/**************************************************************************** * net/tcp/tcp_appsend.c * * Copyright (C) 2007-2010, 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Adapted for NuttX from logic in uIP which also has a BSD-like license: * * Original author Adam Dunkels * 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 #if defined(CONFIG_NET) && defined(CONFIG_NET_TCP) #include #include #include #include #include #include #include "uip/uip.h" #include "tcp/tcp.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Public Variables ****************************************************************************/ /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_appsend * * 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 tcp_appsend(FAR struct uip_driver_s *dev, FAR struct tcp_conn_s *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"); tcp_send(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; tcp_send(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 */ tcp_rexmit(dev, conn, result); } } /**************************************************************************** * Name: tcp_rexmit * * 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 tcp_rexmit(FAR struct uip_driver_s *dev, FAR struct tcp_conn_s *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. */ tcp_send(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) { tcp_send(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 */