apps/net: add if network conntivity check API

[zs39]

Summary

Perform connectivity testing on the specified network interface card.

Impact

Adding new APIs will not affect existing functionality.

Testing

Use the following code to test.

/****************************************************************************
 * apps/examples/hello/hello_main.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>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

#ifdef CONFIG_NETUTILS_PING
#include <netutils/netlib.h>
#endif

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * hello_main
 ****************************************************************************/

int main(int argc, FAR char *argv[])
{
  printf("Hello, World!!\n");

#ifdef CONFIG_NETUTILS_PING
  const char *ifname = "eth0";  /* Default network interface */
  int timeout = 5000;            /* 5 seconds (in milliseconds) */
  int retry = 3;                 /* 3 times */
  int replies;

  /* Optional: interface name, timeout and retry from command line */
  if (argc > 1)
    {
      ifname = argv[1];
    }

  if (argc > 2)
    {
      timeout = atoi(argv[2]);
    }

  if (argc > 3)
    {
      retry = atoi(argv[3]);
    }

  printf("\n=== Network Interface Connectivity Test ===\n");
  printf("Interface: %s\n", ifname);
  printf("Timeout: %d ms\n", timeout);
  printf("Retry: %d times\n", retry);
  printf("Checking connectivity by pinging gateway of %s...\n\n", ifname);

  replies = netlib_check_ifconnectivity(ifname, timeout, retry);

  if (replies > 0)
    {
      printf("SUCCESS: Interface %s is reachable!\n", ifname);
      printf("Received %d ping reply(ies) from gateway.\n", replies);
      return 0;
    }
  else if (replies == 0)
    {
      printf("FAILED: Interface %s is not reachable.\n", ifname);
      printf("No ping replies received from gateway.\n");
      return 1;
    }
  else
    {
      printf("ERROR: Failed to check connectivity for %s.\n", ifname);
      printf("Error code: %d (errno: %d)\n", replies, errno);
      return 1;
    }
#else
  printf("\nNote: Network connectivity check is disabled.\n");
  printf("Enable CONFIG_NETUTILS_PING to use this feature.\n");
  return 0;
#endif
}

The execution results are as follows，Test results show that the API works correctly.

nsh> hello
Hello, World!!

=== Network Interface Connectivity Test ===
Interface: eth0
Timeout: 5000 ms
Retry: 3 times
Checking connectivity by pinging gateway of eth0...

SUCCESS: Interface eth0 is reachable!
Received 3 ping reply(ies) from gateway.

[zs39]

Documentation supplement here
apache/nuttx#17786

[cederom]

Thank you @zs39 :-)