1# SPDX-License-Identifier: GPL-2.0-only 2# 3# IP configuration 4# 5config IP_MULTICAST 6 bool "IP: multicasting" 7 help 8 This is code for addressing several networked computers at once, 9 enlarging your kernel by about 2 KB. You need multicasting if you 10 intend to participate in the MBONE, a high bandwidth network on top 11 of the Internet which carries audio and video broadcasts. More 12 information about the MBONE is on the WWW at 13 <http://www.savetz.com/mbone/>. For most people, it's safe to say N. 14 15config IP_ADVANCED_ROUTER 16 bool "IP: advanced router" 17 help 18 If you intend to run your Linux box mostly as a router, i.e. as a 19 computer that forwards and redistributes network packets, say Y; you 20 will then be presented with several options that allow more precise 21 control about the routing process. 22 23 The answer to this question won't directly affect the kernel: 24 answering N will just cause the configurator to skip all the 25 questions about advanced routing. 26 27 Note that your box can only act as a router if you enable IP 28 forwarding in your kernel; you can do that by saying Y to "/proc 29 file system support" and "Sysctl support" below and executing the 30 line 31 32 echo "1" > /proc/sys/net/ipv4/ip_forward 33 34 at boot time after the /proc file system has been mounted. 35 36 If you turn on IP forwarding, you should consider the rp_filter, which 37 automatically rejects incoming packets if the routing table entry 38 for their source address doesn't match the network interface they're 39 arriving on. This has security advantages because it prevents the 40 so-called IP spoofing, however it can pose problems if you use 41 asymmetric routing (packets from you to a host take a different path 42 than packets from that host to you) or if you operate a non-routing 43 host which has several IP addresses on different interfaces. To turn 44 rp_filter on use: 45 46 echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter 47 or 48 echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter 49 50 Note that some distributions enable it in startup scripts. 51 For details about rp_filter strict and loose mode read 52 <file:Documentation/networking/ip-sysctl.rst>. 53 54 If unsure, say N here. 55 56config IP_FIB_TRIE_STATS 57 bool "FIB TRIE statistics" 58 depends on IP_ADVANCED_ROUTER 59 help 60 Keep track of statistics on structure of FIB TRIE table. 61 Useful for testing and measuring TRIE performance. 62 63config IP_MULTIPLE_TABLES 64 bool "IP: policy routing" 65 depends on IP_ADVANCED_ROUTER 66 select FIB_RULES 67 help 68 Normally, a router decides what to do with a received packet based 69 solely on the packet's final destination address. If you say Y here, 70 the Linux router will also be able to take the packet's source 71 address into account. Furthermore, the TOS (Type-Of-Service) field 72 of the packet can be used for routing decisions as well. 73 74 If you need more information, see the Linux Advanced 75 Routing and Traffic Control documentation at 76 <http://lartc.org/howto/lartc.rpdb.html> 77 78 If unsure, say N. 79 80config IP_ROUTE_MULTIPATH 81 bool "IP: equal cost multipath" 82 depends on IP_ADVANCED_ROUTER 83 help 84 Normally, the routing tables specify a single action to be taken in 85 a deterministic manner for a given packet. If you say Y here 86 however, it becomes possible to attach several actions to a packet 87 pattern, in effect specifying several alternative paths to travel 88 for those packets. The router considers all these paths to be of 89 equal "cost" and chooses one of them in a non-deterministic fashion 90 if a matching packet arrives. 91 92config IP_ROUTE_VERBOSE 93 bool "IP: verbose route monitoring" 94 depends on IP_ADVANCED_ROUTER 95 help 96 If you say Y here, which is recommended, then the kernel will print 97 verbose messages regarding the routing, for example warnings about 98 received packets which look strange and could be evidence of an 99 attack or a misconfigured system somewhere. The information is 100 handled by the klogd daemon which is responsible for kernel messages 101 ("man klogd"). 102 103config IP_ROUTE_CLASSID 104 bool 105 106config IP_PNP 107 bool "IP: kernel level autoconfiguration" 108 help 109 This enables automatic configuration of IP addresses of devices and 110 of the routing table during kernel boot, based on either information 111 supplied on the kernel command line or by BOOTP or RARP protocols. 