net/ipv4/Kconfig

   1 #
   2 # IP configuration
   3 #
   4 config 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/>. For most people, it's safe to say N.
  13
  14 config IP_ADVANCED_ROUTER
  15         bool "IP: advanced router"
  16         ---help---
  17           If you intend to run your Linux box mostly as a router, i.e. as a
  18           computer that forwards and redistributes network packets, say Y; you
  19           will then be presented with several options that allow more precise
  20           control about the routing process.
  21
  22           The answer to this question won't directly affect the kernel:
  23           answering N will just cause the configurator to skip all the
  24           questions about advanced routing.
  25
  26           Note that your box can only act as a router if you enable IP
  27           forwarding in your kernel; you can do that by saying Y to "/proc
  28           file system support" and "Sysctl support" below and executing the
  29           line
  30
  31           echo "1" > /proc/sys/net/ipv4/ip_forward
  32
  33           at boot time after the /proc file system has been mounted.
  34
  35           If you turn on IP forwarding, you should consider the rp_filter, which
  36           automatically rejects incoming packets if the routing table entry
  37           for their source address doesn't match the network interface they're
  38           arriving on. This has security advantages because it prevents the
  39           so-called IP spoofing, however it can pose problems if you use
  40           asymmetric routing (packets from you to a host take a different path
  41           than packets from that host to you) or if you operate a non-routing
  42           host which has several IP addresses on different interfaces. To turn
  43           rp_filter on use:
  44
  45           echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
  46            or
  47           echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
  48
  49           Note that some distributions enable it in startup scripts.
  50           For details about rp_filter strict and loose mode read
  51           <file:Documentation/networking/ip-sysctl.txt>.
  52
  53           If unsure, say N here.
  54
  55 config IP_FIB_TRIE_STATS
  56         bool "FIB TRIE statistics"
  57         depends on IP_ADVANCED_ROUTER
  58         ---help---
  59           Keep track of statistics on structure of FIB TRIE table.
  60           Useful for testing and measuring TRIE performance.
  61
  62 config IP_MULTIPLE_TABLES
  63         bool "IP: policy routing"
  64         depends on IP_ADVANCED_ROUTER
  65         select FIB_RULES
  66         ---help---
  67           Normally, a router decides what to do with a received packet based
  68           solely on the packet's final destination address. If you say Y here,
  69           the Linux router will also be able to take the packet's source
  70           address into account. Furthermore, the TOS (Type-Of-Service) field
  71           of the packet can be used for routing decisions as well.
  72
  73           If you are interested in this, please see the preliminary
  74           documentation at <http://www.compendium.com.ar/policy-routing.txt>
  75           and <ftp://post.tepkom.ru/pub/vol2/Linux/docs/advanced-routing.tex>.
  76           You will need supporting software from
  77           <ftp://ftp.tux.org/pub/net/ip-routing/>.
  78
  79           If unsure, say N.
  80
  81 config IP_ROUTE_MULTIPATH
  82         bool "IP: equal cost multipath"
  83         depends on IP_ADVANCED_ROUTER
  84         help
  85           Normally, the routing tables specify a single action to be taken in
  86           a deterministic manner for a given packet. If you say Y here
  87           however, it becomes possible to attach several actions to a packet
  88           pattern, in effect specifying several alternative paths to travel
  89           for those packets. The router considers all these paths to be of
  90           equal "cost" and chooses one of them in a non-deterministic fashion
  91           if a matching packet arrives.
  92
  93 config IP_ROUTE_VERBOSE
  94         bool "IP: verbose route monitoring"
  95         depends on IP_ADVANCED_ROUTER
  96         help
  97           If you say Y here, which is recommended, then the kernel will print
  98           verbose messages regarding the routing, for example warnings about
  99           received packets which look strange and could be evidence of an
 100           attack or a misconfigured system somewhere. The information is
 101           handled by the klogd daemon which is responsible for kernel messages
 102           ("man klogd").
 103
 104 config IP_ROUTE_CLASSID
 105         bool
 106
 107 config IP_PNP
 108         bool "IP: kernel level autoconfiguration"
 109         help
 110           This enables automatic configuration of IP addresses of devices and
 111           of the routing table during kernel boot, based on either information
 112           supplied on the kernel command line or by BOOTP or RARP protocols.
