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- /*
- This file is part of GNUnet
- Copyright (C) 2013, 2014 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- or (at your option) any later version.
- GNUnet is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Affero General Public License for more details.
-
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @author Florian Dold
- * @author Christian Grothoff
- *
- * @file
- * Two-peer set operations
- *
- * @defgroup set Set service
- * Two-peer set operations
- *
- * @see [Documentation](https://gnunet.org/set-subsystem)
- *
- * @{
- */
- #ifndef GNUNET_SET_SERVICE_H
- #define GNUNET_SET_SERVICE_H
- #ifdef __cplusplus
- extern "C"
- {
- #if 0 /* keep Emacsens' auto-indent happy */
- }
- #endif
- #endif
- #include "gnunet_common.h"
- #include "gnunet_time_lib.h"
- #include "gnunet_configuration_lib.h"
- /**
- * Maximum size of a context message for set operation requests.
- */
- #define GNUNET_SET_CONTEXT_MESSAGE_MAX_SIZE ((1<<16) - 1024)
- /**
- * Opaque handle to a set.
- */
- struct GNUNET_SET_Handle;
- /**
- * Opaque handle to a set operation request from another peer.
- */
- struct GNUNET_SET_Request;
- /**
- * Opaque handle to a listen operation.
- */
- struct GNUNET_SET_ListenHandle;
- /**
- * Opaque handle to a set operation.
- */
- struct GNUNET_SET_OperationHandle;
- /**
- * The operation that a set set supports.
- */
- enum GNUNET_SET_OperationType
- {
- /**
- * A purely local set that does not support any operation.
- */
- GNUNET_SET_OPERATION_NONE,
- /**
- * Set intersection, only return elements that are in both sets.
- */
- GNUNET_SET_OPERATION_INTERSECTION,
- /**
- * Set union, return all elements that are in at least one of the sets.
- */
- GNUNET_SET_OPERATION_UNION
- };
- /**
- * Status for the result callback
- */
- enum GNUNET_SET_Status
- {
- /**
- * Everything went ok, we are transmitting an element of the
- * result (in set, or to be removed from set, depending on
- * the `enum GNUNET_SET_ResultMode`).
- *
- * Only applies to
- * #GNUNET_SET_RESULT_FULL,
- * #GNUNET_SET_RESULT_ADDED,
- * #GNUNET_SET_RESULT_REMOVED,
- */
- GNUNET_SET_STATUS_OK,
- /**
- * Element should be added to the result set
- * of the local peer, i.e. the local peer is
- * missing an element.
- *
- * Only applies to #GNUNET_SET_RESULT_SYMMETRIC
- */
- GNUNET_SET_STATUS_ADD_LOCAL,
- /**
- * Element should be added to the result set
- * of the remote peer, i.e. the remote peer is
- * missing an element.
- *
- * Only applies to #GNUNET_SET_RESULT_SYMMETRIC
- */
- GNUNET_SET_STATUS_ADD_REMOTE,
- /**
- * The other peer refused to to the operation with us,
- * or something went wrong.
- */
- GNUNET_SET_STATUS_FAILURE,
- /**
- * Success, all elements have been returned (but the other peer
- * might still be receiving some from us, so we are not done). Only
- * used during UNION operation.
- */
- GNUNET_SET_STATUS_HALF_DONE,
- /**
- * Success, all elements have been sent (and received).
- */
- GNUNET_SET_STATUS_DONE
- };
- /**
- * The way results are given to the client.
- */
- enum GNUNET_SET_ResultMode
- {
- /**
- * Client gets every element in the resulting set.
- *
- * Only supported for set intersection.
- */
- GNUNET_SET_RESULT_FULL,
- /**
- * Client gets notified of the required changes
- * for both the local and the remote set.
- *
- * Only supported for set
- */
- GNUNET_SET_RESULT_SYMMETRIC,
- /**
- * Client gets only elements that have been removed from the set.
- *
- * Only supported for set intersection.
- */
- GNUNET_SET_RESULT_REMOVED,
- /**
- * Client gets only elements that have been added to the set.
- *
- * Only supported for set union.
- */
- GNUNET_SET_RESULT_ADDED
- };
- /**
- * Element stored in a set.
- */
- struct GNUNET_SET_Element
- {
- /**
- * Number of bytes in the buffer pointed to by data.
- */
- uint16_t size;
- /**
- * Application-specific element type.
- */
- uint16_t element_type;
- /**
- * Actual data of the element
- */
- const void *data;
- };
- /**
- * Possible options to pass to a set operation.
- *
- * Used as tag for struct #GNUNET_SET_Option.
- */
- enum GNUNET_SET_OptionType
- {
- /**
- * List terminator.
- */
- GNUNET_SET_OPTION_END=0,
- /**
- * Fail set operations when the other peer shows weird behavior
- * that might by a Byzantine fault.
- *
- * For set union, 'v.num' is a lower bound on elements
- * that the other peer must have in common with us.
- */
- GNUNET_SET_OPTION_BYZANTINE=1,
- /**
- * Do not use the optimized set operation, but send full sets.
