1 # SPDX-License-Identifier: GPL-2.0-only
3 # Traffic control configuration.
7 bool "QoS and/or fair queueing"
10 When the kernel has several packets to send out over a network
11 device, it has to decide which ones to send first, which ones to
12 delay, and which ones to drop. This is the job of the queueing
13 disciplines, several different algorithms for how to do this
14 "fairly" have been proposed.
16 If you say N here, you will get the standard packet scheduler, which
17 is a FIFO (first come, first served). If you say Y here, you will be
18 able to choose from among several alternative algorithms which can
19 then be attached to different network devices. This is useful for
20 example if some of your network devices are real time devices that
21 need a certain minimum data flow rate, or if you need to limit the
22 maximum data flow rate for traffic which matches specified criteria.
23 This code is considered to be experimental.
25 To administer these schedulers, you'll need the user-level utilities
26 from the package iproute2+tc at
27 <https://www.kernel.org/pub/linux/utils/net/iproute2/>. That package
28 also contains some documentation; for more, check out
29 <http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2>.
31 This Quality of Service (QoS) support will enable you to use
32 Differentiated Services (diffserv) and Resource Reservation Protocol
33 (RSVP) on your Linux router if you also say Y to the corresponding
34 classifiers below. Documentation and software is at
35 <http://diffserv.sourceforge.net/>.
37 If you say Y here and to "/proc file system" below, you will be able
38 to read status information about packet schedulers from the file
41 The available schedulers are listed in the following questions; you
42 can say Y to as many as you like. If unsure, say N now.
46 comment "Queueing/Scheduling"
49 tristate "Hierarchical Token Bucket (HTB)"
51 Say Y here if you want to use the Hierarchical Token Buckets (HTB)
52 packet scheduling algorithm. See
53 <http://luxik.cdi.cz/~devik/qos/htb/> for complete manual and
56 HTB is very similar to CBQ regarding its goals however is has
57 different properties and different algorithm.
59 To compile this code as a module, choose M here: the
60 module will be called sch_htb.
63 tristate "Hierarchical Fair Service Curve (HFSC)"
65 Say Y here if you want to use the Hierarchical Fair Service Curve
66 (HFSC) packet scheduling algorithm.
68 To compile this code as a module, choose M here: the
69 module will be called sch_hfsc.
72 tristate "Multi Band Priority Queueing (PRIO)"
74 Say Y here if you want to use an n-band priority queue packet
77 To compile this code as a module, choose M here: the
78 module will be called sch_prio.
81 tristate "Hardware Multiqueue-aware Multi Band Queuing (MULTIQ)"
83 Say Y here if you want to use an n-band queue packet scheduler
84 to support devices that have multiple hardware transmit queues.
86 To compile this code as a module, choose M here: the
87 module will be called sch_multiq.
90 tristate "Random Early Detection (RED)"
92 Say Y here if you want to use the Random Early Detection (RED)
93 packet scheduling algorithm.
95 See the top of <file:net/sched/sch_red.c> for more details.
97 To compile this code as a module, choose M here: the
98 module will be called sch_red.
101 tristate "Stochastic Fair Blue (SFB)"
103 Say Y here if you want to use the Stochastic Fair Blue (SFB)
104 packet scheduling algorithm.
106 See the top of <file:net/sched/sch_sfb.c> for more details.
108 To compile this code as a module, choose M here: the
109 module will be called sch_sfb.
112 tristate "Stochastic Fairness Queueing (SFQ)"
114 Say Y here if you want to use the Stochastic Fairness Queueing (SFQ)
115 packet scheduling algorithm.
117 See the top of <file:net/sched/sch_sfq.c> for more details.
119 To compile this code as a module, choose M here: the
120 module will be called sch_sfq.
123 tristate "True Link Equalizer (TEQL)"
125 Say Y here if you want to use the True Link Equalizer (TLE) packet
126 scheduling algorithm. This queueing discipline allows the combination
127 of several physical devices into one virtual device.
129 See the top of <file:net/sched/sch_teql.c> for more details.
131 To compile this code as a module, choose M here: the
132 module will be called sch_teql.
135 tristate "Token Bucket Filter (TBF)"
137 Say Y here if you want to use the Token Bucket Filter (TBF) packet
138 scheduling algorithm.
