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3 (C) 2009-2014 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 #GNUNET_TRANSPORT_PS_NOT_CONNECTED.
50 * Then, there are two main paths. If we receive a CONNECT message, we
51 * first run a check against the blacklist (#GNUNET_TRANSPORT_PS_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 (#GNUNET_TRANSPORT_PS_CONNECT_RECV_ATS).
54 * If ATS makes a suggestion, we ALSO give that suggestion to the blacklist
55 * (#GNUNET_TRANSPORT_PS_CONNECT_RECV_BLACKLIST). Once the blacklist approves the
56 * address we got from ATS, we send our CONNECT_ACK and go to
57 * #GNUNET_TRANSPORT_PS_CONNECT_RECV_ACK. If we receive a SESSION_ACK, we go to
58 * #GNUNET_TRANSPORT_PS_CONNECTED (and notify everyone about the new connection).
59 * If the operation times out, we go to #GNUNET_TRANSPORT_PS_DISCONNECT.
61 * The other case is where we transmit a CONNECT message first. We
62 * start with #GNUNET_TRANSPORT_PS_INIT_ATS. If we get an address, we enter
63 * #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_CONNECT_SENT. Once we receive a CONNECT_ACK, we go to
66 * #GNUNET_TRANSPORT_PS_CONNECTED (and notify everyone about the new connection and send
67 * back a SESSION_ACK). If the operation times out, we go to
68 * #GNUNET_TRANSPORT_PS_DISCONNECT.
70 * If the session is in trouble (i.e. transport-level disconnect or
71 * timeout), we go to #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_RECONNECT_BLACKLIST to check the new
74 * address against the blacklist. If the blacklist approves, we enter
75 * #GNUNET_TRANSPORT_PS_RECONNECT_SENT and send a CONNECT message. If we receive a
76 * CONNECT_ACK, we go to #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_CONNECTED_SWITCHING_BLACKLIST to check the
83 * new address against the blacklist. If the blacklist approves, we
84 * go to #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_CONNECTED (and notify ATS that the given alternative
90 * address is "invalid").
92 * Once a session is in #GNUNET_TRANSPORT_PS_DISCONNECT, it is cleaned up and then goes
93 * to (#GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED). If we receive an explicit disconnect
94 * request, we can go from any state to #GNUNET_TRANSPORT_PS_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 #GNUNET_TRANSPORT_PS_CONNECTED (and reset 'send_connect_ack'
108 enum GNUNET_TRANSPORT_PeerState
111 * Fresh peer or completely disconnected
113 GNUNET_TRANSPORT_PS_NOT_CONNECTED = 0,
116 * Asked to initiate connection, trying to get address from ATS
118 GNUNET_TRANSPORT_PS_INIT_ATS,
121 * Asked to initiate connection, trying to get address approved
124 GNUNET_TRANSPORT_PS_INIT_BLACKLIST,
127 * Sent CONNECT message to other peer, waiting for CONNECT_ACK
129 GNUNET_TRANSPORT_PS_CONNECT_SENT,
132 * Received a CONNECT, do a blacklist check for inbound address
134 GNUNET_TRANSPORT_PS_CONNECT_RECV_BLACKLIST_INBOUND,
137 * Received a CONNECT, asking ATS about address suggestions.
139 GNUNET_TRANSPORT_PS_CONNECT_RECV_ATS,
142 * Received CONNECT from other peer, got an address, checking with blacklist.
144 GNUNET_TRANSPORT_PS_CONNECT_RECV_BLACKLIST,
147 * CONNECT request from other peer was SESSION_ACK'ed, waiting for
150 GNUNET_TRANSPORT_PS_CONNECT_RECV_ACK,
153 * Got our CONNECT_ACK/SESSION_ACK, connection is up.
155 GNUNET_TRANSPORT_PS_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_PS_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_PS_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_PS_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_PS_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_PS_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_PS_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_PS_DISCONNECT_FINISHED
211 * Current state of a validation process
213 enum GNUNET_TRANSPORT_ValidationState
218 * Used for final callback indicating operation done
220 GNUNET_TRANSPORT_VS_NONE,
223 * Fresh validation entry
225 * Entry was just created, no validation process was executed
227 GNUNET_TRANSPORT_VS_NEW,
230 * Updated validation entry
232 * This is an update for an existing validation entry
234 GNUNET_TRANSPORT_VS_UPDATE,
237 * Timeout for validation entry
239 * A timeout occured during the validation process
241 GNUNET_TRANSPORT_VS_TIMEOUT,
244 * Validation entry is removed
246 * The validation entry is getting removed due to a failed validation
248 GNUNET_TRANSPORT_VS_REMOVE
253 * Function called by the transport for each received message.
