| /**************************************************************************** |
| * net/tcp/tcp_timer.c |
| * Poll for the availability of TCP TX data |
| * |
| * Copyright (C) 2007-2010 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 <debug.h> |
| |
| #include <nuttx/net/netconfig.h> |
| #include <nuttx/net/uip.h> |
| #include <nuttx/net/netdev.h> |
| |
| #include "uip/uip.h" |
| #include "tcp/tcp.h" |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Public Variables |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Variables |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: tcp_timer |
| * |
| * Description: |
| * Handle a TCP timer expiration for the provided TCP connection |
| * |
| * Parameters: |
| * dev - The device driver structure to use in the send operation |
| * conn - The TCP "connection" to poll for TX data |
| * hsed - The polling interval in halves of a second |
| * |
| * Return: |
| * None |
| * |
| * Assumptions: |
| * Called from the interrupt level or with interrupts disabled. |
| * |
| ****************************************************************************/ |
| |
| void tcp_timer(FAR struct uip_driver_s *dev, FAR struct tcp_conn_s *conn, |
| int hsec) |
| { |
| uint8_t result; |
| |
| dev->d_snddata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN]; |
| dev->d_appdata = &dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN]; |
| |
| /* Increase the TCP sequence number */ |
| |
| tcp_nextsequence(); |
| |
| /* Reset the length variables. */ |
| |
| dev->d_len = 0; |
| dev->d_sndlen = 0; |
| |
| /* Check if the connection is in a state in which we simply wait |
| * for the connection to time out. If so, we increase the |
| * connection's timer and remove the connection if it times |
| * out. |
| */ |
| |
| if (conn->tcpstateflags == UIP_TIME_WAIT || |
| conn->tcpstateflags == UIP_FIN_WAIT_2) |
| { |
| /* Increment the connection timer */ |
| |
| conn->timer += hsec; |
| if (conn->timer >= UIP_TIME_WAIT_TIMEOUT) |
| { |
| conn->tcpstateflags = UIP_CLOSED; |
| |
| /* Notify upper layers about the timeout */ |
| |
| result = tcp_callback(dev, conn, UIP_TIMEDOUT); |
| |
| nllvdbg("TCP state: UIP_CLOSED\n"); |
| } |
| } |
| else if (conn->tcpstateflags != UIP_CLOSED) |
| { |
| /* If the connection has outstanding data, we increase the connection's |
| * timer and see if it has reached the RTO value in which case we |
| * retransmit. |
| */ |
| |
| if (conn->unacked > 0) |
| { |
| /* The connection has outstanding data */ |
| |
| if (conn->timer > hsec) |
| { |
| /* Will not yet decrement to zero */ |
| |
| conn->timer -= hsec; |
| } |
| else |
| { |
| /* Will decrement to zero */ |
| |
| conn->timer = 0; |
| |
| /* Should we close the connection? */ |
| |
| if ( |
| #ifdef CONFIG_NET_TCP_WRITE_BUFFERS |
| conn->expired > 0 || |
| #else |
| conn->nrtx == UIP_MAXRTX || |
| #endif |
| ((conn->tcpstateflags == UIP_SYN_SENT || |
| conn->tcpstateflags == UIP_SYN_RCVD) && |
| conn->nrtx == UIP_MAXSYNRTX) |
| ) |
| { |
| conn->tcpstateflags = UIP_CLOSED; |
| nllvdbg("TCP state: UIP_CLOSED\n"); |
| |
| /* We call tcp_callback() with UIP_TIMEDOUT to |
| * inform the application that the connection has |
| * timed out. |
| */ |
| |
| result = tcp_callback(dev, conn, UIP_TIMEDOUT); |
| |
| /* We also send a reset packet to the remote host. */ |
| |
| tcp_send(dev, conn, TCP_RST | TCP_ACK, UIP_IPTCPH_LEN); |
| goto done; |
| } |
| |
| /* Exponential backoff. */ |
| |
| conn->timer = UIP_RTO << (conn->nrtx > 4 ? 4: conn->nrtx); |
| (conn->nrtx)++; |
| |
| /* Ok, so we need to retransmit. We do this differently |
| * depending on which state we are in. In ESTABLISHED, we |
| * call upon the application so that it may prepare the |
| * data for the retransmit. In SYN_RCVD, we resend the |
| * SYNACK that we sent earlier and in LAST_ACK we have to |
| * retransmit our FINACK. |
| */ |
| |
| #ifdef CONFIG_NET_STATISTICS |
| uip_stat.tcp.rexmit++; |
| #endif |
| switch(conn->tcpstateflags & UIP_TS_MASK) |
| { |
| case UIP_SYN_RCVD: |
| /* In the SYN_RCVD state, we should retransmit our |
| * SYNACK. |
| */ |
| |
| tcp_ack(dev, conn, TCP_ACK | TCP_SYN); |
| goto done; |
| |
| case UIP_SYN_SENT: |
| /* In the SYN_SENT state, we retransmit out SYN. */ |
| |
| tcp_ack(dev, conn, TCP_SYN); |
| goto done; |
| |
| case UIP_ESTABLISHED: |
| /* In the ESTABLISHED state, we call upon the application |
| * to do the actual retransmit after which we jump into |
| * the code for sending out the packet. |
| */ |
| |
| result = tcp_callback(dev, conn, UIP_REXMIT); |
| tcp_rexmit(dev, conn, result); |
| goto done; |
| |
| case UIP_FIN_WAIT_1: |
| case UIP_CLOSING: |
| case UIP_LAST_ACK: |
| /* In all these states we should retransmit a FINACK. */ |
| |
| tcp_send(dev, conn, TCP_FIN | TCP_ACK, UIP_IPTCPH_LEN); |
| goto done; |
| } |
| } |
| } |
| |
| /* The connection does not have outstanding data */ |
| |
| else if ((conn->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) |
| { |
| /* If there was no need for a retransmission, we poll the |
| * application for new data. |
| */ |
| |
| result = tcp_callback(dev, conn, UIP_POLL); |
| tcp_appsend(dev, conn, result); |
| goto done; |
| } |
| } |
| |
| /* Nothing to be done */ |
| |
| dev->d_len = 0; |
| |
| done: |
| return; |
| } |
| |
| #endif /* CONFIG_NET && CONFIG_NET_TCP */ |
