openwrt对于kernel module的处理分两类：随内核主线而来的kernel module 和 其他作为独立project的kernel module。而这两种，openwrt将采用相同的模版进行处理。
对于随内核主线一起提供的kernel module，the makefiles are located in package/kernel/modules/*.mk and they appear under the section "Kernel modules"。举例：package/kernel/modules/netfilter.mk，全文如下：
#
# Copyright (C) 2006-2008 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
NF_MENU:=Netfilter Extensions
NF_KMOD:=1
include $(INCLUDE_DIR)/netfilter.mk
define KernelPackage/ipt-core
SUBMENU:=$(NF_MENU) //The sub menu under which this package will be seen
TITLE:=Netfilter core //The name of the module as seen via menuconfig
KCONFIG:=$(KCONFIG_IPT_CORE) //Kernel configuration option dependency. For external modules, remove it.
FILES:=$(foreach mod,$(IPT_CORE-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX)) //Files you want to inlude to this kernel module package, separate with spaces.
AUTOLOAD:=$(call AutoLoad,40,$(notdir $(IPT_CORE-m))) //Modules that will be loaded automatically on boot, the order you write them is the order they would be loaded.
endef
define KernelPackage/ipt-core/description
Netfilter core kernel modules
Includes:
- comment (2.6)
- limit
- LOG
- mac
- multiport
- REJECT
- TCPMSS
endef
$(eval $(call KernelPackage,ipt-core))
define KernelPackage/ipt/Depends
SUBMENU:=$(NF_MENU)
DEPENDS:= kmod-ipt-core $(1)
endef
define KernelPackage/ipt-conntrack
$(call KernelPackage/ipt/Depends,)
TITLE:=Basic connection tracking modules
KCONFIG:=$(KCONFIG_IPT_CONNTRACK)
FILES:=$(foreach mod,$(IPT_CONNTRACK-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,41,$(notdir $(IPT_CONNTRACK-m)))
endef
define KernelPackage/ipt-conntrack/description
Netfilter (IPv4) kernel modules for connection tracking
Includes:
- conntrack
- defrag (2.6)
- iptables_raw
- NOTRACK
- state
endef
$(eval $(call KernelPackage,ipt-conntrack))
define KernelPackage/ipt-conntrack-extra
$(call KernelPackage/ipt/Depends,+kmod-ipt-conntrack)
TITLE:=Extra connection tracking modules
KCONFIG:=$(KCONFIG_IPT_CONNTRACK_EXTRA)
FILES:=$(foreach mod,$(IPT_CONNTRACK_EXTRA-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,42,$(notdir $(IPT_CONNTRACK_EXTRA-m)))
endef
define KernelPackage/ipt-conntrack-extra/description
Netfilter (IPv4) extra kernel modules for connection tracking
Includes:
- connbytes
- connmark/CONNMARK
- conntrack
- helper
- recent
endef
$(eval $(call KernelPackage,ipt-conntrack-extra))
define KernelPackage/ipt-filter
$(call KernelPackage/ipt/Depends,+LINUX_2_6:kmod-textsearch)
TITLE:=Modules for packet content inspection
KCONFIG:=$(KCONFIG_IPT_FILTER)
FILES:=$(foreach mod,$(IPT_FILTER-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_FILTER-m)))
endef
define KernelPackage/ipt-filter/description
Netfilter (IPv4) kernel modules for packet content inspection
Includes:
- layer7
- string
endef
$(eval $(call KernelPackage,ipt-filter))
define KernelPackage/ipt-ipopt
$(call KernelPackage/ipt/Depends,)
TITLE:=Modules for matching/changing IP packet options
KCONFIG:=$(KCONFIG_IPT_IPOPT)
FILES:=$(foreach mod,$(IPT_IPOPT-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_IPOPT-m)))
endef
define KernelPackage/ipt-ipopt/description
Netfilter (IPv4) modules for matching/changing IP packet options
Includes:
- CLASSIFY
- dscp/DSCP
- ecn/ECN
- hl/HL (2.6.30 and later)
- length
- mark/MARK
- statistic (2.6)
