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/*
This file is part of GNUnet
Copyright (C) 2009, 2011, 2015 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/>.
*/
/**
* @author Christian Grothoff
*
* @file
* Library to help fragment messages
*
* @defgroup fragmentation Fragmentation library
* Library to help fragment messages
* @{
*
* @todo Consider additional flow-control for sending from
* fragmentation based on continuations.
*/
#ifndef GNUNET_FRAGMENTATION_LIB_H
#define GNUNET_FRAGMENTATION_LIB_H
#include "gnunet_util_lib.h"
#include "gnunet_bandwidth_lib.h"
#include "gnunet_statistics_service.h"
#ifdef __cplusplus
extern "C"
{
#if 0 /* keep Emacsens' auto-indent happy */
}
#endif
#endif
/**
* Fragmentation context.
*/
struct GNUNET_FRAGMENT_Context;
/**
* Function that is called with messages created by the fragmentation
* module. In the case of the 'proc' callback of the
* #GNUNET_FRAGMENT_context_create() function, this function must
* eventually call #GNUNET_FRAGMENT_context_transmission_done().
*
* @param cls closure
* @param msg the message that was created
*/
typedef void
(*GNUNET_FRAGMENT_MessageProcessor) (void *cls,
const struct GNUNET_MessageHeader *msg);
/**
* Create a fragmentation context for the given message.
* Fragments the message into fragments of size @a mtu or
* less. Calls @a proc on each un-acknowledged fragment,
* using both the expected @a msg_delay between messages and
* acknowledgements and the given @a tracker to guide the
* frequency of calls to @a proc.
*
* @param stats statistics context
* @param mtu the maximum message size for each fragment
* @param tracker bandwidth tracker to use for flow control (can be NULL)
* @param msg_delay initial delay to insert between fragment transmissions
* based on previous messages
* @param ack_delay expected delay between fragment transmission
* and ACK based on previous messages
* @param msg the message to fragment
* @param proc function to call for each fragment to transmit
* @param proc_cls closure for proc
* @return the fragmentation context
*/
struct GNUNET_FRAGMENT_Context *
GNUNET_FRAGMENT_context_create (struct GNUNET_STATISTICS_Handle *stats,
uint16_t mtu,
struct GNUNET_BANDWIDTH_Tracker *tracker,
struct GNUNET_TIME_Relative msg_delay,
struct GNUNET_TIME_Relative ack_delay,
const struct GNUNET_MessageHeader *msg,
GNUNET_FRAGMENT_MessageProcessor proc,
void *proc_cls);
/**
* Continuation to call from the 'proc' function after the fragment
* has been transmitted (and hence the next fragment can now be
* given to proc).
*
* @param fc fragmentation context
*/
void
GNUNET_FRAGMENT_context_transmission_done (struct GNUNET_FRAGMENT_Context *fc);
/**
* Process an acknowledgement message we got from the other
* side (to control re-transmits).
*
* @param fc fragmentation context
* @param msg acknowledgement message we received
* @return #GNUNET_OK if this ack completes the work of the 'fc'
* (all fragments have been received);
* #GNUNET_NO if more messages are pending
* #GNUNET_SYSERR if this ack is not valid for this fc
*/
int
GNUNET_FRAGMENT_process_ack (struct GNUNET_FRAGMENT_Context *fc,
const struct GNUNET_MessageHeader *msg);
/**
* Destroy the given fragmentation context (stop calling 'proc', free
* resources).
*
* @param fc fragmentation context
* @param msg_delay where to store average delay between individual message transmissions the
* last message (OUT only)
* @param ack_delay where to store average delay between transmission and ACK for the
* last message, set to FOREVER if the message was not fully transmitted (OUT only)
*/
void
GNUNET_FRAGMENT_context_destroy (struct GNUNET_FRAGMENT_Context *fc,
struct GNUNET_TIME_Relative *msg_delay,
struct GNUNET_TIME_Relative *ack_delay);
/**
* Convert an ACK message to a printable format suitable for logging.
*
* @param ack message to print
* @return ack in human-readable format
*/
const char *
GNUNET_FRAGMENT_print_ack (const struct GNUNET_MessageHeader *ack);
/**
* Defragmentation context (one per connection).
*/
struct GNUNET_DEFRAGMENT_Context;
/**
* Function that is called with acknowledgement messages created by
* the fragmentation module. Acknowledgements are cummulative,
* so it is OK to only transmit the 'latest' ack message for the same
* message ID.
*
* @param cls closure
* @param id unique message ID (modulo collisions)
* @param msg the message that was created
*/
typedef void
(*GNUNET_DEFRAGMENT_AckProcessor) (void *cls,
uint32_t id,
const struct GNUNET_MessageHeader *msg);
/**
* Create a defragmentation context.
*
* @param stats statistics context
* @param mtu the maximum message size for each fragment
* @param num_msgs how many fragmented messages
* to we defragment at most at the same time?
* @param cls closure for @a proc and @a ackp
* @param proc function to call with defragmented messages
* @param ackp function to call with acknowledgements (to send
* back to the other side)
* @return the defragmentation context
*/
struct GNUNET_DEFRAGMENT_Context *
GNUNET_DEFRAGMENT_context_create (struct GNUNET_STATISTICS_Handle *stats,
uint16_t mtu,
unsigned int num_msgs,
void *cls,
GNUNET_FRAGMENT_MessageProcessor proc,
GNUNET_DEFRAGMENT_AckProcessor ackp);
/**
* Destroy the given defragmentation context.
*
* @param dc defragmentation context
*/
void
GNUNET_DEFRAGMENT_context_destroy (struct GNUNET_DEFRAGMENT_Context *dc);
/**
* We have received a fragment. Process it.
*
* @param dc the context
* @param msg the message that was received
* @return #GNUNET_OK on success,
* #GNUNET_NO if this was a duplicate,
* #GNUNET_SYSERR on error
*/
int
GNUNET_DEFRAGMENT_process_fragment (struct GNUNET_DEFRAGMENT_Context *dc,
const struct GNUNET_MessageHeader *msg);
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif
#endif
/** @} */ /* end of group */
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