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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 # define UINT64_MAX 0xffffffffffffffffULL
99 * Version number of GNUnet-PSYC API.
101 #define GNUNET_PSYC_VERSION 0x00000000
105 * Policy flags for a channel.
107 enum GNUNET_PSYC_ChannelFlags
110 * Admission must be confirmed by the master.
112 GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL = 1 << 0,
115 * Past messages are only available to slaves who were admitted at the time
116 * they were sent to the channel.
118 GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY = 1 << 1
123 * PSYC channel policies.
125 enum GNUNET_PSYC_Policy
128 * Anyone can join the channel, without announcing his presence;
129 * all messages are always public and can be distributed freely.
130 * Joins may be announced, but this is not required.
132 GNUNET_PSYC_CHANNEL_ANONYMOUS = 0,
135 * The master must approve membership to the channel, messages must only be
136 * distributed to current channel slaves. This includes the channel
137 * state as well as transient messages.
139 GNUNET_PSYC_CHANNEL_PRIVATE
140 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL
141 | GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY
145 * Anyone can freely join the channel (no approval required);
146 * however, messages must only be distributed to current channel
147 * slaves, so the master must still acknowledge that the slave
148 * joined before transient messages are delivered. As approval is
149 * guaranteed, the presistent channel state can be synchronized freely
150 * immediately, prior to master confirmation.
152 GNUNET_PSYC_CHANNEL_OPEN
153 = GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY,
156 * The master must approve joins to the channel, but past messages can be
157 * freely distributed to slaves.
159 GNUNET_PSYC_CHANNEL_CLOSED
160 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL,
165 enum GNUNET_PSYC_MessageFlags
168 * Default / no flags.
170 GNUNET_PSYC_MESSAGE_DEFAULT = 0,
173 * Historic message, retrieved from PSYCstore.
175 GNUNET_PSYC_MESSAGE_HISTORIC = 1 << 0,
178 * Request from slave to master.
180 GNUNET_PSYC_MESSAGE_REQUEST = 1 << 1,
183 * Message can be delivered out of order.
185 GNUNET_PSYC_MESSAGE_ORDER_ANY = 1 << 2
190 * Values for the @a state_delta field of GNUNET_PSYC_MessageHeader.
192 enum GNUNET_PSYC_StateDeltaValues
194 GNUNET_PSYC_STATE_RESET = 0,
196 GNUNET_PSYC_STATE_NOT_MODIFIED = UINT64_MAX
200 GNUNET_NETWORK_STRUCT_BEGIN
205 * Used for single-fragment messages e.g. in a join request or response.
207 struct GNUNET_PSYC_Message
210 * Message header with size and type information.
212 struct GNUNET_MessageHeader header;
214 /* Followed by concatenated PSYC message parts:
215 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
221 * Header of a PSYC message.
223 * Only present when receiving a message.
225 struct GNUNET_PSYC_MessageHeader
228 * Generic message header with size and type information.
230 struct GNUNET_MessageHeader header;
233 * Flags for this message fragment.
235 * @see enum GNUNET_PSYC_MessageFlags
237 uint32_t flags GNUNET_PACKED;
240 * Number of the message this message part belongs to.
241 * Monotonically increasing from 1.
243 uint64_t message_id GNUNET_PACKED;
246 * Byte offset of this @e fragment of the @e message.
247 * FIXME: use data_offset instead
249 uint64_t fragment_offset GNUNET_PACKED;
252 * Sending slave's public key.
253 * Not set if the message is from the master.
255 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
257 /* Followed by concatenated PSYC message parts:
258 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
264 * The method of a message.
266 struct GNUNET_PSYC_MessageMethod
269 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
271 struct GNUNET_MessageHeader header;
274 * OR'ed GNUNET_PSYC_MasterTransmitFlags
276 uint32_t flags GNUNET_PACKED;
279 * Number of message IDs since the last message that contained state
280 * operations. @see enum GNUNET_PSYC_StateDeltaValues
282 uint64_t state_delta GNUNET_PACKED;
284 /* Followed by NUL-terminated method name. */
289 * A modifier of a message.
