linux_kernel/net/Kconfig

#
# 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

menu "Networking options"

source "net/packet/Kconfig"
source "net/unix/Kconfig"
source "net/xfrm/Kconfig"
source "net/iucv/Kconfig"

config INET
	bool "TCP/IP networking"
	select CRYPTO
	select CRYPTO_AES
	---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.txt>.

	  Short answer: say Y.

if INET
source "net/ipv4/Kconfig"
source "net/ipv6/Kconfig"
source "net/netlabel/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 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_DEBUG
	bool "Network packet filtering debugging"
	depends on NETFILTER
	help
	  You can say Y here if you want to get additional messages useful in
	  debugging the netfilter code.

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
	default m
	---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/decnet/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/decnet/Kconfig"
source "net/llc/Kconfig"
source "net/ipx/Kconfig"
source "drivers/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/hsr/Kconfig"
source "net/switchdev/Kconfig"
source "net/l3mdev/Kconfig"

config RPS
	bool
	depends on SMP && SYSFS
	default y

config RFS_ACCEL
	bool
	depends on RPS
	select CPU_RMAP
	default y

config XPS
	bool
	depends on SMP
	default y

config SOCK_CGROUP_DATA
	bool
	default n

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

config BQL
	bool
	depends on SYSFS
	select DQL
	default y

config BPF_JIT
	bool "enable BPF Just In Time compiler"
	depends on HAVE_BPF_JIT
	depends on MODULES
	---help---
	  Berkeley Packet Filter filtering capabilities are normally handled
	  by an interpreter. This option allows kernel to generate a native
	  code when filter is loaded in memory. This should speedup
	  packet sniffing (libpcap/tcpdump). Note : Admin should enable
	  this feature changing /proc/sys/net/core/bpf_jit_enable

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.txt>.

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

config NET_TCPPROBE
	tristate "TCP connection probing"
	depends on INET && PROC_FS && KPROBES
	---help---
	This module allows for capturing the changes to TCP connection
	state in response to incoming packets. It is used for debugging
	TCP congestion avoidance modules. If you don't understand
	what was just said, you don't need it: say N.

	Documentation on how to use TCP connection probing can be found
	at:
	
	  http://www.linuxfoundation.org/collaborate/workgroups/networking/tcpprobe

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

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/irda/Kconfig"
source "net/bluetooth/Kconfig"
source "net/rxrpc/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/wimax/Kconfig"

source "net/rfkill/Kconfig"
source "net/9p/Kconfig"
source "net/caif/Kconfig"
source "net/ceph/Kconfig"
source "net/nfc/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.

endif   # if NET

# Used by archs to tell that they support BPF_JIT
config HAVE_BPF_JIT
	bool