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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 Affero General Public License as published
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18 SPDX-License-Identifier: AGPL3.0-or-later
21 * @author Christian Grothoff
25 * CADET service; establish channels to distant peers
27 * @defgroup cadet CADET service
28 * Confidential Ad-hoc Decentralized End-to-End Transport
30 * @see [Documentation](https://gnunet.org/cadet-subsystem)
31 * @see [Paper](https://gnunet.org/cadet)
35 #ifndef GNUNET_CADET_SERVICE_H
36 #define GNUNET_CADET_SERVICE_H
40 #if 0 /* keep Emacsens' auto-indent happy */
45 #include "gnunet_util_lib.h"
46 #include "gnunet_transport_service.h"
49 * Version number of GNUnet-cadet API.
51 #define GNUNET_CADET_VERSION 0x00000005
55 * Opaque handle to the service.
57 struct GNUNET_CADET_Handle;
60 * Opaque handle to a channel.
62 struct GNUNET_CADET_Channel;
65 * Opaque handle to a port.
67 struct GNUNET_CADET_Port;
71 * Hash uniquely identifying a connection below a tunnel.
73 struct GNUNET_CADET_ConnectionTunnelIdentifier
75 struct GNUNET_ShortHashCode connection_of_tunnel;
80 * Number identifying a CADET channel within a tunnel.
82 struct GNUNET_CADET_ChannelTunnelNumber
85 * Which number does this channel have that uniquely identfies
86 * it within its tunnel, in network byte order.
88 * Given two peers, both may initiate channels over the same tunnel.
89 * The @e cn must be greater or equal to 0x80000000 (high-bit set)
90 * for tunnels initiated with the peer that has the larger peer
91 * identity as compared using #GNUNET_memcmp().
93 uint32_t cn GNUNET_PACKED;
97 * Method called whenever a peer connects to a port in MQ-based CADET.
99 * @param cls Closure from #GNUNET_CADET_open_port.
100 * @param channel New handle to the channel.
101 * @param source Peer that started this channel.
102 * @return Closure for the incoming @a channel. It's given to:
103 * - The #GNUNET_CADET_DisconnectEventHandler (given to
104 * #GNUNET_CADET_open_port) when the channel dies.
105 * - Each the #GNUNET_MQ_MessageCallback handlers for each message
106 * received on the @a channel.
108 typedef void *(*GNUNET_CADET_ConnectEventHandler) (
110 struct GNUNET_CADET_Channel *channel,
111 const struct GNUNET_PeerIdentity *source);
115 * Function called whenever an MQ-channel is destroyed, unless the destruction
116 * was requested by #GNUNET_CADET_channel_destroy.
117 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
119 * It should clean up any associated state, including cancelling any pending
120 * transmission on this channel.
122 * @param cls Channel closure.
123 * @param channel Connection to the other end (henceforth invalid).
125 typedef void (*GNUNET_CADET_DisconnectEventHandler) (
127 const struct GNUNET_CADET_Channel *channel);
131 * Function called whenever an MQ-channel's transmission window size changes.
133 * The first callback in an outgoing channel will be with a non-zero value
134 * and will mean the channel is connected to the destination.
136 * For an incoming channel it will be called immediately after the
137 * #GNUNET_CADET_ConnectEventHandler, also with a non-zero value.
139 * @param cls Channel closure.
140 * @param channel Connection to the other end --- FIXME: drop?
141 * @param window_size New window size. If the is more messages than buffer size
142 * this value will be negative. -- FIXME: make unsigned, we never call negative?
144 typedef void (*GNUNET_CADET_WindowSizeEventHandler) (
146 const struct GNUNET_CADET_Channel *channel,
151 * Connect to the MQ-based cadet service.
153 * @param cfg Configuration to use.
154 * @return Handle to the cadet service NULL on error.