291 struct GNUNET_PSYC_MessageModifier
294 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
296 struct GNUNET_MessageHeader header;
301 uint32_t value_size GNUNET_PACKED;
304 * Size of name, including NUL terminator.
306 uint16_t name_size GNUNET_PACKED;
309 * enum GNUNET_ENV_Operator
313 /* Followed by NUL-terminated name, then the value. */
317 struct GNUNET_PSYC_CountersResultMessage
320 * Type: GNUNET_MESSAGE_TYPE_PSYC_RESULT_COUNTERS
322 struct GNUNET_MessageHeader header;
325 * Status code for the operation.
327 uint32_t result_code GNUNET_PACKED;
330 * Last message ID sent to the channel.
332 uint64_t max_message_id GNUNET_PACKED;
337 * Join request sent to a PSYC master.
339 struct GNUNET_PSYC_JoinRequestMessage
342 * Type: GNUNET_MESSAGE_TYPE_PSYC_MASTER_JOIN_REQUEST
344 struct GNUNET_MessageHeader header;
346 * Public key of the joining slave.
348 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
350 /* Followed by struct GNUNET_MessageHeader join_request */
355 * Join decision sent in reply to a join request.
357 struct GNUNET_PSYC_JoinDecisionMessage
360 * Type: GNUNET_MESSAGE_TYPE_PSYC_JOIN_DECISION
362 struct GNUNET_MessageHeader header;
365 * #GNUNET_YES if the slave was admitted.
370 * Public key of the joining slave.
371 * Only set when the master is sending the decision,
372 * not set when a slave is receiving it.
374 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
376 /* Followed by struct GNUNET_MessageHeader join_response */
380 enum GNUNET_PSYC_HistoryReplayFlags
383 * Replay locally available messages.
385 GNUNET_PSYC_HISTORY_REPLAY_LOCAL = 0,
388 * Replay messages from remote peers if not found locally.
390 GNUNET_PSYC_HISTORY_REPLAY_REMOTE = 1,
394 struct GNUNET_PSYC_HistoryRequestMessage
397 * Type: GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_HISTORY_REPLAY
399 struct GNUNET_MessageHeader header;
402 * @see enum GNUNET_PSYC_HistoryReplayFlags
404 uint32_t flags GNUNET_PACKED;
407 * ID for this operation.
409 uint64_t op_id GNUNET_PACKED;
411 uint64_t start_message_id GNUNET_PACKED;
413 uint64_t end_message_id GNUNET_PACKED;
415 uint64_t message_limit GNUNET_PACKED;
417 /* Followed by NUL-terminated method name prefix. */
421 struct GNUNET_PSYC_StateRequestMessage
425 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET
426 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET_PREFIX
428 struct GNUNET_MessageHeader header;
430 uint32_t reserved GNUNET_PACKED;
433 * ID for this operation.
435 uint64_t op_id GNUNET_PACKED;
437 /* Followed by NUL-terminated name. */
441 /**** service -> library ****/
445 * Answer from service to client about last operation.
447 struct GNUNET_PSYC_OperationResultMessage
451 * - GNUNET_MESSAGE_TYPE_PSYC_RESULT_CODE
452 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_RESULT
454 struct GNUNET_MessageHeader header;
456 uint32_t reserved GNUNET_PACKED;
461 uint64_t op_id GNUNET_PACKED;
464 * Status code for the operation.
466 uint64_t result_code GNUNET_PACKED;
469 * - on error: NUL-terminated error message
470 * - on success: one of the following message types
472 * For a STATE_RESULT, one of:
473 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
474 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
475 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_END
479 GNUNET_NETWORK_STRUCT_END
482 #define GNUNET_PSYC_MODIFIER_MAX_PAYLOAD \
483 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
484 - sizeof (struct GNUNET_PSYC_MessageModifier)
486 #define GNUNET_PSYC_MOD_CONT_MAX_PAYLOAD \
487 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
488 - sizeof (struct GNUNET_MessageHeader)
490 #define GNUNET_PSYC_DATA_MAX_PAYLOAD \
491 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
492 - sizeof (struct GNUNET_MessageHeader)
496 * PSYC message part processing states.
