OpenVPN: Add packet scrambling/obfuscation feature

This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.
The XOR mask set on the server has to be the same on the client, otherwise it will not be able to connect with certain obfuscation modes.
A special OpenVPN client built with the "XOR patch" is required in order to use this function, because it has never been merged in the official OpenVPN repository.

Two parameters are added to the server configuration: "OpenVPNObfuscationMethod" and "OpenVPNObfuscationMask".
Their value can be retrieved with "OpenVpnObfuscationGet" and set with "OpenVpnObfuscationEnable" in the VPN Command Line Management Utility.

src/Cedar/Admin.c

@@ -8919,6 +8919,8 @@ void InOpenVpnSstpConfig(OPENVPN_SSTP_CONFIG *t, PACK *p)
 	t->EnableOpenVPN = PackGetBool(p, "EnableOpenVPN");
 	t->EnableSSTP = PackGetBool(p, "EnableSSTP");
 	PackGetStr(p, "OpenVPNPortList", t->OpenVPNPortList, sizeof(t->OpenVPNPortList));
+	t->OpenVPNObfuscation= PackGetBool(p, "OpenVPNObfuscation");
+	PackGetStr(p, "OpenVPNObfuscationMask", t->OpenVPNObfuscationMask, sizeof(t->OpenVPNObfuscationMask));
 }
 void OutOpenVpnSstpConfig(PACK *p, OPENVPN_SSTP_CONFIG *t)
 {
@@ -8931,6 +8933,8 @@ void OutOpenVpnSstpConfig(PACK *p, OPENVPN_SSTP_CONFIG *t)
 	PackAddBool(p, "EnableOpenVPN", t->EnableOpenVPN);
 	PackAddBool(p, "EnableSSTP", t->EnableSSTP);
 	PackAddStr(p, "OpenVPNPortList", t->OpenVPNPortList);
+	PackAddBool(p, "OpenVPNObfuscation", t->OpenVPNObfuscation);
+	PackAddStr(p, "OpenVPNObfuscationMask", t->OpenVPNObfuscationMask);
 }
 
 // DDNS_CLIENT_STATUS

src/Cedar/Cedar.h

@@ -1076,7 +1076,9 @@ typedef struct CEDAR
 	UINT FifoBudget;				// Fifo budget
 	SSL_ACCEPT_SETTINGS SslAcceptSettings;	// SSL Accept Settings
 	UINT DhParamBits;  // Bits of Diffie-Hellman parameters
-	char OpenVPNDefaultClientOption[MAX_SIZE];	// OpenVPN Default Client Option String
+	char OpenVPNDefaultClientOption[MAX_SIZE];	// OpenVPN: Default Client Option String
+	bool OpenVPNObfuscation;					// OpenVPN: Obfuscation mode
+	char OpenVPNObfuscationMask[MAX_SIZE];		// OpenVPN: String (mask) for XOR obfuscation
 } CEDAR;
 
 // Type of CEDAR

src/Cedar/Command.c

@@ -7573,6 +7573,8 @@ void PsMain(PS *ps)
 			{"OpenVpnEnable", PsOpenVpnEnable},
 			{"OpenVpnGet", PsOpenVpnGet},
 			{"OpenVpnMakeConfig", PsOpenVpnMakeConfig},
+			{"OpenVpnObfuscationEnable", PsOpenVpnObfuscationEnable},
+			{"OpenVpnObfuscationGet", PsOpenVpnObfuscationGet},
 			{"SstpEnable", PsSstpEnable},
 			{"SstpGet", PsSstpGet},
 			{"ServerCertRegenerate", PsServerCertRegenerate},
@@ -21411,6 +21413,103 @@ UINT PsOpenVpnMakeConfig(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 	return ret;
 }
 
+// Enable / disable the OpenVPN compatible server function's obfuscation mode
+UINT PsOpenVpnObfuscationEnable(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
+{
+	LIST *o;
+	PS *ps = (PS *)param;
+	UINT ret = 0;
+	OPENVPN_SSTP_CONFIG t;
+	// Parameter list that can be specified
+	PARAM args[] =
+	{
+		// "name", prompt_proc, prompt_param, eval_proc, eval_param
+		{"[yes|no]", CmdPrompt, _UU("CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]"), CmdEvalNotEmpty, NULL},
+		{"MASK", CmdPrompt, _UU("CMD_OpenVpnObfuscationEnable_Prompt_MASK"), NULL, NULL},
+	};
+
+	o = ParseCommandList(c, cmd_name, str, args, sizeof(args) / sizeof(args[0]));
+	if (o == NULL)
+	{
+		return ERR_INVALID_PARAMETER;
+	}
+
+	Zero(&t, sizeof(t));
+
+	// RPC call
+	ret = ScGetOpenVpnSstpConfig(ps->Rpc, &t);
+
+	if (ret != ERR_NO_ERROR)
+	{
+		// An error has occured
+		CmdPrintError(c, ret);
+		FreeParamValueList(o);
+		return ret;
+	}
+
+	t.OpenVPNObfuscation = GetParamYes(o, "[yes|no]");
+	StrCpy(t.OpenVPNObfuscationMask, sizeof(t.OpenVPNObfuscationMask), GetParamStr(o, "MASK"));
+
+	// RPC call
+	ret = ScSetOpenVpnSstpConfig(ps->Rpc, &t);
+
+	if (ret != ERR_NO_ERROR)
+	{
+		// An error has occured
+		CmdPrintError(c, ret);
+		FreeParamValueList(o);
+		return ret;
+	}
+
+	FreeParamValueList(o);
+
+	return 0;
+}
+
+// Get the current settings for the OpenVPN compatible server function's obfuscation mode
+UINT PsOpenVpnObfuscationGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
+{
+	LIST *o;
+	PS *ps = (PS *)param;
+	UINT ret = 0;
+	OPENVPN_SSTP_CONFIG t;
+
+	o = ParseCommandList(c, cmd_name, str, NULL, 0);
+	if (o == NULL)
+	{
+		return ERR_INVALID_PARAMETER;
+	}
+
+	Zero(&t, sizeof(t));
+
+	// RPC call
+	ret = ScGetOpenVpnSstpConfig(ps->Rpc, &t);
+
+	if (ret != ERR_NO_ERROR)
+	{
+		// An error has occured
+		CmdPrintError(c, ret);
+		FreeParamValueList(o);
+		return ret;
+	}
+	else
+	{
+		wchar_t tmp[MAX_PATH];
+		CT *ct = CtNewStandard();
+
+		CtInsert(ct, _UU("CMD_OpenVpnObfuscationGet_PRINT_Enabled"), _UU(t.OpenVPNObfuscation ? "SEC_YES" : "SEC_NO"));
+
+		StrToUni(tmp, sizeof(tmp), t.OpenVPNObfuscationMask);
+		CtInsert(ct, _UU("CMD_OpenVpnObfuscationGet_PRINT_Mask"), tmp);
+
+		CtFree(ct, c);
+	}
+
+	FreeParamValueList(o);
+
+	return 0;
+}
+
 // Enable / disable the Microsoft SSTP VPN compatible server function
 UINT PsSstpEnable(CONSOLE *c, char *cmd_name, wchar_t *str, void *param)
 {

