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  1 #
  2 # IP configuration
  3 #
  4 config IP_MULTICAST
  5         bool "IP: multicasting"
  6         help
  7           This is code for addressing several networked computers at once,
  8           enlarging your kernel by about 2 KB. You need multicasting if you
  9           intend to participate in the MBONE, a high bandwidth network on top
 10           of the Internet which carries audio and video broadcasts. More
 11           information about the MBONE is on the WWW at
 12           <>. For most people, it's safe to say N.
 15         bool "IP: advanced router"
 16         ---help---
 17           If you intend to run your Linux box mostly as a router, i.e. as a
 18           computer that forwards and redistributes network packets, say Y; you
 19           will then be presented with several options that allow more precise
 20           control about the routing process.
 22           The answer to this question won't directly affect the kernel:
 23           answering N will just cause the configurator to skip all the
 24           questions about advanced routing.
 26           Note that your box can only act as a router if you enable IP
 27           forwarding in your kernel; you can do that by saying Y to "/proc
 28           file system support" and "Sysctl support" below and executing the
 29           line
 31           echo "1" > /proc/sys/net/ipv4/ip_forward
 33           at boot time after the /proc file system has been mounted.
 35           If you turn on IP forwarding, you should consider the rp_filter, which
 36           automatically rejects incoming packets if the routing table entry
 37           for their source address doesn't match the network interface they're
 38           arriving on. This has security advantages because it prevents the
 39           so-called IP spoofing, however it can pose problems if you use
 40           asymmetric routing (packets from you to a host take a different path
 41           than packets from that host to you) or if you operate a non-routing
 42           host which has several IP addresses on different interfaces. To turn
 43           rp_filter on use:
 45           echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
 46            or
 47           echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
 49           Note that some distributions enable it in startup scripts.
 50           For details about rp_filter strict and loose mode read
 51           <file:Documentation/networking/ip-sysctl.txt>.
 53           If unsure, say N here.
 55 config IP_FIB_TRIE_STATS
 56         bool "FIB TRIE statistics"
 57         depends on IP_ADVANCED_ROUTER
 58         ---help---
 59           Keep track of statistics on structure of FIB TRIE table.
 60           Useful for testing and measuring TRIE performance.
 63         bool "IP: policy routing"
 64         depends on IP_ADVANCED_ROUTER
 65         select FIB_RULES
 66         ---help---
 67           Normally, a router decides what to do with a received packet based
 68           solely on the packet's final destination address. If you say Y here,
 69           the Linux router will also be able to take the packet's source
 70           address into account. Furthermore, the TOS (Type-Of-Service) field
 71           of the packet can be used for routing decisions as well.
 73           If you are interested in this, please see the preliminary
 74           documentation at <>
 75           and <>.
 76           You will need supporting software from
 77           <>.
 79           If unsure, say N.
 82         bool "IP: equal cost multipath"
 83         depends on IP_ADVANCED_ROUTER
 84         help
 85           Normally, the routing tables specify a single action to be taken in
 86           a deterministic manner for a given packet. If you say Y here
 87           however, it becomes possible to attach several actions to a packet
 88           pattern, in effect specifying several alternative paths to travel
 89           for those packets. The router considers all these paths to be of
 90           equal "cost" and chooses one of them in a non-deterministic fashion
 91           if a matching packet arrives.
 94         bool "IP: verbose route monitoring"
 95         depends on IP_ADVANCED_ROUTER
 96         help
 97           If you say Y here, which is recommended, then the kernel will print
 98           verbose messages regarding the routing, for example warnings about
 99           received packets which look strange and could be evidence of an
100           attack or a misconfigured system somewhere. The information is
101           handled by the klogd daemon which is responsible for kernel messages
102           ("man klogd").
105         bool
107 config IP_PNP
108         bool "IP: kernel level autoconfiguration"
109         help
110           This enables automatic configuration of IP addresses of devices and
111           of the routing table during kernel boot, based on either information
112           supplied on the kernel command line or by BOOTP or RARP protocols.
