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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 */
379 GNUNET_NETWORK_STRUCT_END
382 #define GNUNET_PSYC_MODIFIER_MAX_PAYLOAD \
383 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
384 - sizeof (struct GNUNET_PSYC_MessageModifier)
386 #define GNUNET_PSYC_MOD_CONT_MAX_PAYLOAD \
387 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
388 - sizeof (struct GNUNET_MessageHeader)
390 #define GNUNET_PSYC_DATA_MAX_PAYLOAD \
391 GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD \
392 - sizeof (struct GNUNET_MessageHeader)
396 * PSYC message part processing states.
398 enum GNUNET_PSYC_MessageState
400 GNUNET_PSYC_MESSAGE_STATE_START = 0,
401 GNUNET_PSYC_MESSAGE_STATE_HEADER = 1,
402 GNUNET_PSYC_MESSAGE_STATE_METHOD = 2,
403 GNUNET_PSYC_MESSAGE_STATE_MODIFIER = 3,
404 GNUNET_PSYC_MESSAGE_STATE_MOD_CONT = 4,
405 GNUNET_PSYC_MESSAGE_STATE_DATA = 5,
406 GNUNET_PSYC_MESSAGE_STATE_END = 6,
407 GNUNET_PSYC_MESSAGE_STATE_CANCEL = 7,
408 GNUNET_PSYC_MESSAGE_STATE_ERROR = 8,
413 * Handle that identifies a join request.
415 * Used to match calls to #GNUNET_PSYC_JoinCallback to the
416 * corresponding calls to GNUNET_PSYC_join_decision().
418 struct GNUNET_PSYC_JoinHandle;
422 * Method called from PSYC upon receiving a message.
424 * @param cls Closure.
425 * @param message_id Sequence number of the message.
426 * @param flags OR'ed GNUNET_PSYC_MessageFlags
427 * @param msg Message part, one of the following types:
430 (*GNUNET_PSYC_MessageCallback) (void *cls,
433 const struct GNUNET_PSYC_MessageHeader *msg);
437 * Method called from PSYC upon receiving part of a message.
439 * @param cls Closure.
440 * @param message_id Sequence number of the message.
441 * @param data_offset Byte offset of data, only set if @a msg has a type
442 * #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
443 * @param flags OR'ed GNUNET_PSYC_MessageFlags
444 * @param msg Message part, one of the following types:
445 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_HEADER
446 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_METHOD
447 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MODIFIER
448 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_MOD_CONT
449 * - #GNUNET_MESSAGE_TYPE_PSYC_MESSAGE_DATA
450 * or NULL if an error occurred while receiving a message.
453 (*GNUNET_PSYC_MessagePartCallback) (void *cls,
455 uint64_t data_offset,
457 const struct GNUNET_MessageHeader *msg);
461 * Method called from PSYC upon receiving a join request.
463 * @param cls Closure.
464 * @param slave_key Public key of the slave requesting join.
465 * @param join_msg Join message sent along with the request.
466 * @param jh Join handle to use with GNUNET_PSYC_join_decision()
469 (*GNUNET_PSYC_JoinRequestCallback) (void *cls,
470 const struct GNUNET_PSYC_JoinRequestMessage *req,
471 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
472 const struct GNUNET_PSYC_Message *join_msg,
473 struct GNUNET_PSYC_JoinHandle *jh);
477 * Function to call with the decision made for a join request.
479 * Must be called once and only once in response to an invocation of the
480 * #GNUNET_PSYC_JoinCallback.
482 * @param jh Join request handle.
484 * #GNUNET_YES if the join is approved,
485 * #GNUNET_NO if it is disapproved,
486 * #GNUNET_SYSERR if we cannot answer the request.
487 * @param relay_count Number of relays given.
488 * @param relays Array of suggested peers that might be useful relays to use
489 * when joining the multicast group (essentially a list of peers that
490 * are already part of the multicast group and might thus be willing
491 * to help with routing). If empty, only this local peer (which must
492 * be the multicast origin) is a good candidate for building the
493 * multicast tree. Note that it is unnecessary to specify our own
494 * peer identity in this array.
495 * @param join_resp Application-dependent join response message to send along
498 * @return #GNUNET_OK on success,
499 * #GNUNET_SYSERR if @a join_resp is too large.
