public static Frame CreateACK(byte sequenceNumber, bool pending)
{
var result = new Frame();
result.Length = 5;
result.Type = FrameType.ACK;
result.FramePending = pending;
result.DataSequenceNumber = sequenceNumber;
result.Encode();
return result;
}
private bool ShouldWeAcceptThisFrame(Frame frame)
{
// (1) check if length is ok
// (2) check reserved FCF bits
// for now we assume it is fine - let's be optimistic
// (3) check FCF version
if(frame.FrameVersion > maxFrameVersion.Value)
{
this.Log(LogLevel.Noisy, "Wrong frame version.");
return false;
}
// (4) check source/destination addressing mode
if(frame.SourceAddressingMode == AddressingMode.Reserved || frame.DestinationAddressingMode == AddressingMode.Reserved)
{
this.Log(LogLevel.Noisy, "Wrong addressing mode.");
return false;
}
// (5) check destination address
if(frame.DestinationAddressingMode != AddressingMode.None)
{
// (5.1) check destination PAN
if(frame.AddressInformation.DestinationPan != BroadcastPanIdentifier && frame.AddressInformation.DestinationPan != GetPanId())
{
this.Log(LogLevel.Noisy, "Wrong destination PAN.");
return false;
}
// (5.2) check destination short address
if(frame.DestinationAddressingMode == AddressingMode.ShortAddress)
{
if(!frame.AddressInformation.DestinationAddress.IsShortBroadcast && !frame.AddressInformation.DestinationAddress.Equals(shortAddress))
{
this.Log(LogLevel.Noisy, "Wrong destination short address.");
return false;
}
}
// (5.3) check destination extended address
else if(frame.DestinationAddressingMode == AddressingMode.ExtendedAddress)
{
if(!frame.AddressInformation.DestinationAddress.Equals(extendedAddress))
{
this.Log(LogLevel.Noisy, "Wrong destination extended address (i'm {0}, but the message is directed to {1}.", extendedAddress.GetValue(), frame.AddressInformation.DestinationAddress.GetValue());
return false;
}
}
}
// (6) check frame type
switch(frame.Type)
{
case FrameType.Beacon:
if(!acceptBeaconFrames.Value
|| frame.Length < 9
|| frame.DestinationAddressingMode != AddressingMode.None
|| (frame.SourceAddressingMode != AddressingMode.ShortAddress && frame.SourceAddressingMode != AddressingMode.ExtendedAddress)
|| (frame.AddressInformation.SourcePan != BroadcastPanIdentifier && frame.AddressInformation.SourcePan != GetPanId()))
{
this.Log(LogLevel.Noisy, "Wrong beacon frame.");
return false;
}
break;
case FrameType.Data:
if(!acceptDataFrames.Value
|| frame.Length < 9
|| (frame.DestinationAddressingMode == AddressingMode.None
&& (!isPanCoordinator.Value || frame.AddressInformation.SourcePan != GetPanId())))
{
this.Log(LogLevel.Noisy, "Wrong data frame.");
return false;
}
break;
case FrameType.ACK:
if(!acceptAckFrames.Value || frame.Length != 5)
{
this.Log(LogLevel.Noisy, "Wrong ACK frame.");
return false;
}
break;
case FrameType.MACControl:
if(!acceptMacCmdFrames.Value
|| frame.Length < 9
|| (frame.DestinationAddressingMode == AddressingMode.None
&& (!isPanCoordinator.Value || frame.AddressInformation.SourcePan != GetPanId())))
{
this.Log(LogLevel.Noisy, "Wrong MAC control frame.");
return false;
}
break;
default:
return false;
}
return true;
}
private void SendData()
{
if(txQueue.Count == 0)
{