140 See the top of <file:net/sched/sch_tbf.c> for more details.
142 To compile this code as a module, choose M here: the
143 module will be called sch_tbf.
146 tristate "Credit Based Shaper (CBS)"
148 Say Y here if you want to use the Credit Based Shaper (CBS) packet
149 scheduling algorithm.
151 See the top of <file:net/sched/sch_cbs.c> for more details.
153 To compile this code as a module, choose M here: the
154 module will be called sch_cbs.
157 tristate "Earliest TxTime First (ETF)"
159 Say Y here if you want to use the Earliest TxTime First (ETF) packet
160 scheduling algorithm.
162 See the top of <file:net/sched/sch_etf.c> for more details.
164 To compile this code as a module, choose M here: the
165 module will be called sch_etf.
167 config NET_SCH_MQPRIO_LIB
170 Common library for manipulating mqprio queue configurations.
172 config NET_SCH_TAPRIO
173 tristate "Time Aware Priority (taprio) Scheduler"
174 select NET_SCH_MQPRIO_LIB
176 Say Y here if you want to use the Time Aware Priority (taprio) packet
177 scheduling algorithm.
179 See the top of <file:net/sched/sch_taprio.c> for more details.
181 To compile this code as a module, choose M here: the
182 module will be called sch_taprio.
185 tristate "Generic Random Early Detection (GRED)"
187 Say Y here if you want to use the Generic Random Early Detection
188 (GRED) packet scheduling algorithm for some of your network devices
189 (see the top of <file:net/sched/sch_red.c> for details and
190 references about the algorithm).
192 To compile this code as a module, choose M here: the
193 module will be called sch_gred.
196 tristate "Network emulator (NETEM)"
198 Say Y if you want to emulate network delay, loss, and packet
199 re-ordering. This is often useful to simulate networks when
200 testing applications or protocols.
202 To compile this driver as a module, choose M here: the module
203 will be called sch_netem.
208 tristate "Deficit Round Robin scheduler (DRR)"
210 Say Y here if you want to use the Deficit Round Robin (DRR) packet
211 scheduling algorithm.
213 To compile this driver as a module, choose M here: the module
214 will be called sch_drr.
218 config NET_SCH_MQPRIO
219 tristate "Multi-queue priority scheduler (MQPRIO)"
220 select NET_SCH_MQPRIO_LIB
222 Say Y here if you want to use the Multi-queue Priority scheduler.
223 This scheduler allows QOS to be offloaded on NICs that have support
224 for offloading QOS schedulers.
226 To compile this driver as a module, choose M here: the module will
227 be called sch_mqprio.
231 config NET_SCH_SKBPRIO
232 tristate "SKB priority queue scheduler (SKBPRIO)"
234 Say Y here if you want to use the SKB priority queue
235 scheduler. This schedules packets according to skb->priority,
236 which is useful for request packets in DoS mitigation systems such
239 To compile this driver as a module, choose M here: the module will
240 be called sch_skbprio.
245 tristate "CHOose and Keep responsive flow scheduler (CHOKE)"
247 Say Y here if you want to use the CHOKe packet scheduler (CHOose
248 and Keep for responsive flows, CHOose and Kill for unresponsive
249 flows). This is a variation of RED which tries to penalize flows
250 that monopolize the queue.
252 To compile this code as a module, choose M here: the
253 module will be called sch_choke.
256 tristate "Quick Fair Queueing scheduler (QFQ)"
258 Say Y here if you want to use the Quick Fair Queueing Scheduler (QFQ)
259 packet scheduling algorithm.
261 To compile this driver as a module, choose M here: the module
262 will be called sch_qfq.
267 tristate "Controlled Delay AQM (CODEL)"
269 Say Y here if you want to use the Controlled Delay (CODEL)
270 packet scheduling algorithm.
272 To compile this driver as a module, choose M here: the module
273 will be called sch_codel.
277 config NET_SCH_FQ_CODEL
278 tristate "Fair Queue Controlled Delay AQM (FQ_CODEL)"
280 Say Y here if you want to use the FQ Controlled Delay (FQ_CODEL)
281 packet scheduling algorithm.
283 To compile this driver as a module, choose M here: the module
284 will be called sch_fq_codel.
289 tristate "Common Applications Kept Enhanced (CAKE)"
291 Say Y here if you want to use the Common Applications Kept Enhanced
292 (CAKE) queue management algorithm.