 113           You need to say Y only for diskless machines requiring network
 114           access to boot (in which case you want to say Y to "Root file system
 115           on NFS" as well), because all other machines configure the network
 116           in their startup scripts.
 117
 118 config IP_PNP_DHCP
 119         bool "IP: DHCP support"
 120         depends on IP_PNP
 121         ---help---
 122           If you want your Linux box to mount its whole root file system (the
 123           one containing the directory /) from some other computer over the
 124           net via NFS and you want the IP address of your computer to be
 125           discovered automatically at boot time using the DHCP protocol (a
 126           special protocol designed for doing this job), say Y here. In case
 127           the boot ROM of your network card was designed for booting Linux and
 128           does DHCP itself, providing all necessary information on the kernel
 129           command line, you can say N here.
 130
 131           If unsure, say Y. Note that if you want to use DHCP, a DHCP server
 132           must be operating on your network.  Read
 133           <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
 134
 135 config IP_PNP_BOOTP
 136         bool "IP: BOOTP support"
 137         depends on IP_PNP
 138         ---help---
 139           If you want your Linux box to mount its whole root file system (the
 140           one containing the directory /) from some other computer over the
 141           net via NFS and you want the IP address of your computer to be
 142           discovered automatically at boot time using the BOOTP protocol (a
 143           special protocol designed for doing this job), say Y here. In case
 144           the boot ROM of your network card was designed for booting Linux and
 145           does BOOTP itself, providing all necessary information on the kernel
 146           command line, you can say N here. If unsure, say Y. Note that if you
 147           want to use BOOTP, a BOOTP server must be operating on your network.
 148           Read <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
 149
 150 config IP_PNP_RARP
 151         bool "IP: RARP support"
 152         depends on IP_PNP
 153         help
 154           If you want your Linux box to mount its whole root file system (the
 155           one containing the directory /) from some other computer over the
 156           net via NFS and you want the IP address of your computer to be
 157           discovered automatically at boot time using the RARP protocol (an
 158           older protocol which is being obsoleted by BOOTP and DHCP), say Y
 159           here. Note that if you want to use RARP, a RARP server must be
 160           operating on your network. Read
 161           <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
 162
 163 config NET_IPIP
 164         tristate "IP: tunneling"
 165         select INET_TUNNEL
 166         select NET_IP_TUNNEL
 167         ---help---
 168           Tunneling means encapsulating data of one protocol type within
 169           another protocol and sending it over a channel that understands the
 170           encapsulating protocol. This particular tunneling driver implements
 171           encapsulation of IP within IP, which sounds kind of pointless, but
 172           can be useful if you want to make your (or some other) machine
 173           appear on a different network than it physically is, or to use
 174           mobile-IP facilities (allowing laptops to seamlessly move between
 175           networks without changing their IP addresses).
 176
 177           Saying Y to this option will produce two modules ( = code which can
 178           be inserted in and removed from the running kernel whenever you
 179           want). Most people won't need this and can say N.
 180
 181 config NET_IPGRE_DEMUX
 182         tristate "IP: GRE demultiplexer"
 183         help
 184          This is helper module to demultiplex GRE packets on GRE version field criteria.
 185          Required by ip_gre and pptp modules.
 186
 187 config NET_IP_TUNNEL
 188         tristate
 189         select DST_CACHE
 190         select GRO_CELLS
 191         default n
 192
 193 config NET_IPGRE
 194         tristate "IP: GRE tunnels over IP"
 195         depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
 196         select NET_IP_TUNNEL
 197         help
 198           Tunneling means encapsulating data of one protocol type within
 199           another protocol and sending it over a channel that understands the
 200           encapsulating protocol. This particular tunneling driver implements
 201           GRE (Generic Routing Encapsulation) and at this time allows
 202           encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
 203           This driver is useful if the other endpoint is a Cisco router: Cisco
 204           likes GRE much better than the other Linux tunneling driver ("IP
 205           tunneling" above). In addition, GRE allows multicast redistribution
 206           through the tunnel.