156 struct GNUNET_CADET_Handle *
157 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg);
161 * Disconnect from the cadet service. All channels will be destroyed. All channel
162 * disconnect callbacks will be called on any still connected peers, notifying
163 * about their disconnection. The registered inbound channel cleaner will be
164 * called should any inbound channels still exist.
166 * @param handle connection to cadet to disconnect
169 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
173 * Open a port to receive incomming MQ-based channels.
175 * @param h CADET handle.
176 * @param port Hash identifying the port.
177 * @param connects Function called when an incoming channel is connected.
178 * @param connects_cls Closure for the @a connects handler.
179 * @param window_changes Function called when the transmit window size changes.
181 * @param disconnects Function called when a channel is disconnected.
182 * @param handlers Callbacks for messages we care about, NULL-terminated.
183 * @return Port handle, NULL if port is in use
185 struct GNUNET_CADET_Port *
186 GNUNET_CADET_open_port (struct GNUNET_CADET_Handle *h,
187 const struct GNUNET_HashCode *port,
188 GNUNET_CADET_ConnectEventHandler connects,
190 GNUNET_CADET_WindowSizeEventHandler window_changes,
191 GNUNET_CADET_DisconnectEventHandler disconnects,
192 const struct GNUNET_MQ_MessageHandler *handlers);
196 * Close a port opened with @a GNUNET_CADET_open_port.
197 * The @a new_channel callback will no longer be called.
199 * @param p Port handle.
202 GNUNET_CADET_close_port (struct GNUNET_CADET_Port *p);
206 * Create a new channel towards a remote peer.
208 * If the destination peer closes the channel after accepting it,
209 * @a disconnects will be called for this channel (unless
210 * #GNUNET_CADET_channel_destroy() was called on this end first).
212 * @param h CADET handle.
213 * @param channel_cls Closure for the channel. It's given to:
214 * - The management handler @a window_changes.
215 * - The disconnect handler @a disconnects
216 * - Each message type callback in @a handlers
217 * @param destination Peer identity the channel should go to.
218 * @param port Identification of the destination port.
219 * @param window_changes Function called when the transmit window size changes.
220 * Can be NULL if this data is of no interest.
221 * @param disconnects Function called when the channel is disconnected.
222 * @param handlers Callbacks for messages we care about, NULL-terminated.
223 * @return Handle to the channel.
225 struct GNUNET_CADET_Channel *
226 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
228 const struct GNUNET_PeerIdentity *destination,
229 const struct GNUNET_HashCode *port,
230 GNUNET_CADET_WindowSizeEventHandler window_changes,
231 GNUNET_CADET_DisconnectEventHandler disconnects,
232 const struct GNUNET_MQ_MessageHandler *handlers);
236 * Destroy an existing channel.
238 * The existing end callback for the channel will NOT be called.
239 * Any pending outgoing messages will be sent but no incoming messages will be
240 * accepted and no data callbacks will be called.
242 * @param channel Channel handle, becomes invalid after this call.
245 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
249 * Obtain the message queue for a connected channel.
251 * @param channel The channel handle from which to get the MQ.
252 * @return The message queue of the channel.
254 struct GNUNET_MQ_Handle *
255 GNUNET_CADET_get_mq (const struct GNUNET_CADET_Channel *channel);
259 * Indicate readiness to receive the next message on a channel.
261 * Should only be called once per handler called.
263 * @param channel Channel that will be allowed to call another handler.
266 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
270 * Transitional function to convert an unsigned int port to a hash value.
271 * WARNING: local static value returned, NOT reentrant!
272 * WARNING: do not use this function for new code!
274 * @param port Numerical port (unsigned int format).
276 * @return A GNUNET_HashCode usable for the new CADET API.
278 const struct GNUNET_HashCode *
279 GC_u2h (uint32_t port);
281 enum GNUNET_CADET_ChannelInfoOption
284 * Who is the peer at the other end of the channel.