256 * @param peer (claimed) identity of the other peer
257 * @param message the message
258 * @param ats performance data
259 * @param ats_count number of entries in @a ats
262 (*GNUNET_TRANSPORT_ReceiveCallback) (void *cls,
263 const struct GNUNET_PeerIdentity *peer,
264 const struct GNUNET_MessageHeader *message);
268 * Opaque handle to the service.
270 struct GNUNET_TRANSPORT_Handle;
274 * Function called to notify transport users that another
275 * peer connected to us.
278 * @param peer the peer that connected
279 * @param ats performance data
280 * @param ats_count number of entries in @a ats (excluding 0-termination)
283 (*GNUNET_TRANSPORT_NotifyConnect) (void *cls,
284 const struct GNUNET_PeerIdentity *peer);
287 * Function called to notify transport users that another
288 * peer disconnected from us.
291 * @param peer the peer that disconnected
294 (*GNUNET_TRANSPORT_NotifyDisconnect) (void *cls,
295 const struct GNUNET_PeerIdentity *peer);
299 * Function to call with result of the try connect request.
303 * @param result #GNUNET_OK if message was transmitted to transport service
304 * #GNUNET_SYSERR if message was not transmitted to transport service
307 (*GNUNET_TRANSPORT_TryConnectCallback) (void *cls,
312 * Function to call with a textual representation of an address.
313 * This function will be called several times with different possible
314 * textual representations, and a last time with NULL to signal the end
318 * @param address NULL on error or end of iteration,
319 * otherwise 0-terminated printable UTF-8 string
322 (*GNUNET_TRANSPORT_AddressToStringCallback) (void *cls,
323 const char *address);
327 * Function to call with information about a peer
329 * If one_shot was set to #GNUNET_YES to iterate over all peers once,
330 * a final call with NULL for peer and address will follow when done.
331 * In this case state and timeout do not contain valid values.
333 * The #GNUNET_TRANSPORT_monitor_peers_cancel call MUST not be called from
334 * within this function!
338 * @param peer peer this update is about,
339 * NULL if this is the final last callback for a iteration operation
340 * @param address address, NULL for disconnect notification in monitor mode
341 * @param state current state this peer is in
342 * @param state_timeout timeout for the current state of the peer
345 (*GNUNET_TRANSPORT_PeerIterateCallback) (void *cls,
346 const struct GNUNET_PeerIdentity *peer,
347 const struct GNUNET_HELLO_Address *address,
348 enum GNUNET_TRANSPORT_PeerState state,
349 struct GNUNET_TIME_Absolute state_timeout);
353 * Function to call with validation information about a peer
355 * This function is called by the transport validation monitoring api to
356 * indicate a change to a validation entry. The information included represent
357 * the current state of the validation entry,
359 * If the monitoring was called with one_shot=GNUNET_YES, a final callback
360 * with peer==NULL and address==NULL is executed.
363 * @param peer peer this update is about,
364 * NULL if this is the final last callback for a iteration operation
365 * @param address address,
366 * NULL for disconnect notification in monitor mode
367 * @param valid_until when does this address expire
368 * @param next_validation time of the next validation operation
372 (*GNUNET_TRANSPORT_ValidationIterateCallback) (void *cls,
373 const struct GNUNET_PeerIdentity *peer,
374 const struct GNUNET_HELLO_Address *address,
375 struct GNUNET_TIME_Absolute last_validation,
376 struct GNUNET_TIME_Absolute valid_until,
377 struct GNUNET_TIME_Absolute next_validation,
378 enum GNUNET_TRANSPORT_ValidationState state);
382 * Connect to the transport service. Note that the connection may
383 * complete (or fail) asynchronously.
385 * @param cfg configuration to use
386 * @param self our own identity (API should check that it matches
387 * the identity found by transport), or NULL (no check)
388 * @param cls closure for the callbacks
389 * @param rec receive function to call, or NULL
390 * @param nc function to call on connect events, or NULL
391 * @param nd function to call on disconnect events, or NULL
392 * @return NULL on error
394 struct GNUNET_TRANSPORT_Handle *
395 GNUNET_TRANSPORT_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
396 const struct GNUNET_PeerIdentity *self,
398 GNUNET_TRANSPORT_ReceiveCallback rec,
399 GNUNET_TRANSPORT_NotifyConnect nc,
400 GNUNET_TRANSPORT_NotifyDisconnect nd);
404 * Disconnect from the transport service.
