You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: ndp_options.go
    path of file: ./repos/sliver/vendor/gvisor.dev/gvisor/pkg/tcpip/header
    
    the code of the file until where you have to start completion: // Copyright 2019 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package header

import (
	"bytes"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"math"
	"time"

	"gvisor.dev/gvisor/pkg/tcpip"
)

// ndpOptionIdentifier is an NDP option type identifier.
type ndpOptionIdentifier uint8

const (
	// ndpSourceLinkLayerAddressOptionType is the type of the Source Link Layer
	// Address option, as per RFC 4861 section 4.6.1.
	ndpSourceLinkLayerAddressOptionType ndpOptionIdentifier = 1

	// ndpTargetLinkLayerAddressOptionType is the type of the Target Link Layer
	// Address option, as per RFC 4861 section 4.6.1.
	ndpTargetLinkLayerAddress
    
func (o NDPRouteInformation) hasError() error {
	l := len(o)
	if l < ndpRouteInformationRoutePrefixIdx {
		return fmt.Errorf("%T too small, got = %d bytes: %w", o, l, ErrNDPOptMalformedBody)
	}

	prefixLength := int(o.PrefixLength())
	if max := IPv6AddressSize * 8; prefixLength > max {
		return fmt.Errorf("got prefix length = %d, want <= %d: %w", prefixLength, max, ErrNDPOptMalformedBody)
	}

	//   Length      8-bit unsigned integer.  The length of the option
	//               (including the Type and Length fields) in units of 8
	//               octets.  The Length field is 1, 2, or 3 depending on the
	//               Prefix Length.  If Prefix Length is greater than 64, then
	//               Length must be 3.  If Prefix Length is greater than 0,
	//               then Length must be 2 or 3.  If Prefix Length is zero,
	//               then Length must be 1, 2, or 3.
	l += 2 // Add 2 bytes for the type and length bytes.
	lengthField := l / lengthByteUnits
	if prefixLength > 64 {
		if lengthField != 3 {
			return fmt.Errorf("Length field must be 3 when Prefix Length (%d) is > 64 (got = %d): %w", prefixLength, lengthField, ErrNDPOptMalformedBody)
		}
	} else if prefixLength > 0 {
		if lengthField != 2 && lengthField != 3 {
			return fmt.Errorf("Length field must be 2 or 3 when Prefix Length (%d) is between 0 and 64 (got = %d): %w", prefixLength, lengthField, ErrNDPOptMalformedBody)
		}
	} else if lengthField == 0 || lengthField > 3 {
		return fmt.Errorf("Length field must be 1, 2, or 3 when Prefix Length is zero (got = %d): %w", lengthField, ErrNDPOptMalformedBody)
	}

	return nil
}