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3 Copyright (C) 2012, 2013 Christian Grothoff (and other contributing authors)
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22 * @author Gabor X Toth
23 * @author Christian Grothoff
28 * @defgroup psyc PSYC service
29 * Send/receive messages in PSYC channels and access the PSYC Store.
31 * Note that clients of this API are NOT expected to understand the PSYC message
32 * format, only the semantics! Parsing (and serializing) the PSYC stream format
33 * is done within the implementation of the libgnunetpsyc library, and this API
34 * deliberately exposes as little as possible of the actual data stream format
38 * - this API does not know about PSYC's "root" and "places";
39 * there is no 'root' in GNUnet-PSYC as we're decentralized;
40 * 'places' and 'persons' are combined within the same
41 * abstraction, that of a "channel". Channels are identified
42 * and accessed in this API using a public/private key.
43 * Higher-level applications should use NAMES within GNS
44 * to obtain public keys, and the distinction between
45 * 'places' and 'persons' can then be made with the help
46 * of the naming system (and/or conventions).
47 * Channels are (as in PSYC) organized into a hierarchy; each
48 * channel master (the one with the private key) is then
49 * the operator of the multicast group (its Origin in
50 * the terminology of the multicast API).
51 * - The API supports passing large amounts of data using
52 * 'streaming' for the argument passed to a method. State
53 * and variables must fit into memory and cannot be streamed
54 * (thus, no passing of 4 GB of data in a variable;
55 * once we implement this, we might want to create a
56 * @c \#define for the maximum size of a variable).
57 * - PSYC defines standard variables, methods, etc. This
58 * library deliberately abstracts over all of these; a
59 * higher-level API should combine the naming system (GNS)
60 * and standard methods (message, join, part, warn,
61 * fail, error) and variables (action, color, time,
62 * tag, etc.). However, this API does take over the
63 * routing variables, specifically 'context' (channel),
64 * and 'source'. We only kind-of support 'target', as
65 * the target is either everyone in the group or the
66 * origin, and never just a single member of the group;
67 * for such individual messages, an application needs to
68 * construct an 'inbox' channel where the master (only)
69 * receives messages (but never forwards; private responses
70 * would be transmitted by joining the senders 'inbox'
71 * channel -- or a inbox#bob subchannel). The
72 * goal for all of this is to keep the abstractions in this
73 * API minimal: interaction with multicast, try \& slice,
74 * state/variable/channel management. Higher-level
75 * operations belong elsewhere (so maybe this API should
76 * be called 'PSYC-low', whereas a higher-level API
77 * implementing defaults for standard methods and
78 * variables might be called 'PSYC-std' or 'PSYC-high'.
83 #ifndef GNUNET_PSYC_SERVICE_H
84 #define GNUNET_PSYC_SERVICE_H
89 #if 0 /* keep Emacsens' auto-indent happy */
94 #include "gnunet_util_lib.h"
95 #include "gnunet_env_lib.h"
96 #include "gnunet_multicast_service.h"
100 # define UINT64_MAX 0xffffffffffffffffULL
105 * Version number of GNUnet-PSYC API.
107 #define GNUNET_PSYC_VERSION 0x00000000
111 * Policy flags for a channel.
113 enum GNUNET_PSYC_ChannelFlags
116 * Admission must be confirmed by the master.
118 GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL = 1 << 0,
121 * Past messages are only available to slaves who were admitted at the time
122 * they were sent to the channel.
124 GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY = 1 << 1
129 * PSYC channel policies.
131 enum GNUNET_PSYC_Policy
134 * Anyone can join the channel, without announcing his presence;
135 * all messages are always public and can be distributed freely.
136 * Joins may be announced, but this is not required.
138 GNUNET_PSYC_CHANNEL_ANONYMOUS = 0,
141 * The master must approve membership to the channel, messages must only be
142 * distributed to current channel slaves. This includes the channel
143 * state as well as transient messages.
145 GNUNET_PSYC_CHANNEL_PRIVATE
146 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL
147 | GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY
151 * Anyone can freely join the channel (no approval required);
152 * however, messages must only be distributed to current channel
153 * slaves, so the master must still acknowledge that the slave
154 * joined before transient messages are delivered. As approval is
155 * guaranteed, the presistent channel state can be synchronized freely
156 * immediately, prior to master confirmation.
158 GNUNET_PSYC_CHANNEL_OPEN
159 = GNUNET_PSYC_CHANNEL_RESTRICTED_HISTORY,
162 * The master must approve joins to the channel, but past messages can be
163 * freely distributed to slaves.
165 GNUNET_PSYC_CHANNEL_CLOSED
166 = GNUNET_PSYC_CHANNEL_ADMISSION_CONTROL,
171 enum GNUNET_PSYC_MessageFlags
174 * Default / no flags.
