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hartkopp / can-isotp

Linux Kernel Module for ISO 15765-2:2016 CAN transport protocol PLEASE NOTE: This module is part of the mainline Linux kernel since version 5.10
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candump shows traffic, isotpdump shows traffic, isotprecv does not receive frame #22

Closed brandonros closed 4 years ago

brandonros commented 4 years ago

What data can I provide for you?

$ candump can0
  can0  7E5   [8]  02 10 03 55 55 55 55 55
  can0  7E5   [8]  02 10 03 55 55 55 55 55
  can0  7E5   [8]  02 10 03 55 55 55 55 55
  can0  7E5   [8]  02 10 03 55 55 55 55 55
$ isotpdump -s 7e5 -d 7ed can0
 can0  7E5  [8]  [SF] ln: 2    data: 10 03 55 55 55 55 55 
$ isotprecv -s 7e5 -d 7ed can0

never returns a frame, no matter how many times I resend it (yet it still shows up in isotpdump + candump while isotprecv is running + waiting)

hartkopp commented 4 years ago

This is weird. In fact I started isotpsniffer in parallel which also uses the can-isotp module and it worked!

$ isotpsniffer -s 7e5 -d 7ed vcan0 vcan0 7E5 [2] 10 03 - '..' vcan0 7E5 [2] 10 03 - '..'

I'll take a look at it todays afternoon ...

hartkopp commented 4 years ago

Ah found it! You have to swap (!!) source and destination CAN IDs on isotprecv - as you need to look from the other side of the "virtual point-to-point' channel. So isotprecv -d 7e5 -s 7ed vcan0 makes it :-)