338 lines
12 KiB
C
338 lines
12 KiB
C
/****************************************************************************
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* net/uip/uip_tcpcallback.c
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*
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* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* 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/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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* Private Data
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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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* Function: uip_readahead
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*
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* Description:
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* Copy as much received data as possible into the readahead buffer
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*
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* Assumptions:
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* This function is called at the interrupt level with interrupts disabled.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_TCP_READAHEAD
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static int uip_readahead(struct uip_readahead_s *readahead, uint8_t *buf,
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int len)
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{
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int available = CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead->rh_nbytes;
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int recvlen = 0;
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if (len > 0 && available > 0)
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{
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/* Get the length of the data to buffer. */
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if (len > available)
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{
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recvlen = available;
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}
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else
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{
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recvlen = len;
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}
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/* Copy the new appdata into the read-ahead buffer */
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memcpy(&readahead->rh_buffer[readahead->rh_nbytes], buf, recvlen);
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readahead->rh_nbytes += recvlen;
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}
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return recvlen;
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}
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#endif
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/****************************************************************************
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* Function: uip_dataevent
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*
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* Description:
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* Handle data that is not accepted by the application because there is no
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* listener in place ready to receive the data.
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*
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* Assumptions:
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* - The caller has checked that UIP_NEWDATA is set in flags and that is no
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* other handler available to process the incoming data.
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* - This function is called at the interrupt level with interrupts disabled.
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*
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****************************************************************************/
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static inline uint16_t
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uip_dataevent(FAR struct uip_driver_s *dev, FAR struct uip_conn *conn,
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uint16_t flags)
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{
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uint16_t ret;
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/* Assume that we will ACK the data. The data will be ACKed if it is
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* placed in the read-ahead buffer -OR- if it zero length
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*/
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ret = (flags & ~UIP_NEWDATA) | UIP_SNDACK;
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/* Is there new data? With non-zero length? (Certain connection events
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* can have zero-length with UIP_NEWDATA set just to cause an ACK).
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*/
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if (dev->d_len > 0)
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{
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#ifdef CONFIG_NET_TCP_READAHEAD
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uint8_t *buffer = dev->d_appdata;
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int buflen = dev->d_len;
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uint16_t recvlen;
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#endif
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nllvdbg("No listener on connection\n");
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#ifdef CONFIG_NET_TCP_READAHEAD
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/* Save as much data as possible in the read-ahead buffers */
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recvlen = uip_datahandler(conn, buffer, buflen);
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/* There are several complicated buffering issues that are not addressed
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* properly here. For example, what if we cannot buffer the entire
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* packet? In that case, some data will be accepted but not ACKed.
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* Therefore it will be resent and duplicated. Fixing this could be tricky.
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*/
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if (recvlen < buflen)
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#endif
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{
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/* There is no handler to receive new data and there are no free
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* read-ahead buffers to retain the data -- drop the packet.
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*/
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nllvdbg("Dropped %d bytes\n", dev->d_len);
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#ifdef CONFIG_NET_STATISTICS
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uip_stat.tcp.syndrop++;
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uip_stat.tcp.drop++;
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#endif
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/* Clear the UIP_SNDACK bit so that no ACK will be sent */
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ret &= ~UIP_SNDACK;
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}
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}
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/* In any event, the new data has now been handled */
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dev->d_len = 0;
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return ret;
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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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* Function: uip_tcpcallback
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*
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* Description:
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* Inform the application holding the TCP socket of a change in state.
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*
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* Assumptions:
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* This function is called at the interrupt level with interrupts disabled.
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*
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****************************************************************************/
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uint16_t uip_tcpcallback(struct uip_driver_s *dev, struct uip_conn *conn,
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uint16_t flags)
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{
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/* Preserve the UIP_ACKDATA, UIP_CLOSE, and UIP_ABORT in the response.
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* These is needed by uIP to handle responses and buffer state. The
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* UIP_NEWDATA indication will trigger the ACK response, but must be
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* explicitly set in the callback.
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*/
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nllvdbg("flags: %04x\n", flags);
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/* Perform the data callback. When a data callback is executed from 'list',
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* the input flags are normally returned, however, the implementation
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* may set one of the following:
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*
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* UIP_CLOSE - Gracefully close the current connection
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* UIP_ABORT - Abort (reset) the current connection on an error that
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* prevents UIP_CLOSE from working.
