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22 * @file include/gnunet_psyc_service.h
23 * @brief PSYC service; high-level access to the PSYC protocol
24 * note that clients of this API are NOT expected to
25 * understand the PSYC message format, only the semantics!
26 * Parsing (and serializing) the PSYC stream format is done
27 * within the implementation of the libgnunetpsyc library,
28 * and this API deliberately exposes as little as possible
29 * of the actual data stream format to the application!
30 * @author Christian Grothoff
31 * @author Gabor X Toth
34 * - this API does not know about psyc's "root" and "places";
35 * there is no 'root' in GNUnet-Psyc as we're decentralized;
36 * 'places' and 'persons' are combined within the same
37 * abstraction, that of a "channel". Channels are identified
38 * and accessed in this API using a public/private key.
39 * Higher-level applications should use NAMES within GNS
40 * to obtain public keys, and the distinction between
41 * 'places' and 'persons' can then be made with the help
42 * of the naming system (and/or conventions).
43 * Channels are (as in PSYC) organized into a hierarchy; each
44 * channel master (the one with the private key) is then
45 * the operator of the multicast group (its Origin in
46 * the terminology of the multicast API).
47 * - The API supports passing large amounts of data using
48 * 'streaming' for the argument passed to a method. State
49 * and variables must fit into memory and cannot be streamed
50 * (thus, no passing of 4 GB of data in a variable;
51 * once we implement this, we might want to create a
52 * @c \#define for the maximum size of a variable).
53 * - PSYC defines standard variables, methods, etc. This
54 * library deliberately abstracts over all of these; a
55 * higher-level API should combine the naming system (GNS)
56 * and standard methods (message, join, part, warn,
57 * fail, error) and variables (action, color, time,
58 * tag, etc.). However, this API does take over the
59 * routing variables, specifically 'context' (channel),
60 * and 'source'. We only kind-of support 'target', as
61 * the target is either everyone in the group or the
62 * origin, and never just a single member of the group;
63 * for such individual messages, an application needs to
64 * construct an 'inbox' channel where the master (only)
65 * receives messages (but never forwards; private responses
66 * would be transmitted by joining the senders 'inbox'
67 * channel -- or a inbox#bob subchannel). The
68 * goal for all of this is to keep the abstractions in this
69 * API minimal: interaction with multicast, try \& slice,
70 * state/variable/channel management. Higher-level
71 * operations belong elsewhere (so maybe this API should
72 * be called 'PSYC-low', whereas a higher-level API
73 * implementing defaults for standard methods and
74 * variables might be called 'PSYC-std' or 'PSYC-high'.
77 #ifndef GNUNET_PSYC_SERVICE_H
78 #define GNUNET_PSYC_SERVICE_H
83 #if 0 /* keep Emacsens' auto-indent happy */
88 #include "gnunet_util_lib.h"
89 #include "gnunet_env_lib.h"
90 #include "gnunet_multicast_service.h"
94 * Version number of GNUnet-PSYC API.
96 #define GNUNET_PSYC_VERSION 0x00000000
100 * Policy flags for a channel.
102 enum GNUNET_PSYC_ChannelFlags
105 * Admission must be confirmed by the master.
107 GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL = 1 << 0,
110 * Past messages are only available to slaves who were admitted at the time
111 * they were sent to the channel.
113 GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY = 1 << 1
118 * PSYC channel policies.
120 enum GNUNET_PSYC_Policy
123 * Anyone can join the channel, without announcing his presence;
124 * all messages are always public and can be distributed freely.
125 * Joins may be announced, but this is not required.
127 GNUNET_PSYC_CHANNEL_ANONYMOUS = 0,
130 * The master must approve membership to the channel, messages must only be
131 * distributed to current channel slaves. This includes the channel
132 * state as well as transient messages.
134 GNUNET_PSYC_CHANNEL_PRIVATE
135 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL
136 | GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY
140 * Anyone can freely join the channel (no approval required);
141 * however, messages must only be distributed to current channel
142 * slaves, so the master must still acknowledge that the slave
143 * joined before transient messages are delivered. As approval is
144 * guaranteed, the presistent channel state can be synchronized freely
145 * immediately, prior to master confirmation.
