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DnsResolver.pas
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// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
unit
DnsResolver;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
interface
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
uses
Classes,
SyncObjs,
CommunicationChannels,
Configuration,
IPUtils;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TDnsResolver = class
public
class procedure StartResolver;
class procedure StopResolver;
private
class procedure StartResolverThreads;
class procedure StopResolverThreads;
public
class procedure HandleDnsRequestForIPv4Udp(ServerCommunicationChannel: TIPv4UdpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv4Address; Port: Word);
class procedure HandleDnsRequestForIPv4Tcp(ServerCommunicationChannel: TIPv4TcpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv4Address; Port: Word);
class procedure HandleDnsRequestForIPv6Udp(ServerCommunicationChannel: TIPv6UdpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv6Address; Port: Word);
class procedure HandleDnsRequestForIPv6Tcp(ServerCommunicationChannel: TIPv6TcpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv6Address; Port: Word);
public
class procedure HandleDnsResponseForIPv4Udp(ServerCommunicationChannel: TIPv4UdpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; DnsServerIndex: Integer; DnsServerResponseTime: Double; DnsServerConfiguration: TDnsServerConfiguration);
class procedure HandleDnsResponseForIPv4Tcp(ServerCommunicationChannel: TIPv4TcpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; DnsServerIndex: Integer; DnsServerResponseTime: Double; DnsServerConfiguration: TDnsServerConfiguration);
class procedure HandleDnsResponseForIPv6Udp(ServerCommunicationChannel: TIPv6UdpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; DnsServerIndex: Integer; DnsServerResponseTime: Double; DnsServerConfiguration: TDnsServerConfiguration);
class procedure HandleDnsResponseForIPv6Tcp(ServerCommunicationChannel: TIPv6TcpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; DnsServerIndex: Integer; DnsServerResponseTime: Double; DnsServerConfiguration: TDnsServerConfiguration);
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv4UdpDnsResolver = class(TThread)
public
constructor Create;
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv4TcpDnsResolver = class(TThread)
public
constructor Create;
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv4TcpDnsResolverSession = class(TThread)
private
ServerCommunicationChannel: TIPv4TcpCommunicationChannel;
public
constructor Create(ServerCommunicationChannel: TIPv4TcpCommunicationChannel);
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv6UdpDnsResolver = class(TThread)
public
constructor Create;
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv6TcpDnsResolver = class(TThread)
public
constructor Create;
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TIPv6TcpDnsResolverSession = class(TThread)
private
ServerCommunicationChannel: TIPv6TcpCommunicationChannel;
public
constructor Create(ServerCommunicationChannel: TIPv6TcpCommunicationChannel);
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
type
TDnsResolverAddressCachePruner = class(TThread)
public
constructor Create;
procedure Execute; override;
destructor Destroy; override;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
implementation
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
uses
SysUtils,
Windows,
AddressCache,
DnsForwarder,
DnsOverHttpsCache,
DnsProtocol,
Environment,
HitLogger,
HostsCache,
MD5,
MemoryManager,
SessionCache,
Tracer;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
const
DNS_RESOLVER_WAIT_TIME = 499;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
var
TDnsResolver_Lock: TCriticalSection;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
var
IPv4UdpDnsResolver: TIPv4UdpDnsResolver;
IPv4TcpDnsResolver: TIPv4TcpDnsResolver;
IPv6UdpDnsResolver: TIPv6UdpDnsResolver;
IPv6TcpDnsResolver: TIPv6TcpDnsResolver;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
var
DnsResolverAddressCachePruner: TDnsResolverAddressCachePruner;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.StartResolver;
begin
Randomize;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Initializing...');
TCommunicationChannel.Initialize; TDnsOverHttpsCache.Initialize; TSessionCache.Initialize; TAddressCache.Initialize; THostsCache.Initialize;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done initializing.');
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Reading system info...');
TEnvironment.ReadSystemInfo;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done reading system info.');
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Loading configuration...');
TConfiguration.LoadFromFile(TConfiguration.GetConfigurationFileName);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done loading configuration.');
if FileExists(TConfiguration.GetHostsCacheFileName) then begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Loading hosts cache items...');
try
THostsCache.LoadFromFile(TConfiguration.GetHostsCacheFileName);
except
on E: Exception do if TTracer.IsEnabled then TTracer.Trace(TracePriorityError, 'TDnsResolver.StartResolver: The following error occurred while loading hosts cache items: ' + E.Message);
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done loading hosts cache items.');
end;
if not(TConfiguration.GetAddressCacheDisabled) and not(TConfiguration.GetAddressCacheInMemoryOnly) and FileExists(TConfiguration.GetAddressCacheFileName) then begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Loading address cache items...');