502 GNUNET_PSYC_join_decision (struct GNUNET_PSYC_JoinHandle *jh,
504 uint32_t relay_count,
505 const struct GNUNET_PeerIdentity *relays,
506 const struct GNUNET_PSYC_Message *join_resp);
510 * Handle for the master of a PSYC channel.
512 struct GNUNET_PSYC_Master;
516 * Function called after connected to the PSYC service
517 * and the channel master started.
519 * Also called when reconnected to the service
520 * after the connection closed unexpectedly.
525 * #GNUNET_YES if there were already messages sent to the channel,
526 * #GNUNET_NO if the message history is empty,
527 * #GNUNET_SYSERR on error.
528 * @param max_message_id
529 * Last message ID sent to the channel.
532 (*GNUNET_PSYC_MasterStartCallback) (void *cls, int result,
533 uint64_t max_message_id);
537 * Start a PSYC master channel.
539 * Will start a multicast group identified by the given ECC key. Messages
540 * received from group members will be given to the respective handler methods.
541 * If a new member wants to join a group, the "join" method handler will be
542 * invoked; the join handler must then generate a "join" message to approve the
543 * joining of the new member. The channel can also change group membership
544 * without explicit requests. Note that PSYC doesn't itself "understand" join
545 * or part messages, the respective methods must call other PSYC functions to
546 * inform PSYC about the meaning of the respective events.
548 * @param cfg Configuration to use (to connect to PSYC service).
549 * @param channel_key ECC key that will be used to sign messages for this
550 * PSYC session. The public key is used to identify the PSYC channel.
551 * Note that end-users will usually not use the private key directly, but
552 * rather look it up in GNS for places managed by other users, or select
553 * a file with the private key(s) when setting up their own channels
554 * FIXME: we'll likely want to use NOT the p521 curve here, but a cheaper
556 * @param policy Channel policy specifying join and history restrictions.
557 * Used to automate join decisions.
558 * @param master_start_cb Function to invoke after the channel master started.
559 * @param join_request_cb Function to invoke when a slave wants to join.
560 * @param message_cb Function to invoke on message parts sent to the channel
561 * and received from slaves
562 * @param cls Closure for @a method and @a join_cb.
564 * @return Handle for the channel master, NULL on error.
566 struct GNUNET_PSYC_Master *
567 GNUNET_PSYC_master_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
568 const struct GNUNET_CRYPTO_EddsaPrivateKey *channel_key,
569 enum GNUNET_PSYC_Policy policy,
570 GNUNET_PSYC_MasterStartCallback master_start_cb,
571 GNUNET_PSYC_JoinRequestCallback join_request_cb,
572 GNUNET_PSYC_MessageCallback message_cb,
573 GNUNET_PSYC_MessagePartCallback message_part_cb,
578 * Function called to provide data for a transmission via PSYC.
580 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
581 * invalidates the respective transmission handle.
583 * @param cls Closure.
584 * @param[in,out] data_size Initially set to the number of bytes available in
585 * @a data, should be set to the number of bytes written to data.
586 * @param[out] data Where to write the body of the message to give to the
587 * method. The function must copy at most @a data_size bytes to @a data.
588 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
589 * #GNUNET_NO on success, if more data is to be transmitted later.
590 * Should be used if @a data_size was not big enough to take all the
591 * data. If 0 is returned in @a data_size the transmission is paused,
592 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
593 * #GNUNET_YES if this completes the transmission (all data supplied)
596 (*GNUNET_PSYC_TransmitNotifyData) (void *cls,
601 * Function called to provide a modifier for a transmission via PSYC.
603 * Note that returning #GNUNET_YES or #GNUNET_SYSERR (but not #GNUNET_NO)
604 * invalidates the respective transmission handle.
606 * @param cls Closure.
607 * @param[in,out] data_size Initially set to the number of bytes available in
608 * @a data, should be set to the number of bytes written to data.
609 * @param[out] data Where to write the modifier's name and value.
610 * The function must copy at most @a data_size bytes to @a data.
611 * When this callback is first called for a modifier, @a data should
612 * contain: "name\0value". If the whole value does not fit, subsequent
613 * calls to this function should write continuations of the value to
615 * @param[out] oper Where to write the operator of the modifier.
