郁闷的 原始UDP封包发送？？？

const

  IP_OPTIONS = 1 ;{ set/get IP options }

  IP_HDRINCL = 2 ;{ header is included with data }

  IP_TOS		 = 3 ;{ IP type of service and preced}

  IP_TTL		 = 4 ;{ IP time to live }



type

  IPHeader=record		// 20字节的IP头

    iphVerLen     :byte;      // 版本号和头长度（各占4位）

    ipTOS         :byte;          // 服务类型

    ipLength      :WORD;       // 封包总长度，即整个IP报的长度

    ipID          :WORD;			  // 封包标识，惟一标识发送的每一个数据报

    ipFlags       :WORD;	      // 标志

    ipTTL         :byte;	      // 生存时间，就是TTL

    ipProtocol    :byte;     // 协议，可能是TCP、UDP、ICMP等

    ipChecksum    :WORD;     // 校验和

    ipSource      :Cardinal;       // 源IP地址

    ipDestination :Cardinal;  // 目标IP地址

  end;

  PIPHeader=^IPHeader;



  UDPHeader = record

    sourcePort      :WORD;		// 源端口号

    destinationPort :WORD;    // 目的端口号

    len             :WORD;		// 封包长度

    checksum        :WORD;		// 校验和

  end;

  PUDPHeader=^UDPHeader;



....



function checksum(const Apc:PChar;Asize:integer):WORD;

var cksum:Cardinal;

    buff:array of char;

    Index:integer;

    W:WORD;

    b:byte;

begin

  Result:=0;



  SetLength(buff,Asize);

  CopyMemory(buff,Apc,Asize);



  cksum := 0;

  Index:=0;

  while (Asize>1) do

  begin

    CopyMemory(@W,@buff[Index],sizeof(W));

    cksum := cksum + W;

    Asize := Asize - sizeof(WORD);

    Index := Index + sizeof(WORD);

  end;

  // 是奇数

  if  (Asize mod 2)<>0 then

  begin

    CopyMemory(@b,@buff[Index],sizeof(b));

    cksum:=cksum + b;

  end;

  // 将32位的chsum高16位和低16位相加，然后取反

  cksum:=HIWORD(cksum)+LOWORD(cksum);

  cksum:=not cksum;

  Result:=cksum;

end;





{

计算UDP伪头校验和。UDP校验和基于如下几个域：

	源IP地址

	目的IP地址

	8位0域

	8位协议域

	16位UDP长度

	16位源端口号

	16位目的端口号

	16位UDP封包长度

	16位UDP校验和（0）

	UDP净荷

}

procedure ComputeUdpPseudoHeaderChecksum(

    pIphdr:PIPHeader;

    pUdphdr:PUDPHeader;

    payload:PChar;

    payloadlen:integer);

var buff:array[0..1023] of char;

    ptr:PChar;

    chksumlen:integer;

    zero:ULONG;

    i:integer;

begin

  ptr:=@buff;

  chksumlen := 0;

  zero := 0;



  // 包含源IP地址和目的IP地址

  CopyMemory(ptr,@pIpHdr.ipSource,sizeof(pIpHdr.ipSource));

  ptr:=ptr+sizeof(pIphdr.ipSource);

  chksumlen :=chksumlen+ sizeof(pIphdr.ipSource);



  CopyMemory(ptr, @pIphdr.ipDestination, sizeof(pIphdr.ipDestination));

  ptr :=ptr + sizeof(pIphdr.ipDestination);

  chksumlen :=chksumlen + sizeof(pIphdr.ipDestination);



  // 包含8位0域

	CopyMemory(ptr, @zero, 1);

	ptr :=ptr + 1;

	chksumlen := chksumlen + 1;



	// 协议

	CopyMemory(ptr, @pIphdr.ipProtocol, sizeof(pIphdr.ipProtocol));

	ptr := ptr + sizeof(pIphdr.ipProtocol);

	chksumlen := chksumlen + sizeof(pIphdr.ipProtocol);



	// UDP长度

	CopyMemory(ptr, @pUdphdr.len, sizeof(pUdphdr.len));

	ptr :=ptr + sizeof(pUdphdr.len);

	chksumlen :=chksumlen + sizeof(pUdphdr.len);



	// UDP源端口号

	CopyMemory(ptr, @pUdphdr.sourcePort, sizeof(pUdphdr.sourcePort));

	ptr := ptr + sizeof(pUdphdr.sourcePort);

	chksumlen := chksumlen + sizeof(pUdphdr.sourcePort);



	// UDP目的端口号

	CopyMemory(ptr, @pUdphdr.destinationPort, sizeof(pUdphdr.destinationPort));

	ptr :=ptr + sizeof(pUdphdr.destinationPort);

	chksumlen := chksumlen + sizeof(pUdphdr.destinationPort);