- tcpmss
- time
- tos/TOS (prior to 2.6.25)
- ttl/TTL (prior to 2.6.30)
- unclean
endef
$(eval $(call KernelPackage,ipt-ipopt))
define KernelPackage/ipt-ipsec
$(call KernelPackage/ipt/Depends,)
TITLE:=Modules for matching IPSec packets
KCONFIG:=$(KCONFIG_IPT_IPSEC)
FILES:=$(foreach mod,$(IPT_IPSEC-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_IPSEC-m)))
endef
define KernelPackage/ipt-ipsec/description
Netfilter (IPv4) modules for matching IPSec packets
Includes:
- ah
- esp
- policy (2.6)
endef
$(eval $(call KernelPackage,ipt-ipsec))
define KernelPackage/ipt-nat
$(call KernelPackage/ipt/Depends,+kmod-ipt-conntrack)
TITLE:=Basic NAT targets
KCONFIG:=$(KCONFIG_IPT_NAT)
FILES:=$(foreach mod,$(IPT_NAT-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,42,$(notdir $(IPT_NAT-m)))
endef
define KernelPackage/ipt-nat/description
Netfilter (IPv4) kernel modules for basic NAT targets
Includes:
- MASQUERADE
endef
$(eval $(call KernelPackage,ipt-nat))
define KernelPackage/ipt-nat-extra
$(call KernelPackage/ipt/Depends,+kmod-ipt-nat)
TITLE:=Extra NAT targets
KCONFIG:=$(KCONFIG_IPT_NAT_EXTRA)
FILES:=$(foreach mod,$(IPT_NAT_EXTRA-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,43,$(notdir $(IPT_NAT_EXTRA-m)))
endef
define KernelPackage/ipt-nat-extra/description
Netfilter (IPv4) kernel modules for extra NAT targets
Includes:
- MIRROR (2.4)
- NETMAP
- REDIRECT
endef
$(eval $(call KernelPackage,ipt-nat-extra))
define KernelPackage/ipt-nathelper
$(call KernelPackage/ipt/Depends,+kmod-ipt-nat)
TITLE:=Basic Conntrack and NAT helpers
KCONFIG:=$(KCONFIG_IPT_NATHELPER)
FILES:=$(foreach mod,$(IPT_NATHELPER-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_NATHELPER-m)))
endef
define KernelPackage/ipt-nathelper/description
Default Netfilter (IPv4) Conntrack and NAT helpers
Includes:
- ftp
- irc
- tftp
endef
$(eval $(call KernelPackage,ipt-nathelper))
define KernelPackage/ipt-nathelper-extra
$(call KernelPackage/ipt/Depends,+kmod-ipt-nat +LINUX_2_6:kmod-textsearch)
TITLE:=Extra Conntrack and NAT helpers
KCONFIG:=$(KCONFIG_IPT_NATHELPER_EXTRA)
FILES:=$(foreach mod,$(IPT_NATHELPER_EXTRA-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_NATHELPER_EXTRA-m)))
endef
define KernelPackage/ipt-nathelper-extra/description
Extra Netfilter (IPv4) Conntrack and NAT helpers
Includes:
- amanda
- h323
- mms
- pptp (2.6)
- proto_gre (2.6)
- rtsp
- sip (2.6)
- snmp_basic
endef
$(eval $(call KernelPackage,ipt-nathelper-extra))
define KernelPackage/ipt-imq
$(call KernelPackage/ipt/Depends,)
TITLE:=Intermediate Queueing support
KCONFIG:=
CONFIG_IMQ
CONFIG_IMQ_BEHAVIOR_BA=y
CONFIG_IMQ_NUM_DEVS=2
CONFIG_NETFILTER_XT_TARGET_IMQ
FILES:=
$(LINUX_DIR)/drivers/net/imq.$(LINUX_KMOD_SUFFIX)
$(foreach mod,$(IPT_IMQ-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir
imq
$(IPT_IMQ-m)
))
endef
define KernelPackage/ipt-imq/description
Kernel support for Intermediate Queueing devices
endef
$(eval $(call KernelPackage,ipt-imq))
define KernelPackage/ipt-queue
$(call KernelPackage/ipt/Depends,)
TITLE:=Module for user-space packet queueing
KCONFIG:=$(KCONFIG_IPT_QUEUE)
FILES:=$(foreach mod,$(IPT_QUEUE-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_QUEUE-m)))
endef
define KernelPackage/ipt-queue/description
Netfilter (IPv4) module for user-space packet queueing
Includes:
- QUEUE
endef
