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In-Game Packet Decompression

Started by Brand.X, February 13, 2003, 11:02 AM

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Brand.X

February 13, 2003, 11:02 AM Last Edit: December 31, 1969, 06:00 PM by 1048312800
This code is based on a disassembly from fog.dll.

Quote//----------------------------------------------------------------------
// Packet Decompression Tables
//----------------------------------------------------------------------

unsigned int CharIndex[] = {
    0x0247, 0x0236, 0x0225, 0x0214, 0x0203, 0x01F2, 0x01E1, 0x01D0,
    0x01BF, 0x01AE, 0x019D, 0x018C, 0x017B, 0x016A, 0x0161, 0x0158,
    0x014F, 0x0146, 0x013D, 0x0134, 0x012B, 0x0122, 0x0119, 0x0110,
    0x0107, 0x00FE, 0x00F5, 0x00EC, 0x00E3, 0x00DA, 0x00D1, 0x00C8,
    0x00BF, 0x00B6, 0x00AD, 0x00A8, 0x00A3, 0x009E, 0x0099, 0x0094,
    0x008F, 0x008A, 0x0085, 0x0080, 0x007B, 0x0076, 0x0071, 0x006C,
    0x0069, 0x0066, 0x0063, 0x0060, 0x005D, 0x005A, 0x0057, 0x0054,
    0x0051, 0x004E, 0x004B, 0x0048, 0x0045, 0x0042, 0x003F, 0x003F,
    0x003C, 0x003C, 0x0039, 0x0039, 0x0036, 0x0036, 0x0033, 0x0033,
    0x0030, 0x0030, 0x002D, 0x002D, 0x002A, 0x002A, 0x0027, 0x0027,
    0x0024, 0x0024, 0x0021, 0x0021, 0x001E, 0x001E, 0x001B, 0x001B,
    0x0018, 0x0018, 0x0015, 0x0015, 0x0012, 0x0012, 0x0012, 0x0012,
    0x000F, 0x000F, 0x000F, 0x000F, 0x000C, 0x000C, 0x000C, 0x000C,
    0x0009, 0x0009, 0x0009, 0x0009, 0x0006, 0x0006, 0x0006, 0x0006,
    0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003,
    0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003, 0x0003,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000
};


