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 58config IP_FIB_TRIE_STATS 59 bool "FIB TRIE statistics" 60 depends on IP_ADVANCED_ROUTER 61 ---help--- 62 Keep track of statistics on structure of FIB TRIE table. 63 Useful for testing and measuring TRIE performance. 64 65config IP_MULTIPLE_TABLES 66 bool "IP: policy routing" 67 depends on IP_ADVANCED_ROUTER 68 select FIB_RULES 69 ---help--- 70 Normally, a router decides what to do with a received packet based 71 solely on the packet's final destination address. If you say Y here, 72 the Linux router will also be able to take the packet's source 73 address into account. Furthermore, the TOS (Type-Of-Service) field 74 of the packet can be used for routing decisions as well. 75 76 If you are interested in this, please see the preliminary 77 documentation at <http://www.compendium.com.ar/policy-routing.txt> 78 and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>. 79 You will need supporting software from 80 <ftp://ftp.tux.org/pub/net/ip-routing/>. 81 82 If unsure, say N. 83 84config IP_ROUTE_MULTIPATH 85 bool "IP: equal cost multipath" 86 depends on IP_ADVANCED_ROUTER 87 help 88 Normally, the routing tables specify a single action to be taken in 89 a deterministic manner for a given packet. If you say Y here 90 however, it becomes possible to attach several actions to a packet 91 pattern, in effect specifying several alternative paths to travel 92 for those packets. The router considers all these paths to be of 93 equal "cost" and chooses one of them in a non-deterministic fashion 94 if a matching packet arrives. 95 96config IP_ROUTE_VERBOSE 97 bool "IP: verbose route monitoring" 98 depends on IP_ADVANCED_ROUTER 99 help 100 If you say Y here, which is recommended, then the kernel will print 101 verbose messages regarding the routing, for example warnings about 102 received packets which look strange and could be evidence of an 103 attack or a misconfigured system somewhere. The information is 104 handled by the klogd daemon which is responsible for kernel messages 105 ("man klogd"). 106 107config IP_ROUTE_CLASSID 108 bool 109 110config IP_PNP 111 bool "IP: kernel level autoconfiguration" 112 help 113 This enables automatic configuration of IP addresses of devices and 114 of the routing table during kernel boot, based on either information 115 supplied on the kernel command line or by BOOTP or RARP protocols. 116 You need to say Y only for diskless machines requiring network 117 access to boot (in which case you want to say Y to "Root file system 118 on NFS" as well), because all other machines configure the network 119 in their startup scripts. 120 121config IP_PNP_DHCP 122 bool "IP: DHCP support" 123 depends on IP_PNP 124 ---help--- 125 If you want your Linux box to mount its whole root file system (the 126 one containing the directory /) from some other computer over the 127 net via NFS and you want the IP address of your computer to be 128 discovered automatically at boot time using the DHCP protocol (a 129 special protocol designed for doing this job), say Y here. In case 130 the boot ROM of your network card was designed for booting Linux and 131 does DHCP itself, providing all necessary information on the kernel 132 command line, you can say N here. 133 134 If unsure, say Y. Note that if you want to use DHCP, a DHCP server 135 must be operating on your network. Read 136 <file:Documentation/filesystems/nfs/nfsroot.txt> for details. 137 138config IP_PNP_BOOTP 139 bool "IP: BOOTP support" 140 depends on IP_PNP 141 ---help--- 142 If you want your Linux box to mount its whole root file system (the 143 one containing the directory /) from some other computer over the 144 net via NFS and you want the IP address of your computer to be 145 discovered automatically at boot time using the BOOTP protocol (a 146 special protocol designed for doing this job), say Y here. In case 147 the boot ROM of your network card was designed for booting Linux and 148 does BOOTP itself, providing all necessary information on the kernel 149 command line, you can say N here. If unsure, say Y. Note that if you 150 want to use BOOTP, a BOOTP server must be operating on your network. 