Il 26/05/2011 15:28, Éric Fleming Bonilha ha scritto:
> Hi Emanuele,
>
> Thanks for the examples
>
> I actually have a working application with multicast, but I was
> wondering if it was correct, because I tested it with a switch that
> manages IGMP and no multicast groups were being created.
>
> I saw that you set TTL to 32, why? The default 1 would not work? I know
> that 1 would work just on local network (My case)
I used multicast on wan. Our customer wanted this setting.
>
> What I´m confused is with the group creation, how my ICS based
> application with create a multicast group that is visible for switches
> (By using IGMP) and switches can manage this multicast distribution?
> Without that, multicast would be just like broadcast.
>
Using wireshark, when a multicast socket enter in listening state, you
should see igmp packets on the net.
These packets should tell to the switch how to manage multicast
distribution.
> I saw on TWSocket source that when I start listening it actually sets
> the socket to ADD_MEMBERSHIP tp the group, this may be OK for receiving
> data, but I´m confused about sending multicast data, because the sender
> is the one that was supposed to create the multicast group right? But to
> send multicast data on network I need to use Connect method instead of
> Listen from the TWSocket, in this case, on Connect method I didn´t find
> a mention to ADD_MEMBERSHIP or creating a multicast group.
In my implementation, I start listening also for the sender, using
TUDP.SetTx and TUDP.StartRx methods. I use TUDP.Connect method, only for
send udp unicast packets.
I'm not a multicast expert. I found this kind of solution that worked in
my scenario.
Using my implementation, what kind of packet distribution do you get?
Broadcast?
Bye
>
> Thanks
> Eric
>
>
> -----Mensagem Original----- From: emanuele bizzarri
> Sent: Thursday, May 26, 2011 3:41 AM
> To: twsocket@elists.org
> Subject: Re: [twsocket] Multicast question
>
> Hi,
> this is an example of TUDP class that can be used in multicast (receive
> and transmit).
> This unit depends by other units, but you can easily extract what you need.
> Note that I set multicast ttl.
> I hope it will be usefull for you,
> Bye
> Emanuele
>
>
> unit ewPlatform_UDP;
>
> interface
>
> uses
> ewPlatform_Lists,
> ewPlatform_Logger,
> ewPlatform_Memory,
> ewPlatform_Packets,
> ewPlatform_Strings,
> OverByteIcsWsocket,
> WinSock,
> Windows,
> SysUtils,
> Classes;
>
> type
> TOnUDPError=procedure(aError:integer)of object;
> TOnUDPDataSent=procedure(aInteger:integer)of object;
>
> TOnUDPDataAvailable=procedure(aSender:TObject;aData:pointer;aSize:integer;aPeerIP:string;aPeerPort:integer)
>
> of object;
> TUDP=class
> protected
> fWS:TWSocket;
> fSent:boolean;
> fPeerSrc:TSockAddr;
> fPeerSrcLen:integer;
> fRxData:pointer;
> fRxSize:integer;
> fWhiteList:TStringList;
> fBlackList:TStringList;
> fTxList:TStringList;
> procedure DataAvailable(aSender:TObject;aError:word);
> procedure DataSent(aSender:TObject;aErrCode:word);
> procedure DnsLookupDone(aSender:TObject;aErrCode:word);
> procedure ChangeState(aSender:TObject;aOldState,aNewState:TSocketState);
> procedure Send;
