diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/edns.go')
| -rw-r--r-- | vendor/github.com/miekg/dns/edns.go | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/vendor/github.com/miekg/dns/edns.go b/vendor/github.com/miekg/dns/edns.go new file mode 100644 index 0000000000..04808d5789 --- /dev/null +++ b/vendor/github.com/miekg/dns/edns.go @@ -0,0 +1,675 @@ +package dns + +import ( + "encoding/binary" + "encoding/hex" + "errors" + "fmt" + "net" + "strconv" +) + +// EDNS0 Option codes. +const ( + EDNS0LLQ = 0x1 // long lived queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01 + EDNS0UL = 0x2 // update lease draft: http://files.dns-sd.org/draft-sekar-dns-ul.txt + EDNS0NSID = 0x3 // nsid (See RFC 5001) + EDNS0DAU = 0x5 // DNSSEC Algorithm Understood + EDNS0DHU = 0x6 // DS Hash Understood + EDNS0N3U = 0x7 // NSEC3 Hash Understood + EDNS0SUBNET = 0x8 // client-subnet (See RFC 7871) + EDNS0EXPIRE = 0x9 // EDNS0 expire + EDNS0COOKIE = 0xa // EDNS0 Cookie + EDNS0TCPKEEPALIVE = 0xb // EDNS0 tcp keep alive (See RFC 7828) + EDNS0PADDING = 0xc // EDNS0 padding (See RFC 7830) + EDNS0LOCALSTART = 0xFDE9 // Beginning of range reserved for local/experimental use (See RFC 6891) + EDNS0LOCALEND = 0xFFFE // End of range reserved for local/experimental use (See RFC 6891) + _DO = 1 << 15 // DNSSEC OK +) + +// OPT is the EDNS0 RR appended to messages to convey extra (meta) information. +// See RFC 6891. +type OPT struct { + Hdr RR_Header + Option []EDNS0 `dns:"opt"` +} + +func (rr *OPT) String() string { + s := "\n;; OPT PSEUDOSECTION:\n; EDNS: version " + strconv.Itoa(int(rr.Version())) + "; " + if rr.Do() { + s += "flags: do; " + } else { + s += "flags: ; " + } + s += "udp: " + strconv.Itoa(int(rr.UDPSize())) + + for _, o := range rr.Option { + switch o.(type) { + case *EDNS0_NSID: + s += "\n; NSID: " + o.String() + h, e := o.pack() + var r string + if e == nil { + for _, c := range h { + r += "(" + string(c) + ")" + } + s += " " + r + } + case *EDNS0_SUBNET: + s += "\n; SUBNET: " + o.String() + case *EDNS0_COOKIE: + s += "\n; COOKIE: " + o.String() + case *EDNS0_UL: + s += "\n; UPDATE LEASE: " + o.String() + case *EDNS0_LLQ: + s += "\n; LONG LIVED QUERIES: " + o.String() + case *EDNS0_DAU: + s += "\n; DNSSEC ALGORITHM UNDERSTOOD: " + o.String() + case *EDNS0_DHU: + s += "\n; DS HASH UNDERSTOOD: " + o.String() + case *EDNS0_N3U: + s += "\n; NSEC3 HASH UNDERSTOOD: " + o.String() + case *EDNS0_LOCAL: + s += "\n; LOCAL OPT: " + o.String() + case *EDNS0_PADDING: + s += "\n; PADDING: " + o.String() + } + } + return s +} + +func (rr *OPT) len(off int, compression map[string]struct{}) int { + l := rr.Hdr.len(off, compression) + for _, o := range rr.Option { + l += 4 // Account for 2-byte option code and 2-byte option length. + lo, _ := o.pack() + l += len(lo) + } + return l +} + +func (rr *OPT) parse(c *zlexer, origin string) *ParseError { + panic("dns: internal error: parse should never be called on OPT") +} + +func (r1 *OPT) isDuplicate(r2 RR) bool { return false } + +// return the old value -> delete SetVersion? + +// Version returns the EDNS version used. Only zero is defined. +func (rr *OPT) Version() uint8 { + return uint8(rr.Hdr.Ttl & 0x00FF0000 >> 16) +} + +// SetVersion sets the version of EDNS. This is usually zero. +func (rr *OPT) SetVersion(v uint8) { + rr.Hdr.Ttl = rr.Hdr.Ttl&0xFF00FFFF | uint32(v)<<16 +} + +// ExtendedRcode returns the EDNS extended RCODE field (the upper 