Linux kernel mirror (for testing)
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kernel
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linux
1#
2# IP configuration
3#
4config 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 <http://www.savetz.com/mbone/>. For most people, it's safe to say N.
13
14config IP_ADVANCED_ROUTER
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.
21
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.
25
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
30
31 echo "1" > /proc/sys/net/ipv4/ip_forward
32
33 at boot time after the /proc file system has been mounted.
34
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:
44
45 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
46 or
47 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
48
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>.
52
53 If unsure, say N here.
54
55config 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.
61
62config IP_MULTIPLE_TABLES
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.
72
73 If you are interested in this, please see the preliminary
74 documentation at <http://www.compendium.com.ar/policy-routing.txt>
75 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>.
76 You will need supporting software from
77 <ftp://ftp.tux.org/pub/net/ip-routing/>.
78
79 If unsure, say N.
80
81config IP_ROUTE_MULTIPATH
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.
92
93config IP_ROUTE_VERBOSE
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").
103
104config IP_ROUTE_CLASSID
105 bool
106
107config 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.
117
118config 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.
130
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.
134
135config 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.
149
150config 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.
162
163config 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).
176
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.
180
181config 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.
186
187config NET_IP_TUNNEL
188 tristate
189 default n
190
191config 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.
205
206config NET_IPGRE_BROADCAST
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.
214
215config 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.
225
226config IP_MROUTE_MULTIPLE_TABLES
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.
237
238 If unsure, say N.
239
240config 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 <http://netweb.usc.edu/pim/> for more
248 information about PIM.
249
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.
252
253config 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.
261
262config ARPD
263 bool "IP: ARP daemon support"
264 ---help---
265 The kernel maintains an internal cache which maps IP addresses to
266 hardware addresses on the local network, so that Ethernet
267 frames are sent to the proper address on the physical networking
268 layer. Normally, kernel uses the ARP protocol to resolve these
269 mappings.
270
271 Saying Y here adds support to have an user space daemon to do this
272 resolution instead. This is useful for implementing an alternate
273 address resolution protocol (e.g. NHRP on mGRE tunnels) and also for
274 testing purposes.
275
276 If unsure, say N.
277
278config SYN_COOKIES
279 bool "IP: TCP syncookie support"
280 ---help---
281 Normal TCP/IP networking is open to an attack known as "SYN
282 flooding". This denial-of-service attack prevents legitimate remote
283 users from being able to connect to your computer during an ongoing
284 attack and requires very little work from the attacker, who can
285 operate from anywhere on the Internet.
286
287 SYN cookies provide protection against this type of attack. If you
288 say Y here, the TCP/IP stack will use a cryptographic challenge
289 protocol known as "SYN cookies" to enable legitimate users to
290 continue to connect, even when your machine is under attack. There
291 is no need for the legitimate users to change their TCP/IP software;
292 SYN cookies work transparently to them. For technical information
293 about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
294
295 If you are SYN flooded, the source address reported by the kernel is
296 likely to have been forged by the attacker; it is only reported as
297 an aid in tracing the packets to their actual source and should not
298 be taken as absolute truth.
299
300 SYN cookies may prevent correct error reporting on clients when the
301 server is really overloaded. If this happens frequently better turn
302 them off.
303
304 If you say Y here, you can disable SYN cookies at run time by
305 saying Y to "/proc file system support" and
306 "Sysctl support" below and executing the command
307
308 echo 0 > /proc/sys/net/ipv4/tcp_syncookies
309
310 after the /proc file system has been mounted.
311
312 If unsure, say N.
313
314config NET_IPVTI
315 tristate "Virtual (secure) IP: tunneling"
316 select INET_TUNNEL
317 select NET_IP_TUNNEL
318 depends on INET_XFRM_MODE_TUNNEL
319 ---help---
320 Tunneling means encapsulating data of one protocol type within
321 another protocol and sending it over a channel that understands the
322 encapsulating protocol. This can be used with xfrm mode tunnel to give
323 the notion of a secure tunnel for IPSEC and then use routing protocol
324 on top.
325
326config INET_AH
327 tristate "IP: AH transformation"
328 select XFRM_ALGO
329 select CRYPTO
330 select CRYPTO_HMAC
331 select CRYPTO_MD5
332 select CRYPTO_SHA1
333 ---help---
334 Support for IPsec AH.
335
336 If unsure, say Y.
337
338config INET_ESP
339 tristate "IP: ESP transformation"
340 select XFRM_ALGO
341 select CRYPTO
342 select CRYPTO_AUTHENC
343 select CRYPTO_HMAC
344 select CRYPTO_MD5
345 select CRYPTO_CBC
346 select CRYPTO_SHA1
347 select CRYPTO_DES
348 ---help---
349 Support for IPsec ESP.
350
351 If unsure, say Y.
352
353config INET_IPCOMP
354 tristate "IP: IPComp transformation"
355 select INET_XFRM_TUNNEL
356 select XFRM_IPCOMP
357 ---help---
358 Support for IP Payload Compression Protocol (IPComp) (RFC3173),
359 typically needed for IPsec.
360
361 If unsure, say Y.
362
363config INET_XFRM_TUNNEL
364 tristate
365 select INET_TUNNEL
366 default n
367
368config INET_TUNNEL
369 tristate
370 default n
371
372config INET_XFRM_MODE_TRANSPORT
373 tristate "IP: IPsec transport mode"
374 default y
375 select XFRM
376 ---help---
377 Support for IPsec transport mode.
378
379 If unsure, say Y.
380
381config INET_XFRM_MODE_TUNNEL
382 tristate "IP: IPsec tunnel mode"
383 default y
384 select XFRM
385 ---help---
386 Support for IPsec tunnel mode.
387
388 If unsure, say Y.
389
390config INET_XFRM_MODE_BEET
391 tristate "IP: IPsec BEET mode"
392 default y
393 select XFRM
394 ---help---
395 Support for IPsec BEET mode.
396
397 If unsure, say Y.
398
399config INET_LRO
400 tristate "Large Receive Offload (ipv4/tcp)"
401 default y
402 ---help---
403 Support for Large Receive Offload (ipv4/tcp).
404
405 If unsure, say Y.
406
407config INET_DIAG
408 tristate "INET: socket monitoring interface"
409 default y
410 ---help---
411 Support for INET (TCP, DCCP, etc) socket monitoring interface used by
412 native Linux tools such as ss. ss is included in iproute2, currently
413 downloadable at:
414
415 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
416
417 If unsure, say Y.
418
419config INET_TCP_DIAG
420 depends on INET_DIAG
421 def_tristate INET_DIAG
422
423config INET_UDP_DIAG
424 tristate "UDP: socket monitoring interface"
425 depends on INET_DIAG && (IPV6 || IPV6=n)
426 default n
427 ---help---
428 Support for UDP socket monitoring interface used by the ss tool.
429 If unsure, say Y.
430
431menuconfig TCP_CONG_ADVANCED
432 bool "TCP: advanced congestion control"
433 ---help---
434 Support for selection of various TCP congestion control
435 modules.
436
437 Nearly all users can safely say no here, and a safe default
438 selection will be made (CUBIC with new Reno as a fallback).
439
440 If unsure, say N.
441
442if TCP_CONG_ADVANCED
443
444config TCP_CONG_BIC
445 tristate "Binary Increase Congestion (BIC) control"
446 default m
447 ---help---
448 BIC-TCP is a sender-side only change that ensures a linear RTT
449 fairness under large windows while offering both scalability and
450 bounded TCP-friendliness. The protocol combines two schemes
451 called additive increase and binary search increase. When the
452 congestion window is large, additive increase with a large
453 increment ensures linear RTT fairness as well as good
454 scalability. Under small congestion windows, binary search
455 increase provides TCP friendliness.
456 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
457
458config TCP_CONG_CUBIC
459 tristate "CUBIC TCP"
460 default y
461 ---help---
462 This is version 2.0 of BIC-TCP which uses a cubic growth function
463 among other techniques.
464 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
465
466config TCP_CONG_WESTWOOD
467 tristate "TCP Westwood+"
468 default m
469 ---help---
470 TCP Westwood+ is a sender-side only modification of the TCP Reno
471 protocol stack that optimizes the performance of TCP congestion
472 control. It is based on end-to-end bandwidth estimation to set
473 congestion window and slow start threshold after a congestion
474 episode. Using this estimation, TCP Westwood+ adaptively sets a
475 slow start threshold and a congestion window which takes into
476 account the bandwidth used at the time congestion is experienced.
477 TCP Westwood+ significantly increases fairness wrt TCP Reno in
478 wired networks and throughput over wireless links.
479
480config TCP_CONG_HTCP
481 tristate "H-TCP"
482 default m
483 ---help---
484 H-TCP is a send-side only modifications of the TCP Reno
485 protocol stack that optimizes the performance of TCP
486 congestion control for high speed network links. It uses a
487 modeswitch to change the alpha and beta parameters of TCP Reno
488 based on network conditions and in a way so as to be fair with
489 other Reno and H-TCP flows.
490
491config TCP_CONG_HSTCP
492 tristate "High Speed TCP"
493 default n
494 ---help---
495 Sally Floyd's High Speed TCP (RFC 3649) congestion control.
496 A modification to TCP's congestion control mechanism for use
497 with large congestion windows. A table indicates how much to
498 increase the congestion window by when an ACK is received.
