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3 Copyright (C) 2009-2014 GNUnet e.V.
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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
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;
72 * Channel options. Second line indicates filed in the
73 * CadetChannelInfo union carrying the answer.
75 enum GNUNET_CADET_ChannelOption
78 * Default options: unreliable, default buffering, not out of order.
80 GNUNET_CADET_OPTION_DEFAULT = 0x0,
83 * Disable buffering on intermediate nodes (for minimum latency).
86 GNUNET_CADET_OPTION_NOBUFFER = 0x1,
89 * Enable channel reliability, lost messages will be retransmitted.
92 GNUNET_CADET_OPTION_RELIABLE = 0x2,
95 * Enable out of order delivery of messages.
96 * Set bit for out-of-order delivery.
98 GNUNET_CADET_OPTION_OUT_OF_ORDER = 0x4,
101 * Who is the peer at the other end of the channel.
102 * Only for use in @c GNUNET_CADET_channel_get_info
103 * struct GNUNET_PeerIdentity *peer
105 GNUNET_CADET_OPTION_PEER = 0x8
111 * Functions with this signature are called whenever a message is
114 * Each time the function must call #GNUNET_CADET_receive_done on the channel
115 * in order to receive the next message. This doesn't need to be immediate:
116 * can be delayed if some processing is done on the message.
118 * @param cls Closure (set from #GNUNET_CADET_connect).
119 * @param channel Connection to the other end.
120 * @param channel_ctx Place to store local state associated with the channel.
121 * @param message The actual message.
122 * @return #GNUNET_OK to keep the channel open,
123 * #GNUNET_SYSERR to close it (signal serious error).
126 (*GNUNET_CADET_MessageCallback) (void *cls,
127 struct GNUNET_CADET_Channel *channel,
129 const struct GNUNET_MessageHeader *message);
133 * Message handler. Each struct specifies how to handle on particular
134 * type of message received.
136 struct GNUNET_CADET_MessageHandler
139 * Function to call for messages of type @e type.
141 GNUNET_CADET_MessageCallback callback;
144 * Type of the message this handler covers.
149 * Expected size of messages of this type. Use 0 for variable-size.
150 * If non-zero, messages of the given type will be discarded if they
151 * do not have the right size.
153 uint16_t expected_size;
158 * Method called whenever another peer has added us to a channel
159 * the other peer initiated.
160 * Only called (once) upon reception of data with a message type which was
161 * subscribed to in #GNUNET_CADET_connect.
163 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
164 * this case the handler MUST return NULL.
167 * @param channel new handle to the channel
168 * @param initiator peer that started the channel
169 * @param port Port this channel is for.
170 * @param options CadetOption flag field, with all active option bits set to 1.
172 * @return initial channel context for the channel
173 * (can be NULL -- that's not an error)
176 (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
177 struct GNUNET_CADET_Channel *channel,
178 const struct GNUNET_PeerIdentity *initiator,
179 const struct GNUNET_HashCode *port,
180 enum GNUNET_CADET_ChannelOption options);
184 * Function called whenever a channel is destroyed. Should clean up
185 * any associated state, including cancelling any pending transmission on this
188 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
190 * @param cls closure (set from #GNUNET_CADET_connect)
191 * @param channel connection to the other end (henceforth invalid)
192 * @param channel_ctx place where local state associated
193 * with the channel is stored
196 (GNUNET_CADET_ChannelEndHandler) (void *cls,
197 const struct GNUNET_CADET_Channel *channel,
202 * Connect to the cadet service.
204 * @param cfg Configuration to use.
205 * @param cls Closure for the various callbacks that follow (including
206 * handlers in the handlers array).
207 * @param cleaner Function called when a channel is destroyed.
208 * It is called immediately if #GNUNET_CADET_channel_destroy
209 * is called on the channel.
210 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
211 * one must call #GNUNET_CADET_receive_done on the channel to
212 * receive the next message. Messages of a type that is not
213 * in the handlers array are ignored if received.
215 * @return handle to the cadet service NULL on error
216 * (in this case, init is never called)
218 struct GNUNET_CADET_Handle *
219 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
221 GNUNET_CADET_ChannelEndHandler cleaner,
222 const struct GNUNET_CADET_MessageHandler *handlers);
226 * Disconnect from the cadet service. All channels will be destroyed. All channel
227 * disconnect callbacks will be called on any still connected peers, notifying
228 * about their disconnection. The registered inbound channel cleaner will be
229 * called should any inbound channels still exist.
