v4.19.13 snapshot.
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
new file mode 100644
index 0000000..32cae39
--- /dev/null
+++ b/net/ipv4/Kconfig
@@ -0,0 +1,755 @@
+#
+# IP configuration
+#
+config IP_MULTICAST
+ bool "IP: multicasting"
+ help
+ This is code for addressing several networked computers at once,
+ enlarging your kernel by about 2 KB. You need multicasting if you
+ intend to participate in the MBONE, a high bandwidth network on top
+ of the Internet which carries audio and video broadcasts. More
+ information about the MBONE is on the WWW at
+ <http://www.savetz.com/mbone/>. For most people, it's safe to say N.
+
+config IP_ADVANCED_ROUTER
+ bool "IP: advanced router"
+ ---help---
+ If you intend to run your Linux box mostly as a router, i.e. as a
+ computer that forwards and redistributes network packets, say Y; you
+ will then be presented with several options that allow more precise
+ control about the routing process.
+
+ The answer to this question won't directly affect the kernel:
+ answering N will just cause the configurator to skip all the
+ questions about advanced routing.
+
+ Note that your box can only act as a router if you enable IP
+ forwarding in your kernel; you can do that by saying Y to "/proc
+ file system support" and "Sysctl support" below and executing the
+ line
+
+ echo "1" > /proc/sys/net/ipv4/ip_forward
+
+ at boot time after the /proc file system has been mounted.
+
+ If you turn on IP forwarding, you should consider the rp_filter, which
+ automatically rejects incoming packets if the routing table entry
+ for their source address doesn't match the network interface they're
+ arriving on. This has security advantages because it prevents the
+ so-called IP spoofing, however it can pose problems if you use
+ asymmetric routing (packets from you to a host take a different path
+ than packets from that host to you) or if you operate a non-routing
+ host which has several IP addresses on different interfaces. To turn
+ rp_filter on use:
+
+ echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
+ or
+ echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
+
+ Note that some distributions enable it in startup scripts.
+ For details about rp_filter strict and loose mode read
+ <file:Documentation/networking/ip-sysctl.txt>.
+
+ If unsure, say N here.
+
+config IP_FIB_TRIE_STATS
+ bool "FIB TRIE statistics"
+ depends on IP_ADVANCED_ROUTER
+ ---help---
+ Keep track of statistics on structure of FIB TRIE table.
+ Useful for testing and measuring TRIE performance.
+
+config IP_MULTIPLE_TABLES
+ bool "IP: policy routing"
+ depends on IP_ADVANCED_ROUTER
+ select FIB_RULES
+ ---help---
+ Normally, a router decides what to do with a received packet based
+ solely on the packet's final destination address. If you say Y here,
+ the Linux router will also be able to take the packet's source
+ address into account. Furthermore, the TOS (Type-Of-Service) field
+ of the packet can be used for routing decisions as well.
+
+ If you need more information, see the Linux Advanced
+ Routing and Traffic Control documentation at
+ <http://lartc.org/howto/lartc.rpdb.html>
+
+ If unsure, say N.
+
+config IP_ROUTE_MULTIPATH
+ bool "IP: equal cost multipath"
+ depends on IP_ADVANCED_ROUTER
+ help
+ Normally, the routing tables specify a single action to be taken in
+ a deterministic manner for a given packet. If you say Y here
+ however, it becomes possible to attach several actions to a packet
+ pattern, in effect specifying several alternative paths to travel
+ for those packets. The router considers all these paths to be of
+ equal "cost" and chooses one of them in a non-deterministic fashion
+ if a matching packet arrives.
+
+config IP_ROUTE_VERBOSE
+ bool "IP: verbose route monitoring"
+ depends on IP_ADVANCED_ROUTER
+ help
+ If you say Y here, which is recommended, then the kernel will print
+ verbose messages regarding the routing, for example warnings about
+ received packets which look strange and could be evidence of an
+ attack or a misconfigured system somewhere. The information is
+ handled by the klogd daemon which is responsible for kernel messages
+ ("man klogd").
