2 This file is part of GNUnet.
3 (C) 2009-2014 Christian Grothoff (and other contributing authors)
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21 * @file include/gnunet_cadet_service.h
22 * @brief cadet service; establish channels to distant peers
23 * @author Christian Grothoff
26 #ifndef GNUNET_CADET_SERVICE_H
27 #define GNUNET_CADET_SERVICE_H
32 #if 0 /* keep Emacsens' auto-indent happy */
37 #include "gnunet_util_lib.h"
38 #include "gnunet_transport_service.h"
41 * Version number of GNUnet-cadet API.
43 #define GNUNET_CADET_VERSION 0x00000003
47 * Opaque handle to the service.
49 struct GNUNET_CADET_Handle;
52 * Opaque handle to a channel.
54 struct GNUNET_CADET_Channel;
57 * Hash to be used in Cadet communication. Only 256 bits needed,
58 * instead of the 512 from `struct GNUNET_HashCode`.
60 struct GNUNET_CADET_Hash
62 unsigned char bits[256 / 8];
67 * Channel options. Second line indicates filed in the
68 * CadetChannelInfo union carrying the answer.
70 enum GNUNET_CADET_ChannelOption
73 * Default options: unreliable, default buffering, not out of order.
75 GNUNET_CADET_OPTION_DEFAULT = 0x0,
78 * Disable buffering on intermediate nodes (for minimum latency).
81 GNUNET_CADET_OPTION_NOBUFFER = 0x1,
84 * Enable channel reliability, lost messages will be retransmitted.
87 GNUNET_CADET_OPTION_RELIABLE = 0x2,
90 * Enable out of order delivery of messages.
93 GNUNET_CADET_OPTION_OOORDER = 0x4,
96 * Who is the peer at the other end of the channel.
97 * Only for use in @c GNUNET_CADET_channel_get_info
98 * struct GNUNET_PeerIdentity *peer
100 GNUNET_CADET_OPTION_PEER = 0x8
106 * Functions with this signature are called whenever a message is
109 * Each time the function must call #GNUNET_CADET_receive_done on the channel
110 * in order to receive the next message. This doesn't need to be immediate:
111 * can be delayed if some processing is done on the message.
113 * @param cls Closure (set from #GNUNET_CADET_connect).
114 * @param channel Connection to the other end.
115 * @param channel_ctx Place to store local state associated with the channel.
116 * @param message The actual message.
117 * @return #GNUNET_OK to keep the channel open,
118 * #GNUNET_SYSERR to close it (signal serious error).
121 (*GNUNET_CADET_MessageCallback) (void *cls,
122 struct GNUNET_CADET_Channel *channel,
124 const struct GNUNET_MessageHeader *message);
128 * Message handler. Each struct specifies how to handle on particular
129 * type of message received.
131 struct GNUNET_CADET_MessageHandler
134 * Function to call for messages of type @e type.
136 GNUNET_CADET_MessageCallback callback;
139 * Type of the message this handler covers.
144 * Expected size of messages of this type. Use 0 for variable-size.
145 * If non-zero, messages of the given type will be discarded if they
146 * do not have the right size.
148 uint16_t expected_size;
153 * Method called whenever another peer has added us to a channel
154 * the other peer initiated.
155 * Only called (once) upon reception of data with a message type which was
156 * subscribed to in #GNUNET_CADET_connect.
158 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
159 * this case the handler MUST return NULL.
162 * @param channel new handle to the channel
163 * @param initiator peer that started the channel
164 * @param port Port this channel is for.
165 * @param options CadetOption flag field, with all active option bits set to 1.
167 * @return initial channel context for the channel
168 * (can be NULL -- that's not an error)
171 (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
172 struct GNUNET_CADET_Channel *channel,
173 const struct GNUNET_PeerIdentity *initiator,
175 enum GNUNET_CADET_ChannelOption options);
179 * Function called whenever a channel is destroyed. Should clean up
180 * any associated state.
