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1# SPDX-License-Identifier: GPL-2.0-only
2#
3# IP configuration
4#
5config IP_MULTICAST
6 bool "IP: multicasting"
7 help
8 This is code for addressing several networked computers at once,
9 enlarging your kernel by about 2 KB. You need multicasting if you
10 intend to participate in the MBONE, a high bandwidth network on top
11 of the Internet which carries audio and video broadcasts. More
12 information about the MBONE is on the WWW at
13 <https://www.savetz.com/mbone/>. For most people, it's safe to say N.
14
15config IP_ADVANCED_ROUTER
16 bool "IP: advanced router"
17 help
18 If you intend to run your Linux box mostly as a router, i.e. as a
19 computer that forwards and redistributes network packets, say Y; you
20 will then be presented with several options that allow more precise
21 control about the routing process.
22
23 The answer to this question won't directly affect the kernel:
24 answering N will just cause the configurator to skip all the
25 questions about advanced routing.
26
27 Note that your box can only act as a router if you enable IP
28 forwarding in your kernel; you can do that by saying Y to "/proc
29 file system support" and "Sysctl support" below and executing the
30 line
31
32 echo "1" > /proc/sys/net/ipv4/ip_forward
33
34 at boot time after the /proc file system has been mounted.
35
36 If you turn on IP forwarding, you should consider the rp_filter, which
37 automatically rejects incoming packets if the routing table entry
38 for their source address doesn't match the network interface they're
39 arriving on. This has security advantages because it prevents the
40 so-called IP spoofing, however it can pose problems if you use
41 asymmetric routing (packets from you to a host take a different path
42 than packets from that host to you) or if you operate a non-routing
43 host which has several IP addresses on different interfaces. To turn
44 rp_filter on use:
45
46 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
47 or
48 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
49
50 Note that some distributions enable it in startup scripts.
51 For details about rp_filter strict and loose mode read
52 <file:Documentation/networking/ip-sysctl.rst>.
53
54 If unsure, say N here.
55
56config IP_FIB_TRIE_STATS
57 bool "FIB TRIE statistics"
58 depends on IP_ADVANCED_ROUTER
59 help
60 Keep track of statistics on structure of FIB TRIE table.
61 Useful for testing and measuring TRIE performance.
62
63config IP_MULTIPLE_TABLES
64 bool "IP: policy routing"
65 depends on IP_ADVANCED_ROUTER
66 select FIB_RULES
67 help
68 Normally, a router decides what to do with a received packet based
69 solely on the packet's final destination address. If you say Y here,
70 the Linux router will also be able to take the packet's source
71 address into account. Furthermore, the TOS (Type-Of-Service) field
72 of the packet can be used for routing decisions as well.
73
74 If you need more information, see the Linux Advanced
75 Routing and Traffic Control documentation at
76 <https://lartc.org/howto/lartc.rpdb.html>
77
78 If unsure, say N.
79
80config IP_ROUTE_MULTIPATH
81 bool "IP: equal cost multipath"
82 depends on IP_ADVANCED_ROUTER
83 help
84 Normally, the routing tables specify a single action to be taken in
85 a deterministic manner for a given packet. If you say Y here
86 however, it becomes possible to attach several actions to a packet
87 pattern, in effect specifying several alternative paths to travel
88 for those packets. The router considers all these paths to be of
89 equal "cost" and chooses one of them in a non-deterministic fashion
90 if a matching packet arrives.
91
92config IP_ROUTE_VERBOSE
93 bool "IP: verbose route monitoring"
94 depends on IP_ADVANCED_ROUTER
95 help
96 If you say Y here, which is recommended, then the kernel will print
97 verbose messages regarding the routing, for example warnings about
98 received packets which look strange and could be evidence of an
99 attack or a misconfigured system somewhere. The information is
100 handled by the klogd daemon which is responsible for kernel messages
101 ("man klogd").
102
103config IP_ROUTE_CLASSID
104 bool
105
106config IP_PNP
107 bool "IP: kernel level autoconfiguration"
108 help
109 This enables automatic configuration of IP addresses of devices and
110 of the routing table during kernel boot, based on either information
111 supplied on the kernel command line or by BOOTP or RARP protocols.
112 You need to say Y only for diskless machines requiring network
113 access to boot (in which case you want to say Y to "Root file system
114 on NFS" as well), because all other machines configure the network
115 in their startup scripts.
116
117config IP_PNP_DHCP
118 bool "IP: DHCP support"
119 depends on IP_PNP
120 help
121 If you want your Linux box to mount its whole root file system (the
122 one containing the directory /) from some other computer over the
123 net via NFS and you want the IP address of your computer to be
124 discovered automatically at boot time using the DHCP protocol (a
125 special protocol designed for doing this job), say Y here. In case
126 the boot ROM of your network card was designed for booting Linux and
127 does DHCP itself, providing all necessary information on the kernel
128 command line, you can say N here.
129
130 If unsure, say Y. Note that if you want to use DHCP, a DHCP server
131 must be operating on your network. Read
132 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
133
134config IP_PNP_BOOTP
135 bool "IP: BOOTP support"
136 depends on IP_PNP
137 help
138 If you want your Linux box to mount its whole root file system (the
139 one containing the directory /) from some other computer over the
140 net via NFS and you want the IP address of your computer to be
141 discovered automatically at boot time using the BOOTP protocol (a
142 special protocol designed for doing this job), say Y here. In case
143 the boot ROM of your network card was designed for booting Linux and
144 does BOOTP itself, providing all necessary information on the kernel
145 command line, you can say N here. If unsure, say Y. Note that if you
146 want to use BOOTP, a BOOTP server must be operating on your network.
147 Read <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
148
149config IP_PNP_RARP
150 bool "IP: RARP support"
151 depends on IP_PNP
152 help
153 If you want your Linux box to mount its whole root file system (the
154 one containing the directory /) from some other computer over the
155 net via NFS and you want the IP address of your computer to be
156 discovered automatically at boot time using the RARP protocol (an
157 older protocol which is being obsoleted by BOOTP and DHCP), say Y
158 here. Note that if you want to use RARP, a RARP server must be
159 operating on your network. Read
160 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
161
162config NET_IPIP
163 tristate "IP: tunneling"
164 select INET_TUNNEL
165 select NET_IP_TUNNEL
166 help
167 Tunneling means encapsulating data of one protocol type within
168 another protocol and sending it over a channel that understands the
169 encapsulating protocol. This particular tunneling driver implements
170 encapsulation of IP within IP, which sounds kind of pointless, but
171 can be useful if you want to make your (or some other) machine
172 appear on a different network than it physically is, or to use
173 mobile-IP facilities (allowing laptops to seamlessly move between
174 networks without changing their IP addresses).
175
176 Saying Y to this option will produce two modules ( = code which can
177 be inserted in and removed from the running kernel whenever you
178 want). Most people won't need this and can say N.
