ok

.gitignore

@@ -0,0 +1 @@
+/etherip-client

cmd/root.go

@@ -0,0 +1,44 @@
+/*
+Copyright © 2026 Masato Kikuchi <m-kikuchi@neody.ad.jp>
+*/
+package cmd
+
+import (
+	"net"
+	"os"
+
+	"git.neody.ad.jp/tuna2134/etherip-client/utils"
+	"github.com/spf13/cobra"
+)
+
+var devName string
+var localIP net.IP
+var remoteIP net.IP
+var linkName string
+
+var rootCmd = &cobra.Command{
+	Use:   "etherip-client",
+	Short: "Ethernet over IPv6(RFC3378)カーネルのクライアント",
+	RunE: runE,
+}
+
+func runE(cmd *cobra.Command, args []string) error {
+	err := utils.AddDev(devName, localIP, remoteIP, linkName)
+	return err
+}
+
+func Execute() {
+	err := rootCmd.Execute()
+	if err != nil {
+		os.Exit(1)
+	}
+}
+
+func init() {
+	rootCmd.Flags().StringVarP(&devName, "devname", "d", "eip0", "作成するNICの名")
+	rootCmd.Flags().IPVarP(&localIP, "local", "l", nil, "自分の終端アドレス")
+	rootCmd.Flags().IPVarP(&remoteIP, "remote", "r", nil, "相手の終端アドレス")
+	rootCmd.Flags().StringVarP(&linkName, "link", "L", "", "アンダーレイのNIC名")
+}
+
+

go.mod

@@ -0,0 +1,15 @@
+module git.neody.ad.jp/tuna2134/etherip-client
+
+go 1.26.4
+
+require (
+	github.com/vishvananda/netlink v1.3.1
+	golang.org/x/sys v0.46.0
+)
+
+require (
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/spf13/cobra v1.10.2 // indirect
+	github.com/spf13/pflag v1.0.9 // indirect
+	github.com/vishvananda/netns v0.0.5 // indirect
+)

go.sum

@@ -0,0 +1,18 @@
+github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/spf13/cobra v1.10.2 h1:DMTTonx5m65Ic0GOoRY2c16WCbHxOOw6xxezuLaBpcU=
+github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiTUUS4=
+github.com/spf13/pflag v1.0.9 h1:9exaQaMOCwffKiiiYk6/BndUBv+iRViNW+4lEMi0PvY=
+github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW6bV0=
+github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
+github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
+github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
+go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
+golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

main.go

@@ -0,0 +1,10 @@
+/*
+Copyright © 2026 Masato Kikuchi <m-kikuchi@neody.ad.jp>
+*/
+package main
+
+import "git.neody.ad.jp/tuna2134/etherip-client/cmd"
+
+func main() {
+	cmd.Execute()
+}

test.sh

@@ -0,0 +1 @@
+sudo ./etherip-client -d eip0 -l 2402:2f60:500:beef:be24:11ff:fe12:d655 -r 2401:5e40:1:462:6709:e050:dcc5:d592 -L ens18

utils/addDev.go

@@ -0,0 +1,67 @@
+/*
+Copyright © 2026 Masato Kikuchi <m-kikuchi@neody.ad.jp>
+*/
+
+package utils
+
+import (
+	"encoding/binary"
+	"net"
+
+	"github.com/vishvananda/netlink"
+	"github.com/vishvananda/netlink/nl"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	IFLA_ETHERIP6_UNSPEC = iota
+	IFLA_ETHERIP6_LOCAL
+	IFLA_ETHERIP6_REMOTE
+	IFLA_ETHERIP6_LINK
+	IFLA_ETHERIP6_HOP_LIMIT
+)
+
+func u32(v uint32) []byte {
+	b := make([]byte, 4)
+	binary.NativeEndian.PutUint32(b, v)
+	return b
+}
+
+func AddDev(DevName string, local net.IP, remote net.IP, linkName string) error {
+	req := nl.NewNetlinkRequest(
+		unix.RTM_NEWLINK,
+		unix.NLM_F_REQUEST|unix.NLM_F_CREATE|unix.NLM_F_EXCL|unix.NLM_F_ACK,
+	)
+
+	msg := nl.NewIfInfomsg(unix.AF_UNSPEC)
+	req.AddData(msg)
+
+	req.AddData(nl.NewRtAttr(unix.IFLA_IFNAME, []byte(DevName)))
+
+	linkInfo := nl.NewRtAttr(unix.IFLA_LINKINFO, nil)
+	linkInfo.AddRtAttr(nl.IFLA_INFO_KIND, nl.ZeroTerminated("etherip6"))
+
+	infoData := nl.NewRtAttr(nl.IFLA_INFO_DATA, nil)
+	infoData.AddRtAttr(IFLA_ETHERIP6_LOCAL, local.To16())
+	infoData.AddRtAttr(IFLA_ETHERIP6_REMOTE, remote.To16())
+
+	if linkName != "" {
+		link, err := netlink.LinkByName(linkName)
+		if err != nil {
+			return err
+		}
+		infoData.AddRtAttr(IFLA_ETHERIP6_LINK, u32(uint32(link.Attrs().Index)))
+	}
+
+	infoData.AddRtAttr(IFLA_ETHERIP6_HOP_LIMIT, []byte{255})
+
+	linkInfo.AddRtAttr(nl.IFLA_INFO_DATA, infoData.Serialize())
+	req.AddData(linkInfo)
+
+	_, err := req.Execute(unix.NETLINK_ROUTE, 0)
+
+	if err != nil {
+		return err
+	}
+	return nil
+}