network: add virtual tunnel interface (VTI) support

This adds support for configuring VTI interfaces within /etc/config/network.
VTI interfaces are used to create IPsec tunnel interfaces. These interfaces
may be used for routing and other purposes.

Example config:
config interface 'vti1'
	option proto 'vti'
	option mtu '1500'
	option tunlink 'wan'
	option peeraddr '192.168.5.16'
	option zone 'VPN'
	option ikey 2
	option okey 2

config interface 'vti1_static'
	option proto 'static'
	option ifname '@vti1'
	option ipaddr '192.168.7.2/24'

The options ikey and okey correspond to the fwmark value of a ipsec policy.
The may be null if you do not want fwmarks.
Also peeraddr may be 0.0.0 if you want all ESP packets go through the
interface.
Example strongswan config:
conn vti
	left=%any
	leftcert=peer2.test.der
	leftid=@peer2.test
	right=192.168.5.16
	rightid=@peer3.test
	leftsubnet=0.0.0.0/0
	rightsubnet=0.0.0.0/0
	mark=2
	auto=route

Signed-off-by: André Valentin <avalentin@marcant.net>

SVN-Revision: 48274

package/network/config/vti/Makefile

@@ -0,0 +1,65 @@
+#
+# Copyright (C) 2014 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=vti
+PKG_VERSION:=1
+PKG_RELEASE:=1
+PKG_LICENSE:=GPL-2.0
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/vti/Default
+  SECTION:=net
+  CATEGORY:=Network
+  MAINTAINER:=Andre Valentin <avalentin@marcant.net>
+endef
+
+define Package/vti
+$(call Package/vti/Default)
+  TITLE:=Virtual IPsec Tunnel Interface config support
+endef
+
+define Package/vti/description
+ Virtual IPsec Tunnel Interface config support (IPv4 and IPv6) in /etc/config/network.
+endef
+
+define Package/vtiv4
+$(call Package/vti/Default)
+  TITLE:=Virtual IPsec Tunnel Interface (IPv4) config support
+  DEPENDS:=@(PACKAGE_vti) +kmod-ip_vti
+endef
+
+define Package/vtiv4/description
+ Virtual IPsec Tunnel Interface config support (IPv4) in /etc/config/network.
+endef
+
+define Package/vtiv6
+$(call Package/vti/Default)
+  TITLE:=Virtual IPsec Tunnel Interface (IPv6) config support
+  DEPENDS:=@(PACKAGE_vti) @IPV6 +kmod-ip6_vti
+endef
+
+define Package/vtiv6/description
+ Virtual IPsec Tunnel Interface config support (IPv6) in /etc/config/network.
+endef
+
+define Build/Compile
+endef
+
+define Build/Configure
+endef
+
+define Package/vti/install
+	$(INSTALL_DIR) $(1)/lib/netifd/proto
+	$(INSTALL_BIN) ./files/vti.sh $(1)/lib/netifd/proto/vti.sh
+endef
+
+$(eval $(call BuildPackage,vti))
+$(eval $(call BuildPackage,vtiv4))
+$(eval $(call BuildPackage,vtiv6))

