1 files changed, 15 insertions, 5 deletions
diff --git a/pkg/tcpip/header/eth.go b/pkg/tcpip/header/eth.go
index b1e92d2d7..95ade0e5c 100644
--- a/pkg/tcpip/header/eth.go
+++ b/pkg/tcpip/header/eth.go
@@ -53,6 +53,10 @@ const (
 	// (all bits set to 0).
 	unspecifiedEthernetAddress = tcpip.LinkAddress("\x00\x00\x00\x00\x00\x00")
 
+	// EthernetBroadcastAddress is an ethernet address that addresses every node
+	// on a local link.
+	EthernetBroadcastAddress = tcpip.LinkAddress("\xff\xff\xff\xff\xff\xff")
+
 	// unicastMulticastFlagMask is the mask of the least significant bit in
 	// the first octet (in network byte order) of an ethernet address that
 	// determines whether the ethernet address is a unicast or multicast. If
@@ -113,25 +117,31 @@ func (b Ethernet) Encode(e *EthernetFields) {
 	copy(b[dstMAC:][:EthernetAddressSize], e.DstAddr)
 }
 
-// IsValidUnicastEthernetAddress returns true if addr is a valid unicast
+// IsMulticastEthernetAddress returns true if the address is a multicast
+// ethernet address.
+func IsMulticastEthernetAddress(addr tcpip.LinkAddress) bool {
+	if len(addr) != EthernetAddressSize {
+		return false
+	}
+
+	return addr[unicastMulticastFlagByteIdx]&unicastMulticastFlagMask != 0
+}
+
+// IsValidUnicastEthernetAddress returns true if the address is a unicast
 // ethernet address.
 func IsValidUnicastEthernetAddress(addr tcpip.LinkAddress) bool {
-	// Must be of the right length.
 	if len(addr) != EthernetAddressSize {
 		return false
 	}
 
-	// Must not be unspecified.
 	if addr == unspecifiedEthernetAddress {
 		return false
 	}
 
-	// Must not be a multicast.
 	if addr[unicastMulticastFlagByteIdx]&unicastMulticastFlagMask != 0 {
 		return false
 	}
 
-	// addr is a valid unicast ethernet address.
 	return true
 }