/// <summary>
/// Get cached list of authoritative name server ip addresses
/// </summary>
/// <param name="domainName"></param>
/// <param name="round"></param>
/// <returns></returns>
public async Task <DnsLookupResult> GetAuthority(string domainName, int round = 0, bool followCnames = true, DnsLookupResult?from = null)
{
var key = domainName.ToLower().TrimEnd('.');
try
{
// Example: _acme-challenge.sub.example.co.uk
domainName = domainName.TrimEnd('.');
// First domain we should try to ask is the tld (e.g. co.uk)
var rootDomain = _domainParser.GetTLD(domainName);
var testZone = rootDomain;
var client = GetDefaultClient(round);
// Other sub domains we should ask:
// 1. example
// 1. sub
// 2. _acme-challenge
var remainingParts = domainName.Substring(0, domainName.LastIndexOf(rootDomain))
.Trim('.').Split('.').Where(x => !string.IsNullOrEmpty(x))
.Reverse().ToArray();
var digDeeper = true;
IEnumerable <IPAddress>?ipSet = null;
do
{
// Partial result cachign
if (!_authoritativeNs.ContainsKey(testZone))
{
_log.Verbose("Querying server {server} about {part}", client.IpAddress, testZone);
using (LogContext.PushProperty("Domain", testZone))
{
var tempResult = await client.GetNameServers(testZone, round);
_authoritativeNs.TryAdd(testZone, tempResult?.ToList() ?? ipSet ?? _defaultNs);
}
}
ipSet = _authoritativeNs[testZone];
client = Produce(ipSet.OrderBy(x => Guid.NewGuid()).First());
// CNAME only valid for full domain. Subdomains may be
// regular records again
if (followCnames && testZone == key)
{
var cname = default(string?);
if (!_cnames.ContainsKey(key))
{
_cnames.TryAdd(key, await client.GetCname(testZone));
}
cname = _cnames[key];
if (cname != null)
{
return(await GetAuthority(cname, round, true, Produce(key, from)));
}
}
if (remainingParts.Any())
{
testZone = $"{remainingParts[0]}.{testZone}";
remainingParts = remainingParts[1..];
private string?GetTldCache(string domain)
{
if (_tldCache.TryGetValue(domain, out var value))
{
return(value);
}
value = _domainParser.GetTLD(domain);
_tldCache.Add(domain, value);
return(value);
}
private string?GetTldCache(string domain)
{
if (_tldCache.TryGetValue(domain, out var value))
{
return(value);
}
try
{
value = _domainParser.GetTLD(domain);
_tldCache.Add(domain, value);
}
catch
{
value = ".error";
_tldCache.Add(domain, value);
}
return(value);
}
public string GetRootDomain(string domainName) => _domainParser.GetTLD(domainName.TrimEnd('.'));
/// <summary>
/// Get cached list of authoritative name server ip addresses
/// </summary>
/// <param name="domainName"></param>
/// <param name="round"></param>
/// <returns></returns>
public async Task <DnsLookupResult> GetAuthority(string domainName, int round = 0, bool followCnames = true)
{
var key = domainName.ToLower().TrimEnd('.');
if (!_authoritativeNs.ContainsKey(key))
{
try
{
// Example: _acme-challenge.sub.example.co.uk
domainName = domainName.TrimEnd('.');
// First domain we should try to ask is the tld (e.g. co.uk)
var rootDomain = _domainParser.GetTLD(domainName);
var testZone = rootDomain;
var client = GetDefaultClient(round);
// Other sub domains we should ask:
// 1. example
// 1. sub
// 2. _acme-challenge
var remainingParts = domainName.Substring(0, domainName.LastIndexOf(rootDomain))
.Trim('.').Split('.')
.Where(x => !string.IsNullOrEmpty(x));
remainingParts = remainingParts.Reverse();
var digDeeper = true;
IEnumerable <IPAddress>?ipSet = null;
do
{
// Partial result cachign
if (!_authoritativeNs.ContainsKey(testZone))
{
_log.Verbose("Querying server {server} about {part}", client.IpAddress, testZone);
using (LogContext.PushProperty("Domain", testZone))
{
var tempResult = await client.GetNameServers(testZone, round);
_authoritativeNs.Add(testZone, tempResult?.ToList() ?? ipSet ?? _defaultNs);
}
}
ipSet = _authoritativeNs[testZone];
client = Produce(ipSet.OrderBy(x => Guid.NewGuid()).First());
// CNAME only valid for full domain. Subdomains may be
// regular records again
if (followCnames && testZone == key)
{
var cname = await client.GetCname(testZone);
if (cname != null)
{
return(await GetAuthority(cname, round));
}
}
if (remainingParts.Any())
{
testZone = $"{remainingParts.First()}.{testZone}";
remainingParts = remainingParts.Skip(1).ToArray();
}
else
{
digDeeper = false;
}
}while (digDeeper);
if (ipSet == null)
{
throw new Exception("No results");
}
}
catch (Exception ex)
{
_log.Warning("Unable to find or contact authoritative name servers for {domainName}: {message}", domainName, ex.Message);
_authoritativeNs.Add(key, _defaultNs);
}
}
return(new DnsLookupResult(key, _authoritativeNs[key].Select(ip => Produce(ip))));
}
/// <summary>
/// Get cached list of authoritative name server ip addresses
/// </summary>
/// <param name="domainName"></param>
/// <param name="round"></param>
/// <returns></returns>
private async Task <IEnumerable <IPAddress> > GetAuthoritativeNameServersForDomain(string domainName, int round)
{
var key = domainName.ToLower().TrimEnd('.');
if (!_authoritativeNs.ContainsKey(key))
{
try
{
// _acme-challenge.sub.example.co.uk
domainName = domainName.TrimEnd('.');
// First domain we should try to ask
var rootDomain = _domainParser.GetTLD(domainName);
var testZone = rootDomain;
var client = GetDefaultClient(round);
// Other sub domains we should try asking:
// 1. sub
// 2. _acme-challenge
var remainingParts = domainName.Substring(0, domainName.LastIndexOf(rootDomain))
.Trim('.').Split('.')
.Where(x => !string.IsNullOrEmpty(x));
remainingParts = remainingParts.Reverse();
var digDeeper = true;
IEnumerable <IPAddress>?ipSet = null;
do
{
// Partial result cachign
if (!_authoritativeNs.ContainsKey(testZone))
{
_log.Verbose("Querying server {server} about {part}", client.IpAddress, testZone);
using (LogContext.PushProperty("Domain", testZone))
{
var tempResult = await client.GetAuthoritativeNameServers(testZone, round);
_authoritativeNs.Add(testZone, tempResult?.ToList() ?? ipSet ?? _defaultNs);
}
}
ipSet = _authoritativeNs[testZone];
client = Produce(ipSet.OrderBy(x => Guid.NewGuid()).First());
if (remainingParts.Any())
{
testZone = $"{remainingParts.First()}.{testZone}";
remainingParts = remainingParts.Skip(1).ToArray();
}
else
{
digDeeper = false;
}
}while (digDeeper);
if (ipSet == null)
{
throw new Exception("No results");
}
}
catch (Exception ex)
{
_log.Warning("Unable to find or contact authoritative name servers for {domainName}: {message}", domainName, ex.Message);
_authoritativeNs.Add(key, _defaultNs);
}
}
return(_authoritativeNs[key]);
}
