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- /*
- This file is part of GNUnet.
- Copyright (C) 2012-2016 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
- * General-purpose message queue
- *
- * @defgroup mq MQ library
- * General-purpose message queue
- *
- * @see [Documentation](https://gnunet.org/message-queue-api)
- *
- * @{
- */
- #ifndef GNUNET_MQ_LIB_H
- #define GNUNET_MQ_LIB_H
- #include "gnunet_scheduler_lib.h"
- /**
- * Allocate an envelope, with extra space allocated after the space needed
- * by the message struct.
- * The allocated message will already have the type and size field set.
- *
- * @param mvar variable to store the allocated message in;
- * must have a header field;
- * can be NULL
- * @param esize extra space to allocate after the message
- * @param type type of the message
- * @return the MQ message
- */
- #define GNUNET_MQ_msg_extra(mvar, esize, type) \
- GNUNET_MQ_msg_ (((struct GNUNET_MessageHeader **) &(mvar)), \
- (esize) + sizeof *(mvar), \
- (type))
- /**
- * Allocate a GNUNET_MQ_Envelope.
- * The contained message will already have the type and size field set.
- *
- * @param mvar variable to store the allocated message in;
- * must have a header field;
- * can be NULL
- * @param type type of the message
- * @return the allocated envelope
- */
- #define GNUNET_MQ_msg(mvar, type) GNUNET_MQ_msg_extra (mvar, 0, type)
- /**
- * Allocate a GNUNET_MQ_Envelope, where the message only consists of a header.
- * The allocated message will already have the type and size field set.
- *
- * @param type type of the message
- */
- #define GNUNET_MQ_msg_header(type) \
- GNUNET_MQ_msg_ (NULL, sizeof(struct GNUNET_MessageHeader), type)
- /**
- * Allocate a GNUNET_MQ_Envelope, where the message only consists of a header and extra space.
- * The allocated message will already have the type and size field set.
- *
- * @param mh pointer that will changed to point at to the allocated message header
- * @param esize extra space to allocate after the message header
- * @param type type of the message
- */
- #define GNUNET_MQ_msg_header_extra(mh, esize, type) \
- GNUNET_MQ_msg_ (&mh, (esize) + sizeof(struct GNUNET_MessageHeader), type)
- /**
- * Allocate a GNUNET_MQ_Envelope, and append a payload message after the given
- * message struct.
- *
- * @param mvar pointer to a message struct, will be changed to point at the newly allocated message,
- * whose size is 'sizeof(*mvar) + ntohs (mh->size)'
- * @param type message type of the allocated message, has no effect on the nested message
- * @param mh message to nest
- * @return a newly allocated 'struct GNUNET_MQ_Envelope *'
- */
- #define GNUNET_MQ_msg_nested_mh(mvar, type, mh) \
- ({ \
- struct GNUNET_MQ_Envelope *_ev; \
- _ev = GNUNET_MQ_msg_nested_mh_ ((struct GNUNET_MessageHeader **) &(mvar), \
- sizeof(*(mvar)), \
- (type), \
- (mh)); \
- (void) (mvar)->header; /* type check */ \
- _ev; \
- })
- /**
- * Return a pointer to the message at the end of the given message.
- *
- * @param var pointer to a message struct, the type of the expression determines the base size,
- * the space after the base size is the nested message
- * @return a 'struct GNUNET_MessageHeader *' that points at the nested message of the given message,
- * or NULL if the given message in @a var does not have any space after the message struct
- */
- #define GNUNET_MQ_extract_nested_mh(var) \
- GNUNET_MQ_extract_nested_mh_ ((struct GNUNET_MessageHeader *) (var), \
- sizeof(*(var)))
- /**
- * Implementation of the #GNUNET_MQ_extract_nexted_mh macro.
- *
- * @param mh message header to extract nested message header from
- * @param base_size size of the message before the nested message's header appears
- * @return pointer to the nested message, does not copy the message
- * OR NULL in case of a malformed message.
- */
- const struct GNUNET_MessageHeader *
- GNUNET_MQ_extract_nested_mh_ (const struct GNUNET_MessageHeader *mh,
- uint16_t base_size);
- /**
- * Opaque handle to an envelope.