113           You need to say Y only for diskless machines requiring network
114           access to boot (in which case you want to say Y to "Root file system
115           on NFS" as well), because all other machines configure the network
116           in their startup scripts.
118 config IP_PNP_DHCP
119         bool "IP: DHCP support"
120         depends on IP_PNP
121         ---help---
122           If you want your Linux box to mount its whole root file system (the
123           one containing the directory /) from some other computer over the
124           net via NFS and you want the IP address of your computer to be
125           discovered automatically at boot time using the DHCP protocol (a
126           special protocol designed for doing this job), say Y here. In case
127           the boot ROM of your network card was designed for booting Linux and
128           does DHCP itself, providing all necessary information on the kernel
129           command line, you can say N here.
131           If unsure, say Y. Note that if you want to use DHCP, a DHCP server
132           must be operating on your network.  Read
133           <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
135 config IP_PNP_BOOTP
136         bool "IP: BOOTP support"
137         depends on IP_PNP
138         ---help---
139           If you want your Linux box to mount its whole root file system (the
140           one containing the directory /) from some other computer over the
141           net via NFS and you want the IP address of your computer to be
142           discovered automatically at boot time using the BOOTP protocol (a
143           special protocol designed for doing this job), say Y here. In case
144           the boot ROM of your network card was designed for booting Linux and
145           does BOOTP itself, providing all necessary information on the kernel
146           command line, you can say N here. If unsure, say Y. Note that if you
147           want to use BOOTP, a BOOTP server must be operating on your network.
148           Read <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
150 config IP_PNP_RARP
151         bool "IP: RARP support"
152         depends on IP_PNP
153         help
154           If you want your Linux box to mount its whole root file system (the
155           one containing the directory /) from some other computer over the
156           net via NFS and you want the IP address of your computer to be
157           discovered automatically at boot time using the RARP protocol (an
158           older protocol which is being obsoleted by BOOTP and DHCP), say Y
159           here. Note that if you want to use RARP, a RARP server must be
160           operating on your network. Read
161           <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
163 config NET_IPIP
164         tristate "IP: tunneling"
165         select INET_TUNNEL
166         select NET_IP_TUNNEL
167         ---help---
168           Tunneling means encapsulating data of one protocol type within
169           another protocol and sending it over a channel that understands the
170           encapsulating protocol. This particular tunneling driver implements
171           encapsulation of IP within IP, which sounds kind of pointless, but
172           can be useful if you want to make your (or some other) machine
173           appear on a different network than it physically is, or to use
174           mobile-IP facilities (allowing laptops to seamlessly move between
175           networks without changing their IP addresses).
177           Saying Y to this option will produce two modules ( = code which can
178           be inserted in and removed from the running kernel whenever you
179           want). Most people won't need this and can say N.
181 config NET_IPGRE_DEMUX
182         tristate "IP: GRE demultiplexer"
183         help
184          This is helper module to demultiplex GRE packets on GRE version field criteria.
185          Required by ip_gre and pptp modules.
187 config NET_IP_TUNNEL
188         tristate
189         default n
191 config NET_IPGRE
192         tristate "IP: GRE tunnels over IP"
193         depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
194         select NET_IP_TUNNEL
195         help
196           Tunneling means encapsulating data of one protocol type within
197           another protocol and sending it over a channel that understands the
198           encapsulating protocol. This particular tunneling driver implements
199           GRE (Generic Routing Encapsulation) and at this time allows
200           encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
201           This driver is useful if the other endpoint is a Cisco router: Cisco
202           likes GRE much better than the other Linux tunneling driver ("IP
203           tunneling" above). In addition, GRE allows multicast redistribution
204           through the tunnel.
207         bool "IP: broadcast GRE over IP"
208         depends on IP_MULTICAST && NET_IPGRE
209         help
210           One application of GRE/IP is to construct a broadcast WAN (Wide Area
211           Network), which looks like a normal Ethernet LAN (Local Area
212           Network), but can be distributed all over the Internet. If you want
213           to do that, say Y here and to "IP multicast routing" below.
