Detect looped-back NDP DAD messages

...as per RFC 7527.

If a looped-back DAD message is received, do not fail DAD since our own
DAD message does not indicate that a neighbor has the address assigned.

Test: ndp_test.TestDADResolveLoopback
PiperOrigin-RevId: 363224288

1 files changed, 11 insertions, 3 deletions

diff --git a/pkg/tcpip/header/ndpoptionidentifier_string.go b/pkg/tcpip/header/ndpoptionidentifier_string.go
index 6fe9a336b..83f94a730 100644
--- a/pkg/tcpip/header/ndpoptionidentifier_string.go
+++ b/pkg/tcpip/header/ndpoptionidentifier_string.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Code generated by "stringer -type NDPOptionIdentifier ."; DO NOT EDIT.
+// Code generated by "stringer -type NDPOptionIdentifier"; DO NOT EDIT.
 
 package header
 
@@ -25,12 +25,16 @@ func _() {
 	_ = x[NDPSourceLinkLayerAddressOptionType-1]
 	_ = x[NDPTargetLinkLayerAddressOptionType-2]
 	_ = x[NDPPrefixInformationType-3]
+	_ = x[NDPNonceOptionType-14]
 	_ = x[NDPRecursiveDNSServerOptionType-25]
+	_ = x[NDPDNSSearchListOptionType-31]
 }
 
 const (
 	_NDPOptionIdentifier_name_0 = "NDPSourceLinkLayerAddressOptionTypeNDPTargetLinkLayerAddressOptionTypeNDPPrefixInformationType"
-	_NDPOptionIdentifier_name_1 = "NDPRecursiveDNSServerOptionType"
+	_NDPOptionIdentifier_name_1 = "NDPNonceOptionType"
+	_NDPOptionIdentifier_name_2 = "NDPRecursiveDNSServerOptionType"
+	_NDPOptionIdentifier_name_3 = "NDPDNSSearchListOptionType"
 )
 
 var (
@@ -42,8 +46,12 @@ func (i NDPOptionIdentifier) String() string {
 	case 1 <= i && i <= 3:
 		i -= 1
 		return _NDPOptionIdentifier_name_0[_NDPOptionIdentifier_index_0[i]:_NDPOptionIdentifier_index_0[i+1]]
-	case i == 25:
+	case i == 14:
 		return _NDPOptionIdentifier_name_1
+	case i == 25:
+		return _NDPOptionIdentifier_name_2
+	case i == 31:
+		return _NDPOptionIdentifier_name_3
 	default:
 		return "NDPOptionIdentifier(" + strconv.FormatInt(int64(i), 10) + ")"
 	}