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- /****************************************************************************
- * net/udp/udp_notifier.c
- *
- * Copyright (C) 2018 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 <assert.h>
- #include <nuttx/wqueue.h>
- #include <nuttx/mm/iob.h>
- #include "udp/udp.h"
- #ifdef CONFIG_UDP_READAHEAD_NOTIFIER
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: udp_notifier_setup
- *
- * Description:
- * Set up to perform a callback to the worker function when an UDP data
- * is added to the read-ahead buffer. The worker function will execute
- * on the low priority worker thread.
- *
- * Input Parameters:
- * worker - The worker function to execute on the low priority work
- * queue when data is available in the UDP read-ahead buffer.
- * conn - The UDP connection where read-ahead data is needed.
- * arg - A user-defined argument that will be available to the worker
- * function when it runs.
- *
- * Returned Value:
- * > 0 - The notification is in place. The returned value is a key that
- * may be used later in a call to udp_notifier_teardown().
- * == 0 - There is already buffered read-ahead data. No notification
- * will be provided.
- * < 0 - An unexpected error occurred and notification will occur. The
- * returned value is a negated errno value that indicates the
- * nature of the failure.
- *
- ****************************************************************************/
- int udp_notifier_setup(worker_t worker, FAR struct udp_conn_s *conn,
- FAR void *arg)
- {
- struct work_notifier_s info;
- DEBUGASSERT(worker != NULL);
- /* If there is already buffered read-ahead data, then return zero without
- * setting up the notification.
- */
- if (conn->readahead.qh_head != NULL)
- {
- return 0;
- }
- /* Otherwise, this is just a simple wrapper around work_notifer_setup(). */
- info.evtype = WORK_UDP_READAHEAD;
- info.qid = LPWORK;
- info.qualifier = conn;
- info.arg = arg;
- info.worker = worker;
- return work_notifier_setup(&info);
- }
- /****************************************************************************
- * Name: udp_notifier_teardown
- *
- * Description:
- * Eliminate a UDP read-ahead notification previously setup by
- * udp_notifier_setup(). This function should only be called if the
- * notification should be aborted prior to the notification. The
- * notification will automatically be torn down after the notification.
- *
- * Input Parameters:
- * key - The key value returned from a previous call to
- * udp_notifier_setup().
- *
- * Returned Value:
- * Zero (OK) is returned on success; a negated errno value is returned on
- * any failure.
- *
- ****************************************************************************/
- int udp_notifier_teardown(int key)
- {
- /* This is just a simple wrapper around work_notifier_teardown(). */
- return work_notifier_teardown(key);
- }
- /****************************************************************************
- * Name: udp_notifier_signal
- *
- * Description:
- * Read-ahead data has been buffered. Notify all threads waiting for
- * read-ahead data to become available.
- *
- * When read-ahead data becomes available, *all* of the workers waiting
- * for read-ahead data will be executed. If there are multiple workers
- * waiting for read-ahead data then only the first to execute will get the
- * data. Others will need to call udp_notifier_setup() once again.
- *
- * Input Parameters:
- * conn - The UDP connection where read-ahead data was just buffered.
- *
- * Returned Value:
- * None.
- *
- ****************************************************************************/
- void udp_notifier_signal(FAR struct udp_conn_s *conn)
- {
- /* This is just a simple wrapper around work_notifier_signal(). */
- return work_notifier_signal(WORK_UDP_READAHEAD, conn);
- }
- #endif /* CONFIG_UDP_READAHEAD_NOTIFIER */
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