src/Cedar/Command.h

@@ -687,6 +687,8 @@ UINT PsEtherIpClientList(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsOpenVpnEnable(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsOpenVpnGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsOpenVpnMakeConfig(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
+UINT PsOpenVpnObfuscationEnable(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
+UINT PsOpenVpnObfuscationGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsSstpEnable(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsSstpGet(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);
 UINT PsServerCertRegenerate(CONSOLE *c, char *cmd_name, wchar_t *str, void *param);

src/Cedar/Proto_OpenVPN.c

@@ -306,9 +306,150 @@ UINT OvsDecrypt(CIPHER *cipher, MD *md, UCHAR *iv, UCHAR *dest, UCHAR *src, UINT
 	return 0;
 }
 
+// XOR the bytes with the specified string
+void OvsDataXorMask(void *data, const UINT data_size, const char *mask, const UINT mask_size)
+{
+	UINT i;
+	UCHAR *buf;
+	// Validate arguments
+	if (data == NULL || data_size == 0 || mask == NULL || mask_size == 0)
+	{
+		return;
+	}
+
+	for (i = 0, buf = data; i < data_size; i++, buf++)
+	{
+		*buf = *buf ^ mask[i % mask_size];
+	}
+}
+
+// XOR each byte with its position within the buffer
+void OvsDataXorPtrPos(void *data, const UINT size)
+{
+	UINT i;
+	UCHAR *buf;
+	// Validate arguments
+	if (data == NULL || size == 0)
+	{
+		return;
+	}
+
+	for (i = 0, buf = data; i < size; i++, buf++)
+	{
+		*buf = *buf ^ i + 1;
+	}
+}
+
+// Reverse bytes order if they're more than 2, keeping the first byte unchanged
+void OvsDataReverse(void *data, const UINT size)
+{
+	UINT i;
+	UCHAR tmp;
+	UCHAR *buf_start, *buf_end;
+	// Validate arguments
+	if (data == NULL || size < 3)
+	{
+		return;
+	}
+
+	for (i = 0, buf_start = (UCHAR *)data + 1, buf_end = (UCHAR *)data + (size - 1); i < (size - 1 ) / 2; i++, buf_start++, buf_end--)
+	{
+		tmp = *buf_start;
+		*buf_start = *buf_end;
+		*buf_end = tmp;
+	}
+}
+
+// Detects the method used to obfuscate the packet
+UINT OvsDetectObfuscation(void *data, UINT size, char *xormask)
+{
+	UINT ret;
+	void *tmp;
+	OPENVPN_PACKET *parsed_packet;
+	// Validate arguments
+	if (data == NULL || size == 0)
+	{
+		return INFINITE;
+	}
+
+	ret = INFINITE;
+	tmp = NULL;
+
+	// OPENVPN_SCRAMBLE_MODE_DISABLED
+	parsed_packet = OvsParsePacket(data, size);
+	if (parsed_packet != NULL)
+	{
+		ret = OPENVPN_SCRAMBLE_MODE_DISABLED;
+		goto final;
+	}
+
+	// OPENVPN_SCRAMBLE_MODE_XORMASK
+	tmp = Clone(data, size);
+
+	OvsDataXorMask(tmp, size, xormask, StrLen(xormask));
+
+	parsed_packet = OvsParsePacket(tmp, size);
+	if (parsed_packet != NULL)
+	{
+		ret = OPENVPN_SCRAMBLE_MODE_XORMASK;
+		goto final;
+	}
+
+	Free(tmp);
+
+	// OPENVPN_SCRAMBLE_MODE_XORPTRPOS
+	tmp = Clone(data, size);
+
+	OvsDataXorPtrPos(tmp, size);
+
+	parsed_packet = OvsParsePacket(tmp, size);
+	if (parsed_packet != NULL)
+	{
+		ret = OPENVPN_SCRAMBLE_MODE_XORPTRPOS;
+		goto final;
+	}
+
+	Free(tmp);
+
+	// OPENVPN_SCRAMBLE_MODE_REVERSE
+	tmp = Clone(data, size);
+
+	OvsDataReverse(tmp, size);
+
+	parsed_packet = OvsParsePacket(tmp, size);
+	if (parsed_packet != NULL)
+	{
+		ret = OPENVPN_SCRAMBLE_MODE_REVERSE;
+		goto final;
+	}
+
+	Free(tmp);
+
+	// OPENVPN_SCRAMBLE_MODE_OBFUSCATE
+	tmp = Clone(data, size);
+
+	OvsDataXorMask(tmp, size, xormask, StrLen(xormask));
+	OvsDataXorPtrPos(tmp, size);
+	OvsDataReverse(tmp, size);
+	OvsDataXorPtrPos(tmp, size);
+
+	parsed_packet = OvsParsePacket(tmp, size);
+	if (parsed_packet != NULL)
+	{
+		ret = OPENVPN_SCRAMBLE_MODE_OBFUSCATE;
+		goto final;
+	}
+
+final:
+	OvsFreePacket(parsed_packet);
+	Free(tmp);
+	return ret;
+}
+
 // Process the received packet
 void OvsProceccRecvPacket(OPENVPN_SERVER *s, UDPPACKET *p, UINT protocol)
 {
+	OPENVPN_CHANNEL *c;
 	OPENVPN_SESSION *se;
 	OPENVPN_PACKET *recv_packet;
 	// Validate arguments
@@ -317,7 +458,6 @@ void OvsProceccRecvPacket(OPENVPN_SERVER *s, UDPPACKET *p, UINT protocol)
 		return;
 	}
 
