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incubator-nuttx/net/tcp/tcp_callback.c

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/****************************************************************************
* net/tcp/tcp_callback.c
*
* Copyright (C) 2007-2009, 2014, 2017 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>
#include <stdint.h>
#include <string.h>
#include <debug.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/netstats.h>
#include "devif/devif.h"
#include "tcp/tcp.h"
#ifdef NET_TCP_HAVE_STACK
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_data_event
*
* 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 TCP_NEWDATA is set in flags and that is no
* other handler available to process the incoming data.
* - This function must be called with the network locked.
*
****************************************************************************/
static inline uint16_t
tcp_data_event(FAR struct net_driver_s *dev, FAR struct tcp_conn_s *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 & ~TCP_NEWDATA) | TCP_SNDACK;
/* Is there new data? With non-zero length? (Certain connection events
* can have zero-length with TCP_NEWDATA set just to cause an ACK).
*/
if (dev->d_len > 0)
{
#ifdef CONFIG_NET_TCP_READAHEAD
uint8_t *buffer = dev->d_appdata;
int buflen = dev->d_len;
uint16_t recvlen;
#endif
ninfo("No listener on connection\n");
#ifdef CONFIG_NET_TCP_READAHEAD
/* Save as the packet data as in the read-ahead buffer. NOTE that
* partial packets will not be buffered.
*/
recvlen = tcp_datahandler(conn, buffer, buflen);
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.
*/
ninfo("Dropped %d bytes\n", dev->d_len);
#ifdef CONFIG_NET_STATISTICS
g_netstats.tcp.drop++;
#endif
/* Clear the TCP_SNDACK bit so that no ACK will be sent */
ret &= ~TCP_SNDACK;
}
}
/* In any event, the new data has now been handled */
dev->d_len = 0;
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_callback
*
* Description:
* Inform the application holding the TCP socket of a change in state.
*
* Assumptions:
* This function must be called with the network locked.
*
****************************************************************************/
uint16_t tcp_callback(FAR struct net_driver_s *dev,
FAR struct tcp_conn_s *conn, uint16_t flags)
{
#ifdef CONFIG_NET_TCP_NOTIFIER
uint16_t orig = flags;
#endif
/* Preserve the TCP_ACKDATA, TCP_CLOSE, and TCP_ABORT in the response.
* These is needed by the network to handle responses and buffer state. The
* TCP_NEWDATA indication will trigger the ACK response, but must be
* explicitly set in the callback.
*/
ninfo("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:
*
* TCP_CLOSE - Gracefully close the current connection
* TCP_ABORT - Abort (reset) the current connection on an error that
* prevents TCP_CLOSE from working.
*
* And/Or set/clear the following:
*
* TCP_NEWDATA - May be cleared to indicate that the data was consumed
* and that no further process of the new data should be
* attempted.
* TCP_SNDACK - If TCP_NEWDATA is cleared, then TCP_SNDACK may be set
* to indicate that an ACK should be included in the
* response. (In TCP_NEWDATA is cleared but TCP_SNDACK is
* not set, then dev->d_len should also be cleared).
*/
flags = devif_conn_event(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 ((flags & TCP_NEWDATA) != 0)
{
/* Data was not handled.. dispose of it appropriately */
flags = tcp_data_event(dev, conn, flags);
}
/* Check if there is a connection-related event and a connection
* callback.
*/
if ((flags & TCP_CONN_EVENTS) != 0)
{
/* Perform the callback disconnect callbacks */
flags = devif_conn_event(dev, conn, flags, conn->connevents);
}
#ifdef CONFIG_NET_TCP_NOTIFIER
/* Provide notification(s) if the TCP connection has been lost. */
if ((orig & TCP_DISCONN_EVENTS) != 0)
{
tcp_disconnect_signal(conn);
}
#endif
return flags;
}
/****************************************************************************
* Name: tcp_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 Parameters:
* 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 is returned. This will be either
* zero or equal to buflen; partial packets are not buffered.
*
* Assumptions:
* - The caller has checked that TCP_NEWDATA is set in flags and that is no
* other handler available to process the incoming data.
* - This function must be called with the network locked.
*
****************************************************************************/
#ifdef CONFIG_NET_TCP_READAHEAD
uint16_t tcp_datahandler(FAR struct tcp_conn_s *conn, FAR uint8_t *buffer,
uint16_t buflen)
{
FAR struct iob_s *iob;
int ret;
/* Try to allocate on I/O buffer to start the chain without waiting (and
* throttling as necessary). If we would have to wait, then drop the
* packet.
*/
iob = iob_tryalloc(true, IOBUSER_NET_TCP_READAHEAD);
if (iob == NULL)
{
nerr("ERROR: Failed to create new I/O buffer chain\n");
return 0;
}
/* Copy the new appdata into the I/O buffer chain (without waiting) */
ret = iob_trycopyin(iob, buffer, buflen, 0, true,
IOBUSER_NET_TCP_READAHEAD);
if (ret < 0)
{
/* On a failure, iob_copyin return a negated error value but does
* not free any I/O buffers.
*/
nerr("ERROR: Failed to add data to the I/O buffer chain: %d\n", ret);
iob_free_chain(iob, IOBUSER_NET_TCP_READAHEAD);
return 0;
}
/* Add the new I/O buffer chain to the tail of the read-ahead queue (again
* without waiting).
*/
ret = iob_tryadd_queue(iob, &conn->readahead);
if (ret < 0)
{
nerr("ERROR: Failed to queue the I/O buffer chain: %d\n", ret);
iob_free_chain(iob, IOBUSER_NET_TCP_READAHEAD);
return 0;
}
#ifdef CONFIG_NET_TCP_NOTIFIER
/* Provide notification(s) that additional TCP read-ahead data is
* available.
*/
tcp_readahead_signal(conn);
#endif
ninfo("Buffered %d bytes\n", buflen);
return buflen;
}
#endif /* CONFIG_NET_TCP_READAHEAD */
#endif /* NET_TCP_HAVE_STACK */
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