112 You need to say Y only for diskless machines requiring network 113 access to boot (in which case you want to say Y to "Root file system 114 on NFS" as well), because all other machines configure the network 115 in their startup scripts. 116 117config IP_PNP_DHCP 118 bool "IP: DHCP support" 119 depends on IP_PNP 120 help 121 If you want your Linux box to mount its whole root file system (the 122 one containing the directory /) from some other computer over the 123 net via NFS and you want the IP address of your computer to be 124 discovered automatically at boot time using the DHCP protocol (a 125 special protocol designed for doing this job), say Y here. In case 126 the boot ROM of your network card was designed for booting Linux and 127 does DHCP itself, providing all necessary information on the kernel 128 command line, you can say N here. 129 130 If unsure, say Y. Note that if you want to use DHCP, a DHCP server 131 must be operating on your network. Read 132 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details. 133 134config IP_PNP_BOOTP 135 bool "IP: BOOTP support" 136 depends on IP_PNP 137 help 138 If you want your Linux box to mount its whole root file system (the 139 one containing the directory /) from some other computer over the 140 net via NFS and you want the IP address of your computer to be 141 discovered automatically at boot time using the BOOTP protocol (a 142 special protocol designed for doing this job), say Y here. In case 143 the boot ROM of your network card was designed for booting Linux and 144 does BOOTP itself, providing all necessary information on the kernel 145 command line, you can say N here. If unsure, say Y. Note that if you 146 want to use BOOTP, a BOOTP server must be operating on your network. 147 Read <file:Documentation/admin-guide/nfs/nfsroot.rst> for details. 148 149config IP_PNP_RARP 150 bool "IP: RARP support" 151 depends on IP_PNP 152 help 153 If you want your Linux box to mount its whole root file system (the 154 one containing the directory /) from some other computer over the 155 net via NFS and you want the IP address of your computer to be 156 discovered automatically at boot time using the RARP protocol (an 157 older protocol which is being obsoleted by BOOTP and DHCP), say Y 158 here. Note that if you want to use RARP, a RARP server must be 159 operating on your network. Read 160 <file:Documentation/admin-guide/nfs/nfsroot.rst> for details. 161 162config NET_IPIP 163 tristate "IP: tunneling" 164 select INET_TUNNEL 165 select NET_IP_TUNNEL 166 help 167 Tunneling means encapsulating data of one protocol type within 168 another protocol and sending it over a channel that understands the 169 encapsulating protocol. This particular tunneling driver implements 170 encapsulation of IP within IP, which sounds kind of pointless, but 171 can be useful if you want to make your (or some other) machine 172 appear on a different network than it physically is, or to use 173 mobile-IP facilities (allowing laptops to seamlessly move between 174 networks without changing their IP addresses). 175 176 Saying Y to this option will produce two modules ( = code which can 177 be inserted in and removed from the running kernel whenever you 178 want). Most people won't need this and can say N. 179 180config NET_IPGRE_DEMUX 181 tristate "IP: GRE demultiplexer" 182 help 183 This is helper module to demultiplex GRE packets on GRE version field criteria. 184 Required by ip_gre and pptp modules. 185 186config NET_IP_TUNNEL 187 tristate 188 select DST_CACHE 189 select GRO_CELLS 190 default n 191 192config NET_IPGRE 193 tristate "IP: GRE tunnels over IP" 194 depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX 195 select NET_IP_TUNNEL 196 help 197 Tunneling means encapsulating data of one protocol type within 198 another protocol and sending it over a channel that understands the 199 encapsulating protocol. This particular tunneling driver implements 200 GRE (Generic Routing Encapsulation) and at this time allows 201 encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure. 202 This driver is useful if the other endpoint is a Cisco router: Cisco 203 likes GRE much better than the other Linux tunneling driver ("IP 204 tunneling" above). In addition, GRE allows multicast redistribution 205 through the tunnel. 206 207config NET_IPGRE_BROADCAST 208 bool "IP: broadcast GRE over IP" 209 depends on IP_MULTICAST && NET_IPGRE 210 help 211 One application of GRE/IP is to construct a broadcast WAN (Wide Area 212 Network), which looks like a normal Ethernet LAN (Local Area 213 Network), but can be distributed all over the Internet. If you want 214 to do that, say Y here and to "IP multicast routing" below. 