Mod protocol
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Revision as of 16:24, 15 July 2007 by DavidXanatos (Talk | contribs)
Contents |
Under construction
THIS IS NOT FINAL.. feel free to edit.
Introduction
Modprot is needed for more clean protocol extensions by eMule modders....
The main idea is to set a bit in CT_EMULE_MISCOPTIONS2 in the initial hello. If that bit is set and receive by e eMule mod that is capable of processing extensions then that mod will send the options it is cabpale of in the response. and the first cleitn will also send back the protocol extensions it is capable of.
Important:
Clients that are not capable of processing the mod protocol(like official eMule/amule) will not set the mod bit in CT_EMULE_MISCOPTIONS2 and will never receive extended protocol information.
Documentation
All mod communication is to be done over the OP_MODPROT/OP_MODPACKEDPROT, When a hello(answer) with a set mod bit is received ConnectionEstablished is to be delayed, and instead the mod info packet with the opcode OP_MODINFO is ti be sent, ConnectionEstablished is to be triggered when the mod info packet is received.
A B Hello ---> MB Set (see ModBit is set) MB Set <--- Hello Answer ConEst <--- MInfo (Mod Info) MInfo ---> ConEst (call ConnectionEstablished)
The mod info packet have to contain eEmuleTags that announces supported features:
<uint 32> tag count <emule tag 1> <emule tag 2> ... <emule tag n>
Only mod features are allowed to use that what was announces by both sides, after the capability exchange all reminding opcodes > 0x01 (0x01 is mod info packet) are allowed to be used by clients in any way they want. All further communication is not part of this specification.
Protocol
Hello
Set the modbit ot in in CT_EMULE_MISCOPTIONS2
in baseclient.cpp, void CUpDownClient::SendHelloTypePacket(CSafeMemFile* data)
// eMule Misc. Options #2 const UINT uKadVersion = KADEMLIA_VERSION; const UINT uSupportLargeFiles = 1; const UINT uExtMultiPacket = 1; // Set the Mod Bit const UINT uModProt = 1; // mod bit // NEO: NMP - [NeoModProt] <-- Xanatos -- const UINT uSupportsCryptLayer = thePrefs.IsClientCryptLayerSupported() ? 1 : 0; const UINT uRequestsCryptLayer = thePrefs.IsClientCryptLayerRequested() ? 1 : 0; const UINT uRequiresCryptLayer = thePrefs.IsClientCryptLayerRequired() ? 1 : 0; const UINT uSupportsSourceEx2 = 1; CTag tagMisOptions2(CT_EMULE_MISCOPTIONS2, // (RESERVED ) (uSupportsSourceEx2 << 10) | (uRequiresCryptLayer << 9) | (uRequestsCryptLayer << 8) | (uSupportsCryptLayer << 7) | (uModProt << 6) | (uExtMultiPacket << 5) | (uSupportLargeFiles << 4) | (uKadVersion << 0) ); tagMisOptions2.WriteTagToFile(data);
Process hello.