this.Log(LogLevel.Warning, "Attempted to transmit an empty frame.");
return;
}
irqHandler.RequestInterrupt(InterruptSource.StartOfFrameDelimiter);
var crc = Frame.CalculateCRC(txQueue.Skip(1));
var frame = new Frame(txQueue.Concat(crc).ToArray());
this.DebugLog("Sending frame {0}.", frame.Bytes.Select(x => "0x{0:X}".FormatWith(x)).Stringify());
var frameSent = FrameSent;
if(frameSent != null)
{
frameSent(this, frame.Bytes);
}
irqHandler.RequestInterrupt(InterruptSource.TxDone);
}
public void ReceiveFrame(byte[] bytes)
{
irqHandler.RequestInterrupt(InterruptSource.StartOfFrameDelimiter);
Frame ackFrame = null;
var frame = new Frame(bytes);
var crcOK = frame.CheckCRC();
if(autoCrc.Value && !crcOK)
{
this.Log(LogLevel.Warning, "Received frame with wrong CRC");
}
if(frameFilterEnabled.Value)
{
if(!ShouldWeAcceptThisFrame(frame))
{
this.DebugLog("Not accepting a frame");
return;
}
irqHandler.RequestInterrupt(InterruptSource.FrameAccepted);
}
lock(rxLock)
{
var autoPendingBit = false;
var index = NoSourceIndex;
if(sourceAddressMatchingEnabled.Value && crcOK)
{
switch(frame.SourceAddressingMode)
{
case AddressingMode.ShortAddress:
for(var i = 0u; i < srcShortEnabled.Length; i++)
{
if(!srcShortEnabled[i])
{
continue;
}
if(frame.AddressInformation.SourcePan == GetShortPanIdFromRamTable(i)
&& frame.AddressInformation.SourceAddress.GetValue() == GetShortSourceAddressFromRamTable(i))
{
matchedSourceAddresses[i] = true;
autoPendingBit |= srcShortPendEnabled[i];
if(index == NoSourceIndex)
{
index = i;
}
}
}
break;
case AddressingMode.ExtendedAddress:
for(var i = 0u; i < srcExtendedEnabled.Length; i++)
{
if(!srcExtendedEnabled[i])
{
continue;
}
if(frame.AddressInformation.SourceAddress.GetValue() == GetExtendedSourceAddressFromRamTable(i))
{
matchedSourceAddresses[2 * i] = true;
matchedSourceAddresses[2 * i + 1] = true;
autoPendingBit |= srcExtendedPendEnabled[i];
if(index == NoSourceIndex)
{
index = i | 0x20;
}
}
}
break;
}
matchedSourceIndexField.Value = index;
autoPendingBit &= autoPendEnabled.Value
&& frameFilterEnabled.Value
&& (!pendDataRequestOnly.Value
|| (frame.Type == FrameType.MACControl
&& frame.Payload.Count > 0
&& frame.Payload[0] == 0x4));
BitHelper.SetBit(ref index, 6, autoPendingBit);
if(index != NoSourceIndex)
{
irqHandler.RequestInterrupt(InterruptSource.SrcMatchFound);
}
irqHandler.RequestInterrupt(InterruptSource.SrcMatchDone);
}
if(autoCrc.Value)
{
var rssi = 70; // why 70?
var secondByte = crcOK ? (1u << 7) : 0;
if(appendDataMode.Value)
{
secondByte |= index & 0x7F;
}
else {
secondByte |= 100; // correlation value 100 means near maximum quality
}
frame.Bytes[frame.Bytes.Length - 2] = (byte)rssi;
frame.Bytes[frame.Bytes.Length - 1] = (byte)secondByte;
}
rxQueue.Enqueue(frame);
irqHandler.RequestInterrupt(InterruptSource.FifoP);
if(crcOK && autoAck.Value
&& frame.AcknowledgeRequest
&& frame.Type != FrameType.Beacon
&& frame.Type != FrameType.ACK)
{
ackFrame = Frame.CreateACK(frame.DataSequenceNumber, pendingOr.Value | autoPendingBit);
}
}
var frameSent = FrameSent;
if(frameSent != null && ackFrame != null)
{
frameSent(this, ackFrame.Bytes);
irqHandler.RequestInterrupt(InterruptSource.TxAckDone);
}
irqHandler.RequestInterrupt(InterruptSource.RxPktDone);
}
