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/>. For most people, it's safe to say N. 13 14config 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 55config 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 62config 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 81config 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 93config 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 104config IP_ROUTE_CLASSID 105 bool 106 107config 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 118config 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 135config 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 150config 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 163config 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 181config 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 187config NET_IP_TUNNEL 188 tristate 189 select DST_CACHE 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 217 bool "IP: multicast routing" 218 depends on IP_MULTICAST 219 help 220 This is used if you want your machine to act as a router for IP 221 packets that have several destination addresses. It is needed on the 222 MBONE, a high bandwidth network on top of the Internet which carries 223 audio and video broadcasts. In order to do that, you would most 224 likely run the program mrouted. If you haven't heard about it, you 225 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 SYN_COOKIES 264 bool "IP: TCP syncookie support" 265 ---help--- 266 Normal TCP/IP networking is open to an attack known as "SYN 267 flooding". This denial-of-service attack prevents legitimate remote 268 users from being able to connect to your computer during an ongoing 269 attack and requires very little work from the attacker, who can 270 operate from anywhere on the Internet. 271 272 SYN cookies provide protection against this type of attack. If you 273 say Y here, the TCP/IP stack will use a cryptographic challenge 274 protocol known as "SYN cookies" to enable legitimate users to 275 continue to connect, even when your machine is under attack. There 276 is no need for the legitimate users to change their TCP/IP software; 277 SYN cookies work transparently to them. For technical information 278 about SYN cookies, check out <http://cr.yp.to/syncookies.html>. 279 280 If you are SYN flooded, the source address reported by the kernel is 281 likely to have been forged by the attacker; it is only reported as 282 an aid in tracing the packets to their actual source and should not 283 be taken as absolute truth. 284 285 SYN cookies may prevent correct error reporting on clients when the 286 server is really overloaded. If this happens frequently better turn 287 them off. 288 289 If you say Y here, you can disable SYN cookies at run time by 290 saying Y to "/proc file system support" and 291 "Sysctl support" below and executing the command 292 293 echo 0 > /proc/sys/net/ipv4/tcp_syncookies 294 295 after the /proc file system has been mounted. 296 297 If unsure, say N. 298 299config NET_IPVTI 300 tristate "Virtual (secure) IP: tunneling" 301 select INET_TUNNEL 302 select NET_IP_TUNNEL 303 depends on INET_XFRM_MODE_TUNNEL 304 ---help--- 305 Tunneling means encapsulating data of one protocol type within 306 another protocol and sending it over a channel that understands the 307 encapsulating protocol. This can be used with xfrm mode tunnel to give 308 the notion of a secure tunnel for IPSEC and then use routing protocol 309 on top. 310 311config NET_UDP_TUNNEL 312 tristate 313 select NET_IP_TUNNEL 314 default n 315 316config NET_FOU 317 tristate "IP: Foo (IP protocols) over UDP" 318 select XFRM 319 select NET_UDP_TUNNEL 320 ---help--- 321 Foo over UDP allows any IP protocol to be directly encapsulated 322 over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP 323 network mechanisms and optimizations for UDP (such as ECMP 324 and RSS) can be leveraged to provide better service. 325 326config NET_FOU_IP_TUNNELS 327 bool "IP: FOU encapsulation of IP tunnels" 328 depends on NET_IPIP || NET_IPGRE || IPV6_SIT 329 select NET_FOU 330 ---help--- 331 Allow configuration of FOU or GUE encapsulation for IP tunnels. 332 When this option is enabled IP tunnels can be configured to use 333 FOU or GUE encapsulation. 