- */
- struct GNUNET_MQ_Envelope;
- /**
- * Obtain message contained in envelope.
- *
- * @param env the envelope
- * @return message contained in the envelope
- */
- const struct GNUNET_MessageHeader *
- GNUNET_MQ_env_get_msg (const struct GNUNET_MQ_Envelope *env);
- /**
- * Return next envelope in queue.
- *
- * @param env a queued envelope
- * @return next one, or NULL
- */
- const struct GNUNET_MQ_Envelope *
- GNUNET_MQ_env_next (const struct GNUNET_MQ_Envelope *env);
- /**
- * Implementation of the #GNUNET_MQ_msg_nested_mh macro.
- *
- * @param mhp pointer to the message header pointer that will be changed to allocate at
- * the newly allocated space for the message.
- * @param base_size size of the data before the nested message
- * @param type type of the message in the envelope
- * @param nested_mh the message to append to the message after base_size
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_msg_nested_mh_ (struct GNUNET_MessageHeader **mhp,
- uint16_t base_size,
- uint16_t type,
- const struct GNUNET_MessageHeader *nested_mh);
- /**
- * Opaque handle to a message queue.
- */
- struct GNUNET_MQ_Handle;
- /**
- * Error codes for the queue.
- */
- enum GNUNET_MQ_Error
- {
- /**
- * Failed to read message from the network.
- * FIXME: Likely not properly distinguished
- * from TIMEOUT case in the code!
- */
- GNUNET_MQ_ERROR_READ = 1,
- /**
- * FIXME: document!
- */
- GNUNET_MQ_ERROR_WRITE = 2,
- /**
- * FIXME: document!
- */
- GNUNET_MQ_ERROR_TIMEOUT = 4,
- /**
- * We received a message that was malformed and thus
- * could not be passed to its handler.
- */
- GNUNET_MQ_ERROR_MALFORMED = 8,
- /**
- * We received a message for which we have no matching
- * handler.
- */
- GNUNET_MQ_ERROR_NO_MATCH = 16
- };
- /**
- * Per envelope preferences and priorities.
- */
- enum GNUNET_MQ_PriorityPreferences
- {
- /**
- * Lowest priority, i.e. background traffic (i.e. NSE, FS).
- * This is the default!
- */
- GNUNET_MQ_PRIO_BACKGROUND = 0,
- /**
- * Best-effort traffic (i.e. CADET relay, DHT)
- */
- GNUNET_MQ_PRIO_BEST_EFFORT = 1,
- /**
- * Urgent traffic (local peer, i.e. Conversation).
- */
- GNUNET_MQ_PRIO_URGENT = 2,
- /**
- * Highest priority, control traffic (i.e. CORE/CADET KX).
- */
- GNUNET_MQ_PRIO_CRITICAL_CONTROL = 3,
- /**
- * Bit mask to apply to extract the priority bits.
- */
- GNUNET_MQ_PRIORITY_MASK = 3,
- /**
- * Flag to indicate that unreliable delivery is acceptable. This
- * means TRANSPORT will not attempt to receive an
- * acknowledgment. CORE will just pass this flag through. CADET
- * will use unreliable delivery if this flag is set.
- *
- * Note that even without this flag, messages may be lost by
- * TRANSPORT and CORE.
- *
- * Thus, how "strong" the semantics of reliable delivery are depends
- * on the layer!
- */
- GNUNET_MQ_PREF_UNRELIABLE = 16,
- /**
- * Flag to indicate that low latency is important. This flag must
- * generally not be used in combination with
- * #GNUNET_MQ_PREF_CORKING_ALLOWED as it would be a contradiction.
- * When this flags is set, the envelope may skip forward in the
- * queue (depending on priority) and also TRANSPORT should attempt
- * to pick a communicator with particularly low latency.
- */
- GNUNET_MQ_PREF_LOW_LATENCY = 32,
- /**
- * Flag to indicate that CORKing is acceptable. This allows the
- * receiver to delay transmission in hope of combining this message
- * with other messages into a larger transmission with less
- * per-message overhead.
