summaryrefslogtreecommitdiff
path: root/src/include/gnunet_cadet_service.h
blob: 7f370c6ab9501292d2454941681dcae57cf02b3d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
/*
     This file is part of GNUnet.
     (C) 2009-2014 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/
/**
 * @file include/gnunet_cadet_service.h
 * @brief cadet service; establish channels to distant peers
 * @author Christian Grothoff
 * @author Bart Polot
 */
#ifndef GNUNET_CADET_SERVICE_H
#define GNUNET_CADET_SERVICE_H

#ifdef __cplusplus
extern "C"
{
#if 0                           /* keep Emacsens' auto-indent happy */
}
#endif
#endif

#include "gnunet_util_lib.h"
#include "gnunet_transport_service.h"

/**
 * Version number of GNUnet-cadet API.
 */
#define GNUNET_CADET_VERSION 0x00000003


/**
 * Opaque handle to the service.
 */
struct GNUNET_CADET_Handle;

/**
 * Opaque handle to a channel.
 */
struct GNUNET_CADET_Channel;

/**
 * Hash to be used in Cadet communication. Only 256 bits needed,
 * instead of the 512 from `struct GNUNET_HashCode`.
 */
struct GNUNET_CADET_Hash
{
  unsigned char bits[256 / 8];
};


/**
 * Channel options.  Second line indicates filed in the
 * CadetChannelInfo union carrying the answer.
 */
enum GNUNET_CADET_ChannelOption
{
  /**
   * Default options: unreliable, default buffering, not out of order.
   */
  GNUNET_CADET_OPTION_DEFAULT    = 0x0,

  /**
   * Disable buffering on intermediate nodes (for minimum latency).
   * Yes/No.
   */
  GNUNET_CADET_OPTION_NOBUFFER   = 0x1,

  /**
   * Enable channel reliability, lost messages will be retransmitted.
   * Yes/No.
   */
  GNUNET_CADET_OPTION_RELIABLE   = 0x2,

  /**
   * Enable out of order delivery of messages.
   * Yes/No.
   */
  GNUNET_CADET_OPTION_OOORDER    = 0x4,

  /**
   * Who is the peer at the other end of the channel.
   * Only for use in @c GNUNET_CADET_channel_get_info
   * struct GNUNET_PeerIdentity *peer
   */
  GNUNET_CADET_OPTION_PEER       = 0x8

};


/**
 * Functions with this signature are called whenever a message is
 * received.
 *
 * Each time the function must call #GNUNET_CADET_receive_done on the channel
 * in order to receive the next message. This doesn't need to be immediate:
 * can be delayed if some processing is done on the message.
 *
 * @param cls Closure (set from #GNUNET_CADET_connect).
 * @param channel Connection to the other end.
 * @param channel_ctx Place to store local state associated with the channel.
 * @param message The actual message.
 * @return #GNUNET_OK to keep the channel open,
 *         #GNUNET_SYSERR to close it (signal serious error).
 */
typedef int
(*GNUNET_CADET_MessageCallback) (void *cls,
                                 struct GNUNET_CADET_Channel *channel,
                                 void **channel_ctx,
                                 const struct GNUNET_MessageHeader *message);


/**
 * Message handler.  Each struct specifies how to handle on particular
 * type of message received.
 */
struct GNUNET_CADET_MessageHandler
{
  /**
   * Function to call for messages of type @e type.
   */
  GNUNET_CADET_MessageCallback callback;

  /**
   * Type of the message this handler covers.
   */
  uint16_t type;

  /**
   * Expected size of messages of this type.  Use 0 for variable-size.
   * If non-zero, messages of the given type will be discarded if they
   * do not have the right size.
   */
  uint16_t expected_size;
};


/**
 * Method called whenever another peer has added us to a channel
 * the other peer initiated.
 * Only called (once) upon reception of data with a message type which was
 * subscribed to in #GNUNET_CADET_connect.
 *
 * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In
 * this case the handler MUST return NULL.
 *
 * @param cls closure
 * @param channel new handle to the channel
 * @param initiator peer that started the channel
 * @param port Port this channel is for.
 * @param options CadetOption flag field, with all active option bits set to 1.
 *
 * @return initial channel context for the channel
 *         (can be NULL -- that's not an error)
 */
typedef void *
(GNUNET_CADET_InboundChannelNotificationHandler) (void *cls,
                                                  struct GNUNET_CADET_Channel *channel,
                                                  const struct GNUNET_PeerIdentity *initiator,
                                                  uint32_t port,
                                                  enum GNUNET_CADET_ChannelOption options);


