v6: add ClientID getter

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

9 files changed, 55 insertions, 60 deletions

diff --git a/dhcpv6/dhcpv6_test.go b/dhcpv6/dhcpv6_test.go
index b23a858..6f476a1 100644
--- a/dhcpv6/dhcpv6_test.go
+++ b/dhcpv6/dhcpv6_test.go
@@ -165,11 +165,9 @@ func TestNewAdvertiseFromSolicit(t *testing.T) {
 		MessageType:   MessageTypeSolicit,
 		TransactionID: TransactionID{0xa, 0xb, 0xc},
 	}
-	cid := OptClientId{}
-	s.AddOption(&cid)
-	duid := Duid{}
+	s.AddOption(OptClientID(Duid{}))
 
-	a, err := NewAdvertiseFromSolicit(&s, WithServerID(duid))
+	a, err := NewAdvertiseFromSolicit(&s, WithServerID(Duid{}))
 	require.NoError(t, err)
 	require.Equal(t, a.TransactionID, s.TransactionID)
 	require.Equal(t, a.Type(), MessageTypeAdvertise)
@@ -180,11 +178,10 @@ func TestNewReplyFromMessage(t *testing.T) {
 		TransactionID: TransactionID{0xa, 0xb, 0xc},
 		MessageType:   MessageTypeConfirm,
 	}
-	cid := OptClientId{}
-	msg.AddOption(&cid)
+	var duid Duid
+	msg.AddOption(OptClientID(duid))
 	sid := OptServerId{}
-	duid := Duid{}
-	sid.Sid = duid
+	sid.Sid = Duid{}
 	msg.AddOption(&sid)
 
 	rep, err := NewReplyFromMessage(&msg, WithServerID(duid))
@@ -242,11 +239,9 @@ func TestNewMessageTypeSolicit(t *testing.T) {
 
 	require.Equal(t, s.Type(), MessageTypeSolicit)
 	// Check CID
-	cidOption := s.GetOneOption(OptionClientID)
-	require.NotNil(t, cidOption)
-	cid, ok := cidOption.(*OptClientId)
-	require.True(t, ok)
-	require.Equal(t, cid.Cid, duid)
+	cduid := s.Options.ClientID()
+	require.NotNil(t, cduid)
+	require.Equal(t, cduid, &duid)
 
 	// Check ORO
 	oroOption := s.GetOneOption(OptionORO)
diff --git a/dhcpv6/dhcpv6message.go b/dhcpv6/dhcpv6message.go
index d67882a..00452dc 100644
--- a/dhcpv6/dhcpv6message.go
+++ b/dhcpv6/dhcpv6message.go
@@ -29,6 +29,15 @@ func (mo MessageOptions) ArchTypes() iana.Archs {
 	return opt.(*optClientArchType).Archs
 }
 
+// ClientID returns the client identifier option.
+func (mo MessageOptions) ClientID() *Duid {
+	opt := mo.GetOne(OptionClientID)
+	if opt == nil {
+		return nil
+	}
+	return &opt.(*optClientID).Duid
+}
+
 // Message represents a DHCPv6 Message as defined by RFC 3315 Section 6.
 type Message struct {
 	MessageType   MessageType
@@ -72,7 +81,7 @@ func NewSolicit(hwaddr net.HardwareAddr, modifiers ...Modifier) (*Message, error
 		return nil, err
 	}
 	m.MessageType = MessageTypeSolicit
-	m.AddOption(&OptClientId{Cid: duid})
+	m.AddOption(OptClientID(duid))
 	oro := new(OptRequestedOption)
 	oro.SetRequestedOptions([]OptionCode{
 		OptionDNSRecursiveNameServer,
diff --git a/dhcpv6/dhcpv6relay_test.go b/dhcpv6/dhcpv6relay_test.go
index 4070f54..773c047 100644
--- a/dhcpv6/dhcpv6relay_test.go
+++ b/dhcpv6/dhcpv6relay_test.go
@@ -91,7 +91,7 @@ func TestNewRelayRepFromRelayForw(t *testing.T) {
 	// create the inner message
 	s, err := NewMessage()
 	require.NoError(t, err)
-	s.AddOption(&OptClientId{})
+	s.AddOption(OptClientID(Duid{}))
 	orm := OptRelayMsg{}
 	orm.SetRelayMessage(s)
 	rf.AddOption(&orm)
diff --git a/dhcpv6/iputils.go b/dhcpv6/iputils.go
index b8c5876..9c18da2 100644
--- a/dhcpv6/iputils.go
+++ b/dhcpv6/iputils.go
@@ -83,11 +83,10 @@ func ExtractMAC(packet DHCPv6) (net.HardwareAddr, error) {
 			return nil, err
 		}
 	}
-	optclientid := msg.GetOneOption(OptionClientID)
-	if optclientid == nil {
+	duid := msg.(*Message).Options.ClientID()
+	if duid == nil {
 		return nil, fmt.Errorf("client ID not found in packet")
 	}
-	duid := optclientid.(*OptClientId).Cid
 	if duid.LinkLayerAddr == nil {
 		return nil, fmt.Errorf("failed to extract MAC")
 	}
diff --git a/dhcpv6/modifiers.go b/dhcpv6/modifiers.go
index d5e24c0..4d00a0c 100644
--- a/dhcpv6/modifiers.go
+++ b/dhcpv6/modifiers.go
@@ -11,8 +11,7 @@ import (
 // WithClientID adds a client ID option to a DHCPv6 packet
 func WithClientID(duid Duid) Modifier {
 	return func(d DHCPv6) {
-		cid := OptClientId{Cid: duid}
-		d.UpdateOption(&cid)
+		d.UpdateOption(OptClientID(duid))
 	}
 }
 