	// 又是UDP长度

	CopyMemory(ptr, @pUdphdr.len, sizeof(pUdphdr.len));

	ptr := ptr + sizeof(pUdphdr.len);

	chksumlen := chksumlen + sizeof(pUdphdr.len);



	// 16位的UDP校验和，置为0

	CopyMemory(ptr, @zero, sizeof(WORD));

	ptr :=ptr + sizeof(WORD);

	chksumlen :=chksumlen + sizeof(WORD);



	// 净荷

	CopyMemory(ptr, payload, payloadlen);

	ptr :=ptr + payloadlen;

	chksumlen :=chksumlen + payloadlen;



	// 补齐到下一个16位边界

	for i:=0 to payloadlen div 2 do

	begin

		ptr^ := chr(0);

		ptr:=ptr + 1;

		chksumlen:=chksumlen+1;

	end;

	// 计算这个校验和，将结果填充到UDP头

	pUdphdr.checksum := checksum(PChar(@buff), chksumlen);

end;



procedure TForm1.Button10Click(Sender: TObject);

var bIncl:bool;// 即 longbool;

    buff:array[0..1023] of char;

    pIpHdr:PIPHeader;

    pUdpHdr:PUDPHeader;

    destAddr:SOCKADDR_IN;

    nRet:integer;



    s,szSourceIp,szDestIp:string;

    nDestPort,nSourcePort:WORD;



    pData:PChar;

begin

  ZeroMemory(@buff,1024);



  szSourceIp:='192.168.2.137';

  szDestIp:='192.168.2.1';

  nDestPort:=53;

  nSourcePort:=1101;



  s:=#$00+#$02 +#$01+#$00 +#$00+#$01 +#$00+#$00 +#$00+#$00 +#$00+#$00

  +#$03 +'www' +#$03 +'163' +#$03 +'com' +#$00+#$00 +#$01+#$00 +#$01;



  Memo1.Lines.Add('length(s) : '+inttostr(length(s)));



  rawSocket:=socket(AF_INET,SOCK_RAW,IPPROTO_UDP);

  bIncl:=true;

  setsockopt(rawSocket,IPPROTO_IP,IP_HDRINCL,PChar(@bIncl),sizeof(bIncl));



  pIpHdr:=PIPHeader(@buff);

  pIpHdr.iphVerLen:= 4 shl 4 or (sizeof(IPHeader) div sizeof(ULONG));

  pIpHdr.ipLength:=htons(sizeof(IPHeader)+sizeof(UDPHeader)+length(s));

  pIpHdr.ipTTL:=128;

  pIpHdr.ipProtocol:=IPPROTO_UDP;

  pIpHdr.ipSource:=inet_addr(PChar(szSourceIp));

  pIpHdr.ipDestination:=inet_addr(PChar(szDestIp));

  pIpHdr.ipChecksum:=checksum(PChar(pIpHdr),sizeof(IPHeader));



  Memo1.Lines.Add('pIpHdr.ipChecksum : '+inttostr(pIpHdr.ipChecksum));



  pUdpHdr:=PUDPHeader(@buff[sizeof(IPHeader)]);

  pUdpHdr.sourcePort:=htons(nSourcePort);

  pUdpHdr.destinationPort:=htons(nDestPort);

  pUdpHdr.len:=htons(sizeof(UDPHeader)+length(s));

  pUdpHdr.checksum:=0;



  pData:=@buff[sizeof(IPHeader)+sizeof(UDPHeader)];

  CopyMemory(pData,PChar(s),length(s));

  ComputeUdpPseudoHeaderChecksum(pIpHdr,pUdpHdr,pData,length(s));



  Memo1.Lines.Add('pUdpHdr.checksum : '+inttostr(pUdpHdr.checksum));



  ZeroMemory(@destAddr,sizeof(SOCKADDR_IN));

  destAddr.sin_family:=AF_INET;

  destAddr.sin_port:=htons(nDestPort);

  destAddr.sin_addr.S_addr:=inet_addr(PChar(szDestIp));



  nRet:=sendto(rawSocket,buff,sizeof(IPHeader)+sizeof(UDPHeader)+length



(s),0,destAddr,sizeof(destAddr));

  if nRet=SOCKET_ERROR then

  begin

    nRet:=WSAGetLastError;

    memo1.Lines.Add('Send failed : '+inttostr(nRet));

  end

  else

    Memo1.Lines.Add('Send '+inttostr(nRet)+' bytes');



  CloseSocket(rawSocket);

end;

length(s) : 29

pIpHdr.ipChecksum : 55732

pUdpHdr.checksum : 8523

Send failed : 10049