231 * @param handle connection to cadet to disconnect
234 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
237 * Open a port to receive incomming channels.
239 * @param h CADET handle.
240 * @param port Hash representing the port number.
241 * @param new_channel Function called when an channel is received.
242 * @param new_channel_cls Closure for @a new_channel.
244 * @return Port handle.
246 struct GNUNET_CADET_Port *
247 GNUNET_CADET_open_port (struct GNUNET_CADET_Handle *h,
248 const struct GNUNET_HashCode *port,
249 GNUNET_CADET_InboundChannelNotificationHandler new_channel,
250 void *new_channel_cls);
253 * Close a port opened with @a GNUNET_CADET_open_port.
254 * The @a new_channel callback will no longer be called.
256 * @param p Port handle.
259 GNUNET_CADET_close_port (struct GNUNET_CADET_Port *p);
262 * Create a new channel towards a remote peer.
264 * If the destination port is not open by any peer or the destination peer
265 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
268 * @param h cadet handle
269 * @param channel_ctx client's channel context to associate with the channel
270 * @param peer peer identity the channel should go to
271 * @param port Port hash (port number).
272 * @param options CadetOption flag field, with all desired option bits set to 1.
274 * @return handle to the channel
276 struct GNUNET_CADET_Channel *
277 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
279 const struct GNUNET_PeerIdentity *peer,
280 const struct GNUNET_HashCode *port,
281 enum GNUNET_CADET_ChannelOption options);
285 * Destroy an existing channel.
287 * The existing end callback for the channel will be called immediately.
288 * Any pending outgoing messages will be sent but no incoming messages will be
289 * accepted and no data callbacks will be called.
291 * @param channel Channel handle, becomes invalid after this call.
294 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
298 * Struct to retrieve info about a channel.
300 union GNUNET_CADET_ChannelInfo
304 * #GNUNET_YES / #GNUNET_NO, for binary flags.
309 * Peer on the other side of the channel
311 const struct GNUNET_PeerIdentity peer;
316 * Get information about a channel.
318 * @param channel Channel handle.
319 * @param option Query type GNUNET_CADET_OPTION_*
320 * @param ... dependant on option, currently not used
321 * @return Union with an answer to the query.
323 const union GNUNET_CADET_ChannelInfo *
324 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
325 enum GNUNET_CADET_ChannelOption option,
330 * Handle for a transmission request.
332 struct GNUNET_CADET_TransmitHandle;
336 * Ask the cadet to call @a notify once it is ready to transmit the
337 * given number of bytes to the specified channel.
338 * Only one call can be active at any time, to issue another request,
339 * wait for the callback or cancel the current request.
341 * @param channel channel to use for transmission
342 * @param cork is corking allowed for this transmission?
343 * @param maxdelay how long can the message wait?
344 * @param notify_size how many bytes of buffer space does notify want?
345 * @param notify function to call when buffer space is available;
346 * will be called with NULL on timeout or if the overall queue
347 * for this peer is larger than queue_size and this is currently
348 * the message with the lowest priority
349 * @param notify_cls closure for @a notify
350 * @return non-NULL if the notify callback was queued,
351 * NULL if we can not even queue the request (insufficient
352 * memory); if NULL is returned, @a notify will NOT be called.
354 struct GNUNET_CADET_TransmitHandle *
355 GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
357 struct GNUNET_TIME_Relative maxdelay,
359 GNUNET_CONNECTION_TransmitReadyNotify notify,
364 * Cancel the specified transmission-ready notification.
367 * Since soon we will send immediately with mq (via request_data),
368 * there will be time or need to cancel a "pending" transmission.
370 * @param th handle that was returned by "notify_transmit_ready".
373 GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);
377 * Indicate readiness to receive the next message on a channel.
379 * Should only be called once per handler called.
381 * @param channel Channel that will be allowed to call another handler.
384 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
388 /******************************************************************************/
389 /******************** MONITORING /DEBUG API *************************/
390 /******************************************************************************/
391 /* The following calls are not useful for normal CADET operation, but for */
392 /* debug and monitoring of the cadet state. They can be safely ignored. */
393 /* The API can change at any point without notice. */
394 /* Please contact the developer if you consider any of this calls useful for */
395 /* normal cadet applications. */
396 /******************************************************************************/
400 * Method called to retrieve information about a specific channel the cadet peer
401 * is aware of, including all transit nodes.
