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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         select DST_CACHE
190         default n
192 config 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.
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.
216 config IP_MROUTE
217         bool "IP: multicast routing"
218         depends on IP_MULTICAST
219         help
220           This is used if you want your machine to act as a router for IP
221           packets that have several destination addresses. It is needed on the
222           MBONE, a high bandwidth network on top of the Internet which carries
223           audio and video broadcasts. In order to do that, you would most
224           likely run the program mrouted. If you haven't heard about it, you
225           don't need it.
228         bool "IP: multicast policy routing"
229         depends on IP_MROUTE && IP_ADVANCED_ROUTER
230         select FIB_RULES
231         help
232           Normally, a multicast router runs a userspace daemon and decides
233           what to do with a multicast packet based on the source and
234           destination addresses. If you say Y here, the multicast router
235           will also be able to take interfaces and packet marks into
236           account and run multiple instances of userspace daemons
237           simultaneously, each one handling a single table.
239           If unsure, say N.
241 config IP_PIMSM_V1
242         bool "IP: PIM-SM version 1 support"
243         depends on IP_MROUTE
244         help
245           Kernel side support for Sparse Mode PIM (Protocol Independent
246           Multicast) version 1. This multicast routing protocol is used widely
247           because Cisco supports it. You need special software to use it
248           (pimd-v1). Please see <> for more
249           information about PIM.
251           Say Y if you want to use PIM-SM v1. Note that you can say N here if
252           you just want to use Dense Mode PIM.
254 config IP_PIMSM_V2
255         bool "IP: PIM-SM version 2 support"
256         depends on IP_MROUTE
257         help
258           Kernel side support for Sparse Mode PIM version 2. In order to use
259           this, you need an experimental routing daemon supporting it (pimd or
260           gated-5). This routing protocol is not used widely, so say N unless
261           you want to play with it.
263 config SYN_COOKIES
264         bool "IP: TCP syncookie support"
265         ---help---
266           Normal TCP/IP networking is open to an attack known as "SYN
267           flooding". This denial-of-service attack prevents legitimate remote
268           users from being able to connect to your computer during an ongoing
269           attack and requires very little work from the attacker, who can
270           operate from anywhere on the Internet.
272           SYN cookies provide protection against this type of attack. If you
273           say Y here, the TCP/IP stack will use a cryptographic challenge
274           protocol known as "SYN cookies" to enable legitimate users to
275           continue to connect, even when your machine is under attack. There
276           is no need for the legitimate users to change their TCP/IP software;
277           SYN cookies work transparently to them. For technical information
278           about SYN cookies, check out <>.
280           If you are SYN flooded, the source address reported by the kernel is
281           likely to have been forged by the attacker; it is only reported as
282           an aid in tracing the packets to their actual source and should not
283           be taken as absolute truth.
285           SYN cookies may prevent correct error reporting on clients when the
286           server is really overloaded. If this happens frequently better turn
287           them off.
289           If you say Y here, you can disable SYN cookies at run time by
290           saying Y to "/proc file system support" and
291           "Sysctl support" below and executing the command
293           echo 0 > /proc/sys/net/ipv4/tcp_syncookies
295           after the /proc file system has been mounted.
297           If unsure, say N.
299 config NET_IPVTI
300         tristate "Virtual (secure) IP: tunneling"
301         select INET_TUNNEL
302         select NET_IP_TUNNEL
303         depends on INET_XFRM_MODE_TUNNEL
304         ---help---
305           Tunneling means encapsulating data of one protocol type within
306           another protocol and sending it over a channel that understands the
307           encapsulating protocol. This can be used with xfrm mode tunnel to give
308           the notion of a secure tunnel for IPSEC and then use routing protocol
309           on top.
311 config NET_UDP_TUNNEL
312         tristate
313         select NET_IP_TUNNEL
314         default n
316 config NET_FOU
317         tristate "IP: Foo (IP protocols) over UDP"
318         select XFRM
319         select NET_UDP_TUNNEL
320         ---help---
321           Foo over UDP allows any IP protocol to be directly encapsulated
322           over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
323           network mechanisms and optimizations for UDP (such as ECMP
324           and RSS) can be leveraged to provide better service.
