From 3d7524cac91b4b33d07a5664923af8987ecdfdd0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Moreau?= <marcandre.moreau@gmail.com>
Date: Tue, 3 Jun 2014 13:00:03 -0400
Subject: [PATCH] channels/drdynvc: add state machine, add workaround for
 missing capabilities pdu

---
 channels/drdynvc/client/drdynvc_main.c | 57 +++++++++++++++++++-------
 channels/drdynvc/client/drdynvc_main.h | 12 ++++++
 2 files changed, 55 insertions(+), 14 deletions(-)

diff --git a/channels/drdynvc/client/drdynvc_main.c b/channels/drdynvc/client/drdynvc_main.c
index b1a6ed588..0b83753b0 100644
--- a/channels/drdynvc/client/drdynvc_main.c
+++ b/channels/drdynvc/client/drdynvc_main.c
@@ -153,12 +153,32 @@ int drdynvc_push_event(drdynvcPlugin* drdynvc, wMessage* event)
 	return 0;
 }
 
+static int drdynvc_send_capability_response(drdynvcPlugin* drdynvc)
+{
+	int status;
+	wStream* data_out;
+
+	data_out = Stream_New(NULL, 4);
+	Stream_Write_UINT16(data_out, 0x0050); /* Cmd+Sp+cbChId+Pad. Note: MSTSC sends 0x005c */
+	Stream_Write_UINT16(data_out, drdynvc->version);
+
+	status = svc_plugin_send((rdpSvcPlugin*) drdynvc, data_out);
+
+	if (status != CHANNEL_RC_OK)
+	{
+		DEBUG_WARN("VirtualChannelWrite failed %d", status);
+		return 1;
+	}
+
+	return status;
+}
+
 static int drdynvc_process_capability_request(drdynvcPlugin* drdynvc, int Sp, int cbChId, wStream* s)
 {
-	wStream* data_out;
-	int error;
+	int status;
 
 	DEBUG_DVC("Sp=%d cbChId=%d", Sp, cbChId);
+
 	Stream_Seek(s, 1); /* pad */
 	Stream_Read_UINT16(s, drdynvc->version);
 
@@ -173,18 +193,11 @@ static int drdynvc_process_capability_request(drdynvcPlugin* drdynvc, int Sp, in
 		Stream_Read_UINT16(s, drdynvc->PriorityCharge3);
 	}
 
-	data_out = Stream_New(NULL, 4);
-	Stream_Write_UINT16(data_out, 0x0050); /* Cmd+Sp+cbChId+Pad. Note: MSTSC sends 0x005c */
-	Stream_Write_UINT16(data_out, drdynvc->version);
-	error = svc_plugin_send((rdpSvcPlugin*) drdynvc, data_out);
+	status = drdynvc_send_capability_response(drdynvc);
 
-	if (error != CHANNEL_RC_OK)
-	{
-		DEBUG_WARN("VirtualChannelWrite failed %d", error);
-		return 1;
-	}
+	drdynvc->channel_error = status;
 
-	drdynvc->channel_error = error;
+	drdynvc->state = DRDYNVC_STATE_READY;
 
 	return 0;
 }
@@ -219,6 +232,19 @@ static int drdynvc_process_create_request(drdynvcPlugin* drdynvc, int Sp, int cb
 	wStream* data_out;
 	int channel_status;
 
+	if (drdynvc->state == DRDYNVC_STATE_CAPABILITIES)
+	{
+		/**
+		 * For some reason the server does not always send the
+		 * capabilities pdu as it should. When this happens,
+		 * send a capabilities response.
+		 */
+
+		drdynvc->version = 3;
+		drdynvc_send_capability_response(drdynvc);
+		drdynvc->state = DRDYNVC_STATE_READY;
+	}
+
 	ChannelId = drdynvc_read_variable_uint(s, cbChId);
 	pos = Stream_GetPosition(s);
 	DEBUG_DVC("ChannelId=%d ChannelName=%s", ChannelId, Stream_Pointer(s));
@@ -381,6 +407,8 @@ static void drdynvc_process_connect(rdpSvcPlugin* plugin)
 	}
 
 	dvcman_init(drdynvc->channel_mgr);
+
+	drdynvc->state = DRDYNVC_STATE_CAPABILITIES;
 }
 
 static void drdynvc_process_event(rdpSvcPlugin* plugin, wMessage* event)
@@ -419,8 +447,7 @@ BOOL VCAPITYPE VirtualChannelEntry(PCHANNEL_ENTRY_POINTS pEntryPoints)
 	DrdynvcClientContext* context;
 	CHANNEL_ENTRY_POINTS_FREERDP* pEntryPointsEx;
 
-	_p = (drdynvcPlugin*) malloc(sizeof(drdynvcPlugin));
-	ZeroMemory(_p, sizeof(drdynvcPlugin));
+	_p = (drdynvcPlugin*) calloc(1, sizeof(drdynvcPlugin));
 
 	_p->plugin.channel_def.options =
 		CHANNEL_OPTION_INITIALIZED |
@@ -429,6 +456,8 @@ BOOL VCAPITYPE VirtualChannelEntry(PCHANNEL_ENTRY_POINTS pEntryPoints)
 
 	strcpy(_p->plugin.channel_def.name, "drdynvc");
 
+	_p->state = DRDYNVC_STATE_INITIAL;
+
 	_p->plugin.connect_callback = drdynvc_process_connect;
 	_p->plugin.receive_callback = drdynvc_process_receive;
 	_p->plugin.event_callback = drdynvc_process_event;
diff --git a/channels/drdynvc/client/drdynvc_main.h b/channels/drdynvc/client/drdynvc_main.h
index 369084a19..4eda9d8f5 100644
--- a/channels/drdynvc/client/drdynvc_main.h
+++ b/channels/drdynvc/client/drdynvc_main.h
@@ -26,6 +26,17 @@
 #include <freerdp/client/drdynvc.h>
 #include <freerdp/utils/svc_plugin.h>
 
+enum _DRDYNVC_STATE
+{
+	DRDYNVC_STATE_INITIAL,
+	DRDYNVC_STATE_CAPABILITIES,
+	DRDYNVC_STATE_READY,
+	DRDYNVC_STATE_OPENING_CHANNEL,
+	DRDYNVC_STATE_SEND_RECEIVE,
+	DRDYNVC_STATE_FINAL
+};
+typedef enum _DRDYNVC_STATE DRDYNVC_STATE;
+
 #define CREATE_REQUEST_PDU		0x01
 #define DATA_FIRST_PDU			0x02
 #define DATA_PDU			0x03
@@ -38,6 +49,7 @@ struct drdynvc_plugin
 {
 	rdpSvcPlugin plugin;
 
+	DRDYNVC_STATE state;
 	DrdynvcClientContext* context;
 
 	int version;