diff options
Diffstat (limited to 'vendor/github.com/rsc/letsencrypt/vendor/github.com/miekg/dns/msg.go')
| -rw-r--r-- | vendor/github.com/rsc/letsencrypt/vendor/github.com/miekg/dns/msg.go | 1159 |
1 files changed, 0 insertions, 1159 deletions
diff --git a/vendor/github.com/rsc/letsencrypt/vendor/github.com/miekg/dns/msg.go b/vendor/github.com/rsc/letsencrypt/vendor/github.com/miekg/dns/msg.go deleted file mode 100644 index 605fe6c5c..000000000 --- a/vendor/github.com/rsc/letsencrypt/vendor/github.com/miekg/dns/msg.go +++ /dev/null @@ -1,1159 +0,0 @@ -// DNS packet assembly, see RFC 1035. Converting from - Unpack() - -// and to - Pack() - wire format. -// All the packers and unpackers take a (msg []byte, off int) -// and return (off1 int, ok bool). If they return ok==false, they -// also return off1==len(msg), so that the next unpacker will -// also fail. This lets us avoid checks of ok until the end of a -// packing sequence. - -package dns - -//go:generate go run msg_generate.go -//go:generate go run compress_generate.go - -import ( - crand "crypto/rand" - "encoding/binary" - "fmt" - "math/big" - "math/rand" - "strconv" - "sync" -) - -const ( - maxCompressionOffset = 2 << 13 // We have 14 bits for the compression pointer - maxDomainNameWireOctets = 255 // See RFC 1035 section 2.3.4 -) - -var ( - ErrAlg error = &Error{err: "bad algorithm"} // ErrAlg indicates an error with the (DNSSEC) algorithm. - ErrAuth error = &Error{err: "bad authentication"} // ErrAuth indicates an error in the TSIG authentication. - ErrBuf error = &Error{err: "buffer size too small"} // ErrBuf indicates that the buffer used is too small for the message. - ErrConnEmpty error = &Error{err: "conn has no connection"} // ErrConnEmpty indicates a connection is being used before it is initialized. - ErrExtendedRcode error = &Error{err: "bad extended rcode"} // ErrExtendedRcode ... - ErrFqdn error = &Error{err: "domain must be fully qualified"} // ErrFqdn indicates that a domain name does not have a closing dot. - ErrId error = &Error{err: "id mismatch"} // ErrId indicates there is a mismatch with the message's ID. - ErrKeyAlg error = &Error{err: "bad key algorithm"} // ErrKeyAlg indicates that the algorithm in the key is not valid. - ErrKey error = &Error{err: "bad key"} - ErrKeySize error = &Error{err: "bad key size"} - ErrLongDomain error = &Error{err: fmt.Sprintf("domain name exceeded %d wire-format octets", maxDomainNameWireOctets)} - ErrNoSig error = &Error{err: "no signature found"} - ErrPrivKey error = &Error{err: "bad private key"} - ErrRcode error = &Error{err: "bad rcode"} - ErrRdata error = &Error{err: "bad rdata"} - ErrRRset error = &Error{err: "bad rrset"} - ErrSecret error = &Error{err: "no secrets defined"} - ErrShortRead error = &Error{err: "short read"} - ErrSig error = &Error{err: "bad signature"} // ErrSig indicates that a signature can not be cryptographically validated. - ErrSoa error = &Error{err: "no SOA"} // ErrSOA indicates that no SOA RR was seen when doing zone transfers. - ErrTime error = &Error{err: "bad time"} // ErrTime indicates a timing error in TSIG authentication. - ErrTruncated error = &Error{err: "failed to unpack truncated message"} // ErrTruncated indicates that we failed to unpack a truncated message. We unpacked as much as we had so Msg can still be used, if desired. -) - -// Id by default, returns a 16 bits random number to be used as a -// message id. The random provided should be good enough. This being a -// variable the function can be reassigned to a custom function. -// For instance, to make it return a static value: -// -// dns.Id = func() uint16 { return 3 } -var Id func() uint16 = id - -var ( - idLock sync.Mutex - idRand *rand.Rand -) - -// id returns a 16 bits random number to be used as a -// message id. The random provided should be good enough. -func id() uint16 { - idLock.Lock() - - if