.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/go.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: [ 1.19.x, 1.20.x ]
+        go: [ 1.20.x, 1.21.x ]
     steps:
 
     - name: Set up Go

acceptfunc.go

@@ -10,8 +10,6 @@ type MsgAcceptFunc func(dh Header) MsgAcceptAction
 //
 // * opcode isn't OpcodeQuery or OpcodeNotify
 //
-// * Zero bit isn't zero
-//
 // * does not have exactly 1 question in the question section
 //
 // * has more than 1 RR in the Answer section

defaults.go

@@ -5,7 +5,6 @@ import (
 	"net"
 	"strconv"
 	"strings"
-	"unicode"
 )
 
 const hexDigit = "0123456789abcdef"
@@ -23,8 +22,7 @@ func (dns *Msg) SetReply(request *Msg) *Msg {
 	}
 	dns.Rcode = RcodeSuccess
 	if len(request.Question) > 0 {
-		dns.Question = make([]Question, 1)
-		dns.Question[0] = request.Question[0]
+		dns.Question = []Question{request.Question[0]}
 	}
 	return dns
 }
@@ -293,26 +291,19 @@ func IsFqdn(s string) bool {
 	return (len(s)-i)%2 != 0
 }
 
-// IsRRset checks if a set of RRs is a valid RRset as defined by RFC 2181.
-// This means the RRs need to have the same type, name, and class. Returns true
-// if the RR set is valid, otherwise false.
+// IsRRset reports whether a set of RRs is a valid RRset as defined by RFC 2181.
+// This means the RRs need to have the same type, name, and class.
 func IsRRset(rrset []RR) bool {
 	if len(rrset) == 0 {
 		return false
 	}
-	if len(rrset) == 1 {
-		return true
-	}
-	rrHeader := rrset[0].Header()
-	rrType := rrHeader.Rrtype
-	rrClass := rrHeader.Class
-	rrName := rrHeader.Name
 
+	baseH := rrset[0].Header()
 	for _, rr := range rrset[1:] {
-		curRRHeader := rr.Header()
-		if curRRHeader.Rrtype != rrType || curRRHeader.Class != rrClass || curRRHeader.Name != rrName {
+		curH := rr.Header()
+		if curH.Rrtype != baseH.Rrtype || curH.Class != baseH.Class || curH.Name != baseH.Name {
 			// Mismatch between the records, so this is not a valid rrset for
-			//signing/verifying
+			// signing/verifying
 			return false
 		}
 	}
@@ -330,19 +321,15 @@ func Fqdn(s string) string {
 }
 
 // CanonicalName returns the domain name in canonical form. A name in canonical
-// form is lowercase and fully qualified. See Section 6.2 in RFC 4034.
-// According to the RFC all uppercase US-ASCII letters in the owner name of the
-// RR areeplaced by the corresponding lowercase US-ASCII letters.
+// form is lowercase and fully qualified. Only US-ASCII letters are affected. See
+// Section 6.2 in RFC 4034.
 func CanonicalName(s string) string {
-	var result strings.Builder
-	for _, ch := range s {
-		if unicode.IsUpper(ch) && (ch >= 0x00 && ch <= 0x7F) {
-			result.WriteRune(unicode.ToLower(ch))
-		} else {
-			result.WriteRune(ch)
+	return strings.Map(func(r rune) rune {
+		if r >= 'A' && r <= 'Z' {
+			r += 'a' - 'A'
 		}
-	}
-	return Fqdn(result.String())
+		return r
+	}, Fqdn(s))
 }
 
 // Copied from the official Go code.

