public static Packet DecryptPacket(this Packet pkt)
{
byte[] buf = new byte[pkt.DecSpace];
byte counter = 0;
if (MU_DecodeC3C4(buf, 0, pkt, pkt.ToServer ? dec1_keys : dec2_keys, ref counter))
{
Packet dec = new Packet(buf, 0, pkt.ToServer, counter);
if (pkt.ToServer)
dec.DecodeC1C2();
return dec;
}
return null;
}
public static Packet EncryptPacket(this Packet pkt, Packet des_pkt = null)
{
if (pkt.ToServer)
pkt.EncodeC1C2();
if (des_pkt == null)
{
byte[] buf = new byte[pkt.EncSpace];
if (MU_EncodeC3C4(buf, 0, pkt, pkt.ToServer ? enc1_keys : enc2_keys, pkt.Counter))
return new Packet(buf, 0, pkt.ToServer, pkt.Counter);
}
else
if (MU_EncodeC3C4(des_pkt.Source, des_pkt.Index, pkt, pkt.ToServer ? enc1_keys : enc2_keys, pkt.Counter))
return des_pkt;
return null;
}
/// <summary>
/// encrypt c3/c4 packet
/// </summary>
static bool MU_EncodeC3C4(byte[] outbuffer, int outbuf, Packet pkt, uint[] dec_dat, byte enc_key)
{
byte hdrSize = pkt.HeaderSize;
byte hdr = pkt.Header;
byte tmp = pkt.Source[hdrSize - 1];
ushort enc_len = 0;
ushort size = pkt.Size;
pkt.Source[hdrSize - 1] = enc_key;
bool rs = MU_ForceEncodeC3C4(outbuffer, outbuf + hdrSize, ref enc_len, pkt.Source, pkt.Index + hdrSize - 1, (ushort)(size - hdrSize + 1), dec_dat);
pkt.Source[hdrSize - 1] = tmp;
if (rs == true)
{
outbuffer[outbuf] = (byte)(hdr + 2);
enc_len += (ushort)hdrSize;
if (hdrSize == 2)
outbuffer[outbuf + 1] = (byte)enc_len;
else
{
outbuffer[outbuf + 1] = (byte)((enc_len & ~0x00FF) >> 8);
outbuffer[outbuf + 2] = (byte)(enc_len & ~0xFF00);
}
}
return rs;
}
/// <summary>
/// encode c1/c2 packet
/// </summary>
static void MU_EncodeC1C2(Packet packet)
{
MU_ForceEncodeC1C2(packet.Source, packet.ContentIndex, packet.ContentSize, packet.HeaderSize);
}
/// <summary>
/// decrypt c3/c4 packet
/// </summary>
static bool MU_DecodeC3C4(byte[] outbuffer, int outbuf, Packet pkt, uint[] dec_dat, ref byte dec_key)
{
byte hdrSize = pkt.HeaderSize;
byte hdr = pkt.Header;
ushort dec_size = 0;
if (MU_ForceDecodeC3C4(outbuffer, outbuf + hdrSize - 1, ref dec_size, pkt.Source, pkt.ContentIndex, pkt.ContentSize, dec_dat) == false)
return false;// decryption fails
dec_size += (ushort)(hdrSize - 1);
dec_key = outbuffer[outbuf + hdrSize - 1];
outbuffer[outbuf] = (byte)(hdr - 2);
if (hdrSize == 2)
outbuffer[outbuf + 1] = (byte)dec_size;
else
{
outbuffer[outbuf + 1] = (byte)((dec_size & ~0x00FF) >> 8);
outbuffer[outbuf + 2] = (byte)(dec_size & ~0xFF00);
}
return true;// decrypt success
}
static int MuPacketEncSpace(Packet pkt)
{
ushort x = (ushort)(pkt.ContentSize + 1);
return (((x / 8) + (((x % 8) > 0) ? 1 : 0)) * 11) + pkt.HeaderSize;
}
static int MuPacketDecSpace(Packet pkt)
{
return ((pkt.ContentSize / 11) * 8) + pkt.HeaderSize - 1;
}
