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3 (C) 2012, 2013 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_multicast_service.h
23 * @brief multicast service; establish tunnels to distant peers
24 * @author Christian Grothoff
25 * @author Gabor X Toth
28 #ifndef GNUNET_MULTICAST_SERVICE_H
29 #define GNUNET_MULTICAST_SERVICE_H
34 #if 0 /* keep Emacsens' auto-indent happy */
39 #include "gnunet_util_lib.h"
40 #include "gnunet_transport_service.h"
43 * Version number of GNUnet-multicast API.
45 #define GNUNET_MULTICAST_VERSION 0x00000000
48 * Maximum size of a multicast message fragment.
50 #define GNUNET_MULTICAST_FRAGMENT_MAX_SIZE 63 * 1024
53 * Opaque handle for a multicast group member.
55 struct GNUNET_MULTICAST_Member;
58 * Handle for the origin of a multicast group.
60 struct GNUNET_MULTICAST_Origin;
63 enum GNUNET_MULTICAST_MessageFlags
66 * First fragment of a message.
68 GNUNET_MULTICAST_MESSAGE_FIRST_FRAGMENT = 1 << 0,
71 * Last fragment of a message.
73 GNUNET_MULTICAST_MESSAGE_LAST_FRAGMENT = 1 << 1,
76 * OR'ed flags if message is not fragmented.
78 GNUNET_MULTICAST_MESSAGE_NOT_FRAGMENTED
79 = GNUNET_MULTICAST_MESSAGE_FIRST_FRAGMENT
80 | GNUNET_MULTICAST_MESSAGE_LAST_FRAGMENT
84 GNUNET_NETWORK_STRUCT_BEGIN
87 * Header of a multicast message fragment.
89 * This format is public as the replay mechanism must replay message fragments using the
90 * same format. This is needed as we want to integrity-check message fragments within
91 * the multicast layer to avoid multicasting mal-formed messages.
93 struct GNUNET_MULTICAST_MessageHeader
97 * Header for all multicast message fragments from the origin.
99 struct GNUNET_MessageHeader header;
102 * Number of hops this message fragment has taken since the origin.
104 * Helpful to determine shortest paths to the origin among honest peers for
105 * unicast requests from members. Updated at each hop and thus not signed and
108 uint32_t hop_counter GNUNET_PACKED;
111 * ECC signature of the message fragment.
113 * Signature must match the public key of the multicast group.
115 struct GNUNET_CRYPTO_EccSignature signature;
118 * Purpose for the signature and size of the signed data.
120 struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
123 * Number of the message fragment, monotonically increasing.
125 uint64_t fragment_id GNUNET_PACKED;
128 * Byte offset of this @e fragment of the @e message.
130 uint64_t fragment_offset GNUNET_PACKED;
133 * Number of the message this fragment belongs to.
135 * Set in GNUNET_MULTICAST_origin_to_all().
137 uint64_t message_id GNUNET_PACKED;
140 * Counter that monotonically increases whenever a member parts the group.
142 * Set in GNUNET_MULTICAST_origin_to_all().
144 * It has significance in case of replay requests: when a member has missed
145 * messages and gets a replay request: in this case if the @a group_generation
146 * is still the same before and after the missed messages, it means that no
147 * @e join or @e part operations happened during the missed messages.
149 uint64_t group_generation GNUNET_PACKED;
152 * Flags for this message fragment.
154 uint32_t flags GNUNET_PACKED;
156 /* Followed by message body. */
159 GNUNET_NETWORK_STRUCT_END
163 * Handle that identifies a join request.
165 * Used to match calls to #GNUNET_MULTICAST_JoinCallback to the
166 * corresponding calls to #GNUNET_MULTICAST_join_decision().
168 struct GNUNET_MULTICAST_JoinHandle;
172 * Function to call with the decision made for a join request.
174 * Must be called once and only once in response to an invocation of the
175 * #GNUNET_MULTICAST_JoinCallback.
177 * @param jh Join request handle.
178 * @param is_admitted #GNUNET_YES if joining is approved,
179 * #GNUNET_NO if it is disapproved
180 * @param relay_count Number of relays given.
