public const int RESPONSE_CRC = -0x0002; // UInt16BE
// returns the dycrypted response payload only
protected byte[] Decode(MedtronicCnlSession pumpSession, byte[] payload)
{
if (payload.Length < MM_PAYLOAD + NGP_PAYLOAD + NGP55_PAYLOAD + RESPONSE_PAYLOAD ||
payload[MM_COMMAND] == (byte)CommandType.READ_INFO ||
payload[MM_COMMAND] == (byte)CommandType.REQUEST_LINK_KEY_RESPONSE)
{
throw new EncryptionException("Message received for decryption wrong type/size");
}
byte encryptedPayloadSize = payload[MM_PAYLOAD + NGP_PAYLOAD + NGP55_ENCRYPTED_SIZE];
if (encryptedPayloadSize == 0)
{
throw new EncryptionException("Could not decrypt Medtronic Message (encryptedPayloadSize == 0)");
}
var encryptedPayload = new MedtronicMessageBuffer(encryptedPayloadSize);
encryptedPayload.Put(payload, MM_PAYLOAD + NGP_PAYLOAD + NGP55_PAYLOAD, encryptedPayloadSize);
var decryptedPayload = Decrypt(pumpSession.getKey(), pumpSession.getIV(), encryptedPayload);
if (decryptedPayload == null)
{
throw new EncryptionException("Could not decrypt Medtronic Message (decryptedPayload == null)");
}
#if DEBUG
string outputstring = HexDump.DumpHexstring(decryptedPayload);
Log.d(TAG, "DECRYPTED: " + outputstring);
#endif
return(decryptedPayload);
}
protected async Task <byte[]> SendToPump(UsbHidDriver mDevice, MedtronicCnlSession pumpSession, string tag)
{
tag = " (" + tag + ")";
byte[] payload;
byte medtronicSequenceNumber = pumpSession.getMedtronicSequenceNumber();
// extra safety check and delay, CNL is not happy when we miss incoming messages
// the short delay may also help with state readiness
ClearMessage(mDevice, PRESEND_CLEAR_TIMEOUT_MS);
SendMessage(mDevice);
try
{
payload = await ReadMessage_0x81(mDevice);
}
catch (TimeoutException e)
{
// ugh... there should always be a CNL 0x81 response and if we don't get one it usually ends with a E86 / E81 error on the CNL needing a unplug/plug cycle
Log.e(TAG, "Timeout waiting for 0x81 response." + tag);
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new TimeoutException("Timeout waiting for 0x81 response" + tag);
}
Log.d(TAG, "0x81 response: payload.Length=" + payload.Length + (payload.Length >= 0x30 ? " payload[0x21]=" + payload[0x21] + " payload[0x2C]=" + payload[0x2C] + " medtronicSequenceNumber=" + medtronicSequenceNumber + " payload[0x2D]=" + payload[0x2D] : "") + tag);
// following errors usually have no further response from the CNL but occasionally they do
// and these need to be read and cleared asap or yep E86 me baby and a unresponsive CNL
// the extra delay from the clearMessage timeout may be helping here too by holding back any further downstream sends etc - investigate
if (payload.Length <= 0x21)
{
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new UnexpectedMessageException("0x81 response was empty" + tag); // *bad* CNL death soon after this, may want to end comms immediately
}
else if (payload.Length != 0x30 && payload[0x21] != 0x55)
{
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new UnexpectedMessageException("0x81 response was not a 0x55 message" + tag);
}
else if (payload[0x2C] != medtronicSequenceNumber)
{
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new UnexpectedMessageException("0x81 sequence number does not match" + tag);
}
else if (payload[0x2D] == 0x04)
{
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new UnexpectedMessageException("0x81 connection busy" + tag);
}
else if (payload[0x2D] != 0x02)
{
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
throw new UnexpectedMessageException("0x81 connection lost" + tag);
}
return(payload);
}
public AckMessage(MedtronicCnlSession pumpSession, object p)
{
this.pumpSession = pumpSession;
this.p = p;
}
protected async Task <byte[]> ReadFromPump(UsbHidDriver mDevice, MedtronicCnlSession pumpSession, string tag)
{
tag = " (" + tag + ")";
MultipacketSession multipacketSession = null;
byte[] tupple;
byte[] payload = null;
byte[] decrypted = null;
bool fetchMoreData = true;
int retry = 0;
int expectedSegments = 0;
int cmd;
while (fetchMoreData)
{
if (multipacketSession != null)
{
do
{
if (expectedSegments < 1)
{
tupple = multipacketSession.MissingSegments();
new MultipacketResendPacketsMessage(pumpSession, tupple).send(mDevice);
expectedSegments = read16BEtoUInt(tupple, 0x02);
}
try
{
payload = await ReadMessage(mDevice, MULTIPACKET_TIMEOUT_MS);