176 GNUNET_PSYC_MESSAGE_DEFAULT = 0,
179 * Historic message, retrieved from PSYCstore.
181 GNUNET_PSYC_MESSAGE_HISTORIC = 1 << 0,
184 * Request from slave to master.
186 GNUNET_PSYC_MESSAGE_REQUEST = 1 << 1,
189 * Message can be delivered out of order.
191 GNUNET_PSYC_MESSAGE_ORDER_ANY = 1 << 2
196 * Values for the @a state_delta field of GNUNET_PSYC_MessageHeader.
198 enum GNUNET_PSYC_StateDeltaValues
200 GNUNET_PSYC_STATE_RESET = 0,
202 GNUNET_PSYC_STATE_NOT_MODIFIED = UINT64_MAX
206 GNUNET_NETWORK_STRUCT_BEGIN
211 * Used for single-fragment messages e.g. in a join request or response.
213 struct GNUNET_PSYC_Message
216 * Message header with size and type information.
218 struct GNUNET_MessageHeader header;
220 /* Followed by concatenated PSYC message parts:
221 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
227 * Header of a PSYC message.
229 * The PSYC service adds this when delivering the message to local clients,
230 * not present on the multicast layer.
232 struct GNUNET_PSYC_MessageHeader
235 * Generic message header with size and type information.
237 struct GNUNET_MessageHeader header;
240 * Flags for this message fragment.
242 * @see enum GNUNET_PSYC_MessageFlags
244 uint32_t flags GNUNET_PACKED;
247 * Number of the message this message part belongs to.
248 * Monotonically increasing from 1.
250 uint64_t message_id GNUNET_PACKED;
253 * Byte offset of this @e fragment of the @e message.
254 * FIXME: use data_offset instead
256 uint64_t fragment_offset GNUNET_PACKED;
259 * Sending slave's public key.
260 * Not set if the message is from the master.
262 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
264 /* Followed by concatenated PSYC message parts:
265 * messages with GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_* types
271 * The method of a message.
273 struct GNUNET_PSYC_MessageMethod
276 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
278 struct GNUNET_MessageHeader header;
281 * OR'ed GNUNET_PSYC_MasterTransmitFlags
283 uint32_t flags GNUNET_PACKED;
286 * Number of message IDs since the last message that contained state
287 * operations. @see enum GNUNET_PSYC_StateDeltaValues
289 uint64_t state_delta GNUNET_PACKED;
291 /* Followed by NUL-terminated method name. */
296 * A modifier of a message.
298 struct GNUNET_PSYC_MessageModifier
301 * Type: GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
303 struct GNUNET_MessageHeader header;
308 uint32_t value_size GNUNET_PACKED;
311 * Size of name, including NUL terminator.
313 uint16_t name_size GNUNET_PACKED;
316 * enum GNUNET_ENV_Operator
320 /* Followed by NUL-terminated name, then the value. */
324 struct GNUNET_PSYC_CountersResultMessage
327 * Type: GNUNET_MESSAGE_TYPE_PSYC_RESULT_COUNTERS
329 struct GNUNET_MessageHeader header;
332 * Status code for the operation.
334 uint32_t result_code GNUNET_PACKED;
337 * Last message ID sent to the channel.
339 uint64_t max_message_id GNUNET_PACKED;
344 * Join request sent to a PSYC master.
346 struct GNUNET_PSYC_JoinRequestMessage
349 * Type: GNUNET_MESSAGE_TYPE_PSYC_MASTER_JOIN_REQUEST
351 struct GNUNET_MessageHeader header;
353 * Public key of the joining slave.
355 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
357 /* Followed by struct GNUNET_MessageHeader join_request */
362 * Join decision sent in reply to a join request.
364 struct GNUNET_PSYC_JoinDecisionMessage
367 * Type: GNUNET_MESSAGE_TYPE_PSYC_JOIN_DECISION
369 struct GNUNET_MessageHeader header;
372 * #GNUNET_YES if the slave was admitted.
377 * Public key of the joining slave.
378 * Only set when the master is sending the decision,
379 * not set when a slave is receiving it.
381 struct GNUNET_CRYPTO_EcdsaPublicKey slave_key;
383 /* Followed by struct GNUNET_MessageHeader join_response */
387 enum GNUNET_PSYC_HistoryReplayFlags
390 * Replay locally available messages.
392 GNUNET_PSYC_HISTORY_REPLAY_LOCAL = 0,
395 * Replay messages from remote peers if not found locally.