unsigned char CharTable[] = {
    0x00,0x00,0x01,0x00,0x01,0x04,0x00,0xFF,0x06,0x00,0x14,0x06,
    0x00,0x13,0x06,0x00,0x05,0x06,0x00,0x02,0x06,0x00,0x80,0x07,
    0x00,0x6D,0x07,0x00,0x69,0x07,0x00,0x68,0x07,0x00,0x67,0x07,
    0x00,0x1E,0x07,0x00,0x15,0x07,0x00,0x12,0x07,0x00,0x0D,0x07,
    0x00,0x0A,0x07,0x00,0x08,0x07,0x00,0x07,0x07,0x00,0x06,0x07,
    0x00,0x04,0x07,0x00,0x03,0x07,0x00,0x6C,0x08,0x00,0x51,0x08,
    0x00,0x20,0x08,0x00,0x1F,0x08,0x00,0x1D,0x08,0x00,0x18,0x08,
    0x00,0x17,0x08,0x00,0x16,0x08,0x00,0x11,0x08,0x00,0x10,0x08,
    0x00,0x0F,0x08,0x00,0x0C,0x08,0x00,0x0B,0x08,0x00,0x09,0x08,
    0x01,0x96,0x09,0x97,0x09,0x01,0x90,0x09,0x95,0x09,0x01,0x64,
    0x09,0x6B,0x09,0x01,0x62,0x09,0x63,0x09,0x01,0x56,0x09,0x58,
    0x09,0x01,0x52,0x09,0x55,0x09,0x01,0x4D,0x09,0x50,0x09,0x01,
    0x45,0x09,0x4C,0x09,0x01,0x40,0x09,0x43,0x09,0x01,0x31,0x09,
    0x3B,0x09,0x01,0x28,0x09,0x30,0x09,0x01,0x1A,0x09,0x25,0x09,
    0x01,0x0E,0x09,0x19,0x09,0x02,0xE2,0x0A,0xE8,0x0A,0xF0,0x0A,
    0xF8,0x0A,0x02,0xC0,0x0A,0xC2,0x0A,0xCE,0x0A,0xE0,0x0A,0x02,
    0xA0,0x0A,0xA2,0x0A,0xB0,0x0A,0xB8,0x0A,0x02,0x8A,0x0A,0x8F,
    0x0A,0x93,0x0A,0x98,0x0A,0x02,0x81,0x0A,0x82,0x0A,0x83,0x0A,
    0x89,0x0A,0x02,0x7C,0x0A,0x7D,0x0A,0x7E,0x0A,0x7F,0x0A,0x02,
    0x77,0x0A,0x78,0x0A,0x79,0x0A,0x7A,0x0A,0x02,0x73,0x0A,0x74,
    0x0A,0x75,0x0A,0x76,0x0A,0x02,0x6E,0x0A,0x6F,0x0A,0x70,0x0A,
    0x72,0x0A,0x02,0x61,0x0A,0x65,0x0A,0x66,0x0A,0x6A,0x0A,0x02,
    0x5D,0x0A,0x5E,0x0A,0x5F,0x0A,0x60,0x0A,0x02,0x57,0x0A,0x59,
    0x0A,0x5A,0x0A,0x5B,0x0A,0x02,0x4A,0x0A,0x4B,0x0A,0x4E,0x0A,
    0x53,0x0A,0x02,0x46,0x0A,0x47,0x0A,0x48,0x0A,0x49,0x0A,0x02,
    0x3F,0x0A,0x41,0x0A,0x42,0x0A,0x44,0x0A,0x02,0x3A,0x0A,0x3C,
    0x0A,0x3D,0x0A,0x3E,0x0A,0x02,0x36,0x0A,0x37,0x0A,0x38,0x0A,
    0x39,0x0A,0x02,0x32,0x0A,0x33,0x0A,0x34,0x0A,0x35,0x0A,0x02,
    0x2B,0x0A,0x2C,0x0A,0x2D,0x0A,0x2E,0x0A,0x02,0x26,0x0A,0x27,
    0x0A,0x29,0x0A,0x2A,0x0A,0x02,0x21,0x0A,0x22,0x0A,0x23,0x0A,
    0x24,0x0A,0x03,0xFB,0x0B,0xFC,0x0B,0xFD,0x0B,0xFE,0x0B,0x1B,
    0x0A,0x1B,0x0A,0x1C,0x0A,0x1C,0x0A,0x03,0xF2,0x0B,0xF3,0x0B,
    0xF4,0x0B,0xF5,0x0B,0xF6,0x0B,0xF7,0x0B,0xF9,0x0B,0xFA,0x0B,
    0x03,0xE9,0x0B,0xEA,0x0B,0xEB,0x0B,0xEC,0x0B,0xED,0x0B,0xEE,
    0x0B,0xEF,0x0B,0xF1,0x0B,0x03,0xDE,0x0B,0xDF,0x0B,0xE1,0x0B,
    0xE3,0x0B,0xE4,0x0B,0xE5,0x0B,0xE6,0x0B,0xE7,0x0B,0x03,0xD6,
    0x0B,0xD7,0x0B,0xD8,0x0B,0xD9,0x0B,0xDA,0x0B,0xDB,0x0B,0xDC,
    0x0B,0xDD,0x0B,0x03,0xCD,0x0B,0xCF,0x0B,0xD0,0x0B,0xD1,0x0B,
    0xD2,0x0B,0xD3,0x0B,0xD4,0x0B,0xD5,0x0B,0x03,0xC5,0x0B,0xC6,
    0x0B,0xC7,0x0B,0xC8,0x0B,0xC9,0x0B,0xCA,0x0B,0xCB,0x0B,0xCC,
    0x0B,0x03,0xBB,0x0B,0xBC,0x0B,0xBD,0x0B,0xBE,0x0B,0xBF,0x0B,
    0xC1,0x0B,0xC3,0x0B,0xC4,0x0B,0x03,0xB2,0x0B,0xB3,0x0B,0xB4,
    0x0B,0xB5,0x0B,0xB6,0x0B,0xB7,0x0B,0xB9,0x0B,0xBA,0x0B,0x03,
    0xA9,0x0B,0xAA,0x0B,0xAB,0x0B,0xAC,0x0B,0xAD,0x0B,0xAE,0x0B,
    0xAF,0x0B,0xB1,0x0B,0x03,0x9F,0x0B,0xA1,0x0B,0xA3,0x0B,0xA4,
    0x0B,0xA5,0x0B,0xA6,0x0B,0xA7,0x0B,0xA8,0x0B,0x03,0x92,0x0B,
    0x94,0x0B,0x99,0x0B,0x9A,0x0B,0x9B,0x0B,0x9C,0x0B,0x9D,0x0B,
    0x9E,0x0B,0x03,0x86,0x0B,0x87,0x0B,0x88,0x0B,0x8B,0x0B,0x8C,
    0x0B,0x8D,0x0B,0x8E,0x0B,0x91,0x0B,0x03,0x2F,0x0B,0x4F,0x0B,
    0x54,0x0B,0x5C,0x0B,0x71,0x0B,0x7B,0x0B,0x84,0x0B,0x85,0x0B
};

