More robust MAC address matching

pkg/drivers/common.go

@@ -18,11 +18,12 @@ package drivers
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io"
+	"net"
 	"os"
 	"path/filepath"
-	"regexp"
 	"strings"
 	"syscall"
 
@@ -40,8 +41,6 @@ import (
 // LeasesPath is the path to dhcpd leases
 const LeasesPath = "/var/db/dhcpd_leases"
 
-var leadingZeroRegexp = regexp.MustCompile(`0([A-Fa-f0-9](:|$))`)
-
 // This file is for common code shared among internal machine drivers
 // Code here should not be called from within minikube
 
@@ -190,7 +189,7 @@ func fixMachinePermissions(path string) error {
 type DHCPEntry struct {
 	Name      string
 	IPAddress string
-	HWAddress string
+	HWAddress net.HardwareAddr
 	ID        string
 	Lease     string
 }
@@ -201,6 +200,13 @@ func GetIPAddressByMACAddress(mac string) (string, error) {
 }
 
 func getIPAddressFromFile(mac, path string) (string, error) {
+	// Due to https://openradar.appspot.com/FB15382970 we need to parse the MAC
+	// address and compare the bytes.
+	macAddress, err := parseMAC(mac)
+	if err != nil {
+		return "", err
+	}
+
 	log.Debugf("Searching for %s in %s ...", mac, path)
 	file, err := os.Open(path)
 	if err != nil {
@@ -215,7 +221,10 @@ func getIPAddressFromFile(mac, path string) (string, error) {
 	log.Debugf("Found %d entries in %s!", len(dhcpEntries), path)
 	for _, dhcpEntry := range dhcpEntries {
 		log.Debugf("dhcp entry: %+v", dhcpEntry)
-		if dhcpEntry.HWAddress == mac {
+		if dhcpEntry.HWAddress == nil {
+			continue
+		}
+		if bytes.Equal(dhcpEntry.HWAddress, macAddress) {
 			log.Debugf("Found match: %s", mac)
 			return dhcpEntry.IPAddress, nil
 		}
@@ -252,7 +261,13 @@ func parseDHCPdLeasesFile(file io.Reader) ([]DHCPEntry, error) {
 			dhcpEntry.IPAddress = val
 		case "hw_address":
 			// The mac addresses have a '1,' at the start.
-			dhcpEntry.HWAddress = val[2:]
+			macAddress, err := parseMAC(val[2:])
+			if err != nil {
+				log.Warnf("unable to parse hw_address in dhcp leases file: %q: %s",
+					val[2:], err)
+				continue
+			}
+			dhcpEntry.HWAddress = macAddress
 		case "identifier":
 			dhcpEntry.ID = val
 		case "lease":
@@ -264,7 +279,17 @@ func parseDHCPdLeasesFile(file io.Reader) ([]DHCPEntry, error) {
 	return dhcpEntries, scanner.Err()
 }
 
-// TrimMacAddress trimming "0" of the ten's digit
-func TrimMacAddress(rawUUID string) string {
-	return leadingZeroRegexp.ReplaceAllString(rawUUID, "$1")
+// parseMAC parse both standard fixeed size MAC address "%02x:..." and the
+// variable size MAC address on drawin "%x:...".
+func parseMAC(mac string) (net.HardwareAddr, error) {
+	hw := make(net.HardwareAddr, 6)
+	n, err := fmt.Sscanf(mac, "%x:%x:%x:%x:%x:%x",
+		&hw[0], &hw[1], &hw[2], &hw[3], &hw[4], &hw[5])
+	if n != len(hw) {
+		return nil, fmt.Errorf("invalid MAC address: %q", mac)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse MAC address: %q: %s", mac, err)
+	}
+	return hw, nil
 }

pkg/drivers/common_test.go

@@ -54,6 +54,13 @@ var validLeases = []byte(`{
         identifier=1,a2:b3:c4:d5:e6:f7
         lease=0x597e1267
 }
+{
+        name=bootp
+        ip_address=192.168.105.2
+        hw_address=1,8e:1:99:9c:54:b1
+        identifier=1,8e:1:99:9c:54:b1
+        lease=0x597e1268
+}
 {
         name=bar
         ip_address=192.168.64.3
@@ -98,6 +105,14 @@ func Test_getIpAddressFromFile(t *testing.T) {
 			"1.2.3.4",
 			false,
 		},
+		{
+			// bootp use "%x" format instead of "%02x"
+			// https://openradar.appspot.com/FB15382970
+			"valid-bootp",
+			args{"8e:01:99:9c:54:b1", dhcpFile},
+			"192.168.105.2",
+			false,
+		},
 		{
 			"duplicate",
 			args{"a4:b5:c6:d7:e8:f9", dhcpFile},

pkg/drivers/hyperkit/driver.go

@@ -261,8 +261,6 @@ func (d *Driver) Start() error {
 		return errors.Wrap(err, "getting MAC address from UUID")
 	}
 
-	// Need to strip 0's
-	mac = pkgdrivers.TrimMacAddress(mac)
 	log.Debugf("Generated MAC %s", mac)
 
 	log.Debugf("Starting with cmdline: %s", d.Cmdline)

pkg/drivers/qemu/qemu.go

@@ -505,10 +505,7 @@ func (d *Driver) Start() error {
 	case "socket_vmnet":
 		var err error
 		getIP := func() error {
-			// QEMU requires MAC address with leading 0s
-			// But socket_vmnet writes the MAC address to the dhcp leases file with leading 0s stripped
-			mac := pkgdrivers.TrimMacAddress(d.MACAddress)
-			d.IPAddress, err = pkgdrivers.GetIPAddressByMACAddress(mac)
+			d.IPAddress, err = pkgdrivers.GetIPAddressByMACAddress(d.MACAddress)
 			if err != nil {
 				return errors.Wrap(err, "failed to get IP address")
 			}

pkg/drivers/vfkit/vfkit.go

@@ -265,8 +265,6 @@ func (d *Driver) Start() error {
 		return err
 	}
 
-	// Need to strip 0's
-	mac = pkgdrivers.TrimMacAddress(mac)
 	if err := d.setupIP(mac); err != nil {
 		return err
 	}