179
180config NET_IPGRE_DEMUX
181 tristate "IP: GRE demultiplexer"
182 help
183 This is helper module to demultiplex GRE packets on GRE version field criteria.
184 Required by ip_gre and pptp modules.
185
186config NET_IP_TUNNEL
187 tristate
188 select DST_CACHE
189 select GRO_CELLS
190 default n
191
192config NET_IPGRE
193 tristate "IP: GRE tunnels over IP"
194 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
195 select NET_IP_TUNNEL
196 help
197 Tunneling means encapsulating data of one protocol type within
198 another protocol and sending it over a channel that understands the
199 encapsulating protocol. This particular tunneling driver implements
200 GRE (Generic Routing Encapsulation) and at this time allows
201 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
202 This driver is useful if the other endpoint is a Cisco router: Cisco
203 likes GRE much better than the other Linux tunneling driver ("IP
204 tunneling" above). In addition, GRE allows multicast redistribution
205 through the tunnel.
206
207config NET_IPGRE_BROADCAST
208 bool "IP: broadcast GRE over IP"
209 depends on IP_MULTICAST && NET_IPGRE
210 help
211 One application of GRE/IP is to construct a broadcast WAN (Wide Area
212 Network), which looks like a normal Ethernet LAN (Local Area
213 Network), but can be distributed all over the Internet. If you want
214 to do that, say Y here and to "IP multicast routing" below.
215
216config IP_MROUTE_COMMON
217 bool
218 depends on IP_MROUTE || IPV6_MROUTE
219
220config IP_MROUTE
221 bool "IP: multicast routing"
222 depends on IP_MULTICAST
223 select IP_MROUTE_COMMON
224 help
225 This is used if you want your machine to act as a router for IP
226 packets that have several destination addresses. It is needed on the
227 MBONE, a high bandwidth network on top of the Internet which carries
228 audio and video broadcasts. In order to do that, you would most
229 likely run the program mrouted. If you haven't heard about it, you
230 don't need it.
231
232config IP_MROUTE_MULTIPLE_TABLES
233 bool "IP: multicast policy routing"
234 depends on IP_MROUTE && IP_ADVANCED_ROUTER
235 select FIB_RULES
236 help
237 Normally, a multicast router runs a userspace daemon and decides
238 what to do with a multicast packet based on the source and
239 destination addresses. If you say Y here, the multicast router
240 will also be able to take interfaces and packet marks into
241 account and run multiple instances of userspace daemons
242 simultaneously, each one handling a single table.
243
244 If unsure, say N.
245
246config IP_PIMSM_V1
247 bool "IP: PIM-SM version 1 support"
248 depends on IP_MROUTE
249 help
250 Kernel side support for Sparse Mode PIM (Protocol Independent
251 Multicast) version 1. This multicast routing protocol is used widely
252 because Cisco supports it. You need special software to use it
253 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
254 information about PIM.
255
256 Say Y if you want to use PIM-SM v1. Note that you can say N here if
257 you just want to use Dense Mode PIM.
258
259config IP_PIMSM_V2
260 bool "IP: PIM-SM version 2 support"
261 depends on IP_MROUTE
262 help
263 Kernel side support for Sparse Mode PIM version 2. In order to use
264 this, you need an experimental routing daemon supporting it (pimd or
265 gated-5). This routing protocol is not used widely, so say N unless
266 you want to play with it.
267
268config SYN_COOKIES
269 bool "IP: TCP syncookie support"
270 help
271 Normal TCP/IP networking is open to an attack known as "SYN
272 flooding". This denial-of-service attack prevents legitimate remote
273 users from being able to connect to your computer during an ongoing
274 attack and requires very little work from the attacker, who can
275 operate from anywhere on the Internet.
276
277 SYN cookies provide protection against this type of attack. If you
278 say Y here, the TCP/IP stack will use a cryptographic challenge
279 protocol known as "SYN cookies" to enable legitimate users to
280 continue to connect, even when your machine is under attack. There
281 is no need for the legitimate users to change their TCP/IP software;
282 SYN cookies work transparently to them. For technical information
283 about SYN cookies, check out <https://cr.yp.to/syncookies.html>.
284
285 If you are SYN flooded, the source address reported by the kernel is
286 likely to have been forged by the attacker; it is only reported as
287 an aid in tracing the packets to their actual source and should not
288 be taken as absolute truth.
289
290 SYN cookies may prevent correct error reporting on clients when the
291 server is really overloaded. If this happens frequently better turn
292 them off.
293
294 If you say Y here, you can disable SYN cookies at run time by
295 saying Y to "/proc file system support" and
296 "Sysctl support" below and executing the command
297
298 echo 0 > /proc/sys/net/ipv4/tcp_syncookies
299
300 after the /proc file system has been mounted.
301
302 If unsure, say N.
303
304config NET_IPVTI
305 tristate "Virtual (secure) IP: tunneling"
306 depends on IPV6 || IPV6=n
307 select INET_TUNNEL
308 select NET_IP_TUNNEL
309 select XFRM
310 help
311 Tunneling means encapsulating data of one protocol type within
312 another protocol and sending it over a channel that understands the
313 encapsulating protocol. This can be used with xfrm mode tunnel to give
314 the notion of a secure tunnel for IPSEC and then use routing protocol
315 on top.
316
317config NET_UDP_TUNNEL
318 tristate
319 select NET_IP_TUNNEL
320 default n
321
322config NET_FOU
323 tristate "IP: Foo (IP protocols) over UDP"
324 select NET_UDP_TUNNEL
325 help
326 Foo over UDP allows any IP protocol to be directly encapsulated
327 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
328 network mechanisms and optimizations for UDP (such as ECMP
329 and RSS) can be leveraged to provide better service.
330
331config NET_FOU_IP_TUNNELS
332 bool "IP: FOU encapsulation of IP tunnels"
333 depends on NET_IPIP || NET_IPGRE || IPV6_SIT
334 select NET_FOU
335 help
336 Allow configuration of FOU or GUE encapsulation for IP tunnels.
337 When this option is enabled IP tunnels can be configured to use
338 FOU or GUE encapsulation.
339
340config INET_AH
341 tristate "IP: AH transformation"
342 select XFRM_AH
343 help
344 Support for IPsec AH (Authentication Header).
345
346 AH can be used with various authentication algorithms. Besides
347 enabling AH support itself, this option enables the generic
348 implementations of the algorithms that RFC 8221 lists as MUST be
349 implemented. If you need any other algorithms, you'll need to enable
350 them in the crypto API. You should also enable accelerated
351 implementations of any needed algorithms when available.
352
353 If unsure, say Y.
354
355config INET_ESP
356 tristate "IP: ESP transformation"
357 select XFRM_ESP
358 help
359 Support for IPsec ESP (Encapsulating Security Payload).
360
361 ESP can be used with various encryption and authentication algorithms.
362 Besides enabling ESP support itself, this option enables the generic
363 implementations of the algorithms that RFC 8221 lists as MUST be
364 implemented. If you need any other algorithms, you'll need to enable
365 them in the crypto API. You should also enable accelerated
366 implementations of any needed algorithms when available.
