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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 * The PSYC service adds this when delivering the message to local clients,
224 * not present on the multicast layer.
226 struct GNUNET_PSYC_MessageHeader
229 * Generic message header with size and type information.
231 struct GNUNET_MessageHeader header;
234 * Flags for this message fragment.
236 * @see enum GNUNET_PSYC_MessageFlags
238 uint32_t flags GNUNET_PACKED;
241 * Number of the message this message part belongs to.
242 * Monotonically increasing from 1.
244 uint64_t message_id GNUNET_PACKED;
247 * Byte offset of this @e fragment of the @e message.
248 * FIXME: use data_offset instead
250 uint64_t fragment_offset GNUNET_PACKED;
253 * Sending slave's public key.
254 * Not set if the message is from the master.
256 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
258 /* Followed by concatenated PSYC message parts:
259 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
265 * The method of a message.
267 struct GNUNET_PSYC_MessageMethod
270 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
272 struct GNUNET_MessageHeader header;
275 * OR'ed GNUNET_PSYC_MasterTransmitFlags
277 uint32_t flags GNUNET_PACKED;
280 * Number of message IDs since the last message that contained state
281 * operations. @see enum GNUNET_PSYC_StateDeltaValues
283 uint64_t state_delta GNUNET_PACKED;
285 /* Followed by NUL-terminated method name. */
290 * A modifier of a message.
292 struct GNUNET_PSYC_MessageModifier
295 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
297 struct GNUNET_MessageHeader header;
302 uint32_t value_size GNUNET_PACKED;
305 * Size of name, including NUL terminator.
307 uint16_t name_size GNUNET_PACKED;
310 * enum GNUNET_ENV_Operator
314 /* Followed by NUL-terminated name, then the value. */
318 struct GNUNET_PSYC_CountersResultMessage
321 * Type: GNUNET_MESSAGE_TYPE_PSYC_RESULT_COUNTERS
323 struct GNUNET_MessageHeader header;
326 * Status code for the operation.
328 uint32_t result_code GNUNET_PACKED;
331 * Last message ID sent to the channel.
333 uint64_t max_message_id GNUNET_PACKED;
338 * Join request sent to a PSYC master.
340 struct GNUNET_PSYC_JoinRequestMessage
343 * Type: GNUNET_MESSAGE_TYPE_PSYC_MASTER_JOIN_REQUEST
345 struct GNUNET_MessageHeader header;
347 * Public key of the joining slave.
349 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
351 /* Followed by struct GNUNET_MessageHeader join_request */
356 * Join decision sent in reply to a join request.
358 struct GNUNET_PSYC_JoinDecisionMessage
361 * Type: GNUNET_MESSAGE_TYPE_PSYC_JOIN_DECISION
363 struct GNUNET_MessageHeader header;
366 * #GNUNET_YES if the slave was admitted.
371 * Public key of the joining slave.
372 * Only set when the master is sending the decision,
373 * not set when a slave is receiving it.
375 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
377 /* Followed by struct GNUNET_MessageHeader join_response */
381 enum GNUNET_PSYC_HistoryReplayFlags
384 * Replay locally available messages.
386 GNUNET_PSYC_HISTORY_REPLAY_LOCAL = 0,
389 * Replay messages from remote peers if not found locally.
391 GNUNET_PSYC_HISTORY_REPLAY_REMOTE = 1,
395 struct GNUNET_PSYC_HistoryRequestMessage
398 * Type: GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_HISTORY_REPLAY
400 struct GNUNET_MessageHeader header;
403 * @see enum GNUNET_PSYC_HistoryReplayFlags
405 uint32_t flags GNUNET_PACKED;
408 * ID for this operation.
