847 lines
27 KiB
C
847 lines
27 KiB
C
/****************************************************************************
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* net/tcp/tcp_input.c
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* Handling incoming TCP input
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*
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* Copyright (C) 2007-2014 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 <string.h>
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#include <debug.h>
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#include <nuttx/net/netconfig.h>
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#include <nuttx/net/uip.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/tcp.h>
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#include <nuttx/net/netstats.h>
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#include "devif/devif.h"
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#include "utils/utils.h"
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#include "tcp/tcp.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define BUF ((struct tcp_iphdr_s *)&dev->d_buf[NET_LLH_LEN])
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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: tcp_input
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*
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* Description:
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* Handle incoming TCP input
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*
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* Parameters:
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* dev - The device driver structure containing the received TCP packet.
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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 tcp_input(struct net_driver_s *dev)
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{
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struct tcp_conn_s *conn = NULL;
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struct tcp_iphdr_s *pbuf = BUF;
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uint16_t tmp16;
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uint16_t flags;
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uint8_t opt;
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uint8_t result;
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int len;
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int i;
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dev->d_snddata = &dev->d_buf[UIP_IPTCPH_LEN + NET_LLH_LEN];
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dev->d_appdata = &dev->d_buf[UIP_IPTCPH_LEN + NET_LLH_LEN];
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.tcp.recv++;
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#endif
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/* Start of TCP input header processing code. */
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if (tcp_chksum(dev) != 0xffff)
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{
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/* Compute and check the TCP checksum. */
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.tcp.drop++;
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g_netstats.tcp.chkerr++;
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#endif
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nlldbg("Bad TCP checksum\n");
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goto drop;
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}
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/* Demultiplex this segment. First check any active connections. */
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conn = tcp_active(pbuf);
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if (conn)
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{
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/* We found an active connection.. Check for the subsequent SYN
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* arriving in UIP_SYN_RCVD state after the SYNACK packet was
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* lost. To avoid other issues, reset any active connection
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* where a SYN arrives in a state != UIP_SYN_RCVD.
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*/
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if ((conn->tcpstateflags & UIP_TS_MASK) != UIP_SYN_RCVD &&
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(BUF->flags & TCP_CTL) == TCP_SYN)
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{
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goto reset;
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}
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else
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{
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goto found;
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}
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}
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/* If we didn't find and active connection that expected the packet,
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* either (1) this packet is an old duplicate, or (2) this is a SYN packet
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* destined for a connection in LISTEN. If the SYN flag isn't set,
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* it is an old packet and we send a RST.
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*/
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if ((pbuf->flags & TCP_CTL) == TCP_SYN)
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{
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/* This is a SYN packet for a connection. Find the connection
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* listening on this port.
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*/
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tmp16 = pbuf->destport;
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if (tcp_islistener(tmp16))
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{
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/* We matched the incoming packet with a connection in LISTEN.
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* We now need to create a new connection and send a SYNACK in
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* response.
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*/
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/* First allocate a new connection structure and see if there is any
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* user application to accept it.
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*/
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conn = tcp_alloc_accept(pbuf);
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if (conn)
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{
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/* The connection structure was successfully allocated. Now see if
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* there is an application waiting to accept the connection (or at
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* least queue it it for acceptance).
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*/
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conn->crefs = 1;
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if (tcp_accept_connection(dev, conn, tmp16) != OK)
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{
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/* No, then we have to give the connection back and drop the packet */
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conn->crefs = 0;
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tcp_free(conn);
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conn = NULL;
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}
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}
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if (!conn)
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{
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/* Either (1) all available connections are in use, or (2) there is no
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* application in place to accept the connection. We drop packet and hope that
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* the remote end will retransmit the packet at a time when we
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* have more spare connections or someone waiting to accept the connection.