498 enum GNUNET_PSYC_MessageState
500 GNUNET_PSYC_MESSAGE_STATE_START = 0,
501 GNUNET_PSYC_MESSAGE_STATE_HEADER = 1,
502 GNUNET_PSYC_MESSAGE_STATE_METHOD = 2,
503 GNUNET_PSYC_MESSAGE_STATE_MODIFIER = 3,
504 GNUNET_PSYC_MESSAGE_STATE_MOD_CONT = 4,
505 GNUNET_PSYC_MESSAGE_STATE_DATA = 5,
506 GNUNET_PSYC_MESSAGE_STATE_END = 6,
507 GNUNET_PSYC_MESSAGE_STATE_CANCEL = 7,
508 GNUNET_PSYC_MESSAGE_STATE_ERROR = 8,
513 * Handle that identifies a join request.
515 * Used to match calls to #GNUNET_PSYC_JoinCallback to the
516 * corresponding calls to GNUNET_PSYC_join_decision().
518 struct GNUNET_PSYC_JoinHandle;
522 * Method called from PSYC upon receiving a message.
524 * @param cls Closure.
525 * @param message_id Sequence number of the message.
526 * @param flags OR'ed GNUNET_PSYC_MessageFlags
527 * @param msg Message part, one of the following types:
530 (*GNUNET_PSYC_MessageCallback) (void *cls,
533 const struct GNUNET_PSYC_MessageHeader *msg);
537 * Method called from PSYC upon receiving part of a message.
539 * @param cls Closure.
540 * @param message_id Sequence number of the message.
541 * @param data_offset Byte offset of data, only set if @a msg has a type
542 * #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
543 * @param flags OR'ed GNUNET_PSYC_MessageFlags
544 * @param msg Message part, one of the following types:
545 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_HEADER
546 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
547 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
548 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
549 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
550 * or NULL if an error occurred while receiving a message.
553 (*GNUNET_PSYC_MessagePartCallback) (void *cls,
555 uint64_t data_offset,
557 const struct GNUNET_MessageHeader *msg);
561 * Method called from PSYC upon receiving a join request.
563 * @param cls Closure.
564 * @param slave_key Public key of the slave requesting join.
565 * @param join_msg Join message sent along with the request.
566 * @param jh Join handle to use with GNUNET_PSYC_join_decision()
569 (*GNUNET_PSYC_JoinRequestCallback) (void *cls,
570 const struct GNUNET_PSYC_JoinRequestMessage *req,
571 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
572 const struct GNUNET_PSYC_Message *join_msg,
573 struct GNUNET_PSYC_JoinHandle *jh);
577 * Function to call with the decision made for a join request.
579 * Must be called once and only once in response to an invocation of the
580 * #GNUNET_PSYC_JoinCallback.
582 * @param jh Join request handle.
584 * #GNUNET_YES if the join is approved,
585 * #GNUNET_NO if it is disapproved,
586 * #GNUNET_SYSERR if we cannot answer the request.
587 * @param relay_count Number of relays given.
588 * @param relays Array of suggested peers that might be useful relays to use
589 * when joining the multicast group (essentially a list of peers that
590 * are already part of the multicast group and might thus be willing
591 * to help with routing). If empty, only this local peer (which must
592 * be the multicast origin) is a good candidate for building the
593 * multicast tree. Note that it is unnecessary to specify our own
594 * peer identity in this array.
595 * @param join_resp Application-dependent join response message to send along
598 * @return #GNUNET_OK on success,
599 * #GNUNET_SYSERR if @a join_resp is too large.
602 GNUNET_PSYC_join_decision (struct GNUNET_PSYC_JoinHandle *jh,
604 uint32_t relay_count,
605 const struct GNUNET_PeerIdentity *relays,
606 const struct GNUNET_PSYC_Message *join_resp);
610 * Handle for the master of a PSYC channel.
612 struct GNUNET_PSYC_Master;
616 * Function called after connected to the PSYC service
617 * and the channel master started.
619 * Also called when reconnected to the service
620 * after the connection closed unexpectedly.
625 * #GNUNET_YES if there were already messages sent to the channel,
626 * #GNUNET_NO if the message history is empty,
627 * #GNUNET_SYSERR on error.
