bugfix: bind an address for stream server

Signed-off-by: YaoZengzeng <[email protected]>

cri/stream/interface.go

@@ -0,0 +1,380 @@
+package stream
+
+// NOTE: The code in this file is directly copy from package "k8s.io/apimachinery/pkg/util/net".
+// We do this because we don't want to vendor too many irrelevant packages and try to make
+// the code simple and clean :)
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net"
+	"os"
+
+	"strings"
+
+	"github.com/golang/glog"
+)
+
+type AddressFamily uint
+
+const (
+	familyIPv4 AddressFamily = 4
+	familyIPv6 AddressFamily = 6
+)
+
+const (
+	ipv4RouteFile = "/proc/net/route"
+	ipv6RouteFile = "/proc/net/ipv6_route"
+)
+
+type Route struct {
+	Interface   string
+	Destination net.IP
+	Gateway     net.IP
+	Family      AddressFamily
+}
+
+type RouteFile struct {
+	name  string
+	parse func(input io.Reader) ([]Route, error)
+}
+
+var (
+	v4File = RouteFile{name: ipv4RouteFile, parse: getIPv4DefaultRoutes}
+	v6File = RouteFile{name: ipv6RouteFile, parse: getIPv6DefaultRoutes}
+)
+
+func (rf RouteFile) extract() ([]Route, error) {
+	file, err := os.Open(rf.name)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	return rf.parse(file)
+}
+
+// getIPv4DefaultRoutes obtains the IPv4 routes, and filters out non-default routes.
+func getIPv4DefaultRoutes(input io.Reader) ([]Route, error) {
+	routes := []Route{}
+	scanner := bufio.NewReader(input)
+	for {
+		line, err := scanner.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		//ignore the headers in the route info
+		if strings.HasPrefix(line, "Iface") {
+			continue
+		}
+		fields := strings.Fields(line)
+		// Interested in fields:
+		//  0 - interface name
+		//  1 - destination address
+		//  2 - gateway
+		dest, err := parseIP(fields[1], familyIPv4)
+		if err != nil {
+			return nil, err
+		}
+		gw, err := parseIP(fields[2], familyIPv4)
+		if err != nil {
+			return nil, err
+		}
+		if !dest.Equal(net.IPv4zero) {
+			continue
+		}
+		routes = append(routes, Route{
+			Interface:   fields[0],
+			Destination: dest,
+			Gateway:     gw,
+			Family:      familyIPv4,
+		})
+	}
+	return routes, nil
+}
+
+func getIPv6DefaultRoutes(input io.Reader) ([]Route, error) {
+	routes := []Route{}
+	scanner := bufio.NewReader(input)
+	for {
+		line, err := scanner.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		fields := strings.Fields(line)
+		// Interested in fields:
+		//  0 - destination address
+		//  4 - gateway
+		//  9 - interface name
+		dest, err := parseIP(fields[0], familyIPv6)
+		if err != nil {
+			return nil, err
+		}
+		gw, err := parseIP(fields[4], familyIPv6)
+		if err != nil {
+			return nil, err
+		}
+		if !dest.Equal(net.IPv6zero) {
+			continue
+		}
+		if gw.Equal(net.IPv6zero) {
+			continue // loopback
+		}
+		routes = append(routes, Route{
+			Interface:   fields[9],
+			Destination: dest,
+			Gateway:     gw,
+			Family:      familyIPv6,
+		})
+	}
+	return routes, nil
+}
+
+// parseIP takes the hex IP address string from route file and converts it
+// to a net.IP address. For IPv4, the value must be converted to big endian.
+func parseIP(str string, family AddressFamily) (net.IP, error) {
+	if str == "" {
+		return nil, fmt.Errorf("input is nil")
+	}
+	bytes, err := hex.DecodeString(str)
+	if err != nil {
+		return nil, err
+	}
+	if family == familyIPv4 {
+		if len(bytes) != net.IPv4len {
+			return nil, fmt.Errorf("invalid IPv4 address in route")
+		}
+		return net.IP([]byte{bytes[3], bytes[2], bytes[1], bytes[0]}), nil
+	}
+	// Must be IPv6
+	if len(bytes) != net.IPv6len {
+		return nil, fmt.Errorf("invalid IPv6 address in route")
+	}
+	return net.IP(bytes), nil
+}
+
+func isInterfaceUp(intf *net.Interface) bool {
+	if intf == nil {
+		return false
+	}
+	if intf.Flags&net.FlagUp != 0 {
+		glog.V(4).Infof("Interface %v is up", intf.Name)
+		return true
+	}
+	return false
+}
+
+func isLoopbackOrPointToPoint(intf *net.Interface) bool {
+	return intf.Flags&(net.FlagLoopback|net.FlagPointToPoint) != 0
+}
+
+// getMatchingGlobalIP returns the first valid global unicast address of the given
+// 'family' from the list of 'addrs'.
