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3 Copyright (C) 2009-2017 GNUnet e.V.
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18 SPDX-License-Identifier: AGPL3.0-or-later
21 * @author Christian Grothoff
23 * @file include/gnunet_core_service.h
24 * Core service; the main API for encrypted P2P communications
26 * @defgroup core Core service
27 * Encrypted direct communication between peers
29 * @see [Documentation](https://gnunet.org/gnunet-core-subsystem)
33 #ifndef GNUNET_CORE_SERVICE_H
34 #define GNUNET_CORE_SERVICE_H
39 #if 0 /* keep Emacsens' auto-indent happy */
44 #include "gnunet_util_lib.h"
45 #include "gnunet_transport_service.h"
48 * Version number of GNUnet-core API.
50 #define GNUNET_CORE_VERSION 0x00000001
55 enum GNUNET_CORE_Priority
59 * Lowest priority, i.e. background traffic (i.e. fs)
61 GNUNET_CORE_PRIO_BACKGROUND = 0,
64 * Normal traffic (i.e. cadet/dv relay, DHT)
66 GNUNET_CORE_PRIO_BEST_EFFORT = 1,
69 * Urgent traffic (local peer, i.e. conversation).
71 GNUNET_CORE_PRIO_URGENT = 2,
74 * Highest priority, control traffic (i.e. NSE, Core/Cadet KX).
76 GNUNET_CORE_PRIO_CRITICAL_CONTROL = 3
83 * Opaque handle to the service.
85 struct GNUNET_CORE_Handle;
89 * Method called whenever a given peer connects.
92 * @param peer peer identity this notification is about
93 * @return closure associated with @a peer. given to mq callbacks and
94 * #GNUNET_CORE_DisconnectEventHandler
97 (*GNUNET_CORE_ConnectEventHandler) (void *cls,
98 const struct GNUNET_PeerIdentity *peer,
99 struct GNUNET_MQ_Handle *mq);
103 * Method called whenever a peer disconnects.
106 * @param peer peer identity this notification is about
107 * @param peer_cls closure associated with peer. given in
108 * #GNUNET_CORE_ConnectEventHandler
111 (*GNUNET_CORE_DisconnectEventHandler) (void *cls,
112 const struct GNUNET_PeerIdentity *peer,
117 * Function called after #GNUNET_CORE_connect has succeeded (or failed
118 * for good). Note that the private key of the peer is intentionally
119 * not exposed here; if you need it, your process should try to read
120 * the private key file directly (which should work if you are
121 * authorized...). Implementations of this function must not call
122 * #GNUNET_CORE_disconnect (other than by scheduling a new task to
126 * @param my_identity ID of this peer, NULL if we failed
129 (*GNUNET_CORE_StartupCallback) (void *cls,
130 const struct GNUNET_PeerIdentity *my_identity);
134 * Connect to the core service. Note that the connection may complete
135 * (or fail) asynchronously. This function primarily causes the given
136 * callback notification functions to be invoked whenever the
137 * specified event happens. The maximum number of queued
138 * notifications (queue length) is per client; the queue is shared
139 * across all types of notifications. So a slow client that registers
140 * for @a outbound_notify also risks missing @a inbound_notify messages.
141 * Certain events (such as connect/disconnect notifications) are not
142 * subject to queue size limitations.
144 * @param cfg configuration to use
145 * @param cls closure for the various callbacks that follow (including handlers in the handlers array)
146 * @param init callback to call once we have successfully
147 * connected to the core service
148 * @param connects function to call on peer connect, can be NULL
149 * @param disconnects function to call on peer disconnect / timeout, can be NULL
150 * @param handlers callbacks for messages we care about, NULL-terminated
151 * note that the core is allowed to drop notifications about inbound
152 * messages if the client does not process them fast enough (for this
153 * notification type, a bounded queue is used)
154 * @return handle to the core service (only useful for disconnect until @a init is called),
155 * NULL on error (in this case, init is never called)
157 struct GNUNET_CORE_Handle *
158 GNUNET_CORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
160 GNUNET_CORE_StartupCallback init,
161 GNUNET_CORE_ConnectEventHandler connects,
162 GNUNET_CORE_DisconnectEventHandler disconnects,
163 const struct GNUNET_MQ_MessageHandler *handlers);
167 * Disconnect from the core service.
169 * @param handle connection to core to disconnect
172 GNUNET_CORE_disconnect (struct GNUNET_CORE_Handle *handle);
176 * Inquire with CORE what options should be set for a message
177 * so that it is transmitted with the given @a priority and
178 * the given @a cork value.
180 * @param cork desired corking
181 * @param priority desired message priority
182 * @param[out] flags set to `flags` value for #GNUNET_MQ_set_options()
183 * @return `extra` argument to give to #GNUNET_MQ_set_options()
186 GNUNET_CORE_get_mq_options (int cork,
187 enum GNUNET_CORE_Priority priority,
192 * Obtain the message queue for a connected peer.
194 * @param h the core handle
195 * @param pid the identity of the peer
196 * @return NULL if @a pid is not connected
198 struct GNUNET_MQ_Handle *
199 GNUNET_CORE_get_mq (const struct GNUNET_CORE_Handle *h,
200 const struct GNUNET_PeerIdentity *pid);
204 * Handle to a CORE monitoring operation.
