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package dhcpv4
import (
"encoding/binary"
"fmt"
)
// This option implements the IP Address Lease Time option
// https://tools.ietf.org/html/rfc2132
// OptIPAddressLeaseTime represents the IP Address Lease Time option.
type OptIPAddressLeaseTime struct {
LeaseTime uint32
}
// ParseOptIPAddressLeaseTime constructs an OptIPAddressLeaseTime struct from a
// sequence of bytes and returns it, or an error.
func ParseOptIPAddressLeaseTime(data []byte) (*OptIPAddressLeaseTime, error) {
// Should at least have code, length, and lease time.
if len(data) < 6 {
return nil, ErrShortByteStream
}
code := OptionCode(data[0])
if code != OptionIPAddressLeaseTime {
return nil, fmt.Errorf("expected option %v, got %v instead", OptionIPAddressLeaseTime, code)
}
length := int(data[1])
if length != 4 {
return nil, fmt.Errorf("expected length 4, got %v instead", length)
}
leaseTime := binary.BigEndian.Uint32(data[2:6])
return &OptIPAddressLeaseTime{LeaseTime: leaseTime}, nil
}
// Code returns the option code.
func (o *OptIPAddressLeaseTime) Code() OptionCode {
return OptionIPAddressLeaseTime
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptIPAddressLeaseTime) ToBytes() []byte {
serializedTime := make([]byte, 4)
binary.BigEndian.PutUint32(serializedTime, o.LeaseTime)
serializedOpt := []byte{byte(o.Code()), byte(o.Length())}
return append(serializedOpt, serializedTime...)
}
// String returns a human-readable string for this option.
func (o *OptIPAddressLeaseTime) String() string {
return fmt.Sprintf("IP Addresses Lease Time -> %v", o.LeaseTime)
}
// Length returns the length of the data portion (excluding option code and byte
// for length, if any).
func (o *OptIPAddressLeaseTime) Length() int {
return 4
}
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