A Len() to RR interface

This isn't yet finished, but it helps in asserting the amount of
space to alloc when packing a message

dns.go

@@ -91,6 +91,7 @@ func (e *Error) Error() string {
 type RR interface {
 	Header() *RR_Header
 	String() string
+	Len() int
 }
 
 // An RRset is a slice of RRs.
@@ -212,15 +213,21 @@ func (h *RR_Header) String() string {
 	return s
 }
 
+func (h *RR_Header) Len() int {
+        l, _ := IsDomainName(h.Name)
+        l += 10 // rrtype(2) + class(2) + ttl(4) + rdlength(2)
+        return int(l)
+}
+
 func zoneMatch(pattern, zone string) (ok bool) {
 	if len(pattern) == 0 {
 		return
 	}
-        if len(zone) == 0 {
+	if len(zone) == 0 {
-                zone = "."
+		zone = "."
-        }
+	}
-        pattern = Fqdn(pattern)
+	pattern = Fqdn(pattern)
-        zone = Fqdn(zone)
+	zone = Fqdn(zone)
 	i := 0
 	for {
 		ok = pattern[len(pattern)-1-i] == zone[len(zone)-1-i]

edns.go

@@ -75,6 +75,10 @@ func (rr *RR_OPT) String() string {
 	return s
 }
 
+func (rr *RR_OPT) Len() int {
+        return rr.Hdr.Len() + len(rr.Option)     // TODO: to small/large?
+}
+
 // TODO(mg)
 // Get the EDNS version (always 0 currently).
 func (rr *RR_OPT) Version() uint8 {

msg.go

@@ -1094,6 +1094,33 @@ func (dns *Msg) String() string {
 	return s
 }
 
+// Len return the message length (in uncompressed wirefmt).
+func (dns *Msg) Len() int {
+	// Message header is always 12 bytes       
+	l := 12
+	if len(dns.Question) > 0 {
+		for i := 0; i < len(dns.Question); i++ {
+			l += dns.Question[i].Len()
+		}
+	}
+	if len(dns.Answer) > 0 {
+		for i := 0; i < len(dns.Answer); i++ {
+			l += dns.Answer[i].Len()
+		}
+	}
+	if len(dns.Ns) > 0 {
+		for i := 0; i < len(dns.Ns); i++ {
+			l += dns.Ns[i].Len()
+		}
+	}
+	if len(dns.Extra) > 0 {
+		for i := 0; i < len(dns.Extra); i++ {
+			l += dns.Extra[i].Len()
+		}
+	}
+	return l
+}
+
 // Id return a 16 bits random number to be used as a
 // message id. The random provided should be good enough.
 func Id() uint16 {

types.go

@@ -136,11 +136,11 @@ type Question struct {
 
 func (q *Question) String() (s string) {
 	// prefix with ; (as in dig)
-        if len(q.Name) == 0 {
+	if len(q.Name) == 0 {
-	        s = ";.\t" // root label
+		s = ";.\t" // root label
-        } else {
+	} else {
-	        s = ";" + q.Name + "\t"
+		s = ";" + q.Name + "\t"
-        }
+	}
 	s = s + Class_str[q.Qclass] + "\t"
 	if _, ok := Rr_str[q.Qtype]; ok {
 		s += " " + Rr_str[q.Qtype]
@@ -150,6 +150,11 @@ func (q *Question) String() (s string) {
 	return s
 }
 
+func (q *Question) Len() int {
+	l, _ := IsDomainName(q.Name)
+	return int(l) + 4
+}
+
 type RR_ANY struct {
 	Hdr RR_Header
 	// Does not have any rdata
@@ -163,6 +168,10 @@ func (rr *RR_ANY) String() string {
 	return rr.Hdr.String()
 }
 
+func (rr *RR_ANY) Len() int {
+	return rr.Hdr.Len()
+}
+
 type RR_CNAME struct {
 	Hdr   RR_Header
 	Cname string "domain-name"
@@ -176,6 +185,11 @@ func (rr *RR_CNAME) String() string {
 	return rr.Hdr.String() + rr.Cname
 }
 
+func (rr *RR_CNAME) Len() int {
+	l, _ := IsDomainName(rr.Cname)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_HINFO struct {
 	Hdr RR_Header
 	Cpu string
@@ -190,6 +204,10 @@ func (rr *RR_HINFO) String() string {
 	return rr.Hdr.String() + rr.Cpu + " " + rr.Os
 }
 
