Golang netlink.LinkByName函數代碼示例

// ConfigureIface takes the result of IPAM plugin and
// applies to the ifName interface
func ConfigureIface(ifName string, res *Result) error {
	link, err := netlink.LinkByName(ifName)
	if err != nil {
		return fmt.Errorf("failed to lookup %q: %v", ifName, err)
	}

	if err := netlink.LinkSetUp(link); err != nil {
		return fmt.Errorf("failed to set %q UP: %v", ifName, err)
	}

	// TODO(eyakubovich): IPv6
	addr := &netlink.Addr{IPNet: &res.IP4.IP, Label: ""}
	if err = netlink.AddrAdd(link, addr); err != nil {
		return fmt.Errorf("failed to add IP addr to %q: %v", ifName, err)
	}

	for _, r := range res.IP4.Routes {
		gw := r.GW
		if gw == nil {
			gw = res.IP4.Gateway
		}
		if err = ip.AddRoute(&r.Dst, gw, link); err != nil {
			// we skip over duplicate routes as we assume the first one wins
			if !os.IsExist(err) {
				return fmt.Errorf("failed to add route '%v via %v dev %v': %v", r.Dst, gw, ifName, err)
			}
		}
	}

	return nil
}

func setupHostVeth(vethName string, ipConf *types.IPConfig) error {
	// hostVeth moved namespaces and may have a new ifindex
	veth, err := netlink.LinkByName(vethName)
	if err != nil {
		return fmt.Errorf("failed to lookup %q: %v", vethName, err)
	}

	// TODO(eyakubovich): IPv6
	ipn := &net.IPNet{
		IP:   ipConf.Gateway,
		Mask: net.CIDRMask(32, 32),
	}
	addr := &netlink.Addr{IPNet: ipn, Label: ""}
	if err = netlink.AddrAdd(veth, addr); err != nil {
		return fmt.Errorf("failed to add IP addr (%#v) to veth: %v", ipn, err)
	}

	ipn = &net.IPNet{
		IP:   ipConf.IP.IP,
		Mask: net.CIDRMask(32, 32),
	}
	// dst happens to be the same as IP/net of host veth
	if err = ip.AddHostRoute(ipn, nil, veth); err != nil && !os.IsExist(err) {
		return fmt.Errorf("failed to add route on host: %v", err)
	}

	return nil
}

// SetupVeth sets up a virtual ethernet link.
// Should be in container netns.
func SetupVeth(contVethName string, mtu int, hostNS *os.File) (hostVeth, contVeth netlink.Link, err error) {
	var hostVethName string
	hostVethName, contVeth, err = makeVeth(contVethName, mtu)
	if err != nil {
		return
	}

	if err = netlink.LinkSetUp(contVeth); err != nil {
		err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
		return
	}

	hostVeth, err = netlink.LinkByName(hostVethName)
	if err != nil {
		err = fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
		return
	}

	if err = netlink.LinkSetUp(hostVeth); err != nil {
		err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
		return
	}

	if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
		err = fmt.Errorf("failed to move veth to host netns: %v", err)
		return
	}

	return
}

// SetupVeth sets up a virtual ethernet link.
// Should be in container netns.
// TODO(eyakubovich): get rid of entropy and ask kernel to pick name via pattern
func SetupVeth(entropy, contVethName string, mtu int, hostNS *os.File) (hostVeth, contVeth netlink.Link, err error) {
	// NetworkManager (recent versions) will ignore veth devices that start with "veth"
	hostVethName := RandomVethName(entropy)
	hostVeth, err = makeVeth(hostVethName, contVethName, mtu)
	if err != nil {
		err = fmt.Errorf("failed to make veth pair: %v", err)
		return
	}

	if err = netlink.LinkSetUp(hostVeth); err != nil {
		err = fmt.Errorf("failed to set %q up: %v", hostVethName, err)
		return
	}

	contVeth, err = netlink.LinkByName(contVethName)
	if err != nil {
		err = fmt.Errorf("failed to lookup %q: %v", contVethName, err)
		return
	}

	if err = netlink.LinkSetUp(contVeth); err != nil {
		err = fmt.Errorf("failed to set %q up: %v", contVethName, err)
		return
	}

	if err = netlink.LinkSetNsFd(hostVeth, int(hostNS.Fd())); err != nil {
		err = fmt.Errorf("failed to move veth to host netns: %v", err)
		return
	}

	return
}

func setupVeth(netns string, br *netlink.Bridge, ifName string, mtu int, pr *plugin.Result) error {
	var hostVethName string

	err := ns.WithNetNSPath(netns, func(hostNS *os.File) error {
		// create the veth pair in the container and move host end into host netns
		hostVeth, _, err := ip.SetupVeth(netns, ifName, mtu, hostNS)
		if err != nil {
			return err
		}

		if err = plugin.ConfigureIface(ifName, pr); err != nil {
			return err
		}

		hostVethName = hostVeth.Attrs().Name
		return nil
	})
	if err != nil {
		return err
	}

	// need to lookup hostVeth again as its index has changed during ns move
	hostVeth, err := netlink.LinkByName(hostVethName)
	if err != nil {
		return fmt.Errorf("failed to lookup %q: %v", hostVethName, err)
	}

