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22 * @file cadet/gnunet-service-cadet_connection.h
23 * @brief cadet service; dealing with connections
24 * @author Bartlomiej Polot
26 * All functions in this file should use the prefix GMC (Gnunet Cadet Connection)
29 #ifndef GNUNET_SERVICE_CADET_CONNECTION_H
30 #define GNUNET_SERVICE_CADET_CONNECTION_H
35 #if 0 /* keep Emacsens' auto-indent happy */
40 #include "gnunet_util_lib.h"
44 * All the states a connection can be in.
46 enum CadetConnectionState
49 * Uninitialized status, should never appear in operation.
54 * Connection create message sent, waiting for ACK.
56 CADET_CONNECTION_SENT,
59 * Connection ACK sent, waiting for ACK.
64 * Connection confirmed, ready to carry traffic.
66 CADET_CONNECTION_READY,
69 * Connection to be destroyed, just waiting to empty queues.
71 CADET_CONNECTION_DESTROYED,
74 * Connection to be destroyed because of a distant peer, same as DESTROYED.
76 CADET_CONNECTION_BROKEN,
81 * Struct containing all information regarding a connection to a peer.
83 struct CadetConnection;
86 * Handle for messages queued but not yet sent.
88 struct CadetConnectionQueue;
90 #include "cadet_path.h"
91 #include "gnunet-service-cadet_channel.h"
92 #include "gnunet-service-cadet_peer.h"
96 * Check invariants for all connections using #check_neighbours().
99 GCC_check_connections ();
103 * Callback called when a queued message is sent.
105 * @param cls Closure.
106 * @param c Connection this message was on.
107 * @param type Type of message sent.
108 * @param fwd Was this a FWD going message?
109 * @param size Size of the message.
112 (*GCC_sent) (void *cls,
113 struct CadetConnection *c,
114 struct CadetConnectionQueue *q,
121 * Core handler for connection creation.
123 * @param cls Closure (unused).
124 * @param peer Sender (neighbor).
125 * @param message Message.
126 * @return #GNUNET_OK to keep the connection open,
127 * #GNUNET_SYSERR to close it (signal serious error)
130 GCC_handle_create (void *cls,
131 const struct GNUNET_PeerIdentity *peer,
132 const struct GNUNET_MessageHeader *message);
136 * Core handler for path confirmations.
139 * @param message message
140 * @param peer peer identity this notification is about
141 * @return #GNUNET_OK to keep the connection open,
142 * #GNUNET_SYSERR to close it (signal serious error)
145 GCC_handle_confirm (void *cls,
146 const struct GNUNET_PeerIdentity *peer,
147 const struct GNUNET_MessageHeader *message);
151 * Core handler for notifications of broken paths
153 * @param cls Closure (unused).
154 * @param id Peer identity of sending neighbor.
155 * @param message Message.
156 * @return #GNUNET_OK to keep the connection open,
157 * #GNUNET_SYSERR to close it (signal serious error)
160 GCC_handle_broken (void* cls,
161 const struct GNUNET_PeerIdentity* id,
162 const struct GNUNET_MessageHeader* message);
165 * Core handler for tunnel destruction
167 * @param cls Closure (unused).
168 * @param peer Peer identity of sending neighbor.
169 * @param message Message.
171 * @return GNUNET_OK to keep the connection open,
172 * GNUNET_SYSERR to close it (signal serious error)
175 GCC_handle_destroy (void *cls, const struct GNUNET_PeerIdentity *peer,
176 const struct GNUNET_MessageHeader *message);
179 * Core handler for key exchange traffic (ephemeral key, ping, pong).
181 * @param cls Closure (unused).
182 * @param message Message received.
183 * @param peer Peer who sent the message.
185 * @return GNUNET_OK to keep the connection open,
186 * GNUNET_SYSERR to close it (signal serious error)
189 GCC_handle_kx (void *cls, const struct GNUNET_PeerIdentity *peer,
190 const struct GNUNET_MessageHeader *message);
193 * Core handler for encrypted cadet network traffic (channel mgmt, data).
195 * @param cls Closure (unused).
196 * @param message Message received.
197 * @param peer Peer who sent the message.
199 * @return GNUNET_OK to keep the connection open,
200 * GNUNET_SYSERR to close it (signal serious error)
203 GCC_handle_encrypted (void *cls, const struct GNUNET_PeerIdentity *peer,
204 const struct GNUNET_MessageHeader *message);
207 * Core handler for axolotl key exchange traffic.
209 * @param cls Closure (unused).
210 * @param message Message received.
211 * @param peer Neighbor who sent the message.
213 * @return GNUNET_OK, to keep the connection open.
216 GCC_handle_ax_kx (void *cls, const struct GNUNET_PeerIdentity *peer,
217 const struct GNUNET_MessageHeader *message);
220 * Core handler for axolotl encrypted cadet network traffic.
222 * @param cls Closure (unused).
223 * @param message Message received.
224 * @param peer Neighbor who sent the message.