try
TAddressCache.LoadFromFile(TConfiguration.GetAddressCacheFileName);
except
on E: Exception do if TTracer.IsEnabled then TTracer.Trace(TracePriorityError, 'TDnsResolver.StartResolver: The following error occurred while loading address cache items: ' + E.Message);
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done loading address cache items.');
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Starting resolver threads...');
TDnsResolver.StartResolverThreads;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StartResolver: Done starting resolver threads.');
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.StartResolverThreads;
begin
TDnsResolver_Lock := TCriticalSection.Create;
if TConfiguration.IsLocalIPv4BindingEnabled then begin
IPv4UdpDnsResolver := TIPv4UdpDnsResolver.Create; IPv4TcpDnsResolver := TIPv4TcpDnsResolver.Create;
end;
if TConfiguration.IsLocalIPv6BindingEnabled then begin
IPv6UdpDnsResolver := TIPv6UdpDnsResolver.Create; IPv6TcpDnsResolver := TIPv6TcpDnsResolver.Create;
end;
if not TConfiguration.GetAddressCacheDisabled then begin
DnsResolverAddressCachePruner := TDnsResolverAddressCachePruner.Create;
end;
if TConfiguration.IsLocalIPv4BindingEnabled then begin
IPv4UdpDnsResolver.Resume; IPv4TcpDnsResolver.Resume;
end;
if TConfiguration.IsLocalIPv6BindingEnabled then begin
IPv6UdpDnsResolver.Resume; IPv6TcpDnsResolver.Resume;
end;
if not TConfiguration.GetAddressCacheDisabled then begin
DnsResolverAddressCachePruner.Resume;
end;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.StopResolverThreads;
begin
if not(TConfiguration.GetAddressCacheDisabled) then begin
DnsResolverAddressCachePruner.Terminate;
end;
if TConfiguration.IsLocalIPv6BindingEnabled then begin
IPv6UdpDnsResolver.Terminate; IPv6TcpDnsResolver.Terminate; TerminateThread(IPv6TcpDnsResolver.Handle, 0);
end;
if TConfiguration.IsLocalIPv4BindingEnabled then begin
IPv4UdpDnsResolver.Terminate; IPv4TcpDnsResolver.Terminate; TerminateThread(IPv4TcpDnsResolver.Handle, 0);
end;
if TConfiguration.IsLocalIPv6BindingEnabled then begin
IPv6UdpDnsResolver.WaitFor;
end;
if TConfiguration.IsLocalIPv4BindingEnabled then begin
IPv4UdpDnsResolver.WaitFor;
end;
if TConfiguration.IsLocalIPv6BindingEnabled then begin
IPv6UdpDnsResolver.Free; IPv6TcpDnsResolver.Free;
end;
if TConfiguration.IsLocalIPv4BindingEnabled then begin
IPv4UdpDnsResolver.Free; IPv4TcpDnsResolver.Free;
end;
if not(TConfiguration.GetAddressCacheDisabled) then begin
DnsResolverAddressCachePruner.WaitFor;
end;
if not(TConfiguration.GetAddressCacheDisabled) then begin
DnsResolverAddressCachePruner.Free;
end;
TDnsResolver_Lock.Free; TDnsResolver_Lock := nil;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.StopResolver;
begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Stopping resolver threads...');
TDnsResolver.StopResolverThreads;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Done stopping resolver threads.');
if THitLogger.IsEnabled then begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Flushing hit log items...');
try
THitLogger.WriteAllPendingHitsToDisk(False);
except
on E: Exception do if TTracer.IsEnabled then TTracer.Trace(TracePriorityError, 'TDnsResolver.StopResolver: The following error occurred while flushing hit log items: ' + E.Message);
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Done flushing hit log items.');
end;
if not(TConfiguration.GetAddressCacheDisabled) and not(TConfiguration.GetAddressCacheInMemoryOnly) then begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Saving address cache items...');
try
TAddressCache.SaveToFile(TConfiguration.GetAddressCacheFileName);
except
on E: Exception do if TTracer.IsEnabled then TTracer.Trace(TracePriorityError, 'TDnsResolver.StopResolver: The following error occurred while saving address cache items: ' + E.Message);
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Done saving address cache items.');
end;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Finalizing...');
THostsCache.Finalize; TAddressCache.Finalize; TSessionCache.Finalize; TDnsOverHttpsCache.Finalize; TCommunicationChannel.Finalize;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.StopResolver: Done finalizing.');
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.HandleDnsRequestForIPv4Udp(ServerCommunicationChannel: TIPv4UdpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv4Address; Port: Word);
var
OriginalSessionId: Word; RequestHash: TMD5Digest; QueryType: Word; DomainName: String; IPv4Address: TIPv4Address; IPv6Address: TIPv6Address; RemappedSessionId: Word; DnsServerIndex: Integer; DnsServerConfiguration: TDnsServerConfiguration; Forwarded: Boolean;
begin
if (TDnsResolver_Lock <> nil) then begin
TDnsResolver_Lock.Acquire;
try
if (BufferLen >= MIN_DNS_PACKET_LEN) and (BufferLen <= MAX_DNS_PACKET_LEN) and TDnsProtocolUtility.IsValidRequestPacket(Buffer, BufferLen) then begin
OriginalSessionId := TDnsProtocolUtility.GetIdFromPacket(Buffer);
TDnsProtocolUtility.GetDomainNameAndQueryTypeFromRequestPacket(Buffer, BufferLen, DomainName, QueryType);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + ' received from client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' [' + TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, True) + '].');
if (QueryType = DNS_QUERY_TYPE_A) then begin
if TDnsOverHttpsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveIPv4ResponsePacket(DomainName, QueryType, IPv4Address, TConfiguration.GetGeneratedDnsResponseTimeToLive, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if TDnsOverHttpsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindFWItem(DomainName) then begin
// Don't do anything, let the execution flow...
