Merge pull request #15 from jerome-laforge/PR_ORO

RFC 3315: Add OptionRequestOption

miscoptions.go

@@ -9,6 +9,42 @@ import (
 	"time"
 )
 
+// A OptionRequestOption is a list OptionCode, as defined in RFC 3315, Section 22.7.
+//
+// The Option Request option is used to identify a list of options in a
+// message between a client and a server.
+type OptionRequestOption []OptionCode
+
+// MarshalBinary allocates a byte slice containing the data from a OptionRequestOption.
+func (oro OptionRequestOption) MarshalBinary() ([]byte, error) {
+	b := make([]byte, 2*len(oro))
+	for i, j := range oro {
+		binary.BigEndian.PutUint16(b[2*i:], uint16(j))
+	}
+	return b, nil
+}
+
+// UnmarshalBinary unmarshals a raw byte slice into a OptionRequestOption.
+//
+// If the length of byte slice is not be be divisible by 2,
+// errInvalidOptionRequest is returned.
+func (oro *OptionRequestOption) UnmarshalBinary(b []byte) error {
+	// Length must be divisible by 2
+	if len(b)%2 != 0 {
+		return errInvalidOptionRequest
+	}
+
+	// Fill slice by parsing every two bytes using index i.
+	opts := make(OptionRequestOption, len(b)/2)
+	for i := range opts {
+		opts[i] = OptionCode(binary.BigEndian.Uint16(b[2*i:]))
+	}
+
+	*oro = opts
+
+	return nil
+}
+
 // 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

options.go

@@ -212,26 +212,15 @@ func (o Options) IAAddr() ([]*IAAddr, bool, error) {
 // The boolean return value indicates if OptionORO was present in the Options
 // map.  The error return value indicates if a valid OptionCode slice could be
 // parsed from the option.
-func (o Options) OptionRequest() ([]OptionCode, bool, error) {
+func (o Options) OptionRequest() (OptionRequestOption, bool, error) {
 	v, ok := o.Get(OptionORO)
 	if !ok {
 		return nil, false, nil
 	}
 
-	// Length must be divisible by 2
-	if len(v)%2 != 0 {
-		return nil, false, errInvalidOptionRequest
-	}
-
-	// Fill slice by parsing every two bytes using index i,
-	// and using index j to insert options and track number
-	// of iterations until no more options exist
-	opts := make([]OptionCode, len(v)/2, len(v)/2)
-	for i, j := 0, 0; j < len(v)/2; i, j = i+2, j+1 {
-		opts[j] = OptionCode(binary.BigEndian.Uint16(v[i : i+2]))
-	}
-
-	return opts, true, nil
+	var oro OptionRequestOption
+	err := oro.UnmarshalBinary(v)
+	return oro, true, err
 }
 
 // Preference returns the Preference Option value, as described in RFC 3315,

options_test.go

@@ -828,7 +828,7 @@ func TestOptionsOptionRequest(t *testing.T) {
 	var tests = []struct {
 		desc    string
 		options Options
-		codes   []OptionCode
+		codes   OptionRequestOption
 		ok      bool
 		err     error
 	}{