215 216config IP_MROUTE_COMMON 217 bool 218 depends on IP_MROUTE || IPV6_MROUTE 219 220config IP_MROUTE 221 bool "IP: multicast routing" 222 depends on IP_MULTICAST 223 select IP_MROUTE_COMMON 224 help 225 This is used if you want your machine to act as a router for IP 226 packets that have several destination addresses. It is needed on the 227 MBONE, a high bandwidth network on top of the Internet which carries 228 audio and video broadcasts. In order to do that, you would most 229 likely run the program mrouted. If you haven't heard about it, you 230 don't need it. 231 232config IP_MROUTE_MULTIPLE_TABLES 233 bool "IP: multicast policy routing" 234 depends on IP_MROUTE && IP_ADVANCED_ROUTER 235 select FIB_RULES 236 help 237 Normally, a multicast router runs a userspace daemon and decides 238 what to do with a multicast packet based on the source and 239 destination addresses. If you say Y here, the multicast router 240 will also be able to take interfaces and packet marks into 241 account and run multiple instances of userspace daemons 242 simultaneously, each one handling a single table. 243 244 If unsure, say N. 245 246config IP_PIMSM_V1 247 bool "IP: PIM-SM version 1 support" 248 depends on IP_MROUTE 249 help 250 Kernel side support for Sparse Mode PIM (Protocol Independent 251 Multicast) version 1. This multicast routing protocol is used widely 252 because Cisco supports it. You need special software to use it 253 (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more 254 information about PIM. 255 256 Say Y if you want to use PIM-SM v1. Note that you can say N here if 257 you just want to use Dense Mode PIM. 258 259config IP_PIMSM_V2 260 bool "IP: PIM-SM version 2 support" 261 depends on IP_MROUTE 262 help 263 Kernel side support for Sparse Mode PIM version 2. In order to use 264 this, you need an experimental routing daemon supporting it (pimd or 265 gated-5). This routing protocol is not used widely, so say N unless 266 you want to play with it. 267 268config SYN_COOKIES 269 bool "IP: TCP syncookie support" 270 help 271 Normal TCP/IP networking is open to an attack known as "SYN 272 flooding". This denial-of-service attack prevents legitimate remote 273 users from being able to connect to your computer during an ongoing 274 attack and requires very little work from the attacker, who can 275 operate from anywhere on the Internet. 276 277 SYN cookies provide protection against this type of attack. If you 278 say Y here, the TCP/IP stack will use a cryptographic challenge 279 protocol known as "SYN cookies" to enable legitimate users to 280 continue to connect, even when your machine is under attack. There 281 is no need for the legitimate users to change their TCP/IP software; 282 SYN cookies work transparently to them. For technical information 283 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 284 285 If you are SYN flooded, the source address reported by the kernel is 286 likely to have been forged by the attacker; it is only reported as 287 an aid in tracing the packets to their actual source and should not 288 be taken as absolute truth. 289 290 SYN cookies may prevent correct error reporting on clients when the 291 server is really overloaded. If this happens frequently better turn 292 them off. 293 294 If you say Y here, you can disable SYN cookies at run time by 295 saying Y to "/proc file system support" and 296 "Sysctl support" below and executing the command 297 298 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 299 300 after the /proc file system has been mounted. 301 302 If unsure, say N. 303 304config NET_IPVTI 305 tristate "Virtual (secure) IP: tunneling" 306 depends on IPV6 || IPV6=n 307 select INET_TUNNEL 308 select NET_IP_TUNNEL 309 select XFRM 310 help 311 Tunneling means encapsulating data of one protocol type within 312 another protocol and sending it over a channel that understands the 313 encapsulating protocol. This can be used with xfrm mode tunnel to give 314 the notion of a secure tunnel for IPSEC and then use routing protocol 315 on top. 316 317config NET_UDP_TUNNEL 318 tristate 319 select NET_IP_TUNNEL 320 default n 321 322config NET_FOU 323 tristate "IP: Foo (IP protocols) over UDP" 324 select XFRM 325 select NET_UDP_TUNNEL 326 help 327 Foo over UDP allows any IP protocol to be directly encapsulated 328 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP 329 network mechanisms and optimizations for UDP (such as ECMP 330 and RSS) can be leveraged to provide better service. 