+func (rr *RR_HINFO) Len() int {
+	return rr.Hdr.Len() + len(rr.Cpu) + len(rr.Os)
+}
+
 type RR_MB struct {
 	Hdr RR_Header
 	Mb  string "domain-name"
@@ -203,6 +221,11 @@ func (rr *RR_MB) String() string {
 	return rr.Hdr.String() + rr.Mb
 }
 
+func (rr *RR_MB) Len() int {
+	l, _ := IsDomainName(rr.Mb)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_MG struct {
 	Hdr RR_Header
 	Mg  string "domain-name"
@@ -216,6 +239,11 @@ func (rr *RR_MG) String() string {
 	return rr.Hdr.String() + rr.Mg
 }
 
+func (rr *RR_MG) Len() int {
+	l, _ := IsDomainName(rr.Mg)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_MINFO struct {
 	Hdr   RR_Header
 	Rmail string "domain-name"
@@ -230,6 +258,12 @@ func (rr *RR_MINFO) String() string {
 	return rr.Hdr.String() + rr.Rmail + " " + rr.Email
 }
 
+func (rr *RR_MINFO) Len() int {
+	l, _ := IsDomainName(rr.Rmail)
+	n, _ := IsDomainName(rr.Email)
+	return rr.Hdr.Len() + int(l) + int(n)
+}
+
 type RR_MR struct {
 	Hdr RR_Header
 	Mr  string "domain-name"
@@ -243,6 +277,11 @@ func (rr *RR_MR) String() string {
 	return rr.Hdr.String() + rr.Mr
 }
 
+func (rr *RR_MR) Len() int {
+	l, _ := IsDomainName(rr.Mr)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_MX struct {
 	Hdr  RR_Header
 	Pref uint16
@@ -257,6 +296,11 @@ func (rr *RR_MX) String() string {
 	return rr.Hdr.String() + strconv.Itoa(int(rr.Pref)) + " " + rr.Mx
 }
 
+func (rr *RR_MX) Len() int {
+	l, _ := IsDomainName(rr.Mx)
+	return rr.Hdr.Len() + int(l) + 2
+}
+
 type RR_NS struct {
 	Hdr RR_Header
 	Ns  string "domain-name"
@@ -270,6 +314,11 @@ func (rr *RR_NS) String() string {
 	return rr.Hdr.String() + rr.Ns
 }
 
+func (rr *RR_NS) Len() int {
+	l, _ := IsDomainName(rr.Ns)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_PTR struct {
 	Hdr RR_Header
 	Ptr string "domain-name"
@@ -283,6 +332,11 @@ func (rr *RR_PTR) String() string {
 	return rr.Hdr.String() + rr.Ptr
 }
 
+func (rr *RR_PTR) Len() int {
+	l, _ := IsDomainName(rr.Ptr)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_SOA struct {
 	Hdr     RR_Header
 	Ns      string "domain-name"
@@ -307,6 +361,12 @@ func (rr *RR_SOA) String() string {
 		" " + strconv.Itoa(int(rr.Minttl))
 }
 
+func (rr *RR_SOA) Len() int {
+	l, _ := IsDomainName(rr.Ns)
+	n, _ := IsDomainName(rr.Mbox)
+	return rr.Hdr.Len() + int(l) + int(n) + 20
+}
+
 type RR_TXT struct {
 	Hdr RR_Header
 	Txt string "txt"
@@ -320,6 +380,10 @@ func (rr *RR_TXT) String() string {
 	return rr.Hdr.String() + "\"" + rr.Txt + "\""
 }
 
+func (rr *RR_TXT) Len() int {
+	return rr.Hdr.Len() + len(rr.Txt) // TODO: always works?
+}
+
 type RR_SRV struct {
 	Hdr      RR_Header
 	Priority uint16
@@ -339,6 +403,11 @@ func (rr *RR_SRV) String() string {
 		strconv.Itoa(int(rr.Port)) + " " + rr.Target
 }
 
+func (rr *RR_SRV) Len() int {
+	l, _ := IsDomainName(rr.Target)
+	return rr.Hdr.Len() + int(l) + 6
+}
+
 type RR_NAPTR struct {
 	Hdr         RR_Header
 	Order       uint16
@@ -363,6 +432,10 @@ func (rr *RR_NAPTR) String() string {
 		rr.Replacement
 }
 
+func (rr *RR_NAPTR) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 // See RFC 4398.
 type RR_CERT struct {
 	Hdr         RR_Header
@@ -383,6 +456,10 @@ func (rr *RR_CERT) String() string {
 		" " + rr.Certificate
 }
 
