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px4-firmware/nuttx/net/net_sockets.c

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/****************************************************************************
* net/net_sockets.c
*
* Copyright (C) 2007-2009, 2011-2012 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>
#ifdef CONFIG_NET
#include <string.h>
#include <semaphore.h>
#include <assert.h>
#include <sched.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/net/uip/uip.h>
#include <nuttx/net/net.h>
#include <nuttx/kmalloc.h>
#include "net_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Public Types
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
#if CONFIG_NSOCKET_DESCRIPTORS > 0
static void _net_semtake(FAR struct socketlist *list)
{
/* Take the semaphore (perhaps waiting) */
while (uip_lockedwait(&list->sl_sem) != 0)
{
/* The only case that an error should occr here is if
* the wait was awakened by a signal.
*/
ASSERT(*get_errno_ptr() == EINTR);
}
}
# define _net_semgive(list) sem_post(&list->sl_sem)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/* This is called from the initialization logic to configure the socket layer */
void net_initialize(void)
{
/* Initialize the uIP layer */
uip_initialize();
/* Initialize the socket layer */
#if CONFIG_NSOCKET_DESCRIPTORS > 0
sem_init(&g_netdev_sem, 0, 1);
#endif
/* Initialize the periodic ARP timer */
arptimer_init();
}
#if CONFIG_NSOCKET_DESCRIPTORS > 0
/* Allocate a list of files for a new task */
FAR struct socketlist *net_alloclist(void)
{
FAR struct socketlist *list;
list = (FAR struct socketlist*)kzalloc(sizeof(struct socketlist));
if (list)
{
/* Start with a reference count of one */
list->sl_crefs = 1;
/* Initialize the list access mutex */
(void)sem_init(&list->sl_sem, 0, 1);
}
return list;
}
/* Increase the reference count on a file list */
int net_addreflist(FAR struct socketlist *list)
{
if (list)
{
/* Increment the reference count on the list.
* NOTE: that we disable interrupts to do this
* (vs. taking the list semaphore). We do this
* because file cleanup operations often must be
* done from the IDLE task which cannot wait
* on semaphores.
*/
register uip_lock_t flags = uip_lock();
list->sl_crefs++;
uip_unlock(flags);
}
return OK;
}
/* Release a reference to the file list */
int net_releaselist(FAR struct socketlist *list)
{
int crefs;
int ndx;
if (list)
{
/* Decrement the reference count on the list.
* NOTE: that we disable interrupts to do this
* (vs. taking the list semaphore). We do this
* because file cleanup operations often must be
* done from the IDLE task which cannot wait
* on semaphores.
*/
uip_lock_t flags = uip_lock();
crefs = --(list->sl_crefs);
uip_unlock(flags);
/* If the count decrements to zero, then there is no reference
* to the structure and it should be deallocated. Since there
* are references, it would be an error if any task still held
* a reference to the list's semaphore.
*/
if (crefs <= 0)
{
/* Close each open socket in the list
* REVISIT: psock_close() will attempt to use semaphores.
* If we actually are in the IDLE thread, then could this cause
* problems? Probably not, if the task has exited and crefs is
* zero, then there probably could not be a contender for the
* semaphore.
*/
for (ndx = 0; ndx < CONFIG_NSOCKET_DESCRIPTORS; ndx++)
{
FAR struct socket *psock = &list->sl_sockets[ndx];
if (psock->s_crefs > 0)
{
(void)psock_close(psock);
}
}
/* Destroy the semaphore and release the filelist */
(void)sem_destroy(&list->sl_sem);
sched_free(list);
}
}
return OK;
}
int sockfd_allocate(int minsd)
{
FAR struct socketlist *list;
int i;
/* Get the socket list for this task/thread */
list = sched_getsockets();
if (list)
{
/* Search for a socket structure with no references */
_net_semtake(list);
for (i = minsd; i < CONFIG_NSOCKET_DESCRIPTORS; i++)
{
/* Are there references on this socket? */
if (!list->sl_sockets[i].s_crefs)
{
/* No take the reference and return the index + an offset
* as the socket descriptor.
*/
memset(&list->sl_sockets[i], 0, sizeof(struct socket));
list->sl_sockets[i].s_crefs = 1;
_net_semgive(list);
return i + __SOCKFD_OFFSET;
}
}
_net_semgive(list);
}
return ERROR;
}
void sock_release(FAR struct socket *psock)
{
#if CONFIG_DEBUG
if (psock)
#endif
{
/* Take the list semaphore so that there will be no accesses
* to this socket structure.
*/
FAR struct socketlist *list = sched_getsockets();
if (list)
{
/* Decrement the count if there the socket will persist
* after this.
*/
_net_semtake(list);
if (psock && psock->s_crefs > 1)
{
psock->s_crefs--;
}
else
{
/* The socket will not persist... reset it */
memset(psock, 0, sizeof(struct socket));
}
_net_semgive(list);
}
}
}
void sockfd_release(int sockfd)
{
/* Get the socket structure for this sockfd */
FAR struct socket *psock = sockfd_socket(sockfd);
/* Get the socket structure for this sockfd */
if (psock)
{
sock_release(psock);
}
}
FAR struct socket *sockfd_socket(int sockfd)
{
FAR struct socketlist *list;
int ndx = sockfd - __SOCKFD_OFFSET;
if (ndx >=0 && ndx < CONFIG_NSOCKET_DESCRIPTORS)
{
list = sched_getsockets();
if (list)
{
return &list->sl_sockets[ndx];
}
}
return NULL;
}
#endif /* CONFIG_NSOCKET_DESCRIPTORS */
#endif /* CONFIG_NET */
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