410 uint64_t op_id GNUNET_PACKED;
412 uint64_t start_message_id GNUNET_PACKED;
414 uint64_t end_message_id GNUNET_PACKED;
416 uint64_t message_limit GNUNET_PACKED;
418 /* Followed by NUL-terminated method name prefix. */
422 struct GNUNET_PSYC_StateRequestMessage
426 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET
427 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET_PREFIX
429 struct GNUNET_MessageHeader header;
431 uint32_t reserved GNUNET_PACKED;
434 * ID for this operation.
436 uint64_t op_id GNUNET_PACKED;
438 /* Followed by NUL-terminated name. */
442 /**** service -> library ****/
446 * Answer from service to client about last operation.
448 struct GNUNET_PSYC_OperationResultMessage
452 * - GNUNET_MESSAGE_TYPE_PSYC_RESULT_CODE
453 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_RESULT
455 struct GNUNET_MessageHeader header;
457 uint32_t reserved GNUNET_PACKED;
462 uint64_t op_id GNUNET_PACKED;
465 * Status code for the operation.
467 uint64_t result_code GNUNET_PACKED;
470 * - on error: NUL-terminated error message
471 * - on success: one of the following message types
473 * For a STATE_RESULT, one of:
474 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
475 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
476 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_END
480 GNUNET_NETWORK_STRUCT_END
483 #define GNUNET_PSYC_MODIFIER_MAX_PAYLOAD \
484 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
485 - sizeof (struct GNUNET_PSYC_MessageModifier)
487 #define GNUNET_PSYC_MOD_CONT_MAX_PAYLOAD \
488 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
489 - sizeof (struct GNUNET_MessageHeader)
491 #define GNUNET_PSYC_DATA_MAX_PAYLOAD \
492 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
493 - sizeof (struct GNUNET_MessageHeader)
497 * PSYC message part processing states.
499 enum GNUNET_PSYC_MessageState
501 GNUNET_PSYC_MESSAGE_STATE_START = 0,
502 GNUNET_PSYC_MESSAGE_STATE_HEADER = 1,
503 GNUNET_PSYC_MESSAGE_STATE_METHOD = 2,
504 GNUNET_PSYC_MESSAGE_STATE_MODIFIER = 3,
505 GNUNET_PSYC_MESSAGE_STATE_MOD_CONT = 4,
506 GNUNET_PSYC_MESSAGE_STATE_DATA = 5,
507 GNUNET_PSYC_MESSAGE_STATE_END = 6,
508 GNUNET_PSYC_MESSAGE_STATE_CANCEL = 7,
509 GNUNET_PSYC_MESSAGE_STATE_ERROR = 8,
514 * Handle that identifies a join request.
516 * Used to match calls to #GNUNET_PSYC_JoinCallback to the
517 * corresponding calls to GNUNET_PSYC_join_decision().
519 struct GNUNET_PSYC_JoinHandle;
523 * Method called from PSYC upon receiving a message.
525 * @param cls Closure.
526 * @param message_id Sequence number of the message.
527 * @param flags OR'ed GNUNET_PSYC_MessageFlags
528 * @param msg Message part, one of the following types:
531 (*GNUNET_PSYC_MessageCallback) (void *cls,
534 const struct GNUNET_PSYC_MessageHeader *msg);
538 * Method called from PSYC upon receiving part of a message.
543 * Public key of the slave sending the message.
544 * Only set for channel master.
546 * Sequence number of the message.
548 * OR'ed GNUNET_PSYC_MessageFlags
550 * Byte offset of data, only set if @a msg has a type
551 * #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
552 * @param msg Message part, one of the following types:
553 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_HEADER
554 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
555 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
556 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
557 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
558 * or NULL if an error occurred while receiving a message.
561 (*GNUNET_PSYC_MessagePartCallback) (void *cls,
562 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
565 uint64_t data_offset,
566 const struct GNUNET_MessageHeader *msg);
570 * Method called from PSYC upon receiving a join request.
575 * Public key of the slave requesting join.
577 * Join message sent along with the request.
