CentrED

(*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License, Version 1.0 only

 * (the "License").  You may not use this file except in compliance

 * with the License.

 *

 * You can obtain a copy of the license at

 * http://www.opensource.org/licenses/cddl1.php.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at

 * http://www.opensource.org/licenses/cddl1.php.  If applicable,

 * add the following below this CDDL HEADER, with the fields enclosed

 * by brackets "[]" replaced with your own identifying * information:

 *      Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 *

 *

 *      Portions Copyright 2007 Andreas Schneider

 *)

unit UPacketHandlers;

interface

uses

  Classes, SysUtils, dzlib, math, UConfig, UNetState, UEnhancedMemoryStream, UEnums,

  ULinkedList, URegions;

type

  TPacketProcessor = procedure(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

  TPacketProcessorMethod = procedure(ABuffer: TEnhancedMemoryStream; ANetState: TNetState) of object;

  { TPacketHandler }

  TPacketHandler = class(TObject)

    constructor Create(ALength: Cardinal; APacketProcessor: TPacketProcessor); overload;

    constructor Create(ALength: Cardinal; APacketProcessorMethod: TPacketProcessorMethod); overload;

    procedure Process(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

  protected

    FLength: Cardinal;

    FPacketProcessor: TPacketProcessor;

    FPacketProcessorMethod: TPacketProcessorMethod;

  published

    property PacketLength: Cardinal read FLength;

  end;

var

  PacketHandlers: array[0..$FF] of TPacketHandler;

function ValidateAccess(ANetState: TNetState; ALevel: TAccessLevel): Boolean; overload;

function ValidateAccess(ANetState: TNetState; ALevel: TAccessLevel; AX, AY: Cardinal): Boolean; overload;

procedure RegisterPacketHandler(AID: Byte; APacketHandler: TPacketHandler);

implementation

uses

  UCEDServer, UPackets, UConnectionHandling, UAdminHandling, UClientHandling;

function ValidateAccess(ANetState: TNetState; ALevel: TAccessLevel): Boolean;

begin

  Result := (ANetState.Account <> nil) and (ANetState.Account.AccessLevel >= ALevel);

end;

function ValidateAccess(ANetState: TNetState; ALevel: TAccessLevel; AX, AY: Cardinal): Boolean;

var

  i,j: Word;

  region: TRegion;

  rect: TRect;

begin

  if not ValidateAccess(ANetState, ALevel) then Exit(False);

  if (ANetState.Account.Regions.Count = 0) or

    (ANetState.Account.AccessLevel >= alAdministrator) then Exit(True); //no restrictions

  Result := False;

  for i := 0 to ANetState.Account.Regions.Count - 1 do

  begin

    region := Config.Regions.Find(ANetState.Account.Regions[i]);

    if region <> nil then

    begin

      for j := 0 to region.Areas.Count - 1 do

      begin

        rect := region.Areas.Rects[j];

        if InRange(AX, rect.Left, rect.Right) and

          InRange(AY, rect.Top, rect.Bottom) then

          Exit(True);

      end;

    end;

  end;

end;

procedure RegisterPacketHandler(AID: Byte; APacketHandler: TPacketHandler);

begin

  if Assigned(PacketHandlers[AID]) then FreeAndNil(PacketHandlers[AID]);

  PacketHandlers[AID] := APacketHandler;

end;

{ TPacketHandler }

constructor TPacketHandler.Create(ALength: Cardinal; APacketProcessor: TPacketProcessor);

begin

  inherited Create;

  FLength := ALength;

  FPacketProcessor := APacketProcessor;

  FPacketProcessorMethod := nil;

end;

constructor TPacketHandler.Create(ALength: Cardinal;

  APacketProcessorMethod: TPacketProcessorMethod);

begin

  inherited Create;

  FLength := ALength;

  FPacketProcessor := nil;

