libfreerdp-core: started TPDU encoding/decoding

libfreerdp-core/CMakeLists.txt

@@ -30,6 +30,8 @@ set(LIBFREERDP_CORE_SRCS
 #	credssp.h
 #	ntlmssp.c
 #	ntlmssp.h
+	tpdu.c
+	tpdu.h
 	tpkt.c
 	tpkt.h
 )

libfreerdp-core/tpdu.c

@@ -0,0 +1,116 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Client
+ * X.224 Transport Protocol Data Units (TPDUs)
+ *
+ * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "tpdu.h"
+
+/**
+ * TPDUs are defined in:
+ *
+ * http://www.itu.int/rec/T-REC-X.224-199511-I/
+ * X.224: Information technology - Open Systems Interconnection - Protocol for providing the connection-mode transport service
+ *
+ * RDP uses only TPDUs of class 0, the "simple class" defined in section 8 of X.224
+ *
+ *       TPDU Header
+ *  ____________________   byte
+ * |                    |
+ * |         LI         |   1
+ * |____________________|
+ * |                    |
+ * |        Code        |   2
+ * |____________________|
+ * |                    |
+ * |                    |   3
+ * |_______DST-REF______|
+ * |                    |
+ * |                    |   4
+ * |____________________|
+ * |                    |
+ * |                    |   5
+ * |_______SRC-REF______|
+ * |                    |
+ * |                    |   6
+ * |____________________|
+ * |                    |
+ * |        Class       |   7
+ * |____________________|
+ * |         ...        |
+ */
+
+uint8
+tpdu_read_header(STREAM* s, uint16 length)
+{
+	uint8 li;
+	uint8 code;
+
+	stream_read_uint8(s, li); /* LI */
+	stream_read_uint8(s, code); /* Code */
+
+	if (code == X224_TPDU_DATA)
+	{
+		/* EOT (1 byte) */
+		stream_seek(s, 1);
+	}
+	else
+	{
+		/* DST-REF (2 bytes) */
+		/* SRC-REF (2 bytes) */
+		/* Class 0 (1 byte) */
+		stream_seek(s, 5);
+	}
+
+	return code;
+}
+
+void
+tpdu_write_header(STREAM* s, uint16 length, uint8 code)
+{
+	stream_write_uint8(s, length - 5); /* LI */
+	stream_write_uint8(s, code); /* code */
+
+	if (code == X224_TPDU_DATA)
+	{
+		stream_write_uint8(s, 0x80); /* EOT */
+	}
+	else
+	{
+		stream_write_uint16(s, 0); /* DST-REF */
+		stream_write_uint16(s, 0); /* SRC-REF */
+		stream_write_uint8(s, 0); /* Class 0 */
+	}
+}
+
+void
+tpdu_write_connection_request(STREAM* s, uint16 length)
+{
+	tpdu_write_header(s, length - 5, X224_TPDU_CONNECTION_REQUEST);
+	/* TODO: RDP_NEG_DATA */
+}
+
+void
+tpdu_write_disconnect_request(STREAM* s, uint16 length)
+{
+	tpdu_write_header(s, length - 5, X224_TPDU_DISCONNECT_REQUEST);
+}
+
+void
+tpdu_write_data(STREAM* s, uint16 length)
+{
+	tpdu_write_header(s, length - 5, X224_TPDU_DATA);
+}

libfreerdp-core/tpdu.h

@@ -0,0 +1,45 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Client
+ * X.224 Transport Protocol Data Units (TPDUs)
+ *
+ * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __TPDU_H
+#define __TPDU_H
+
+#include <freerdp/utils/stream.h>
+
+enum X224_TPDU_TYPE
+{
+	X224_TPDU_CONNECTION_REQUEST = 0xE0,
+	X224_TPDU_CONNECTION_CONFIRM = 0xD0,
+	X224_TPDU_DISCONNECT_REQUEST = 0x80,
+	X224_TPDU_DATA = 0xF0,
+	X224_TPDU_ERROR = 0x70
+};
+
+uint8
+tpdu_read_header(STREAM* s, uint16 length);
+void
+tpdu_write_header(STREAM* s, uint16 length, uint8 code);
+void
+tpdu_write_connection_request(STREAM* s, uint16 length);
+void
+tpdu_write_disconnect_request(STREAM* s, uint16 length);
+void
+tpdu_write_data(STREAM* s, uint16 length);
+
+#endif /* __TPDU_H */

libfreerdp-core/tpkt.c

@@ -1,6 +1,6 @@
 /**
  * FreeRDP: A Remote Desktop Protocol Client
- * TPKT Headers
+ * Transport Packets (TPKTs)
  *
  * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
  *
@@ -17,10 +17,12 @@
  * limitations under the License.
  */
 
+#include "tpdu.h"
+
 #include "tpkt.h"
 
 /**
- * TPKT headers are defined in:
+ * TPKTs are defined in:
  *
  * http://tools.ietf.org/html/rfc1006/
  * RFC 1006 - ISO Transport Service on top of the TCP
@@ -43,13 +45,15 @@
  * |    Length (LSB)    |   4
  * |____________________|
  * |                    |
- * |        TPDU        |   5 - ?
+ * |     X.224 TPDU     |   5 - ?
  *          ....
+ *
+ * A TPKT header is of fixed length 4, and the following X.224 TPDU is at least three bytes long.
+ * Therefore, the minimum TPKT length is 7, and the maximum TPKT length is 65535. Because the TPKT
+ * length includes the TPKT header (4 bytes), the maximum X.224 TPDU length is 65531.
  */
 
-#include <freerdp/utils/stream.h>
+uint16
-
-int
 tpkt_read_header(STREAM* s)
 {
 	uint8 version;
@@ -65,7 +69,7 @@ tpkt_read_header(STREAM* s)
 	else
 	{
 		/* not a TPKT header */
-		length = -1;
+		length = 0;
 	}
 
 	return length;

libfreerdp-core/tpkt.h

@@ -1,6 +1,6 @@
 /**
  * FreeRDP: A Remote Desktop Protocol Client
- * TPKT Headers
+ * Transport Packets (TPKTs)
  *
  * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
  *
@@ -22,9 +22,8 @@
 
 #include <freerdp/utils/stream.h>
 
-int
+uint16
 tpkt_read_header(STREAM* s);
-
 void
 tpkt_write_header(STREAM* s, int length);