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/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_DEMUX 219 tristate "IP: GRE demultiplexer" 220 help 221 This is helper module to demultiplex GRE packets on GRE version field criteria. 222 Required by ip_gre and pptp modules. 223 224config NET_IPGRE 225 tristate "IP: GRE tunnels over IP" 226 depends on NET_IPGRE_DEMUX 227 help 228 Tunneling means encapsulating data of one protocol type within 229 another protocol and sending it over a channel that understands the 230 encapsulating protocol. This particular tunneling driver implements 231 GRE (Generic Routing Encapsulation) and at this time allows 232 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 233 This driver is useful if the other endpoint is a Cisco router: Cisco 234 likes GRE much better than the other Linux tunneling driver ("IP 235 tunneling" above). In addition, GRE allows multicast redistribution 236 through the tunnel. 237 238config NET_IPGRE_BROADCAST 239 bool "IP: broadcast GRE over IP" 240 depends on IP_MULTICAST && NET_IPGRE 241 help 242 One application of GRE/IP is to construct a broadcast WAN (Wide Area 243 Network), which looks like a normal Ethernet LAN (Local Area 244 Network), but can be distributed all over the Internet. If you want 245 to do that, say Y here and to "IP multicast routing" below. 246 247config 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 260config IP_MROUTE_MULTIPLE_TABLES 261 bool "IP: multicast policy routing" 262 depends on IP_MROUTE && IP_ADVANCED_ROUTER 263 select FIB_RULES 264 help 265 Normally, a multicast router runs a userspace daemon and decides 266 what to do with a multicast packet based on the source and 267 destination addresses. If you say Y here, the multicast router 268 will also be able to take interfaces and packet marks into 269 account and run multiple instances of userspace daemons 270 simultaneously, each one handling a single table. 271 272 If unsure, say N. 273 274config IP_PIMSM_V1 275 bool "IP: PIM-SM version 1 support" 276 depends on IP_MROUTE 277 help 278 Kernel side support for Sparse Mode PIM (Protocol Independent 279 Multicast) version 1. This multicast routing protocol is used widely 280 because Cisco supports it. You need special software to use it 281 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 282 information about PIM. 283 284 Say Y if you want to use PIM-SM v1. Note that you can say N here if 285 you just want to use Dense Mode PIM. 286 287config IP_PIMSM_V2 288 bool "IP: PIM-SM version 2 support" 289 depends on IP_MROUTE 290 help 291 Kernel side support for Sparse Mode PIM version 2. In order to use 292 this, you need an experimental routing daemon supporting it (pimd or 293 gated-5). This routing protocol is not used widely, so say N unless 294 you want to play with it. 295 296config ARPD 297 bool "IP: ARP daemon support" 298 ---help--- 299 The kernel maintains an internal cache which maps IP addresses to 300 hardware addresses on the local network, so that Ethernet/Token Ring/ 301 etc. frames are sent to the proper address on the physical networking 302 layer. Normally, kernel uses the ARP protocol to resolve these 303 mappings. 304 305 Saying Y here adds support to have an user space daemon to do this 306 resolution instead. This is useful for implementing an alternate 307 address resolution protocol (e.g. NHRP on mGRE tunnels) and also for 308 testing purposes. 309 310 If unsure, say N. 311 312config SYN_COOKIES 313 bool "IP: TCP syncookie support" 314 ---help--- 315 Normal TCP/IP networking is open to an attack known as "SYN 316 flooding". This denial-of-service attack prevents legitimate remote 317 users from being able to connect to your computer during an ongoing 318 attack and requires very little work from the attacker, who can 319 operate from anywhere on the Internet. 320 321 SYN cookies provide protection against this type of attack. If you 322 say Y here, the TCP/IP stack will use a cryptographic challenge 323 protocol known as "SYN cookies" to enable legitimate users to 324 continue to connect, even when your machine is under attack. There 325 is no need for the legitimate users to change their TCP/IP software; 326 SYN cookies work transparently to them. For technical information 327 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 328 329 If you are SYN flooded, the source address reported by the kernel is 330 likely to have been forged by the attacker; it is only reported as 331 an aid in tracing the packets to their actual source and should not 332 be taken as absolute truth. 