Program Listing for File cemi_frame.cpp
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#include "cemi_frame.h"
#include "bits.h"
#include "string.h"
#include <stdio.h>
/*
cEMI Frame Format
+--------+--------+--------+--------+---------+---------+--------+---------+
| _data |
+--------+--------+--------+--------+---------+---------+--------+---------+
| LPDU |
+--------+--------+--------+--------+---------+---------+--------+---------+
| NPDU |
+---------+--------+--------+--------+--------+---------+---------+--------+---------+
| Header | Msg |Add.Info| Ctrl 1 | Ctrl 2 | Source | Dest. | Data | TPDU |
| | Code | Length | | | Address | Address | Length | APDU |
+---------+--------+--------+--------+--------+---------+---------+--------+---------+
6 bytes 1 byte 1 byte 1 byte 1 byte 2 bytes 2 bytes 1 byte n bytes
Header = See below the structure of a cEMI header
Message Code = See below. On Appendix A is the list of all existing EMI and cEMI codes
Add.Info Length = 0x00 - no additional info
Control Field 1 =
Control Field 2 =
Source Address = 0x0000 - filled in by router/gateway with its source address which is
part of the KNX subnet
Dest. Address = KNX group or individual address (2 byte)
Data Length = Number of bytes of data in the APDU excluding the TPCI/APCI bits
APDU = Application Protocol Data Unit - the actual payload including transport
protocol control information (TPCI), application protocol control
information (APCI) and data passed as an argument from higher layers of
the KNX communication stack
Control Field 1
Bit |
------+---------------------------------------------------------------
7 | Frame Type - 0x0 for extended frame
| 0x1 for standard frame
------+---------------------------------------------------------------
6 | Reserved
|
------+---------------------------------------------------------------
5 | Repeat Flag - 0x0 repeat frame on medium in case of an error
| 0x1 do not repeat
------+---------------------------------------------------------------
4 | System Broadcast - 0x0 system broadcast
| 0x1 broadcast
------+---------------------------------------------------------------
3 | Priority - 0x0 system
| 0x1 normal
------+ 0x2 urgent
2 | 0x3 low
|
------+---------------------------------------------------------------
1 | Acknowledge Request - 0x0 no ACK requested
| (L_Data.req) 0x1 ACK requested
------+---------------------------------------------------------------
0 | Confirm - 0x0 no error
| (L_Data.con) - 0x1 error
------+---------------------------------------------------------------
Control Field 2
Bit |
------+---------------------------------------------------------------
7 | Destination Address Type - 0x0 individual address
| - 0x1 group address
------+---------------------------------------------------------------
6-4 | Hop Count (0-7)
------+---------------------------------------------------------------
3-0 | Extended Frame Format - 0x0 standard frame
------+---------------------------------------------------------------
*/
CemiFrame::CemiFrame(uint8_t* data, uint16_t length)
: _npdu(data + data[1] + NPDU_LPDU_DIFF, *this),
_tpdu(data + data[1] + TPDU_LPDU_DIFF, *this),