215 config IP_MROUTE
216         bool "IP: multicast routing"
217         depends on IP_MULTICAST
218         help
219           This is used if you want your machine to act as a router for IP
220           packets that have several destination addresses. It is needed on the
221           MBONE, a high bandwidth network on top of the Internet which carries
222           audio and video broadcasts. In order to do that, you would most
223           likely run the program mrouted. If you haven't heard about it, you
224           don't need it.
227         bool "IP: multicast policy routing"
228         depends on IP_MROUTE && IP_ADVANCED_ROUTER
229         select FIB_RULES
230         help
231           Normally, a multicast router runs a userspace daemon and decides
232           what to do with a multicast packet based on the source and
233           destination addresses. If you say Y here, the multicast router
234           will also be able to take interfaces and packet marks into
235           account and run multiple instances of userspace daemons
236           simultaneously, each one handling a single table.
238           If unsure, say N.
240 config IP_PIMSM_V1
241         bool "IP: PIM-SM version 1 support"
242         depends on IP_MROUTE
243         help
244           Kernel side support for Sparse Mode PIM (Protocol Independent
245           Multicast) version 1. This multicast routing protocol is used widely
246           because Cisco supports it. You need special software to use it
247           (pimd-v1). Please see <> for more
248           information about PIM.
250           Say Y if you want to use PIM-SM v1. Note that you can say N here if
251           you just want to use Dense Mode PIM.
253 config IP_PIMSM_V2
254         bool "IP: PIM-SM version 2 support"
255         depends on IP_MROUTE
256         help
257           Kernel side support for Sparse Mode PIM version 2. In order to use
258           this, you need an experimental routing daemon supporting it (pimd or
259           gated-5). This routing protocol is not used widely, so say N unless
260           you want to play with it.
262 config SYN_COOKIES
263         bool "IP: TCP syncookie support"
264         ---help---
265           Normal TCP/IP networking is open to an attack known as "SYN
266           flooding". This denial-of-service attack prevents legitimate remote
267           users from being able to connect to your computer during an ongoing
268           attack and requires very little work from the attacker, who can
269           operate from anywhere on the Internet.
271           SYN cookies provide protection against this type of attack. If you
272           say Y here, the TCP/IP stack will use a cryptographic challenge
273           protocol known as "SYN cookies" to enable legitimate users to
274           continue to connect, even when your machine is under attack. There
275           is no need for the legitimate users to change their TCP/IP software;
276           SYN cookies work transparently to them. For technical information
277           about SYN cookies, check out <>.
279           If you are SYN flooded, the source address reported by the kernel is
280           likely to have been forged by the attacker; it is only reported as
281           an aid in tracing the packets to their actual source and should not
282           be taken as absolute truth.
284           SYN cookies may prevent correct error reporting on clients when the
285           server is really overloaded. If this happens frequently better turn
286           them off.
288           If you say Y here, you can disable SYN cookies at run time by
289           saying Y to "/proc file system support" and
290           "Sysctl support" below and executing the command
292           echo 0 > /proc/sys/net/ipv4/tcp_syncookies
294           after the /proc file system has been mounted.
296           If unsure, say N.
298 config NET_IPVTI
299         tristate "Virtual (secure) IP: tunneling"
300         select INET_TUNNEL
301         select NET_IP_TUNNEL
302         depends on INET_XFRM_MODE_TUNNEL
303         ---help---
304           Tunneling means encapsulating data of one protocol type within
305           another protocol and sending it over a channel that understands the
306           encapsulating protocol. This can be used with xfrm mode tunnel to give
307           the notion of a secure tunnel for IPSEC and then use routing protocol
308           on top.
310 config NET_UDP_TUNNEL
311         tristate
312         select NET_IP_TUNNEL
313         default n
315 config NET_FOU
316         tristate "IP: Foo (IP protocols) over UDP"
317         select XFRM
318         select NET_UDP_TUNNEL
319         ---help---
320           Foo over UDP allows any IP protocol to be directly encapsulated
321           over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
322           network mechanisms and optimizations for UDP (such as ECMP
323           and RSS) can be leveraged to provide better service.
