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3 Copyright (C) 2009-2017 GNUnet e.V.
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
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13 Affero General Public License for more details.
16 * @author Christian Grothoff
18 * @file include/gnunet_core_service.h
19 * Core service; the main API for encrypted P2P communications
21 * @defgroup core Core service
22 * Encrypted direct communication between peers
24 * @see [Documentation](https://gnunet.org/gnunet-core-subsystem)
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,
92 struct GNUNET_MQ_Handle *mq);
96 * Method called whenever a peer disconnects.
99 * @param peer peer identity this notification is about
102 (*GNUNET_CORE_DisconnectEventHandler) (void *cls,
103 const struct GNUNET_PeerIdentity *peer,
108 * Function called after #GNUNET_CORE_connect has succeeded (or failed
109 * for good). Note that the private key of the peer is intentionally
110 * not exposed here; if you need it, your process should try to read
111 * the private key file directly (which should work if you are
112 * authorized...). Implementations of this function must not call
113 * #GNUNET_CORE_disconnect (other than by scheduling a new task to
117 * @param my_identity ID of this peer, NULL if we failed
120 (*GNUNET_CORE_StartupCallback) (void *cls,
121 const struct GNUNET_PeerIdentity *my_identity);
125 * Connect to the core service. Note that the connection may complete
126 * (or fail) asynchronously. This function primarily causes the given
127 * callback notification functions to be invoked whenever the
128 * specified event happens. The maximum number of queued
129 * notifications (queue length) is per client; the queue is shared
130 * across all types of notifications. So a slow client that registers
131 * for @a outbound_notify also risks missing @a inbound_notify messages.
132 * Certain events (such as connect/disconnect notifications) are not
133 * subject to queue size limitations.
135 * @param cfg configuration to use
136 * @param cls closure for the various callbacks that follow (including handlers in the handlers array)
137 * @param init callback to call once we have successfully
138 * connected to the core service
139 * @param connects function to call on peer connect, can be NULL
140 * @param disconnects function to call on peer disconnect / timeout, can be NULL
141 * @param handlers callbacks for messages we care about, NULL-terminated
142 * note that the core is allowed to drop notifications about inbound
143 * messages if the client does not process them fast enough (for this
144 * notification type, a bounded queue is used)
145 * @return handle to the core service (only useful for disconnect until @a init is called),
146 * NULL on error (in this case, init is never called)
148 struct GNUNET_CORE_Handle *
149 GNUNET_CORE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
151 GNUNET_CORE_StartupCallback init,
152 GNUNET_CORE_ConnectEventHandler connects,
153 GNUNET_CORE_DisconnectEventHandler disconnects,
154 const struct GNUNET_MQ_MessageHandler *handlers);
158 * Disconnect from the core service.
160 * @param handle connection to core to disconnect
163 GNUNET_CORE_disconnect (struct GNUNET_CORE_Handle *handle);
167 * Inquire with CORE what options should be set for a message
168 * so that it is transmitted with the given @a priority and
169 * the given @a cork value.
171 * @param cork desired corking
172 * @param priority desired message priority
173 * @param[out] flags set to `flags` value for #GNUNET_MQ_set_options()
174 * @return `extra` argument to give to #GNUNET_MQ_set_options()
177 GNUNET_CORE_get_mq_options (int cork,
178 enum GNUNET_CORE_Priority priority,
183 * Obtain the message queue for a connected peer.
185 * @param h the core handle
186 * @param pid the identity of the peer
187 * @return NULL if @a pid is not connected
189 struct GNUNET_MQ_Handle *
190 GNUNET_CORE_get_mq (const struct GNUNET_CORE_Handle *h,
191 const struct GNUNET_PeerIdentity *pid);
195 * Handle to a CORE monitoring operation.
197 struct GNUNET_CORE_MonitorHandle;
201 * State machine for our P2P encryption handshake. Everyone starts in
202 * #GNUNET_CORE_KX_STATE_DOWN, if we receive the other peer's key
203 * (other peer initiated) we start in state
204 * #GNUNET_CORE_KX_STATE_KEY_RECEIVED (since we will immediately send
205 * our own); otherwise we start in #GNUNET_CORE_KX_STATE_KEY_SENT. If
206 * we get back a PONG from within either state, we move up to
207 * #GNUNET_CORE_KX_STATE_UP (the PONG will always be sent back
208 * encrypted with the key we sent to the other peer). Eventually,
209 * we will try to rekey, for this we will enter
210 * #GNUNET_CORE_KX_STATE_REKEY_SENT until the rekey operation is
211 * confirmed by a PONG from the other peer.