181 * @param relays Array of suggested peers that might be useful relays to use
182 * when joining the multicast group (essentially a list of peers that
183 * are already part of the multicast group and might thus be willing
184 * to help with routing). If empty, only this local peer (which must
185 * be the multicast origin) is a good candidate for building the
186 * multicast tree. Note that it is unnecessary to specify our own
187 * peer identity in this array.
188 * @param join_response Message to send in response to the joining peer;
189 * can also be used to redirect the peer to a different group at the
190 * application layer; this response is to be transmitted to the
191 * peer that issued the request even if admission is denied.
193 struct GNUNET_MULTICAST_ReplayHandle *
194 GNUNET_MULTICAST_join_decision (struct GNUNET_MULTICAST_JoinHandle *jh,
196 unsigned int relay_count,
197 const struct GNUNET_PeerIdentity *relays,
198 const struct GNUNET_MessageHeader *join_response);
202 * Method called whenever another peer wants to join the multicast group.
204 * Implementations of this function must call GNUNET_MULTICAST_join_decision()
207 * @param cls Closure.
208 * @param peer Identity of the member that wants to join.
209 * @param join_req Application-dependent join message from the new member
210 * (might, for example, contain a user,
211 * bind user identity/pseudonym to peer identity, application-level
212 * message to origin, etc.).
213 * @param jh Join handle to pass to GNUNET_MULTICAST_join_decison().
216 (*GNUNET_MULTICAST_JoinCallback) (void *cls,
217 const struct GNUNET_CRYPTO_EccPublicSignKey *member_key,
218 const struct GNUNET_MessageHeader *join_req,
219 struct GNUNET_MULTICAST_JoinHandle *jh);
223 * Handle to pass back for the answer of a membership test.
225 struct GNUNET_MULTICAST_MembershipTestHandle;
229 * Call informing multicast about the decision taken for a membership test.
231 * @param mth Handle that was given for the query.
232 * @param result #GNUNET_YES if peer was a member, #GNUNET_NO if peer was not a member,
233 * #GNUNET_SYSERR if we cannot answer the membership test.
236 GNUNET_MULTICAST_membership_test_result (struct GNUNET_MULTICAST_MembershipTestHandle *mth,
241 * Method called to test if a member was in the group at a particular time.
243 * It is called when a replay request is received to determine if the requested
244 * message can be replayed.
246 * @param cls Closure.
247 * @param member_key Identity of the member that we want to test.
248 * @param message_id Message ID for which to perform the test.
249 * @param group_generation Group generation of the message. It has relevance if
250 * the message consists of multiple fragments with different group
252 * @param mth Handle to give to GNUNET_MULTICAST_membership_test_answer().
255 (*GNUNET_MULTICAST_MembershipTestCallback) (void *cls,
256 const struct GNUNET_CRYPTO_EccPublicSignKey *member_key,
258 uint64_t group_generation,
259 struct GNUNET_MULTICAST_MembershipTestHandle *mth);
263 * Function called whenever a group member has transmitted a request
264 * to the origin (other than joining or leaving).
266 * FIXME: need to distinguish between origin cancelling a message (some fragments
267 * were sent, then the rest 'discarded') and the case where we got disconnected;
268 * right now, both would mean 'msg' is NULL, but they could be quite different...
269 * So the semantics from the receiver side of
270 * GNUNET_MULTICAST_member_to_origin_cancel() are not clear here. Maybe we
271 * should do something with the flags in this case?
273 * @param cls Closure (set from GNUNET_MULTICAST_origin_start).
274 * @param sender Identity of the sender.
275 * @param req Request to the origin.
276 * @param flags Flags for the request.
279 (*GNUNET_MULTICAST_RequestCallback) (void *cls,
280 const struct GNUNET_CRYPTO_EccPublicSignKey *member_key,
281 const struct GNUNET_MessageHeader *req,
282 enum GNUNET_MULTICAST_MessageFlags flags);
286 * Function called whenever a group member is receiving a message fragment from
289 * If admission to the group is denied, this function is called once with the
290 * response of the @e origin (as given to GNUNET_MULTICAST_join_decision()) and
291 * then a second time with NULL to indicate that the connection failed for good.
293 * FIXME: need to distinguish between origin cancelling a message (some fragments
294 * were sent, then the rest 'discarded') and the case where we got disconnected;
295 * right now, both would mean 'msg' is NULL, but they could be quite different...
