Technical Details: Switchdev Mode and TC-Flower

TC-Flower enables implementing another data path in the Linux kernel using the TC subsystem through which the flow rules can be offloaded to hardware. The TC-Flower Classifier, along with TC actions infrastructure, is used to implement the TC data path. It can be configured by OVS or any control plane as a software implementation and/or a way to offload to hardware. The data path can be configured as one or more tables that can hold match/action flow rules.

Each flow rule can match on a set of well-known packet field’s metadata and perform the actions redirect and drop.

• Only one action per flow is supported (the last one in the list), though the driver can parse the action list.
• All TC Match fields have equal priority.
• Drop action has higher precedence than redirect action.