2 This file is part of GNUnet.
3 Copyright (C) 2009-2014 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 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
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 Boston, MA 02110-1301, USA.
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
31 * - [CADET documentation](https://gnunet.org/cadet-subsystem)
32 * - [CADET paper](https://gnunet.org/cadet)
36 #ifndef GNUNET_CADET_SERVICE_H
37 #define GNUNET_CADET_SERVICE_H
42 #if 0 /* keep Emacsens' auto-indent happy */
47 #include "gnunet_util_lib.h"
48 #include "gnunet_transport_service.h"
51 * Version number of GNUnet-cadet API.
53 #define GNUNET_CADET_VERSION 0x00000003
57 * Opaque handle to the service.
59 struct GNUNET_CADET_Handle;
62 * Opaque handle to a channel.
64 struct GNUNET_CADET_Channel;
67 * Hash to be used in Cadet communication. Only 256 bits needed,
68 * instead of the 512 from `struct GNUNET_HashCode`.
70 struct GNUNET_CADET_Hash
72 unsigned char bits[256 / 8];
77 * Channel options. Second line indicates filed in the
78 * CadetChannelInfo union carrying the answer.
80 enum GNUNET_CADET_ChannelOption
83 * Default options: unreliable, default buffering, not out of order.
85 GNUNET_CADET_OPTION_DEFAULT = 0x0,
88 * Disable buffering on intermediate nodes (for minimum latency).
91 GNUNET_CADET_OPTION_NOBUFFER = 0x1,
94 * Enable channel reliability, lost messages will be retransmitted.
97 GNUNET_CADET_OPTION_RELIABLE = 0x2,
100 * Enable out of order delivery of messages.
103 GNUNET_CADET_OPTION_OOORDER = 0x4,
106 * Who is the peer at the other end of the channel.
107 * Only for use in @c GNUNET_CADET_channel_get_info
108 * struct GNUNET_PeerIdentity *peer
110 GNUNET_CADET_OPTION_PEER = 0x8
116 * Functions with this signature are called whenever a message is
119 * Each time the function must call #GNUNET_CADET_receive_done on the channel
120 * in order to receive the next message. This doesn't need to be immediate:
121 * can be delayed if some processing is done on the message.
123 * @param cls Closure (set from #GNUNET_CADET_connect).
124 * @param channel Connection to the other end.
125 * @param channel_ctx Place to store local state associated with the channel.
126 * @param message The actual message.
127 * @return #GNUNET_OK to keep the channel open,
128 * #GNUNET_SYSERR to close it (signal serious error).
131 (*GNUNET_CADET_MessageCallback) (void *cls,
132 struct GNUNET_CADET_Channel *channel,
134 const struct GNUNET_MessageHeader *message);
138 * Message handler. Each struct specifies how to handle on particular
139 * type of message received.
141 struct GNUNET_CADET_MessageHandler
144 * Function to call for messages of type @e type.
146 GNUNET_CADET_MessageCallback callback;
149 * Type of the message this handler covers.
154 * Expected size of messages of this type. Use 0 for variable-size.
155 * If non-zero, messages of the given type will be discarded if they
156 * do not have the right size.
158 uint16_t expected_size;
163 * Method called whenever another peer has added us to a channel
164 * the other peer initiated.
165 * Only called (once) upon reception of data with a message type which was
166 * subscribed to in #GNUNET_CADET_connect.
168 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
169 * this case the handler MUST return NULL.
172 * @param channel new handle to the channel
173 * @param initiator peer that started the channel
174 * @param port Port this channel is for.
175 * @param options CadetOption flag field, with all active option bits set to 1.