+func (rr *RR_CERT) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 // See RFC 2672.
 type RR_DNAME struct {
 	Hdr    RR_Header
@@ -397,6 +474,11 @@ func (rr *RR_DNAME) String() string {
 	return rr.Hdr.String() + rr.Target
 }
 
+func (rr *RR_DNAME) Len() int {
+	l, _ := IsDomainName(rr.Target)
+	return rr.Hdr.Len() + int(l)
+}
+
 type RR_A struct {
 	Hdr RR_Header
 	A   net.IP "A"
@@ -410,6 +492,10 @@ func (rr *RR_A) String() string {
 	return rr.Hdr.String() + rr.A.String()
 }
 
+func (rr *RR_A) Len() int {
+	return rr.Hdr.Len() + 4 /// 4 bytes?
+}
+
 type RR_AAAA struct {
 	Hdr  RR_Header
 	AAAA net.IP "AAAA"
@@ -423,6 +509,10 @@ func (rr *RR_AAAA) String() string {
 	return rr.Hdr.String() + rr.AAAA.String()
 }
 
+func (rr *RR_AAAA) Len() int {
+	return rr.Hdr.Len() + 16
+}
+
 type RR_LOC struct {
 	Hdr       RR_Header
 	Version   uint8
@@ -443,6 +533,10 @@ func (rr *RR_LOC) String() string {
 	return rr.Hdr.String() + "TODO"
 }
 
+func (rr *RR_LOC) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 type RR_RRSIG struct {
 	Hdr         RR_Header
 	TypeCovered uint16
@@ -472,6 +566,12 @@ func (rr *RR_RRSIG) String() string {
 		" " + rr.Signature
 }
 
+func (rr *RR_RRSIG) Len() int {
+	l, _ := IsDomainName(rr.SignerName)
+	return rr.Hdr.Len() + int(l) + len(rr.Signature) + 18
+	// base64 string, wordt iets minder dus
+}
+
 type RR_NSEC struct {
 	Hdr        RR_Header
 	NextDomain string   "domain-name"
@@ -494,6 +594,12 @@ func (rr *RR_NSEC) String() string {
 	return s
 }
 
+func (rr *RR_NSEC) Len() int {
+	l, _ := IsDomainName(rr.NextDomain)
+	return rr.Hdr.Len() + int(l) + len(rr.TypeBitMap)
+	// This is also shorter due to the windowing
+}
+
 type RR_DS struct {
 	Hdr        RR_Header
 	KeyTag     uint16
@@ -513,6 +619,10 @@ func (rr *RR_DS) String() string {
 		" " + strings.ToUpper(rr.Digest)
 }
 
+func (rr *RR_DS) Len() int {
+	return rr.Hdr.Len() + 4 + len(rr.Digest)/2
+}
+
 type RR_DLV struct {
 	Hdr        RR_Header
 	KeyTag     uint16
@@ -532,6 +642,10 @@ func (rr *RR_DLV) String() string {
 		" " + strings.ToUpper(rr.Digest)
 }
 
+func (rr *RR_DLV) Len() int {
+	return rr.Hdr.Len() + 4 + len(rr.Digest)/2
+}
+
 type RR_KX struct {
 	Hdr        RR_Header
 	Preference uint16
@@ -547,6 +661,10 @@ func (rr *RR_KX) String() string {
 		" " + rr.Exchanger
 }
 
+func (rr *RR_KX) Len() int {
+	return 0
+}
+
 type RR_TA struct {
 	Hdr        RR_Header
 	KeyTag     uint16
@@ -566,6 +684,10 @@ func (rr *RR_TA) String() string {
 		" " + strings.ToUpper(rr.Digest)
 }
 
+func (rr *RR_TA) Len() int {
+	return rr.Hdr.Len() + 4 + len(rr.Digest)/2
+}
+
 type RR_TALINK struct {
 	Hdr          RR_Header
 	PreviousName string "domain"
@@ -581,6 +703,12 @@ func (rr *RR_TALINK) String() string {
 		" " + rr.PreviousName + " " + rr.NextName
 }
 
+func (rr *RR_TALINK) Len() int {
+	l, _ := IsDomainName(rr.PreviousName)
+	n, _ := IsDomainName(rr.NextName)
+	return rr.Hdr.Len() + int(l) + int(n)
+}
+
 type RR_SSHFP struct {
 	Hdr         RR_Header
 	Algorithm   uint8
@@ -598,6 +726,10 @@ func (rr *RR_SSHFP) String() string {
 		" " + strings.ToUpper(rr.FingerPrint)
 }
 
