PROCESSOR-SDK-AM335X: Race condition on Ethernet startup

Mathew Maher49

Expert 2085 points

Hi!

I've got a meta-custom layer implemented over arago-base-tisdk-image. One of the customisations is a re-implementation of ifupdown (copied and modified from meta-ti).

The layer seems to work well: putting a customised /etc/network/interfaces file onto the target correctly.

However, there seems to be a race condition on startup. None of the interfaces file customisations are loaded upon boot. Instead, a manual ifup/ifdown command is needed to bring them into play, i.e.:

root@am335x-evm:~# ifconfig
eth0      Link encap:Ethernet  HWaddr F4:E1:1E:AD:C7:9D
          inet6 addr: fe80::f6e1:1eff:fead:c79d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:94 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:19058 (18.6 KiB)
          Interrupt:45

root@am335x-evm:~# ifdown eth0
ifdown: interface eth0 not configured
root@am335x-evm:~# ifup eth0
root@am335x-evm:~# ifconfig
eth0      Link encap:Ethernet  HWaddr F4:E1:1E:AD:C7:9D
          inet addr:192.168.5.1  Bcast:192.168.5.255  Mask:255.255.255.0
          inet6 addr: fe80::f6e1:1eff:fead:c79d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1 errors:0 dropped:0 overruns:0 frame:0
          TX packets:111 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:101 (101.0 B)  TX bytes:22710 (22.1 KiB)
          Interrupt:45


(Note the sudden appearance of a static IP address) 

The guts of the interface customisation is just this:

# Wired or wireless interfaces
allow-hotplug eth0
iface eth0 inet static
        address 192.168.5.1
        netmask 255.255.255.0

allow-hotplug eth1
iface eth1 inet static
        address 192.168.5.255
        netmask 255.255.255.0

Anyone any ideas what might be causing this and how to correct?

Mat

over 4 years ago

0 Biser Gatchev-XID over 4 years ago

TI__Guru**** 393215 points

Please post which kernel version is this.

0 Mathew Maher49 over 4 years ago in reply to Biser Gatchev-XID

Expert 2085 points

4.19.79-rt28-g5baf382c8f

Processor SDK 06.02.00.81

0 Schuyler Patton over 4 years ago in reply to Mathew Maher49

TI__Mastermind 34815 points

Hi,

I want to clarify what you need first. Do you want the static IP addresses on boot up without having to the ifup/down cycliing?

Best Regards,

Schuyler

0 Mathew Maher49 over 4 years ago in reply to Schuyler Patton

Expert 2085 points

yes: the device will be running headless, so I need the ethernet fully active upon bootup otherwise I have no other means of connecting to it.

thanks

Mat

0 Schuyler Patton over 4 years ago in reply to Mathew Maher49

TI__Mastermind 34815 points

Hi,

Hopefully I understand what you are asking. The system initialization daemon SystemD performs the network interface initialization somewhat differently that sysVinit. The previous sysVinit system initialization relied up /etc/interfaces file, SystemD does not completely.

Please try this, create this file in this directory /etc/systemd/network/01-eth-static.network with the contents below. I think I filled it out to match your setup. Hopefully this does away with the down/up sequence you have to do.

---- File contents -----
[Match]
Name=eth0

[Network]
Address=192.168.5.1
----- EOF -----------

Best Regards,

Schuyler

0 Mathew Maher49 over 4 years ago in reply to Schuyler Patton

Expert 2085 points

Bang on!

Thanks: solved the problem in one!

0 Mathew Maher49 over 4 years ago in reply to Mathew Maher49

Expert 2085 points

Just in case anyone needs it, this can be auto-configured in the yocto build by:

- create a systemd receipe in your custom layer as a .bbappend

- add a files folder with the relevant systemd files in (multiple files for multiple networks)

- create systemd_%.bbappend with the following:

FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

SRC_URI += "     file://01-eth-static.network     file://02-usb-static.network     file://03-can0.network     file://04-can1.network "

FILES_${PN} += "${systemd_unitdir}/network/*"

do_install_append() {
     install -d ${D}${systemd_unitdir}/network/
     install -m 0644 ${WORKDIR}/*.network ${D}${systemd_unitdir}/network/

}

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PROCESSOR-SDK-AM335X: Race condition on Ethernet startup