v6: clean up option NII

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

3 files changed, 58 insertions, 70 deletions

diff --git a/dhcpv6/option_nii.go b/dhcpv6/option_nii.go
index bc47e8c..01d38d4 100644
--- a/dhcpv6/option_nii.go
+++ b/dhcpv6/option_nii.go
@@ -6,17 +6,27 @@ import (
 	"github.com/u-root/u-root/pkg/uio"
 )
 
+// NetworkInterfaceType is the NIC type as defined by RFC 4578 Section 2.2
+type NetworkInterfaceType uint8
+
 // see rfc4578
 const (
-	NII_LANDESK_NOPXE   = 0
-	NII_PXE_GEN_I       = 1
-	NII_PXE_GEN_II      = 2
-	NII_UNDI_NOEFI      = 3
-	NII_UNDI_EFI_GEN_I  = 4
-	NII_UNDI_EFI_GEN_II = 5
+	NII_LANDESK_NOPXE   NetworkInterfaceType = 0
+	NII_PXE_GEN_I       NetworkInterfaceType = 1
+	NII_PXE_GEN_II      NetworkInterfaceType = 2
+	NII_UNDI_NOEFI      NetworkInterfaceType = 3
+	NII_UNDI_EFI_GEN_I  NetworkInterfaceType = 4
+	NII_UNDI_EFI_GEN_II NetworkInterfaceType = 5
 )
 
-var niiToStringMap = map[uint8]string{
+func (nit NetworkInterfaceType) String() string {
+	if s, ok := niiToStringMap[nit]; ok {
+		return s
+	}
+	return fmt.Sprintf("NetworkInterfaceType(%d, unknown)", nit)
+}
+
+var niiToStringMap = map[NetworkInterfaceType]string{
 	NII_LANDESK_NOPXE:   "LANDesk service agent boot ROMs. No PXE",
 	NII_PXE_GEN_I:       "First gen. PXE boot ROMs",
 	NII_PXE_GEN_II:      "Second gen. PXE boot ROMs",
@@ -25,66 +35,39 @@ var niiToStringMap = map[uint8]string{
 	NII_UNDI_EFI_GEN_II: "UNDI 32/64 bit. UEFI runtime 2nd gen",
 }
 
-// OptNetworkInterfaceId implements the NIC ID option for network booting as
+// OptNetworkInterfaceID implements the NIC ID option for network booting as
 // defined by RFC 4578 Section 2.2 and RFC 5970 Section 3.4.
-type OptNetworkInterfaceId struct {
-	type_        uint8
-	major, minor uint8 // revision number
+type OptNetworkInterfaceID struct {
+	Typ NetworkInterfaceType
+
+	// Revision number
+	Major, Minor uint8
 }
 
-func (op *OptNetworkInterfaceId) Code() OptionCode {
+// Code implements Option.Code.
+func (*OptNetworkInterfaceID) Code() OptionCode {
 	return OptionNII
 }
 
-func (op *OptNetworkInterfaceId) ToBytes() []byte {
+// ToBytes implements Option.ToBytes.
+func (op *OptNetworkInterfaceID) ToBytes() []byte {
 	buf := uio.NewBigEndianBuffer(nil)
-	buf.Write8(op.type_)
-	buf.Write8(op.major)
-	buf.Write8(op.minor)
+	buf.Write8(uint8(op.Typ))
+	buf.Write8(op.Major)
+	buf.Write8(op.Minor)
 	return buf.Data()
 }
 
-func (op *OptNetworkInterfaceId) Type() uint8 {
-	return op.type_
-}
-
-func (op *OptNetworkInterfaceId) SetType(type_ uint8) {
-	op.type_ = type_
-}
-
-func (op *OptNetworkInterfaceId) Major() uint8 {
-	return op.major
-}
-
-func (op *OptNetworkInterfaceId) SetMajor(major uint8) {
-	op.major = major
-}
-
-func (op *OptNetworkInterfaceId) Minor() uint8 {
-	return op.minor
-}
-
-func (op *OptNetworkInterfaceId) SetMinor(minor uint8) {
-	op.minor = minor
-}
-
-func (op *OptNetworkInterfaceId) String() string {
-	typeName, ok := niiToStringMap[op.type_]
-	if !ok {
-		typeName = "Unknown"
-	}
-	return fmt.Sprintf("OptNetworkInterfaceId{type=%v, revision=%v.%v}",
-		typeName, op.major, op.minor,
-	)
+func (op *OptNetworkInterfaceID) String() string {
+	return fmt.Sprintf("NetworkInterfaceID: %s (Revision %d.%d)", op.Typ, op.Major, op.Minor)
 }
 