+
+config IP_ROUTE_CLASSID
+ bool
+
+config IP_PNP
+ bool "IP: kernel level autoconfiguration"
+ help
+ This enables automatic configuration of IP addresses of devices and
+ of the routing table during kernel boot, based on either information
+ supplied on the kernel command line or by BOOTP or RARP protocols.
+ You need to say Y only for diskless machines requiring network
+ access to boot (in which case you want to say Y to "Root file system
+ on NFS" as well), because all other machines configure the network
+ in their startup scripts.
+
+config IP_PNP_DHCP
+ bool "IP: DHCP support"
+ depends on IP_PNP
+ ---help---
+ If you want your Linux box to mount its whole root file system (the
+ one containing the directory /) from some other computer over the
+ net via NFS and you want the IP address of your computer to be
+ discovered automatically at boot time using the DHCP protocol (a
+ special protocol designed for doing this job), say Y here. In case
+ the boot ROM of your network card was designed for booting Linux and
+ does DHCP itself, providing all necessary information on the kernel
+ command line, you can say N here.
+
+ If unsure, say Y. Note that if you want to use DHCP, a DHCP server
+ must be operating on your network. Read
+ <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
+
+config IP_PNP_BOOTP
+ bool "IP: BOOTP support"
+ depends on IP_PNP
+ ---help---
+ If you want your Linux box to mount its whole root file system (the
+ one containing the directory /) from some other computer over the
+ net via NFS and you want the IP address of your computer to be
+ discovered automatically at boot time using the BOOTP protocol (a
+ special protocol designed for doing this job), say Y here. In case
+ the boot ROM of your network card was designed for booting Linux and
+ does BOOTP itself, providing all necessary information on the kernel
+ command line, you can say N here. If unsure, say Y. Note that if you
+ want to use BOOTP, a BOOTP server must be operating on your network.
+ Read <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
+
+config IP_PNP_RARP
+ bool "IP: RARP support"
+ depends on IP_PNP
+ help
+ If you want your Linux box to mount its whole root file system (the
+ one containing the directory /) from some other computer over the
+ net via NFS and you want the IP address of your computer to be
+ discovered automatically at boot time using the RARP protocol (an
+ older protocol which is being obsoleted by BOOTP and DHCP), say Y
+ here. Note that if you want to use RARP, a RARP server must be
+ operating on your network. Read
+ <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
+
+config NET_IPIP
+ tristate "IP: tunneling"
+ select INET_TUNNEL
+ select NET_IP_TUNNEL
+ ---help---
+ Tunneling means encapsulating data of one protocol type within
+ another protocol and sending it over a channel that understands the
+ encapsulating protocol. This particular tunneling driver implements
+ encapsulation of IP within IP, which sounds kind of pointless, but
+ can be useful if you want to make your (or some other) machine
+ appear on a different network than it physically is, or to use
+ mobile-IP facilities (allowing laptops to seamlessly move between
+ networks without changing their IP addresses).
+
+ Saying Y to this option will produce two modules ( = code which can
+ be inserted in and removed from the running kernel whenever you
+ want). Most people won't need this and can say N.
+
+config NET_IPGRE_DEMUX
+ tristate "IP: GRE demultiplexer"
+ help
+ This is helper module to demultiplex GRE packets on GRE version field criteria.
+ Required by ip_gre and pptp modules.
+
+config NET_IP_TUNNEL
+ tristate
+ select DST_CACHE
+ select GRO_CELLS
+ default n
+
+config NET_IPGRE
+ tristate "IP: GRE tunnels over IP"
+ depends on (IPV6 || IPV6=n) && NET_IPGRE_DEMUX
+ select NET_IP_TUNNEL
+ help
+ Tunneling means encapsulating data of one protocol type within
+ another protocol and sending it over a channel that understands the
+ encapsulating protocol. This particular tunneling driver implements
+ GRE (Generic Routing Encapsulation) and at this time allows
+ encapsulating of IPv4 or IPv6 over existing IPv4 infrastructure.