- */
- GNUNET_MQ_PREF_CORK_ALLOWED = 64,
- /**
- * Flag to indicate that high bandwidth is desired. This flag
- * indicates that the method chosen for transmission should focus on
- * overall goodput. It rarely makes sense to combine this flag with
- * #GNUNET_MQ_PREF_LOW_LATENCY.
- */
- GNUNET_MQ_PREF_GOODPUT = 128,
- /**
- * Flag to indicate that out-of-order delivery is OK.
- */
- GNUNET_MQ_PREF_OUT_OF_ORDER = 256,
- };
- /**
- * Called when a message has been received.
- *
- * @param cls closure
- * @param msg the received message
- */
- typedef void (*GNUNET_MQ_MessageCallback) (
- void *cls,
- const struct GNUNET_MessageHeader *msg);
- /**
- * Called when a message needs to be validated.
- *
- * @param cls closure
- * @param msg the received message
- * @return #GNUNET_OK if the message is well-formed,
- * #GNUNET_SYSERR if not
- */
- typedef int (*GNUNET_MQ_MessageValidationCallback) (
- void *cls,
- const struct GNUNET_MessageHeader *msg);
- /**
- * Signature of functions implementing the
- * sending functionality of a message queue.
- *
- * @param mq the message queue
- * @param msg the message to send
- * @param impl_state state of the implementation
- */
- typedef void (*GNUNET_MQ_SendImpl) (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MessageHeader *msg,
- void *impl_state);
- /**
- * Signature of functions implementing the
- * destruction of a message queue.
- * Implementations must not free @a mq, but should
- * take care of @a impl_state.
- *
- * @param mq the message queue to destroy
- * @param impl_state state of the implementation
- */
- typedef void (*GNUNET_MQ_DestroyImpl) (struct GNUNET_MQ_Handle *mq,
- void *impl_state);
- /**
- * Implementation function that cancels the currently sent message.
- *
- * @param mq message queue
- * @param impl_state state specific to the implementation
- */
- typedef void (*GNUNET_MQ_CancelImpl) (struct GNUNET_MQ_Handle *mq,
- void *impl_state);
- /**
- * Generic error handler, called with the appropriate
- * error code and the same closure specified at the creation of
- * the message queue.
- * Not every message queue implementation supports an error handler.
- *
- * @param cls closure
- * @param error error code
- */
- typedef void (*GNUNET_MQ_ErrorHandler) (void *cls, enum GNUNET_MQ_Error error);
- /**
- * Insert @a env into the envelope DLL starting at @a env_head
- * Note that @a env must not be in any MQ while this function
- * is used with DLLs defined outside of the MQ module. This
- * is just in case some application needs to also manage a
- * FIFO of envelopes independent of MQ itself and wants to
- * re-use the pointers internal to @a env. Use with caution.
- *
- * @param[in|out] env_head of envelope DLL
- * @param[in|out] env_tail tail of envelope DLL
- * @param[in|out] env element to insert at the tail
- */
- void
- GNUNET_MQ_dll_insert_head (struct GNUNET_MQ_Envelope **env_head,
- struct GNUNET_MQ_Envelope **env_tail,
- struct GNUNET_MQ_Envelope *env);
- /**
- * Insert @a env into the envelope DLL starting at @a env_head
- * Note that @a env must not be in any MQ while this function
- * is used with DLLs defined outside of the MQ module. This
- * is just in case some application needs to also manage a
- * FIFO of envelopes independent of MQ itself and wants to
- * re-use the pointers internal to @a env. Use with caution.
- *
- * @param[in|out] env_head of envelope DLL
- * @param[in|out] env_tail tail of envelope DLL
- * @param[in|out] env element to insert at the tail
- */
- void
- GNUNET_MQ_dll_insert_tail (struct GNUNET_MQ_Envelope **env_head,
- struct GNUNET_MQ_Envelope **env_tail,
- struct GNUNET_MQ_Envelope *env);
- /**
- * Remove @a env from the envelope DLL starting at @a env_head.
- * Note that @a env must not be in any MQ while this function
- * is used with DLLs defined outside of the MQ module. This
- * is just in case some application needs to also manage a
- * FIFO of envelopes independent of MQ itself and wants to
- * re-use the pointers internal to @a env. Use with caution.
