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3 (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_transport_service.h
23 * @brief low-level P2P IO
24 * @author Christian Grothoff
27 #ifndef GNUNET_TRANSPORT_SERVICE_H
28 #define GNUNET_TRANSPORT_SERVICE_H
33 #if 0 /* keep Emacsens' auto-indent happy */
38 #include "gnunet_util_lib.h"
39 #include "gnunet_ats_service.h"
42 * Version number of the transport API.
44 #define GNUNET_TRANSPORT_VERSION 0x00000000
48 * Possible state of a neighbour. Initially, we are #S_NOT_CONNECTED.
50 * Then, there are two main paths. If we receive a CONNECT message, we
51 * first run a check against the blacklist (#S_CONNECT_RECV_BLACKLIST_INBOUND).
52 * If this check is successful, we give the inbound address to ATS.
53 * After the check we ask ATS for a suggestion (S_CONNECT_RECV_ATS).
54 * If ATS makes a suggestion, we ALSO give that suggestion to the blacklist
55 * (#S_CONNECT_RECV_BLACKLIST). Once the blacklist approves the
56 * address we got from ATS, we send our CONNECT_ACK and go to
57 * #S_CONNECT_RECV_ACK. If we receive a SESSION_ACK, we go to
58 * #S_CONNECTED (and notify everyone about the new connection). If the
59 * operation times out, we go to #S_DISCONNECT.
61 * The other case is where we transmit a CONNECT message first. We
62 * start with #S_INIT_ATS. If we get an address, we enter
63 * #S_INIT_BLACKLIST and check the blacklist. If the blacklist is OK
64 * with the connection, we actually send the CONNECT message and go to
65 * state S_CONNECT_SENT. Once we receive a CONNECT_ACK, we go to
66 * #S_CONNECTED (and notify everyone about the new connection and send
67 * back a SESSION_ACK). If the operation times out, we go to
70 * If the session is in trouble (i.e. transport-level disconnect or
71 * timeout), we go to #S_RECONNECT_ATS where we ask ATS for a new
72 * address (we don't notify anyone about the disconnect yet). Once we
73 * have a new address, we go to #S_RECONNECT_BLACKLIST to check the new
74 * address against the blacklist. If the blacklist approves, we enter
75 * #S_RECONNECT_SENT and send a CONNECT message. If we receive a
76 * CONNECT_ACK, we go to #S_CONNECTED and nobody noticed that we had
77 * trouble; we also send a SESSION_ACK at this time just in case. If
78 * the operation times out, we go to S_DISCONNECT (and notify everyone
79 * about the lost connection).
81 * If ATS decides to switch addresses while we have a normal
82 * connection, we go to #S_CONNECTED_SWITCHING_BLACKLIST to check the
83 * new address against the blacklist. If the blacklist approves, we
84 * go to #S_CONNECTED_SWITCHING_CONNECT_SENT and send a
85 * SESSION_CONNECT. If we get a SESSION_ACK back, we switch the
86 * primary connection to the suggested alternative from ATS, go back
87 * to #S_CONNECTED and send a SESSION_ACK to the other peer just to be
88 * sure. If the operation times out (or the blacklist disapproves),
89 * we go to #S_CONNECTED (and notify ATS that the given alternative
90 * address is "invalid").
92 * Once a session is in #S_DISCONNECT, it is cleaned up and then goes
93 * to (#S_DISCONNECT_FINISHED). If we receive an explicit disconnect
94 * request, we can go from any state to #S_DISCONNECT, possibly after
95 * generating disconnect notifications.
97 * Note that it is quite possible that while we are in any of these
98 * states, we could receive a 'CONNECT' request from the other peer.