406 * @param handle handle returned from connect
409 GNUNET_TRANSPORT_disconnect (struct GNUNET_TRANSPORT_Handle *handle);
413 * Opaque handle for a transmission-ready request.
415 struct GNUNET_TRANSPORT_TryConnectHandle;
419 * Ask the transport service to establish a connection to
422 * @param handle connection to transport service
423 * @param target who we should try to connect to
424 * @param cb callback to be called when request was transmitted to transport
426 * @param cb_cls closure for the callback @a cb
427 * @return a `struct GNUNET_TRANSPORT_TryConnectHandle` handle or
428 * NULL on failure (@a cb will not be called)
430 struct GNUNET_TRANSPORT_TryConnectHandle *
431 GNUNET_TRANSPORT_try_connect (struct GNUNET_TRANSPORT_Handle *handle,
432 const struct GNUNET_PeerIdentity *target,
433 GNUNET_TRANSPORT_TryConnectCallback cb,
438 * Cancel the request to transport to try a connect
439 * Callback will not be called
441 * @param tch GNUNET_TRANSPORT_TryConnectHandle handle to cancel
444 GNUNET_TRANSPORT_try_connect_cancel (struct GNUNET_TRANSPORT_TryConnectHandle *tch);
448 * Opaque handle for a transmission-ready request.
450 struct GNUNET_TRANSPORT_TransmitHandle;
454 * Check if we could queue a message of the given size for
455 * transmission. The transport service will take both its internal
456 * buffers and bandwidth limits imposed by the other peer into
457 * consideration when answering this query.
459 * @param handle connection to transport service
460 * @param target who should receive the message
461 * @param size how big is the message we want to transmit?
462 * @param priority how important is the message? @deprecated - remove?
463 * @param timeout after how long should we give up (and call
464 * notify with buf NULL and size 0)?
465 * @param notify function to call when we are ready to
466 * send such a message
467 * @param notify_cls closure for @a notify
468 * @return NULL if someone else is already waiting to be notified
469 * non-NULL if the notify callback was queued (can be used to cancel
470 * using GNUNET_TRANSPORT_notify_transmit_ready_cancel)
472 struct GNUNET_TRANSPORT_TransmitHandle *
473 GNUNET_TRANSPORT_notify_transmit_ready (struct GNUNET_TRANSPORT_Handle *handle,
474 const struct GNUNET_PeerIdentity *target,
477 struct GNUNET_TIME_Relative timeout,
478 GNUNET_CONNECTION_TransmitReadyNotify notify,
483 * Cancel the specified transmission-ready notification.
485 * @param th handle of the transmission notification request to cancel
488 GNUNET_TRANSPORT_notify_transmit_ready_cancel (struct GNUNET_TRANSPORT_TransmitHandle *th);
492 * Function called whenever there is an update to the
493 * HELLO of this peer.
496 * @param hello our updated HELLO
499 (*GNUNET_TRANSPORT_HelloUpdateCallback) (void *cls,
500 const struct GNUNET_MessageHeader *hello);
504 * Handle to cancel a #GNUNET_TRANSPORT_get_hello() operation.
506 struct GNUNET_TRANSPORT_GetHelloHandle;
510 * Checks if a given peer is connected to us
512 * @param handle connection to transport service
513 * @param peer the peer to check
514 * @return #GNUNET_YES (connected) or #GNUNET_NO (disconnected)
517 GNUNET_TRANSPORT_check_peer_connected (struct GNUNET_TRANSPORT_Handle *handle,
518 const struct GNUNET_PeerIdentity *peer);
522 * Set transport metrics for a peer and a direction
524 * @param handle transport handle
525 * @param peer the peer to set the metric for
526 * @param inbound set inbound direction (#GNUNET_YES or #GNUNET_NO)
527 * @param outbound set outbound direction (#GNUNET_YES or #GNUNET_NO)
528 * @param ats the metric as ATS information
529 * @param ats_count the number of metrics
531 * Supported ATS values:
532 * #GNUNET_ATS_QUALITY_NET_DELAY (value in ms)
533 * #GNUNET_ATS_QUALITY_NET_DISTANCE (value in count(hops))
536 * To enforce a delay of 10 ms for peer p1 in sending direction use:
538 * struct GNUNET_ATS_Information ats;
539 * ats.type = ntohl (GNUNET_ATS_QUALITY_NET_DELAY);
540 * ats.value = ntohl (10);
541 * GNUNET_TRANSPORT_set_traffic_metric (th, p1, TM_SEND, &ats, 1);
544 * Delay restrictions in receiving direction will be enforced with
548 GNUNET_TRANSPORT_set_traffic_metric (struct GNUNET_TRANSPORT_Handle *handle,
549 const struct GNUNET_PeerIdentity *peer,
552 const struct GNUNET_ATS_Information *ats,
557 * Obtain updates on changes to the HELLO message for this peer. The callback
558 * given in this function is never called synchronously.
