[solved]binding socket 0.0.0.0, but cannot receive by 127.0.0.1
lazarus / 1-Linux

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rasberryrabbit · 2015-04-20 03:55

I make simple socket example app,
server binded '0.0.0.0' and client send '127.0.0.1'.
but server cannot received from anything '127.0.0.1' and only works
with '0.0.0.0'

what's I missing on this example?

Server

Code: [Select]procedure TMyThread.Execute;
const
  res = 'ok';
var
  laddr : sockaddr_in;
  lalen : TSocklen;
  buf : array[0..10] of char;
  rcv : Integer;
begin
  lalen:=sizeof(sockaddr_in);
  while not Terminated do begin
    rcv := fprecvfrom(sock,@buf[0],10,0,@laddr,@lalen);
    if rcv<>-1 then begin
      crti.Enter;
        mOutput:='recv: '+NetAddrToStr(laddr.sin_addr)+'
'+buf[0]+buf[1]+buf[2];
        Synchronize(@MsgOutput);
      if -1=fpsendto(sock,pchar(res),2,0,@laddr,sizeof(sockaddr_in))
then begin
        mOutput:='send error';
        Synchronize(@MsgOutput);
      end;
    end;
  end;
end;

Client

Code: [Select] sock:=fpsocket(PF_INET,SOCK_DGRAM, IPPROTO_UDP);
  fillchar(addr,sizeof(sockaddr_in),0);

  FpFcntl(sock, F_SetFl, O_NONBLOCK or fpfcntl(sock, F_GetFl, 0));
  if GetHostByName(Edit1.Text,host) then
    addr.sin_addr.s_addr:=host.Addr.s_addr
    else
       addr.sin_addr:=StrToHostAddr(Edit1.Text);
  addr.sin_port:=htons(30000);
  data:='123';
  if -1=fpsendto(sock,@data[1],3,0,@addr,sizeof(sockaddr_in)) then
    Memo1.Lines.Add('no send')
    else begin
      fpFD_ZERO(readset);
      fpFD_SET(sock,readset);
      buf[2]:=#0;
      slen := sizeof(sockaddr_in);
      if -1<>fpSelect(sock + 1, @readset, nil, nil, 2000) then begin
        if -1<>fprecvfrom(sock,@buf[0],30,0,@addr,@slen) then
          Memo1.Lines.Add(NetAddrToStr(addr.sin_addr)+'
'+pchar(@buf[0]));
      end;
    end;
  CloseSocket(sock);

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rasberryrabbit · 2015-04-20 08:08

It solved.

Code: [Select]  if GetHostByName(Edit1.Text,host) then
    addr.sin_addr.s_addr:=htonl(host.Addr.s_addr)
    else
       addr.sin_addr.s_addr:=htonl(StrToHostAddr(Edit1.Text).s_addr);

GetHostByName and StrToHostAddr returns reverse ordered IP Address.