// Create a command general message.
public int CreateGeneralMessage(bool verified, byte cmd,
ushort receiver, ushort sender, byte flagsRS, byte senderId,
byte dataLen, byte[] pData, byte bufferIndex)
{
if (dataLen > (Manager.MaxPacketSize - ProtocolConstants.GENERAL_OVERHEADS_SIZE))
{
return(-1);
}
int idx = Manager.IoBuffersFreeHeap.Allocate();
if (idx != -1)
{
PacketBuffer b = Manager.IoBuffers[idx];
byte pid = verified ? ProtocolConstants.PID_GENERAL_V : ProtocolConstants.PID_GENERAL;
b.flagsPid = pid;
b.dNetIf = ProtocolConstants.NETIF_UNSET;
b.iNetIf = ProtocolConstants.NETIF_UNSET;
b.pktLen = (byte)(ProtocolConstants.GENERAL_OVERHEADS_SIZE + dataLen);
b.sync(ProtocolConstants.BYTE_SYNC);
b.negPidPid(Primitives.NibbleToPid(pid));
b.destination(LinkMonitor.Destination); // TODO: set destination.
b.arg(0);
b.receiver(receiver);
b.sender(sender);
b.senderId(senderId);
b.flagsRS(flagsRS);
b.command(cmd);
b.dataLength(dataLen);
byte dataIndex = ProtocolConstants.GENERAL_DATA_ARRAY_OFFSET;
byte[] p = b.buffer;
for (byte k = 0; k < dataLen; k++)
{
p[dataIndex++] = pData[bufferIndex + k];
}
b.UpdateCheckSum(b.pktLen);
}
return(idx);
}
// Submit a handshake command to link WriteQ.
// For example, Resend Vno command, ping, reply, etc.
public int SendLinkHandshakePacket(byte pid, ushort destination, byte arg)
{
int idx = Manager.IoBuffersFreeHeap.Allocate();
if (idx != -1)
{
PacketBuffer b = Manager.IoBuffers[idx];
b.flagsPid = pid;
b.dNetIf = ProtocolConstants.NETIF_UNSET;
b.iNetIf = ProtocolConstants.NETIF_UNSET;
b.pktLen = ProtocolConstants.HANDSHAKE_PACKET_SIZE;
b.sync(ProtocolConstants.BYTE_SYNC);
b.negPidPid(Primitives.NibbleToPid(pid));
b.destination(destination);
b.arg(arg);
b.UpdateCheckSum(b.pktLen);
if (IoNetIf.LinkWriteQueue.PushFirst(idx) == -1)
{
Manager.IoBuffersFreeHeap.Release(idx);
return(-1);
}
}
return(idx);
}
public static string DumpHandshake(PacketBuffer b)
{
return("{" + String.Format("pid={0:x2},arg={1:x2}", b.negPidPid() & ProtocolConstants.PID_MASK, b.arg()) + "}\n");
}
// Perform a handshake request received from link.
// Consults original message for r,s details, ports=0, flags=0.
// TODO: check what happens when a master is pinged etc. Ok?
public void PerformLinkHandshake(PacketBuffer hp)
{
int idx;
byte arg = hp.arg();
// TODO: Check packet is for us first.
switch (hp.negPidPid() & ProtocolConstants.PID_MASK)
{
case ProtocolConstants.PID_PING: // We received a ping. Now send a reply.
if (arg >= ProtocolConstants.PID_ARG_BAUD_MIN)
{
switch (arg)
{
case ProtocolConstants.PID_ARG_RESET:
IoNetIf.ResetLinkDriver();
break;
case ProtocolConstants.PID_ARG_SLAVE:
break;
case ProtocolConstants.PID_ARG_MULTI:
break;
case ProtocolConstants.PID_ARG_MASTER:
break;
default: // BAUD: Request to change baud rate.
IoNetIf.IoNetIfDevice.PerformBaudAction(IoNetIf.DeviceContextIndex,
(byte)(arg - ProtocolConstants.PID_ARG_BAUD_MIN),
ProtocolConstants.BAUD_ACTION_SAVE);
break;
}
}
else
{
// Set linkLastInputVno=(VNO_SIZE-1) & linkLastOutputVno=0 ?
CheckOrderMissingQ(arg, false);
IoNetIf.duplexPingReply |= LinkMonitor.DUX_PING_RECEIVED;
}
// Send a reply with Arg = num messages waiting.
// TODO: unless Q contains Msg destined to sender: use "more" msg code.
int num = IoNetIf.LinkWriteQueue.Size(); // Arg = num messages waiting.
SendLinkHandshakePacket(ProtocolConstants.PID_REPLY,
LinkMonitor.Destination, // hp.destination(), // TODO: This should be the linkAdrs.
(byte)((num > 255) ? 255 : num));
break;
case ProtocolConstants.PID_REPLY: //TODO: Now stop pinging.