182 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
184 * @param cls closure (set from #GNUNET_CADET_connect)
185 * @param channel connection to the other end (henceforth invalid)
186 * @param channel_ctx place where local state associated
187 * with the channel is stored
190 (GNUNET_CADET_ChannelEndHandler) (void *cls,
191 const struct GNUNET_CADET_Channel *channel,
196 * Connect to the cadet service.
198 * @param cfg Configuration to use.
199 * @param cls Closure for the various callbacks that follow (including
200 * handlers in the handlers array).
201 * @param new_channel Function called when an *incoming* channel is created.
202 * Can be NULL if no inbound channels are desired.
204 * @param cleaner Function called when a channel is destroyed by the remote peer.
205 * It is NOT called if #GNUNET_CADET_channel_destroy is called on
207 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
208 * one must call #GNUNET_CADET_receive_done on the channel to
209 * receive the next message. Messages of a type that is not
210 * in the handlers array are ignored if received.
211 * @param ports NULL or 0-terminated array of port numbers for incoming channels.
212 * See @a new_channel.
214 * @return handle to the cadet service NULL on error
215 * (in this case, init is never called)
217 struct GNUNET_CADET_Handle *
218 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
220 GNUNET_CADET_InboundChannelNotificationHandler new_channel,
221 GNUNET_CADET_ChannelEndHandler cleaner,
222 const struct GNUNET_CADET_MessageHandler *handlers,
223 const uint32_t *ports);
227 * Disconnect from the cadet service. All channels will be destroyed. All channel
228 * disconnect callbacks will be called on any still connected peers, notifying
229 * about their disconnection. The registered inbound channel cleaner will be
230 * called should any inbound channels still exist.
232 * @param handle connection to cadet to disconnect
235 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
239 * Create a new channel towards a remote peer.
241 * If the destination port is not open by any peer or the destination peer
242 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
245 * @param h cadet handle
246 * @param channel_ctx client's channel context to associate with the channel
247 * @param peer peer identity the channel should go to
248 * @param port Port number.
249 * @param options CadetOption flag field, with all desired option bits set to 1.
251 * @return handle to the channel
253 struct GNUNET_CADET_Channel *
254 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
256 const struct GNUNET_PeerIdentity *peer,
258 enum GNUNET_CADET_ChannelOption options);
262 * Destroy an existing channel.
264 * The existing end callback for the channel will be called immediately.
265 * Any pending outgoing messages will be sent but no incoming messages will be
266 * accepted and no data callbacks will be called.
268 * @param channel Channel handle, becomes invalid after this call.
271 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
275 * Struct to retrieve info about a channel.
277 union GNUNET_CADET_ChannelInfo
281 * #GNUNET_YES / #GNUNET_NO, for binary flags.
286 * Peer on the other side of the channel
288 const struct GNUNET_PeerIdentity peer;
293 * Get information about a channel.
295 * @param channel Channel handle.
296 * @param option Query type GNUNET_CADET_OPTION_*
297 * @param ... dependant on option, currently not used
298 * @return Union with an answer to the query.
300 const union GNUNET_CADET_ChannelInfo *
301 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
302 enum GNUNET_CADET_ChannelOption option, ...);
306 * Handle for a transmission request.
308 struct GNUNET_CADET_TransmitHandle;
312 * Ask the cadet to call @a notify once it is ready to transmit the
313 * given number of bytes to the specified channel.
314 * Only one call can be active at any time, to issue another request,
315 * wait for the callback or cancel the current request.
317 * @param channel channel to use for transmission
318 * @param cork is corking allowed for this transmission?
319 * @param maxdelay how long can the message wait?
320 * @param notify_size how many bytes of buffer space does notify want?
321 * @param notify function to call when buffer space is available;
322 * will be called with NULL on timeout or if the overall queue
323 * for this peer is larger than queue_size and this is currently
324 * the message with the lowest priority
325 * @param notify_cls closure for @a notify
326 * @return non-NULL if the notify callback was queued,
327 * NULL if we can not even queue the request (insufficient
328 * memory); if NULL is returned, @a notify will NOT be called.
