incubator-nuttx/net/tcp/tcp_txdrain.c

165 lines
4.9 KiB
C

/****************************************************************************
* net/tcp/tcp_txdrain.c
*
* 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 <sys/types.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/net/net.h>
#include <nuttx/semaphore.h>
#include "utils/utils.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_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);
/* 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_sem_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 */