/**
 * Function called whenever a channel is destroyed.  Should clean up
 * any associated state.
 *
 * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
 *
 * @param cls closure (set from #GNUNET_CADET_connect)
 * @param channel connection to the other end (henceforth invalid)
 * @param channel_ctx place where local state associated
 *                   with the channel is stored
 */
typedef void
(GNUNET_CADET_ChannelEndHandler) (void *cls,
                                  const struct GNUNET_CADET_Channel *channel,
                                  void *channel_ctx);


/**
 * Connect to the cadet service.
 *
 * @param cfg Configuration to use.
 * @param cls Closure for the various callbacks that follow (including
 *            handlers in the handlers array).
 * @param new_channel Function called when an *incoming* channel is created.
 *                    Can be NULL if no inbound channels are desired.
 *                    See @a ports.
 * @param cleaner Function called when a channel is destroyed.
 *                It is called immediately if #GNUNET_CADET_channel_destroy
 *                is called on the channel.
 * @param handlers Callbacks for messages we care about, NULL-terminated. Each
 *                 one must call #GNUNET_CADET_receive_done on the channel to
 *                 receive the next message.  Messages of a type that is not
 *                 in the handlers array are ignored if received.
 * @param ports NULL or 0-terminated array of port numbers for incoming channels.
 *              See @a new_channel.
 *
 * @return handle to the cadet service NULL on error
 *         (in this case, init is never called)
 */
struct GNUNET_CADET_Handle *
GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
                      void *cls,
                      GNUNET_CADET_InboundChannelNotificationHandler new_channel,
                      GNUNET_CADET_ChannelEndHandler cleaner,
                      const struct GNUNET_CADET_MessageHandler *handlers,
                      const uint32_t *ports);


/**
 * Disconnect from the cadet service. All channels will be destroyed. All channel
 * disconnect callbacks will be called on any still connected peers, notifying
 * about their disconnection. The registered inbound channel cleaner will be
 * called should any inbound channels still exist.
 *
 * @param handle connection to cadet to disconnect
 */
void
GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);


/**
 * Create a new channel towards a remote peer.
 *
 * If the destination port is not open by any peer or the destination peer
 * does not accept the channel, #GNUNET_CADET_ChannelEndHandler will be called
 * for this channel.
 *
 * @param h cadet handle
 * @param channel_ctx client's channel context to associate with the channel
 * @param peer peer identity the channel should go to
 * @param port Port number.
 * @param options CadetOption flag field, with all desired option bits set to 1.
 *
 * @return handle to the channel
 */
struct GNUNET_CADET_Channel *
GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
                             void *channel_ctx,
                             const struct GNUNET_PeerIdentity *peer,
                             uint32_t port,
                             enum GNUNET_CADET_ChannelOption options);


/**
 * Destroy an existing channel.
 *
 * The existing end callback for the channel will be called immediately.
 * Any pending outgoing messages will be sent but no incoming messages will be
 * accepted and no data callbacks will be called.
 *
 * @param channel Channel handle, becomes invalid after this call.
 */
void
GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);


/**
 * Struct to retrieve info about a channel.
 */
union GNUNET_CADET_ChannelInfo
{

  /**
   * #GNUNET_YES / #GNUNET_NO, for binary flags.
   */
  int yes_no;

  /**
   * Peer on the other side of the channel
   */
  const struct GNUNET_PeerIdentity peer;
};


/**
 * Get information about a channel.
 *
 * @param channel Channel handle.
 * @param option Query type GNUNET_CADET_OPTION_*
 * @param ... dependant on option, currently not used
 * @return Union with an answer to the query.
 */
const union GNUNET_CADET_ChannelInfo *
GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
                              enum GNUNET_CADET_ChannelOption option, ...);


/**
 * Handle for a transmission request.
 */
struct GNUNET_CADET_TransmitHandle;