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*/
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.tcp.syndrop++;
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#endif
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nlldbg("No free TCP connections\n");
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goto drop;
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}
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net_incr32(conn->rcvseq, 1);
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/* Parse the TCP MSS option, if present. */
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if ((pbuf->tcpoffset & 0xf0) > 0x50)
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{
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for (i = 0; i < ((pbuf->tcpoffset >> 4) - 5) << 2 ;)
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{
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opt = dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + i];
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if (opt == TCP_OPT_END)
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{
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/* End of options. */
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break;
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}
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else if (opt == TCP_OPT_NOOP)
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{
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/* NOP option. */
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++i;
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}
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else if (opt == TCP_OPT_MSS &&
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dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN)
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{
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/* An MSS option with the right option length. */
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tmp16 = ((uint16_t)dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 2 + i] << 8) |
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(uint16_t)dev->d_buf[UIP_IPTCPH_LEN + NET_LLH_LEN + 3 + i];
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conn->mss = tmp16 > TCP_MSS ? TCP_MSS : tmp16;
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/* And we are done processing options. */
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break;
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}
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else
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{
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/* All other options have a length field, so that we easily
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* can skip past them.
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*/
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if (dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i] == 0)
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{
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/* If the length field is zero, the options are malformed
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* and we don't process them further.
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*/
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break;
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}
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i += dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i];
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}
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}
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}
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/* Our response will be a SYNACK. */
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tcp_ack(dev, conn, TCP_ACK | TCP_SYN);
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return;
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}
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}
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/* This is (1) an old duplicate packet or (2) a SYN packet but with
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* no matching listener found. Send RST packet in either case.
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*/
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reset:
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/* We do not send resets in response to resets. */
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if ((pbuf->flags & TCP_RST) != 0)
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{
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goto drop;
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}
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#ifdef CONFIG_NET_STATISTICS
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g_netstats.tcp.synrst++;
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#endif
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tcp_reset(dev);
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return;
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found:
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/* Update the connection's window size */
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conn->winsize = ((uint16_t)pbuf->wnd[0] << 8) + (uint16_t)pbuf->wnd[1];
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flags = 0;
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/* We do a very naive form of TCP reset processing; we just accept
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* any RST and kill our connection. We should in fact check if the
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* sequence number of this reset is within our advertised window
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* before we accept the reset.
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*/
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if ((pbuf->flags & TCP_RST) != 0)
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{
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conn->tcpstateflags = UIP_CLOSED;
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nlldbg("RESET - TCP state: UIP_CLOSED\n");
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(void)tcp_callback(dev, conn, UIP_ABORT);
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goto drop;
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}
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/* Calculated the length of the data, if the application has sent
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* any data to us.
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*/
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len = (pbuf->tcpoffset >> 4) << 2;
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/* d_len will contain the length of the actual TCP data. This is
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* calculated by subtracting the length of the TCP header (in
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* len) and the length of the IP header (20 bytes).
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*/
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dev->d_len -= (len + IPHDR_LEN);
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/* First, check if the sequence number of the incoming packet is
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* what we're expecting next. If not, we send out an ACK with the
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* correct numbers in, unless we are in the SYN_RCVD state and
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* receive a SYN, in which case we should retransmit our SYNACK
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* (which is done further down).
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*/
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if (!((((conn->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) &&
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((pbuf->flags & TCP_CTL) == (TCP_SYN | TCP_ACK))) ||
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(((conn->tcpstateflags & UIP_TS_MASK) == UIP_SYN_RCVD) &&
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((pbuf->flags & TCP_CTL) == TCP_SYN))))
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{
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if ((dev->d_len > 0 || ((pbuf->flags & (TCP_SYN | TCP_FIN)) != 0)) &&
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memcmp(pbuf->seqno, conn->rcvseq, 4) != 0)
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{
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tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
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return;
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}
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}
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/* Next, check if the incoming segment acknowledges any outstanding
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* data. If so, we update the sequence number, reset the length of
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* the outstanding data, calculate RTT estimations, and reset the
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* retransmission timer.
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*/
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if ((pbuf->flags & TCP_ACK) != 0 && conn->unacked > 0)
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{
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uint32_t unackseq;
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uint32_t ackseq;
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/* The next sequence number is equal to the current sequence
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* number (sndseq) plus the size of the outstanding, unacknowledged
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* data (unacked).