560 * @param handle connection to transport service
561 * @param rec function to call with the HELLO
562 * @param rec_cls closure for @a rec
563 * @return handle to cancel the operation
565 struct GNUNET_TRANSPORT_GetHelloHandle *
566 GNUNET_TRANSPORT_get_hello (struct GNUNET_TRANSPORT_Handle *handle,
567 GNUNET_TRANSPORT_HelloUpdateCallback rec,
572 * Stop receiving updates about changes to our HELLO message.
574 * @param ghh handle to cancel
577 GNUNET_TRANSPORT_get_hello_cancel (struct GNUNET_TRANSPORT_GetHelloHandle *ghh);
581 * Offer the transport service the HELLO of another peer. Note that
582 * the transport service may just ignore this message if the HELLO is
583 * malformed or useless due to our local configuration.
585 * @param handle connection to transport service
586 * @param hello the hello message
587 * @param cont continuation to call when HELLO has been sent,
588 * tc reason #GNUNET_SCHEDULER_REASON_TIMEOUT for fail
589 * tc reasong #GNUNET_SCHEDULER_REASON_READ_READY for success
590 * @param cls closure for continuation
591 * @return a GNUNET_TRANSPORT_OfferHelloHandle handle or NULL on failure,
592 * in case of failure cont will not be called
595 struct GNUNET_TRANSPORT_OfferHelloHandle *
596 GNUNET_TRANSPORT_offer_hello (struct GNUNET_TRANSPORT_Handle *handle,
597 const struct GNUNET_MessageHeader *hello,
598 GNUNET_SCHEDULER_Task cont, void *cls);
602 * Cancel the request to transport to offer the HELLO message
604 * @param ohh the `struct GNUNET_TRANSPORT_OfferHelloHandle` to cancel
607 GNUNET_TRANSPORT_offer_hello_cancel (struct GNUNET_TRANSPORT_OfferHelloHandle *ohh);
611 * Handle to cancel a pending address lookup.
613 struct GNUNET_TRANSPORT_AddressToStringContext;
617 * Convert a binary address into a human readable address.
619 * @param cfg configuration to use
620 * @param address address to convert (binary format)
621 * @param numeric should (IP) addresses be displayed in numeric form
622 * (otherwise do reverse DNS lookup)
623 * @param timeout how long is the lookup allowed to take at most
624 * @param aluc function to call with the results
625 * @param aluc_cls closure for @a aluc
626 * @return handle to cancel the operation, NULL on error
628 struct GNUNET_TRANSPORT_AddressToStringContext *
629 GNUNET_TRANSPORT_address_to_string (const struct GNUNET_CONFIGURATION_Handle *cfg,
630 const struct GNUNET_HELLO_Address *address,
632 struct GNUNET_TIME_Relative timeout,
633 GNUNET_TRANSPORT_AddressToStringCallback aluc,
638 * Cancel request for address conversion.
640 * @param pic the context handle
643 GNUNET_TRANSPORT_address_to_string_cancel (struct GNUNET_TRANSPORT_AddressToStringContext *pic);
647 * Convert a transport state to a human readable string.
649 * @param state the state
652 GNUNET_TRANSPORT_ps2s (enum GNUNET_TRANSPORT_PeerState state);
656 * Check if a state is defined as connected
658 * @param state the state value
659 * @return #GNUNET_YES or #GNUNET_NO
662 GNUNET_TRANSPORT_is_connected (enum GNUNET_TRANSPORT_PeerState state);
666 * Convert validation state to human-readable string.