end else if THostsCache.FindNXItem(DomainName) then begin
TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveIPv4ResponsePacket(DomainName, QueryType, IPv4Address, TConfiguration.GetGeneratedDnsResponseTimeToLive, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end;
end else if (QueryType = DNS_QUERY_TYPE_AAAA) then begin
if TDnsOverHttpsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveIPv6ResponsePacket(DomainName, QueryType, IPv6Address, TConfiguration.GetGeneratedDnsResponseTimeToLive, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if TDnsOverHttpsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if TConfiguration.GetSinkholeIPv6Lookups then begin
TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindFWItem(DomainName) then begin
// Don't do anything, let the execution flow...
end else if THostsCache.FindNXItem(DomainName) then begin
TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveIPv6ResponsePacket(DomainName, QueryType, IPv6Address, TConfiguration.GetGeneratedDnsResponseTimeToLive, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end;
end else if (QueryType = DNS_QUERY_TYPE_HTTPS) then begin
if TDnsOverHttpsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveHttpsResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if TDnsOverHttpsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveHttpsResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindFWItem(DomainName) then begin
// Don't do anything, let the execution flow...
end else if THostsCache.FindNXItem(DomainName) then begin
TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveHttpsResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end else if THostsCache.FindIPv6Item(DomainName, IPv6Address) then begin
TDnsProtocolUtility.BuildPositiveHttpsResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using hosts cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('H', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'H', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end;
end else if (QueryType = DNS_QUERY_TYPE_PTR) then begin
if not(TConfiguration.GetForwardPrivateReverseLookups) and TDnsProtocolUtility.IsPrivateReverseLookup(DomainName) then begin
TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end;
end else if (QueryType = DNS_QUERY_TYPE_ANY) then begin
if not(TConfiguration.GetForwardPrivateReverseLookups) and TDnsProtocolUtility.IsPrivateReverseLookup(DomainName) then begin
TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
Exit;
end;
end;
TDnsProtocolUtility.SetIdIntoPacket(0, Buffer); RequestHash := TMD5.Compute(Buffer, BufferLen); TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Buffer);
if not(TConfiguration.IsDomainNameAffinityMatch(DomainName, TConfiguration.GetAddressCacheDomainNameAffinityMask)) or not(TConfiguration.IsQueryTypeAffinityMatch(QueryType, TConfiguration.GetAddressCacheQueryTypeAffinityMask)) then begin
TSessionCache.ReserveItem(ArrivalTime, OriginalSessionId, RemappedSessionId);
TDnsProtocolUtility.SetIdIntoPacket(RemappedSessionId, Buffer);
Forwarded := False;
for DnsServerIndex := 0 to (Configuration.MAX_NUM_DNS_SERVERS - 1) do begin
DnsServerConfiguration := TConfiguration.GetDnsServerConfiguration(DnsServerIndex);
if DnsServerConfiguration.IsEnabled then begin
if TConfiguration.IsDomainNameAffinityMatch(DomainName, DnsServerConfiguration.DomainNameAffinityMask) and TConfiguration.IsQueryTypeAffinityMatch(QueryType, DnsServerConfiguration.QueryTypeAffinityMask) then begin
if TDnsForwarder.ForwardDnsRequestForIPv4Udp(ServerCommunicationChannel, ArrivalTime, DnsServerIndex, DnsServerConfiguration, Buffer, BufferLen, RemappedSessionId) then begin
Forwarded := True;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' forwarded to server ' + IntToStr(DnsServerIndex + 1) + ' (cache exception).');
end else begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' failed to be forwarded to server ' + IntToStr(DnsServerIndex + 1) + ' (cache exception).');
end;
end;
end;
end;
if Forwarded then begin
TSessionCache.InsertIPv4Item(ArrivalTime, OriginalSessionId, RemappedSessionId, RequestHash, Address, Port, False, True);