334 335config INET_AH 336 tristate "IP: AH transformation" 337 select XFRM_ALGO 338 select CRYPTO 339 select CRYPTO_HMAC 340 select CRYPTO_MD5 341 select CRYPTO_SHA1 342 ---help--- 343 Support for IPsec AH. 344 345 If unsure, say Y. 346 347config INET_ESP 348 tristate "IP: ESP transformation" 349 select XFRM_ALGO 350 select CRYPTO 351 select CRYPTO_AUTHENC 352 select CRYPTO_HMAC 353 select CRYPTO_MD5 354 select CRYPTO_CBC 355 select CRYPTO_SHA1 356 select CRYPTO_DES 357 select CRYPTO_ECHAINIV 358 ---help--- 359 Support for IPsec ESP. 360 361 If unsure, say Y. 362 363config INET_IPCOMP 364 tristate "IP: IPComp transformation" 365 select INET_XFRM_TUNNEL 366 select XFRM_IPCOMP 367 ---help--- 368 Support for IP Payload Compression Protocol (IPComp) (RFC3173), 369 typically needed for IPsec. 370 371 If unsure, say Y. 372 373config INET_XFRM_TUNNEL 374 tristate 375 select INET_TUNNEL 376 default n 377 378config INET_TUNNEL 379 tristate 380 default n 381 382config INET_XFRM_MODE_TRANSPORT 383 tristate "IP: IPsec transport mode" 384 default y 385 select XFRM 386 ---help--- 387 Support for IPsec transport mode. 388 389 If unsure, say Y. 390 391config INET_XFRM_MODE_TUNNEL 392 tristate "IP: IPsec tunnel mode" 393 default y 394 select XFRM 395 ---help--- 396 Support for IPsec tunnel mode. 397 398 If unsure, say Y. 399 400config INET_XFRM_MODE_BEET 401 tristate "IP: IPsec BEET mode" 402 default y 403 select XFRM 404 ---help--- 405 Support for IPsec BEET mode. 406 407 If unsure, say Y. 408 409config INET_DIAG 410 tristate "INET: socket monitoring interface" 411 default y 412 ---help--- 413 Support for INET (TCP, DCCP, etc) socket monitoring interface used by 414 native Linux tools such as ss. ss is included in iproute2, currently 415 downloadable at: 416 417 http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2 418 419 If unsure, say Y. 420 421config INET_TCP_DIAG 422 depends on INET_DIAG 423 def_tristate INET_DIAG 424 425config INET_UDP_DIAG 426 tristate "UDP: socket monitoring interface" 427 depends on INET_DIAG && (IPV6 || IPV6=n) 428 default n 429 ---help--- 430 Support for UDP socket monitoring interface used by the ss tool. 431 If unsure, say Y. 432 433config INET_DIAG_DESTROY 434 bool "INET: allow privileged process to administratively close sockets" 435 depends on INET_DIAG 436 default n 437 ---help--- 438 Provides a SOCK_DESTROY operation that allows privileged processes 439 (e.g., a connection manager or a network administration tool such as 440 ss) to close sockets opened by other processes. Closing a socket in 441 this way interrupts any blocking read/write/connect operations on 442 the socket and causes future socket calls to behave as if the socket 443 had been disconnected. 444 If unsure, say N. 445 446menuconfig TCP_CONG_ADVANCED 447 bool "TCP: advanced congestion control" 448 ---help--- 449 Support for selection of various TCP congestion control 450 modules. 451 452 Nearly all users can safely say no here, and a safe default 453 selection will be made (CUBIC with new Reno as a fallback). 454 455 If unsure, say N. 456 457if TCP_CONG_ADVANCED 458 459config TCP_CONG_BIC 460 tristate "Binary Increase Congestion (BIC) control" 461 default m 462 ---help--- 463 BIC-TCP is a sender-side only change that ensures a linear RTT 464 fairness under large windows while offering both scalability and 465 bounded TCP-friendliness. The protocol combines two schemes 466 called additive increase and binary search increase. When the 467 congestion window is large, additive increase with a large 468 increment ensures linear RTT fairness as well as good 469 scalability. Under small congestion windows, binary search 470 increase provides TCP friendliness. 471 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/ 472 473config TCP_CONG_CUBIC 474 tristate "CUBIC TCP" 475 default y 476 ---help--- 477 This is version 2.0 of BIC-TCP which uses a cubic growth function 478 among other techniques. 479 See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf 480 481config TCP_CONG_WESTWOOD 482 tristate "TCP Westwood+" 483 default m 484 ---help--- 485 TCP Westwood+ is a sender-side only modification of the TCP Reno 486 protocol stack that optimizes the performance of TCP congestion 487 control. It is based on end-to-end bandwidth estimation to set 488 congestion window and slow start threshold after a congestion 489 episode. Using this estimation, TCP Westwood+ adaptively sets a 490 slow start threshold and a congestion window which takes into 491 account the bandwidth used at the time congestion is experienced. 