367
368 If unsure, say Y.
369
370config INET_ESP_OFFLOAD
371 tristate "IP: ESP transformation offload"
372 depends on INET_ESP
373 select XFRM_OFFLOAD
374 default n
375 help
376 Support for ESP transformation offload. This makes sense
377 only if this system really does IPsec and want to do it
378 with high throughput. A typical desktop system does not
379 need it, even if it does IPsec.
380
381 If unsure, say N.
382
383config INET_ESPINTCP
384 bool "IP: ESP in TCP encapsulation (RFC 8229)"
385 depends on XFRM && INET_ESP
386 select STREAM_PARSER
387 select NET_SOCK_MSG
388 select XFRM_ESPINTCP
389 help
390 Support for RFC 8229 encapsulation of ESP and IKE over
391 TCP/IPv4 sockets.
392
393 If unsure, say N.
394
395config INET_IPCOMP
396 tristate "IP: IPComp transformation"
397 select INET_XFRM_TUNNEL
398 select XFRM_IPCOMP
399 help
400 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
401 typically needed for IPsec.
402
403 If unsure, say Y.
404
405config INET_TABLE_PERTURB_ORDER
406 int "INET: Source port perturbation table size (as power of 2)" if EXPERT
407 default 16
408 help
409 Source port perturbation table size (as power of 2) for
410 RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm.
411
412 The default is almost always what you want.
413 Only change this if you know what you are doing.
414
415config INET_XFRM_TUNNEL
416 tristate
417 select INET_TUNNEL
418 default n
419
420config INET_TUNNEL
421 tristate
422 default n
423
424config INET_DIAG
425 tristate "INET: socket monitoring interface"
426 default y
427 help
428 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
429 native Linux tools such as ss. ss is included in iproute2, currently
430 downloadable at:
431
432 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
433
434 If unsure, say Y.
435
436config INET_TCP_DIAG
437 depends on INET_DIAG
438 def_tristate INET_DIAG
439
440config INET_UDP_DIAG
441 tristate "UDP: socket monitoring interface"
442 depends on INET_DIAG && (IPV6 || IPV6=n)
443 default n
444 help
445 Support for UDP socket monitoring interface used by the ss tool.
446 If unsure, say Y.
447
448config INET_RAW_DIAG
449 tristate "RAW: socket monitoring interface"
450 depends on INET_DIAG && (IPV6 || IPV6=n)
451 default n
452 help
453 Support for RAW socket monitoring interface used by the ss tool.
454 If unsure, say Y.
455
456config INET_DIAG_DESTROY
457 bool "INET: allow privileged process to administratively close sockets"
458 depends on INET_DIAG
459 default n
460 help
461 Provides a SOCK_DESTROY operation that allows privileged processes
462 (e.g., a connection manager or a network administration tool such as
463 ss) to close sockets opened by other processes. Closing a socket in
464 this way interrupts any blocking read/write/connect operations on
465 the socket and causes future socket calls to behave as if the socket
466 had been disconnected.
467 If unsure, say N.
468
469menuconfig TCP_CONG_ADVANCED
470 bool "TCP: advanced congestion control"
471 help
472 Support for selection of various TCP congestion control
473 modules.
474
475 Nearly all users can safely say no here, and a safe default
476 selection will be made (CUBIC with new Reno as a fallback).
477
478 If unsure, say N.
479
480if TCP_CONG_ADVANCED
481
482config TCP_CONG_BIC
483 tristate "Binary Increase Congestion (BIC) control"
484 default m
485 help
486 BIC-TCP is a sender-side only change that ensures a linear RTT
487 fairness under large windows while offering both scalability and
488 bounded TCP-friendliness. The protocol combines two schemes
489 called additive increase and binary search increase. When the
490 congestion window is large, additive increase with a large
491 increment ensures linear RTT fairness as well as good
492 scalability. Under small congestion windows, binary search
493 increase provides TCP friendliness.
494 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
495
496config TCP_CONG_CUBIC
497 tristate "CUBIC TCP"
498 default y
499 help
500 This is version 2.0 of BIC-TCP which uses a cubic growth function
501 among other techniques.
502 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
503
504config TCP_CONG_WESTWOOD
505 tristate "TCP Westwood+"
506 default m
507 help
508 TCP Westwood+ is a sender-side only modification of the TCP Reno
509 protocol stack that optimizes the performance of TCP congestion
510 control. It is based on end-to-end bandwidth estimation to set
511 congestion window and slow start threshold after a congestion
512 episode. Using this estimation, TCP Westwood+ adaptively sets a
513 slow start threshold and a congestion window which takes into
514 account the bandwidth used at the time congestion is experienced.
515 TCP Westwood+ significantly increases fairness wrt TCP Reno in
516 wired networks and throughput over wireless links.
517
518config TCP_CONG_HTCP
519 tristate "H-TCP"
520 default m
521 help
522 H-TCP is a send-side only modifications of the TCP Reno
523 protocol stack that optimizes the performance of TCP
524 congestion control for high speed network links. It uses a
525 modeswitch to change the alpha and beta parameters of TCP Reno
526 based on network conditions and in a way so as to be fair with
527 other Reno and H-TCP flows.
528
529config TCP_CONG_HSTCP
530 tristate "High Speed TCP"
531 default n
532 help
533 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
534 A modification to TCP's congestion control mechanism for use
535 with large congestion windows. A table indicates how much to
536 increase the congestion window by when an ACK is received.
537 For more detail see https://www.icir.org/floyd/hstcp.html
538
539config TCP_CONG_HYBLA
540 tristate "TCP-Hybla congestion control algorithm"
541 default n
542 help
543 TCP-Hybla is a sender-side only change that eliminates penalization of
544 long-RTT, large-bandwidth connections, like when satellite legs are
545 involved, especially when sharing a common bottleneck with normal
546 terrestrial connections.
547
548config TCP_CONG_VEGAS
549 tristate "TCP Vegas"
550 default n
551 help
552 TCP Vegas is a sender-side only change to TCP that anticipates
553 the onset of congestion by estimating the bandwidth. TCP Vegas
554 adjusts the sending rate by modifying the congestion
555 window. TCP Vegas should provide less packet loss, but it is
556 not as aggressive as TCP Reno.
557
558config TCP_CONG_NV
559 tristate "TCP NV"
560 default n
561 help
562 TCP NV is a follow up to TCP Vegas. It has been modified to deal with
563 10G networks, measurement noise introduced by LRO, GRO and interrupt
564 coalescence. In addition, it will decrease its cwnd multiplicatively
565 instead of linearly.
566
567 Note that in general congestion avoidance (cwnd decreased when # packets
568 queued grows) cannot coexist with congestion control (cwnd decreased only
569 when there is packet loss) due to fairness issues. One scenario when they
570 can coexist safely is when the CA flows have RTTs << CC flows RTTs.