397 GNUNET_PSYC_HISTORY_REPLAY_REMOTE = 1,
401 struct GNUNET_PSYC_HistoryRequestMessage
404 * Type: GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_HISTORY_REPLAY
406 struct GNUNET_MessageHeader header;
409 * @see enum GNUNET_PSYC_HistoryReplayFlags
411 uint32_t flags GNUNET_PACKED;
414 * ID for this operation.
416 uint64_t op_id GNUNET_PACKED;
418 uint64_t start_message_id GNUNET_PACKED;
420 uint64_t end_message_id GNUNET_PACKED;
422 uint64_t message_limit GNUNET_PACKED;
424 /* Followed by NUL-terminated method name prefix. */
428 struct GNUNET_PSYC_StateRequestMessage
432 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET
433 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_GET_PREFIX
435 struct GNUNET_MessageHeader header;
437 uint32_t reserved GNUNET_PACKED;
440 * ID for this operation.
442 uint64_t op_id GNUNET_PACKED;
444 /* Followed by NUL-terminated name. */
448 /**** service -> library ****/
452 * Answer from service to client about last operation.
454 struct GNUNET_PSYC_OperationResultMessage
458 * - GNUNET_MESSAGE_TYPE_PSYC_RESULT_CODE
459 * - GNUNET_MESSAGE_TYPE_PSYC_CHANNEL_STATE_RESULT
461 struct GNUNET_MessageHeader header;
463 uint32_t reserved GNUNET_PACKED;
468 uint64_t op_id GNUNET_PACKED;
471 * Status code for the operation.
473 uint64_t result_code GNUNET_PACKED;
476 * - on error: NUL-terminated error message
477 * - on success: one of the following message types
479 * For a STATE_RESULT, one of:
480 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
481 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
482 * - GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_END
486 GNUNET_NETWORK_STRUCT_END
489 #define GNUNET_PSYC_MODIFIER_MAX_PAYLOAD \
490 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
491 - sizeof (struct GNUNET_PSYC_MessageModifier)
493 #define GNUNET_PSYC_MOD_CONT_MAX_PAYLOAD \
494 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
495 - sizeof (struct GNUNET_MessageHeader)
497 #define GNUNET_PSYC_DATA_MAX_PAYLOAD \
498 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
499 - sizeof (struct GNUNET_MessageHeader)
503 * PSYC message part processing states.
505 enum GNUNET_PSYC_MessageState
507 GNUNET_PSYC_MESSAGE_STATE_START = 0,
508 GNUNET_PSYC_MESSAGE_STATE_HEADER = 1,
509 GNUNET_PSYC_MESSAGE_STATE_METHOD = 2,
510 GNUNET_PSYC_MESSAGE_STATE_MODIFIER = 3,
511 GNUNET_PSYC_MESSAGE_STATE_MOD_CONT = 4,
512 GNUNET_PSYC_MESSAGE_STATE_DATA = 5,
513 GNUNET_PSYC_MESSAGE_STATE_END = 6,
514 GNUNET_PSYC_MESSAGE_STATE_CANCEL = 7,
515 GNUNET_PSYC_MESSAGE_STATE_ERROR = 8,
520 * Handle that identifies a join request.
522 * Used to match calls to #GNUNET_PSYC_JoinCallback to the
523 * corresponding calls to GNUNET_PSYC_join_decision().
525 struct GNUNET_PSYC_JoinHandle;
529 * Method called from PSYC upon receiving a message.
531 * @param cls Closure.
532 * @param message_id Sequence number of the message.
533 * @param flags OR'ed GNUNET_PSYC_MessageFlags
534 * @param msg Message part, one of the following types:
537 (*GNUNET_PSYC_MessageCallback) (void *cls,
540 const struct GNUNET_PSYC_MessageHeader *msg);
544 * Method called from PSYC upon receiving part of a message.
549 * Public key of the slave sending the message.
550 * Only set for channel master.
552 * Sequence number of the message.
554 * OR'ed GNUNET_PSYC_MessageFlags
556 * Byte offset of data, only set if @a msg has a type
557 * #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
558 * @param msg Message part, one of the following types:
559 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_HEADER
560 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
561 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
562 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
563 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
564 * or NULL if an error occurred while receiving a message.
567 (*GNUNET_PSYC_MessagePartCallback) (void *cls,
568 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
571 uint64_t data_offset,
572 const struct GNUNET_MessageHeader *msg);
576 * Method called from PSYC upon receiving a join request.
581 * Public key of the slave requesting join.
583 * Join message sent along with the request.
585 * Join handle to use with GNUNET_PSYC_join_decision()
588 (*GNUNET_PSYC_JoinRequestCallback) (void *cls,
589 const struct GNUNET_PSYC_JoinRequestMessage *req,
590 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
591 const struct GNUNET_PSYC_Message *join_msg,
592 struct GNUNET_PSYC_JoinHandle *jh);
596 * Function to call with the decision made for a join request.