147 GNUNET_PSYC_CHANNEL_OPEN
148 = GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY,
151 * The master must approve joins to the channel, but past messages can be
152 * freely distributed to slaves.
154 GNUNET_PSYC_CHANNEL_CLOSED
155 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL,
160 enum GNUNET_PSYC_MessageFlags
163 * Historic message, retrieved from PSYCstore.
165 GNUNET_PSYC_MESSAGE_HISTORIC = 1 << 0,
168 * Request from slave to master.
170 GNUNET_PSYC_MESSAGE_REQUEST = 1 << 1,
173 * Message can be delivered out of order.
175 GNUNET_PSYC_MESSAGE_ORDER_ANY = 1 << 2
180 * Values for the @a state_delta field of GNUNET_PSYC_MessageHeader.
182 enum GNUNET_PSYC_StateDeltaValues
184 GNUNET_PSYC_STATE_RESET = 0,
186 GNUNET_PSYC_STATE_NOT_MODIFIED = UINT64_MAX
190 GNUNET_NETWORK_STRUCT_BEGIN
195 * Used for single-fragment messages e.g. in a join request or response.
197 struct GNUNET_PSYC_Message
200 * Message header with size and type information.
202 struct GNUNET_MessageHeader header;
204 /* Followed by concatenated PSYC message parts:
205 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
211 * Header of a PSYC message.
213 * Only present when receiving a message.
215 struct GNUNET_PSYC_MessageHeader
218 * Generic message header with size and type information.
220 struct GNUNET_MessageHeader header;
223 * Flags for this message fragment.
225 * @see enum GNUNET_PSYC_MessageFlags
227 uint32_t flags GNUNET_PACKED;
230 * Number of the message this message part belongs to.
231 * Monotonically increasing from 1.
233 uint64_t message_id GNUNET_PACKED;
236 * Byte offset of this @e fragment of the @e message.
237 * FIXME: use data_offset instead
239 uint64_t fragment_offset GNUNET_PACKED;
242 * Sending slave's public key.
243 * Not set if the message is from the master.
245 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
247 /* Followed by concatenated PSYC message parts:
248 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
254 * The method of a message.
256 struct GNUNET_PSYC_MessageMethod
259 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
261 struct GNUNET_MessageHeader header;
264 * OR'ed GNUNET_PSYC_MasterTransmitFlags
266 uint32_t flags GNUNET_PACKED;
269 * Number of message IDs since the last message that contained state
270 * operations. @see enum GNUNET_PSYC_StateDeltaValues
272 uint64_t state_delta GNUNET_PACKED;
274 /* Followed by NUL-terminated method name. */
279 * A modifier of a message.
281 struct GNUNET_PSYC_MessageModifier
284 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
286 struct GNUNET_MessageHeader header;
291 uint32_t value_size GNUNET_PACKED;
294 * Size of name, including NUL terminator.
296 uint16_t name_size GNUNET_PACKED;
299 * enum GNUNET_ENV_Operator
303 /* Followed by NUL-terminated name, then the value. */
307 struct GNUNET_PSYC_CountersResultMessage
310 * Type: GNUNET_MESSAGE_TYPE_PSYC_RESULT_COUNTERS
312 struct GNUNET_MessageHeader header;
315 * Status code for the operation.
317 int32_t result_code GNUNET_PACKED;
320 * Last message ID sent to the channel.
322 uint64_t max_message_id;
327 * Join request sent to a PSYC master.
329 struct GNUNET_PSYC_JoinRequestMessage
332 * Type: GNUNET_MESSAGE_TYPE_PSYC_MASTER_JOIN_REQUEST
334 struct GNUNET_MessageHeader header;
336 * Public key of the joining slave.
338 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
340 /* Followed by struct GNUNET_MessageHeader join_request */
345 * Join decision sent in reply to a join request.
