Implements a 32-bit CRC hash algorithm compatible with Zip etc.
Crc32 should only be used for backward compatibility with older file formats and algorithms. It is not secure enough for new applications. If you need to call multiple times for the same data either use the HashAlgorithm interface or remember that the result of one Compute call needs to be ~ (XOR) before being passed in as the seed for the next Compute call.
Inheritance: HashAlgorithm
示例#1
0
        private void ProcessIncoming(byte[] localMsg, IPEndPoint clientEP)
        {
            try
            {
                int currIdx = 0;
                if (localMsg[0] != 'D' || localMsg[1] != 'S' || localMsg[2] != 'U' || localMsg[3] != 'C')
                {
                    return;
                }
                else
                {
                    currIdx += 4;
                }

                uint protocolVer = BitConverter.ToUInt16(localMsg, currIdx);
                currIdx += 2;

                if (protocolVer > MaxProtocolVersion)
                {
                    return;
                }

                uint packetSize = BitConverter.ToUInt16(localMsg, currIdx);
                currIdx += 2;

                if (packetSize < 0)
                {
                    return;
                }

                packetSize += 16; //size of header
                if (packetSize > localMsg.Length)
                {
                    return;
                }
                else if (packetSize < localMsg.Length)
                {
                    byte[] newMsg = new byte[packetSize];
                    Array.Copy(localMsg, newMsg, packetSize);
                    localMsg = newMsg;
                }

                uint crcValue = BitConverter.ToUInt32(localMsg, currIdx);
                //zero out the crc32 in the packet once we got it since that's whats needed for calculation
                localMsg[currIdx++] = 0;
                localMsg[currIdx++] = 0;
                localMsg[currIdx++] = 0;
                localMsg[currIdx++] = 0;

                uint crcCalc = Crc32Algorithm.Compute(localMsg);
                if (crcValue != crcCalc)
                {
                    return;
                }

                uint clientId = BitConverter.ToUInt32(localMsg, currIdx);
                currIdx += 4;

                uint messageType = BitConverter.ToUInt32(localMsg, currIdx);
                currIdx += 4;

                if (messageType == (uint)MessageType.DSUC_VersionReq)
                {
                    byte[] outputData = new byte[8];
                    int    outIdx     = 0;
                    Array.Copy(BitConverter.GetBytes((uint)MessageType.DSUS_VersionRsp), 0, outputData, outIdx, 4);
                    outIdx += 4;
                    Array.Copy(BitConverter.GetBytes((ushort)MaxProtocolVersion), 0, outputData, outIdx, 2);
                    outIdx += 2;
                    outputData[outIdx++] = 0;
                    outputData[outIdx++] = 0;

                    SendPacket(clientEP, outputData, 1001);
                }
                else if (messageType == (uint)MessageType.DSUC_ListPorts)
                {
                    int numPadRequests = BitConverter.ToInt32(localMsg, currIdx);
                    currIdx += 4;
                    if (numPadRequests < 0 || numPadRequests > 4)
                    {
                        return;
                    }

                    int requestsIdx = currIdx;
                    for (int i = 0; i < numPadRequests; i++)
                    {
                        byte currRequest = localMsg[requestsIdx + i];
                        if (currRequest >= 4)
                        {
                            return;
                        }
                    }

                    byte[] outputData = new byte[16];
                    for (byte i = 0; i < numPadRequests; i++)
                    {
                        byte             currRequest = localMsg[requestsIdx + i];
                        DualShockPadMeta padData     = new DualShockPadMeta();
                        portInfoGet(currRequest, ref padData);

                        int outIdx = 0;
                        Array.Copy(BitConverter.GetBytes((uint)MessageType.DSUS_PortInfo), 0, outputData, outIdx, 4);
                        outIdx += 4;

                        outputData[outIdx++] = (byte)padData.PadId;
                        outputData[outIdx++] = (byte)padData.PadState;
                        outputData[outIdx++] = (byte)padData.Model;
                        outputData[outIdx++] = (byte)padData.ConnectionType;

                        byte[] addressBytes = null;
                        if (padData.PadMacAddress != null)
                        {
                            addressBytes = padData.PadMacAddress.GetAddressBytes();
                        }

                        if (addressBytes != null && addressBytes.Length == 6)
                        {
                            outputData[outIdx++] = addressBytes[0];
                            outputData[outIdx++] = addressBytes[1];
                            outputData[outIdx++] = addressBytes[2];
                            outputData[outIdx++] = addressBytes[3];
                            outputData[outIdx++] = addressBytes[4];
                            outputData[outIdx++] = addressBytes[5];
                        }
                        else
                        {
                            outputData[outIdx++] = 0;
                            outputData[outIdx++] = 0;
                            outputData[outIdx++] = 0;
                            outputData[outIdx++] = 0;
                            outputData[outIdx++] = 0;
                            outputData[outIdx++] = 0;
                        }

                        outputData[outIdx++] = (byte)padData.BatteryStatus;
                        outputData[outIdx++] = 0;

                        SendPacket(clientEP, outputData, 1001);
                    }
                }
                else if (messageType == (uint)MessageType.DSUC_PadDataReq)
                {
                    byte            regFlags = localMsg[currIdx++];
                    byte            idToReg  = localMsg[currIdx++];
                    PhysicalAddress macToReg = null;
                    {
                        byte[] macBytes = new byte[6];
                        Array.Copy(localMsg, currIdx, macBytes, 0, macBytes.Length);
                        currIdx += macBytes.Length;
                        macToReg = new PhysicalAddress(macBytes);
                    }

                    lock (clients)
                    {
                        if (clients.ContainsKey(clientEP))
                        {
                            clients[clientEP].RequestPadInfo(regFlags, idToReg, macToReg);
                        }
                        else
                        {
                            var clientTimes = new ClientRequestTimes();
                            clientTimes.RequestPadInfo(regFlags, idToReg, macToReg);
                            clients[clientEP] = clientTimes;
                        }
                    }
                }
            }
            catch (Exception e) { }
        }