Re: [PATCH net-next v2 3/6] net: bridge: add 802.1Qat stream reservation admission control

On 6 Jun 2026, at 6:21 pm, Nikolay Aleksandrov [off-list ref] wrote:

On 06/06/2026 11:02, Luke Howard wrote:

quoted

The definition of Dynamic Reservation Entries in 802.1Q (clause 8.8.7) might support the addition of a new MDB (or even FDB) entry state to the kernel:
- add MDB_DYNAMIC_RESERVATION (a state, not a flag);
- the software bridge only _classifies_ packets against  MDB_DYNAMIC_RESERVATION entries, and only when MDB is authoritative. Classification sets dynamic_reservation_hit on tc_skb_ext;
- dynamic_reservation_hit is visible to the flow dissector so can be used for policy enforcement.

See, saying the bridge has to classify doesn't sound right. Why not do the
classification where such operations are usually done, e.g. tc?
You have to manually designate these entries anyway.

s/classify/mark, i.e. marking a forwarding bit for tc to match, a la l2_miss.

tc can’t see into the MDB to tell if a DA has a dynamic reservation entry so, without an explicit DRE bit, the SRP daemon would need to maintain a flower permit filter per DRE. Not needing this allows the user to set a single policy filter prior to starting SRP, e.g.:

tc filter add dev lan0 egress protocol 802.1Q pref 1 handle 1 flower vlan_prio 3 dynamic_reservation_hit 0 action drop

It also maps cleanly to chips that support 802.1Qav with priority regeneration or filtering, but which can’t support tc-flower.