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FreeRDP/libfreerdp-core/mppc_enc.c

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/**
* FreeRDP: A Remote Desktop Protocol Client
* Implements Microsoft Point to Point Compression (MPPC) protocol
*
* Copyright 2012 Laxmikant Rashinkar <LK.Rashinkar@gmail.com>
* Copyright 2012 Jay Sorg <jay.sorg@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 "rdp.h"
#include "mppc_enc.h"
#include <freerdp/utils/memory.h>
#define MPPC_ENC_DEBUG 0
/* local defines */
#define RDP_40_HIST_BUF_LEN (1024 * 8) /* RDP 4.0 uses 8K history buf */
#define RDP_50_HIST_BUF_LEN (1024 * 64) /* RDP 5.0 uses 64K history buf */
/*****************************************************************************
insert 2 bits into outputBuffer
******************************************************************************/
#define insert_2_bits(_data) \
do \
{ \
if ((bits_left >= 3) && (bits_left <= 8)) \
{ \
i = bits_left - 2; \
outputBuffer[opb_index] |= _data << i; \
bits_left = i; \
} \
else \
{ \
i = 2 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 3 bits into outputBuffer
******************************************************************************/
#define insert_3_bits(_data) \
do \
{ \
if ((bits_left >= 4) && (bits_left <= 8)) \
{ \
i = bits_left - 3; \
outputBuffer[opb_index] |= _data << i; \
bits_left = i; \
} \
else \
{ \
i = 3 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 4 bits into outputBuffer
******************************************************************************/
#define insert_4_bits(_data) \
do \
{ \
if ((bits_left >= 5) && (bits_left <= 8)) \
{ \
i = bits_left - 4; \
outputBuffer[opb_index] |= _data << i; \
bits_left = i; \
} \
else \
{ \
i = 4 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 5 bits into outputBuffer
******************************************************************************/
#define insert_5_bits(_data) \
do \
{ \
if ((bits_left >= 6) && (bits_left <= 8)) \
{ \
i = bits_left - 5; \
outputBuffer[opb_index] |= _data << i; \
bits_left = i; \
} \
else \
{ \
i = 5 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 6 bits into outputBuffer
******************************************************************************/
#define insert_6_bits(_data) \
do \
{ \
if ((bits_left >= 7) && (bits_left <= 8)) \
{ \
i = bits_left - 6; \
outputBuffer[opb_index] |= (_data << i); \
bits_left = i; \
} \
else \
{ \
i = 6 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= (_data >> i); \
outputBuffer[opb_index] |= (_data << j); \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 7 bits into outputBuffer
******************************************************************************/
#define insert_7_bits(_data) \
do \
{ \
if (bits_left == 8) \
{ \
outputBuffer[opb_index] |= _data << 1; \
bits_left = 1; \
} \
else \
{ \
i = 7 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 8 bits into outputBuffer
******************************************************************************/
#define insert_8_bits(_data) \
do \
{ \
if (bits_left == 8) \
{ \
outputBuffer[opb_index++] |= _data; \
bits_left = 8; \
} \
else \
{ \
i = 8 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= _data >> i; \
outputBuffer[opb_index] |= _data << j; \
bits_left = j; \
} \
} while (0)
/*****************************************************************************
insert 9 bits into outputBuffer
******************************************************************************/
#define insert_9_bits(_data16) \
do \
{ \
i = 9 - bits_left; \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
if (bits_left == 0) \
{ \
opb_index++; \
bits_left = 8; \
} \
} while (0)
/*****************************************************************************
insert 10 bits into outputBuffer
******************************************************************************/
#define insert_10_bits(_data16) \
do \
{ \
i = 10 - bits_left; \
