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-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 17config IP_ADVANCED_ROUTER 18 bool "IP: advanced router" 19 ---help--- 20 If you intend to run your Linux box mostly as a router, i.e. as a 21 computer that forwards and redistributes network packets, say Y; you 22 will then be presented with several options that allow more precise 23 control about the routing process. 24 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 29 Note that your box can only act as a router if you enable IP 30 forwarding in your kernel; you can do that by saying Y to "/proc 31 file system support" and "Sysctl support" below and executing the 32 line 33 34 echo "1" > /proc/sys/net/ipv4/ip_forward 35 36 at boot time after the /proc file system has been mounted. 37 38 If you turn on IP forwarding, you will also get the rp_filter, which 39 automatically rejects incoming packets if the routing table entry 40 for their source address doesn't match the network interface they're 41 arriving on. This has security advantages because it prevents the 42 so-called IP spoofing, however it can pose problems if you use 43 asymmetric routing (packets from you to a host take a different path 44 than packets from that host to you) or if you operate a non-routing 45 host which has several IP addresses on different interfaces. To turn 46 rp_filter off use: 47 48 echo 0 > /proc/sys/net/ipv4/conf/<device>/rp_filter 49 or 50 echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter 51 52 If unsure, say N here. 53 54choice 55 prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)" 56 depends on IP_ADVANCED_ROUTER 57 default ASK_IP_FIB_HASH 58 59config ASK_IP_FIB_HASH 60 bool "FIB_HASH" 61 ---help--- 62 Current FIB is very proven and good enough for most users. 63 64config IP_FIB_TRIE 65 bool "FIB_TRIE" 66 ---help--- 67 Use new experimental LC-trie as FIB lookup algoritm. 68 This improves lookup performance if you have a large 69 number of routes. 70 71 LC-trie is a longest matching prefix lookup algorithm which 72 performs better than FIB_HASH for large routing tables. 73 But, it consumes more memory and is more complex. 74 75 LC-trie is described in: 76 77 IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson 78 IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999 79 An experimental study of compression methods for dynamic tries 80 Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002. 81 http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/ 82 83endchoice 84 85config IP_FIB_HASH 86 def_bool ASK_IP_FIB_HASH || !IP_ADVANCED_ROUTER 87 88config IP_MULTIPLE_TABLES 89 bool "IP: policy routing" 90 depends on IP_ADVANCED_ROUTER 91 ---help--- 92 Normally, a router decides what to do with a received packet based 93 solely on the packet's final destination address. If you say Y here, 94 the Linux router will also be able to take the packet's source 95 address into account. Furthermore, the TOS (Type-Of-Service) field 96 of the packet can be used for routing decisions as well. 97 98 If you are interested in this, please see the preliminary 99 documentation at <http://www.compendium.com.ar/policy-routing.txt> 100 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>. 101 You will need supporting software from 102 <ftp://ftp.tux.org/pub/net/ip-routing/>. 103 104 If unsure, say N. 105 106config IP_ROUTE_FWMARK 107 bool "IP: use netfilter MARK value as routing key" 108 depends on IP_MULTIPLE_TABLES && NETFILTER 109 help 110 If you say Y here, you will be able to specify different routes for 111 packets with different mark values (see iptables(8), MARK target). 112 113config IP_ROUTE_MULTIPATH 114 bool "IP: equal cost multipath" 115 depends on IP_ADVANCED_ROUTER 116 help 117 Normally, the routing tables specify a single action to be taken in 118 a deterministic manner for a given packet. If you say Y here 119 however, it becomes possible to attach several actions to a packet 120 pattern, in effect specifying several alternative paths to travel 121 for those packets. The router considers all these paths to be of 122 equal "cost" and chooses one of them in a non-deterministic fashion 123 if a matching packet arrives. 