Kconfig 21 KB

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  1. #
  2. # IP configuration
  3. #
  4. config IP_MULTICAST
  5. bool "IP: multicasting"
  6. depends on INET
  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. <http://www-itg.lbl.gov/mbone/>. Information about the multicast
  14. capabilities of the various network cards is contained in
  15. <file:Documentation/networking/multicast.txt>. For most people, it's
  16. safe to say N.
  17. config IP_ADVANCED_ROUTER
  18. bool "IP: advanced router"
  19. depends on INET
  20. ---help---
  21. If you intend to run your Linux box mostly as a router, i.e. as a
  22. computer that forwards and redistributes network packets, say Y; you
  23. will then be presented with several options that allow more precise
  24. control about the routing process.
  25. The answer to this question won't directly affect the kernel:
  26. answering N will just cause the configurator to skip all the
  27. questions about advanced routing.
  28. Note that your box can only act as a router if you enable IP
  29. forwarding in your kernel; you can do that by saying Y to "/proc
  30. file system support" and "Sysctl support" below and executing the
  31. line
  32. echo "1" > /proc/sys/net/ipv4/ip_forward
  33. at boot time after the /proc file system has been mounted.
  34. If you turn on IP forwarding, you will also get the rp_filter, which
  35. automatically rejects incoming packets if the routing table entry
  36. for their source address doesn't match the network interface they're
  37. arriving on. This has security advantages because it prevents the
  38. so-called IP spoofing, however it can pose problems if you use
  39. asymmetric routing (packets from you to a host take a different path
  40. than packets from that host to you) or if you operate a non-routing
  41. host which has several IP addresses on different interfaces. To turn
  42. rp_filter off use:
  43. echo 0 > /proc/sys/net/ipv4/conf/<device>/rp_filter
  44. or
  45. echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter
  46. If unsure, say N here.
  47. choice
  48. prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)"
  49. depends on IP_ADVANCED_ROUTER
  50. default IP_FIB_HASH
  51. config IP_FIB_HASH
  52. bool "FIB_HASH"
  53. ---help---
  54. Current FIB is very proven and good enough for most users.
  55. config IP_FIB_TRIE
  56. bool "FIB_TRIE"
  57. ---help---
  58. Use new experimental LC-trie as FIB lookup algoritm.
  59. This improves lookup performance if you have a large
  60. number of routes.
  61. LC-trie is a longest matching prefix lookup algorithm which
  62. performs better than FIB_HASH for large routing tables.
  63. But, it consumes more memory and is more complex.
  64. LC-trie is described in:
  65. IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
  66. IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
  67. An experimental study of compression methods for dynamic tries
  68. Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
  69. http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/
  70. endchoice
  71. # If the user does not enable advanced routing, he gets the safe
  72. # default of the fib-hash algorithm.
  73. config IP_FIB_HASH
  74. bool
  75. depends on !IP_ADVANCED_ROUTER
  76. default y
  77. config IP_MULTIPLE_TABLES
  78. bool "IP: policy routing"
  79. depends on IP_ADVANCED_ROUTER
  80. ---help---
  81. Normally, a router decides what to do with a received packet based
  82. solely on the packet's final destination address. If you say Y here,
  83. the Linux router will also be able to take the packet's source
  84. address into account. Furthermore, the TOS (Type-Of-Service) field
  85. of the packet can be used for routing decisions as well.
  86. If you are interested in this, please see the preliminary
  87. documentation at <http://www.compendium.com.ar/policy-routing.txt>
  88. and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>.
  89. You will need supporting software from
  90. <ftp://ftp.tux.org/pub/net/ip-routing/>.
  91. If unsure, say N.
  92. config IP_ROUTE_FWMARK
  93. bool "IP: use netfilter MARK value as routing key"
  94. depends on IP_MULTIPLE_TABLES && NETFILTER
  95. help
  96. If you say Y here, you will be able to specify different routes for
  97. packets with different mark values (see iptables(8), MARK target).
  98. config IP_ROUTE_MULTIPATH
  99. bool "IP: equal cost multipath"
  100. depends on IP_ADVANCED_ROUTER
  101. help
  102. Normally, the routing tables specify a single action to be taken in
  103. a deterministic manner for a given packet. If you say Y here
  104. however, it becomes possible to attach several actions to a packet
  105. pattern, in effect specifying several alternative paths to travel
  106. for those packets. The router considers all these paths to be of
  107. equal "cost" and chooses one of them in a non-deterministic fashion
  108. if a matching packet arrives.