// arg=number of waiting messages.
// If arg>0 read some messages.
IoNetIf.duplexNumWaiting = arg;
IoNetIf.duplexPingReply |= LinkMonitor.DUX_REPLY_RECEIVED;
break;
case ProtocolConstants.PID_RESEND: // Resend a message.
idx = FindVnoInVerifyQueue(IoNetIf.LinkVerifyQueue, arg);
if (idx == -1)
{
SendLinkHandshakePacket(ProtocolConstants.PID_CANCEL, hp.destination(), arg);
}
else if (IoNetIf.LinkWriteQueue.FindFirstOccurrenceIndex(idx) == -1)
{
PacketBuffer b = Manager.IoBuffers[idx];
b.flagsPid |= ProtocolConstants.META_FLAGS_RESEND;
if (IoNetIf.LinkWriteQueue.PushFirst(idx) == -1)
{
Manager.IoBuffersFreeHeap.Release(idx);
}
}
break;
case ProtocolConstants.PID_CANCEL: // Remove message from missingQ.
IoNetIf.LinkMissingQueue.RemoveFirstOccurrence(arg);
break;
default: break;
}
// TODO: IoNetIf.activityTimeout=Primitives.GetBabelMilliTicker() + LinkMonitor.CONX_ACTIVITY_TIMEOUT;
IoNetIf.baudTimeout = Primitives.GetBabelMilliTicker() + LinkMonitor.BAUD_RATE_TIMEOUT; // Reset timer after input from specific sender.
}
// Called just before message is written to device.
// Determine if packet needs modification.
// Updates DUX & BAUD flags.
// Returns verification action if needed.
// TODO: set destination.
public byte PreLinkWriteFilter(PacketBuffer b)
{
int sumDiff = 0;
byte verifyAction = ProtocolConstants.VERIFY_ACTION_NONE;
byte c = (byte)(b.flagsPid & ProtocolConstants.META_FLAGS_PID);
if (c == ProtocolConstants.PID_GENERAL_V)
{
// Sequence numbers are used to detect bad xfers.
// Resends must be sent with the same Vno rather than a new Vno.
if ((b.flagsPid & ProtocolConstants.META_FLAGS_RESEND) != 0)
{
verifyAction = ProtocolConstants.VERIFY_ACTION_RESEND; // This stops vnoLastOutput being incremented below.
}
else
{
verifyAction = ProtocolConstants.VERIFY_ACTION_NEW;
sumDiff = (int)b.arg() - (int)IoNetIf.vnoLastOutput;
b.arg(IoNetIf.vnoLastOutput);
}
}
else if (c == ProtocolConstants.PID_PING)
{
byte arg = b.arg();
if (arg == 0) // It's a basic ping, so set arg to vno.
{
sumDiff = -(int)IoNetIf.vnoLastOutput;
b.arg(IoNetIf.vnoLastOutput);
}
else if (arg >= ProtocolConstants.PID_ARG_BAUD_MIN)
{
switch (arg)
{
case ProtocolConstants.PID_ARG_RESET:
break;
case ProtocolConstants.PID_ARG_SLAVE:
break;
case ProtocolConstants.PID_ARG_MULTI:
break;
case ProtocolConstants.PID_ARG_MASTER:
break;
default: // BAUD: Flag baud ping sent, set UART_*_SetBaudRate = netIfIndex.
// This is a broadcast to all on link.
IoNetIf.IoNetIfDevice.PerformBaudAction(IoNetIf.DeviceContextIndex,
(byte)(arg - ProtocolConstants.PID_ARG_BAUD_MIN),
ProtocolConstants.BAUD_ACTION_SIGNAL);
IoNetIf.baudTimeout = Primitives.GetBabelMilliTicker() + LinkMonitor.BAUD_RATE_TIMEOUT; // Mark Baud broadcast for all.
break;
}
}
// DUX: need to block further writes.
if ((IoNetIf.duplexKind & (byte)LINK_DUPLEX_KIND.LINK_DUPLEX_KIND_HALF) != 0)
{
IoNetIf.duplexPingReply |= LinkMonitor.DUX_PING_SENT;
IoNetIf.duplexNumWaiting = (byte)0xffu;
IoNetIf.duplexMode = (byte)DUX_MODE.DUX_RX;
}
}
else if (c == ProtocolConstants.PID_REPLY)
{
IoNetIf.duplexPingReply |= LinkMonitor.DUX_REPLY_SENT;// DUX: flag reply sent.
}
// Update checksum: assume valid on entry & work out bit change.
if (sumDiff != 0)
{
// newChkSum = oldChkSum + (oldSumBits - newSumBits).
byte oldChkSum = b.buffer[b.pktLen - 1];
b.buffer[b.pktLen - 1] = (byte)(((int)oldChkSum) + sumDiff);
}
return(verifyAction);
}