124 125config IP_ROUTE_MULTIPATH_CACHED 126 bool "IP: equal cost multipath with caching support (EXPERIMENTAL)" 127 depends on IP_ROUTE_MULTIPATH 128 help 129 Normally, equal cost multipath routing is not supported by the 130 routing cache. If you say Y here, alternative routes are cached 131 and on cache lookup a route is chosen in a configurable fashion. 132 133 If unsure, say N. 134 135config IP_ROUTE_MULTIPATH_RR 136 tristate "MULTIPATH: round robin algorithm" 137 depends on IP_ROUTE_MULTIPATH_CACHED 138 help 139 Mulitpath routes are chosen according to Round Robin 140 141config IP_ROUTE_MULTIPATH_RANDOM 142 tristate "MULTIPATH: random algorithm" 143 depends on IP_ROUTE_MULTIPATH_CACHED 144 help 145 Multipath routes are chosen in a random fashion. Actually, 146 there is no weight for a route. The advantage of this policy 147 is that it is implemented stateless and therefore introduces only 148 a very small delay. 149 150config IP_ROUTE_MULTIPATH_WRANDOM 151 tristate "MULTIPATH: weighted random algorithm" 152 depends on IP_ROUTE_MULTIPATH_CACHED 153 help 154 Multipath routes are chosen in a weighted random fashion. 155 The per route weights are the weights visible via ip route 2. As the 156 corresponding state management introduces some overhead routing delay 157 is increased. 158 159config IP_ROUTE_MULTIPATH_DRR 160 tristate "MULTIPATH: interface round robin algorithm" 161 depends on IP_ROUTE_MULTIPATH_CACHED 162 help 163 Connections are distributed in a round robin fashion over the 164 available interfaces. This policy makes sense if the connections 165 should be primarily distributed on interfaces and not on routes. 166 167config IP_ROUTE_VERBOSE 168 bool "IP: verbose route monitoring" 169 depends on IP_ADVANCED_ROUTER 170 help 171 If you say Y here, which is recommended, then the kernel will print 172 verbose messages regarding the routing, for example warnings about 173 received packets which look strange and could be evidence of an 174 attack or a misconfigured system somewhere. The information is 175 handled by the klogd daemon which is responsible for kernel messages 176 ("man klogd"). 177 178config IP_PNP 179 bool "IP: kernel level autoconfiguration" 180 help 181 This enables automatic configuration of IP addresses of devices and 182 of the routing table during kernel boot, based on either information 183 supplied on the kernel command line or by BOOTP or RARP protocols. 184 You need to say Y only for diskless machines requiring network 185 access to boot (in which case you want to say Y to "Root file system 186 on NFS" as well), because all other machines configure the network 187 in their startup scripts. 188 189config IP_PNP_DHCP 190 bool "IP: DHCP support" 191 depends on IP_PNP 192 ---help--- 193 If you want your Linux box to mount its whole root file system (the 194 one containing the directory /) from some other computer over the 195 net via NFS and you want the IP address of your computer to be 196 discovered automatically at boot time using the DHCP protocol (a 197 special protocol designed for doing this job), say Y here. In case 198 the boot ROM of your network card was designed for booting Linux and 199 does DHCP itself, providing all necessary information on the kernel 200 command line, you can say N here. 201 202 If unsure, say Y. Note that if you want to use DHCP, a DHCP server 203 must be operating on your network. Read 204 <file:Documentation/nfsroot.txt> for details. 205 206config IP_PNP_BOOTP 207 bool "IP: BOOTP support" 208 depends on IP_PNP 209 ---help--- 210 If you want your Linux box to mount its whole root file system (the 211 one containing the directory /) from some other computer over the 212 net via NFS and you want the IP address of your computer to be 213 discovered automatically at boot time using the BOOTP protocol (a 214 special protocol designed for doing this job), say Y here. In case 215 the boot ROM of your network card was designed for booting Linux and 216 does BOOTP itself, providing all necessary information on the kernel 217 command line, you can say N here. If unsure, say Y. Note that if you 218 want to use BOOTP, a BOOTP server must be operating on your network. 