151 Read <file:Documentation/filesystems/nfs/nfsroot.txt> for details. 152 153config IP_PNP_RARP 154 bool "IP: RARP support" 155 depends on IP_PNP 156 help 157 If you want your Linux box to mount its whole root file system (the 158 one containing the directory /) from some other computer over the 159 net via NFS and you want the IP address of your computer to be 160 discovered automatically at boot time using the RARP protocol (an 161 older protocol which is being obsoleted by BOOTP and DHCP), say Y 162 here. Note that if you want to use RARP, a RARP server must be 163 operating on your network. Read 164 <file:Documentation/filesystems/nfs/nfsroot.txt> for details. 165 166# not yet ready.. 167# bool ' IP: ARP support' CONFIG_IP_PNP_ARP 168config NET_IPIP 169 tristate "IP: tunneling" 170 select INET_TUNNEL 171 ---help--- 172 Tunneling means encapsulating data of one protocol type within 173 another protocol and sending it over a channel that understands the 174 encapsulating protocol. This particular tunneling driver implements 175 encapsulation of IP within IP, which sounds kind of pointless, but 176 can be useful if you want to make your (or some other) machine 177 appear on a different network than it physically is, or to use 178 mobile-IP facilities (allowing laptops to seamlessly move between 179 networks without changing their IP addresses). 180 181 Saying Y to this option will produce two modules ( = code which can 182 be inserted in and removed from the running kernel whenever you 183 want). Most people won't need this and can say N. 184 185config NET_IPGRE_DEMUX 186 tristate "IP: GRE demultiplexer" 187 help 188 This is helper module to demultiplex GRE packets on GRE version field criteria. 189 Required by ip_gre and pptp modules. 190 191config NET_IPGRE 192 tristate "IP: GRE tunnels over IP" 193 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX 194 help 195 Tunneling means encapsulating data of one protocol type within 196 another protocol and sending it over a channel that understands the 197 encapsulating protocol. This particular tunneling driver implements 198 GRE (Generic Routing Encapsulation) and at this time allows 199 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 200 This driver is useful if the other endpoint is a Cisco router: Cisco 201 likes GRE much better than the other Linux tunneling driver ("IP 202 tunneling" above). In addition, GRE allows multicast redistribution 203 through the tunnel. 204 205config NET_IPGRE_BROADCAST 206 bool "IP: broadcast GRE over IP" 207 depends on IP_MULTICAST && NET_IPGRE 208 help 209 One application of GRE/IP is to construct a broadcast WAN (Wide Area 210 Network), which looks like a normal Ethernet LAN (Local Area 211 Network), but can be distributed all over the Internet. If you want 212 to do that, say Y here and to "IP multicast routing" below. 213 214config IP_MROUTE 215 bool "IP: multicast routing" 216 depends on IP_MULTICAST 217 help 218 This is used if you want your machine to act as a router for IP 219 packets that have several destination addresses. It is needed on the 220 MBONE, a high bandwidth network on top of the Internet which carries 221 audio and video broadcasts. In order to do that, you would most 222 likely run the program mrouted. Information about the multicast 223 capabilities of the various network cards is contained in 224 <file:Documentation/networking/multicast.txt>. If you haven't heard 225 about it, you don't need it. 226 227config IP_MROUTE_MULTIPLE_TABLES 228 bool "IP: multicast policy routing" 229 depends on IP_MROUTE && IP_ADVANCED_ROUTER 230 select FIB_RULES 231 help 232 Normally, a multicast router runs a userspace daemon and decides 233 what to do with a multicast packet based on the source and 234 destination addresses. If you say Y here, the multicast router 235 will also be able to take interfaces and packet marks into 236 account and run multiple instances of userspace daemons 237 simultaneously, each one handling a single table. 