baseclient.cpp bool CUpDownClient::ProcessHelloTypePacket(CSafeMemFile* data)
case CT_EMULE_MISCOPTIONS2:
// 21 Reserved
// 1 Supports SourceExachnge2 Packets, ignores SX1 Packet Version
// 1 Requires CryptLayer
// 1 Requests CryptLayer
// 1 Supports CryptLayer
// 1 Reserved (ModBit)
// 1 Ext Multipacket (Hash+Size instead of Hash)
// 1 Large Files (includes support for 64bit tags)
// 4 Kad Version
if (temptag.IsInt()) {
m_fSupportsSourceEx2 = (temptag.GetInt() >> 10) & 0x01;
m_fRequiresCryptLayer = (temptag.GetInt() >> 9) & 0x01;
m_fRequestsCryptLayer = (temptag.GetInt() >> 8) & 0x01;
m_fSupportsCryptLayer = (temptag.GetInt() >> 7) & 0x01;
// read the mod bit
m_fSupportsModProt = (temptag.GetInt() >> 6) & 0x01; // NEO: NMP - [NeoModProt] <-- Xanatos --
m_fExtMultiPacket = (temptag.GetInt() >> 5) & 0x01;
m_fSupportsLargeFiles = (temptag.GetInt() >> 4) & 0x01;
m_byKadVersion = (uint8)((temptag.GetInt() >> 0) & 0x0f);
dwEmuleTags |= 8;
if (bDbgInfo)
m_strHelloInfo.AppendFormat(_T("\n KadVersion=%u, LargeFiles=%u ExtMultiPacket=%u CryptLayerSupport=%u CryptLayerRequest=%u CryptLayerRequires=%u m_fSupportsSourceEx2=%u"), m_byKadVersion, m_fSupportsLargeFiles, m_fExtMultiPacket, m_fSupportsCryptLayer, m_fRequestsCryptLayer, m_fRequiresCryptLayer, m_fSupportsSourceEx2);
m_fRequestsCryptLayer &= m_fSupportsCryptLayer;
m_fRequiresCryptLayer &= m_fRequestsCryptLayer;
Send hello answer and modprot info
Listensocket.cpp bool CClientReqSocket::ProcessPacket(const BYTE* packet, uint32 size, UINT opcode)
if (client->GetHashType() == SO_EMULE && !bIsMuleHello)
client->SendMuleInfoPacket(false);
client->SendHelloAnswer();
if (client)
{
// NEO: NMP - [NeoModProt] -- Xanatos -->
if(client->GetNeoModProtVersion())
client->SendModInfoPacket();
Example of sendmoinfopacket:
void CUpDownClient::SendModInfoPacket(){
if (socket == NULL){ // first we chack if we have a valid socket, actualy we was called form the socket so this check is rather unnesesery, but in case
ASSERT(0);
return;
}
CSafeMemFile data(128);
// write the amount of emule tags we intent to send
// !!! this value must be correct !!!
uint32 tagcount=2;
// write the first tag (Nr.1)
// in this sample its an normal tag with an uint8 ID, its the modstring 0x55 = 'T'
data.WriteUInt32(tagcount); // nr. of tags
CTag tagPartStatus(0x55,_T("TestMod"));
tagPartStatus.WriteNewEd2kTag(&data);
// write the secund tag (Nr.2)
// in this sample its an custom named tag with an string as ID
CTag tagMyMail("Mod:eMail",_T("User@Domain.com"));
tagMyMail.WriteNewEd2kTag(&data);
// we are done writing tags
// now we create a packet and put what we have writen in it
Packet* packet = new Packet(&data,OP_MODPROT);
packet->opcode = OP_MODINFOPACKET;
if (thePrefs.GetDebugClientTCPLevel() > 0)
DebugSend("OP__ModInfoPacket", this);
theStats.AddUpDataOverheadOther(packet->size);
socket->SendPacket(packet,true,true); // we send the packet
}
delay ConnectionEstablished & send mod info packet
listensocket.cpp
bool CClientReqSocket::ProcessPacket(const BYTE* packet, uint32 size, UINT opcode)
{
try
{
try
{
if (!client && opcode != OP_HELLO)
{
theStats.AddDownDataOverheadOther(size);
throw GetResString(IDS_ERR_NOHELLO);
}
else if (client && opcode != OP_HELLO && opcode != OP_HELLOANSWER)
client->CheckHandshakeFinished();
switch(opcode)
{
case OP_HELLOANSWER:
{
theStats.AddDownDataOverheadOther(size);
client->ProcessHelloAnswer(packet,size);
if (thePrefs.GetDebugClientTCPLevel() > 0){
DebugRecv("OP_HelloAnswer", client);
Debug(_T(" %s\n"), client->DbgGetHelloInfo());
}
// NEO: NMP - [NeoModProt] -- Xanatos -->
if(client->GetNeoModProtVersion() == 0)
// we will start the SUI when we recieve the mod info packet
// NEO: NMP END <-- Xanatos --
// start secure identification, if
// - we have received OP_EMULEINFO and OP_HELLOANSWER (old eMule)
// - we have received eMule-OP_HELLOANSWER (new eMule)
if (client->GetInfoPacketsReceived() == IP_BOTH)
client->InfoPacketsReceived();
if (client)
{
// NEO: NMP - [NeoModProt] -- Xanatos -->
if (client->GetNeoModProtVersion())
client->SendModInfoPacket();
else // we will call ConnectionEstablished when we recieve the Mod Info
// NEO: NMP END <-- Xanatos --
{
client->ConnectionEstablished();
theApp.emuledlg->transferwnd->clientlistctrl.RefreshClient(client);
}
}
break;
}
case OP_HELLO:
{
theStats.AddDownDataOverheadOther(size);
[...........................]