579 * Join handle to use with GNUNET_PSYC_join_decision()
582 (*GNUNET_PSYC_JoinRequestCallback) (void *cls,
583 const struct GNUNET_PSYC_JoinRequestMessage *req,
584 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
585 const struct GNUNET_PSYC_Message *join_msg,
586 struct GNUNET_PSYC_JoinHandle *jh);
590 * Function to call with the decision made for a join request.
592 * Must be called once and only once in response to an invocation of the
593 * #GNUNET_PSYC_JoinCallback.
595 * @param jh Join request handle.
597 * #GNUNET_YES if the join is approved,
598 * #GNUNET_NO if it is disapproved,
599 * #GNUNET_SYSERR if we cannot answer the request.
600 * @param relay_count Number of relays given.
601 * @param relays Array of suggested peers that might be useful relays to use
602 * when joining the multicast group (essentially a list of peers that
603 * are already part of the multicast group and might thus be willing
604 * to help with routing). If empty, only this local peer (which must
605 * be the multicast origin) is a good candidate for building the
606 * multicast tree. Note that it is unnecessary to specify our own
607 * peer identity in this array.
608 * @param join_resp Application-dependent join response message to send along
611 * @return #GNUNET_OK on success,
612 * #GNUNET_SYSERR if @a join_resp is too large.
615 GNUNET_PSYC_join_decision (struct GNUNET_PSYC_JoinHandle *jh,
617 uint32_t relay_count,
618 const struct GNUNET_PeerIdentity *relays,
619 const struct GNUNET_PSYC_Message *join_resp);
623 * Handle for the master of a PSYC channel.
625 struct GNUNET_PSYC_Master;
629 * Function called after connected to the PSYC service
630 * and the channel master started.
632 * Also called when reconnected to the service
633 * after the connection closed unexpectedly.
638 * #GNUNET_YES if there were already messages sent to the channel,
639 * #GNUNET_NO if the message history is empty,
640 * #GNUNET_SYSERR on error.
641 * @param max_message_id
642 * Last message ID sent to the channel.
645 (*GNUNET_PSYC_MasterStartCallback) (void *cls, int result,
646 uint64_t max_message_id);
650 * Start a PSYC master channel.
652 * Will start a multicast group identified by the given ECC key. Messages
653 * received from group members will be given to the respective handler methods.
654 * If a new member wants to join a group, the "join" method handler will be
655 * invoked; the join handler must then generate a "join" message to approve the
656 * joining of the new member. The channel can also change group membership
657 * without explicit requests. Note that PSYC doesn't itself "understand" join
658 * or part messages, the respective methods must call other PSYC functions to
659 * inform PSYC about the meaning of the respective events.
661 * @param cfg Configuration to use (to connect to PSYC service).
662 * @param channel_key ECC key that will be used to sign messages for this
663 * PSYC session. The public key is used to identify the PSYC channel.
664 * Note that end-users will usually not use the private key directly, but
665 * rather look it up in GNS for places managed by other users, or select
666 * a file with the private key(s) when setting up their own channels
667 * FIXME: we'll likely want to use NOT the p521 curve here, but a cheaper
669 * @param policy Channel policy specifying join and history restrictions.
670 * Used to automate join decisions.
671 * @param master_start_cb Function to invoke after the channel master started.
672 * @param join_request_cb Function to invoke when a slave wants to join.
673 * @param message_cb Function to invoke on message parts sent to the channel
674 * and received from slaves
675 * @param cls Closure for @a method and @a join_cb.
677 * @return Handle for the channel master, NULL on error.
679 struct GNUNET_PSYC_Master *
680 GNUNET_PSYC_master_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
681 const struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key,
682 enum GNUNET_PSYC_Policy policy,
683 GNUNET_PSYC_MasterStartCallback master_start_cb,
684 GNUNET_PSYC_JoinRequestCallback join_request_cb,
685 GNUNET_PSYC_MessageCallback message_cb,
686 GNUNET_PSYC_MessagePartCallback message_part_cb,
691 * Function called to provide data for a transmission via PSYC.
