1 # SPDX-License-Identifier: GPL-2.0-only 2 # 3 # IP configuration 4 # 5 config 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 <https://www.savetz.com/mbone/>. For most people, it's safe to say N. 14 15 config 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 56 config 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 63 config 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 <https://lartc.org/howto/lartc.rpdb.html> 77 78 If unsure, say N. 79 80 config 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 92 config 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"). 102 103 config IP_ROUTE_CLASSID 104 bool 105 106 config 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. 116 117 config 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. 133 134 config 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. 148 149 config 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. 161 162 config 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. 179 180 config 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. 185 186 config NET_IP_TUNNEL 187 tristate 188 select DST_CACHE 189 select GRO_CELLS 190 default n 191 192 config 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. 206 207 config 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. 215 216 config IP_MROUTE_COMMON 217 bool 218 depends on IP_MROUTE || IPV6_MROUTE 219 220 config 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. 231 232 config 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. 245 246 config 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. 258 259 config 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. 267 268 config 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 <https://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. 303 304 config 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. 316 317 config NET_UDP_TUNNEL 318 tristate 319 select NET_IP_TUNNEL 320 default n 321 322 config NET_FOU 323 tristate "IP: Foo (IP protocols) over UDP" 324 select NET_UDP_TUNNEL 325 help 326 Foo over UDP allows any IP protocol to be directly encapsulated 327 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP 328 network mechanisms and optimizations for UDP (such as ECMP 329 and RSS) can be leveraged to provide better service. 330 331 config NET_FOU_IP_TUNNELS 332 bool "IP: FOU encapsulation of IP tunnels" 333 depends on NET_IPIP || NET_IPGRE || IPV6_SIT 334 select NET_FOU 335 help 336 Allow configuration of FOU or GUE encapsulation for IP tunnels. 337 When this option is enabled IP tunnels can be configured to use 338 FOU or GUE encapsulation. 339 340 config INET_AH 341 tristate "IP: AH transformation" 342 select XFRM_AH 343 help 344 Support for IPsec AH (Authentication Header). 345 346 AH can be used with various authentication algorithms. Besides 347 enabling AH support itself, this option enables the generic 348 implementations of the algorithms that RFC 8221 lists as MUST be 349 implemented. If you need any other algorithms, you'll need to enable 350 them in the crypto API. You should also enable accelerated 351 implementations of any needed algorithms when available. 352 353 If unsure, say Y. 354 355 config INET_ESP 356 tristate "IP: ESP transformation" 357 select XFRM_ESP 358 help 359 Support for IPsec ESP (Encapsulating Security Payload). 360 361 ESP can be used with various encryption and authentication algorithms. 362 Besides enabling ESP support itself, this option enables the generic 363 implementations of the algorithms that RFC 8221 lists as MUST be 364 implemented. If you need any other algorithms, you'll need to enable 365 them in the crypto API. You should also enable accelerated 366 implementations of any needed algorithms when available. 367 368 If unsure, say Y. 369 370 config INET_ESP_OFFLOAD 371 tristate "IP: ESP transformation offload" 372 depends on INET_ESP 373 select XFRM_OFFLOAD 374 default n 375 help 376 Support for ESP transformation offload. This makes sense 377 only if this system really does IPsec and want to do it 378 with high throughput. A typical desktop system does not 379 need it, even if it does IPsec. 