571
572 For further details see http://www.brakmo.org/networking/tcp-nv/
573
574config TCP_CONG_SCALABLE
575 tristate "Scalable TCP"
576 default n
577 help
578 Scalable TCP is a sender-side only change to TCP which uses a
579 MIMD congestion control algorithm which has some nice scaling
580 properties, though is known to have fairness issues.
581 See http://www.deneholme.net/tom/scalable/
582
583config TCP_CONG_LP
584 tristate "TCP Low Priority"
585 default n
586 help
587 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
588 to utilize only the excess network bandwidth as compared to the
589 ``fair share`` of bandwidth as targeted by TCP.
590 See http://www-ece.rice.edu/networks/TCP-LP/
591
592config TCP_CONG_VENO
593 tristate "TCP Veno"
594 default n
595 help
596 TCP Veno is a sender-side only enhancement of TCP to obtain better
597 throughput over wireless networks. TCP Veno makes use of state
598 distinguishing to circumvent the difficult judgment of the packet loss
599 type. TCP Veno cuts down less congestion window in response to random
600 loss packets.
601 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
602
603config TCP_CONG_YEAH
604 tristate "YeAH TCP"
605 select TCP_CONG_VEGAS
606 default n
607 help
608 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
609 algorithm, which uses a mixed loss/delay approach to compute the
610 congestion window. It's design goals target high efficiency,
611 internal, RTT and Reno fairness, resilience to link loss while
612 keeping network elements load as low as possible.
613
614 For further details look here:
615 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
616
617config TCP_CONG_ILLINOIS
618 tristate "TCP Illinois"
619 default n
620 help
621 TCP-Illinois is a sender-side modification of TCP Reno for
622 high speed long delay links. It uses round-trip-time to
623 adjust the alpha and beta parameters to achieve a higher average
624 throughput and maintain fairness.
625
626 For further details see:
627 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
628
629config TCP_CONG_DCTCP
630 tristate "DataCenter TCP (DCTCP)"
631 default n
632 help
633 DCTCP leverages Explicit Congestion Notification (ECN) in the network to
634 provide multi-bit feedback to the end hosts. It is designed to provide:
635
636 - High burst tolerance (incast due to partition/aggregate),
637 - Low latency (short flows, queries),
638 - High throughput (continuous data updates, large file transfers) with
639 commodity, shallow-buffered switches.
640
641 All switches in the data center network running DCTCP must support
642 ECN marking and be configured for marking when reaching defined switch
643 buffer thresholds. The default ECN marking threshold heuristic for
644 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
645 (~100KB) at 10Gbps, but might need further careful tweaking.
646
647 For further details see:
648 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
649
650config TCP_CONG_CDG
651 tristate "CAIA Delay-Gradient (CDG)"
652 default n
653 help
654 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
655 the TCP sender in order to:
656
657 o Use the delay gradient as a congestion signal.
658 o Back off with an average probability that is independent of the RTT.
659 o Coexist with flows that use loss-based congestion control.
660 o Tolerate packet loss unrelated to congestion.
661
662 For further details see:
663 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
664 delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg
665
666config TCP_CONG_BBR
667 tristate "BBR TCP"
668 default n
669 help
670
671 BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to
672 maximize network utilization and minimize queues. It builds an explicit
673 model of the bottleneck delivery rate and path round-trip propagation
674 delay. It tolerates packet loss and delay unrelated to congestion. It
675 can operate over LAN, WAN, cellular, wifi, or cable modem links. It can
676 coexist with flows that use loss-based congestion control, and can
677 operate with shallow buffers, deep buffers, bufferbloat, policers, or
678 AQM schemes that do not provide a delay signal. It requires the fq
679 ("Fair Queue") pacing packet scheduler.
680
681choice
682 prompt "Default TCP congestion control"
683 default DEFAULT_CUBIC
684 help
685 Select the TCP congestion control that will be used by default
686 for all connections.
687
688 config DEFAULT_BIC
689 bool "Bic" if TCP_CONG_BIC=y
690
691 config DEFAULT_CUBIC
692 bool "Cubic" if TCP_CONG_CUBIC=y
693
694 config DEFAULT_HTCP
695 bool "Htcp" if TCP_CONG_HTCP=y
696
697 config DEFAULT_HYBLA
698 bool "Hybla" if TCP_CONG_HYBLA=y
699
700 config DEFAULT_VEGAS
701 bool "Vegas" if TCP_CONG_VEGAS=y
702
703 config DEFAULT_VENO
704 bool "Veno" if TCP_CONG_VENO=y
705
706 config DEFAULT_WESTWOOD
707 bool "Westwood" if TCP_CONG_WESTWOOD=y
708
709 config DEFAULT_DCTCP
710 bool "DCTCP" if TCP_CONG_DCTCP=y
711
712 config DEFAULT_CDG
713 bool "CDG" if TCP_CONG_CDG=y
714
715 config DEFAULT_BBR
716 bool "BBR" if TCP_CONG_BBR=y
717
718 config DEFAULT_RENO
719 bool "Reno"
720endchoice
721
722endif
723
724config TCP_CONG_CUBIC
725 tristate
726 depends on !TCP_CONG_ADVANCED
727 default y
728
729config DEFAULT_TCP_CONG
730 string
731 default "bic" if DEFAULT_BIC
732 default "cubic" if DEFAULT_CUBIC
733 default "htcp" if DEFAULT_HTCP
734 default "hybla" if DEFAULT_HYBLA
735 default "vegas" if DEFAULT_VEGAS
736 default "westwood" if DEFAULT_WESTWOOD
737 default "veno" if DEFAULT_VENO
738 default "reno" if DEFAULT_RENO
739 default "dctcp" if DEFAULT_DCTCP
740 default "cdg" if DEFAULT_CDG
741 default "bbr" if DEFAULT_BBR
742 default "cubic"
743
744config TCP_SIGPOOL
745 tristate
746
747config TCP_AO
748 bool "TCP: Authentication Option (RFC5925)"
749 select CRYPTO
750 select TCP_SIGPOOL
751 depends on 64BIT && IPV6 != m # seq-number extension needs WRITE_ONCE(u64)
752 help
753 TCP-AO specifies the use of stronger Message Authentication Codes (MACs),
754 protects against replays for long-lived TCP connections, and
755 provides more details on the association of security with TCP
756 connections than TCP MD5 (See RFC5925)
757
758 If unsure, say N.
759
760config TCP_MD5SIG
761 bool "TCP: MD5 Signature Option support (RFC2385)"
762 select CRYPTO
763 select CRYPTO_MD5
764 select TCP_SIGPOOL
765 help
766 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
767 Its main (only?) use is to protect BGP sessions between core routers
768 on the Internet.