+ This driver is useful if the other endpoint is a Cisco router: Cisco
+ likes GRE much better than the other Linux tunneling driver ("IP
+ tunneling" above). In addition, GRE allows multicast redistribution
+ through the tunnel.
+
+config NET_IPGRE_BROADCAST
+ bool "IP: broadcast GRE over IP"
+ depends on IP_MULTICAST && NET_IPGRE
+ help
+ One application of GRE/IP is to construct a broadcast WAN (Wide Area
+ Network), which looks like a normal Ethernet LAN (Local Area
+ Network), but can be distributed all over the Internet. If you want
+ to do that, say Y here and to "IP multicast routing" below.
+
+config IP_MROUTE_COMMON
+ bool
+ depends on IP_MROUTE || IPV6_MROUTE
+
+config IP_MROUTE
+ bool "IP: multicast routing"
+ depends on IP_MULTICAST
+ select IP_MROUTE_COMMON
+ help
+ This is used if you want your machine to act as a router for IP
+ packets that have several destination addresses. It is needed on the
+ MBONE, a high bandwidth network on top of the Internet which carries
+ audio and video broadcasts. In order to do that, you would most
+ likely run the program mrouted. If you haven't heard about it, you
+ don't need it.
+
+config IP_MROUTE_MULTIPLE_TABLES
+ bool "IP: multicast policy routing"
+ depends on IP_MROUTE && IP_ADVANCED_ROUTER
+ select FIB_RULES
+ help
+ Normally, a multicast router runs a userspace daemon and decides
+ what to do with a multicast packet based on the source and
+ destination addresses. If you say Y here, the multicast router
+ will also be able to take interfaces and packet marks into
+ account and run multiple instances of userspace daemons
+ simultaneously, each one handling a single table.
+
+ If unsure, say N.
+
+config IP_PIMSM_V1
+ bool "IP: PIM-SM version 1 support"
+ depends on IP_MROUTE
+ help
+ Kernel side support for Sparse Mode PIM (Protocol Independent
+ Multicast) version 1. This multicast routing protocol is used widely
+ because Cisco supports it. You need special software to use it
+ (pimd-v1). Please see <http://netweb.usc.edu/pim/> for more
+ information about PIM.
+
+ Say Y if you want to use PIM-SM v1. Note that you can say N here if
+ you just want to use Dense Mode PIM.
+
+config IP_PIMSM_V2
+ bool "IP: PIM-SM version 2 support"
+ depends on IP_MROUTE
+ help
+ Kernel side support for Sparse Mode PIM version 2. In order to use
+ this, you need an experimental routing daemon supporting it (pimd or
+ gated-5). This routing protocol is not used widely, so say N unless
+ you want to play with it.
+
+config SYN_COOKIES
+ bool "IP: TCP syncookie support"
+ ---help---
+ Normal TCP/IP networking is open to an attack known as "SYN
+ flooding". This denial-of-service attack prevents legitimate remote
+ users from being able to connect to your computer during an ongoing
+ attack and requires very little work from the attacker, who can
+ operate from anywhere on the Internet.
+
+ SYN cookies provide protection against this type of attack. If you
+ say Y here, the TCP/IP stack will use a cryptographic challenge
+ protocol known as "SYN cookies" to enable legitimate users to
+ continue to connect, even when your machine is under attack. There
+ is no need for the legitimate users to change their TCP/IP software;
+ SYN cookies work transparently to them. For technical information
+ about SYN cookies, check out <http://cr.yp.to/syncookies.html>.
+
+ If you are SYN flooded, the source address reported by the kernel is
+ likely to have been forged by the attacker; it is only reported as
+ an aid in tracing the packets to their actual source and should not
+ be taken as absolute truth.
+
+ SYN cookies may prevent correct error reporting on clients when the
+ server is really overloaded. If this happens frequently better turn
+ them off.
+
+ If you say Y here, you can disable SYN cookies at run time by
+ saying Y to "/proc file system support" and
+ "Sysctl support" below and executing the command
+
+ echo 0 > /proc/sys/net/ipv4/tcp_syncookies
+
+ after the /proc file system has been mounted.
+
+ If unsure, say N.