- *
- * @param[in|out] env_head of envelope DLL
- * @param[in|out] env_tail tail of envelope DLL
- * @param[in|out] env element to remove from the DLL
- */
- void
- GNUNET_MQ_dll_remove (struct GNUNET_MQ_Envelope **env_head,
- struct GNUNET_MQ_Envelope **env_tail,
- struct GNUNET_MQ_Envelope *env);
- /**
- * Copy an array of handlers.
- *
- * Useful if the array has been delared in local memory and needs to be
- * persisted for future use.
- *
- * @param handlers Array of handlers to be copied.
- * @return A newly allocated array of handlers.
- * Needs to be freed with #GNUNET_free.
- */
- struct GNUNET_MQ_MessageHandler *
- GNUNET_MQ_copy_handlers (const struct GNUNET_MQ_MessageHandler *handlers);
- /**
- * Copy an array of handlers, appending AGPL handler.
- *
- * Useful if the array has been delared in local memory and needs to be
- * persisted for future use.
- *
- * @param handlers Array of handlers to be copied. Can be NULL (nothing done).
- * @param agpl_handler function to call for AGPL handling
- * @param agpl_cls closure for @a agpl_handler
- * @return A newly allocated array of handlers.
- * Needs to be freed with #GNUNET_free.
- */
- struct GNUNET_MQ_MessageHandler *
- GNUNET_MQ_copy_handlers2 (const struct GNUNET_MQ_MessageHandler *handlers,
- GNUNET_MQ_MessageCallback agpl_handler,
- void *agpl_cls);
- /**
- * Count the handlers in a handler array.
- *
- * @param handlers Array of handlers to be counted.
- * @return The number of handlers in the array.
- */
- unsigned int
- GNUNET_MQ_count_handlers (const struct GNUNET_MQ_MessageHandler *handlers);
- /**
- * Message handler for a specific message type.
- */
- struct GNUNET_MQ_MessageHandler
- {
- /**
- * Callback to validate a message of the specified @e type.
- * The closure given to @e mv will be this struct (not @e ctx).
- * Using NULL means only size-validation using
- * @e expected_size. In this case, @e expected_size must
- * be non-zero.
- */
- GNUNET_MQ_MessageValidationCallback mv;
- /**
- * Callback, called every time a new message of
- * the specified @e type has been receied.
- * The closure given to @e mv will be this struct (not @e ctx).
- */
- GNUNET_MQ_MessageCallback cb;
- /**
- * Closure for @e mv and @e cb.
- */
- void *cls;
- /**
- * Type of the message this handler covers, in host byte order.
- */
- uint16_t type;
- /**
- * Expected size of messages of this type. Minimum size of the
- * message if @e mv is non-NULL. Messages of the given type will be
- * discarded (and the connection closed with an error reported to
- * the application) if they do not have the right size.
- */
- uint16_t expected_size;
- };
- /**
- * End-marker for the handlers array
- */
- #define GNUNET_MQ_handler_end() \
- { \
- NULL, NULL, NULL, 0, 0 \
- }
- /**
- * Defines a static function @a name which takes as a single argument
- * a message handler for fixed-sized messages of type @a code and with
- * a message type argument of @a str. Given such an argument, the
- * function @name will return a `struct GNUNET_MQ_MessageHandler`
- * for the given message type.
- *
- * The macro is to be used as follows:
- * <code>
- * struct GNUNET_MessageTest { ... }; // must be fixed size
- * static void
- * handle_test_message (void *cls,
- * const struct GNUNET_MessageTest *msg)
- * { ... }
- *
- * struct GNUNET_MQ_MessageHandler handlers[] = {
- * GNUNET_MQ_hd_fixed_size(test_message,
- * GNUNET_MESSAGE_TYPE_TEST,
- * struct GNUNET_MessageTest,
- * "context"),
- * GNUNET_MQ_handler_end()
- * };
- *
- * @param name unique basename for the functions
- * @param code message type constant
- * @param str type of the message (a struct)
- * @param ctx context for the callbacks
- */
- #define GNUNET_MQ_hd_fixed_size(name, code, str, ctx) \
- ({ \
- void (*_cb)(void *cls, const str * msg) = &handle_ ## name; \
- ((struct GNUNET_MQ_MessageHandler){ NULL, \
- (GNUNET_MQ_MessageCallback) _cb, \
- (ctx), \
- (code), \
- sizeof(str) }); \
- })
- /**
- * Defines a static function @a name which takes two arguments and a
- * context-pointer for validating and handling variable-sized messages
- * of type @a code and with a message type argument of @a str. Given
- * such arguments, the function @name will return a `struct
- * GNUNET_MQ_MessageHandler` for the given message type.