294 To compile this driver as a module, choose M here: the module
295 will be called sch_cake.
300 tristate "Fair Queue"
302 Say Y here if you want to use the FQ packet scheduling algorithm.
304 FQ does flow separation, and is able to respect pacing requirements
305 set by TCP stack into sk->sk_pacing_rate (for locally generated
308 To compile this driver as a module, choose M here: the module
309 will be called sch_fq.
314 tristate "Heavy-Hitter Filter (HHF)"
316 Say Y here if you want to use the Heavy-Hitter Filter (HHF)
317 packet scheduling algorithm.
319 To compile this driver as a module, choose M here: the module
320 will be called sch_hhf.
323 tristate "Proportional Integral controller Enhanced (PIE) scheduler"
325 Say Y here if you want to use the Proportional Integral controller
326 Enhanced scheduler packet scheduling algorithm.
327 For more information, please see https://tools.ietf.org/html/rfc8033
329 To compile this driver as a module, choose M here: the module
330 will be called sch_pie.
334 config NET_SCH_FQ_PIE
335 depends on NET_SCH_PIE
336 tristate "Flow Queue Proportional Integral controller Enhanced (FQ-PIE)"
338 Say Y here if you want to use the Flow Queue Proportional Integral
339 controller Enhanced (FQ-PIE) packet scheduling algorithm.
340 For more information, please see https://tools.ietf.org/html/rfc8033
342 To compile this driver as a module, choose M here: the module
343 will be called sch_fq_pie.
347 config NET_SCH_INGRESS
348 tristate "Ingress/classifier-action Qdisc"
349 depends on NET_CLS_ACT
352 Say Y here if you want to use classifiers for incoming and/or outgoing
353 packets. This qdisc doesn't do anything else besides running classifiers,
354 which can also have actions attached to them. In case of outgoing packets,
355 classifiers that this qdisc holds are executed in the transmit path
356 before real enqueuing to an egress qdisc happens.
360 To compile this code as a module, choose M here: the module will be
361 called sch_ingress with alias of sch_clsact.
364 tristate "Plug network traffic until release (PLUG)"
367 This queuing discipline allows userspace to plug/unplug a network
368 output queue, using the netlink interface. When it receives an
369 enqueue command it inserts a plug into the outbound queue that
370 causes following packets to enqueue until a dequeue command arrives
371 over netlink, causing the plug to be removed and resuming the normal
374 This module also provides a generic "network output buffering"
375 functionality (aka output commit), wherein upon arrival of a dequeue
376 command, only packets up to the first plug are released for delivery.
377 The Remus HA project uses this module to enable speculative execution
378 of virtual machines by allowing the generated network output to be rolled
381 For more information, please refer to <http://wiki.xenproject.org/wiki/Remus>
383 Say Y here if you are using this kernel for Xen dom0 and
384 want to protect Xen guests with Remus.
386 To compile this code as a module, choose M here: the
387 module will be called sch_plug.
390 tristate "Enhanced transmission selection scheduler (ETS)"
392 The Enhanced Transmission Selection scheduler is a classful
393 queuing discipline that merges functionality of PRIO and DRR
394 qdiscs in one scheduler. ETS makes it easy to configure a set of
395 strict and bandwidth-sharing bands to implement the transmission
396 selection described in 802.1Qaz.
398 Say Y here if you want to use the ETS packet scheduling
401 To compile this driver as a module, choose M here: the module
402 will be called sch_ets.
406 menuconfig NET_SCH_DEFAULT
407 bool "Allow override default queue discipline"
409 Support for selection of default queuing discipline.
411 Nearly all users can safely say no here, and the default
412 of pfifo_fast will be used. Many distributions already set
413 the default value via /proc/sys/net/core/default_qdisc.
420 prompt "Default queuing discipline"
421 default DEFAULT_PFIFO_FAST
423 Select the queueing discipline that will be used by default
424 for all network devices.