403 * @param cls Closure.
404 * @param root Root of the channel.
405 * @param dest Destination of the channel.
406 * @param port Destination port of the channel.
407 * @param root_channel_number Local number for root, if known.
408 * @param dest_channel_number Local number for dest, if known.
409 * @param public_channel_numbe Number for P2P, always known.
412 (*GNUNET_CADET_ChannelCB) (void *cls,
413 const struct GNUNET_PeerIdentity *root,
414 const struct GNUNET_PeerIdentity *dest,
415 uint32_t /* UGH */ port,
416 uint32_t /* ugh */ root_channel_number,
417 uint32_t /* ugh */ dest_channel_number,
418 uint32_t /* ugh */ public_channel_number);
421 * Method called to retrieve information about all peers in CADET, called
424 * After last peer has been reported, an additional call with NULL is done.
426 * @param cls Closure.
427 * @param peer Peer, or NULL on "EOF".
428 * @param tunnel Do we have a tunnel towards this peer?
429 * @param n_paths Number of known paths towards this peer.
430 * @param best_path How long is the best path?
431 * (0 = unknown, 1 = ourselves, 2 = neighbor)
434 (*GNUNET_CADET_PeersCB) (void *cls,
435 const struct GNUNET_PeerIdentity *peer,
437 unsigned int n_paths,
438 unsigned int best_path);
441 * Method called to retrieve information about a specific peer
442 * known to the service.
444 * @param cls Closure.
445 * @param peer Peer ID.
446 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
447 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
448 * @param n_paths Number of paths known towards peer.
449 * @param paths Array of PEER_IDs representing all paths to reach the peer.
450 * Each path starts with the first hop (local peer not included).
451 * Each path ends with the destination peer (given in @c peer).
454 (*GNUNET_CADET_PeerCB) (void *cls,
455 const struct GNUNET_PeerIdentity *peer,
458 unsigned int n_paths,
459 const struct GNUNET_PeerIdentity *paths);
463 * Method called to retrieve information about all tunnels in CADET, called
466 * After last tunnel has been reported, an additional call with NULL is done.
468 * @param cls Closure.
469 * @param peer Destination peer, or NULL on "EOF".
470 * @param channels Number of channels.
471 * @param connections Number of connections.
472 * @param estate Encryption state.
473 * @param cstate Connectivity state.
476 (*GNUNET_CADET_TunnelsCB) (void *cls,
477 const struct GNUNET_PeerIdentity *peer,
478 unsigned int channels,
479 unsigned int connections,
485 * Hash uniquely identifying a connection below a tunnel.
487 struct GNUNET_CADET_ConnectionTunnelIdentifier
489 struct GNUNET_ShortHashCode connection_of_tunnel;
494 * Number identifying a CADET channel within a tunnel.
496 struct GNUNET_CADET_ChannelTunnelNumber
499 * Which number does this channel have that uniquely identfies
500 * it within its tunnel, in network byte order.
502 * Given two peers, both may initiate channels over the same tunnel.
503 * The @e cn must be greater or equal to 0x80000000 (high-bit set)
504 * for tunnels initiated with the peer that has the larger peer
505 * identity as compared using #GNUNET_CRYPTO_cmp_peer_identity().
507 uint32_t cn GNUNET_PACKED;
512 * Method called to retrieve information about a specific tunnel the cadet peer
513 * has established, o`r is trying to establish.
515 * @param cls Closure.
516 * @param peer Peer towards whom the tunnel is directed.
517 * @param n_channels Number of channels.
518 * @param n_connections Number of connections.
519 * @param channels Channels.
520 * @param connections Connections.
521 * @param estate Encryption state.
522 * @param cstate Connectivity state.
525 (*GNUNET_CADET_TunnelCB) (void *cls,
526 const struct GNUNET_PeerIdentity *peer,
527 unsigned int n_channels,
528 unsigned int n_connections,
529 const struct GNUNET_CADET_ChannelTunnelNumber *channels,
530 const struct GNUNET_CADET_ConnectionTunnelIdentifier *connections,
532 unsigned int cstate);
536 * Request information about a specific channel of the running cadet peer.
538 * WARNING: unstable API, likely to change in the future!
540 * @param h Handle to the cadet peer.
541 * @param peer ID of the other end of the channel.
