Golang netns.NsHandle函数代码示例

func checkSandbox(t *testing.T, info libnetwork.EndpointInfo) {
	origns, err := netns.Get()
	if err != nil {
		t.Fatalf("Could not get the current netns: %v", err)
	}
	defer origns.Close()

	key := info.Sandbox().Key()
	f, err := os.OpenFile(key, os.O_RDONLY, 0)
	if err != nil {
		t.Fatalf("Failed to open network namespace path %q: %v", key, err)
	}
	defer f.Close()

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	nsFD := f.Fd()
	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		t.Fatalf("Setting to the namespace pointed to by the sandbox %s failed: %v", key, err)
	}
	defer netns.Set(origns)

	_, err = netlink.LinkByName("eth0")
	if err != nil {
		t.Fatalf("Could not find the interface eth0 inside the sandbox: %v", err)
	}

	_, err = netlink.LinkByName("eth1")
	if err != nil {
		t.Fatalf("Could not find the interface eth1 inside the sandbox: %v", err)
	}
}

func nsInvoke(path string, prefunc func(nsFD int) error, postfunc func(callerFD int) error) error {
	defer InitOSContext()()

	f, err := os.OpenFile(path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", path, err)
	}
	defer f.Close()

	nsFD := f.Fd()

	// Invoked before the namespace switch happens but after the namespace file
	// handle is obtained.
	if err := prefunc(int(nsFD)); err != nil {
		return fmt.Errorf("failed in prefunc: %v", err)
	}

	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer ns.SetNamespace()

	// Invoked after the namespace switch.
	return postfunc(ns.ParseHandlerInt())
}

func setupNetNs(nsPath string) (*os.Process, error) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return nil, err
	}
	defer origns.Close()

	f, err := os.OpenFile(nsPath, os.O_RDONLY, 0)
	if err != nil {
		return nil, fmt.Errorf("failed to get network namespace %q: %v", nsPath, err)
	}
	defer f.Close()

	nsFD := f.Fd()
	if err := netns.Set(netns.NsHandle(nsFD)); err != nil {
		return nil, fmt.Errorf("failed to set network namespace %q: %v", nsPath, err)
	}
	defer netns.Set(origns)

	cmd := exec.Command("/bin/sh", "-c", "while true; do sleep 1; done")
	if err := cmd.Start(); err != nil {
		return nil, fmt.Errorf("failed to start netns process: %v", err)
	}

	return cmd.Process, nil
}

func verifySandbox(t *testing.T, s Sandbox, ifaceSuffixes []string) {
	_, ok := s.(*networkNamespace)
	if !ok {
		t.Fatalf("The sandox interface returned is not of type networkNamespace")
	}

	origns, err := netns.Get()
	if err != nil {
		t.Fatalf("Could not get the current netns: %v", err)
	}
	defer origns.Close()

	f, err := os.OpenFile(s.Key(), os.O_RDONLY, 0)
	if err != nil {
		t.Fatalf("Failed top open network namespace path %q: %v", s.Key(), err)
	}
	defer f.Close()

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	nsFD := f.Fd()
	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		t.Fatalf("Setting to the namespace pointed to by the sandbox %s failed: %v", s.Key(), err)
	}
	defer netns.Set(origns)

	for _, suffix := range ifaceSuffixes {
		_, err = netlink.LinkByName(sboxIfaceName + suffix)
		if err != nil {
			t.Fatalf("Could not find the interface %s inside the sandbox: %v",
				sboxIfaceName+suffix, err)
		}
	}
}

func nsInvoke(path string, prefunc func(nsFD int) error, postfunc func(callerFD int) error) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return err
	}
	defer origns.Close()

	f, err := os.OpenFile(path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", path, err)
	}
	defer f.Close()

	nsFD := f.Fd()

	// Invoked before the namespace switch happens but after the namespace file
	// handle is obtained.
	if err := prefunc(int(nsFD)); err != nil {
		return fmt.Errorf("failed in prefunc: %v", err)
	}

	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer netns.Set(origns)

	// Invoked after the namespace switch.
	return postfunc(int(origns))
}

func nsInvoke(path string, inNsfunc func(callerFD int) error) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return err
	}
	defer origns.Close()

	f, err := os.OpenFile(path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", path, err)
	}
	defer f.Close()

	nsFD := f.Fd()

	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer netns.Set(origns)

	// Invoked after the namespace switch.
	return inNsfunc(int(origns))
}

func programGateway(path string, gw net.IP) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return err
	}
	defer origns.Close()

	f, err := os.OpenFile(path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", path, err)
	}
	defer f.Close()

	nsFD := f.Fd()
	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer netns.Set(origns)

	gwRoutes, err := netlink.RouteGet(gw)
	if err != nil {
		return fmt.Errorf("route for the gateway could not be found: %v", err)
	}

	return netlink.RouteAdd(&netlink.Route{
		Scope:     netlink.SCOPE_UNIVERSE,
		LinkIndex: gwRoutes[0].LinkIndex,
		Gw:        gw,
	})
}

func (n *networkNamespace) AddInterface(i *Interface) error {
	n.Lock()
	i.DstName = fmt.Sprintf("%s%d", i.DstName, n.nextIfIndex)
	n.nextIfIndex++
	n.Unlock()

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return err
	}
	defer origns.Close()

	f, err := os.OpenFile(n.path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", n.path, err)
	}
	defer f.Close()