177 * @return initial channel context for the channel
178 * (can be NULL -- that's not an error)
181 (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
182 struct GNUNET_CADET_Channel *channel,
183 const struct GNUNET_PeerIdentity *initiator,
185 enum GNUNET_CADET_ChannelOption options);
189 * Function called whenever a channel is destroyed. Should clean up
190 * any associated state, including cancelling any pending transmission on this
193 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
195 * @param cls closure (set from #GNUNET_CADET_connect)
196 * @param channel connection to the other end (henceforth invalid)
197 * @param channel_ctx place where local state associated
198 * with the channel is stored
201 (GNUNET_CADET_ChannelEndHandler) (void *cls,
202 const struct GNUNET_CADET_Channel *channel,
207 * Connect to the cadet service.
209 * @param cfg Configuration to use.
210 * @param cls Closure for the various callbacks that follow (including
211 * handlers in the handlers array).
212 * @param new_channel Function called when an *incoming* channel is created.
213 * Can be NULL if no inbound channels are desired.
215 * @param cleaner Function called when a channel is destroyed.
216 * It is called immediately if #GNUNET_CADET_channel_destroy
217 * is called on the channel.
218 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
219 * one must call #GNUNET_CADET_receive_done on the channel to
220 * receive the next message. Messages of a type that is not
221 * in the handlers array are ignored if received.
222 * @param ports NULL or 0-terminated array of port numbers for incoming channels.
223 * See @a new_channel.
225 * @return handle to the cadet service NULL on error
226 * (in this case, init is never called)
228 struct GNUNET_CADET_Handle *
229 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
231 GNUNET_CADET_InboundChannelNotificationHandler new_channel,
232 GNUNET_CADET_ChannelEndHandler cleaner,
233 const struct GNUNET_CADET_MessageHandler *handlers,
234 const uint32_t *ports);
238 * Disconnect from the cadet service. All channels will be destroyed. All channel
239 * disconnect callbacks will be called on any still connected peers, notifying
240 * about their disconnection. The registered inbound channel cleaner will be
241 * called should any inbound channels still exist.
243 * @param handle connection to cadet to disconnect
246 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
250 * Create a new channel towards a remote peer.
252 * If the destination port is not open by any peer or the destination peer
253 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
256 * @param h cadet handle
257 * @param channel_ctx client's channel context to associate with the channel
258 * @param peer peer identity the channel should go to
259 * @param port Port number.
260 * @param options CadetOption flag field, with all desired option bits set to 1.
262 * @return handle to the channel
264 struct GNUNET_CADET_Channel *
265 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
267 const struct GNUNET_PeerIdentity *peer,
269 enum GNUNET_CADET_ChannelOption options);
273 * Destroy an existing channel.
275 * The existing end callback for the channel will be called immediately.
276 * Any pending outgoing messages will be sent but no incoming messages will be
277 * accepted and no data callbacks will be called.
279 * @param channel Channel handle, becomes invalid after this call.
282 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
286 * Struct to retrieve info about a channel.
288 union GNUNET_CADET_ChannelInfo
292 * #GNUNET_YES / #GNUNET_NO, for binary flags.
297 * Peer on the other side of the channel
299 const struct GNUNET_PeerIdentity peer;
304 * Get information about a channel.
306 * @param channel Channel handle.
307 * @param option Query type GNUNET_CADET_OPTION_*
308 * @param ... dependant on option, currently not used
309 * @return Union with an answer to the query.
311 const union GNUNET_CADET_ChannelInfo *
312 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
313 enum GNUNET_CADET_ChannelOption option, ...);
317 * Handle for a transmission request.
319 struct GNUNET_CADET_TransmitHandle;
323 * Ask the cadet to call @a notify once it is ready to transmit the
324 * given number of bytes to the specified channel.
325 * Only one call can be active at any time, to issue another request,
326 * wait for the callback or cancel the current request.
328 * @param channel channel to use for transmission
329 * @param cork is corking allowed for this transmission?
330 * @param maxdelay how long can the message wait?
331 * @param notify_size how many bytes of buffer space does notify want?
332 * @param notify function to call when buffer space is available;
333 * will be called with NULL on timeout or if the overall queue
334 * for this peer is larger than queue_size and this is currently
335 * the message with the lowest priority
336 * @param notify_cls closure for @a notify
337 * @return non-NULL if the notify callback was queued,
338 * NULL if we can not even queue the request (insufficient
339 * memory); if NULL is returned, @a notify will NOT be called.
