kernel: netfilter: add IPVS kernel module support

IPVS (IP Virtual Server) implements transport-layer load balancing inside
the Linux kernel, so called Layer-4 switching. IPVS running on a host acts
as a load balancer at the front of a cluster of real servers, it can direct
requests for TCP/UDP based services to the real servers, and makes services
of the real servers to appear as a virtual service on a single IP address.

This change adds the following kmod packages
- kmod-nf-ipvs
- kmod-nf-ipvs-ftp
- kmod-nf-ipvs-sip

Signed-off-by: Mauro Mozzarelli <mauro@ezplanet.org>
Signed-off-by: Florian Eckert <fe@dev.tdt.de>

package/kernel/linux/modules/netfilter.mk

@@ -348,6 +348,98 @@ endef
 $(eval $(call KernelPackage,ipt-ipset))
 
 
+IPVS_MODULES:= \
+	ipvs/ip_vs \
+	ipvs/ip_vs_lc \
+	ipvs/ip_vs_wlc \
+	ipvs/ip_vs_rr \
+	ipvs/ip_vs_wrr \
+	ipvs/ip_vs_lblc \
+	ipvs/ip_vs_lblcr \
+	ipvs/ip_vs_dh \
+	ipvs/ip_vs_sh \
+	ipvs/ip_vs_fo \
+	ipvs/ip_vs_ovf \
+	ipvs/ip_vs_nq \
+	ipvs/ip_vs_sed \
+	xt_ipvs
+
+define KernelPackage/nf-ipvs
+  SUBMENU:=Netfilter Extensions
+  TITLE:=IP Virtual Server modules
+  DEPENDS:=@IPV6 +kmod-lib-crc32c +kmod-ipt-conntrack +kmod-nf-conntrack
+  KCONFIG:= \
+	CONFIG_IP_VS \
+	CONFIG_IP_VS_IPV6=y \
+	CONFIG_IP_VS_DEBUG=n \
+	CONFIG_IP_VS_PROTO_TCP=y \
+	CONFIG_IP_VS_PROTO_UDP=y \
+	CONFIG_IP_VS_PROTO_AH_ESP=y \
+	CONFIG_IP_VS_PROTO_ESP=y \
+	CONFIG_IP_VS_PROTO_AH=y \
+	CONFIG_IP_VS_PROTO_SCTP=y \
+	CONFIG_IP_VS_TAB_BITS=12 \
+	CONFIG_IP_VS_RR \
+	CONFIG_IP_VS_WRR \
+	CONFIG_IP_VS_LC \
+	CONFIG_IP_VS_WLC \
+	CONFIG_IP_VS_FO \
+	CONFIG_IP_VS_OVF \
+	CONFIG_IP_VS_LBLC \
+	CONFIG_IP_VS_LBLCR \
+	CONFIG_IP_VS_DH \
+	CONFIG_IP_VS_SH \
+	CONFIG_IP_VS_SED \
+	CONFIG_IP_VS_NQ \
+	CONFIG_IP_VS_SH_TAB_BITS=8 \
+	CONFIG_IP_VS_NFCT=y \
+	CONFIG_NETFILTER_XT_MATCH_IPVS
+  FILES:=$(foreach mod,$(IPVS_MODULES),$(LINUX_DIR)/net/netfilter/$(mod).ko)
+  $(call AddDepends/ipt,+kmod-ipt-conntrack,+kmod-nf-conntrack)
+endef
+
+define KernelPackage/nf-ipvs/description
+ IPVS (IP Virtual Server) implements transport-layer load balancing inside
+ the Linux kernel so called Layer-4 switching.
+endef
+
+$(eval $(call KernelPackage,nf-ipvs))
+
+
+define KernelPackage/nf-ipvs-ftp
+  SUBMENU:=$(NF_MENU)
+  TITLE:=Virtual Server FTP protocol support
+  KCONFIG:=CONFIG_IP_VS_FTP
+  DEPENDS:=kmod-nf-ipvs +kmod-nf-nat +kmod-nf-nathelper
+  FILES:=$(LINUX_DIR)/net/netfilter/ipvs/ip_vs_ftp.ko
+endef
+
+define KernelPackage/nf-ipvs-ftp/description
+  In the virtual server via Network Address Translation,
+  the IP address and port number of real servers cannot be sent to
+  clients in ftp connections directly, so FTP protocol helper is
+  required for tracking the connection and mangling it back to that of
+  virtual service.
+endef
+
+$(eval $(call KernelPackage,nf-ipvs-ftp))
+
+
+define KernelPackage/nf-ipvs-sip
+  SUBMENU:=$(NF_MENU)
+  TITLE:=Virtual Server SIP protocol support
+  KCONFIG:=CONFIG_IP_VS_PE_SIP
+  DEPENDS:=kmod-nf-ipvs +kmod-nf-nathelper-extra
+  FILES:=$(LINUX_DIR)/net/netfilter/ipvs/ip_vs_pe_sip.ko
+endef
+
+define KernelPackage/nf-ipvs-sip/description
+  Allow persistence based on the SIP Call-ID
+endef
+
+$(eval $(call KernelPackage,nf-ipvs-sip))
+
+
 define KernelPackage/ipt-nat
   TITLE:=Basic NAT targets
   KCONFIG:=$(KCONFIG_IPT_NAT)