  109. config IP_ROUTE_MULTIPATH_CACHED
  110. bool "IP: equal cost multipath with caching support (EXPERIMENTAL)"
  111. depends on: IP_ROUTE_MULTIPATH
  112. help
  113. Normally, equal cost multipath routing is not supported by the
  114. routing cache. If you say Y here, alternative routes are cached
  115. and on cache lookup a route is chosen in a configurable fashion.
  116. If unsure, say N.
  117. config IP_ROUTE_MULTIPATH_RR
  118. tristate "MULTIPATH: round robin algorithm"
  119. depends on IP_ROUTE_MULTIPATH_CACHED
  120. help
  121. Mulitpath routes are chosen according to Round Robin
  122. config IP_ROUTE_MULTIPATH_RANDOM
  123. tristate "MULTIPATH: random algorithm"
  124. depends on IP_ROUTE_MULTIPATH_CACHED
  125. help
  126. Multipath routes are chosen in a random fashion. Actually,
  127. there is no weight for a route. The advantage of this policy
  128. is that it is implemented stateless and therefore introduces only
  129. a very small delay.
  130. config IP_ROUTE_MULTIPATH_WRANDOM
  131. tristate "MULTIPATH: weighted random algorithm"
  132. depends on IP_ROUTE_MULTIPATH_CACHED
  133. help
  134. Multipath routes are chosen in a weighted random fashion.
  135. The per route weights are the weights visible via ip route 2. As the
  136. corresponding state management introduces some overhead routing delay
  137. is increased.
  138. config IP_ROUTE_MULTIPATH_DRR
  139. tristate "MULTIPATH: interface round robin algorithm"
  140. depends on IP_ROUTE_MULTIPATH_CACHED
  141. help
  142. Connections are distributed in a round robin fashion over the
  143. available interfaces. This policy makes sense if the connections
  144. should be primarily distributed on interfaces and not on routes.
  145. config IP_ROUTE_VERBOSE
  146. bool "IP: verbose route monitoring"
  147. depends on IP_ADVANCED_ROUTER
  148. help
  149. If you say Y here, which is recommended, then the kernel will print
  150. verbose messages regarding the routing, for example warnings about
  151. received packets which look strange and could be evidence of an
  152. attack or a misconfigured system somewhere. The information is
  153. handled by the klogd daemon which is responsible for kernel messages
  154. ("man klogd").
  155. config IP_PNP
  156. bool "IP: kernel level autoconfiguration"
  157. depends on INET
  158. help
  159. This enables automatic configuration of IP addresses of devices and
  160. of the routing table during kernel boot, based on either information
  161. supplied on the kernel command line or by BOOTP or RARP protocols.
  162. You need to say Y only for diskless machines requiring network
  163. access to boot (in which case you want to say Y to "Root file system
  164. on NFS" as well), because all other machines configure the network
  165. in their startup scripts.
  166. config IP_PNP_DHCP
  167. bool "IP: DHCP support"
  168. depends on IP_PNP
  169. ---help---
  170. If you want your Linux box to mount its whole root file system (the
  171. one containing the directory /) from some other computer over the
  172. net via NFS and you want the IP address of your computer to be
  173. discovered automatically at boot time using the DHCP protocol (a
  174. special protocol designed for doing this job), say Y here. In case
  175. the boot ROM of your network card was designed for booting Linux and
  176. does DHCP itself, providing all necessary information on the kernel
  177. command line, you can say N here.
  178. If unsure, say Y. Note that if you want to use DHCP, a DHCP server
  179. must be operating on your network. Read
  180. <file:Documentation/nfsroot.txt> for details.
  181. config IP_PNP_BOOTP
  182. bool "IP: BOOTP support"
  183. depends on IP_PNP
  184. ---help---
  185. If you want your Linux box to mount its whole root file system (the
  186. one containing the directory /) from some other computer over the
  187. net via NFS and you want the IP address of your computer to be
  188. discovered automatically at boot time using the BOOTP protocol (a
  189. special protocol designed for doing this job), say Y here. In case
  190. the boot ROM of your network card was designed for booting Linux and
  191. does BOOTP itself, providing all necessary information on the kernel
  192. command line, you can say N here. If unsure, say Y. Note that if you
  193. want to use BOOTP, a BOOTP server must be operating on your network.