331 332config NET_FOU_IP_TUNNELS 333 bool "IP: FOU encapsulation of IP tunnels" 334 depends on NET_IPIP || NET_IPGRE || IPV6_SIT 335 select NET_FOU 336 help 337 Allow configuration of FOU or GUE encapsulation for IP tunnels. 338 When this option is enabled IP tunnels can be configured to use 339 FOU or GUE encapsulation. 340 341config INET_AH 342 tristate "IP: AH transformation" 343 select XFRM_ALGO 344 select CRYPTO 345 select CRYPTO_HMAC 346 select CRYPTO_MD5 347 select CRYPTO_SHA1 348 help 349 Support for IPsec AH. 350 351 If unsure, say Y. 352 353config INET_ESP 354 tristate "IP: ESP transformation" 355 select XFRM_ALGO 356 select CRYPTO 357 select CRYPTO_AUTHENC 358 select CRYPTO_HMAC 359 select CRYPTO_MD5 360 select CRYPTO_CBC 361 select CRYPTO_SHA1 362 select CRYPTO_DES 363 select CRYPTO_ECHAINIV 364 help 365 Support for IPsec ESP. 366 367 If unsure, say Y. 368 369config INET_ESP_OFFLOAD 370 tristate "IP: ESP transformation offload" 371 depends on INET_ESP 372 select XFRM_OFFLOAD 373 default n 374 help 375 Support for ESP transformation offload. This makes sense 376 only if this system really does IPsec and want to do it 377 with high throughput. A typical desktop system does not 378 need it, even if it does IPsec. 379 380 If unsure, say N. 381 382config INET_ESPINTCP 383 bool "IP: ESP in TCP encapsulation (RFC 8229)" 384 depends on XFRM && INET_ESP 385 select STREAM_PARSER 386 select NET_SOCK_MSG 387 select XFRM_ESPINTCP 388 help 389 Support for RFC 8229 encapsulation of ESP and IKE over 390 TCP/IPv4 sockets. 391 392 If unsure, say N. 393 394config INET_IPCOMP 395 tristate "IP: IPComp transformation" 396 select INET_XFRM_TUNNEL 397 select XFRM_IPCOMP 398 help 399 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 400 typically needed for IPsec. 401 402 If unsure, say Y. 403 404config INET_XFRM_TUNNEL 405 tristate 406 select INET_TUNNEL 407 default n 408 409config INET_TUNNEL 410 tristate 411 default n 412 413config INET_DIAG 414 tristate "INET: socket monitoring interface" 415 default y 416 help 417 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 418 native Linux tools such as ss. ss is included in iproute2, currently 419 downloadable at: 420 421 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 422 423 If unsure, say Y. 424 425config INET_TCP_DIAG 426 depends on INET_DIAG 427 def_tristate INET_DIAG 428 429config INET_UDP_DIAG 430 tristate "UDP: socket monitoring interface" 431 depends on INET_DIAG && (IPV6 || IPV6=n) 432 default n 433 help 434 Support for UDP socket monitoring interface used by the ss tool. 435 If unsure, say Y. 436 437config INET_RAW_DIAG 438 tristate "RAW: socket monitoring interface" 439 depends on INET_DIAG && (IPV6 || IPV6=n) 440 default n 441 help 442 Support for RAW socket monitoring interface used by the ss tool. 443 If unsure, say Y. 444 445config INET_DIAG_DESTROY 446 bool "INET: allow privileged process to administratively close sockets" 447 depends on INET_DIAG 448 default n 449 help 450 Provides a SOCK_DESTROY operation that allows privileged processes 451 (e.g., a connection manager or a network administration tool such as 452 ss) to close sockets opened by other processes. Closing a socket in 453 this way interrupts any blocking read/write/connect operations on 454 the socket and causes future socket calls to behave as if the socket 455 had been disconnected. 456 If unsure, say N. 457 458menuconfig TCP_CONG_ADVANCED 459 bool "TCP: advanced congestion control" 460 help 461 Support for selection of various TCP congestion control 462 modules. 463 464 Nearly all users can safely say no here, and a safe default 465 selection will be made (CUBIC with new Reno as a fallback). 466 467 If unsure, say N. 468 469if TCP_CONG_ADVANCED 470 471config TCP_CONG_BIC 472 tristate "Binary Increase Congestion (BIC) control" 473 default m 474 help 475 BIC-TCP is a sender-side only change that ensures a linear RTT 476 fairness under large windows while offering both scalability and 477 bounded TCP-friendliness. The protocol combines two schemes 478 called additive increase and binary search increase. When the 479 congestion window is large, additive increase with a large 480 increment ensures linear RTT fairness as well as good 481 scalability. Under small congestion windows, binary search 482 increase provides TCP friendliness. 