238 239 If unsure, say N. 240 241config IP_PIMSM_V1 242 bool "IP: PIM-SM version 1 support" 243 depends on IP_MROUTE 244 help 245 Kernel side support for Sparse Mode PIM (Protocol Independent 246 Multicast) version 1. This multicast routing protocol is used widely 247 because Cisco supports it. You need special software to use it 248 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 249 information about PIM. 250 251 Say Y if you want to use PIM-SM v1. Note that you can say N here if 252 you just want to use Dense Mode PIM. 253 254config IP_PIMSM_V2 255 bool "IP: PIM-SM version 2 support" 256 depends on IP_MROUTE 257 help 258 Kernel side support for Sparse Mode PIM version 2. In order to use 259 this, you need an experimental routing daemon supporting it (pimd or 260 gated-5). This routing protocol is not used widely, so say N unless 261 you want to play with it. 262 263config ARPD 264 bool "IP: ARP daemon support" 265 ---help--- 266 The kernel maintains an internal cache which maps IP addresses to 267 hardware addresses on the local network, so that Ethernet/Token Ring/ 268 etc. frames are sent to the proper address on the physical networking 269 layer. Normally, kernel uses the ARP protocol to resolve these 270 mappings. 271 272 Saying Y here adds support to have an user space daemon to do this 273 resolution instead. This is useful for implementing an alternate 274 address resolution protocol (e.g. NHRP on mGRE tunnels) and also for 275 testing purposes. 276 277 If unsure, say N. 278 279config SYN_COOKIES 280 bool "IP: TCP syncookie support" 281 ---help--- 282 Normal TCP/IP networking is open to an attack known as "SYN 283 flooding". This denial-of-service attack prevents legitimate remote 284 users from being able to connect to your computer during an ongoing 285 attack and requires very little work from the attacker, who can 286 operate from anywhere on the Internet. 287 288 SYN cookies provide protection against this type of attack. If you 289 say Y here, the TCP/IP stack will use a cryptographic challenge 290 protocol known as "SYN cookies" to enable legitimate users to 291 continue to connect, even when your machine is under attack. There 292 is no need for the legitimate users to change their TCP/IP software; 293 SYN cookies work transparently to them. For technical information 294 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 295 296 If you are SYN flooded, the source address reported by the kernel is 297 likely to have been forged by the attacker; it is only reported as 298 an aid in tracing the packets to their actual source and should not 299 be taken as absolute truth. 300 301 SYN cookies may prevent correct error reporting on clients when the 302 server is really overloaded. If this happens frequently better turn 303 them off. 304 305 If you say Y here, you can disable SYN cookies at run time by 306 saying Y to "/proc file system support" and 307 "Sysctl support" below and executing the command 308 309 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 310 311 after the /proc file system has been mounted. 312 313 If unsure, say N. 314 315config INET_AH 316 tristate "IP: AH transformation" 317 select XFRM 318 select CRYPTO 319 select CRYPTO_HMAC 320 select CRYPTO_MD5 321 select CRYPTO_SHA1 322 ---help--- 323 Support for IPsec AH. 324 325 If unsure, say Y. 326 327config INET_ESP 328 tristate "IP: ESP transformation" 329 select XFRM 330 select CRYPTO 331 select CRYPTO_AUTHENC 332 select CRYPTO_HMAC 333 select CRYPTO_MD5 334 select CRYPTO_CBC 335 select CRYPTO_SHA1 336 select CRYPTO_DES 337 ---help--- 338 Support for IPsec ESP. 339 340 If unsure, say Y. 341 342config INET_IPCOMP 343 tristate "IP: IPComp transformation" 344 select INET_XFRM_TUNNEL 345 select XFRM_IPCOMP 346 ---help--- 347 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 348 typically needed for IPsec. 349 350 If unsure, say Y. 351 352config INET_XFRM_TUNNEL 353 tristate 354 select INET_TUNNEL 355 default n 356 357config INET_TUNNEL 358 tristate 359 default n 360 361config INET_XFRM_MODE_TRANSPORT 362 tristate "IP: IPsec transport mode" 363 default y 364 select XFRM 365 ---help--- 366 Support for IPsec transport mode. 367 368 If unsure, say Y. 369 370config INET_XFRM_MODE_TUNNEL 371 tristate "IP: IPsec tunnel mode" 372 default y 373 select XFRM 374 ---help--- 375 Support for IPsec tunnel mode. 376 377 If unsure, say Y. 378 379config INET_XFRM_MODE_BEET 380 tristate "IP: IPsec BEET mode" 381 default y 382 select XFRM 383 ---help--- 384 Support for IPsec BEET mode. 385 386 If unsure, say Y. 387 388config INET_LRO 389 tristate "Large Receive Offload (ipv4/tcp)" 390 default y 391 ---help--- 392 Support for Large Receive Offload (ipv4/tcp). 393 394 If unsure, say Y. 395 396config INET_DIAG 397 tristate "INET: socket monitoring interface" 398 default y 399 ---help--- 400 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 401 native Linux tools such as ss. ss is included in iproute2, currently 402 downloadable at: 403 404 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 405 406 If unsure, say Y. 407 408config INET_TCP_DIAG 409 depends on INET_DIAG 410 def_tristate INET_DIAG 411 412config INET_UDP_DIAG 413 depends on INET_DIAG 414 def_tristate INET_DIAG && IPV6 415 416menuconfig TCP_CONG_ADVANCED 417 bool "TCP: advanced congestion control" 418 ---help--- 419 Support for selection of various TCP congestion control 420 modules. 421 422 Nearly all users can safely say no here, and a safe default 423 selection will be made (CUBIC with new Reno as a fallback). 424 425 If unsure, say N. 426 427if TCP_CONG_ADVANCED 428 429config TCP_CONG_BIC 430 tristate "Binary Increase Congestion (BIC) control" 431 default m 432 ---help--- 433 BIC-TCP is a sender-side only change that ensures a linear RTT 434 fairness under large windows while offering both scalability and 435 bounded TCP-friendliness. The protocol combines two schemes 436 called additive increase and binary search increase. When the 437 congestion window is large, additive increase with a large 438 increment ensures linear RTT fairness as well as good 439 scalability. Under small congestion windows, binary search 440 increase provides TCP friendliness. 441 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 442 443config TCP_CONG_CUBIC 444 tristate "CUBIC TCP" 445 default y 446 ---help--- 447 This is version 2.0 of BIC-TCP which uses a cubic growth function 448 among other techniques. 449 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 450 451config TCP_CONG_WESTWOOD 452 tristate "TCP Westwood+" 453 default m 454 ---help--- 455 TCP Westwood+ is a sender-side only modification of the TCP Reno 456 protocol stack that optimizes the performance of TCP congestion 457 control. It is based on end-to-end bandwidth estimation to set 458 congestion window and slow start threshold after a congestion 459 episode. Using this estimation, TCP Westwood+ adaptively sets a 460 slow start threshold and a congestion window which takes into 461 account the bandwidth used at the time congestion is experienced. 462 TCP Westwood+ significantly increases fairness wrt TCP Reno in 463 wired networks and throughput over wireless links. 464 465config TCP_CONG_HTCP 466 tristate "H-TCP" 467 default m 468 ---help--- 469 H-TCP is a send-side only modifications of the TCP Reno 470 protocol stack that optimizes the performance of TCP 471 congestion control for high speed network links. It uses a 472 modeswitch to change the alpha and beta parameters of TCP Reno 473 based on network conditions and in a way so as to be fair with 474 other Reno and H-TCP flows. 475 476config TCP_CONG_HSTCP 477 tristate "High Speed TCP" 478 depends on EXPERIMENTAL 479 default n 480 ---help--- 481 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 482 A modification to TCP's congestion control mechanism for use 483 with large congestion windows. A table indicates how much to 484 increase the congestion window by when an ACK is received. 