- * Might trigger Byzantine fault detection.
- */
- GNUNET_SET_OPTION_FORCE_FULL=2,
- /**
- * Only use optimized set operations, even though for this
- * particular set operation they might be much slower.
- * Might trigger Byzantine fault detection.
- */
- GNUNET_SET_OPTION_FORCE_DELTA=4,
- };
- /**
- * Option for set operations.
- */
- struct GNUNET_SET_Option
- {
- /**
- * Type of the option.
- */
- enum GNUNET_SET_OptionType type;
- /**
- * Value for the option, only used with some options.
- */
- union {
- uint64_t num;
- } v;
- };
- /**
- * Continuation used for some of the set operations
- *
- * @param cls closure
- */
- typedef void
- (*GNUNET_SET_Continuation) (void *cls);
- /**
- * Callback for set operation results. Called for each element
- * in the result set.
- *
- * @param cls closure
- * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
- * @param current_size current set size
- * @param status see `enum GNUNET_SET_Status`
- */
- typedef void
- (*GNUNET_SET_ResultIterator) (void *cls,
- const struct GNUNET_SET_Element *element,
- uint64_t current_size,
- enum GNUNET_SET_Status status);
- /**
- * Iterator for set elements.
- *
- * @param cls closure
- * @param element the current element, NULL if all elements have been
- * iterated over
- * @return #GNUNET_YES to continue iterating, #GNUNET_NO to stop.
- */
- typedef int
- (*GNUNET_SET_ElementIterator) (void *cls,
- const struct GNUNET_SET_Element *element);
- /**
- * Called when another peer wants to do a set operation with the
- * local peer. If a listen error occurs, the @a request is NULL.
- *
- * @param cls closure
- * @param other_peer the other peer
- * @param context_msg message with application specific information from
- * the other peer
- * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
- * to accept it, otherwise the request will be refused
- * Note that we can't just return value from the listen callback,
- * as it is also necessary to specify the set we want to do the
- * operation with, whith sometimes can be derived from the context
- * message. It's necessary to specify the timeout.
- */
- typedef void
- (*GNUNET_SET_ListenCallback) (void *cls,
- const struct GNUNET_PeerIdentity *other_peer,
- const struct GNUNET_MessageHeader *context_msg,
- struct GNUNET_SET_Request *request);
- typedef void
- (*GNUNET_SET_CopyReadyCallback) (void *cls,
- struct GNUNET_SET_Handle *copy);
- /**
- * Create an empty set, supporting the specified operation.
- *
- * @param cfg configuration to use for connecting to the
- * set service
- * @param op operation supported by the set
- * Note that the operation has to be specified
- * beforehand, as certain set operations need to maintain
- * data structures spefific to the operation
- * @return a handle to the set
- */
- struct GNUNET_SET_Handle *
- GNUNET_SET_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
- enum GNUNET_SET_OperationType op);
- /**
- * Add an element to the given set.
- * After the element has been added (in the sense of being
- * transmitted to the set service), @a cont will be called.
- * Calls to #GNUNET_SET_add_element can be queued
- *
- * @param set set to add element to
- * @param element element to add to the set
- * @param cont continuation called after the element has been added
- * @param cont_cls closure for @a cont
- * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
- * set is invalid (e.g. the set service crashed)
- */
- int
- GNUNET_SET_add_element (struct GNUNET_SET_Handle *set,
- const struct GNUNET_SET_Element *element,
- GNUNET_SET_Continuation cont,
- void *cont_cls);
- /**
- * Remove an element to the given set.
- * After the element has been removed (in the sense of the
- * request being transmitted to the set service), cont will be called.
- * Calls to remove_element can be queued
- *
- * @param set set to remove element from
- * @param element element to remove from the set
- * @param cont continuation called after the element has been removed
- * @param cont_cls closure for @a cont
- * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
- * set is invalid (e.g. the set service crashed)
- */
- int
- GNUNET_SET_remove_element (struct GNUNET_SET_Handle *set,
- const struct GNUNET_SET_Element *element,
- GNUNET_SET_Continuation cont,
- void *cont_cls);
- void
- GNUNET_SET_copy_lazy (struct GNUNET_SET_Handle *set,
- GNUNET_SET_CopyReadyCallback cb,
- void *cls);
- /**
- * Destroy the set handle, and free all associated resources.
- * Iterations must have completed (or be explicitly canceled)
- * before destroying the corresponding set. Operations may
- * still be pending when a set is destroyed.
- *
- * @param set set to destroy
- */
- void
- GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
- /**
- * Prepare a set operation to be evaluated with another peer.
- * The evaluation will not start until the client provides
- * a local set with GNUNET_SET_commit().
- *
- * @param other_peer peer with the other set
- * @param app_id hash for the application using the set
- * @param context_msg additional information for the request
- * @param result_mode specified how results will be returned,
- * see `enum GNUNET_SET_ResultMode`.