427 bool "Fair Queue" if NET_SCH_FQ
430 bool "Controlled Delay" if NET_SCH_CODEL
432 config DEFAULT_FQ_CODEL
433 bool "Fair Queue Controlled Delay" if NET_SCH_FQ_CODEL
435 config DEFAULT_FQ_PIE
436 bool "Flow Queue Proportional Integral controller Enhanced" if NET_SCH_FQ_PIE
439 bool "Stochastic Fair Queue" if NET_SCH_SFQ
441 config DEFAULT_PFIFO_FAST
442 bool "Priority FIFO Fast"
445 config DEFAULT_NET_SCH
447 default "pfifo_fast" if DEFAULT_PFIFO_FAST
448 default "fq" if DEFAULT_FQ
449 default "fq_codel" if DEFAULT_FQ_CODEL
450 default "fq_pie" if DEFAULT_FQ_PIE
451 default "sfq" if DEFAULT_SFQ
455 comment "Classification"
461 tristate "Elementary classification (BASIC)"
464 Say Y here if you want to be able to classify packets using
465 only extended matches and actions.
467 To compile this code as a module, choose M here: the
468 module will be called cls_basic.
470 config NET_CLS_ROUTE4
471 tristate "Routing decision (ROUTE)"
473 select IP_ROUTE_CLASSID
476 If you say Y here, you will be able to classify packets
477 according to the route table entry they matched.
479 To compile this code as a module, choose M here: the
480 module will be called cls_route.
483 tristate "Netfilter mark (FW)"
486 If you say Y here, you will be able to classify packets
487 according to netfilter/firewall marks.
489 To compile this code as a module, choose M here: the
490 module will be called cls_fw.
493 tristate "Universal 32bit comparisons w/ hashing (U32)"
496 Say Y here to be able to classify packets using a universal
497 32bit pieces based comparison scheme.
499 To compile this code as a module, choose M here: the
500 module will be called cls_u32.
503 bool "Performance counters support"
504 depends on NET_CLS_U32
506 Say Y here to make u32 gather additional statistics useful for
507 fine tuning u32 classifiers.
510 bool "Netfilter marks support"
511 depends on NET_CLS_U32
513 Say Y here to be able to use netfilter marks as u32 key.
516 tristate "Flow classifier"
519 If you say Y here, you will be able to classify packets based on
520 a configurable combination of packet keys. This is mostly useful
521 in combination with SFQ.
523 To compile this code as a module, choose M here: the
524 module will be called cls_flow.
526 config NET_CLS_CGROUP
527 tristate "Control Group Classifier"
529 select CGROUP_NET_CLASSID
532 Say Y here if you want to classify packets based on the control
533 cgroup of their process.
535 To compile this code as a module, choose M here: the
536 module will be called cls_cgroup.
539 tristate "BPF-based classifier"
542 If you say Y here, you will be able to classify packets based on
543 programmable BPF (JIT'ed) filters as an alternative to ematches.
545 To compile this code as a module, choose M here: the module will
548 config NET_CLS_FLOWER
549 tristate "Flower classifier"
552 If you say Y here, you will be able to classify packets based on
553 a configurable combination of packet keys and masks.
555 To compile this code as a module, choose M here: the module will
556 be called cls_flower.
558 config NET_CLS_MATCHALL
559 tristate "Match-all classifier"
562 If you say Y here, you will be able to classify packets based on
563 nothing. Every packet will match.
565 To compile this code as a module, choose M here: the module will
566 be called cls_matchall.
569 bool "Extended Matches"
572 Say Y here if you want to use extended matches on top of classifiers
573 and select the extended matches below.
575 Extended matches are small classification helpers not worth writing
576 a separate classifier for.
578 A recent version of the iproute2 package is required to use
581 config NET_EMATCH_STACK
583 depends on NET_EMATCH
586 Size of the local stack variable used while evaluating the tree of
587 ematches. Limits the depth of the tree, i.e. the number of
588 encapsulated precedences. Every level requires 4 bytes of additional
591 config NET_EMATCH_CMP
592 tristate "Simple packet data comparison"
593 depends on NET_EMATCH
595 Say Y here if you want to be able to classify packets based on
596 simple packet data comparisons for 8, 16, and 32bit values.
598 To compile this code as a module, choose M here: the
599 module will be called em_cmp.
601 config NET_EMATCH_NBYTE
602 tristate "Multi byte comparison"
603 depends on NET_EMATCH
605 Say Y here if you want to be able to classify packets based on
606 multiple byte comparisons mainly useful for IPv6 address comparisons.
608 To compile this code as a module, choose M here: the
609 module will be called em_nbyte.