99 * We then enter a 'weird' state where we pursue our own primary state
100 * machine (as described above), but with the 'send_connect_ack' flag
101 * set to 1. If our state machine allows us to send a 'CONNECT_ACK'
102 * (because we have an acceptable address), we send the 'CONNECT_ACK'
103 * and set the 'send_connect_ack' to 2. If we then receive a
104 * 'SESSION_ACK', we go to #S_CONNECTED (and reset 'send_connect_ack'
108 enum GNUNET_TRANSPORT_PeerState
111 * fresh peer or completely disconnected
113 GNUNET_TRANSPORT_NOT_CONNECTED = 0,
116 * Asked to initiate connection, trying to get address from ATS
118 GNUNET_TRANSPORT_INIT_ATS,
121 * Asked to initiate connection, trying to get address approved
124 GNUNET_TRANSPORT_INIT_BLACKLIST,
127 * Sent CONNECT message to other peer, waiting for CONNECT_ACK
129 GNUNET_TRANSPORT_CONNECT_SENT,
132 * Received a CONNECT, do a blacklist check for inbound address
134 GNUNET_TRANSPORT_CONNECT_RECV_BLACKLIST_INBOUND,
137 * Received a CONNECT, asking ATS about address suggestions.
139 GNUNET_TRANSPORT_CONNECT_RECV_ATS,
142 * Received CONNECT from other peer, got an address, checking with blacklist.
144 GNUNET_TRANSPORT_CONNECT_RECV_BLACKLIST,
147 * CONNECT request from other peer was SESSION_ACK'ed, waiting for
150 GNUNET_TRANSPORT_CONNECT_RECV_ACK,
153 * Got our CONNECT_ACK/SESSION_ACK, connection is up.
155 GNUNET_TRANSPORT_CONNECTED,
158 * Connection got into trouble, rest of the system still believes
159 * it to be up, but we're getting a new address from ATS.
161 GNUNET_TRANSPORT_RECONNECT_ATS,
164 * Connection got into trouble, rest of the system still believes
165 * it to be up; we are checking the new address against the blacklist.
167 GNUNET_TRANSPORT_RECONNECT_BLACKLIST,
170 * Sent CONNECT over new address (either by ATS telling us to switch
171 * addresses or from RECONNECT_ATS); if this fails, we need to tell
172 * the rest of the system about a disconnect.
174 GNUNET_TRANSPORT_RECONNECT_SENT,
177 * We have some primary connection, but ATS suggested we switch
178 * to some alternative; we're now checking the alternative against
181 GNUNET_TRANSPORT_CONNECTED_SWITCHING_BLACKLIST,
184 * We have some primary connection, but ATS suggested we switch
185 * to some alternative; we now sent a CONNECT message for the
186 * alternative session to the other peer and waiting for a
187 * CONNECT_ACK to make this our primary connection.
189 GNUNET_TRANSPORT_CONNECTED_SWITCHING_CONNECT_SENT,
192 * Disconnect in progress (we're sending the DISCONNECT message to the
193 * other peer; after that is finished, the state will be cleaned up).
195 GNUNET_TRANSPORT_DISCONNECT,
198 * We're finished with the disconnect; and are cleaning up the state
199 * now! We put the struct into this state when we are really in the
200 * task that calls 'free' on it and are about to remove the record
201 * from the map. We should never find a 'struct NeighbourMapEntry'
202 * in this state in the map. Accessing a 'struct NeighbourMapEntry'
203 * in this state virtually always means using memory that has been
204 * freed (the exception being the cleanup code in #free_neighbour()).
206 GNUNET_TRANSPORT_DISCONNECT_FINISHED
212 * Function called by the transport for each received message.
215 * @param peer (claimed) identity of the other peer
216 * @param message the message
217 * @param ats performance data
218 * @param ats_count number of entries in ats
220 typedef void (*GNUNET_TRANSPORT_ReceiveCallback) (void *cls,
222 GNUNET_PeerIdentity * peer,
224 GNUNET_MessageHeader *
229 * Opaque handle to the service.
231 struct GNUNET_TRANSPORT_Handle;
235 * Function called to notify transport users that another
236 * peer connected to us.
239 * @param peer the peer that connected
240 * @param ats performance data
241 * @param ats_count number of entries in ats (excluding 0-termination)
243 typedef void (*GNUNET_TRANSPORT_NotifyConnect) (void *cls,
244 const struct GNUNET_PeerIdentity
248 * Function called to notify transport users that another
249 * peer disconnected from us.
