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Linux/AM3359: EtherNet/IP issues

HS FAE Germany
Mastermind 32460 points

Part Number: AM3359
Other Parts Discussed in Thread: TMDSICE3359

Tool/software: Linux

Hello,
my customer set up a virtual box with Ubuntu. The Molex stack is running on our TMDSICE3359 with Linux Image on SDHC. He can communicate with the stack and read the “list identity” through UDP with the Molex EIP test tool. Then He send TCP messages and gets following message:
„[ 1593.174255] TCP: request_sock_TCP: Possible SYN flooding on port 44818. Dropping request.  Check SNMP counters.“
The iptables are empty.

He tries the follwing:
-          Rule in iptables for TCP port 44818 configured:
iptables -I INPUT 1 -p tcp --dport 44818 -j ACCEPT
-          sysctl -w net.ipv4.tcp_synack_retries=50000
-          sysctl -w net.ipv4.tcp_syn_retries=50000
-          tcp_syncookies couldn’t be set – may be it is disabled in the Kernel

The behaviour is the same.

Why and where will be TCP 44818 dropped?#
What should be changed so that TCP is running.

Conifugration:
- Ethernet interface: They use the physical RJ45 close to the PCB edge which maps to eth0 in Linux.
- Protocol: There is TI Linux image on SDHC taken from this link:
http://software-dl.ti.com/processor-sdk-linux-rt/esd/AM335X/latest/index_FDS.html
EIP stack with adaptation for Linux is taken from Molex as such – nothing modified. There are no further TI components.
- Ethernet/IP master: EIP-Tool from Molex is running on Win10 PC – firewall, antivirus etc. is disabled.
TCP is transmitted by the PC NIC, but EVb doesn´t reply/acknowledge (wireshark/tcpdump captures  are attached).
- UDP is working well, but TCP causes the following message on the EVB:
„[ 1593.174255] TCP: request_sock_TCP: Possible SYN flooding on port 44818. Dropping request.  Check SNMP counters.“
- PRU-ICSS EIP with TI RTOS is working fine.
- IP configured in the EIP tool (running on Win10 PC): 128.127.58.135
- Static IP on the PC´s NIC is 128.127.58.112
- Commands executed in the Linux console:
ifconfig eth0 128.127.58.135 netmask 255.255.255.0
ping 128.127.58.112 -c3
echo "r" "t" | ./eip_adapter okl
tcpdump -nnvXSs 0 -c10 -w /etc/tcpdump.pcap

Regards, Holger

  • 0
    TI__Mastermind 40580 points
    Hi Holger, could you please attach wireshark/tcpdumb captures?
    thank you!
    Paula
  • 0 in reply to Paula Carrillo
    TI__Mastermind 40750 points
    Hi,

    As a quick test to see if I could access port 44818 I ran iperf specifying the TCP port on a AM335x eth0 (cpsw) GPEVM and the test succeeded:

    gpevm : iperf -s -p 44818
    Ubuntu pc: iperf -c <ip address of gpevm> -p 44818

    I did not setup an ip table rule to get this to work. I also did not see anything out of the ordinary on a quick scan of the wireshark capture. This was a quick test on an existing setup that I have, it is using a pre-built SDK.

    For the moment I think the issue is in the Molex stack which is not something we can support at TI. But I would like to offer that the customer try this test first before concluding that the Molex stack is the issue.

    Since the AM335x ICE board was used there are some jumpers that have to setup. Since ping and UDP work but not TCP is interesting. Please try the above test without the Molex stack running.

    Please attach a picture of the jumper setting that are around the Ethernet Connector, also please attach (not paste) the boot log captured on the console. Also please do not compress the attached boot log.

    Best Regards,
    Schuyler