dhcpv6 DUID: re-add Equal function

Signed-off-by: Chris Koch <chrisko@google.com>

2 files changed, 136 insertions, 0 deletions

diff --git a/dhcpv6/duid.go b/dhcpv6/duid.go
index fcd785d..027c6b0 100644
--- a/dhcpv6/duid.go
+++ b/dhcpv6/duid.go
@@ -1,6 +1,7 @@
 package dhcpv6
 
 import (
+	"bytes"
 	"fmt"
 	"net"
 
@@ -15,6 +16,7 @@ type DUID interface {
 	ToBytes() []byte
 	FromBytes(p []byte) error
 	DUIDType() DUIDType
+	Equal(d DUID) bool
 }
 
 // DUIDLLT is a DUID based on link-layer address plus time (RFC 8415 Section 11.2).
@@ -53,6 +55,15 @@ func (d *DUIDLLT) FromBytes(p []byte) error {
 	return buf.FinError()
 }
 
+// Equal returns true if e is a DUID-LLT with the same values as d.
+func (d *DUIDLLT) Equal(e DUID) bool {
+	ellt, ok := e.(*DUIDLLT)
+	if !ok {
+		return false
+	}
+	return d.HWType == ellt.HWType && d.Time == ellt.Time && bytes.Equal(d.LinkLayerAddr, ellt.LinkLayerAddr)
+}
+
 // DUIDLL is a DUID based on link-layer (RFC 8415 Section 11.4).
 type DUIDLL struct {
 	HWType        iana.HWType
@@ -86,6 +97,15 @@ func (d *DUIDLL) FromBytes(p []byte) error {
 	return buf.FinError()
 }
 
+// Equal returns true if e is a DUID-LL with the same values as d.
+func (d *DUIDLL) Equal(e DUID) bool {
+	ell, ok := e.(*DUIDLL)
+	if !ok {
+		return false
+	}
+	return d.HWType == ell.HWType && bytes.Equal(d.LinkLayerAddr, ell.LinkLayerAddr)
+}
+
 // DUIDEN is a DUID based on enterprise number (RFC 8415 Section 11.3).
 type DUIDEN struct {
 	EnterpriseNumber     uint32
@@ -119,6 +139,15 @@ func (d *DUIDEN) FromBytes(p []byte) error {
 	return buf.FinError()
 }
 
+// Equal returns true if e is a DUID-EN with the same values as d.
+func (d *DUIDEN) Equal(e DUID) bool {
+	en, ok := e.(*DUIDEN)
+	if !ok {
+		return false
+	}
+	return d.EnterpriseNumber == en.EnterpriseNumber && bytes.Equal(d.EnterpriseIdentifier, en.EnterpriseIdentifier)
+}
+
 // DUIDUUID is a DUID based on UUID (RFC 8415 Section 11.5).
 type DUIDUUID struct {
 	// Defined by RFC 6355.
@@ -191,6 +220,15 @@ func (d *DUIDOpaque) FromBytes(p []byte) error {
 	return nil
 }
 
+// Equal returns true if e is an opaque DUID with the same values as d.
+func (d *DUIDOpaque) Equal(e DUID) bool {
+	eopaque, ok := e.(*DUIDOpaque)
+	if !ok {
+		return false
+	}
+	return d.Type == eopaque.Type && bytes.Equal(d.Data, eopaque.Data)
+}
+
 // DUIDType is the DUID type as defined in RFC 3315.
 type DUIDType uint16
 