326         bool "IP: FOU encapsulation of IP tunnels"
327         depends on NET_IPIP || NET_IPGRE || IPV6_SIT
328         select NET_FOU
329         ---help---
330           Allow configuration of FOU or GUE encapsulation for IP tunnels.
331           When this option is enabled IP tunnels can be configured to use
332           FOU or GUE encapsulation.
334 config INET_AH
335         tristate "IP: AH transformation"
336         select XFRM_ALGO
337         select CRYPTO
338         select CRYPTO_HMAC
339         select CRYPTO_MD5
340         select CRYPTO_SHA1
341         ---help---
342           Support for IPsec AH.
344           If unsure, say Y.
346 config INET_ESP
347         tristate "IP: ESP transformation"
348         select XFRM_ALGO
349         select CRYPTO
350         select CRYPTO_AUTHENC
351         select CRYPTO_HMAC
352         select CRYPTO_MD5
353         select CRYPTO_CBC
354         select CRYPTO_SHA1
355         select CRYPTO_DES
356         select CRYPTO_ECHAINIV
357         ---help---
358           Support for IPsec ESP.
360           If unsure, say Y.
362 config INET_IPCOMP
363         tristate "IP: IPComp transformation"
364         select INET_XFRM_TUNNEL
365         select XFRM_IPCOMP
366         ---help---
367           Support for IP Payload Compression Protocol (IPComp) (RFC3173),
368           typically needed for IPsec.
370           If unsure, say Y.
373         tristate
374         select INET_TUNNEL
375         default n
377 config INET_TUNNEL
378         tristate
379         default n
382         tristate "IP: IPsec transport mode"
383         default y
384         select XFRM
385         ---help---
386           Support for IPsec transport mode.
388           If unsure, say Y.
391         tristate "IP: IPsec tunnel mode"
392         default y
393         select XFRM
394         ---help---
395           Support for IPsec tunnel mode.
397           If unsure, say Y.
400         tristate "IP: IPsec BEET mode"
401         default y
402         select XFRM
403         ---help---
404           Support for IPsec BEET mode.
406           If unsure, say Y.
408 config INET_LRO
409         tristate "Large Receive Offload (ipv4/tcp)"
410         default y
411         ---help---
412           Support for Large Receive Offload (ipv4/tcp).
414           If unsure, say Y.
416 config INET_DIAG
417         tristate "INET: socket monitoring interface"
418         default y
419         ---help---
420           Support for INET (TCP, DCCP, etc) socket monitoring interface used by
421           native Linux tools such as ss. ss is included in iproute2, currently
422           downloadable at:
426           If unsure, say Y.
428 config INET_TCP_DIAG
429         depends on INET_DIAG
430         def_tristate INET_DIAG
432 config INET_UDP_DIAG
433         tristate "UDP: socket monitoring interface"
434         depends on INET_DIAG && (IPV6 || IPV6=n)
435         default n
436         ---help---
437           Support for UDP socket monitoring interface used by the ss tool.
438           If unsure, say Y.
441         bool "INET: allow privileged process to administratively close sockets"
442         depends on INET_DIAG
443         default n
444         ---help---
445           Provides a SOCK_DESTROY operation that allows privileged processes
446           (e.g., a connection manager or a network administration tool such as
447           ss) to close sockets opened by other processes. Closing a socket in
448           this way interrupts any blocking read/write/connect operations on
449           the socket and causes future socket calls to behave as if the socket
450           had been disconnected.
451           If unsure, say N.
453 menuconfig TCP_CONG_ADVANCED
454         bool "TCP: advanced congestion control"
455         ---help---
456           Support for selection of various TCP congestion control
457           modules.
459           Nearly all users can safely say no here, and a safe default
460           selection will be made (CUBIC with new Reno as a fallback).