break;
}
catch (TimeoutException e)
{
if (++retry >= SEGMENT_RETRY)
{
throw new TimeoutException("Timeout waiting for response from pump (multipacket)" + tag);
}
Log.d(TAG, "*** Multisession timeout, expecting:" + expectedSegments + " retry: " + retry);
expectedSegments = 0;
}
} while (retry > 0);
}
else
{
try
{
payload = await ReadMessage(mDevice, READ_TIMEOUT_MS);
}
catch (TimeoutException e)
{
throw new TimeoutException("Timeout waiting for response from pump" + tag);
}
}
if (payload.Length < 0x0039)
{
Log.d(TAG, "*** bad response" + HexDump.DumpHexstring(payload, 0x12, payload.Length - 0x14));
fetchMoreData = true;
}
else
{
decrypted = Decode(pumpSession, payload);
cmd = read16BEtoUInt(decrypted, RESPONSE_COMMAND);
Log.d(TAG, "CMD: " + HexDump.ToHexstring(cmd));
if (MedtronicSendMessageRequestMessage.MessageType.EHSM_SESSION.response(cmd))
{
// EHSM_SESSION(0)
Log.d(TAG, "*** EHSM response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = true;
}
else if (MedtronicSendMessageRequestMessage.MessageType.NAK_COMMAND.response(cmd))
{
Log.d(TAG, "*** NAK response" + HexDump.DumpHexstring(decrypted));
ClearMessage(mDevice, ERROR_CLEAR_TIMEOUT_MS);
// if multipacket was in progress we may need to clear 2 EHSM_SESSION(1) messages from pump
short nakcmd = read16BEtoShort(decrypted, 3);
byte nakcode = decrypted[5];
throw new UnexpectedMessageException("Pump sent a NAK(" + string.Format("%02X", nakcmd) + ":" + string.Format("%02X", nakcode) + ") response" + tag);
}
else if (MedtronicSendMessageRequestMessage.MessageType.INITIATE_MULTIPACKET_TRANSFER.response(cmd))
{
multipacketSession = new MultipacketSession(decrypted);
new AckMessage(pumpSession, MedtronicSendMessageRequestMessage.MessageType.INITIATE_MULTIPACKET_TRANSFER.response()).send(mDevice);
expectedSegments = multipacketSession.PacketsToFetch;
fetchMoreData = true;
}
else if (MedtronicSendMessageRequestMessage.MessageType.MULTIPACKET_SEGMENT_TRANSMISSION.response(cmd))
{
if (multipacketSession == null)
{
throw new UnexpectedMessageException("multipacketSession not initiated before segment received" + tag);
}
multipacketSession.AddSegment(decrypted);
expectedSegments--;
if (multipacketSession.PayloadComplete)
{
Log.d(TAG, "*** Multisession Complete");
new AckMessage(pumpSession, MedtronicSendMessageRequestMessage.MessageType.MULTIPACKET_SEGMENT_TRANSMISSION.response()).send(mDevice);
// read 0412 = EHSM_SESSION(1)
payload = await ReadMessage(mDevice, READ_TIMEOUT_MS);
decrypted = Decode(pumpSession, payload);
Log.d(TAG, "*** response" + HexDump.DumpHexstring(decrypted));
return(multipacketSession.Response);
}
else
{
fetchMoreData = true;
}
}
else if (MedtronicSendMessageRequestMessage.MessageType.END_HISTORY_TRANSMISSION.response(cmd))
{
Log.d(TAG, "*** END_HISTORY_TRANSMISSION response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_PUMP_TIME.response(cmd))
{
Log.d(TAG, "*** READ_PUMP_TIME response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_PUMP_STATUS.response(cmd))
{
Log.d(TAG, "*** READ_PUMP_STATUS response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_HISTORY_INFO.response(cmd))
{
Log.d(TAG, "*** READ_HISTORY_INFO response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_BASAL_PATTERN.response(cmd))
{
Log.d(TAG, "*** READ_BASAL_PATTERN response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_BOLUS_WIZARD_CARB_RATIOS.response(cmd))
{
Log.d(TAG, "*** READ_BOLUS_WIZARD_CARB_RATIOS response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_BOLUS_WIZARD_SENSITIVITY_FACTORS.response(cmd))
{
Log.d(TAG, "*** READ_BOLUS_WIZARD_SENSITIVITY_FACTORS response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else if (MedtronicSendMessageRequestMessage.MessageType.READ_BOLUS_WIZARD_BG_TARGETS.response(cmd))
{
Log.d(TAG, "*** READ_BOLUS_WIZARD_BG_TARGETS response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = false;
}
else
{
Log.d(TAG, "*** ??? response" + HexDump.DumpHexstring(decrypted));
fetchMoreData = true;
}
}
}
// when returning non-multipacket decrypted data, we need to trim the 2 byte checksum
if (decrypted == null)
{
return(payload);
}
return(decrypted.Partial(0, decrypted.Length - 2));
}
public MultipacketResendPacketsMessage(MedtronicCnlSession pumpSession, byte[] tupple)
{
this.pumpSession = pumpSession;
this.tupple = tupple;
}