333 334 SYN cookies may prevent correct error reporting on clients when the 335 server is really overloaded. If this happens frequently better turn 336 them off. 337 338 If you say Y here, you can disable SYN cookies at run time by 339 saying Y to "/proc file system support" and 340 "Sysctl support" below and executing the command 341 342 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 343 344 after the /proc file system has been mounted. 345 346 If unsure, say N. 347 348config INET_AH 349 tristate "IP: AH transformation" 350 select XFRM 351 select CRYPTO 352 select CRYPTO_HMAC 353 select CRYPTO_MD5 354 select CRYPTO_SHA1 355 ---help--- 356 Support for IPsec AH. 357 358 If unsure, say Y. 359 360config INET_ESP 361 tristate "IP: ESP transformation" 362 select XFRM 363 select CRYPTO 364 select CRYPTO_AUTHENC 365 select CRYPTO_HMAC 366 select CRYPTO_MD5 367 select CRYPTO_CBC 368 select CRYPTO_SHA1 369 select CRYPTO_DES 370 ---help--- 371 Support for IPsec ESP. 372 373 If unsure, say Y. 374 375config INET_IPCOMP 376 tristate "IP: IPComp transformation" 377 select INET_XFRM_TUNNEL 378 select XFRM_IPCOMP 379 ---help--- 380 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 381 typically needed for IPsec. 382 383 If unsure, say Y. 384 385config INET_XFRM_TUNNEL 386 tristate 387 select INET_TUNNEL 388 default n 389 390config INET_TUNNEL 391 tristate 392 default n 393 394config INET_XFRM_MODE_TRANSPORT 395 tristate "IP: IPsec transport mode" 396 default y 397 select XFRM 398 ---help--- 399 Support for IPsec transport mode. 400 401 If unsure, say Y. 402 403config INET_XFRM_MODE_TUNNEL 404 tristate "IP: IPsec tunnel mode" 405 default y 406 select XFRM 407 ---help--- 408 Support for IPsec tunnel mode. 409 410 If unsure, say Y. 411 412config INET_XFRM_MODE_BEET 413 tristate "IP: IPsec BEET mode" 414 default y 415 select XFRM 416 ---help--- 417 Support for IPsec BEET mode. 418 419 If unsure, say Y. 420 421config INET_LRO 422 bool "Large Receive Offload (ipv4/tcp)" 423 default y 424 ---help--- 425 Support for Large Receive Offload (ipv4/tcp). 426 427 If unsure, say Y. 428 429config INET_DIAG 430 tristate "INET: socket monitoring interface" 431 default y 432 ---help--- 433 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 434 native Linux tools such as ss. ss is included in iproute2, currently 435 downloadable at <http://linux-net.osdl.org/index.php/Iproute2>. 436 437 If unsure, say Y. 438 439config INET_TCP_DIAG 440 depends on INET_DIAG 441 def_tristate INET_DIAG 442 443menuconfig TCP_CONG_ADVANCED 444 bool "TCP: advanced congestion control" 445 ---help--- 446 Support for selection of various TCP congestion control 447 modules. 448 449 Nearly all users can safely say no here, and a safe default 450 selection will be made (CUBIC with new Reno as a fallback). 451 452 If unsure, say N. 453 454if TCP_CONG_ADVANCED 455 456config TCP_CONG_BIC 457 tristate "Binary Increase Congestion (BIC) control" 458 default m 459 ---help--- 460 BIC-TCP is a sender-side only change that ensures a linear RTT 461 fairness under large windows while offering both scalability and 462 bounded TCP-friendliness. The protocol combines two schemes 463 called additive increase and binary search increase. When the 464 congestion window is large, additive increase with a large 465 increment ensures linear RTT fairness as well as good 466 scalability. Under small congestion windows, binary search 467 increase provides TCP friendliness. 468 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 469 470config TCP_CONG_CUBIC 471 tristate "CUBIC TCP" 472 default y 473 ---help--- 474 This is version 2.0 of BIC-TCP which uses a cubic growth function 475 among other techniques. 476 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 477 478config TCP_CONG_WESTWOOD 479 tristate "TCP Westwood+" 480 default m 481 ---help--- 482 TCP Westwood+ is a sender-side only modification of the TCP Reno 483 protocol stack that optimizes the performance of TCP congestion 484 control. It is based on end-to-end bandwidth estimation to set 485 congestion window and slow start threshold after a congestion 486 episode. Using this estimation, TCP Westwood+ adaptively sets a 487 slow start threshold and a congestion window which takes into 488 account the bandwidth used at the time congestion is experienced. 489 TCP Westwood+ significantly increases fairness wrt TCP Reno in 490 wired networks and throughput over wireless links. 491 492config TCP_CONG_HTCP 493 tristate "H-TCP" 494 default m 495 ---help--- 496 H-TCP is a send-side only modifications of the TCP Reno 497 protocol stack that optimizes the performance of TCP 498 congestion control for high speed network links. It uses a 499 modeswitch to change the alpha and beta parameters of TCP Reno 500 based on network conditions and in a way so as to be fair with 501 other Reno and H-TCP flows. 