  194. Read <file:Documentation/nfsroot.txt> for details.
  195. config IP_PNP_RARP
  196. bool "IP: RARP support"
  197. depends on IP_PNP
  198. help
  199. If you want your Linux box to mount its whole root file system (the
  200. one containing the directory /) from some other computer over the
  201. net via NFS and you want the IP address of your computer to be
  202. discovered automatically at boot time using the RARP protocol (an
  203. older protocol which is being obsoleted by BOOTP and DHCP), say Y
  204. here. Note that if you want to use RARP, a RARP server must be
  205. operating on your network. Read <file:Documentation/nfsroot.txt> for
  206. details.
  207. # not yet ready..
  208. # bool ' IP: ARP support' CONFIG_IP_PNP_ARP
  209. config NET_IPIP
  210. tristate "IP: tunneling"
  211. depends on INET
  212. select INET_TUNNEL
  213. ---help---
  214. Tunneling means encapsulating data of one protocol type within
  215. another protocol and sending it over a channel that understands the
  216. encapsulating protocol. This particular tunneling driver implements
  217. encapsulation of IP within IP, which sounds kind of pointless, but
  218. can be useful if you want to make your (or some other) machine
  219. appear on a different network than it physically is, or to use
  220. mobile-IP facilities (allowing laptops to seamlessly move between
  221. networks without changing their IP addresses).
  222. Saying Y to this option will produce two modules ( = code which can
  223. be inserted in and removed from the running kernel whenever you
  224. want). Most people won't need this and can say N.
  225. config NET_IPGRE
  226. tristate "IP: GRE tunnels over IP"
  227. depends on INET
  228. select XFRM
  229. help
  230. Tunneling means encapsulating data of one protocol type within
  231. another protocol and sending it over a channel that understands the
  232. encapsulating protocol. This particular tunneling driver implements
  233. GRE (Generic Routing Encapsulation) and at this time allows
  234. encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
  235. This driver is useful if the other endpoint is a Cisco router: Cisco
  236. likes GRE much better than the other Linux tunneling driver ("IP
  237. tunneling" above). In addition, GRE allows multicast redistribution
  238. through the tunnel.
  239. config NET_IPGRE_BROADCAST
  240. bool "IP: broadcast GRE over IP"
  241. depends on IP_MULTICAST && NET_IPGRE
  242. help
  243. One application of GRE/IP is to construct a broadcast WAN (Wide Area
  244. Network), which looks like a normal Ethernet LAN (Local Area
  245. Network), but can be distributed all over the Internet. If you want
  246. to do that, say Y here and to "IP multicast routing" below.
  247. config IP_MROUTE
  248. bool "IP: multicast routing"
  249. depends on IP_MULTICAST
  250. help
  251. This is used if you want your machine to act as a router for IP
  252. packets that have several destination addresses. It is needed on the
  253. MBONE, a high bandwidth network on top of the Internet which carries
  254. audio and video broadcasts. In order to do that, you would most
  255. likely run the program mrouted. Information about the multicast
  256. capabilities of the various network cards is contained in
  257. <file:Documentation/networking/multicast.txt>. If you haven't heard
  258. about it, you don't need it.
  259. config IP_PIMSM_V1
  260. bool "IP: PIM-SM version 1 support"
  261. depends on IP_MROUTE
  262. help
  263. Kernel side support for Sparse Mode PIM (Protocol Independent
  264. Multicast) version 1. This multicast routing protocol is used widely
  265. because Cisco supports it. You need special software to use it
  266. (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
  267. information about PIM.
  268. Say Y if you want to use PIM-SM v1. Note that you can say N here if
  269. you just want to use Dense Mode PIM.
  270. config IP_PIMSM_V2
  271. bool "IP: PIM-SM version 2 support"
  272. depends on IP_MROUTE
  273. help
  274. Kernel side support for Sparse Mode PIM version 2. In order to use
  275. this, you need an experimental routing daemon supporting it (pimd or
  276. gated-5). This routing protocol is not used widely, so say N unless
  277. you want to play with it.