8 bits of the TTL). +func (rr *OPT) ExtendedRcode() int { + return int(rr.Hdr.Ttl&0xFF000000>>24) << 4 +} + +// SetExtendedRcode sets the EDNS extended RCODE field. +// +// If the RCODE is not an extended RCODE, will reset the extended RCODE field to 0. +func (rr *OPT) SetExtendedRcode(v uint16) { + rr.Hdr.Ttl = rr.Hdr.Ttl&0x00FFFFFF | uint32(v>>4)<<24 +} + +// UDPSize returns the UDP buffer size. +func (rr *OPT) UDPSize() uint16 { + return rr.Hdr.Class +} + +// SetUDPSize sets the UDP buffer size. +func (rr *OPT) SetUDPSize(size uint16) { + rr.Hdr.Class = size +} + +// Do returns the value of the DO (DNSSEC OK) bit. +func (rr *OPT) Do() bool { + return rr.Hdr.Ttl&_DO == _DO +} + +// SetDo sets the DO (DNSSEC OK) bit. +// If we pass an argument, set the DO bit to that value. +// It is possible to pass 2 or more arguments. Any arguments after the 1st is silently ignored. +func (rr *OPT) SetDo(do ...bool) { + if len(do) == 1 { + if do[0] { + rr.Hdr.Ttl |= _DO + } else { + rr.Hdr.Ttl &^= _DO + } + } else { + rr.Hdr.Ttl |= _DO + } +} + +// EDNS0 defines an EDNS0 Option. An OPT RR can have multiple options appended to it. +type EDNS0 interface { + // Option returns the option code for the option. + Option() uint16 + // pack returns the bytes of the option data. + pack() ([]byte, error) + // unpack sets the data as found in the buffer. Is also sets + // the length of the slice as the length of the option data. + unpack([]byte) error + // String returns the string representation of the option. + String() string + // copy returns a deep-copy of the option. + copy() EDNS0 +} + +// EDNS0_NSID option is used to retrieve a nameserver +// identifier. When sending a request Nsid must be set to the empty string +// The identifier is an opaque string encoded as hex. +// Basic use pattern for creating an nsid option: +// +// o := new(dns.OPT) +// o.Hdr.Name = "." +// o.Hdr.Rrtype = dns.TypeOPT +// e := new(dns.EDNS0_NSID) +// e.Code = dns.EDNS0NSID +// e.Nsid = "AA" +// o.Option = append(o.Option, e) +type EDNS0_NSID struct { + Code uint16 // Always EDNS0NSID + Nsid string // This string needs to be hex encoded +} + +func (e *EDNS0_NSID) pack() ([]byte, error) { + h, err := hex.DecodeString(e.Nsid) + if err != nil { + return nil, err + } + return h, nil +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_NSID) Option() uint16 { return EDNS0NSID } // Option returns the option code. +func (e *EDNS0_NSID) unpack(b []byte) error { e.Nsid = hex.EncodeToString(b); return nil } +func (e *EDNS0_NSID) String() string { return e.Nsid } +func (e *EDNS0_NSID) copy() EDNS0 { return &EDNS0_NSID{e.Code, e.Nsid} } + +// EDNS0_SUBNET is the subnet option that is used to give the remote nameserver +// an idea of where the client lives. See RFC 7871. It can then give back a different +// answer depending on the location or network topology. +// Basic use pattern for creating an subnet option: +// +// o := new(dns.OPT) +// o.Hdr.Name = "." +// o.Hdr.Rrtype = dns.TypeOPT +// e := new(dns.EDNS0_SUBNET) +// e.Code = dns.EDNS0SUBNET +// e.Family = 1 // 1 for IPv4 source address, 2 for IPv6 +// e.SourceNetmask = 32 // 32 for IPV4, 128 for IPv6 +// e.SourceScope = 0 +// e.Address = net.ParseIP("127.0.0.1").To4() // for IPv4 +// // e.Address = net.ParseIP("2001:7b8:32a::2") // for IPV6 +// o.Option = append(o.Option, e) +// +// This code will parse all the available bits when unpacking (up to optlen). +// When