updating github.com/miekg/dns to v1.1.4

vendor/github.com/miekg/dns/defaults.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net"
 	"strconv"
+	"strings"
 )
 
 const hexDigit = "0123456789abcdef"
@@ -13,9 +14,12 @@ const hexDigit = "0123456789abcdef"
 // SetReply creates a reply message from a request message.
 func (dns *Msg) SetReply(request *Msg) *Msg {
 	dns.Id = request.Id
-	dns.RecursionDesired = request.RecursionDesired // Copy rd bit
 	dns.Response = true
-	dns.Opcode = OpcodeQuery
+	dns.Opcode = request.Opcode
+	if dns.Opcode == OpcodeQuery {
+		dns.RecursionDesired = request.RecursionDesired // Copy rd bit
+		dns.CheckingDisabled = request.CheckingDisabled // Copy cd bit
+	}
 	dns.Rcode = RcodeSuccess
 	if len(request.Question) > 0 {
 		dns.Question = make([]Question, 1)
@@ -102,11 +106,11 @@ func (dns *Msg) SetAxfr(z string) *Msg {
 // SetTsig appends a TSIG RR to the message.
 // This is only a skeleton TSIG RR that is added as the last RR in the
 // additional section. The Tsig is calculated when the message is being send.
-func (dns *Msg) SetTsig(z, algo string, fudge, timesigned int64) *Msg {
+func (dns *Msg) SetTsig(z, algo string, fudge uint16, timesigned int64) *Msg {
 	t := new(TSIG)
 	t.Hdr = RR_Header{z, TypeTSIG, ClassANY, 0, 0}
 	t.Algorithm = algo
-	t.Fudge = 300
+	t.Fudge = fudge
 	t.TimeSigned = uint64(timesigned)
 	t.OrigId = dns.Id
 	dns.Extra = append(dns.Extra, t)
@@ -160,11 +164,72 @@ func (dns *Msg) IsEdns0() *OPT {
 // the number of labels.  When false is returned the number of labels is not
 // defined.  Also note that this function is extremely liberal; almost any
 // string is a valid domain name as the DNS is 8 bit protocol. It checks if each
-// label fits in 63 characters, but there is no length check for the entire
-// string s. I.e.  a domain name longer than 255 characters is considered valid.
+// label fits in 63 characters and that the entire name will fit into the 255
+// octet wire format limit.
 func IsDomainName(s string) (labels int, ok bool) {
-	_, labels, err := packDomainName(s, nil, 0, nil, false)
-	return labels, err == nil
+	// XXX: The logic in this function was copied from packDomainName and
+	// should be kept in sync with that function.
+
+	const lenmsg = 256
+
+	if len(s) == 0 { // Ok, for instance when dealing with update RR without any rdata.
+		return 0, false
+	}
+
+	s = Fqdn(s)
+
+	// Each dot ends a segment of the name. Except for escaped dots (\.), which
+	// are normal dots.
+
+	var (
+		off    int
+		begin  int
+		wasDot bool
+	)
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '\\':
+			if off+1 > lenmsg {
+				return labels, false
+			}
+
+			// check for \DDD
+			if i+3 < len(s) && isDigit(s[i+1]) && isDigit(s[i+2]) && isDigit(s[i+3]) {
+				i += 3
+				begin += 3
+			} else {
+				i++
+				begin++
+			}
+
+			wasDot = false
+		case '.':
+			if wasDot {
+				// two dots back to back is not legal
+				return labels, false
+			}
+			wasDot = true
+
+			labelLen := i - begin
+			if labelLen >= 1<<6 { // top two bits of length must be clear
+				return labels, false
+			}
+
+			// off can already (we're in a loop) be bigger than lenmsg
+			// this happens when a name isn't fully qualified
+			off += 1 + labelLen
+			if off > lenmsg {
+				return labels, false
+			}
+
+			labels++
+			begin = i + 1
+		default:
+			wasDot = false
+		}
+	}
+
+	return labels, true
 }
 
 // IsSubDomain checks if child is indeed a child of the parent. If child and parent
@@ -178,7 +243,7 @@ func IsSubDomain(parent, child string) bool {
 // The checking is performed on the binary payload.
 func IsMsg(buf []byte) error {
 	// Header
-	if len(buf) < 12 {
+	if len(buf) < headerSize {
 		return errors.New("dns: bad message header")
 	}
 	// Header: Opcode
@@ -188,11 +253,18 @@ func IsMsg(buf []byte) error {
 
 // IsFqdn checks if a domain name is fully qualified.
 func IsFqdn(s string) bool {
-	l := len(s)
-	if l == 0 {
+	s2 := strings.TrimSuffix(s, ".")
+	if s == s2 {
 		return false
 	}
-	return s[l-1] == '.'
+
+	i := strings.LastIndexFunc(s2, func(r rune) bool {
+		return r != '\\'
+	})
+
+	// Test whether we have an even number of escape sequences before
+	// the dot or none.
+	return (len(s2)-i)%2 != 0
 }
 
 // IsRRset checks if a set of RRs is a valid RRset as defined by RFC 2181.
@@ -241,12 +313,19 @@ func ReverseAddr(addr string) (arpa string, err error) {
 	if ip == nil {
 		return "", &Error{err: "unrecognized address: " + addr}
 	}
-	if ip.To4() != nil {
-		return strconv.Itoa(int(ip[15])) + "." + strconv.Itoa(int(ip[14])) + "." + strconv.Itoa(int(ip[13])) + "." +
-			strconv.Itoa(int(ip[12])) + ".in-addr.arpa.", nil
+	if v4 := ip.To4(); v4 != nil {
+		buf := make([]byte, 0, net.IPv4len*4+len("in-addr.arpa."))
+		// Add it, in reverse, to the buffer
+		for i := len(v4) - 1; i >= 0; i-- {
+			buf = strconv.AppendInt(buf, int64(v4[i]), 10)
+			buf = append(buf, '.')
+		}
+		// Append "in-addr.arpa." and return (buf already has the final .)
+		buf = append(buf, "in-addr.arpa."...)
+		return string(buf), nil
 	}
 	// Must be IPv6
-	buf := make([]byte, 0, len(ip)*4+len("ip6.arpa."))
+	buf := make([]byte, 0, net.IPv6len*4+len("ip6.arpa."))
 	// Add it, in reverse, to the buffer
 	for i := len(ip) - 1; i >= 0; i-- {
 		v := ip[i]
@@ -270,8 +349,11 @@ func (t Type) String() string {
 
 // String returns the string representation for the class c.
 func (c Class) String() string {
-	if c1, ok := ClassToString[uint16(c)]; ok {
-		return c1
+	if s, ok := ClassToString[uint16(c)]; ok {
+		// Only emit mnemonics when they are unambiguous, specically ANY is in both.
+		if _, ok := StringToType[s]; !ok {
+			return s
+		}
 	}
 	return "CLASS" + strconv.Itoa(int(c))
 }