327         bool "IP: FOU encapsulation of IP tunnels"
328         depends on NET_IPIP || NET_IPGRE || IPV6_SIT
329         select NET_FOU
330         ---help---
331           Allow configuration of FOU or GUE encapsulation for IP tunnels.
332           When this option is enabled IP tunnels can be configured to use
333           FOU or GUE encapsulation.
335 config INET_AH
336         tristate "IP: AH transformation"
337         select XFRM_ALGO
338         select CRYPTO
339         select CRYPTO_HMAC
340         select CRYPTO_MD5
341         select CRYPTO_SHA1
342         ---help---
343           Support for IPsec AH.
345           If unsure, say Y.
347 config INET_ESP
348         tristate "IP: ESP transformation"
349         select XFRM_ALGO
350         select CRYPTO
351         select CRYPTO_AUTHENC
352         select CRYPTO_HMAC
353         select CRYPTO_MD5
354         select CRYPTO_CBC
355         select CRYPTO_SHA1
356         select CRYPTO_DES
357         select CRYPTO_ECHAINIV
358         ---help---
359           Support for IPsec ESP.
361           If unsure, say Y.
363 config INET_IPCOMP
364         tristate "IP: IPComp transformation"
365         select INET_XFRM_TUNNEL
366         select XFRM_IPCOMP
367         ---help---
368           Support for IP Payload Compression Protocol (IPComp) (RFC3173),
369           typically needed for IPsec.
371           If unsure, say Y.
374         tristate
375         select INET_TUNNEL
376         default n
378 config INET_TUNNEL
379         tristate
380         default n
383         tristate "IP: IPsec transport mode"
384         default y
385         select XFRM
386         ---help---
387           Support for IPsec transport mode.
389           If unsure, say Y.
392         tristate "IP: IPsec tunnel mode"
393         default y
394         select XFRM
395         ---help---
396           Support for IPsec tunnel mode.
398           If unsure, say Y.
401         tristate "IP: IPsec BEET mode"
402         default y
403         select XFRM
404         ---help---
405           Support for IPsec BEET mode.
407           If unsure, say Y.
409 config INET_DIAG
410         tristate "INET: socket monitoring interface"
411         default y
412         ---help---
413           Support for INET (TCP, DCCP, etc) socket monitoring interface used by
414           native Linux tools such as ss. ss is included in iproute2, currently
415           downloadable at:
419           If unsure, say Y.
421 config INET_TCP_DIAG
422         depends on INET_DIAG
423         def_tristate INET_DIAG
425 config INET_UDP_DIAG
426         tristate "UDP: socket monitoring interface"
427         depends on INET_DIAG && (IPV6 || IPV6=n)
428         default n
429         ---help---
430           Support for UDP socket monitoring interface used by the ss tool.
431           If unsure, say Y.
434         bool "INET: allow privileged process to administratively close sockets"
435         depends on INET_DIAG
436         default n
437         ---help---
438           Provides a SOCK_DESTROY operation that allows privileged processes
439           (e.g., a connection manager or a network administration tool such as
440           ss) to close sockets opened by other processes. Closing a socket in
441           this way interrupts any blocking read/write/connect operations on
442           the socket and causes future socket calls to behave as if the socket
443           had been disconnected.
444           If unsure, say N.
446 menuconfig TCP_CONG_ADVANCED
447         bool "TCP: advanced congestion control"
448         ---help---
449           Support for selection of various TCP congestion control
450           modules.
452           Nearly all users can safely say no here, and a safe default
453           selection will be made (CUBIC with new Reno as a fallback).