341 struct GNUNET_CADET_TransmitHandle *
342 GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
344 struct GNUNET_TIME_Relative maxdelay,
346 GNUNET_CONNECTION_TransmitReadyNotify notify,
351 * Cancel the specified transmission-ready notification.
353 * @param th handle that was returned by "notify_transmit_ready".
356 GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);
360 * Indicate readiness to receive the next message on a channel.
362 * Should only be called once per handler called.
364 * @param channel Channel that will be allowed to call another handler.
367 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
371 /******************************************************************************/
372 /******************** MONITORING /DEBUG API *************************/
373 /******************************************************************************/
374 /* The following calls are not useful for normal CADET operation, but for */
375 /* debug and monitoring of the cadet state. They can be safely ignored. */
376 /* The API can change at any point without notice. */
377 /* Please contact the developer if you consider any of this calls useful for */
378 /* normal cadet applications. */
379 /******************************************************************************/
383 * Method called to retrieve information about a specific channel the cadet peer
384 * is aware of, including all transit nodes.
386 * @param cls Closure.
387 * @param root Root of the channel.
388 * @param dest Destination of the channel.
389 * @param port Destination port of the channel.
390 * @param root_channel_number Local number for root, if known.
391 * @param dest_channel_number Local number for dest, if known.
392 * @param public_channel_numbe Number for P2P, always known.
395 (*GNUNET_CADET_ChannelCB) (void *cls,
396 const struct GNUNET_PeerIdentity *root,
397 const struct GNUNET_PeerIdentity *dest,
399 uint32_t root_channel_number,
400 uint32_t dest_channel_number,
401 uint32_t public_channel_number);
404 * Method called to retrieve information about all peers in CADET, called
407 * After last peer has been reported, an additional call with NULL is done.
409 * @param cls Closure.
410 * @param peer Peer, or NULL on "EOF".
411 * @param tunnel Do we have a tunnel towards this peer?
412 * @param n_paths Number of known paths towards this peer.
413 * @param best_path How long is the best path?
414 * (0 = unknown, 1 = ourselves, 2 = neighbor)
417 (*GNUNET_CADET_PeersCB) (void *cls,
418 const struct GNUNET_PeerIdentity *peer,
420 unsigned int n_paths,
421 unsigned int best_path);
424 * Method called to retrieve information about a specific peer
425 * known to the service.
427 * @param cls Closure.
428 * @param peer Peer ID.
429 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
430 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
431 * @param n_paths Number of paths known towards peer.
432 * @param paths Array of PEER_IDs representing all paths to reach the peer.
433 * Each path starts with the first hop (local peer not included).
434 * Each path ends with the destination peer (given in @c peer).
437 (*GNUNET_CADET_PeerCB) (void *cls,
438 const struct GNUNET_PeerIdentity *peer,
441 unsigned int n_paths,
442 struct GNUNET_PeerIdentity *paths);
446 * Method called to retrieve information about all tunnels in CADET, called
449 * After last tunnel has been reported, an additional call with NULL is done.
451 * @param cls Closure.
452 * @param peer Destination peer, or NULL on "EOF".
453 * @param channels Number of channels.
454 * @param connections Number of connections.
455 * @param estate Encryption state.
456 * @param cstate Connectivity state.
459 (*GNUNET_CADET_TunnelsCB) (void *cls,
460 const struct GNUNET_PeerIdentity *peer,
461 unsigned int channels,
462 unsigned int connections,
468 * Method called to retrieve information about a specific tunnel the cadet peer
469 * has established, o`r is trying to establish.
471 * @param cls Closure.
472 * @param peer Peer towards whom the tunnel is directed.
473 * @param n_channels Number of channels.
474 * @param n_connections Number of connections.
475 * @param channels Channels.
476 * @param connections Connections.
477 * @param estate Encryption state.