769
770 If unsure, say N.
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# IP configuration
4#
5config IP_MULTICAST
6 bool "IP: multicasting"
7 help
8 This is code for addressing several networked computers at once,
9 enlarging your kernel by about 2 KB. You need multicasting if you
10 intend to participate in the MBONE, a high bandwidth network on top
11 of the Internet which carries audio and video broadcasts. More
12 information about the MBONE is on the WWW at
13 <https://www.savetz.com/mbone/>. For most people, it's safe to say N.
14
15config IP_ADVANCED_ROUTER
16 bool "IP: advanced router"
17 help
18 If you intend to run your Linux box mostly as a router, i.e. as a
19 computer that forwards and redistributes network packets, say Y; you
20 will then be presented with several options that allow more precise
21 control about the routing process.
22
23 The answer to this question won't directly affect the kernel:
24 answering N will just cause the configurator to skip all the
25 questions about advanced routing.
26
27 Note that your box can only act as a router if you enable IP
28 forwarding in your kernel; you can do that by saying Y to "/proc
29 file system support" and "Sysctl support" below and executing the
30 line
31
32 echo "1" > /proc/sys/net/ipv4/ip_forward
33
34 at boot time after the /proc file system has been mounted.
35
36 If you turn on IP forwarding, you should consider the rp_filter, which
37 automatically rejects incoming packets if the routing table entry
38 for their source address doesn't match the network interface they're
39 arriving on. This has security advantages because it prevents the
40 so-called IP spoofing, however it can pose problems if you use
41 asymmetric routing (packets from you to a host take a different path
42 than packets from that host to you) or if you operate a non-routing
43 host which has several IP addresses on different interfaces. To turn
44 rp_filter on use:
45
46 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
47 or
48 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
49
50 Note that some distributions enable it in startup scripts.
51 For details about rp_filter strict and loose mode read
52 <file:Documentation/networking/ip-sysctl.rst>.
53
54 If unsure, say N here.
55
56config IP_FIB_TRIE_STATS
57 bool "FIB TRIE statistics"
58 depends on IP_ADVANCED_ROUTER
59 help
60 Keep track of statistics on structure of FIB TRIE table.
61 Useful for testing and measuring TRIE performance.
62
63config IP_MULTIPLE_TABLES
64 bool "IP: policy routing"
65 depends on IP_ADVANCED_ROUTER
66 select FIB_RULES
67 help
68 Normally, a router decides what to do with a received packet based
69 solely on the packet's final destination address. If you say Y here,
70 the Linux router will also be able to take the packet's source
71 address into account. Furthermore, the TOS (Type-Of-Service) field
72 of the packet can be used for routing decisions as well.
73
74 If you need more information, see the Linux Advanced
75 Routing and Traffic Control documentation at
76 <https://lartc.org/howto/lartc.rpdb.html>
77
78 If unsure, say N.
79
80config IP_ROUTE_MULTIPATH
81 bool "IP: equal cost multipath"
82 depends on IP_ADVANCED_ROUTER
83 help
84 Normally, the routing tables specify a single action to be taken in
85 a deterministic manner for a given packet. If you say Y here
86 however, it becomes possible to attach several actions to a packet
87 pattern, in effect specifying several alternative paths to travel
88 for those packets. The router considers all these paths to be of
89 equal "cost" and chooses one of them in a non-deterministic fashion
90 if a matching packet arrives.
91
92config IP_ROUTE_VERBOSE
93 bool "IP: verbose route monitoring"
94 depends on IP_ADVANCED_ROUTER
95 help
96 If you say Y here, which is recommended, then the kernel will print
97 verbose messages regarding the routing, for example warnings about
98 received packets which look strange and could be evidence of an
99 attack or a misconfigured system somewhere. The information is
100 handled by the klogd daemon which is responsible for kernel messages
101 ("man klogd").
102
103config IP_ROUTE_CLASSID
104 bool
105
106config IP_PNP
107 bool "IP: kernel level autoconfiguration"
108 help
109 This enables automatic configuration of IP addresses of devices and
110 of the routing table during kernel boot, based on either information
111 supplied on the kernel command line or by BOOTP or RARP protocols.
112 You need to say Y only for diskless machines requiring network
113 access to boot (in which case you want to say Y to "Root file system
114 on NFS" as well), because all other machines configure the network
115 in their startup scripts.
116
117config IP_PNP_DHCP
118 bool "IP: DHCP support"
119 depends on IP_PNP
120 help
121 If you want your Linux box to mount its whole root file system (the
122 one containing the directory /) from some other computer over the
123 net via NFS and you want the IP address of your computer to be
124 discovered automatically at boot time using the DHCP protocol (a
125 special protocol designed for doing this job), say Y here. In case
126 the boot ROM of your network card was designed for booting Linux and
127 does DHCP itself, providing all necessary information on the kernel
128 command line, you can say N here.
129
130 If unsure, say Y. Note that if you want to use DHCP, a DHCP server
131 must be operating on your network. Read
132 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
133
134config IP_PNP_BOOTP
135 bool "IP: BOOTP support"
136 depends on IP_PNP
137 help
138 If you want your Linux box to mount its whole root file system (the
139 one containing the directory /) from some other computer over the
140 net via NFS and you want the IP address of your computer to be
141 discovered automatically at boot time using the BOOTP protocol (a
142 special protocol designed for doing this job), say Y here. In case
143 the boot ROM of your network card was designed for booting Linux and
144 does BOOTP itself, providing all necessary information on the kernel
145 command line, you can say N here. If unsure, say Y. Note that if you
146 want to use BOOTP, a BOOTP server must be operating on your network.
147 Read <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
148
149config IP_PNP_RARP
150 bool "IP: RARP support"
151 depends on IP_PNP
152 help
153 If you want your Linux box to mount its whole root file system (the
154 one containing the directory /) from some other computer over the
155 net via NFS and you want the IP address of your computer to be
156 discovered automatically at boot time using the RARP protocol (an
157 older protocol which is being obsoleted by BOOTP and DHCP), say Y
158 here. Note that if you want to use RARP, a RARP server must be
159 operating on your network. Read
160 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details.
161
162config NET_IPIP
163 tristate "IP: tunneling"
164 select INET_TUNNEL
165 select NET_IP_TUNNEL
166 help
167 Tunneling means encapsulating data of one protocol type within
168 another protocol and sending it over a channel that understands the
169 encapsulating protocol. This particular tunneling driver implements
170 encapsulation of IP within IP, which sounds kind of pointless, but
171 can be useful if you want to make your (or some other) machine
172 appear on a different network than it physically is, or to use
173 mobile-IP facilities (allowing laptops to seamlessly move between
174 networks without changing their IP addresses).
175
176 Saying Y to this option will produce two modules ( = code which can
177 be inserted in and removed from the running kernel whenever you
178 want). Most people won't need this and can say N.