packing it will apply SourceNetmask. If you need more advanced logic, +// patches welcome and good luck. +type EDNS0_SUBNET struct { + Code uint16 // Always EDNS0SUBNET + Family uint16 // 1 for IP, 2 for IP6 + SourceNetmask uint8 + SourceScope uint8 + Address net.IP +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_SUBNET) Option() uint16 { return EDNS0SUBNET } + +func (e *EDNS0_SUBNET) pack() ([]byte, error) { + b := make([]byte, 4) + binary.BigEndian.PutUint16(b[0:], e.Family) + b[2] = e.SourceNetmask + b[3] = e.SourceScope + switch e.Family { + case 0: + // "dig" sets AddressFamily to 0 if SourceNetmask is also 0 + // We might don't need to complain either + if e.SourceNetmask != 0 { + return nil, errors.New("dns: bad address family") + } + case 1: + if e.SourceNetmask > net.IPv4len*8 { + return nil, errors.New("dns: bad netmask") + } + if len(e.Address.To4()) != net.IPv4len { + return nil, errors.New("dns: bad address") + } + ip := e.Address.To4().Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv4len*8)) + needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up + b = append(b, ip[:needLength]...) + case 2: + if e.SourceNetmask > net.IPv6len*8 { + return nil, errors.New("dns: bad netmask") + } + if len(e.Address) != net.IPv6len { + return nil, errors.New("dns: bad address") + } + ip := e.Address.Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv6len*8)) + needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up + b = append(b, ip[:needLength]...) + default: + return nil, errors.New("dns: bad address family") + } + return b, nil +} + +func (e *EDNS0_SUBNET) unpack(b []byte) error { + if len(b) < 4 { + return ErrBuf + } + e.Family = binary.BigEndian.Uint16(b) + e.SourceNetmask = b[2] + e.SourceScope = b[3] + switch e.Family { + case 0: + // "dig" sets AddressFamily to 0 if SourceNetmask is also 0 + // It's okay to accept such a packet + if e.SourceNetmask != 0 { + return errors.New("dns: bad address family") + } + e.Address = net.IPv4(0, 0, 0, 0) + case 1: + if e.SourceNetmask > net.IPv4len*8 || e.SourceScope > net.IPv4len*8 { + return errors.New("dns: bad netmask") + } + addr := make(net.IP, net.IPv4len) + copy(addr, b[4:]) + e.Address = addr.To16() + case 2: + if e.SourceNetmask > net.IPv6len*8 || e.SourceScope > net.IPv6len*8 { + return errors.New("dns: bad netmask") + } + addr := make(net.IP, net.IPv6len) + copy(addr, b[4:]) + e.Address = addr + default: + return errors.New("dns: bad address family") + } + return nil +} + +func (e *EDNS0_SUBNET) String() (s string) { + if e.Address == nil { + s = "<nil>" + } else if e.Address.To4() != nil { + s = e.Address.String() + } else { + s = "[" + e.Address.String() + "]" + } + s += "/" + strconv.Itoa(int(e.SourceNetmask)) + "/" + strconv.Itoa(int(e.SourceScope)) + return +} + +func (e *EDNS0_SUBNET) copy() EDNS0 { + return &EDNS0_SUBNET{ + e.Code, + e.Family, + e.SourceNetmask, + e.SourceScope, + e.Address, + } +} + +// The EDNS0_COOKIE option is used to add a DNS Cookie to a message. +// +// o := new(dns.OPT) +// o.Hdr.Name = "." +// o.Hdr.Rrtype = dns.TypeOPT +// e := new(dns.EDNS0_COOKIE) +// e.Code = dns.EDNS0COOKIE +// e.Cookie = "24a5ac.." +// o.Option = append(o.Option, e) +// +// The Cookie field consists out of a client cookie (RFC 7873 Section 4), that is +// always 8 bytes. It may then optionally be followed by the server cookie. The server +// cookie is of variable length, 8 to a maximum of 32 