---  In DownloadClient.cpp

/* They make a source request this way..*/
SOURCECLIENTREASK )))){
		
		Packet* packet = new Packet(OP_REQUESTSOURCES,16,OP_EMULEPROT);
		memcpy(packet->pBuffer,reqfile->GetFileHash(),16);
		socket->SendPacket(packet,true,true);
		reqfile->m_ClientSrcAsked = ((::GetTickCount() -SOURCECLIENTREASK) + 6000);
	}


--- In ListenSocket.cpp

 			case OP_REQUESTSOURCES:{
				if (size != 16)
					throw GetResString(IDS_ERR_BADSIZE);
				CKnownFile* file = theApp.sharedfiles->GetFileByID((uchar*)packet);
				if (!file)
					file = theApp.downloadqueue->GetFileByID((uchar*)packet);
				if (file){
					Packet* tosend = file->CreateSrcInfoPacket(client);
					if (tosend){
						SendPacket(tosend,true,true);
					}
				}
				break;
			}
 			case OP_ANSWERSOURCES:{
				try{
					CSafeMemFile data((BYTE*)packet,size);
					uchar hash[16];
					data.Read(hash,16);
					CKnownFile* file = theApp.downloadqueue->GetFileByID((uchar*)packet);
					if (!file)
						file = theApp.sharedfiles->GetFileByID((uchar*)packet);
					if (file && file->IsPartFile()){
						((CPartFile*)file)->AddClientSources(&data);
					}
				}
				catch(CFileException* error){
					OUTPUT_DEBUG_TRACE();
					error->Delete();
					throw GetResString(IDS_ERR_INVALIDPACKAGE);
				}
				break;
			}


--- In opcodes.h

#define OP_EMULEPROT		0xC5			/* Evil */
#define OP_MLDONKEYPROT	0x00

// extened prot client <-> extened prot client
#define	OP_EMULEINFO		0x01
#define	OP_EMULEINFOANSWER	0x02
#define OP_COMPRESSEDPART	0x40
#define OP_QUEUERANKING		0x60
#define OP_FILEDESC		0x61
#define OP_VERIFYUPSREQ		0x71
#define OP_VERIFYUPSANSWER	0x72
#define OP_UDPVERIFYUPREQ	0x73
#define OP_UDPVERIFYUPA		0x74
#define OP_REQUESTSOURCES	0x81			/*Interesting opcodes..*/
#define OP_ANSWERSOURCES	0x82			/*Interesting opcodes..*/

// extened prot client <-> extened prot client UDP
#define OP_REASKFILEPING	0x90
#define OP_REASKACK			0x91
#define OP_FILENOTFOUND		0x92
#define OP_QUEUEFULL		0x93