+func getMatchingGlobalIP(addrs []net.Addr, family AddressFamily) (net.IP, error) {
+	if len(addrs) > 0 {
+		for i := range addrs {
+			glog.V(4).Infof("Checking addr  %s.", addrs[i].String())
+			ip, _, err := net.ParseCIDR(addrs[i].String())
+			if err != nil {
+				return nil, err
+			}
+			if memberOf(ip, family) {
+				if ip.IsGlobalUnicast() {
+					glog.V(4).Infof("IP found %v", ip)
+					return ip, nil
+				} else {
+					glog.V(4).Infof("Non-global unicast address found %v", ip)
+				}
+			} else {
+				glog.V(4).Infof("%v is not an IPv%d address", ip, int(family))
+			}
+
+		}
+	}
+	return nil, nil
+}
+
+// getIPFromInterface gets the IPs on an interface and returns a global unicast address, if any. The
+// interface must be up, the IP must in the family requested, and the IP must be a global unicast address.
+func getIPFromInterface(intfName string, forFamily AddressFamily, nw networkInterfacer) (net.IP, error) {
+	intf, err := nw.InterfaceByName(intfName)
+	if err != nil {
+		return nil, err
+	}
+	if isInterfaceUp(intf) {
+		addrs, err := nw.Addrs(intf)
+		if err != nil {
+			return nil, err
+		}
+		glog.V(4).Infof("Interface %q has %d addresses :%v.", intfName, len(addrs), addrs)
+		matchingIP, err := getMatchingGlobalIP(addrs, forFamily)
+		if err != nil {
+			return nil, err
+		}
+		if matchingIP != nil {
+			glog.V(4).Infof("Found valid IPv%d address %v for interface %q.", int(forFamily), matchingIP, intfName)
+			return matchingIP, nil
+		}
+	}
+	return nil, nil
+}
+
+// memberOF tells if the IP is of the desired family. Used for checking interface addresses.
+func memberOf(ip net.IP, family AddressFamily) bool {
+	if ip.To4() != nil {
+		return family == familyIPv4
+	} else {
+		return family == familyIPv6
+	}
+}
+
+// chooseIPFromHostInterfaces looks at all system interfaces, trying to find one that is up that
+// has a global unicast address (non-loopback, non-link local, non-point2point), and returns the IP.
+// Searches for IPv4 addresses, and then IPv6 addresses.
+func chooseIPFromHostInterfaces(nw networkInterfacer) (net.IP, error) {
+	intfs, err := nw.Interfaces()
+	if err != nil {
+		return nil, err
+	}
+	if len(intfs) == 0 {
+		return nil, fmt.Errorf("no interfaces found on host.")
+	}
+	for _, family := range []AddressFamily{familyIPv4, familyIPv6} {
+		glog.V(4).Infof("Looking for system interface with a global IPv%d address", uint(family))
+		for _, intf := range intfs {
+			if !isInterfaceUp(&intf) {
+				glog.V(4).Infof("Skipping: down interface %q", intf.Name)
+				continue
+			}
+			if isLoopbackOrPointToPoint(&intf) {
+				glog.V(4).Infof("Skipping: LB or P2P interface %q", intf.Name)
+				continue
+			}
+			addrs, err := nw.Addrs(&intf)
+			if err != nil {
+				return nil, err
+			}
+			if len(addrs) == 0 {
+				glog.V(4).Infof("Skipping: no addresses on interface %q", intf.Name)
+				continue
+			}
+			for _, addr := range addrs {
+				ip, _, err := net.ParseCIDR(addr.String())
+				if err != nil {
+					return nil, fmt.Errorf("Unable to parse CIDR for interface %q: %s", intf.Name, err)
+				}
+				if !memberOf(ip, family) {
+					glog.V(4).Infof("Skipping: no address family match for %q on interface %q.", ip, intf.Name)
+					continue
+				}
+				// TODO: Decide if should open up to allow IPv6 LLAs in future.