idRand == nil { - // This (partially) works around - // https://github.com/golang/go/issues/11833 by only - // seeding idRand upon the first call to id. - - var seed int64 - var buf [8]byte - - if _, err := crand.Read(buf[:]); err == nil { - seed = int64(binary.LittleEndian.Uint64(buf[:])) - } else { - seed = rand.Int63() - } - - idRand = rand.New(rand.NewSource(seed)) - } - - // The call to idRand.Uint32 must be within the - // mutex lock because *rand.Rand is not safe for - // concurrent use. - // - // There is no added performance overhead to calling - // idRand.Uint32 inside a mutex lock over just - // calling rand.Uint32 as the global math/rand rng - // is internally protected by a sync.Mutex. - id := uint16(idRand.Uint32()) - - idLock.Unlock() - return id -} - -// MsgHdr is a a manually-unpacked version of (id, bits). -type MsgHdr struct { - Id uint16 - Response bool - Opcode int - Authoritative bool - Truncated bool - RecursionDesired bool - RecursionAvailable bool - Zero bool - AuthenticatedData bool - CheckingDisabled bool - Rcode int -} - -// Msg contains the layout of a DNS message. -type Msg struct { - MsgHdr - Compress bool `json:"-"` // If true, the message will be compressed when converted to wire format. - Question []Question // Holds the RR(s) of the question section. - Answer []RR // Holds the RR(s) of the answer section. - Ns []RR // Holds the RR(s) of the authority section. - Extra []RR // Holds the RR(s) of the additional section. -} - -// ClassToString is a maps Classes to strings for each CLASS wire type. -var ClassToString = map[uint16]string{ - ClassINET: "IN", - ClassCSNET: "CS", - ClassCHAOS: "CH", - ClassHESIOD: "HS", - ClassNONE: "NONE", - ClassANY: "ANY", -} - -// OpcodeToString maps Opcodes to strings. -var OpcodeToString = map[int]string{ - OpcodeQuery: "QUERY", - OpcodeIQuery: "IQUERY", - OpcodeStatus: "STATUS", - OpcodeNotify: "NOTIFY", - OpcodeUpdate: "UPDATE", -} - -// RcodeToString maps Rcodes to strings. -var RcodeToString = map[int]string{ - RcodeSuccess: "NOERROR", - RcodeFormatError: "FORMERR", - RcodeServerFailure: "SERVFAIL", - RcodeNameError: "NXDOMAIN", - RcodeNotImplemented: "NOTIMPL", - RcodeRefused: "REFUSED", - RcodeYXDomain: "YXDOMAIN", // See RFC 2136 - RcodeYXRrset: "YXRRSET", - RcodeNXRrset: "NXRRSET", - RcodeNotAuth: "NOTAUTH", - RcodeNotZone: "NOTZONE", - RcodeBadSig: "BADSIG", // Also known as RcodeBadVers, see RFC 6891 - // RcodeBadVers: "BADVERS", - RcodeBadKey: "BADKEY", - RcodeBadTime: "BADTIME", - RcodeBadMode: "BADMODE", - RcodeBadName: "BADNAME", - RcodeBadAlg: "BADALG", - RcodeBadTrunc: "BADTRUNC", - RcodeBadCookie: "BADCOOKIE", -} - -// Domain names are a sequence of counted strings -// split at the dots. They end with a zero-length string. - -// PackDomainName packs a domain name s into msg[off:]. -// If compression is wanted compress must be true and the compression -// map needs to hold a mapping between domain names and offsets -// pointing into msg. -func PackDomainName(s string, msg []byte, off int, compression map[string]int, compress bool) (off1 int, err error) { - off1, _, err = packDomainName(s, msg, off, compression, compress) - return -} - -func packDomainName(s string, msg []byte, off int, compression map[string]int, compress bool) (off1 int, labels int, err error) { - // special case if msg == nil - lenmsg := 256 - if msg != nil { - lenmsg = len(msg) - } - ls := len(s) - if ls == 0 { // Ok, for instance when dealing with update RR without any rdata. - return off, 0, nil - } - // If not fully qualified, error out, but only if msg == nil #ugly - switch { - case msg == nil: - if s[ls-1] != '.' { - s += "." - ls++ - } - case msg != nil: - if s[ls-1] != '.' { - return lenmsg, 0, ErrFqdn - } - } - // Each dot ends a segment of the name. - // We trade each dot byte for a length byte. - // Except for escaped dots (\.), which