206 struct GNUNET_CORE_MonitorHandle;
210 * State machine for our P2P encryption handshake. Everyone starts in
211 * #GNUNET_CORE_KX_STATE_DOWN, if we receive the other peer's key
212 * (other peer initiated) we start in state
213 * #GNUNET_CORE_KX_STATE_KEY_RECEIVED (since we will immediately send
214 * our own); otherwise we start in #GNUNET_CORE_KX_STATE_KEY_SENT. If
215 * we get back a PONG from within either state, we move up to
216 * #GNUNET_CORE_KX_STATE_UP (the PONG will always be sent back
217 * encrypted with the key we sent to the other peer). Eventually,
218 * we will try to rekey, for this we will enter
219 * #GNUNET_CORE_KX_STATE_REKEY_SENT until the rekey operation is
220 * confirmed by a PONG from the other peer.
222 enum GNUNET_CORE_KxState
227 GNUNET_CORE_KX_STATE_DOWN = 0,
230 * We've sent our session key.
232 GNUNET_CORE_KX_STATE_KEY_SENT,
235 * We've received the other peers session key.
237 GNUNET_CORE_KX_STATE_KEY_RECEIVED,
240 * The other peer has confirmed our session key + PING with a PONG
241 * message encrypted with their session key (which we got). Key
244 GNUNET_CORE_KX_STATE_UP,
247 * We're rekeying (or had a timeout), so we have sent the other peer
248 * our new ephemeral key, but we did not get a matching PONG yet.
249 * This is equivalent to being #GNUNET_CORE_KX_STATE_KEY_RECEIVED,
250 * except that the session is marked as 'up' with sessions (as we
251 * don't want to drop and re-establish P2P connections simply due to
254 GNUNET_CORE_KX_STATE_REKEY_SENT,
257 * Last state of a KX (when it is being terminated). Set
258 * just before CORE frees the internal state for this peer.
260 GNUNET_CORE_KX_PEER_DISCONNECT,
263 * This is not a state in a peer's state machine, but a special
264 * value used with the #GNUNET_CORE_MonitorCallback to indicate
265 * that we finished the initial iteration over the peers.
267 GNUNET_CORE_KX_ITERATION_FINISHED,
270 * This is not a state in a peer's state machine, but a special
271 * value used with the #GNUNET_CORE_MonitorCallback to indicate
272 * that we lost the connection to the CORE service (and will try
273 * to reconnect). If this happens, most likely the CORE service
274 * crashed and thus all connection state should be assumed lost.
276 GNUNET_CORE_KX_CORE_DISCONNECT
282 * Function called by the monitor callback whenever
283 * a peer's connection status changes.
286 * @param pid identity of the peer this update is about
287 * @param state current key exchange state of the peer
288 * @param timeout when does the current state expire
291 (*GNUNET_CORE_MonitorCallback)(void *cls,
292 const struct GNUNET_PeerIdentity *pid,
293 enum GNUNET_CORE_KxState state,
294 struct GNUNET_TIME_Absolute timeout);
298 * Monitor connectivity and KX status of all peers known to CORE.
299 * Calls @a peer_cb with the current status for each connected peer,
300 * and then once with NULL to indicate that all peers that are
301 * currently active have been handled. After that, the iteration
302 * continues until it is cancelled. Normal users of the CORE API are
303 * not expected to use this function. It is different in that it
304 * truly lists all connections (including those where the KX is in
305 * progress), not just those relevant to the application. This
306 * function is used by special applications for diagnostics.
308 * @param cfg configuration handle
309 * @param peer_cb function to call with the peer information
310 * @param peer_cb_cls closure for @a peer_cb
311 * @return NULL on error
313 struct GNUNET_CORE_MonitorHandle *
314 GNUNET_CORE_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
315 GNUNET_CORE_MonitorCallback peer_cb,
320 * Stop monitoring CORE activity.
322 * @param mh monitor to stop
325 GNUNET_CORE_monitor_stop (struct GNUNET_CORE_MonitorHandle *mh);
329 * Check if the given peer is currently connected. This function is for special
330 * cirumstances (GNUNET_TESTBED uses it), normal users of the CORE API are
331 * expected to track which peers are connected based on the connect/disconnect
332 * callbacks from #GNUNET_CORE_connect. This function is NOT part of the
333 * 'versioned', 'official' API. This function returns
334 * synchronously after looking in the CORE API cache.
336 * @param h the core handle
337 * @param pid the identity of the peer to check if it has been connected to us
338 * @return #GNUNET_YES if the peer is connected to us; #GNUNET_NO if not
341 GNUNET_CORE_is_peer_connected_sync (const struct GNUNET_CORE_Handle *h,
342 const struct GNUNET_PeerIdentity *pid);
346 * Create a message queue for sending messages to a peer with CORE.
347 * Messages may only be queued with #GNUNET_MQ_send once the init callback has
348 * been called for the given handle.
349 * There must only be one queue per peer for each core handle.
350 * The message queue can only be used to transmit messages,
351 * not to receive them.
353 * @param h the core handle
354 * @param target the target peer for this queue, may not be NULL
355 * @return a message queue for sending messages over the core handle
358 struct GNUNET_MQ_Handle *
359 GNUNET_CORE_mq_create (struct GNUNET_CORE_Handle *h,
360 const struct GNUNET_PeerIdentity *target);
363 #if 0 /* keep Emacsens' auto-indent happy */
370 /* ifndef GNUNET_CORE_SERVICE_H */
373 /** @} */ /* end of group core */
375 /* end of gnunet_core_service.h */