_apdu(data + data[1] + APDU_LPDU_DIFF, *this)
{
_data = data;
_ctrl1 = data + data[1] + CEMI_HEADER_SIZE;
_length = length;
}
CemiFrame::CemiFrame(uint8_t apduLength)
: _data(buffer),
_npdu(_data + NPDU_LPDU_DIFF, *this),
_tpdu(_data + TPDU_LPDU_DIFF, *this),
_apdu(_data + APDU_LPDU_DIFF, *this)
{
_ctrl1 = _data + CEMI_HEADER_SIZE;
memset(_data, 0, apduLength + APDU_LPDU_DIFF);
_ctrl1[0] |= Broadcast;
_npdu.octetCount(apduLength);
_length = _npdu.length() + NPDU_LPDU_DIFF;
}
CemiFrame::CemiFrame(const CemiFrame& other)
: _data(buffer),
_npdu(_data + NPDU_LPDU_DIFF, *this),
_tpdu(_data + TPDU_LPDU_DIFF, *this),
_apdu(_data + APDU_LPDU_DIFF, *this)
{
_ctrl1 = _data + CEMI_HEADER_SIZE;
_length = other._length;
memcpy(_data, other._data, other.totalLenght());
}
CemiFrame& CemiFrame::operator=(CemiFrame other)
{
_length = other._length;
_data = buffer;
_ctrl1 = _data + CEMI_HEADER_SIZE;
memcpy(_data, other._data, other.totalLenght());
_npdu._data = _data + NPDU_LPDU_DIFF;
_tpdu._data = _data + TPDU_LPDU_DIFF;
_apdu._data = _data + APDU_LPDU_DIFF;
return *this;
}
MessageCode CemiFrame::messageCode() const
{
return (MessageCode)_data[0];
}
void CemiFrame::messageCode(MessageCode msgCode)
{
_data[0] = msgCode;
}
uint16_t CemiFrame::totalLenght() const
{
return _length;
}
uint16_t CemiFrame::telegramLengthtTP() const
{
if (frameType() == StandardFrame)
return totalLenght() - 2; /*-AddInfo -MsgCode - only one CTRL + CRC, */
else
return totalLenght() - 1; /*-AddInfo -MsgCode + CRC, */
}
void CemiFrame::fillTelegramTP(uint8_t* data)
{
uint16_t len = telegramLengthtTP();
if (frameType() == StandardFrame)
{
uint8_t octet5 = (_ctrl1[1] & 0xF0) | (_ctrl1[6] & 0x0F);
data[0] = _ctrl1[0]; //CTRL
memcpy(data + 1, _ctrl1 + 2, 4); // SA, DA
data[5] = octet5; // LEN; Hopcount, ..
memcpy(data + 6, _ctrl1 + 7, len - 7); // APDU
}
else
{
memcpy(data, _ctrl1, len - 1);
}
data[len - 1] = calcCrcTP(data, len - 1);
}
#ifdef USE_RF
uint16_t CemiFrame::telegramLengthtRF() const
{
return totalLenght() - 3;
}
void CemiFrame::fillTelegramRF(uint8_t* data)
{
uint16_t len = telegramLengthtRF();
// We prepare the actual KNX telegram for RF here only.
// The packaging into blocks with CRC16 (Format based on FT3 Data Link Layer (IEC 870-5))
// is done in the RF Data Link Layer code.
// RF always uses the Extended Frame Format. However, the length field is missing (right before the APDU)
// as there is already a length field at the beginning of the raw RF frame which is also used by the
// physical layer to control the HW packet engine of the transceiver.
data[0] = _ctrl1[1] & 0x0F; // KNX CTRL field for RF (bits 3..0 EFF only), bits 7..4 are set to 0 for asynchronous RF frames
memcpy(data + 1, _ctrl1 + 2, 4); // SA, DA
data[5] = (_ctrl1[1] & 0xF0) | ((_rfLfn & 0x7) << 1) | ((_ctrl1[0] & 0x10) >> 4); // L/NPCI field: AT, Hopcount, LFN, AET
memcpy(data + 6, _ctrl1 + 7, len - 6); // APDU
//printHex("cEMI_fill: ", &data[0], len);
}
#endif
uint8_t* CemiFrame::data()
{
return _data;
}
uint16_t CemiFrame::dataLength()
{
return _length;
}
uint8_t CemiFrame::calcCrcTP(uint8_t* buffer, uint16_t len)
{
uint8_t crc = 0xFF;
for (uint16_t i = 0; i < len; i++)