if ((bits_left >= 3) && (bits_left <= 8)) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 11 bits into outputBuffer
******************************************************************************/
#define insert_11_bits(_data16) \
do \
{ \
i = 11 - bits_left; \
if ((bits_left >= 4) && (bits_left <= 8)) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 12 bits into outputBuffer
******************************************************************************/
#define insert_12_bits(_data16) \
do \
{ \
i = 12 - bits_left; \
if ((bits_left >= 5) && (bits_left <= 8)) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 13 bits into outputBuffer
******************************************************************************/
#define insert_13_bits(_data16) \
do \
{ \
i = 13 - bits_left; \
if ((bits_left >= 6) && (bits_left <= 8)) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 14 bits into outputBuffer
******************************************************************************/
#define insert_14_bits(_data16) \
do \
{ \
i = 14 - bits_left; \
if ((bits_left >= 7) && (bits_left <= 8)) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 15 bits into outputBuffer
******************************************************************************/
#define insert_15_bits(_data16) \
do \
{ \
i = 15 - bits_left; \
if (bits_left == 8) \
{ \
j = 8 - i; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index] |= (char) (_data16 << j); \
bits_left = j; \
} \
else \
{ \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} \
} while (0)
/*****************************************************************************
insert 16 bits into outputBuffer
******************************************************************************/
#define insert_16_bits(_data16) \
do \
{ \
i = 16 - bits_left; \
j = i - 8; \
k = 8 - j; \
outputBuffer[opb_index++] |= (char) (_data16 >> i); \
outputBuffer[opb_index++] |= (char) (_data16 >> j); \
outputBuffer[opb_index] |= (char) (_data16 << k); \
bits_left = k; \
} while (0)
#if MPPC_ENC_DEBUG
#define DLOG(_args) printf _args
#else
#define DLOG(_args) do { } while (0)
#endif
/**
* Initialize mppc_enc structure
*
* @param protocol_type PROTO_RDP_40 or PROTO_RDP_50
*
* @return struct rdp_mppc_enc* or nil on failure
*/
struct rdp_mppc_enc* mppc_enc_new(int protocol_type)
{
struct rdp_mppc_enc* enc;
enc = xnew(struct rdp_mppc_enc);
if (enc == NULL)
return NULL;
switch (protocol_type)
{
case PROTO_RDP_40:
enc->protocol_type = PROTO_RDP_40;
enc->buf_len = RDP_40_HIST_BUF_LEN;
break;
case PROTO_RDP_50:
enc->protocol_type = PROTO_RDP_50;
enc->buf_len = RDP_50_HIST_BUF_LEN;
break;
default:
xfree(enc);
return NULL;
}
enc->first_pkt = 1;
enc->historyBuffer = (char*) xzalloc(enc->buf_len);
if (enc->historyBuffer == NULL)
{
xfree(enc);
return NULL;
}
enc->outputBufferPlus = (char*) xzalloc(enc->buf_len + 32);
if (enc->outputBufferPlus == NULL)
{
xfree(enc->historyBuffer);
xfree(enc);
return NULL;
}
enc->outputBuffer = enc->outputBufferPlus + 32;
return enc;
}
/**
* deinit mppc_enc structure
*
* @param enc struct to be deinited
*/
void mppc_enc_free(struct rdp_mppc_enc* enc)
{
if (enc == NULL)
return;
xfree(enc->historyBuffer);
xfree(enc->outputBufferPlus);
xfree(enc);
}
/**
* encode (compress) data
*
* @param enc encoder state info
* @param srcData uncompressed data
* @param len length of srcData
*
* @return true on success, false on failure
*/
boolean compress_rdp(struct rdp_mppc_enc* enc, uint8* srcData, int len)
{
if ((enc == NULL) || (srcData == NULL) || (len <= 0) || (len > enc->buf_len))
return false;
switch (enc->protocol_type)
{
case PROTO_RDP_40:
return compress_rdp_4(enc, srcData, len);
break;
case PROTO_RDP_50:
return compress_rdp_5(enc, srcData, len);
break;
}
return false;
}
/**
* encode (compress) data using RDP 4.0 protocol
*
* @param enc encoder state info
* @param srcData uncompressed data
* @param len length of srcData
*