  278. config ARPD
  279. bool "IP: ARP daemon support (EXPERIMENTAL)"
  280. depends on INET && EXPERIMENTAL
  281. ---help---
  282. Normally, the kernel maintains an internal cache which maps IP
  283. addresses to hardware addresses on the local network, so that
  284. Ethernet/Token Ring/ etc. frames are sent to the proper address on
  285. the physical networking layer. For small networks having a few
  286. hundred directly connected hosts or less, keeping this address
  287. resolution (ARP) cache inside the kernel works well. However,
  288. maintaining an internal ARP cache does not work well for very large
  289. switched networks, and will use a lot of kernel memory if TCP/IP
  290. connections are made to many machines on the network.
  291. If you say Y here, the kernel's internal ARP cache will never grow
  292. to more than 256 entries (the oldest entries are expired in a LIFO
  293. manner) and communication will be attempted with the user space ARP
  294. daemon arpd. Arpd then answers the address resolution request either
  295. from its own cache or by asking the net.
  296. This code is experimental and also obsolete. If you want to use it,
  297. you need to find a version of the daemon arpd on the net somewhere,
  298. and you should also say Y to "Kernel/User network link driver",
  299. below. If unsure, say N.
  300. config SYN_COOKIES
  301. bool "IP: TCP syncookie support (disabled per default)"
  302. depends on INET
  303. ---help---
  304. Normal TCP/IP networking is open to an attack known as "SYN
  305. flooding". This denial-of-service attack prevents legitimate remote
  306. users from being able to connect to your computer during an ongoing
  307. attack and requires very little work from the attacker, who can
  308. operate from anywhere on the Internet.
  309. SYN cookies provide protection against this type of attack. If you
  310. say Y here, the TCP/IP stack will use a cryptographic challenge
  311. protocol known as "SYN cookies" to enable legitimate users to
  312. continue to connect, even when your machine is under attack. There
  313. is no need for the legitimate users to change their TCP/IP software;
  314. SYN cookies work transparently to them. For technical information
  315. about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
  316. If you are SYN flooded, the source address reported by the kernel is
  317. likely to have been forged by the attacker; it is only reported as
  318. an aid in tracing the packets to their actual source and should not
  319. be taken as absolute truth.
  320. SYN cookies may prevent correct error reporting on clients when the
  321. server is really overloaded. If this happens frequently better turn
  322. them off.
  323. If you say Y here, note that SYN cookies aren't enabled by default;
  324. you can enable them by saying Y to "/proc file system support" and
  325. "Sysctl support" below and executing the command
  326. echo 1 >/proc/sys/net/ipv4/tcp_syncookies
  327. at boot time after the /proc file system has been mounted.
  328. If unsure, say N.
  329. config INET_AH
  330. tristate "IP: AH transformation"
  331. depends on INET
  332. select XFRM
  333. select CRYPTO
  334. select CRYPTO_HMAC
  335. select CRYPTO_MD5
  336. select CRYPTO_SHA1
  337. ---help---
  338. Support for IPsec AH.
  339. If unsure, say Y.
  340. config INET_ESP
  341. tristate "IP: ESP transformation"
  342. depends on INET
  343. select XFRM
  344. select CRYPTO
  345. select CRYPTO_HMAC
  346. select CRYPTO_MD5
  347. select CRYPTO_SHA1
  348. select CRYPTO_DES
  349. ---help---
  350. Support for IPsec ESP.
  351. If unsure, say Y.
  352. config INET_IPCOMP
  353. tristate "IP: IPComp transformation"
  354. depends on INET
  355. select XFRM
  356. select INET_TUNNEL
  357. select CRYPTO
  358. select CRYPTO_DEFLATE
  359. ---help---
  360. Support for IP Payload Compression Protocol (IPComp) (RFC3173),
  361. typically needed for IPsec.
  362. If unsure, say Y.
  363. config INET_TUNNEL
  364. tristate "IP: tunnel transformation"
  365. depends on INET
  366. select XFRM
  367. ---help---
  368. Support for generic IP tunnel transformation, which is required by
  369. the IP tunneling module as well as tunnel mode IPComp.
  370. If unsure, say Y.
  371. config IP_TCPDIAG
  372. tristate "IP: TCP socket monitoring interface"
  373. depends on INET
  374. default y
  375. ---help---
  376. Support for TCP socket monitoring interface used by native Linux
  377. tools such as ss. ss is included in iproute2, currently downloadable
  378. at <http://developer.osdl.org/dev/iproute2>. If you want IPv6 support
  379. and have selected IPv6 as a module, you need to build this as a
  380. module too.
