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{ Copyright (C) 2005 Bas Steendijk and Peter Green
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For conditions of distribution and use, see copyright notice in zlib_license.txt
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which is included in the package
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----------------------------------------------------------------------------- }
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unit dnssync;
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{$ifdef fpc}
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{$mode delphi}
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{$endif}
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{$include lcoreconfig.inc}
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interface
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uses
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dnscore,
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binipstuff,
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{$ifdef mswindows}
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winsock,
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windows,
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{$else}
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{$ifdef VER1_0}
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linux,
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{$else}
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baseunix,unix,unixutil,
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{$endif}
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sockets,
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fd_utils,
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{$endif}
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lcorernd,
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sysutils,
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ltimevalstuff;
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//convert a name to an IP
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//will return v4 or v6 depending on what seems favorable, or manual preference setting
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//on error the binip will have a family of 0 (other fields are also currently
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//zeroed out but may be used for further error information in future)
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//timeout is in milliseconds, it is ignored when using windows dns
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function forwardlookup(name:ansistring;timeout:integer):tbinip;
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//convert a name to a list of all IP's returned
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//this returns both v4 and v6 IP's, or possibly only v4 or v6, depending on settings
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//on error, returns an empty list
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function forwardlookuplist(name:ansistring;timeout:integer):tbiniplist;
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//convert an IP to a name, on error a null string will be returned, other
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//details as above
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function reverselookup(ip:tbinip;timeout:integer):ansistring;
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const
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tswrap=$4000;
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tsmask=tswrap-1;
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numsock=1{$ifdef ipv6}+1{$endif};
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defaulttimeout=10000;
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const mintimeout=16;
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toport='53';
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implementation
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{$ifdef mswindows}
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uses dnswin;
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{$endif}
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{$ifndef mswindows}
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{$define syncdnscore}
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{$endif}
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{$i unixstuff.inc}
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type tdnsstatearr=array[0..numsock-1] of tdnsstate;
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{$ifdef syncdnscore}
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{$ifdef mswindows}
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const
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winsocket = 'wsock32.dll';
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function sendto(s: TSocket; const Buf; len, flags: Integer; var addrto: TinetSockAddrV; tolen: Integer): Integer; stdcall; external winsocket name 'sendto';
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function bind(s: TSocket; var addr: TinetSockAddrV; namelen: Integer): Longbool; stdcall; external winsocket name 'bind';
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type
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fdset=tfdset;
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{$endif}
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function getts:integer;
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{$ifdef mswindows}
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begin
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result := GetTickCount and tsmask;
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{$else}
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var
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temp:ttimeval;
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begin
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gettimeofday(temp);
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result := ((temp.tv_usec div 1000) + (temp.tv_sec * 1000)) and tsmask;
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{$endif}
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end;
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procedure resolveloop(timeout:integer;var state:tdnsstatearr;numsockused:integer);
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var
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selectresult : integer;
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fds : fdset;
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endtime : longint;
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starttime : longint;
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wrapmode : boolean;
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currenttime : integer;
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lag : ttimeval;
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selecttimeout : ttimeval;
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socknum:integer;
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needprocessing:array[0..numsock-1] of boolean;
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finished:array[0..numsock-1] of boolean;
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a,b:integer;
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Src : TInetSockAddrV;
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Srcx : {$ifdef mswindows}sockaddr_in{$else}TInetSockAddrV{$endif} absolute Src;
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SrcLen : Integer;
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fromip:tbinip;
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fromport:ansistring;
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fd:array[0..numsock-1] of integer;
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toaddr:array[0..numsock-1] of tbinip;
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id:integer;
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sendquerytime:array[0..numsock-1] of integer;
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procedure setupsocket;
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var
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inAddrtemp : TInetSockAddrV;
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biniptemp:tbinip;
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a,retrycount,porttemp:integer;
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bindresult:boolean;
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begin
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biniptemp := getcurrentsystemnameserverbin(id);
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//must get the DNS server here so we know to init v4 or v6
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if biniptemp.family = AF_INET6 then biniptemp := ipstrtobinf('::') else biniptemp := ipstrtobinf('0.0.0.0');
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for a := 0 to numsockused-1 do begin
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retrycount := 5;
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repeat
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if (retrycount <= 1) then begin
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porttemp := 0; //for the last attempt let the OS decide
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end else begin
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porttemp := 1024 + randominteger(65536 - 1024);
