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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 0x00000004
56 * Opaque handle to the service.
58 struct GNUNET_CADET_Handle;
61 * Opaque handle to a channel.
63 struct GNUNET_CADET_Channel;
66 * Opaque handle to a port.
68 struct GNUNET_CADET_Port;
71 * Hash to be used in Cadet communication. Only 256 bits needed,
72 * instead of the 512 from `struct GNUNET_HashCode`.
74 struct GNUNET_CADET_Hash
76 unsigned char bits[256 / 8];
81 * Channel options. Second line indicates filed in the
82 * CadetChannelInfo union carrying the answer.
84 enum GNUNET_CADET_ChannelOption
87 * Default options: unreliable, default buffering, not out of order.
89 GNUNET_CADET_OPTION_DEFAULT = 0x0,
92 * Disable buffering on intermediate nodes (for minimum latency).
95 GNUNET_CADET_OPTION_NOBUFFER = 0x1,
98 * Enable channel reliability, lost messages will be retransmitted.
101 GNUNET_CADET_OPTION_RELIABLE = 0x2,
104 * Enable out of order delivery of messages.
105 * Set bit for out-of-order delivery.
107 GNUNET_CADET_OPTION_OUT_OF_ORDER = 0x4,
110 * Who is the peer at the other end of the channel.
111 * Only for use in @c GNUNET_CADET_channel_get_info
112 * struct GNUNET_PeerIdentity *peer
114 GNUNET_CADET_OPTION_PEER = 0x8
120 * Functions with this signature are called whenever a message is
123 * Each time the function must call #GNUNET_CADET_receive_done on the channel
124 * in order to receive the next message. This doesn't need to be immediate:
125 * can be delayed if some processing is done on the message.
127 * @param cls Closure (set from #GNUNET_CADET_connect).
128 * @param channel Connection to the other end.
129 * @param channel_ctx Place to store local state associated with the channel.
130 * @param message The actual message.
131 * @return #GNUNET_OK to keep the channel open,
132 * #GNUNET_SYSERR to close it (signal serious error).
135 (*GNUNET_CADET_MessageCallback) (void *cls,
136 struct GNUNET_CADET_Channel *channel,
138 const struct GNUNET_MessageHeader *message);
142 * Message handler. Each struct specifies how to handle on particular
143 * type of message received.
145 struct GNUNET_CADET_MessageHandler
148 * Function to call for messages of type @e type.
150 GNUNET_CADET_MessageCallback callback;
153 * Type of the message this handler covers.
158 * Expected size of messages of this type. Use 0 for variable-size.
159 * If non-zero, messages of the given type will be discarded if they
160 * do not have the right size.
162 uint16_t expected_size;
167 * Method called whenever another peer has added us to a channel
168 * the other peer initiated.
169 * Only called (once) upon reception of data with a message type which was
170 * subscribed to in #GNUNET_CADET_connect.
172 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
173 * this case the handler MUST return NULL.
176 * @param channel new handle to the channel
177 * @param initiator peer that started the channel
178 * @param port Port this channel is for.
179 * @param options CadetOption flag field, with all active option bits set to 1.
181 * @return initial channel context for the channel
182 * (can be NULL -- that's not an error)
185 (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
186 struct GNUNET_CADET_Channel *channel,
187 const struct GNUNET_PeerIdentity *initiator,
188 const struct GNUNET_HashCode *port,
189 enum GNUNET_CADET_ChannelOption options);
193 * Function called whenever a channel is destroyed. Should clean up
194 * any associated state, including cancelling any pending transmission on this
197 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
199 * @param cls closure (set from #GNUNET_CADET_connect)
200 * @param channel connection to the other end (henceforth invalid)
201 * @param channel_ctx place where local state associated
202 * with the channel is stored
205 (GNUNET_CADET_ChannelEndHandler) (void *cls,
206 const struct GNUNET_CADET_Channel *channel,
211 * Connect to the cadet service.
213 * @param cfg Configuration to use.
214 * @param cls Closure for the various callbacks that follow (including
215 * handlers in the handlers array).
216 * @param cleaner Function called when a channel is destroyed.
217 * It is called immediately if #GNUNET_CADET_channel_destroy
218 * is called on the channel.
