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 or 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/nfs/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/nfs/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/nfs/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 depends on IPV6 || IPV6=n 221 help 222 Tunneling means encapsulating data of one protocol type within 223 another protocol and sending it over a channel that understands the 224 encapsulating protocol. This particular tunneling driver implements 225 GRE (Generic Routing Encapsulation) and at this time allows 226 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 227 This driver is useful if the other endpoint is a Cisco router: Cisco 228 likes GRE much better than the other Linux tunneling driver ("IP 229 tunneling" above). In addition, GRE allows multicast redistribution 230 through the tunnel. 231 232config NET_IPGRE_BROADCAST 233 bool "IP: broadcast GRE over IP" 234 depends on IP_MULTICAST && NET_IPGRE 235 help 236 One application of GRE/IP is to construct a broadcast WAN (Wide Area 237 Network), which looks like a normal Ethernet LAN (Local Area 238 Network), but can be distributed all over the Internet. If you want 239 to do that, say Y here and to "IP multicast routing" below. 240 241config IP_MROUTE 242 bool "IP: multicast routing" 243 depends on IP_MULTICAST 244 help 245 This is used if you want your machine to act as a router for IP 246 packets that have several destination addresses. It is needed on the 247 MBONE, a high bandwidth network on top of the Internet which carries 248 audio and video broadcasts. In order to do that, you would most 249 likely run the program mrouted. Information about the multicast 250 capabilities of the various network cards is contained in 251 <file:Documentation/networking/multicast.txt>. If you haven't heard 252 about it, you don't need it. 253 254config IP_MROUTE_MULTIPLE_TABLES 255 bool "IP: multicast policy routing" 256 depends on IP_MROUTE && IP_ADVANCED_ROUTER 257 select FIB_RULES 258 help 259 Normally, a multicast router runs a userspace daemon and decides 260 what to do with a multicast packet based on the source and 261 destination addresses. If you say Y here, the multicast router 262 will also be able to take interfaces and packet marks into 263 account and run multiple instances of userspace daemons 264 simultaneously, each one handling a single table. 265 266 If unsure, say N. 267 268config IP_PIMSM_V1 269 bool "IP: PIM-SM version 1 support" 270 depends on IP_MROUTE 271 help 272 Kernel side support for Sparse Mode PIM (Protocol Independent 273 Multicast) version 1. This multicast routing protocol is used widely 274 because Cisco supports it. You need special software to use it 275 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 276 information about PIM. 277 278 Say Y if you want to use PIM-SM v1. Note that you can say N here if 279 you just want to use Dense Mode PIM. 280 281config IP_PIMSM_V2 282 bool "IP: PIM-SM version 2 support" 283 depends on IP_MROUTE 284 help 285 Kernel side support for Sparse Mode PIM version 2. In order to use 286 this, you need an experimental routing daemon supporting it (pimd or 287 gated-5). This routing protocol is not used widely, so say N unless 288 you want to play with it. 289 290config ARPD 291 bool "IP: ARP daemon support" 292 ---help--- 293 The kernel maintains an internal cache which maps IP addresses to 294 hardware addresses on the local network, so that Ethernet/Token Ring/ 295 etc. frames are sent to the proper address on the physical networking 296 layer. Normally, kernel uses the ARP protocol to resolve these 297 mappings. 298 299 Saying Y here adds support to have an user space daemon to do this 300 resolution instead. This is useful for implementing an alternate 301 address resolution protocol (e.g. NHRP on mGRE tunnels) and also for 302 testing purposes. 303 304 If unsure, say N. 305 306config SYN_COOKIES 307 bool "IP: TCP syncookie support" 308 ---help--- 309 Normal TCP/IP networking is open to an attack known as "SYN 310 flooding". This denial-of-service attack prevents legitimate remote 311 users from being able to connect to your computer during an ongoing 312 attack and requires very little work from the attacker, who can 313 operate from anywhere on the Internet. 314 315 SYN cookies provide protection against this type of attack. If you 316 say Y here, the TCP/IP stack will use a cryptographic challenge 317 protocol known as "SYN cookies" to enable legitimate users to 318 continue to connect, even when your machine is under attack. There 319 is no need for the legitimate users to change their TCP/IP software; 320 SYN cookies work transparently to them. For technical information 321 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 322 323 If you are SYN flooded, the source address reported by the kernel is 324 likely to have been forged by the attacker; it is only reported as 325 an aid in tracing the packets to their actual source and should not 326 be taken as absolute truth. 