219 Read <file:Documentation/nfsroot.txt> for details. 220 221config IP_PNP_RARP 222 bool "IP: RARP support" 223 depends on IP_PNP 224 help 225 If you want your Linux box to mount its whole root file system (the 226 one containing the directory /) from some other computer over the 227 net via NFS and you want the IP address of your computer to be 228 discovered automatically at boot time using the RARP protocol (an 229 older protocol which is being obsoleted by BOOTP and DHCP), say Y 230 here. Note that if you want to use RARP, a RARP server must be 231 operating on your network. Read <file:Documentation/nfsroot.txt> for 232 details. 233 234# not yet ready.. 235# bool ' IP: ARP support' CONFIG_IP_PNP_ARP 236config NET_IPIP 237 tristate "IP: tunneling" 238 select INET_TUNNEL 239 ---help--- 240 Tunneling means encapsulating data of one protocol type within 241 another protocol and sending it over a channel that understands the 242 encapsulating protocol. This particular tunneling driver implements 243 encapsulation of IP within IP, which sounds kind of pointless, but 244 can be useful if you want to make your (or some other) machine 245 appear on a different network than it physically is, or to use 246 mobile-IP facilities (allowing laptops to seamlessly move between 247 networks without changing their IP addresses). 248 249 Saying Y to this option will produce two modules ( = code which can 250 be inserted in and removed from the running kernel whenever you 251 want). Most people won't need this and can say N. 252 253config NET_IPGRE 254 tristate "IP: GRE tunnels over IP" 255 help 256 Tunneling means encapsulating data of one protocol type within 257 another protocol and sending it over a channel that understands the 258 encapsulating protocol. This particular tunneling driver implements 259 GRE (Generic Routing Encapsulation) and at this time allows 260 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 261 This driver is useful if the other endpoint is a Cisco router: Cisco 262 likes GRE much better than the other Linux tunneling driver ("IP 263 tunneling" above). In addition, GRE allows multicast redistribution 264 through the tunnel. 265 266config NET_IPGRE_BROADCAST 267 bool "IP: broadcast GRE over IP" 268 depends on IP_MULTICAST && NET_IPGRE 269 help 270 One application of GRE/IP is to construct a broadcast WAN (Wide Area 271 Network), which looks like a normal Ethernet LAN (Local Area 272 Network), but can be distributed all over the Internet. If you want 273 to do that, say Y here and to "IP multicast routing" below. 274 275config IP_MROUTE 276 bool "IP: multicast routing" 277 depends on IP_MULTICAST 278 help 279 This is used if you want your machine to act as a router for IP 280 packets that have several destination addresses. It is needed on the 281 MBONE, a high bandwidth network on top of the Internet which carries 282 audio and video broadcasts. In order to do that, you would most 283 likely run the program mrouted. Information about the multicast 284 capabilities of the various network cards is contained in 285 <file:Documentation/networking/multicast.txt>. If you haven't heard 286 about it, you don't need it. 287 288config IP_PIMSM_V1 289 bool "IP: PIM-SM version 1 support" 290 depends on IP_MROUTE 291 help 292 Kernel side support for Sparse Mode PIM (Protocol Independent 293 Multicast) version 1. This multicast routing protocol is used widely 294 because Cisco supports it. You need special software to use it 295 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 296 information about PIM. 297 298 Say Y if you want to use PIM-SM v1. Note that you can say N here if 299 you just want to use Dense Mode PIM. 300 301config IP_PIMSM_V2 302 bool "IP: PIM-SM version 2 support" 303 depends on IP_MROUTE 304 help 305 Kernel side support for Sparse Mode PIM version 2. In order to use 306 this, you need an experimental routing daemon supporting it (pimd or 307 gated-5). This routing protocol is not used widely, so say N