219 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
220 * one must call #GNUNET_CADET_receive_done on the channel to
221 * receive the next message. Messages of a type that is not
222 * in the handlers array are ignored if received.
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_ChannelEndHandler cleaner,
231 const struct GNUNET_CADET_MessageHandler *handlers);
235 * Disconnect from the cadet service. All channels will be destroyed. All channel
236 * disconnect callbacks will be called on any still connected peers, notifying
237 * about their disconnection. The registered inbound channel cleaner will be
238 * called should any inbound channels still exist.
240 * @param handle connection to cadet to disconnect
243 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
246 * Open a port to receive incomming channels.
248 * @param h CADET handle.
249 * @param port Hash representing the port number.
250 * @param new_channel Function called when an channel is received.
251 * @param new_channel_cls Closure for @a new_channel.
253 * @return Port handle.
255 struct GNUNET_CADET_Port *
256 GNUNET_CADET_open_port (struct GNUNET_CADET_Handle *h,
257 const struct GNUNET_HashCode *port,
258 GNUNET_CADET_InboundChannelNotificationHandler
260 void *new_channel_cls);
263 * Close a port opened with @a GNUNET_CADET_open_port.
264 * The @a new_channel callback will no longer be called.
266 * @param p Port handle.
269 GNUNET_CADET_close_port (struct GNUNET_CADET_Port *p);
272 * Create a new channel towards a remote peer.
274 * If the destination port is not open by any peer or the destination peer
275 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
278 * @param h cadet handle
279 * @param channel_ctx client's channel context to associate with the channel
280 * @param peer peer identity the channel should go to
281 * @param port Port hash (port number).
282 * @param options CadetOption flag field, with all desired option bits set to 1.
284 * @return handle to the channel
286 struct GNUNET_CADET_Channel *
287 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
289 const struct GNUNET_PeerIdentity *peer,
290 const struct GNUNET_HashCode *port,
291 enum GNUNET_CADET_ChannelOption options);
295 * Destroy an existing channel.
297 * The existing end callback for the channel will be called immediately.
298 * Any pending outgoing messages will be sent but no incoming messages will be
299 * accepted and no data callbacks will be called.
301 * @param channel Channel handle, becomes invalid after this call.
304 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
308 * Struct to retrieve info about a channel.
310 union GNUNET_CADET_ChannelInfo
314 * #GNUNET_YES / #GNUNET_NO, for binary flags.
319 * Peer on the other side of the channel
321 const struct GNUNET_PeerIdentity peer;
326 * Get information about a channel.
328 * @param channel Channel handle.
329 * @param option Query type GNUNET_CADET_OPTION_*
330 * @param ... dependant on option, currently not used
331 * @return Union with an answer to the query.
333 const union GNUNET_CADET_ChannelInfo *
334 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
335 enum GNUNET_CADET_ChannelOption option,
340 * Handle for a transmission request.
342 struct GNUNET_CADET_TransmitHandle;
346 * Ask the cadet to call @a notify once it is ready to transmit the
347 * given number of bytes to the specified channel.
348 * Only one call can be active at any time, to issue another request,
349 * wait for the callback or cancel the current request.
351 * @param channel channel to use for transmission
352 * @param cork is corking allowed for this transmission?
353 * @param maxdelay how long can the message wait?
354 * @param notify_size how many bytes of buffer space does notify want?
355 * @param notify function to call when buffer space is available;
356 * will be called with NULL on timeout or if the overall queue
357 * for this peer is larger than queue_size and this is currently
358 * the message with the lowest priority
359 * @param notify_cls closure for @a notify
360 * @return non-NULL if the notify callback was queued,
361 * NULL if we can not even queue the request (insufficient
362 * memory); if NULL is returned, @a notify will NOT be called.
364 struct GNUNET_CADET_TransmitHandle *
365 GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
367 struct GNUNET_TIME_Relative maxdelay,
369 GNUNET_CONNECTION_TransmitReadyNotify notify,
374 * Cancel the specified transmission-ready notification.
377 * Since soon we will send immediately with mq (via request_data),
378 * there will be time or need to cancel a "pending" transmission.
