Go 对多个网络命令空间中的端口进行监听的解决方案

ip netns add ns1
ip netns add ns2

package main
import (
	"net"
	"runtime"
	"sync"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"github.com/vishvananda/netns"
)
var (
	mainNetnsHandler netns.NsHandle
	mainNetnsMutex   sync.Mutex
)
func mustInitMainNetnsHandler() {
	nh, err := netns.Get()
	if err != nil {
		panic(err)
	}
	mainNetnsHandler = nh
}
func ListenInsideNetns(ns, network, address string) (net.Listener, error) {
	if ns == "" {
		return net.Listen(network, address)
	}
	var set bool
	mainNetnsMutex.Lock()
	runtime.LockOSThread()
	defer func() {
		if set {
			err := netns.Set(mainNetnsHandler)
			if err != nil {
				logrus.WithError(err).Warn("Fail to back to main netns")
			}
		}
		runtime.UnlockOSThread()
		mainNetnsMutex.Unlock()
	}()
	nh, err := netns.GetFromName(ns)
	if err != nil {
		return nil, errors.Wrap(err, "netns.GetFromName")
	}
	defer nh.Close()
	err = netns.Set(nh)
	if err != nil {
		return nil, errors.Wrap(err, "netns.Set")
	}
	set = true
	return net.Listen(network, address)
}
func serve(listener net.Listener) error {
	for {
		conn, err := listener.Accept()
		if err != nil {
			return err
		}
		logrus.WithFields(logrus.Fields{"local": conn.LocalAddr(), "remote": conn.RemoteAddr()}).Info("New conn")
		conn.Write([]byte("hello"))
		conn.Close()
	}
}
func main() {
	mustInitMainNetnsHandler()
	wg := sync.WaitGroup{}
	wg.Add(3)
	go func() {
		defer wg.Done()
		lis, err := ListenInsideNetns("", "tcp", ":8000")
		if err != nil {
			panic(err)
		}
		logrus.WithFields(logrus.Fields{"netns": "", "addr": lis.Addr()}).Info("Listen on")
		serve(lis)
	}()
	go func() {
		defer wg.Done()
		lis, err := ListenInsideNetns("ns1", "tcp", ":8000")
		if err != nil {
			panic(err)
		}
		logrus.WithFields(logrus.Fields{"netns": "ns1", "addr": lis.Addr()}).Info("Listen on")
		serve(lis)
	}()
	go func() {
		defer wg.Done()
		lis, err := ListenInsideNetns("ns2", "tcp", ":8000")
		if err != nil {
			panic(err)
		}
		logrus.WithFields(logrus.Fields{"netns": "ns2", "addr": lis.Addr()}).Info("Listen on")
		serve(lis)
	}()
	wg.Wait()
}

type sctpWrapListener struct {
	*sctp.SCTPListener
	fd int
}
func listenSCTP(network, address string) (*sctpWrapListener, error) {
	addr, err := parseSCTPAddr(address)
	if err != nil {
		return nil, err
	}
	sctpFd := 0
	sc := sctp.SocketConfig{
		InitMsg: sctp.InitMsg{NumOstreams: sctp.SCTP_MAX_STREAM},
		Control: func(network, address string, c syscall.RawConn) error {
			return c.Control(func(fd uintptr) {
				err := syscall.SetNonblock(int(fd), true)
				if err != nil {
					syscall.Close(int(fd))
					return
				}
				sctpFd = int(fd)
			})
		},
	}
	l, err := sc.Listen(network, addr)
	if err != nil {
		return nil, err
	}
	return &sctpWrapListener{SCTPListener: l, fd: sctpFd}, nil
}

root@localhost:~# lsof -p $(pidof fake_name) | tail
fake_name 1599860 root 1203u     sock                0,8       0t0   20374830 protocol: UDP
fake_name 1599860 root 1204u     pack           20375161       0t0        ALL type=SOCK_RAW
fake_name 1599860 root 1205u     sock                0,8       0t0   20374831 protocol: SCTPv6
fake_name 1599860 root 1206u     sock                0,8       0t0   20375156 protocol: TCP
fake_name 1599860 root 1207u     sock                0,8       0t0   20375157 protocol: UDP
fake_name 1599860 root 1208u     sock                0,8       0t0   20375158 protocol: SCTPv6
fake_name 1599860 root 1209u     pack           20381769       0t0        ALL type=SOCK_RAW
fake_name 1599860 root 1210u     sock                0,8       0t0   20381764 protocol: TCP
fake_name 1599860 root 1211u     sock                0,8       0t0   20381765 protocol: UDP
fake_name 1599860 root 1212u     sock                0,8       0t0   20381766 protocol: SCTPv6
root@localhost:~# lsof -p $(pidof fake_name) | wc -l
1216

root@localhost:~# ll /proc/$(pidof fake_name)/task
total 0
dr-xr-xr-x 13 root root 0 Jul  3 14:51 ./
dr-xr-xr-x  9 root root 0 Jul  3 14:51 ../
dr-xr-xr-x  7 root root 0 Jul  3 14:51 1599860/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1599861/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1599862/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1599863/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1599864/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1599865/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1600021/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1600033/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1600056/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1600058/
dr-xr-xr-x  7 root root 0 Jul  3 14:57 1602524/
root@localhost:~# ll /proc/$(pidof fake_name)/task | wc -l
14