598 * Must be called once and only once in response to an invocation of the
599 * #GNUNET_PSYC_JoinCallback.
601 * @param jh Join request handle.
603 * #GNUNET_YES if the join is approved,
604 * #GNUNET_NO if it is disapproved,
605 * #GNUNET_SYSERR if we cannot answer the request.
606 * @param relay_count Number of relays given.
607 * @param relays Array of suggested peers that might be useful relays to use
608 * when joining the multicast group (essentially a list of peers that
609 * are already part of the multicast group and might thus be willing
610 * to help with routing). If empty, only this local peer (which must
611 * be the multicast origin) is a good candidate for building the
612 * multicast tree. Note that it is unnecessary to specify our own
613 * peer identity in this array.
614 * @param join_resp Application-dependent join response message to send along
617 * @return #GNUNET_OK on success,
618 * #GNUNET_SYSERR if @a join_resp is too large.
621 GNUNET_PSYC_join_decision (struct GNUNET_PSYC_JoinHandle *jh,
623 uint32_t relay_count,
624 const struct GNUNET_PeerIdentity *relays,
625 const struct GNUNET_PSYC_Message *join_resp);
629 * Handle for the master of a PSYC channel.
631 struct GNUNET_PSYC_Master;
635 * Function called after connected to the PSYC service
636 * and the channel master started.
638 * Also called when reconnected to the service
639 * after the connection closed unexpectedly.
644 * #GNUNET_YES if there were already messages sent to the channel,
645 * #GNUNET_NO if the message history is empty,
646 * #GNUNET_SYSERR on error.
647 * @param max_message_id
648 * Last message ID sent to the channel.
651 (*GNUNET_PSYC_MasterStartCallback) (void *cls, int result,
652 uint64_t max_message_id);
656 * Start a PSYC master channel.
658 * Will start a multicast group identified by the given ECC key. Messages
659 * received from group members will be given to the respective handler methods.
660 * If a new member wants to join a group, the "join" method handler will be
661 * invoked; the join handler must then generate a "join" message to approve the
662 * joining of the new member. The channel can also change group membership
663 * without explicit requests. Note that PSYC doesn't itself "understand" join
664 * or part messages, the respective methods must call other PSYC functions to
665 * inform PSYC about the meaning of the respective events.
667 * @param cfg Configuration to use (to connect to PSYC service).
668 * @param channel_key ECC key that will be used to sign messages for this
669 * PSYC session. The public key is used to identify the PSYC channel.
670 * Note that end-users will usually not use the private key directly, but
671 * rather look it up in GNS for places managed by other users, or select
672 * a file with the private key(s) when setting up their own channels
673 * FIXME: we'll likely want to use NOT the p521 curve here, but a cheaper
675 * @param policy Channel policy specifying join and history restrictions.
676 * Used to automate join decisions.
677 * @param master_start_cb Function to invoke after the channel master started.
678 * @param join_request_cb Function to invoke when a slave wants to join.
679 * @param message_cb Function to invoke on message parts sent to the channel
680 * and received from slaves
681 * @param cls Closure for @a method and @a join_cb.
683 * @return Handle for the channel master, NULL on error.
685 struct GNUNET_PSYC_Master *
686 GNUNET_PSYC_master_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
687 const struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key,
688 enum GNUNET_PSYC_Policy policy,
689 GNUNET_PSYC_MasterStartCallback master_start_cb,
690 GNUNET_PSYC_JoinRequestCallback join_request_cb,
691 GNUNET_PSYC_MessageCallback message_cb,
692 GNUNET_PSYC_MessagePartCallback message_part_cb,
697 * Function called to provide data for a transmission via PSYC.
699 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
700 * invalidates the respective transmission handle.
702 * @param cls Closure.
703 * @param[in,out] data_size Initially set to the number of bytes available in
704 * @a data, should be set to the number of bytes written to data.
705 * @param[out] data Where to write the body of the message to give to the
706 * method. The function must copy at most @a data_size bytes to @a data.
707 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
708 * #GNUNET_NO on success, if more data is to be transmitted later.
709 * Should be used if @a data_size was not big enough to take all the
710 * data. If 0 is returned in @a data_size the transmission is paused,
711 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
712 * #GNUNET_YES if this completes the transmission (all data supplied)
715 (*GNUNET_PSYC_TransmitNotifyData) (void *cls,
720 * Function called to provide a modifier for a transmission via PSYC.
722 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
723 * invalidates the respective transmission handle.
725 * @param cls Closure.
726 * @param[in,out] data_size Initially set to the number of bytes available in
727 * @a data, should be set to the number of bytes written to data.
