2010-12-22 20:30:41 +11:00
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package dns
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2010-12-28 00:31:31 +11:00
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import (
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2011-02-25 02:22:14 +11:00
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"encoding/hex"
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2012-06-01 05:40:07 +10:00
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"errors"
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2012-06-01 02:36:27 +10:00
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"net"
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2011-12-10 07:45:57 +11:00
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"strconv"
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2010-12-28 00:31:31 +11:00
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)
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2011-03-25 21:19:35 +11:00
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// EDNS0 Option codes.
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2010-12-22 20:30:41 +11:00
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const (
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_ = iota
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EDNS0LLQ // not used
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EDNS0UL // not used
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EDNS0NSID // NSID, RFC5001
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EDNS0SUBNET = 0x50fa // client-subnet draft
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_DO = 1 << 7 // dnssec ok
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)
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2010-12-28 19:41:54 +11:00
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/*
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* EDNS extended RR.
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* This is the EDNS0 Header
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* Name string "domain-name"
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* Opt uint16 // was type, but is always TypeOPT
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* UDPSize uint16 // was class
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* ExtendedRcode uint8 // was TTL
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* Version uint8 // was TTL
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* Z uint16 // was TTL (all flags should be put here)
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* Rdlength uint16 // length of data after the header
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*/
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2010-12-23 06:53:18 +11:00
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type RR_OPT struct {
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Hdr RR_Header
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Option []EDNS0 `dns:"opt"` // tag is used in Pack and Unpack
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}
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func (rr *RR_OPT) Header() *RR_Header {
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return &rr.Hdr
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}
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func (rr *RR_OPT) String() string {
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s := "\n;; OPT PSEUDOSECTION:\n; EDNS: version " + strconv.Itoa(int(rr.Version())) + "; "
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2011-01-06 20:24:00 +11:00
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if rr.Do() {
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s += "flags: do; "
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} else {
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s += "flags: ; "
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}
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2011-01-07 01:06:06 +11:00
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s += "udp: " + strconv.Itoa(int(rr.UDPSize()))
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2010-12-23 21:02:01 +11:00
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for _, o := range rr.Option {
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switch o.(type) {
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case *EDNS0_NSID:
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s += "\n; NSID: " + o.String()
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h, e := o.Pack()
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var r string
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if e == nil {
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for _, c := range h {
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r += "(" + string(c) + ")"
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}
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s += " " + r
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}
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case *EDNS0_SUBNET:
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s += "\n; SUBNET: " + o.String()
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}
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}
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return s
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}
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2012-01-10 20:43:28 +11:00
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func (rr *RR_OPT) Len() int {
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l := rr.Hdr.Len()
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for i := 0; i < len(rr.Option); i++ {
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lo, _ := rr.Option[i].Pack()
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l += 2 + len(lo)
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}
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return l
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}
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// Version returns the EDNS version.
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func (rr *RR_OPT) Version() uint8 {
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return uint8(rr.Hdr.Ttl & 0x00FF00FFFF)
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}
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// SetVersion sets the version of EDNS. This is usually zero.
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func (rr *RR_OPT) SetVersion(v uint8) {
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rr.Hdr.Ttl = rr.Hdr.Ttl&0xFF00FFFF | uint32(v)
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}
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// UDPSize gets the UDP buffer size.
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func (rr *RR_OPT) UDPSize() uint16 {
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return rr.Hdr.Class
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}
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// SetUDPSize sets the UDP buffer size.
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func (rr *RR_OPT) SetUDPSize(size uint16) {
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rr.Hdr.Class = size
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}
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2010-12-31 04:42:40 +11:00
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/* from RFC 3225
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2011-01-07 00:58:58 +11:00
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+0 (MSB) +1 (LSB)
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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0: | EXTENDED-RCODE | VERSION |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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2: |DO| Z |
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+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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*/
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// Do gets the value of the DO (DNSSEC OK) bit.
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func (rr *RR_OPT) Do() bool {
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return byte(rr.Hdr.Ttl>>8)&_DO == _DO
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}
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2011-09-20 20:52:23 +10:00
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// SetDo sets the DO (DNSSEC OK) bit.
