251 lines
8.4 KiB
C
251 lines
8.4 KiB
C
/****************************************************************************
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* net/uip/uip_tcptimer.c
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* Poll for the availability of TCP TX data
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*
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* Copyright (C) 2007-2010 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Adapted for NuttX from logic in uIP which also has a BSD-like license:
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*
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* Original author Adam Dunkels <adam@dunkels.com>
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* Copyright () 2001-2003, Adam Dunkels.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#if defined(CONFIG_NET) && defined(CONFIG_NET_TCP)
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#include <stdint.h>
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#include <debug.h>
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#include <net/uip/uipopt.h>
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#include <net/uip/uip.h>
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#include <net/uip/uip-arch.h>
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#include "uip_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Variables
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: uip_tcptimer
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*
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* Description:
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* Handle a TCP timer expiration for the provided TCP connection
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*
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* Parameters:
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* dev - The device driver structure to use in the send operation
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* conn - The TCP "connection" to poll for TX data
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* hsed - The polling interval in halves of a second
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*
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* Return:
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* None
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*
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* Assumptions:
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* Called from the interrupt level or with interrupts disabled.
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*
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****************************************************************************/
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void uip_tcptimer(struct uip_driver_s *dev, struct uip_conn *conn, int hsec)
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{
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uint8_t result;
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dev->d_snddata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
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dev->d_appdata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
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/* Increase the TCP sequence number */
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uip_tcpnextsequence();
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/* Reset the length variables. */
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dev->d_len = 0;
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dev->d_sndlen = 0;
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/* Check if the connection is in a state in which we simply wait
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* for the connection to time out. If so, we increase the
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* connection's timer and remove the connection if it times
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* out.
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*/
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if (conn->tcpstateflags == UIP_TIME_WAIT || conn->tcpstateflags == UIP_FIN_WAIT_2)
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{
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/* Increment the connection timer */
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(conn->timer) += hsec;
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if (conn->timer >= UIP_TIME_WAIT_TIMEOUT)
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{
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conn->tcpstateflags = UIP_CLOSED;
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nllvdbg("TCP state: UIP_CLOSED\n");
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}
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}
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else if (conn->tcpstateflags != UIP_CLOSED)
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{
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/* If the connection has outstanding data, we increase the connection's
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* timer and see if it has reached the RTO value in which case we
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* retransmit.
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*/
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if (conn->unacked > 0)
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{
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/* The connection has outstanding data */
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if (conn->timer > hsec)
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{
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/* Will not yet decrement to zero */
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conn->timer -= hsec;
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}
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else
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{
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/* Will decrement to zero */
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conn->timer = 0;
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/* Should we close the connection? */
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if (conn->nrtx == UIP_MAXRTX ||
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((conn->tcpstateflags == UIP_SYN_SENT ||
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conn->tcpstateflags == UIP_SYN_RCVD) &&
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conn->nrtx == UIP_MAXSYNRTX))
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{
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conn->tcpstateflags = UIP_CLOSED;
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nllvdbg("TCP state: UIP_CLOSED\n");
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/* We call uip_tcpcallback() with UIP_TIMEDOUT to
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* inform the application that the connection has
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* timed out.
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*/
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result = uip_tcpcallback(dev, conn, UIP_TIMEDOUT);
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/* We also send a reset packet to the remote host. */
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uip_tcpsend(dev, conn, TCP_RST | TCP_ACK, UIP_IPTCPH_LEN);
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goto done;
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}
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/* Exponential backoff. */
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conn->timer = UIP_RTO << (conn->nrtx > 4 ? 4: conn->nrtx);
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(conn->nrtx)++;
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/* Ok, so we need to retransmit. We do this differently
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* depending on which state we are in. In ESTABLISHED, we
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* call upon the application so that it may prepare the
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* data for the retransmit. In SYN_RCVD, we resend the
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* SYNACK that we sent earlier and in LAST_ACK we have to
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* retransmit our FINACK.
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*/
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#ifdef CONFIG_NET_STATISTICS
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uip_stat.tcp.rexmit++;
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#endif
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switch(conn->tcpstateflags & UIP_TS_MASK)
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{
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case UIP_SYN_RCVD:
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/* In the SYN_RCVD state, we should retransmit our
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* SYNACK.
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*/
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uip_tcpack(dev, conn, TCP_ACK | TCP_SYN);
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goto done;
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case UIP_SYN_SENT:
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/* In the SYN_SENT state, we retransmit out SYN. */
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uip_tcpack(dev, conn, TCP_SYN);
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goto done;
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case UIP_ESTABLISHED:
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/* In the ESTABLISHED state, we call upon the application
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* to do the actual retransmit after which we jump into
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* the code for sending out the packet.
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*/
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result = uip_tcpcallback(dev, conn, UIP_REXMIT);
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uip_tcprexmit(dev, conn, result);
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goto done;
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case UIP_FIN_WAIT_1:
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case UIP_CLOSING:
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case UIP_LAST_ACK:
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/* In all these states we should retransmit a FINACK. */
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uip_tcpsend(dev, conn, TCP_FIN | TCP_ACK, UIP_IPTCPH_LEN);
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goto done;
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}
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}
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}
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/* The connection does not have outstanding data */
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else if ((conn->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED)
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{
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/* If there was no need for a retransmission, we poll the
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* application for new data.
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*/
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result = uip_tcpcallback(dev, conn, UIP_POLL);
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uip_tcpappsend(dev, conn, result);
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goto done;
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}
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}
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/* Nothing to be done */
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dev->d_len = 0;
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done:
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return;
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}
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#endif /* CONFIG_NET && CONFIG_NET_TCP */
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