FreeRDP/libfreerdp-core/tpdu.c
2011-07-03 19:27:02 -04:00

132 lines
2.9 KiB
C

/**
* 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 <stdio.h>
#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, uint8* code)
{
uint8 li;
stream_read_uint8(s, li); /* LI */
stream_read_uint8(s, *code); /* Code */
/* DST-REF (2 bytes) */
/* SRC-REF (2 bytes) */
/* Class 0 (1 byte) */
stream_seek(s, 5);
if (*code == X224_TPDU_DATA)
{
/* EOT (1 byte) */
stream_seek(s, 1);
}
return li;
}
void
tpdu_write_header(STREAM* s, uint16 length, uint8 code)
{
stream_write_uint8(s, length); /* 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, X224_TPDU_CONNECTION_REQUEST);
}
uint8
tpdu_read_connection_confirm(STREAM* s)
{
uint8 li;
uint8 code;
li = tpdu_read_header(s, &code);
if (code != X224_TPDU_CONNECTION_CONFIRM)
{
printf("Error: expected X224_TPDU_CONNECTION_CONFIRM\n");
return 0;
}
return li;
}
void
tpdu_write_disconnect_request(STREAM* s, uint16 length)
{
tpdu_write_header(s, length, X224_TPDU_DISCONNECT_REQUEST);
}
void
tpdu_write_data(STREAM* s, uint16 length)
{
tpdu_write_header(s, length, X224_TPDU_DATA);
}