296 * So the semantics from the receiver side of
297 * GNUNET_MULTICAST_origin_to_all_cancel() are not clear here.
299 * @param cls Closure (set from GNUNET_MULTICAST_member_join())
300 * @param msg Message from the origin, NULL if the origin shut down
301 * (or we were kicked out, and we should thus call
302 * GNUNET_MULTICAST_member_part() next)
305 (*GNUNET_MULTICAST_MessageCallback) (void *cls,
306 const struct GNUNET_MessageHeader *msg);
310 * Function called with the result of an asynchronous operation.
312 * @see GNUNET_MULTICAST_replay_fragment()
314 * @param result Result of the operation.
317 (*GNUNET_MULTICAST_ResultCallback) (void *cls,
322 * Opaque handle to a replay request from the multicast service.
324 struct GNUNET_MULTICAST_ReplayHandle;
328 * Functions with this signature are called whenever the multicast service needs
329 * a message fragment to be replayed by fragment_id.
331 * Implementations of this function MUST call GNUNET_MULTICAST_replay() ONCE
332 * (with a message or an error); however, if the origin is destroyed or the
333 * group is left, the replay handle must no longer be used.
335 * @param cls Closure (set from GNUNET_MULTICAST_origin_start()
336 * or GNUNET_MULTICAST_member_join()).
337 * @param member_key The member requesting replay.
338 * @param fragment_id Which message fragment should be replayed.
339 * @param flags Flags for the replay.
340 * @param rh Handle to pass to message transmit function.
343 (*GNUNET_MULTICAST_ReplayFragmentCallback) (void *cls,
344 const struct GNUNET_CRYPTO_EccPublicSignKey *member_key,
345 uint64_t fragment_id,
347 struct GNUNET_MULTICAST_ReplayHandle *rh);
350 * Functions with this signature are called whenever the multicast service needs
351 * a message fragment to be replayed by message_id and fragment_offset.
353 * Implementations of this function MUST call GNUNET_MULTICAST_replay() ONCE
354 * (with a message or an error); however, if the origin is destroyed or the
355 * group is left, the replay handle must no longer be used.
357 * @param cls Closure (set from GNUNET_MULTICAST_origin_start()
358 * or GNUNET_MULTICAST_member_join()).
359 * @param member_key The member requesting replay.
360 * @param message_id Which message should be replayed.
361 * @param fragment_offset Offset of the fragment within of @a message_id to be replayed.
362 * @param flags Flags for the replay.
363 * @param rh Handle to pass to message transmit function.
366 (*GNUNET_MULTICAST_ReplayMessageCallback) (void *cls,
367 const struct GNUNET_CRYPTO_EccPublicSignKey *member_key,
369 uint64_t fragment_offset,
371 struct GNUNET_MULTICAST_ReplayHandle *rh);
375 * Possible error codes during replay.
377 enum GNUNET_MULTICAST_ReplayErrorCode
381 * Everything is fine.
383 GNUNET_MULTICAST_REC_OK = 0,
386 * Message fragment not found in the message store.
388 * Either discarded if it is too old, or not arrived yet if this member has
389 * missed some messages.
391 GNUNET_MULTICAST_REC_NOT_FOUND = 1,
394 * Fragment ID counter was larger than the highest counter this
395 * replay function has ever encountered; thus it is likely the
396 * origin never sent it and we're at the HEAD of the multicast
397 * stream as far as this node is concerned.
401 GNUNET_MULTICAST_REC_PAST_HEAD = 2,
404 * Access is denied to the requested fragment, membership test did not pass.
406 GNUNET_MULTICAST_REC_ACCESS_DENIED = 3,
409 * Internal error (i.e. database error). Try some other peer.
411 GNUNET_MULTICAST_REC_INTERNAL_ERROR = 4
417 * Replay a message fragment for the multicast group.
419 * @param rh Replay handle identifying which replay operation was requested.
420 * @param msg Replayed message fragment, NULL if unknown/error.
421 * @param ec Error code.
424 GNUNET_MULTICAST_replay_response (struct GNUNET_MULTICAST_ReplayHandle *rh,
425 const struct GNUNET_MessageHeader *msg,
426 enum GNUNET_MULTICAST_ReplayErrorCode ec);
430 * Indicate the end of the replay session.