285 * Only for use in @c GNUNET_CADET_channel_get_info
286 * struct GNUNET_PeerIdentity *peer
288 GNUNET_CADET_OPTION_PEER = 0x0
292 * Union to retrieve info about a channel.
294 union GNUNET_CADET_ChannelInfo
297 * #GNUNET_YES / #GNUNET_NO, for binary flags.
302 * Peer on the other side of the channel
304 const struct GNUNET_PeerIdentity peer;
309 * Get information about a channel.
311 * @param channel Channel handle.
312 * @param ... dependant on option, currently not used
313 * @return Union with an answer to the query.
315 const union GNUNET_CADET_ChannelInfo *
316 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
317 enum GNUNET_CADET_ChannelInfoOption option,
321 /******************************************************************************/
322 /******************** MONITORING /DEBUG API *************************/
323 /******************************************************************************/
324 /* The following calls are not useful for normal CADET operation, but for */
325 /* debug and monitoring of the cadet state. They can be safely ignored. */
326 /* The API can change at any point without notice. */
327 /* Please contact the developer if you consider any of this calls useful for */
328 /* normal cadet applications. */
329 /******************************************************************************/
333 * Internal details about a channel.
335 struct GNUNET_CADET_ChannelInternals
338 * Root of the channel
340 struct GNUNET_PeerIdentity root;
343 * Destination of the channel
345 struct GNUNET_PeerIdentity dest;
352 * Method called to retrieve information about a specific channel the cadet peer
353 * is aware of, including all transit nodes.
355 * @param cls Closure.
356 * @param info internal details, NULL for end of list
358 typedef void (*GNUNET_CADET_ChannelCB) (
360 const struct GNUNET_CADET_ChannelInternals *info);
366 struct GNUNET_CADET_ChannelMonitor;
370 * Request information about channels to @a peer from the local peer.
372 * @param cfg configuration to use
373 * @param peer ID of the other end of the channel.
374 * @param callback Function to call with the requested data.
375 * @param callback_cls Closure for @c callback.
377 struct GNUNET_CADET_ChannelMonitor *
378 GNUNET_CADET_get_channel (const struct GNUNET_CONFIGURATION_Handle *cfg,
379 struct GNUNET_PeerIdentity *peer,
380 GNUNET_CADET_ChannelCB callback,
385 * Cancel a channel monitor request. The callback will not be called (anymore).
387 * @param h Cadet handle.
388 * @return Closure that was given to #GNUNET_CADET_get_channel().
391 GNUNET_CADET_get_channel_cancel (struct GNUNET_CADET_ChannelMonitor *cm);
395 * Information we return per peer.
397 struct GNUNET_CADET_PeerListEntry
400 * Which peer is the information about?
402 struct GNUNET_PeerIdentity peer;
405 * Do we have a tunnel to this peer?
410 * Number of disjoint known paths to @e peer.
412 unsigned int n_paths;
415 * Length of the shortest path (0 = unknown, 1 = ourselves, 2 = direct neighbour).
417 unsigned int best_path_length;
422 * Method called to retrieve information about all peers in CADET, called
425 * After last peer has been reported, an additional call with NULL is done.
427 * @param cls Closure.
428 * @param ple information about a peer, or NULL on "EOF".
430 typedef void (*GNUNET_CADET_PeersCB) (
432 const struct GNUNET_CADET_PeerListEntry *ple);
438 struct GNUNET_CADET_PeersLister;
442 * Request information about peers known to the running cadet service.
443 * The callback will be called for every peer known to the service.
444 * Only one info request (of any kind) can be active at once.
446 * @param cfg configuration to use
447 * @param callback Function to call with the requested data.
448 * @param callback_cls Closure for @c callback.
449 * @return NULL on error
451 struct GNUNET_CADET_PeersLister *
452 GNUNET_CADET_list_peers (const struct GNUNET_CONFIGURATION_Handle *cfg,
453 GNUNET_CADET_PeersCB callback,
458 * Cancel a peer info request. The callback will not be called (anymore).