/**
 * Ask the cadet to call @a notify once it is ready to transmit the
 * given number of bytes to the specified channel.
 * Only one call can be active at any time, to issue another request,
 * wait for the callback or cancel the current request.
 *
 * @param channel channel to use for transmission
 * @param cork is corking allowed for this transmission?
 * @param maxdelay how long can the message wait?
 * @param notify_size how many bytes of buffer space does notify want?
 * @param notify function to call when buffer space is available;
 *        will be called with NULL on timeout or if the overall queue
 *        for this peer is larger than queue_size and this is currently
 *        the message with the lowest priority
 * @param notify_cls closure for @a notify
 * @return non-NULL if the notify callback was queued,
 *         NULL if we can not even queue the request (insufficient
 *         memory); if NULL is returned, @a notify will NOT be called.
 */
struct GNUNET_CADET_TransmitHandle *
GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel,
                                   int cork,
                                   struct GNUNET_TIME_Relative maxdelay,
                                   size_t notify_size,
                                   GNUNET_CONNECTION_TransmitReadyNotify notify,
                                   void *notify_cls);


/**
 * Cancel the specified transmission-ready notification.
 *
 * @param th handle that was returned by "notify_transmit_ready".
 */
void
GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th);


/**
 * Indicate readiness to receive the next message on a channel.
 *
 * Should only be called once per handler called.
 *
 * @param channel Channel that will be allowed to call another handler.
 */
void
GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);



/******************************************************************************/
/********************       MONITORING /DEBUG API     *************************/
/******************************************************************************/
/* The following calls are not useful for normal CADET operation, but for      */
/* debug and monitoring of the cadet state. They can be safely ignored.        */
/* The API can change at any point without notice.                            */
/* Please contact the developer if you consider any of this calls useful for  */
/* normal cadet applications.                                                  */
/******************************************************************************/


/**
 * Method called to retrieve information about a specific channel the cadet peer
 * is aware of, including all transit nodes.
 *
 * @param cls Closure.
 * @param root Root of the channel.
 * @param dest Destination of the channel.
 * @param port Destination port of the channel.
 * @param root_channel_number Local number for root, if known.
 * @param dest_channel_number Local number for dest, if known.
 * @param public_channel_numbe Number for P2P, always known.
 */
typedef void
(*GNUNET_CADET_ChannelCB) (void *cls,
                           const struct GNUNET_PeerIdentity *root,
                           const struct GNUNET_PeerIdentity *dest,
                           uint32_t port,
                           uint32_t root_channel_number,
                           uint32_t dest_channel_number,
                           uint32_t public_channel_number);

/**
 * Method called to retrieve information about all peers in CADET, called
 * once per peer.
 *
 * After last peer has been reported, an additional call with NULL is done.
 *
 * @param cls Closure.
 * @param peer Peer, or NULL on "EOF".
 * @param tunnel Do we have a tunnel towards this peer?
 * @param n_paths Number of known paths towards this peer.
 * @param best_path How long is the best path?
 *                  (0 = unknown, 1 = ourselves, 2 = neighbor)
 */
typedef void
(*GNUNET_CADET_PeersCB) (void *cls,
                         const struct GNUNET_PeerIdentity *peer,
                         int tunnel,
                         unsigned int n_paths,
                         unsigned int best_path);

/**
 * Method called to retrieve information about a specific peer
 * known to the service.
 *
 * @param cls Closure.
 * @param peer Peer ID.
 * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO
 * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO
 * @param n_paths Number of paths known towards peer.
 * @param paths Array of PEER_IDs representing all paths to reach the peer.
 *              Each path starts with the local peer.
 *              Each path ends with the destination peer (given in @c peer).
 */
typedef void
(*GNUNET_CADET_PeerCB) (void *cls,
                        const struct GNUNET_PeerIdentity *peer,
                        int tunnel,
                        int neighbor,
                        unsigned int n_paths,
                        struct GNUNET_PeerIdentity *paths);


/**
 * Method called to retrieve information about all tunnels in CADET, called
 * once per tunnel.
 *
 * After last tunnel has been reported, an additional call with NULL is done.
 *
 * @param cls Closure.
 * @param peer Destination peer, or NULL on "EOF".
 * @param channels Number of channels.
 * @param connections Number of connections.
 * @param estate Encryption state.
 * @param cstate Connectivity state.
 */
typedef void
(*GNUNET_CADET_TunnelsCB) (void *cls,
                           const struct GNUNET_PeerIdentity *peer,
                           unsigned int channels,
                           unsigned int connections,
                           uint16_t estate,
                           uint16_t cstate);


