork,
181 enum GNUNET_CORE_Priority priority,
186 * Obtain the message queue for a connected peer.
188 * @param h the core handle
189 * @param pid the identity of the peer
190 * @return NULL if @a pid is not connected
192 struct GNUNET_MQ_Handle *
193 GNUNET_CORE_get_mq (const struct GNUNET_CORE_Handle *h,
194 const struct GNUNET_PeerIdentity *pid);
198 * Handle to a CORE monitoring operation.
200 struct GNUNET_CORE_MonitorHandle;
204 * State machine for our P2P encryption handshake. Everyone starts in
205 * #GNUNET_CORE_KX_STATE_DOWN, if we receive the other peer's key
206 * (other peer initiated) we start in state
207 * #GNUNET_CORE_KX_STATE_KEY_RECEIVED (since we will immediately send
208 * our own); otherwise we start in #GNUNET_CORE_KX_STATE_KEY_SENT. If
209 * we get back a PONG from within either state, we move up to
210 * #GNUNET_CORE_KX_STATE_UP (the PONG will always be sent back
211 * encrypted with the key we sent to the other peer). Eventually,
212 * we will try to rekey, for this we will enter
213 * #GNUNET_CORE_KX_STATE_REKEY_SENT until the rekey operation is
214 * confirmed by a PONG from the other peer.
216 enum GNUNET_CORE_KxState
221 GNUNET_CORE_KX_STATE_DOWN = 0,
224 * We've sent our session key.
226 GNUNET_CORE_KX_STATE_KEY_SENT,
229 * We've received the other peers session key.
231 GNUNET_CORE_KX_STATE_KEY_RECEIVED,
234 * The other peer has confirmed our session key + PING with a PONG
235 * message encrypted with his session key (which we got). Key
238 GNUNET_CORE_KX_STATE_UP,
241 * We're rekeying (or had a timeout), so we have sent the other peer
242 * our new ephemeral key, but we did not get a matching PONG yet.
243 * This is equivalent to being #GNUNET_CORE_KX_STATE_KEY_RECEIVED,
244 * except that the session is marked as 'up' with sessions (as we
245 * don't want to drop and re-establish P2P connections simply due to
248 GNUNET_CORE_KX_STATE_REKEY_SENT,
251 * Last state of a KX (when it is being terminated). Set
252 * just before CORE frees the internal state for this peer.
254 GNUNET_CORE_KX_PEER_DISCONNECT,
257 * This is not a state in a peer's state machine, but a special
258 * value used with the #GNUNET_CORE_MonitorCallback to indicate
259 * that we finished the initial iteration over the peers.
261 GNUNET_CORE_KX_ITERATION_FINISHED,
264 * This is not a state in a peer's state machine, but a special
265 * value used with the #GNUNET_CORE_MonitorCallback to indicate
266 * that we lost the connection to the CORE service (and will try
267 * to reconnect). If this happens, most likely the CORE service
268 * crashed and thus all connection state should be assumed lost.
270 GNUNET_CORE_KX_CORE_DISCONNECT
276 * Function called by the monitor callback whenever
277 * a peer's connection status changes.
280 * @param pid identity of the peer this update is about
281 * @param state current key exchange state of the peer
282 * @param timeout when does the current state expire
285 (*GNUNET_CORE_MonitorCallback)(void *cls,
286 const struct GNUNET_PeerIdentity *pid,
287 enum GNUNET_CORE_KxState state,
288 struct GNUNET_TIME_Absolute timeout);
292 * Monitor connectivity and KX status of all peers known to CORE.
293 * Calls @a peer_cb with the current status for each connected peer,
294 * and then once with NULL to indicate that all peers that are
295 * currently active have been handled. After that, the iteration
296 * continues until it is cancelled. Normal users of the CORE API are
297 * not expected to use this function. It is different in that it
298 * truly lists all connections (including those where the KX is in
299 * progress), not just those relevant to the application. This
300 * function is used by special applications for diagnostics.
302 * @param cfg configuration handle
303 * @param peer_cb function to call with the peer information
304 * @param peer_cb_cls closure for @a peer_cb
305 * @return NULL on error
307 struct GNUNET_CORE_MonitorHandle *
308 GNUNET_CORE_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
309 GNUNET_CORE_MonitorCallback peer_cb,
314 * Stop monitoring CORE activity.
316 * @param mh monitor to stop
319 GNUNET_CORE_monitor_stop (struct GNUNET_CORE_MonitorHandle *mh);
323 * Check if the given peer is currently connected. This function is for special
324 * cirumstances (GNUNET_TESTBED uses it), normal users of the CORE API are
325 * expected to track which peers are connected based on the connect/disconnect
326 * callbacks from #GNUNET_CORE_connect. This function is NOT part of the
327 * 'versioned', 'official' API. This function returns
328 * synchronously after looking in the CORE API cache.
330 * @param h the core handle
331 * @param pid the identity of the peer to check if it has been connected to us
332 * @return #GNUNET_YES if the peer is connected to us; #GNUNET_NO if not
335 GNUNET_CORE_is_peer_connected_sync (const struct GNUNET_CORE_Handle *h,
336 const struct GNUNET_PeerIdentity *pid);
340 * Create a message queue for sending messages to a peer with CORE.
341 * Messages may only be queued with #GNUNET_MQ_send once the init callback has
342 * been called for the given handle.
343 * There must only be one queue per peer for each core handle.
344 * The message queue can only be used to transmit messages,
345 * not to receive them.
347 * @param h the core handle
348 * @param target the target peer for this queue, may not be NULL
349 * @return a message queue for sending messages over the core handle
352 struct GNUNET_MQ_Handle *
353 GNUNET_CORE_mq_create (struct GNUNET_CORE_Handle *h,
354 const struct GNUNET_PeerIdentity *target);
357 #if 0 /* keep Emacsens' auto-indent happy */
364 /* ifndef GNUNET_CORE_SERVICE_H */
367 /** @} */ /* end of group core */
369 /* end of gnunet_core_service.h */