1 files changed, 39 insertions, 19 deletions
diff --git a/dhcpv4/option_maximum_dhcp_message_size.go b/dhcpv4/option_maximum_dhcp_message_size.go
index 904f3d2..900eea5 100644
--- a/dhcpv4/option_maximum_dhcp_message_size.go
+++ b/dhcpv4/option_maximum_dhcp_message_size.go
@@ -6,32 +6,52 @@ import (
 	"github.com/u-root/u-root/pkg/uio"
 )
 
-// OptMaximumDHCPMessageSize implements the maximum DHCP message size option
-// described by RFC 2132, Section 9.10.
-type OptMaximumDHCPMessageSize struct {
-	Size uint16
+// Uint16 implements encoding and decoding functions for a uint16 as used in
+// RFC 2132, Section 9.10.
+type Uint16 uint16
+
+// ToBytes returns a serialized stream of bytes for this option.
+func (o Uint16) ToBytes() []byte {
+	buf := uio.NewBigEndianBuffer(nil)
+	buf.Write16(uint16(o))
+	return buf.Data()
 }
 
-// ParseOptMaximumDHCPMessageSize constructs an OptMaximumDHCPMessageSize
-// struct from a sequence of bytes and returns it, or an error.
-func ParseOptMaximumDHCPMessageSize(data []byte) (*OptMaximumDHCPMessageSize, error) {
+// String returns a human-readable string for this option.
+func (o Uint16) String() string {
+	return fmt.Sprintf("%d", uint16(o))
+}
+
+// FromBytes decodes data into o as per RFC 2132, Section 9.10.
+func (o *Uint16) FromBytes(data []byte) error {
 	buf := uio.NewBigEndianBuffer(data)
-	return &OptMaximumDHCPMessageSize{Size: buf.Read16()}, buf.FinError()
+	*o = Uint16(buf.Read16())
+	return buf.FinError()
 }
 
-// Code returns the option code.
-func (o *OptMaximumDHCPMessageSize) Code() OptionCode {
-	return OptionMaximumDHCPMessageSize
+// GetUint16 parses a uint16 from code in o.
+func GetUint16(code OptionCode, o Options) (uint16, error) {
+	v := o.Get(code)
+	if v == nil {
+		return 0, fmt.Errorf("option not present")
+	}
+	var u Uint16
+	if err := u.FromBytes(v); err != nil {
+		return 0, err
+	}
+	return uint16(u), nil
 }
 
-// ToBytes returns a serialized stream of bytes for this option.
-func (o *OptMaximumDHCPMessageSize) ToBytes() []byte {
-	buf := uio.NewBigEndianBuffer(nil)
-	buf.Write16(o.Size)
-	return buf.Data()
+// OptMaxMessageSize returns a new DHCP Maximum Message Size option.
+//
+// The Maximum DHCP Message Size option is described by RFC 2132, Section 9.10.
+func OptMaxMessageSize(size uint16) Option {
+	return Option{Code: OptionMaximumDHCPMessageSize, Value: Uint16(size)}
 }
 
-// String returns a human-readable string for this option.
-func (o *OptMaximumDHCPMessageSize) String() string {
-	return fmt.Sprintf("Maximum DHCP Message Size -> %v", o.Size)
+// GetMaxMessageSize returns the DHCP Maximum Message Size in o if present.
+//
+// The Maximum DHCP Message Size option is described by RFC 2132, Section 9.10.
+func GetMaxMessageSize(o Options) (uint16, error) {
+	return GetUint16(OptionMaximumDHCPMessageSize, o)
 }