uip-split.h

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/*
 * Copyright (c) 2004, Swedish Institute of Computer Science.
 * All rights reserved. 
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 * 3. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 * SUCH DAMAGE. 
 *
 * This file is part of the Contiki operating system.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 * $Id: uip-split.h,v 1.1 2006/06/17 22:41:19 adamdunkels Exp $
 */
/**
 * \addtogroup uip
 * @{
 */

/**
 * \defgroup uipsplit uIP TCP throughput booster hack
 * @{
 *
 * The basic uIP TCP implementation only allows each TCP connection to
 * have a single TCP segment in flight at any given time. Because of
 * the delayed ACK algorithm employed by most TCP receivers, uIP's
 * limit on the amount of in-flight TCP segments seriously reduces the
 * maximum achievable throughput for sending data from uIP.
 *
 * The uip-split module is a hack which tries to remedy this
 * situation. By splitting maximum sized outgoing TCP segments into
 * two, the delayed ACK algorithm is not invoked at TCP
 * receivers. This improves the throughput when sending data from uIP
 * by orders of magnitude.
 *
 * The uip-split module uses the uip-fw module (uIP IP packet
 * forwarding) for sending packets. Therefore, the uip-fw module must
 * be set up with the appropriate network interfaces for this module
 * to work.
 */


/**
 * \file
 * Module for splitting outbound TCP segments in two to avoid the
 * delayed ACK throughput degradation. 
 * \author
 * Adam Dunkels <adam@sics.se>
 *
 */

#ifndef __UIP_SPLIT_H__
#define __UIP_SPLIT_H__

/**
 * Handle outgoing packets.
 *
 * This function inspects an outgoing packet in the uip_buf buffer and
 * sends it out using the uip_fw_output() function. If the packet is a
 * full-sized TCP segment it will be split into two segments and
 * transmitted separately. This function should be called instead of
 * the actual device driver output function, or the uip_fw_output()
 * function.
 *
 * The headers of the outgoing packet is assumed to be in the uip_buf
 * buffer and the payload is assumed to be wherever uip_appdata
 * points. The length of the outgoing packet is assumed to be in the
 * uip_len variable.
 *
 */
void uip_split_output(void);

#endif /* __UIP_SPLIT_H__ */

/** @} */
/** @} */