455           If unsure, say N.
459 config TCP_CONG_BIC
460         tristate "Binary Increase Congestion (BIC) control"
461         default m
462         ---help---
463         BIC-TCP is a sender-side only change that ensures a linear RTT
464         fairness under large windows while offering both scalability and
465         bounded TCP-friendliness. The protocol combines two schemes
466         called additive increase and binary search increase. When the
467         congestion window is large, additive increase with a large
468         increment ensures linear RTT fairness as well as good
469         scalability. Under small congestion windows, binary search
470         increase provides TCP friendliness.
471         See
473 config TCP_CONG_CUBIC
474         tristate "CUBIC TCP"
475         default y
476         ---help---
477         This is version 2.0 of BIC-TCP which uses a cubic growth function
478         among other techniques.
479         See
482         tristate "TCP Westwood+"
483         default m
484         ---help---
485         TCP Westwood+ is a sender-side only modification of the TCP Reno
486         protocol stack that optimizes the performance of TCP congestion
487         control. It is based on end-to-end bandwidth estimation to set
488         congestion window and slow start threshold after a congestion
489         episode. Using this estimation, TCP Westwood+ adaptively sets a
490         slow start threshold and a congestion window which takes into
491         account the bandwidth used  at the time congestion is experienced.
492         TCP Westwood+ significantly increases fairness wrt TCP Reno in
493         wired networks and throughput over wireless links.
495 config TCP_CONG_HTCP
496         tristate "H-TCP"
497         default m
498         ---help---
499         H-TCP is a send-side only modifications of the TCP Reno
500         protocol stack that optimizes the performance of TCP
501         congestion control for high speed network links. It uses a
502         modeswitch to change the alpha and beta parameters of TCP Reno
503         based on network conditions and in a way so as to be fair with
504         other Reno and H-TCP flows.
506 config TCP_CONG_HSTCP
507         tristate "High Speed TCP"
508         default n
509         ---help---
510         Sally Floyd's High Speed TCP (RFC 3649) congestion control.
511         A modification to TCP's congestion control mechanism for use
512         with large congestion windows. A table indicates how much to
513         increase the congestion window by when an ACK is received.
514         For more detail see
516 config TCP_CONG_HYBLA
517         tristate "TCP-Hybla congestion control algorithm"
518         default n
519         ---help---
520         TCP-Hybla is a sender-side only change that eliminates penalization of
521         long-RTT, large-bandwidth connections, like when satellite legs are
522         involved, especially when sharing a common bottleneck with normal
523         terrestrial connections.
525 config TCP_CONG_VEGAS
526         tristate "TCP Vegas"
527         default n
528         ---help---
529         TCP Vegas is a sender-side only change to TCP that anticipates
530         the onset of congestion by estimating the bandwidth. TCP Vegas
531         adjusts the sending rate by modifying the congestion
532         window. TCP Vegas should provide less packet loss, but it is
533         not as aggressive as TCP Reno.
536         tristate "Scalable TCP"
537         default n
538         ---help---
539         Scalable TCP is a sender-side only change to TCP which uses a
540         MIMD congestion control algorithm which has some nice scaling
541         properties, though is known to have fairness issues.
542         See
544 config TCP_CONG_LP
545         tristate "TCP Low Priority"
546         default n
547         ---help---
548         TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
549         to utilize only the excess network bandwidth as compared to the
550         ``fair share`` of bandwidth as targeted by TCP.
551         See
553 config TCP_CONG_VENO
554         tristate "TCP Veno"
555         default n
556         ---help---
557         TCP Veno is a sender-side only enhancement of TCP to obtain better
558         throughput over wireless networks. TCP Veno makes use of state
559         distinguishing to circumvent the difficult judgment of the packet loss
560         type. TCP Veno cuts down less congestion window in response to random
561         loss packets.
562         See <> 
564 config TCP_CONG_YEAH
565         tristate "YeAH TCP"
566         select TCP_CONG_VEGAS
567         default n
568         ---help---
569         YeAH-TCP is a sender-side high-speed enabled TCP congestion control
570         algorithm, which uses a mixed loss/delay approach to compute the
571         congestion window. It's design goals target high efficiency,
572         internal, RTT and Reno fairness, resilience to link loss while
573         keeping network elements load as low as possible.