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*/
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#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
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unackseq = conn->isn + conn->sent;
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#else
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unackseq = tcp_addsequence(conn->sndseq, conn->unacked);
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#endif
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/* Get the sequence number of that has just been acknowledged by this
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* incoming packet.
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*/
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ackseq = tcp_getsequence(pbuf->ackno);
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/* Check how many of the outstanding bytes have been acknowledged. For
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* a most uIP send operation, this should always be true. However,
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* the send() API sends data ahead when it can without waiting for
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* the ACK. In this case, the 'ackseq' could be less than then the
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* new sequence number.
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*/
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if (ackseq <= unackseq)
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{
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/* Calculate the new number of outstanding, unacknowledged bytes */
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conn->unacked = unackseq - ackseq;
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}
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else
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{
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/* What would it mean if ackseq > unackseq? The peer has ACKed
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* more bytes than we think we have sent? Someone has lost it.
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* Complain and reset the number of outstanding, unacknowledged
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* bytes
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*/
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if ((conn->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED)
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{
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nlldbg("ERROR: conn->sndseq %d, conn->unacked %d\n",
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tcp_getsequence(conn->sndseq), conn->unacked);
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goto reset;
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}
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}
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/* Update sequence number to the unacknowledge sequence number. If
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* there is still outstanding, unacknowledged data, then this will
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* be beyond ackseq.
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*/
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nllvdbg("sndseq: %08x->%08x unackseq: %08x new unacked: %d\n",
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conn->sndseq, ackseq, unackseq, conn->unacked);
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tcp_setsequence(conn->sndseq, ackseq);
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/* Do RTT estimation, unless we have done retransmissions. */
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if (conn->nrtx == 0)
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{
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signed char m;
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m = conn->rto - conn->timer;
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/* This is taken directly from VJs original code in his paper */
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m = m - (conn->sa >> 3);
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conn->sa += m;
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if (m < 0)
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{
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m = -m;
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}
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m = m - (conn->sv >> 2);
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conn->sv += m;
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conn->rto = (conn->sa >> 3) + conn->sv;
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}
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/* Set the acknowledged flag. */
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flags |= UIP_ACKDATA;
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/* Reset the retransmission timer. */
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conn->timer = conn->rto;
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}
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/* Do different things depending on in what state the connection is. */
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switch (conn->tcpstateflags & UIP_TS_MASK)
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{
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/* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
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* implemented, since we force the application to close when the
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* peer sends a FIN (hence the application goes directly from
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* ESTABLISHED to LAST_ACK).
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*/
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case UIP_SYN_RCVD:
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/* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
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* we are waiting for an ACK that acknowledges the data we sent
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* out the last time. Therefore, we want to have the UIP_ACKDATA
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* flag set. If so, we enter the ESTABLISHED state.
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*/
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if ((flags & UIP_ACKDATA) != 0)
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{
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conn->tcpstateflags = UIP_ESTABLISHED;
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#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
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conn->isn = tcp_getsequence(pbuf->ackno);
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tcp_setsequence(conn->sndseq, conn->isn);
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conn->sent = 0;
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#endif
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conn->unacked = 0;
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flags = UIP_CONNECTED;
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nllvdbg("TCP state: UIP_ESTABLISHED\n");
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if (dev->d_len > 0)
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{
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flags |= UIP_NEWDATA;
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net_incr32(conn->rcvseq, dev->d_len);
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}
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dev->d_sndlen = 0;
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result = tcp_callback(dev, conn, flags);
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tcp_appsend(dev, conn, result);
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return;
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}
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/* We need to retransmit the SYNACK */
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if ((pbuf->flags & TCP_CTL) == TCP_SYN)
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{
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tcp_ack(dev, conn, TCP_ACK | TCP_SYN);
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return;
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}
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goto drop;
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case UIP_SYN_SENT:
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/* In SYN_SENT, we wait for a SYNACK that is sent in response to
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* our SYN. The rcvseq is set to sequence number in the SYNACK
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* plus one, and we send an ACK. We move into the ESTABLISHED
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* state.
