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package dhcpv4
import (
"errors"
"fmt"
)
// OptionGeneric is an option that only contains the option code and associated
// data. Every option that does not have a specific implementation will fall
// back to this option.
type OptionGeneric struct {
OptionCode OptionCode
Data []byte
}
// ParseOptionGeneric parses a bytestream and creates a new OptionGeneric from
// it, or an error.
func ParseOptionGeneric(data []byte) (*OptionGeneric, error) {
if len(data) == 0 {
return nil, errors.New("invalid zero-length bytestream")
}
var (
length int
optionData []byte
)
code := OptionCode(data[0])
if code != OptionPad && code != OptionEnd {
length = int(data[1])
if len(data) < length+2 {
return nil, fmt.Errorf("invalid data length: declared %v, actual %v", length, len(data))
}
optionData = data[2 : length+2]
}
return &OptionGeneric{OptionCode: code, Data: optionData}, nil
}
// Code returns the generic option code.
func (o OptionGeneric) Code() OptionCode {
return o.OptionCode
}
// ToBytes returns a serialized generic option as a slice of bytes.
func (o OptionGeneric) ToBytes() []byte {
ret := []byte{byte(o.OptionCode)}
if o.OptionCode == OptionEnd || o.OptionCode == OptionPad {
return ret
}
ret = append(ret, byte(o.Length()))
ret = append(ret, o.Data...)
return ret
}
// String returns a human-readable representation of a generic option.
func (o OptionGeneric) String() string {
code, ok := OptionCodeToString[o.OptionCode]
if !ok {
code = "Unknown"
}
return fmt.Sprintf("%v -> %v", code, o.Data)
}
// Length returns the number of bytes comprising the data section of the option.
func (o OptionGeneric) Length() int {
return len(o.Data)
}
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