nuttx/net/netlink/netlink_conn.c

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/****************************************************************************
* net/netlink/netlink_conn.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 <stdint.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/kmalloc.h>
#include <nuttx/queue.h>
#include <nuttx/mutex.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netlink.h>
#include "utils/utils.h"
#include "netlink/netlink.h"
#ifdef CONFIG_NET_NETLINK
/****************************************************************************
* Private Data
****************************************************************************/
/* The array containing all NetLink connections. */
#if CONFIG_NETLINK_PREALLOC_CONNS > 0
static struct netlink_conn_s
g_netlink_connections[CONFIG_NETLINK_PREALLOC_CONNS];
#endif
/* A list of all free NetLink connections */
static dq_queue_t g_free_netlink_connections;
static mutex_t g_free_lock = NXMUTEX_INITIALIZER;
/* A list of all allocated NetLink connections */
static dq_queue_t g_active_netlink_connections;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: netlink_response_available
*
* Description:
* Handle a Netlink response available notification.
*
* Input Parameters:
* Standard work handler parameters
*
* Returned Value:
* None
*
****************************************************************************/
static void netlink_response_available(FAR void *arg)
{
DEBUGASSERT(arg != NULL);
/* wakeup the waiter */
nxsem_post(arg);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: netlink_initialize()
*
* Description:
* Initialize the NetLink connection structures. Called once and only
* from the networking layer.
*
****************************************************************************/
void netlink_initialize(void)
{
#if CONFIG_NETLINK_PREALLOC_CONNS > 0
int i;
for (i = 0; i < CONFIG_NETLINK_PREALLOC_CONNS; i++)
{
/* Mark the connection closed and move it to the free list */
dq_addlast(&g_netlink_connections[i].sconn.node,
&g_free_netlink_connections);
}
#endif
}
/****************************************************************************
* Name: netlink_alloc()
*
* Description:
* Allocate a new, uninitialized NetLink connection structure. This is
* normally something done by the implementation of the socket() API
*
****************************************************************************/
FAR struct netlink_conn_s *netlink_alloc(void)
{
FAR struct netlink_conn_s *conn;
#if CONFIG_NETLINK_ALLOC_CONNS > 0
int i;
#endif
/* The free list is protected by a mutex. */
nxmutex_lock(&g_free_lock);
#if CONFIG_NETLINK_ALLOC_CONNS > 0
if (dq_peek(&g_free_netlink_connections) == NULL)
{
#if CONFIG_NETLINK_MAX_CONNS > 0
if (dq_count(&g_active_netlink_connections) +
CONFIG_NETLINK_ALLOC_CONNS > CONFIG_NETLINK_MAX_CONNS)
{
nxmutex_unlock(&g_free_lock);
return NULL;
}
#endif
conn = kmm_zalloc(sizeof(*conn) * CONFIG_NETLINK_ALLOC_CONNS);
if (conn != NULL)
{
for (i = 0; i < CONFIG_NETLINK_ALLOC_CONNS; i++)
{
dq_addlast(&conn[i].sconn.node, &g_free_netlink_connections);
}
}
}
#endif
conn = (FAR struct netlink_conn_s *)
dq_remfirst(&g_free_netlink_connections);
if (conn != NULL)
{
/* Enqueue the connection into the active list */
dq_addlast(&conn->sconn.node, &g_active_netlink_connections);
}
nxmutex_unlock(&g_free_lock);
return conn;
}
/****************************************************************************
* Name: netlink_free()
*
* Description:
* Free a NetLink connection structure that is no longer in use. This
* should be done by the implementation of close().
*
****************************************************************************/
void netlink_free(FAR struct netlink_conn_s *conn)
{
FAR sq_entry_t *resp;
/* The free list is protected by a mutex. */
DEBUGASSERT(conn->crefs == 0);
nxmutex_lock(&g_free_lock);
/* Remove the connection from the active list */
dq_rem(&conn->sconn.node, &g_active_netlink_connections);
/* Free any unclaimed responses */
while ((resp = sq_remfirst(&conn->resplist)) != NULL)
{
kmm_free(resp);
}
/* If this is a preallocated or a batch allocated connection store it in
* the free connections list. Else free it.
*/
#if CONFIG_NETLINK_ALLOC_CONNS == 1
if (conn < g_netlink_connections || conn >= (g_netlink_connections +
CONFIG_NETLINK_PREALLOC_CONNS))
{
kmm_free(conn);
}
else
#endif
{
memset(conn, 0, sizeof(*conn));
dq_addlast(&conn->sconn.node, &g_free_netlink_connections);
}
nxmutex_unlock(&g_free_lock);
}
/****************************************************************************
* Name: netlink_nextconn()
*
* Description:
* Traverse the list of allocated NetLink connections
*
* Assumptions:
* This function is called from NetLink device logic.
*
****************************************************************************/
FAR struct netlink_conn_s *netlink_nextconn(FAR struct netlink_conn_s *conn)
{
if (conn == NULL)
{
return (FAR struct netlink_conn_s *)g_active_netlink_connections.head;
}
else
{
return (FAR struct netlink_conn_s *)conn->sconn.node.flink;
}
}
/****************************************************************************
* Name: netlink_add_response
*
* Description:
* Add response data at the tail of the pending response list.
