Delphi用Socket IP/UDP局域网广播

 A类互联网网址： 7位网络号          24位主机号
              01111111.11111111.11111111.11111111 --->01111111 = 127
               0..127  0..255   0..255   0..255
               0.0.0.0 -- 127.255.255.255
B类互联网网址： 14位网络号          16位主机号
              10111111.11111111.11111111.11111111 --->10111111 = 191
               128..191  0..255   0..255   0..255
               128.0.0.0 -- 191.255.255.255
C类互联网网址： 21位网络号          8位主机号
              11011111.11111111.11111111.11111111 --->11011111 = 223
               192..223  0..255   0..255   0..255
               192.0.0.0 -- 223.255.255.255
多播地址： 224.0.0.0 -- 255.255.255.255

 

 

const MCASTADDR = ’234.5.6.7’; MCASTPORT = 25000; LOCAL_PORT = 5555; WM_SOCKET = WM_USER + 55;type TForm1 = class(TForm) Button1: TButton; Edit1: TEdit; ListBox1: TListBox; CheckBox1: TCheckBox; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure FormClose(Sender: TObject; var Action: TCloseAction); private { Private declarations } procedure WMSocket(var Msg: TMessage); message WM_SOCKET; public { Public declarations } end;var Form1: TForm1;implementation{$R *.dfm}procedure ErrMsg( msg: string );begin MessageBox( 0, PChar(msg), ’Ping Program Error’, MB_ICONERROR );end;procedure TForm1.WMSocket(var Msg: TMessage);var buf:array[0..255]of char; remote:TSockaddr; len:integer; p:string;begin case WSAGetSelectEvent( Msg.LParam ) of FD_READ : begin recvfrom(msg.WParam, buf[0], 255,0, remote, len ); getpeername( msg.WParam, remote, len ); p := inet_ntoa(remote.sin_addr) + ’ Port: ’ + inttostr(ntohs(remote.sin_port)); listbox1.Items.Add(p + buf); end; end;end;procedure TForm1.FormCreate(Sender: TObject);var wsa : TWSAData;begin if WSAStartup( $0202, wsa ) <> 0 then ErrMsg( ’Windows socket is not responed.’ ); listbox1.Font.Name := ’Courier New’; listbox1.Font.Size := 9;end;procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);begin if WSACleanup <> 0 then ErrMsg( ’Windows socket can not be closed.’ );end;procedure TForm1.Button1Click(Sender: TObject);var sock : TSocket; local, remote : TSockAddr; bufsend : Array[0..31]of char; ret,i : s32; ttl, opt : s32; bSender :bool; mcast :ip_mreq;begin bSender := CheckBox1.Checked; sock := socket( AF_INET, SOCK_DGRAM, 0 ); if sock = INVALID_SOCKET then begin ErrMsg( ’socket Failed: ’ + IntToStr(WSAGetLastError) ); exit; end; local.sin_family := AF_INET; local.sin_port := htons(u16(MCASTPort)); local.sin_addr.S_addr := inet_addr(’192.168.1.12’); // if bind( sock, @local, SizeOf(local) )= SOCKET_ERROR then begin ErrMsg( ’bind Failed: ’ + IntToStr(WSAGetLastError) ); closesocket(sock); exit; end; if WSAAsyncSelect( sock, Handle, WM_SOCKET, FD_READ ) = socket_error then begin ErrMsg( ’WSAAsyncSelect Failed: ’ + IntToStr(WSAGetLastError) ); closesocket(sock); exit; end; remote.sin_family := AF_INET; remote.sin_port := htons( MCASTPort ); remote.sin_addr.S_addr := inet_addr(MCASTADDR); mcast.imr_multiaddr.S_addr := remote.sin_addr.S_addr; mcast.imr_interface.S_addr := local.sin_addr.S_addr; if setsockopt( sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, @mcast, sizeof(mcast) )=SOCKET_ERROR then begin ErrMsg( ’setsockopt Failed: ’ + IntToStr(WSAGetLastError) ); closesocket(sock); exit; end; Opt := 8; if setsockopt( sock, IPPROTO_IP, IP_MULTICAST_TTL, @opt, sizeof(opt) )=SOCKET_ERROR then begin ErrMsg( ’setsockopt Failed: ’ + IntToStr(WSAGetLastError) ); closesocket(sock); exit; end; //要发送的UDP数据 FillChar( bufSend, 32, ’C’ ); if bSender then for i:=0 to 3 do begin ret :=sendto( sock, bufsend[0], 32, 0, remote, sizeof(remote)); if ret =socket_error then begin ErrMsg( ’sendto Failed: ’ + IntToStr(WSAGetLastError) ); //closesocket(sock); break; end; end; //closesocket( sock ); // closesocket(sockm);end;