packet dump between vpcd and vicc.

[12019]

Hi,
the following was capture by wireshark and do "follow tcp stream".

    00000000  00 01                                            ..
    00000002  04                                               .
00000000  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....  <<< ATR sent by vicc.
    00000003  00 01                                            ..
    00000005  04                                               .
0000000D  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....
    00000006  00 01                                            ..
    00000008  01 00 01 04                                      ....                <<<< what does this means?
0000001A  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....
    0000000C  00 01                                            ..
    0000000E  04                                               .
00000027  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....
    0000000F  00 01                                            ..
    00000011  00 00 01 04                                      ....  <<<<< and this one.
00000034  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....
    00000015  00 01                                            ..
    00000017  04                                               .
00000041  00 0b 3b 95 13 81 01 80  73 ff 01 00 0b          ..;..... s....

default reader.conf in /etc/reader.conf

FRIENDLYNAME "Virtual PCD"
DEVICENAME /dev/null:0x8C7B
LIBPATH /usr/lib/pcsc/drivers/serial/libifdvpcd.so
CHANNELID 0x8C7B

and vicc command line
./vicc -H 192.168.0.12 -vvvv -t iso7816
As wiki mentioned
https://frankmorgner.github.io/vsmartcard/virtualsmartcard/api.html

0x0 0x01 0x04 as Get ATR from vicc.

so am not sure what happend there on vpcd to sends out " 0x01 0x00 0x01 0x04"

thanks
BL.

[12019]

by the way why vpcd sends out so many "GET ATR" packet? is it used for "keep alive"?

[frankmorgner]

00000006  00 01                                            ..
    00000008  01 00 01 04                                      ....                <<<< what does this means?

Above you can actually see two commands

1. 00 01 01
2. 00 01 04

[frankmorgner]

Yes, we use the "get atr" command to check if the connection is still alive. Unfortunately there is no other way of checking than actually transferring data, as far as i know.

I thought about improving network performance, e.g. by using UDP or by introducing a real NOOP. But I never experienced any problem with the current setup, so I think I leave it as is.