693 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
694 * invalidates the respective transmission handle.
696 * @param cls Closure.
697 * @param[in,out] data_size Initially set to the number of bytes available in
698 * @a data, should be set to the number of bytes written to data.
699 * @param[out] data Where to write the body of the message to give to the
700 * method. The function must copy at most @a data_size bytes to @a data.
701 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
702 * #GNUNET_NO on success, if more data is to be transmitted later.
703 * Should be used if @a data_size was not big enough to take all the
704 * data. If 0 is returned in @a data_size the transmission is paused,
705 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
706 * #GNUNET_YES if this completes the transmission (all data supplied)
709 (*GNUNET_PSYC_TransmitNotifyData) (void *cls,
714 * Function called to provide a modifier for a transmission via PSYC.
716 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
717 * invalidates the respective transmission handle.
719 * @param cls Closure.
720 * @param[in,out] data_size Initially set to the number of bytes available in
721 * @a data, should be set to the number of bytes written to data.
722 * @param[out] data Where to write the modifier's name and value.
723 * The function must copy at most @a data_size bytes to @a data.
724 * When this callback is first called for a modifier, @a data should
725 * contain: "name\0value". If the whole value does not fit, subsequent
726 * calls to this function should write continuations of the value to
728 * @param[out] oper Where to write the operator of the modifier.
729 * Only needed during the first call to this callback at the beginning
730 * of the modifier. In case of subsequent calls asking for value
731 * continuations @a oper is set to #NULL.
732 * @param[out] full_value_size Where to write the full size of the value.
733 * Only needed during the first call to this callback at the beginning
734 * of the modifier. In case of subsequent calls asking for value
735 * continuations @a value_size is set to #NULL.
736 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
737 * #GNUNET_NO on success, if more data is to be transmitted later.
738 * Should be used if @a data_size was not big enough to take all the
739 * data for the modifier's value (the name must be always returned
740 * during the first call to this callback).
741 * If 0 is returned in @a data_size the transmission is paused,
742 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
743 * #GNUNET_YES if this completes the modifier (the whole value is supplied).
746 (*GNUNET_PSYC_TransmitNotifyModifier) (void *cls,
750 uint32_t *full_value_size);
753 * Flags for transmitting messages to a channel by the master.
755 enum GNUNET_PSYC_MasterTransmitFlags
757 GNUNET_PSYC_MASTER_TRANSMIT_NONE = 0,
760 * Whether this message should reset the channel state,
761 * i.e. remove all previously stored state variables.
764 GNUNET_PSYC_MASTER_TRANSMIT_STATE_RESET = 1 << 0,
767 * Whether this message contains any state modifiers.
769 GNUNET_PSYC_MASTER_TRANSMIT_STATE_MODIFY = 1 << 1,
772 * Add PSYC header variable with the hash of the current channel state.
774 GNUNET_PSYC_MASTER_TRANSMIT_STATE_HASH = 1 << 2,
777 * Whether we need to increment the group generation counter after
778 * transmitting this message.
780 GNUNET_PSYC_MASTER_TRANSMIT_INC_GROUP_GEN = 1 << 3
785 * Handle for a pending PSYC transmission operation.
787 struct GNUNET_PSYC_MasterTransmitHandle;
791 * Send a message to call a method to all members in the PSYC channel.
793 * @param master Handle to the PSYC channel.
794 * @param method_name Which method should be invoked.
795 * @param notify_mod Function to call to obtain modifiers.
796 * @param notify_data Function to call to obtain fragments of the data.
797 * @param notify_cls Closure for @a notify_mod and @a notify_data.
798 * @param flags Flags for the message being transmitted.
799 * @return Transmission handle, NULL on error (i.e. more than one request queued).