380 * @param th handle that was returned by "notify_transmit_ready".
383 GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);
387 * Indicate readiness to receive the next message on a channel.
389 * Should only be called once per handler called.
391 * @param channel Channel that will be allowed to call another handler.
394 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
398 /******************************************************************************/
399 /******************** MONITORING /DEBUG API *************************/
400 /******************************************************************************/
401 /* The following calls are not useful for normal CADET operation, but for */
402 /* debug and monitoring of the cadet state. They can be safely ignored. */
403 /* The API can change at any point without notice. */
404 /* Please contact the developer if you consider any of this calls useful for */
405 /* normal cadet applications. */
406 /******************************************************************************/
410 * Method called to retrieve information about a specific channel the cadet peer
411 * is aware of, including all transit nodes.
413 * @param cls Closure.
414 * @param root Root of the channel.
415 * @param dest Destination of the channel.
416 * @param port Destination port of the channel.
417 * @param root_channel_number Local number for root, if known.
418 * @param dest_channel_number Local number for dest, if known.
419 * @param public_channel_numbe Number for P2P, always known.
422 (*GNUNET_CADET_ChannelCB) (void *cls,
423 const struct GNUNET_PeerIdentity *root,
424 const struct GNUNET_PeerIdentity *dest,
426 uint32_t root_channel_number,
427 uint32_t dest_channel_number,
428 uint32_t public_channel_number);
431 * Method called to retrieve information about all peers in CADET, called
434 * After last peer has been reported, an additional call with NULL is done.
436 * @param cls Closure.
437 * @param peer Peer, or NULL on "EOF".
438 * @param tunnel Do we have a tunnel towards this peer?
439 * @param n_paths Number of known paths towards this peer.
440 * @param best_path How long is the best path?
441 * (0 = unknown, 1 = ourselves, 2 = neighbor)
444 (*GNUNET_CADET_PeersCB) (void *cls,
445 const struct GNUNET_PeerIdentity *peer,
447 unsigned int n_paths,
448 unsigned int best_path);
451 * Method called to retrieve information about a specific peer
452 * known to the service.
454 * @param cls Closure.
455 * @param peer Peer ID.
456 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
457 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
458 * @param n_paths Number of paths known towards peer.
459 * @param paths Array of PEER_IDs representing all paths to reach the peer.
460 * Each path starts with the first hop (local peer not included).
461 * Each path ends with the destination peer (given in @c peer).
464 (*GNUNET_CADET_PeerCB) (void *cls,
465 const struct GNUNET_PeerIdentity *peer,
468 unsigned int n_paths,
469 struct GNUNET_PeerIdentity *paths);
473 * Method called to retrieve information about all tunnels in CADET, called
476 * After last tunnel has been reported, an additional call with NULL is done.
478 * @param cls Closure.
479 * @param peer Destination peer, or NULL on "EOF".
480 * @param channels Number of channels.
481 * @param connections Number of connections.
482 * @param estate Encryption state.
483 * @param cstate Connectivity state.
486 (*GNUNET_CADET_TunnelsCB) (void *cls,
487 const struct GNUNET_PeerIdentity *peer,
488 unsigned int channels,
489 unsigned int connections,
495 * Hash uniquely identifying a connection below a tunnel.
497 struct GNUNET_CADET_ConnectionTunnelIdentifier
499 struct GNUNET_CADET_Hash connection_of_tunnel;
504 * Number identifying a CADET channel.
506 struct GNUNET_CADET_ChannelNumber
508 uint32_t cn GNUNET_PACKED;
513 * Method called to retrieve information about a specific tunnel the cadet peer
514 * has established, o`r is trying to establish.
516 * @param cls Closure.
517 * @param peer Peer towards whom the tunnel is directed.
518 * @param n_channels Number of channels.
519 * @param n_connections Number of connections.
520 * @param channels Channels.
521 * @param connections Connections.
522 * @param estate Encryption state.
523 * @param cstate Connectivity state.
526 (*GNUNET_CADET_TunnelCB) (void *cls,
527 const struct GNUNET_PeerIdentity *peer,
528 unsigned int n_channels,
529 unsigned int n_connections,
530 const struct GNUNET_CADET_ChannelNumber *channels,
531 const struct GNUNET_CADET_ConnectionTunnelIdentifier *connections,
533 unsigned int cstate);
537 * Request information about a specific channel of the running cadet peer.