542 * @param channel_number Channel number.
543 * @param callback Function to call with the requested data.
544 * @param callback_cls Closure for @c callback.
547 GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
548 struct GNUNET_PeerIdentity *peer,
549 uint32_t /* UGH */ channel_number,
550 GNUNET_CADET_ChannelCB callback,
555 * Request a debug dump on the service's STDERR.
557 * WARNING: unstable API, likely to change in the future!
559 * @param h cadet handle
562 GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);
566 * Request information about peers known to the running cadet service.
567 * The callback will be called for every peer known to the service.
568 * Only one info request (of any kind) can be active at once.
571 * WARNING: unstable API, likely to change in the future!
573 * @param h Handle to the cadet peer.
574 * @param callback Function to call with the requested data.
575 * @param callback_cls Closure for @c callback.
577 * @return #GNUNET_OK / #GNUNET_SYSERR
580 GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
581 GNUNET_CADET_PeersCB callback,
586 * Cancel a peer info request. The callback will not be called (anymore).
588 * WARNING: unstable API, likely to change in the future!
590 * @param h Cadet handle.
592 * @return Closure that was given to #GNUNET_CADET_get_peers().
595 GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);
599 * Request information about a peer known to the running cadet peer.
600 * The callback will be called for the tunnel once.
601 * Only one info request (of any kind) can be active at once.
603 * WARNING: unstable API, likely to change in the future!
605 * @param h Handle to the cadet peer.
606 * @param id Peer whose tunnel to examine.
607 * @param callback Function to call with the requested data.
608 * @param callback_cls Closure for @c callback.
610 * @return #GNUNET_OK / #GNUNET_SYSERR
613 GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
614 const struct GNUNET_PeerIdentity *id,
615 GNUNET_CADET_PeerCB callback,
620 * Request information about tunnels of the running cadet peer.
621 * The callback will be called for every tunnel of the service.
622 * Only one info request (of any kind) can be active at once.
624 * WARNING: unstable API, likely to change in the future!
626 * @param h Handle to the cadet peer.
627 * @param callback Function to call with the requested data.
628 * @param callback_cls Closure for @c callback.
630 * @return #GNUNET_OK / #GNUNET_SYSERR
633 GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
634 GNUNET_CADET_TunnelsCB callback,
639 * Cancel a monitor request. The monitor callback will not be called.
641 * @param h Cadet handle.
643 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
646 GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);
650 * Request information about a tunnel of the running cadet peer.
651 * The callback will be called for the tunnel once.
652 * Only one info request (of any kind) can be active at once.
654 * WARNING: unstable API, likely to change in the future!
656 * @param h Handle to the cadet peer.
657 * @param id Peer whose tunnel to examine.
658 * @param callback Function to call with the requested data.
659 * @param callback_cls Closure for @c callback.
661 * @return #GNUNET_OK / #GNUNET_SYSERR
664 GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
665 const struct GNUNET_PeerIdentity *id,
666 GNUNET_CADET_TunnelCB callback,
671 * Create a message queue for a cadet channel.
672 * The message queue can only be used to transmit messages,
673 * not to receive them.
675 * @param channel the channel to create the message qeue for
676 * @return a message queue to messages over the channel
678 struct GNUNET_MQ_Handle *
679 GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);
683 * Transitional function to convert an unsigned int port to a hash value.
684 * WARNING: local static value returned, NOT reentrant!
685 * WARNING: do not use this function for new code!
687 * @param port Numerical port (unsigned int format).
689 * @return A GNUNET_HashCode usable for the new CADET API.
691 const struct GNUNET_HashCode *
692 GC_u2h (uint32_t port);
695 /******************************************************************************/
696 /******************************* MQ-BASED API *********************************/
697 /******************************************************************************/
700 * Method called whenever a peer connects to a port in MQ-based CADET.
702 * @param cls Closure from #GNUNET_CADET_open_porT.
703 * @param channel New handle to the channel.
704 * @param source Peer that started this channel.
705 * @return Closure for the incoming @a channel. It's given to:
706 * - The #GNUNET_CADET_DisconnectEventHandler (given to
707 * #GNUNET_CADET_open_porT) when the channel dies.
708 * - Each the #GNUNET_MQ_MessageCallback handlers for each message
709 * received on the @a channel.