628 * @param max_message_id
629 * Last message ID sent to the channel.
632 (*GNUNET_PSYC_MasterStartCallback) (void *cls, int result,
633 uint64_t max_message_id);
637 * Start a PSYC master channel.
639 * Will start a multicast group identified by the given ECC key. Messages
640 * received from group members will be given to the respective handler methods.
641 * If a new member wants to join a group, the "join" method handler will be
642 * invoked; the join handler must then generate a "join" message to approve the
643 * joining of the new member. The channel can also change group membership
644 * without explicit requests. Note that PSYC doesn't itself "understand" join
645 * or part messages, the respective methods must call other PSYC functions to
646 * inform PSYC about the meaning of the respective events.
648 * @param cfg Configuration to use (to connect to PSYC service).
649 * @param channel_key ECC key that will be used to sign messages for this
650 * PSYC session. The public key is used to identify the PSYC channel.
651 * Note that end-users will usually not use the private key directly, but
652 * rather look it up in GNS for places managed by other users, or select
653 * a file with the private key(s) when setting up their own channels
654 * FIXME: we'll likely want to use NOT the p521 curve here, but a cheaper
656 * @param policy Channel policy specifying join and history restrictions.
657 * Used to automate join decisions.
658 * @param master_start_cb Function to invoke after the channel master started.
659 * @param join_request_cb Function to invoke when a slave wants to join.
660 * @param message_cb Function to invoke on message parts sent to the channel
661 * and received from slaves
662 * @param cls Closure for @a method and @a join_cb.
664 * @return Handle for the channel master, NULL on error.
666 struct GNUNET_PSYC_Master *
667 GNUNET_PSYC_master_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
668 const struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key,
669 enum GNUNET_PSYC_Policy policy,
670 GNUNET_PSYC_MasterStartCallback master_start_cb,
671 GNUNET_PSYC_JoinRequestCallback join_request_cb,
672 GNUNET_PSYC_MessageCallback message_cb,
673 GNUNET_PSYC_MessagePartCallback message_part_cb,
678 * Function called to provide data for a transmission via PSYC.
680 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
681 * invalidates the respective transmission handle.
683 * @param cls Closure.
684 * @param[in,out] data_size Initially set to the number of bytes available in
685 * @a data, should be set to the number of bytes written to data.
686 * @param[out] data Where to write the body of the message to give to the
687 * method. The function must copy at most @a data_size bytes to @a data.
688 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
689 * #GNUNET_NO on success, if more data is to be transmitted later.
690 * Should be used if @a data_size was not big enough to take all the
691 * data. If 0 is returned in @a data_size the transmission is paused,
692 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
693 * #GNUNET_YES if this completes the transmission (all data supplied)
696 (*GNUNET_PSYC_TransmitNotifyData) (void *cls,
701 * Function called to provide a modifier for a transmission via PSYC.
703 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
704 * invalidates the respective transmission handle.
706 * @param cls Closure.
707 * @param[in,out] data_size Initially set to the number of bytes available in
708 * @a data, should be set to the number of bytes written to data.
709 * @param[out] data Where to write the modifier's name and value.
710 * The function must copy at most @a data_size bytes to @a data.
711 * When this callback is first called for a modifier, @a data should
712 * contain: "name\0value". If the whole value does not fit, subsequent
713 * calls to this function should write continuations of the value to
715 * @param[out] oper Where to write the operator of the modifier.
716 * Only needed during the first call to this callback at the beginning
717 * of the modifier. In case of subsequent calls asking for value
718 * continuations @a oper is set to #NULL.
719 * @param[out] full_value_size Where to write the full size of the value.
720 * Only needed during the first call to this callback at the beginning
721 * of the modifier. In case of subsequent calls asking for value
722 * continuations @a value_size is set to #NULL.
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 for the modifier's value (the name must be always returned
727 * during the first call to this callback).
728 * If 0 is returned in @a data_size the transmission is paused,
729 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
730 * #GNUNET_YES if this completes the modifier (the whole value is supplied).
733 (*GNUNET_PSYC_TransmitNotifyModifier) (void *cls,
737 uint32_t *full_value_size);
740 * Flags for transmitting messages to a channel by the master.