478 * @param cstate Connectivity state.
481 (*GNUNET_CADET_TunnelCB) (void *cls,
482 const struct GNUNET_PeerIdentity *peer,
483 unsigned int n_channels,
484 unsigned int n_connections,
486 struct GNUNET_CADET_Hash *connections,
488 unsigned int cstate);
492 * Request information about a specific channel of the running cadet peer.
494 * WARNING: unstable API, likely to change in the future!
496 * @param h Handle to the cadet peer.
497 * @param peer ID of the other end of the channel.
498 * @param channel_number Channel number.
499 * @param callback Function to call with the requested data.
500 * @param callback_cls Closure for @c callback.
503 GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
504 struct GNUNET_PeerIdentity *peer,
505 uint32_t channel_number,
506 GNUNET_CADET_ChannelCB callback,
511 * Request a debug dump on the service's STDERR.
513 * WARNING: unstable API, likely to change in the future!
515 * @param h cadet handle
518 GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);
522 * Request information about peers known to the running cadet service.
523 * The callback will be called for every peer known to the service.
524 * Only one info request (of any kind) can be active at once.
527 * WARNING: unstable API, likely to change in the future!
529 * @param h Handle to the cadet peer.
530 * @param callback Function to call with the requested data.
531 * @param callback_cls Closure for @c callback.
533 * @return #GNUNET_OK / #GNUNET_SYSERR
536 GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
537 GNUNET_CADET_PeersCB callback,
542 * Cancel a peer info request. The callback will not be called (anymore).
544 * WARNING: unstable API, likely to change in the future!
546 * @param h Cadet handle.
548 * @return Closure that was given to #GNUNET_CADET_get_peers().
551 GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);
555 * Request information about a peer known to the running cadet peer.
556 * The callback will be called for the tunnel once.
557 * Only one info request (of any kind) can be active at once.
559 * WARNING: unstable API, likely to change in the future!
561 * @param h Handle to the cadet peer.
562 * @param id Peer whose tunnel to examine.
563 * @param callback Function to call with the requested data.
564 * @param callback_cls Closure for @c callback.
566 * @return #GNUNET_OK / #GNUNET_SYSERR
569 GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
570 const struct GNUNET_PeerIdentity *id,
571 GNUNET_CADET_PeerCB callback,
576 * Request information about tunnels of the running cadet peer.
577 * The callback will be called for every tunnel of the service.
578 * Only one info request (of any kind) can be active at once.
580 * WARNING: unstable API, likely to change in the future!
582 * @param h Handle to the cadet peer.
583 * @param callback Function to call with the requested data.
584 * @param callback_cls Closure for @c callback.
586 * @return #GNUNET_OK / #GNUNET_SYSERR
589 GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
590 GNUNET_CADET_TunnelsCB callback,
595 * Cancel a monitor request. The monitor callback will not be called.
597 * @param h Cadet handle.
599 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
602 GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);
606 * Request information about a tunnel of the running cadet peer.
607 * The callback will be called for the tunnel once.
608 * Only one info request (of any kind) can be active at once.
610 * WARNING: unstable API, likely to change in the future!
612 * @param h Handle to the cadet peer.
613 * @param id Peer whose tunnel to examine.
614 * @param callback Function to call with the requested data.
615 * @param callback_cls Closure for @c callback.
617 * @return #GNUNET_OK / #GNUNET_SYSERR
620 GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
621 const struct GNUNET_PeerIdentity *id,
622 GNUNET_CADET_TunnelCB callback,
627 * Create a message queue for a cadet channel.
628 * The message queue can only be used to transmit messages,
629 * not to receive them.
631 * @param channel the channel to create the message qeue for
632 * @return a message queue to messages over the channel
634 struct GNUNET_MQ_Handle *
635 GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);
638 #if 0 /* keep Emacsens' auto-indent happy */
645 /** @} */ /* end of group */
647 /* ifndef GNUNET_CADET_SERVICE_H */
649 /* end of gnunet_cadet_service.h */