728 * @param[out] data Where to write the modifier's name and value.
729 * The function must copy at most @a data_size bytes to @a data.
730 * When this callback is first called for a modifier, @a data should
731 * contain: "name\0value". If the whole value does not fit, subsequent
732 * calls to this function should write continuations of the value to
734 * @param[out] oper Where to write the operator of the modifier.
735 * Only needed during the first call to this callback at the beginning
736 * of the modifier. In case of subsequent calls asking for value
737 * continuations @a oper is set to #NULL.
738 * @param[out] full_value_size Where to write the full size of the value.
739 * Only needed during the first call to this callback at the beginning
740 * of the modifier. In case of subsequent calls asking for value
741 * continuations @a value_size is set to #NULL.
742 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
743 * #GNUNET_NO on success, if more data is to be transmitted later.
744 * Should be used if @a data_size was not big enough to take all the
745 * data for the modifier's value (the name must be always returned
746 * during the first call to this callback).
747 * If 0 is returned in @a data_size the transmission is paused,
748 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
749 * #GNUNET_YES if this completes the modifier (the whole value is supplied).
752 (*GNUNET_PSYC_TransmitNotifyModifier) (void *cls,
756 uint32_t *full_value_size);
759 * Flags for transmitting messages to a channel by the master.
761 enum GNUNET_PSYC_MasterTransmitFlags
763 GNUNET_PSYC_MASTER_TRANSMIT_NONE = 0,
766 * Whether this message should reset the channel state,
767 * i.e. remove all previously stored state variables.
770 GNUNET_PSYC_MASTER_TRANSMIT_STATE_RESET = 1 << 0,
773 * Whether this message contains any state modifiers.
775 GNUNET_PSYC_MASTER_TRANSMIT_STATE_MODIFY = 1 << 1,
778 * Add PSYC header variable with the hash of the current channel state.
780 GNUNET_PSYC_MASTER_TRANSMIT_STATE_HASH = 1 << 2,
783 * Whether we need to increment the group generation counter after
784 * transmitting this message.
786 GNUNET_PSYC_MASTER_TRANSMIT_INC_GROUP_GEN = 1 << 3
791 * Handle for a pending PSYC transmission operation.
793 struct GNUNET_PSYC_MasterTransmitHandle;
797 * Send a message to call a method to all members in the PSYC channel.
799 * @param master Handle to the PSYC channel.
800 * @param method_name Which method should be invoked.
801 * @param notify_mod Function to call to obtain modifiers.
802 * @param notify_data Function to call to obtain fragments of the data.
803 * @param notify_cls Closure for @a notify_mod and @a notify_data.
804 * @param flags Flags for the message being transmitted.
805 * @return Transmission handle, NULL on error (i.e. more than one request queued).
807 struct GNUNET_PSYC_MasterTransmitHandle *
808 GNUNET_PSYC_master_transmit (struct GNUNET_PSYC_Master *master,
809 const char *method_name,
810 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
811 GNUNET_PSYC_TransmitNotifyData notify_data,
813 enum GNUNET_PSYC_MasterTransmitFlags flags);
817 * Resume transmission to the channel.
819 * @param th Handle of the request that is being resumed.
822 GNUNET_PSYC_master_transmit_resume (struct GNUNET_PSYC_MasterTransmitHandle *th);
826 * Abort transmission request to channel.
828 * @param th Handle of the request that is being aborted.
831 GNUNET_PSYC_master_transmit_cancel (struct GNUNET_PSYC_MasterTransmitHandle *th);
835 * Stop a PSYC master channel.
838 * PSYC channel master to stop.
840 * Keep place active after last application disconnected.
842 * Function called after the master stopped
843 * and disconnected from the psyc service.
845 * Closure for @a part_cb.
848 GNUNET_PSYC_master_stop (struct GNUNET_PSYC_Master *master,
850 GNUNET_ContinuationCallback stop_cb,
855 * Handle for a PSYC channel slave.
857 struct GNUNET_PSYC_Slave;
861 * Function called after the slave connected to the PSYC service.
863 * Also called when reconnected to the service
864 * after the connection closed unexpectedly.
869 * #GNUNET_YES if there were already messages sent to the channel,
870 * #GNUNET_NO if the message history is empty,
871 * #GNUNET_SYSERR on error.
872 * @param max_message_id
873 * Last message ID sent to the channel.
876 (*GNUNET_PSYC_SlaveConnectCallback) (void *cls, int result,
877 uint64_t max_message_id);
881 * Method called to inform about the decision in response to a join request.
883 * If @a is_admitted is not #GNUNET_YES, then sending messages to the channel is
884 * not possible, but earlier history can be still queried.
886 * @param cls Closure.
