1.. SPDX-License-Identifier: GPL-2.0
2
3=========================
4TC queue based filtering
5=========================
6
7TC can be used for directing traffic to either a set of queues or
8to a single queue on both the transmit and receive side.
9
10On the transmit side:
11
121) TC filter directing traffic to a set of queues is achieved
13   using the action skbedit priority for Tx priority selection,
14   the priority maps to a traffic class (set of queues) when
15   the queue-sets are configured using mqprio.
16
172) TC filter directs traffic to a transmit queue with the action
18   skbedit queue_mapping $tx_qid. The action skbedit queue_mapping
19   for transmit queue is executed in software only and cannot be
20   offloaded.
21
22Likewise, on the receive side, the two filters for selecting set of
23queues and/or a single queue are supported as below:
24
251) TC flower filter directs incoming traffic to a set of queues using
26   the 'hw_tc' option.
27   hw_tc $TCID - Specify a hardware traffic class to pass matching
28   packets on to. TCID is in the range 0 through 15.
29
302) TC filter with action skbedit queue_mapping $rx_qid selects a
31   receive queue. The action skbedit queue_mapping for receive queue
32   is supported only in hardware. Multiple filters may compete in
33   the hardware for queue selection. In such case, the hardware
34   pipeline resolves conflicts based on priority. On Intel E810
35   devices, TC filter directing traffic to a queue have higher
36   priority over flow director filter assigning a queue. The hash
37   filter has lowest priority.
38