-
 	// Search for the session
 	se = OvsFindOrCreateSession(s, &p->DstIP, p->DestPort, &p->SrcIP, p->SrcPort, protocol);
 	if (se == NULL)
@@ -325,142 +465,179 @@ void OvsProceccRecvPacket(OPENVPN_SERVER *s, UDPPACKET *p, UINT protocol)
 		return;
 	}
 
-	// Parse the packet
+	// Detect obfuscation mode and save it for the next packets in the same session
-	recv_packet = OvsParsePacket(p->Data, p->Size);
+	if (se->ObfuscationMode == INFINITE)
-
-	if (recv_packet != NULL)
 	{
-		OPENVPN_CHANNEL *c = NULL;
+		se->ObfuscationMode = OvsDetectObfuscation(p->Data, p->Size, s->Cedar->OpenVPNObfuscationMask);
-		if (recv_packet->OpCode != OPENVPN_P_DATA_V1 && recv_packet->MySessionId != 0)
+		if (se->ObfuscationMode != INFINITE)
 		{
-			Debug("RECV PACKET: %u %I64u\n", recv_packet->KeyId, recv_packet->MySessionId);
+			Debug("OvsProceccRecvPacket(): detected packet obfuscation/scrambling mode: %u\n", se->ObfuscationMode);
-		}
-		if (recv_packet->OpCode != OPENVPN_P_DATA_V1)
-		{
-			Debug("   PKT %u %u\n", recv_packet->OpCode, recv_packet->KeyId);
-		}
-
-		if (recv_packet->OpCode != OPENVPN_P_DATA_V1)
-		{
-			// Control packet
-			if (recv_packet->OpCode == OPENVPN_P_CONTROL_HARD_RESET_CLIENT_V2 ||
-				recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1)
-			{
-				// Connection request packet
-				if (se->Channels[recv_packet->KeyId] != NULL)
-				{
-					// Release when there is a channel data already
-					OvsFreeChannel(se->Channels[recv_packet->KeyId]);
-					se->Channels[recv_packet->KeyId] = NULL;
-				}
-
-				// Create a new channel
-				c = OvsNewChannel(se, recv_packet->KeyId);
-				if (se->ClientSessionId == 0)
-				{
-					se->ClientSessionId = recv_packet->MySessionId;
-				}
-				se->Channels[recv_packet->KeyId] = c;
-				Debug("OpenVPN New Channel :%u\n", recv_packet->KeyId);
-				OvsLog(s, se, c, "LO_NEW_CHANNEL");
-			}
-/*			else if (recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1)
-			{
-				// Response to soft reset request packet
-				OPENVPN_PACKET *p;
-
-				p = OvsNewControlPacket(OPENVPN_P_CONTROL_SOFT_RESET_V1, recv_packet->KeyId, se->ServerSessionId,
-					0, NULL, 0, 0, 0, NULL);
-
-				OvsSendPacketNow(s, se, p);
-
-				OvsFreePacket(p);
-			}*/
-			else
-			{
-				// Packet other than the connection request
-				if (se->Channels[recv_packet->KeyId] != NULL)
-				{
-					c = se->Channels[recv_packet->KeyId];
-				}
-			}
-
-			if (c != NULL)
-			{
-				// Delete the send packet list by looking the packet ID in the ACK list of arrived packet
-				OvsDeleteFromSendingControlPacketList(c, recv_packet->NumAck, recv_packet->AckPacketId);
-
-				if (recv_packet->OpCode != OPENVPN_P_ACK_V1)
-				{
-					// Add the Packet ID of arrived packet to the list
-					InsertIntDistinct(c->AckReplyList, recv_packet->PacketId);
-					Debug("Recv Packet ID (c=%u): %u\n", c->KeyId, recv_packet->PacketId);
-
-					if ((recv_packet->PacketId > c->MaxRecvPacketId)
-						|| (recv_packet->OpCode == OPENVPN_P_CONTROL_HARD_RESET_CLIENT_V2)
-						|| (recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1))
-					{
-						c->MaxRecvPacketId = recv_packet->PacketId;
-
-						// Process the received control packet
-						OvsProcessRecvControlPacket(s, se, c, recv_packet);
-					}
-				}
-			}
 		}
 		else
 		{
-			// Data packet
+			Debug("OvsProceccRecvPacket(): failed to detect packet obfuscation/scrambling mode!\n");
+			return;
+		}
+	}
+
+	// Handle scrambled packet
+	switch (se->ObfuscationMode)
+	{
+	case OPENVPN_SCRAMBLE_MODE_DISABLED:
+		break;
+	case OPENVPN_SCRAMBLE_MODE_XORMASK:
+		OvsDataXorMask(p->Data, p->Size, s->Cedar->OpenVPNObfuscationMask, StrLen(s->Cedar->OpenVPNObfuscationMask));
+		break;
+	case OPENVPN_SCRAMBLE_MODE_XORPTRPOS:
+		OvsDataXorPtrPos(p->Data, p->Size);
+		break;
+	case OPENVPN_SCRAMBLE_MODE_REVERSE:
+		OvsDataReverse(p->Data, p->Size);
+		break;
+	case OPENVPN_SCRAMBLE_MODE_OBFUSCATE:
+		OvsDataXorMask(p->Data, p->Size, s->Cedar->OpenVPNObfuscationMask, StrLen(s->Cedar->OpenVPNObfuscationMask));
+		OvsDataXorPtrPos(p->Data, p->Size);
+		OvsDataReverse(p->Data, p->Size);
+		OvsDataXorPtrPos(p->Data, p->Size);
+	}
+
+	// Parse the packet
+	recv_packet = OvsParsePacket(p->Data, p->Size);
+	if (recv_packet == NULL)
+	{
+		Debug("OvsProceccRecvPacket(): OvsParsePacket() returned NULL!\n");
+		return;
+	}
+
+	if (recv_packet->OpCode != OPENVPN_P_DATA_V1 && recv_packet->MySessionId != 0)
+	{
+		Debug("RECV PACKET: %u %I64u\n", recv_packet->KeyId, recv_packet->MySessionId);
+	}
+	if (recv_packet->OpCode != OPENVPN_P_DATA_V1)
+	{
+		Debug("   PKT %u %u\n", recv_packet->OpCode, recv_packet->KeyId);
+	}
+
+	if (recv_packet->OpCode != OPENVPN_P_DATA_V1)
+	{
+		// Control packet
+		if (recv_packet->OpCode == OPENVPN_P_CONTROL_HARD_RESET_CLIENT_V2 ||