	// Find the network interface identified by the SrcName attribute.
	iface, err := netlink.LinkByName(i.SrcName)
	if err != nil {
		return err
	}

	// Move the network interface to the destination namespace.
	nsFD := f.Fd()
	if err := netlink.LinkSetNsFd(iface, int(nsFD)); err != nil {
		return err
	}

	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer netns.Set(origns)

	// Down the interface before configuring
	if err := netlink.LinkSetDown(iface); err != nil {
		return err
	}

	// Configure the interface now this is moved in the proper namespace.
	if err := configureInterface(iface, i); err != nil {
		return err
	}

	// Up the interface.
	if err := netlink.LinkSetUp(iface); err != nil {
		return err
	}

	n.Lock()
	n.sinfo.Interfaces = append(n.sinfo.Interfaces, i)
	n.Unlock()

	return nil
}

func (n *networkNamespace) RemoveInterface(i *Interface) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	origns, err := netns.Get()
	if err != nil {
		return err
	}
	defer origns.Close()

	f, err := os.OpenFile(n.path, os.O_RDONLY, 0)
	if err != nil {
		return fmt.Errorf("failed get network namespace %q: %v", n.path, err)
	}
	defer f.Close()

	nsFD := f.Fd()
	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		return err
	}
	defer netns.Set(origns)

	// Find the network inteerface identified by the DstName attribute.
	iface, err := netlink.LinkByName(i.DstName)
	if err != nil {
		return err
	}

	// Down the interface before configuring
	if err := netlink.LinkSetDown(iface); err != nil {
		return err
	}

	err = netlink.LinkSetName(iface, i.SrcName)
	if err != nil {
		fmt.Println("LinkSetName failed: ", err)
		return err
	}

	// Move the network interface to caller namespace.
	if err := netlink.LinkSetNsFd(iface, int(origns)); err != nil {
		fmt.Println("LinkSetNsPid failed: ", err)
		return err
	}

	n.Lock()
	for index, intf := range n.sinfo.Interfaces {
		if intf == i {
			n.sinfo.Interfaces = append(n.sinfo.Interfaces[:index], n.sinfo.Interfaces[index+1:]...)
			break
		}
	}
	n.Unlock()

	return nil
}

func reexecSetupResolver() {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	if len(os.Args) < 4 {
		log.Error("invalid number of arguments..")
		os.Exit(1)
	}

	resolverIP, ipPort, _ := net.SplitHostPort(os.Args[2])
	_, tcpPort, _ := net.SplitHostPort(os.Args[3])
	rules := [][]string{
		{"-t", "nat", "-I", outputChain, "-d", resolverIP, "-p", "udp", "--dport", dnsPort, "-j", "DNAT", "--to-destination", os.Args[2]},
		{"-t", "nat", "-I", postroutingchain, "-s", resolverIP, "-p", "udp", "--sport", ipPort, "-j", "SNAT", "--to-source", ":" + dnsPort},
		{"-t", "nat", "-I", outputChain, "-d", resolverIP, "-p", "tcp", "--dport", dnsPort, "-j", "DNAT", "--to-destination", os.Args[3]},
		{"-t", "nat", "-I", postroutingchain, "-s", resolverIP, "-p", "tcp", "--sport", tcpPort, "-j", "SNAT", "--to-source", ":" + dnsPort},
	}

	f, err := os.OpenFile(os.Args[1], os.O_RDONLY, 0)
	if err != nil {
		log.Errorf("failed get network namespace %q: %v", os.Args[1], err)
		os.Exit(2)
	}
	defer f.Close()

	nsFD := f.Fd()
	if err = netns.Set(netns.NsHandle(nsFD)); err != nil {
		log.Errorf("setting into container net ns %v failed, %v", os.Args[1], err)
		os.Exit(3)
	}

	// insert outputChain and postroutingchain
	err = iptables.RawCombinedOutputNative("-t", "nat", "-C", "OUTPUT", "-d", resolverIP, "-j", outputChain)
	if err == nil {
		iptables.RawCombinedOutputNative("-t", "nat", "-F", outputChain)
	} else {
		iptables.RawCombinedOutputNative("-t", "nat", "-N", outputChain)
		iptables.RawCombinedOutputNative("-t", "nat", "-I", "OUTPUT", "-d", resolverIP, "-j", outputChain)
	}

	err = iptables.RawCombinedOutputNative("-t", "nat", "-C", "POSTROUTING", "-d", resolverIP, "-j", postroutingchain)
	if err == nil {
		iptables.RawCombinedOutputNative("-t", "nat", "-F", postroutingchain)
	} else {
		iptables.RawCombinedOutputNative("-t", "nat", "-N", postroutingchain)
		iptables.RawCombinedOutputNative("-t", "nat", "-I", "POSTROUTING", "-d", resolverIP, "-j", postroutingchain)
	}

	for _, rule := range rules {
		if iptables.RawCombinedOutputNative(rule...) != nil {
			log.Errorf("setting up rule failed, %v", rule)
		}
	}
}

func Exec(fd *os.File, cb func() error) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	newns := vishnetns.NsHandle(int(fd.Fd()))
	origns, _ := vishnetns.Get()
	defer origns.Close()

	if err := vishnetns.Set(newns); err != nil {
		return fmt.Errorf("set netns: %s", err)
	}

	err := cb()
	mustSetNs(origns) // if this happens we definitely can't recover
	return err
}