www.pudn.com > oicqspysrc.zip > IpHdr.pas

unit IpHdr; 
 
interface 
uses Windows,WinSock; 
type 
TIPHdr=record 
    ip_verlen:BYTE; 
    ip_tos:Byte; 
    ip_totallength:Word; 
    ip_id:Word; 
    ip_offset:Word; 
    ip_ttl:Byte; 
    ip_protocol:Byte; 
    ip_checksum:Word; 
    ip_srcaddr:DWORD; 
    ip_destaddr:DWORD; 
    end; 
PIPHdr=^TIPHdr; 
TUDPHdr=record 
    udp_srcport:Word; 
    udp_destport:Word; 
    udp_length:Word; 
    udp_checksum:Word; 
    end; 
PUDPHdr=^TUDPHdr; 
function inet_checksum(var buf;buflen:Integer):Word; 
function LookupName(const name:string;var addr:TInAddr):Boolean; 
implementation 
function LookupName(const name: string;var addr:TInAddr):Boolean; 
var 
  HostEnt: PHostEnt; 
begin 
  Result:=False; 
  addr.S_addr:=inet_addr(PChar(name)); 
  if(addr.S_addr=-1)then 
  begin 
    HostEnt := gethostbyname(PChar(Name)); 
    FillChar(Addr, SizeOf(Addr), 0); 
    if HostEnt <> nil then 
    begin 
      with addr, HostEnt^ do 
      begin 
        S_un_b.s_b1 := h_addr^[0]; 
        S_un_b.s_b2 := h_addr^[1]; 
        S_un_b.s_b3 := h_addr^[2]; 
        S_un_b.s_b4 := h_addr^[3]; 
      end; 
    Result:=True; 
    end; 
  end 
  else Result:=True; 
end; 
 
function inet_checksum(var buf;buflen:Integer):Word; 
var 
pBuf:PWord; 
cksum:DWORD; 
begin 
cksum:=0; 
pBuf:=PWord(buf); 
while(buflen>1)do 
    begin 
    cksum:=cksum+pBuf^; 
    Inc(pBuf); 
    Dec(buflen,SizeOf(Word)); 
    end; 
if(buflen<>0)then 
    begin 
    cksum:=cksum+pBuf^; 
    end; 
cksum:=(cksum shr 16)+(cksum and $ffff); 
cksum:=cksum shr 16; 
result:=not cksum; 
end; 
//--------------------------------------------- 
//USHORT checksum(USHORT *buffer, int size) 
//{ 
//    unsigned long cksum=0; 
// 
//    while (size > 1) 
//    { 
//        cksum += *buffer++; 
//        size  -= sizeof(USHORT); 
//    } 
//    if (size) 
//    { 
//        cksum += *(UCHAR*)buffer; 
//    } 
//    cksum = (cksum >> 16) + (cksum & 0xffff); 
//    cksum += (cksum >>16); 
// 
//    return (USHORT)(~cksum); 
//} 
//-------------------------------------------------- 
end.