179
180config NET_IPGRE_DEMUX
181 tristate "IP: GRE demultiplexer"
182 help
183 This is helper module to demultiplex GRE packets on GRE version field criteria.
184 Required by ip_gre and pptp modules.
185
186config NET_IP_TUNNEL
187 tristate
188 select DST_CACHE
189 select GRO_CELLS
190 default n
191
192config NET_IPGRE
193 tristate "IP: GRE tunnels over IP"
194 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
195 select NET_IP_TUNNEL
196 help
197 Tunneling means encapsulating data of one protocol type within
198 another protocol and sending it over a channel that understands the
199 encapsulating protocol. This particular tunneling driver implements
200 GRE (Generic Routing Encapsulation) and at this time allows
201 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
202 This driver is useful if the other endpoint is a Cisco router: Cisco
203 likes GRE much better than the other Linux tunneling driver ("IP
204 tunneling" above). In addition, GRE allows multicast redistribution
205 through the tunnel.
206
207config NET_IPGRE_BROADCAST
208 bool "IP: broadcast GRE over IP"
209 depends on IP_MULTICAST && NET_IPGRE
210 help
211 One application of GRE/IP is to construct a broadcast WAN (Wide Area
212 Network), which looks like a normal Ethernet LAN (Local Area
213 Network), but can be distributed all over the Internet. If you want
214 to do that, say Y here and to "IP multicast routing" below.
215
216config IP_MROUTE_COMMON
217 bool
218 depends on IP_MROUTE || IPV6_MROUTE
219
220config IP_MROUTE
221 bool "IP: multicast routing"
222 depends on IP_MULTICAST
223 select IP_MROUTE_COMMON
224 help
225 This is used if you want your machine to act as a router for IP
226 packets that have several destination addresses. It is needed on the
227 MBONE, a high bandwidth network on top of the Internet which carries
228 audio and video broadcasts. In order to do that, you would most
229 likely run the program mrouted. If you haven't heard about it, you
230 don't need it.
231
232config IP_MROUTE_MULTIPLE_TABLES
233 bool "IP: multicast policy routing"
234 depends on IP_MROUTE && IP_ADVANCED_ROUTER
235 select FIB_RULES
236 help
237 Normally, a multicast router runs a userspace daemon and decides
238 what to do with a multicast packet based on the source and
239 destination addresses. If you say Y here, the multicast router
240 will also be able to take interfaces and packet marks into
241 account and run multiple instances of userspace daemons
242 simultaneously, each one handling a single table.
243
244 If unsure, say N.
245
246config IP_PIMSM_V1
247 bool "IP: PIM-SM version 1 support"
248 depends on IP_MROUTE
249 help
250 Kernel side support for Sparse Mode PIM (Protocol Independent
251 Multicast) version 1. This multicast routing protocol is used widely
252 because Cisco supports it. You need special software to use it
253 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
254 information about PIM.
255
256 Say Y if you want to use PIM-SM v1. Note that you can say N here if
257 you just want to use Dense Mode PIM.
258
259config IP_PIMSM_V2
260 bool "IP: PIM-SM version 2 support"
261 depends on IP_MROUTE
262 help
263 Kernel side support for Sparse Mode PIM version 2. In order to use
264 this, you need an experimental routing daemon supporting it (pimd or
265 gated-5). This routing protocol is not used widely, so say N unless
266 you want to play with it.
267
268config SYN_COOKIES
269 bool "IP: TCP syncookie support"
270 help
271 Normal TCP/IP networking is open to an attack known as "SYN
272 flooding". This denial-of-service attack prevents legitimate remote
273 users from being able to connect to your computer during an ongoing
274 attack and requires very little work from the attacker, who can
275 operate from anywhere on the Internet.
276
277 SYN cookies provide protection against this type of attack. If you
278 say Y here, the TCP/IP stack will use a cryptographic challenge
279 protocol known as "SYN cookies" to enable legitimate users to
280 continue to connect, even when your machine is under attack. There
281 is no need for the legitimate users to change their TCP/IP software;
282 SYN cookies work transparently to them. For technical information
283 about SYN cookies, check out <https://cr.yp.to/syncookies.html>.
284
285 If you are SYN flooded, the source address reported by the kernel is
286 likely to have been forged by the attacker; it is only reported as
287 an aid in tracing the packets to their actual source and should not
288 be taken as absolute truth.
289
290 SYN cookies may prevent correct error reporting on clients when the
291 server is really overloaded. If this happens frequently better turn
292 them off.
293
294 If you say Y here, you can disable SYN cookies at run time by
295 saying Y to "/proc file system support" and
296 "Sysctl support" below and executing the command
297
298 echo 0 > /proc/sys/net/ipv4/tcp_syncookies
299
300 after the /proc file system has been mounted.
301
302 If unsure, say N.
303
304config NET_IPVTI
305 tristate "Virtual (secure) IP: tunneling"
306 depends on IPV6 || IPV6=n
307 select INET_TUNNEL
308 select NET_IP_TUNNEL
309 select XFRM
310 help
311 Tunneling means encapsulating data of one protocol type within
312 another protocol and sending it over a channel that understands the
313 encapsulating protocol. This can be used with xfrm mode tunnel to give
314 the notion of a secure tunnel for IPSEC and then use routing protocol
315 on top.
316
317config NET_UDP_TUNNEL
318 tristate
319 select NET_IP_TUNNEL
320 default n
321
322config NET_FOU
323 tristate "IP: Foo (IP protocols) over UDP"
324 select NET_UDP_TUNNEL
325 help
326 Foo over UDP allows any IP protocol to be directly encapsulated
327 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
328 network mechanisms and optimizations for UDP (such as ECMP
329 and RSS) can be leveraged to provide better service.
330
331config NET_FOU_IP_TUNNELS
332 bool "IP: FOU encapsulation of IP tunnels"
333 depends on NET_IPIP || NET_IPGRE || IPV6_SIT
334 select NET_FOU
335 help
336 Allow configuration of FOU or GUE encapsulation for IP tunnels.
337 When this option is enabled IP tunnels can be configured to use
338 FOU or GUE encapsulation.
339
340config INET_AH
341 tristate "IP: AH transformation"
342 select XFRM_AH
343 help
344 Support for IPsec AH (Authentication Header).
345
346 AH can be used with various authentication algorithms. Besides
347 enabling AH support itself, this option enables the generic
348 implementations of the algorithms that RFC 8221 lists as MUST be
349 implemented. If you need any other algorithms, you'll need to enable
350 them in the crypto API. You should also enable accelerated
351 implementations of any needed algorithms when available.
352
353 If unsure, say Y.
354
355config INET_ESP
356 tristate "IP: ESP transformation"
357 select XFRM_ESP
358 help
359 Support for IPsec ESP (Encapsulating Security Payload).
360
361 ESP can be used with various encryption and authentication algorithms.
362 Besides enabling ESP support itself, this option enables the generic
363 implementations of the algorithms that RFC 8221 lists as MUST be
364 implemented. If you need any other algorithms, you'll need to enable
365 them in the crypto API. You should also enable accelerated
366 implementations of any needed algorithms when available.