213 enum GNUNET_CORE_KxState
218 GNUNET_CORE_KX_STATE_DOWN = 0,
221 * We've sent our session key.
223 GNUNET_CORE_KX_STATE_KEY_SENT,
226 * We've received the other peers session key.
228 GNUNET_CORE_KX_STATE_KEY_RECEIVED,
231 * The other peer has confirmed our session key + PING with a PONG
232 * message encrypted with his session key (which we got). Key
235 GNUNET_CORE_KX_STATE_UP,
238 * We're rekeying (or had a timeout), so we have sent the other peer
239 * our new ephemeral key, but we did not get a matching PONG yet.
240 * This is equivalent to being #GNUNET_CORE_KX_STATE_KEY_RECEIVED,
241 * except that the session is marked as 'up' with sessions (as we
242 * don't want to drop and re-establish P2P connections simply due to
245 GNUNET_CORE_KX_STATE_REKEY_SENT,
248 * Last state of a KX (when it is being terminated). Set
249 * just before CORE frees the internal state for this peer.
251 GNUNET_CORE_KX_PEER_DISCONNECT,
254 * This is not a state in a peer's state machine, but a special
255 * value used with the #GNUNET_CORE_MonitorCallback to indicate
256 * that we finished the initial iteration over the peers.
258 GNUNET_CORE_KX_ITERATION_FINISHED,
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 lost the connection to the CORE service (and will try
264 * to reconnect). If this happens, most likely the CORE service
265 * crashed and thus all connection state should be assumed lost.
267 GNUNET_CORE_KX_CORE_DISCONNECT
273 * Function called by the monitor callback whenever
274 * a peer's connection status changes.
277 * @param pid identity of the peer this update is about
278 * @param state current key exchange state of the peer
279 * @param timeout when does the current state expire
282 (*GNUNET_CORE_MonitorCallback)(void *cls,
283 const struct GNUNET_PeerIdentity *pid,
284 enum GNUNET_CORE_KxState state,
285 struct GNUNET_TIME_Absolute timeout);
289 * Monitor connectivity and KX status of all peers known to CORE.
290 * Calls @a peer_cb with the current status for each connected peer,
291 * and then once with NULL to indicate that all peers that are
292 * currently active have been handled. After that, the iteration
293 * continues until it is cancelled. Normal users of the CORE API are
294 * not expected to use this function. It is different in that it
295 * truly lists all connections (including those where the KX is in
296 * progress), not just those relevant to the application. This
297 * function is used by special applications for diagnostics.
299 * @param cfg configuration handle
300 * @param peer_cb function to call with the peer information
301 * @param peer_cb_cls closure for @a peer_cb
302 * @return NULL on error
304 struct GNUNET_CORE_MonitorHandle *
305 GNUNET_CORE_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
306 GNUNET_CORE_MonitorCallback peer_cb,
311 * Stop monitoring CORE activity.
313 * @param mh monitor to stop
316 GNUNET_CORE_monitor_stop (struct GNUNET_CORE_MonitorHandle *mh);
320 * Check if the given peer is currently connected. This function is for special
321 * cirumstances (GNUNET_TESTBED uses it), normal users of the CORE API are
322 * expected to track which peers are connected based on the connect/disconnect
323 * callbacks from #GNUNET_CORE_connect. This function is NOT part of the
324 * 'versioned', 'official' API. This function returns
325 * synchronously after looking in the CORE API cache.
327 * @param h the core handle
328 * @param pid the identity of the peer to check if it has been connected to us
329 * @return #GNUNET_YES if the peer is connected to us; #GNUNET_NO if not
332 GNUNET_CORE_is_peer_connected_sync (const struct GNUNET_CORE_Handle *h,
333 const struct GNUNET_PeerIdentity *pid);
337 * Create a message queue for sending messages to a peer with CORE.
338 * Messages may only be queued with #GNUNET_MQ_send once the init callback has
339 * been called for the given handle.
340 * There must only be one queue per peer for each core handle.
341 * The message queue can only be used to transmit messages,
342 * not to receive them.
344 * @param h the core handle
345 * @param target the target peer for this queue, may not be NULL
346 * @return a message queue for sending messages over the core handle
349 struct GNUNET_MQ_Handle *
350 GNUNET_CORE_mq_create (struct GNUNET_CORE_Handle *h,
351 const struct GNUNET_PeerIdentity *target);
354 #if 0 /* keep Emacsens' auto-indent happy */
361 /* ifndef GNUNET_CORE_SERVICE_H */
364 /** @} */ /* end of group core */
366 /* end of gnunet_core_service.h */