/// <summary>
/// Check's if the request IP has a valid PTR record.
/// </summary>
/// <param name="ip"></param>
/// <returns></returns>
private async Task PtrLookupIp(IPAddress ip)
{
try
{
_requestHostname = await Dns.GetHostEntryAsync(ip);
}
catch (SocketException ex)
{
_logger.LogEvent(LogLevel.Error, $"PTR Lookup Error: {ex.Message}");
}
}
/// <summary>
/// Checks requests IP and/or Hostname against the Rbl's database
/// </summary>
/// <param name="context"></param>
/// <param name="logger"></param>
/// <returns></returns>
public async Task <bool> CheckProvider(HttpContext context, TrotterLog logger)
{
_logger = logger;
_context = context;
var requestIp = context.Connection.RemoteIpAddress;
var formattedIp = FormatIp(requestIp);
if (ProviderType == RblType.Both || ProviderType == RblType.Hostname)
{
_logger.LogEvent(LogLevel.Information, "Initiating PTR Lookup & Hostname check...");
await PtrLookupIp(requestIp);
await RblHostLookup(_requestHostname.HostName);
_logger.LogEvent(LogLevel.Information, "PTR Lookup & Hostname check completed!");
}
_logger.LogEvent(LogLevel.Information, "Initiating IP Lookup against RBL");
await RblHostLookup(formattedIp);
_logger.LogEvent(LogLevel.Information, $"RBL Lookup has completed for {ProviderName}");
return(_isListed);
}
public async Task Invoke(HttpContext context)
{
//If IPAddress is private then ignore.
if (IsInternal(context.Connection.RemoteIpAddress))
{
_logger.LogEvent(LogLevel.Information, $"Not checking the remote IP {context.Connection.RemoteIpAddress} as it's private.");
await _next.Invoke(context);
return;
}
_logger.LogEvent(LogLevel.Information, $"The remote IP {context.Connection.RemoteIpAddress} is public.");
var isListed = false;
//Process the RBL Providers
foreach (var provider in _rblProviders)
{
var providerResult = await InitiateProvider(context, provider);
if (!providerResult)
{
continue;
}
isListed = true;
if (!_continueChecks)
{
break;
}
}
if (!isListed)
{
_logger.LogEvent(LogLevel.Information, $"Remote IP/PTR is NOT listed on any of the Rbl Providers");
_logger.LogEvent(LogLevel.Information, $"Moving onto the next Middleware Component");
await _next.Invoke(context);
}
//Not Listed == Short-circuits request pipeline (no booley, no invokey)
}