if THitLogger.IsEnabled and (Pos('F', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'F', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end else begin
if (QueryType = DNS_QUERY_TYPE_PTR) then TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen) else TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end;
end else begin
if not(TConfiguration.GetAddressCacheDisabled) then begin
case TAddressCache.FindItem(ArrivalTime, RequestHash, Output, OutputLen) of
RecentEnough:
begin
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using address cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('C', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'C', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end;
NeedsUpdate:
begin
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using address cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('C', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'C', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
TSessionCache.ReserveItem(ArrivalTime, OriginalSessionId, RemappedSessionId);
TDnsProtocolUtility.SetIdIntoPacket(RemappedSessionId, Buffer);
Forwarded := False;
for DnsServerIndex := 0 to (Configuration.MAX_NUM_DNS_SERVERS - 1) do begin
DnsServerConfiguration := TConfiguration.GetDnsServerConfiguration(DnsServerIndex);
if DnsServerConfiguration.IsEnabled then begin
if TConfiguration.IsDomainNameAffinityMatch(DomainName, DnsServerConfiguration.DomainNameAffinityMask) and TConfiguration.IsQueryTypeAffinityMatch(QueryType, DnsServerConfiguration.QueryTypeAffinityMask) then begin
if TDnsForwarder.ForwardDnsRequestForIPv4Udp(ServerCommunicationChannel, ArrivalTime, DnsServerIndex, DnsServerConfiguration, Buffer, BufferLen, RemappedSessionId) then begin
Forwarded := True;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' forwarded to server ' + IntToStr(DnsServerIndex + 1) + ' (silent update).');
end else begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' failed to be forwarded to server ' + IntToStr(DnsServerIndex + 1) + ' (silent update).');
end;
end;
end;
end;
if Forwarded then begin
TSessionCache.InsertIPv4Item(ArrivalTime, OriginalSessionId, RemappedSessionId, RequestHash, Address, Port, True, False);
end;
end;
NotFound:
begin
TSessionCache.ReserveItem(ArrivalTime, OriginalSessionId, RemappedSessionId);
TDnsProtocolUtility.SetIdIntoPacket(RemappedSessionId, Buffer);
Forwarded := False;
for DnsServerIndex := 0 to (Configuration.MAX_NUM_DNS_SERVERS - 1) do begin
DnsServerConfiguration := TConfiguration.GetDnsServerConfiguration(DnsServerIndex);
if DnsServerConfiguration.IsEnabled then begin
if TConfiguration.IsDomainNameAffinityMatch(DomainName, DnsServerConfiguration.DomainNameAffinityMask) and TConfiguration.IsQueryTypeAffinityMatch(QueryType, DnsServerConfiguration.QueryTypeAffinityMask) then begin
if TDnsForwarder.ForwardDnsRequestForIPv4Udp(ServerCommunicationChannel, ArrivalTime, DnsServerIndex, DnsServerConfiguration, Buffer, BufferLen, RemappedSessionId) then begin
Forwarded := True;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' forwarded to server ' + IntToStr(DnsServerIndex + 1) + '.');
end else begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' failed to be forwarded to server ' + IntToStr(DnsServerIndex + 1) + '.');
end;
end;
end;
end;
if Forwarded then begin
TSessionCache.InsertIPv4Item(ArrivalTime, OriginalSessionId, RemappedSessionId, RequestHash, Address, Port, False, False);
if THitLogger.IsEnabled and (Pos('F', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'F', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end else begin
if (QueryType = DNS_QUERY_TYPE_PTR) then TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen) else TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end;
end;
end;
end else begin
TSessionCache.ReserveItem(ArrivalTime, OriginalSessionId, RemappedSessionId);
TDnsProtocolUtility.SetIdIntoPacket(RemappedSessionId, Buffer);
Forwarded := False;
for DnsServerIndex := 0 to (Configuration.MAX_NUM_DNS_SERVERS - 1) do begin
DnsServerConfiguration := TConfiguration.GetDnsServerConfiguration(DnsServerIndex);
if DnsServerConfiguration.IsEnabled then begin