801 struct GNUNET_PSYC_MasterTransmitHandle *
802 GNUNET_PSYC_master_transmit (struct GNUNET_PSYC_Master *master,
803 const char *method_name,
804 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
805 GNUNET_PSYC_TransmitNotifyData notify_data,
807 enum GNUNET_PSYC_MasterTransmitFlags flags);
811 * Resume transmission to the channel.
813 * @param th Handle of the request that is being resumed.
816 GNUNET_PSYC_master_transmit_resume (struct GNUNET_PSYC_MasterTransmitHandle *th);
820 * Abort transmission request to channel.
822 * @param th Handle of the request that is being aborted.
825 GNUNET_PSYC_master_transmit_cancel (struct GNUNET_PSYC_MasterTransmitHandle *th);
829 * Stop a PSYC master channel.
832 * PSYC channel master to stop.
834 * Keep place active after last application disconnected.
836 * Function called after the master stopped
837 * and disconnected from the psyc service.
839 * Closure for @a part_cb.
842 GNUNET_PSYC_master_stop (struct GNUNET_PSYC_Master *master,
844 GNUNET_ContinuationCallback stop_cb,
849 * Handle for a PSYC channel slave.
851 struct GNUNET_PSYC_Slave;
855 * Function called after the slave connected to the PSYC service.
857 * Also called when reconnected to the service
858 * after the connection closed unexpectedly.
863 * #GNUNET_YES if there were already messages sent to the channel,
864 * #GNUNET_NO if the message history is empty,
865 * #GNUNET_SYSERR on error.
866 * @param max_message_id
867 * Last message ID sent to the channel.
870 (*GNUNET_PSYC_SlaveConnectCallback) (void *cls, int result,
871 uint64_t max_message_id);
875 * Method called to inform about the decision in response to a join request.
877 * If @a is_admitted is not #GNUNET_YES, then sending messages to the channel is
878 * not possible, but earlier history can be still queried.
880 * @param cls Closure.
881 * @param is_admitted #GNUNET_YES or #GNUNET_NO or #GNUNET_SYSERR
882 * @param join_msg Application-dependent join message from the origin.
885 (*GNUNET_PSYC_JoinDecisionCallback) (void *cls,
886 const struct GNUNET_PSYC_JoinDecisionMessage *dcsn,
888 const struct GNUNET_PSYC_Message *join_msg);
892 * Join a PSYC channel.
894 * The entity joining is always the local peer. The user must immediately use
895 * the GNUNET_PSYC_slave_transmit() functions to transmit a @e join_msg to the
896 * channel; if the join request succeeds, the channel state (and @e recent
897 * method calls) will be replayed to the joining member. There is no explicit
898 * notification on failure (as the channel may simply take days to approve,
899 * and disapproval is simply being ignored).
901 * @param cfg Configuration to use.
902 * @param channel_key ECC public key that identifies the channel we wish to join.
903 * @param slave_key ECC private-public key pair that identifies the slave, and
904 * used by multicast to sign the join request and subsequent unicast
905 * requests sent to the master.
906 * @param origin Peer identity of the origin.
907 * @param relay_count Number of peers in the @a relays array.
908 * @param relays Peer identities of members of the multicast group, which serve
909 * as relays and used to join the group at.
910 * @param message_cb Function to invoke on message parts received from the
911 * channel, typically at least contains method handlers for @e join and
913 * @param slave_connect_cb Function invoked once we have connected to the
915 * @param join_decision_cb Function invoked once we have received a join
917 * @param cls Closure for @a message_cb and @a slave_joined_cb.
918 * @param method_name Method name for the join request.
919 * @param env Environment containing transient variables for the request, or NULL.
920 * @param data Payload for the join message.
921 * @param data_size Number of bytes in @a data.
923 * @return Handle for the slave, NULL on error.