* @return true on success, false on failure
*/
boolean compress_rdp_4(struct rdp_mppc_enc* enc, uint8* srcData, int len)
{
/* RDP 4.0 encoding not yet implemented */
return false;
}
/**
* encode (compress) data using RDP 5.0 protocol
*
* @param enc encoder state info
* @param srcData uncompressed data
* @param len length of srcData
*
* @return true on success, false on failure
*/
boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
{
char* outputBuffer; /* points to enc->outputBuffer */
char* hptr_end; /* points to end of history data */
char* historyPointer; /* points to first byte of srcData in historyBuffer */
char* hbuf_start; /* points to start of history buffer */
char* cptr1;
char* cptr2;
char* cptr3;
char* index_ptr;
int opb_index; /* index into outputBuffer */
int bits_left; /* unused bits in current byte in outputBuffer */
uint32 copy_offset; /* pattern match starts here... */
uint32 lom; /* ...and matches this many bytes */
uint32 saved_lom;
uint32 i;
uint32 j;
uint32 k;
uint32 x;
uint8 data;
uint16 data16;
uint32 historyOffset;
opb_index = 0;
bits_left = 8;
copy_offset = 0;
hbuf_start = enc->historyBuffer;
outputBuffer = enc->outputBuffer;
memset(outputBuffer, 0, len);
enc->flags = PACKET_COMPR_TYPE_64K;
if (enc->first_pkt)
{
enc->first_pkt = 0;
enc->flagsHold |= PACKET_AT_FRONT;
}
if ((enc->historyOffset + len) > enc->buf_len)
{
/* historyBuffer cannot hold srcData - rewind it */
enc->historyOffset = 0;
enc->flagsHold |= PACKET_AT_FRONT;
}
historyOffset = enc->historyOffset;
/* add / append new data to historyBuffer */
memcpy(&(enc->historyBuffer[enc->historyOffset]), srcData, len);
historyPointer = &(enc->historyBuffer[enc->historyOffset]);
/* if we are at start of history buffer, do not attempt to compress */
/* first 2 bytes,because minimum LoM is 3 */
if (enc->historyOffset == 0)
{
for (x = 0; x < 2; x++)
{
data = *(historyPointer++);
DLOG(("%.2x ", (unsigned char) data));
if (data & 0x80)
{
/* insert encoded literal */
insert_2_bits(0x02);
data &= 0x7f;
insert_7_bits(data);
}
else
{
/* insert literal */
insert_8_bits(data);
}
}
}
enc->historyOffset += len;
/* point to last byte in new data */
hptr_end = &(enc->historyBuffer[enc->historyOffset - 1]);
while (historyPointer <= hptr_end)
{
/* do not search beyond index_ptr */
index_ptr = (historyPointer == hptr_end) ? historyPointer - 2 : historyPointer - 1;
cptr1 = hbuf_start;
lom = 0;
saved_lom = 0;
while (1)
{
/* look for first byte match */
while ((cptr1 <= index_ptr) && (*cptr1 != *historyPointer))
{
cptr1++;
}
if (cptr1 > index_ptr)
{
break;
}
/* got a one byte match - continue looking */
lom = 1;
cptr1++;
cptr2 = cptr1;
cptr3 = historyPointer + 1;
while (*(cptr2++) == *(cptr3++))
{
lom++;
if (cptr3 > hptr_end)
{
break;
}
}
if (lom < 3)
{
/* false alarm, keep looking */
lom = 0;
}
else
{
if (lom >= saved_lom)
{
/* this is a longer match, or a match closer to historyPointer */
saved_lom = lom;
copy_offset = (historyPointer - cptr1) + 1;
}
}
}
if (saved_lom)
{
/* insert_tuple */
DLOG(("<%d: %ld,%d> ", (int) (historyPointer - enc->historyBuffer),
(long) copy_offset, saved_lom));
lom = saved_lom;
historyPointer += lom;
/*
** encode copy_offset and insert into output buffer
*/
if ((copy_offset >= 0) && (copy_offset <= 63))
{
/* insert binary header */
data = 0x1f;
insert_5_bits(data);
/* insert 6 bits of copy_offset */
data = (char) (copy_offset & 0x3f);
insert_6_bits(data);
}
else if ((copy_offset >= 64) && (copy_offset <= 319))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert 8 bits of copy offset */
data = (char) (copy_offset - 64);
insert_8_bits(data);
}
else if ((copy_offset >= 320) && (copy_offset <= 2367))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert 11 bits of copy offset */
data16 = copy_offset - 320;;
insert_11_bits(data16);
}
else
{
/* copy_offset is 2368+ */
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert 16 bits of copy offset */
data16 = copy_offset - 2368;;
insert_16_bits(data16);
}
/*
** encode length of match and insert into output buffer
*/
if (lom == 3)
{
/* binary header is 'zero'; since outputBuffer is zero */
/* filled, all we have to do is update bits_left */
bits_left--;
if (bits_left == 0)
{
opb_index++;
bits_left = 8;
}
}
else if ((lom >= 4) && (lom <= 7))
{
/* insert binary header */
data = 0x02;
insert_2_bits(data);
/* insert lower 2 bits of LoM */
data = (char) (lom - 4);
insert_2_bits(data);
}
else if ((lom >= 8) && (lom <= 15))
{
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert lower 3 bits of LoM */
data = (char) (lom - 8);
insert_3_bits(data);
}
else if ((lom >= 16) && (lom <= 31))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert lower 4 bits of LoM */
data = (char) (lom - 16);
insert_4_bits(data);
}
else if ((lom >= 32) && (lom <= 63))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert lower 5 bits of LoM */
data = (char) (lom - 32);
insert_5_bits(data);
}
else if ((lom >= 64) && (lom <= 127))
{
/* insert binary header */
data = 0x3e;
insert_6_bits(data);
/* insert lower 6 bits of LoM */
data = (char) (lom - 64);
insert_6_bits(data);
}
else if ((lom >= 128) && (lom <= 255))
{
/* insert binary header */
data = 0x7e;
insert_7_bits(data);
/* insert lower 7 bits of LoM */
data = (char) (lom - 128);
insert_7_bits(data);
}
else if ((lom >= 256) && (lom <= 511))
{
/* insert binary header */
data = 0xfe;
insert_8_bits(data);
/* insert lower 8 bits of LoM */
data = (char) (lom - 256);
insert_8_bits(data);
}
else if ((lom >= 512) && (lom <= 1023))
{
/* insert binary header */
data16 = 0x1fe;
insert_9_bits(data16);
/* insert lower 9 bits of LoM */
data16 = lom - 512;
insert_9_bits(data16);
}
else if ((lom >= 1024) && (lom <= 2047))
{
/* insert binary header */
data16 = 0x3fe;
insert_10_bits(data16);
/* insert 10 lower bits of LoM */
data16 = lom - 1024;
insert_10_bits(data16);
}
else if ((lom >= 2048) && (lom <= 4095))
{
/* insert binary header */
data16 = 0x7fe;
insert_11_bits(data16);
/* insert 11 lower bits of LoM */
data16 = lom - 2048;
insert_11_bits(data16);
}
else if ((lom >= 4096) && (lom <= 8191))
{
/* insert binary header */
data16 = 0xffe;
insert_12_bits(data16);
/* insert 12 lower bits of LoM */
data16 = lom - 4096;
insert_12_bits(data16);
}
else if ((lom >= 8192) && (lom <= 16383))
{
/* insert binary header */
data16 = 0x1ffe;
insert_13_bits(data16);
/* insert 13 lower bits of LoM */
data16 = lom - 8192;
insert_13_bits(data16);
}
else if ((lom >= 16384) && (lom <= 32767))
{
/* insert binary header */
data16 = 0x3ffe;
insert_14_bits(data16);
/* insert 14 lower bits of LoM */
data16 = lom - 16384;
insert_14_bits(data16);
}
else if ((lom >= 32768) && (lom <= 65535))
{
/* insert binary header */
data16 = 0x7ffe;
insert_15_bits(data16);
/* insert 15 lower bits of LoM */
data16 = lom - 32768;
insert_15_bits(data16);
}
}
else
{
/* insert_literal */
/* data not found in historyBuffer; encode and place data in output buffer */
data = *(historyPointer++);
DLOG(("%.2x ", (unsigned char) data));
if (data & 0x80)
{
/* insert encoded literal */
insert_2_bits(0x02);
data &= 0x7f;
insert_7_bits(data);
}
else
{
/* insert literal */
insert_8_bits(data);
}
}
/* if bits_left == 8, opb_index has already been incremented */
if ((bits_left == 8) && (opb_index > len))
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = historyOffset;
return true;
}
else if (opb_index + 1 > len)
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = historyOffset;
return true;
}
} /* end while (historyPointer < hptr_end) */
/* if bits_left != 8, increment opb_index, which is zero indexed */
if (bits_left != 8)
{
opb_index++;
}
if (opb_index > len)
{
/* give up */
enc->historyOffset = historyOffset;
return true;
}
enc->flags |= PACKET_COMPRESSED;
enc->bytes_in_opb = opb_index;
enc->flags |= enc->flagsHold;
enc->flagsHold = 0;
DLOG(("\n"));
return true;
}
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