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*/
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if ((flags & UIP_ACKDATA) != 0 && (pbuf->flags & TCP_CTL) == (TCP_SYN | TCP_ACK))
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{
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/* Parse the TCP MSS option, if present. */
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if ((pbuf->tcpoffset & 0xf0) > 0x50)
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{
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for (i = 0; i < ((pbuf->tcpoffset >> 4) - 5) << 2 ;)
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{
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opt = dev->d_buf[UIP_IPTCPH_LEN + NET_LLH_LEN + i];
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if (opt == TCP_OPT_END)
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{
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/* End of options. */
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break;
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}
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else if (opt == TCP_OPT_NOOP)
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{
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/* NOP option. */
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++i;
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}
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else if (opt == TCP_OPT_MSS &&
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dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i] == TCP_OPT_MSS_LEN)
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{
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/* An MSS option with the right option length. */
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tmp16 =
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(dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 2 + i] << 8) |
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dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 3 + i];
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conn->mss = tmp16 > TCP_MSS ? TCP_MSS : tmp16;
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/* And we are done processing options. */
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break;
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}
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else
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{
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/* All other options have a length field, so that we
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* easily can skip past them.
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*/
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if (dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i] == 0)
|
|
{
|
|
/* If the length field is zero, the options are
|
|
* malformed and we don't process them further.
|
|
*/
|
|
|
|
break;
|
|
}
|
|
i += dev->d_buf[UIP_TCPIP_HLEN + NET_LLH_LEN + 1 + i];
|
|
}
|
|
}
|
|
}
|
|
|
|
conn->tcpstateflags = UIP_ESTABLISHED;
|
|
memcpy(conn->rcvseq, pbuf->seqno, 4);
|
|
|
|
net_incr32(conn->rcvseq, 1);
|
|
conn->unacked = 0;
|
|
|
|
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
|
|
conn->isn = tcp_getsequence(pbuf->ackno);
|
|
tcp_setsequence(conn->sndseq, conn->isn);
|
|
#endif
|
|
dev->d_len = 0;
|
|
dev->d_sndlen = 0;
|
|
|
|
nllvdbg("TCP state: UIP_ESTABLISHED\n");
|
|
result = tcp_callback(dev, conn, UIP_CONNECTED | UIP_NEWDATA);
|
|
tcp_appsend(dev, conn, result);
|
|
return;
|
|
}
|
|
|
|
/* Inform the application that the connection failed */
|
|
|
|
(void)tcp_callback(dev, conn, UIP_ABORT);
|
|
|
|
/* The connection is closed after we send the RST */
|
|
|
|
conn->tcpstateflags = UIP_CLOSED;
|
|
nllvdbg("Connection failed - TCP state: UIP_CLOSED\n");
|
|
|
|
/* We do not send resets in response to resets. */
|
|
|
|
if ((pbuf->flags & TCP_RST) != 0)
|
|
{
|
|
goto drop;
|
|
}
|
|
|
|
tcp_reset(dev);
|
|
return;
|
|
|
|
case UIP_ESTABLISHED:
|
|
/* In the ESTABLISHED state, we call upon the application to feed
|
|
* data into the d_buf. If the UIP_ACKDATA flag is set, the
|
|
* application should put new data into the buffer, otherwise we are
|
|
* retransmitting an old segment, and the application should put that
|
|
* data into the buffer.
|
|
*
|
|
* If the incoming packet is a FIN, we should close the connection on
|
|
* this side as well, and we send out a FIN and enter the LAST_ACK
|
|
* state. We require that there is no outstanding data; otherwise the
|
|
* sequence numbers will be screwed up.
|
|
*/
|
|
|
|
if ((pbuf->flags & TCP_FIN) != 0 && (conn->tcpstateflags & UIP_STOPPED) == 0)
|
|
{
|
|
/* Needs to be investigated further.
|
|
* Windows often sends FIN packets together with the last ACK for
|
|
* the received data. So the socket layer has to get this ACK even
|
|
* if the connection is going to be closed.
|
|
*/
|
|
#if 0
|
|
if (conn->unacked > 0)
|
|
{
|
|
goto drop;
|
|
}
|
|
#endif
|
|
|
|
/* Update the sequence number and indicate that the connection has
|
|
* been closed.