226 * @return GNUNET_OK, to keep the connection open.
229 GCC_handle_ax (void *cls, const struct GNUNET_PeerIdentity *peer,
230 struct GNUNET_MessageHeader *message);
233 * Core handler for cadet network traffic point-to-point acks.
236 * @param message message
237 * @param peer peer identity this notification is about
239 * @return GNUNET_OK to keep the connection open,
240 * GNUNET_SYSERR to close it (signal serious error)
243 GCC_handle_ack (void *cls, const struct GNUNET_PeerIdentity *peer,
244 const struct GNUNET_MessageHeader *message);
247 * Core handler for cadet network traffic point-to-point ack polls.
250 * @param message message
251 * @param peer peer identity this notification is about
253 * @return GNUNET_OK to keep the connection open,
254 * GNUNET_SYSERR to close it (signal serious error)
257 GCC_handle_poll (void *cls, const struct GNUNET_PeerIdentity *peer,
258 const struct GNUNET_MessageHeader *message);
261 * Core handler for cadet keepalives.
264 * @param message message
265 * @param peer peer identity this notification is about
266 * @return GNUNET_OK to keep the connection open,
267 * GNUNET_SYSERR to close it (signal serious error)
269 * TODO: Check who we got this from, to validate route.
272 GCC_handle_keepalive (void *cls, const struct GNUNET_PeerIdentity *peer,
273 const struct GNUNET_MessageHeader *message);
276 * Send an ACK on the appropriate connection/channel, depending on
277 * the direction and the position of the peer.
279 * @param c Which connection to send the hop-by-hop ACK.
280 * @param fwd Is this a fwd ACK? (will go dest->root).
281 * @param force Send the ACK even if suboptimal (e.g. requested by POLL).
284 GCC_send_ack (struct CadetConnection *c, int fwd, int force);
287 * Initialize the connections subsystem
289 * @param c Configuration handle.
292 GCC_init (const struct GNUNET_CONFIGURATION_Handle *c);
295 * Shut down the connections subsystem.
301 * Create a connection.
303 * @param cid Connection ID (either created locally or imposed remotely).
304 * @param t Tunnel this connection belongs to (or NULL);
305 * @param path Path this connection has to use (copy is made).
306 * @param own_pos Own position in the @c path path.
308 * @return Newly created connection, NULL in case of error (own id not in path).
310 struct CadetConnection *
311 GCC_new (const struct GNUNET_CADET_Hash *cid,
312 struct CadetTunnel *t,
313 struct CadetPeerPath *path,
314 unsigned int own_pos);
317 * Connection is no longer needed: destroy it.
319 * Cancels all pending traffic (including possible DESTROY messages), all
320 * maintenance tasks and removes the connection from neighbor peers and tunnel.
322 * @param c Connection to destroy.
325 GCC_destroy (struct CadetConnection *c);
328 * Get the connection ID.
330 * @param c Connection to get the ID from.
332 * @return ID of the connection.
334 const struct GNUNET_CADET_Hash *
335 GCC_get_id (const struct CadetConnection *c);
339 * Get a hash for the connection ID.
341 * @param c Connection to get the hash.
343 * @return Hash expanded from the ID of the connection.
345 const struct GNUNET_HashCode *
346 GCC_get_h (const struct CadetConnection *c);
350 * Get the connection path.
352 * @param c Connection to get the path from.
354 * @return path used by the connection.
356 const struct CadetPeerPath *
357 GCC_get_path (const struct CadetConnection *c);
360 * Get the connection state.
362 * @param c Connection to get the state from.
364 * @return state of the connection.
366 enum CadetConnectionState
367 GCC_get_state (const struct CadetConnection *c);
370 * Get the connection tunnel.
372 * @param c Connection to get the tunnel from.
374 * @return tunnel of the connection.
377 GCC_get_tunnel (const struct CadetConnection *c);
380 * Get free buffer space in a connection.
382 * @param c Connection.
383 * @param fwd Is query about FWD traffic?
385 * @return Free buffer space [0 - max_msgs_queue/max_connections]
388 GCC_get_buffer (struct CadetConnection *c, int fwd);
391 * Get how many messages have we allowed to send to us from a direction.
393 * @param c Connection.
394 * @param fwd Are we asking about traffic from FWD (BCK messages)?
396 * @return last_ack_sent - last_pid_recv
399 GCC_get_allowed (struct CadetConnection *c, int fwd);
402 * Get messages queued in a connection.
404 * @param c Connection.
405 * @param fwd Is query about FWD traffic?
407 * @return Number of messages queued.
410 GCC_get_qn (struct CadetConnection *c, int fwd);
413 * Get next PID to use.
415 * @param c Connection.
416 * @param fwd Is query about FWD traffic?
418 * @return Last PID used + 1.
421 GCC_get_pid (struct CadetConnection *c, int fwd);
424 * Allow the connection to advertise a buffer of the given size.
426 * The connection will send an @c fwd ACK message (so: in direction !fwd)
427 * allowing up to last_pid_recv + buffer.
