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incubator-nuttx/net/devif/devif_callback.c

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/****************************************************************************
* net/devif/devif_callback.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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>
#if defined(CONFIG_NET)
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <debug.h>
#include <assert.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define DEVIF_CB_DONT_FREE (1 << 0)
#define DEVIF_CB_PEND_FREE (1 << 1)
/****************************************************************************
* Private Data
****************************************************************************/
#if CONFIG_NET_PREALLOC_DEVIF_CALLBACKS > 0
static struct devif_callback_s
g_cbprealloc[CONFIG_NET_PREALLOC_DEVIF_CALLBACKS];
#endif
static FAR struct devif_callback_s *g_cbfreelist = NULL;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: devif_callback_free
*
* Description:
* Return a callback container to the free list.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
static void devif_callback_free(FAR struct net_driver_s *dev,
FAR struct devif_callback_s *cb,
FAR struct devif_callback_s **list_head,
FAR struct devif_callback_s **list_tail)
{
FAR struct devif_callback_s *prev;
FAR struct devif_callback_s *curr;
if (cb)
{
net_lock();
#ifdef CONFIG_DEBUG_FEATURES
/* Check for double freed callbacks */
curr = g_cbfreelist;
while (curr != NULL)
{
DEBUGASSERT(cb != curr);
curr = curr->nxtconn;
}
#endif
/* Remove the callback structure from the data notification list if
* it is supposed to be in the data notification list.
*/
if (list_head)
{
prev = cb->prevconn;
/* Remove the structure from the connection event list */
if (prev)
{
/* The item to be removed is not in the head. */
prev->nxtconn = cb->nxtconn;
if (cb->nxtconn)
{
/* The item to be removed is not in the tail. */
cb->nxtconn->prevconn = prev;
}
}
else
{
/* The item to be removed is in the head. */
*list_head = cb->nxtconn;
if (cb->nxtconn)
{
/* There are more items besides the head item. */
cb->nxtconn->prevconn = NULL;
}
}
if (!cb->nxtconn)
{
/* If the tail item is being removed,
* update the tail pointer.
*/
DEBUGASSERT(list_tail);
*list_tail = prev;
}
}
/* check if the callback structure has DEVIF_CB_DONT_FREE,it indicates
* the callback can't be free immediately,setting DEVIF_CB_PEND_FREE
* flag with the callback,it indicates the callback will be free
* finally
*/
if (cb->free_flags & DEVIF_CB_DONT_FREE)
{
cb->free_flags |= DEVIF_CB_PEND_FREE;
net_unlock();
return;
}
/* Remove the callback structure from the device notification list if
* it is supposed to be in the device notification list.
*/
if (dev != NULL)
{
/* Find the callback structure in the device event list */
for (prev = NULL, curr = dev->d_devcb;
curr != NULL && curr != cb;
prev = curr, curr = curr->nxtdev)
{
}
/* Remove the structure from the device event list */
if (curr != NULL)
{
if (prev)
{
prev->nxtdev = cb->nxtdev;
}
else
{
dev->d_devcb = cb->nxtdev;
}
}
}
/* If this is a preallocated or a batch allocated callback store it in
* the free callbacks list. Else free it.
*/
#if CONFIG_NET_ALLOC_DEVIF_CALLBACKS == 1
if (cb < g_cbprealloc || cb >= (g_cbprealloc +
CONFIG_NET_PREALLOC_DEVIF_CALLBACKS))
{
kmm_free(cb);
}
else
#endif
{
cb->nxtconn = g_cbfreelist;
cb->nxtdev = NULL;
g_cbfreelist = cb;
}
net_unlock();
}
}
/****************************************************************************
* Name: devif_event_trigger
*
* Description:
* Return true if the current set of events should trigger a callback to
* occur.
*
* Input Parameters:
* events - The set of events that has occurred.
* triggers - The set of events that will trigger a callback.
*
****************************************************************************/
static bool devif_event_trigger(uint16_t events, uint16_t triggers)
{
/* The events are divided into a set of individual bits that may be ORed
* together PLUS a field that encodes a single poll event.
*
* First check if any of the individual event bits will trigger the
* callback.
*/
if ((events & triggers & ~DEVPOLL_MASK) != 0)
{
return true;
}
/* No... check the encoded device event. */
if ((events & DEVPOLL_MASK) == (triggers & DEVPOLL_MASK))
{
return (triggers & DEVPOLL_MASK) != 0;
}
/* No.. this event set will not generate the callback */
return false;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: devif_callback_init
*
* Description:
* Configure the pre-allocated callback structures into a free list.