  FPacketProcessorMethod := APacketProcessorMethod;

end;

procedure TPacketHandler.Process(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

begin

  if Assigned(FPacketProcessor) then

    FPacketProcessor(ABuffer, ANetState)

  else if Assigned(FPacketProcessorMethod) then

    FPacketProcessorMethod(ABuffer, ANetState);

end;

procedure OnCompressedPacket(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

var

  uncompStream: TEnhancedMemoryStream;

  uncompBuffer: TDecompressionStream;

  targetSize: Cardinal;

  packetID: Byte;

begin

  targetSize := ABuffer.ReadCardinal;

  uncompBuffer := TDecompressionStream.Create(ABuffer);

  uncompStream := TEnhancedMemoryStream.Create;

  try

    uncompStream.CopyFrom(uncompBuffer, targetSize);

    uncompStream.Position := 0;

    packetID := uncompStream.ReadByte;

    if PacketHandlers[packetID] <> nil then

    begin

      if PacketHandlers[PacketID].PacketLength = 0 then

        uncompStream.Position := uncompStream.Position + 4;

      uncompStream.Lock(uncompStream.Position, uncompStream.Size - uncompStream.Position);

      PacketHandlers[PacketID].Process(uncompStream, ANetState);

      uncompStream.Unlock;

    end else

    begin

      Writeln(TimeStamp, 'Dropping client due to unknown packet: ', ANetState.Socket.PeerAddress);

      ANetState.ReceiveQueue.Clear;

      CEDServerInstance.Disconnect(ANetState.Socket);

    end;

  finally

    if uncompBuffer <> nil then uncompBuffer.Free;

    if uncompStream <> nil then uncompStream.Free;

  end;

end;

procedure OnRequestBlocksPacket(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

var

  coords: TBlockCoordsArray;

begin

  if not ValidateAccess(ANetState, alView) then Exit;

  SetLength(coords, (ABuffer.Size - ABuffer.Position) div SizeOf(TBlockCoords));

  ABuffer.Read(coords[0], Length(coords) * SizeOf(TBlockCoords));

  CEDServerInstance.SendPacket(ANetState, TCompressedPacket.Create(TBlockPacket.Create(coords, ANetState)));

end;

procedure OnFreeBlockPacket(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

var

  x, y: Word;

  blockSubscriptions: TLinkedList;

begin

  if not ValidateAccess(ANetState, alView) then Exit;

  x := ABuffer.ReadWord;

  y := ABuffer.ReadWord;

  blockSubscriptions := CEDServerInstance.Landscape.BlockSubscriptions[X, Y];

  if blockSubscriptions <> nil then

  begin

    blockSubscriptions.Delete(ANetState);

    ANetState.Subscriptions.Remove(blockSubscriptions);

  end;

end;

procedure OnNoOpPacket(ABuffer: TEnhancedMemoryStream; ANetState: TNetState);

begin

  //no operation

end;

{$WARNINGS OFF}

var

  i: Integer;

initialization

  for i := 0 to $FF do

    PacketHandlers[i] := nil;

  PacketHandlers[$01] := TPacketHandler.Create(0, @OnCompressedPacket);

  PacketHandlers[$02] := TPacketHandler.Create(0, @OnConnectionHandlerPacket);

  PacketHandlers[$03] := TPacketHandler.Create(0, @OnAdminHandlerPacket);

  PacketHandlers[$04] := TPacketHandler.Create(0, @OnRequestBlocksPacket);

  PacketHandlers[$05] := TPacketHandler.Create(5, @OnFreeBlockPacket);

  //$06-$0B handled by landscape

  PacketHandlers[$0C] := TPacketHandler.Create(0, @OnClientHandlerPacket);

  //$0D handled by radarmap

  //$0E handled by landscape

  PacketHandlers[$FF] := TPacketHandler.Create(1, @OnNoOpPacket);

finalization

  for i := 0 to $FF do

    if PacketHandlers[i] <> nil then

      PacketHandlers[i].Free;

{$WARNINGS ON}

end.