The code was used as early debug code to read different files from
the SIM card and therefore acquire the IMSI, and other SIM card
specific information.
This only was useful for testing that the firmware worked properly.
Is is not needed for regular use cases.
The commands "cmd1", "cmd2", "cmd_poweron", "cmd_poweroff",
"cmd_get_slot_stat", "cmd_get_param" where early test commands,
but have not been used as such in moths.
A programmer, who wants to send commands to the smartcard, should
use the functions of ccid_raw.py (e.g. send_receive_cmd) instead.
With the python module scapy the headers of each layer have to be created
by hand. Furthermore, in order to use it, the program would have to be
started as root.
Using sockets would be the better. The reason for using scapy was, that
it was the first best thing that I found when searching for python
socket communication.
The next step would be to open and close the socket only once instead
of every time an APDU is send to wireshark.
Furthermore, the ATR probably has to be treated differently from APDU packets.
The data type of incoming and outgoing data should be the same
at all points of the program to make it consistent.
For this program the data type is array.array.
Wait time extension commands are not implemented yet.
They are a nice-to-have for the future, since they would enable
the board to work with phones that expect a higher frequency.
With a wait time extension request towards the phone, SIMtrace could
signal the phone to wait for a longer time period while SIMtrace is
still waiting for a response from the SIM card.
Atmel library mixes up the value for two different messages.
Explanation can be found here:
http://permalink.gmane.org/gmane.comp.mobile.osmocom.simtrace/29
Actually, a better fix for this problem would be to go through the
Atmel code and replace ICC_INSERTED_EVENT with ICC_BS_PRESENT_NOTACTIVATED
where appropriate and in accordance with the Smart Card CCID standard
(and libccid, for this matter).
The code used a vendor and product id taken from Atmel example code.
Now it is changed to the vendor and product id, which was also previously
used in the original SIMtrace code.
Since the host side does the parsing of the packets, (not the firmware,
as it was in the old simtrace version), we do not need to check for expired
max waiting time.
Instead, every byte received from the phone is filled into a ring buffer.
As soon as the USB endpoint to the host is not busy anymore, it is sent
to the host over the respective USB endpoint.
The define PR was introduced to switch quickly between TRACE levels
for specific debug print messages.
Now, it all became debug output, since it is not needed in normal
operation.
Christina Quast