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/>. 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 should consider 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 on use: 47 48 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter 49 and 50 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter 51 52 Note that some distributions enable it in startup scripts. 53 For details about rp_filter strict and loose mode read 54 <file:Documentation/networking/ip-sysctl.txt>. 55 56 If unsure, say N here. 57 58choice 59 prompt "Choose IP: FIB lookup algorithm (choose FIB_HASH if unsure)" 60 depends on IP_ADVANCED_ROUTER 61 default ASK_IP_FIB_HASH 62 63config ASK_IP_FIB_HASH 64 bool "FIB_HASH" 65 ---help--- 66 Current FIB is very proven and good enough for most users. 67 68config IP_FIB_TRIE 69 bool "FIB_TRIE" 70 ---help--- 71 Use new experimental LC-trie as FIB lookup algorithm. 72 This improves lookup performance if you have a large 73 number of routes. 74 75 LC-trie is a longest matching prefix lookup algorithm which 76 performs better than FIB_HASH for large routing tables. 77 But, it consumes more memory and is more complex. 78 79 LC-trie is described in: 80 81 IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson 82 IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, 83 June 1999 84 85 An experimental study of compression methods for dynamic tries 86 Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002. 87 http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/ 88 89endchoice 90 91config IP_FIB_HASH 92 def_bool ASK_IP_FIB_HASH || !IP_ADVANCED_ROUTER 93 94config IP_FIB_TRIE_STATS 95 bool "FIB TRIE statistics" 96 depends on IP_FIB_TRIE 97 ---help--- 98 Keep track of statistics on structure of FIB TRIE table. 99 Useful for testing and measuring TRIE performance. 100 101config IP_MULTIPLE_TABLES 102 bool "IP: policy routing" 103 depends on IP_ADVANCED_ROUTER 104 select FIB_RULES 105 ---help--- 106 Normally, a router decides what to do with a received packet based 107 solely on the packet's final destination address. If you say Y here, 108 the Linux router will also be able to take the packet's source 109 address into account. Furthermore, the TOS (Type-Of-Service) field 110 of the packet can be used for routing decisions as well. 111 112 If you are interested in this, please see the preliminary 113 documentation at <http://www.compendium.com.ar/policy-routing.txt> 114 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>. 115 You will need supporting software from 116 <ftp://ftp.tux.org/pub/net/ip-routing/>. 117 118 If unsure, say N. 119 120config IP_ROUTE_MULTIPATH 121 bool "IP: equal cost multipath" 122 depends on IP_ADVANCED_ROUTER 123 help 124 Normally, the routing tables specify a single action to be taken in 125 a deterministic manner for a given packet. If you say Y here 126 however, it becomes possible to attach several actions to a packet 127 pattern, in effect specifying several alternative paths to travel 128 for those packets. The router considers all these paths to be of 129 equal "cost" and chooses one of them in a non-deterministic fashion 130 if a matching packet arrives. 131 132config IP_ROUTE_VERBOSE 133 bool "IP: verbose route monitoring" 134 depends on IP_ADVANCED_ROUTER 135 help 136 If you say Y here, which is recommended, then the kernel will print 137 verbose messages regarding the routing, for example warnings about 138 received packets which look strange and could be evidence of an 139 attack or a misconfigured system somewhere. The information is 140 handled by the klogd daemon which is responsible for kernel messages 141 ("man klogd"). 142 143config IP_PNP 144 bool "IP: kernel level autoconfiguration" 145 help 146 This enables automatic configuration of IP addresses of devices and 147 of the routing table during kernel boot, based on either information 148 supplied on the kernel command line or by BOOTP or RARP protocols. 149 You need to say Y only for diskless machines requiring network 150 access to boot (in which case you want to say Y to "Root file system 151 on NFS" as well), because all other machines configure the network 152 in their startup scripts. 