367
368 If unsure, say Y.
369
370config INET_ESP_OFFLOAD
371 tristate "IP: ESP transformation offload"
372 depends on INET_ESP
373 select XFRM_OFFLOAD
374 default n
375 help
376 Support for ESP transformation offload. This makes sense
377 only if this system really does IPsec and want to do it
378 with high throughput. A typical desktop system does not
379 need it, even if it does IPsec.
380
381 If unsure, say N.
382
383config INET_ESPINTCP
384 bool "IP: ESP in TCP encapsulation (RFC 8229)"
385 depends on XFRM && INET_ESP
386 select STREAM_PARSER
387 select NET_SOCK_MSG
388 select XFRM_ESPINTCP
389 help
390 Support for RFC 8229 encapsulation of ESP and IKE over
391 TCP/IPv4 sockets.
392
393 If unsure, say N.
394
395config INET_IPCOMP
396 tristate "IP: IPComp transformation"
397 select INET_XFRM_TUNNEL
398 select XFRM_IPCOMP
399 help
400 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
401 typically needed for IPsec.
402
403 If unsure, say Y.
404
405config INET_TABLE_PERTURB_ORDER
406 int "INET: Source port perturbation table size (as power of 2)" if EXPERT
407 default 16
408 help
409 Source port perturbation table size (as power of 2) for
410 RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm.
411
412 The default is almost always what you want.
413 Only change this if you know what you are doing.
414
415config INET_XFRM_TUNNEL
416 tristate
417 select INET_TUNNEL
418 default n
419
420config INET_TUNNEL
421 tristate
422 default n
423
424config INET_DIAG
425 tristate "INET: socket monitoring interface"
426 default y
427 help
428 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
429 native Linux tools such as ss. ss is included in iproute2, currently
430 downloadable at:
431
432 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
433
434 If unsure, say Y.
435
436config INET_TCP_DIAG
437 depends on INET_DIAG
438 def_tristate INET_DIAG
439
440config INET_UDP_DIAG
441 tristate "UDP: socket monitoring interface"
442 depends on INET_DIAG && (IPV6 || IPV6=n)
443 default n
444 help
445 Support for UDP socket monitoring interface used by the ss tool.
446 If unsure, say Y.
447
448config INET_RAW_DIAG
449 tristate "RAW: socket monitoring interface"
450 depends on INET_DIAG && (IPV6 || IPV6=n)
451 default n
452 help
453 Support for RAW socket monitoring interface used by the ss tool.
454 If unsure, say Y.
455
456config INET_DIAG_DESTROY
457 bool "INET: allow privileged process to administratively close sockets"
458 depends on INET_DIAG
459 default n
460 help
461 Provides a SOCK_DESTROY operation that allows privileged processes
462 (e.g., a connection manager or a network administration tool such as
463 ss) to close sockets opened by other processes. Closing a socket in
464 this way interrupts any blocking read/write/connect operations on
465 the socket and causes future socket calls to behave as if the socket
466 had been disconnected.
467 If unsure, say N.
468
469menuconfig TCP_CONG_ADVANCED
470 bool "TCP: advanced congestion control"
471 help
472 Support for selection of various TCP congestion control
473 modules.
474
475 Nearly all users can safely say no here, and a safe default
476 selection will be made (CUBIC with new Reno as a fallback).
477
478 If unsure, say N.
479
480if TCP_CONG_ADVANCED
481
482config TCP_CONG_BIC
483 tristate "Binary Increase Congestion (BIC) control"
484 default m
485 help
486 BIC-TCP is a sender-side only change that ensures a linear RTT
487 fairness under large windows while offering both scalability and
488 bounded TCP-friendliness. The protocol combines two schemes
489 called additive increase and binary search increase. When the
490 congestion window is large, additive increase with a large
491 increment ensures linear RTT fairness as well as good
492 scalability. Under small congestion windows, binary search
493 increase provides TCP friendliness.
494 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
495
496config TCP_CONG_CUBIC
497 tristate "CUBIC TCP"
498 default y
499 help
500 This is version 2.0 of BIC-TCP which uses a cubic growth function
501 among other techniques.
502 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
503
504config TCP_CONG_WESTWOOD
505 tristate "TCP Westwood+"
506 default m
507 help
508 TCP Westwood+ is a sender-side only modification of the TCP Reno
509 protocol stack that optimizes the performance of TCP congestion
510 control. It is based on end-to-end bandwidth estimation to set
511 congestion window and slow start threshold after a congestion
512 episode. Using this estimation, TCP Westwood+ adaptively sets a
513 slow start threshold and a congestion window which takes into
514 account the bandwidth used at the time congestion is experienced.
515 TCP Westwood+ significantly increases fairness wrt TCP Reno in
516 wired networks and throughput over wireless links.
517
518config TCP_CONG_HTCP
519 tristate "H-TCP"
520 default m
521 help
522 H-TCP is a send-side only modifications of the TCP Reno
523 protocol stack that optimizes the performance of TCP
524 congestion control for high speed network links. It uses a
525 modeswitch to change the alpha and beta parameters of TCP Reno
526 based on network conditions and in a way so as to be fair with
527 other Reno and H-TCP flows.
528
529config TCP_CONG_HSTCP
530 tristate "High Speed TCP"
531 default n
532 help
533 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
534 A modification to TCP's congestion control mechanism for use
535 with large congestion windows. A table indicates how much to
536 increase the congestion window by when an ACK is received.
537 For more detail see https://www.icir.org/floyd/hstcp.html
538
539config TCP_CONG_HYBLA
540 tristate "TCP-Hybla congestion control algorithm"
541 default n
542 help
543 TCP-Hybla is a sender-side only change that eliminates penalization of
544 long-RTT, large-bandwidth connections, like when satellite legs are
545 involved, especially when sharing a common bottleneck with normal
546 terrestrial connections.
547
548config TCP_CONG_VEGAS
549 tristate "TCP Vegas"
550 default n
551 help
552 TCP Vegas is a sender-side only change to TCP that anticipates
553 the onset of congestion by estimating the bandwidth. TCP Vegas
554 adjusts the sending rate by modifying the congestion
555 window. TCP Vegas should provide less packet loss, but it is
556 not as aggressive as TCP Reno.
557
558config TCP_CONG_NV
559 tristate "TCP NV"
560 default n
561 help
562 TCP NV is a follow up to TCP Vegas. It has been modified to deal with
563 10G networks, measurement noise introduced by LRO, GRO and interrupt
564 coalescence. In addition, it will decrease its cwnd multiplicatively
565 instead of linearly.
566
567 Note that in general congestion avoidance (cwnd decreased when # packets
568 queued grows) cannot coexist with congestion control (cwnd decreased only
569 when there is packet loss) due to fairness issues. One scenario when they
570 can coexist safely is when the CA flows have RTTs << CC flows RTTs.