575         For further details look here:
579         tristate "TCP Illinois"
580         default n
581         ---help---
582         TCP-Illinois is a sender-side modification of TCP Reno for
583         high speed long delay links. It uses round-trip-time to
584         adjust the alpha and beta parameters to achieve a higher average
585         throughput and maintain fairness.
587         For further details see:
590 config TCP_CONG_DCTCP
591         tristate "DataCenter TCP (DCTCP)"
592         default n
593         ---help---
594         DCTCP leverages Explicit Congestion Notification (ECN) in the network to
595         provide multi-bit feedback to the end hosts. It is designed to provide:
597         - High burst tolerance (incast due to partition/aggregate),
598         - Low latency (short flows, queries),
599         - High throughput (continuous data updates, large file transfers) with
600           commodity, shallow-buffered switches.
602         All switches in the data center network running DCTCP must support
603         ECN marking and be configured for marking when reaching defined switch
604         buffer thresholds. The default ECN marking threshold heuristic for
605         DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
606         (~100KB) at 10Gbps, but might need further careful tweaking.
608         For further details see:
611 config TCP_CONG_CDG
612         tristate "CAIA Delay-Gradient (CDG)"
613         default n
614         ---help---
615         CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
616         the TCP sender in order to:
618           o Use the delay gradient as a congestion signal.
619           o Back off with an average probability that is independent of the RTT.
620           o Coexist with flows that use loss-based congestion control.
621           o Tolerate packet loss unrelated to congestion.
623         For further details see:
624           D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
625           delay gradients." In Networking 2011. Preprint:
627 choice
628         prompt "Default TCP congestion control"
629         default DEFAULT_CUBIC
630         help
631           Select the TCP congestion control that will be used by default
632           for all connections.
634         config DEFAULT_BIC
635                 bool "Bic" if TCP_CONG_BIC=y
637         config DEFAULT_CUBIC
638                 bool "Cubic" if TCP_CONG_CUBIC=y
640         config DEFAULT_HTCP
641                 bool "Htcp" if TCP_CONG_HTCP=y
643         config DEFAULT_HYBLA
644                 bool "Hybla" if TCP_CONG_HYBLA=y
646         config DEFAULT_VEGAS
647                 bool "Vegas" if TCP_CONG_VEGAS=y
649         config DEFAULT_VENO
650                 bool "Veno" if TCP_CONG_VENO=y
652         config DEFAULT_WESTWOOD
653                 bool "Westwood" if TCP_CONG_WESTWOOD=y
655         config DEFAULT_DCTCP
656                 bool "DCTCP" if TCP_CONG_DCTCP=y
658         config DEFAULT_CDG
659                 bool "CDG" if TCP_CONG_CDG=y
661         config DEFAULT_RENO
662                 bool "Reno"
663 endchoice
665 endif
667 config TCP_CONG_CUBIC
668         tristate
669         depends on !TCP_CONG_ADVANCED
670         default y
673         string
674         default "bic" if DEFAULT_BIC
675         default "cubic" if DEFAULT_CUBIC
676         default "htcp" if DEFAULT_HTCP
677         default "hybla" if DEFAULT_HYBLA
678         default "vegas" if DEFAULT_VEGAS
679         default "westwood" if DEFAULT_WESTWOOD
680         default "veno" if DEFAULT_VENO
681         default "reno" if DEFAULT_RENO
682         default "dctcp" if DEFAULT_DCTCP
683         default "cdg" if DEFAULT_CDG
684         default "cubic"
686 config TCP_MD5SIG
687         bool "TCP: MD5 Signature Option support (RFC2385)"
688         select CRYPTO
689         select CRYPTO_MD5
690         ---help---
691           RFC2385 specifies a method of giving MD5 protection to TCP sessions.
692           Its main (only?) use is to protect BGP sessions between core routers
693           on the Internet.
695           If unsure, say N.

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