+				if !ip.IsGlobalUnicast() {
+					glog.V(4).Infof("Skipping: non-global address %q on interface %q.", ip, intf.Name)
+					continue
+				}
+				glog.V(4).Infof("Found global unicast address %q on interface %q.", ip, intf.Name)
+				return ip, nil
+			}
+		}
+	}
+	return nil, fmt.Errorf("no acceptable interface with global unicast address found on host")
+}
+
+// ChooseHostInterface is a method used fetch an IP for a daemon.
+// If there is no routing info file, it will choose a global IP from the system
+// interfaces. Otherwise, it will use IPv4 and IPv6 route information to return the
+// IP of the interface with a gateway on it (with priority given to IPv4). For a node
+// with no internet connection, it returns error.
+func ChooseHostInterface() (net.IP, error) {
+	var nw networkInterfacer = networkInterface{}
+	if _, err := os.Stat(ipv4RouteFile); os.IsNotExist(err) {
+		return chooseIPFromHostInterfaces(nw)
+	}
+	routes, err := getAllDefaultRoutes()
+	if err != nil {
+		return nil, err
+	}
+	return chooseHostInterfaceFromRoute(routes, nw)
+}
+
+// networkInterfacer defines an interface for several net library functions. Production
+// code will forward to net library functions, and unit tests will override the methods
+// for testing purposes.
+type networkInterfacer interface {
+	InterfaceByName(intfName string) (*net.Interface, error)
+	Addrs(intf *net.Interface) ([]net.Addr, error)
+	Interfaces() ([]net.Interface, error)
+}
+
+// networkInterface implements the networkInterfacer interface for production code, just
+// wrapping the underlying net library function calls.
+type networkInterface struct{}
+
+func (_ networkInterface) InterfaceByName(intfName string) (*net.Interface, error) {
+	return net.InterfaceByName(intfName)
+}
+
+func (_ networkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
+	return intf.Addrs()
+}
+
+func (_ networkInterface) Interfaces() ([]net.Interface, error) {
+	return net.Interfaces()
+}
+
+// getAllDefaultRoutes obtains IPv4 and IPv6 default routes on the node. If unable
+// to read the IPv4 routing info file, we return an error. If unable to read the IPv6
+// routing info file (which is optional), we'll just use the IPv4 route information.
+// Using all the routing info, if no default routes are found, an error is returned.
+func getAllDefaultRoutes() ([]Route, error) {
+	routes, err := v4File.extract()
+	if err != nil {
+		return nil, err
+	}
+	v6Routes, _ := v6File.extract()
+	routes = append(routes, v6Routes...)
+	if len(routes) == 0 {
+		return nil, fmt.Errorf("No default routes.")
+	}
+	return routes, nil
+}
+
+// chooseHostInterfaceFromRoute cycles through each default route provided, looking for a
+// global IP address from the interface for the route. Will first look all each IPv4 route for
+// an IPv4 IP, and then will look at each IPv6 route for an IPv6 IP.
+func chooseHostInterfaceFromRoute(routes []Route, nw networkInterfacer) (net.IP, error) {
+	for _, family := range []AddressFamily{familyIPv4, familyIPv6} {
+		glog.V(4).Infof("Looking for default routes with IPv%d addresses", uint(family))
+		for _, route := range routes {
+			if route.Family != family {
+				continue
+			}
+			glog.V(4).Infof("Default route transits interface %q", route.Interface)
+			finalIP, err := getIPFromInterface(route.Interface, family, nw)
+			if err != nil {
+				return nil, err
+			}
+			if finalIP != nil {
+				glog.V(4).Infof("Found active IP %v ", finalIP)
+				return finalIP, nil
+			}
+		}
+	}
+	glog.V(4).Infof("No active IP found by looking at default routes")
+	return nil, fmt.Errorf("unable to select an IP from default routes.")
+}
+
+// If bind-address is usable, return it directly
+// If bind-address is not usable (unset, 0.0.0.0, or loopback), we will use the host's default
+// interface.
+func ChooseBindAddress(bindAddress net.IP) (net.IP, error) {
+	if bindAddress == nil || bindAddress.IsUnspecified() || bindAddress.IsLoopback() {
+		hostIP, err := ChooseHostInterface()
+		if err != nil {
+			return nil, err
+		}
+		bindAddress = hostIP
+	}
+	return bindAddress, nil
+}