611 config NET_EMATCH_U32
613 depends on NET_EMATCH
615 Say Y here if you want to be able to classify packets using
616 the famous u32 key in combination with logic relations.
618 To compile this code as a module, choose M here: the
619 module will be called em_u32.
621 config NET_EMATCH_META
623 depends on NET_EMATCH
625 Say Y here if you want to be able to classify packets based on
626 metadata such as load average, netfilter attributes, socket
627 attributes and routing decisions.
629 To compile this code as a module, choose M here: the
630 module will be called em_meta.
632 config NET_EMATCH_TEXT
633 tristate "Textsearch"
634 depends on NET_EMATCH
636 select TEXTSEARCH_KMP
638 select TEXTSEARCH_FSM
640 Say Y here if you want to be able to classify packets based on
641 textsearch comparisons.
643 To compile this code as a module, choose M here: the
644 module will be called em_text.
646 config NET_EMATCH_CANID
647 tristate "CAN Identifier"
648 depends on NET_EMATCH && (CAN=y || CAN=m)
650 Say Y here if you want to be able to classify CAN frames based
653 To compile this code as a module, choose M here: the
654 module will be called em_canid.
656 config NET_EMATCH_IPSET
658 depends on NET_EMATCH && IP_SET
660 Say Y here if you want to be able to classify packets based on
663 To compile this code as a module, choose M here: the
664 module will be called em_ipset.
666 config NET_EMATCH_IPT
667 tristate "IPtables Matches"
668 depends on NET_EMATCH && NETFILTER && NETFILTER_XTABLES
670 Say Y here to be able to classify packets based on iptables
672 Current supported match is "policy" which allows packet classification
673 based on IPsec policy that was used during decapsulation
675 To compile this code as a module, choose M here: the
676 module will be called em_ipt.
683 Say Y here if you want to use traffic control actions. Actions
684 get attached to classifiers and are invoked after a successful
685 classification. They are used to overwrite the classification
686 result, instantly drop or redirect packets, etc.
688 A recent version of the iproute2 package is required to use
691 config NET_ACT_POLICE
692 tristate "Traffic Policing"
693 depends on NET_CLS_ACT
695 Say Y here if you want to do traffic policing, i.e. strict
696 bandwidth limiting. This action replaces the existing policing
699 To compile this code as a module, choose M here: the
700 module will be called act_police.
703 tristate "Generic actions"
704 depends on NET_CLS_ACT
706 Say Y here to take generic actions such as dropping and
709 To compile this code as a module, choose M here: the
710 module will be called act_gact.
713 bool "Probability support"
714 depends on NET_ACT_GACT
716 Say Y here to use the generic action randomly or deterministically.
718 config NET_ACT_MIRRED
719 tristate "Redirecting and Mirroring"
720 depends on NET_CLS_ACT
722 Say Y here to allow packets to be mirrored or redirected to
725 To compile this code as a module, choose M here: the
726 module will be called act_mirred.
728 config NET_ACT_SAMPLE
729 tristate "Traffic Sampling"
730 depends on NET_CLS_ACT
733 Say Y here to allow packet sampling tc action. The packet sample
734 action consists of statistically choosing packets and sampling
735 them using the psample module.
737 To compile this code as a module, choose M here: the
738 module will be called act_sample.
741 tristate "Stateless NAT"
742 depends on NET_CLS_ACT
744 Say Y here to do stateless NAT on IPv4 packets. You should use
745 netfilter for NAT unless you know what you are doing.
747 To compile this code as a module, choose M here: the
748 module will be called act_nat.
751 tristate "Packet Editing"
752 depends on NET_CLS_ACT
754 Say Y here if you want to mangle the content of packets.
756 To compile this code as a module, choose M here: the
757 module will be called act_pedit.
760 tristate "Simple Example (Debug)"
761 depends on NET_CLS_ACT
763 Say Y here to add a simple action for demonstration purposes.
764 It is meant as an example and for debugging purposes. It will
765 print a configured policy string followed by the packet count
766 to the console for every packet that passes by.
770 To compile this code as a module, choose M here: the
771 module will be called act_simple.
773 config NET_ACT_SKBEDIT
774 tristate "SKB Editing"
775 depends on NET_CLS_ACT
777 Say Y here to change skb priority or queue_mapping settings.
781 To compile this code as a module, choose M here: the
782 module will be called act_skbedit.