bytes. In other words: +// +// cCookie := o.Cookie[:16] +// sCookie := o.Cookie[16:] +// +// There is no guarantee that the Cookie string has a specific length. +type EDNS0_COOKIE struct { + Code uint16 // Always EDNS0COOKIE + Cookie string // Hex-encoded cookie data +} + +func (e *EDNS0_COOKIE) pack() ([]byte, error) { + h, err := hex.DecodeString(e.Cookie) + if err != nil { + return nil, err + } + return h, nil +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_COOKIE) Option() uint16 { return EDNS0COOKIE } +func (e *EDNS0_COOKIE) unpack(b []byte) error { e.Cookie = hex.EncodeToString(b); return nil } +func (e *EDNS0_COOKIE) String() string { return e.Cookie } +func (e *EDNS0_COOKIE) copy() EDNS0 { return &EDNS0_COOKIE{e.Code, e.Cookie} } + +// The EDNS0_UL (Update Lease) (draft RFC) option is used to tell the server to set +// an expiration on an update RR. This is helpful for clients that cannot clean +// up after themselves. This is a draft RFC and more information can be found at +// https://tools.ietf.org/html/draft-sekar-dns-ul-02 +// +// o := new(dns.OPT) +// o.Hdr.Name = "." +// o.Hdr.Rrtype = dns.TypeOPT +// e := new(dns.EDNS0_UL) +// e.Code = dns.EDNS0UL +// e.Lease = 120 // in seconds +// o.Option = append(o.Option, e) +type EDNS0_UL struct { + Code uint16 // Always EDNS0UL + Lease uint32 + KeyLease uint32 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_UL) Option() uint16 { return EDNS0UL } +func (e *EDNS0_UL) String() string { return fmt.Sprintf("%d %d", e.Lease, e.KeyLease) } +func (e *EDNS0_UL) copy() EDNS0 { return &EDNS0_UL{e.Code, e.Lease, e.KeyLease} } + +// Copied: http://golang.org/src/pkg/net/dnsmsg.go +func (e *EDNS0_UL) pack() ([]byte, error) { + var b []byte + if e.KeyLease == 0 { + b = make([]byte, 4) + } else { + b = make([]byte, 8) + binary.BigEndian.PutUint32(b[4:], e.KeyLease) + } + binary.BigEndian.PutUint32(b, e.Lease) + return b, nil +} + +func (e *EDNS0_UL) unpack(b []byte) error { + switch len(b) { + case 4: + e.KeyLease = 0 + case 8: + e.KeyLease = binary.BigEndian.Uint32(b[4:]) + default: + return ErrBuf + } + e.Lease = binary.BigEndian.Uint32(b) + return nil +} + +// EDNS0_LLQ stands for Long Lived Queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01 +// Implemented for completeness, as the EDNS0 type code is assigned. +type EDNS0_LLQ struct { + Code uint16 // Always EDNS0LLQ + Version uint16 + Opcode uint16 + Error uint16 + Id uint64 + LeaseLife uint32 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_LLQ) Option() uint16 { return EDNS0LLQ } + +func (e *EDNS0_LLQ) pack() ([]byte, error) { + b := make([]byte, 18) + binary.BigEndian.PutUint16(b[0:], e.Version) + binary.BigEndian.PutUint16(b[2:], e.Opcode) + binary.BigEndian.PutUint16(b[4:], e.Error) + binary.BigEndian.PutUint64(b[6:], e.Id) + binary.BigEndian.PutUint32(b[14:], e.LeaseLife) + return b, nil +} + +func (e *EDNS0_LLQ) unpack(b []byte) error { + if len(b) < 18 { + return ErrBuf + } + e.Version = binary.BigEndian.Uint16(b[0:]) + e.Opcode = binary.BigEndian.Uint16(b[2:]) + e.Error = binary.BigEndian.Uint16(b[4:]) + e.Id = binary.BigEndian.Uint64(b[6:]) + e.LeaseLife = binary.BigEndian.Uint32(b[14:]) + return nil +} + +func (e *EDNS0_LLQ) String() string { + s := strconv.FormatUint(uint64(e.Version), 10) + " " + strconv.FormatUint(uint64(e.Opcode), 10) + + " " + strconv.FormatUint(uint64(e.Error), 10) + " " + strconv.FormatUint(e.Id, 