347 struct GNUNET_PSYC_JoinDecisionMessage
350 * Type: GNUNET_MESSAGE_TYPE_PSYC_JOIN_DECISION
352 struct GNUNET_MessageHeader header;
355 * #GNUNET_YES if the slave was admitted.
360 * Public key of the joining slave.
361 * Only set when the master is sending the decision,
362 * not set when a slave is receiving it.
364 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
366 /* Followed by struct GNUNET_MessageHeader join_response */
369 GNUNET_NETWORK_STRUCT_END
372 #define GNUNET_PSYC_MODIFIER_MAX_PAYLOAD \
373 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
374 - sizeof (struct GNUNET_PSYC_MessageModifier)
376 #define GNUNET_PSYC_MOD_CONT_MAX_PAYLOAD \
377 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
378 - sizeof (struct GNUNET_MessageHeader)
380 #define GNUNET_PSYC_DATA_MAX_PAYLOAD \
381 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
382 - sizeof (struct GNUNET_MessageHeader)
386 * PSYC message part processing states.
388 enum GNUNET_PSYC_MessageState
390 GNUNET_PSYC_MESSAGE_STATE_START = 0,
391 GNUNET_PSYC_MESSAGE_STATE_HEADER = 1,
392 GNUNET_PSYC_MESSAGE_STATE_METHOD = 2,
393 GNUNET_PSYC_MESSAGE_STATE_MODIFIER = 3,
394 GNUNET_PSYC_MESSAGE_STATE_MOD_CONT = 4,
395 GNUNET_PSYC_MESSAGE_STATE_DATA = 5,
396 GNUNET_PSYC_MESSAGE_STATE_END = 6,
397 GNUNET_PSYC_MESSAGE_STATE_CANCEL = 7,
398 GNUNET_PSYC_MESSAGE_STATE_ERROR = 8,
403 * Handle that identifies a join request.
405 * Used to match calls to #GNUNET_PSYC_JoinCallback to the
406 * corresponding calls to GNUNET_PSYC_join_decision().
408 struct GNUNET_PSYC_JoinHandle;
412 * Method called from PSYC upon receiving a message.
414 * @param cls Closure.
415 * @param message_id Sequence number of the message.
416 * @param flags OR'ed GNUNET_PSYC_MessageFlags
417 * @param msg Message part, one of the following types:
420 (*GNUNET_PSYC_MessageCallback) (void *cls,
423 const struct GNUNET_PSYC_MessageHeader *msg);
427 * Method called from PSYC upon receiving part of a message.
429 * @param cls Closure.
430 * @param message_id Sequence number of the message.
431 * @param data_offset Byte offset of data, only set if @a msg has a type
432 * #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
433 * @param flags OR'ed GNUNET_PSYC_MessageFlags
434 * @param msg Message part, one of the following types:
435 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_HEADER
436 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
437 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
438 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
439 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
440 * or NULL if an error occurred while receiving a message.
443 (*GNUNET_PSYC_MessagePartCallback) (void *cls,
445 uint64_t data_offset,
447 const struct GNUNET_MessageHeader *msg);
451 * Method called from PSYC upon receiving a join request.
453 * @param cls Closure.
454 * @param slave_key Public key of the slave requesting join.
455 * @param join_msg Join message sent along with the request.
456 * @param jh Join handle to use with GNUNET_PSYC_join_decision()
459 (*GNUNET_PSYC_JoinRequestCallback) (void *cls,
460 const struct GNUNET_PSYC_JoinRequestMessage *req,
461 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
462 const struct GNUNET_PSYC_Message *join_msg,
463 struct GNUNET_PSYC_JoinHandle *jh);
467 * Function to call with the decision made for a join request.
469 * Must be called once and only once in response to an invocation of the
470 * #GNUNET_PSYC_JoinCallback.
472 * @param jh Join request handle.
474 * #GNUNET_YES if the join is approved,
475 * #GNUNET_NO if it is disapproved,
476 * #GNUNET_SYSERR if we cannot answer the request.
477 * @param relay_count Number of relays given.