616 * Only needed during the first call to this callback at the beginning
617 * of the modifier. In case of subsequent calls asking for value
618 * continuations @a oper is set to #NULL.
619 * @param[out] full_value_size Where to write the full size of the value.
620 * Only needed during the first call to this callback at the beginning
621 * of the modifier. In case of subsequent calls asking for value
622 * continuations @a value_size is set to #NULL.
623 * @return #GNUNET_SYSERR on error (fatal, aborts transmission)
624 * #GNUNET_NO on success, if more data is to be transmitted later.
625 * Should be used if @a data_size was not big enough to take all the
626 * data for the modifier's value (the name must be always returned
627 * during the first call to this callback).
628 * If 0 is returned in @a data_size the transmission is paused,
629 * and can be resumed with GNUNET_PSYC_master_transmit_resume().
630 * #GNUNET_YES if this completes the modifier (the whole value is supplied).
633 (*GNUNET_PSYC_TransmitNotifyModifier) (void *cls,
637 uint32_t *full_value_size);
640 * Flags for transmitting messages to a channel by the master.
642 enum GNUNET_PSYC_MasterTransmitFlags
644 GNUNET_PSYC_MASTER_TRANSMIT_NONE = 0,
647 * Whether this message should reset the channel state,
648 * i.e. remove all previously stored state variables.
651 GNUNET_PSYC_MASTER_TRANSMIT_STATE_RESET = 1 << 0,
654 * Whether this message contains any state modifiers.
656 GNUNET_PSYC_MASTER_TRANSMIT_STATE_MODIFY = 1 << 1,
659 * Add PSYC header variable with the hash of the current channel state.
661 GNUNET_PSYC_MASTER_TRANSMIT_STATE_HASH = 1 << 2,
664 * Whether we need to increment the group generation counter after
665 * transmitting this message.
667 GNUNET_PSYC_MASTER_TRANSMIT_INC_GROUP_GEN = 1 << 3
672 * Handle for a pending PSYC transmission operation.
674 struct GNUNET_PSYC_MasterTransmitHandle;
678 * Send a message to call a method to all members in the PSYC channel.
680 * @param master Handle to the PSYC channel.
681 * @param method_name Which method should be invoked.
682 * @param notify_mod Function to call to obtain modifiers.
683 * @param notify_data Function to call to obtain fragments of the data.
684 * @param notify_cls Closure for @a notify_mod and @a notify_data.
685 * @param flags Flags for the message being transmitted.
686 * @return Transmission handle, NULL on error (i.e. more than one request queued).
688 struct GNUNET_PSYC_MasterTransmitHandle *
689 GNUNET_PSYC_master_transmit (struct GNUNET_PSYC_Master *master,
690 const char *method_name,
691 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
692 GNUNET_PSYC_TransmitNotifyData notify_data,
694 enum GNUNET_PSYC_MasterTransmitFlags flags);
698 * Resume transmission to the channel.
700 * @param th Handle of the request that is being resumed.
703 GNUNET_PSYC_master_transmit_resume (struct GNUNET_PSYC_MasterTransmitHandle *th);
707 * Abort transmission request to channel.
709 * @param th Handle of the request that is being aborted.
712 GNUNET_PSYC_master_transmit_cancel (struct GNUNET_PSYC_MasterTransmitHandle *th);
716 * Stop a PSYC master channel.
719 * PSYC channel master to stop.
721 * Keep place active after last application disconnected.
723 * Function called after the master stopped
724 * and disconnected from the psyc service.
726 * Closure for @a part_cb.
729 GNUNET_PSYC_master_stop (struct GNUNET_PSYC_Master *master,
731 GNUNET_ContinuationCallback stop_cb,
736 * Handle for a PSYC channel slave.
738 struct GNUNET_PSYC_Slave;
742 * Function called after the slave connected to the PSYC service.
744 * Also called when reconnected to the service
745 * after the connection closed unexpectedly.
750 * #GNUNET_YES if there were already messages sent to the channel,
751 * #GNUNET_NO if the message history is empty,
752 * #GNUNET_SYSERR on error.
753 * @param max_message_id
754 * Last message ID sent to the channel.