327 328 SYN cookies may prevent correct error reporting on clients when the 329 server is really overloaded. If this happens frequently better turn 330 them off. 331 332 If you say Y here, you can disable SYN cookies at run time by 333 saying Y to "/proc file system support" and 334 "Sysctl support" below and executing the command 335 336 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 337 338 after the /proc file system has been mounted. 339 340 If unsure, say N. 341 342config INET_AH 343 tristate "IP: AH transformation" 344 select XFRM 345 select CRYPTO 346 select CRYPTO_HMAC 347 select CRYPTO_MD5 348 select CRYPTO_SHA1 349 ---help--- 350 Support for IPsec AH. 351 352 If unsure, say Y. 353 354config INET_ESP 355 tristate "IP: ESP transformation" 356 select XFRM 357 select CRYPTO 358 select CRYPTO_AUTHENC 359 select CRYPTO_HMAC 360 select CRYPTO_MD5 361 select CRYPTO_CBC 362 select CRYPTO_SHA1 363 select CRYPTO_DES 364 ---help--- 365 Support for IPsec ESP. 366 367 If unsure, say Y. 368 369config INET_IPCOMP 370 tristate "IP: IPComp transformation" 371 select INET_XFRM_TUNNEL 372 select XFRM_IPCOMP 373 ---help--- 374 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 375 typically needed for IPsec. 376 377 If unsure, say Y. 378 379config INET_XFRM_TUNNEL 380 tristate 381 select INET_TUNNEL 382 default n 383 384config INET_TUNNEL 385 tristate 386 default n 387 388config INET_XFRM_MODE_TRANSPORT 389 tristate "IP: IPsec transport mode" 390 default y 391 select XFRM 392 ---help--- 393 Support for IPsec transport mode. 394 395 If unsure, say Y. 396 397config INET_XFRM_MODE_TUNNEL 398 tristate "IP: IPsec tunnel mode" 399 default y 400 select XFRM 401 ---help--- 402 Support for IPsec tunnel mode. 403 404 If unsure, say Y. 405 406config INET_XFRM_MODE_BEET 407 tristate "IP: IPsec BEET mode" 408 default y 409 select XFRM 410 ---help--- 411 Support for IPsec BEET mode. 412 413 If unsure, say Y. 414 415config INET_LRO 416 tristate "Large Receive Offload (ipv4/tcp)" 417 default y 418 ---help--- 419 Support for Large Receive Offload (ipv4/tcp). 420 421 If unsure, say Y. 422 423config INET_DIAG 424 tristate "INET: socket monitoring interface" 425 default y 426 ---help--- 427 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 428 native Linux tools such as ss. ss is included in iproute2, currently 429 downloadable at <http://linux-net.osdl.org/index.php/Iproute2>. 430 431 If unsure, say Y. 432 433config INET_TCP_DIAG 434 depends on INET_DIAG 435 def_tristate INET_DIAG 436 437menuconfig TCP_CONG_ADVANCED 438 bool "TCP: advanced congestion control" 439 ---help--- 440 Support for selection of various TCP congestion control 441 modules. 442 443 Nearly all users can safely say no here, and a safe default 444 selection will be made (CUBIC with new Reno as a fallback). 445 446 If unsure, say N. 447 448if TCP_CONG_ADVANCED 449 450config TCP_CONG_BIC 451 tristate "Binary Increase Congestion (BIC) control" 452 default m 453 ---help--- 454 BIC-TCP is a sender-side only change that ensures a linear RTT 455 fairness under large windows while offering both scalability and 456 bounded TCP-friendliness. The protocol combines two schemes 457 called additive increase and binary search increase. When the 458 congestion window is large, additive increase with a large 459 increment ensures linear RTT fairness as well as good 460 scalability. Under small congestion windows, binary search 461 increase provides TCP friendliness. 462 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 463 464config TCP_CONG_CUBIC 465 tristate "CUBIC TCP" 466 default y 467 ---help--- 468 This is version 2.0 of BIC-TCP which uses a cubic growth function 469 among other techniques. 470 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 471 472config TCP_CONG_WESTWOOD 473 tristate "TCP Westwood+" 474 default m 475 ---help--- 476 TCP Westwood+ is a sender-side only modification of the TCP Reno 477 protocol stack that optimizes the performance of TCP congestion 478 control. It is based on end-to-end bandwidth estimation to set 479 congestion window and slow start threshold after a congestion 480 episode. Using this estimation, TCP Westwood+ adaptively sets a 481 slow start threshold and a congestion window which takes into 482 account the bandwidth used at the time congestion is experienced. 483 TCP Westwood+ significantly increases fairness wrt TCP Reno in 484 wired networks and throughput over wireless links. 485 486config TCP_CONG_HTCP 487 tristate "H-TCP" 488 default m 489 ---help--- 490 H-TCP is a send-side only modifications of the TCP Reno 491 protocol stack that optimizes the performance of TCP 492 congestion control for high speed network links. It uses a 493 modeswitch to change the alpha and beta parameters of TCP Reno 494 based on network conditions and in a way so as to be fair with 495 other Reno and H-TCP flows. 