diff --git a/dhcpv6/modifiers_test.go b/dhcpv6/modifiers_test.go
index ec8ff0b..ff3a87a 100644
--- a/dhcpv6/modifiers_test.go
+++ b/dhcpv6/modifiers_test.go
@@ -17,10 +17,8 @@ func TestWithClientID(t *testing.T) {
 	}
 	m, err := NewMessage(WithClientID(duid))
 	require.NoError(t, err)
-	opt := m.GetOneOption(OptionClientID)
-	require.NotNil(t, opt)
-	cid := opt.(*OptClientId)
-	require.Equal(t, cid.Cid, duid)
+	cid := m.Options.ClientID()
+	require.Equal(t, cid, &duid)
 }
 
 func TestWithServerID(t *testing.T) {
diff --git a/dhcpv6/option_clientid.go b/dhcpv6/option_clientid.go
index 200d1a6..0941bcc 100644
--- a/dhcpv6/option_clientid.go
+++ b/dhcpv6/option_clientid.go
@@ -4,36 +4,31 @@ import (
 	"fmt"
 )
 
-// OptClientId represents a Client ID option
-//
-// This module defines the OptClientId and DUID structures.
-// https://www.ietf.org/rfc/rfc3315.txt
-type OptClientId struct {
-	Cid Duid
+// OptClientID represents a Client Identifier option as defined by RFC 3315
+// Section 22.2.
+func OptClientID(d Duid) Option {
+	return &optClientID{d}
 }
 
-func (op *OptClientId) Code() OptionCode {
-	return OptionClientID
+type optClientID struct {
+	Duid
 }
 
-// ToBytes marshals the Client ID option as defined by RFC 3315, Section 22.2.
-func (op *OptClientId) ToBytes() []byte {
-	return op.Cid.ToBytes()
+func (*optClientID) Code() OptionCode {
+	return OptionClientID
 }
 
-func (op *OptClientId) String() string {
-	return fmt.Sprintf("OptClientId{cid=%v}", op.Cid.String())
+func (op *optClientID) String() string {
+	return fmt.Sprintf("ClientID: %v", op.Duid.String())
 }
 