483 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 484 485config TCP_CONG_CUBIC 486 tristate "CUBIC TCP" 487 default y 488 help 489 This is version 2.0 of BIC-TCP which uses a cubic growth function 490 among other techniques. 491 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 492 493config TCP_CONG_WESTWOOD 494 tristate "TCP Westwood+" 495 default m 496 help 497 TCP Westwood+ is a sender-side only modification of the TCP Reno 498 protocol stack that optimizes the performance of TCP congestion 499 control. It is based on end-to-end bandwidth estimation to set 500 congestion window and slow start threshold after a congestion 501 episode. Using this estimation, TCP Westwood+ adaptively sets a 502 slow start threshold and a congestion window which takes into 503 account the bandwidth used at the time congestion is experienced. 504 TCP Westwood+ significantly increases fairness wrt TCP Reno in 505 wired networks and throughput over wireless links. 506 507config TCP_CONG_HTCP 508 tristate "H-TCP" 509 default m 510 help 511 H-TCP is a send-side only modifications of the TCP Reno 512 protocol stack that optimizes the performance of TCP 513 congestion control for high speed network links. It uses a 514 modeswitch to change the alpha and beta parameters of TCP Reno 515 based on network conditions and in a way so as to be fair with 516 other Reno and H-TCP flows. 517 518config TCP_CONG_HSTCP 519 tristate "High Speed TCP" 520 default n 521 help 522 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 523 A modification to TCP's congestion control mechanism for use 524 with large congestion windows. A table indicates how much to 525 increase the congestion window by when an ACK is received. 526 For more detail see http://www.icir.org/floyd/hstcp.html 527 528config TCP_CONG_HYBLA 529 tristate "TCP-Hybla congestion control algorithm" 530 default n 531 help 532 TCP-Hybla is a sender-side only change that eliminates penalization of 533 long-RTT, large-bandwidth connections, like when satellite legs are 534 involved, especially when sharing a common bottleneck with normal 535 terrestrial connections. 536 537config TCP_CONG_VEGAS 538 tristate "TCP Vegas" 539 default n 540 help 541 TCP Vegas is a sender-side only change to TCP that anticipates 542 the onset of congestion by estimating the bandwidth. TCP Vegas 543 adjusts the sending rate by modifying the congestion 544 window. TCP Vegas should provide less packet loss, but it is 545 not as aggressive as TCP Reno. 546 547config TCP_CONG_NV 548 tristate "TCP NV" 549 default n 550 help 551 TCP NV is a follow up to TCP Vegas. It has been modified to deal with 552 10G networks, measurement noise introduced by LRO, GRO and interrupt 553 coalescence. In addition, it will decrease its cwnd multiplicatively 554 instead of linearly. 555 556 Note that in general congestion avoidance (cwnd decreased when # packets 557 queued grows) cannot coexist with congestion control (cwnd decreased only 558 when there is packet loss) due to fairness issues. One scenario when they 559 can coexist safely is when the CA flows have RTTs << CC flows RTTs. 560 561 For further details see http://www.brakmo.org/networking/tcp-nv/ 562 563config TCP_CONG_SCALABLE 564 tristate "Scalable TCP" 565 default n 566 help 567 Scalable TCP is a sender-side only change to TCP which uses a 568 MIMD congestion control algorithm which has some nice scaling 569 properties, though is known to have fairness issues. 570 See http://www.deneholme.net/tom/scalable/ 571 572config TCP_CONG_LP 573 tristate "TCP Low Priority" 574 default n 575 help 576 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 577 to utilize only the excess network bandwidth as compared to the 578 ``fair share`` of bandwidth as targeted by TCP. 579 See http://www-ece.rice.edu/networks/TCP-LP/ 580 581config TCP_CONG_VENO 582 tristate "TCP Veno" 583 default n 584 help 585 TCP Veno is a sender-side only enhancement of TCP to obtain better 586 throughput over wireless networks. TCP Veno makes use of state 587 distinguishing to circumvent the difficult judgment of the packet loss 588 type. TCP Veno cuts down less congestion window in response to random 589 loss packets. 590 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 591 592config TCP_CONG_YEAH 593 tristate "YeAH TCP" 594 select TCP_CONG_VEGAS 595 default n 596 help 597 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 598 algorithm, which uses a mixed loss/delay approach to compute the 599 congestion window. It's design goals target high efficiency, 600 internal, RTT and Reno fairness, resilience to link loss while 601 keeping network elements load as low as possible. 