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250 lines
8.4 KiB
250 lines
8.4 KiB
/**************************************************************************** |
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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 <gnutt@nuttx.org> |
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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 <nuttx/net/uip/uipopt.h> |
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#include <nuttx/net/uip/uip.h> |
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#include <nuttx/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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