462           If unsure, say N.
466 config TCP_CONG_BIC
467         tristate "Binary Increase Congestion (BIC) control"
468         default m
469         ---help---
470         BIC-TCP is a sender-side only change that ensures a linear RTT
471         fairness under large windows while offering both scalability and
472         bounded TCP-friendliness. The protocol combines two schemes
473         called additive increase and binary search increase. When the
474         congestion window is large, additive increase with a large
475         increment ensures linear RTT fairness as well as good
476         scalability. Under small congestion windows, binary search
477         increase provides TCP friendliness.
478         See
480 config TCP_CONG_CUBIC
481         tristate "CUBIC TCP"
482         default y
483         ---help---
484         This is version 2.0 of BIC-TCP which uses a cubic growth function
485         among other techniques.
486         See
489         tristate "TCP Westwood+"
490         default m
491         ---help---
492         TCP Westwood+ is a sender-side only modification of the TCP Reno
493         protocol stack that optimizes the performance of TCP congestion
494         control. It is based on end-to-end bandwidth estimation to set
495         congestion window and slow start threshold after a congestion
496         episode. Using this estimation, TCP Westwood+ adaptively sets a
497         slow start threshold and a congestion window which takes into
498         account the bandwidth used  at the time congestion is experienced.
499         TCP Westwood+ significantly increases fairness wrt TCP Reno in
500         wired networks and throughput over wireless links.
502 config TCP_CONG_HTCP
503         tristate "H-TCP"
504         default m
505         ---help---
506         H-TCP is a send-side only modifications of the TCP Reno
507         protocol stack that optimizes the performance of TCP
508         congestion control for high speed network links. It uses a
509         modeswitch to change the alpha and beta parameters of TCP Reno
510         based on network conditions and in a way so as to be fair with
511         other Reno and H-TCP flows.
513 config TCP_CONG_HSTCP
514         tristate "High Speed TCP"
515         default n
516         ---help---
517         Sally Floyd's High Speed TCP (RFC 3649) congestion control.
518         A modification to TCP's congestion control mechanism for use
519         with large congestion windows. A table indicates how much to
520         increase the congestion window by when an ACK is received.
521         For more detail see
523 config TCP_CONG_HYBLA
524         tristate "TCP-Hybla congestion control algorithm"
525         default n
526         ---help---
527         TCP-Hybla is a sender-side only change that eliminates penalization of
528         long-RTT, large-bandwidth connections, like when satellite legs are
529         involved, especially when sharing a common bottleneck with normal
530         terrestrial connections.
532 config TCP_CONG_VEGAS
533         tristate "TCP Vegas"
534         default n
535         ---help---
536         TCP Vegas is a sender-side only change to TCP that anticipates
537         the onset of congestion by estimating the bandwidth. TCP Vegas
538         adjusts the sending rate by modifying the congestion
539         window. TCP Vegas should provide less packet loss, but it is
540         not as aggressive as TCP Reno.
543         tristate "Scalable TCP"
544         default n
545         ---help---
546         Scalable TCP is a sender-side only change to TCP which uses a
547         MIMD congestion control algorithm which has some nice scaling
548         properties, though is known to have fairness issues.
549         See
551 config TCP_CONG_LP
552         tristate "TCP Low Priority"
553         default n
554         ---help---
555         TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
556         to utilize only the excess network bandwidth as compared to the
557         ``fair share`` of bandwidth as targeted by TCP.
558         See
560 config TCP_CONG_VENO
561         tristate "TCP Veno"
562         default n
563         ---help---
564         TCP Veno is a sender-side only enhancement of TCP to obtain better
565         throughput over wireless networks. TCP Veno makes use of state
566         distinguishing to circumvent the difficult judgment of the packet loss
567         type. TCP Veno cuts down less congestion window in response to random
568         loss packets.
569         See <> 
571 config TCP_CONG_YEAH
572         tristate "YeAH TCP"
573         select TCP_CONG_VEGAS
574         default n
575         ---help---
576         YeAH-TCP is a sender-side high-speed enabled TCP congestion control
577         algorithm, which uses a mixed loss/delay approach to compute the
578         congestion window. It's design goals target high efficiency,
579         internal, RTT and Reno fairness, resilience to link loss while
580         keeping network elements load as low as possible.