925 struct GNUNET_PSYC_Slave *
926 GNUNET_PSYC_slave_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
927 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
928 const struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key,
929 const struct GNUNET_PeerIdentity *origin,
930 uint32_t relay_count,
931 const struct GNUNET_PeerIdentity *relays,
932 GNUNET_PSYC_MessageCallback message_cb,
933 GNUNET_PSYC_MessagePartCallback message_part_cb,
934 GNUNET_PSYC_SlaveConnectCallback slave_connect_cb,
935 GNUNET_PSYC_JoinDecisionCallback join_decision_cb,
937 const struct GNUNET_PSYC_Message *join_msg);
941 * Part a PSYC channel.
943 * Will terminate the connection to the PSYC service. Polite clients should
944 * first explicitly send a part request (via GNUNET_PSYC_slave_transmit()).
949 * Keep place active after last application disconnected.
951 * Function called after the slave parted the channel
952 * and disconnected from the psyc service.
954 * Closure for @a part_cb.
957 GNUNET_PSYC_slave_part (struct GNUNET_PSYC_Slave *slave,
959 GNUNET_ContinuationCallback part_cb,
964 * Flags for transmitting messages to the channel master by a slave.
966 enum GNUNET_PSYC_SlaveTransmitFlags
968 GNUNET_PSYC_SLAVE_TRANSMIT_NONE = 0
973 * Handle for a pending PSYC transmission operation.
975 struct GNUNET_PSYC_SlaveTransmitHandle;
979 * Request a message to be sent to the channel master.
981 * @param slave Slave handle.
982 * @param method_name Which (PSYC) method should be invoked (on host).
983 * @param notify_mod Function to call to obtain modifiers.
984 * @param notify_data Function to call to obtain fragments of the data.
985 * @param notify_cls Closure for @a notify.
986 * @param flags Flags for the message being transmitted.
987 * @return Transmission handle, NULL on error (i.e. more than one request queued).
989 struct GNUNET_PSYC_SlaveTransmitHandle *
990 GNUNET_PSYC_slave_transmit (struct GNUNET_PSYC_Slave *slave,
991 const char *method_name,
992 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
993 GNUNET_PSYC_TransmitNotifyData notify_data,
995 enum GNUNET_PSYC_SlaveTransmitFlags flags);
999 * Resume transmission to the master.
1001 * @param th Handle of the request that is being resumed.
1004 GNUNET_PSYC_slave_transmit_resume (struct GNUNET_PSYC_SlaveTransmitHandle *th);
1008 * Abort transmission request to master.
1010 * @param th Handle of the request that is being aborted.
1013 GNUNET_PSYC_slave_transmit_cancel (struct GNUNET_PSYC_SlaveTransmitHandle *th);
1017 * Handle to access PSYC channel operations for both the master and slaves.
1019 struct GNUNET_PSYC_Channel;
1023 * Convert a channel @a master to a @e channel handle to access the @e channel
1026 * @param master Channel master handle.
1027 * @return Channel handle, valid for as long as @a master is valid.
1029 struct GNUNET_PSYC_Channel *
1030 GNUNET_PSYC_master_get_channel (struct GNUNET_PSYC_Master *master);
1034 * Convert @a slave to a @e channel handle to access the @e channel APIs.
1036 * @param slave Slave handle.
1037 * @return Channel handle, valid for as long as @a slave is valid.
1039 struct GNUNET_PSYC_Channel *
1040 GNUNET_PSYC_slave_get_channel (struct GNUNET_PSYC_Slave *slave);
1044 * Add a slave to the channel's membership list.
1046 * Note that this will NOT generate any PSYC traffic, it will merely update the
1047 * local database to modify how we react to <em>membership test</em> queries.
1048 * The channel master still needs to explicitly transmit a @e join message to
1049 * notify other channel members and they then also must still call this function
1050 * in their respective methods handling the @e join message. This way, how @e
1051 * join and @e part operations are exactly implemented is still up to the
1052 * application; for example, there might be a @e part_all method to kick out
1055 * Note that channel slaves are explicitly trusted to execute such methods
1056 * correctly; not doing so correctly will result in either denying other slaves
1057 * access or offering access to channel data to non-members.