380 381 If unsure, say N. 382 383 config INET_ESPINTCP 384 bool "IP: ESP in TCP encapsulation (RFC 8229)" 385 depends on XFRM && INET_ESP 386 select STREAM_PARSER 387 select NET_SOCK_MSG 388 select XFRM_ESPINTCP 389 help 390 Support for RFC 8229 encapsulation of ESP and IKE over 391 TCP/IPv4 sockets. 392 393 If unsure, say N. 394 395 config INET_IPCOMP 396 tristate "IP: IPComp transformation" 397 select INET_XFRM_TUNNEL 398 select XFRM_IPCOMP 399 help 400 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 401 typically needed for IPsec. 402 403 If unsure, say Y. 404 405 config INET_TABLE_PERTURB_ORDER 406 int "INET: Source port perturbation table size (as power of 2)" if EXPERT 407 default 16 408 help 409 Source port perturbation table size (as power of 2) for 410 RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm. 411 412 The default is almost always what you want. 413 Only change this if you know what you are doing. 414 415 config INET_XFRM_TUNNEL 416 tristate 417 select INET_TUNNEL 418 default n 419 420 config INET_TUNNEL 421 tristate 422 default n 423 424 config INET_DIAG 425 tristate "INET: socket monitoring interface" 426 default y 427 help 428 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 429 native Linux tools such as ss. ss is included in iproute2, currently 430 downloadable at: 431 432 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 433 434 If unsure, say Y. 435 436 config INET_TCP_DIAG 437 depends on INET_DIAG 438 def_tristate INET_DIAG 439 440 config INET_UDP_DIAG 441 tristate "UDP: socket monitoring interface" 442 depends on INET_DIAG && (IPV6 || IPV6=n) 443 default n 444 help 445 Support for UDP socket monitoring interface used by the ss tool. 446 If unsure, say Y. 447 448 config INET_RAW_DIAG 449 tristate "RAW: socket monitoring interface" 450 depends on INET_DIAG && (IPV6 || IPV6=n) 451 default n 452 help 453 Support for RAW socket monitoring interface used by the ss tool. 454 If unsure, say Y. 455 456 config INET_DIAG_DESTROY 457 bool "INET: allow privileged process to administratively close sockets" 458 depends on INET_DIAG 459 default n 460 help 461 Provides a SOCK_DESTROY operation that allows privileged processes 462 (e.g., a connection manager or a network administration tool such as 463 ss) to close sockets opened by other processes. Closing a socket in 464 this way interrupts any blocking read/write/connect operations on 465 the socket and causes future socket calls to behave as if the socket 466 had been disconnected. 467 If unsure, say N. 468 469 menuconfig TCP_CONG_ADVANCED 470 bool "TCP: advanced congestion control" 471 help 472 Support for selection of various TCP congestion control 473 modules. 474 475 Nearly all users can safely say no here, and a safe default 476 selection will be made (CUBIC with new Reno as a fallback). 477 478 If unsure, say N. 479 480 if TCP_CONG_ADVANCED 481 482 config TCP_CONG_BIC 483 tristate "Binary Increase Congestion (BIC) control" 484 default m 485 help 486 BIC-TCP is a sender-side only change that ensures a linear RTT 487 fairness under large windows while offering both scalability and 488 bounded TCP-friendliness. The protocol combines two schemes 489 called additive increase and binary search increase. When the 490 congestion window is large, additive increase with a large 491 increment ensures linear RTT fairness as well as good 492 scalability. Under small congestion windows, binary search 493 increase provides TCP friendliness. 494 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 495 496 config TCP_CONG_CUBIC 497 tristate "CUBIC TCP" 498 default y 499 help 500 This is version 2.0 of BIC-TCP which uses a cubic growth function 501 among other techniques. 502 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 503 504 config TCP_CONG_WESTWOOD 505 tristate "TCP Westwood+" 506 default m 507 help 508 TCP Westwood+ is a sender-side only modification of the TCP Reno 509 protocol stack that optimizes the performance of TCP congestion 510 control. It is based on end-to-end bandwidth estimation to set 511 congestion window and slow start threshold after a congestion 512 episode. Using this estimation, TCP Westwood+ adaptively sets a 513 slow start threshold and a congestion window which takes into 514 account the bandwidth used at the time congestion is experienced. 