miscoptions: add miscellaneous options file, add Preference type, upd…

…ate tests

miscoptions.go

@@ -0,0 +1,29 @@
+package dhcp6
+
+import (
+	"io"
+)
+
+// A Preference is a preference value, as defined in RFC 3315, Section 22.8.
+//
+// A preference value is sent by a server to a client to affect the selection
+// of a server by the client.
+type Preference uint8
+
+// MarshalBinary allocates a byte slice containing the data from a Preference.
+func (p Preference) MarshalBinary() ([]byte, error) {
+	return []byte{byte(p)}, nil
+}
+
+// UnmarshalBinary unmarshals a raw byte slice into a Preference.
+//
+// If the byte slice is not exactly 1 byte in length, io.ErrUnexpectedEOF is
+// returned.
+func (p *Preference) UnmarshalBinary(b []byte) error {
+	if len(b) != 1 {
+		return io.ErrUnexpectedEOF
+	}
+
+	*p = Preference(b[0])
+	return nil
+}

options.go

@@ -29,10 +29,6 @@ var (
 	// from OptionOptionRequest, because an odd number of bytes are present.
 	errInvalidOptionRequest = errors.New("invalid option value for OptionRequestOption")
 
-	// errInvalidPreference is returned when a valid integer cannot be parsed
-	// from OptionPreference, because more or less than one byte are present.
-	errInvalidPreference = errors.New("invalid option value for OptionPreference")
-
 	// errInvalidRapidCommit is returned when OptionRapidCommit contains any
 	// amount of additional data, since it should be completely empty.
 	errInvalidRapidCommit = errors.New("invalid option value for OptionRapidCommit")
@@ -263,18 +259,15 @@ func (o Options) OptionRequest() ([]OptionCode, bool, error) {
 // The boolean return value indicates if OptionPreference was present in the
 // Options map.  The error return value indicates if a valid integer value
 // could not be parsed from the option.
-func (o Options) Preference() (uint8, bool, error) {
+func (o Options) Preference() (Preference, bool, error) {
 	v, ok := o.Get(OptionPreference)
 	if !ok {
 		return 0, false, nil
 	}
 
-	// Length must be exactly 1
-	if len(v) != 1 {
-		return 0, false, errInvalidPreference
-	}
-
-	return uint8(v[0]), true, nil
+	p := new(Preference)
+	err := p.UnmarshalBinary(v)
+	return *p, true, err
 }
 
 // ElapsedTime returns the Elapsed Time Option value, as described in RFC 3315,

options_test.go

@@ -3,6 +3,7 @@ package dhcp6
 import (
 	"bytes"
 	"encoding"
+	"io"
 	"net"
 	"net/url"
 	"reflect"
@@ -135,6 +136,14 @@ func TestOptionsAddBinaryMarshaler(t *testing.T) {
 				}},
 			},
 		},
+		{
+			desc: "Preference",
+			code: OptionPreference,
+			bin:  Preference(255),
+			options: Options{
+				OptionPreference: [][]byte{{255}},
+			},
+		},
 		{
 			desc: "StatusCode",
 			code: OptionStatusCode,
@@ -801,7 +810,7 @@ func TestOptionsPreference(t *testing.T) {
 	var tests = []struct {
 		desc       string
 		options    Options
-		preference uint8
+		preference Preference
 		ok         bool
 		err        error
 	}{
@@ -813,14 +822,14 @@ func TestOptionsPreference(t *testing.T) {
 			options: Options{
 				OptionPreference: [][]byte{{}},
 			},
-			err: errInvalidPreference,
+			err: io.ErrUnexpectedEOF,
 		},
 		{
 			desc: "OptionPreference present in Options map, but too long length",
 			options: Options{
 				OptionPreference: [][]byte{{0, 1}},
 			},
-			err: errInvalidPreference,
+			err: io.ErrUnexpectedEOF,
 		},
 		{
 			desc: "OptionPreference present in Options map",

server_test.go

@@ -288,7 +288,7 @@ func TestServeOK(t *testing.T) {
 	r.b.Write(pb)
 
 	// Expect these option values set by server
-	var preference uint8 = 255
+	var preference Preference = 255
 	sCode := StatusSuccess
 	sMsg := "success"