887 * @param is_admitted #GNUNET_YES or #GNUNET_NO or #GNUNET_SYSERR
888 * @param join_msg Application-dependent join message from the origin.
891 (*GNUNET_PSYC_JoinDecisionCallback) (void *cls,
892 const struct GNUNET_PSYC_JoinDecisionMessage *dcsn,
894 const struct GNUNET_PSYC_Message *join_msg);
897 * Flags for GNUNET_PSYC_slave_join()
899 enum GNUNET_PSYC_SlaveJoinFlags
901 GNUNET_PSYC_SLAVE_JOIN_NONE = 0,
904 * Local join for history access, no network connection is established.
906 GNUNET_PSYC_SLAVE_JOIN_LOCAL = 1,
911 * Join a PSYC channel.
913 * The entity joining is always the local peer. The user must immediately use
914 * the GNUNET_PSYC_slave_transmit() functions to transmit a @e join_msg to the
915 * channel; if the join request succeeds, the channel state (and @e recent
916 * method calls) will be replayed to the joining member. There is no explicit
917 * notification on failure (as the channel may simply take days to approve,
918 * and disapproval is simply being ignored).
920 * @param cfg Configuration to use.
921 * @param channel_key ECC public key that identifies the channel we wish to join.
922 * @param slave_key ECC private-public key pair that identifies the slave, and
923 * used by multicast to sign the join request and subsequent unicast
924 * requests sent to the master.
925 * @param origin Peer identity of the origin.
926 * @param relay_count Number of peers in the @a relays array.
927 * @param relays Peer identities of members of the multicast group, which serve
928 * as relays and used to join the group at.
929 * @param message_cb Function to invoke on message parts received from the
930 * channel, typically at least contains method handlers for @e join and
932 * @param slave_connect_cb Function invoked once we have connected to the
934 * @param join_decision_cb Function invoked once we have received a join
936 * @param cls Closure for @a message_cb and @a slave_joined_cb.
937 * @param method_name Method name for the join request.
938 * @param env Environment containing transient variables for the request, or NULL.
939 * @param data Payload for the join message.
940 * @param data_size Number of bytes in @a data.
942 * @return Handle for the slave, NULL on error.
944 struct GNUNET_PSYC_Slave *
945 GNUNET_PSYC_slave_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
946 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
947 const struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key,
948 enum GNUNET_PSYC_SlaveJoinFlags flags,
949 const struct GNUNET_PeerIdentity *origin,
950 uint32_t relay_count,
951 const struct GNUNET_PeerIdentity *relays,
952 GNUNET_PSYC_MessageCallback message_cb,
953 GNUNET_PSYC_MessagePartCallback message_part_cb,
954 GNUNET_PSYC_SlaveConnectCallback slave_connect_cb,
955 GNUNET_PSYC_JoinDecisionCallback join_decision_cb,
957 const struct GNUNET_PSYC_Message *join_msg);
961 * Part a PSYC channel.
963 * Will terminate the connection to the PSYC service. Polite clients should
964 * first explicitly send a part request (via GNUNET_PSYC_slave_transmit()).
969 * Keep place active after last application disconnected.
971 * Function called after the slave parted the channel
972 * and disconnected from the psyc service.
974 * Closure for @a part_cb.
977 GNUNET_PSYC_slave_part (struct GNUNET_PSYC_Slave *slave,
979 GNUNET_ContinuationCallback part_cb,
984 * Flags for transmitting messages to the channel master by a slave.
986 enum GNUNET_PSYC_SlaveTransmitFlags
988 GNUNET_PSYC_SLAVE_TRANSMIT_NONE = 0
993 * Handle for a pending PSYC transmission operation.
995 struct GNUNET_PSYC_SlaveTransmitHandle;
999 * Request a message to be sent to the channel master.
1001 * @param slave Slave handle.
1002 * @param method_name Which (PSYC) method should be invoked (on host).
1003 * @param notify_mod Function to call to obtain modifiers.
1004 * @param notify_data Function to call to obtain fragments of the data.
1005 * @param notify_cls Closure for @a notify.
1006 * @param flags Flags for the message being transmitted.
1007 * @return Transmission handle, NULL on error (i.e. more than one request queued).
1009 struct GNUNET_PSYC_SlaveTransmitHandle *
1010 GNUNET_PSYC_slave_transmit (struct GNUNET_PSYC_Slave *slave,
1011 const char *method_name,
1012 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
1013 GNUNET_PSYC_TransmitNotifyData notify_data,
1015 enum GNUNET_PSYC_SlaveTransmitFlags flags);
1019 * Resume transmission to the master.
1021 * @param th Handle of the request that is being resumed.
1024 GNUNET_PSYC_slave_transmit_resume (struct GNUNET_PSYC_SlaveTransmitHandle *th);
1028 * Abort transmission request to master.