> function GetStarted:boolean;
> public
> pLocalIP:string;
> pLocalPort:integer;
> pPeerIP:string;
> pPeerPort:integer;
> pMultiThreaded:boolean;
> pMulticast:boolean;
> pUseWhiteList:boolean;
> pUseBlackList:boolean;
> pMulticastTTL:integer;
>
> pGetPeerByData:boolean;
> pOnDataSent:TOnUDPDataSent;
> pOnDataAvailable:TOnUDPDataAvailable;
> pOnError:TOnUDPError;
> pOnChangeState:TChangeState;
>
> constructor Create;
> destructor Destroy;override;
> procedure StartRx;
> procedure SetTx;
> procedure Disconnect;
> procedure Connect;
> function Add2WhiteList(aIPPort:string):boolean;
> function Add2BlackList(aIPPort:string):boolean;
> procedure DeleteFromWhiteList(aIPPort:string);
> procedure DeleteFromBlackList(aIPPort:string);
> procedure ClearWhiteList;
> procedure ClearBlackList;
> function NewData(aData:pointer;aSize:integer):integer;
>
> property pStarted:boolean read GetStarted;
>
> end;
>
> implementation
>
> //------------------------------------------------------------------------------
>
> //TUDP
> //------------------------------------------------------------------------------
>
> constructor TUDP.Create;
> begin
> inherited Create;
> TLogger.Log('UDP socket creation
> threadID='+inttostr(GetCurrentThreadID),lsVerbose,true);
> fWS:=TWSocket.Create(nil);
> fWS.OnDataAvailable:=DataAvailable;
> fWS.OnDataSent:=DataSent;
> fWS.OnDnsLookupDone:=DnsLookUpDone;
> fWS.OnChangeState:=ChangeState;
> fWS.Proto:='udp';
>
> pGetPeerByData:=false;
> fTxList:=TStringList.Create;
> fSent:=false;
>
> pLocalIP:='0.0.0.0';
> pLocalPort:=0;
> pPeerIP:='';
> pPeerPort:=0;
> pMultiThreaded:=false;
> pMulticast:=false;
> pMulticastTTL:=32;
>
> fWhiteList:=TStringList.Create;
> fBlackList:=TStringList.Create;
> pUseWhiteList:=false;
> pUseBlackList:=false;
>
> fRxSize:=256*1024;
> getmem(fRxData,fRxSize);
>
> fPeerSrcLen:=sizeof(fPeerSrc);
> end;
>
> destructor TUDP.Destroy;
> begin
> Disconnect;
> FreeObjAndNil(fWS);
> FreeMemAndNil(fRxData);
> FreeObjAndNil(fWhiteList);
> FreeObjAndNil(fBlackList);
> FreeList(fTxList);
> FreeObjAndNil(fTxList);
> inherited Destroy;
> end;
>
> procedure TUDP.StartRx;
> begin
> Disconnect;
> pLocalIP:=trim(pLocalIP);
> if (pLocalIP<>'')and(pLocalPort>0) then
> begin
> fWS.Proto:='udp';
> fWS.MultiThreaded:=pMultiThreaded;
> fWS.Addr:=pLocalIP;
> fWS.Port:=inttostr(pLocalPort);
> if fWS.Addr='' then
> fWS.Addr:='0.0.0.0';
> if pMulticast then
> begin
> fWS.MultiCast:=true;
> fWS.ReuseAddr:=true;
> fWS.MultiCastAddrStr:=pPeerIP;
> end;
> fWS.Listen;
> fWS.SocketRcvBufSize:=fRXSize;
> if pMulticast then
>
> setsockopt(fWS.HSocket,IPPROTO_IP,IP_MULTICAST_TTL,@pMulticastTTL,sizeof(pMulticastTTL));
>
> end
> else
> TLogger.Log('UDP socket start rx error LocalIP='+pLocalIP+'
> LocalPort='+inttostr(pLocalPort),lsError,true);
> end;
>
> function TUDP.GetStarted:boolean;
> begin
> result:=false;
> if (assigned(fWS)) then
> result:=(fWS.State=wsListening)or(fWS.State=wsConnected);
> end;
>
> procedure TUDP.SetTx;
> var
> lRes:boolean;
> begin
> pPeerIP:=trim(pPeerIP);
> lRes:=(pPeerIp<>'')and(pPeerPort>0);
> TLogger.Log('UDP socket set tx PeerIP='+pPeerIP+'
> PeerPort='+inttostr(pPeerPort)+'...