712 (*GNUNET_CADET_ConnectEventHandler) (void *cls,
713 struct GNUNET_CADET_Channel *channel,
714 const struct GNUNET_PeerIdentity *source);
718 * Function called whenever an MQ-channel is destroyed, even if the destruction
719 * was requested by #GNUNET_CADET_channel_destroy.
720 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
722 * It should clean up any associated state, including cancelling any pending
723 * transmission on this channel.
725 * @param cls Channel closure.
726 * @param channel Connection to the other end (henceforth invalid).
729 (*GNUNET_CADET_DisconnectEventHandler) (void *cls,
730 const struct GNUNET_CADET_Channel *channel);
734 * Function called whenever an MQ-channel's transmission window size changes.
736 * The first callback in an outgoing channel will be with a non-zero value
737 * and will mean the channel is connected to the destination.
739 * For an incoming channel it will be called immediately after the
740 * #GNUNET_CADET_ConnectEventHandler, also with a non-zero value.
742 * @param cls Channel closure.
743 * @param channel Connection to the other end --- FIXME: drop?
744 * @param window_size New window size. If the is more messages than buffer size
745 * this value will be negative. -- FIXME: make unsigned, we never call negative?
748 (*GNUNET_CADET_WindowSizeEventHandler) (void *cls,
749 const struct GNUNET_CADET_Channel *channel,
754 * Connect to the MQ-based cadet service.
756 * @param cfg Configuration to use.
757 * @return Handle to the cadet service NULL on error.
759 struct GNUNET_CADET_Handle *
760 GNUNET_CADET_connecT (const struct GNUNET_CONFIGURATION_Handle *cfg);
764 * Open a port to receive incomming MQ-based channels.
766 * @param h CADET handle.
767 * @param port Hash identifying the port.
768 * @param connects Function called when an incoming channel is connected.
769 * @param connects_cls Closure for the @a connects handler.
770 * @param window_changes Function called when the transmit window size changes.
772 * @param disconnects Function called when a channel is disconnected.
773 * @param handlers Callbacks for messages we care about, NULL-terminated.
774 * @return Port handle.
776 struct GNUNET_CADET_Port *
777 GNUNET_CADET_open_porT (struct GNUNET_CADET_Handle *h,
778 const struct GNUNET_HashCode *port,
779 GNUNET_CADET_ConnectEventHandler connects,
781 GNUNET_CADET_WindowSizeEventHandler window_changes,
782 GNUNET_CADET_DisconnectEventHandler disconnects,
783 const struct GNUNET_MQ_MessageHandler *handlers);
786 * Create a new channel towards a remote peer.
788 * If the destination port is not open by any peer or the destination peer
789 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
792 * @param h CADET handle.
793 * @param channel_cls Closure for the channel. It's given to:
794 * - The management handler @a window_changes.
795 * - The disconnect handler @a disconnects
796 * - Each message type callback in @a handlers
797 * @param destination Peer identity the channel should go to.
798 * @param port Identification of the destination port.
799 * @param options CadetOption flag field, with all desired option bits set to 1.
800 * @param window_changes Function called when the transmit window size changes.
801 * Can be NULL if this data is of no interest.
802 * TODO Not yet implemented.
803 * @param disconnects Function called when the channel is disconnected.
804 * @param handlers Callbacks for messages we care about, NULL-terminated.
805 * @return Handle to the channel.
807 struct GNUNET_CADET_Channel *
808 GNUNET_CADET_channel_creatE (struct GNUNET_CADET_Handle *h,
810 const struct GNUNET_PeerIdentity *destination,
811 const struct GNUNET_HashCode *port,
812 enum GNUNET_CADET_ChannelOption options,
813 GNUNET_CADET_WindowSizeEventHandler window_changes,
814 GNUNET_CADET_DisconnectEventHandler disconnects,
815 const struct GNUNET_MQ_MessageHandler *handlers);
819 * Obtain the message queue for a connected channel.
821 * @param channel The channel handle from which to get the MQ.
822 * @return The message queue of the channel.
824 struct GNUNET_MQ_Handle *
825 GNUNET_CADET_get_mq (const struct GNUNET_CADET_Channel *channel);
828 /******************************************************************************/
829 /******************************* MQ-BASED API *********************************/
830 /******************************************************************************/
834 #if 0 /* keep Emacsens' auto-indent happy */
841 /* ifndef GNUNET_CADET_SERVICE_H */
844 /** @} */ /* end of group */
846 /* end of gnunet_cadet_service.h */