1030 * @param th Handle of the request that is being aborted.
1033 GNUNET_PSYC_slave_transmit_cancel (struct GNUNET_PSYC_SlaveTransmitHandle *th);
1037 * Handle to access PSYC channel operations for both the master and slaves.
1039 struct GNUNET_PSYC_Channel;
1043 * Convert a channel @a master to a @e channel handle to access the @e channel
1046 * @param master Channel master handle.
1047 * @return Channel handle, valid for as long as @a master is valid.
1049 struct GNUNET_PSYC_Channel *
1050 GNUNET_PSYC_master_get_channel (struct GNUNET_PSYC_Master *master);
1054 * Convert @a slave to a @e channel handle to access the @e channel APIs.
1056 * @param slave Slave handle.
1057 * @return Channel handle, valid for as long as @a slave is valid.
1059 struct GNUNET_PSYC_Channel *
1060 GNUNET_PSYC_slave_get_channel (struct GNUNET_PSYC_Slave *slave);
1064 * Add a slave to the channel's membership list.
1066 * Note that this will NOT generate any PSYC traffic, it will merely update the
1067 * local database to modify how we react to <em>membership test</em> queries.
1068 * The channel master still needs to explicitly transmit a @e join message to
1069 * notify other channel members and they then also must still call this function
1070 * in their respective methods handling the @e join message. This way, how @e
1071 * join and @e part operations are exactly implemented is still up to the
1072 * application; for example, there might be a @e part_all method to kick out
1075 * Note that channel slaves are explicitly trusted to execute such methods
1076 * correctly; not doing so correctly will result in either denying other slaves
1077 * access or offering access to channel data to non-members.
1082 * Identity of channel slave to add.
1083 * @param announced_at
1084 * ID of the message that announced the membership change.
1085 * @param effective_since
1086 * Addition of slave is in effect since this message ID.
1088 * Function to call with the result of the operation.
1089 * The @e result_code argument is #GNUNET_OK on success, or
1090 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1091 * can contain an optional error message.
1093 * Closure for @a result_cb.
1096 GNUNET_PSYC_channel_slave_add (struct GNUNET_PSYC_Channel *channel,
1097 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
1098 uint64_t announced_at,
1099 uint64_t effective_since,
1100 GNUNET_ResultCallback result_cb,
1105 * Remove a slave from the channel's membership list.
1107 * Note that this will NOT generate any PSYC traffic, it will merely update the
1108 * local database to modify how we react to <em>membership test</em> queries.
1109 * The channel master still needs to explicitly transmit a @e part message to
1110 * notify other channel members and they then also must still call this function
1111 * in their respective methods handling the @e part message. This way, how
1112 * @e join and @e part operations are exactly implemented is still up to the
1113 * application; for example, there might be a @e part_all message to kick out
1116 * Note that channel members are explicitly trusted to perform these
1117 * operations correctly; not doing so correctly will result in either
1118 * denying members access or offering access to channel data to
1124 * Identity of channel slave to remove.
1125 * @param announced_at
1126 * ID of the message that announced the membership change.
1128 * Function to call with the result of the operation.
1129 * The @e result_code argument is #GNUNET_OK on success, or
1130 * #GNUNET_SYSERR on error. In case of an error, the @e data argument
1131 * can contain an optional error message.
1133 * Closure for @a result_cb.
1136 GNUNET_PSYC_channel_slave_remove (struct GNUNET_PSYC_Channel *channel,
1137 const struct GNUNET_CRYPTO_EcdsaPublicKey
1139 uint64_t announced_at,
1140 GNUNET_ResultCallback result_cb,
1145 * History request handle.
1147 struct GNUNET_PSYC_HistoryRequest;
1151 * Request to replay a part of the message history of the channel.
1153 * Historic messages (but NOT the state at the time) will be replayed (given to
1154 * the normal method handlers) if available and if access is permitted.
1157 * Which channel should be replayed?
1158 * @param start_message_id
1159 * Earliest interesting point in history.
1160 * @param end_message_id
1161 * Last (inclusive) interesting point in history.
1162 * @param method_prefix
1163 * Retrieve only messages with a matching method prefix.
1165 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1167 * Function to call when the requested history has been fully replayed.
1168 * Once this function has been called, the client must not call
1169 * GNUNET_PSYC_channel_history_replay_cancel() anymore.
1171 * Closure for the callbacks.
1173 * @return Handle to cancel history replay operation.