are normal dots. - // There is also a trailing zero. - - // Compression - nameoffset := -1 - pointer := -1 - // Emit sequence of counted strings, chopping at dots. - begin := 0 - bs := []byte(s) - roBs, bsFresh, escapedDot := s, true, false - for i := 0; i < ls; i++ { - if bs[i] == '\\' { - for j := i; j < ls-1; j++ { - bs[j] = bs[j+1] - } - ls-- - if off+1 > lenmsg { - return lenmsg, labels, ErrBuf - } - // check for \DDD - if i+2 < ls && isDigit(bs[i]) && isDigit(bs[i+1]) && isDigit(bs[i+2]) { - bs[i] = dddToByte(bs[i:]) - for j := i + 1; j < ls-2; j++ { - bs[j] = bs[j+2] - } - ls -= 2 - } - escapedDot = bs[i] == '.' - bsFresh = false - continue - } - - if bs[i] == '.' { - if i > 0 && bs[i-1] == '.' && !escapedDot { - // two dots back to back is not legal - return lenmsg, labels, ErrRdata - } - if i-begin >= 1<<6 { // top two bits of length must be clear - return lenmsg, labels, ErrRdata - } - // off can already (we're in a loop) be bigger than len(msg) - // this happens when a name isn't fully qualified - if off+1 > lenmsg { - return lenmsg, labels, ErrBuf - } - if msg != nil { - msg[off] = byte(i - begin) - } - offset := off - off++ - for j := begin; j < i; j++ { - if off+1 > lenmsg { - return lenmsg, labels, ErrBuf - } - if msg != nil { - msg[off] = bs[j] - } - off++ - } - if compress && !bsFresh { - roBs = string(bs) - bsFresh = true - } - // Don't try to compress '.' - // We should only compress when compress it true, but we should also still pick - // up names that can be used for *future* compression(s). - if compression != nil && roBs[begin:] != "." { - if p, ok := compression[roBs[begin:]]; !ok { - // Only offsets smaller than this can be used. - if offset < maxCompressionOffset { - compression[roBs[begin:]] = offset - } - } else { - // The first hit is the longest matching dname - // keep the pointer offset we get back and store - // the offset of the current name, because that's - // where we need to insert the pointer later - - // If compress is true, we're allowed to compress this dname - if pointer == -1 && compress { - pointer = p // Where to point to - nameoffset = offset // Where to point from - break - } - } - } - labels++ - begin = i + 1 - } - escapedDot = false - } - // Root label is special - if len(bs) == 1 && bs[0] == '.' { - return off, labels, nil - } - // If we did compression and we find something add the pointer here - if pointer != -1 { - // We have two bytes (14 bits) to put the pointer in - // if msg == nil, we will never do compression - binary.BigEndian.PutUint16(msg[nameoffset:], uint16(pointer^0xC000)) - off = nameoffset + 1 - goto End - } - if msg != nil && off < len(msg) { - msg[off] = 0 - } -End: - off++ - return off, labels, nil -} - -// Unpack a domain name. -// In addition to the simple sequences of counted strings above, -// domain names are allowed to refer to strings elsewhere in the -// packet, to avoid repeating common suffixes when returning -// many entries in a single domain. The pointers are marked -// by a length byte with the top two bits set. Ignoring those -// two bits, that byte and the next give a 14 bit offset from msg[0] -// where we should pick up the trail. -// Note that if we jump elsewhere in the packet, -// we return off1 == the offset after the first pointer we found, -// which is where the next record will start. -// In theory, the pointers are only allowed to jump backward. -// We let them jump anywhere and stop jumping after a while. - -// UnpackDomainName unpacks a domain name into a string. -func UnpackDomainName(msg []byte, off int) (string, int, error) { - s := make([]byte, 0, 64) - off1 := 0 - lenmsg := len(msg) - maxLen := maxDomainNameWireOctets - ptr := 0 // number of pointers followed -Loop: - for { - if off >= lenmsg { - return "", lenmsg, ErrBuf - } - c := int(msg[off]) - off++ - switch c & 0xC0 { - case 0x00: - if c == 0x00 { - // end of name - break Loop - } - // literal string - if off+c > lenmsg { - return "", lenmsg, ErrBuf - } - for j := off; j < off+c; j++ { - switch b := msg[j]; b { - case '.', '(', ')', ';', ' ', '@': - fallthrough - case '"', '\\': - s = append(s, '\\', b) - // presentation-format \X escapes add an extra byte - maxLen += 1 - default: - if b < 32 || b >= 127 { // unprintable, use \DDD - var buf [3]byte - bufs := strconv.AppendInt(buf[:0], int64(b), 10) - s = append(s, '\\') - for i := 0; i < 3-len(bufs); i++ { - s = append(s, '0') - } - for _, r := range bufs { - s = append(s, r) - } - // presentation-format \DDD escapes add 3 extra bytes - maxLen += 3 - } else { - s = append(s, b) - } - } - } - s = append(s, '.') - off += c - case 0xC0: - // pointer to somewhere else in msg. - // remember location after first ptr, - // since that's how many bytes we consumed. - // also, don't follow too many pointers -- - // maybe there's a loop. - if off >= lenmsg { - return "", lenmsg, ErrBuf - } - c1 := msg[off] - off++ - if ptr == 0 { - off1 = off - } - if ptr++; ptr > 10 { - return "", lenmsg, &Error{err: "too many compression pointers"} - } - // pointer should guarantee that it advances and points forwards at least - // but the condition on previous three lines guarantees that it's - // at least loop-free - off = (c^0xC0)<<8 | int(c1) - default: - // 0x80 and 0x40 are reserved - return "", lenmsg, ErrRdata - } - } - if ptr == 0 { - off1 = off - } - if len(s) == 0 { - s = []byte(".") - } else if len(s) >= maxLen { - // error if the name is too long, but don't throw it away - return string(s), lenmsg, ErrLongDomain - } - return string(s), off1, nil -} - -func packTxt(txt []string, msg []byte, offset int, tmp []byte) (int, error) { - if len(txt) == 0 { - if offset >= len(msg) { - return offset, ErrBuf - } - msg[offset] = 0 - return offset, nil - } - var err error - for i := range txt { - if len(txt[i]) > len(tmp) { - return offset, ErrBuf - } - offset, err = packTxtString(txt[i], msg, offset, tmp) - if err != nil { - return offset, err - } - } - return offset, nil -} - -func packTxtString(s string, msg []byte, offset int, tmp []byte) (int, error) { - lenByteOffset := offset - if offset >= len(msg) || len(s) > len(tmp) { - return offset, ErrBuf - } - offset++ - bs := tmp[:len(s)] - copy(bs, s) - for i := 0; i < len(bs); i++ { - if len(msg) <= offset { - return offset, ErrBuf - } - if bs[i] == '\\' { - i++ - if i == len(bs) { - break - } - // check for \DDD - if i+2 < len(bs) && isDigit(bs[i]) && isDigit(bs[i+1]) && isDigit(bs[i+2]) { - msg[offset] = dddToByte(bs[i:]) - i += 2 - } else { - msg[offset] = bs[i] - } - } else { - msg[offset] = bs[i] - } - offset++ - } - l := offset - lenByteOffset - 1 - if l > 255 { - return offset, &Error{err: "string exceeded 255 bytes in txt"} - } - msg[lenByteOffset] = byte(l) - return offset, nil -} - -func packOctetString(s string, msg []byte, offset int, tmp []byte) (int, error) { - if offset >= len(msg) || len(s) > len(tmp) { - return offset, ErrBuf - } - bs := tmp[:len(s)] - copy(bs, s) - for i := 0; i < len(bs); i++ { - if len(msg) <= offset { - return offset, ErrBuf - } - if bs[i] == '\\' { - i++ - if i == len(bs) { - break - } - // check for \DDD - if i+2 < len(bs) && isDigit(bs[i]) && isDigit(bs[i+1]) && isDigit(bs[i+2]) { - msg[offset] = dddToByte(bs[i:]) - i += 2 - } else { - msg[offset] = bs[i] - } - } else { - msg[offset] = bs[i] - } - offset++ - } - return offset, nil -} - -func unpackTxt(msg []byte, off0 int) (ss []string, off int, err error) { - off = off0 - var s string - for off < len(msg) && err == nil { - s, off, err = unpackTxtString(msg, off) - if err == nil { - ss = append(ss, s) - } - } - return -} - -func unpackTxtString(msg []byte, offset int) (string, int, error) { - if offset+1 > len(msg) { - return "", offset, &Error{err: "overflow unpacking txt"} - } - l := int(msg[offset]) - if offset+l+1 > len(msg) { - return "", offset, &Error{err: "overflow unpacking txt"} - } - s := make([]byte, 0, l) - for _, b := range msg[offset+1 : offset+1+l] { - switch b { - case '"', '\\': - s = append(s, '\\', b) - default: - if b < 32 || b > 127 { // unprintable - var buf [3]byte - bufs := strconv.AppendInt(buf[:0], int64(b), 10) - s = append(s, '\\') - for i := 0; i < 3-len(bufs); i++ { - s = append(s, '0') - } - for _, r := range bufs { - s = append(s, r) - } - } else { - s = append(s, b) - } - } - } - offset += 1 + l - return string(s), offset, nil -} - -// Helpers for dealing with escaped bytes -func isDigit(b byte) bool { return b >= '0' && b <= '9' } - -func dddToByte(s []byte) byte { - return byte((s[0]-'0')*100 + (s[1]-'0')*10 + (s[2] - '0')) -} - -// Helper function for packing and unpacking -func intToBytes(i *big.Int, length int) []byte { - buf := i.Bytes() - if len(buf) < length { - b := make([]byte, length) - copy(b[length-len(buf):], buf) - return b - } - return buf -} - -// PackRR packs a resource record rr into msg[off:]. -// See PackDomainName for documentation about the compression. -func PackRR(rr RR, msg []byte, off int, compression map[string]int, compress bool) (off1 int, err error) { - if rr == nil { - return len(msg), &Error{err: "nil rr"} - } - - off1, err = rr.pack(msg, off, compression, compress) - if err != nil { - return len(msg), err - } - // TODO(miek): Not sure if this is needed? If removed we can remove rawmsg.go as well. - if rawSetRdlength(msg, off, off1) { - return off1, nil - } - return off, ErrRdata -} - -// UnpackRR unpacks msg[off:] into an RR. -func UnpackRR(msg []byte, off int) (rr RR, off1 int, err error) { - h, off, msg, err := unpackHeader(msg, off) - if err != nil { - return nil, len(msg), err - } - end := off + int(h.Rdlength) - - if fn, known := typeToUnpack[h.Rrtype]; !known { - rr, off, err = unpackRFC3597(h, msg, off) - } else { - rr, off, err = fn(h, msg, off) - } - if off != end { - return &h, end, &Error{err: "bad rdlength"} - } - return rr, off, err -} - -// unpackRRslice unpacks msg[off:] into an []RR. -// If we cannot unpack the whole array, then it will return nil -func unpackRRslice(l int, msg []byte, off int) (dst1 []RR, off1 int, err error) { - var r RR - // Optimistically make dst be the length that was sent - dst := make([]RR, 0, l) - for i := 0; i < l; i++ { - off1 := off - r, off, err = UnpackRR(msg, off) - if err != nil { - off = len(msg) - break - } - // If offset does not increase anymore, l is a lie - if off1 == off { - l = i - break - } - dst = append(dst, r) - } - if err != nil && off == len(msg) { - dst = nil - } - return dst, off, err -} - -// Convert a MsgHdr to a string, with dig-like headers: -// -//;; opcode: QUERY, status: NOERROR, id: 48404 -// -//;; flags: qr aa rd ra; -func (h *MsgHdr) String() string { - if h == nil { - return "<nil> MsgHdr" - } - - s := ";; opcode: " + OpcodeToString[h.Opcode] - s += ", status: " + RcodeToString[h.Rcode] - s += ", id: " + strconv.Itoa(int(h.Id)) + "\n" - - s += ";; flags:" - if h.Response { - s += " qr" - } - if h.Authoritative { - s += " aa" - } - if h.Truncated { - s += " tc" - } - if h.RecursionDesired { - s += " rd" - } - if h.RecursionAvailable { - s += " ra" - } - if h.Zero { // Hmm - s += " z" - } - if h.AuthenticatedData { - s += " ad" - } - if h.CheckingDisabled { - s += " cd" - } - - s += ";" - return s -} - -// Pack packs a Msg: it is converted to to wire format. -// If the dns.Compress is true the message will be in compressed wire format. -func (dns *Msg) Pack() (msg []byte, err error) { - return dns.PackBuffer(nil) -} - -// PackBuffer packs a Msg, using the given buffer buf. If buf is too small -// a new buffer is allocated. -func (dns *Msg) PackBuffer(buf []byte) (msg []byte, err error) { - // We use a similar function in tsig.go's