1 files changed, 76 insertions, 5 deletions

diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go
index 06e0bace2..e6a6ad39b 100644
--- a/pkg/tcpip/header/ndp_options.go
+++ b/pkg/tcpip/header/ndp_options.go
@@ -17,6 +17,7 @@ package header
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"math"
 	"time"
 
@@ -24,13 +25,17 @@ import (
 )
 
 const (
-	// NDPTargetLinkLayerAddressOptionType is the type of the Target
-	// Link-Layer Address option, as per RFC 4861 section 4.6.1.
+	// NDPSourceLinkLayerAddressOptionType is the type of the Source Link Layer
+	// Address option, as per RFC 4861 section 4.6.1.
+	NDPSourceLinkLayerAddressOptionType = 1
+
+	// NDPTargetLinkLayerAddressOptionType is the type of the Target Link Layer
+	// Address option, as per RFC 4861 section 4.6.1.
 	NDPTargetLinkLayerAddressOptionType = 2
 
-	// ndpTargetEthernetLinkLayerAddressSize is the size of a Target
-	// Link Layer Option for an Ethernet address.
-	ndpTargetEthernetLinkLayerAddressSize = 8
+	// NDPLinkLayerAddressSize is the size of a Source or Target Link Layer
+	// Address option for an Ethernet address.
+	NDPLinkLayerAddressSize = 8
 
 	// NDPPrefixInformationType is the type of the Prefix Information
 	// option, as per RFC 4861 section 4.6.2.
@@ -189,6 +194,9 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) {
 		i.opts = i.opts[numBytes:]
 
 		switch t {
+		case NDPSourceLinkLayerAddressOptionType:
+			return NDPSourceLinkLayerAddressOption(body), false, nil
+
 		case NDPTargetLinkLayerAddressOptionType:
 			return NDPTargetLinkLayerAddressOption(body), false, nil
 
@@ -293,6 +301,8 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int {
 
 // NDPOption is the set of functions to be implemented by all NDP option types.
 type NDPOption interface {
+	fmt.Stringer
+
 	// Type returns the type of the receiver.
 	Type() uint8
 
@@ -368,6 +378,46 @@ func (b NDPOptionsSerializer) Length() int {
 	return l
 }
 
+// NDPSourceLinkLayerAddressOption is the NDP Source Link Layer Option
+// as defined by RFC 4861 section 4.6.1.
+//
+// It is the first X bytes following the NDP option's Type and Length field
+// where X is the value in Length multiplied by lengthByteUnits - 2 bytes.
+type NDPSourceLinkLayerAddressOption tcpip.LinkAddress
+
+// Type implements NDPOption.Type.
+func (o NDPSourceLinkLayerAddressOption) Type() uint8 {
+	return NDPSourceLinkLayerAddressOptionType
+}
+
+// Length implements NDPOption.Length.
+func (o NDPSourceLinkLayerAddressOption) Length() int {
+	return len(o)
+}
+
+// serializeInto implements NDPOption.serializeInto.
+func (o NDPSourceLinkLayerAddressOption) serializeInto(b []byte) int {
+	return copy(b, o)
+}
+
+// String implements fmt.Stringer.String.
+func (o NDPSourceLinkLayerAddressOption) String() string {
+	return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o))
+}
+
+// EthernetAddress will return an ethernet (MAC) address if the
+// NDPSourceLinkLayerAddressOption's body has at minimum EthernetAddressSize
+// bytes. If the body has more than EthernetAddressSize bytes, only the first
+// EthernetAddressSize bytes are returned as that is all that is needed for an
+// Ethernet address.
+func (o NDPSourceLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress {
+	if len(o) >= EthernetAddressSize {
+		return tcpip.LinkAddress(o[:EthernetAddressSize])
+	}
+
+	return tcpip.LinkAddress([]byte(nil))
+}
+
 // NDPTargetLinkLayerAddressOption is the NDP Target Link Layer Option
 // as defined by RFC 4861 section 4.6.1.
 //
@@ -390,6 +440,11 @@ func (o NDPTargetLinkLayerAddressOption) serializeInto(b []byte) int {
 	return copy(b, o)
 }
 
+// String implements fmt.Stringer.String.
+func (o NDPTargetLinkLayerAddressOption) String() string {
+	return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o))
+}
+
 // EthernetAddress will return an ethernet (MAC) address if the
 // NDPTargetLinkLayerAddressOption's body has at minimum EthernetAddressSize
 // bytes. If the body has more than EthernetAddressSize bytes, only the first
@@ -436,6 +491,17 @@ func (o NDPPrefixInformation) serializeInto(b []byte) int {
 	return used
 }
 
+// String implements fmt.Stringer.String.
+func (o NDPPrefixInformation) String() string {
+	return fmt.Sprintf("%T(O=%t, A=%t, PL=%s, VL=%s, Prefix=%s)",
+		o,
+		o.OnLinkFlag(),
+		o.AutonomousAddressConfigurationFlag(),
+		o.PreferredLifetime(),
+		o.ValidLifetime(),
+		o.Subnet())
+}
+
 // PrefixLength returns the value in the number of leading bits in the Prefix
 // that are valid.
 //
@@ -545,6 +611,11 @@ func (o NDPRecursiveDNSServer) serializeInto(b []byte) int {
 	return used
 }
 
+// String implements fmt.Stringer.String.
+func (o NDPRecursiveDNSServer) String() string {
+	return fmt.Sprintf("%T(%s valid for %s)", o, o.Addresses(), o.Lifetime())
+}
+
 // Lifetime returns the length of time that the DNS server addresses
 // in this option may be used for name resolution.
 //