153 154config IP_PNP_DHCP 155 bool "IP: DHCP support" 156 depends on IP_PNP 157 ---help--- 158 If you want your Linux box to mount its whole root file system (the 159 one containing the directory /) from some other computer over the 160 net via NFS and you want the IP address of your computer to be 161 discovered automatically at boot time using the DHCP protocol (a 162 special protocol designed for doing this job), say Y here. In case 163 the boot ROM of your network card was designed for booting Linux and 164 does DHCP itself, providing all necessary information on the kernel 165 command line, you can say N here. 166 167 If unsure, say Y. Note that if you want to use DHCP, a DHCP server 168 must be operating on your network. Read 169 <file:Documentation/filesystems/nfsroot.txt> for details. 170 171config IP_PNP_BOOTP 172 bool "IP: BOOTP support" 173 depends on IP_PNP 174 ---help--- 175 If you want your Linux box to mount its whole root file system (the 176 one containing the directory /) from some other computer over the 177 net via NFS and you want the IP address of your computer to be 178 discovered automatically at boot time using the BOOTP protocol (a 179 special protocol designed for doing this job), say Y here. In case 180 the boot ROM of your network card was designed for booting Linux and 181 does BOOTP itself, providing all necessary information on the kernel 182 command line, you can say N here. If unsure, say Y. Note that if you 183 want to use BOOTP, a BOOTP server must be operating on your network. 184 Read <file:Documentation/filesystems/nfsroot.txt> for details. 185 186config IP_PNP_RARP 187 bool "IP: RARP support" 188 depends on IP_PNP 189 help 190 If you want your Linux box to mount its whole root file system (the 191 one containing the directory /) from some other computer over the 192 net via NFS and you want the IP address of your computer to be 193 discovered automatically at boot time using the RARP protocol (an 194 older protocol which is being obsoleted by BOOTP and DHCP), say Y 195 here. Note that if you want to use RARP, a RARP server must be 196 operating on your network. Read 197 <file:Documentation/filesystems/nfsroot.txt> for details. 198 199# not yet ready.. 200# bool ' IP: ARP support' CONFIG_IP_PNP_ARP 201config NET_IPIP 202 tristate "IP: tunneling" 203 select INET_TUNNEL 204 ---help--- 205 Tunneling means encapsulating data of one protocol type within 206 another protocol and sending it over a channel that understands the 207 encapsulating protocol. This particular tunneling driver implements 208 encapsulation of IP within IP, which sounds kind of pointless, but 209 can be useful if you want to make your (or some other) machine 210 appear on a different network than it physically is, or to use 211 mobile-IP facilities (allowing laptops to seamlessly move between 212 networks without changing their IP addresses). 213 214 Saying Y to this option will produce two modules ( = code which can 215 be inserted in and removed from the running kernel whenever you 216 want). Most people won't need this and can say N. 217 218config NET_IPGRE 219 tristate "IP: GRE tunnels over IP" 220 help 221 Tunneling means encapsulating data of one protocol type within 222 another protocol and sending it over a channel that understands the 223 encapsulating protocol. This particular tunneling driver implements 224 GRE (Generic Routing Encapsulation) and at this time allows 225 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 226 This driver is useful if the other endpoint is a Cisco router: Cisco 227 likes GRE much better than the other Linux tunneling driver ("IP 228 tunneling" above). In addition, GRE allows multicast redistribution 229 through the tunnel. 230 231config NET_IPGRE_BROADCAST 232 bool "IP: broadcast GRE over IP" 233 depends on IP_MULTICAST && NET_IPGRE 234 help 235 One application of GRE/IP is to construct a broadcast WAN (Wide Area 236 Network), which looks like a normal Ethernet LAN (Local Area 237 Network), but can be distributed all over the Internet. If you want 238 to do that, say Y here and to "IP multicast routing" below. 239 240config IP_MROUTE 241 bool "IP: multicast routing" 242 depends on IP_MULTICAST 243 help 244 This is used if you want your machine to act as a router for IP 245 packets that have several destination addresses. It is needed on the 246 MBONE, a high bandwidth network on top of the Internet which carries 247 audio and video broadcasts. In order to do that, you would most 248 likely run the program mrouted. Information about the multicast 249 capabilities of the various network cards is contained in 250 <file:Documentation/networking/multicast.txt>. If you haven't heard 251 about it, you don't need it. 252 253config IP_PIMSM_V1 254 bool "IP: PIM-SM version 1 support" 255 depends on IP_MROUTE 256 help 257 Kernel side support for Sparse Mode PIM (Protocol Independent 258 Multicast) version 1. This multicast routing protocol is used widely 259 because Cisco supports it. You need special software to use it 260 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 261 information about PIM. 262 263 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 266config IP_PIMSM_V2 267 bool "IP: PIM-SM version 2 support" 268 depends on IP_MROUTE 269 help 270 Kernel side support for Sparse Mode PIM version 2. In order to use 271 this, you need an experimental routing daemon supporting it (pimd or 272 gated-5). This routing protocol is not used widely, so say N unless 273 you want to play with it. 274 275config ARPD 276 bool "IP: ARP daemon support" 277 ---help--- 278 The kernel maintains an internal cache which maps IP addresses to 279 hardware addresses on the local network, so that Ethernet/Token Ring/ 280 etc. frames are sent to the proper address on the physical networking 281 layer. Normally, kernel uses the ARP protocol to resolve these 282 mappings. 283 284 Saying Y here adds support to have an user space daemon to do this 285 resolution instead. This is useful for implementing an alternate 286 address resolution protocol (e.g. NHRP on mGRE tunnels) and also for 287 testing purposes. 288 289 If unsure, say N. 290 291config SYN_COOKIES 292 bool "IP: TCP syncookie support (disabled per default)" 293 ---help--- 294 Normal TCP/IP networking is open to an attack known as "SYN 295 flooding". This denial-of-service attack prevents legitimate remote 296 users from being able to connect to your computer during an ongoing 297 attack and requires very little work from the attacker, who can 298 operate from anywhere on the Internet. 299 300 SYN cookies provide protection against this type of attack. If you 301 say Y here, the TCP/IP stack will use a cryptographic challenge 302 protocol known as "SYN cookies" to enable legitimate users to 303 continue to connect, even when your machine is under attack. There 304 is no need for the legitimate users to change their TCP/IP software; 305 SYN cookies work transparently to them. For technical information 306 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 307 308 If you are SYN flooded, the source address reported by the kernel is 309 likely to have been forged by the attacker; it is only reported as 310 an aid in tracing the packets to their actual source and should not 311 be taken as absolute truth. 312 313 SYN cookies may prevent correct error reporting on clients when the 314 server is really overloaded. If this happens frequently better turn 315 them off. 316 317 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 320 321 echo 1 >/proc/sys/net/ipv4/tcp_syncookies 322 323 at boot time after the /proc file system has been mounted. 324 325 If unsure, say N. 326 327config INET_AH 328 tristate "IP: AH transformation" 329 select XFRM 330 select CRYPTO 331 select CRYPTO_HMAC 332 select CRYPTO_MD5 333 select CRYPTO_SHA1 334 ---help--- 335 Support for IPsec AH. 336 337 If unsure, say Y. 338 339config INET_ESP 340 tristate "IP: ESP transformation" 341 select XFRM 342 select CRYPTO 343 select CRYPTO_AUTHENC 344 select CRYPTO_HMAC 345 select CRYPTO_MD5 346 select CRYPTO_CBC 347 select CRYPTO_SHA1 348 select CRYPTO_DES 349 ---help--- 350 Support for IPsec ESP. 351 352 If unsure, say Y. 353 354config INET_IPCOMP 355 tristate "IP: IPComp transformation" 356 select INET_XFRM_TUNNEL 357 select XFRM_IPCOMP 358 ---help--- 359 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 360 typically needed for IPsec. 