571
572 For further details see http://www.brakmo.org/networking/tcp-nv/
573
574config TCP_CONG_SCALABLE
575 tristate "Scalable TCP"
576 default n
577 help
578 Scalable TCP is a sender-side only change to TCP which uses a
579 MIMD congestion control algorithm which has some nice scaling
580 properties, though is known to have fairness issues.
581 See http://www.deneholme.net/tom/scalable/
582
583config TCP_CONG_LP
584 tristate "TCP Low Priority"
585 default n
586 help
587 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
588 to utilize only the excess network bandwidth as compared to the
589 ``fair share`` of bandwidth as targeted by TCP.
590 See http://www-ece.rice.edu/networks/TCP-LP/
591
592config TCP_CONG_VENO
593 tristate "TCP Veno"
594 default n
595 help
596 TCP Veno is a sender-side only enhancement of TCP to obtain better
597 throughput over wireless networks. TCP Veno makes use of state
598 distinguishing to circumvent the difficult judgment of the packet loss
599 type. TCP Veno cuts down less congestion window in response to random
600 loss packets.
601 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
602
603config TCP_CONG_YEAH
604 tristate "YeAH TCP"
605 select TCP_CONG_VEGAS
606 default n
607 help
608 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
609 algorithm, which uses a mixed loss/delay approach to compute the
610 congestion window. It's design goals target high efficiency,
611 internal, RTT and Reno fairness, resilience to link loss while
612 keeping network elements load as low as possible.
613
614 For further details look here:
615 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
616
617config TCP_CONG_ILLINOIS
618 tristate "TCP Illinois"
619 default n
620 help
621 TCP-Illinois is a sender-side modification of TCP Reno for
622 high speed long delay links. It uses round-trip-time to
623 adjust the alpha and beta parameters to achieve a higher average
624 throughput and maintain fairness.
625
626 For further details see:
627 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
628
629config TCP_CONG_DCTCP
630 tristate "DataCenter TCP (DCTCP)"
631 default n
632 help
633 DCTCP leverages Explicit Congestion Notification (ECN) in the network to
634 provide multi-bit feedback to the end hosts. It is designed to provide:
635
636 - High burst tolerance (incast due to partition/aggregate),
637 - Low latency (short flows, queries),
638 - High throughput (continuous data updates, large file transfers) with
639 commodity, shallow-buffered switches.
640
641 All switches in the data center network running DCTCP must support
642 ECN marking and be configured for marking when reaching defined switch
643 buffer thresholds. The default ECN marking threshold heuristic for
644 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
645 (~100KB) at 10Gbps, but might need further careful tweaking.
646
647 For further details see:
648 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
649
650config TCP_CONG_CDG
651 tristate "CAIA Delay-Gradient (CDG)"
652 default n
653 help
654 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
655 the TCP sender in order to:
656
657 o Use the delay gradient as a congestion signal.
658 o Back off with an average probability that is independent of the RTT.
659 o Coexist with flows that use loss-based congestion control.
660 o Tolerate packet loss unrelated to congestion.
661
662 For further details see:
663 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
664 delay gradients." In Networking 2011. Preprint:
665 http://caia.swin.edu.au/cv/dahayes/content/networking2011-cdg-preprint.pdf
666
667config TCP_CONG_BBR
668 tristate "BBR TCP"
669 default n
670 help
671
672 BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to
673 maximize network utilization and minimize queues. It builds an explicit
674 model of the bottleneck delivery rate and path round-trip propagation
675 delay. It tolerates packet loss and delay unrelated to congestion. It
676 can operate over LAN, WAN, cellular, wifi, or cable modem links. It can
677 coexist with flows that use loss-based congestion control, and can
678 operate with shallow buffers, deep buffers, bufferbloat, policers, or
679 AQM schemes that do not provide a delay signal. It requires the fq
680 ("Fair Queue") pacing packet scheduler.
681
682choice
683 prompt "Default TCP congestion control"
684 default DEFAULT_CUBIC
685 help
686 Select the TCP congestion control that will be used by default
687 for all connections.
688
689 config DEFAULT_BIC
690 bool "Bic" if TCP_CONG_BIC=y
691
692 config DEFAULT_CUBIC
693 bool "Cubic" if TCP_CONG_CUBIC=y
694
695 config DEFAULT_HTCP
696 bool "Htcp" if TCP_CONG_HTCP=y
697
698 config DEFAULT_HYBLA
699 bool "Hybla" if TCP_CONG_HYBLA=y
700
701 config DEFAULT_VEGAS
702 bool "Vegas" if TCP_CONG_VEGAS=y
703
704 config DEFAULT_VENO
705 bool "Veno" if TCP_CONG_VENO=y
706
707 config DEFAULT_WESTWOOD
708 bool "Westwood" if TCP_CONG_WESTWOOD=y
709
710 config DEFAULT_DCTCP
711 bool "DCTCP" if TCP_CONG_DCTCP=y
712
713 config DEFAULT_CDG
714 bool "CDG" if TCP_CONG_CDG=y
715
716 config DEFAULT_BBR
717 bool "BBR" if TCP_CONG_BBR=y
718
719 config DEFAULT_RENO
720 bool "Reno"
721endchoice
722
723endif
724
725config TCP_CONG_CUBIC
726 tristate
727 depends on !TCP_CONG_ADVANCED
728 default y
729
730config DEFAULT_TCP_CONG
731 string
732 default "bic" if DEFAULT_BIC
733 default "cubic" if DEFAULT_CUBIC
734 default "htcp" if DEFAULT_HTCP
735 default "hybla" if DEFAULT_HYBLA
736 default "vegas" if DEFAULT_VEGAS
737 default "westwood" if DEFAULT_WESTWOOD
738 default "veno" if DEFAULT_VENO
739 default "reno" if DEFAULT_RENO
740 default "dctcp" if DEFAULT_DCTCP
741 default "cdg" if DEFAULT_CDG
742 default "bbr" if DEFAULT_BBR
743 default "cubic"
744
745config TCP_SIGPOOL
746 tristate
747
748config TCP_AO
749 bool "TCP: Authentication Option (RFC5925)"
750 select CRYPTO
751 select TCP_SIGPOOL
752 depends on 64BIT && IPV6 != m # seq-number extension needs WRITE_ONCE(u64)
753 help
754 TCP-AO specifies the use of stronger Message Authentication Codes (MACs),
755 protects against replays for long-lived TCP connections, and
756 provides more details on the association of security with TCP
757 connections than TCP MD5 (See RFC5925)
758
759 If unsure, say N.
760
761config TCP_MD5SIG
762 bool "TCP: MD5 Signature Option support (RFC2385)"
763 select CRYPTO
764 select CRYPTO_MD5
765 select TCP_SIGPOOL
766 help
767 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
768 Its main (only?) use is to protect BGP sessions between core routers
769 on the Internet.
770
771 If unsure, say N.