linux/net/Kconfig

# SPDX-License-Identifier: GPL-2.0-only
#
# Network configuration
#

menuconfig NET
	bool "Networking support"
	select NLATTR
	select GENERIC_NET_UTILS
	select BPF
	help
	  Unless you really know what you are doing, you should say Y here.
	  The reason is that some programs need kernel networking support even
	  when running on a stand-alone machine that isn't connected to any
	  other computer.

	  If you are upgrading from an older kernel, you
	  should consider updating your networking tools too because changes
	  in the kernel and the tools often go hand in hand. The tools are
	  contained in the package net-tools, the location and version number
	  of which are given in <file:Documentation/Changes>.

	  For a general introduction to Linux networking, it is highly
	  recommended to read the NET-HOWTO, available from
	  <http://www.tldp.org/docs.html#howto>.

if NET

config WANT_COMPAT_NETLINK_MESSAGES
	bool
	help
	  This option can be selected by other options that need compat
	  netlink messages.

config COMPAT_NETLINK_MESSAGES
	def_bool y
	depends on COMPAT
	depends on WEXT_CORE || WANT_COMPAT_NETLINK_MESSAGES
	help
	  This option makes it possible to send different netlink messages
	  to tasks depending on whether the task is a compat task or not. To
	  achieve this, you need to set skb_shinfo(skb)->frag_list to the
	  compat skb before sending the skb, the netlink code will sort out
	  which message to actually pass to the task.

	  Newly written code should NEVER need this option but do
	  compat-independent messages instead!

config NET_INGRESS
	bool

config NET_EGRESS
	bool

config NET_XGRESS
	select NET_INGRESS
	select NET_EGRESS
	bool

config NET_REDIRECT
	bool

config SKB_EXTENSIONS
	bool

menu "Networking options"

source "net/packet/Kconfig"
source "net/unix/Kconfig"
source "net/tls/Kconfig"
source "net/xfrm/Kconfig"
source "net/iucv/Kconfig"
source "net/smc/Kconfig"
source "net/xdp/Kconfig"

config NET_HANDSHAKE
	bool
	depends on SUNRPC || NVME_TARGET_TCP || NVME_TCP
	default y

config NET_HANDSHAKE_KUNIT_TEST
	tristate "KUnit tests for the handshake upcall mechanism" if !KUNIT_ALL_TESTS
	default KUNIT_ALL_TESTS
	depends on KUNIT
	help
	  This builds the KUnit tests for the handshake upcall mechanism.

	  KUnit tests run during boot and output the results to the debug
	  log in TAP format (https://testanything.org/). Only useful for
	  kernel devs running KUnit test harness and are not for inclusion
	  into a production build.

	  For more information on KUnit and unit tests in general, refer
	  to the KUnit documentation in Documentation/dev-tools/kunit/.

config INET
	bool "TCP/IP networking"
	help
	  These are the protocols used on the Internet and on most local
	  Ethernets. It is highly recommended to say Y here (this will enlarge
	  your kernel by about 400 KB), since some programs (e.g. the X window
	  system) use TCP/IP even if your machine is not connected to any
	  other computer. You will get the so-called loopback device which
	  allows you to ping yourself (great fun, that!).

	  For an excellent introduction to Linux networking, please read the
	  Linux Networking HOWTO, available from
	  <http://www.tldp.org/docs.html#howto>.

	  If you say Y here and also to "/proc file system support" and
	  "Sysctl support" below, you can change various aspects of the
	  behavior of the TCP/IP code by writing to the (virtual) files in
	  /proc/sys/net/ipv4/*; the options are explained in the file
	  <file:Documentation/networking/ip-sysctl.rst>.

	  Short answer: say Y.

if INET
source "net/ipv4/Kconfig"
source "net/ipv6/Kconfig"
source "net/netlabel/Kconfig"
source "net/mptcp/Kconfig"

endif # if INET

config NETWORK_SECMARK
	bool "Security Marking"
	help
	  This enables security marking of network packets, similar
	  to nfmark, but designated for security purposes.
	  If you are unsure how to answer this question, answer N.

config NET_PTP_CLASSIFY
	def_bool n

config NETWORK_PHY_TIMESTAMPING
	bool "Timestamping in PHY devices"
	select NET_PTP_CLASSIFY
	help
	  This allows timestamping of network packets by PHYs (or
	  other MII bus snooping devices) with hardware timestamping
	  capabilities. This option adds some overhead in the transmit
	  and receive paths.