- *
- * The macro is to be used as follows:
- * <code>
- * struct GNUNET_MessageTest { ... }; // can be variable size
- * static int
- * check_test (void *cls,
- * const struct GNUNET_MessageTest *msg)
- * {
- * const char *ctx = cls;
- * GNUNET_assert (0 == strcmp ("context", ctx));
- * // ...
- * }
- * static void
- * handle_test (void *cls,
- * const struct GNUNET_MessageTest *msg)
- * {
- * const char *ctx = cls;
- * GNUNET_assert (0 == strcmp ("context", ctx));
- * // ...
- * }
- *
- * struct GNUNET_MQ_MessageHandler handlers[] = {
- * GNUNET_MQ_hd_var_size(test_message,
- * GNUNET_MESSAGE_TYPE_TEST,
- * struct GNUNET_MessageTest,
- * "context"),
- * GNUNET_MQ_handler_end()
- * };
- *
- * @param name unique basename for the functions
- * @param code message type constant
- * @param str type of the message (a struct)
- * @param ctx context for the callbacks
- */
- #define GNUNET_MQ_hd_var_size(name, code, str, ctx) \
- __extension__ ({ \
- int (*_mv)(void *cls, const str * msg) = &check_ ## name; \
- void (*_cb)(void *cls, const str * msg) = &handle_ ## name; \
- ((struct GNUNET_MQ_MessageHandler){ (GNUNET_MQ_MessageValidationCallback) \
- _mv, \
- (GNUNET_MQ_MessageCallback) _cb, \
- (ctx), \
- (code), \
- sizeof(str) }); \
- })
- /**
- * Insert code for a "check_" function that verifies that
- * a given variable-length message received over the network
- * is followed by a 0-terminated string. If the message @a m
- * is not followed by a 0-terminated string, an error is logged
- * and the function is returned with #GNUNET_NO.
- *
- * @param an IPC message with proper type to determine
- * the size, starting with a `struct GNUNET_MessageHeader`
- */
- #define GNUNET_MQ_check_zero_termination(m) \
- { \
- const char *str = (const char *) &m[1]; \
- const struct GNUNET_MessageHeader *hdr = \
- (const struct GNUNET_MessageHeader *) m; \
- uint16_t slen = ntohs (hdr->size) - sizeof(*m); \
- if ((0 == slen) || (memchr (str, 0, slen) != &str[slen - 1])) \
- { \
- GNUNET_break (0); \
- return GNUNET_NO; \
- } \
- }
- /**
- * Insert code for a "check_" function that verifies that
- * a given variable-length message received over the network
- * is followed by another variable-length message that fits
- * exactly with the given size. If the message @a m
- * is not followed by another `struct GNUNET_MessageHeader`
- * with a size that adds up to the total size, an error is logged
- * and the function is returned with #GNUNET_NO.
- *
- * @param an IPC message with proper type to determine
- * the size, starting with a `struct GNUNET_MessageHeader`
- */
- #define GNUNET_MQ_check_boxed_message(m) \
- { \
- const struct GNUNET_MessageHeader *inbox = \
- (const struct GNUNET_MessageHeader *) &m[1]; \
- const struct GNUNET_MessageHeader *hdr = \
- (const struct GNUNET_MessageHeader *) m; \
- uint16_t slen = ntohs (hdr->size) - sizeof(*m); \
- if ((slen < sizeof(struct GNUNET_MessageHeader)) || \
- (slen != ntohs (inbox->size))) \
- { \
- GNUNET_break (0); \
- return GNUNET_NO; \
- } \
- }
- /**
- * Call the message message handler that was registered
- * for the type of the given message in the given @a handlers list.
