private async Task <IP4Addr> Resolve(ParsedDomain domain)
{
if (domain.IsTopLevelDomain())
{
int rootServerIndex = Interlocked.Increment(ref rootServerCounter) % dnsClient.GetRootServers().Count;
IP4Addr rootServerIP = dnsClient.GetRootServers()[rootServerIndex];
return(dnsClient.Resolve(rootServerIP, domain.GetThisLevelSubdomain()).Result);
}
else
{
var upperLevelIP = await AssignResolverAndResolve(domain.GetUpperLevel());
return(dnsClient.Resolve(upperLevelIP, domain.GetThisLevelSubdomain()).Result);
}
}
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);
}
public Task <IP4Addr> ResolveRecursive(string domain)
{
return(Task <IP4Addr> .Run(() => {
string[] domains = domain.Split('.');
Array.Reverse(domains);
IP4Addr res = dnsClient.GetRootServers()[0];
foreach (var sub in domains)
{
var t = dnsClient.Resolve(res, sub);
t.Wait();
res = t.Result;
}
return res;
}));
}