  381. If unsure, say Y.
  382. config IP_TCPDIAG_IPV6
  383. def_bool (IP_TCPDIAG=y && IPV6=y) || (IP_TCPDIAG=m && IPV6)
  384. config TCP_CONG_ADVANCED
  385. bool "TCP: advanced congestion control"
  386. depends on INET
  387. ---help---
  388. Support for selection of various TCP congestion control
  389. modules.
  390. Nearly all users can safely say no here, and a safe default
  391. selection will be made (BIC-TCP with new Reno as a fallback).
  392. If unsure, say N.
  393. # TCP Reno is builtin (required as fallback)
  394. menu "TCP congestion control"
  395. depends on TCP_CONG_ADVANCED
  396. config TCP_CONG_BIC
  397. tristate "Binary Increase Congestion (BIC) control"
  398. depends on INET
  399. default y
  400. ---help---
  401. BIC-TCP is a sender-side only change that ensures a linear RTT
  402. fairness under large windows while offering both scalability and
  403. bounded TCP-friendliness. The protocol combines two schemes
  404. called additive increase and binary search increase. When the
  405. congestion window is large, additive increase with a large
  406. increment ensures linear RTT fairness as well as good
  407. scalability. Under small congestion windows, binary search
  408. increase provides TCP friendliness.
  409. See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
  410. config TCP_CONG_WESTWOOD
  411. tristate "TCP Westwood+"
  412. depends on INET
  413. default m
  414. ---help---
  415. TCP Westwood+ is a sender-side only modification of the TCP Reno
  416. protocol stack that optimizes the performance of TCP congestion
  417. control. It is based on end-to-end bandwidth estimation to set
  418. congestion window and slow start threshold after a congestion
  419. episode. Using this estimation, TCP Westwood+ adaptively sets a
  420. slow start threshold and a congestion window which takes into
  421. account the bandwidth used at the time congestion is experienced.
  422. TCP Westwood+ significantly increases fairness wrt TCP Reno in
  423. wired networks and throughput over wireless links.
  424. config TCP_CONG_HTCP
  425. tristate "H-TCP"
  426. depends on INET
  427. default m
  428. ---help---
  429. H-TCP is a send-side only modifications of the TCP Reno
  430. protocol stack that optimizes the performance of TCP
  431. congestion control for high speed network links. It uses a
  432. modeswitch to change the alpha and beta parameters of TCP Reno
  433. based on network conditions and in a way so as to be fair with
  434. other Reno and H-TCP flows.
  435. config TCP_CONG_HSTCP
  436. tristate "High Speed TCP"
  437. depends on INET && EXPERIMENTAL
  438. default n
  439. ---help---
  440. Sally Floyd's High Speed TCP (RFC 3649) congestion control.
  441. A modification to TCP's congestion control mechanism for use
  442. with large congestion windows. A table indicates how much to
  443. increase the congestion window by when an ACK is received.
  444. For more detail see http://www.icir.org/floyd/hstcp.html
  445. config TCP_CONG_HYBLA
  446. tristate "TCP-Hybla congestion control algorithm"
  447. depends on INET && EXPERIMENTAL
  448. default n
  449. ---help---
  450. TCP-Hybla is a sender-side only change that eliminates penalization of
  451. long-RTT, large-bandwidth connections, like when satellite legs are
  452. involved, expecially when sharing a common bottleneck with normal
  453. terrestrial connections.
  454. config TCP_CONG_VEGAS
  455. tristate "TCP Vegas"
  456. depends on INET && EXPERIMENTAL
  457. default n
  458. ---help---
  459. TCP Vegas is a sender-side only change to TCP that anticipates
  460. the onset of congestion by estimating the bandwidth. TCP Vegas
  461. adjusts the sending rate by modifying the congestion
  462. window. TCP Vegas should provide less packet loss, but it is
  463. not as aggressive as TCP Reno.
  464. config TCP_CONG_SCALABLE
  465. tristate "Scalable TCP"
  466. depends on INET && EXPERIMENTAL
  467. default n
  468. ---help---
  469. Scalable TCP is a sender-side only change to TCP which uses a
  470. MIMD congestion control algorithm which has some nice scaling
  471. properties, though is known to have fairness issues.
  472. See http://www-lce.eng.cam.ac.uk/~ctk21/scalable/
  473. endmenu
  474. config TCP_CONG_BIC
  475. tristate
  476. depends on !TCP_CONG_ADVANCED
  477. default y
  478. source "net/ipv4/ipvs/Kconfig"