- *
- * This function is indended to be used for the implementation
- * of message queues.
- *
- * @param handlers a set of handlers
- * @param mh message to dispatch
- * @return #GNUNET_OK on success, #GNUNET_NO if no handler matched,
- * #GNUNET_SYSERR if message was rejected by check function
- */
- int
- GNUNET_MQ_handle_message (const struct GNUNET_MQ_MessageHandler *handlers,
- const struct GNUNET_MessageHeader *mh);
- /**
- * Create a new envelope.
- *
- * @param mhp message header to store the allocated message header in, can be NULL
- * @param size size of the message to allocate
- * @param type type of the message, will be set in the allocated message
- * @return the allocated MQ message
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_msg_ (struct GNUNET_MessageHeader **mhp,
- uint16_t size,
- uint16_t type);
- /**
- * Create a new envelope by copying an existing message.
- *
- * @param hdr header of the message to copy
- * @return envelope containing @a hdr
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_msg_copy (const struct GNUNET_MessageHeader *hdr);
- /**
- * Discard the message queue message, free all
- * allocated resources. Must be called in the event
- * that a message is created but should not actually be sent.
- *
- * @param mqm the message to discard
- */
- void
- GNUNET_MQ_discard (struct GNUNET_MQ_Envelope *mqm);
- /**
- * Function to obtain the current envelope
- * from within #GNUNET_MQ_SendImpl implementations.
- *
- * @param mq message queue to interrogate
- * @return the current envelope
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_get_current_envelope (struct GNUNET_MQ_Handle *mq);
- /**
- * Function to copy an envelope. The envelope must not yet
- * be in any queue or have any options or callbacks set.
- *
- * @param env envelope to copy
- * @return copy of @a env
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_env_copy (struct GNUNET_MQ_Envelope *env);
- /**
- * Function to obtain the last envelope in the queue.
- *
- * @param mq message queue to interrogate
- * @return the last envelope in the queue
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_get_last_envelope (struct GNUNET_MQ_Handle *mq);
- /**
- * Set application-specific options for this envelope.
- * Overrides the options set for the queue with
- * #GNUNET_MQ_set_options() for this message only.
- *
- * @param env message to set options for
- * @param pp priority and preferences to set for @a env
- */
- void
- GNUNET_MQ_env_set_options (struct GNUNET_MQ_Envelope *env,
- enum GNUNET_MQ_PriorityPreferences pp);
- /**
- * Get performance preferences set for this envelope.
- *
- * @param env message to set options for
- * @return priority and preferences to use
- */
- enum GNUNET_MQ_PriorityPreferences
- GNUNET_MQ_env_get_options (struct GNUNET_MQ_Envelope *env);
- /**
- * Combine performance preferences set for different
- * envelopes that are being combined into one larger envelope.
- *
- * @param p1 one set of preferences
- * @param p2 second set of preferences
- * @return combined priority and preferences to use
- */
- enum GNUNET_MQ_PriorityPreferences
- GNUNET_MQ_env_combine_options (enum GNUNET_MQ_PriorityPreferences p1,
- enum GNUNET_MQ_PriorityPreferences p2);
- /**
- * Remove the first envelope that has not yet been sent from the message
- * queue and return it.
- *
- * @param mq queue to remove envelope from
- * @return NULL if queue is empty (or has no envelope that is not under transmission)
- */
- struct GNUNET_MQ_Envelope *
- GNUNET_MQ_unsent_head (struct GNUNET_MQ_Handle *mq);
- /**
- * Set application-specific options for this queue.
- *
- * @param mq message queue to set options for
- * @param pp priority and preferences to use by default
- */
- void
- GNUNET_MQ_set_options (struct GNUNET_MQ_Handle *mq,
- enum GNUNET_MQ_PriorityPreferences pp);
- /**
- * Obtain the current length of the message queue.
- *
- * @param mq queue to inspect
- * @return number of queued, non-transmitted messages
- */
- unsigned int
- GNUNET_MQ_get_length (struct GNUNET_MQ_Handle *mq);
- /**
- * Send a message with the given message queue.
- * May only be called once per message.
