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3 Copyright (C) 2009-2014 GNUnet e.V.
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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
41 #if 0 /* keep Emacsens' auto-indent happy */
46 #include "gnunet_util_lib.h"
47 #include "gnunet_transport_service.h"
50 * Version number of GNUnet-cadet API.
52 #define GNUNET_CADET_VERSION 0x00000003
56 * Opaque handle to the service.
58 struct GNUNET_CADET_Handle;
61 * Opaque handle to a channel.
63 struct GNUNET_CADET_Channel;
66 * Hash to be used in Cadet communication. Only 256 bits needed,
67 * instead of the 512 from `struct GNUNET_HashCode`.
69 struct GNUNET_CADET_Hash
71 unsigned char bits[256 / 8];
76 * Channel options. Second line indicates filed in the
77 * CadetChannelInfo union carrying the answer.
79 enum GNUNET_CADET_ChannelOption
82 * Default options: unreliable, default buffering, not out of order.
84 GNUNET_CADET_OPTION_DEFAULT = 0x0,
87 * Disable buffering on intermediate nodes (for minimum latency).
90 GNUNET_CADET_OPTION_NOBUFFER = 0x1,
93 * Enable channel reliability, lost messages will be retransmitted.
96 GNUNET_CADET_OPTION_RELIABLE = 0x2,
99 * Enable out of order delivery of messages.
102 GNUNET_CADET_OPTION_OOORDER = 0x4,
105 * Who is the peer at the other end of the channel.
106 * Only for use in @c GNUNET_CADET_channel_get_info
107 * struct GNUNET_PeerIdentity *peer
109 GNUNET_CADET_OPTION_PEER = 0x8
115 * Functions with this signature are called whenever a message is
118 * Each time the function must call #GNUNET_CADET_receive_done on the channel
119 * in order to receive the next message. This doesn't need to be immediate:
120 * can be delayed if some processing is done on the message.
122 * @param cls Closure (set from #GNUNET_CADET_connect).
123 * @param channel Connection to the other end.
124 * @param channel_ctx Place to store local state associated with the channel.
125 * @param message The actual message.
126 * @return #GNUNET_OK to keep the channel open,
127 * #GNUNET_SYSERR to close it (signal serious error).
130 (*GNUNET_CADET_MessageCallback) (void *cls,
131 struct GNUNET_CADET_Channel *channel,
133 const struct GNUNET_MessageHeader *message);
137 * Message handler. Each struct specifies how to handle on particular
138 * type of message received.
140 struct GNUNET_CADET_MessageHandler
143 * Function to call for messages of type @e type.
145 GNUNET_CADET_MessageCallback callback;
148 * Type of the message this handler covers.
153 * Expected size of messages of this type. Use 0 for variable-size.
154 * If non-zero, messages of the given type will be discarded if they
155 * do not have the right size.
157 uint16_t expected_size;
162 * Method called whenever another peer has added us to a channel
163 * the other peer initiated.
164 * Only called (once) upon reception of data with a message type which was
165 * subscribed to in #GNUNET_CADET_connect.
167 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
168 * this case the handler MUST return NULL.
171 * @param channel new handle to the channel
172 * @param initiator peer that started the channel
173 * @param port Port this channel is for.
174 * @param options CadetOption flag field, with all active option bits set to 1.
176 * @return initial channel context for the channel
177 * (can be NULL -- that's not an error)
180 (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
181 struct GNUNET_CADET_Channel *channel,
182 const struct GNUNET_PeerIdentity *initiator,
184 enum GNUNET_CADET_ChannelOption options);
188 * Function called whenever a channel is destroyed. Should clean up
189 * any associated state, including cancelling any pending transmission on this
192 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
194 * @param cls closure (set from #GNUNET_CADET_connect)
195 * @param channel connection to the other end (henceforth invalid)
196 * @param channel_ctx place where local state associated
197 * with the channel is stored
200 (GNUNET_CADET_ChannelEndHandler) (void *cls,
201 const struct GNUNET_CADET_Channel *channel,
206 * Connect to the cadet service.