478 * @param relays Array of suggested peers that might be useful relays to use
479 * when joining the multicast group (essentially a list of peers that
480 * are already part of the multicast group and might thus be willing
481 * to help with routing). If empty, only this local peer (which must
482 * be the multicast origin) is a good candidate for building the
483 * multicast tree. Note that it is unnecessary to specify our own
484 * peer identity in this array.
485 * @param join_resp Application-dependent join response message to send along
488 * @return #GNUNET_OK on success,
489 * #GNUNET_SYSERR if @a join_resp is too large.
492 GNUNET_PSYC_join_decision (struct GNUNET_PSYC_JoinHandle *jh,
494 uint32_t relay_count,
495 const struct GNUNET_PeerIdentity *relays,
496 const struct GNUNET_PSYC_Message *join_resp);
500 * Handle for the master of a PSYC channel.
502 struct GNUNET_PSYC_Master;
506 * Function called after the channel master started.
508 * @param cls Closure.
509 * @param max_message_id Last message ID sent to the channel.
512 (*GNUNET_PSYC_MasterStartCallback) (void *cls, uint64_t max_message_id);
516 * Start a PSYC master channel.
518 * Will start a multicast group identified by the given ECC key. Messages
519 * received from group members will be given to the respective handler methods.
520 * If a new member wants to join a group, the "join" method handler will be
521 * invoked; the join handler must then generate a "join" message to approve the
522 * joining of the new member. The channel can also change group membership
523 * without explicit requests. Note that PSYC doesn't itself "understand" join
524 * or part messages, the respective methods must call other PSYC functions to
525 * inform PSYC about the meaning of the respective events.
527 * @param cfg Configuration to use (to connect to PSYC service).
528 * @param channel_key ECC key that will be used to sign messages for this
529 * PSYC session. The public key is used to identify the PSYC channel.
530 * Note that end-users will usually not use the private key directly, but
531 * rather look it up in GNS for places managed by other users, or select
532 * a file with the private key(s) when setting up their own channels
533 * FIXME: we'll likely want to use NOT the p521 curve here, but a cheaper
535 * @param policy Channel policy specifying join and history restrictions.
536 * Used to automate join decisions.
537 * @param master_start_cb Function to invoke after the channel master started.
538 * @param join_request_cb Function to invoke when a slave wants to join.
539 * @param message_cb Function to invoke on message parts sent to the channel
540 * and received from slaves
541 * @param cls Closure for @a method and @a join_cb.
543 * @return Handle for the channel master, NULL on error.
545 struct GNUNET_PSYC_Master *
546 GNUNET_PSYC_master_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
547 const struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key,
548 enum GNUNET_PSYC_Policy policy,
549 GNUNET_PSYC_MasterStartCallback master_start_cb,
550 GNUNET_PSYC_JoinRequestCallback join_request_cb,
551 GNUNET_PSYC_MessageCallback message_cb,
552 GNUNET_PSYC_MessagePartCallback message_part_cb,
557 * Function called to provide data for a transmission via PSYC.
559 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
560 * invalidates the respective transmission handle.
562 * @param cls Closure.
563 * @param[in,out] data_size Initially set to the number of bytes available in
564 * @a data, should be set to the number of bytes written to data.
565 * @param[out] data Where to write the body of the message to give to the
566 * method. The function must copy at most @a data_size bytes to @a data.
567 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
568 * #GNUNET_NO on success, if more data is to be transmitted later.
569 * Should be used if @a data_size was not big enough to take all the
570 * data. If 0 is returned in @a data_size the transmission is paused,
571 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
572 * #GNUNET_YES if this completes the transmission (all data supplied)
575 (*GNUNET_PSYC_TransmitNotifyData) (void *cls,
580 * Function called to provide a modifier for a transmission via PSYC.
582 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
583 * invalidates the respective transmission handle.
585 * @param cls Closure.
586 * @param[in,out] data_size Initially set to the number of bytes available in
587 * @a data, should be set to the number of bytes written to data.
588 * @param[out] data Where to write the modifier's name and value.
589 * The function must copy at most @a data_size bytes to @a data.