1175 struct GNUNET_PSYC_HistoryRequest *
1176 GNUNET_PSYC_channel_history_replay (struct GNUNET_PSYC_Channel *channel,
1177 uint64_t start_message_id,
1178 uint64_t end_message_id,
1179 const char *method_prefix,
1181 GNUNET_PSYC_MessageCallback message_cb,
1182 GNUNET_PSYC_MessagePartCallback message_part_cb,
1183 GNUNET_ResultCallback result_cb,
1188 * Request to replay the latest messages from the message history of the channel.
1190 * Historic messages (but NOT the state at the time) will be replayed (given to
1191 * the normal method handlers) if available and if access is permitted.
1194 * Which channel should be replayed?
1195 * @param message_limit
1196 * Maximum number of messages to replay.
1198 * OR'ed enum GNUNET_PSYC_HistoryReplayFlags
1200 * Function to call when the requested history has been fully replayed
1201 * (counting message IDs might not suffice, as some messages might be
1202 * secret and thus the listener would not know the story is finished
1203 * without being told explicitly)o once this function has been called, the
1204 * client must not call GNUNET_PSYC_channel_history_replay_cancel() anymore.
1206 * Closure for the callbacks.
1208 * @return Handle to cancel history replay operation.
1210 struct GNUNET_PSYC_HistoryRequest *
1211 GNUNET_PSYC_channel_history_replay_latest (struct GNUNET_PSYC_Channel *channel,
1212 uint64_t message_limit,
1213 const char *method_prefix,
1215 GNUNET_PSYC_MessageCallback message_cb,
1216 GNUNET_PSYC_MessagePartCallback message_part_cb,
1217 GNUNET_ResultCallback result_cb,
1222 GNUNET_PSYC_channel_history_replay_cancel (struct GNUNET_PSYC_Channel *channel,
1223 struct GNUNET_PSYC_HistoryRequest *hr);
1227 * Function called to inform a member about stored state values for a channel.
1229 * If @a full_value_size > value_size then this function is called multiple
1230 * times until the whole value arrived.
1235 * Name of the state variable.
1236 * NULL if there are no more state variables to be returned.
1238 * Value of the state variable.
1240 * Number of bytes in @a value.
1241 * @param full_value_size
1242 * Number of bytes in the full value, including continuations.
1243 * Only set for the first part of a variable,
1244 * in case of a continuation it is 0.
1247 (*GNUNET_PSYC_StateVarCallback) (void *cls,
1248 const struct GNUNET_MessageHeader *mod,
1251 uint32_t value_size,
1252 uint32_t full_value_size);
1256 * State request handle.
1258 struct GNUNET_PSYC_StateRequest;
1262 * Retrieve the best matching channel state variable.
1264 * If the requested variable name is not present in the state, the nearest
1265 * less-specific name is matched; for example, requesting "_a_b" will match "_a"
1266 * if "_a_b" does not exist.
1271 * Full name of the requested variable.
1272 * The actual variable returned might have a shorter name.
1274 * Function called once when a matching state variable is found.
1275 * Not called if there's no matching state variable.
1277 * Function called after the operation finished.
1278 * (i.e. all state variables have been returned via @a state_cb)
1280 * Closure for the callbacks.
1282 struct GNUNET_PSYC_StateRequest *
1283 GNUNET_PSYC_channel_state_get (struct GNUNET_PSYC_Channel *channel,
1284 const char *full_name,
1285 GNUNET_PSYC_StateVarCallback var_cb,
1286 GNUNET_ResultCallback result_cb,
1291 * Return all channel state variables whose name matches a given prefix.
1293 * A name matches if it starts with the given @a name_prefix, thus requesting
1294 * the empty prefix ("") will match all values; requesting "_a_b" will also
1295 * return values stored under "_a_b_c".
1297 * The @a state_cb is invoked on all matching state variables asynchronously, as
1298 * the state is stored in and retrieved from the PSYCstore,
1302 * @param name_prefix
1303 * Prefix of the state variable name to match.
1305 * Function called once when a matching state variable is found.
1306 * Not called if there's no matching state variable.
1308 * Function called after the operation finished.
1309 * (i.e. all state variables have been returned via @a state_cb)
1311 * Closure for the callbacks.
1313 struct GNUNET_PSYC_StateRequest *
1314 GNUNET_PSYC_channel_state_get_prefix (struct GNUNET_PSYC_Channel *channel,
1315 const char *name_prefix,
1316 GNUNET_PSYC_StateVarCallback var_cb,
1317 GNUNET_ResultCallback result_cb,
1321 * Cancel a state request operation.
1324 * Handle for the operation to cancel.
1327 GNUNET_PSYC_channel_state_get_cancel (struct GNUNET_PSYC_StateRequest *sr);
1331 #if 0 /* keep Emacsens' auto-indent happy */
1338 /* ifndef GNUNET_PSYC_SERVICE_H */
1341 /** @} */ /* end of group */