+func (rr *RR_SSHFP) Len() int {
+        return rr.Hdr.Len() + 2 + len(rr.FingerPrint)/2
+}
+
 type RR_DNSKEY struct {
 	Hdr       RR_Header
 	Flags     uint16
@@ -617,6 +749,10 @@ func (rr *RR_DNSKEY) String() string {
 		" " + rr.PublicKey
 }
 
+func (rr *RR_DNSKEY) Len() int {
+        return rr.Hdr.Len() + 4 + len(rr.PublicKey)     // todo: base64
+}
+
 type RR_NSEC3 struct {
 	Hdr        RR_Header
 	Hash       uint8
@@ -650,6 +786,11 @@ func (rr *RR_NSEC3) String() string {
 	return s
 }
 
+func (rr *RR_NSEC3) Len() int {
+        return rr.Hdr.Len() + 6 + len(rr.Salt)/2+1 + len(rr.NextDomain)+1 + len(rr.TypeBitMap)
+        // TODO: size-base32 and typebitmap
+}
+
 type RR_NSEC3PARAM struct {
 	Hdr        RR_Header
 	Hash       uint8
@@ -672,13 +813,8 @@ func (rr *RR_NSEC3PARAM) String() string {
 	return s
 }
 
-// saltString converts a NSECX salt to uppercase and
+func (rr *RR_NSEC3PARAM) Len() int {
-// returns "-" when it is empty
+	return rr.Hdr.Len() + 0
-func saltString(s string) string {
-	if len(s) == 0 {
-		return "-"
-	}
-	return strings.ToUpper(s)
 }
 
 // See RFC 4408.
@@ -695,6 +831,10 @@ func (rr *RR_SPF) String() string {
 	return rr.Hdr.String() + "\"" + rr.Txt + "\""
 }
 
+func (rr *RR_SPF) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 type RR_TKEY struct {
 	Hdr        RR_Header
 	Algorithm  string "domain-name"
@@ -717,6 +857,10 @@ func (rr *RR_TKEY) String() string {
 	return ""
 }
 
+func (rr *RR_TKEY) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 // Unknown RR representation
 type RR_RFC3597 struct {
 	Hdr   RR_Header
@@ -733,6 +877,10 @@ func (rr *RR_RFC3597) String() string {
 	return s
 }
 
+func (rr *RR_RFC3597) Len() int {
+	return rr.Hdr.Len() + len(rr.Rdata)/2
+}
+
 type RR_URI struct {
 	Hdr      RR_Header
 	Priority uint16
@@ -750,6 +898,10 @@ func (rr *RR_URI) String() string {
 		" " + rr.Target
 }
 
+func (rr *RR_URI) Len() int {
+	return rr.Hdr.Len() + 0
+}
+
 type RR_DHCID struct {
 	Hdr    RR_Header
 	Digest string "base64"
@@ -763,6 +915,10 @@ func (rr *RR_DHCID) String() string {
 	return rr.Hdr.String() + rr.Digest
 }
 
+func (rr *RR_DHCID) Len() int {
+        return rr.Hdr.Len() + 0
+}
+
 // RFC 2845.
 type RR_TSIG struct {
 	Hdr        RR_Header
@@ -795,11 +951,15 @@ func (rr *RR_TSIG) String() string {
 		" " + rr.OtherData
 }
 
+func (rr *RR_TSIG) Len() int {
+        return rr.Hdr.Len() + 0
+}
+
 // Translate the RRSIG's incep. and expir. time to the correct date.
 // Taking into account serial arithmetic (RFC 1982) [TODO]
 func timeToDate(t uint32) string {
-//	utc := time.Now().UTC().Unix()
+	//	utc := time.Now().UTC().Unix()
-//	mod := (int64(t) - utc) / Year68
+	//	mod := (int64(t) - utc) / Year68
 	ti := time.Unix(int64(t), 0).UTC()
 	return ti.Format("20060102150405")
 }
@@ -813,7 +973,7 @@ func dateToTime(s string) (uint32, error) {
 		return 0, e
 	}
 	mod := t.Unix() / Year68
-        ti := uint32(t.Unix() - (mod * Year68))
+	ti := uint32(t.Unix() - (mod * Year68))
 	return ti, nil
 }
 
@@ -828,6 +988,15 @@ func tsigTimeToDate(t uint64) string {
 	*/
 }
 
+// saltString converts a NSECX salt to uppercase and
+// returns "-" when it is empty
+func saltString(s string) string {
+	if len(s) == 0 {
+		return "-"
+	}
+	return strings.ToUpper(s)
+}
+
 // Map of constructors for each RR wire type.
 var rr_mk = map[uint16]func() RR{
 	TypeCNAME:      func() RR { return new(RR_CNAME) },