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end;
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makeinaddrv(biniptemp,inttostr( porttemp ),inaddrtemp);
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fd[a] := Socket(biniptemp.family,SOCK_DGRAM,0);
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bindresult := {$ifdef mswindows}Not{$endif} Bind(fd[a],inAddrtemp,inaddrsize(inaddrtemp));
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dec(retrycount);
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until (retrycount <= 0) or (bindresult);
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If (not bindresult) Then begin
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{$ifdef mswindows}
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raise Exception.create('unable to bind '+inttostr(WSAGetLastError));
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{$else}
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raise Exception.create('unable to bind '+inttostr(socketError));
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{$endif}
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end;
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end;
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end;
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procedure cleanupsockets;
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var
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a:integer;
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begin
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for a := 0 to numsockused-1 do closesocket(fd[a]);
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end;
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function sendquery(socknum:integer;const packet:tdnspacket;len:integer):boolean;
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var
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ip : tbinip;
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port : ansistring;
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inaddr : TInetSockAddrV;
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begin
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{ writeln('sendquery ',decodename(state.packet,state.packetlen,12,0,a),' ',state.requesttype);}
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result := false;
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if len = 0 then exit; {no packet}
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ip := getcurrentsystemnameserverbin(id);
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{$ifdef ipv6}{$ifdef mswindows}
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if toaddr[socknum].family = AF_INET6 then if (useaf = 0) then useaf := useaf_preferv6;
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{$endif}{$endif}
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port := toport;
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toaddr[socknum] := ip;
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makeinaddrv(toaddr[socknum],port,inaddr);
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sendto(fd[socknum],packet,len,0,inaddr,inaddrsize(inaddr));
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sendquerytime[socknum] := getts;
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result := true;
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end;
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begin
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if timeout < mintimeout then timeout := defaulttimeout;
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starttime := getts;
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endtime := starttime + timeout;
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if (endtime and tswrap)=0 then begin
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wrapmode := false;
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end else begin
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wrapmode := true;
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end;
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endtime := endtime and tsmask;
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setupsocket;
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for socknum := 0 to numsockused-1 do begin
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needprocessing[socknum] := true;
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finished[socknum] := false;
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end;
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repeat
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for socknum := numsockused-1 downto 0 do if needprocessing[socknum] then begin
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state_process(state[socknum]);
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case state[socknum].resultaction of
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action_ignore: begin
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{do nothing}
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end;
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action_done: begin
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finished[socknum] := true;
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//exit if all resolvers are finished
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b := 0;
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for a := 0 to numsockused-1 do begin
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if finished[a] then inc(b);
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end;
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if (b = numsockused) then begin
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cleanupsockets;
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exit;
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end;
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//onrequestdone(self,0);
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end;
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action_sendquery:begin
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{ writeln('send query');}
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sendquery(socknum,state[socknum].sendpacket,state[socknum].sendpacketlen);
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end;
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end;
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needprocessing[socknum] := false;
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end;
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currenttime := getts;
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msectotimeval(selecttimeout, (endtime-currenttime) and tsmask);
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fd_zero(fds);
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for socknum := numsockused-1 downto 0 do if not finished[socknum] then fd_set(fd[socknum],fds);
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if (selecttimeout.tv_sec > 0) or (selecttimeout.tv_usec > retryafter) then begin
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selecttimeout.tv_sec := 0;
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selecttimeout.tv_usec := retryafter;
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end;
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//find the highest of the used fd's
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b := 0;
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for socknum := numsockused-1 downto 0 do if fd[socknum] > b then b := fd[socknum];
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selectresult := select(b+1,@fds,nil,nil,@selecttimeout);
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if selectresult > 0 then begin
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currenttime := getts;
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for socknum := numsockused-1 downto 0 do if fd_isset(fd[socknum],fds) then begin
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{ writeln('selectresult>0');}
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//why the hell are we zeroing out the packet buffer before reading into it?! --plugwash
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fillchar(state[socknum].recvpacket,sizeof(state[socknum].recvpacket),0);
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msectotimeval(lag,(currenttime-sendquerytime[socknum]) and tsmask);
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reportlag(id,(lag.tv_sec*1000000)+lag.tv_usec);
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SrcLen := SizeOf(Src);
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state[socknum].recvpacketlen := recvfrom(fd[socknum],state[socknum].recvpacket, SizeOf(state[socknum].recvpacket),0,Srcx,SrcLen);
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if (state[socknum].recvpacketlen > 0) then begin
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fromip := inaddrvtobinip(Src);
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fromport := inttostr(htons(src.InAddr.port));
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if ((not comparebinip(toaddr[socknum],fromip)) or (fromport <> toport)) then begin
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// writeln('dnssync received from wrong IP:port ',ipbintostr(fromip),'#',fromport);
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state[socknum].recvpacketlen := 0;
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end else begin
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state[socknum].parsepacket := true;