492 TCP Westwood+ significantly increases fairness wrt TCP Reno in 493 wired networks and throughput over wireless links. 494 495config TCP_CONG_HTCP 496 tristate "H-TCP" 497 default m 498 ---help--- 499 H-TCP is a send-side only modifications of the TCP Reno 500 protocol stack that optimizes the performance of TCP 501 congestion control for high speed network links. It uses a 502 modeswitch to change the alpha and beta parameters of TCP Reno 503 based on network conditions and in a way so as to be fair with 504 other Reno and H-TCP flows. 505 506config TCP_CONG_HSTCP 507 tristate "High Speed TCP" 508 default n 509 ---help--- 510 Sally Floyd's High Speed TCP (RFC 3649) congestion control. 511 A modification to TCP's congestion control mechanism for use 512 with large congestion windows. A table indicates how much to 513 increase the congestion window by when an ACK is received. 514 For more detail see http://www.icir.org/floyd/hstcp.html 515 516config TCP_CONG_HYBLA 517 tristate "TCP-Hybla congestion control algorithm" 518 default n 519 ---help--- 520 TCP-Hybla is a sender-side only change that eliminates penalization of 521 long-RTT, large-bandwidth connections, like when satellite legs are 522 involved, especially when sharing a common bottleneck with normal 523 terrestrial connections. 524 525config TCP_CONG_VEGAS 526 tristate "TCP Vegas" 527 default n 528 ---help--- 529 TCP Vegas is a sender-side only change to TCP that anticipates 530 the onset of congestion by estimating the bandwidth. TCP Vegas 531 adjusts the sending rate by modifying the congestion 532 window. TCP Vegas should provide less packet loss, but it is 533 not as aggressive as TCP Reno. 534 535config TCP_CONG_NV 536 tristate "TCP NV" 537 default n 538 ---help--- 539 TCP NV is a follow up to TCP Vegas. It has been modified to deal with 540 10G networks, measurement noise introduced by LRO, GRO and interrupt 541 coalescence. In addition, it will decrease its cwnd multiplicatively 542 instead of linearly. 543 544 Note that in general congestion avoidance (cwnd decreased when # packets 545 queued grows) cannot coexist with congestion control (cwnd decreased only 546 when there is packet loss) due to fairness issues. One scenario when they 547 can coexist safely is when the CA flows have RTTs << CC flows RTTs. 548 549 For further details see http://www.brakmo.org/networking/tcp-nv/ 550 551config TCP_CONG_SCALABLE 552 tristate "Scalable TCP" 553 default n 554 ---help--- 555 Scalable TCP is a sender-side only change to TCP which uses a 556 MIMD congestion control algorithm which has some nice scaling 557 properties, though is known to have fairness issues. 558 See http://www.deneholme.net/tom/scalable/ 559 560config TCP_CONG_LP 561 tristate "TCP Low Priority" 562 default n 563 ---help--- 564 TCP Low Priority (TCP-LP), a distributed algorithm whose goal is 565 to utilize only the excess network bandwidth as compared to the 566 ``fair share`` of bandwidth as targeted by TCP. 567 See http://www-ece.rice.edu/networks/TCP-LP/ 568 569config TCP_CONG_VENO 570 tristate "TCP Veno" 571 default n 572 ---help--- 573 TCP Veno is a sender-side only enhancement of TCP to obtain better 574 throughput over wireless networks. TCP Veno makes use of state 575 distinguishing to circumvent the difficult judgment of the packet loss 576 type. TCP Veno cuts down less congestion window in response to random 577 loss packets. 578 See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186> 579 580config TCP_CONG_YEAH 581 tristate "YeAH TCP" 582 select TCP_CONG_VEGAS 583 default n 584 ---help--- 585 YeAH-TCP is a sender-side high-speed enabled TCP congestion control 586 algorithm, which uses a mixed loss/delay approach to compute the 587 congestion window. It's design goals target high efficiency, 588 internal, RTT and Reno fairness, resilience to link loss while 589 keeping network elements load as low as possible. 