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nuttx/net/tcp/tcp_appsend.c

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/****************************************************************************
* net/tcp/tcp_appsend.c
*
* Copyright (C) 2007-2010, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Adapted for NuttX from logic in uIP which also has a BSD-like license:
*
* Original author Adam Dunkels <adam@dunkels.com>
* Copyright () 2001-2003, Adam Dunkels.
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP)
#include <stdint.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/uip/uip.h>
#include <nuttx/net/netdev.h>
#include "uip/uip_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: uip_tcpappsend
*
* Description:
* Handle application or TCP protocol response. If this function is called
* with dev->d_sndlen > 0, then this is an application attempting to send
* packet.
*
* Parameters:
* dev - The device driver structure to use in the send operation
* conn - The TCP connection structure holding connection information
* result - App result event sent
*
* Return:
* None
*
* Assumptions:
* Called from the interrupt level or with interrupts disabled.
*
****************************************************************************/
void uip_tcpappsend(struct uip_driver_s *dev, struct uip_conn *conn,
uint16_t result)
{
/* Handle the result based on the application response */
nllvdbg("result: %04x d_sndlen: %d conn->unacked: %d\n",
result, dev->d_sndlen, conn->unacked);
/* Check for connection aborted */
if ((result & UIP_ABORT) != 0)
{
dev->d_sndlen = 0;
conn->tcpstateflags = UIP_CLOSED;
nllvdbg("TCP state: UIP_CLOSED\n");
uip_tcpsend(dev, conn, TCP_RST | TCP_ACK, UIP_IPTCPH_LEN);
}
/* Check for connection closed */
else if ((result & UIP_CLOSE) != 0)
{
conn->tcpstateflags = UIP_FIN_WAIT_1;
conn->unacked = 1;
conn->nrtx = 0;
nllvdbg("TCP state: UIP_FIN_WAIT_1\n");
dev->d_sndlen = 0;
uip_tcpsend(dev, conn, TCP_FIN | TCP_ACK, UIP_IPTCPH_LEN);
}
/* None of the above */
else
{
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
DEBUGASSERT(dev->d_sndlen >= 0 && dev->d_sndlen <= conn->mss);
#else
/* If d_sndlen > 0, the application has data to be sent. */
if (dev->d_sndlen > 0)
{
/* Remember how much data we send out now so that we know
* when everything has been acknowledged. Just increment the amount
* of data sent. This will be needed in sequence number calculations
* and we know that this is not a re-transmission. Retransmissions
* do not go through this path.
*/
conn->unacked += dev->d_sndlen;
/* The application cannot send more than what is allowed by the
* MSS (the minumum of the MSS and the available window).
*/
DEBUGASSERT(dev->d_sndlen <= conn->mss);
}
conn->nrtx = 0;
#endif
/* Then handle the rest of the operation just as for the rexmit case */
uip_tcprexmit(dev, conn, result);
}
}
/****************************************************************************
* Name: uip_tcprexmit
*
* Description:
* Handle application retransmission
*
* Parameters:
* dev - The device driver structure to use in the send operation
* conn - The TCP connection structure holding connection information
* result - App result event sent
*
* Return:
* None
*
* Assumptions:
* Called from the interrupt level or with interrupts disabled.
*
****************************************************************************/
void uip_tcprexmit(struct uip_driver_s *dev, struct uip_conn *conn,
uint16_t result)
{
nllvdbg("result: %04x d_sndlen: %d conn->unacked: %d\n",
result, dev->d_sndlen, conn->unacked);
dev->d_appdata = dev->d_snddata;
/* If the application has data to be sent, or if the incoming packet had
* new data in it, we must send out a packet.
*/
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
if (dev->d_sndlen > 0)
#else
if (dev->d_sndlen > 0 && conn->unacked > 0)
#endif
{
/* We always set the ACK flag in response packets adding the length of
* the IP and TCP headers.
*/
uip_tcpsend(dev, conn, TCP_ACK | TCP_PSH, dev->d_sndlen + UIP_TCPIP_HLEN);
}
/* If there is no data to send, just send out a pure ACK if one is requested`. */
else if ((result & UIP_SNDACK) != 0)
{
uip_tcpsend(dev, conn, TCP_ACK, UIP_TCPIP_HLEN);
}
/* There is nothing to do -- drop the packet */
else
{
dev->d_len = 0;
}
}
#endif /* CONFIG_NET && CONFIG_NET_TCP */
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