diff --git a/dhcpv6/duid_test.go b/dhcpv6/duid_test.go
index d035474..7174dc5 100644
--- a/dhcpv6/duid_test.go
+++ b/dhcpv6/duid_test.go
@@ -136,3 +136,101 @@ func TestFromBytes(t *testing.T) {
 		})
 	}
 }
+
+func TestEqual(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		a    DUID
+		b    DUID
+		want bool
+	}{
+		{
+			name: "DUID-LL-equal",
+			a:    &DUIDLL{HWType: iana.HWTypeEthernet, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDLL{HWType: iana.HWTypeEthernet, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			want: true,
+		},
+		{
+			name: "DUID-LL-not-equal",
+			a:    &DUIDLL{HWType: iana.HWTypeEthernet, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDLL{HWType: iana.HWTypeEthernet, LinkLayerAddr: net.HardwareAddr{0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa}},
+			want: false,
+		},
+		{
+			name: "DUID-LL-and-DUID-EN",
+			a:    &DUIDLL{HWType: iana.HWTypeEthernet, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDEN{EnterpriseNumber: 5, EnterpriseIdentifier: []byte("foo")},
+			want: false,
+		},
+		{
+			name: "DUID-EN-equal",
+			a:    &DUIDEN{EnterpriseNumber: 5, EnterpriseIdentifier: []byte("foo")},
+			b:    &DUIDEN{EnterpriseNumber: 5, EnterpriseIdentifier: []byte("foo")},
+			want: true,
+		},
+		{
+			name: "DUID-EN-not-equal",
+			a:    &DUIDEN{EnterpriseNumber: 5, EnterpriseIdentifier: []byte("foo")},
+			b:    &DUIDEN{EnterpriseNumber: 5, EnterpriseIdentifier: []byte("bar")},
+			want: false,
+		},
+		{
+			name: "DUID-LLT-equal",
+			a:    &DUIDLLT{HWType: iana.HWTypeEthernet, Time: 10, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDLLT{HWType: iana.HWTypeEthernet, Time: 10, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			want: true,
+		},
+		{
+			name: "DUID-LLT-not-equal",
+			a:    &DUIDLLT{HWType: iana.HWTypeEthernet, Time: 10, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDLLT{HWType: iana.HWTypeEthernet, Time: 10, LinkLayerAddr: net.HardwareAddr{0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa}},
+			want: false,
+		},
+		{
+			name: "DUID-LLT-and-DUID-UUID",
+			a:    &DUIDLLT{HWType: iana.HWTypeEthernet, Time: 10, LinkLayerAddr: net.HardwareAddr{0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}},
+			b:    &DUIDUUID{UUID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04}},
+			want: false,
+		},
+		{
+			name: "DUID-UUID-equal",
+			a:    &DUIDUUID{UUID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04}},
+			b:    &DUIDUUID{UUID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04}},
+			want: true,
+		},
+		{
+			name: "DUID-UUID-not-equal",
+			a:    &DUIDUUID{UUID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04}},
+			b:    &DUIDUUID{UUID: [16]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}},
+			want: false,
+		},
+		{
+			name: "DUID-UUID-and-DUID-Opaque",
+			a:    &DUIDOpaque{Type: 5, Data: []byte{0x1}},
+			b:    &DUIDUUID{UUID: [16]byte{0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04, 0x01, 0x02, 0x03, 0x04}},
+			want: false,
+		},
+		{
+			name: "DUID-Opaque-equal",
+			a:    &DUIDOpaque{Type: 5, Data: []byte{0x1}},
+			b:    &DUIDOpaque{Type: 5, Data: []byte{0x1}},
+			want: true,
+		},
+		{
+			name: "DUID-Opaque-not-equal",
+			a:    &DUIDOpaque{Type: 5, Data: []byte{0x1}},
+			b:    &DUIDOpaque{Type: 5, Data: []byte{0x2}},
+			want: false,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.a.Equal(tt.b); got != tt.want {
+				t.Errorf("%s.Equal(%s) = %v, want %v", tt.a, tt.b, got, tt.want)
+			}
+
+			if got := tt.b.Equal(tt.a); got != tt.want {
+				t.Errorf("%s.Equal(%s) = %v, want %v", tt.b, tt.a, got, tt.want)
+			}
+		})
+	}
+}