/*
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 .
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 (e.g. NSE, FS).
* This is the default!
*/
GNUNET_MQ_PRIO_BACKGROUND = 0,
/**
* Best-effort traffic (e.g. CADET relay, DHT)
*/
GNUNET_MQ_PRIO_BEST_EFFORT = 1,
/**
* Urgent traffic (local peer, e.g. Conversation).
*/
GNUNET_MQ_PRIO_URGENT = 2,
/**
* Highest priority, control traffic (e.g. 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 declared 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 declared 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 received.
* 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:
*
* 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:
*
* 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 indented 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 indented 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 */