+			recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1)
+		{
+			// Connection request packet
 			if (se->Channels[recv_packet->KeyId] != NULL)
 			{
-				OPENVPN_CHANNEL *c = se->Channels[recv_packet->KeyId];
+				// Release when there is a channel data already
-				if (c->Status == OPENVPN_CHANNEL_STATUS_ESTABLISHED)
+				OvsFreeChannel(se->Channels[recv_packet->KeyId]);
+				se->Channels[recv_packet->KeyId] = NULL;
+			}
+
+			// Create a new channel
+			c = OvsNewChannel(se, recv_packet->KeyId);
+			if (se->ClientSessionId == 0)
+			{
+				se->ClientSessionId = recv_packet->MySessionId;
+			}
+			se->Channels[recv_packet->KeyId] = c;
+			Debug("OpenVPN New Channel :%u\n", recv_packet->KeyId);
+			OvsLog(s, se, c, "LO_NEW_CHANNEL");
+		}
+/*		else if (recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1)
+		{
+			// Response to soft reset request packet
+			OPENVPN_PACKET *p;
+
+			p = OvsNewControlPacket(OPENVPN_P_CONTROL_SOFT_RESET_V1, recv_packet->KeyId, se->ServerSessionId,
+				0, NULL, 0, 0, 0, NULL);
+
+			OvsSendPacketNow(s, se, p);
+
+			OvsFreePacket(p);
+		}*/
+		else
+		{
+			// Packet other than the connection request
+			if (se->Channels[recv_packet->KeyId] != NULL)
+			{
+				c = se->Channels[recv_packet->KeyId];
+			}
+		}
+
+		if (c != NULL)
+		{
+			// Delete the send packet list by looking the packet ID in the ACK list of arrived packet
+			OvsDeleteFromSendingControlPacketList(c, recv_packet->NumAck, recv_packet->AckPacketId);
+
+			if (recv_packet->OpCode != OPENVPN_P_ACK_V1)
+			{
+				// Add the Packet ID of arrived packet to the list
+				InsertIntDistinct(c->AckReplyList, recv_packet->PacketId);
+				Debug("Recv Packet ID (c=%u): %u\n", c->KeyId, recv_packet->PacketId);
+
+				if ((recv_packet->PacketId > c->MaxRecvPacketId)
+					|| (recv_packet->OpCode == OPENVPN_P_CONTROL_HARD_RESET_CLIENT_V2)
+					|| (recv_packet->OpCode == OPENVPN_P_CONTROL_SOFT_RESET_V1))
 				{
-					UINT size;
+					c->MaxRecvPacketId = recv_packet->PacketId;
-					UCHAR *data = s->TmpBuf;
+
-					if (c->CipherDecrypt->IsAeadCipher)
+					// Process the received control packet
+					OvsProcessRecvControlPacket(s, se, c, recv_packet);
+				}
+			}
+		}
+	}
+	else
+	{
+		// Data packet
+		if (se->Channels[recv_packet->KeyId] != NULL)
+		{
+			OPENVPN_CHANNEL *c = se->Channels[recv_packet->KeyId];
+			if (c->Status == OPENVPN_CHANNEL_STATUS_ESTABLISHED)
+			{
+				UINT size;
+				UCHAR *data = s->TmpBuf;
+				if (c->CipherDecrypt->IsAeadCipher)
+				{
+					// Update variable part (packet ID) of IV
+					Copy(c->IvRecv, recv_packet->Data, sizeof(recv_packet->PacketId));
+
+					// Decrypt
+					size = OvsDecrypt(c->CipherDecrypt, NULL, c->IvRecv, data, recv_packet->Data + sizeof(UINT), recv_packet->DataSize - sizeof(UINT));
+				}
+				else
+				{
+					// Decrypt
+					size = OvsDecrypt(c->CipherDecrypt, c->MdRecv, c->IvRecv, data, recv_packet->Data, recv_packet->DataSize);
+
+					// Seek buffer after the packet ID
+					data += sizeof(UINT);
+					size -= sizeof(UINT);
+				}
+
+				// Update of last communication time
+				se->LastCommTick = s->Now;
+
+				if (size < sizeof(ping_signature) || Cmp(data, ping_signature, sizeof(ping_signature)) != 0)
+				{
+					// Receive a packet!
+					if (se->Ipc != NULL)
 					{
-						// Update variable part (packet ID) of IV
+						switch (se->Mode)
-						Copy(c->IvRecv, recv_packet->Data, sizeof(recv_packet->PacketId));
-
-						// Decrypt
-						size = OvsDecrypt(c->CipherDecrypt, NULL, c->IvRecv, data, recv_packet->Data + sizeof(UINT), recv_packet->DataSize - sizeof(UINT));
-					}
-					else
-					{
-						// Decrypt
-						size = OvsDecrypt(c->CipherDecrypt, c->MdRecv, c->IvRecv, data, recv_packet->Data, recv_packet->DataSize);
-
-						// Seek buffer after the packet ID
-						data += sizeof(UINT);
-						size -= sizeof(UINT);
-					}
-
-					// Update of last communication time
-					se->LastCommTick = s->Now;
-
-					if (size < sizeof(ping_signature) || Cmp(data, ping_signature, sizeof(ping_signature)) != 0)
-					{
-						// Receive a packet!
-						if (se->Ipc != NULL)
 						{
-							switch (se->Mode)
+						case OPENVPN_MODE_L2:	// Send an Ethernet packet to a session
-							{
+							IPCSendL2(se->Ipc, data, size);
-							case OPENVPN_MODE_L2:	// Send an Ethernet packet to a session
+							break;
-								IPCSendL2(se->Ipc, data, size);
+						case OPENVPN_MODE_L3:	// Send an IPv4 packet to a session
-								break;
+							IPCSendIPv4(se->Ipc, data, size);
-							case OPENVPN_MODE_L3:	// Send an IPv4 packet to a session
+							break;
-								IPCSendIPv4(se->Ipc, data, size);
-								break;
-							}
 						}
 					}
 				}
 			}
 		}
-
-		OvsFreePacket(recv_packet);
 	}
+
+	OvsFreePacket(recv_packet);
 }
 