742 enum GNUNET_PSYC_MasterTransmitFlags
744 GNUNET_PSYC_MASTER_TRANSMIT_NONE = 0,
747 * Whether this message should reset the channel state,
748 * i.e. remove all previously stored state variables.
751 GNUNET_PSYC_MASTER_TRANSMIT_STATE_RESET = 1 << 0,
754 * Whether this message contains any state modifiers.
756 GNUNET_PSYC_MASTER_TRANSMIT_STATE_MODIFY = 1 << 1,
759 * Add PSYC header variable with the hash of the current channel state.
761 GNUNET_PSYC_MASTER_TRANSMIT_STATE_HASH = 1 << 2,
764 * Whether we need to increment the group generation counter after
765 * transmitting this message.
767 GNUNET_PSYC_MASTER_TRANSMIT_INC_GROUP_GEN = 1 << 3
772 * Handle for a pending PSYC transmission operation.
774 struct GNUNET_PSYC_MasterTransmitHandle;
778 * Send a message to call a method to all members in the PSYC channel.
780 * @param master Handle to the PSYC channel.
781 * @param method_name Which method should be invoked.
782 * @param notify_mod Function to call to obtain modifiers.
783 * @param notify_data Function to call to obtain fragments of the data.
784 * @param notify_cls Closure for @a notify_mod and @a notify_data.
785 * @param flags Flags for the message being transmitted.
786 * @return Transmission handle, NULL on error (i.e. more than one request queued).
788 struct GNUNET_PSYC_MasterTransmitHandle *
789 GNUNET_PSYC_master_transmit (struct GNUNET_PSYC_Master *master,
790 const char *method_name,
791 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
792 GNUNET_PSYC_TransmitNotifyData notify_data,
794 enum GNUNET_PSYC_MasterTransmitFlags flags);
798 * Resume transmission to the channel.
800 * @param th Handle of the request that is being resumed.
803 GNUNET_PSYC_master_transmit_resume (struct GNUNET_PSYC_MasterTransmitHandle *th);
807 * Abort transmission request to channel.
809 * @param th Handle of the request that is being aborted.
812 GNUNET_PSYC_master_transmit_cancel (struct GNUNET_PSYC_MasterTransmitHandle *th);
816 * Stop a PSYC master channel.
819 * PSYC channel master to stop.
821 * Keep place active after last application disconnected.
823 * Function called after the master stopped
824 * and disconnected from the psyc service.
826 * Closure for @a part_cb.
829 GNUNET_PSYC_master_stop (struct GNUNET_PSYC_Master *master,
831 GNUNET_ContinuationCallback stop_cb,
836 * Handle for a PSYC channel slave.
838 struct GNUNET_PSYC_Slave;
842 * Function called after the slave connected to the PSYC service.
844 * Also called when reconnected to the service
845 * after the connection closed unexpectedly.
850 * #GNUNET_YES if there were already messages sent to the channel,
851 * #GNUNET_NO if the message history is empty,
852 * #GNUNET_SYSERR on error.
853 * @param max_message_id
854 * Last message ID sent to the channel.
857 (*GNUNET_PSYC_SlaveConnectCallback) (void *cls, int result,
858 uint64_t max_message_id);
862 * Method called to inform about the decision in response to a join request.
864 * If @a is_admitted is not #GNUNET_YES, then sending messages to the channel is
865 * not possible, but earlier history can be still queried.
867 * @param cls Closure.
868 * @param is_admitted #GNUNET_YES or #GNUNET_NO or #GNUNET_SYSERR
869 * @param join_msg Application-dependent join message from the origin.
872 (*GNUNET_PSYC_JoinDecisionCallback) (void *cls,
873 const struct GNUNET_PSYC_JoinDecisionMessage *dcsn,
875 const struct GNUNET_PSYC_Message *join_msg);
879 * Join a PSYC channel.
881 * The entity joining is always the local peer. The user must immediately use
882 * the GNUNET_PSYC_slave_transmit() functions to transmit a @e join_msg to the
883 * channel; if the join request succeeds, the channel state (and @e recent
884 * method calls) will be replayed to the joining member. There is no explicit
885 * notification on failure (as the channel may simply take days to approve,
886 * and disapproval is simply being ignored).