if TConfiguration.IsDomainNameAffinityMatch(DomainName, DnsServerConfiguration.DomainNameAffinityMask) and TConfiguration.IsQueryTypeAffinityMatch(QueryType, DnsServerConfiguration.QueryTypeAffinityMask) then begin
if TDnsForwarder.ForwardDnsRequestForIPv4Udp(ServerCommunicationChannel, ArrivalTime, DnsServerIndex, DnsServerConfiguration, Buffer, BufferLen, RemappedSessionId) then begin
Forwarded := True;
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' forwarded to server ' + IntToStr(DnsServerIndex + 1) + '.');
end else begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Request ID ' + FormatCurr('00000', OriginalSessionId) + '>' + FormatCurr('00000', RemappedSessionId) + ' failed to be forwarded to server ' + IntToStr(DnsServerIndex + 1) + '.');
end;
end;
end;
end;
if Forwarded then begin
TSessionCache.InsertIPv4Item(ArrivalTime, OriginalSessionId, RemappedSessionId, RequestHash, Address, Port, False, False);
if THitLogger.IsEnabled and (Pos('F', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'F', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end else begin
if (QueryType = DNS_QUERY_TYPE_PTR) then TDnsProtocolUtility.BuildNegativeResponsePacket(DomainName, QueryType, Output, OutputLen) else TDnsProtocolUtility.BuildPositiveNullResponsePacket(DomainName, QueryType, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen, Address, Port);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' directly from resolver [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));
end;
end;
end;
end else begin
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Udp: Malformed packet received from client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' [' + TDnsProtocolUtility.PrintGenericPacketBytesAsStringFromPacket(Buffer, BufferLen) + '].');
end;
finally
TDnsResolver_Lock.Release;
end;
end;
end;
// --------------------------------------------------------------------------
//
// --------------------------------------------------------------------------
class procedure TDnsResolver.HandleDnsRequestForIPv4Tcp(ServerCommunicationChannel: TIPv4TcpCommunicationChannel; ArrivalTime: TDateTime; Buffer: Pointer; BufferLen: Integer; var Output: Pointer; var OutputLen: Integer; Address: TIPv4Address; Port: Word);
var
OriginalSessionId: Word; RequestHash: TMD5Digest; QueryType: Word; DomainName: String; IPv4Address: TIPv4Address; IPv6Address: TIPv6Address; RemappedSessionId: Word; DnsServerIndex: Integer; DnsServerConfiguration: TDnsServerConfiguration; Forwarded: Boolean;
begin
if (TDnsResolver_Lock <> nil) then begin
TDnsResolver_Lock.Acquire;
try
if (BufferLen >= MIN_DNS_PACKET_LEN) and (BufferLen <= MAX_DNS_PACKET_LEN) and TDnsProtocolUtility.IsValidRequestPacket(Buffer, BufferLen) then begin
OriginalSessionId := TDnsProtocolUtility.GetIdFromPacket(Buffer);
TDnsProtocolUtility.GetDomainNameAndQueryTypeFromRequestPacket(Buffer, BufferLen, DomainName, QueryType);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Tcp: Request ID ' + FormatCurr('00000', OriginalSessionId) + ' received from client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' [' + TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, True) + '].');
if (QueryType = DNS_QUERY_TYPE_A) then begin
if TDnsOverHttpsCache.FindIPv4Item(DomainName, IPv4Address) then begin
TDnsProtocolUtility.BuildPositiveIPv4ResponsePacket(DomainName, QueryType, IPv4Address, TConfiguration.GetGeneratedDnsResponseTimeToLive, Output, OutputLen);
TDnsProtocolUtility.SetIdIntoPacket(OriginalSessionId, Output); ServerCommunicationChannel.Send(Output, OutputLen);
if TTracer.IsEnabled then TTracer.Trace(TracePriorityInfo, 'TDnsResolver.HandleDnsRequestForIPv4Tcp: Response ID ' + FormatCurr('00000', OriginalSessionId) + ' sent to client ' + TIPv4AddressUtility.ToString(Address) + ':' + IntToStr(Port) + ' using dns over https cache [' + TDnsProtocolUtility.PrintResponsePacketDescriptionAsStringFromPacket(Output, OutputLen, True) + '].');
if THitLogger.IsEnabled and (Pos('X', THitLogger.GetFileWhat) > 0) then THitLogger.AddIPv4Hit(ArrivalTime, Address, 'X', '', '', TDnsProtocolUtility.PrintRequestPacketDescriptionAsStringFromPacket(DomainName, QueryType, Buffer, BufferLen, THitLogger.GetFullDump));