252 * @param peer the peer that disconnected
254 typedef void (*GNUNET_TRANSPORT_NotifyDisconnect) (void *cls,
256 GNUNET_PeerIdentity * peer);
260 * Function to call with result of the try connect request.
264 * @param result GNUNET_OK if message was transmitted to transport service
265 * GNUNET_SYSERR if message was not transmitted to transport service
267 typedef void (*GNUNET_TRANSPORT_TryConnectCallback) (void *cls,
272 * Function to call with a textual representation of an address.
273 * This function will be called several times with different possible
274 * textual representations, and a last time with NULL to signal the end
278 * @param address NULL on error or end of iteration,
279 * otherwise 0-terminated printable UTF-8 string
281 typedef void (*GNUNET_TRANSPORT_AddressToStringCallback) (void *cls,
282 const char *address);
286 * Function to call with information about a peer
288 * If one_shot was set to GNUNET_YES to iterate over all peers once,
289 * a final call with NULL for peer and address will follow when done
291 * The #GNUNET_TRANSPORT_monitor_peers_cancel call MUST not be called from
292 * within this function!
296 * @param peer peer this update is about,
297 * NULL if this is the final last callback for a iteration operation
298 * @param address address, NULL for disconnect notification in monitor mode
299 * @param state current state this peer is in
300 * @param state_timeout timeout for the current state of the peer
302 typedef void (*GNUNET_TRANSPORT_PeerIterateCallback) (void *cls,
303 const struct GNUNET_PeerIdentity *peer,
304 const struct GNUNET_HELLO_Address *address,
305 enum GNUNET_TRANSPORT_PeerState state,
306 struct GNUNET_TIME_Absolute state_timeout);
310 * Function to call with validation information about a peer
313 * @param peer peer this update is about,
314 * NULL if this is the final last callback for a iteration operation
315 * @param address address, NULL for disconnect notification in monitor mode
316 * @param valid_until when does this address expire
317 * @param next_validation time of the next validation operation
320 typedef void (*GNUNET_TRANSPORT_ValidationIterateCallback) (void *cls,
321 const struct GNUNET_PeerIdentity *peer,
322 const struct GNUNET_HELLO_Address *address,
323 struct GNUNET_TIME_Absolute valid_until,
324 struct GNUNET_TIME_Absolute next_validation);
329 * Connect to the transport service. Note that the connection may
330 * complete (or fail) asynchronously.
332 * @param cfg configuration to use
333 * @param self our own identity (API should check that it matches
334 * the identity found by transport), or NULL (no check)
335 * @param cls closure for the callbacks
336 * @param rec receive function to call, or NULL
337 * @param nc function to call on connect events, or NULL
338 * @param nd function to call on disconnect events, or NULL
339 * @return NULL on error
341 struct GNUNET_TRANSPORT_Handle *
342 GNUNET_TRANSPORT_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
343 const struct GNUNET_PeerIdentity *self, void *cls,
344 GNUNET_TRANSPORT_ReceiveCallback rec,
345 GNUNET_TRANSPORT_NotifyConnect nc,
346 GNUNET_TRANSPORT_NotifyDisconnect nd);
350 * Disconnect from the transport service.
352 * @param handle handle returned from connect
355 GNUNET_TRANSPORT_disconnect (struct GNUNET_TRANSPORT_Handle *handle);
359 * Opaque handle for a transmission-ready request.
361 struct GNUNET_TRANSPORT_TryConnectHandle;
365 * Ask the transport service to establish a connection to
368 * @param handle connection to transport service
369 * @param target who we should try to connect to
370 * @param cb callback to be called when request was transmitted to transport
372 * @param cb_cls closure for the callback
373 * @return a GNUNET_TRANSPORT_TryConnectHandle handle or
374 * NULL on failure (cb will not be called)
376 struct GNUNET_TRANSPORT_TryConnectHandle *
377 GNUNET_TRANSPORT_try_connect (struct GNUNET_TRANSPORT_Handle *handle,
378 const struct GNUNET_PeerIdentity *target,
379 GNUNET_TRANSPORT_TryConnectCallback cb,
384 * Cancel the request to transport to try a connect
385 * Callback will not be called
387 * @param tch GNUNET_TRANSPORT_TryConnectHandle handle to cancel
390 GNUNET_TRANSPORT_try_connect_cancel (struct GNUNET_TRANSPORT_TryConnectHandle *tch);
394 * Opaque handle for a transmission-ready request.