 // Remove a packet which the opponent has received from the transmission list
@@ -1725,7 +1902,6 @@ OPENVPN_PACKET *OvsParsePacket(UCHAR *data, UINT size)
 	return ret;
 
 LABEL_ERROR:
-	Debug("OvsParsePacket Error.\n");
 	OvsFreePacket(ret);
 	return NULL;
 }
@@ -1830,6 +2006,8 @@ OPENVPN_SESSION *OvsNewSession(OPENVPN_SERVER *s, IP *server_ip, UINT server_por
 	Copy(&se->ServerIp, server_ip, sizeof(IP));
 	se->ServerPort = server_port;
 
+	se->ObfuscationMode = s->Cedar->OpenVPNObfuscation ? INFINITE : OPENVPN_SCRAMBLE_MODE_DISABLED;
+
 	se->LastCommTick = s->Now;
 
 	se->Protocol = protocol;
@@ -2508,6 +2686,27 @@ void OvsSendPacketRawNow(OPENVPN_SERVER *s, OPENVPN_SESSION *se, void *data, UIN
 		return;
 	}
 
+	// Scramble the packet
+	switch (se->ObfuscationMode)
+	{
+	case OPENVPN_SCRAMBLE_MODE_DISABLED:
+		break;
+	case OPENVPN_SCRAMBLE_MODE_XORMASK:
+		OvsDataXorMask(data, size, s->Cedar->OpenVPNObfuscationMask, StrLen(s->Cedar->OpenVPNObfuscationMask));
+		break;
+	case OPENVPN_SCRAMBLE_MODE_XORPTRPOS:
+		OvsDataXorPtrPos(data, size);
+		break;
+	case OPENVPN_SCRAMBLE_MODE_REVERSE:
+		OvsDataReverse(data, size);
+		break;
+	case OPENVPN_SCRAMBLE_MODE_OBFUSCATE:
+		OvsDataXorPtrPos(data, size);
+		OvsDataReverse(data, size);
+		OvsDataXorPtrPos(data, size);
+		OvsDataXorMask(data, size, s->Cedar->OpenVPNObfuscationMask, StrLen(s->Cedar->OpenVPNObfuscationMask));
+	}
+
 	u = NewUdpPacket(&se->ServerIp, se->ServerPort, &se->ClientIp, se->ClientPort,
 		data, size);
 

src/Cedar/Proto_OpenVPN.h

@@ -185,6 +185,12 @@
 #define	OPENVPN_MODE_L2							1		// TAP (Ethernet)
 #define	OPENVPN_MODE_L3							2		// TUN (IP)
 
+// Scramble mode
+#define	OPENVPN_SCRAMBLE_MODE_DISABLED			0		// No scramble
+#define	OPENVPN_SCRAMBLE_MODE_XORMASK			1		// XOR the bytes with the specified string
+#define	OPENVPN_SCRAMBLE_MODE_XORPTRPOS			2		// XOR each byte with its position in the buffer
+#define	OPENVPN_SCRAMBLE_MODE_REVERSE			3		// Reverses bytes order, keeping the first byte unchanged
+#define	OPENVPN_SCRAMBLE_MODE_OBFUSCATE			4		// Performs the above steps using the specified string for xormask
 