unsigned int BitMasks[] = {
    0x0000,0x0001,0x0003,0x0007,0x000F,0x001F,0x003F,0x007F,
    0x00FF,0x01FF,0x03FF,0x07FF,0x0FFF,0x1FFF,0x3FFF,0x7FFF
};

//----------------------------------------------------------------------
// GamePacketSize
//   Calculates the size of a compressed game packet.
//  
// data: [in] pointer to received packet
// size: [out] pointer to size
// returns: the offset to the data.
//----------------------------------------------------------------------

unsigned char *GamePacketSize(unsigned char *data, unsigned int *size,
                              unsigned int *offset)
{
    unsigned int a;

    if (data[0] < 0xF0) {
        *size = data[0] - 1;
        *offset = 1;
        return &data[1];
    }

    a = (data[0] & 0xF) << 8;
    *size = a + data[1] - 2;
    *offset = 2;
    return &data[2];
}

//----------------------------------------------------------------------
// GamePacketDecode
//   Decompress a d2gs packet into data.
//   Note: packets come in clumps. A single compressed packet may have
//   several game packets, and its up to you to figure it out.
//
// indata: [in] compressed packet (without size byte)
// insize: [in] length of indata
// outdata: [out] output buffer
// outmax: [in] size of output buffer
// outsize: [out] location to store size of decoded data
// returns: 1 on successf decode, 0 if not enough room
//----------------------------------------------------------------------

int GamePacketDecode(unsigned char *indata, unsigned int insize,
                     unsigned char *outdata, unsigned int outmax,
                     unsigned int *outsize)
{
    unsigned int a, b, c, d;
    unsigned int maxcnt, index, cnt;
    unsigned char *outptr, *inptr;
    int size;

    b = 0;

    size = insize;
    inptr = indata;

    maxcnt = outmax;
    outptr = outdata;
    cnt = 0x20;

    while (1) {

        if (cnt >= 0x8) {
            while (size > 0 && cnt >= 8) {
                cnt -= 0x8;
                size--;
                a = *inptr++ << cnt;
                b |= a;
            };
        }

        index = CharIndex[b >> 0x18];
        a = CharTable[index];
        d = (b >> (0x18 - a)) & BitMasks[a];
        c = CharTable[index + 2*d + 2];

        cnt += c;
        if (cnt > 0x20) {
            *outsize = outmax - maxcnt;
            return 1;
        }

        if (maxcnt-- == 0)
            return 0;

        a = CharTable[index + 2*d + 1];
        *outptr++ = (unsigned char)a;

        b <<= (c & 0xFF);
    }

    assert(0);
    return 0;
}

dxoigmn

#1
February 13, 2003, 12:19 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
Ahh...nice.  I was looking into this but my skill at converting ASM to C++ is horrible.  Thanks ;).

talon60k

#2
February 14, 2003, 02:44 AM Last Edit: December 31, 1969, 06:00 PM by 1048312800
nice!

Brand.X

#3
February 15, 2003, 07:19 AM Last Edit: December 31, 1969, 06:00 PM by 1048312800
The work was mostly stepping through function calls with SoftICE trying to find where decompression was happening. And the dumping of the memory which contained the tables. It was a lot easier than I expected; thanks to Blizzard's clean code.