757 (*GNUNET_PSYC_SlaveConnectCallback) (void *cls, int result,
758 uint64_t max_message_id);
762 * Method called to inform about the decision in response to a join request.
764 * If @a is_admitted is not #GNUNET_YES, then sending messages to the channel is
765 * not possible, but earlier history can be still queried.
767 * @param cls Closure.
768 * @param is_admitted #GNUNET_YES or #GNUNET_NO or #GNUNET_SYSERR
769 * @param join_msg Application-dependent join message from the origin.
772 (*GNUNET_PSYC_JoinDecisionCallback) (void *cls,
773 const struct GNUNET_PSYC_JoinDecisionMessage *dcsn,
775 const struct GNUNET_PSYC_Message *join_msg);
779 * Join a PSYC channel.
781 * The entity joining is always the local peer. The user must immediately use
782 * the GNUNET_PSYC_slave_transmit() functions to transmit a @e join_msg to the
783 * channel; if the join request succeeds, the channel state (and @e recent
784 * method calls) will be replayed to the joining member. There is no explicit
785 * notification on failure (as the channel may simply take days to approve,
786 * and disapproval is simply being ignored).
788 * @param cfg Configuration to use.
789 * @param channel_key ECC public key that identifies the channel we wish to join.
790 * @param slave_key ECC private-public key pair that identifies the slave, and
791 * used by multicast to sign the join request and subsequent unicast
792 * requests sent to the master.
793 * @param origin Peer identity of the origin.
794 * @param relay_count Number of peers in the @a relays array.
795 * @param relays Peer identities of members of the multicast group, which serve
796 * as relays and used to join the group at.
797 * @param message_cb Function to invoke on message parts received from the
798 * channel, typically at least contains method handlers for @e join and
800 * @param slave_connect_cb Function invoked once we have connected to the
802 * @param join_decision_cb Function invoked once we have received a join
804 * @param cls Closure for @a message_cb and @a slave_joined_cb.
805 * @param method_name Method name for the join request.
806 * @param env Environment containing transient variables for the request, or NULL.
807 * @param data Payload for the join message.
808 * @param data_size Number of bytes in @a data.
810 * @return Handle for the slave, NULL on error.
812 struct GNUNET_PSYC_Slave *
813 GNUNET_PSYC_slave_join (const struct GNUNET_CONFIGURATION_Handle *cfg,
814 const struct GNUNET_CRYPTO_EddsaPublicKey *channel_key,
815 const struct GNUNET_CRYPTO_EcdsaPrivateKey *slave_key,
816 const struct GNUNET_PeerIdentity *origin,
817 uint32_t relay_count,
818 const struct GNUNET_PeerIdentity *relays,
819 GNUNET_PSYC_MessageCallback message_cb,
820 GNUNET_PSYC_MessagePartCallback message_part_cb,
821 GNUNET_PSYC_SlaveConnectCallback slave_connect_cb,
822 GNUNET_PSYC_JoinDecisionCallback join_decision_cb,
824 const struct GNUNET_PSYC_Message *join_msg);
828 * Part a PSYC channel.
830 * Will terminate the connection to the PSYC service. Polite clients should
831 * first explicitly send a part request (via GNUNET_PSYC_slave_transmit()).
836 * Keep place active after last application disconnected.
838 * Function called after the slave parted the channel
839 * and disconnected from the psyc service.
841 * Closure for @a part_cb.
844 GNUNET_PSYC_slave_part (struct GNUNET_PSYC_Slave *slave,
846 GNUNET_ContinuationCallback part_cb,
851 * Flags for transmitting messages to the channel master by a slave.
853 enum GNUNET_PSYC_SlaveTransmitFlags
855 GNUNET_PSYC_SLAVE_TRANSMIT_NONE = 0
860 * Handle for a pending PSYC transmission operation.
862 struct GNUNET_PSYC_SlaveTransmitHandle;
866 * Request a message to be sent to the channel master.
868 * @param slave Slave handle.
869 * @param method_name Which (PSYC) method should be invoked (on host).
870 * @param notify_mod Function to call to obtain modifiers.
871 * @param notify_data Function to call to obtain fragments of the data.
872 * @param notify_cls Closure for @a notify.
873 * @param flags Flags for the message being transmitted.
874 * @return Transmission handle, NULL on error (i.e. more than one request queued).
