-// FIXME: copyright, etc.
+/*
+ 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_Operation
+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.
+ * 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,
+
/**
- * There was a timeout.
+ * 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_TIMEOUT,
- /*
- * The other peer refused to to the operation with us
+ 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_REFUSED
+ 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
};
-// FIXME: comment
+
+
+/**
+ * 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 type;
+ uint16_t element_type;
+
/**
* Actual data of the element
*/
- void *data;
+ 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
* @return a handle to the set
*/
struct GNUNET_SET_Handle *
-GNUNET_SET_create (enum GNUNET_SET_Operation op);
+GNUNET_SET_create (const struct GNUNET_CONFIGURATION_Handle *cfg,
+ enum GNUNET_SET_OperationType op);
-// FIXME: comment
-void
+/**
+ * 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);
-// FIXME: comment
-void
+/**
+ * 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);
-// FIXME: comment
-struct GNUNET_SET_Handle *
-GNUNET_SET_clone (struct GNUNET_SET_Handle *set);
-
-
-// FIXME: comment
void
-GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
-
+GNUNET_SET_copy_lazy (struct GNUNET_SET_Handle *set,
+ GNUNET_SET_CopyReadyCallback cb,
+ void *cls);
/**
- * Callback for set operation results. Called for each element
- * in the result set.
-// FIXME: might want a way to just get the 'additional/removd' elements
+ * 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 cls closure
- * @param element element, or NULL to indicate that all elements
- * have been passed to the callback
- * Only valid if (status==GNUNET_SET_STATUS_OK) holds.
- * @param status see enum GNUNET_SET_Status
+ * @param set set to destroy
*/
-typedef void
-(*GNUNET_SET_ResultIterator) (void *cls,
- struct GNUNET_SET_Element *element,
- enum GNUNET_SET_ResultStatus status);
+void
+GNUNET_SET_destroy (struct GNUNET_SET_Handle *set);
/**
- * Evaluate a set operation with our set and the set of another peer.
+ * 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 result_cb
+ * @param result_cls closure for @a result_cb
* @return a handle to cancel the operation
*/
struct GNUNET_SET_OperationHandle *
-GNUNET_SET_evaluate (const struct GNUNET_PeerIdentity *other_peer,
- const struct GNUNET_HashCode *app_id,
- const struct GNUNET_MessageHeader *context_msg,
- struct GNUNET_TIME_Relative timeout,
- GNUNET_SET_ResultIterator result_cb,
- void *result_cls);
+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);
/**
- * Called when another peer wants to do a set operation with the
- * local peer
+ * 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 other_peer the other peer
- * @param context_msg message with application specific information from
- * the other peer
- * @param request request from the other peer, use GNUNET_SET_accept
- * to accept it, otherwise the request will be refused
- * Note that we don't use a return value here, 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.
- * Also 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);
-
-
-/**
- * Wait for set operation requests for the given application id
- *
+ * @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 listen_cb
+ * @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 (enum GNUNET_SET_Operation operation,
+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);
-
-// FIXME: comment
+/**
+ * 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
+ * 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 set set used for the requested operation
- * @param timeout timeout for the set operation
+ * @param result_mode specified how results will be returned,
+ * see `enum GNUNET_SET_ResultMode`.
* @param result_cb callback for the results
- * @param cls closure for result_cb
+ * @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,
- struct GNUNET_SET_Handle *set,
- struct GNUNET_TIME_Relative timeout,
+ enum GNUNET_SET_ResultMode result_mode,
+ struct GNUNET_SET_Option options[],
GNUNET_SET_ResultIterator result_cb,
- void *cls)
+ void *result_cls);
-// FIXME: comment
+/**
+ * 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 *op);
-
+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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