dnssec_keyscan.go

@@ -37,7 +37,8 @@ func (k *DNSKEY) ReadPrivateKey(q io.Reader, file string) (crypto.PrivateKey, er
 		return nil, ErrPrivKey
 	}
 	// TODO(mg): check if the pubkey matches the private key
-	algo, err := strconv.ParseUint(strings.SplitN(m["algorithm"], " ", 2)[0], 10, 8)
+	algoStr, _, _ := strings.Cut(m["algorithm"], " ")
+	algo, err := strconv.ParseUint(algoStr, 10, 8)
 	if err != nil {
 		return nil, ErrPrivKey
 	}

edns.go

@@ -185,7 +185,7 @@ func (rr *OPT) Do() bool {
 
 // 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.
+// It is possible to pass 2 or more arguments, but they will be ignored.
 func (rr *OPT) SetDo(do ...bool) {
 	if len(do) == 1 {
 		if do[0] {
@@ -508,6 +508,7 @@ func (e *EDNS0_LLQ) String() string {
 		" " + 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}
 }

generate.go

@@ -35,17 +35,17 @@ func (zp *ZoneParser) generate(l lex) (RR, bool) {
 		token = token[:i]
 	}
 
-	sx := strings.SplitN(token, "-", 2)
-	if len(sx) != 2 {
+	startStr, endStr, ok := strings.Cut(token, "-")
+	if !ok {
 		return zp.setParseError("bad start-stop in $GENERATE range", l)
 	}
 
-	start, err := strconv.ParseInt(sx[0], 10, 64)
+	start, err := strconv.ParseInt(startStr, 10, 64)
 	if err != nil {
 		return zp.setParseError("bad start in $GENERATE range", l)
 	}
 
-	end, err := strconv.ParseInt(sx[1], 10, 64)
+	end, err := strconv.ParseInt(endStr, 10, 64)
 	if err != nil {
 		return zp.setParseError("bad stop in $GENERATE range", l)
 	}
@@ -54,7 +54,7 @@ func (zp *ZoneParser) generate(l lex) (RR, bool) {
 	}
 
 	// _BLANK
-	l, ok := zp.c.Next()
+	l, ok = zp.c.Next()
 	if !ok || l.value != zBlank {
 		return zp.setParseError("garbage after $GENERATE range", l)
 	}
@@ -211,15 +211,16 @@ func (r *generateReader) ReadByte() (byte, error) {
 func modToPrintf(s string) (string, int64, string) {
 	// Modifier is { offset [ ,width [ ,base ] ] } - provide default
 	// values for optional width and type, if necessary.
-	var offStr, widthStr, base string
-	switch xs := strings.Split(s, ","); len(xs) {
-	case 1:
-		offStr, widthStr, base = xs[0], "0", "d"
-	case 2:
-		offStr, widthStr, base = xs[0], xs[1], "d"
-	case 3:
-		offStr, widthStr, base = xs[0], xs[1], xs[2]
-	default:
+	offStr, s, ok0 := strings.Cut(s, ",")
+	widthStr, s, ok1 := strings.Cut(s, ",")
+	base, _, ok2 := strings.Cut(s, ",")
+	if !ok0 {
+		widthStr = "0"
+	}
+	if !ok1 {
+		base = "d"
+	}
+	if ok2 {
 		return "", 0, "bad modifier in $GENERATE"
 	}
 
@@ -234,8 +235,8 @@ func modToPrintf(s string) (string, int64, string) {
 		return "", 0, "bad offset in $GENERATE"
 	}
 
-	width, err := strconv.ParseInt(widthStr, 10, 64)
-	if err != nil || width < 0 || width > 255 {
+	width, err := strconv.ParseUint(widthStr, 10, 8)
+	if err != nil {
 		return "", 0, "bad width in $GENERATE"
 	}
 

go.mod

@@ -3,9 +3,9 @@ module github.com/miekg/dns
 go 1.19
 
 require (
-	golang.org/x/net v0.15.0
-	golang.org/x/sync v0.3.0
-	golang.org/x/sys v0.12.0
+	golang.org/x/net v0.17.0
+	golang.org/x/sync v0.4.0
+	golang.org/x/sys v0.13.0
 	golang.org/x/tools v0.13.0
 )
 