	  If you are unsure how to answer this question, answer N.

menuconfig NETFILTER
	bool "Network packet filtering framework (Netfilter)"
	help
	  Netfilter is a framework for filtering and mangling network packets
	  that pass through your Linux box.

	  The most common use of packet filtering is to run your Linux box as
	  a firewall protecting a local network from the Internet. The type of
	  firewall provided by this kernel support is called a "packet
	  filter", which means that it can reject individual network packets
	  based on type, source, destination etc. The other kind of firewall,
	  a "proxy-based" one, is more secure but more intrusive and more
	  bothersome to set up; it inspects the network traffic much more
	  closely, modifies it and has knowledge about the higher level
	  protocols, which a packet filter lacks. Moreover, proxy-based
	  firewalls often require changes to the programs running on the local
	  clients. Proxy-based firewalls don't need support by the kernel, but
	  they are often combined with a packet filter, which only works if
	  you say Y here.

	  You should also say Y here if you intend to use your Linux box as
	  the gateway to the Internet for a local network of machines without
	  globally valid IP addresses. This is called "masquerading": if one
	  of the computers on your local network wants to send something to
	  the outside, your box can "masquerade" as that computer, i.e. it
	  forwards the traffic to the intended outside destination, but
	  modifies the packets to make it look like they came from the
	  firewall box itself. It works both ways: if the outside host
	  replies, the Linux box will silently forward the traffic to the
	  correct local computer. This way, the computers on your local net
	  are completely invisible to the outside world, even though they can
	  reach the outside and can receive replies. It is even possible to
	  run globally visible servers from within a masqueraded local network
	  using a mechanism called portforwarding. Masquerading is also often
	  called NAT (Network Address Translation).

	  Another use of Netfilter is in transparent proxying: if a machine on
	  the local network tries to connect to an outside host, your Linux
	  box can transparently forward the traffic to a local server,
	  typically a caching proxy server.

	  Yet another use of Netfilter is building a bridging firewall. Using
	  a bridge with Network packet filtering enabled makes iptables "see"
	  the bridged traffic. For filtering on the lower network and Ethernet
	  protocols over the bridge, use ebtables (under bridge netfilter
	  configuration).

	  Various modules exist for netfilter which replace the previous
	  masquerading (ipmasqadm), packet filtering (ipchains), transparent
	  proxying, and portforwarding mechanisms. Please see
	  <file:Documentation/Changes> under "iptables" for the location of
	  these packages.

if NETFILTER

config NETFILTER_ADVANCED
	bool "Advanced netfilter configuration"
	depends on NETFILTER
	default y
	help
	  If you say Y here you can select between all the netfilter modules.
	  If you say N the more unusual ones will not be shown and the
	  basic ones needed by most people will default to 'M'.

	  If unsure, say Y.

config BRIDGE_NETFILTER
	tristate "Bridged IP/ARP packets filtering"
	depends on BRIDGE
	depends on NETFILTER && INET
	depends on NETFILTER_ADVANCED
	select NETFILTER_FAMILY_BRIDGE
	select SKB_EXTENSIONS
	help
	  Enabling this option will let arptables resp. iptables see bridged
	  ARP resp. IP traffic. If you want a bridging firewall, you probably
	  want this option enabled.
	  Enabling or disabling this option doesn't enable or disable
	  ebtables.