539 * WARNING: unstable API, likely to change in the future!
541 * @param h Handle to the cadet peer.
542 * @param peer ID of the other end of the channel.
543 * @param channel_number Channel number.
544 * @param callback Function to call with the requested data.
545 * @param callback_cls Closure for @c callback.
548 GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
549 struct GNUNET_PeerIdentity *peer,
550 uint32_t channel_number,
551 GNUNET_CADET_ChannelCB callback,
556 * Request a debug dump on the service's STDERR.
558 * WARNING: unstable API, likely to change in the future!
560 * @param h cadet handle
563 GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);
567 * Request information about peers known to the running cadet service.
568 * The callback will be called for every peer known to the service.
569 * Only one info request (of any kind) can be active at once.
572 * WARNING: unstable API, likely to change in the future!
574 * @param h Handle to the cadet peer.
575 * @param callback Function to call with the requested data.
576 * @param callback_cls Closure for @c callback.
578 * @return #GNUNET_OK / #GNUNET_SYSERR
581 GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
582 GNUNET_CADET_PeersCB callback,
587 * Cancel a peer info request. The callback will not be called (anymore).
589 * WARNING: unstable API, likely to change in the future!
591 * @param h Cadet handle.
593 * @return Closure that was given to #GNUNET_CADET_get_peers().
596 GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);
600 * Request information about a peer known to the running cadet peer.
601 * The callback will be called for the tunnel once.
602 * Only one info request (of any kind) can be active at once.
604 * WARNING: unstable API, likely to change in the future!
606 * @param h Handle to the cadet peer.
607 * @param id Peer whose tunnel to examine.
608 * @param callback Function to call with the requested data.
609 * @param callback_cls Closure for @c callback.
611 * @return #GNUNET_OK / #GNUNET_SYSERR
614 GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
615 const struct GNUNET_PeerIdentity *id,
616 GNUNET_CADET_PeerCB callback,
621 * Request information about tunnels of the running cadet peer.
622 * The callback will be called for every tunnel of the service.
623 * Only one info request (of any kind) can be active at once.
625 * WARNING: unstable API, likely to change in the future!
627 * @param h Handle to the cadet peer.
628 * @param callback Function to call with the requested data.
629 * @param callback_cls Closure for @c callback.
631 * @return #GNUNET_OK / #GNUNET_SYSERR
634 GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
635 GNUNET_CADET_TunnelsCB callback,
640 * Cancel a monitor request. The monitor callback will not be called.
642 * @param h Cadet handle.
644 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
647 GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);
651 * Request information about a tunnel of the running cadet peer.
652 * The callback will be called for the tunnel once.
653 * Only one info request (of any kind) can be active at once.
655 * WARNING: unstable API, likely to change in the future!
657 * @param h Handle to the cadet peer.
658 * @param id Peer whose tunnel to examine.
659 * @param callback Function to call with the requested data.
660 * @param callback_cls Closure for @c callback.
662 * @return #GNUNET_OK / #GNUNET_SYSERR
665 GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
666 const struct GNUNET_PeerIdentity *id,
667 GNUNET_CADET_TunnelCB callback,
672 * Create a message queue for a cadet channel.
673 * The message queue can only be used to transmit messages,
674 * not to receive them.
676 * @param channel the channel to create the message qeue for
677 * @return a message queue to messages over the channel
679 struct GNUNET_MQ_Handle *
680 GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);
684 * Transitional function to convert an unsigned int port to a hash value.
685 * WARNING: local static value returned, NOT reentrant!
686 * WARNING: do not use this function for new code!
688 * @param port Numerical port (unsigned int format).
690 * @return A GNUNET_HashCode usable for the new CADET API.
692 const struct GNUNET_HashCode *
693 GC_u2h (uint32_t port);
696 #if 0 /* keep Emacsens' auto-indent happy */
703 /* ifndef GNUNET_CADET_SERVICE_H */
706 /** @} */ /* end of group */
708 /* end of gnunet_cadet_service.h */