668 * @param state the state value
669 * @return corresponding string
672 GNUNET_TRANSPORT_vs2s (enum GNUNET_TRANSPORT_ValidationState state);
676 * Return information about a specific peer or all peers currently known to
677 * transport service once or in monitoring mode. To obtain information about
678 * a specific peer, a peer identity can be passed. To obtain information about
679 * all peers currently known to transport service, NULL can be passed as peer
682 * For each peer, the callback is called with information about the address used
683 * to communicate with this peer, the state this peer is currently in and the
684 * the current timeout for this state.
686 * Upon completion, the 'GNUNET_TRANSPORT_PeerIterateCallback' is called one
687 * more time with 'NULL'. After this, the operation must no longer be
688 * explicitly canceled.
690 * The #GNUNET_TRANSPORT_monitor_peers_cancel call MUST not be called in the
693 * @param cfg configuration to use
694 * @param peer a specific peer identity to obtain information for,
696 * @param one_shot #GNUNET_YES to return the current state and then end (with NULL+NULL),
697 * #GNUNET_NO to monitor peers continuously
698 * @param timeout how long is the lookup allowed to take at most
699 * @param peer_callback function to call with the results
700 * @param peer_callback_cls closure for @a peer_callback
702 struct GNUNET_TRANSPORT_PeerMonitoringContext *
703 GNUNET_TRANSPORT_monitor_peers (const struct GNUNET_CONFIGURATION_Handle *cfg,
704 const struct GNUNET_PeerIdentity *peer,
706 struct GNUNET_TIME_Relative timeout,
707 GNUNET_TRANSPORT_PeerIterateCallback peer_callback,
708 void *peer_callback_cls);
712 * Cancel request to monitor peers
714 * @param pic handle for the request to cancel
717 GNUNET_TRANSPORT_monitor_peers_cancel (struct GNUNET_TRANSPORT_PeerMonitoringContext *pic);
721 * Return information about pending address validation operations for a specific
724 * @param cfg configuration to use
725 * @param peer a specific peer identity to obtain validation entries for,
727 * @param one_shot #GNUNET_YES to return all entries and then end (with NULL+NULL),
728 * #GNUNET_NO to monitor validation entries continuously
729 * @param timeout how long is the lookup allowed to take at most
730 * @param validation_callback function to call with the results
731 * @param validation_callback_cls closure for @a validation_callback
733 struct GNUNET_TRANSPORT_ValidationMonitoringContext *
734 GNUNET_TRANSPORT_monitor_validation_entries (const struct GNUNET_CONFIGURATION_Handle *cfg,
735 const struct GNUNET_PeerIdentity *peer,
737 struct GNUNET_TIME_Relative timeout,
738 GNUNET_TRANSPORT_ValidationIterateCallback validation_callback,
739 void *validation_callback_cls);
743 * Return information about all current pending validation operations
745 * @param vic handle for the request to cancel
748 GNUNET_TRANSPORT_monitor_validation_entries_cancel (struct GNUNET_TRANSPORT_ValidationMonitoringContext *vic);
752 * Handle for blacklisting peers.
754 struct GNUNET_TRANSPORT_Blacklist;
758 * Function that decides if a connection is acceptable or not.
761 * @param pid peer to approve or disapproave
762 * @return #GNUNET_OK if the connection is allowed, #GNUNET_SYSERR if not
765 (*GNUNET_TRANSPORT_BlacklistCallback) (void *cls,
767 GNUNET_PeerIdentity * pid);
771 * Install a blacklist callback. The service will be queried for all
772 * existing connections as well as any fresh connections to check if
773 * they are permitted. If the blacklisting callback is unregistered,
774 * all hosts that were denied in the past will automatically be
775 * whitelisted again. Cancelling the blacklist handle is also the
776 * only way to re-enable connections from peers that were previously
779 * @param cfg configuration to use
780 * @param cb callback to invoke to check if connections are allowed
781 * @param cb_cls closure for @a cb
782 * @return NULL on error, otherwise handle for cancellation
784 struct GNUNET_TRANSPORT_Blacklist *
785 GNUNET_TRANSPORT_blacklist (const struct GNUNET_CONFIGURATION_Handle *cfg,
786 GNUNET_TRANSPORT_BlacklistCallback cb,
791 * Abort the blacklist. Note that this function is the only way for
792 * removing a peer from the blacklist.
794 * @param br handle of the request that is to be cancelled
797 GNUNET_TRANSPORT_blacklist_cancel (struct GNUNET_TRANSPORT_Blacklist *br);
801 #if 0 /* keep Emacsens' auto-indent happy */
808 /* ifndef GNUNET_TRANSPORT_SERVICE_H */
810 /* end of gnunet_transport_service.h */