- *
- * @param mq message queue
- * @param ev the envelope with the message to send.
- */
- void
- GNUNET_MQ_send (struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev);
- /**
- * Send a copy of a message with the given message queue.
- * Can be called repeatedly on the same envelope.
- *
- * @param mq message queue
- * @param ev the envelope with the message to send.
- */
- void
- GNUNET_MQ_send_copy (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MQ_Envelope *ev);
- /**
- * Cancel sending the message. Message must have been sent with
- * #GNUNET_MQ_send before. May not be called after the notify sent
- * callback has been called
- *
- * @param ev queued envelope to cancel
- */
- void
- GNUNET_MQ_send_cancel (struct GNUNET_MQ_Envelope *ev);
- /**
- * Associate the assoc_data in @a mq with a unique request id.
- *
- * @param mq message queue, id will be unique for the queue
- * @param assoc_data to associate
- */
- uint32_t
- GNUNET_MQ_assoc_add (struct GNUNET_MQ_Handle *mq, void *assoc_data);
- /**
- * Get the data associated with a @a request_id in a queue
- *
- * @param mq the message queue with the association
- * @param request_id the request id we are interested in
- * @return the associated data
- */
- void *
- GNUNET_MQ_assoc_get (struct GNUNET_MQ_Handle *mq, uint32_t request_id);
- /**
- * Remove the association for a @a request_id
- *
- * @param mq the message queue with the association
- * @param request_id the request id we want to remove
- * @return the associated data
- */
- void *
- GNUNET_MQ_assoc_remove (struct GNUNET_MQ_Handle *mq, uint32_t request_id);
- /**
- * Create a message queue for the specified handlers.
- *
- * @param send function the implements sending messages
- * @param destroy function that implements destroying the queue
- * @param cancel function that implements canceling a message
- * @param impl_state for the queue, passed to @a send, @a destroy and @a cancel
- * @param handlers array of message handlers
- * @param error_handler handler for read and write errors
- * @param cls closure for message handlers and error handler
- * @return a new message queue
- */
- struct GNUNET_MQ_Handle *
- GNUNET_MQ_queue_for_callbacks (GNUNET_MQ_SendImpl send,
- GNUNET_MQ_DestroyImpl destroy,
- GNUNET_MQ_CancelImpl cancel,
- void *impl_state,
- const struct GNUNET_MQ_MessageHandler *handlers,
- GNUNET_MQ_ErrorHandler error_handler,
- void *cls);
- /**
- * Change the closure argument in all of the `handlers` of the
- * @a mq.
- *
- * @param mq to modify
- * @param handlers_cls new closure to use
- */
- void
- GNUNET_MQ_set_handlers_closure (struct GNUNET_MQ_Handle *mq,
- void *handlers_cls);
- /**
- * Call a callback once the envelope has been sent, that is,
- * sending it can not be canceled anymore.
- * There can be only one notify sent callback per envelope.
- *
- * @param ev message to call the notify callback for
- * @param cb the notify callback
- * @param cb_cls closure for the callback
- */
- void
- GNUNET_MQ_notify_sent (struct GNUNET_MQ_Envelope *ev,
- GNUNET_SCHEDULER_TaskCallback cb,
- void *cb_cls);
- /**
- * Destroy the message queue.
- *
- * @param mq message queue to destroy
- */
- void
- GNUNET_MQ_destroy (struct GNUNET_MQ_Handle *mq);
- /**
- * Handle we return for callbacks registered to be
- * notified when #GNUNET_MQ_destroy() is called on a queue.
- */
- struct GNUNET_MQ_DestroyNotificationHandle;
- /**
- * Register function to be called whenever @a mq is being
- * destroyed.
- *
- * @param mq message queue to watch
- * @param cb function to call on @a mq destruction
- * @param cb_cls closure for @a cb
- * @return handle for #GNUNET_MQ_destroy_notify_cancel().
- */
- struct GNUNET_MQ_DestroyNotificationHandle *
- GNUNET_MQ_destroy_notify (struct GNUNET_MQ_Handle *mq,
- GNUNET_SCHEDULER_TaskCallback cb,
- void *cb_cls);
- /**
- * Cancel registration from #GNUNET_MQ_destroy_notify().
- *
- * @param dnh handle for registration to cancel
- */
- void
- GNUNET_MQ_destroy_notify_cancel (
- struct GNUNET_MQ_DestroyNotificationHandle *dnh);
- /**
- * Call the message message handler that was registered
- * for the type of the given message in the given message queue.
- *
- * This function is indended to be used for the implementation
- * of message queues.
- *
- * @param mq message queue with the handlers
- * @param mh message to dispatch
- */
- void
- GNUNET_MQ_inject_message (struct GNUNET_MQ_Handle *mq,
- const struct GNUNET_MessageHeader *mh);
- /**
- * Call the error handler of a message queue with the given
- * error code. If there is no error handler, log a warning.
- *
- * This function is intended to be used for the implementation
- * of message queues.
- *
- * @param mq message queue
- * @param error the error type
- */
- void
- GNUNET_MQ_inject_error (struct GNUNET_MQ_Handle *mq,
- enum GNUNET_MQ_Error error);
- /**
- * Call the send implementation for the next queued message, if any.
- * Calls the send notification for the current message unless
- * #GNUNET_MQ_impl_send_in_flight was called for this envelope.
- *
- * Only useful for implementing message queues, results in undefined
- * behavior if not used carefully.
- *
- * @param mq message queue to send the next message with
- */
- void
- GNUNET_MQ_impl_send_continue (struct GNUNET_MQ_Handle *mq);
- /**
- * Call the send notification for the current message, but do not
- * try to send the next message until #gnunet_mq_impl_send_continue
- * is called.
- *
- * Only useful for implementing message queues, results in undefined
- * behavior if not used carefully.
- *
- * @param mq message queue to send the next message with
- */
- void
- GNUNET_MQ_impl_send_in_flight (struct GNUNET_MQ_Handle *mq);
- /**
- * Get the implementation state associated with the
- * message queue.
- *
- * While the GNUNET_MQ_Impl* callbacks receive the
- * implementation state, continuations that are scheduled
- * by the implementation function often only have one closure
- * argument, with this function it is possible to get at the
- * implementation state when only passing the `struct GNUNET_MQ_Handle`
- * as closure.
- *
- * @param mq message queue with the current message
- * @return message to send, never NULL
- */
- void *
- GNUNET_MQ_impl_state (struct GNUNET_MQ_Handle *mq);
- /**
- * Get the message that should currently be sent.
- * Fails if there is no current message.
- * Only useful for implementing message queues,
- * results in undefined behavior if not used carefully.
- *
- * @param mq message queue with the current message
- * @return message to send, never NULL
- */
- const struct GNUNET_MessageHeader *
- GNUNET_MQ_impl_current (struct GNUNET_MQ_Handle *mq);
- /**
- * Enum defining all known preference categories.
- *
- * @deprecated will be replaced by `enum GNUNET_MQ_PriorityPreference`
- */
- enum GNUNET_MQ_PreferenceKind
- {
- /**
- * No preference was expressed.
- */
- GNUNET_MQ_PREFERENCE_NONE = 0,
- /**
- * The preferred transmission for this envelope focuses on
- * maximizing bandwidth.
- */
- GNUNET_MQ_PREFERENCE_BANDWIDTH = 1,
- /**
- * The preferred transmission for this envelope foces on
- * minimizing latency.
- */
- GNUNET_MQ_PREFERENCE_LATENCY = 2,
- /**
- * The preferred transmission for this envelope foces on
- * reliability.
- */
- GNUNET_MQ_PREFERENCE_RELIABILITY = 3
- /**
- * Number of preference values allowed.
- */
- #define GNUNET_MQ_PREFERENCE_COUNT 4
- };
- /**
- * Convert an `enum GNUNET_MQ_PreferenceType` to a string
- *
- * @param type the preference type
- * @return a string or NULL if invalid
- *
- * @deprecated will be replaced by `enum GNUNET_MQ_PriorityPreference`
- */
- const char *
- GNUNET_MQ_preference_to_string (enum GNUNET_MQ_PreferenceKind type);
- #endif
- /** @} */ /* end of group mq */
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