client->SendHelloAnswer();
if (client)
{
// NEO: NMP - [NeoModProt] -- Xanatos -->
if(client->GetNeoModProtVersion())
client->SendModInfoPacket();
else // we will call ConnectionEstablished when we recieve the Mod Info
// NEO: NMP END <-- Xanatos --
client->ConnectionEstablished();
}
ASSERT( client );
if(client)
{
// NEO: NMP - [NeoModProt] -- Xanatos -->
// we will start the SUI when we recieve the mod info packet
if(client->GetNeoModProtVersion() == 0)
// NEO: NMP END <-- Xanatos --
// start secure identification, if
// - we have received eMule-OP_HELLO (new eMule)
if (client->GetInfoPacketsReceived() == IP_BOTH)
client->InfoPacketsReceived();
if( client->GetKadPort() )
Kademlia::CKademlia::Bootstrap(ntohl(client->GetIP()), client->GetKadPort(), (client->GetKadVersion() > 1));
}
break;
}
process modinfo packet
listensocket.cpp
bool CClientReqSocket::ProcessModPacket(const BYTE* packet, uint32 size, UINT opcode, UINT uRawSize)
{
try
{
try
{
if (!client)
{
theStats.AddDownDataOverheadOther(uRawSize);
throw GetResString(IDS_ERR_UNKNOWNCLIENTACTION);
}
if (thePrefs.m_iDbgHeap >= 2)
ASSERT_VALID(client);
switch(opcode)
{
case OP_MODINFOPACKET:
{
if (thePrefs.GetDebugClientTCPLevel() > 0)
DebugRecv("OP__ModInfoPacket", client);
theStats.AddDownDataOverheadOther(uRawSize);
if(client->GetNeoModProtVersion() == 0)
throw CString(_T("Recieved Neo Mod Info Packet from a cleint whitch doe snot support this feature!"));
client->ProcessModInfoPacket(packet,size);
// Now after we have all informations about the cleint the connection is established
client->ConnectionEstablished();
// start secure identification, if
// - we have received OP_MODINFOPACKET, (Neo Compatible new eMule mods)
if (client->GetInfoPacketsReceived() == IP_BOTH)
client->InfoPacketsReceived();
break;
}
// NEO: NMPm - [NeoModProtMultiPacket]
case OP_MODMULTIPACKET:
{
...