208 * @param cfg Configuration to use.
209 * @param cls Closure for the various callbacks that follow (including
210 * handlers in the handlers array).
211 * @param new_channel Function called when an *incoming* channel is created.
212 * Can be NULL if no inbound channels are desired.
214 * @param cleaner Function called when a channel is destroyed.
215 * It is called immediately if #GNUNET_CADET_channel_destroy
216 * is called on the channel.
217 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
218 * one must call #GNUNET_CADET_receive_done on the channel to
219 * receive the next message. Messages of a type that is not
220 * in the handlers array are ignored if received.
221 * @param ports NULL or 0-terminated array of port numbers for incoming channels.
222 * See @a new_channel.
224 * @return handle to the cadet service NULL on error
225 * (in this case, init is never called)
227 struct GNUNET_CADET_Handle *
228 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
230 GNUNET_CADET_InboundChannelNotificationHandler new_channel,
231 GNUNET_CADET_ChannelEndHandler cleaner,
232 const struct GNUNET_CADET_MessageHandler *handlers,
233 const uint32_t *ports);
237 * Disconnect from the cadet service. All channels will be destroyed. All channel
238 * disconnect callbacks will be called on any still connected peers, notifying
239 * about their disconnection. The registered inbound channel cleaner will be
240 * called should any inbound channels still exist.
242 * @param handle connection to cadet to disconnect
245 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
249 * Create a new channel towards a remote peer.
251 * If the destination port is not open by any peer or the destination peer
252 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
255 * @param h cadet handle
256 * @param channel_ctx client's channel context to associate with the channel
257 * @param peer peer identity the channel should go to
258 * @param port Port number.
259 * @param options CadetOption flag field, with all desired option bits set to 1.
261 * @return handle to the channel
263 struct GNUNET_CADET_Channel *
264 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
266 const struct GNUNET_PeerIdentity *peer,
268 enum GNUNET_CADET_ChannelOption options);
272 * Destroy an existing channel.
274 * The existing end callback for the channel will be called immediately.
275 * Any pending outgoing messages will be sent but no incoming messages will be
276 * accepted and no data callbacks will be called.
278 * @param channel Channel handle, becomes invalid after this call.
281 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
285 * Struct to retrieve info about a channel.
287 union GNUNET_CADET_ChannelInfo
291 * #GNUNET_YES / #GNUNET_NO, for binary flags.
296 * Peer on the other side of the channel
298 const struct GNUNET_PeerIdentity peer;
303 * Get information about a channel.
305 * @param channel Channel handle.
306 * @param option Query type GNUNET_CADET_OPTION_*
307 * @param ... dependant on option, currently not used
308 * @return Union with an answer to the query.
310 const union GNUNET_CADET_ChannelInfo *
311 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
312 enum GNUNET_CADET_ChannelOption option, ...);
316 * Handle for a transmission request.
318 struct GNUNET_CADET_TransmitHandle;
322 * Ask the cadet to call @a notify once it is ready to transmit the
323 * given number of bytes to the specified channel.
324 * Only one call can be active at any time, to issue another request,
325 * wait for the callback or cancel the current request.
327 * @param channel channel to use for transmission
328 * @param cork is corking allowed for this transmission?
329 * @param maxdelay how long can the message wait?
330 * @param notify_size how many bytes of buffer space does notify want?
331 * @param notify function to call when buffer space is available;
332 * will be called with NULL on timeout or if the overall queue
333 * for this peer is larger than queue_size and this is currently
334 * the message with the lowest priority
335 * @param notify_cls closure for @a notify
336 * @return non-NULL if the notify callback was queued,
337 * NULL if we can not even queue the request (insufficient
338 * memory); if NULL is returned, @a notify will NOT be called.