 207
 208 config NET_IPGRE_BROADCAST
 209         bool "IP: broadcast GRE over IP"
 210         depends on IP_MULTICAST && NET_IPGRE
 211         help
 212           One application of GRE/IP is to construct a broadcast WAN (Wide Area
 213           Network), which looks like a normal Ethernet LAN (Local Area
 214           Network), but can be distributed all over the Internet. If you want
 215           to do that, say Y here and to "IP multicast routing" below.
 216
 217 config IP_MROUTE
 218         bool "IP: multicast routing"
 219         depends on IP_MULTICAST
 220         help
 221           This is used if you want your machine to act as a router for IP
 222           packets that have several destination addresses. It is needed on the
 223           MBONE, a high bandwidth network on top of the Internet which carries
 224           audio and video broadcasts. In order to do that, you would most
 225           likely run the program mrouted. If you haven't heard about it, you
 226           don't need it.
 227
 228 config IP_MROUTE_MULTIPLE_TABLES
 229         bool "IP: multicast policy routing"
 230         depends on IP_MROUTE && IP_ADVANCED_ROUTER
 231         select FIB_RULES
 232         help
 233           Normally, a multicast router runs a userspace daemon and decides
 234           what to do with a multicast packet based on the source and
 235           destination addresses. If you say Y here, the multicast router
 236           will also be able to take interfaces and packet marks into
 237           account and run multiple instances of userspace daemons
 238           simultaneously, each one handling a single table.
 239
 240           If unsure, say N.
 241
 242 config IP_PIMSM_V1
 243         bool "IP: PIM-SM version 1 support"
 244         depends on IP_MROUTE
 245         help
 246           Kernel side support for Sparse Mode PIM (Protocol Independent
 247           Multicast) version 1. This multicast routing protocol is used widely
 248           because Cisco supports it. You need special software to use it
 249           (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
 250           information about PIM.
 251
 252           Say Y if you want to use PIM-SM v1. Note that you can say N here if
 253           you just want to use Dense Mode PIM.
 254
 255 config IP_PIMSM_V2
 256         bool "IP: PIM-SM version 2 support"
 257         depends on IP_MROUTE
 258         help
 259           Kernel side support for Sparse Mode PIM version 2. In order to use
 260           this, you need an experimental routing daemon supporting it (pimd or
 261           gated-5). This routing protocol is not used widely, so say N unless
 262           you want to play with it.
 263
 264 config SYN_COOKIES
 265         bool "IP: TCP syncookie support"
 266         ---help---
 267           Normal TCP/IP networking is open to an attack known as "SYN
 268           flooding". This denial-of-service attack prevents legitimate remote
 269           users from being able to connect to your computer during an ongoing
 270           attack and requires very little work from the attacker, who can
 271           operate from anywhere on the Internet.
 272
 273           SYN cookies provide protection against this type of attack. If you
 274           say Y here, the TCP/IP stack will use a cryptographic challenge
 275           protocol known as "SYN cookies" to enable legitimate users to
 276           continue to connect, even when your machine is under attack. There
 277           is no need for the legitimate users to change their TCP/IP software;
 278           SYN cookies work transparently to them. For technical information
 279           about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
 280
 281           If you are SYN flooded, the source address reported by the kernel is
 282           likely to have been forged by the attacker; it is only reported as
 283           an aid in tracing the packets to their actual source and should not
 284           be taken as absolute truth.
 285
 286           SYN cookies may prevent correct error reporting on clients when the
 287           server is really overloaded. If this happens frequently better turn
 288           them off.
 289
 290           If you say Y here, you can disable SYN cookies at run time by
 291           saying Y to "/proc file system support" and
 292           "Sysctl support" below and executing the command
 293
 294           echo 0 > /proc/sys/net/ipv4/tcp_syncookies
 295
 296           after the /proc file system has been mounted.
