public static void Init(AuthTolkenTimeout authTolkenTimeout)
{
Debug.Assert(null == AuthString);
AcceptedAuthTolkenTimeouts = authTolkenTimeout;
AuthString = GetRandomString();
s_connectionCounter = new List<int>(0);
}
public static bool IsValid(AuthTolkenTimeout timeout,
string authTolken,
int adjustedAmount,
int clientId,
bool adjustForTransmission)
{
bool valid = false;
// This has to be single threaded to avoid race conditions for authenticating the client packet count
lock (typeof (TolkenAuthenticator))
{
if (AcceptedAuthTolkenTimeouts == AuthTolkenTimeout.NoAuth)
{
valid = true;
}
else if (0 < clientId &&
clientId <= s_connectionCounter.Count &&
AuthTolkenTimeout.Any != timeout &&
(AcceptedAuthTolkenTimeouts == AuthTolkenTimeout.Any || AcceptedAuthTolkenTimeouts == timeout))
{
DateTime now = DateTime.UtcNow;
int numAdjustSeconds = 0;
// We have to round our seconds to the every nth second based on timeout
switch (timeout)
{
case AuthTolkenTimeout.FiveSeconds:
numAdjustSeconds = 5 + (5 - (now.Second%5));
numAdjustSeconds -= adjustForTransmission && numAdjustSeconds > adjustedAmount ? 5 : 0;
break;
case AuthTolkenTimeout.TenSecionds:
numAdjustSeconds = 10 + (10 - (now.Second%10));
numAdjustSeconds -= adjustForTransmission && numAdjustSeconds > adjustedAmount ? 10 : 0;
break;
case AuthTolkenTimeout.ThirtySeconds:
numAdjustSeconds = 30 + (30 - (now.Second%30));
numAdjustSeconds -= adjustForTransmission && numAdjustSeconds > adjustedAmount ? 30 : 0;
break;
case AuthTolkenTimeout.SixtySeconds:
numAdjustSeconds = 60 + (60 - (now.Second%60));
numAdjustSeconds -= adjustForTransmission && numAdjustSeconds > adjustedAmount ? 60 : 0;
break;
default:
Debug.Assert(false, "Unexpected timeout");
break;
}
DateTime adjustedTime = now.AddSeconds(numAdjustSeconds);
// we only want granularity down to seconds
var adjustedTimeToSecond = new DateTime(adjustedTime.Year,
adjustedTime.Month,
adjustedTime.Day,
adjustedTime.Hour,
adjustedTime.Minute,
adjustedTime.Second);
int currentClientCounter = s_connectionCounter[clientId - 1];
string computedAuthTolken =
Sha1HashOfString(adjustedTimeToSecond.ToString("yyyy-MM-dd:HH:mm:ss") + AuthString +
currentClientCounter);
valid = authTolken == computedAuthTolken;
if (!valid && !adjustForTransmission)
{
// lets try one last time adjusting
valid = IsValid(timeout, authTolken, adjustedAmount, clientId, true /*adjustForTransmission*/);
}
else if (valid)
{
IncrementClient(clientId);
}
}
}
return valid;
}
public static bool IsValid(AuthTolkenTimeout timeout, string authTolken, int adjustedAmount, int clientId)
{
return IsValid(timeout, authTolken, adjustedAmount, clientId, false /*adjustForTransmission*/);
}