$(eval $(call KernelPackage,ipt-queue))
define KernelPackage/ipt-ulog
$(call KernelPackage/ipt/Depends,)
TITLE:=Module for user-space packet logging
KCONFIG:=$(KCONFIG_IPT_ULOG)
FILES:=$(foreach mod,$(IPT_ULOG-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_ULOG-m)))
endef
define KernelPackage/ipt-ulog/description
Netfilter (IPv4) module for user-space packet logging
Includes:
- ULOG
endef
$(eval $(call KernelPackage,ipt-ulog))
define KernelPackage/ipt-iprange
$(call KernelPackage/ipt/Depends,)
TITLE:=Module for matching ip ranges
KCONFIG:=$(KCONFIG_IPT_IPRANGE)
FILES:=$(foreach mod,$(IPT_IPRANGE-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_IPRANGE-m)))
endef
define KernelPackage/ipt-iprange/description
Netfilter (IPv4) module for matching ip ranges
Includes:
- iprange
endef
$(eval $(call KernelPackage,ipt-iprange))
define KernelPackage/ipt-extra
$(call KernelPackage/ipt/Depends,)
TITLE:=Extra modules
KCONFIG:=$(KCONFIG_IPT_EXTRA)
FILES:=$(foreach mod,$(IPT_EXTRA-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,45,$(notdir $(IPT_EXTRA-m)))
endef
define KernelPackage/ipt-extra/description
Other Netfilter (IPv4) kernel modules
Includes:
- condition (2.4 only)
- owner
- physdev (if bridge support was enabled in kernel)
- pkttype
- quota
endef
$(eval $(call KernelPackage,ipt-extra))
define KernelPackage/ip6tables
SUBMENU:=$(NF_MENU)
TITLE:=IPv6 modules
DEPENDS:=+kmod-ipv6
KCONFIG:=$(KCONFIG_IPT_IPV6)
FILES:=$(foreach mod,$(IPT_IPV6-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(IPT_IPV6-m)))
endef
define KernelPackage/ip6tables/description
Netfilter IPv6 firewalling support
endef
$(eval $(call KernelPackage,ip6tables))
define KernelPackage/arptables
SUBMENU:=$(NF_MENU)
TITLE:=ARP firewalling modules
FILES:=$(LINUX_DIR)/net/ipv4/netfilter/arp*.$(LINUX_KMOD_SUFFIX)
KCONFIG:=CONFIG_IP_NF_ARPTABLES
CONFIG_IP_NF_ARPFILTER
CONFIG_IP_NF_ARP_MANGLE
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(patsubst %.$(LINUX_KMOD_SUFFIX),%,$(wildcard $(LINUX_DIR)/net/ipv4/netfilter/arp*.$(LINUX_KMOD_SUFFIX)))))
endef
define KernelPackage/arptables/description
Kernel modules for ARP firewalling
endef
$(eval $(call KernelPackage,arptables))
define KernelPackage/ebtables
SUBMENU:=$(NF_MENU)
TITLE:=Bridge firewalling modules
DEPENDS:=@LINUX_2_6
FILES:=$(foreach mod,$(EBTABLES-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
KCONFIG:=CONFIG_BRIDGE_NETFILTER=y
$(KCONFIG_EBTABLES)
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(EBTABLES-m)))
endef
define KernelPackage/ebtables/description
ebtables is a general, extensible frame/packet identification
framework. It provides you to do Ethernet
filtering/NAT/brouting on the Ethernet bridge.
endef
$(eval $(call KernelPackage,ebtables))
define KernelPackage/ebtables/Depends
SUBMENU:=$(NF_MENU)
DEPENDS:=kmod-ebtables $(1)
endef
define KernelPackage/ebtables-ipv4
$(call KernelPackage/ebtables/Depends,)
TITLE:=ebtables: IPv4 support
FILES:=$(foreach mod,$(EBTABLES_IP4-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
KCONFIG:=$(KCONFIG_EBTABLES_IP4)
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(EBTABLES_IP4-m)))
endef
define KernelPackage/ebtables-ipv4/description
This option adds the IPv4 support to ebtables, which allows basic
IPv4 header field filtering, ARP filtering as well as SNAT, DNAT targets.
