private IP4Addr resolveSubDomain(string domain, IP4Addr start)
{
string[] domains = domain.Split('.');
Array.Reverse(domains);
IP4Addr res = start;
for (var i = 0; i < domains.Length; i++)
{
var sub = domains[i];
string cacheKey = "";
for (var j = i; j >= 0; j--)
{
cacheKey += domains[j] + (j == 0 ? "" : ".");
}
Task <IP4Addr> t;
mut.WaitOne();
if (IpCache.ContainsKey(cacheKey))
{
t = IpCache[cacheKey];
dbg("Cache hit " + cacheKey);
}
else
{
dbg("Setting cache for " + cacheKey);
t = dnsClient.Resolve(res, sub);
IpCache[cacheKey] = t;
}
mut.ReleaseMutex();
if (t.IsCompleted)
{
dbg("Cache needs verifying");
// task has already been finished, verify cache
Task <String> reverse = dnsClient.Reverse(t.Result);
reverse.Wait();
if (reverse.Result != cacheKey)
{
dbg("Cache verification failed. " + reverse.Result);
IpCache.Remove(cacheKey, out Task <IP4Addr> v);
// go level back
i = Math.Max(-1, i - 2);
continue;
}
}
t.Wait();
res = t.Result;
}
return(res);
}
private async Task <String> AsignReverserAndReverse(IP4Addr ip)
{
Task <string> reverser;
var hasReverser = reversers.TryGetValue(ip, out reverser);
if (hasReverser)
{
return(reverser.Result);
}
else
{
reverser = reversers.GetOrAdd(ip, dnsClient.Reverse(ip));
return(reverser.Result);
}
}