stripTsig. - var ( - dh Header - compression map[string]int - ) - - if dns.Compress { - compression = make(map[string]int) // Compression pointer mappings - } - - if dns.Rcode < 0 || dns.Rcode > 0xFFF { - return nil, ErrRcode - } - if dns.Rcode > 0xF { - // Regular RCODE field is 4 bits - opt := dns.IsEdns0() - if opt == nil { - return nil, ErrExtendedRcode - } - opt.SetExtendedRcode(uint8(dns.Rcode >> 4)) - dns.Rcode &= 0xF - } - - // Convert convenient Msg into wire-like Header. - dh.Id = dns.Id - dh.Bits = uint16(dns.Opcode)<<11 | uint16(dns.Rcode) - if dns.Response { - dh.Bits |= _QR - } - if dns.Authoritative { - dh.Bits |= _AA - } - if dns.Truncated { - dh.Bits |= _TC - } - if dns.RecursionDesired { - dh.Bits |= _RD - } - if dns.RecursionAvailable { - dh.Bits |= _RA - } - if dns.Zero { - dh.Bits |= _Z - } - if dns.AuthenticatedData { - dh.Bits |= _AD - } - if dns.CheckingDisabled { - dh.Bits |= _CD - } - - // Prepare variable sized arrays. - question := dns.Question - answer := dns.Answer - ns := dns.Ns - extra := dns.Extra - - dh.Qdcount = uint16(len(question)) - dh.Ancount = uint16(len(answer)) - dh.Nscount = uint16(len(ns)) - dh.Arcount = uint16(len(extra)) - - // We need the uncompressed length here, because we first pack it and then compress it. - msg = buf - uncompressedLen := compressedLen(dns, false) - if packLen := uncompressedLen + 1; len(msg) < packLen { - msg = make([]byte, packLen) - } - - // Pack it in: header and then the pieces. - off := 0 - off, err = dh.pack(msg, off, compression, dns.Compress) - if err != nil { - return nil, err - } - for i := 0; i < len(question); i++ { - off, err = question[i].pack(msg, off, compression, dns.Compress) - if err != nil { - return nil, err - } - } - for i := 0; i < len(answer); i++ { - off, err = PackRR(answer[i], msg, off, compression, dns.Compress) - if err != nil { - return nil, err - } - } - for i := 0; i < len(ns); i++ { - off, err = PackRR(ns[i], msg, off, compression, dns.Compress) - if err != nil { - return nil, err - } - } - for i := 0; i < len(extra); i++ { - off, err = PackRR(extra[i], msg, off, compression, dns.Compress) - if err != nil { - return nil, err - } - } - return msg[:off], nil -} - -// Unpack unpacks a binary message to a Msg structure. -func (dns *Msg) Unpack(msg []byte) (err error) { - var ( - dh Header - off int - ) - if dh, off, err = unpackMsgHdr(msg, off); err != nil { - return err - } - - dns.Id = dh.Id - dns.Response = (dh.Bits & _QR) != 0 - dns.Opcode = int(dh.Bits>>11) & 0xF - dns.Authoritative = (dh.Bits & _AA) != 0 - dns.Truncated = (dh.Bits & _TC) != 0 - dns.RecursionDesired = (dh.Bits & _RD) != 0 - dns.RecursionAvailable = (dh.Bits & _RA) != 0 - dns.Zero = (dh.Bits & _Z) != 0 - dns.AuthenticatedData = (dh.Bits & _AD) != 0 - dns.CheckingDisabled = (dh.Bits & _CD) != 0 - dns.Rcode = int(dh.Bits & 0xF) - - if off == len(msg) { - return ErrTruncated - } - - // Optimistically use the count given to us in the header - dns.Question = make([]Question, 0, int(dh.Qdcount)) - - for i := 0; i < int(dh.Qdcount); i++ { - off1 := off - var q Question - q, off, err = unpackQuestion(msg, off) - if err != nil { - // Even if Truncated is set, we only will set ErrTruncated if we - // actually got the questions - return err - } - if off1 == off { // Offset does not increase anymore, dh.Qdcount is a lie! - dh.Qdcount = uint16(i) - break - } - dns.Question = append(dns.Question, q) - } - - dns.Answer, off, err = unpackRRslice(int(dh.Ancount), msg, off) - // The header counts might have been wrong so we need to update it - dh.Ancount = uint16(len(dns.Answer)) - if err == nil { - dns.Ns, off, err = unpackRRslice(int(dh.Nscount), msg, off) - } - // The header counts might have been wrong so we need to update it - dh.Nscount = uint16(len(dns.Ns)) - if err == nil { - dns.Extra, off, err = unpackRRslice(int(dh.Arcount), msg, off) - } - // The