- * @param result_cb called on error or success
- * @param result_cls closure for @a result_cb
- * @return a handle to cancel the operation
- */
- struct GNUNET_SET_OperationHandle *
- GNUNET_SET_prepare (const struct GNUNET_PeerIdentity *other_peer,
- const struct GNUNET_HashCode *app_id,
- const struct GNUNET_MessageHeader *context_msg,
- enum GNUNET_SET_ResultMode result_mode,
- struct GNUNET_SET_Option options[],
- GNUNET_SET_ResultIterator result_cb,
- void *result_cls);
- /**
- * Wait for set operation requests for the given application ID.
- * If the connection to the set service is lost, the listener is
- * re-created transparently with exponential backoff.
- *
- * @param cfg configuration to use for connecting to
- * the set service
- * @param operation operation we want to listen for
- * @param app_id id of the application that handles set operation requests
- * @param listen_cb called for each incoming request matching the operation
- * and application id
- * @param listen_cls handle for @a listen_cb
- * @return a handle that can be used to cancel the listen operation
- */
- struct GNUNET_SET_ListenHandle *
- GNUNET_SET_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
- enum GNUNET_SET_OperationType op_type,
- const struct GNUNET_HashCode *app_id,
- GNUNET_SET_ListenCallback listen_cb,
- void *listen_cls);
- /**
- * Cancel the given listen operation. After calling cancel, the
- * listen callback for this listen handle will not be called again.
- * Note that cancelling a listen operation will automatically reject
- * all operations that have not yet been accepted.
- *
- * @param lh handle for the listen operation
- */
- void
- GNUNET_SET_listen_cancel (struct GNUNET_SET_ListenHandle *lh);
- /**
- * Accept a request we got via GNUNET_SET_listen(). Must be called during
- * GNUNET_SET_listen(), as the `struct GNUNET_SET_Request` becomes invalid
- * afterwards.
- * Call GNUNET_SET_commit() to provide the local set to use for the operation,
- * and to begin the exchange with the remote peer.
- *
- * @param request request to accept
- * @param result_mode specified how results will be returned,
- * see `enum GNUNET_SET_ResultMode`.
- * @param result_cb callback for the results
- * @param result_cls closure for @a result_cb
- * @return a handle to cancel the operation
- */
- struct GNUNET_SET_OperationHandle *
- GNUNET_SET_accept (struct GNUNET_SET_Request *request,
- enum GNUNET_SET_ResultMode result_mode,
- struct GNUNET_SET_Option options[],
- GNUNET_SET_ResultIterator result_cb,
- void *result_cls);
- /**
- * Commit a set to be used with a set operation.
- * This function is called once we have fully constructed
- * the set that we want to use for the operation. At this
- * time, the P2P protocol can then begin to exchange the
- * set information and call the result callback with the
- * result information.
- *
- * @param oh handle to the set operation
- * @param set the set to use for the operation
- * @return #GNUNET_OK on success, #GNUNET_SYSERR if the
- * set is invalid (e.g. the set service crashed)
- */
- int
- GNUNET_SET_commit (struct GNUNET_SET_OperationHandle *oh,
- struct GNUNET_SET_Handle *set);
- /**
- * Cancel the given set operation. May not be called after the
- * operation's `GNUNET_SET_ResultIterator` has been called with a
- * status that indicates error, timeout or done.
- *
- * @param oh set operation to cancel
- */
- void
- GNUNET_SET_operation_cancel (struct GNUNET_SET_OperationHandle *oh);
- /**
- * Iterate over all elements in the given set.
- * Note that this operation involves transferring every element of the set
- * from the service to the client, and is thus costly.
- * Only one iteration per set may be active at the same time.
- *
- * @param set the set to iterate over
- * @param iter the iterator to call for each element
- * @param iter_cls closure for @a iter
- * @return #GNUNET_YES if the iteration started successfuly,
- * #GNUNET_NO if another iteration was still active,
- * #GNUNET_SYSERR if the set is invalid (e.g. the server crashed, disconnected)
- */
- int
- GNUNET_SET_iterate (struct GNUNET_SET_Handle *set,
- GNUNET_SET_ElementIterator iter,
- void *iter_cls);
- /**
- * Stop iteration over all elements in the given set. Can only
- * be called before the iteration has "naturally" completed its
- * turn.
- *
- * @param set the set to stop iterating over
- */
- void
- GNUNET_SET_iterate_cancel (struct GNUNET_SET_Handle *set);
- /**
- * Create a copy of an element. The copy
- * must be GNUNET_free-d by the caller.
- *
- * @param element the element to copy
- * @return the copied element
- */
- struct GNUNET_SET_Element *
- GNUNET_SET_element_dup (const struct GNUNET_SET_Element *element);
- /**
- * Hash a set element.
- *
- * @param element the element that should be hashed
- * @param ret_hash a pointer to where the hash of @a element
- * should be stored
- */
- void
- GNUNET_SET_element_hash (const struct GNUNET_SET_Element *element,
- struct GNUNET_HashCode *ret_hash);
- #if 0 /* keep Emacsens' auto-indent happy */
- {
- #endif
- #ifdef __cplusplus
- }
- #endif
- #endif
- /** @} */ /* end of group */
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