*
* Assumptions:
* Called early in the initialization sequence so that no special
* protection is required.
*
****************************************************************************/
void devif_callback_init(void)
{
#if CONFIG_NET_PREALLOC_DEVIF_CALLBACKS > 0
int i;
for (i = 0; i < CONFIG_NET_PREALLOC_DEVIF_CALLBACKS; i++)
{
g_cbprealloc[i].nxtconn = g_cbfreelist;
g_cbfreelist = &g_cbprealloc[i];
}
#endif
}
/****************************************************************************
* Name: devif_callback_alloc
*
* Description:
* Allocate a callback container from the free list.
*
* If dev is non-NULL, then this function verifies that the device
* reference is still valid and that the device is still UP status. If
* those conditions are not true, this function will fail to allocate the
* callback.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
FAR struct devif_callback_s *
devif_callback_alloc(FAR struct net_driver_s *dev,
FAR struct devif_callback_s **list_head,
FAR struct devif_callback_s **list_tail)
{
FAR struct devif_callback_s *ret;
#if CONFIG_NET_ALLOC_DEVIF_CALLBACKS > 0
int i;
#endif
net_lock();
/* Verify that the device pointer is valid, i.e., that it still
* points to a registered network device and also that the network
* device in the UP state.
*/
/* Note: dev->d_flags may be asynchronously changed by netdev_ifdown()
* (in net/netdev/netdev_ioctl.c). Nevertheless, net_lock() / net_unlock()
* are not required in netdev_ifdown() to prevent dev->d_flags from
* asynchronous change here. There is not an issue because net_lock() and
* net_unlock() present inside of devif_dev_event(). That should be enough
* to de-allocate connection callbacks reliably on NETDEV_DOWN event.
*/
if (dev && !(netdev_verify(dev) && (dev->d_flags & IFF_UP) != 0))
{
net_unlock();
return NULL;
}
/* Allocate the callback entry from heap */
#if CONFIG_NET_ALLOC_DEVIF_CALLBACKS > 0
if (g_cbfreelist == NULL)
{
ret = kmm_zalloc(sizeof(struct devif_callback_s) *
CONFIG_NET_ALLOC_DEVIF_CALLBACKS);
if (ret != NULL)
{
for (i = 0; i < CONFIG_NET_ALLOC_DEVIF_CALLBACKS; i++)
{
ret[i].nxtconn = g_cbfreelist;
g_cbfreelist = &ret[i];
}
}
}
#endif
/* Check the head of the free list */
ret = g_cbfreelist;
if (ret)
{
/* Remove the next instance from the head of the free list */
g_cbfreelist = ret->nxtconn;
memset(ret, 0, sizeof(struct devif_callback_s));
/* Add the newly allocated instance to the head of the device event
* list.
*/
if (dev)
{
ret->nxtdev = dev->d_devcb;
dev->d_devcb = ret;
}
/* Add the newly allocated instance to the tail of the specified list */
if (list_head && list_tail)
{
ret->nxtconn = NULL;
ret->prevconn = *list_tail;
if (*list_tail)
{
/* If the list is not empty, add the item to the tail. */
(*list_tail)->nxtconn = ret;
}
else
{
/* If the list is empty, add the first item to the list. */
*list_head = ret;
}
/* Update the tail pointer */
*list_tail = ret;
}
}
#ifdef CONFIG_DEBUG_FEATURES
else
{
nerr("ERROR: Failed to allocate callback\n");
}
#endif
net_unlock();
return ret;
}
/****************************************************************************
* Name: devif_conn_callback_free
*
* Description:
* Return a connection/port callback container to the free list.
*
* This function is just a front-end for devif_callback_free(). If the
* dev argument is non-NULL, it will verify that the device reference is
* still valid before attempting to free the callback structure. A
* non-NULL list pointer is assumed to be valid in any case.
*
* The callback structure will be freed in any event.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
void devif_conn_callback_free(FAR struct net_driver_s *dev,
FAR struct devif_callback_s *cb,
FAR struct devif_callback_s **list_head,
FAR struct devif_callback_s **list_tail)
{
/* Check if the device pointer is still valid. It could be invalid if, for
* example, the device were unregistered between the time when the callback
* was allocated and the time when the callback was freed.
