How to find the status of VPN connection through framework APIs or any other efficient method?

问题

So far:

I found the following solutions

Using Broadcastreceiver

The broadcast receiver is deprecated from ICS
Using Ping or Traceroute

It's definitely going to take lots of time and its not efficient
Polling for DNS server changes

It's definitely going to take lots of time and its not efficient
Using ip-address

Even though it won't take much time depending on the network connection it may vary

My conclusion:

So far all the solutions I found are either not efficient or not so reliable.

My questions:

If VPN is connected in android device then android OS must be aware of it.

Are there any public android framework APIs to read it because finding it locally is most efficient and reliable solution ?

Are there any other efficient and reliable ways to achieve it (like integrating a C or C plus plus library with NDK)?

Note:

I couldn't find any custom broadcast senders/AIDL from OpenVPN for Android as well

回答1:

You can try to check for tun0 INTERFACE, It is being start afther the establish command.

try {
    for( NetworkInterface intf : Collections.list(NetworkInterface.getNetworkInterfaces())) {

        // Pass over dormant interfaces
        if(!intf.isUp() || intf.getInterfaceAddresses().size() == 0)
            continue;

            if ("tun0".equals(intf.getName())){
                // The VPN is up
                break;
            }
    }
}

this also might work:

(Collections.list(NetworkInterface.getByName("tun0")

回答2:

Have you used - VpnService

As per documentation -

Prepare to establish a VPN connection. This method returns 'null' if the VPN application 
is 'already prepared'.

From here-

http://developer.android.com/reference/android/net/VpnService.html#prepare(android.content.Context)

 Intent intent = VpnService.prepare(getApplicationContext());
  if (intent == null) {
    // this means there is already a prepared VPN connection
  }