 //// Type
 
@@ -271,6 +277,7 @@ struct OPENVPN_SESSION
 	OPENVPN_CHANNEL *Channels[OPENVPN_NUM_CHANNELS];	// Channels (up to 8)
 	UINT LastCreatedChannelIndex;						// Channel number that is created in the last
 	UINT Mode;											// Mode (L3 or L2)
+	UINT ObfuscationMode;								// Packet obfuscation/scrambling mode
 	UINT LinkMtu;										// link-mtu
 	UINT TunMtu;										// tun-mtu
 	IPC_ASYNC *IpcAsync;								// Asynchronous IPC connection

src/Cedar/Server.c

@@ -154,6 +154,9 @@ void SiSetOpenVPNAndSSTPConfig(SERVER *s, OPENVPN_SSTP_CONFIG *c)
 		NormalizeIntListStr(s->OpenVpnServerUdpPorts, sizeof(s->OpenVpnServerUdpPorts),
 			c->OpenVPNPortList, true, ", ");
 
+		s->Cedar->OpenVPNObfuscation = c->OpenVPNObfuscation;
+		StrCpy(s->Cedar->OpenVPNObfuscationMask, sizeof(s->Cedar->OpenVPNObfuscationMask), c->OpenVPNObfuscationMask);
+
 		// Apply the OpenVPN configuration
 		if (s->OpenVpnServerUdp != NULL)
 		{
@@ -194,6 +197,9 @@ void SiGetOpenVPNAndSSTPConfig(SERVER *s, OPENVPN_SSTP_CONFIG *c)
 		}
 
 		StrCpy(c->OpenVPNPortList, sizeof(c->OpenVPNPortList), s->OpenVpnServerUdpPorts);
+
+		c->OpenVPNObfuscation = s->Cedar->OpenVPNObfuscation;
+		StrCpy(c->OpenVPNObfuscationMask, sizeof(c->OpenVPNObfuscationMask), s->Cedar->OpenVPNObfuscationMask);
 	}
 	Unlock(s->OpenVpnSstpConfigLock);
 }
@@ -2569,6 +2575,8 @@ void SiLoadInitialConfiguration(SERVER *s)
 			ToStr(c.OpenVPNPortList, OPENVPN_UDP_PORT);
 		}
 
+		c.OpenVPNObfuscation = false;
+
 		SiSetOpenVPNAndSSTPConfig(s, &c);
 
 		{
@@ -6000,6 +6008,16 @@ void SiLoadServerCfg(SERVER *s, FOLDER *f)
 		config.EnableSSTP = !s->DisableSSTPServer;
 		StrCpy(config.OpenVPNPortList, sizeof(config.OpenVPNPortList), tmp);
 
+		config.OpenVPNObfuscation = CfgGetBool(f, "OpenVPNObfuscation");
+
+		if (CfgGetStr(f, "OpenVPNObfuscationMask", tmp, sizeof(tmp)))
+		{
+			if (IsEmptyStr(tmp) == false)
+			{
+				StrCpy(config.OpenVPNObfuscationMask, sizeof(config.OpenVPNObfuscationMask), tmp);
+			}
+		}
+
 		SiSetOpenVPNAndSSTPConfig(s, &config);
 
 		if (s->ServerType == SERVER_TYPE_FARM_MEMBER)
@@ -6271,6 +6289,9 @@ void SiWriteServerCfg(FOLDER *f, SERVER *s)
 			SiGetOpenVPNAndSSTPConfig(s, &config);
 
 			CfgAddStr(f, "OpenVPN_UdpPortList", config.OpenVPNPortList);
+
+			CfgAddBool(f, "OpenVPNObfuscation", config.OpenVPNObfuscation);
+			CfgAddStr(f, "OpenVPNObfuscationMask", config.OpenVPNObfuscationMask);
 		}
 
 		// WebTimePage

src/Cedar/Server.h

@@ -253,6 +253,8 @@ struct OPENVPN_SSTP_CONFIG
 {
 	bool EnableOpenVPN;						// OpenVPN is enabled
 	char OpenVPNPortList[MAX_SIZE];			// OpenVPN UDP port number list
+	bool OpenVPNObfuscation;				// OpenVPN: Obfuscation mode
+	char OpenVPNObfuscationMask[MAX_SIZE];	// OpenVPN: String (mask) for XOR obfuscation
 	bool EnableSSTP;						// SSTP is enabled
 };
 

src/bin/hamcore/strtable_cn.stb

@@ -6280,6 +6280,24 @@ CMD_OpenVpnMakeConfig_OK				样本设置文件被保存为 "%s"。您可以解
 CMD_OpenVpnMakeConfig_ERROR				本样本设置文件不能保存为 "%s"。该文件名无效。\n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable					Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help				This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args				OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no]			Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK				Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]	Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK		XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet				Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help			Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args			OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled	OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask	XOR mask
+
+
 # SstpEnable 命令
 CMD_SstpEnable						启用/禁用 Microsoft SSTP VPN 克隆服务器功能
 CMD_SstpEnable_Help					本 VPN Server 拥有植入在微软 Windows Server 2008 / 2012 中的 MS-SSTP VPN Server 的克隆功能。Windows Vista / 7 / 8 / RT / 10 中的标准 MS-SSTP 用户端可以连接本 VPN Server。\n\n[注意]\n在 VPN Server 上的 SSL 证书 CN 值必须要和指定给客户端的主机名吻合。并且，该证书必须在 SSTP VPN Client 的信任列表中。详情请参见微软相关文件。\n您可以用用 ServerCertRegenerate 命令来取代当前 VPN Server 的证书，形成一个新的，有 CN 值字段的自我认证证书。这样的话，您需要在 SSTP VPN Client 注册这样一个新的自我认证证书作为一个可信任根证书。如果您的确想做这件复杂的事，请考虑购买一个商业权威机构的 SSL 证书，如 VeriSign 或者 GlobalSign。\n\n指定用户名连接到虚拟 HUB 的的方式，使用本克隆服务器功能来为默认虚拟 HUB 的选择规则都与 IPsec 服务器功能相同。详情，请参见 IPsecEnable 命令的帮助。\n\n要执行此命令，您必须具有 VPN Server 管理员权限。\n该命令在 VPN Bridge 上不能运行。\n以集群成员运行的 VPN Server 的虚拟 HUB 不能执行此命令。

