net: parse addresses without separators in ParseMac

IEEE EUI guidelines states that "an EUI-48 can be represented in the IEEE RA
hexadecimal (hex) form with the octets separated by hyphens, or as a pure
base-16 numerical representation without hyphens"
(https://standards.ieee.org/wp-content/uploads/import/documents/tutorials/eui.pdf p.9).
The latter form is used in Azure Instance Metadata Service
(https://github.com/Azure/azure-container-networking/pull/4122) among others.

Fixes #66682

Change-Id: Id66c23d50ebb1fed1f3bdb5cf3822a8fd60b886d
GitHub-Last-Rev: 77900cc1a6
GitHub-Pull-Request: golang/go#76387
Reviewed-on: https://go-review.googlesource.com/c/go/+/722720
Auto-Submit: Damien Neil <dneil@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/net/mac.go

@@ -36,8 +36,9 @@ func (a HardwareAddr) String() string {
 //	0000.5e00.5301
 //	0200.5e10.0000.0001
 //	0000.0000.fe80.0000.0000.0000.0200.5e10.0000.0001
+//	00005e005301
 func ParseMAC(s string) (hw HardwareAddr, err error) {
-	if len(s) < 14 {
+	if len(s) < 12 {
 		goto error
 	}
 
@@ -77,7 +78,23 @@ func ParseMAC(s string) (hw HardwareAddr, err error) {
 			x += 5
 		}
 	} else {
-		goto error
+		if len(s)%2 != 0 {
+			goto error
+		}
+
+		n := len(s) / 2
+		if n != 6 && n != 8 && n != 20 {
+			goto error
+		}
+
+		hw = make(HardwareAddr, len(s)/2)
+		for x, i := 0, 0; i < n; i++ {
+			var ok bool
+			if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
+				goto error
+			}
+			x += 2
+		}
 	}
 	return hw, nil
 

src/net/mac_test.go

@@ -19,11 +19,13 @@ var parseMACTests = []struct {
 	{"00:00:5e:00:53:01", HardwareAddr{0x00, 0x00, 0x5e, 0x00, 0x53, 0x01}, ""},
 	{"00-00-5e-00-53-01", HardwareAddr{0x00, 0x00, 0x5e, 0x00, 0x53, 0x01}, ""},
 	{"0000.5e00.5301", HardwareAddr{0x00, 0x00, 0x5e, 0x00, 0x53, 0x01}, ""},
+	{"00005e005301", HardwareAddr{0x00, 0x00, 0x5e, 0x00, 0x53, 0x01}, ""},
 
 	// See RFC 7042, Section 2.2.2.
 	{"02:00:5e:10:00:00:00:01", HardwareAddr{0x02, 0x00, 0x5e, 0x10, 0x00, 0x00, 0x00, 0x01}, ""},
 	{"02-00-5e-10-00-00-00-01", HardwareAddr{0x02, 0x00, 0x5e, 0x10, 0x00, 0x00, 0x00, 0x01}, ""},
 	{"0200.5e10.0000.0001", HardwareAddr{0x02, 0x00, 0x5e, 0x10, 0x00, 0x00, 0x00, 0x01}, ""},
+	{"02005e1000000001", HardwareAddr{0x02, 0x00, 0x5e, 0x10, 0x00, 0x00, 0x00, 0x01}, ""},
 
 	// See RFC 4391, Section 9.1.1.
 	{
@@ -53,6 +55,15 @@ var parseMACTests = []struct {
 		},
 		"",
 	},
+	{
+		"00000000fe8000000000000002005e1000000001",
+		HardwareAddr{
+			0x00, 0x00, 0x00, 0x00,
+			0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			0x02, 0x00, 0x5e, 0x10, 0x00, 0x00, 0x00, 0x01,
+		},
+		"",
+	},
 
 	{"ab:cd:ef:AB:CD:EF", HardwareAddr{0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef}, ""},
 	{"ab:cd:ef:AB:CD:EF:ab:cd", HardwareAddr{0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef, 0xab, 0xcd}, ""},
@@ -78,6 +89,7 @@ var parseMACTests = []struct {
 	{"01:02-03-04-05-06", nil, "invalid MAC address"},
 	{"0123:4567:89AF", nil, "invalid MAC address"},
 	{"0123-4567-89AF", nil, "invalid MAC address"},
+	{"0123456789AF0", nil, "invalid MAC address"},
 }
 
 func TestParseMAC(t *testing.T) {