> '+Boolean2Str(lRes,'ok','ko'),Boolean2Severity(lRes,lsVerbose,lsError),true);
>
> fPeerSrc.sin_family:=AF_INET;
> fPeerSrc.sin_addr.s_addr:=WSocket_inet_addr(AnsiString(pPeerIP));
> fPeerSrc.sin_port:=htons(word(pPeerPort));
> fSent:=false;
> FreeList(fTxList);
> end;
>
> procedure TUDP.Disconnect;
> begin
> fWS.Shutdown(SD_BOTH);
> fWS.Close;
> FreeList(fTxList);
> fSent:=false;
> end;
>
> procedure TUDP.Connect;
> begin
> Disconnect;
> fWS.Proto:='udp';
> fWS.MultiThreaded:=pMultiThreaded;
> fWS.LocalAddr:=pLocalIP;
> fWS.Addr:=trim(pPeerIP);
> fWS.Port:=inttostr(pPeerPort);
> SetTx;
> if (fWS.Addr<>'')and(pPeerPort>0) then
> fWS.DnsLookup(fWS.Addr);
> end;
>
> procedure TUDP.DnsLookupDone(aSender:TObject;aErrCode:word);
> begin
> //se riesco a risolvere l'host mi connetto
> if aErrCode=0 then
> begin
> fWS.Connect;
> fWS.SocketRcvBufSize:=fRXSize;
> end;
> end;
>
> procedure
> TUDP.ChangeState(aSender:TObject;aOldState,aNewState:TSocketState);
> begin
> if assigned(pOnChangeState) then
> pOnChangeState(self,aOldState,aNewState);
> end;
>
> function TUDP.NewData(aData:pointer;aSize:integer):integer;
> var
> lItem:TBufferItem;
> begin
> result:=0;
> if (pPeerIP<>'')and(GetStarted) then
> begin
> lItem:=TBufferItem.Create(aData,aSize,0,0);
> fTxList.AddObject(inttostr(aSize),lItem);
> Send;
> end;
> end;
>
> procedure TUDP.Send;
> var
> lItem:TBufferItem;
> begin
> if (not fSent)and(fTxList.Count>0) then
> begin
> lItem:=TBufferItem(fTxList.Objects[0]);
> if (fWS.SendTo(fPeerSrc,fPeerSrcLen,lItem.pData,lItem.pSize)>0)or
> (WSocket_WSAGetLastError=WSAEWOULDBLOCK)
> then
> fSent:=true;
> end;
> end;
>
> procedure TUDP.DataSent(aSender:TObject;aErrCode:word);
> var
> lItem:TBufferItem;
> lSize:integer;
> begin
> if fSent then
> begin
> fSent:=false;
> lSIze:=0;
> if fTxList.Count>0 then
> begin
> lItem:=TBufferItem(fTxList.Objects[0]);
> if assigned(lItem) then
> begin
> lSize:=lItem.pSize;
> FreeObjAndNil(lItem);
> end;
> fTxList.Delete(0);
> end;
> if assigned(pOnDataSent) then
> pOnDataSent(lSize);
> Send;
> end;
> end;
>
> procedure TUDP.DataAvailable(aSender:TObject;aError:word);
> var
> lSize:integer;
> lPeerSrc:TSockAddrIn;
> lPeerSrcLen:integer;
> lPeerIP:string;
> lPeerPort:integer;
> lValidPeer:boolean;
> begin
> lPeerSrcLen:=sizeof(lPeerSrc);
> lSize:=fWS.ReceiveFrom(fRxData,fRxSize-2,lPeerSrc,lPeerSrcLen);
> if lSize<0 then
> begin
> {
> WSAEWOULDBLOCK=10035
> Resource temporarily unavailable.
> This error is returned from operations on nonblocking sockets that
> cannot
> be completed immediately, for example recv when no data is queued to be
> read from the socket. It is a nonfatal error, and the operation
> should be
> retried later. It is normal for WSAEWOULDBLOCK to be reported as the
> result from calling connect on a nonblocking SOCK_STREAM socket,
> since some time must elapse for the connection to be established.
> }
> {
> WSAECONNRESET=10054
> Connection reset by peer.