432 * Invalidates the replay handle.
434 * @param rh Replay session to end.
437 GNUNET_MULTICAST_replay_response_end (struct GNUNET_MULTICAST_ReplayHandle *rh);
441 * Function called to provide data for a transmission for a replay.
443 * @see GNUNET_MULTICAST_replay2()
446 (*GNUNET_MULTICAST_ReplayTransmitNotify) (void *cls,
452 * Replay a message for the multicast group.
454 * @param rh Replay handle identifying which replay operation was requested.
455 * @param notify Function to call to get the message.
456 * @param notify_cls Closure for @a notify.
459 GNUNET_MULTICAST_replay_response2 (struct GNUNET_MULTICAST_ReplayHandle *rh,
460 GNUNET_MULTICAST_ReplayTransmitNotify notify,
465 * Start a multicast group.
467 * Will advertise the origin in the P2P overlay network under the respective
468 * public key so that other peer can find this peer to join it. Peers that
469 * issue GNUNET_MULTICAST_member_join() can then transmit a join request to
470 * either an existing group member or to the origin. If the joining is
471 * approved, the member is cleared for @e replay and will begin to receive
472 * messages transmitted to the group. If joining is disapproved, the failed
473 * candidate will be given a response. Members in the group can send messages
474 * to the origin (one at a time).
476 * @param cfg Configuration to use.
477 * @param priv_key ECC key that will be used to sign messages for this
478 * multicast session; public key is used to identify the multicast group;
479 * @param next_fragment_id Next fragment ID to continue counting fragments from
480 * when restarting the origin. 1 for a new group.
481 * @param join_cb Function called to approve / disapprove joining of a peer.
482 * @param mem_test_cb Function multicast can use to test group membership.
483 * @param replay_frag_cb Function that can be called to replay a message fragment.
484 * @param replay_msg_cb Function that can be called to replay a message.
485 * @param request_cb Function called with message fragments from group members.
486 * @param message_cb Function called with the message fragments sent to the
487 * network by GNUNET_MULTICAST_origin_to_all(). These message fragments
488 * should be stored for answering replay requests later.
489 * @param cls Closure for the various callbacks that follow.
490 * @return Handle for the origin, NULL on error.
492 struct GNUNET_MULTICAST_Origin *
493 GNUNET_MULTICAST_origin_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
494 const struct GNUNET_CRYPTO_EccPrivateKey *priv_key,
495 uint64_t next_fragment_id,
496 GNUNET_MULTICAST_JoinCallback join_cb,
497 GNUNET_MULTICAST_MembershipTestCallback mem_test_cb,
498 GNUNET_MULTICAST_ReplayFragmentCallback replay_frag_cb,
499 GNUNET_MULTICAST_ReplayMessageCallback replay_msg_cb,
500 GNUNET_MULTICAST_RequestCallback request_cb,
501 GNUNET_MULTICAST_MessageCallback message_cb,
505 * Function called to provide data for a transmission from the origin to all
508 * Note that returning #GNUNET_OK or #GNUNET_SYSERR (but not #GNUNET_NO)
509 * invalidates the respective transmission handle.
511 * @param cls Closure.
512 * @param[in,out] data_size Initially set to the number of bytes available in
513 * @a data, should be set to the number of bytes written to data.
514 * @param[out] data Where to write the body of the message to give to the
515 * method. The function must copy at most @a data_size bytes to @a data.
516 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
517 * #GNUNET_NO on success, if more data is to be transmitted later.
518 * Should be used if @a data_size was not big enough to take all the
519 * data. If 0 is returned in @a data_size the transmission is paused,
520 * and can be resumed with GNUNET_MULTICAST_origin_to_all_resume().
521 * #GNUNET_YES if this completes the transmission (all data supplied)
524 (*GNUNET_MULTICAST_OriginTransmitNotify) (void *cls,
530 * Handle for a request to send a message to all multicast group members
533 struct GNUNET_MULTICAST_OriginMessageHandle;
537 * Send a message to the multicast group.
539 * @param origin Handle to the multicast group.
540 * @param message_id Application layer ID for the message. Opaque to multicast.