429 * @param c Connection.
430 * @param buffer How many more messages the connection can accept.
431 * @param fwd Is this about FWD traffic? (The ack will go dest->root).
434 GCC_allow (struct CadetConnection *c, unsigned int buffer, int fwd);
437 * Send FWD keepalive packets for a connection.
439 * @param cls Closure (connection for which to send the keepalive).
440 * @param tc Notification context.
443 GCC_fwd_keepalive (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
446 * Send BCK keepalive packets for a connection.
448 * @param cls Closure (connection for which to send the keepalive).
449 * @param tc Notification context.
452 GCC_bck_keepalive (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
456 * Notify other peers on a connection of a broken link. Mark connections
457 * to destroy after all traffic has been sent.
459 * @param c Connection on which there has been a disconnection.
460 * @param peer Peer that disconnected.
463 GCC_neighbor_disconnected (struct CadetConnection *c, struct CadetPeer *peer);
466 * Is this peer the first one on the connection?
468 * @param c Connection.
469 * @param fwd Is this about fwd traffic?
471 * @return #GNUNET_YES if origin, #GNUNET_NO if relay/terminal.
474 GCC_is_origin (struct CadetConnection *c, int fwd);
477 * Is this peer the last one on the connection?
479 * @param c Connection.
480 * @param fwd Is this about fwd traffic?
481 * Note that the ROOT is the terminal for BCK traffic!
483 * @return #GNUNET_YES if terminal, #GNUNET_NO if relay/origin.
486 GCC_is_terminal (struct CadetConnection *c, int fwd);
489 * See if we are allowed to send by the next hop in the given direction.
491 * @param c Connection.
492 * @param fwd Is this about fwd traffic?
494 * @return #GNUNET_YES in case it's OK to send.
497 GCC_is_sendable (struct CadetConnection *c, int fwd);
500 * Check if this connection is a direct one (never trim a direct connection).
502 * @param c Connection.
504 * @return #GNUNET_YES in case it's a direct connection, #GNUNET_NO otherwise.
507 GCC_is_direct (struct CadetConnection *c);
510 * Cancel a previously sent message while it's in the queue.
512 * ONLY can be called before the continuation given to the send function
513 * is called. Once the continuation is called, the message is no longer in the
516 * @param q Handle to the queue.
519 GCC_cancel (struct CadetConnectionQueue *q);
522 * Sends an already built message on a connection, properly registering
523 * all used resources.
525 * @param message Message to send. Function makes a copy of it.
526 * If message is not hop-by-hop, decrements TTL of copy.
527 * @param payload_type Type of payload, in case the message is encrypted.
528 * @param c Connection on which this message is transmitted.
529 * @param fwd Is this a fwd message?
530 * @param force Force the connection to accept the message (buffer overfill).
531 * @param cont Continuation called once message is sent. Can be NULL.
532 * @param cont_cls Closure for @c cont.
534 * @return Handle to cancel the message before it's sent.
535 * NULL on error or if @c cont is NULL.
536 * Invalid on @c cont call.
538 struct CadetConnectionQueue *
539 GCC_send_prebuilt_message (const struct GNUNET_MessageHeader *message,
540 uint16_t payload_type, uint32_t payload_id,
541 struct CadetConnection *c, int fwd, int force,
542 GCC_sent cont, void *cont_cls);
545 * Sends a CREATE CONNECTION message for a path to a peer.
546 * Changes the connection and tunnel states if necessary.
548 * @param connection Connection to create.
551 GCC_send_create (struct CadetConnection *connection);
554 * Send a message to all peers in this connection that the connection
555 * is no longer valid.
557 * If some peer should not receive the message, it should be zero'ed out
558 * before calling this function.
560 * @param c The connection whose peers to notify.
563 GCC_send_destroy (struct CadetConnection *c);
566 * @brief Start a polling timer for the connection.
568 * When a neighbor does not accept more traffic on the connection it could be
569 * caused by a simple congestion or by a lost ACK. Polling enables to check
570 * for the lastest ACK status for a connection.
572 * @param c Connection.
573 * @param fwd Should we poll in the FWD direction?
576 GCC_start_poll (struct CadetConnection *c, int fwd);
580 * @brief Stop polling a connection for ACKs.
582 * Once we have enough ACKs for future traffic, polls are no longer necessary.
584 * @param c Connection.
585 * @param fwd Should we stop the poll in the FWD direction?
588 GCC_stop_poll (struct CadetConnection *c, int fwd);
591 * Get a (static) string for a connection.
593 * @param c Connection.
596 GCC_2s (const struct CadetConnection *c);
599 * Log all possible info about the connection state.
601 * @param c Connection to debug.
602 * @param level Debug level to use.
605 GCC_debug (const struct CadetConnection *c, enum GNUNET_ErrorType level);
607 #if 0 /* keep Emacsens' auto-indent happy */
614 /* ifndef GNUNET_SERVICE_CADET_CONNECTION_H */
616 /* end of gnunet-service-cadet_connection.h */