Kconfig 20 KB

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