876 struct GNUNET_PSYC_SlaveTransmitHandle *
877 GNUNET_PSYC_slave_transmit (struct GNUNET_PSYC_Slave *slave,
878 const char *method_name,
879 GNUNET_PSYC_TransmitNotifyModifier notify_mod,
880 GNUNET_PSYC_TransmitNotifyData notify_data,
882 enum GNUNET_PSYC_SlaveTransmitFlags flags);
886 * Resume transmission to the master.
888 * @param th Handle of the request that is being resumed.
891 GNUNET_PSYC_slave_transmit_resume (struct GNUNET_PSYC_SlaveTransmitHandle *th);
895 * Abort transmission request to master.
897 * @param th Handle of the request that is being aborted.
900 GNUNET_PSYC_slave_transmit_cancel (struct GNUNET_PSYC_SlaveTransmitHandle *th);
904 * Handle to access PSYC channel operations for both the master and slaves.
906 struct GNUNET_PSYC_Channel;
910 * Function called with the result of an asynchronous operation.
915 * Result of the operation.
916 * Usually one of #GNUNET_OK, #GNUNET_YES, #GNUNET_NO, or #GNUNET_SYSERR.
921 (*GNUNET_PSYC_ResultCallback) (void *cls,
923 const char *err_msg);
927 * Convert a channel @a master to a @e channel handle to access the @e channel
930 * @param master Channel master handle.
931 * @return Channel handle, valid for as long as @a master is valid.
933 struct GNUNET_PSYC_Channel *
934 GNUNET_PSYC_master_get_channel (struct GNUNET_PSYC_Master *master);
938 * Convert @a slave to a @e channel handle to access the @e channel APIs.
940 * @param slave Slave handle.
941 * @return Channel handle, valid for as long as @a slave is valid.
943 struct GNUNET_PSYC_Channel *
944 GNUNET_PSYC_slave_get_channel (struct GNUNET_PSYC_Slave *slave);
948 * Add a slave to the channel's membership list.
950 * Note that this will NOT generate any PSYC traffic, it will merely update the
951 * local database to modify how we react to <em>membership test</em> queries.
952 * The channel master still needs to explicitly transmit a @e join message to
953 * notify other channel members and they then also must still call this function
954 * in their respective methods handling the @e join message. This way, how @e
955 * join and @e part operations are exactly implemented is still up to the
956 * application; for example, there might be a @e part_all method to kick out
959 * Note that channel slaves are explicitly trusted to execute such methods
960 * correctly; not doing so correctly will result in either denying other slaves
961 * access or offering access to channel data to non-members.
963 * @param channel Channel handle.
964 * @param slave_key Identity of channel slave to add.
965 * @param announced_at ID of the message that announced the membership change.
966 * @param effective_since Addition of slave is in effect since this message ID.
969 GNUNET_PSYC_channel_slave_add (struct GNUNET_PSYC_Channel *channel,
970 const struct GNUNET_CRYPTO_EcdsaPublicKey *slave_key,
971 uint64_t announced_at,
972 uint64_t effective_since,
973 GNUNET_PSYC_ResultCallback result_cb,
978 * Remove a slave from the channel's membership list.
980 * Note that this will NOT generate any PSYC traffic, it will merely update the
981 * local database to modify how we react to <em>membership test</em> queries.
982 * The channel master still needs to explicitly transmit a @e part message to
983 * notify other channel members and they then also must still call this function
984 * in their respective methods handling the @e part message. This way, how
985 * @e join and @e part operations are exactly implemented is still up to the
986 * application; for example, there might be a @e part_all message to kick out
989 * Note that channel members are explicitly trusted to perform these
990 * operations correctly; not doing so correctly will result in either
991 * denying members access or offering access to channel data to
994 * @param channel Channel handle.
995 * @param slave_key Identity of channel slave to remove.
996 * @param announced_at ID of the message that announced the membership change.
999 GNUNET_PSYC_channel_slave_remove (struct GNUNET_PSYC_Channel *channel,
1000 const struct GNUNET_CRYPTO_EcdsaPublicKey
1002 uint64_t announced_at,
1003 GNUNET_PSYC_ResultCallback result_cb,
1008 * Function called to inform a member about stored state values for a channel.