590 * When this callback is first called for a modifier, @a data should
591 * contain: "name\0value". If the whole value does not fit, subsequent
592 * calls to this function should write continuations of the value to
594 * @param[out] oper Where to write the operator of the modifier.
595 * Only needed during the first call to this callback at the beginning
596 * of the modifier. In case of subsequent calls asking for value
597 * continuations @a oper is set to #NULL.
598 * @param[out] full_value_size Where to write the full size of the value.
599 * Only needed during the first call to this callback at the beginning
600 * of the modifier. In case of subsequent calls asking for value
601 * continuations @a value_size is set to #NULL.
602 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
603 * #GNUNET_NO on success, if more data is to be transmitted later.
604 * Should be used if @a data_size was not big enough to take all the
605 * data for the modifier's value (the name must be always returned
606 * during the first call to this callback).
607 * If 0 is returned in @a data_size the transmission is paused,
608 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
609 * #GNUNET_YES if this completes the modifier (the whole value is supplied).
612 (*GNUNET_PSYC_TransmitNotifyModifier) (void *cls,
616 uint32_t *full_value_size);
619 * Flags for transmitting messages to a channel by the master.
621 enum GNUNET_PSYC_MasterTransmitFlags
623 GNUNET_PSYC_MASTER_TRANSMIT_NONE = 0,
626 * Whether this message should reset the channel state,
627 * i.e. remove all previously stored state variables.
630 GNUNET_PSYC_MASTER_TRANSMIT_STATE_RESET = 1 << 0,
633 * Whether this message contains any state modifiers.
635 GNUNET_PSYC_MASTER_TRANSMIT_STATE_MODIFY = 1 << 1,
638 * Add PSYC header variable with the hash of the current channel state.
640 GNUNET_PSYC_MASTER_TRANSMIT_STATE_HASH = 1 << 2,
643 * Whether we need to increment the group generation counter after
644 * transmitting this message.
646 GNUNET_PSYC_MASTER_TRANSMIT_INC_GROUP_GEN = 1 << 3
651 * Handle for a pending PSYC transmission operation.
653 struct GNUNET_PSYC_MasterTransmitHandle;
657 * Send a message to call a method to all members in the PSYC channel.
659 * @param master Handle to the PSYC channel.
660 * @param method_name Which method should be invoked.
661 * @param notify_mod Function to call to obtain modifiers.
662 * @param notify_data Function to call to obtain fragments of the data.
663 * @param notify_cls Closure for @a notify_mod and @a notify_data.
664 * @param flags Flags for the message being transmitted.
665 * @return Transmission handle, NULL on error (i.e. more than one request queued).
667 struct GNUNET_PSYC_MasterTransmitHandle *
668 GNUNET_PSYC_master_transmit (struct GNUNET_PSYC_Master *master,
669 const char *method_name,
670 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
671 GNUNET_PSYC_TransmitNotifyData notify_data,
673 enum GNUNET_PSYC_MasterTransmitFlags flags);
677 * Resume transmission to the channel.
679 * @param th Handle of the request that is being resumed.
682 GNUNET_PSYC_master_transmit_resume (struct GNUNET_PSYC_MasterTransmitHandle *th);
686 * Abort transmission request to channel.
688 * @param th Handle of the request that is being aborted.
691 GNUNET_PSYC_master_transmit_cancel (struct GNUNET_PSYC_MasterTransmitHandle *th);
695 * Stop a PSYC master channel.
698 * PSYC channel master to stop.
700 * Keep place active after last application disconnected.
702 * Function called after the master stopped
703 * and disconnected from the psyc service.
705 * Closure for @a part_cb.
708 GNUNET_PSYC_master_stop (struct GNUNET_PSYC_Master *master,
710 GNUNET_ContinuationCallback stop_cb,
715 * Handle for a PSYC channel slave.
717 struct GNUNET_PSYC_Slave;
721 * Function called after the slave connected to the PSYC service.
723 * @param cls Closure.
724 * @param max_message_id Last message ID sent to the channel.
