dns/edns.go

package dns

// Implementation of EDNS0, RFC 2671
const (
        OptionCodeLLQ   = 1
        OptionCodeUL    = 2
        OptionCodeNSID  = 3
        // EDNS flag bits (put in Z section)
        _DO = 1 << 15  // dnssec ok
)

type Option struct {
        Code    uint16
        Data    string "hex"
}

// EDNS extended RR.
// If we are dealing with this, we might copy
// the RR_Header over to this type and allow for
// easy access
type EDNS0_Header struct {
        Name          string "extended-name"
        Opt           uint16 // was type
        UDPSize       uint16 // was class
        ExtendedRcode uint8  // was TTL
        Version       uint8  // was TTL
        Z             uint16 // was TTL (all flags should be put here)
        Rdlength      uint16 // length of data after the header
}

type RR_OPT struct {
        Hdr     RR_Header       // this must become a EDNS0_Header
        Option  []Option "OPT"  // Tag is used in pack and unpack
}

func (rr *RR_OPT) Header() *RR_Header {
        return &rr.Hdr
}

func (rr *RR_OPT) String() string {
        s := rr.Hdr.String()
        for _, o := range rr.Option {
                switch o.Code {
                case OptionCodeNSID:
                        s += "NSID: " + o.Data
                }
        }
        return s
}