396 struct GNUNET_TRANSPORT_TransmitHandle;
400 * Check if we could queue a message of the given size for
401 * transmission. The transport service will take both its internal
402 * buffers and bandwidth limits imposed by the other peer into
403 * consideration when answering this query.
405 * @param handle connection to transport service
406 * @param target who should receive the message
407 * @param size how big is the message we want to transmit?
408 * @param priority how important is the message? @deprecated - remove?
409 * @param timeout after how long should we give up (and call
410 * notify with buf NULL and size 0)?
411 * @param notify function to call when we are ready to
412 * send such a message
413 * @param notify_cls closure for notify
414 * @return NULL if someone else is already waiting to be notified
415 * non-NULL if the notify callback was queued (can be used to cancel
416 * using GNUNET_TRANSPORT_notify_transmit_ready_cancel)
418 struct GNUNET_TRANSPORT_TransmitHandle *
419 GNUNET_TRANSPORT_notify_transmit_ready (struct GNUNET_TRANSPORT_Handle *handle,
420 const struct GNUNET_PeerIdentity
421 *target, size_t size, uint32_t priority,
422 struct GNUNET_TIME_Relative timeout,
423 GNUNET_CONNECTION_TransmitReadyNotify
424 notify, void *notify_cls);
428 * Cancel the specified transmission-ready notification.
430 * @param th handle of the transmission notification request to cancel
433 GNUNET_TRANSPORT_notify_transmit_ready_cancel (struct
434 GNUNET_TRANSPORT_TransmitHandle
440 * Function called whenever there is an update to the
441 * HELLO of this peer.
444 * @param hello our updated HELLO
446 typedef void (*GNUNET_TRANSPORT_HelloUpdateCallback) (void *cls,
448 GNUNET_MessageHeader *
453 * Handle to cancel a 'GNUNET_TRANSPORT_get_hello' operation.
455 struct GNUNET_TRANSPORT_GetHelloHandle;
459 * Checks if a given peer is connected to us
461 * @param handle connection to transport service
462 * @param peer the peer to check
463 * @return #GNUNET_YES (connected) or #GNUNET_NO (disconnected)
466 GNUNET_TRANSPORT_check_peer_connected (struct GNUNET_TRANSPORT_Handle *handle,
467 const struct GNUNET_PeerIdentity *peer);
471 * Set transport metrics for a peer and a direction
473 * @param handle transport handle
474 * @param peer the peer to set the metric for
475 * @param inbound set inbound direction (GNUNET_YES or GNUNET_NO)
476 * @param outbound set outbound direction (GNUNET_YES or GNUNET_NO)
477 * @param ats the metric as ATS information
478 * @param ats_count the number of metrics
480 * Supported ATS values:
481 * GNUNET_ATS_QUALITY_NET_DELAY (value in ms)
482 * GNUNET_ATS_QUALITY_NET_DISTANCE (value in count(hops))
485 * To enforce a delay of 10 ms for peer p1 in sending direction use:
487 * struct GNUNET_ATS_Information ats;
488 * ats.type = ntohl (GNUNET_ATS_QUALITY_NET_DELAY);
489 * ats.value = ntohl (10);
490 * GNUNET_TRANSPORT_set_traffic_metric (th, p1, TM_SEND, &ats, 1);
493 * Delay restrictions in receiving direction will be enforced with
497 GNUNET_TRANSPORT_set_traffic_metric (struct GNUNET_TRANSPORT_Handle *handle,
498 const struct GNUNET_PeerIdentity *peer,
501 const struct GNUNET_ATS_Information *ats,
506 * Obtain updates on changes to the HELLO message for this peer. The callback
507 * given in this function is never called synchronously.