src/bin/hamcore/strtable_en.stb

@@ -6264,6 +6264,24 @@ CMD_OpenVpnMakeConfig_OK			The sample setting file was saved as "%s". You can un
 CMD_OpenVpnMakeConfig_ERROR			The sample setting files were unable to be saved as "%s". The filename might be invalid.\n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable					Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help				This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args				OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no]			Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK				Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]	Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK		XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet				Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help			Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args			OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled	OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask	XOR mask
+
+
 # SstpEnable command
 CMD_SstpEnable			Enable / Disable Microsoft SSTP VPN Clone Server Function
 CMD_SstpEnable_Help		This VPN Server has the clone functions of MS-SSTP VPN Server which is on Windows Server 2008 / 2012 by Microsoft Corporation. Standard MS-SSTP Clients in Windows Vista / 7 / 8 / RT / 10 can connect to this VPN Server.\n\n[Caution]\nThe value of CN (Common Name) on the SSL certificate of VPN Server must match to the hostname specified on the client, and that certificate must be in the trusted list on the SSTP VPN client. For details refer the Microsoft's documents.\nYou can use the ServerCertRegenerate command to replace the current certificate on the VPN Server to a new self-signed certificate which has the CN (Common Name) value in the fields. In that case, you have to register such a new self-signed certificate on the SSTP VPN Client as a trusted root certificate. If you do not want to do such a bother tasks, please consider to purchase a SSL certificate provided by commercial authority such as VeriSign or GlobalSign.\n\nThe manner to specify a username to connect to the Virtual Hub, and the selection rule of default Hub by using this clone server functions are same to the IPsec Server functions. For details, please see the help of the IPsecEnable command.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.

src/bin/hamcore/strtable_ja.stb

@@ -6271,6 +6271,24 @@ CMD_OpenVpnMakeConfig_OK			サンプル設定ファイルを "%s" ファイル
 CMD_OpenVpnMakeConfig_ERROR			サンプル設定ファイルを "%s" ファイルに保存できませんでした。ファイル名が正しくない可能性があります。\n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable					Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help				This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args				OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no]			Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK				Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]	Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK		XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet				Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help			Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args			OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled	OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask	XOR mask
+
+
 # SstpEnable コマンド
 CMD_SstpEnable			Microsoft SSTP VPN 互換サーバー機能を有効化 / 無効化
 CMD_SstpEnable_Help		SoftEther VPN Server には Microsoft 社の Windows Server 2008 / 2012 製品に搭載されている MS-SSTP VPN サーバー機能と互換性がある機能が搭載されています。Microsoft SSTP VPN 互換サーバー機能を有効にすると、Windows Vista / 7 / 8 / RT / 10 に標準搭載の MS-SSTP クライアントからこの VPN Server に接続できるようになります。\n\n[ご注意]\nVPN Server の SSL 証明書の CN の値がクライアント側で指定するホスト名と一致し、かつその証明書が信頼されている必要があります。詳しくは Microsoft 社のドキュメントを参照してください。\n指定された CN の値を持つ新しい SSL 証明書 (自己署名証明書) を生成して VPN Server の現在の証明書と置換するためには、ServerCertRegenerate コマンドを使用してください。この場合は、当該証明書を SSTP VPN クライアントのコンピュータの信頼されるルート証明書として登録する必要があります。このような手間をかけたくない場合は、代わりに VeriSign や GlobalSign 社などの市販の証明書業者の SSL 証明書の取得を検討してください。\n\nMicrosoft SSTP VPN 互換サーバー機能で仮想 HUB に接続する場合のユーザー名の指定方法、およびデフォルト仮想 HUB の選択規則は、IPsec サーバー機能と同様です。詳しくは IPsecEnable コマンドのヘルプを参照してください。\n\nこのコマンドを実行するには、VPN Server の管理者権限が必要です。\nこのコマンドは、VPN Bridge では実行できません。\nこのコマンドは、クラスタとして動作している VPN Server の仮想 HUB では実行できません。

src/bin/hamcore/strtable_ko.stb

@@ -6246,6 +6246,23 @@ CMD_OpenVpnMakeConfig_OK 예제 구성 파일 "%s"파일에 저장했습니다.
 CMD_OpenVpnMakeConfig_ERROR 예제 구성 파일 "%s"파일에 저장할 수 없습니다. 파일 이름이 잘못되었을 수 있습니다. \n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no] Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no] Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask XOR mask
+
 # SstpEnable 명령
 CMD_SstpEnable Microsoft SSTP VPN 호환 서버 기능을 활성화/비활성화
 CMD_SstpEnable_Help SoftEther VPN Server는 Microsoft 사의 Windows Server 2008/2012 제품에 탑재 된 MS-SSTP VPN 서버 기능과 호환 기능이 탑재되어 있습니다. Microsoft SSTP VPN 호환 서버 기능을 활성화하면 Windows Vista/7/8/RT에 내장 된 MS-SSTP 클라이언트에서이 VPN Server에 연결할 수 있도록합니다. \n \n [주의] \nVPN Server의 SSL 인증서의 CN 값이 클라이언트 측에서 지정하는 호스트 이름과 일치하며 그 인증서를 신뢰할 수 있어야합니다. 자세한 내용은 Microsoft 문서를 참조하십시오. \n 지정된 CN 값을 가지는 새로운 SSL 인증서 (자체 서명 인증서)를 생성하여 VPN Server의 현재 인증서로 대체하기 위해서는 ServerCertRegenerate 명령을 사용하십시오. 이 경우 해당 인증서를 SSTP VPN 클라이언트 컴퓨터의 신뢰할 수있는 루트 인증서로 등록해야합니다. 이러한 번거 로움 않으려면 대신 VeriSign이나 GlobalSign 사 등의 상용 인증서 공급자의 SSL 인증서 취득을 검토하십시오. \n \nMicrosoft SSTP VPN 호환 서버 기능으로 가상 HUB에 연결하는 경우 사용자 이름 지정 방법 및 기본 가상 HUB 선택 규칙은 IPsec 서버 기능과 유사합니다. 자세한 내용은 IPsecEnable 명령의 도움말을 참조하십시오. \n \n이 명령을 실행하려면 VPN Server 관리자 권한이 있어야합니다. \n이 명령은 VPN Bridge에서는 실행되지 않습니다. \n이 명령은 클러스터로 작동하는 VPN Server의 가상 HUB에서는 실행되지 않습니다.