package/network/config/vti/files/vti.sh

@@ -0,0 +1,151 @@
+#!/bin/sh
+
+[ -n "$INCLUDE_ONLY" ] || {
+	. /lib/functions.sh
+	. /lib/functions/network.sh
+	. ../netifd-proto.sh
+	init_proto "$@"
+}
+
+vti_generic_setup() {
+	local cfg="$1"
+	local mode="$2"
+	local local="$3"
+	local remote="$4"
+	local link="$5"
+	local mtu zone ikey
+	json_get_vars mtu zone ikey okey
+
+	[ -z "$zone" ] && zone="wan"
+
+	proto_init_update "$link" 1
+
+	proto_add_tunnel
+	json_add_string mode "$mode"
+	json_add_int mtu "${mtu:-1280}"
+	json_add_string local "$local"
+	json_add_string remote "$remote"
+	[ -n "$tunlink" ] && json_add_string link "$tunlink"
+	json_add_string info "${ikey:-0},${okey:-0}"
+	proto_close_tunnel
+
+	proto_add_data
+	[ -n "$zone" ] && json_add_string zone "$zone"
+	proto_close_data
+
+	proto_send_update "$cfg"
+}
+
+vti_setup() {
+	local cfg="$1"
+	local mode="$2"
+
+	local ipaddr peeraddr
+	json_get_vars df ipaddr peeraddr tunlink
+
+	[ -z "$peeraddr" ] && {
+		proto_notify_error "$cfg" "MISSING_ADDRESS"
+		proto_block_restart "$cfg"
+		exit
+	}
+
+	( proto_add_host_dependency "$cfg" "$peeraddr" "$tunlink" )
+
+	[ -z "$ipaddr" ] && {
+		local wanif="$tunlink"
+		if [ -z $wanif ] && ! network_find_wan wanif; then
+			proto_notify_error "$cfg" "NO_WAN_LINK"
+			exit
+		fi
+
+		if ! network_get_ipaddr ipaddr "$wanif"; then
+			proto_notify_error "$cfg" "NO_WAN_LINK"
+			exit
+		fi
+	}
+
+	vti_generic_setup $cfg $mode $ipaddr $peeraddr "vti-$cfg"
+}
+
+proto_vti_setup() {
+	local cfg="$1"
+
+	vti_setup $cfg "vtiip"
+}
+
+vti6_setup() {
+	local cfg="$1"
+	local mode="$2"
+
+	local ip6addr peer6addr weakif
+	json_get_vars ip6addr peer6addr tunlink weakif
+
+	[ -z "$peer6addr" ] && {
+		proto_notify_error "$cfg" "MISSING_ADDRESS"
+		proto_block_restart "$cfg"
+		exit
+	}
+
+	( proto_add_host_dependency "$cfg" "$peer6addr" "$tunlink" )
+
+	[ -z "$ip6addr" ] && {
+		local wanif="$tunlink"
+		if [ -z $wanif ] && ! network_find_wan6 wanif; then
+			proto_notify_error "$cfg" "NO_WAN_LINK"
+			exit
+		fi
+
+		if ! network_get_ipaddr6 ip6addr "$wanif"; then
+			[ -z "$weakif" ] && weakif="lan"
+			if ! network_get_ipaddr6 ip6addr "$weakif"; then
+				proto_notify_error "$cfg" "NO_WAN_LINK"
+				exit
+			fi
+		fi
+	}
+
+	vti_generic_setup $cfg $mode $ip6addr $peer6addr "vti6-$cfg"
+}
+
+proto_vti6_setup() {
+	local cfg="$1"
+
+	vti6_setup $cfg "vtiip6"
+}
+
+proto_vti_teardown() {
+	local cfg="$1"
+}
+
+proto_vti6_teardown() {
+	local cfg="$1"
+}
+
+vti_generic_init_config() {
+	no_device=1
+	available=1
+
+	proto_config_add_int "mtu"
+	proto_config_add_string "tunlink"
+	proto_config_add_string "zone"
+	proto_config_add_int "ikey"
+	proto_config_add_int "okey"
+}
+
+proto_vti_init_config() {
+	vti_generic_init_config
+	proto_config_add_string "ipaddr"
+	proto_config_add_string "peeraddr"
+}
+
+proto_vti6_init_config() {
+	vti_generic_init_config
+	proto_config_add_string "ip6addr"
+	proto_config_add_string "peer6addr"
+	proto_config_add_string "weakif"
+}
+
+[ -n "$INCLUDE_ONLY" ] || {
+	[ -f /lib/modules/$(uname -r)/ip_vti.ko ] && add_protocol vti
+	[ -f /lib/modules/$(uname -r)/ip6_vti.ko ] && add_protocol vti6
+}