515 TCP Westwood+ significantly increases fairness wrt TCP Reno in 516 wired networks and throughput over wireless links. 517 518 config TCP_CONG_HTCP 519 tristate "H-TCP" 520 default m 521 help 522 H-TCP is a send-side only modifications of the TCP Reno 523 protocol stack that optimizes the performance of TCP 524 congestion control for high speed network links. It uses a 525 modeswitch to change the alpha and beta parameters of TCP Reno 526 based on network conditions and in a way so as to be fair with 527 other Reno and H-TCP flows. 528 529 config TCP_CONG_HSTCP 530 tristate "High Speed TCP" 531 default n 532 help 533 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 534 A modification to TCP's congestion control mechanism for use 535 with large congestion windows. A table indicates how much to 536 increase the congestion window by when an ACK is received. 537 For more detail see https://www.icir.org/floyd/hstcp.html 538 539 config TCP_CONG_HYBLA 540 tristate "TCP-Hybla congestion control algorithm" 541 default n 542 help 543 TCP-Hybla is a sender-side only change that eliminates penalization of 544 long-RTT, large-bandwidth connections, like when satellite legs are 545 involved, especially when sharing a common bottleneck with normal 546 terrestrial connections. 547 548 config TCP_CONG_VEGAS 549 tristate "TCP Vegas" 550 default n 551 help 552 TCP Vegas is a sender-side only change to TCP that anticipates 553 the onset of congestion by estimating the bandwidth. TCP Vegas 554 adjusts the sending rate by modifying the congestion 555 window. TCP Vegas should provide less packet loss, but it is 556 not as aggressive as TCP Reno. 557 558 config TCP_CONG_NV 559 tristate "TCP NV" 560 default n 561 help 562 TCP NV is a follow up to TCP Vegas. It has been modified to deal with 563 10G networks, measurement noise introduced by LRO, GRO and interrupt 564 coalescence. In addition, it will decrease its cwnd multiplicatively 565 instead of linearly. 566 567 Note that in general congestion avoidance (cwnd decreased when # packets 568 queued grows) cannot coexist with congestion control (cwnd decreased only 569 when there is packet loss) due to fairness issues. One scenario when they 570 can coexist safely is when the CA flows have RTTs << CC flows RTTs. 571 572 For further details see http://www.brakmo.org/networking/tcp-nv/ 573 574 config TCP_CONG_SCALABLE 575 tristate "Scalable TCP" 576 default n 577 help 578 Scalable TCP is a sender-side only change to TCP which uses a 579 MIMD congestion control algorithm which has some nice scaling 580 properties, though is known to have fairness issues. 581 See http://www.deneholme.net/tom/scalable/ 582 583 config TCP_CONG_LP 584 tristate "TCP Low Priority" 585 default n 586 help 587 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 588 to utilize only the excess network bandwidth as compared to the 589 ``fair share`` of bandwidth as targeted by TCP. 590 See http://www-ece.rice.edu/networks/TCP-LP/ 591 592 config TCP_CONG_VENO 593 tristate "TCP Veno" 594 default n 595 help 596 TCP Veno is a sender-side only enhancement of TCP to obtain better 597 throughput over wireless networks. TCP Veno makes use of state 598 distinguishing to circumvent the difficult judgment of the packet loss 599 type. TCP Veno cuts down less congestion window in response to random 600 loss packets. 601 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 602 603 config TCP_CONG_YEAH 604 tristate "YeAH TCP" 605 select TCP_CONG_VEGAS 606 default n 607 help 608 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 609 algorithm, which uses a mixed loss/delay approach to compute the 610 congestion window. It's design goals target high efficiency, 611 internal, RTT and Reno fairness, resilience to link loss while 612 keeping network elements load as low as possible. 613 614 For further details look here: 615 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 616 617 config TCP_CONG_ILLINOIS 618 tristate "TCP Illinois" 619 default n 620 help 621 TCP-Illinois is a sender-side modification of TCP Reno for 622 high speed long delay links. It uses round-trip-time to 623 adjust the alpha and beta parameters to achieve a higher average 624 throughput and maintain fairness. 