541 * @param group_generation Group generation of the message. Documented in
542 * GNUNET_MULTICAST_MessageHeader.
543 * @param notify Function to call to get the message.
544 * @param notify_cls Closure for @a notify.
545 * @return NULL on error (i.e. request already pending).
547 struct GNUNET_MULTICAST_OriginMessageHandle *
548 GNUNET_MULTICAST_origin_to_all (struct GNUNET_MULTICAST_Origin *origin,
550 uint64_t group_generation,
551 GNUNET_MULTICAST_OriginTransmitNotify notify,
557 * Resume message transmission to multicast group.
559 * @param mh Request to cancel.
562 GNUNET_MULTICAST_origin_to_all_resume (struct GNUNET_MULTICAST_OriginMessageHandle *mh);
566 * Cancel request for message transmission to multicast group.
568 * @param mh Request to cancel.
571 GNUNET_MULTICAST_origin_to_all_cancel (struct GNUNET_MULTICAST_OriginMessageHandle *mh);
575 * Stop a multicast group.
577 * @param origin Multicast group to stop.
580 GNUNET_MULTICAST_origin_stop (struct GNUNET_MULTICAST_Origin *origin);
584 * Join a multicast group.
586 * The entity joining is always the local peer. Further information about the
587 * candidate can be provided in the @a join_request message. If the join fails, the
588 * @a message_cb is invoked with a (failure) response and then with NULL. If
589 * the join succeeds, outstanding (state) messages and ongoing multicast
590 * messages will be given to the @a message_cb until the member decides to part
591 * the group. The @a mem_test_cb and @a replay_cb functions may be called at
592 * anytime by the multicast service to support relaying messages to other
593 * members of the group.
595 * @param cfg Configuration to use.
596 * @param group_key ECC public key that identifies the group to join.
597 * @param member_key ECC key that identifies the member and used to sign
598 * requests sent to the origin.
599 * @param origin Peer ID of the origin to send unicast requsets to. If NULL,
600 * unicast requests are sent back via multiple hops on the reverse path
601 * of multicast messages.
602 * @param relay_count Number of peers in the @a relays array.
603 * @param relays Peer identities of members of the group, which serve as relays
604 * and can be used to join the group at. and send the @a join_request to.
605 * If empty, the @a join_request is sent directly to the @a origin.
606 * @param join_request Application-dependent join request to be passed to the peer
607 * @a relay (might, for example, contain a user, bind user
608 * identity/pseudonym to peer identity, application-level message to
610 * @param join_cb Function called to approve / disapprove joining of a peer.
611 * @param mem_test_cb Function multicast can use to test group membership.
612 * @param replay_frag_cb Function that can be called to replay message fragments
613 * this peer already knows from this group. NULL if this
614 * client is unable to support replay.
615 * @param replay_msg_cb Function that can be called to replay message fragments
616 * this peer already knows from this group. NULL if this
617 * client is unable to support replay.
618 * @param message_cb Function to be called for all message fragments we
619 * receive from the group, excluding those our @a replay_cb
621 * @param cls Closure for callbacks.
622 * @return Handle for the member, NULL on error.
624 struct GNUNET_MULTICAST_Member *
625 GNUNET_MULTICAST_member_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
626 const struct GNUNET_CRYPTO_EccPublicSignKey *group_key,
627 const struct GNUNET_CRYPTO_EccPrivateKey *member_key,
628 const struct GNUNET_PeerIdentity *origin,
629 uint32_t relay_count,
630 const struct GNUNET_PeerIdentity *relays,
631 const struct GNUNET_MessageHeader *join_request,
632 GNUNET_MULTICAST_JoinCallback join_cb,
633 GNUNET_MULTICAST_MembershipTestCallback mem_test_cb,
634 GNUNET_MULTICAST_ReplayFragmentCallback replay_frag_cb,
635 GNUNET_MULTICAST_ReplayMessageCallback replay_msg_cb,
636 GNUNET_MULTICAST_MessageCallback message_cb,
640 * Handle for a replay request.
642 struct GNUNET_MULTICAST_MemberReplayHandle;
646 * Request a fragment to be replayed by fragment ID.
648 * Useful if messages below the @e max_known_fragment_id given when joining are
649 * needed and not known to the client.