602 603 For further details look here: 604 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 605 606config TCP_CONG_ILLINOIS 607 tristate "TCP Illinois" 608 default n 609 help 610 TCP-Illinois is a sender-side modification of TCP Reno for 611 high speed long delay links. It uses round-trip-time to 612 adjust the alpha and beta parameters to achieve a higher average 613 throughput and maintain fairness. 614 615 For further details see: 616 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 617 618config TCP_CONG_DCTCP 619 tristate "DataCenter TCP (DCTCP)" 620 default n 621 help 622 DCTCP leverages Explicit Congestion Notification (ECN) in the network to 623 provide multi-bit feedback to the end hosts. It is designed to provide: 624 625 - High burst tolerance (incast due to partition/aggregate), 626 - Low latency (short flows, queries), 627 - High throughput (continuous data updates, large file transfers) with 628 commodity, shallow-buffered switches. 629 630 All switches in the data center network running DCTCP must support 631 ECN marking and be configured for marking when reaching defined switch 632 buffer thresholds. The default ECN marking threshold heuristic for 633 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets 634 (~100KB) at 10Gbps, but might need further careful tweaking. 635 636 For further details see: 637 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf 638 639config TCP_CONG_CDG 640 tristate "CAIA Delay-Gradient (CDG)" 641 default n 642 help 643 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies 644 the TCP sender in order to: 645 646 o Use the delay gradient as a congestion signal. 647 o Back off with an average probability that is independent of the RTT. 648 o Coexist with flows that use loss-based congestion control. 649 o Tolerate packet loss unrelated to congestion. 650 651 For further details see: 652 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using 653 delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg 654 655config TCP_CONG_BBR 656 tristate "BBR TCP" 657 default n 658 help 659 660 BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to 661 maximize network utilization and minimize queues. It builds an explicit 662 model of the the bottleneck delivery rate and path round-trip 663 propagation delay. It tolerates packet loss and delay unrelated to 664 congestion. It can operate over LAN, WAN, cellular, wifi, or cable 665 modem links. It can coexist with flows that use loss-based congestion 666 control, and can operate with shallow buffers, deep buffers, 667 bufferbloat, policers, or AQM schemes that do not provide a delay 668 signal. It requires the fq ("Fair Queue") pacing packet scheduler. 669 670choice 671 prompt "Default TCP congestion control" 672 default DEFAULT_CUBIC 673 help 674 Select the TCP congestion control that will be used by default 675 for all connections. 676 677 config DEFAULT_BIC 678 bool "Bic" if TCP_CONG_BIC=y 679 680 config DEFAULT_CUBIC 681 bool "Cubic" if TCP_CONG_CUBIC=y 682 683 config DEFAULT_HTCP 684 bool "Htcp" if TCP_CONG_HTCP=y 685 686 config DEFAULT_HYBLA 687 bool "Hybla" if TCP_CONG_HYBLA=y 688 689 config DEFAULT_VEGAS 690 bool "Vegas" if TCP_CONG_VEGAS=y 691 692 config DEFAULT_VENO 693 bool "Veno" if TCP_CONG_VENO=y 694 695 config DEFAULT_WESTWOOD 696 bool "Westwood" if TCP_CONG_WESTWOOD=y 697 698 config DEFAULT_DCTCP 699 bool "DCTCP" if TCP_CONG_DCTCP=y 700 701 config DEFAULT_CDG 702 bool "CDG" if TCP_CONG_CDG=y 703 704 config DEFAULT_BBR 705 bool "BBR" if TCP_CONG_BBR=y 706 707 config DEFAULT_RENO 708 bool "Reno" 709endchoice 710 711endif 712 713config TCP_CONG_CUBIC 714 tristate 715 depends on !TCP_CONG_ADVANCED 716 default y 717 718config DEFAULT_TCP_CONG 719 string 720 default "bic" if DEFAULT_BIC 721 default "cubic" if DEFAULT_CUBIC 722 default "htcp" if DEFAULT_HTCP 723 default "hybla" if DEFAULT_HYBLA 724 default "vegas" if DEFAULT_VEGAS 725 default "westwood" if DEFAULT_WESTWOOD 726 default "veno" if DEFAULT_VENO 727 default "reno" if DEFAULT_RENO 728 default "dctcp" if DEFAULT_DCTCP 729 default "cdg" if DEFAULT_CDG 730 default "bbr" if DEFAULT_BBR 731 default "cubic" 732 733config TCP_MD5SIG 734 bool "TCP: MD5 Signature Option support (RFC2385)" 735 select CRYPTO 736 select CRYPTO_MD5 737 help 738 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 739 Its main (only?) use is to protect BGP sessions between core routers 740 on the Internet. 741 742 If unsure, say N. 743