582         For further details look here:
586         tristate "TCP Illinois"
587         default n
588         ---help---
589         TCP-Illinois is a sender-side modification of TCP Reno for
590         high speed long delay links. It uses round-trip-time to
591         adjust the alpha and beta parameters to achieve a higher average
592         throughput and maintain fairness.
594         For further details see:
597 config TCP_CONG_DCTCP
598         tristate "DataCenter TCP (DCTCP)"
599         default n
600         ---help---
601         DCTCP leverages Explicit Congestion Notification (ECN) in the network to
602         provide multi-bit feedback to the end hosts. It is designed to provide:
604         - High burst tolerance (incast due to partition/aggregate),
605         - Low latency (short flows, queries),
606         - High throughput (continuous data updates, large file transfers) with
607           commodity, shallow-buffered switches.
609         All switches in the data center network running DCTCP must support
610         ECN marking and be configured for marking when reaching defined switch
611         buffer thresholds. The default ECN marking threshold heuristic for
612         DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
613         (~100KB) at 10Gbps, but might need further careful tweaking.
615         For further details see:
618 config TCP_CONG_CDG
619         tristate "CAIA Delay-Gradient (CDG)"
620         default n
621         ---help---
622         CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
623         the TCP sender in order to:
625           o Use the delay gradient as a congestion signal.
626           o Back off with an average probability that is independent of the RTT.
627           o Coexist with flows that use loss-based congestion control.
628           o Tolerate packet loss unrelated to congestion.
630         For further details see:
631           D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
632           delay gradients." In Networking 2011. Preprint:
634 choice
635         prompt "Default TCP congestion control"
636         default DEFAULT_CUBIC
637         help
638           Select the TCP congestion control that will be used by default
639           for all connections.
641         config DEFAULT_BIC
642                 bool "Bic" if TCP_CONG_BIC=y
644         config DEFAULT_CUBIC
645                 bool "Cubic" if TCP_CONG_CUBIC=y
647         config DEFAULT_HTCP
648                 bool "Htcp" if TCP_CONG_HTCP=y
650         config DEFAULT_HYBLA
651                 bool "Hybla" if TCP_CONG_HYBLA=y
653         config DEFAULT_VEGAS
654                 bool "Vegas" if TCP_CONG_VEGAS=y
656         config DEFAULT_VENO
657                 bool "Veno" if TCP_CONG_VENO=y
659         config DEFAULT_WESTWOOD
660                 bool "Westwood" if TCP_CONG_WESTWOOD=y
662         config DEFAULT_DCTCP
663                 bool "DCTCP" if TCP_CONG_DCTCP=y
665         config DEFAULT_CDG
666                 bool "CDG" if TCP_CONG_CDG=y
668         config DEFAULT_RENO
669                 bool "Reno"
670 endchoice
672 endif
674 config TCP_CONG_CUBIC
675         tristate
676         depends on !TCP_CONG_ADVANCED
677         default y
680         string
681         default "bic" if DEFAULT_BIC
682         default "cubic" if DEFAULT_CUBIC
683         default "htcp" if DEFAULT_HTCP
684         default "hybla" if DEFAULT_HYBLA
685         default "vegas" if DEFAULT_VEGAS
686         default "westwood" if DEFAULT_WESTWOOD
687         default "veno" if DEFAULT_VENO
688         default "reno" if DEFAULT_RENO
689         default "dctcp" if DEFAULT_DCTCP
690         default "cdg" if DEFAULT_CDG
691         default "cubic"
693 config TCP_MD5SIG
694         bool "TCP: MD5 Signature Option support (RFC2385)"
695         select CRYPTO
696         select CRYPTO_MD5
697         ---help---
698           RFC2385 specifies a method of giving MD5 protection to TCP sessions.
699           Its main (only?) use is to protect BGP sessions between core routers
700           on the Internet.
702           If unsure, say N.

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