340 struct GNUNET_CADET_TransmitHandle *
341 GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
343 struct GNUNET_TIME_Relative maxdelay,
345 GNUNET_CONNECTION_TransmitReadyNotify notify,
350 * Cancel the specified transmission-ready notification.
352 * @param th handle that was returned by "notify_transmit_ready".
355 GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);
359 * Indicate readiness to receive the next message on a channel.
361 * Should only be called once per handler called.
363 * @param channel Channel that will be allowed to call another handler.
366 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
370 /******************************************************************************/
371 /******************** MONITORING /DEBUG API *************************/
372 /******************************************************************************/
373 /* The following calls are not useful for normal CADET operation, but for */
374 /* debug and monitoring of the cadet state. They can be safely ignored. */
375 /* The API can change at any point without notice. */
376 /* Please contact the developer if you consider any of this calls useful for */
377 /* normal cadet applications. */
378 /******************************************************************************/
382 * Method called to retrieve information about a specific channel the cadet peer
383 * is aware of, including all transit nodes.
385 * @param cls Closure.
386 * @param root Root of the channel.
387 * @param dest Destination of the channel.
388 * @param port Destination port of the channel.
389 * @param root_channel_number Local number for root, if known.
390 * @param dest_channel_number Local number for dest, if known.
391 * @param public_channel_numbe Number for P2P, always known.
394 (*GNUNET_CADET_ChannelCB) (void *cls,
395 const struct GNUNET_PeerIdentity *root,
396 const struct GNUNET_PeerIdentity *dest,
398 uint32_t root_channel_number,
399 uint32_t dest_channel_number,
400 uint32_t public_channel_number);
403 * Method called to retrieve information about all peers in CADET, called
406 * After last peer has been reported, an additional call with NULL is done.
408 * @param cls Closure.
409 * @param peer Peer, or NULL on "EOF".
410 * @param tunnel Do we have a tunnel towards this peer?
411 * @param n_paths Number of known paths towards this peer.
412 * @param best_path How long is the best path?
413 * (0 = unknown, 1 = ourselves, 2 = neighbor)
416 (*GNUNET_CADET_PeersCB) (void *cls,
417 const struct GNUNET_PeerIdentity *peer,
419 unsigned int n_paths,
420 unsigned int best_path);
423 * Method called to retrieve information about a specific peer
424 * known to the service.
426 * @param cls Closure.
427 * @param peer Peer ID.
428 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
429 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
430 * @param n_paths Number of paths known towards peer.
431 * @param paths Array of PEER_IDs representing all paths to reach the peer.
432 * Each path starts with the first hop (local peer not included).
433 * Each path ends with the destination peer (given in @c peer).
436 (*GNUNET_CADET_PeerCB) (void *cls,
437 const struct GNUNET_PeerIdentity *peer,
440 unsigned int n_paths,
441 struct GNUNET_PeerIdentity *paths);
445 * Method called to retrieve information about all tunnels in CADET, called
448 * After last tunnel has been reported, an additional call with NULL is done.
450 * @param cls Closure.
451 * @param peer Destination peer, or NULL on "EOF".
452 * @param channels Number of channels.
453 * @param connections Number of connections.
454 * @param estate Encryption state.
455 * @param cstate Connectivity state.
458 (*GNUNET_CADET_TunnelsCB) (void *cls,
459 const struct GNUNET_PeerIdentity *peer,
460 unsigned int channels,
461 unsigned int connections,
467 * Method called to retrieve information about a specific tunnel the cadet peer
468 * has established, o`r is trying to establish.
470 * @param cls Closure.
471 * @param peer Peer towards whom the tunnel is directed.
472 * @param n_channels Number of channels.
473 * @param n_connections Number of connections.
474 * @param channels Channels.
475 * @param connections Connections.
476 * @param estate Encryption state.
477 * @param cstate Connectivity state.