+
+config NET_IPVTI
+ tristate "Virtual (secure) IP: tunneling"
+ select INET_TUNNEL
+ select NET_IP_TUNNEL
+ depends on INET_XFRM_MODE_TUNNEL
+ ---help---
+ Tunneling means encapsulating data of one protocol type within
+ another protocol and sending it over a channel that understands the
+ encapsulating protocol. This can be used with xfrm mode tunnel to give
+ the notion of a secure tunnel for IPSEC and then use routing protocol
+ on top.
+
+config NET_UDP_TUNNEL
+ tristate
+ select NET_IP_TUNNEL
+ default n
+
+config NET_FOU
+ tristate "IP: Foo (IP protocols) over UDP"
+ select XFRM
+ select NET_UDP_TUNNEL
+ ---help---
+ Foo over UDP allows any IP protocol to be directly encapsulated
+ over UDP include tunnels (IPIP, GRE, SIT). By encapsulating in UDP
+ network mechanisms and optimizations for UDP (such as ECMP
+ and RSS) can be leveraged to provide better service.
+
+config NET_FOU_IP_TUNNELS
+ bool "IP: FOU encapsulation of IP tunnels"
+ depends on NET_IPIP || NET_IPGRE || IPV6_SIT
+ select NET_FOU
+ ---help---
+ Allow configuration of FOU or GUE encapsulation for IP tunnels.
+ When this option is enabled IP tunnels can be configured to use
+ FOU or GUE encapsulation.
+
+config INET_AH
+ tristate "IP: AH transformation"
+ select XFRM_ALGO
+ select CRYPTO
+ select CRYPTO_HMAC
+ select CRYPTO_MD5
+ select CRYPTO_SHA1
+ ---help---
+ Support for IPsec AH.
+
+ If unsure, say Y.
+
+config INET_ESP
+ tristate "IP: ESP transformation"
+ select XFRM_ALGO
+ select CRYPTO
+ select CRYPTO_AUTHENC
+ select CRYPTO_HMAC
+ select CRYPTO_MD5
+ select CRYPTO_CBC
+ select CRYPTO_SHA1
+ select CRYPTO_DES
+ select CRYPTO_ECHAINIV
+ ---help---
+ Support for IPsec ESP.
+
+ If unsure, say Y.
+
+config INET_ESP_OFFLOAD
+ tristate "IP: ESP transformation offload"
+ depends on INET_ESP
+ select XFRM_OFFLOAD
+ default n
+ ---help---
+ Support for ESP transformation offload. This makes sense
+ only if this system really does IPsec and want to do it
+ with high throughput. A typical desktop system does not
+ need it, even if it does IPsec.
+
+ If unsure, say N.
+
+config INET_IPCOMP
+ tristate "IP: IPComp transformation"
+ select INET_XFRM_TUNNEL
+ select XFRM_IPCOMP
+ ---help---
+ Support for IP Payload Compression Protocol (IPComp) (RFC3173),
+ typically needed for IPsec.
+
+ If unsure, say Y.
+
+config INET_XFRM_TUNNEL
+ tristate
+ select INET_TUNNEL
+ default n
+
+config INET_TUNNEL
+ tristate
+ default n
+
+config INET_XFRM_MODE_TRANSPORT
+ tristate "IP: IPsec transport mode"
+ default y
+ select XFRM
+ ---help---
+ Support for IPsec transport mode.
+
+ If unsure, say Y.
+
+config INET_XFRM_MODE_TUNNEL
+ tristate "IP: IPsec tunnel mode"
+ default y
+ select XFRM
+ ---help---
+ Support for IPsec tunnel mode.
+
+ If unsure, say Y.
+
+config INET_XFRM_MODE_BEET
+ tristate "IP: IPsec BEET mode"
+ default y
+ select XFRM
+ ---help---
+ Support for IPsec BEET mode.
+
+ If unsure, say Y.
+
+config INET_DIAG
+ tristate "INET: socket monitoring interface"
+ default y
+ ---help---
+ Support for INET (TCP, DCCP, etc) socket monitoring interface used by
+ native Linux tools such as ss. ss is included in iproute2, currently
+ downloadable at:
+
+ http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2
+
+ If unsure, say Y.