1062 * Identity of channel slave to add.
1063 * @param announced_at
1064 * ID of the message that announced the membership change.
1065 * @param effective_since
1066 * Addition of slave is in effect since this message ID.
1068 * Function to call with the result of the operation.
1069 * The @e result_code argument is #GNUNET_OK on success, or
1070 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1071 * can contain an optional error message.
1073 * Closure for @a result_cb.
1076 GNUNET_PSYC_channel_slave_add (struct GNUNET_PSYC_Channel *channel,
1077 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
1078 uint64_t announced_at,
1079 uint64_t effective_since,
1080 GNUNET_ResultCallback result_cb,
1085 * Remove a slave from the channel's membership list.
1087 * Note that this will NOT generate any PSYC traffic, it will merely update the
1088 * local database to modify how we react to <em>membership test</em> queries.
1089 * The channel master still needs to explicitly transmit a @e part message to
1090 * notify other channel members and they then also must still call this function
1091 * in their respective methods handling the @e part message. This way, how
1092 * @e join and @e part operations are exactly implemented is still up to the
1093 * application; for example, there might be a @e part_all message to kick out
1096 * Note that channel members are explicitly trusted to perform these
1097 * operations correctly; not doing so correctly will result in either
1098 * denying members access or offering access to channel data to
1104 * Identity of channel slave to remove.
1105 * @param announced_at
1106 * ID of the message that announced the membership change.
1108 * Function to call with the result of the operation.
1109 * The @e result_code argument is #GNUNET_OK on success, or
1110 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1111 * can contain an optional error message.
1113 * Closure for @a result_cb.
1116 GNUNET_PSYC_channel_slave_remove (struct GNUNET_PSYC_Channel *channel,
1117 const struct GNUNET_CRYPTO_EcdsaPublicKey
1119 uint64_t announced_at,
1120 GNUNET_ResultCallback result_cb,
1125 * History request handle.
1127 struct GNUNET_PSYC_HistoryRequest;
1131 * Request to replay a part of the message history of the channel.
1133 * Historic messages (but NOT the state at the time) will be replayed (given to
1134 * the normal method handlers) if available and if access is permitted.
1137 * Which channel should be replayed?
1138 * @param start_message_id
1139 * Earliest interesting point in history.
1140 * @param end_message_id
1141 * Last (inclusive) interesting point in history.
1142 * @param method_prefix
1143 * Retrieve only messages with a matching method prefix.
1145 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1147 * Function to call when the requested history has been fully replayed.
1148 * Once this function has been called, the client must not call
1149 * GNUNET_PSYC_channel_history_replay_cancel() anymore.
1151 * Closure for the callbacks.
1153 * @return Handle to cancel history replay operation.
1155 struct GNUNET_PSYC_HistoryRequest *
1156 GNUNET_PSYC_channel_history_replay (struct GNUNET_PSYC_Channel *channel,
1157 uint64_t start_message_id,
1158 uint64_t end_message_id,
1159 const char *method_prefix,
1161 GNUNET_PSYC_MessageCallback message_cb,
1162 GNUNET_PSYC_MessagePartCallback message_part_cb,
1163 GNUNET_ResultCallback result_cb,
1168 * Request to replay the latest messages from the message history of the channel.
1170 * Historic messages (but NOT the state at the time) will be replayed (given to
1171 * the normal method handlers) if available and if access is permitted.
1174 * Which channel should be replayed?
1175 * @param message_limit
1176 * Maximum number of messages to replay.
1178 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1180 * Function to call when the requested history has been fully replayed
1181 * (counting message IDs might not suffice, as some messages might be
1182 * secret and thus the listener would not know the story is finished
1183 * without being told explicitly)o once this function has been called, the
1184 * client must not call GNUNET_PSYC_channel_history_replay_cancel() anymore.
