66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Client
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* Fast Path
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*
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* Copyright 2011 Vic Lee
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <freerdp/utils/stream.h>
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#include "fastpath.h"
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/**
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* Fast-Path packet format is defined in [MS-RDPBCGR] 2.2.9.1.2, which revises
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* server output packets from the first byte with the goal of improving
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* bandwidth.
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*
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* Slow-Path packet always starts with TPKT header, which has the first
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* byte 0x03, while Fast-Path packet starts with 2 zero bits in the first
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* two less significant bits of the first byte.
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*/
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/**
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* Read a Fast-Path packet header.\n
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* @param s stream
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* @param encryptionFlags
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* @return length
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*/
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uint16 fastpath_read_header(STREAM* s, uint8* encryptionFlags)
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{
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uint8 header;
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uint16 length;
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uint8 t;
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stream_read_uint8(s, header);
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if (encryptionFlags != NULL)
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*encryptionFlags = (header & 0xC0) >> 6;
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stream_read_uint8(s, length); /* length1 */
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/* If most significant bit is not set, length2 is not presented. */
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if ((length & 0x80))
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{
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length &= 0x7F;
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length <<= 8;
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stream_read_uint8(s, t);
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length += t;
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}
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return length;
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}
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