Go 对多个网络命令空间中的端口进行监听的解决方案

目录

• 新方案
• 使用 Go 进行实现
实现对 TCP 的监听
UDP/SCTP 的监听
实际应用的数据参考

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

• Go语言实现的简单网络端口扫描方法