651 * @param member Membership handle.
652 * @param fragment_id ID of a message fragment that this client would like to
654 * @param flags Additional flags for the replay request. It is used and defined
655 * by the replay callback. FIXME: which replay callback? FIXME: use enum?
656 * FIXME: why not pass reply cb here?
657 * @return Replay request handle, NULL on error.
659 struct GNUNET_MULTICAST_MemberReplayHandle *
660 GNUNET_MULTICAST_member_replay_fragment (struct GNUNET_MULTICAST_Member *member,
661 uint64_t fragment_id,
666 * Request a message fr to be replayed.
668 * Useful if messages below the @e max_known_fragment_id given when joining are
669 * needed and not known to the client.
671 * @param member Membership handle.
672 * @param message_id ID of the message this client would like to see replayed.
673 * @param fragment_offset Offset of the fragment within the message to replay.
674 * @param flags Additional flags for the replay request. It is used & defined
675 * by the replay callback.
676 * @param result_cb Function to be called for the replayed message.
677 * @param result_cb_cls Closure for @a result_cb.
678 * @return Replay request handle, NULL on error.
680 struct GNUNET_MULTICAST_MemberReplayHandle *
681 GNUNET_MULTICAST_member_replay_message (struct GNUNET_MULTICAST_Member *member,
683 uint64_t fragment_offset,
685 GNUNET_MULTICAST_ResultCallback result_cb,
686 void *result_cb_cls);
690 * Cancel a replay request.
692 * @param rh Request to cancel.
695 GNUNET_MULTICAST_member_replay_cancel (struct GNUNET_MULTICAST_MemberReplayHandle *rh);
699 * Part a multicast group.
701 * Disconnects from all group members and invalidates the @a member handle.
703 * An application-dependent part message can be transmitted beforehand using
704 * #GNUNET_MULTICAST_member_to_origin())
706 * @param member Membership handle.
709 GNUNET_MULTICAST_member_part (struct GNUNET_MULTICAST_Member *member);
713 * Function called to provide data for a transmission from a member to the origin.
715 * Note that returning #GNUNET_OK or #GNUNET_SYSERR (but not #GNUNET_NO)
716 * invalidates the respective transmission handle.
718 * @param cls Closure.
719 * @param[in,out] data_size Initially set to the number of bytes available in
720 * @a data, should be set to the number of bytes written to data.
721 * @param[out] data Where to write the body of the message to give to the
722 * method. The function must copy at most @a data_size bytes to @a data.
723 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
724 * #GNUNET_NO on success, if more data is to be transmitted later.
725 * Should be used if @a data_size was not big enough to take all the
726 * data. If 0 is returned in @a data_size the transmission is paused,
727 * and can be resumed with GNUNET_MULTICAST_member_to_origin_resume().
728 * #GNUNET_YES if this completes the transmission (all data supplied)
731 (*GNUNET_MULTICAST_MemberTransmitNotify) (void *cls,
737 * Handle for a message to be delivered from a member to the origin.
739 struct GNUNET_MULTICAST_MemberRequestHandle;
743 * Send a message to the origin of the multicast group.
745 * @param member Membership handle.
746 * @param message_id Application layer ID for the message. Opaque to multicast.
747 * @param notify Callback to call to get the message.
748 * @param notify_cls Closure for @a notify.
749 * @return Handle to cancel request, NULL on error (i.e. request already pending).
751 struct GNUNET_MULTICAST_MemberRequestHandle *
752 GNUNET_MULTICAST_member_to_origin (struct GNUNET_MULTICAST_Member *member,
754 GNUNET_MULTICAST_MemberTransmitNotify notify,
759 * Resume message transmission to origin.
761 * @param rh Request to cancel.
764 GNUNET_MULTICAST_member_to_origin_resume (struct GNUNET_MULTICAST_MemberRequestHandle *rh);
768 * Cancel request for message transmission to origin.
770 * @param rh Request to cancel.
773 GNUNET_MULTICAST_member_to_origin_cancel (struct GNUNET_MULTICAST_MemberRequestHandle *rh);
776 #if 0 /* keep Emacsens' auto-indent happy */
783 /* ifndef GNUNET_MULTICAST_SERVICE_H */
785 /* end of gnunet_multicast_service.h */