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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
293 * Union to retrieve info about a channel.
295 union GNUNET_CADET_ChannelInfo
299 * #GNUNET_YES / #GNUNET_NO, for binary flags.
304 * Peer on the other side of the channel
306 const struct GNUNET_PeerIdentity peer;
311 * Get information about a channel.
313 * @param channel Channel handle.
314 * @param ... dependant on option, currently not used
315 * @return Union with an answer to the query.
317 const union GNUNET_CADET_ChannelInfo *
318 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
319 enum GNUNET_CADET_ChannelInfoOption option,
323 /******************************************************************************/
324 /******************** MONITORING /DEBUG API *************************/
325 /******************************************************************************/
326 /* The following calls are not useful for normal CADET operation, but for */
327 /* debug and monitoring of the cadet state. They can be safely ignored. */
328 /* The API can change at any point without notice. */
329 /* Please contact the developer if you consider any of this calls useful for */
330 /* normal cadet applications. */
331 /******************************************************************************/
335 * Internal details about a channel.
337 struct GNUNET_CADET_ChannelInternals
340 * Root of the channel
342 struct GNUNET_PeerIdentity root;
345 * Destination of the channel
347 struct GNUNET_PeerIdentity dest;
354 * Method called to retrieve information about a specific channel the cadet peer
355 * is aware of, including all transit nodes.
357 * @param cls Closure.
358 * @param info internal details, NULL for end of list
360 typedef void (*GNUNET_CADET_ChannelCB) (
362 const struct GNUNET_CADET_ChannelInternals *info);
368 struct GNUNET_CADET_ChannelMonitor;
372 * Request information about channels to @a peer from the local peer.
374 * @param cfg configuration to use
375 * @param peer ID of the other end of the channel.
376 * @param callback Function to call with the requested data.
377 * @param callback_cls Closure for @c callback.
379 struct GNUNET_CADET_ChannelMonitor *
380 GNUNET_CADET_get_channel (const struct GNUNET_CONFIGURATION_Handle *cfg,
381 struct GNUNET_PeerIdentity *peer,
382 GNUNET_CADET_ChannelCB callback,
387 * Cancel a channel monitor request. The callback will not be called (anymore).
389 * @param h Cadet handle.
390 * @return Closure that was given to #GNUNET_CADET_get_channel().
393 GNUNET_CADET_get_channel_cancel (struct GNUNET_CADET_ChannelMonitor *cm);
397 * Information we return per peer.
399 struct GNUNET_CADET_PeerListEntry
402 * Which peer is the information about?
404 struct GNUNET_PeerIdentity peer;
407 * Do we have a tunnel to this peer?
412 * Number of disjoint known paths to @e peer.
414 unsigned int n_paths;
417 * Length of the shortest path (0 = unknown, 1 = ourselves, 2 = direct neighbour).
419 unsigned int best_path_length;
424 * Method called to retrieve information about all peers in CADET, called
427 * After last peer has been reported, an additional call with NULL is done.
429 * @param cls Closure.
430 * @param ple information about a peer, or NULL on "EOF".
432 typedef void (*GNUNET_CADET_PeersCB) (
434 const struct GNUNET_CADET_PeerListEntry *ple);
440 struct GNUNET_CADET_PeersLister;
444 * Request information about peers known to the running cadet service.
445 * The callback will be called for every peer known to the service.
446 * Only one info request (of any kind) can be active at once.
448 * @param cfg configuration to use
449 * @param callback Function to call with the requested data.
450 * @param callback_cls Closure for @c callback.
451 * @return NULL on error
453 struct GNUNET_CADET_PeersLister *
454 GNUNET_CADET_list_peers (const struct GNUNET_CONFIGURATION_Handle *cfg,
455 GNUNET_CADET_PeersCB callback,
460 * Cancel a peer info request. The callback will not be called (anymore).
462 * @param pl operation handle
463 * @return Closure that was given to #GNUNET_CADET_list_peers().
466 GNUNET_CADET_list_peers_cancel (struct GNUNET_CADET_PeersLister *pl);
470 * Detailed information we return per peer.
472 struct GNUNET_CADET_PeerPathDetail
475 * Peer this is about.
477 struct GNUNET_PeerIdentity peer;
480 * Offset of the target peer on the @e path.
482 unsigned int target_offset;
485 * Number of entries on the @e path.
487 unsigned int path_length;
490 * Array of PEER_IDs representing all paths to reach the peer. Each
491 * path starts with the first hop (local peer not included). Each
492 * path ends with the destination peer (given in @e peer).
494 const struct GNUNET_PeerIdentity *path;
499 * Method called to retrieve information about a specific path
500 * known to the service.
502 * @param cls Closure.
503 * @param ppd details about a path to the peer, NULL for end of information
505 typedef void (*GNUNET_CADET_PathCB) (
507 const struct GNUNET_CADET_PeerPathDetail *ppd);
511 * Handle to cancel #GNUNET_CADET_get_path() operation.
513 struct GNUNET_CADET_GetPath;
517 * Request information about a peer known to the running cadet peer.
519 * @param cfg configuration to use
520 * @param id Peer whose paths we want to examine.
521 * @param callback Function to call with the requested data.
522 * @param callback_cls Closure for @c callback.
523 * @return NULL on error
525 struct GNUNET_CADET_GetPath *
526 GNUNET_CADET_get_path (const struct GNUNET_CONFIGURATION_Handle *cfg,
527 const struct GNUNET_PeerIdentity *id,
528 GNUNET_CADET_PathCB callback,
533 * Cancel @a gp operation.
535 * @param gp operation to cancel
536 * @return closure from #GNUNET_CADET_get_path().
539 GNUNET_CADET_get_path_cancel (struct GNUNET_CADET_GetPath *gp);
543 * Details about a tunnel managed by CADET.
545 struct GNUNET_CADET_TunnelDetails
548 * Target of the tunnel.
550 struct GNUNET_PeerIdentity peer;
553 * How many channels use the tunnel.
558 * How many connections support the tunnel.
560 uint32_t connections;
563 * What is our encryption state?
568 * What is our connectivity state?
575 * Method called to retrieve information about all tunnels in CADET, called
578 * After last tunnel has been reported, an additional call with NULL is done.
580 * @param cls Closure.
581 * @param td tunnel details, NULL for end of list
583 typedef void (*GNUNET_CADET_TunnelsCB) (
585 const struct GNUNET_CADET_TunnelDetails *td);
591 struct GNUNET_CADET_ListTunnels;
595 * Request information about tunnels of the running cadet peer.
596 * The callback will be called for every tunnel of the service.
597 * Only one info request (of any kind) can be active at once.
599 * @param cfg configuration to use
600 * @param callback Function to call with the requested data.
601 * @param callback_cls Closure for @c callback.
602 * @return NULL on error
604 struct GNUNET_CADET_ListTunnels *
605 GNUNET_CADET_list_tunnels (const struct GNUNET_CONFIGURATION_Handle *cfg,
606 GNUNET_CADET_TunnelsCB callback,
611 * Cancel a monitor request. The monitor callback will not be called.
613 * @param lt operation handle
614 * @return Closure given to #GNUNET_CADET_list_tunnels(), if any.
617 GNUNET_CADET_list_tunnels_cancel (struct GNUNET_CADET_ListTunnels *lt);
620 #if 0 /* keep Emacsens' auto-indent happy */
627 /* ifndef GNUNET_CADET_SERVICE_H */
630 /** @} */ /* end of group */
632 /* end of gnunet_cadet_service.h */