499 For more detail see http://www.icir.org/floyd/hstcp.html
500
501config TCP_CONG_HYBLA
502 tristate "TCP-Hybla congestion control algorithm"
503 default n
504 ---help---
505 TCP-Hybla is a sender-side only change that eliminates penalization of
506 long-RTT, large-bandwidth connections, like when satellite legs are
507 involved, especially when sharing a common bottleneck with normal
508 terrestrial connections.
509
510config TCP_CONG_VEGAS
511 tristate "TCP Vegas"
512 default n
513 ---help---
514 TCP Vegas is a sender-side only change to TCP that anticipates
515 the onset of congestion by estimating the bandwidth. TCP Vegas
516 adjusts the sending rate by modifying the congestion
517 window. TCP Vegas should provide less packet loss, but it is
518 not as aggressive as TCP Reno.
519
520config TCP_CONG_SCALABLE
521 tristate "Scalable TCP"
522 default n
523 ---help---
524 Scalable TCP is a sender-side only change to TCP which uses a
525 MIMD congestion control algorithm which has some nice scaling
526 properties, though is known to have fairness issues.
527 See http://www.deneholme.net/tom/scalable/
528
529config TCP_CONG_LP
530 tristate "TCP Low Priority"
531 default n
532 ---help---
533 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
534 to utilize only the excess network bandwidth as compared to the
535 ``fair share`` of bandwidth as targeted by TCP.
536 See http://www-ece.rice.edu/networks/TCP-LP/
537
538config TCP_CONG_VENO
539 tristate "TCP Veno"
540 default n
541 ---help---
542 TCP Veno is a sender-side only enhancement of TCP to obtain better
543 throughput over wireless networks. TCP Veno makes use of state
544 distinguishing to circumvent the difficult judgment of the packet loss
545 type. TCP Veno cuts down less congestion window in response to random
546 loss packets.
547 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
548
549config TCP_CONG_YEAH
550 tristate "YeAH TCP"
551 select TCP_CONG_VEGAS
552 default n
553 ---help---
554 YeAH-TCP is a sender-side high-speed enabled TCP congestion control
555 algorithm, which uses a mixed loss/delay approach to compute the
556 congestion window. It's design goals target high efficiency,
557 internal, RTT and Reno fairness, resilience to link loss while
558 keeping network elements load as low as possible.
559
560 For further details look here:
561 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
562
563config TCP_CONG_ILLINOIS
564 tristate "TCP Illinois"
565 default n
566 ---help---
567 TCP-Illinois is a sender-side modification of TCP Reno for
568 high speed long delay links. It uses round-trip-time to
569 adjust the alpha and beta parameters to achieve a higher average
570 throughput and maintain fairness.
571
572 For further details see:
573 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
574
575choice
576 prompt "Default TCP congestion control"
577 default DEFAULT_CUBIC
578 help
579 Select the TCP congestion control that will be used by default
580 for all connections.
581
582 config DEFAULT_BIC
583 bool "Bic" if TCP_CONG_BIC=y
584
585 config DEFAULT_CUBIC
586 bool "Cubic" if TCP_CONG_CUBIC=y
587
588 config DEFAULT_HTCP
589 bool "Htcp" if TCP_CONG_HTCP=y
590
591 config DEFAULT_HYBLA
592 bool "Hybla" if TCP_CONG_HYBLA=y
593
594 config DEFAULT_VEGAS
595 bool "Vegas" if TCP_CONG_VEGAS=y
596
597 config DEFAULT_VENO
598 bool "Veno" if TCP_CONG_VENO=y
599
600 config DEFAULT_WESTWOOD
601 bool "Westwood" if TCP_CONG_WESTWOOD=y
602
603 config DEFAULT_RENO
604 bool "Reno"
605
606endchoice
607
608endif
609
610config TCP_CONG_CUBIC
611 tristate
612 depends on !TCP_CONG_ADVANCED
613 default y
614
615config DEFAULT_TCP_CONG
616 string
617 default "bic" if DEFAULT_BIC
618 default "cubic" if DEFAULT_CUBIC
619 default "htcp" if DEFAULT_HTCP
620 default "hybla" if DEFAULT_HYBLA
621 default "vegas" if DEFAULT_VEGAS
622 default "westwood" if DEFAULT_WESTWOOD
623 default "veno" if DEFAULT_VENO
624 default "reno" if DEFAULT_RENO
625 default "cubic"
626
627config TCP_MD5SIG
628 bool "TCP: MD5 Signature Option support (RFC2385)"
629 select CRYPTO
630 select CRYPTO_MD5
631 ---help---
632 RFC2385 specifies a method of giving MD5 protection to TCP sessions.
633 Its main (only?) use is to protect BGP sessions between core routers
634 on the Internet.
635
636 If unsure, say N.