+
+config INET_TCP_DIAG
+ depends on INET_DIAG
+ def_tristate INET_DIAG
+
+config INET_UDP_DIAG
+ tristate "UDP: socket monitoring interface"
+ depends on INET_DIAG && (IPV6 || IPV6=n)
+ default n
+ ---help---
+ Support for UDP socket monitoring interface used by the ss tool.
+ If unsure, say Y.
+
+config INET_RAW_DIAG
+ tristate "RAW: socket monitoring interface"
+ depends on INET_DIAG && (IPV6 || IPV6=n)
+ default n
+ ---help---
+ Support for RAW socket monitoring interface used by the ss tool.
+ If unsure, say Y.
+
+config INET_DIAG_DESTROY
+ bool "INET: allow privileged process to administratively close sockets"
+ depends on INET_DIAG
+ default n
+ ---help---
+ Provides a SOCK_DESTROY operation that allows privileged processes
+ (e.g., a connection manager or a network administration tool such as
+ ss) to close sockets opened by other processes. Closing a socket in
+ this way interrupts any blocking read/write/connect operations on
+ the socket and causes future socket calls to behave as if the socket
+ had been disconnected.
+ If unsure, say N.
+
+menuconfig TCP_CONG_ADVANCED
+ bool "TCP: advanced congestion control"
+ ---help---
+ Support for selection of various TCP congestion control
+ modules.
+
+ Nearly all users can safely say no here, and a safe default
+ selection will be made (CUBIC with new Reno as a fallback).
+
+ If unsure, say N.
+
+if TCP_CONG_ADVANCED
+
+config TCP_CONG_BIC
+ tristate "Binary Increase Congestion (BIC) control"
+ default m
+ ---help---
+ BIC-TCP is a sender-side only change that ensures a linear RTT
+ fairness under large windows while offering both scalability and
+ bounded TCP-friendliness. The protocol combines two schemes
+ called additive increase and binary search increase. When the
+ congestion window is large, additive increase with a large
+ increment ensures linear RTT fairness as well as good
+ scalability. Under small congestion windows, binary search
+ increase provides TCP friendliness.
+ See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
+
+config TCP_CONG_CUBIC
+ tristate "CUBIC TCP"
+ default y
+ ---help---
+ This is version 2.0 of BIC-TCP which uses a cubic growth function
+ among other techniques.
+ See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf
+
+config TCP_CONG_WESTWOOD
+ tristate "TCP Westwood+"
+ default m
+ ---help---
+ TCP Westwood+ is a sender-side only modification of the TCP Reno
+ protocol stack that optimizes the performance of TCP congestion
+ control. It is based on end-to-end bandwidth estimation to set
+ congestion window and slow start threshold after a congestion
+ episode. Using this estimation, TCP Westwood+ adaptively sets a
+ slow start threshold and a congestion window which takes into
+ account the bandwidth used at the time congestion is experienced.
+ TCP Westwood+ significantly increases fairness wrt TCP Reno in
+ wired networks and throughput over wireless links.
+
+config TCP_CONG_HTCP
+ tristate "H-TCP"
+ default m
+ ---help---
+ H-TCP is a send-side only modifications of the TCP Reno
+ protocol stack that optimizes the performance of TCP
+ congestion control for high speed network links. It uses a
+ modeswitch to change the alpha and beta parameters of TCP Reno
+ based on network conditions and in a way so as to be fair with
+ other Reno and H-TCP flows.
+
+config TCP_CONG_HSTCP
+ tristate "High Speed TCP"
+ default n
+ ---help---
+ Sally Floyd's High Speed TCP (RFC 3649) congestion control.
+ A modification to TCP's congestion control mechanism for use
+ with large congestion windows. A table indicates how much to
+ increase the congestion window by when an ACK is received.