330 struct GNUNET_CADET_TransmitHandle *
331 GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
333 struct GNUNET_TIME_Relative maxdelay,
335 GNUNET_CONNECTION_TransmitReadyNotify notify,
340 * Cancel the specified transmission-ready notification.
342 * @param th handle that was returned by "notify_transmit_ready".
345 GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);
349 * Indicate readiness to receive the next message on a channel.
351 * Should only be called once per handler called.
353 * @param channel Channel that will be allowed to call another handler.
356 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
360 /******************************************************************************/
361 /******************** MONITORING /DEBUG API *************************/
362 /******************************************************************************/
363 /* The following calls are not useful for normal CADET operation, but for */
364 /* debug and monitoring of the cadet state. They can be safely ignored. */
365 /* The API can change at any point without notice. */
366 /* Please contact the developer if you consider any of this calls useful for */
367 /* normal cadet applications. */
368 /******************************************************************************/
372 * Method called to retrieve information about a specific channel the cadet peer
373 * is aware of, including all transit nodes.
375 * @param cls Closure.
376 * @param root Root of the channel.
377 * @param dest Destination of the channel.
378 * @param port Destination port of the channel.
379 * @param root_channel_number Local number for root, if known.
380 * @param dest_channel_number Local number for dest, if known.
381 * @param public_channel_numbe Number for P2P, always known.
384 (*GNUNET_CADET_ChannelCB) (void *cls,
385 const struct GNUNET_PeerIdentity *root,
386 const struct GNUNET_PeerIdentity *dest,
388 uint32_t root_channel_number,
389 uint32_t dest_channel_number,
390 uint32_t public_channel_number);
393 * Method called to retrieve information about all peers in CADET, called
396 * After last peer has been reported, an additional call with NULL is done.
398 * @param cls Closure.
399 * @param peer Peer, or NULL on "EOF".
400 * @param tunnel Do we have a tunnel towards this peer?
401 * @param n_paths Number of known paths towards this peer.
402 * @param best_path How long is the best path?
403 * (0 = unknown, 1 = ourselves, 2 = neighbor)
406 (*GNUNET_CADET_PeersCB) (void *cls,
407 const struct GNUNET_PeerIdentity *peer,
409 unsigned int n_paths,
410 unsigned int best_path);
413 * Method called to retrieve information about a specific peer
414 * known to the service.
416 * @param cls Closure.
417 * @param peer Peer ID.
418 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
419 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
420 * @param n_paths Number of paths known towards peer.
421 * @param paths Array of PEER_IDs representing all paths to reach the peer.
422 * Each path starts with the local peer.
423 * Each path ends with the destination peer (given in @c peer).
426 (*GNUNET_CADET_PeerCB) (void *cls,
427 const struct GNUNET_PeerIdentity *peer,
430 unsigned int n_paths,
431 struct GNUNET_PeerIdentity *paths);
435 * Method called to retrieve information about all tunnels in CADET, called
438 * After last tunnel has been reported, an additional call with NULL is done.
440 * @param cls Closure.
441 * @param peer Destination peer, or NULL on "EOF".
442 * @param channels Number of channels.
443 * @param connections Number of connections.
444 * @param estate Encryption state.
445 * @param cstate Connectivity state.
448 (*GNUNET_CADET_TunnelsCB) (void *cls,
449 const struct GNUNET_PeerIdentity *peer,
450 unsigned int channels,
451 unsigned int connections,
457 * Method called to retrieve information about a specific tunnel the cadet peer
458 * has established, o`r is trying to establish.
460 * @param cls Closure.
461 * @param peer Peer towards whom the tunnel is directed.
462 * @param n_channels Number of channels.
463 * @param n_connections Number of connections.
464 * @param channels Channels.
465 * @param connections Connections.
466 * @param estate Encryption state.