625 626 For further details see: 627 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 628 629 config TCP_CONG_DCTCP 630 tristate "DataCenter TCP (DCTCP)" 631 default n 632 help 633 DCTCP leverages Explicit Congestion Notification (ECN) in the network to 634 provide multi-bit feedback to the end hosts. It is designed to provide: 635 636 - High burst tolerance (incast due to partition/aggregate), 637 - Low latency (short flows, queries), 638 - High throughput (continuous data updates, large file transfers) with 639 commodity, shallow-buffered switches. 640 641 All switches in the data center network running DCTCP must support 642 ECN marking and be configured for marking when reaching defined switch 643 buffer thresholds. The default ECN marking threshold heuristic for 644 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets 645 (~100KB) at 10Gbps, but might need further careful tweaking. 646 647 For further details see: 648 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf 649 650 config TCP_CONG_CDG 651 tristate "CAIA Delay-Gradient (CDG)" 652 default n 653 help 654 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies 655 the TCP sender in order to: 656 657 o Use the delay gradient as a congestion signal. 658 o Back off with an average probability that is independent of the RTT. 659 o Coexist with flows that use loss-based congestion control. 660 o Tolerate packet loss unrelated to congestion. 661 662 For further details see: 663 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using 664 delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg 665 666 config TCP_CONG_BBR 667 tristate "BBR TCP" 668 default n 669 help 670 671 BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to 672 maximize network utilization and minimize queues. It builds an explicit 673 model of the bottleneck delivery rate and path round-trip propagation 674 delay. It tolerates packet loss and delay unrelated to congestion. It 675 can operate over LAN, WAN, cellular, wifi, or cable modem links. It can 676 coexist with flows that use loss-based congestion control, and can 677 operate with shallow buffers, deep buffers, bufferbloat, policers, or 678 AQM schemes that do not provide a delay signal. It requires the fq 679 ("Fair Queue") pacing packet scheduler. 680 681 choice 682 prompt "Default TCP congestion control" 683 default DEFAULT_CUBIC 684 help 685 Select the TCP congestion control that will be used by default 686 for all connections. 687 688 config DEFAULT_BIC 689 bool "Bic" if TCP_CONG_BIC=y 690 691 config DEFAULT_CUBIC 692 bool "Cubic" if TCP_CONG_CUBIC=y 693 694 config DEFAULT_HTCP 695 bool "Htcp" if TCP_CONG_HTCP=y 696 697 config DEFAULT_HYBLA 698 bool "Hybla" if TCP_CONG_HYBLA=y 699 700 config DEFAULT_VEGAS 701 bool "Vegas" if TCP_CONG_VEGAS=y 702 703 config DEFAULT_VENO 704 bool "Veno" if TCP_CONG_VENO=y 705 706 config DEFAULT_WESTWOOD 707 bool "Westwood" if TCP_CONG_WESTWOOD=y 708 709 config DEFAULT_DCTCP 710 bool "DCTCP" if TCP_CONG_DCTCP=y 711 712 config DEFAULT_CDG 713 bool "CDG" if TCP_CONG_CDG=y 714 715 config DEFAULT_BBR 716 bool "BBR" if TCP_CONG_BBR=y 717 718 config DEFAULT_RENO 719 bool "Reno" 720 endchoice 721 722 endif 723 724 config TCP_CONG_CUBIC 725 tristate 726 depends on !TCP_CONG_ADVANCED 727 default y 728 729 config DEFAULT_TCP_CONG 730 string 731 default "bic" if DEFAULT_BIC 732 default "cubic" if DEFAULT_CUBIC 733 default "htcp" if DEFAULT_HTCP 734 default "hybla" if DEFAULT_HYBLA 735 default "vegas" if DEFAULT_VEGAS 736 default "westwood" if DEFAULT_WESTWOOD 737 default "veno" if DEFAULT_VENO 738 default "reno" if DEFAULT_RENO 739 default "dctcp" if DEFAULT_DCTCP 740 default "cdg" if DEFAULT_CDG 741 default "bbr" if DEFAULT_BBR 742 default "cubic" 743 744 config TCP_MD5SIG 745 bool "TCP: MD5 Signature Option support (RFC2385)" 746 select CRYPTO 747 select CRYPTO_MD5 748 help 749 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 750 Its main (only?) use is to protect BGP sessions between core routers 751 on the Internet. 752 753 If unsure, say N. 754