727 (*GNUNET_PSYC_SlaveConnectCallback) (void *cls, uint64_t max_message_id);
731 * Method called to inform about the decision in response to a join request.
733 * If @a is_admitted is not #GNUNET_YES, then sending messages to the channel is
734 * not possible, but earlier history can be still queried.
736 * @param cls Closure.
737 * @param is_admitted #GNUNET_YES or #GNUNET_NO or #GNUNET_SYSERR
738 * @param join_msg Application-dependent join message from the origin.
741 (*GNUNET_PSYC_JoinDecisionCallback) (void *cls,
742 const struct GNUNET_PSYC_JoinDecisionMessage *dcsn,
744 const struct GNUNET_PSYC_Message *join_msg);
748 * Join a PSYC channel.
750 * The entity joining is always the local peer. The user must immediately use
751 * the GNUNET_PSYC_slave_transmit() functions to transmit a @e join_msg to the
752 * channel; if the join request succeeds, the channel state (and @e recent
753 * method calls) will be replayed to the joining member. There is no explicit
754 * notification on failure (as the channel may simply take days to approve,
755 * and disapproval is simply being ignored).
757 * @param cfg Configuration to use.
758 * @param channel_key ECC public key that identifies the channel we wish to join.
759 * @param slave_key ECC private-public key pair that identifies the slave, and
760 * used by multicast to sign the join request and subsequent unicast
761 * requests sent to the master.
762 * @param origin Peer identity of the origin.
763 * @param relay_count Number of peers in the @a relays array.
764 * @param relays Peer identities of members of the multicast group, which serve
765 * as relays and used to join the group at.
766 * @param message_cb Function to invoke on message parts received from the
767 * channel, typically at least contains method handlers for @e join and
769 * @param slave_connect_cb Function invoked once we have connected to the
771 * @param join_decision_cb Function invoked once we have received a join
773 * @param cls Closure for @a message_cb and @a slave_joined_cb.
774 * @param method_name Method name for the join request.
775 * @param env Environment containing transient variables for the request, or NULL.
776 * @param data Payload for the join message.
777 * @param data_size Number of bytes in @a data.
779 * @return Handle for the slave, NULL on error.
781 struct GNUNET_PSYC_Slave *
782 GNUNET_PSYC_slave_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
783 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
784 const struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key,
785 const struct GNUNET_PeerIdentity *origin,
786 uint32_t relay_count,
787 const struct GNUNET_PeerIdentity *relays,
788 GNUNET_PSYC_MessageCallback message_cb,
789 GNUNET_PSYC_MessagePartCallback message_part_cb,
790 GNUNET_PSYC_SlaveConnectCallback slave_connect_cb,
791 GNUNET_PSYC_JoinDecisionCallback join_decision_cb,
793 const struct GNUNET_PSYC_Message *join_msg);
797 * Part a PSYC channel.
799 * Will terminate the connection to the PSYC service. Polite clients should
800 * first explicitly send a part request (via GNUNET_PSYC_slave_transmit()).
805 * Keep place active after last application disconnected.
807 * Function called after the slave parted the channel
808 * and disconnected from the psyc service.
810 * Closure for @a part_cb.
813 GNUNET_PSYC_slave_part (struct GNUNET_PSYC_Slave *slave,
815 GNUNET_ContinuationCallback part_cb,
820 * Flags for transmitting messages to the channel master by a slave.
822 enum GNUNET_PSYC_SlaveTransmitFlags
824 GNUNET_PSYC_SLAVE_TRANSMIT_NONE = 0
829 * Handle for a pending PSYC transmission operation.
831 struct GNUNET_PSYC_SlaveTransmitHandle;
835 * Request a message to be sent to the channel master.
837 * @param slave Slave handle.
838 * @param method_name Which (PSYC) method should be invoked (on host).
839 * @param notify_mod Function to call to obtain modifiers.
840 * @param notify_data Function to call to obtain fragments of the data.
841 * @param notify_cls Closure for @a notify.
842 * @param flags Flags for the message being transmitted.
843 * @return Transmission handle, NULL on error (i.e. more than one request queued).