crc ^= buffer[i];
return crc;
}
FrameFormat CemiFrame::frameType() const
{
return (FrameFormat)(_ctrl1[0] & StandardFrame);
}
void CemiFrame::frameType(FrameFormat type)
{
_ctrl1[0] &= ~StandardFrame;
_ctrl1[0] |= type;
}
Repetition CemiFrame::repetition() const
{
return (Repetition)(_ctrl1[0] & RepetitionAllowed);
}
void CemiFrame::repetition(Repetition rep)
{
_ctrl1[0] &= ~RepetitionAllowed;
_ctrl1[0] |= rep;
}
SystemBroadcast CemiFrame::systemBroadcast() const
{
return (SystemBroadcast)(_ctrl1[0] & Broadcast);
}
void CemiFrame::systemBroadcast(SystemBroadcast value)
{
_ctrl1[0] &= ~Broadcast;
_ctrl1[0] |= value;
}
Priority CemiFrame::priority() const
{
return (Priority)(_ctrl1[0] & LowPriority);
}
void CemiFrame::priority(Priority value)
{
_ctrl1[0] &= ~LowPriority;
_ctrl1[0] |= value;
}
AckType CemiFrame::ack() const
{
return (AckType)(_ctrl1[0] & AckRequested);
}
void CemiFrame::ack(AckType value)
{
_ctrl1[0] &= ~AckRequested;
_ctrl1[0] |= value;
}
Confirm CemiFrame::confirm() const
{
return (Confirm)(_ctrl1[0] & ConfirmError);
}
void CemiFrame::confirm(Confirm value)
{
_ctrl1[0] &= ~ConfirmError;
_ctrl1[0] |= value;
}
AddressType CemiFrame::addressType() const
{
return (AddressType)(_ctrl1[1] & GroupAddress);
}
void CemiFrame::addressType(AddressType value)
{
_ctrl1[1] &= ~GroupAddress;
_ctrl1[1] |= value;
}
uint8_t CemiFrame::hopCount() const
{
return ((_ctrl1[1] >> 4) & 0x7);
}
void CemiFrame::hopCount(uint8_t value)
{
_ctrl1[1] &= ~(0x7 << 4);
_ctrl1[1] |= ((value & 0x7) << 4);
}
uint16_t CemiFrame::sourceAddress() const
{
uint16_t addr;
popWord(addr, _ctrl1 + 2);
return addr;
}
void CemiFrame::sourceAddress(uint16_t value)
{
pushWord(value, _ctrl1 + 2);
}
uint16_t CemiFrame::destinationAddress() const
{
uint16_t addr;
popWord(addr, _ctrl1 + 4);
return addr;
}
void CemiFrame::destinationAddress(uint16_t value)
{
pushWord(value, _ctrl1 + 4);
}
#ifdef USE_RF
uint8_t* CemiFrame::rfSerialOrDoA() const
{
return _rfSerialOrDoA;
}
void CemiFrame::rfSerialOrDoA(const uint8_t* rfSerialOrDoA)
{
_rfSerialOrDoA = (uint8_t*)rfSerialOrDoA;
}
uint8_t CemiFrame::rfInfo() const
{
return _rfInfo;
}
void CemiFrame::rfInfo(uint8_t rfInfo)
{
_rfInfo = rfInfo;
}
uint8_t CemiFrame::rfLfn() const
{
return _rfLfn;
}
void CemiFrame::rfLfn(uint8_t rfLfn)
{
_rfLfn = rfLfn;
}
#endif
NPDU& CemiFrame::npdu()
{
return _npdu;
}
TPDU& CemiFrame::tpdu()
{
return _tpdu;
}
APDU& CemiFrame::apdu()
{
return _apdu;
}
bool CemiFrame::valid() const
{
uint8_t addInfoLen = _data[1];
uint8_t apduLen = _data[_data[1] + NPDU_LPDU_DIFF];
if (_length != 0 && _length != (addInfoLen + apduLen + NPDU_LPDU_DIFF + 2))
{
print("length issue, length: ");
print(_length);
print(" addInfoLen: ");
print(addInfoLen);
print(" apduLen: ");
print(apduLen);
print(" expected length: ");
println(addInfoLen + apduLen + NPDU_LPDU_DIFF + 2);
printHex("Frame: ", _data, _length, true);
return false;
}
if ((_ctrl1[0] & 0x40) > 0 // Bit 6 has do be 0
|| (_ctrl1[1] & 0xF) > 0 // only standard or extended frames
|| _npdu.octetCount() == 0xFF // not allowed
|| (_npdu.octetCount() > 15 && frameType() == StandardFrame)
)
{
print("Other issue");
return false;
}
return true;
}