src/bin/hamcore/strtable_ru.stb

@@ -6248,6 +6248,24 @@ CMD_OpenVpnMakeConfig_OK			The sample setting file was saved as "%s". You can un
 CMD_OpenVpnMakeConfig_ERROR			The sample setting files were unable to be saved as "%s". The filename might be invalid.\n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable					Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help				This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args				OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no]			Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK				Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]	Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK		XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet				Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help			Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args			OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled	OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask	XOR mask
+
+
 # SstpEnable command
 CMD_SstpEnable			Enable / Disable Microsoft SSTP VPN Clone Server Function
 CMD_SstpEnable_Help		This VPN Server has the clone functions of MS-SSTP VPN Server which is on Windows Server 2008 / 2012 by Microsoft Corporation. Standard MS-SSTP Clients in Windows Vista / 7 / 8 / RT / 10 can connect to this VPN Server.\n\n[Caution]\nThe value of CN (Common Name) on the SSL certificate of VPN Server must match to the hostname specified on the client, and that certificate must be in the trusted list on the SSTP VPN client. For details refer the Microsoft's documents.\nYou can use the ServerCertRegenerate command to replace the current certificate on the VPN Server to a new self-signed certificate which has the CN (Common Name) value in the fields. In that case, you have to register such a new self-signed certificate on the SSTP VPN Client as a trusted root certificate. If you do not want to do such a bother tasks, please consider to purchase a SSL certificate provided by commercial authority such as VeriSign or GlobalSign.\n\nThe manner to specify a username to connect to the Virtual Hub, and the selection rule of default Hub by using this clone server functions are same to the IPsec Server functions. For details, please see the help of the IPsecEnable command.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.

src/bin/hamcore/strtable_tw.stb

@@ -6281,6 +6281,24 @@ CMD_OpenVpnMakeConfig_OK				樣本設置檔案被保存為 "%s"。您可以解
 CMD_OpenVpnMakeConfig_ERROR				本樣本設置檔案不能保存為 "%s"。該檔案名無效。\n
 
 
+# OpenVpnObfuscationEnable
+CMD_OpenVpnObfuscationEnable					Enable / Disable the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationEnable_Help				This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.\nThe same XOR mask have to be applied to the client, otherwise it will not be able to connect with certain obfuscation methods!\nBeware that you need a special OpenVPN client with the "XOR patch" applied in order to use this function, because it has never been merged in the official OpenVPN repository.\n\nTo execute this command, you must have VPN Server administrator privileges. \nThis command cannot be run on VPN Bridge.\nYou cannot execute this command for Virtual Hubs of VPN Servers operating as a cluster.
+CMD_OpenVpnObfuscationEnable_Args				OpenVpnObfuscationEnable [yes|no] [/MASK:mask]
+CMD_OpenVpnObfuscationEnable_[yes|no]			Specify "yes" to enable the OpenVPN obfuscation function. Specify "no" to disable it.
+CMD_OpenVpnObfuscationEnable_MASK				Mask used to XOR the bytes in the packet (used for certain obfuscation modes).
+CMD_OpenVpnObfuscationEnable_Prompt_[yes|no]	Enable OpenVPN packet obfuscation (yes / no): 
+CMD_OpenVpnObfuscationEnable_Prompt_MASK		XOR mask: 
+
+
+# OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet				Get the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Help			Get and show the current settings of the OpenVPN clone server function's obfuscation mode
+CMD_OpenVpnObfuscationGet_Args			OpenVpnObfuscationGet
+CMD_OpenVpnObfuscationGet_PRINT_Enabled	OpenVPN obfuscation enabled
+CMD_OpenVpnObfuscationGet_PRINT_Mask	XOR mask
+
+
 # SstpEnable 命令
 CMD_SstpEnable						啟用/禁用 Microsoft SSTP VPN 克隆伺服器功能
 CMD_SstpEnable_Help					本 VPN Server 擁有植入在微軟 Windows Server 2008 / 2012 中的 MS-SSTP VPN Server 的克隆功能。Windows Vista / 7 / 8 / RT / 10 中的標準 MS-SSTP 用戶端可以連接本 VPN Server。\n\n[注意]\n在 VPN Server 上的 SSL 證書 CN 值必須要和指定給用戶端的主機名稱吻合。並且，該證書必須在 SSTP VPN Client 的信任清單中。詳情請參見微軟相關檔。\n您可以用用 ServerCertRegenerate 命令來取代當前 VPN Server 的證書，形成一個新的，有 CN 值欄位的自我認證證書。這樣的話，您需要在 SSTP VPN Client 註冊這樣一個新的自我認證證書作為一個可信任根證書。如果您的確想做這件複雜的事，請考慮購買一個商業權威機構的 SSL 證書，如 VeriSign 或者 GlobalSign。\n\n指定用戶名連接到虛擬 HUB 的的方式，使用本克隆伺服器功能來為預設虛擬 HUB 的選擇規則都與 IPsec 伺服器功能相同。詳情，請參見 IPsecEnable 命令的幫助。\n\n要執行此命令，您必須具有 VPN Server 管理員許可權。\n該命令在 VPN Bridge 上不能運行。\n以集群成員運行的 VPN Server 的虛擬 HUB 不能執行此命令。