888 * @param cfg Configuration to use.
889 * @param channel_key ECC public key that identifies the channel we wish to join.
890 * @param slave_key ECC private-public key pair that identifies the slave, and
891 * used by multicast to sign the join request and subsequent unicast
892 * requests sent to the master.
893 * @param origin Peer identity of the origin.
894 * @param relay_count Number of peers in the @a relays array.
895 * @param relays Peer identities of members of the multicast group, which serve
896 * as relays and used to join the group at.
897 * @param message_cb Function to invoke on message parts received from the
898 * channel, typically at least contains method handlers for @e join and
900 * @param slave_connect_cb Function invoked once we have connected to the
902 * @param join_decision_cb Function invoked once we have received a join
904 * @param cls Closure for @a message_cb and @a slave_joined_cb.
905 * @param method_name Method name for the join request.
906 * @param env Environment containing transient variables for the request, or NULL.
907 * @param data Payload for the join message.
908 * @param data_size Number of bytes in @a data.
910 * @return Handle for the slave, NULL on error.
912 struct GNUNET_PSYC_Slave *
913 GNUNET_PSYC_slave_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
914 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
915 const struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key,
916 const struct GNUNET_PeerIdentity *origin,
917 uint32_t relay_count,
918 const struct GNUNET_PeerIdentity *relays,
919 GNUNET_PSYC_MessageCallback message_cb,
920 GNUNET_PSYC_MessagePartCallback message_part_cb,
921 GNUNET_PSYC_SlaveConnectCallback slave_connect_cb,
922 GNUNET_PSYC_JoinDecisionCallback join_decision_cb,
924 const struct GNUNET_PSYC_Message *join_msg);
928 * Part a PSYC channel.
930 * Will terminate the connection to the PSYC service. Polite clients should
931 * first explicitly send a part request (via GNUNET_PSYC_slave_transmit()).
936 * Keep place active after last application disconnected.
938 * Function called after the slave parted the channel
939 * and disconnected from the psyc service.
941 * Closure for @a part_cb.
944 GNUNET_PSYC_slave_part (struct GNUNET_PSYC_Slave *slave,
946 GNUNET_ContinuationCallback part_cb,
951 * Flags for transmitting messages to the channel master by a slave.
953 enum GNUNET_PSYC_SlaveTransmitFlags
955 GNUNET_PSYC_SLAVE_TRANSMIT_NONE = 0
960 * Handle for a pending PSYC transmission operation.
962 struct GNUNET_PSYC_SlaveTransmitHandle;
966 * Request a message to be sent to the channel master.
968 * @param slave Slave handle.
969 * @param method_name Which (PSYC) method should be invoked (on host).
970 * @param notify_mod Function to call to obtain modifiers.
971 * @param notify_data Function to call to obtain fragments of the data.
972 * @param notify_cls Closure for @a notify.
973 * @param flags Flags for the message being transmitted.
974 * @return Transmission handle, NULL on error (i.e. more than one request queued).
976 struct GNUNET_PSYC_SlaveTransmitHandle *
977 GNUNET_PSYC_slave_transmit (struct GNUNET_PSYC_Slave *slave,
978 const char *method_name,
979 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
980 GNUNET_PSYC_TransmitNotifyData notify_data,
982 enum GNUNET_PSYC_SlaveTransmitFlags flags);
986 * Resume transmission to the master.
988 * @param th Handle of the request that is being resumed.
991 GNUNET_PSYC_slave_transmit_resume (struct GNUNET_PSYC_SlaveTransmitHandle *th);
995 * Abort transmission request to master.
997 * @param th Handle of the request that is being aborted.
1000 GNUNET_PSYC_slave_transmit_cancel (struct GNUNET_PSYC_SlaveTransmitHandle *th);
1004 * Handle to access PSYC channel operations for both the master and slaves.
1006 struct GNUNET_PSYC_Channel;
1010 * Convert a channel @a master to a @e channel handle to access the @e channel
1013 * @param master Channel master handle.
1014 * @return Channel handle, valid for as long as @a master is valid.