*/
if (dev && !netdev_verify(dev))
{
/* The device reference is longer valid */
dev = NULL;
}
/* Then free the callback */
devif_callback_free(dev, cb, list_head, list_tail);
}
/****************************************************************************
* Name: devif_dev_callback_free
*
* Description:
* Return a device callback container to the free list.
*
* This function is just a front-end for devif_callback_free(). If the
* de argument is non-NULL, it will verify that the device reference is
* still valid before attempting to free the callback structure. It
* differs from devif_conn_callback_free in that connection/port-related
* connections are also associated with the device and, hence, also will
* not be valid if the device pointer is not valid.
*
* The callback structure will be freed in any event.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
void devif_dev_callback_free(FAR struct net_driver_s *dev,
FAR struct devif_callback_s *cb)
{
FAR struct devif_callback_s **list_head;
FAR struct devif_callback_s **list_tail;
/* Check if the device pointer is still valid. It could be invalid if, for
* example, the device were unregistered between the time when the callback
* was allocated and the time when the callback was freed.
*/
if (dev != NULL && netdev_verify(dev))
{
/* The device reference is valid. Then use the list pointer in the
* device structure as well.
*/
list_head = &dev->d_conncb;
list_tail = &dev->d_conncb_tail;
}
else
{
/* The device reference is longer valid */
dev = NULL;
list_head = NULL;
list_tail = NULL;
}
/* Then free the callback */
devif_callback_free(dev, cb, list_head, list_tail);
}
/****************************************************************************
* Name: devif_conn_event
*
* Description:
* Execute a list of callbacks using the packet event chain.
*
* Input Parameters:
* dev - The network device state structure associated with the network
* device that initiated the callback event.
* flags - The bit set of events to be notified.
* list - The list to traverse in performing the notifications
*
* Returned Value:
* The updated flags as modified by the callback functions.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
uint16_t devif_conn_event(FAR struct net_driver_s *dev, uint16_t flags,
FAR struct devif_callback_s *list)
{
FAR struct devif_callback_s *next;
/* Loop for each callback in the list and while there are still events
* set in the flags set.
*/
net_lock();
while (list && flags)
{
/* Save the pointer to the next callback in the lists. This is done
* because the callback action might delete the entry pointed to by
* list.
*/
next = list->nxtconn;
/* Check if this callback handles any of the events in the flag set */
if (list->event != NULL && devif_event_trigger(flags, list->flags))
{
/* Yes.. perform the callback. Actions perform by the callback
* may delete the current list entry or add a new list entry to
* beginning of the list (which will be ignored on this pass)
*/
flags = list->event(dev, list->priv, flags);
}
/* Set up for the next time through the loop */
list = next;
}
net_unlock();
return flags;
}
/****************************************************************************
* Name: devif_dev_event
*
* Description:
* Execute a list of callbacks using the device event chain.
*
* Input Parameters:
* dev - The network device state structure associated with the network
* device that initiated the callback event.
* flags - The bit set of events to be notified.
*
* Returned Value:
* The updated flags as modified by the callback functions.
*
* Assumptions:
* This function is called with the network locked.
*
****************************************************************************/
uint16_t devif_dev_event(FAR struct net_driver_s *dev, uint16_t flags)
{
FAR struct devif_callback_s *cb;
FAR struct devif_callback_s *next;
/* Loop for each callback in the list and while there are still events
* set in the flags set.
*/
net_lock();
for (cb = dev->d_devcb; cb != NULL && flags != 0; cb = next)
{
/* Save the pointer to the next callback in the lists. This is done
* because the callback action might delete the entry pointed to by
* list.
*/
next = cb->nxtdev;
/* Check if this callback handles any of the events in the flag set */
if (cb->event != NULL && devif_event_trigger(flags, cb->flags))
{
cb->free_flags |= DEVIF_CB_DONT_FREE;
/* Yes.. perform the callback. Actions perform by the callback
* may delete the current list entry or add a new list entry to
* beginning of the list (which will be ignored on this pass)
*/
flags = cb->event(dev, cb->priv, flags);
cb->free_flags &= ~DEVIF_CB_DONT_FREE;
/* update the next callback to prevent previously recorded the
* next callback from being deleted
*/
next = cb->nxtdev;
if ((cb->free_flags & DEVIF_CB_PEND_FREE) != 0)
{
cb->free_flags &= ~DEVIF_CB_PEND_FREE;
devif_callback_free(dev, cb, NULL, NULL);
}
}
}
net_unlock();
return flags;
}
#endif /* CONFIG_NET */
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