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/****************************************************************************
* net/tcp/tcp_readahead.c
*
* Copyright (C) 2007-2009, 2013-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/net/netconfig.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) && defined(CONFIG_NET_TCP_READAHEAD)
#include <queue.h>
#include <debug.h>
#include <nuttx/net/uip.h>
#include "uip/uip.h"
/****************************************************************************
* Private Types
****************************************************************************/
/* Package all globals used by this logic into a structure */
struct readahead_s
{
/* This is the list of available write buffers */
sq_queue_t freebuffers;
/* These are the pre-allocated write buffers */
struct uip_readahead_s buffers[CONFIG_NET_NTCP_READAHEAD_BUFFERS];
};
/****************************************************************************
* Private Data
****************************************************************************/
/* This is the state of the global read-ahead resource */
static struct readahead_s g_readahead;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: uip_tcpreadahead_init
*
* Description:
* Initialize the list of free read-ahead buffers
*
* Assumptions:
* Called once early initialization.
*
****************************************************************************/
void uip_tcpreadahead_init(void)
{
int i;
sq_init(&g_readahead.freebuffers);
for (i = 0; i < CONFIG_NET_NTCP_READAHEAD_BUFFERS; i++)
{
sq_addfirst(&g_readahead.buffers[i].rh_node, &g_readahead.freebuffers);
}
}
/****************************************************************************
* Function: uip_tcpreadahead_alloc
*
* Description:
* Allocate a TCP read-ahead buffer by taking a pre-allocated buffer from
* the free list. This function is called from TCP logic when new,
* incoming TCP data is received but there is no user logic receiving the
* the data. Note: kmalloc() cannot be used because this function is
* called from interrupt level.
*
* Assumptions:
* Called from interrupt level with interrupts disabled.
*
****************************************************************************/
FAR struct uip_readahead_s *uip_tcpreadahead_alloc(void)
{
return (FAR struct uip_readahead_s*)sq_remfirst(&g_readahead.freebuffers);
}
/****************************************************************************
* Function: uip_tcpreadahead_release
*
* Description:
* Release a TCP read-ahead buffer by returning the buffer to the free list.
* This function is called from user logic after it is consumed the buffered
* data.
*
* Assumptions:
* Called from user logic BUT with interrupts disabled.
*
****************************************************************************/
void uip_tcpreadahead_release(FAR struct uip_readahead_s *readahead)
{
sq_addfirst(&readahead->rh_node, &g_readahead.freebuffers);
}
#endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCP_READAHEAD */
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