1010 * @param cls Closure.
1011 * @param name Name of the state variable. A NULL value indicates that there
1012 * are no more state variables to be returned.
1013 * @param value Value of the state variable.
1014 * @param value_size Number of bytes in @a value.
1017 (*GNUNET_PSYC_StateVarCallback) (void *cls,
1024 * Request to replay a part of the message history of the channel.
1026 * Historic messages (but NOT the state at the time) will be replayed (given to
1027 * the normal method handlers) if available and if access is permitted.
1030 * Which channel should be replayed?
1031 * @param start_message_id
1032 * Earliest interesting point in history.
1033 * @param end_message_id
1034 * Last (inclusive) interesting point in history.
1036 * Function to call when the requested history has been fully replayed
1037 * (counting message IDs might not suffice, as some messages might be
1038 * secret and thus the listener would not know the story is finished
1039 * without being told explicitly)o once this function has been called, the
1040 * client must not call GNUNET_PSYC_channel_history_replay_cancel() anymore.
1042 * Closure for the callbacks.
1044 * @return Handle to cancel history replay operation.
1047 GNUNET_PSYC_channel_history_replay (struct GNUNET_PSYC_Channel *channel,
1048 uint64_t start_message_id,
1049 uint64_t end_message_id,
1050 GNUNET_PSYC_ResultCallback finish_cb,
1055 * Request to replay the latest messages from the message history of the channel.
1057 * Historic messages (but NOT the state at the time) will be replayed (given to
1058 * the normal method handlers) if available and if access is permitted.
1061 * Which channel should be replayed?
1062 * @param message_limit
1063 * Maximum number of messages to replay.
1065 * Function to call when the requested history has been fully replayed
1066 * (counting message IDs might not suffice, as some messages might be
1067 * secret and thus the listener would not know the story is finished
1068 * without being told explicitly)o once this function has been called, the
1069 * client must not call GNUNET_PSYC_channel_history_replay_cancel() anymore.
1071 * Closure for the callbacks.
1073 * @return Handle to cancel history replay operation.
1076 GNUNET_PSYC_channel_history_replay_latest (struct GNUNET_PSYC_Channel *channel,
1077 uint64_t message_limit,
1078 GNUNET_PSYC_ResultCallback finish_cb,
1083 * Retrieve the best matching channel state variable.
1085 * If the requested variable name is not present in the state, the nearest
1086 * less-specific name is matched; for example, requesting "_a_b" will match "_a"
1087 * if "_a_b" does not exist.
1092 * Full name of the requested variable.
1093 * The actual variable returned might have a shorter name.
1095 * Function called once when a matching state variable is found.
1096 * Not called if there's no matching state variable.
1098 * Function called after the operation finished.
1099 * (i.e. all state variables have been returned via @a state_cb)
1101 * Closure for the callbacks.
1104 GNUNET_PSYC_channel_state_get (struct GNUNET_PSYC_Channel *channel,
1105 const char *full_name,
1106 GNUNET_PSYC_StateVarCallback var_cb,
1107 GNUNET_PSYC_ResultCallback result_cb,
1112 * Return all channel state variables whose name matches a given prefix.
1114 * A name matches if it starts with the given @a name_prefix, thus requesting
1115 * the empty prefix ("") will match all values; requesting "_a_b" will also
1116 * return values stored under "_a_b_c".
1118 * The @a state_cb is invoked on all matching state variables asynchronously, as
1119 * the state is stored in and retrieved from the PSYCstore,
1123 * @param name_prefix
1124 * Prefix of the state variable name to match.
1126 * Function called once when a matching state variable is found.
1127 * Not called if there's no matching state variable.
1129 * Function called after the operation finished.
1130 * (i.e. all state variables have been returned via @a state_cb)
1132 * Closure for the callbacks.
1135 GNUNET_PSYC_channel_state_get_prefix (struct GNUNET_PSYC_Channel *channel,
1136 const char *name_prefix,
1137 GNUNET_PSYC_StateVarCallback var_cb,
1138 GNUNET_PSYC_ResultCallback result_cb,
1142 #if 0 /* keep Emacsens' auto-indent happy */
1149 /* ifndef GNUNET_PSYC_SERVICE_H */
1151 /* end of gnunet_psyc_service.h */