10) + + " " + strconv.FormatUint(uint64(e.LeaseLife), 10) + return s +} +func (e *EDNS0_LLQ) copy() EDNS0 { + return &EDNS0_LLQ{e.Code, e.Version, e.Opcode, e.Error, e.Id, e.LeaseLife} +} + +// EDNS0_DUA implements the EDNS0 "DNSSEC Algorithm Understood" option. See RFC 6975. +type EDNS0_DAU struct { + Code uint16 // Always EDNS0DAU + AlgCode []uint8 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_DAU) Option() uint16 { return EDNS0DAU } +func (e *EDNS0_DAU) pack() ([]byte, error) { return e.AlgCode, nil } +func (e *EDNS0_DAU) unpack(b []byte) error { e.AlgCode = b; return nil } + +func (e *EDNS0_DAU) String() string { + s := "" + for _, alg := range e.AlgCode { + if a, ok := AlgorithmToString[alg]; ok { + s += " " + a + } else { + s += " " + strconv.Itoa(int(alg)) + } + } + return s +} +func (e *EDNS0_DAU) copy() EDNS0 { return &EDNS0_DAU{e.Code, e.AlgCode} } + +// EDNS0_DHU implements the EDNS0 "DS Hash Understood" option. See RFC 6975. +type EDNS0_DHU struct { + Code uint16 // Always EDNS0DHU + AlgCode []uint8 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_DHU) Option() uint16 { return EDNS0DHU } +func (e *EDNS0_DHU) pack() ([]byte, error) { return e.AlgCode, nil } +func (e *EDNS0_DHU) unpack(b []byte) error { e.AlgCode = b; return nil } + +func (e *EDNS0_DHU) String() string { + s := "" + for _, alg := range e.AlgCode { + if a, ok := HashToString[alg]; ok { + s += " " + a + } else { + s += " " + strconv.Itoa(int(alg)) + } + } + return s +} +func (e *EDNS0_DHU) copy() EDNS0 { return &EDNS0_DHU{e.Code, e.AlgCode} } + +// EDNS0_N3U implements the EDNS0 "NSEC3 Hash Understood" option. See RFC 6975. +type EDNS0_N3U struct { + Code uint16 // Always EDNS0N3U + AlgCode []uint8 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_N3U) Option() uint16 { return EDNS0N3U } +func (e *EDNS0_N3U) pack() ([]byte, error) { return e.AlgCode, nil } +func (e *EDNS0_N3U) unpack(b []byte) error { e.AlgCode = b; return nil } + +func (e *EDNS0_N3U) String() string { + // Re-use the hash map + s := "" + for _, alg := range e.AlgCode { + if a, ok := HashToString[alg]; ok { + s += " " + a + } else { + s += " " + strconv.Itoa(int(alg)) + } + } + return s +} +func (e *EDNS0_N3U) copy() EDNS0 { return &EDNS0_N3U{e.Code, e.AlgCode} } + +// EDNS0_EXPIRE implementes the EDNS0 option as described in RFC 7314. +type EDNS0_EXPIRE struct { + Code uint16 // Always EDNS0EXPIRE + Expire uint32 +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_EXPIRE) Option() uint16 { return EDNS0EXPIRE } +func (e *EDNS0_EXPIRE) String() string { return strconv.FormatUint(uint64(e.Expire), 10) } +func (e *EDNS0_EXPIRE) copy() EDNS0 { return &EDNS0_EXPIRE{e.Code, e.Expire} } + +func (e *EDNS0_EXPIRE) pack() ([]byte, error) { + b := make([]byte, 4) + binary.BigEndian.PutUint32(b, e.Expire) + return b, nil +} + +func (e *EDNS0_EXPIRE) unpack(b []byte) error { + if len(b) == 0 { + // zero-length EXPIRE query, see RFC 7314 Section 2 + return nil + } + if len(b) < 4 { + return ErrBuf + } + e.Expire = binary.BigEndian.Uint32(b) + return nil +} + +// The EDNS0_LOCAL option is used for local/experimental purposes. The option +// code is recommended to be within the range [EDNS0LOCALSTART, EDNS0LOCALEND] +// (RFC6891), although any unassigned code can actually be used. The content of +// the option is made available in Data, unaltered. +// Basic use pattern for creating a local option: +// +// o := new(dns.OPT) +// o.Hdr.Name = "." +// o.Hdr.Rrtype = dns.TypeOPT +// e := new(dns.EDNS0_LOCAL) +// e.Code = dns.EDNS0LOCALSTART +// e.Data = []byte{72, 82, 74} +// o.Option = append(o.Option, e) +type EDNS0_LOCAL struct { + Code uint16 + Data []byte +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_LOCAL) Option() uint16 { return e.Code } +func (e *EDNS0_LOCAL) String() string { + return strconv.FormatInt(int64(e.Code), 10) + ":0x" + hex.EncodeToString(e.Data) +} +func (e *EDNS0_LOCAL) copy() EDNS0 { + b := make([]byte, len(e.Data)) + copy(b, e.Data) + return &EDNS0_LOCAL{e.Code, b} +} + +func (e *EDNS0_LOCAL) pack() ([]byte, error) { + b := make([]byte, len(e.Data)) + copied := copy(b, e.Data) + if copied != len(e.Data) { + return nil, ErrBuf + } + return b, nil +} + +func (e *EDNS0_LOCAL) unpack(b []byte) error { + e.Data = make([]byte, len(b)) + copied := copy(e.Data, b) + if copied != len(b) { + return ErrBuf + } + return nil +} + +// EDNS0_TCP_KEEPALIVE is an EDNS0 option that instructs the server to keep +// the TCP connection alive. See RFC 7828. +type EDNS0_TCP_KEEPALIVE struct { + Code uint16 // Always EDNSTCPKEEPALIVE + Length uint16 // the value 0 if the TIMEOUT is omitted, the value 2 if it is present; + Timeout uint16 // an idle timeout value for the TCP connection, specified in units of 100 milliseconds, encoded in network byte order. +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_TCP_KEEPALIVE) Option() uint16 { return EDNS0TCPKEEPALIVE } + +func (e *EDNS0_TCP_KEEPALIVE) pack() ([]byte, error) { + if e.Timeout != 0 && e.Length != 2 { + return nil, errors.New("dns: timeout specified but length is not 2") + } + if e.Timeout == 0 && e.Length != 0 { + return nil, errors.New("dns: timeout not specified but length is not 0") + } + b := make([]byte, 4+e.Length) + binary.BigEndian.PutUint16(b[0:], e.Code) + binary.BigEndian.PutUint16(b[2:], e.Length) + if e.Length == 2 { + binary.BigEndian.PutUint16(b[4:], e.Timeout) + } + return b, nil +} + +func (e *EDNS0_TCP_KEEPALIVE) unpack(b []byte) error { + if len(b) < 4 { + return ErrBuf + } + e.Length = binary.BigEndian.Uint16(b[2:4]) + if e.Length != 0 && e.Length != 2 { + return errors.New("dns: length mismatch, want 0/2 but got " + strconv.FormatUint(uint64(e.Length), 10)) + } + if e.Length == 2 { + if len(b) < 6 { + return ErrBuf + } + e.Timeout = binary.BigEndian.Uint16(b[4:6]) + } + return nil +} + +func (e *EDNS0_TCP_KEEPALIVE) String() (s string) { + s = "use tcp keep-alive" + if e.Length == 0 { + s += ", timeout omitted" + } else { + s += fmt.Sprintf(", timeout %dms", e.Timeout*100) + } + return +} +func (e *EDNS0_TCP_KEEPALIVE) copy() EDNS0 { return &EDNS0_TCP_KEEPALIVE{e.Code, e.Length, e.Timeout} } + +// EDNS0_PADDING option is used to add padding to a request/response. The default +// value of padding SHOULD be 0x0 but other values MAY be used, for instance if +// compression is applied before encryption which may break signatures. +type EDNS0_PADDING struct { + Padding []byte +} + +// Option implements the EDNS0 interface. +func (e *EDNS0_PADDING) Option() uint16 { return EDNS0PADDING } +func (e *EDNS0_PADDING) pack() ([]byte, error) { return e.Padding, nil } +func (e *EDNS0_PADDING) unpack(b []byte) error { e.Padding = b; return nil } +func (e *EDNS0_PADDING) String() string { return fmt.Sprintf("%0X", e.Padding) } +func (e *EDNS0_PADDING) copy() EDNS0 { + b := make([]byte, len(e.Padding)) + copy(b, e.Padding) + return &EDNS0_PADDING{b} +} |