unless 308 you want to play with it. 309 310config ARPD 311 bool "IP: ARP daemon support (EXPERIMENTAL)" 312 depends on EXPERIMENTAL 313 ---help--- 314 Normally, the kernel maintains an internal cache which maps IP 315 addresses to hardware addresses on the local network, so that 316 Ethernet/Token Ring/ etc. frames are sent to the proper address on 317 the physical networking layer. For small networks having a few 318 hundred directly connected hosts or less, keeping this address 319 resolution (ARP) cache inside the kernel works well. However, 320 maintaining an internal ARP cache does not work well for very large 321 switched networks, and will use a lot of kernel memory if TCP/IP 322 connections are made to many machines on the network. 323 324 If you say Y here, the kernel's internal ARP cache will never grow 325 to more than 256 entries (the oldest entries are expired in a LIFO 326 manner) and communication will be attempted with the user space ARP 327 daemon arpd. Arpd then answers the address resolution request either 328 from its own cache or by asking the net. 329 330 This code is experimental and also obsolete. If you want to use it, 331 you need to find a version of the daemon arpd on the net somewhere, 332 and you should also say Y to "Kernel/User network link driver", 333 below. If unsure, say N. 334 335config SYN_COOKIES 336 bool "IP: TCP syncookie support (disabled per default)" 337 ---help--- 338 Normal TCP/IP networking is open to an attack known as "SYN 339 flooding". This denial-of-service attack prevents legitimate remote 340 users from being able to connect to your computer during an ongoing 341 attack and requires very little work from the attacker, who can 342 operate from anywhere on the Internet. 343 344 SYN cookies provide protection against this type of attack. If you 345 say Y here, the TCP/IP stack will use a cryptographic challenge 346 protocol known as "SYN cookies" to enable legitimate users to 347 continue to connect, even when your machine is under attack. There 348 is no need for the legitimate users to change their TCP/IP software; 349 SYN cookies work transparently to them. For technical information 350 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 351 352 If you are SYN flooded, the source address reported by the kernel is 353 likely to have been forged by the attacker; it is only reported as 354 an aid in tracing the packets to their actual source and should not 355 be taken as absolute truth. 356 357 SYN cookies may prevent correct error reporting on clients when the 358 server is really overloaded. If this happens frequently better turn 359 them off. 360 361 If you say Y here, note that SYN cookies aren't enabled by default; 362 you can enable them by saying Y to "/proc file system support" and 363 "Sysctl support" below and executing the command 364 365 echo 1 >/proc/sys/net/ipv4/tcp_syncookies 366 367 at boot time after the /proc file system has been mounted. 368 369 If unsure, say N. 370 371config INET_AH 372 tristate "IP: AH transformation" 373 select XFRM 374 select CRYPTO 375 select CRYPTO_HMAC 376 select CRYPTO_MD5 377 select CRYPTO_SHA1 378 ---help--- 379 Support for IPsec AH. 380 381 If unsure, say Y. 382 383config INET_ESP 384 tristate "IP: ESP transformation" 385 select XFRM 386 select CRYPTO 387 select CRYPTO_HMAC 388 select CRYPTO_MD5 389 select CRYPTO_SHA1 390 select CRYPTO_DES 391 ---help--- 392 Support for IPsec ESP. 393 394 If unsure, say Y. 395 396config INET_IPCOMP 397 tristate "IP: IPComp transformation" 398 select XFRM 399 select INET_XFRM_TUNNEL 400 select CRYPTO 401 select CRYPTO_DEFLATE 402 ---help--- 403 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 404 typically needed for IPsec. 405 406 If unsure, say Y. 407 408config INET_XFRM_TUNNEL 409 tristate 410 select INET_TUNNEL 411 default n 412 413config INET_TUNNEL 414 tristate 415 default n 416 417config INET_DIAG 418 tristate "INET: socket monitoring interface" 419 default y 420 ---help--- 421 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 422 native Linux tools such as ss. ss is included in iproute2, currently 423 downloadable at <http://developer.osdl.org/dev/iproute2>. 