baseclient.cpp
void CUpDownClient::ProcessModInfoPacket(const uchar* pachPacket, uint32 nSize)
{
bool bDbgInfo = thePrefs.GetUseDebugDevice();
CString m_strModInfo;
CSafeMemFile data(pachPacket, nSize);
uint32 tagcount = data.ReadUInt32();
if (bDbgInfo)
m_strModInfo.AppendFormat(_T(" Tags=%u"), (UINT)tagcount);
for (uint32 i = 0; i < tagcount; i++)
{
CTag temptag(&data, false);
switch (temptag.GetNameID())
{
case CT_NEO_FEATURES:
if (temptag.IsInt()){
// = (uint8)(temptag.GetInt() >> 24) & 0xff;
// = (uint8)(temptag.GetInt() >> 20) & 0x0f;
#ifdef NATTUNNELING // NEO: NATT - [NatTraversal]
// = (uint8)(temptag.GetInt() >> 18) & 0x03;
m_PublicPortReport = (uint8)(temptag.GetInt() >> 17) & 0x01; // NEO: RTP - [ReuseTCPPort]
m_SupportsNatTraversal = (uint8)(temptag.GetInt() >> 16) & 0x01;
// = (uint8)(temptag.GetInt() >> 15) & 0x01; // NEO: XSB - [XSBuddy]
#endif //NATTUNNELING // NEO: NATT END
m_NeoXSVersion = (uint8)(temptag.GetInt() >> 12) & 0x07; // NEO: NXS - [NeoXS]
// = (uint8)(temptag.GetInt() >> 10) & 0x03;
m_LowIDUDPPingSupport = (uint8)(temptag.GetInt() >> 9 ) & 0x01;
m_UnsolicitedPartStatus = (uint8)(temptag.GetInt() >> 8 ) & 0x01;
// = (uint8)(temptag.GetInt() >> 4 ) & 0x0f;
// = (uint8)(temptag.GetInt() >> 0 ) & 0x0f;
}else if (bDbgInfo)
m_strHelloInfo.AppendFormat(_T("\n ***UnkType=%s"), temptag.GetFullInfo());
break;
case CT_EXT_FILESTATUS:
if (temptag.IsInt()){
// X-ToDo
// = (uint8)(temptag.GetInt() >> 24) & 0xff;
// = (uint8)(temptag.GetInt() >> 16) & 0xff;
//uint8 BlockedPartStatus = (uint8)(temptag.GetInt() >> 15) & 0x01;
//uint8 HidenPartStatus = (uint8)(temptag.GetInt() >> 14) & 0x01;
//uint8 RealPartStatusVer = (uint8)(temptag.GetInt() >> 11) & 0x07;
m_IncompletePartVer = (uint8)(temptag.GetInt() >> 8 ) & 0x07;
// = (uint8)(temptag.GetInt() >> 4 ) & 0x0f;
m_SubChunksVer = (uint8)(temptag.GetInt() >> 0 ) & 0x0f;
//ASSERT(BlockedPartStatus || HidenPartStatus || !RealPartStatusVer);
// Note: RPC version without one or booth RPS flags is invalid,
// the cleint must always say wha is he doint gith the parts 'blocking and hiding' or 'only hiding',
// or he can booth depanding on the situation
// Booth RPS versions have always teh same version as the writing functions are identical
// just other opcodes are used and other part states notifyed
//if(BlockedPartStatus)
// m_BlockedPartStatusVer = RealPartStatusVer;
//if(HidenPartStatus)
// m_HidenPartStatusVer = RealPartStatusVer;
}else if (bDbgInfo)
m_strModInfo.AppendFormat(_T("\n ***UnkType=%s"), temptag.GetFullInfo());
break;
#ifdef NATTUNNELING // NEO: NATT - [NatTraversal]
case CT_EMULE_BUDDYID:
if(temptag.IsHash())
{
SetBuddyID(temptag.GetHash());
}
else{
if (bDbgInfo)
m_strModInfo.AppendFormat(_T("\n ***UnkType=%s"), temptag.GetFullInfo());
}
break;
#endif //NATTUNNELING // NEO: NATT END
default:
// Named tag test begin
if(strcmp(temptag.GetName(),"Mod:Hello") == 0)
{
if(temptag.IsStr())
Log(LOG_SUCCESS,_T("*** Greathings from %s: %s"),GetUserName(),temptag.GetStr());
}
else
// Named tag test end
if (bDbgInfo)
m_strModInfo.AppendFormat(_T("\n ***UnkTag=%s"), temptag.GetFullInfo());
}
}
proces mod data example
listensocket.cpp bool CClientReqSocket::PacketReceivedCppEH(Packet* packet)
// NEO: NMP - [NeoModProt] -- Xanatos -->
case OP_MODPACKEDPROT:
if (!packet->UnPackPacket()){
if (thePrefs.GetVerbose())
AddDebugLogLine(false, _T("Failed to decompress client Mod TCP packet; %s; %s"), DbgGetClientTCPPacket(packet->prot, packet->opcode, packet->size), DbgGetClientInfo());