509 * @param handle connection to transport service
510 * @param rec function to call with the HELLO
511 * @param rec_cls closure for rec
512 * @return handle to cancel the operation
514 struct GNUNET_TRANSPORT_GetHelloHandle *
515 GNUNET_TRANSPORT_get_hello (struct GNUNET_TRANSPORT_Handle *handle,
516 GNUNET_TRANSPORT_HelloUpdateCallback rec,
521 * Stop receiving updates about changes to our HELLO message.
523 * @param ghh handle to cancel
526 GNUNET_TRANSPORT_get_hello_cancel (struct GNUNET_TRANSPORT_GetHelloHandle *ghh);
530 * Offer the transport service the HELLO of another peer. Note that
531 * the transport service may just ignore this message if the HELLO is
532 * malformed or useless due to our local configuration.
534 * @param handle connection to transport service
535 * @param hello the hello message
536 * @param cont continuation to call when HELLO has been sent,
537 * tc reason GNUNET_SCHEDULER_REASON_TIMEOUT for fail
538 * tc reasong GNUNET_SCHEDULER_REASON_READ_READY for success
539 * @param cls closure for continuation
540 * @return a GNUNET_TRANSPORT_OfferHelloHandle handle or NULL on failure,
541 * in case of failure cont will not be called
544 struct GNUNET_TRANSPORT_OfferHelloHandle *
545 GNUNET_TRANSPORT_offer_hello (struct GNUNET_TRANSPORT_Handle *handle,
546 const struct GNUNET_MessageHeader *hello,
547 GNUNET_SCHEDULER_Task cont, void *cls);
551 * Cancel the request to transport to offer the HELLO message
553 * @param ohh the GNUNET_TRANSPORT_OfferHelloHandle to cancel
556 GNUNET_TRANSPORT_offer_hello_cancel (struct GNUNET_TRANSPORT_OfferHelloHandle *ohh);
560 * Handle to cancel a pending address lookup.
562 struct GNUNET_TRANSPORT_AddressToStringContext;
566 * Convert a binary address into a human readable address.
568 * @param cfg configuration to use
569 * @param address address to convert (binary format)
570 * @param numeric should (IP) addresses be displayed in numeric form
571 * (otherwise do reverse DNS lookup)
572 * @param timeout how long is the lookup allowed to take at most
573 * @param aluc function to call with the results
574 * @param aluc_cls closure for aluc
575 * @return handle to cancel the operation, NULL on error
577 struct GNUNET_TRANSPORT_AddressToStringContext *
578 GNUNET_TRANSPORT_address_to_string (const struct GNUNET_CONFIGURATION_Handle
580 const struct GNUNET_HELLO_Address *address,
582 struct GNUNET_TIME_Relative timeout,
583 GNUNET_TRANSPORT_AddressToStringCallback
584 aluc, void *aluc_cls);
588 * Cancel request for address conversion.
590 * @param pic the context handle
593 GNUNET_TRANSPORT_address_to_string_cancel (struct
594 GNUNET_TRANSPORT_AddressToStringContext
598 * Convert a transport state to a human readable string.
600 * @param state the state
603 GNUNET_TRANSPORT_p2s (enum GNUNET_TRANSPORT_PeerState state);
607 * Check if a state is defined as connected
609 * @param state the state value
610 * @return GNUNET_YES or GNUNET_NO
613 GNUNET_TRANSPORT_is_connected (enum GNUNET_TRANSPORT_PeerState state);
617 * Return information about a specific peer or all peers currently known to
618 * transport service once or in monitoring mode. To obtain information about
619 * a specific peer, a peer identity can be passed. To obtain information about
620 * all peers currently known to transport service, NULL can be passed as peer
623 * For each peer, the callback is called with information about the address used
624 * to communicate with this peer, the state this peer is currently in and the
625 * the current timeout for this state.
627 * Upon completion, the 'GNUNET_TRANSPORT_PeerIterateCallback' is called one
628 * more time with 'NULL'. After this, the operation must no longer be
629 * explicitly canceled.
