PTP(Precision Time Protocol) message is silently DROPPED by CNI plugin bridge

[wt2017]

Issue:

• In IEEE Std 1588™-2019, 01-80-C2-00-00-0E multicast address is defined for multicast (ITU-T G.8275.1 profile) scenario.
• In CNI plugin bridge, packet with 01-80-C2-00-00-0E is silently dropped since it locates in MAC address range for LLDP.
• In kernel bridge implementation, echo 16384 > /sys/class/net/<bridge_name>/bridge/group_fwd_mask is provided to change the default (silent drop) behavior to normally (MAC based) forward.
• But this option provided by kernel can't be set into CNI, due to NO configuration parameter for it.

Can CNI plugin - bridge, add one additional parameter group_fwd_mask, to activate the bridge function which is already provided in kernel ?

[champtar]

@wt2017 you can use an udev rule on the host:

ACTION=="add|change", SUBSYSTEM=="net", KERNEL=="<bridge_name>", RUN+="/bin/sh -c 'echo 16384 > /sys/class/net/<bridge_name>/bridge/group_fwd_mask'"