header counts might have been wrong so we need to update it - dh.Arcount = uint16(len(dns.Extra)) - - if off != len(msg) { - // TODO(miek) make this an error? - // use PackOpt to let people tell how detailed the error reporting should be? - // println("dns: extra bytes in dns packet", off, "<", len(msg)) - } else if dns.Truncated { - // Whether we ran into a an error or not, we want to return that it - // was truncated - err = ErrTruncated - } - return err -} - -// Convert a complete message to a string with dig-like output. -func (dns *Msg) String() string { - if dns == nil { - return "<nil> MsgHdr" - } - s := dns.MsgHdr.String() + " " - s += "QUERY: " + strconv.Itoa(len(dns.Question)) + ", " - s += "ANSWER: " + strconv.Itoa(len(dns.Answer)) + ", " - s += "AUTHORITY: " + strconv.Itoa(len(dns.Ns)) + ", " - s += "ADDITIONAL: " + strconv.Itoa(len(dns.Extra)) + "\n" - if len(dns.Question) > 0 { - s += "\n;; QUESTION SECTION:\n" - for i := 0; i < len(dns.Question); i++ { - s += dns.Question[i].String() + "\n" - } - } - if len(dns.Answer) > 0 { - s += "\n;; ANSWER SECTION:\n" - for i := 0; i < len(dns.Answer); i++ { - if dns.Answer[i] != nil { - s += dns.Answer[i].String() + "\n" - } - } - } - if len(dns.Ns) > 0 { - s += "\n;; AUTHORITY SECTION:\n" - for i := 0; i < len(dns.Ns); i++ { - if dns.Ns[i] != nil { - s += dns.Ns[i].String() + "\n" - } - } - } - if len(dns.Extra) > 0 { - s += "\n;; ADDITIONAL SECTION:\n" - for i := 0; i < len(dns.Extra); i++ { - if dns.Extra[i] != nil { - s += dns.Extra[i].String() + "\n" - } - } - } - return s -} - -// Len returns the message length when in (un)compressed wire format. -// If dns.Compress is true compression it is taken into account. Len() -// is provided to be a faster way to get the size of the resulting packet, -// than packing it, measuring the size and discarding the buffer. -func (dns *Msg) Len() int { return compressedLen(dns, dns.Compress) } - -// compressedLen returns the message length when in compressed wire format -// when compress is true, otherwise the uncompressed length is returned. -func compressedLen(dns *Msg, compress bool) int { - // We always return one more than needed. - l := 12 // Message header is always 12 bytes - compression := map[string]int{} - - for i := 0; i < len(dns.Question); i++ { - l += dns.Question[i].len() - if compress { - compressionLenHelper(compression, dns.Question[i].Name) - } - } - for i := 0; i < len(dns.Answer); i++ { - if dns.Answer[i] == nil { - continue - } - l += dns.Answer[i].len() - if compress { - k, ok := compressionLenSearch(compression, dns.Answer[i].Header().Name) - if ok { - l += 1 - k - } - compressionLenHelper(compression, dns.Answer[i].Header().Name) - k, ok = compressionLenSearchType(compression, dns.Answer[i]) - if ok { - l += 1 - k - } - compressionLenHelperType(compression, dns.Answer[i]) - } - } - for i := 0; i < len(dns.Ns); i++ { - if dns.Ns[i] == nil { - continue - } - l += dns.Ns[i].len() - if compress { - k, ok := compressionLenSearch(compression, dns.Ns[i].Header().Name) - if ok { - l += 1 - k - } - compressionLenHelper(compression, dns.Ns[i].Header().Name) - k, ok = compressionLenSearchType(compression, dns.Ns[i]) - if ok { - l += 1 - k - } - compressionLenHelperType(compression, dns.Ns[i]) - } - } - for i := 0; i < len(dns.Extra); i++ { - if dns.Extra[i] == nil { - continue - } - l += dns.Extra[i].len() - if compress { - k, ok := compressionLenSearch(compression, dns.Extra[i].Header().Name) - if ok { - l += 1 - k - } - compressionLenHelper(compression, dns.Extra[i].Header().Name) - k, ok = compressionLenSearchType(compression, dns.Extra[i]) - if ok { - l += 1 - k - } - compressionLenHelperType(compression, dns.Extra[i]) - } - } - return l -} - -// Put the parts of the name in the compression map. -func compressionLenHelper(c map[string]int, s string) { - pref := "" - lbs := Split(s) - for j := len(lbs) - 1; j >= 0; j-- { - pref = s[lbs[j]:] - if _, ok := c[pref]; !ok { - c[pref] = len(pref) - } - } -} - -// Look for each part in the compression map and returns its length, -// keep on searching so we get the longest match. -func compressionLenSearch(c map[string]int, s string) (int, bool) { - off := 0 - end := false - if s == "" { // don't bork on bogus data - return 0, false - } - for { - if _, ok := c[s[off:]]; ok { - return len(s[off:]), true - } - if end { - break - } - off, end = NextLabel(s, off) - } - return 0, false -} - -// Copy returns a new RR which is a deep-copy of r. -func Copy(r RR) RR { r1 := r.copy(); return r1 } - -// Len returns the length (in octets) of the uncompressed RR in wire format. -func Len(r RR) int { return r.len() } - -// Copy returns a new *Msg which is a deep-copy of dns. -func (dns *Msg) Copy() *Msg { return dns.CopyTo(new(Msg)) } - -// CopyTo copies the contents to the provided message using a deep-copy and returns the copy. -func (dns *Msg) CopyTo(r1 *Msg) *Msg { - r1.MsgHdr = dns.MsgHdr - r1.Compress = dns.Compress - - if len(dns.Question) > 0 { - r1.Question = make([]Question, len(dns.Question)) - copy(r1.Question, dns.Question) // TODO(miek): Question is an immutable value, ok to do a shallow-copy - } - - rrArr := make([]RR, len(dns.Answer)+len(dns.Ns)+len(dns.Extra)) - var rri int - - if len(dns.Answer) > 0 { - rrbegin := rri - for i := 0; i < len(dns.Answer); i++ { - rrArr[rri] = dns.Answer[i].copy() - rri++ - } - r1.Answer = rrArr[rrbegin:rri:rri] - } - - if len(dns.Ns) > 0 { - rrbegin := rri - for i := 0; i < len(dns.Ns); i++ { - rrArr[rri] = dns.Ns[i].copy() - rri++ - } - r1.Ns = rrArr[rrbegin:rri:rri] - } - - if len(dns.Extra) > 0 { - rrbegin := rri - for i := 0; i < len(dns.Extra); i++ { - rrArr[rri] = dns.Extra[i].copy() - rri++ - } - r1.Extra = rrArr[rrbegin:rri:rri] - } - - return r1 -} - -func (q *Question) pack(msg []byte, off int, compression map[string]int, compress bool) (int, error) { - off, err := PackDomainName(q.Name, msg, off, compression, compress) - if err != nil { - return off, err - } - off, err = packUint16(q.Qtype, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(q.Qclass, msg, off) - if err != nil { - return off, err - } - return off, nil -} - -func unpackQuestion(msg []byte, off int) (Question, int, error) { - var ( - q Question - err error - ) - q.Name, off, err = UnpackDomainName(msg, off) - if err != nil { - return q, off, err - } - if off == len(msg) { - return q, off, nil - } - q.Qtype, off, err = unpackUint16(msg, off) - if err != nil { - return q, off, err - } - if off == len(msg) { - return q, off, nil - } - q.Qclass, off, err = unpackUint16(msg, off) - if off == len(msg) { - return q, off, nil - } - return q, off, err -} - -func (dh *Header) pack(msg []byte, off int, compression map[string]int, compress bool) (int, error) { - off, err := packUint16(dh.Id, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(dh.Bits, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(dh.Qdcount, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(dh.Ancount, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(dh.Nscount, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(dh.Arcount, msg, off) - return off, err -} - -func unpackMsgHdr(msg []byte, off int) (Header, int, error) { - var ( - dh Header - err error - ) - dh.Id, off, err = unpackUint16(msg, off) - if err != nil { - return dh, off, err - } - dh.Bits, off, err = unpackUint16(msg, off) - if err != nil { - return dh, off, err - } - dh.Qdcount, off, err = unpackUint16(msg, off) - if err != nil { - return dh, off, err - } - dh.Ancount, off, err = unpackUint16(msg, off) - if err != nil { - return dh, off, err - } - dh.Nscount, off, err = unpackUint16(msg, off) - if err != nil { - return dh, off, err - } - dh.Arcount, off, err = unpackUint16(msg, off) - return dh, off, err -} |