test.go

package main

import (
	"fmt"
	"net"
	"os"
	"syscall"

	"github.com/docker/libcontainer/netlink"
	"github.com/docker/libcontainer/system"
)

func set(f *os.File) {
	system.Setns(f.Fd(), syscall.CLONE_NEWNET)
	ifc, _ := net.InterfaceByName("mt2")
	ip, ipn, _ := net.ParseCIDR("10.222.7.101/16")
	fmt.Println("set ip", ifc, netlink.NetworkLinkAddIp(ifc, ip, ipn))
	fmt.Println("up link", ifc, netlink.NetworkLinkUp(ifc))
	defer fmt.Println("close", f.Close())
}

func main() {
	netlink.NetworkLinkAddMacVlan("em1", "mt2", "bridge")
	ifc, _ := net.InterfaceByName("mt2")
	fmt.Println("ifc in host", ifc)
	netlink.NetworkSetNsPid(ifc, 19474)

	f, _ := os.OpenFile("/proc/19474/ns/net", os.O_RDONLY, 0)
	set(f)

	ifc, _ = net.InterfaceByName("mt2")
	fmt.Println("check outside", ifc)
}