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func (rr *RR_OPT) SetDo() {
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b1 := byte(rr.Hdr.Ttl >> 24)
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b2 := byte(rr.Hdr.Ttl >> 16)
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b3 := byte(rr.Hdr.Ttl >> 8)
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b4 := byte(rr.Hdr.Ttl)
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b3 |= _DO // Set it
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rr.Hdr.Ttl = uint32(b1)<<24 | uint32(b2)<<16 | uint32(b3)<<8 | uint32(b4)
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2010-12-24 00:27:04 +11:00
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}
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2012-06-01 02:36:27 +10:00
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// EDNS0 defines a EDNS0 Option
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type EDNS0 interface {
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// Option return the option code for the option.
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Option() uint16
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// Pack returns the bytes of the option data.
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Pack() ([]byte, error)
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// Unpack sets the data as found in the packet. Is also sets
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// the length of the slice as the length of the option data.
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Unpack([]byte)
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// String returns the string representation of the option.
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String() string
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}
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type EDNS0_NSID struct {
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Code uint16 // Always EDNS0NSID
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Nsid string // This string needs to be hex encoded
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}
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func (e *EDNS0_NSID) Option() uint16 {
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return e.Code
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}
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func (e *EDNS0_NSID) Pack() ([]byte, error) {
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h, err := hex.DecodeString(e.Nsid)
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if err != nil {
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return nil, err
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}
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return h, nil
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}
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2012-06-01 03:33:12 +10:00
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func (e *EDNS0_NSID) Unpack(b []byte) {
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e.Nsid = hex.EncodeToString(b)
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}
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func (e *EDNS0_NSID) String() string {
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return string(e.Nsid)
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}
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type EDNS0_SUBNET struct {
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Code uint16 // Always EDNS0SUBNET
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Family uint16 // 1 for IP, 2 for IP6
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SourceNetmask uint8
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SourceScope uint8
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Address net.IP
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}
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func (e *EDNS0_SUBNET) Option() uint16 {
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return e.Code
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}
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func (e *EDNS0_SUBNET) Pack() ([]byte, error) {
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b := make([]byte, 4)
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b[0], b[1] = packUint16(e.Family)
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b[2] = e.SourceNetmask
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b[3] = e.SourceScope
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switch e.Family {
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case 1:
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// just copy? TODO (also in msg.go...)
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ip := make([]byte, net.IPv4len)
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a := e.Address.To4()
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for i := 0; i < net.IPv4len; i++ {
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if i+1 > len(e.Address) {
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break
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}
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ip[i] = a[i]
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}
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b = append(b, ip...)
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case 2:
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ip := make([]byte, net.IPv6len)
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for i := 0; i < net.IPv6len; i++ {
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if i+1 > len(e.Address) {
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break
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}
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ip[i] = e.Address[i]
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}
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b = append(b, ip...)
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default:
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return nil, errors.New("bad address family")
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}
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return b, nil
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}
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func (e *EDNS0_SUBNET) Unpack(b []byte) {
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// TODO: length of b
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e.Family, _ = unpackUint16(b, 0)
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e.SourceNetmask = b[2]
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e.SourceScope = b[3]
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switch e.Family {
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case 1:
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if len(b) == 8 {
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e.Address = net.IPv4(b[4], b[5], b[6], b[7])
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}
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case 2:
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if len(b) == 20 {
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e.Address = net.IP{b[4], b[4+1], b[4+2], b[4+3], b[4+4],
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b[4+5], b[4+6], b[4+7], b[4+8], b[4+9], b[4+10],
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b[4+11], b[4+12], b[4+13], b[4+14], b[4+15]}
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}
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}
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return
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}
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2012-06-01 07:02:06 +10:00
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func (e *EDNS0_SUBNET) String() (s string) {
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if e.Address.To4() != nil {
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s = e.Address.String()
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} else {
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s = "[" + e.Address.String() + "]"
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}
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s += "/" + strconv.Itoa(int(e.SourceNetmask)) + "/" + strconv.Itoa(int(e.SourceScope))
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return
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2011-01-07 01:24:18 +11:00
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}
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