460 * @param pl operation handle
461 * @return Closure that was given to #GNUNET_CADET_list_peers().
464 GNUNET_CADET_list_peers_cancel (struct GNUNET_CADET_PeersLister *pl);
468 * Detailed information we return per peer.
470 struct GNUNET_CADET_PeerPathDetail
473 * Peer this is about.
475 struct GNUNET_PeerIdentity peer;
478 * Offset of the target peer on the @e path.
480 unsigned int target_offset;
483 * Number of entries on the @e path.
485 unsigned int path_length;
488 * Array of PEER_IDs representing all paths to reach the peer. Each
489 * path starts with the first hop (local peer not included). Each
490 * path ends with the destination peer (given in @e peer).
492 const struct GNUNET_PeerIdentity *path;
497 * Method called to retrieve information about a specific path
498 * known to the service.
500 * @param cls Closure.
501 * @param ppd details about a path to the peer, NULL for end of information
503 typedef void (*GNUNET_CADET_PathCB) (
505 const struct GNUNET_CADET_PeerPathDetail *ppd);
509 * Handle to cancel #GNUNET_CADET_get_path() operation.
511 struct GNUNET_CADET_GetPath;
515 * Request information about a peer known to the running cadet peer.
517 * @param cfg configuration to use
518 * @param id Peer whose paths we want to examine.
519 * @param callback Function to call with the requested data.
520 * @param callback_cls Closure for @c callback.
521 * @return NULL on error
523 struct GNUNET_CADET_GetPath *
524 GNUNET_CADET_get_path (const struct GNUNET_CONFIGURATION_Handle *cfg,
525 const struct GNUNET_PeerIdentity *id,
526 GNUNET_CADET_PathCB callback,
531 * Cancel @a gp operation.
533 * @param gp operation to cancel
534 * @return closure from #GNUNET_CADET_get_path().
537 GNUNET_CADET_get_path_cancel (struct GNUNET_CADET_GetPath *gp);
541 * Details about a tunnel managed by CADET.
543 struct GNUNET_CADET_TunnelDetails
546 * Target of the tunnel.
548 struct GNUNET_PeerIdentity peer;
551 * How many channels use the tunnel.
556 * How many connections support the tunnel.
558 uint32_t connections;
561 * What is our encryption state?
566 * What is our connectivity state?
573 * Method called to retrieve information about all tunnels in CADET, called
576 * After last tunnel has been reported, an additional call with NULL is done.
578 * @param cls Closure.
579 * @param td tunnel details, NULL for end of list
581 typedef void (*GNUNET_CADET_TunnelsCB) (
583 const struct GNUNET_CADET_TunnelDetails *td);
589 struct GNUNET_CADET_ListTunnels;
593 * Request information about tunnels of the running cadet peer.
594 * The callback will be called for every tunnel of the service.
595 * Only one info request (of any kind) can be active at once.
597 * @param cfg configuration to use
598 * @param callback Function to call with the requested data.
599 * @param callback_cls Closure for @c callback.
600 * @return NULL on error
602 struct GNUNET_CADET_ListTunnels *
603 GNUNET_CADET_list_tunnels (const struct GNUNET_CONFIGURATION_Handle *cfg,
604 GNUNET_CADET_TunnelsCB callback,
609 * Cancel a monitor request. The monitor callback will not be called.
611 * @param lt operation handle
612 * @return Closure given to #GNUNET_CADET_list_tunnels(), if any.
615 GNUNET_CADET_list_tunnels_cancel (struct GNUNET_CADET_ListTunnels *lt);
618 #if 0 /* keep Emacsens' auto-indent happy */
625 /* ifndef GNUNET_CADET_SERVICE_H */
628 /** @} */ /* end of group */
630 /* end of gnunet_cadet_service.h */