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*
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* And/Or set/clear the following:
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*
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* UIP_NEWDATA - May be cleared to indicate that the data was consumed
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* and that no further process of the new data should be
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* attempted.
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* UIP_SNDACK - If UIP_NEWDATA is cleared, then UIP_SNDACK may be set
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* to indicate that an ACK should be included in the response.
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* (In UIP_NEWDATA is cleared bu UIP_SNDACK is not set, then
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* dev->d_len should also be cleared).
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*/
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flags = uip_callbackexecute(dev, conn, flags, conn->list);
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/* There may be no new data handler in place at them moment that the new
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* incoming data is received. If the new incoming data was not handled, then
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* either (1) put the unhandled incoming data in the read-ahead buffer (if
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* enabled) or (2) suppress the ACK to the data in the hope that it will
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* be re-transmitted at a better time.
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*/
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if ((flags & UIP_NEWDATA) != 0)
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{
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/* Data was not handled.. dispose of it appropriately */
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flags = uip_dataevent(dev, conn, flags);
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}
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/* Check if there is a connection-related event and a connection
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* callback.
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*/
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if (((flags & UIP_CONN_EVENTS) != 0) && conn->connection_event)
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{
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/* Perform the callback */
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conn->connection_event(conn, flags);
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}
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return flags;
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}
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/****************************************************************************
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* Function: uip_datahandler
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*
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* Description:
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* Handle data that is not accepted by the application. This may be called
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* either (1) from the data receive logic if it cannot buffer the data, or
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* (2) from the TCP event logic is there is no listener in place ready to
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* receive the data.
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*
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* Input Parmeters:
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* conn - A pointer to the TCP connection structure
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* buffer - A pointer to the buffer to be copied to the read-ahead
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* buffers
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* buflen - The number of bytes to copy to the read-ahead buffer.
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*
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* Returned value:
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* The number of bytes actually buffered. This could be less than 'nbytes'
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* if there is insufficient buffering available.
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*
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* Assumptions:
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* - The caller has checked that UIP_NEWDATA is set in flags and that is no
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* other handler available to process the incoming data.
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* - This function is called at the interrupt level with interrupts disabled.
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*
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****************************************************************************/
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#ifdef CONFIG_NET_TCP_READAHEAD
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uint16_t uip_datahandler(FAR struct uip_conn *conn, FAR uint8_t *buffer,
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uint16_t buflen)
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{
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FAR struct uip_readahead_s *readahead1;
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FAR struct uip_readahead_s *readahead2 = NULL;
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uint16_t remaining;
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uint16_t recvlen = 0;
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/* First, we need to determine if we have space to buffer the data. This
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* needs to be verified before we actually begin buffering the data. We
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* will use any remaining space in the last allocated readahead buffer
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* plus as much one additional buffer. It is expected that the size of
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* readahead buffers are tuned so that one full packet will always fit
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* into one readahead buffer (for example if the buffer size is 420, then
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* a readahead buffer of 366 will hold a full packet of TCP data).
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*/
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readahead1 = (FAR struct uip_readahead_s*)conn->readahead.tail;
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if ((readahead1 &&
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(CONFIG_NET_TCP_READAHEAD_BUFSIZE - readahead1->rh_nbytes) > buflen) ||
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(readahead2 = uip_tcpreadahead_alloc()) != NULL)
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{
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/* We have buffer space. Now try to append add as much data as possible
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* to the last readahead buffer attached to this connection.
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*/
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remaining = buflen;
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if (readahead1)
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{
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recvlen = uip_readahead(readahead1, buffer, remaining);
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if (recvlen > 0)
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{
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buffer += recvlen;
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remaining -= recvlen;
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}
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}
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/* Do we need to buffer into the newly allocated buffer as well? */
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if (readahead2)
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{
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readahead2->rh_nbytes = 0;
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recvlen += uip_readahead(readahead2, buffer, remaining);
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/* Save the readahead buffer in the connection structure where
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* it can be found with recv() is called.
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*/
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sq_addlast(&readahead2->rh_node, &conn->readahead);
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}
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}
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nllvdbg("Buffered %d bytes (of %d)\n", recvlen, buflen);
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return recvlen;
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}
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#endif /* CONFIG_NET_TCP_READAHEAD */
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#endif /* CONFIG_NET && CONFIG_NET_TCP */
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