1 files changed, 57 insertions, 0 deletions
diff --git a/dhcpv4/option_maximum_dhcp_message_size.go b/dhcpv4/option_maximum_dhcp_message_size.go
new file mode 100644
index 0000000..05186f5
--- /dev/null
+++ b/dhcpv4/option_maximum_dhcp_message_size.go
@@ -0,0 +1,57 @@
+package dhcpv4
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+// This option implements the Maximum DHCP Message size option
+// https://tools.ietf.org/html/rfc2132
+
+// OptMaximumDHCPMessageSize represents the DHCP message type option.
+type OptMaximumDHCPMessageSize struct {
+	Size uint16
+}
+
+// ParseOptMaximumDHCPMessageSize constructs an OptMaximumDHCPMessageSize struct from a sequence of
+// bytes and returns it, or an error.
+func ParseOptMaximumDHCPMessageSize(data []byte) (*OptMaximumDHCPMessageSize, error) {
+	// Should at least have code, length, and message type.
+	if len(data) < 4 {
+		return nil, ErrShortByteStream
+	}
+	code := OptionCode(data[0])
+	if code != OptionMaximumDHCPMessageSize {
+		return nil, fmt.Errorf("expected option %v, got %v instead", OptionMaximumDHCPMessageSize, code)
+	}
+	length := int(data[1])
+	if length != 2 {
+		return nil, fmt.Errorf("expected length 2, got %v instead", length)
+	}
+	msgSize := binary.BigEndian.Uint16(data[2:4])
+	return &OptMaximumDHCPMessageSize{Size: msgSize}, nil
+}
+
+// Code returns the option code.
+func (o *OptMaximumDHCPMessageSize) Code() OptionCode {
+	return OptionMaximumDHCPMessageSize
+}
+
+// ToBytes returns a serialized stream of bytes for this option.
+func (o *OptMaximumDHCPMessageSize) ToBytes() []byte {
+	serializedSize := make([]byte, 2)
+	binary.BigEndian.PutUint16(serializedSize, o.Size)
+	serializedOpt := []byte{byte(o.Code()), byte(o.Length())}
+	return append(serializedOpt, serializedSize...)
+}
+
+// String returns a human-readable string for this option.
+func (o *OptMaximumDHCPMessageSize) String() string {
+	return fmt.Sprintf("Maximum DHCP Message Size -> %v", o.Size)
+}
+
+// Length returns the length of the data portion (excluding option code and byte
+// for length, if any).
+func (o *OptMaximumDHCPMessageSize) Length() int {
+	return 2
+}