|
|
*/
|
|
|
|
net_incr32(conn->rcvseq, dev->d_len + 1);
|
|
flags |= UIP_CLOSE;
|
|
|
|
if (dev->d_len > 0)
|
|
{
|
|
flags |= UIP_NEWDATA;
|
|
}
|
|
|
|
(void)tcp_callback(dev, conn, flags);
|
|
|
|
conn->tcpstateflags = UIP_LAST_ACK;
|
|
conn->unacked = 1;
|
|
conn->nrtx = 0;
|
|
nllvdbg("TCP state: UIP_LAST_ACK\n");
|
|
|
|
tcp_send(dev, conn, TCP_FIN | TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
}
|
|
|
|
/* Check the URG flag. If this is set, the segment carries urgent
|
|
* data that we must pass to the application.
|
|
*/
|
|
|
|
if ((pbuf->flags & TCP_URG) != 0)
|
|
{
|
|
#ifdef CONFIG_NET_TCPURGDATA
|
|
dev->d_urglen = (pbuf->urgp[0] << 8) | pbuf->urgp[1];
|
|
if (dev->d_urglen > dev->d_len)
|
|
{
|
|
/* There is more urgent data in the next segment to come. */
|
|
|
|
dev->d_urglen = dev->d_len;
|
|
}
|
|
|
|
net_incr32(conn->rcvseq, dev->d_urglen);
|
|
dev->d_len -= dev->d_urglen;
|
|
dev->d_urgdata = dev->d_appdata;
|
|
dev->d_appdata += dev->d_urglen;
|
|
}
|
|
else
|
|
{
|
|
dev->d_urglen = 0;
|
|
#else /* CONFIG_NET_TCPURGDATA */
|
|
dev->d_appdata = ((uint8_t*)dev->d_appdata) + ((pbuf->urgp[0] << 8) | pbuf->urgp[1]);
|
|
dev->d_len -= (pbuf->urgp[0] << 8) | pbuf->urgp[1];
|
|
#endif /* CONFIG_NET_TCPURGDATA */
|
|
}
|
|
|
|
/* If d_len > 0 we have TCP data in the packet, and we flag this
|
|
* by setting the UIP_NEWDATA flag. If the application has stopped
|
|
* the data flow using UIP_STOPPED, we must not accept any data
|
|
* packets from the remote host.
|
|
*/
|
|
|
|
if (dev->d_len > 0 && (conn->tcpstateflags & UIP_STOPPED) == 0)
|
|
{
|
|
flags |= UIP_NEWDATA;
|
|
}
|
|
|
|
/* If this packet constitutes an ACK for outstanding data (flagged
|
|
* by the UIP_ACKDATA flag), we should call the application since it
|
|
* might want to send more data. If the incoming packet had data
|
|
* from the peer (as flagged by the UIP_NEWDATA flag), the
|
|
* application must also be notified.
|
|
*
|
|
* When the application is called, the d_len field
|
|
* contains the length of the incoming data. The application can
|
|
* access the incoming data through the global pointer
|
|
* d_appdata, which usually points UIP_IPTCPH_LEN + NET_LLH_LEN
|
|
* bytes into the d_buf array.
|
|
*
|
|
* If the application wishes to send any data, this data should be
|
|
* put into the d_appdata and the length of the data should be
|
|
* put into d_len. If the application don't have any data to
|
|
* send, d_len must be set to 0.
|
|
*/
|
|
|
|
if ((flags & (UIP_NEWDATA | UIP_ACKDATA)) != 0)
|
|
{
|
|
/* Clear sndlen and remember the size in d_len. The application
|
|
* may modify d_len and we will need this value later when we
|
|
* update the sequence number.
|
|
*/
|
|
|
|
dev->d_sndlen = 0;
|
|
len = dev->d_len;
|
|
|
|
/* Provide the packet to the application */
|
|
|
|
result = tcp_callback(dev, conn, flags);
|
|
|
|
/* If the application successfully handled the incoming data,
|
|
* then UIP_SNDACK will be set in the result. In this case,
|
|
* we need to update the sequence number. The ACK will be
|
|
* send by tcp_appsend().