> An existing connection was forcibly closed by the remote host. This
> normally
> results if the peer application on the remote host is suddenly stopped,
> the host is rebooted, the host or remote network interface is disabled,
> or the remote host uses a hard close (see setsockopt for more
> information on the SO_LINGER option on the remote socket). This
> error may
> also result if a connection was broken due to keep-alive activity
> detecting a
> failure while one or more operations are in progress. Operations that
> were in progress fail with WSAENETRESET. Subsequent operations
> fail with WSAECONNRESET.
> }
> if assigned(pOnError) then
> pOnError(WSocket_WSAGetLastError);
> end
> else
> begin
> lPeerIP:=string(AnsiString(inet_ntoa(lPeerSrc.sin_addr)));
> lPeerPort:=ntohs(lPeerSrc.sin_port);
>
> if pGetPeerByData then
> begin
> pGetPeerByData:=false;
> pPeerIP:=lPeerIP;
> pPeerPort:=lPeerPort;
> SetTx;
> end;
> lValidPeer:=true;
> if pUseWhiteList then
> begin
>
> lValidPeer:=(fWhiteList.IndexOf(lPeerIP+':'+inttostr(lPeerPort))>=0)or(fWhiteList.IndexOf(lPeerIP+':*')>=0);
>
> end;
> if (lValidPeer)and(pUseBlackList) then
>
> lValidPeer:=(fBlackList.IndexOf(lPeerIP+':'+inttostr(lPeerPort))<0)and(fBlackList.IndexOf(lPeerIP+':*')<0);
>
> if lValidPeer then
> begin
> PAnsiChar(fRxData)[lSize]:=#0;
> PAnsiChar(fRxData)[lSize+1]:=#0;
> if assigned(pOnDataAvailable) then
> pOnDataAvailable(self,fRxData,lSize,lPeerIP,lPeerPort);
> end;
> end;
> end;
>
> function TUDP.Add2WhiteList(aIPPort:string):boolean;
> begin
> result:=false;
> DeleteFromBlackList(aIPPort);
> if fWhiteList.IndexOf(aIPPort)<0 then
> begin
> fWhiteList.Add(aIPPort);
> result:=true;
> end;
> end;
>
> function TUDP.Add2BlackList(aIPPort:string):boolean;
> begin
> result:=false;
> DeleteFromWhiteList(aIPPort);
> if fBlackList.IndexOf(aIPPort)<0 then
> begin
> fBlackList.Add(aIPPort);
> result:=true;
> end;
> end;
>
> procedure TUDP.DeleteFromWhiteList(aIPPort:string);
> var
> lIndex:integer;
> begin
> lIndex:=fWhiteList.IndexOf(aIPPort);
> if lIndex>=0 then
> fWhiteList.Delete(lIndex);
> end;
>
> procedure TUDP.DeleteFromBlackList(aIPPort:string);
> var
> lIndex:integer;
> begin
> lIndex:=fBlackList.IndexOf(aIPPort);
> if lIndex>=0 then
> fBlackList.Delete(lIndex);
> end;
>
> procedure TUDP.ClearWhiteList;
> begin
> fWhiteList.Clear;
> end;
>
> procedure TUDP.ClearBlackList;
> begin
> fBlackList.Clear;
> end;
>
> end.
>
> Il 26/05/2011 06:48, Éric Fleming Bonilha ha scritto:
>> Hi
>>
>> I´m wondering how to use ICS properly to send and receive Multicast
>> data. Where can I find example for multicast and ICS?
>>
>> I´m in doubt about the IGMP protocol, do I need to implement anything
>> on application layer or does IGMP protocol is implemented on
>> underlying stack automatically?
>>
>> How my application will create a multicast group on network and/or
>> join a group?
>>
>> Thank you very much!
>> Eric
>> --
>> To unsubscribe or change your settings for TWSocket mailing list
>> please goto http://lists.elists.org/cgi-bin/mailman/listinfo/twsocket
>> Visit our website at http://www.overbyte.be
>
--
Ing. Emanuele Bizzarri
Software Development Department
e-works s.r.l.
41011 - Campogalliano - Modena - Italy
tel. +39 059 2929081 int. 23
fax +39 059 2925035
e-mail: e.bizza...@e-works.it - http://www.e-works.it
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