DNSResolve.pas

   1 {
   2    Copyright (C) 2010-2018 MegaBrutal
   3
   4    This unit is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This unit is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 }
  17
  18
  19 {$MODE FPC}
  20
  21 unit DNSResolve;
  22
  23 interface
  24 uses WinSock, Sockets, ctypes;
  25
  26 const
  27
  28    NI_NOFQDN         =     $01;
  29    NI_NUMERICHOST    =     $02;
  30    NI_NAMEREQD       =     $04;
  31    NI_NUMERICSERV    =     $08;
  32    NI_DGRAM          =     $10;
  33
  34
  35 type
  36
  37    PAddrInfo = ^TAddrInfo;
  38    TAddrInfo = record
  39       ai_flags: cint;
  40       ai_family: cint;
  41       ai_socktype: cint;
  42       ai_protocol: cint;
  43       ai_addrlen: size_t;
  44       ai_canonname: PChar;
  45       ai_addr: PSockAddr;
  46       ai_next: PAddrInfo;
  47    end;
  48
  49    TGAIResult = record
  50       GAIError: integer;
  51       AddrInfo: PAddrInfo;
  52    end;
  53
  54
  55    function getaddrinfo(NodeName, ServiceName: PChar; Hints: PAddrInfo; var AddrInfo: PAddrInfo): cint; stdcall;
  56       external 'ws2_32.dll' name 'getaddrinfo';
  57
  58    procedure freeaddrinfo(AddrInfo: PAddrInfo); stdcall;
  59       external 'ws2_32.dll' name 'freeaddrinfo';
  60
  61    function getnameinfo(SockAddr: PSockAddr; SockAddrLength: cuint32; NodeBuffer: PChar; NodeBufferSize: cuint32;
  62       ServiceBuffer: PChar; ServiceBufferSize: cuint32; Flags: cint): cint; stdcall;
  63       external 'ws2_32.dll' name 'getnameinfo';
  64
  65    function ResolveHost(HostName: ansistring; Family: cint): TGAIResult;
  66    procedure FreeHost(var GAIResult: TGAIResult);
  67    function ResolveIP(AddrInfo: PAddrInfo; Flags: cint): ansistring; overload;
  68    function ResolveIP(AddrInfo: PAddrInfo): ansistring; overload;
  69    function ResolveIP(SockAddr: PSockAddr; Flags: cint): ansistring; overload;
  70    function ResolveIP(SockAddr: PSockAddr): ansistring; overload;
  71    function IPToStr(SockAddr: PSockAddr): ansistring;
  72
  73
  74 implementation
  75
  76
  77 function ResolveHost(HostName: ansistring; Family: cint): TGAIResult;
  78 var hint: TAddrInfo;
  79 begin
  80    FillByte(hint, SizeOf(hint), 0);
  81    with hint do begin
  82       ai_family:= Family;
  83       ai_socktype:= SOCK_STREAM;
  84       ai_protocol:= IPPROTO_TCP;
  85    end;
  86    ResolveHost.GAIError:= getaddrinfo(PChar(HostName), nil, @hint, ResolveHost.AddrInfo);
  87 end;
  88
  89 procedure FreeHost(var GAIResult: TGAIResult);
  90 begin
  91    if GAIResult.AddrInfo <> nil then begin
  92       freeaddrinfo(GAIResult.AddrInfo);
  93       GAIResult.AddrInfo:= nil;
  94    end;
  95 end;
  96
  97 function ResolveIP(AddrInfo: PAddrInfo; Flags: cint): ansistring;
  98 var
  99    r: integer;
 100    NodeBuffer: array[0..255] of char;
 101 begin
 102    NodeBuffer[0]:= #0;
 103    r:= getnameinfo(AddrInfo^.ai_addr, AddrInfo^.ai_addrlen, @NodeBuffer, SizeOf(NodeBuffer), nil, 0, Flags);
 104    if r = 0 then ResolveIP:= PChar(@NodeBuffer)
 105    else ResolveIP:= IPToStr(AddrInfo^.ai_addr);
 106 end;
 107
 108 function ResolveIP(AddrInfo: PAddrInfo): ansistring;
 109 begin
 110    ResolveIP:= ResolveIP(AddrInfo, 0);
 111 end;
 112
 113 function ResolveIP(SockAddr: PSockAddr; Flags: cint): ansistring;
 114 var
 115    AddrInfo: TAddrInfo;
 116 begin
 117    AddrInfo.ai_addr:= SockAddr;
 118
 119    if SockAddr^.sa_family = AF_INET then
 120       AddrInfo.ai_addrlen:= SizeOf(TSockAddr)
 121    else if SockAddr^.sa_family = AF_INET6 then
 122       AddrInfo.ai_addrlen:= SizeOf(TSockAddr6)
 123    else
 124       AddrInfo.ai_addrlen:= 0;
 125
 126    ResolveIP:= ResolveIP(PAddrInfo(@AddrInfo), Flags);
 127 end;
 128
 129 function ResolveIP(SockAddr: PSockAddr): ansistring;
 130 begin
 131    ResolveIP:= ResolveIP(SockAddr, 0);
 132 end;
 133
 134 function IPToStr(SockAddr: PSockAddr): ansistring;
 135 begin
 136 {$IFNDEF GNI}
 137    if SockAddr^.sa_family = AF_INET then
 138       IPToStr:= NetAddrToStr(SockAddr^.sin_addr)
 139    else if SockAddr^.sa_family = AF_INET6 then
 140       IPToStr:= NetAddrToStr6(PSockAddr6(SockAddr)^.sin6_addr)
 141    else
 142       IPToStr:= 'unknown';
 143 {$ELSE}
 144    IPToStr:= ResolveIP(SockAddr, NI_NUMERICHOST);
 145 {$ENDIF}
 146 end;
 147
 148
 149 end.