496 497config TCP_CONG_HSTCP 498 tristate "High Speed TCP" 499 depends on EXPERIMENTAL 500 default n 501 ---help--- 502 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 503 A modification to TCP's congestion control mechanism for use 504 with large congestion windows. A table indicates how much to 505 increase the congestion window by when an ACK is received. 506 For more detail see http://www.icir.org/floyd/hstcp.html 507 508config TCP_CONG_HYBLA 509 tristate "TCP-Hybla congestion control algorithm" 510 depends on EXPERIMENTAL 511 default n 512 ---help--- 513 TCP-Hybla is a sender-side only change that eliminates penalization of 514 long-RTT, large-bandwidth connections, like when satellite legs are 515 involved, especially when sharing a common bottleneck with normal 516 terrestrial connections. 517 518config TCP_CONG_VEGAS 519 tristate "TCP Vegas" 520 depends on EXPERIMENTAL 521 default n 522 ---help--- 523 TCP Vegas is a sender-side only change to TCP that anticipates 524 the onset of congestion by estimating the bandwidth. TCP Vegas 525 adjusts the sending rate by modifying the congestion 526 window. TCP Vegas should provide less packet loss, but it is 527 not as aggressive as TCP Reno. 528 529config TCP_CONG_SCALABLE 530 tristate "Scalable TCP" 531 depends on EXPERIMENTAL 532 default n 533 ---help--- 534 Scalable TCP is a sender-side only change to TCP which uses a 535 MIMD congestion control algorithm which has some nice scaling 536 properties, though is known to have fairness issues. 537 See http://www.deneholme.net/tom/scalable/ 538 539config TCP_CONG_LP 540 tristate "TCP Low Priority" 541 depends on EXPERIMENTAL 542 default n 543 ---help--- 544 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 545 to utilize only the excess network bandwidth as compared to the 546 ``fair share`` of bandwidth as targeted by TCP. 547 See http://www-ece.rice.edu/networks/TCP-LP/ 548 549config TCP_CONG_VENO 550 tristate "TCP Veno" 551 depends on EXPERIMENTAL 552 default n 553 ---help--- 554 TCP Veno is a sender-side only enhancement of TCP to obtain better 555 throughput over wireless networks. TCP Veno makes use of state 556 distinguishing to circumvent the difficult judgment of the packet loss 557 type. TCP Veno cuts down less congestion window in response to random 558 loss packets. 559 See http://www.ntu.edu.sg/home5/ZHOU0022/papers/CPFu03a.pdf 560 561config TCP_CONG_YEAH 562 tristate "YeAH TCP" 563 depends on EXPERIMENTAL 564 select TCP_CONG_VEGAS 565 default n 566 ---help--- 567 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 568 algorithm, which uses a mixed loss/delay approach to compute the 569 congestion window. It's design goals target high efficiency, 570 internal, RTT and Reno fairness, resilience to link loss while 571 keeping network elements load as low as possible. 572 573 For further details look here: 574 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 575 576config TCP_CONG_ILLINOIS 577 tristate "TCP Illinois" 578 depends on EXPERIMENTAL 579 default n 580 ---help--- 581 TCP-Illinois is a sender-side modification of TCP Reno for 582 high speed long delay links. It uses round-trip-time to 583 adjust the alpha and beta parameters to achieve a higher average 584 throughput and maintain fairness. 585 586 For further details see: 587 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 588 589choice 590 prompt "Default TCP congestion control" 591 default DEFAULT_CUBIC 592 help 593 Select the TCP congestion control that will be used by default 594 for all connections. 595 596 config DEFAULT_BIC 597 bool "Bic" if TCP_CONG_BIC=y 598 599 config DEFAULT_CUBIC 600 bool "Cubic" if TCP_CONG_CUBIC=y 601 602 config DEFAULT_HTCP 603 bool "Htcp" if TCP_CONG_HTCP=y 604 605 config DEFAULT_HYBLA 606 bool "Hybla" if TCP_CONG_HYBLA=y 607 608 config DEFAULT_VEGAS 609 bool "Vegas" if TCP_CONG_VEGAS=y 610 611 config DEFAULT_VENO 612 bool "Veno" if TCP_CONG_VENO=y 613 614 config DEFAULT_WESTWOOD 615 bool "Westwood" if TCP_CONG_WESTWOOD=y 616 617 config DEFAULT_RENO 618 bool "Reno" 619 620endchoice 621 622endif 623 624config TCP_CONG_CUBIC 625 tristate 626 depends on !TCP_CONG_ADVANCED 627 default y 628 629config DEFAULT_TCP_CONG 630 string 631 default "bic" if DEFAULT_BIC 632 default "cubic" if DEFAULT_CUBIC 633 default "htcp" if DEFAULT_HTCP 634 default "hybla" if DEFAULT_HYBLA 635 default "vegas" if DEFAULT_VEGAS 636 default "westwood" if DEFAULT_WESTWOOD 637 default "veno" if DEFAULT_VENO 638 default "reno" if DEFAULT_RENO 639 default "cubic" 640 641config TCP_MD5SIG 642 bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)" 643 depends on EXPERIMENTAL 644 select CRYPTO 645 select CRYPTO_MD5 646 ---help--- 647 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 648 Its main (only?) use is to protect BGP sessions between core routers 649 on the Internet. 650 651 If unsure, say N. 652 653