	// connect host veth end to the bridge
	if err = netlink.LinkSetMaster(hostVeth, br); err != nil {
		return fmt.Errorf("failed to connect %q to bridge %v: %v", hostVethName, br.Attrs().Name, err)
	}

	return nil
}

func createIpvlan(conf *NetConf, ifName string, netns *os.File) error {
	mode, err := modeFromString(conf.Mode)
	if err != nil {
		return err
	}

	m, err := netlink.LinkByName(conf.Master)
	if err != nil {
		return fmt.Errorf("failed to lookup master %q: %v", conf.Master, err)
	}

	mv := &netlink.IPVlan{
		LinkAttrs: netlink.LinkAttrs{
			MTU:         conf.MTU,
			Name:        ifName,
			ParentIndex: m.Attrs().Index,
			Namespace:   netlink.NsFd(int(netns.Fd())),
		},
		Mode: mode,
	}

	if err := netlink.LinkAdd(mv); err != nil {
		return fmt.Errorf("failed to create ipvlan: %v", err)
	}

	return err
}

func renameLink(curName, newName string) error {
	link, err := netlink.LinkByName(curName)
	if err != nil {
		return err
	}

	return netlink.LinkSetName(link, newName)
}

func bridgeByName(name string) (*netlink.Bridge, error) {
	l, err := netlink.LinkByName(name)
	if err != nil {
		return nil, fmt.Errorf("could not lookup %q: %v", name, err)
	}
	br, ok := l.(*netlink.Bridge)
	if !ok {
		return nil, fmt.Errorf("%q already exists but is not a bridge", name)
	}
	return br, nil
}

func loUp() error {
	lo, err := netlink.LinkByName("lo")
	if err != nil {
		return fmt.Errorf("failed to lookup lo: %v", err)
	}

	if err := netlink.LinkSetUp(lo); err != nil {
		return fmt.Errorf("failed to set lo up: %v", err)
	}

	return nil
}

// DelLinkByName removes an interface link.
func DelLinkByName(ifName string) error {
	iface, err := netlink.LinkByName(ifName)
	if err != nil {
		return fmt.Errorf("failed to lookup %q: %v", ifName, err)
	}

	if err = netlink.LinkDel(iface); err != nil {
		return fmt.Errorf("failed to delete %q: %v", ifName, err)
	}

	return nil
}

func getDefaultGW(family int) (string, error) {
	l, err := netlink.LinkByName("lo")
	if err != nil {
		return "", err
	}

	routes, err := netlink.RouteList(l, family)
	if err != nil {
		return "", err
	}

	return routes[0].Gw.String(), nil
}

func (an activeNet) IfName() string {
	if an.conf.Type == "macvlan" {
		// macvtap device passed as parameter to lkvm binary have different
		// kind of name, path to /dev/tapN made with N as link index
		link, err := netlink.LinkByName(an.runtime.IfName)
		if err != nil {
			log.Printf("Cannot get interface '%v': %v", an.runtime.IfName, err)
			return ""
		}
		return fmt.Sprintf("/dev/tap%d", link.Attrs().Index)
	}
	return an.runtime.IfName
}

// setupTapDevice creates persistent tap devices
// and returns a newly created netlink.Link structure
func setupTapDevice() (netlink.Link, error) {
	ifName, err := tuntap.CreatePersistentIface(tuntap.Tap)
	if err != nil {
		return nil, fmt.Errorf("tuntap persist %v", err)
	}
	link, err := netlink.LinkByName(ifName)
	if err != nil {
		return nil, fmt.Errorf("cannot find link %q: %v", ifName, err)
	}
	err = netlink.LinkSetUp(link)
	if err != nil {
		return nil, fmt.Errorf("cannot set link up %q: %v", ifName, err)
	}
	return link, nil
}

// DelLinkByNameAddr remove an interface returns its IP address
// of the specified family
func DelLinkByNameAddr(ifName string, family int) (*net.IPNet, error) {
	iface, err := netlink.LinkByName(ifName)
	if err != nil {
		return nil, fmt.Errorf("failed to lookup %q: %v", ifName, err)
	}

	addrs, err := netlink.AddrList(iface, family)
	if err != nil || len(addrs) == 0 {
		return nil, fmt.Errorf("failed to get IP addresses for %q: %v", ifName, err)
	}

	if err = netlink.LinkDel(iface); err != nil {
		return nil, fmt.Errorf("failed to delete %q: %v", ifName, err)
	}

	return addrs[0].IPNet, nil
}

// setupTapDevice creates persistent tap devices
// and returns a newly created netlink.Link structure
func setupTapDevice(podID types.UUID) (netlink.Link, error) {
	// network device names are limited to 16 characters
	// the suffix %d will be replaced by the kernel with a suitable number
	nameTemplate := fmt.Sprintf("rkt-%s-tap%%d", podID.String()[0:4])
	ifName, err := tuntap.CreatePersistentIface(nameTemplate, tuntap.Tap)
	if err != nil {
		return nil, fmt.Errorf("tuntap persist %v", err)
	}
	link, err := netlink.LinkByName(ifName)
	if err != nil {
		return nil, fmt.Errorf("cannot find link %q: %v", ifName, err)
	}
	err = netlink.LinkSetUp(link)
	if err != nil {
		return nil, fmt.Errorf("cannot set link up %q: %v", ifName, err)
	}
	return link, nil
}