480 (*GNUNET_CADET_TunnelCB) (void *cls,
481 const struct GNUNET_PeerIdentity *peer,
482 unsigned int n_channels,
483 unsigned int n_connections,
485 struct GNUNET_CADET_Hash *connections,
487 unsigned int cstate);
491 * Request information about a specific channel of the running cadet peer.
493 * WARNING: unstable API, likely to change in the future!
495 * @param h Handle to the cadet peer.
496 * @param peer ID of the other end of the channel.
497 * @param channel_number Channel number.
498 * @param callback Function to call with the requested data.
499 * @param callback_cls Closure for @c callback.
502 GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
503 struct GNUNET_PeerIdentity *peer,
504 uint32_t channel_number,
505 GNUNET_CADET_ChannelCB callback,
510 * Request a debug dump on the service's STDERR.
512 * WARNING: unstable API, likely to change in the future!
514 * @param h cadet handle
517 GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);
521 * Request information about peers known to the running cadet service.
522 * The callback will be called for every peer known to the service.
523 * Only one info request (of any kind) can be active at once.
526 * WARNING: unstable API, likely to change in the future!
528 * @param h Handle to the cadet peer.
529 * @param callback Function to call with the requested data.
530 * @param callback_cls Closure for @c callback.
532 * @return #GNUNET_OK / #GNUNET_SYSERR
535 GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
536 GNUNET_CADET_PeersCB callback,
541 * Cancel a peer info request. The callback will not be called (anymore).
543 * WARNING: unstable API, likely to change in the future!
545 * @param h Cadet handle.
547 * @return Closure that was given to #GNUNET_CADET_get_peers().
550 GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);
554 * Request information about a peer known to the running cadet peer.
555 * The callback will be called for the tunnel once.
556 * Only one info request (of any kind) can be active at once.
558 * WARNING: unstable API, likely to change in the future!
560 * @param h Handle to the cadet peer.
561 * @param id Peer whose tunnel to examine.
562 * @param callback Function to call with the requested data.
563 * @param callback_cls Closure for @c callback.
565 * @return #GNUNET_OK / #GNUNET_SYSERR
568 GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
569 const struct GNUNET_PeerIdentity *id,
570 GNUNET_CADET_PeerCB callback,
575 * Request information about tunnels of the running cadet peer.
576 * The callback will be called for every tunnel of the service.
577 * Only one info request (of any kind) can be active at once.
579 * WARNING: unstable API, likely to change in the future!
581 * @param h Handle to the cadet peer.
582 * @param callback Function to call with the requested data.
583 * @param callback_cls Closure for @c callback.
585 * @return #GNUNET_OK / #GNUNET_SYSERR
588 GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
589 GNUNET_CADET_TunnelsCB callback,
594 * Cancel a monitor request. The monitor callback will not be called.
596 * @param h Cadet handle.
598 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
601 GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);
605 * Request information about a tunnel of the running cadet peer.
606 * The callback will be called for the tunnel once.
607 * Only one info request (of any kind) can be active at once.
609 * WARNING: unstable API, likely to change in the future!
611 * @param h Handle to the cadet peer.
612 * @param id Peer whose tunnel to examine.
613 * @param callback Function to call with the requested data.
614 * @param callback_cls Closure for @c callback.
616 * @return #GNUNET_OK / #GNUNET_SYSERR
619 GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
620 const struct GNUNET_PeerIdentity *id,
621 GNUNET_CADET_TunnelCB callback,
626 * Create a message queue for a cadet channel.
627 * The message queue can only be used to transmit messages,
628 * not to receive them.
630 * @param channel the channel to create the message qeue for
631 * @return a message queue to messages over the channel
633 struct GNUNET_MQ_Handle *
634 GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);
637 #if 0 /* keep Emacsens' auto-indent happy */
644 /* ifndef GNUNET_CADET_SERVICE_H */
647 /** @} */ /* end of group */
649 /* end of gnunet_cadet_service.h */