incubator-nuttx/net/netdev/netdev_findbyindex.c

102 lines
3.6 KiB
C

/****************************************************************************
* net/netdev/netdev_findbyindex.c
*
* Copyright (C) 2015 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>
#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
#include <string.h>
#include <errno.h>
#include <nuttx/net/netdev.h>
#include "utils/utils.h"
#include "netdev/netdev.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: netdev_findbyindex
*
* Description:
* Find a previously registered network device by its position in the
* list of registered devices. NOTE that this function is not a safe way
* to enumerate network devices: There could be changes to the list of
* registered device causing a given index to be meaningless (unless, of
* course, the caller keeps the network locked).
*
* Parameters:
* index - the index of the interface to file
*
* Returned Value:
* Pointer to driver on success; NULL on failure. This function can only
* fail if there are fewer registered interfaces than could be indexed.
*
* Assumptions:
* Called from normal user mode
*
****************************************************************************/
FAR struct net_driver_s *netdev_findbyindex(int index)
{
#ifdef CONFIG_NETDEV_MULTINIC
FAR struct net_driver_s *dev;
net_lock_t save;
int i;
save = net_lock();
for (i = 0, dev = g_netdevices; dev; i++, dev = dev->flink)
{
if (i == index)
{
net_unlock(save);
return dev;
}
}
net_unlock(save);
return NULL;
#else
return (index == 0) ? g_netdevices : NULL;
#endif
}
#endif /* CONFIG_NET && CONFIG_NSOCKET_DESCRIPTORS */