 297
 298           If unsure, say N.
 299
 300 config NET_IPVTI
 301         tristate "Virtual (secure) IP: tunneling"
 302         select INET_TUNNEL
 303         select NET_IP_TUNNEL
 304         depends on INET_XFRM_MODE_TUNNEL
 305         ---help---
 306           Tunneling means encapsulating data of one protocol type within
 307           another protocol and sending it over a channel that understands the
 308           encapsulating protocol. This can be used with xfrm mode tunnel to give
 309           the notion of a secure tunnel for IPSEC and then use routing protocol
 310           on top.
 311
 312 config NET_UDP_TUNNEL
 313         tristate
 314         select NET_IP_TUNNEL
 315         default n
 316
 317 config NET_FOU
 318         tristate "IP: Foo (IP protocols) over UDP"
 319         select XFRM
 320         select NET_UDP_TUNNEL
 321         ---help---
 322           Foo over UDP allows any IP protocol to be directly encapsulated
 323           over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
 324           network mechanisms and optimizations for UDP (such as ECMP
 325           and RSS) can be leveraged to provide better service.
 326
 327 config NET_FOU_IP_TUNNELS
 328         bool "IP: FOU encapsulation of IP tunnels"
 329         depends on NET_IPIP || NET_IPGRE || IPV6_SIT
 330         select NET_FOU
 331         ---help---
 332           Allow configuration of FOU or GUE encapsulation for IP tunnels.
 333           When this option is enabled IP tunnels can be configured to use
 334           FOU or GUE encapsulation.
 335
 336 config INET_AH
 337         tristate "IP: AH transformation"
 338         select XFRM_ALGO
 339         select CRYPTO
 340         select CRYPTO_HMAC
 341         select CRYPTO_MD5
 342         select CRYPTO_SHA1
 343         ---help---
 344           Support for IPsec AH.
 345
 346           If unsure, say Y.
 347
 348 config INET_ESP
 349         tristate "IP: ESP transformation"
 350         select XFRM_ALGO
 351         select CRYPTO
 352         select CRYPTO_AUTHENC
 353         select CRYPTO_HMAC
 354         select CRYPTO_MD5
 355         select CRYPTO_CBC
 356         select CRYPTO_SHA1
 357         select CRYPTO_DES
 358         select CRYPTO_ECHAINIV
 359         ---help---
 360           Support for IPsec ESP.
 361
 362           If unsure, say Y.
 363
 364 config INET_ESP_OFFLOAD
 365         tristate "IP: ESP transformation offload"
 366         depends on INET_ESP
 367         select XFRM_OFFLOAD
 368         default n
 369         ---help---
 370           Support for ESP transformation offload. This makes sense
 371           only if this system really does IPsec and want to do it
 372           with high throughput. A typical desktop system does not
 373           need it, even if it does IPsec.
 374
 375           If unsure, say N.
 376
 377 config INET_IPCOMP
 378         tristate "IP: IPComp transformation"
 379         select INET_XFRM_TUNNEL
 380         select XFRM_IPCOMP
 381         ---help---
 382           Support for IP Payload Compression Protocol (IPComp) (RFC3173),
 383           typically needed for IPsec.
 384
 385           If unsure, say Y.
 386
 387 config INET_XFRM_TUNNEL
 388         tristate
 389         select INET_TUNNEL
 390         default n
 391
 392 config INET_TUNNEL
 393         tristate
 394         default n
 395
 396 config INET_XFRM_MODE_TRANSPORT
 397         tristate "IP: IPsec transport mode"
 398         default y
 399         select XFRM
 400         ---help---
 401           Support for IPsec transport mode.
 402
 403           If unsure, say Y.
 404
 405 config INET_XFRM_MODE_TUNNEL
 406         tristate "IP: IPsec tunnel mode"
 407         default y
 408         select XFRM
 409         ---help---
 410           Support for IPsec tunnel mode.
 411
 412           If unsure, say Y.
 413
 414 config INET_XFRM_MODE_BEET
 415         tristate "IP: IPsec BEET mode"
 416         default y
 417         select XFRM
 418         ---help---
 419           Support for IPsec BEET mode.
 420
 421           If unsure, say Y.
 422
 423 config 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:
 430
 431             http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
 432
 433           If unsure, say Y.
 434
 435 config INET_TCP_DIAG
 436         depends on INET_DIAG
 437         def_tristate INET_DIAG
 438
 439 config INET_UDP_DIAG
 440         tristate "UDP: socket monitoring interface"
 441         depends on INET_DIAG && (IPV6 || IPV6=n)
 442         default n
 443         ---help---
 444           Support for UDP socket monitoring interface used by the ss tool.
 445           If unsure, say Y.
 446
 447 config INET_RAW_DIAG
 448         tristate "RAW: socket monitoring interface"
 449         depends on INET_DIAG && (IPV6 || IPV6=n)
 450         default n
 451         ---help---
 452           Support for RAW socket monitoring interface used by the ss tool.
 453           If unsure, say Y.
 454
 455 config INET_DIAG_DESTROY
 456         bool "INET: allow privileged process to administratively close sockets"
 457         depends on INET_DIAG
 458         default n
 459         ---help---
 460           Provides a SOCK_DESTROY operation that allows privileged processes
 461           (e.g., a connection manager or a network administration tool such as
 462           ss) to close sockets opened by other processes. Closing a socket in
 463           this way interrupts any blocking read/write/connect operations on
 464           the socket and causes future socket calls to behave as if the socket
 465           had been disconnected.
 466           If unsure, say N.
 467
 468 menuconfig TCP_CONG_ADVANCED
 469         bool "TCP: advanced congestion control"
 470         ---help---
 471           Support for selection of various TCP congestion control
 472           modules.
 473
 474           Nearly all users can safely say no here, and a safe default
 475           selection will be made (CUBIC with new Reno as a fallback).
 476
 477           If unsure, say N.
 478
 479 if TCP_CONG_ADVANCED
 480
 481 config TCP_CONG_BIC
 482         tristate "Binary Increase Congestion (BIC) control"
 483         default m
 484         ---help---
 485         BIC-TCP is a sender-side only change that ensures a linear RTT
 486         fairness under large windows while offering both scalability and
 487         bounded TCP-friendliness. The protocol combines two schemes
 488         called additive increase and binary search increase. When the
 489         congestion window is large, additive increase with a large
 490         increment ensures linear RTT fairness as well as good
 491         scalability. Under small congestion windows, binary search
 492         increase provides TCP friendliness.
 493         See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
 494
 495 config TCP_CONG_CUBIC
 496         tristate "CUBIC TCP"
 497         default y
 498         ---help---
 499         This is version 2.0 of BIC-TCP which uses a cubic growth function
 500         among other techniques.
 501         See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
 502
 503 config TCP_CONG_WESTWOOD
 504         tristate "TCP Westwood+"
 505         default m
 506         ---help---
 507         TCP Westwood+ is a sender-side only modification of the TCP Reno
 508         protocol stack that optimizes the performance of TCP congestion
 509         control. It is based on end-to-end bandwidth estimation to set
 510         congestion window and slow start threshold after a congestion
 511         episode. Using this estimation, TCP Westwood+ adaptively sets a
 512         slow start threshold and a congestion window which takes into
 513         account the bandwidth used  at the time congestion is experienced.
 514         TCP Westwood+ significantly increases fairness wrt TCP Reno in
 515         wired networks and throughput over wireless links.
 516
 517 config TCP_CONG_HTCP
 518         tristate "H-TCP"
 519         default m
 520         ---help---
 521         H-TCP is a send-side only modifications of the TCP Reno
 522         protocol stack that optimizes the performance of TCP
 523         congestion control for high speed network links. It uses a
 524         modeswitch to change the alpha and beta parameters of TCP Reno
 525         based on network conditions and in a way so as to be fair with
 526         other Reno and H-TCP flows.
 527
 528 config TCP_CONG_HSTCP
 529         tristate "High Speed TCP"
 530         default n
 531         ---help---
 532         Sally Floyd's High Speed TCP (RFC 3649) congestion control.
 533         A modification to TCP's congestion control mechanism for use
 534         with large congestion windows. A table indicates how much to
 535         increase the congestion window by when an ACK is received.