+ For more detail see http://www.icir.org/floyd/hstcp.html
+
+config TCP_CONG_HYBLA
+ tristate "TCP-Hybla congestion control algorithm"
+ default n
+ ---help---
+ TCP-Hybla is a sender-side only change that eliminates penalization of
+ long-RTT, large-bandwidth connections, like when satellite legs are
+ involved, especially when sharing a common bottleneck with normal
+ terrestrial connections.
+
+config TCP_CONG_VEGAS
+ tristate "TCP Vegas"
+ default n
+ ---help---
+ TCP Vegas is a sender-side only change to TCP that anticipates
+ the onset of congestion by estimating the bandwidth. TCP Vegas
+ adjusts the sending rate by modifying the congestion
+ window. TCP Vegas should provide less packet loss, but it is
+ not as aggressive as TCP Reno.
+
+config TCP_CONG_NV
+ tristate "TCP NV"
+ default n
+ ---help---
+ TCP NV is a follow up to TCP Vegas. It has been modified to deal with
+ 10G networks, measurement noise introduced by LRO, GRO and interrupt
+ coalescence. In addition, it will decrease its cwnd multiplicatively
+ instead of linearly.
+
+ Note that in general congestion avoidance (cwnd decreased when # packets
+ queued grows) cannot coexist with congestion control (cwnd decreased only
+ when there is packet loss) due to fairness issues. One scenario when they
+ can coexist safely is when the CA flows have RTTs << CC flows RTTs.
+
+ For further details see http://www.brakmo.org/networking/tcp-nv/
+
+config TCP_CONG_SCALABLE
+ tristate "Scalable TCP"
+ default n
+ ---help---
+ Scalable TCP is a sender-side only change to TCP which uses a
+ MIMD congestion control algorithm which has some nice scaling
+ properties, though is known to have fairness issues.
+ See http://www.deneholme.net/tom/scalable/
+
+config TCP_CONG_LP
+ tristate "TCP Low Priority"
+ default n
+ ---help---
+ TCP Low Priority (TCP-LP), a distributed algorithm whose goal is
+ to utilize only the excess network bandwidth as compared to the
+ ``fair share`` of bandwidth as targeted by TCP.
+ See http://www-ece.rice.edu/networks/TCP-LP/
+
+config TCP_CONG_VENO
+ tristate "TCP Veno"
+ default n
+ ---help---
+ TCP Veno is a sender-side only enhancement of TCP to obtain better
+ throughput over wireless networks. TCP Veno makes use of state
+ distinguishing to circumvent the difficult judgment of the packet loss
+ type. TCP Veno cuts down less congestion window in response to random
+ loss packets.
+ See <http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1177186>
+
+config TCP_CONG_YEAH
+ tristate "YeAH TCP"
+ select TCP_CONG_VEGAS
+ default n
+ ---help---
+ YeAH-TCP is a sender-side high-speed enabled TCP congestion control
+ algorithm, which uses a mixed loss/delay approach to compute the
+ congestion window. It's design goals target high efficiency,
+ internal, RTT and Reno fairness, resilience to link loss while
+ keeping network elements load as low as possible.
+
+ For further details look here:
+ http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
+
+config TCP_CONG_ILLINOIS
+ tristate "TCP Illinois"
+ default n
+ ---help---
+ TCP-Illinois is a sender-side modification of TCP Reno for
+ high speed long delay links. It uses round-trip-time to
+ adjust the alpha and beta parameters to achieve a higher average
+ throughput and maintain fairness.
+
+ For further details see:
+ http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
+
+config TCP_CONG_DCTCP
+ tristate "DataCenter TCP (DCTCP)"
+ default n
+ ---help---
+ DCTCP leverages Explicit Congestion Notification (ECN) in the network to
+ provide multi-bit feedback to the end hosts. It is designed to provide:
+
+ - High burst tolerance (incast due to partition/aggregate),
+ - Low latency (short flows, queries),
+ - High throughput (continuous data updates, large file transfers) with
+ commodity, shallow-buffered switches.
+
+ All switches in the data center network running DCTCP must support
+ ECN marking and be configured for marking when reaching defined switch
+ buffer thresholds. The default ECN marking threshold heuristic for
+ DCTCP on switches is 20 packets (30KB) at 1Gbps, and 65 packets
+ (~100KB) at 10Gbps, but might need further careful tweaking.
