| 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} |
| } |