502 503config TCP_CONG_HSTCP 504 tristate "High Speed TCP" 505 depends on EXPERIMENTAL 506 default n 507 ---help--- 508 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 509 A modification to TCP's congestion control mechanism for use 510 with large congestion windows. A table indicates how much to 511 increase the congestion window by when an ACK is received. 512 For more detail see http://www.icir.org/floyd/hstcp.html 513 514config TCP_CONG_HYBLA 515 tristate "TCP-Hybla congestion control algorithm" 516 depends on EXPERIMENTAL 517 default n 518 ---help--- 519 TCP-Hybla is a sender-side only change that eliminates penalization of 520 long-RTT, large-bandwidth connections, like when satellite legs are 521 involved, especially when sharing a common bottleneck with normal 522 terrestrial connections. 523 524config TCP_CONG_VEGAS 525 tristate "TCP Vegas" 526 depends on EXPERIMENTAL 527 default n 528 ---help--- 529 TCP Vegas is a sender-side only change to TCP that anticipates 530 the onset of congestion by estimating the bandwidth. TCP Vegas 531 adjusts the sending rate by modifying the congestion 532 window. TCP Vegas should provide less packet loss, but it is 533 not as aggressive as TCP Reno. 534 535config TCP_CONG_SCALABLE 536 tristate "Scalable TCP" 537 depends on EXPERIMENTAL 538 default n 539 ---help--- 540 Scalable TCP is a sender-side only change to TCP which uses a 541 MIMD congestion control algorithm which has some nice scaling 542 properties, though is known to have fairness issues. 543 See http://www.deneholme.net/tom/scalable/ 544 545config TCP_CONG_LP 546 tristate "TCP Low Priority" 547 depends on EXPERIMENTAL 548 default n 549 ---help--- 550 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 551 to utilize only the excess network bandwidth as compared to the 552 ``fair share`` of bandwidth as targeted by TCP. 553 See http://www-ece.rice.edu/networks/TCP-LP/ 554 555config TCP_CONG_VENO 556 tristate "TCP Veno" 557 depends on EXPERIMENTAL 558 default n 559 ---help--- 560 TCP Veno is a sender-side only enhancement of TCP to obtain better 561 throughput over wireless networks. TCP Veno makes use of state 562 distinguishing to circumvent the difficult judgment of the packet loss 563 type. TCP Veno cuts down less congestion window in response to random 564 loss packets. 565 See http://www.ntu.edu.sg/home5/ZHOU0022/papers/CPFu03a.pdf 566 567config TCP_CONG_YEAH 568 tristate "YeAH TCP" 569 depends on EXPERIMENTAL 570 select TCP_CONG_VEGAS 571 default n 572 ---help--- 573 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 574 algorithm, which uses a mixed loss/delay approach to compute the 575 congestion window. It's design goals target high efficiency, 576 internal, RTT and Reno fairness, resilience to link loss while 577 keeping network elements load as low as possible. 578 579 For further details look here: 580 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 581 582config TCP_CONG_ILLINOIS 583 tristate "TCP Illinois" 584 depends on EXPERIMENTAL 585 default n 586 ---help--- 587 TCP-Illinois is a sender-side modification of TCP Reno for 588 high speed long delay links. It uses round-trip-time to 589 adjust the alpha and beta parameters to achieve a higher average 590 throughput and maintain fairness. 591 592 For further details see: 593 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 594 595choice 596 prompt "Default TCP congestion control" 597 default DEFAULT_CUBIC 598 help 599 Select the TCP congestion control that will be used by default 600 for all connections. 601 602 config DEFAULT_BIC 603 bool "Bic" if TCP_CONG_BIC=y 604 605 config DEFAULT_CUBIC 606 bool "Cubic" if TCP_CONG_CUBIC=y 607 608 config DEFAULT_HTCP 609 bool "Htcp" if TCP_CONG_HTCP=y 610 611 config DEFAULT_HYBLA 612 bool "Hybla" if TCP_CONG_HYBLA=y 613 614 config DEFAULT_VEGAS 615 bool "Vegas" if TCP_CONG_VEGAS=y 616 617 config DEFAULT_VENO 618 bool "Veno" if TCP_CONG_VENO=y 619 620 config DEFAULT_WESTWOOD 621 bool "Westwood" if TCP_CONG_WESTWOOD=y 622 623 config DEFAULT_RENO 624 bool "Reno" 625 626endchoice 627 628endif 629 630config TCP_CONG_CUBIC 631 tristate 632 depends on !TCP_CONG_ADVANCED 633 default y 634 635config DEFAULT_TCP_CONG 636 string 637 default "bic" if DEFAULT_BIC 638 default "cubic" if DEFAULT_CUBIC 639 default "htcp" if DEFAULT_HTCP 640 default "hybla" if DEFAULT_HYBLA 641 default "vegas" if DEFAULT_VEGAS 642 default "westwood" if DEFAULT_WESTWOOD 643 default "veno" if DEFAULT_VENO 644 default "reno" if DEFAULT_RENO 645 default "cubic" 646 647config TCP_MD5SIG 648 bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)" 649 depends on EXPERIMENTAL 650 select CRYPTO 651 select CRYPTO_MD5 652 ---help--- 653 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 654 Its main (only?) use is to protect BGP sessions between core routers 655 on the Internet. 656 657 If unsure, say N. 658 659