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px4-firmware/nuttx/net/uip/uip_tcpcallback.c

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