 536         For more detail see http://www.icir.org/floyd/hstcp.html
 537
 538 config TCP_CONG_HYBLA
 539         tristate "TCP-Hybla congestion control algorithm"
 540         default n
 541         ---help---
 542         TCP-Hybla is a sender-side only change that eliminates penalization of
 543         long-RTT, large-bandwidth connections, like when satellite legs are
 544         involved, especially when sharing a common bottleneck with normal
 545         terrestrial connections.
 546
 547 config TCP_CONG_VEGAS
 548         tristate "TCP Vegas"
 549         default n
 550         ---help---
 551         TCP Vegas is a sender-side only change to TCP that anticipates
 552         the onset of congestion by estimating the bandwidth. TCP Vegas
 553         adjusts the sending rate by modifying the congestion
 554         window. TCP Vegas should provide less packet loss, but it is
 555         not as aggressive as TCP Reno.
 556
 557 config TCP_CONG_NV
 558        tristate "TCP NV"
 559        default n
 560        ---help---
 561        TCP NV is a follow up to TCP Vegas. It has been modified to deal with
 562        10G networks, measurement noise introduced by LRO, GRO and interrupt
 563        coalescence. In addition, it will decrease its cwnd multiplicatively
 564        instead of linearly.
 565
 566        Note that in general congestion avoidance (cwnd decreased when # packets
 567        queued grows) cannot coexist with congestion control (cwnd decreased only
 568        when there is packet loss) due to fairness issues. One scenario when they
 569        can coexist safely is when the CA flows have RTTs << CC flows RTTs.
 570
 571        For further details see http://www.brakmo.org/networking/tcp-nv/
 572
 573 config TCP_CONG_SCALABLE
 574         tristate "Scalable TCP"
 575         default n
 576         ---help---
 577         Scalable TCP is a sender-side only change to TCP which uses a
 578         MIMD congestion control algorithm which has some nice scaling
 579         properties, though is known to have fairness issues.
 580         See http://www.deneholme.net/tom/scalable/
 581
 582 config TCP_CONG_LP
 583         tristate "TCP Low Priority"
 584         default n
 585         ---help---
 586         TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
 587         to utilize only the excess network bandwidth as compared to the
 588         ``fair share`` of bandwidth as targeted by TCP.
 589         See http://www-ece.rice.edu/networks/TCP-LP/
 590
 591 config TCP_CONG_VENO
 592         tristate "TCP Veno"
 593         default n
 594         ---help---
 595         TCP Veno is a sender-side only enhancement of TCP to obtain better
 596         throughput over wireless networks. TCP Veno makes use of state
 597         distinguishing to circumvent the difficult judgment of the packet loss
 598         type. TCP Veno cuts down less congestion window in response to random
 599         loss packets.
 600         See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
 601
 602 config TCP_CONG_YEAH
 603         tristate "YeAH TCP"
 604         select TCP_CONG_VEGAS
 605         default n
 606         ---help---
 607         YeAH-TCP is a sender-side high-speed enabled TCP congestion control
 608         algorithm, which uses a mixed loss/delay approach to compute the
 609         congestion window. It's design goals target high efficiency,
 610         internal, RTT and Reno fairness, resilience to link loss while
 611         keeping network elements load as low as possible.
 612
 613         For further details look here:
 614           http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
 615
 616 config TCP_CONG_ILLINOIS
 617         tristate "TCP Illinois"
 618         default n
 619         ---help---
 620         TCP-Illinois is a sender-side modification of TCP Reno for
 621         high speed long delay links. It uses round-trip-time to
 622         adjust the alpha and beta parameters to achieve a higher average
 623         throughput and maintain fairness.
 624
 625         For further details see:
 626           http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
 627
 628 config TCP_CONG_DCTCP
 629         tristate "DataCenter TCP (DCTCP)"
 630         default n
 631         ---help---
 632         DCTCP leverages Explicit Congestion Notification (ECN) in the network to
 633         provide multi-bit feedback to the end hosts. It is designed to provide:
 634
 635         - High burst tolerance (incast due to partition/aggregate),
 636         - Low latency (short flows, queries),
 637         - High throughput (continuous data updates, large file transfers) with
 638           commodity, shallow-buffered switches.
