public async Task CanConnectToAtLeastTwoNtpServers()
{
var standardTimerServer = AbstractLicenseValidator.StandardTimeServer;
int failingHosts = 0;
foreach (var host in standardTimerServer)
{
var hostTiming = Stopwatch.StartNew();
var addresses = await Dns.GetHostAddressesAsync(host).ConfigureAwait(false);
var endPoint = new IPEndPoint(addresses[0], 123);
using (var udpClient = new UdpClient())
{
udpClient.Connect(endPoint);
var sntpData = new byte[SntpClient.SntpDataLength];
sntpData[0] = 0x1B; // version = 4 & mode = 3 (client)
var sendTask = udpClient.SendAsync(sntpData, sntpData.Length);
if (await Task.WhenAny(sendTask, Task.Delay(TimeSpan.FromMilliseconds(500))).ConfigureAwait(false) != sendTask)
{
failingHosts++;
continue;
}
var receiveTask = udpClient.ReceiveAsync();
if (await Task.WhenAny(receiveTask, Task.Delay(TimeSpan.FromMilliseconds(500))).ConfigureAwait(false) != receiveTask)
{
failingHosts++;
continue;
}
var result = receiveTask.Result;
hostTiming.Stop();
if (SntpClient.IsResponseValid(result.Buffer) == false)
{
failingHosts++;
continue;
}
var transmitTimestamp = SntpClient.GetTransmitTimestamp(result.Buffer);
//The idea is not to validate our own clock but to make sure we didn't get garbage.
Assert.True((DateTime.UtcNow - transmitTimestamp).Duration() < TimeSpan.FromHours(1));
}
}
Assert.True(standardTimerServer.Length - failingHosts > 2, $"Connection failed in {failingHosts} or more hosts");
}
public async Task CanConnectToAllNtpServers()
{
foreach (var host in AbstractLicenseValidator.StandardTimeServer)
{
var hostTiming = Stopwatch.StartNew();
var exceptionWasThrown = false;
var addresses = await Dns.GetHostAddressesAsync(host).ConfigureAwait(false);
var endPoint = new IPEndPoint(addresses[0], 123);
using (var udpClient = new UdpClient())
{
udpClient.Connect(endPoint);
var sntpData = new byte[SntpClient.SntpDataLength];
sntpData[0] = 0x1B; // version = 4 & mode = 3 (client)
var sendTask = udpClient.SendAsync(sntpData, sntpData.Length);
if (await Task.WhenAny(sendTask, Task.Delay(TimeSpan.FromMilliseconds(500))).ConfigureAwait(false) != sendTask)
{
throw new TimeoutException("Failed to send data to " + host + "within 500ms");
}
var receiveTask = udpClient.ReceiveAsync();
if (await Task.WhenAny(receiveTask, Task.Delay(TimeSpan.FromMilliseconds(500))).ConfigureAwait(false) != receiveTask)
{
throw new TimeoutException("Failed to receive data to " + host + " within 500ms");
}
var result = receiveTask.Result;
hostTiming.Stop();
if (SntpClient.IsResponseValid(result.Buffer) == false)
{
throw new BadRequestException("Did not get valid time information from " + host + " took " + hostTiming.Elapsed);
}
var transmitTimestamp = SntpClient.GetTransmitTimestamp(result.Buffer);
//The idea is not to validate our own clock but to make sure we didn't get garbage.
Assert.True((DateTime.UtcNow - transmitTimestamp).Duration() < TimeSpan.FromHours(1));
}
}
}