-// ParseOptClientId builds an OptClientId structure from a sequence
+// parseOptClientID builds an OptClientId structure from a sequence
 // of bytes. The input data does not include option code and length
 // bytes.
-func ParseOptClientId(data []byte) (*OptClientId, error) {
-	var opt OptClientId
+func parseOptClientID(data []byte) (*optClientID, error) {
 	cid, err := DuidFromBytes(data)
 	if err != nil {
 		return nil, err
 	}
-	opt.Cid = *cid
-	return &opt, nil
+	return &optClientID{*cid}, nil
 }
diff --git a/dhcpv6/option_clientid_test.go b/dhcpv6/option_clientid_test.go
index 69a60d1..2f1f1f0 100644
--- a/dhcpv6/option_clientid_test.go
+++ b/dhcpv6/option_clientid_test.go
@@ -8,27 +8,27 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestParseOptClientId(t *testing.T) {
+func TestParseOptClientID(t *testing.T) {
 	data := []byte{
 		0, 3, // DUID_LL
 		0, 1, // hwtype ethernet
 		0, 1, 2, 3, 4, 5, // hw addr
 	}
-	opt, err := ParseOptClientId(data)
+	opt, err := parseOptClientID(data)
 	require.NoError(t, err)
-	require.Equal(t, DUID_LL, opt.Cid.Type)
-	require.Equal(t, iana.HWTypeEthernet, opt.Cid.HwType)
-	require.Equal(t, net.HardwareAddr([]byte{0, 1, 2, 3, 4, 5}), opt.Cid.LinkLayerAddr)
+	require.Equal(t, DUID_LL, opt.Type)
+	require.Equal(t, iana.HWTypeEthernet, opt.HwType)
+	require.Equal(t, net.HardwareAddr([]byte{0, 1, 2, 3, 4, 5}), opt.LinkLayerAddr)
 }
 
 func TestOptClientIdToBytes(t *testing.T) {
-	opt := OptClientId{
-		Cid: Duid{
+	opt := OptClientID(
+		Duid{
 			Type:          DUID_LL,
 			HwType:        iana.HWTypeEthernet,
 			LinkLayerAddr: net.HardwareAddr([]byte{5, 4, 3, 2, 1, 0}),
 		},
-	}
+	)
 	expected := []byte{
 		0, 3, // DUID_LL
 		0, 1, // hwtype ethernet
@@ -43,42 +43,42 @@ func TestOptClientIdDecodeEncode(t *testing.T) {
 		0, 1, // hwtype ethernet
 		5, 4, 3, 2, 1, 0, // hw addr
 	}
-	opt, err := ParseOptClientId(data)
+	opt, err := parseOptClientID(data)
 	require.NoError(t, err)
 	require.Equal(t, data, opt.ToBytes())
 }
 
 func TestOptionClientId(t *testing.T) {
-	opt := OptClientId{
-		Cid: Duid{
+	opt := OptClientID(
+		Duid{
 			Type:          DUID_LL,
 			HwType:        iana.HWTypeEthernet,
 			LinkLayerAddr: net.HardwareAddr([]byte{0xde, 0xad, 0, 0, 0xbe, 0xef}),
 		},
-	}
+	)
 	require.Equal(t, OptionClientID, opt.Code())
 	require.Contains(
 		t,
 		opt.String(),
-		"cid=DUID{type=DUID-LL hwtype=Ethernet hwaddr=de:ad:00:00:be:ef}",
+		"ClientID: DUID{type=DUID-LL hwtype=Ethernet hwaddr=de:ad:00:00:be:ef}",
 		"String() should contain the correct cid output",
 	)
 }
 
-func TestOptClientIdParseOptClientIdBogusDUID(t *testing.T) {
+func TestOptClientIdparseOptClientIDBogusDUID(t *testing.T) {
 	data := []byte{
 		0, 4, // DUID_UUID
 		1, 2, 3, 4, 5, 6, 7, 8, 9, // a UUID should be 18 bytes not 17
 		10, 11, 12, 13, 14, 15, 16, 17,
 	}
-	_, err := ParseOptClientId(data)
+	_, err := parseOptClientID(data)
 	require.Error(t, err, "A truncated OptClientId DUID should return an error")
 }
 
-func TestOptClientIdParseOptClientIdInvalidTooShort(t *testing.T) {
+func TestOptClientIdparseOptClientIDInvalidTooShort(t *testing.T) {
 	data := []byte{
 		0, // truncated: DUIDs are at least 2 bytes
 	}
-	_, err := ParseOptClientId(data)
+	_, err := parseOptClientID(data)
 	require.Error(t, err, "A truncated OptClientId should return an error")
 }
diff --git a/dhcpv6/options.go b/dhcpv6/options.go
index bf37600..ef7c23a 100644
--- a/dhcpv6/options.go
+++ b/dhcpv6/options.go
@@ -40,7 +40,7 @@ func ParseOption(code OptionCode, optData []byte) (Option, error) {
 	)
 	switch code {
 	case OptionClientID:
-		opt, err = ParseOptClientId(optData)
+		opt, err = parseOptClientID(optData)
 	case OptionServerID:
 		opt, err = ParseOptServerId(optData)
 	case OptionIANA: