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package dhcpv6
import (
"fmt"
"strings"
"github.com/u-root/uio/uio"
)
// OptUserClass represent a DHCPv6 User Class option
//
// This module defines the OptUserClass structure.
// https://www.ietf.org/rfc/rfc3315.txt
type OptUserClass struct {
UserClasses [][]byte
}
// Code returns the option code
func (op *OptUserClass) Code() OptionCode {
return OptionUserClass
}
// ToBytes serializes the option and returns it as a sequence of bytes
func (op *OptUserClass) ToBytes() []byte {
buf := uio.NewBigEndianBuffer(nil)
for _, uc := range op.UserClasses {
buf.Write16(uint16(len(uc)))
buf.WriteBytes(uc)
}
return buf.Data()
}
func (op *OptUserClass) String() string {
ucStrings := make([]string, 0, len(op.UserClasses))
for _, uc := range op.UserClasses {
ucStrings = append(ucStrings, string(uc))
}
return fmt.Sprintf("%s: [%s]", op.Code(), strings.Join(ucStrings, ", "))
}
// FromBytes builds an OptUserClass structure from a sequence of bytes. The
// input data does not include option code and length bytes.
func (op *OptUserClass) FromBytes(data []byte) error {
if len(data) == 0 {
return fmt.Errorf("%w: user class option must not be empty", uio.ErrBufferTooShort)
}
buf := uio.NewBigEndianBuffer(data)
for buf.Has(2) {
len := buf.Read16()
op.UserClasses = append(op.UserClasses, buf.CopyN(int(len)))
}
return buf.FinError()
}
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