endef
$(eval $(call KernelPackage,ebtables-ipv4))
define KernelPackage/ebtables-ipv6
$(call KernelPackage/ebtables/Depends,)
TITLE:=ebtables: IPv6 support
FILES:=$(foreach mod,$(EBTABLES_IP6-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
KCONFIG:=$(KCONFIG_EBTABLES_IP6)
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(EBTABLES_IP6-m)))
endef
define KernelPackage/ebtables-ipv6/description
This option adds the IPv6 support to ebtables, which allows basic
IPv6 header field filtering and target support.
endef
$(eval $(call KernelPackage,ebtables-ipv6))
define KernelPackage/ebtables-watchers
$(call KernelPackage/ebtables/Depends,)
TITLE:=ebtables: watchers support
FILES:=$(foreach mod,$(EBTABLES_WATCHERS-m),$(LINUX_DIR)/net/$(mod).$(LINUX_KMOD_SUFFIX))
KCONFIG:=$(KCONFIG_EBTABLES_WATCHERS)
AUTOLOAD:=$(call AutoLoad,49,$(notdir $(EBTABLES_WATCHERS-m)))
endef
define KernelPackage/ebtables-watchers/description
This option adds the log watchers, that you can use in any rule
in any ebtables table.
endef
$(eval $(call KernelPackage,ebtables-watchers))
define KernelPackage/nfnetlink
SUBMENU:=$(NF_MENU)
TITLE:=Netlink-based userspace interface
DEPENDS:=@LINUX_2_6 +kmod-ipt-core
FILES:=$(LINUX_DIR)/net/netfilter/nfnetlink.$(LINUX_KMOD_SUFFIX)
KCONFIG:=CONFIG_NETFILTER_NETLINK
AUTOLOAD:=$(call AutoLoad,48,nfnetlink)
endef
define KernelPackage/nfnetlink/description
Kernel modules support for a netlink-based userspace interface
endef
$(eval $(call KernelPackage,nfnetlink))
define KernelPackage/nfnetlink/Depends
SUBMENU:=$(NF_MENU)
DEPENDS:=@LINUX_2_6 +kmod-nfnetlink $(1)
endef
define KernelPackage/nfnetlink-log
$(call KernelPackage/nfnetlink/Depends,)
TITLE:=Netfilter LOG over NFNETLINK interface
FILES:=$(LINUX_DIR)/net/netfilter/nfnetlink_log.$(LINUX_KMOD_SUFFIX)
KCONFIG:=CONFIG_NETFILTER_NETLINK_LOG
AUTOLOAD:=$(call AutoLoad,48,nfnetlink_log)
endef
define KernelPackage/nfnetlink-log/description
Kernel modules support for logging packets via NFNETLINK
endef
$(eval $(call KernelPackage,nfnetlink-log))
define KernelPackage/nfnetlink-queue
$(call KernelPackage/nfnetlink/Depends,)
TITLE:=Netfilter QUEUE over NFNETLINK interface
FILES:=$(LINUX_DIR)/net/netfilter/nfnetlink_queue.$(LINUX_KMOD_SUFFIX)
KCONFIG:=CONFIG_NETFILTER_NETLINK_QUEUE
AUTOLOAD:=$(call AutoLoad,48,nfnetlink_queue)
endef
define KernelPackage/nfnetlink-queue/description
Kernel modules support for queueing packets via NFNETLINK
endef
$(eval $(call KernelPackage,nfnetlink-queue))
define KernelPackage/nf-conntrack-netlink
$(call KernelPackage/nfnetlink/Depends,+kmod-ipt-conntrack)
TITLE:=Connection tracking netlink interface
FILES:=$(LINUX_DIR)/net/netfilter/nf_conntrack_netlink.$(LINUX_KMOD_SUFFIX)
KCONFIG:=CONFIG_NF_CT_NETLINK
AUTOLOAD:=$(call AutoLoad,49,nf_conntrack_netlink)
endef
define KernelPackage/nf-conntrack-netlink/description
Kernel modules support for a netlink-based connection tracking
userspace interface
endef
$(eval $(call KernelPackage,nf-conntrack-netlink))
而对于外部独立的kernel module，you can add them to the build system just like if they were software packages by defining a KernelPackage section in the package makefile.