 639
 640         All switches in the data center network running DCTCP must support
 641         ECN marking and be configured for marking when reaching defined switch
 642         buffer thresholds. The default ECN marking threshold heuristic for
 643         DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
 644         (~100KB) at 10Gbps, but might need further careful tweaking.
 645
 646         For further details see:
 647           http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
 648
 649 config TCP_CONG_CDG
 650         tristate "CAIA Delay-Gradient (CDG)"
 651         default n
 652         ---help---
 653         CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
 654         the TCP sender in order to:
 655
 656           o Use the delay gradient as a congestion signal.
 657           o Back off with an average probability that is independent of the RTT.
 658           o Coexist with flows that use loss-based congestion control.
 659           o Tolerate packet loss unrelated to congestion.
 660
 661         For further details see:
 662           D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
 663           delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg
 664
 665 config TCP_CONG_BBR
 666         tristate "BBR TCP"
 667         default n
 668         ---help---
 669
 670         BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to
 671         maximize network utilization and minimize queues. It builds an explicit
 672         model of the the bottleneck delivery rate and path round-trip
 673         propagation delay. It tolerates packet loss and delay unrelated to
 674         congestion. It can operate over LAN, WAN, cellular, wifi, or cable
 675         modem links. It can coexist with flows that use loss-based congestion
 676         control, and can operate with shallow buffers, deep buffers,
 677         bufferbloat, policers, or AQM schemes that do not provide a delay
 678         signal. It requires the fq ("Fair Queue") pacing packet scheduler.
 679
 680 choice
 681         prompt "Default TCP congestion control"
 682         default DEFAULT_CUBIC
 683         help
 684           Select the TCP congestion control that will be used by default
 685           for all connections.
 686
 687         config DEFAULT_BIC
 688                 bool "Bic" if TCP_CONG_BIC=y
 689
 690         config DEFAULT_CUBIC
 691                 bool "Cubic" if TCP_CONG_CUBIC=y
 692
 693         config DEFAULT_HTCP
 694                 bool "Htcp" if TCP_CONG_HTCP=y
 695
 696         config DEFAULT_HYBLA
 697                 bool "Hybla" if TCP_CONG_HYBLA=y
 698
 699         config DEFAULT_VEGAS
 700                 bool "Vegas" if TCP_CONG_VEGAS=y
 701
 702         config DEFAULT_VENO
 703                 bool "Veno" if TCP_CONG_VENO=y
 704
 705         config DEFAULT_WESTWOOD
 706                 bool "Westwood" if TCP_CONG_WESTWOOD=y
 707
 708         config DEFAULT_DCTCP
 709                 bool "DCTCP" if TCP_CONG_DCTCP=y
 710
 711         config DEFAULT_CDG
 712                 bool "CDG" if TCP_CONG_CDG=y
 713
 714         config DEFAULT_BBR
 715                 bool "BBR" if TCP_CONG_BBR=y
 716
 717         config DEFAULT_RENO
 718                 bool "Reno"
 719 endchoice
 720
 721 endif
 722
 723 config TCP_CONG_CUBIC
 724         tristate
 725         depends on !TCP_CONG_ADVANCED
 726         default y
 727
 728 config DEFAULT_TCP_CONG
 729         string
 730         default "bic" if DEFAULT_BIC
 731         default "cubic" if DEFAULT_CUBIC
 732         default "htcp" if DEFAULT_HTCP
 733         default "hybla" if DEFAULT_HYBLA
 734         default "vegas" if DEFAULT_VEGAS
 735         default "westwood" if DEFAULT_WESTWOOD
 736         default "veno" if DEFAULT_VENO
 737         default "reno" if DEFAULT_RENO
 738         default "dctcp" if DEFAULT_DCTCP
 739         default "cdg" if DEFAULT_CDG
 740         default "bbr" if DEFAULT_BBR
 741         default "cubic"
 742
 743 config TCP_MD5SIG
 744         bool "TCP: MD5 Signature Option support (RFC2385)"
 745         select CRYPTO
 746         select CRYPTO_MD5
 747         ---help---
 748           RFC2385 specifies a method of giving MD5 protection to TCP sessions.
 749           Its main (only?) use is to protect BGP sessions between core routers
 750           on the Internet.
 751
 752           If unsure, say N.