bResult = false;
break;
}
case OP_MODPROT:
bResult = ProcessModPacket((const BYTE*)packet->pBuffer, packet->size, packet->opcode, uRawSize);
break;
// NEO: NMP - [NeoModProt] -- Xanatos -->
bool CClientReqSocket::ProcessModPacket(const BYTE* packet, uint32 size, UINT opcode, UINT uRawSize)
{
try
{
try
{
if (!client)
{
theStats.AddDownDataOverheadOther(uRawSize);
throw GetResString(IDS_ERR_UNKNOWNCLIENTACTION);
}
if (thePrefs.m_iDbgHeap >= 2)
ASSERT_VALID(client);
switch(opcode)
{
case OP_MODINFOPACKET:
{
if (thePrefs.GetDebugClientTCPLevel() > 0)
DebugRecv("OP__ModInfoPacket", client);
theStats.AddDownDataOverheadOther(uRawSize);
if(client->GetNeoModProtVersion() == 0)
throw CString(_T("Recieved Neo Mod Info Packet from a cleint whitch doe snot support this feature!"));
client->ProcessModInfoPacket(packet,size);
// Now after we have all informations about the cleint the connection is established
client->ConnectionEstablished();
// start secure identification, if
// - we have received OP_MODINFOPACKET, (Neo Compatible new eMule mods)
if (client->GetInfoPacketsReceived() == IP_BOTH)
client->InfoPacketsReceived();
break;
}
default:
theStats.AddDownDataOverheadOther(uRawSize);
PacketToDebugLogLine(_T("ModProt"), packet, size, opcode);
}
}
catch(CFileException* error)
{
error->Delete();
throw GetResString(IDS_ERR_INVALIDPACKAGE);
}
catch(CMemoryException* error)
{
error->Delete();
throw CString(_T("Memory exception"));
}
}
catch(CString error)
{
if (thePrefs.GetVerbose() && !error.IsEmpty())
DebugLogWarning(_T("Error: %s - while processing Mod packet: opcode=%s size=%u; %s"), error, DbgGetMuleClientTCPOpcode(opcode), size, DbgGetClientInfo());
// Note: don't disconnect cleints on mod prot errors, the extensions are just addons and if thay fail the client will work anyway
//if (client)
// client->SetDownloadState(DS_ERROR, _T("ProcessModPacket error. ") + error);
//Disconnect(_T("ProcessModPacket error. ") + error);
//return false;
}
return true;
}
// NEO: NMP END <-- Xanatos --
backward compatibility
Modstring is still send and replied in hello packet to maintain backward compatibility. However a opcode for modstring will be defined for those who also want to move it to the mod protocol. A mod using the modbit MUST identify itself. (A mod that uses extensions but refuses to identify itslef CAN be considered a bad mod by some antileecher systems)
OPCODES
OP_MODPROT 0x57 OP_MODPACKEDPROT 0x58 OP_MODINFOPACKET 0x01
TAGS defines
Tags used must be reserved in modprot topic at emule-project.net. Source must be published withing 3 months for claiming a tag.
A mod can claim only up to 4 tags, BUT with capabilty bit in a tag this should be MORE than enough! If you need more you are dowin something wrong probably. Note that also string tags are available that are not regulated.
only tags in the rage from 0x20 (space) - 0x7e are to be used in this version of modprot.
TODO: add more detailded cescriptoin of these tags.
| TAGNAME | VALUE | Meaning | Reserved by / source code |
|---|---|---|---|
| MISC_PROTOCOL_EXTENSIONS | 'M' 4D | (etc..) | |
| FILE_STATUS_EXTENSIONS | 'S' 53 | (SCT, ICS, etc..) | |
| NEO_PROTOCOL_EXTENSIONS | 'N' 4E | (NatT, NeoXS, etc..) | |
| EMULE_BUDDYID | '@' 40 | - | |
| CT_MOD_VERSION | 'U' 0x55 | Modstring. Modstring MUST be sent either in hello OR Modprotocol (note that sending it in mod protocol is not backward compatible) |
See also
References to emule protocol...
