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package dhcpv6
import (
"fmt"
"net"
"time"
"github.com/u-root/uio/uio"
)
// PrefixOptions are the options valid for use with IAPrefix option field.
//
// RFC 3633 states that it's just the StatusCode option.
//
// RFC 8415 Appendix C does not list the Status Code option as valid, but it
// does say that the previous text in RFC 8415 Section 21.22 supersedes that
// table. Section 21.22 does mention the Status Code option.
type PrefixOptions struct {
Options
}
// Status returns the status code associated with this option.
func (po PrefixOptions) Status() *OptStatusCode {
opt := po.Options.GetOne(OptionStatusCode)
if opt == nil {
return nil
}
sc, ok := opt.(*OptStatusCode)
if !ok {
return nil
}
return sc
}
// OptIAPrefix implements the IAPrefix option.
//
// This module defines the OptIAPrefix structure.
// https://www.ietf.org/rfc/rfc3633.txt
type OptIAPrefix struct {
PreferredLifetime time.Duration
ValidLifetime time.Duration
Prefix *net.IPNet
Options PrefixOptions
}
func (op *OptIAPrefix) Code() OptionCode {
return OptionIAPrefix
}
// ToBytes marshals this option according to RFC 3633, Section 10.
func (op *OptIAPrefix) ToBytes() []byte {
buf := uio.NewBigEndianBuffer(nil)
t1 := Duration{op.PreferredLifetime}
t1.Marshal(buf)
t2 := Duration{op.ValidLifetime}
t2.Marshal(buf)
if op.Prefix != nil {
// Even if Mask is nil, Size will return 0 without panicking.
length, _ := op.Prefix.Mask.Size()
buf.Write8(uint8(length))
write16(buf, op.Prefix.IP)
} else {
buf.Write8(0)
write16(buf, nil)
}
buf.WriteBytes(op.Options.ToBytes())
return buf.Data()
}
func (op *OptIAPrefix) String() string {
return fmt.Sprintf("IAPrefix: {PreferredLifetime=%v, ValidLifetime=%v, Prefix=%s, Options=%v}",
op.PreferredLifetime, op.ValidLifetime, op.Prefix, op.Options)
}
// ParseOptIAPrefix an OptIAPrefix structure from a sequence of bytes. The
// input data does not include option code and length bytes.
func ParseOptIAPrefix(data []byte) (*OptIAPrefix, error) {
buf := uio.NewBigEndianBuffer(data)
var opt OptIAPrefix
var t1, t2 Duration
t1.Unmarshal(buf)
t2.Unmarshal(buf)
opt.PreferredLifetime = t1.Duration
opt.ValidLifetime = t2.Duration
length := buf.Read8()
ip := net.IP(buf.CopyN(net.IPv6len))
if length == 0 {
opt.Prefix = nil
} else {
opt.Prefix = &net.IPNet{
Mask: net.CIDRMask(int(length), 128),
IP: ip,
}
}
if err := opt.Options.FromBytes(buf.ReadAll()); err != nil {
return nil, err
}
return &opt, buf.FinError()
}
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