845 struct GNUNET_PSYC_SlaveTransmitHandle *
846 GNUNET_PSYC_slave_transmit (struct GNUNET_PSYC_Slave *slave,
847 const char *method_name,
848 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
849 GNUNET_PSYC_TransmitNotifyData notify_data,
851 enum GNUNET_PSYC_SlaveTransmitFlags flags);
855 * Resume transmission to the master.
857 * @param th Handle of the request that is being resumed.
860 GNUNET_PSYC_slave_transmit_resume (struct GNUNET_PSYC_SlaveTransmitHandle *th);
864 * Abort transmission request to master.
866 * @param th Handle of the request that is being aborted.
869 GNUNET_PSYC_slave_transmit_cancel (struct GNUNET_PSYC_SlaveTransmitHandle *th);
873 * Handle to access PSYC channel operations for both the master and slaves.
875 struct GNUNET_PSYC_Channel;
879 * Convert a channel @a master to a @e channel handle to access the @e channel
882 * @param master Channel master handle.
883 * @return Channel handle, valid for as long as @a master is valid.
885 struct GNUNET_PSYC_Channel *
886 GNUNET_PSYC_master_get_channel (struct GNUNET_PSYC_Master *master);
890 * Convert @a slave to a @e channel handle to access the @e channel APIs.
892 * @param slave Slave handle.
893 * @return Channel handle, valid for as long as @a slave is valid.
895 struct GNUNET_PSYC_Channel *
896 GNUNET_PSYC_slave_get_channel (struct GNUNET_PSYC_Slave *slave);
900 * Add a slave to the channel's membership list.
902 * Note that this will NOT generate any PSYC traffic, it will merely update the
903 * local database to modify how we react to <em>membership test</em> queries.
904 * The channel master still needs to explicitly transmit a @e join message to
905 * notify other channel members and they then also must still call this function
906 * in their respective methods handling the @e join message. This way, how @e
907 * join and @e part operations are exactly implemented is still up to the
908 * application; for example, there might be a @e part_all method to kick out
911 * Note that channel slaves are explicitly trusted to execute such methods
912 * correctly; not doing so correctly will result in either denying other slaves
913 * access or offering access to channel data to non-members.
915 * @param channel Channel handle.
916 * @param slave_key Identity of channel slave to add.
917 * @param announced_at ID of the message that announced the membership change.
918 * @param effective_since Addition of slave is in effect since this message ID.
921 GNUNET_PSYC_channel_slave_add (struct GNUNET_PSYC_Channel *channel,
922 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
923 uint64_t announced_at,
924 uint64_t effective_since);
928 * Remove a slave from the channel's membership list.
930 * Note that this will NOT generate any PSYC traffic, it will merely update the
931 * local database to modify how we react to <em>membership test</em> queries.
932 * The channel master still needs to explicitly transmit a @e part message to
933 * notify other channel members and they then also must still call this function
934 * in their respective methods handling the @e part message. This way, how
935 * @e join and @e part operations are exactly implemented is still up to the
936 * application; for example, there might be a @e part_all message to kick out
939 * Note that channel members are explicitly trusted to perform these
940 * operations correctly; not doing so correctly will result in either
941 * denying members access or offering access to channel data to
944 * @param channel Channel handle.
945 * @param slave_key Identity of channel slave to remove.
946 * @param announced_at ID of the message that announced the membership change.
949 GNUNET_PSYC_channel_slave_remove (struct GNUNET_PSYC_Channel *channel,
950 const struct GNUNET_CRYPTO_EcdsaPublicKey
952 uint64_t announced_at);
956 * Function called to inform a member about stored state values for a channel.
958 * @param cls Closure.
959 * @param name Name of the state variable. A NULL value indicates that there
960 * are no more state variables to be returned.
961 * @param value Value of the state variable.
962 * @param value_size Number of bytes in @a value.
965 (*GNUNET_PSYC_StateCallback) (void *cls,
972 * Function called when a requested operation has finished.
974 * @param cls Closure.