-// build an OptNetworkInterfaceId structure from a sequence of bytes.
-// The input data does not include option code and length bytes.
-func ParseOptNetworkInterfaceId(data []byte) (*OptNetworkInterfaceId, error) {
+// FromBytes builds an OptNetworkInterfaceID structure from a sequence of
+// bytes. The input data does not include option code and length bytes.
+func (op *OptNetworkInterfaceID) FromBytes(data []byte) error {
 	buf := uio.NewBigEndianBuffer(data)
-	var opt OptNetworkInterfaceId
-	opt.type_ = buf.Read8()
-	opt.major = buf.Read8()
-	opt.minor = buf.Read8()
-	return &opt, buf.FinError()
+	op.Typ = NetworkInterfaceType(buf.Read8())
+	op.Major = buf.Read8()
+	op.Minor = buf.Read8()
+	return buf.FinError()
 }
diff --git a/dhcpv6/option_nii_test.go b/dhcpv6/option_nii_test.go
index a355122..6e3170c 100644
--- a/dhcpv6/option_nii_test.go
+++ b/dhcpv6/option_nii_test.go
@@ -12,12 +12,13 @@ func TestOptNetworkInterfaceIdParse(t *testing.T) {
 		3,  // major revision
 		20, // minor revision
 	}
-	opt, err := ParseOptNetworkInterfaceId(expected)
+	var opt OptNetworkInterfaceID
+	err := opt.FromBytes(expected)
 	require.NoError(t, err, "ParseOptNetworkInterfaceId() should not return an error with correct bytes")
 	require.Equal(t, OptionNII, opt.Code(), OptionNII, "Code() should return 62 for OptNetworkInterfaceId")
-	require.Equal(t, uint8(1), opt.Type(), "Type() should return 1 for UNDI")
-	require.Equal(t, uint8(3), opt.Major(), "Major() should return 1 for UNDI")
-	require.Equal(t, uint8(20), opt.Minor(), "Minor() should return 1 for UNDI")
+	require.Equal(t, NetworkInterfaceType(1), opt.Typ, "Typ should return 1 for UNDI")
+	require.Equal(t, uint8(3), opt.Major, "Major should return 1 for UNDI")
+	require.Equal(t, uint8(20), opt.Minor, "Minor should return 1 for UNDI")
 }
 
 func TestOptNetworkInterfaceIdToBytes(t *testing.T) {
@@ -26,10 +27,10 @@ func TestOptNetworkInterfaceIdToBytes(t *testing.T) {
 		3,  // major revision
 		20, // minor revision
 	}
-	opt := OptNetworkInterfaceId{}
-	opt.SetType(1)
-	opt.SetMajor(3)
-	opt.SetMinor(20)
+	var opt OptNetworkInterfaceID
+	opt.Typ = NetworkInterfaceType(1)
+	opt.Major = 3
+	opt.Minor = 20
 	require.Equal(t, expected, opt.ToBytes())
 }
 
@@ -38,7 +39,8 @@ func TestOptNetworkInterfaceIdTooShort(t *testing.T) {
 		1, // type (UNDI)
 		// missing major/minor revision bytes
 	}
-	_, err := ParseOptNetworkInterfaceId(buf)
+	var opt OptNetworkInterfaceID
+	err := opt.FromBytes(buf)
 	require.Error(t, err, "ParseOptNetworkInterfaceId() should return an error on truncated options")
 }
 
@@ -48,18 +50,19 @@ func TestOptNetworkInterfaceIdString(t *testing.T) {
 		3,  // major revision
 		20, // minor revision
 	}
-	opt, err := ParseOptNetworkInterfaceId(buf)
+	var opt OptNetworkInterfaceID
+	err := opt.FromBytes(buf)
 	require.NoError(t, err)
 	require.Contains(
 		t,
 		opt.String(),
-		"type=First gen. PXE boot ROMs, revision=3.20",
+		"First gen. PXE boot ROMs (Revision 3.20)",
 		"String() should contain the type and revision",
 	)
-	opt.SetType(200)
+	opt.Typ = NetworkInterfaceType(200)
 	require.Contains(
 		t, opt.String(),
-		"type=Unknown",
+		"NetworkInterfaceType(200, unknown)",
 		"String() should contain unknown for an unknown type",
 	)
 }
diff --git a/dhcpv6/options.go b/dhcpv6/options.go
index f773c7f..617761f 100644
--- a/dhcpv6/options.go
+++ b/dhcpv6/options.go
@@ -82,7 +82,9 @@ func ParseOption(code OptionCode, optData []byte) (Option, error) {
 	case OptionClientArchType:
 		opt, err = parseOptClientArchType(optData)
 	case OptionNII:
-		opt, err = ParseOptNetworkInterfaceId(optData)
+		var o OptNetworkInterfaceID
+		err = o.FromBytes(optData)
+		opt = &o
 	case Option4RD:
 		opt, err = ParseOpt4RD(optData)
 	case Option4RDMapRule: