diff options
Diffstat (limited to 'libxrdp/xrdp_mppc_enc.c')
| -rw-r--r-- | libxrdp/xrdp_mppc_enc.c | 1047 |
1 files changed, 1047 insertions, 0 deletions
diff --git a/libxrdp/xrdp_mppc_enc.c b/libxrdp/xrdp_mppc_enc.c new file mode 100644 index 00000000..f94b7e6a --- /dev/null +++ b/libxrdp/xrdp_mppc_enc.c @@ -0,0 +1,1047 @@ +/** + * FreeRDP: A Remote Desktop Protocol Implementation + * 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 "libxrdp.h" + +#define MPPC_ENC_DEBUG 0 + +#if MPPC_ENC_DEBUG +#define DLOG(_args) g_printf _args +#else +#define DLOG(_args) do { } while (0) +#endif + +/* 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 */ + +/* Compression Types */ +#define PACKET_COMPRESSED 0x20 +#define PACKET_AT_FRONT 0x40 +#define PACKET_FLUSHED 0x80 +#define PACKET_COMPR_TYPE_8K 0x00 +#define PACKET_COMPR_TYPE_64K 0x01 +#define PACKET_COMPR_TYPE_RDP6 0x02 +#define PACKET_COMPR_TYPE_RDP61 0x03 +#define CompressionTypeMask 0x0F + +#define CRC_INIT 0xFFFF +#define CRC(_crcval, _newchar) _crcval = \ + ((_crcval) >> 8) ^ g_crc_table[((_crcval) ^ (_newchar)) & 0x00ff] + +/* CRC16 defs */ +static const tui16 g_crc_table[256] = +{ + 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, + 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, + 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, + 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, + 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, + 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, + 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, + 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, + 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, + 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, + 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, + 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, + 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, + 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, + 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, + 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, + 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, + 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, + 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, + 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, + 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, + 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, + 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, + 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, + 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, + 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, + 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, + 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, + 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, + 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, + 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, + 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 +}; + +/***************************************************************************** + 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) + +/** + * Initialize mppc_enc structure + * + * @param protocol_type PROTO_RDP_40 or PROTO_RDP_50 + * + * @return struct xrdp_mppc_enc* or nil on failure + */ + +struct xrdp_mppc_enc * APP_CC +mppc_enc_new(int protocol_type) +{ + struct xrdp_mppc_enc *enc; + + enc = (struct xrdp_mppc_enc *) g_malloc(sizeof(struct xrdp_mppc_enc), 1); + + if (enc == 0) + { + return 0; + } + + 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: + g_free(enc); + return 0; + } + + enc->first_pkt = 1; + enc->historyBuffer = (char *) g_malloc(enc->buf_len, 1); + + if (enc->historyBuffer == 0) + { + g_free(enc); + return 0; + } + + enc->outputBufferPlus = (char *) g_malloc(enc->buf_len + 64, 1); + + if (enc->outputBufferPlus == 0) + { + g_free(enc->historyBuffer); + g_free(enc); + return 0; + } + + enc->outputBuffer = enc->outputBufferPlus + 64; + enc->hash_table = (tui16 *) g_malloc(enc->buf_len * 2, 1); + + if (enc->hash_table == 0) + { + g_free(enc->historyBuffer); + g_free(enc->outputBufferPlus); + g_free(enc); + return 0; + } + + return enc; +} + +/** + * deinit mppc_enc structure + * + * @param enc struct to be deinited + */ + +void APP_CC +mppc_enc_free(struct xrdp_mppc_enc *enc) +{ + if (enc == 0) + { + return; + } + g_free(enc->historyBuffer); + g_free(enc->outputBufferPlus); + g_free(enc->hash_table); + g_free(enc); +} + +/** + * 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 + */ + +static int APP_CC +compress_rdp_4(struct xrdp_mppc_enc *enc, tui8 *srcData, int len) +{ + /* RDP 4.0 encoding not yet implemented */ + return 0; +} + +/** + * encode (compress) data using RDP 5.0 protocol using hash table + * + * @param enc encoder state info + * @param srcData uncompressed data + * @param len length of srcData + * + * @return TRUE on success, FALSE on failure + */ + +static int APP_CC +compress_rdp_5(struct xrdp_mppc_enc *enc, tui8 *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; + int opb_index; /* index into outputBuffer */ + int bits_left; /* unused bits in current byte in outputBuffer */ + tui32 copy_offset; /* pattern match starts here... */ + tui32 lom; /* ...and matches this many bytes */ + int last_crc_index; /* don't compute CRC beyond this index */ + tui16 *hash_table; /* hash table for pattern matching */ + + tui32 i; + tui32 j; + tui32 k; + tui32 x; + tui8 data; + tui16 data16; + tui32 historyOffset; + tui16 crc; + tui32 ctr; + tui32 saved_ctr; + tui32 data_end; + tui8 byte_val; + + crc = 0; + opb_index = 0; + bits_left = 8; + copy_offset = 0; + hash_table = enc->hash_table; + hbuf_start = enc->historyBuffer; + outputBuffer = enc->outputBuffer; + g_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; + g_memset(hash_table, 0, enc->buf_len * 2); + } + + /* point to next free byte in historyBuffer */ + historyOffset = enc->historyOffset; + + /* add / append new data to historyBuffer */ + g_memcpy(&(enc->historyBuffer[historyOffset]), srcData, len); + + /* point to start of data to be compressed */ + historyPointer = &(enc->historyBuffer[historyOffset]); + + ctr = copy_offset = lom = 0; + + /* if we are at start of history buffer, do not attempt to compress */ + /* first 2 bytes,because minimum LoM is 3 */ + if (historyOffset == 0) + { + /* encode first two bytes are literals */ + for (x = 0; x < 2; x++) + { + data = *(historyPointer + x); + DLOG(("%.2x ", (tui8) data)); + if (data & 0x80) + { + /* insert encoded literal */ + insert_2_bits(0x02); + data &= 0x7f; + insert_7_bits(data); + } + else + { + /* insert literal */ + insert_8_bits(data); + } + } + + /* store hash for first two entries in historyBuffer */ + crc = CRC_INIT; + byte_val = enc->historyBuffer[0]; + CRC(crc, byte_val); + byte_val = enc->historyBuffer[1]; + CRC(crc, byte_val); + byte_val = enc->historyBuffer[2]; + CRC(crc, byte_val); + hash_table[crc] = 0; + + crc = CRC_INIT; + byte_val = enc->historyBuffer[1]; + CRC(crc, byte_val); + byte_val = enc->historyBuffer[2]; + CRC(crc, byte_val); + byte_val = enc->historyBuffer[3]; + CRC(crc, byte_val); + hash_table[crc] = 1; + + /* first two bytes have already been processed */ + ctr = 2; + } + + enc->historyOffset += len; + + /* point to last byte in new data */ + hptr_end = &(enc->historyBuffer[enc->historyOffset - 1]); + + /* do not compute CRC beyond this */ + last_crc_index = enc->historyOffset - 3; + + /* do not search for pattern match beyond this */ + data_end = len - 2; + + /* start compressing data */ + + while (ctr < data_end) + { + cptr1 = historyPointer + ctr; + + crc = CRC_INIT; + byte_val = *cptr1; + CRC(crc, byte_val); + byte_val = *(cptr1 + 1); + CRC(crc, byte_val); + byte_val = *(cptr1 + 2); + CRC(crc, byte_val); + + /* cptr2 points to start of pattern match */ + cptr2 = hbuf_start + hash_table[crc]; + copy_offset = cptr1 - cptr2; + + /* save current entry */ + hash_table[crc] = cptr1 - hbuf_start; + + /* double check that we have a pattern match */ + if ((*cptr1 != *cptr2) || + (*(cptr1 + 1) != *(cptr2 + 1)) || + (*(cptr1 + 2) != *(cptr2 + 2))) + { + /* no match found; encode literal byte */ + data = *cptr1; + + DLOG(("%.2x ", data)); + if (data < 0x80) + { + /* literal byte < 0x80 */ + insert_8_bits(data); + } + else + { + /* literal byte >= 0x80 */ + insert_2_bits(0x02); + data &= 0x7f; + insert_7_bits(data); + } + ctr++; + continue; + } + + /* we have a match - compute Length of Match */ + cptr1 += 3; + cptr2 += 3; + lom = 3; + while ((cptr1 <= hptr_end) && (*(cptr1++) == *(cptr2++))) + { + lom++; + } + saved_ctr = ctr + lom; + DLOG(("<%d: %ld,%d> ", (historyPointer + ctr) - hbuf_start, + copy_offset, lom)); + + /* compute CRC for matching segment and store in hash table */ + + cptr1 = historyPointer + ctr; + if (cptr1 + lom > hbuf_start + last_crc_index) + { + /* we have gone beyond last_crc_index - go back */ + j = last_crc_index - (cptr1 - hbuf_start); + } + else + { + j = lom - 1; + } + ctr++; + for (i = 0; i < j; i++) + { + cptr1 = historyPointer + ctr; + + /* compute CRC on triplet */ + crc = CRC_INIT; + byte_val = *(cptr1++); + CRC(crc, byte_val); + byte_val = *(cptr1++); + CRC(crc, byte_val); + byte_val = *(cptr1++); + CRC(crc, byte_val); + + /* save current entry */ + hash_table[crc] = (cptr1 - 3) - hbuf_start; + + /* point to next triplet */ + ctr++; + } + ctr = saved_ctr; + + /* encode copy_offset and insert into output buffer */ + + if (copy_offset <= 63) /* (copy_offset >= 0) is always true */ + { + /* 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); + } + } /* end while (ctr < data_end) */ + + /* add remaining data to the output */ + while (len - ctr > 0) + { + data = srcData[ctr]; + DLOG(("%.2x ", data)); + if (data < 0x80) + { + /* literal byte < 0x80 */ + insert_8_bits(data); + } + else + { + /* literal byte >= 0x80 */ + insert_2_bits(0x02); + data &= 0x7f; + insert_7_bits(data); + } + ctr++; + } + + /* 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 = 0; + g_memset(hash_table, 0, enc->buf_len * 2); + enc->flagsHold |= PACKET_FLUSHED; + enc->first_pkt = 1; + return 1; + } + else if (opb_index + 1 > len) + { + /* compressed data longer than uncompressed data */ + /* give up */ + enc->historyOffset = 0; + g_memset(hash_table, 0, enc->buf_len * 2); + enc->flagsHold |= PACKET_FLUSHED; + enc->first_pkt = 1; + return 1; + } + + /* 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 = 0; + g_memset(hash_table, 0, enc->buf_len * 2); + enc->flagsHold |= PACKET_FLUSHED; + enc->first_pkt = 1; + return 1; + } + enc->flags |= PACKET_COMPRESSED; + enc->bytes_in_opb = opb_index; + + enc->flags |= enc->flagsHold; + enc->flagsHold = 0; + DLOG(("\n")); + + return 1; +} + +/** + * encode (compress) data + * + * @param enc encoder state info + * @param srcData uncompressed data + * @param len length of srcData + * + * @return TRUE on success, FALSE on failure + */ + +int APP_CC +compress_rdp(struct xrdp_mppc_enc *enc, tui8 *srcData, int len) +{ + if ((enc == 0) || (srcData == 0) || (len <= 0) || (len > enc->buf_len)) + { + return 0; + } + + 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 0; +} |