+
+ For further details see:
+ http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
+
+config TCP_CONG_CDG
+ tristate "CAIA Delay-Gradient (CDG)"
+ default n
+ ---help---
+ CAIA Delay-Gradient (CDG) is a TCP congestion control that modifies
+ the TCP sender in order to:
+
+ o Use the delay gradient as a congestion signal.
+ o Back off with an average probability that is independent of the RTT.
+ o Coexist with flows that use loss-based congestion control.
+ o Tolerate packet loss unrelated to congestion.
+
+ For further details see:
+ D.A. Hayes and G. Armitage. "Revisiting TCP congestion control using
+ delay gradients." In Networking 2011. Preprint: http://goo.gl/No3vdg
+
+config TCP_CONG_BBR
+ tristate "BBR TCP"
+ default n
+ ---help---
+
+ BBR (Bottleneck Bandwidth and RTT) TCP congestion control aims to
+ maximize network utilization and minimize queues. It builds an explicit
+ model of the the bottleneck delivery rate and path round-trip
+ propagation delay. It tolerates packet loss and delay unrelated to
+ congestion. It can operate over LAN, WAN, cellular, wifi, or cable
+ modem links. It can coexist with flows that use loss-based congestion
+ control, and can operate with shallow buffers, deep buffers,
+ bufferbloat, policers, or AQM schemes that do not provide a delay
+ signal. It requires the fq ("Fair Queue") pacing packet scheduler.
+
+choice
+ prompt "Default TCP congestion control"
+ default DEFAULT_CUBIC
+ help
+ Select the TCP congestion control that will be used by default
+ for all connections.
+
+ config DEFAULT_BIC
+ bool "Bic" if TCP_CONG_BIC=y
+
+ config DEFAULT_CUBIC
+ bool "Cubic" if TCP_CONG_CUBIC=y
+
+ config DEFAULT_HTCP
+ bool "Htcp" if TCP_CONG_HTCP=y
+
+ config DEFAULT_HYBLA
+ bool "Hybla" if TCP_CONG_HYBLA=y
+
+ config DEFAULT_VEGAS
+ bool "Vegas" if TCP_CONG_VEGAS=y
+
+ config DEFAULT_VENO
+ bool "Veno" if TCP_CONG_VENO=y
+
+ config DEFAULT_WESTWOOD
+ bool "Westwood" if TCP_CONG_WESTWOOD=y
+
+ config DEFAULT_DCTCP
+ bool "DCTCP" if TCP_CONG_DCTCP=y
+
+ config DEFAULT_CDG
+ bool "CDG" if TCP_CONG_CDG=y
+
+ config DEFAULT_BBR
+ bool "BBR" if TCP_CONG_BBR=y
+
+ config DEFAULT_RENO
+ bool "Reno"
+endchoice
+
+endif
+
+config TCP_CONG_CUBIC
+ tristate
+ depends on !TCP_CONG_ADVANCED
+ default y
+
+config DEFAULT_TCP_CONG
+ string
+ default "bic" if DEFAULT_BIC
+ default "cubic" if DEFAULT_CUBIC
+ default "htcp" if DEFAULT_HTCP
+ default "hybla" if DEFAULT_HYBLA
+ default "vegas" if DEFAULT_VEGAS
+ default "westwood" if DEFAULT_WESTWOOD
+ default "veno" if DEFAULT_VENO
+ default "reno" if DEFAULT_RENO
+ default "dctcp" if DEFAULT_DCTCP
+ default "cdg" if DEFAULT_CDG
+ default "bbr" if DEFAULT_BBR
+ default "cubic"
+
+config TCP_MD5SIG
+ bool "TCP: MD5 Signature Option support (RFC2385)"
+ select CRYPTO
+ select CRYPTO_MD5
+ ---help---
+ RFC2385 specifies a method of giving MD5 protection to TCP sessions.
+ Its main (only?) use is to protect BGP sessions between core routers
+ on the Internet.
+
+ If unsure, say N.