1186 * Closure for the callbacks.
1188 * @return Handle to cancel history replay operation.
1190 struct GNUNET_PSYC_HistoryRequest *
1191 GNUNET_PSYC_channel_history_replay_latest (struct GNUNET_PSYC_Channel *channel,
1192 uint64_t message_limit,
1193 const char *method_prefix,
1195 GNUNET_PSYC_MessageCallback message_cb,
1196 GNUNET_PSYC_MessagePartCallback message_part_cb,
1197 GNUNET_ResultCallback result_cb,
1202 GNUNET_PSYC_channel_history_replay_cancel (struct GNUNET_PSYC_Channel *channel,
1203 struct GNUNET_PSYC_HistoryRequest *hr);
1207 * Function called to inform a member about stored state values for a channel.
1209 * If @a full_value_size > value_size then this function is called multiple
1210 * times until the whole value arrived.
1215 * Name of the state variable.
1216 * NULL if there are no more state variables to be returned.
1218 * Value of the state variable.
1220 * Number of bytes in @a value.
1221 * @param full_value_size
1222 * Number of bytes in the full value, including continuations.
1223 * Only set for the first part of a variable,
1224 * in case of a continuation it is 0.
1227 (*GNUNET_PSYC_StateVarCallback) (void *cls,
1228 const struct GNUNET_MessageHeader *mod,
1231 uint32_t value_size,
1232 uint32_t full_value_size);
1236 * State request handle.
1238 struct GNUNET_PSYC_StateRequest;
1242 * Retrieve the best matching channel state variable.
1244 * If the requested variable name is not present in the state, the nearest
1245 * less-specific name is matched; for example, requesting "_a_b" will match "_a"
1246 * if "_a_b" does not exist.
1251 * Full name of the requested variable.
1252 * The actual variable returned might have a shorter name.
1254 * Function called once when a matching state variable is found.
1255 * Not called if there's no matching state variable.
1257 * Function called after the operation finished.
1258 * (i.e. all state variables have been returned via @a state_cb)
1260 * Closure for the callbacks.
1262 struct GNUNET_PSYC_StateRequest *
1263 GNUNET_PSYC_channel_state_get (struct GNUNET_PSYC_Channel *channel,
1264 const char *full_name,
1265 GNUNET_PSYC_StateVarCallback var_cb,
1266 GNUNET_ResultCallback result_cb,
1271 * Return all channel state variables whose name matches a given prefix.
1273 * A name matches if it starts with the given @a name_prefix, thus requesting
1274 * the empty prefix ("") will match all values; requesting "_a_b" will also
1275 * return values stored under "_a_b_c".
1277 * The @a state_cb is invoked on all matching state variables asynchronously, as
1278 * the state is stored in and retrieved from the PSYCstore,
1282 * @param name_prefix
1283 * Prefix of the state variable name to match.
1285 * Function called once when a matching state variable is found.
1286 * Not called if there's no matching state variable.
1288 * Function called after the operation finished.
1289 * (i.e. all state variables have been returned via @a state_cb)
1291 * Closure for the callbacks.
1293 struct GNUNET_PSYC_StateRequest *
1294 GNUNET_PSYC_channel_state_get_prefix (struct GNUNET_PSYC_Channel *channel,
1295 const char *name_prefix,
1296 GNUNET_PSYC_StateVarCallback var_cb,
1297 GNUNET_ResultCallback result_cb,
1301 * Cancel a state request operation.
1304 * Handle for the operation to cancel.
1307 GNUNET_PSYC_channel_state_get_cancel (struct GNUNET_PSYC_StateRequest *sr);
1311 #if 0 /* keep Emacsens' auto-indent happy */
1318 /* ifndef GNUNET_PSYC_SERVICE_H */
1320 /* end of gnunet_psyc_service.h */