1016 struct GNUNET_PSYC_Channel *
1017 GNUNET_PSYC_master_get_channel (struct GNUNET_PSYC_Master *master);
1021 * Convert @a slave to a @e channel handle to access the @e channel APIs.
1023 * @param slave Slave handle.
1024 * @return Channel handle, valid for as long as @a slave is valid.
1026 struct GNUNET_PSYC_Channel *
1027 GNUNET_PSYC_slave_get_channel (struct GNUNET_PSYC_Slave *slave);
1031 * Add a slave to the channel's membership list.
1033 * Note that this will NOT generate any PSYC traffic, it will merely update the
1034 * local database to modify how we react to <em>membership test</em> queries.
1035 * The channel master still needs to explicitly transmit a @e join message to
1036 * notify other channel members and they then also must still call this function
1037 * in their respective methods handling the @e join message. This way, how @e
1038 * join and @e part operations are exactly implemented is still up to the
1039 * application; for example, there might be a @e part_all method to kick out
1042 * Note that channel slaves are explicitly trusted to execute such methods
1043 * correctly; not doing so correctly will result in either denying other slaves
1044 * access or offering access to channel data to non-members.
1049 * Identity of channel slave to add.
1050 * @param announced_at
1051 * ID of the message that announced the membership change.
1052 * @param effective_since
1053 * Addition of slave is in effect since this message ID.
1055 * Function to call with the result of the operation.
1056 * The @e result_code argument is #GNUNET_OK on success, or
1057 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1058 * can contain an optional error message.
1060 * Closure for @a result_cb.
1063 GNUNET_PSYC_channel_slave_add (struct GNUNET_PSYC_Channel *channel,
1064 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
1065 uint64_t announced_at,
1066 uint64_t effective_since,
1067 GNUNET_ResultCallback result_cb,
1072 * Remove a slave from the channel's membership list.
1074 * Note that this will NOT generate any PSYC traffic, it will merely update the
1075 * local database to modify how we react to <em>membership test</em> queries.
1076 * The channel master still needs to explicitly transmit a @e part message to
1077 * notify other channel members and they then also must still call this function
1078 * in their respective methods handling the @e part message. This way, how
1079 * @e join and @e part operations are exactly implemented is still up to the
1080 * application; for example, there might be a @e part_all message to kick out
1083 * Note that channel members are explicitly trusted to perform these
1084 * operations correctly; not doing so correctly will result in either
1085 * denying members access or offering access to channel data to
1091 * Identity of channel slave to remove.
1092 * @param announced_at
1093 * ID of the message that announced the membership change.
1095 * Function to call with the result of the operation.
1096 * The @e result_code argument is #GNUNET_OK on success, or
1097 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1098 * can contain an optional error message.
1100 * Closure for @a result_cb.
1103 GNUNET_PSYC_channel_slave_remove (struct GNUNET_PSYC_Channel *channel,
1104 const struct GNUNET_CRYPTO_EcdsaPublicKey
1106 uint64_t announced_at,
1107 GNUNET_ResultCallback result_cb,
1112 * History request handle.
1114 struct GNUNET_PSYC_HistoryRequest;
1118 * Request to replay a part of the message history of the channel.
1120 * Historic messages (but NOT the state at the time) will be replayed (given to
1121 * the normal method handlers) if available and if access is permitted.
1124 * Which channel should be replayed?
1125 * @param start_message_id
1126 * Earliest interesting point in history.
1127 * @param end_message_id
1128 * Last (inclusive) interesting point in history.
1129 * @param method_prefix
1130 * Retrieve only messages with a matching method prefix.
1132 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1134 * Function to call when the requested history has been fully replayed.
1135 * Once this function has been called, the client must not call
1136 * GNUNET_PSYC_channel_history_replay_cancel() anymore.
1138 * Closure for the callbacks.
1140 * @return Handle to cancel history replay operation.
1142 struct GNUNET_PSYC_HistoryRequest *
1143 GNUNET_PSYC_channel_history_replay (struct GNUNET_PSYC_Channel *channel,
1144 uint64_t start_message_id,
1145 uint64_t end_message_id,
1146 const char *method_prefix,
1148 GNUNET_PSYC_MessageCallback message_cb,
1149 GNUNET_PSYC_MessagePartCallback message_part_cb,
1150 GNUNET_ResultCallback result_cb,
1155 * Request to replay the latest messages from the message history of the channel.