977 (*GNUNET_PSYC_FinishCallback) (void *cls);
981 * Handle to a story telling operation.
983 struct GNUNET_PSYC_Story;
987 * Request to be told the message history of the channel.
989 * Historic messages (but NOT the state at the time) will be replayed (given to
990 * the normal method handlers) if available and if access is permitted.
992 * To get the latest message, use 0 for both the start and end message ID.
994 * @param channel Which channel should be replayed?
995 * @param start_message_id Earliest interesting point in history.
996 * @param end_message_id Last (exclusive) interesting point in history.
997 * @param message_cb Function to invoke on message parts received from the story.
998 * @param finish_cb Function to call when the requested story has been fully
999 * told (counting message IDs might not suffice, as some messages
1000 * might be secret and thus the listener would not know the story is
1001 * finished without being told explicitly); once this function
1002 * has been called, the client must not call
1003 * GNUNET_PSYC_channel_story_tell_cancel() anymore.
1004 * @param cls Closure for the callbacks.
1005 * @return Handle to cancel story telling operation.
1007 struct GNUNET_PSYC_Story *
1008 GNUNET_PSYC_channel_story_tell (struct GNUNET_PSYC_Channel *channel,
1009 uint64_t start_message_id,
1010 uint64_t end_message_id,
1011 GNUNET_PSYC_MessageCallback message_cb,
1012 GNUNET_PSYC_MessagePartCallback message_part_cb,
1013 GNUNET_PSYC_FinishCallback finish_cb,
1018 * Abort story telling.
1020 * This function must not be called from within method handlers (as given to
1021 * GNUNET_PSYC_slave_join()) of the slave.
1023 * @param story Story telling operation to stop.
1026 GNUNET_PSYC_channel_story_tell_cancel (struct GNUNET_PSYC_Story *story);
1030 * Handle for a state query operation.
1032 struct GNUNET_PSYC_StateQuery;
1036 * Retrieve the best matching channel state variable.
1038 * If the requested variable name is not present in the state, the nearest
1039 * less-specific name is matched; for example, requesting "_a_b" will match "_a"
1040 * if "_a_b" does not exist.
1042 * @param channel Channel handle.
1043 * @param full_name Full name of the requested variable, the actual variable
1044 * returned might have a shorter name..
1045 * @param cb Function called once when a matching state variable is found.
1046 * Not called if there's no matching state variable.
1047 * @param cb_cls Closure for the callbacks.
1048 * @return Handle that can be used to cancel the query operation.
1050 struct GNUNET_PSYC_StateQuery *
1051 GNUNET_PSYC_channel_state_get (struct GNUNET_PSYC_Channel *channel,
1052 const char *full_name,
1053 GNUNET_PSYC_StateCallback cb,
1058 * Return all channel state variables whose name matches a given prefix.
1060 * A name matches if it starts with the given @a name_prefix, thus requesting
1061 * the empty prefix ("") will match all values; requesting "_a_b" will also
1062 * return values stored under "_a_b_c".
1064 * The @a state_cb is invoked on all matching state variables asynchronously, as
1065 * the state is stored in and retrieved from the PSYCstore,
1067 * @param channel Channel handle.
1068 * @param name_prefix Prefix of the state variable name to match.
1069 * @param cb Function to call with the matching state variables.
1070 * @param cb_cls Closure for the callbacks.
1071 * @return Handle that can be used to cancel the query operation.
1073 struct GNUNET_PSYC_StateQuery *
1074 GNUNET_PSYC_channel_state_get_prefix (struct GNUNET_PSYC_Channel *channel,
1075 const char *name_prefix,
1076 GNUNET_PSYC_StateCallback cb,
1081 * Cancel a state query operation.
1083 * @param query Handle for the operation to cancel.
1086 GNUNET_PSYC_channel_state_get_cancel (struct GNUNET_PSYC_StateQuery *query);
1089 #if 0 /* keep Emacsens' auto-indent happy */
1096 /* ifndef GNUNET_PSYC_SERVICE_H */
1098 /* end of gnunet_psyc_service.h */