/**
 * Method called to retrieve information about a specific tunnel the cadet peer
 * has established, o`r is trying to establish.
 *
 * @param cls Closure.
 * @param peer Peer towards whom the tunnel is directed.
 * @param n_channels Number of channels.
 * @param n_connections Number of connections.
 * @param channels Channels.
 * @param connections Connections.
 * @param estate Encryption state.
 * @param cstate Connectivity state.
 */
typedef void
(*GNUNET_CADET_TunnelCB) (void *cls,
                          const struct GNUNET_PeerIdentity *peer,
                          unsigned int n_channels,
                          unsigned int n_connections,
                          uint32_t *channels,
                          struct GNUNET_CADET_Hash *connections,
                          unsigned int estate,
                          unsigned int cstate);


/**
 * Request information about a specific channel of the running cadet peer.
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Handle to the cadet peer.
 * @param peer ID of the other end of the channel.
 * @param channel_number Channel number.
 * @param callback Function to call with the requested data.
 * @param callback_cls Closure for @c callback.
 */
void
GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h,
                          struct GNUNET_PeerIdentity *peer,
                          uint32_t channel_number,
                          GNUNET_CADET_ChannelCB callback,
                          void *callback_cls);


/**
 * Request a debug dump on the service's STDERR.
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h cadet handle
 */
void
GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h);


/**
 * Request information about peers known to the running cadet service.
 * The callback will be called for every peer known to the service.
 * Only one info request (of any kind) can be active at once.
 *
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Handle to the cadet peer.
 * @param callback Function to call with the requested data.
 * @param callback_cls Closure for @c callback.
 *
 * @return #GNUNET_OK / #GNUNET_SYSERR
 */
int
GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h,
                        GNUNET_CADET_PeersCB callback,
                        void *callback_cls);


/**
 * Cancel a peer info request. The callback will not be called (anymore).
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Cadet handle.
 *
 * @return Closure that was given to #GNUNET_CADET_get_peers().
 */
void *
GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h);


/**
 * Request information about a peer known to the running cadet peer.
 * The callback will be called for the tunnel once.
 * Only one info request (of any kind) can be active at once.
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Handle to the cadet peer.
 * @param id Peer whose tunnel to examine.
 * @param callback Function to call with the requested data.
 * @param callback_cls Closure for @c callback.
 *
 * @return #GNUNET_OK / #GNUNET_SYSERR
 */
int
GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h,
                      const struct GNUNET_PeerIdentity *id,
                      GNUNET_CADET_PeerCB callback,
                      void *callback_cls);


/**
 * Request information about tunnels of the running cadet peer.
 * The callback will be called for every tunnel of the service.
 * Only one info request (of any kind) can be active at once.
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Handle to the cadet peer.
 * @param callback Function to call with the requested data.
 * @param callback_cls Closure for @c callback.
 *
 * @return #GNUNET_OK / #GNUNET_SYSERR
 */
int
GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h,
                          GNUNET_CADET_TunnelsCB callback,
                          void *callback_cls);


/**
 * Cancel a monitor request. The monitor callback will not be called.
 *
 * @param h Cadet handle.
 *
 * @return Closure given to #GNUNET_CADET_get_tunnels(), if any.
 */
void *
GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h);


/**
 * Request information about a tunnel of the running cadet peer.
 * The callback will be called for the tunnel once.
 * Only one info request (of any kind) can be active at once.
 *
 * WARNING: unstable API, likely to change in the future!
 *
 * @param h Handle to the cadet peer.
 * @param id Peer whose tunnel to examine.
 * @param callback Function to call with the requested data.
 * @param callback_cls Closure for @c callback.
 *
 * @return #GNUNET_OK / #GNUNET_SYSERR
 */
int
GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h,
                         const struct GNUNET_PeerIdentity *id,
                         GNUNET_CADET_TunnelCB callback,
                         void *callback_cls);


/**
 * Create a message queue for a cadet channel.
 * The message queue can only be used to transmit messages,
 * not to receive them.
 *
 * @param channel the channel to create the message qeue for
 * @return a message queue to messages over the channel
 */
struct GNUNET_MQ_Handle *
GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel);


#if 0                           /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif

/* ifndef GNUNET_CADET_SERVICE_H */
#endif
/* end of gnunet_cadet_service.h */