|
|
*/
|
|
|
|
if ((result & UIP_SNDACK) != 0)
|
|
{
|
|
/* Update the sequence number using the saved length */
|
|
|
|
net_incr32(conn->rcvseq, len);
|
|
}
|
|
|
|
/* Send the response, ACKing the data or not, as appropriate */
|
|
|
|
tcp_appsend(dev, conn, result);
|
|
return;
|
|
}
|
|
|
|
goto drop;
|
|
|
|
case UIP_LAST_ACK:
|
|
/* We can close this connection if the peer has acknowledged our
|
|
* FIN. This is indicated by the UIP_ACKDATA flag.
|
|
*/
|
|
|
|
if ((flags & UIP_ACKDATA) != 0)
|
|
{
|
|
conn->tcpstateflags = UIP_CLOSED;
|
|
nllvdbg("UIP_LAST_ACK TCP state: UIP_CLOSED\n");
|
|
|
|
(void)tcp_callback(dev, conn, UIP_CLOSE);
|
|
}
|
|
break;
|
|
|
|
case UIP_FIN_WAIT_1:
|
|
/* The application has closed the connection, but the remote host
|
|
* hasn't closed its end yet. Thus we stay in the FIN_WAIT_1 state
|
|
* until we receive a FIN from the remote.
|
|
*/
|
|
|
|
if (dev->d_len > 0)
|
|
{
|
|
net_incr32(conn->rcvseq, dev->d_len);
|
|
}
|
|
|
|
if ((pbuf->flags & TCP_FIN) != 0)
|
|
{
|
|
if ((flags & UIP_ACKDATA) != 0)
|
|
{
|
|
conn->tcpstateflags = UIP_TIME_WAIT;
|
|
conn->timer = 0;
|
|
conn->unacked = 0;
|
|
nllvdbg("TCP state: UIP_TIME_WAIT\n");
|
|
}
|
|
else
|
|
{
|
|
conn->tcpstateflags = UIP_CLOSING;
|
|
nllvdbg("TCP state: UIP_CLOSING\n");
|
|
}
|
|
|
|
net_incr32(conn->rcvseq, 1);
|
|
(void)tcp_callback(dev, conn, UIP_CLOSE);
|
|
tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
}
|
|
else if ((flags & UIP_ACKDATA) != 0)
|
|
{
|
|
conn->tcpstateflags = UIP_FIN_WAIT_2;
|
|
conn->unacked = 0;
|
|
nllvdbg("TCP state: UIP_FIN_WAIT_2\n");
|
|
goto drop;
|
|
}
|
|
|
|
if (dev->d_len > 0)
|
|
{
|
|
tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
}
|
|
|
|
goto drop;
|
|
|
|
case UIP_FIN_WAIT_2:
|
|
if (dev->d_len > 0)
|
|
{
|
|
net_incr32(conn->rcvseq, dev->d_len);
|
|
}
|
|
|
|
if ((pbuf->flags & TCP_FIN) != 0)
|
|
{
|
|
conn->tcpstateflags = UIP_TIME_WAIT;
|
|
conn->timer = 0;
|
|
nllvdbg("TCP state: UIP_TIME_WAIT\n");
|
|
|
|
net_incr32(conn->rcvseq, 1);
|
|
(void)tcp_callback(dev, conn, UIP_CLOSE);
|
|
tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
}
|
|
|
|
if (dev->d_len > 0)
|
|
{
|
|
tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
}
|
|
|
|
goto drop;
|
|
|
|
case UIP_TIME_WAIT:
|
|
tcp_send(dev, conn, TCP_ACK, UIP_IPTCPH_LEN);
|
|
return;
|
|
|
|
case UIP_CLOSING:
|
|
if ((flags & UIP_ACKDATA) != 0)
|
|
{
|
|
conn->tcpstateflags = UIP_TIME_WAIT;
|
|
conn->timer = 0;
|
|
nllvdbg("TCP state: UIP_TIME_WAIT\n");
|
|
}
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
drop:
|
|
dev->d_len = 0;
|
|
}
|
|
|
|
#endif /* CONFIG_NET && CONFIG_NET_TCP */
|