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needprocessing[socknum] := true;
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end;
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end;
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end;
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end;
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if selectresult < 0 then exit;
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if selectresult = 0 then begin
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currenttime := getts;
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reportlag(id,-1);
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if (currenttime >= endtime) and ((not wrapmode) or (currenttime < starttime)) then begin
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cleanupsockets;
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exit;
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end else begin
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//resend
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for socknum := numsockused-1 downto 0 do begin
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sendquery(socknum,state[socknum].sendpacket,state[socknum].sendpacketlen);
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end;
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end;
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end;
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until false;
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end;
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{$endif}
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function forwardlookuplist(name:ansistring;timeout:integer):tbiniplist;
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var
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dummy : integer;
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a:integer;
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biniptemp:tbinip;
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l:tbiniplist;
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numsockused:integer;
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state:tdnsstatearr;
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begin
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ipstrtobin(name,biniptemp);
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if biniptemp.family <> 0 then begin
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result := biniplist_new;
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biniplist_add(result,biniptemp);
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exit; //it was an IP address, no need for dns
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end;
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{$ifdef mswindows}
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if usewindns then begin
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if (useaf = useaf_v4) then a := af_inet else if (useaf = useaf_v6) then a := af_inet6 else a := 0;
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result := winforwardlookuplist(name,a,dummy);
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{$ifdef ipv6}
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if (useaf = useaf_preferv4) then begin
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{prefer mode: sort the IP's}
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l := biniplist_new;
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addipsoffamily(l,result,af_inet);
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addipsoffamily(l,result,af_inet6);
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result := l;
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end;
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if (useaf = useaf_preferv6) then begin
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{prefer mode: sort the IP's}
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l := biniplist_new;
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addipsoffamily(l,result,af_inet6);
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addipsoffamily(l,result,af_inet);
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result := l;
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end;
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{$endif}
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end else
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{$endif}
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begin
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{$ifdef syncdnscore}
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{$ifdef ipv6}initpreferredmode;{$endif}
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numsockused := 0;
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result := biniplist_new;
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if (useaf <> useaf_v6) then begin
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setstate_forward(name,state[numsockused],af_inet);
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inc(numsockused);
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end;
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{$ifdef ipv6}
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if (useaf <> useaf_v4) then begin
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setstate_forward(name,state[numsockused],af_inet6);
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inc(numsockused);
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end;
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{$endif}
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resolveloop(timeout,state,numsockused);
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if (numsockused = 1) then begin
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biniplist_addlist(result,state[0].resultlist);
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{$ifdef ipv6}
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end else if (useaf = useaf_preferv6) then begin
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biniplist_addlist(result,state[1].resultlist);
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biniplist_addlist(result,state[0].resultlist);
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end else begin
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biniplist_addlist(result,state[0].resultlist);
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biniplist_addlist(result,state[1].resultlist);
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{$endif}
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end;
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{$endif}
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end;
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end;
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function forwardlookup(name:ansistring;timeout:integer):tbinip;
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var
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listtemp:tbiniplist;
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begin
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listtemp := forwardlookuplist(name,timeout);
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result := biniplist_get(listtemp,0);
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end;
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function reverselookup(ip:tbinip;timeout:integer):ansistring;
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var
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dummy : integer;
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numsockused:integer;
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state:tdnsstatearr;
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begin
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{$ifdef mswindows}
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if usewindns then begin
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result := winreverselookup(ip,dummy);
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exit;
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| 405 |
end;
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| 406 |
{$endif}
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| 407 |
{$ifdef syncdnscore}
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| 408 |
setstate_reverse(ip,state[0]);
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numsockused := 1;
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resolveloop(timeout,state,numsockused);
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result := state[0].resultstr;
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{$endif}
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end;
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| 414 |
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| 415 |
{$ifdef mswindows}
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| 416 |
var
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| 417 |
wsadata : twsadata;
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| 418 |
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initialization
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| 420 |
WSAStartUp($2,wsadata);
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| 421 |
finalization
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| 422 |
WSACleanUp;
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| 423 |
{$endif}
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| 424 |
end.
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