631 * The #GNUNET_TRANSPORT_monitor_peers_cancel call MUST not be called in the
634 * @param cfg configuration to use
635 * @param peer a specific peer identity to obtain information for,
637 * @param one_shot GNUNET_YES to return the current state and then end (with NULL+NULL),
638 * GNUNET_NO to monitor peers continuously
639 * @param timeout how long is the lookup allowed to take at most
640 * @param peer_callback function to call with the results
641 * @param peer_callback_cls closure for peer_address_callback
643 struct GNUNET_TRANSPORT_PeerMonitoringContext *
644 GNUNET_TRANSPORT_monitor_peers (const struct
645 GNUNET_CONFIGURATION_Handle *cfg,
646 const struct GNUNET_PeerIdentity *peer,
648 struct GNUNET_TIME_Relative timeout,
649 GNUNET_TRANSPORT_PeerIterateCallback peer_callback,
650 void *peer_callback_cls);
654 * Cancel request to monitor peers
656 * @param pic handle for the request to cancel
659 GNUNET_TRANSPORT_monitor_peers_cancel (struct GNUNET_TRANSPORT_PeerMonitoringContext *pic);
664 * Return information about pending address validation operations for a specific
667 * @param cfg configuration to use
668 * @param peer a specific peer identity to obtain validation entries for,
670 * @param one_shot GNUNET_YES to return all entries and then end (with NULL+NULL),
671 * GNUNET_NO to monitor validation entries continuously
672 * @param timeout how long is the lookup allowed to take at most
673 * @param validation_callback function to call with the results
674 * @param validation_callback_cls closure for peer_address_callback
676 struct GNUNET_TRANSPORT_ValidationMonitoringContext *
677 GNUNET_TRANSPORT_monitor_validation_entries (const struct
678 GNUNET_CONFIGURATION_Handle *cfg,
679 const struct GNUNET_PeerIdentity *peer,
681 struct GNUNET_TIME_Relative timeout,
682 GNUNET_TRANSPORT_ValidationIterateCallback validation_callback,
683 void *validation_callback_cls);
687 * Return information about all current pending validation operations
689 * @param vic handle for the request to cancel
692 GNUNET_TRANSPORT_monitor_validation_entries_cancel (struct GNUNET_TRANSPORT_ValidationMonitoringContext *vic);
697 * Handle for blacklisting peers.
699 struct GNUNET_TRANSPORT_Blacklist;
703 * Function that decides if a connection is acceptable or not.
706 * @param pid peer to approve or disapproave
707 * @return GNUNET_OK if the connection is allowed, GNUNET_SYSERR if not
709 typedef int (*GNUNET_TRANSPORT_BlacklistCallback) (void *cls,
711 GNUNET_PeerIdentity * pid);
715 * Install a blacklist callback. The service will be queried for all
716 * existing connections as well as any fresh connections to check if
717 * they are permitted. If the blacklisting callback is unregistered,
718 * all hosts that were denied in the past will automatically be
719 * whitelisted again. Cancelling the blacklist handle is also the
720 * only way to re-enable connections from peers that were previously
723 * @param cfg configuration to use
724 * @param cb callback to invoke to check if connections are allowed
725 * @param cb_cls closure for cb
726 * @return NULL on error, otherwise handle for cancellation
728 struct GNUNET_TRANSPORT_Blacklist *
729 GNUNET_TRANSPORT_blacklist (const struct GNUNET_CONFIGURATION_Handle *cfg,
730 GNUNET_TRANSPORT_BlacklistCallback cb,
735 * Abort the blacklist. Note that this function is the only way for
736 * removing a peer from the blacklist.
738 * @param br handle of the request that is to be cancelled
741 GNUNET_TRANSPORT_blacklist_cancel (struct GNUNET_TRANSPORT_Blacklist *br);
745 #if 0 /* keep Emacsens' auto-indent happy */
752 /* ifndef GNUNET_TRANSPORT_SERVICE_H */
754 /* end of gnunet_transport_service.h */