590 591 For further details look here: 592 http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf 593 594config TCP_CONG_ILLINOIS 595 tristate "TCP Illinois" 596 default n 597 ---help--- 598 TCP-Illinois is a sender-side modification of TCP Reno for 599 high speed long delay links. It uses round-trip-time to 600 adjust the alpha and beta parameters to achieve a higher average 601 throughput and maintain fairness. 602 603 For further details see: 604 http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html 605 606config TCP_CONG_DCTCP 607 tristate "DataCenter TCP (DCTCP)" 608 default n 609 ---help--- 610 DCTCP leverages Explicit Congestion Notification (ECN) in the network to 611 provide multi-bit feedback to the end hosts. It is designed to provide: 612 613 - High burst tolerance (incast due to partition/aggregate), 614 - Low latency (short flows, queries), 615 - High throughput (continuous data updates, large file transfers) with 616 commodity, shallow-buffered switches. 617 618 All switches in the data center network running DCTCP must support 619 ECN marking and be configured for marking when reaching defined switch 620 buffer thresholds. The default ECN marking threshold heuristic for 621 DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets 622 (~100KB) at 10Gbps, but might need further careful tweaking. 623 624 For further details see: 625 http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf 626 627config TCP_CONG_CDG 628 tristate "CAIA Delay-Gradient (CDG)" 629 default n 630 ---help--- 631 CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies 632 the TCP sender in order to: 633 634 o Use the delay gradient as a congestion signal. 635 o Back off with an average probability that is independent of the RTT. 636 o Coexist with flows that use loss-based congestion control. 637 o Tolerate packet loss unrelated to congestion. 638 639 For further details see: 640 D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using 641 delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg 642 643config TCP_CONG_BBR 644 tristate "BBR TCP" 645 default n 646 ---help--- 647 648 BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to 649 maximize network utilization and minimize queues. It builds an explicit 650 model of the the bottleneck delivery rate and path round-trip 651 propagation delay. It tolerates packet loss and delay unrelated to 652 congestion. It can operate over LAN, WAN, cellular, wifi, or cable 653 modem links. It can coexist with flows that use loss-based congestion 654 control, and can operate with shallow buffers, deep buffers, 655 bufferbloat, policers, or AQM schemes that do not provide a delay 656 signal. It requires the fq ("Fair Queue") pacing packet scheduler. 657 658choice 659 prompt "Default TCP congestion control" 660 default DEFAULT_CUBIC 661 help 662 Select the TCP congestion control that will be used by default 663 for all connections. 664 665 config DEFAULT_BIC 666 bool "Bic" if TCP_CONG_BIC=y 667 668 config DEFAULT_CUBIC 669 bool "Cubic" if TCP_CONG_CUBIC=y 670 671 config DEFAULT_HTCP 672 bool "Htcp" if TCP_CONG_HTCP=y 673 674 config DEFAULT_HYBLA 675 bool "Hybla" if TCP_CONG_HYBLA=y 676 677 config DEFAULT_VEGAS 678 bool "Vegas" if TCP_CONG_VEGAS=y 679 680 config DEFAULT_VENO 681 bool "Veno" if TCP_CONG_VENO=y 682 683 config DEFAULT_WESTWOOD 684 bool "Westwood" if TCP_CONG_WESTWOOD=y 685 686 config DEFAULT_DCTCP 687 bool "DCTCP" if TCP_CONG_DCTCP=y 688 689 config DEFAULT_CDG 690 bool "CDG" if TCP_CONG_CDG=y 691 692 config DEFAULT_BBR 693 bool "BBR" if TCP_CONG_BBR=y 694 695 config DEFAULT_RENO 696 bool "Reno" 697endchoice 698 699endif 700 701config TCP_CONG_CUBIC 702 tristate 703 depends on !TCP_CONG_ADVANCED 704 default y 705 706config DEFAULT_TCP_CONG 707 string 708 default "bic" if DEFAULT_BIC 709 default "cubic" if DEFAULT_CUBIC 710 default "htcp" if DEFAULT_HTCP 711 default "hybla" if DEFAULT_HYBLA 712 default "vegas" if DEFAULT_VEGAS 713 default "westwood" if DEFAULT_WESTWOOD 714 default "veno" if DEFAULT_VENO 715 default "reno" if DEFAULT_RENO 716 default "dctcp" if DEFAULT_DCTCP 717 default "cdg" if DEFAULT_CDG 718 default "cubic" 719 720config TCP_MD5SIG 721 bool "TCP: MD5 Signature Option support (RFC2385)" 722 select CRYPTO 723 select CRYPTO_MD5 724 ---help--- 725 RFC2385 specifies a method of giving MD5 protection to TCP sessions. 726 Its main (only?) use is to protect BGP sessions between core routers 727 on the Internet. 728 729 If unsure, say N. 730