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- /****************************************************************************
- * net/tcp/tcp_txdrain.c
- *
- * Copyright (C) 2019 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 <sys/types.h>
- #include <sched.h>
- #include <assert.h>
- #include <errno.h>
- #include <nuttx/semaphore.h>
- #include "tcp/tcp.h"
- #if defined(CONFIG_NET_TCP_WRITE_BUFFERS) && defined(CONFIG_NET_TCP_NOTIFIER)
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: txdrain_worker
- *
- * Description:
- * Called with the write buffers have all been sent.
- *
- * Input Parameters:
- * arg - The notifier entry.
- *
- * Returned Value:
- * None.
- *
- ****************************************************************************/
- static void txdrain_worker(FAR void *arg)
- {
- FAR sem_t *waitsem = (FAR sem_t *)arg;
- DEBUGASSERT(waitsem != NULL);
- /* Then just post the semaphore, waking up tcp_txdrain() */
- nxsem_post(waitsem);
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: tcp_txdrain
- *
- * Description:
- * Wait for all write buffers to be sent (or for a timeout to occur).
- *
- * Input Parameters:
- * psock - An instance of the internal socket structure.
- * timeout - The relative time when the timeout will occur
- *
- * Returned Value:
- * Zero (OK) is returned on success; a negated errno value is returned
- * on any failure.
- *
- ****************************************************************************/
- int tcp_txdrain(FAR struct socket *psock, unsigned int timeout)
- {
- FAR struct tcp_conn_s *conn;
- sem_t waitsem;
- int ret;
- DEBUGASSERT(psock != NULL && psock->s_crefs > 0 && psock->s_conn != NULL);
- DEBUGASSERT(psock->s_type == SOCK_STREAM);
- conn = (FAR struct tcp_conn_s *)psock->s_conn;
- /* Initialize the wait semaphore */
- nxsem_init(&waitsem, 0, 0);
- nxsem_set_protocol(&waitsem, SEM_PRIO_NONE);
- /* The following needs to be done with the network stable */
- net_lock();
- /* Get a notification when the write buffers are drained */
- ret = tcp_writebuffer_notifier_setup(txdrain_worker, conn, &waitsem);
- /* The special return value of 0 means that there is no Tx data to be
- * drained. Otherwise it is a special 'key' that can be used to teardown
- * the notification later
- */
- if (ret > 0)
- {
- /* Save the drain key */
- int drain_key = ret;
- /* Also get a notification if we lose the connection.
- * REVISIT: This really should not be necessary. tcp_send() should
- * detect the disconnection event and signal the txdrain but I do not
- * see that TCP disconnection event. This assures that the txdrain
- * operation will not wait for the full timeout in that case.
- */
- ret = tcp_disconnect_notifier_setup(txdrain_worker, conn, &waitsem);
- /* Zero is a special value that means that no connection has been
- * established. Otherwise it is a special 'key' that can be used
- * to teardown the notification later
- */
- if (ret > 0)
- {
- /* Save the disconnect key */
- int disconn_key = ret;
- /* There is pending write data and the socket is connected..
- * wait for it to drain or be be disconnected.
- */
- ret = net_timedwait_uninterruptible(&waitsem, timeout);
- /* Tear down the disconnect notifier */
- tcp_notifier_teardown(disconn_key);
- }
- /* Tear down the disconnect notifier */
- tcp_notifier_teardown(drain_key);
- }
- net_unlock();
- nxsem_destroy(&waitsem);
- return ret;
- }
- #endif /* CONFIG_NET_TCP_WRITE_BUFFERS && CONFIG_NET_TCP_NOTIFIER */
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