485 For more detail see http://www.icir.org/floyd/hstcp.html 486 487config TCP_CONG_HYBLA 488 tristate "TCP-Hybla congestion control algorithm" 489 depends on EXPERIMENTAL 490 default n 491 ---help--- 492 TCP-Hybla is a sender-side only change that eliminates penalization of 493 long-RTT, large-bandwidth connections, like when satellite legs are 494 involved, especially when sharing a common bottleneck with normal 495 terrestrial connections. 496 497config TCP_CONG_VEGAS 498 tristate "TCP Vegas" 499 depends on EXPERIMENTAL 500 default n 501 ---help--- 502 TCP Vegas is a sender-side only change to TCP that anticipates 503 the onset of congestion by estimating the bandwidth. TCP Vegas 504 adjusts the sending rate by modifying the congestion 505 window. TCP Vegas should provide less packet loss, but it is 506 not as aggressive as TCP Reno. 507 508config TCP_CONG_SCALABLE 509 tristate "Scalable TCP" 510 depends on EXPERIMENTAL 511 default n 512 ---help--- 513 Scalable TCP is a sender-side only change to TCP which uses a 514 MIMD congestion control algorithm which has some nice scaling 515 properties, though is known to have fairness issues. 516 See http://www.deneholme.net/tom/scalable/ 517 518config TCP_CONG_LP 519 tristate "TCP Low Priority" 520 depends on EXPERIMENTAL 521 default n 522 ---help--- 523 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 524 to utilize only the excess network bandwidth as compared to the 525 ``fair share`` of bandwidth as targeted by TCP. 526 See http://www-ece.rice.edu/networks/TCP-LP/ 527 528config TCP_CONG_VENO 529 tristate "TCP Veno" 530 depends on EXPERIMENTAL 531 default n 532 ---help--- 533 TCP Veno is a sender-side only enhancement of TCP to obtain better 534 throughput over wireless networks. TCP Veno makes use of state 535 distinguishing to circumvent the difficult judgment of the packet loss 536 type. TCP Veno cuts down less congestion window in response to random 537 loss packets. 538 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 539 540config TCP_CONG_YEAH 541 tristate "YeAH TCP" 542 depends on EXPERIMENTAL 543 select TCP_CONG_VEGAS 544 default n 545 ---help--- 546 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 547 algorithm, which uses a mixed loss/delay approach to compute the 548 congestion window. It's design goals target high efficiency, 549 internal, RTT and Reno fairness, resilience to link loss while 550 keeping network elements load as low as possible. 551 552 For further details look here: 553 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 554 555config TCP_CONG_ILLINOIS 556 tristate "TCP Illinois" 557 depends on EXPERIMENTAL 558 default n 559 ---help--- 560 TCP-Illinois is a sender-side modification of TCP Reno for 561 high speed long delay links. It uses round-trip-time to 562 adjust the alpha and beta parameters to achieve a higher average 563 throughput and maintain fairness. 564 565 For further details see: 566 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 567 568choice 569 prompt "Default TCP congestion control" 570 default DEFAULT_CUBIC 571 help 572 Select the TCP congestion control that will be used by default 573 for all connections. 574 575 config DEFAULT_BIC 576 bool "Bic" if TCP_CONG_BIC=y 577 578 config DEFAULT_CUBIC 579 bool "Cubic" if TCP_CONG_CUBIC=y 580 581 config DEFAULT_HTCP 582 bool "Htcp" if TCP_CONG_HTCP=y 583 584 config DEFAULT_HYBLA 585 bool "Hybla" if TCP_CONG_HYBLA=y 586 587 config DEFAULT_VEGAS 588 bool "Vegas" if TCP_CONG_VEGAS=y 589 590 config DEFAULT_VENO 591 bool "Veno" if TCP_CONG_VENO=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 "hybla" if DEFAULT_HYBLA 614 default "vegas" if DEFAULT_VEGAS 615 default "westwood" if DEFAULT_WESTWOOD 616 default "veno" if DEFAULT_VENO 617 default "reno" if DEFAULT_RENO 618 default "cubic" 619 620config TCP_MD5SIG 621 bool "TCP: MD5 Signature Option support (RFC2385) (EXPERIMENTAL)" 622 depends on EXPERIMENTAL 623 select CRYPTO 624 select CRYPTO_MD5 625 ---help--- 626 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 627 Its main (only?) use is to protect BGP sessions between core routers 628 on the Internet. 629 630 If unsure, say N. 631