	  If unsure, say N.

source "net/netfilter/Kconfig"
source "net/ipv4/netfilter/Kconfig"
source "net/ipv6/netfilter/Kconfig"
source "net/bridge/netfilter/Kconfig"

endif

source "net/dccp/Kconfig"
source "net/sctp/Kconfig"
source "net/rds/Kconfig"
source "net/tipc/Kconfig"
source "net/atm/Kconfig"
source "net/l2tp/Kconfig"
source "net/802/Kconfig"
source "net/bridge/Kconfig"
source "net/dsa/Kconfig"
source "net/8021q/Kconfig"
source "net/llc/Kconfig"
source "net/appletalk/Kconfig"
source "net/x25/Kconfig"
source "net/lapb/Kconfig"
source "net/phonet/Kconfig"
source "net/6lowpan/Kconfig"
source "net/ieee802154/Kconfig"
source "net/mac802154/Kconfig"
source "net/sched/Kconfig"
source "net/dcb/Kconfig"
source "net/dns_resolver/Kconfig"
source "net/batman-adv/Kconfig"
source "net/openvswitch/Kconfig"
source "net/vmw_vsock/Kconfig"
source "net/netlink/Kconfig"
source "net/mpls/Kconfig"
source "net/nsh/Kconfig"
source "net/hsr/Kconfig"
source "net/switchdev/Kconfig"
source "net/l3mdev/Kconfig"
source "net/qrtr/Kconfig"
source "net/ncsi/Kconfig"

config PCPU_DEV_REFCNT
	bool "Use percpu variables to maintain network device refcount"
	depends on SMP
	default y
	help
	  network device refcount are using per cpu variables if this option is set.
	  This can be forced to N to detect underflows (with a performance drop).

config MAX_SKB_FRAGS
	int "Maximum number of fragments per skb_shared_info"
	range 17 45
	default 17
	help
	  Having more fragments per skb_shared_info can help GRO efficiency.
	  This helps BIG TCP workloads, but might expose bugs in some
	  legacy drivers.
	  This also increases memory overhead of small packets,
	  and in drivers using build_skb().
	  If unsure, say 17.

config RPS
	bool
	depends on SMP && SYSFS
	default y

config RFS_ACCEL
	bool
	depends on RPS
	select CPU_RMAP
	default y

config SOCK_RX_QUEUE_MAPPING
	bool

config XPS
	bool
	depends on SMP
	select SOCK_RX_QUEUE_MAPPING
	default y

config HWBM
	bool

config CGROUP_NET_PRIO
	bool "Network priority cgroup"
	depends on CGROUPS
	select SOCK_CGROUP_DATA
	help
	  Cgroup subsystem for use in assigning processes to network priorities on
	  a per-interface basis.

config CGROUP_NET_CLASSID
	bool "Network classid cgroup"
	depends on CGROUPS
	select SOCK_CGROUP_DATA
	help
	  Cgroup subsystem for use as general purpose socket classid marker that is
	  being used in cls_cgroup and for netfilter matching.

config NET_RX_BUSY_POLL
	bool
	default y if !PREEMPT_RT || (PREEMPT_RT && !NETCONSOLE)

config BQL
	bool
	depends on SYSFS
	select DQL
	default y

config BPF_STREAM_PARSER
	bool "enable BPF STREAM_PARSER"
	depends on INET
	depends on BPF_SYSCALL
	depends on CGROUP_BPF
	select STREAM_PARSER
	select NET_SOCK_MSG
	help
	  Enabling this allows a TCP stream parser to be used with
	  BPF_MAP_TYPE_SOCKMAP.

config NET_FLOW_LIMIT
	bool
	depends on RPS
	default y
	help
	  The network stack has to drop packets when a receive processing CPU's
	  backlog reaches netdev_max_backlog. If a few out of many active flows
	  generate the vast majority of load, drop their traffic earlier to
	  maintain capacity for the other flows. This feature provides servers
	  with many clients some protection against DoS by a single (spoofed)
	  flow that greatly exceeds average workload.

menu "Network testing"

config NET_PKTGEN
	tristate "Packet Generator (USE WITH CAUTION)"
	depends on INET && PROC_FS
	help
	  This module will inject preconfigured packets, at a configurable
	  rate, out of a given interface.  It is used for network interface
	  stress testing and performance analysis.  If you don't understand
	  what was just said, you don't need it: say N.

	  Documentation on how to use the packet generator can be found
	  at <file:Documentation/networking/pktgen.rst>.

