PRU example project to read ethernet frame

Andrea,

Could you use promiscuous mode (or tcpdump) and standard Ethernet to capture the network traffic, reverse engineer the frames in the regular arm cores and then decide what protocols is active in the network? Or why do you need to try to do this in the PRU level.

  Pekka

Hi Pekka,

i really don't need to make it in PRU level but i was thinking to follow what you did in AM335 device [TIDEP0032 code example].

Just a question : don't i need the PRU for the Ethercat protocotol?

Yes for EtherCAT or EtherNet/IP or PROFINET you'll need a protocol specific firmware and software stack. Each of these protocols has a different firmware, they cannot exist in parallel in the program memory of the ICSS.

My understanding of what you are trying to do:

1. Snoop traffic on the Ethernet wire to try to reverse engineer what industrial protocol is being used in the LAN. Building blocks to achieve this are capturing raw Ethernet frames, look at EtherType for PROFINET and EtherCAT, then go deeper into the packets for EtherNet/IP. This is your code, there is no standard or general specification how this can be done. One possibility is Ethernet in promiscuous mode or for example tcpdump with ICSS running standard Ethernet. We had the old demo on AM335x doing this in PRU, but there is no advantage in detecting the protocol on PRU or Arm core.

2. Make the decisions of what protocol is used

3. Load and restart the ICSS with the protocol detected

4. ICSS runs the protocol specific firmware from TI, and R5 runs the software stack (TI industrial comms toolkit, or 3rd party)

  Pekka

Adding on to Pekka's response:

We do provide basic resources for general purpose PRU programming (e.g., latest AM64x documentation at https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/08_02_00_17/exports/docs/linux/Foundational_Components_PRU-ICSS_PRU_ICSSG.html ). We will continue adding some additional resources, like this new set of Getting Started labs that we document beginning in SDK 8.3 (AM62x docs: https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/08_03_00_19/exports/docs/common/PRU-ICSS/PRU-Getting-Started-Labs.html ).

However, PRU networking firmware is very complex, and we cannot support questions about writing or modifying PRU networking firmware on the forums. If specific protocols or software stacks are needed, we can help connect you with the right resources either within TI, or with a 3rd party developer.

Regards,

Nick

Hi Pekka, is there a code example which implements TCPDUMP?

Maybe worthwhile step would be to capture network traffic using tcpdump and analyze using wireshark https://www.wireshark.org/docs/wsug_html_chunked/AppToolstcpdump.html . Wireshark documentation includes example captures for industrial protocols like EtherCAT https://wiki.wireshark.org/Protocols/ethercat .

The full manual pages for tcpdump are at https://www.tcpdump.org/manpages/tcpdump.1.html .

  Pekka

Hi Pekka,

thank you so much for your answer but i've already made it of course.

What i was trying to ask you [probably my request was not so clear] was if there's a code example to understand how to initialize and manage AM64x [R5F core] to try to capture and analyze ethernet frames [i've not found in the SDK code examples that analyze or print the received ethernet frames to terminal] just to understand which SDK drivers i have to use to make it.

Andrea,

For a demo I would suggest to use Linux and the available extensive tools for this. Use Linux as standard Ethernet, scan the traffic on the wire to attempt to decide what industrial protocol is being used, then reboot the R5 with the appropriate stack and ICSS firmware. I do want to remind as I stated before there is no general case or standard that will guarantee that detecting what industrial network is used, so a demo is clearly possible, but there will be maybe corner cases that will be hard to cover. If you try to replicate the Linux tools or the subset of functionality in R5 freeRTOS, they are of course available in source code.

On R5 freeRTOS the base example of Ethernet layer 2 functionality is:

https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/latest/exports/docs/api_guide_am64x/EXAMPLES_ENET_LAYER2_ICSSG.html 

to enable promiscuous mode (you are trying to reverse engineer traffic meant for other devices in the LAN) looks like there is an API:

https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/latest/exports/docs/api_guide_am64x/group__NETWORKING__ICSS__EMAC__MODULE.html#gaa99712fc609fb0a9bf7a11eb4d854336 

Modify the example to start getting all the frames in the LAN using this, and add your logic of deciding what this traffic means from the perspective of the active industrial protocol in the LAN.

  Pekka

The thread has been unlocked.

-Nick