/****************************************************************************
* net/tcp/tcp_callback.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <string.h>
#include <debug.h>
#include <assert.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"
#include "utils/utils.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 recvlen;
/* 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
*/
flags = (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)
{
ninfo("No listener on connection\n");
/* Save as the packet data as in the read-ahead buffer. NOTE that
* partial packets will not be buffered.
*/
recvlen = tcp_datahandler(dev, conn,
(dev->d_appdata - dev->d_iob->io_data) -
dev->d_iob->io_offset);
net_incr32(conn->rcvseq, recvlen);
}
/* In any event, the new data has now been handled */
dev->d_len = 0;
return flags;
}
/****************************************************************************
* Name: tcp_ofoseg_data_event
*
* Description:
* Handle out-of-order segment to readahead poll.
*
* Assumptions:
* - This function must be called with the network locked.
*
****************************************************************************/
#ifdef CONFIG_NET_TCP_OUT_OF_ORDER
static uint16_t tcp_ofoseg_data_event(FAR struct net_driver_s *dev,
FAR struct tcp_conn_s *conn,
uint16_t flags)
{
FAR struct tcp_ofoseg_s *seg;
uint32_t rcvseq;
int i = 0;
/* 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
*/
flags |= TCP_SNDACK;
/* Get the receive sequence number */
rcvseq = tcp_getsequence(conn->rcvseq);
ninfo("TCP OFOSEG rcvseq [%" PRIu32 "]\n", rcvseq);
/* Foreach out-of-order segments */
while (i < conn->nofosegs)
{
seg = &conn->ofosegs[i];
/* rcvseq -->|
* ofoseg |------|
*/
if (rcvseq == seg->left)
{
ninfo("TCP OFOSEG input [%" PRIu32 " : %" PRIu32 " : %u]\n",
seg->left, seg->right, seg->data->io_pktlen);
rcvseq = TCP_SEQ_ADD(rcvseq,
seg->data->io_pktlen);
net_incr32(conn->rcvseq, seg->data->io_pktlen);
net_iob_concat(&conn->readahead, &seg->data);
}
else if (TCP_SEQ_GT(rcvseq, seg->left))
{
/* rcvseq -->|
* ofoseg |------|
*/
if (TCP_SEQ_GTE(rcvseq, seg->right))
{
/* Remove stale segments */
iob_free_chain(seg->data);
seg->data = NULL;
}
/* rcvseq -->|
* ofoseg |------|
*/
else
{
seg->data =
iob_trimhead(seg->data,
TCP_SEQ_SUB(rcvseq, seg->left));
seg->left = rcvseq;
if (seg->data != NULL)
{
ninfo("TCP OFOSEG input "
"[%" PRIu32 " : %" PRIu32 " : %u]\n",
seg->left, seg->right, seg->data->io_pktlen);
rcvseq = TCP_SEQ_ADD(rcvseq,
seg->data->io_pktlen);
net_incr32(conn->rcvseq, seg->data->io_pktlen);
net_iob_concat(&conn->readahead, &seg->data);
}
}
}
/* Rebuild out-of-order pool if segment is consumed */
if (seg->data == NULL)
{
for (; i < conn->nofosegs - 1; i++)
{
conn->ofosegs[i] = conn->ofosegs[i + 1];
}
conn->nofosegs--;
/* Try segments again */
i = 0;
}
else
{
i++;
}
}
return flags;
}
#endif /* CONFIG_NET_TCP_OUT_OF_ORDER */
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: tcp_ofoseg_bufsize
*
* Description:
* Calculate the pending size of out-of-order buffer
*
* Input Parameters:
* conn - The TCP connection of interest
*
* Returned Value:
* Total size of out-of-order buffer
*
* Assumptions:
* This function must be called with the network locked.
*
****************************************************************************/
#ifdef CONFIG_NET_TCP_OUT_OF_ORDER
int tcp_ofoseg_bufsize(FAR struct tcp_conn_s *conn)
{
int total = 0;
int i;
for (i = 0; i < conn->nofosegs; i++)
{
total += conn->ofosegs[i].data->io_pktlen;
}
return total;
}
#endif /* CONFIG_NET_TCP_OUT_OF_ORDER */
/****************************************************************************
* 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)
{
#if defined(CONFIG_NET_TCP_NOTIFIER) || defined(CONFIG_NET_TCP_OUT_OF_ORDER)
uint16_t orig = flags;
#endif
/* Prepare device buffer */
if (dev->d_iob == NULL && netdev_iob_prepare(dev, false, 0) != OK)
{
return 0;
}
/* 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, flags, conn->sconn.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);
}
#ifdef CONFIG_NET_TCP_OUT_OF_ORDER
if ((orig & TCP_NEWDATA) != 0 && conn->nofosegs > 0)
{
/* Try out-of-order pool if new data is coming */
flags = tcp_ofoseg_data_event(dev, conn, flags);
}
#endif
/* 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, 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
/* Re-prepare the device buffer if d_iob is consumed by the stack */
if (dev->d_iob == NULL)
{
netdev_iob_prepare(dev, false, 0);
}
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.
*
****************************************************************************/
uint16_t tcp_datahandler(FAR struct net_driver_s *dev,
FAR struct tcp_conn_s *conn,
uint16_t offset)
{
FAR struct iob_s *iob = dev->d_iob;
uint16_t buflen;
if (offset > 0)
{
/* Remove 'bufoff' bytes from the beginning of the input I/O chain */
iob = iob_trimhead(iob, offset);
}
/* Trim tail if l3/l4 header has been removed */
if (dev->d_len < iob->io_pktlen)
{
iob = iob_trimtail(iob, iob->io_pktlen - dev->d_len);
}
buflen = iob->io_pktlen;
/* Concat the iob to readahead */
net_iob_concat(&conn->readahead, &iob);
/* Clear device buffer */
netdev_iob_clear(dev);
#ifdef CONFIG_NET_TCP_NOTIFIER
/* Provide notification(s) that additional TCP read-ahead data is
* available.
*/
tcp_readahead_signal(conn);
#endif
ninfo("Buffered %" PRIu16 " bytes\n", buflen);
return buflen;
}
#endif /* NET_TCP_HAVE_STACK */