iOS Objective-C 以编程方式获取 VPN IP

我使用第三方应用程序连接VPN，我们可以在以下位置获取详细信息Settings->VPN->information。我怎样才能得到Assigned IP通过 Objective-C 在我们的应用程序中以编程方式？

NSString *address = @"error";
struct ifaddrs *interfaces = NULL;
struct ifaddrs *temp_addr = NULL;
int success = 0;

// retrieve the current interfaces - returns 0 on success
success = getifaddrs(&interfaces);
if (success == 0) {
    // Loop through linked list of interfaces
    temp_addr = interfaces;
    while (temp_addr != NULL) {
        if( temp_addr->ifa_addr->sa_family == AF_INET) {
            // Check if interface is en0 which is the wifi connection on the iPhone
            if ([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"utun1"])
            {
                // Get NSString from C String
                address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
                NSLog(@"ifaName: %@, Address: %@",[NSString stringWithUTF8String:temp_addr->ifa_name],address);
            }
        }

        temp_addr = temp_addr->ifa_next;
    }
}

// Free memory
freeifaddrs(interfaces);

address将有分配的IP地址