467 * @param cstate Connectivity state.
470 (*GNUNET_CADET_TunnelCB) (void *cls,
471 const struct GNUNET_PeerIdentity *peer,
472 unsigned int n_channels,
473 unsigned int n_connections,
475 struct GNUNET_CADET_Hash *connections,
477 unsigned int cstate);
481 * Request information about a specific channel of the running cadet peer.
483 * WARNING: unstable API, likely to change in the future!
485 * @param h Handle to the cadet peer.
486 * @param peer ID of the other end of the channel.
487 * @param channel_number Channel number.
488 * @param callback Function to call with the requested data.
489 * @param callback_cls Closure for @c callback.
492 GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
493 struct GNUNET_PeerIdentity *peer,
494 uint32_t channel_number,
495 GNUNET_CADET_ChannelCB callback,
500 * Request a debug dump on the service's STDERR.
502 * WARNING: unstable API, likely to change in the future!
504 * @param h cadet handle
507 GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);
511 * Request information about peers known to the running cadet service.
512 * The callback will be called for every peer known to the service.
513 * Only one info request (of any kind) can be active at once.
516 * WARNING: unstable API, likely to change in the future!
518 * @param h Handle to the cadet peer.
519 * @param callback Function to call with the requested data.
520 * @param callback_cls Closure for @c callback.
522 * @return #GNUNET_OK / #GNUNET_SYSERR
525 GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
526 GNUNET_CADET_PeersCB callback,
531 * Cancel a peer info request. The callback will not be called (anymore).
533 * WARNING: unstable API, likely to change in the future!
535 * @param h Cadet handle.
537 * @return Closure that was given to #GNUNET_CADET_get_peers().
540 GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);
544 * Request information about a peer known to the running cadet peer.
545 * The callback will be called for the tunnel once.
546 * Only one info request (of any kind) can be active at once.
548 * WARNING: unstable API, likely to change in the future!
550 * @param h Handle to the cadet peer.
551 * @param id Peer whose tunnel to examine.
552 * @param callback Function to call with the requested data.
553 * @param callback_cls Closure for @c callback.
555 * @return #GNUNET_OK / #GNUNET_SYSERR
558 GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
559 const struct GNUNET_PeerIdentity *id,
560 GNUNET_CADET_PeerCB callback,
565 * Request information about tunnels of the running cadet peer.
566 * The callback will be called for every tunnel of the service.
567 * Only one info request (of any kind) can be active at once.
569 * WARNING: unstable API, likely to change in the future!
571 * @param h Handle to the cadet peer.
572 * @param callback Function to call with the requested data.
573 * @param callback_cls Closure for @c callback.
575 * @return #GNUNET_OK / #GNUNET_SYSERR
578 GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
579 GNUNET_CADET_TunnelsCB callback,
584 * Cancel a monitor request. The monitor callback will not be called.
586 * @param h Cadet handle.
588 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
591 GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);
595 * Request information about a tunnel of the running cadet peer.
596 * The callback will be called for the tunnel once.
597 * Only one info request (of any kind) can be active at once.
599 * WARNING: unstable API, likely to change in the future!
601 * @param h Handle to the cadet peer.
602 * @param id Peer whose tunnel to examine.
603 * @param callback Function to call with the requested data.
604 * @param callback_cls Closure for @c callback.
606 * @return #GNUNET_OK / #GNUNET_SYSERR
609 GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
610 const struct GNUNET_PeerIdentity *id,
611 GNUNET_CADET_TunnelCB callback,
616 * Create a message queue for a cadet channel.
617 * The message queue can only be used to transmit messages,
618 * not to receive them.
620 * @param channel the channel to create the message qeue for
621 * @return a message queue to messages over the channel
623 struct GNUNET_MQ_Handle *
624 GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);
627 #if 0 /* keep Emacsens' auto-indent happy */
634 /* ifndef GNUNET_CADET_SERVICE_H */
636 /* end of gnunet_cadet_service.h */