1157 * Historic messages (but NOT the state at the time) will be replayed (given to
1158 * the normal method handlers) if available and if access is permitted.
1161 * Which channel should be replayed?
1162 * @param message_limit
1163 * Maximum number of messages to replay.
1165 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1167 * Function to call when the requested history has been fully replayed
1168 * (counting message IDs might not suffice, as some messages might be
1169 * secret and thus the listener would not know the story is finished
1170 * without being told explicitly)o once this function has been called, the
1171 * client must not call GNUNET_PSYC_channel_history_replay_cancel() anymore.
1173 * Closure for the callbacks.
1175 * @return Handle to cancel history replay operation.
1177 struct GNUNET_PSYC_HistoryRequest *
1178 GNUNET_PSYC_channel_history_replay_latest (struct GNUNET_PSYC_Channel *channel,
1179 uint64_t message_limit,
1180 const char *method_prefix,
1182 GNUNET_PSYC_MessageCallback message_cb,
1183 GNUNET_PSYC_MessagePartCallback message_part_cb,
1184 GNUNET_ResultCallback result_cb,
1189 GNUNET_PSYC_channel_history_replay_cancel (struct GNUNET_PSYC_Channel *channel,
1190 struct GNUNET_PSYC_HistoryRequest *hr);
1194 * Function called to inform a member about stored state values for a channel.
1196 * @param cls Closure.
1197 * @param name Name of the state variable. A NULL value indicates that there
1198 * are no more state variables to be returned.
1199 * @param value Value of the state variable.
1200 * @param value_size Number of bytes in @a value.
1203 (*GNUNET_PSYC_StateVarCallback) (void *cls,
1210 * State request handle.
1212 struct GNUNET_PSYC_StateRequest;
1216 * Retrieve the best matching channel state variable.
1218 * If the requested variable name is not present in the state, the nearest
1219 * less-specific name is matched; for example, requesting "_a_b" will match "_a"
1220 * if "_a_b" does not exist.
1225 * Full name of the requested variable.
1226 * The actual variable returned might have a shorter name.
1228 * Function called once when a matching state variable is found.
1229 * Not called if there's no matching state variable.
1231 * Function called after the operation finished.
1232 * (i.e. all state variables have been returned via @a state_cb)
1234 * Closure for the callbacks.
1236 struct GNUNET_PSYC_StateRequest *
1237 GNUNET_PSYC_channel_state_get (struct GNUNET_PSYC_Channel *channel,
1238 const char *full_name,
1239 GNUNET_PSYC_StateVarCallback var_cb,
1240 GNUNET_ResultCallback result_cb,
1245 * Return all channel state variables whose name matches a given prefix.
1247 * A name matches if it starts with the given @a name_prefix, thus requesting
1248 * the empty prefix ("") will match all values; requesting "_a_b" will also
1249 * return values stored under "_a_b_c".
1251 * The @a state_cb is invoked on all matching state variables asynchronously, as
1252 * the state is stored in and retrieved from the PSYCstore,
1256 * @param name_prefix
1257 * Prefix of the state variable name to match.
1259 * Function called once when a matching state variable is found.
1260 * Not called if there's no matching state variable.
1262 * Function called after the operation finished.
1263 * (i.e. all state variables have been returned via @a state_cb)
1265 * Closure for the callbacks.
1267 struct GNUNET_PSYC_StateRequest *
1268 GNUNET_PSYC_channel_state_get_prefix (struct GNUNET_PSYC_Channel *channel,
1269 const char *name_prefix,
1270 GNUNET_PSYC_StateVarCallback var_cb,
1271 GNUNET_ResultCallback result_cb,
1275 * Cancel a state request operation.
1278 * Handle for the operation to cancel.
1281 GNUNET_PSYC_channel_state_get_cancel (struct GNUNET_PSYC_StateRequest *sr);
1285 #if 0 /* keep Emacsens' auto-indent happy */
1292 /* ifndef GNUNET_PSYC_SERVICE_H */
1294 /* end of gnunet_psyc_service.h */