go.sum

@@ -1,10 +1,10 @@
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/net v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
-golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
-golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
-golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
-golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
+golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/tools v0.13.0 h1:Iey4qkscZuv0VvIt8E0neZjtPVQFSc870HQ448QgEmQ=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=

listen_no_reuseport.go

@@ -7,16 +7,18 @@ import "net"
 
 const supportsReusePort = false
 
-func listenTCP(network, addr string, reuseport bool) (net.Listener, error) {
-	if reuseport {
+func listenTCP(network, addr string, reuseport, reuseaddr bool) (net.Listener, error) {
+	if reuseport || reuseaddr {
 		// TODO(tmthrgd): return an error?
 	}
 
 	return net.Listen(network, addr)
 }
 
-func listenUDP(network, addr string, reuseport bool) (net.PacketConn, error) {
-	if reuseport {
+const supportsReuseAddr = false
+
+func listenUDP(network, addr string, reuseport, reuseaddr bool) (net.PacketConn, error) {
+	if reuseport || reuseaddr {
 		// TODO(tmthrgd): return an error?
 	}
 

listen_reuseport.go

@@ -25,19 +25,41 @@ func reuseportControl(network, address string, c syscall.RawConn) error {
 	return opErr
 }
 
-func listenTCP(network, addr string, reuseport bool) (net.Listener, error) {
+const supportsReuseAddr = true
+
+func reuseaddrControl(network, address string, c syscall.RawConn) error {
+	var opErr error
+	err := c.Control(func(fd uintptr) {
+		opErr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_REUSEADDR, 1)
+	})
+	if err != nil {
+		return err
+	}
+
+	return opErr
+}
+
+func listenTCP(network, addr string, reuseport, reuseaddr bool) (net.Listener, error) {
 	var lc net.ListenConfig
-	if reuseport {
+	switch {
+	case reuseaddr && reuseport:
+	case reuseport:
 		lc.Control = reuseportControl
+	case reuseaddr:
+		lc.Control = reuseaddrControl
 	}
 
 	return lc.Listen(context.Background(), network, addr)
 }
 
-func listenUDP(network, addr string, reuseport bool) (net.PacketConn, error) {
+func listenUDP(network, addr string, reuseport, reuseaddr bool) (net.PacketConn, error) {
 	var lc net.ListenConfig
-	if reuseport {
+	switch {
+	case reuseaddr && reuseport:
+	case reuseport:
 		lc.Control = reuseportControl
+	case reuseaddr:
+		lc.Control = reuseaddrControl
 	}
 
 	return lc.ListenPacket(context.Background(), network, addr)

msg.go

@@ -501,30 +501,28 @@ func packTxtString(s string, msg []byte, offset int) (int, error) {
 	return offset, nil
 }
 
-func packOctetString(s string, msg []byte, offset int, tmp []byte) (int, error) {
-	if offset >= len(msg) || len(s) > len(tmp) {
+func packOctetString(s string, msg []byte, offset int) (int, error) {
+	if offset >= len(msg) || len(s) > 256*4+1 {
 		return offset, ErrBuf
 	}
-	bs := tmp[:len(s)]
-	copy(bs, s)
-	for i := 0; i < len(bs); i++ {
+	for i := 0; i < len(s); i++ {
 		if len(msg) <= offset {
 			return offset, ErrBuf
 		}
-		if bs[i] == '\\' {
+		if s[i] == '\\' {
 			i++
-			if i == len(bs) {
+			if i == len(s) {
 				break
 			}
 			// check for \DDD
-			if isDDD(bs[i:]) {
-				msg[offset] = dddToByte(bs[i:])
+			if isDDD(s[i:]) {
+				msg[offset] = dddToByte(s[i:])
 				i += 2
 			} else {
-				msg[offset] = bs[i]
+				msg[offset] = s[i]
 			}
 		} else {
-			msg[offset] = bs[i]
+			msg[offset] = s[i]
 		}
 		offset++
 	}