nuttx/net/netlink/netlink.h
Michael Jung f208c4bbd4 Fix ENOENT errors when polling on Netlink socket
When a Netlink response is issued, which a task is currently polling for
on the corresponding AF_NETLINK socket, then the poll call will return
with a ENOENT error.  This is due to the fact that the Netlink response
notifier is automatically torn down after the notification.

Fixed by making netlink_notifier_teardown a best-effort function that
does not return a result code.

Signed-off-by: Michael Jung <michael.jung@secore.ly>
2022-05-14 00:35:29 +03:00

289 lines
9.8 KiB
C

/****************************************************************************
* net/netlink/netlink.h
*
* 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.
*
****************************************************************************/
#ifndef __NET_NETLINK_NETLINK_H
#define __NET_NETLINK_NETLINK_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <queue.h>
#include <poll.h>
#include <netpacket/netlink.h>
#include <nuttx/net/netlink.h>
#include <nuttx/semaphore.h>
#include <nuttx/wqueue.h>
#include "devif/devif.h"
#include "socket/socket.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef CONFIG_NETLINK_ROUTE
#define netlink_device_notify(dev)
#endif
#ifdef CONFIG_NET_NETLINK
/****************************************************************************
* Public Type Definitions
****************************************************************************/
/* This connection structure describes the underlying state of the socket. */
struct netlink_conn_s
{
/* Common prologue of all connection structures. */
struct socket_conn_s sconn;
/* NetLink-specific content follows */
uint32_t pid; /* Port ID (if bound) */
uint32_t groups; /* Multicast groups mask (if bound) */
uint32_t dst_pid; /* Destination port ID */
uint32_t dst_groups; /* Destination multicast groups mask */
uint8_t crefs; /* Reference counts on this instance */
uint8_t protocol; /* See NETLINK_* definitions */
/* poll() support */
int key; /* used to cancel notifications */
FAR sem_t *pollsem; /* Used to wakeup poll() */
FAR pollevent_t *pollevent; /* poll() wakeup event */
/* Queued response data */
sq_queue_t resplist; /* Singly linked list of responses */
};
/****************************************************************************
* Public Data
****************************************************************************/
#ifdef __cplusplus
# define EXTERN extern "C"
extern "C"
{
#else
# define EXTERN extern
#endif
EXTERN const struct sock_intf_s g_netlink_sockif;
/****************************************************************************
* Name: netlink_initialize()
*
* Description:
* Initialize the NetLink connection structures. Called once and only
* from the networking layer.
*
****************************************************************************/
void netlink_initialize(void);
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* Name: netlink_notifier_setup
*
* Description:
* Set up to perform a callback to the worker function the Netlink
* response data is received. 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 Netlink response data is available.
* conn - The Netlink connection where the response is expected.
* arg - A user-defined argument that will be available to the worker
* function when it runs.
*
* Returned Value:
* Zero (OK) is returned if the notification was successfully set up.
* A negated error value is returned if an unexpected error occurred
* and no notification will occur.
*
****************************************************************************/
int netlink_notifier_setup(worker_t worker, FAR struct netlink_conn_s *conn,
FAR void *arg);
/****************************************************************************
* Name: netlink_notifier_teardown
*
* Description:
* Eliminate a Netlink response notification previously setup by
* netlink_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:
* conn - Teardown the notification for this Netlink connection.
*
****************************************************************************/
void netlink_notifier_teardown(FAR struct netlink_conn_s *conn);
/****************************************************************************
* Name: netlink_notifier_signal
*
* Description:
* New Netlink response data is available. Execute worker thread
* functions for all threads that wait for response data.
*
* Input Parameters:
* conn - The Netlink connection where the response was just buffered.
*
* Returned Value:
* None.
*
****************************************************************************/
void netlink_notifier_signal(FAR struct netlink_conn_s *conn);
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* Name: netlink_route_sendto()
*
* Description:
* Perform the sendto() operation for the NETLINK_ROUTE protocol.
*
****************************************************************************/
#ifdef CONFIG_NETLINK_ROUTE
ssize_t netlink_route_sendto(NETLINK_HANDLE handle,
FAR const struct nlmsghdr *nlmsg,
size_t len, int flags,
FAR const struct sockaddr_nl *to,
socklen_t tolen);
/****************************************************************************
* Name: netlink_device_notify()
*
* Description:
* Perform the route broadcast for the NETLINK_ROUTE protocol.
*
****************************************************************************/
void netlink_device_notify(FAR struct net_driver_s *dev);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_NET_NETLINK */
#endif /* __NET_NETLINK_NETLINK_H */