361 362 If unsure, say Y. 363 364config INET_XFRM_TUNNEL 365 tristate 366 select INET_TUNNEL 367 default n 368 369config INET_TUNNEL 370 tristate 371 default n 372 373config INET_XFRM_MODE_TRANSPORT 374 tristate "IP: IPsec transport mode" 375 default y 376 select XFRM 377 ---help--- 378 Support for IPsec transport mode. 379 380 If unsure, say Y. 381 382config INET_XFRM_MODE_TUNNEL 383 tristate "IP: IPsec tunnel mode" 384 default y 385 select XFRM 386 ---help--- 387 Support for IPsec tunnel mode. 388 389 If unsure, say Y. 390 391config INET_XFRM_MODE_BEET 392 tristate "IP: IPsec BEET mode" 393 default y 394 select XFRM 395 ---help--- 396 Support for IPsec BEET mode. 397 398 If unsure, say Y. 399 400config INET_LRO 401 bool "Large Receive Offload (ipv4/tcp)" 402 default y 403 ---help--- 404 Support for Large Receive Offload (ipv4/tcp). 405 406 If unsure, say Y. 407 408config INET_DIAG 409 tristate "INET: socket monitoring interface" 410 default y 411 ---help--- 412 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 413 native Linux tools such as ss. ss is included in iproute2, currently 414 downloadable at <http://linux-net.osdl.org/index.php/Iproute2>. 415 416 If unsure, say Y. 417 418config INET_TCP_DIAG 419 depends on INET_DIAG 420 def_tristate INET_DIAG 421 422menuconfig TCP_CONG_ADVANCED 423 bool "TCP: advanced congestion control" 424 ---help--- 425 Support for selection of various TCP congestion control 426 modules. 427 428 Nearly all users can safely say no here, and a safe default 429 selection will be made (CUBIC with new Reno as a fallback). 430 431 If unsure, say N. 432 433if TCP_CONG_ADVANCED 434 435config TCP_CONG_BIC 436 tristate "Binary Increase Congestion (BIC) control" 437 default m 438 ---help--- 439 BIC-TCP is a sender-side only change that ensures a linear RTT 440 fairness under large windows while offering both scalability and 441 bounded TCP-friendliness. The protocol combines two schemes 442 called additive increase and binary search increase. When the 443 congestion window is large, additive increase with a large 444 increment ensures linear RTT fairness as well as good 445 scalability. Under small congestion windows, binary search 446 increase provides TCP friendliness. 447 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 448 449config TCP_CONG_CUBIC 450 tristate "CUBIC TCP" 451 default y 452 ---help--- 453 This is version 2.0 of BIC-TCP which uses a cubic growth function 454 among other techniques. 455 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 456 457config TCP_CONG_WESTWOOD 458 tristate "TCP Westwood+" 459 default m 460 ---help--- 461 TCP Westwood+ is a sender-side only modification of the TCP Reno 462 protocol stack that optimizes the performance of TCP congestion 463 control. It is based on end-to-end bandwidth estimation to set 464 congestion window and slow start threshold after a congestion 465 episode. Using this estimation, TCP Westwood+ adaptively sets a 466 slow start threshold and a congestion window which takes into 467 account the bandwidth used at the time congestion is experienced. 468 TCP Westwood+ significantly increases fairness wrt TCP Reno in 469 wired networks and throughput over wireless links. 470 471config TCP_CONG_HTCP 472 tristate "H-TCP" 473 default m 474 ---help--- 475 H-TCP is a send-side only modifications of the TCP Reno 476 protocol stack that optimizes the performance of TCP 477 congestion control for high speed network links. It uses a 478 modeswitch to change the alpha and beta parameters of TCP Reno 479 based on network conditions and in a way so as to be fair with 480 other Reno and H-TCP flows. 481 482config TCP_CONG_HSTCP 483 tristate "High Speed TCP" 484 depends on EXPERIMENTAL 485 default n 486 ---help--- 487 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 488 A modification to TCP's congestion control mechanism for use 489 with large congestion windows. A table indicates how much to 490 increase the congestion window by when an ACK is received. 