785 tristate "Checksum Updating"
786 depends on NET_CLS_ACT && INET
789 Say Y here to update some common checksum after some direct
792 To compile this code as a module, choose M here: the
793 module will be called act_csum.
796 tristate "MPLS manipulation"
797 depends on NET_CLS_ACT
799 Say Y here to push or pop MPLS headers.
803 To compile this code as a module, choose M here: the
804 module will be called act_mpls.
807 tristate "Vlan manipulation"
808 depends on NET_CLS_ACT
810 Say Y here to push or pop vlan headers.
814 To compile this code as a module, choose M here: the
815 module will be called act_vlan.
818 tristate "BPF based action"
819 depends on NET_CLS_ACT
821 Say Y here to execute BPF code on packets. The BPF code will decide
822 if the packet should be dropped or not.
826 To compile this code as a module, choose M here: the
827 module will be called act_bpf.
829 config NET_ACT_CONNMARK
830 tristate "Netfilter Connection Mark Retriever"
831 depends on NET_CLS_ACT && NETFILTER
832 depends on NF_CONNTRACK && NF_CONNTRACK_MARK
834 Say Y here to allow retrieving of conn mark
838 To compile this code as a module, choose M here: the
839 module will be called act_connmark.
841 config NET_ACT_CTINFO
842 tristate "Netfilter Connection Mark Actions"
843 depends on NET_CLS_ACT && NETFILTER
844 depends on NF_CONNTRACK && NF_CONNTRACK_MARK
846 Say Y here to allow transfer of a connmark stored information.
847 Current actions transfer connmark stored DSCP into
848 ipv4/v6 diffserv and/or to transfer connmark to packet
849 mark. Both are useful for restoring egress based marks
850 back onto ingress connections for qdisc priority mapping
855 To compile this code as a module, choose M here: the
856 module will be called act_ctinfo.
858 config NET_ACT_SKBMOD
859 tristate "skb data modification action"
860 depends on NET_CLS_ACT
862 Say Y here to allow modification of skb data
866 To compile this code as a module, choose M here: the
867 module will be called act_skbmod.
870 tristate "Inter-FE action based on IETF ForCES InterFE LFB"
871 depends on NET_CLS_ACT
874 Say Y here to allow for sourcing and terminating metadata
875 For details refer to netdev01 paper:
876 "Distributing Linux Traffic Control Classifier-Action Subsystem"
877 Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
879 To compile this code as a module, choose M here: the
880 module will be called act_ife.
882 config NET_ACT_TUNNEL_KEY
883 tristate "IP tunnel metadata manipulation"
884 depends on NET_CLS_ACT
886 Say Y here to set/release ip tunnel metadata.
890 To compile this code as a module, choose M here: the
891 module will be called act_tunnel_key.
894 tristate "connection tracking tc action"
895 depends on NET_CLS_ACT && NF_CONNTRACK && (!NF_NAT || NF_NAT) && NF_FLOW_TABLE
896 select NF_CONNTRACK_OVS
897 select NF_NAT_OVS if NF_NAT
899 Say Y here to allow sending the packets to conntrack module.
903 To compile this code as a module, choose M here: the
904 module will be called act_ct.
907 tristate "Frame gate entry list control tc action"
908 depends on NET_CLS_ACT
910 Say Y here to allow to control the ingress flow to be passed at
911 specific time slot and be dropped at other specific time slot by
915 To compile this code as a module, choose M here: the
916 module will be called act_gate.
918 config NET_IFE_SKBMARK
919 tristate "Support to encoding decoding skb mark on IFE action"
920 depends on NET_ACT_IFE
922 config NET_IFE_SKBPRIO
923 tristate "Support to encoding decoding skb prio on IFE action"
924 depends on NET_ACT_IFE
926 config NET_IFE_SKBTCINDEX
927 tristate "Support to encoding decoding skb tcindex on IFE action"
928 depends on NET_ACT_IFE
930 config NET_TC_SKB_EXT
931 bool "TC recirculation support"
932 depends on NET_CLS_ACT
933 select SKB_EXTENSIONS
936 Say Y here to allow tc chain misses to continue in OvS datapath in
937 the correct recirc_id, and hardware chain misses to continue in
938 the correct chain in tc software datapath.
940 Say N here if you won't be using tc<->ovs offload or tc chains offload.