424 425 If unsure, say Y. 426 427config INET_TCP_DIAG 428 depends on INET_DIAG 429 def_tristate INET_DIAG 430 431config 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 (BIC-TCP with new Reno as a fallback). 439 440 If unsure, say N. 441 442# TCP Reno is builtin (required as fallback) 443menu "TCP congestion control" 444 depends on TCP_CONG_ADVANCED 445 446config TCP_CONG_BIC 447 tristate "Binary Increase Congestion (BIC) control" 448 default y 449 ---help--- 450 BIC-TCP is a sender-side only change that ensures a linear RTT 451 fairness under large windows while offering both scalability and 452 bounded TCP-friendliness. The protocol combines two schemes 453 called additive increase and binary search increase. When the 454 congestion window is large, additive increase with a large 455 increment ensures linear RTT fairness as well as good 456 scalability. Under small congestion windows, binary search 457 increase provides TCP friendliness. 458 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 459 460config TCP_CONG_CUBIC 461 tristate "CUBIC TCP" 462 default m 463 ---help--- 464 This is version 2.0 of BIC-TCP which uses a cubic growth function 465 among other techniques. 466 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 467 468config TCP_CONG_WESTWOOD 469 tristate "TCP Westwood+" 470 default m 471 ---help--- 472 TCP Westwood+ is a sender-side only modification of the TCP Reno 473 protocol stack that optimizes the performance of TCP congestion 474 control. It is based on end-to-end bandwidth estimation to set 475 congestion window and slow start threshold after a congestion 476 episode. Using this estimation, TCP Westwood+ adaptively sets a 477 slow start threshold and a congestion window which takes into 478 account the bandwidth used at the time congestion is experienced. 479 TCP Westwood+ significantly increases fairness wrt TCP Reno in 480 wired networks and throughput over wireless links. 481 482config TCP_CONG_HTCP 483 tristate "H-TCP" 484 default m 485 ---help--- 486 H-TCP is a send-side only modifications of the TCP Reno 487 protocol stack that optimizes the performance of TCP 488 congestion control for high speed network links. It uses a 489 modeswitch to change the alpha and beta parameters of TCP Reno 490 based on network conditions and in a way so as to be fair with 491 other Reno and H-TCP flows. 492 493config TCP_CONG_HSTCP 494 tristate "High Speed TCP" 495 depends on EXPERIMENTAL 496 default n 497 ---help--- 498 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 499 A modification to TCP's congestion control mechanism for use 500 with large congestion windows. A table indicates how much to 501 increase the congestion window by when an ACK is received. 502 For more detail see http://www.icir.org/floyd/hstcp.html 503 504config TCP_CONG_HYBLA 505 tristate "TCP-Hybla congestion control algorithm" 506 depends on EXPERIMENTAL 507 default n 508 ---help--- 509 TCP-Hybla is a sender-side only change that eliminates penalization of 510 long-RTT, large-bandwidth connections, like when satellite legs are 511 involved, expecially when sharing a common bottleneck with normal 512 terrestrial connections. 513 514config TCP_CONG_VEGAS 515 tristate "TCP Vegas" 516 depends on EXPERIMENTAL 517 default n 518 ---help--- 519 TCP Vegas is a sender-side only change to TCP that anticipates 520 the onset of congestion by estimating the bandwidth. TCP Vegas 521 adjusts the sending rate by modifying the congestion 522 window. TCP Vegas should provide less packet loss, but it is 523 not as aggressive as TCP Reno. 524 525config TCP_CONG_SCALABLE 526 tristate "Scalable TCP" 527 depends on EXPERIMENTAL 528 default n 529 ---help--- 530 Scalable TCP is a sender-side only change to TCP which uses a 531 MIMD congestion control algorithm which has some nice scaling 532 properties, though is known to have fairness issues. 533 See http://www-lce.eng.cam.ac.uk/~ctk21/scalable/ 534 535endmenu 536 537config TCP_CONG_BIC 538 tristate 539 depends on !TCP_CONG_ADVANCED 540 default y 541 542source "net/ipv4/ipvs/Kconfig" 543 544