People had this information before but kept it private. Not mentioning any names, but I hope it will speed up bot development in general.

l)ragon

#4
February 15, 2003, 12:51 PM
QuoteThe work was mostly stepping through function calls with SoftICE trying to find where decompression was happening. And the dumping of the memory which contained the tables. It was a lot easier than I expected; thanks to Blizzard's clean code.

People had this information before but kept it private. Not mentioning any names, but I hope it will speed up bot development in general.

it was not private it is in the hackit source code if i remember correctly.

*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*ˆ¨¯¯¨ˆ*^~·.,l)ragon,.-·~^*ˆ¨¯¯¨ˆ*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*

l)ragon

#5
February 15, 2003, 01:17 PM
in any case maybe someone will sticky this thread due to the point lots of people were looking for this.

maybe we will see some d2gs talk now ^^
*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*ˆ¨¯¯¨ˆ*^~·.,l)ragon,.-·~^*ˆ¨¯¯¨ˆ*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*

Noodlez

#6
February 15, 2003, 04:33 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
now im not special anymore :(

dragon it was private, d2hackit intercepted packets after they were decompressed. oh well, atleast my gamebots done :P

l)ragon

#7
February 15, 2003, 05:42 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
Quotenow im not special anymore :(

dragon it was private, d2hackit intercepted packets after they were decompressed. oh well, atleast my gamebots done :P

you'll get over it. :P

to anyone that can see the decompressed data, PM me.

kthx
*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*ˆ¨¯¯¨ˆ*^~·.,l)ragon,.-·~^*ˆ¨¯¯¨ˆ*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*

talon60k

#8
February 17, 2003, 03:45 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
Quotenow im not special anymore :(

dragon it was private, d2hackit intercepted packets after they were decompressed. oh well, atleast my gamebots done :P

when u gonna release it tho ?

yeah, that decompression was private, i figured out my own version also. my bots pretty much done tho also, so hopefully there wont be too many bots!

Noodlez

#9
February 19, 2003, 07:22 PM
and maybe when your communist ass dies ill spit on your grave

talon60k

#10
February 20, 2003, 04:38 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
Quoteand maybe when your communist ass dies ill spit on your grave

lmao, me or dragon ?

c0ke

#11
February 20, 2003, 05:05 PM Last Edit: December 31, 1969, 06:00 PM by 1048312800
Quotenow im not special anymore :(

dragon it was private, d2hackit intercepted packets after they were decompressed. oh well, atleast my gamebots done :P

Noodlez; special because you were given first Yobguls', then Talon's decompression source?

(sorry in advance, this is for flaming me on blizzhackers)

Noodlez

#12
February 20, 2003, 05:47 PM
talon, was talking to warz  not you :p
but he removed his post, guess he didn't want people to see it.

l)ragon

#13
May 31, 2003, 02:44 AM Last Edit: May 31, 2003, 02:04 PM by dRAgoN
* dRAgoN kicks topic back to the top of the list

This is a rather usefull topic.
Would someone Pin it or some thing along with the .BNI tut. Kain posted this way there both up at the top and noone asks + then theres also no need to search it out 8p

Quote from: laurion on May 31, 2003, 06:14 AM
Quote from: dRAgoN on May 31, 2003, 02:44 AM
* dRAgoN kicks topic back to the top of the list

This is a rather usefull topic.
Would someone Pin it or some thing along with the .BNI tut. Kain posted this way there both up at the top and noone asks + then theres also no need to search it out 8p
the BNI tut is on http://botdev.valhallalegends.com/

forgot about that
*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*ˆ¨¯¯¨ˆ*^~·.,l)ragon,.-·~^*ˆ¨¯¯¨ˆ*^~·.,¸¸,.·´¯`·.,¸¸,.-·~^*

Tazo

#14
May 31, 2003, 06:14 AM
Quote from: dRAgoN on May 31, 2003, 02:44 AM
* dRAgoN kicks topic back to the top of the list

This is a rather usefull topic.
Would someone Pin it or some thing along with the .BNI tut. Kain posted this way there both up at the top and noone asks + then theres also no need to search it out 8p
the BNI tut is on http://botdev.valhallalegends.com/
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