	  To compile this code as a module, choose M here: the
	  module will be called pktgen.

config NET_DROP_MONITOR
	tristate "Network packet drop alerting service"
	depends on INET && TRACEPOINTS
	help
	  This feature provides an alerting service to userspace in the
	  event that packets are discarded in the network stack.  Alerts
	  are broadcast via netlink socket to any listening user space
	  process.  If you don't need network drop alerts, or if you are ok
	  just checking the various proc files and other utilities for
	  drop statistics, say N here.

endmenu

endmenu

source "net/ax25/Kconfig"
source "net/can/Kconfig"
source "net/bluetooth/Kconfig"
source "net/rxrpc/Kconfig"
source "net/kcm/Kconfig"
source "net/strparser/Kconfig"
source "net/mctp/Kconfig"

config FIB_RULES
	bool

menuconfig WIRELESS
	bool "Wireless"
	depends on !S390
	default y

if WIRELESS

source "net/wireless/Kconfig"
source "net/mac80211/Kconfig"

endif # WIRELESS

source "net/rfkill/Kconfig"
source "net/9p/Kconfig"
source "net/caif/Kconfig"
source "net/ceph/Kconfig"
source "net/nfc/Kconfig"
source "net/psample/Kconfig"
source "net/ife/Kconfig"

config LWTUNNEL
	bool "Network light weight tunnels"
	help
	  This feature provides an infrastructure to support light weight
	  tunnels like mpls. There is no netdevice associated with a light
	  weight tunnel endpoint. Tunnel encapsulation parameters are stored
	  with light weight tunnel state associated with fib routes.

config LWTUNNEL_BPF
	bool "Execute BPF program as route nexthop action"
	depends on LWTUNNEL && INET
	default y if LWTUNNEL=y
	help
	  Allows to run BPF programs as a nexthop action following a route
	  lookup for incoming and outgoing packets.

config DST_CACHE
	bool
	default n

config GRO_CELLS
	bool
	default n

config SOCK_VALIDATE_XMIT
	bool

config NET_SELFTESTS
	def_tristate PHYLIB
	depends on PHYLIB && INET

config NET_SOCK_MSG
	bool
	default n
	help
	  The NET_SOCK_MSG provides a framework for plain sockets (e.g. TCP) or
	  ULPs (upper layer modules, e.g. TLS) to process L7 application data
	  with the help of BPF programs.

config NET_DEVLINK
	bool
	default n

config PAGE_POOL
	bool

config PAGE_POOL_STATS
	default n
	bool "Page pool stats"
	depends on PAGE_POOL
	help
	  Enable page pool statistics to track page allocation and recycling
	  in page pools. This option incurs additional CPU cost in allocation
	  and recycle paths and additional memory cost to store the statistics.
	  These statistics are only available if this option is enabled and if
	  the driver using the page pool supports exporting this data.

	  If unsure, say N.

config FAILOVER
	tristate "Generic failover module"
	help
	  The failover module provides a generic interface for paravirtual
	  drivers to register a netdev and a set of ops with a failover
	  instance. The ops are used as event handlers that get called to
	  handle netdev register/unregister/link change/name change events
	  on slave pci ethernet devices with the same mac address as the
	  failover netdev. This enables paravirtual drivers to use a
	  VF as an accelerated low latency datapath. It also allows live
	  migration of VMs with direct attached VFs by failing over to the
	  paravirtual datapath when the VF is unplugged.

config ETHTOOL_NETLINK
	bool "Netlink interface for ethtool"
	default y
	help
	  An alternative userspace interface for ethtool based on generic
	  netlink. It provides better extensibility and some new features,
	  e.g. notification messages.

config NETDEV_ADDR_LIST_TEST
	tristate "Unit tests for device address list"
	default KUNIT_ALL_TESTS
	depends on KUNIT

config NET_TEST
	tristate "KUnit tests for networking" if !KUNIT_ALL_TESTS
	depends on KUNIT
	default KUNIT_ALL_TESTS
	help
	  KUnit tests covering core networking infra, such as sk_buff.

	  If unsure, say N.

endif   # if NET