*
* Note: The network will be momentarily locked to support exclusive
* access to the pending response list.
*
* Input Parameters:
* handle - The handle previously provided to the sendto() implementation
* for the protocol. This is an opaque reference to the Netlink
* socket state structure.
* resp - The response to the request. The memory referenced by 'resp'
* must have been allocated via kmm_malloc(). It will be freed
* using kmm_free() after it has been consumed.
*
****************************************************************************/
void netlink_add_response(NETLINK_HANDLE handle,
FAR struct netlink_response_s *resp)
{
FAR struct netlink_conn_s *conn;
conn = handle;
DEBUGASSERT(conn != NULL && resp != NULL);
/* Add the response to the end of the FIFO list */
net_lock();
sq_addlast(&resp->flink, &conn->resplist);
/* Notify any waiters that a response is available */
netlink_notifier_signal(conn);
net_unlock();
}
/****************************************************************************
* Name: netlink_add_broadcast
*
* Description:
* Add broadcast data to all interested netlink connections.
*
* Note: The network will be momentarily locked to support exclusive
* access to the pending response list.
*
* Input Parameters:
* group - The broadcast group index.
* data - The broadcast data. The memory referenced by 'data'
* must have been allocated via kmm_malloc(). It will be freed
* using kmm_free() after it has been consumed.
*
****************************************************************************/
void netlink_add_broadcast(int group, FAR struct netlink_response_s *data)
{
FAR struct netlink_conn_s *conn = NULL;
int first = 1;
DEBUGASSERT(data != NULL);
net_lock();
while ((conn = netlink_nextconn(conn)) != NULL)
{
if ((conn->groups & (1 << (group - 1))) == 0)
{
continue;
}
/* Duplicate the package except the first loop */
if (!first)
{
FAR struct netlink_response_s *tmp;
size_t len;
len = sizeof(sq_entry_t) + data->msg.nlmsg_len;
tmp = kmm_malloc(len);
if (tmp == NULL)
{
break;
}
memcpy(tmp, data, len);
data = tmp;
}
first = 0;
/* Add the response to the end of the FIFO list */
sq_addlast(&data->flink, &conn->resplist);
/* Notify any waiters that a response is available */
netlink_notifier_signal(conn);
}
net_unlock();
/* Drop the package if nobody is interested in */
if (first)
{
kmm_free(data);
}
}
/****************************************************************************
* Name: netlink_tryget_response
*
* Description:
* Return the next response from the head of the pending response list.
* Responses are returned one-at-a-time in FIFO order.
*
* Note: The network will be momentarily locked to support exclusive
* access to the pending response list.
*
* Returned Value:
* The next response from the head of the pending response list is
* returned. NULL will be returned if the pending response list is
* empty
*
****************************************************************************/
FAR struct netlink_response_s *
netlink_tryget_response(FAR struct netlink_conn_s *conn)
{
FAR struct netlink_response_s *resp;
DEBUGASSERT(conn != NULL);
/* Return the response at the head of the pending response list (may be
* NULL).
*/
net_lock();
resp = (FAR struct netlink_response_s *)sq_remfirst(&conn->resplist);
net_unlock();
return resp;
}
/****************************************************************************
* Name: netlink_get_response
*
* Description:
* Return the next response from the head of the pending response list.
* Responses are returned one-at-a-time in FIFO order.
*
* Note: The network will be momentarily locked to support exclusive
* access to the pending response list.
*
* Returned Value:
* The next response from the head of the pending response list is
* returned. This function will block until a response is received if
* the pending response list is empty. NULL will be returned only in the
* event of a failure.
*
****************************************************************************/
FAR struct netlink_response_s *
netlink_get_response(FAR struct netlink_conn_s *conn)
{
FAR struct netlink_response_s *resp;
int ret;
DEBUGASSERT(conn != NULL);
/* Loop, until a response is received. A loop is used because in the case
* of multiple waiters, all waiters will be awakened, but only the highest
* priority waiter will get the response.
*/
net_lock();
while ((resp = netlink_tryget_response(conn)) == NULL)
{
sem_t waitsem;
/* Set up a semaphore to notify us when a response is queued. */
nxsem_init(&waitsem, 0, 0);
/* Set up a notifier to post the semaphore when a response is
* received.
*/
ret = netlink_notifier_setup(netlink_response_available, conn,
&waitsem);
if (ret < 0)
{
nerr("ERROR: netlink_notifier_setup() failed: %d\n", ret);
}
else
{
/* Wait for a response to be queued */
nxsem_post(&waitsem);
}
/* Clean-up the semaphore */
nxsem_destroy(&waitsem);
netlink_notifier_teardown(conn);
/* Check for any failures */
if (ret < 0)
{
break;
}
}
net_unlock();
return resp;
}
/****************************************************************************
* Name: netlink_check_response
*
* Description:
* Return true is a response is pending now.
*
* Returned Value:
* True: A response is available; False; No response is available.
*
****************************************************************************/
bool netlink_check_response(FAR struct netlink_conn_s *conn)
{
DEBUGASSERT(conn != NULL);
/* Check if the response is available. It is not necessary to lock the
* network because the sq_peek() is an atomic operation.
*/
return (sq_peek(&conn->resplist) != NULL);
}
#endif /* CONFIG_NET_NETLINK */