491 For more detail see http://www.icir.org/floyd/hstcp.html 492 493config TCP_CONG_HYBLA 494 tristate "TCP-Hybla congestion control algorithm" 495 depends on EXPERIMENTAL 496 default n 497 ---help--- 498 TCP-Hybla is a sender-side only change that eliminates penalization of 499 long-RTT, large-bandwidth connections, like when satellite legs are 500 involved, especially when sharing a common bottleneck with normal 501 terrestrial connections. 502 503config TCP_CONG_VEGAS 504 tristate "TCP Vegas" 505 depends on EXPERIMENTAL 506 default n 507 ---help--- 508 TCP Vegas is a sender-side only change to TCP that anticipates 509 the onset of congestion by estimating the bandwidth. TCP Vegas 510 adjusts the sending rate by modifying the congestion 511 window. TCP Vegas should provide less packet loss, but it is 512 not as aggressive as TCP Reno. 513 514config TCP_CONG_SCALABLE 515 tristate "Scalable TCP" 516 depends on EXPERIMENTAL 517 default n 518 ---help--- 519 Scalable TCP is a sender-side only change to TCP which uses a 520 MIMD congestion control algorithm which has some nice scaling 521 properties, though is known to have fairness issues. 522 See http://www.deneholme.net/tom/scalable/ 523 524config TCP_CONG_LP 525 tristate "TCP Low Priority" 526 depends on EXPERIMENTAL 527 default n 528 ---help--- 529 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 530 to utilize only the excess network bandwidth as compared to the 531 ``fair share`` of bandwidth as targeted by TCP. 532 See http://www-ece.rice.edu/networks/TCP-LP/ 533 534config TCP_CONG_VENO 535 tristate "TCP Veno" 536 depends on EXPERIMENTAL 537 default n 538 ---help--- 539 TCP Veno is a sender-side only enhancement of TCP to obtain better 540 throughput over wireless networks. TCP Veno makes use of state 541 distinguishing to circumvent the difficult judgment of the packet loss 542 type. TCP Veno cuts down less congestion window in response to random 543 loss packets. 544 See http://www.ntu.edu.sg/home5/ZHOU0022/papers/CPFu03a.pdf 545 546config TCP_CONG_YEAH 547 tristate "YeAH TCP" 548 depends on EXPERIMENTAL 549 select TCP_CONG_VEGAS 550 default n 551 ---help--- 552 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 553 algorithm, which uses a mixed loss/delay approach to compute the 554 congestion window. It's design goals target high efficiency, 555 internal, RTT and Reno fairness, resilience to link loss while 556 keeping network elements load as low as possible. 557 558 For further details look here: 559 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 560 561config TCP_CONG_ILLINOIS 562 tristate "TCP Illinois" 563 depends on EXPERIMENTAL 564 default n 565 ---help--- 566 TCP-Illinois is a sender-side modification of TCP Reno for 567 high speed long delay links. It uses round-trip-time to 568 adjust the alpha and beta parameters to achieve a higher average 569 throughput and maintain fairness. 570 571 For further details see: 572 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 573 574choice 575 prompt "Default TCP congestion control" 576 default DEFAULT_CUBIC 577 help 578 Select the TCP congestion control that will be used by default 579 for all connections. 580 581 config DEFAULT_BIC 582 bool "Bic" if TCP_CONG_BIC=y 583 584 config DEFAULT_CUBIC 585 bool "Cubic" if TCP_CONG_CUBIC=y 586 587 config DEFAULT_HTCP 588 bool "Htcp" if TCP_CONG_HTCP=y 589 590 config DEFAULT_VEGAS 591 bool "Vegas" if TCP_CONG_VEGAS=y 592 593 config DEFAULT_WESTWOOD 594 bool "Westwood" if TCP_CONG_WESTWOOD=y 595 596 config DEFAULT_RENO 597 bool "Reno" 598 599endchoice 600 601endif 602 603config TCP_CONG_CUBIC 604 tristate 605 depends on !TCP_CONG_ADVANCED 606 default y 607 608config DEFAULT_TCP_CONG 609 string 610 default "bic" if DEFAULT_BIC 611 default "cubic" if DEFAULT_CUBIC 612 default "htcp" if DEFAULT_HTCP 613 default "vegas" if DEFAULT_VEGAS 614 default "westwood" if DEFAULT_WESTWOOD 615 default "reno" if DEFAULT_RENO 616 default "cubic" 617 618config TCP_MD5SIG 619 bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)" 620 depends on EXPERIMENTAL 621 select CRYPTO 622 select CRYPTO_MD5 623 ---help--- 624 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 625 Its main (only?) use is to protect BGP sessions between core routers 626 on the Internet. 627 628 If unsure, say N. 629 630