diff --git a/Makefile b/Makefile
index ea8aedc1..e1d63e2f 100644
--- a/Makefile
+++ b/Makefile
@@ -15,6 +15,7 @@ GOFILES=\
 	edns.go\
 	keygen.go\
 	kscan.go\
+	labels.go\
 	msg.go\
 	nsec3.go \
 	rawmsg.go \
diff --git a/defaults.go b/defaults.go
index 3e8e4069..84b12f87 100644
--- a/defaults.go
+++ b/defaults.go
@@ -268,24 +268,3 @@ func Fqdn(s string) string {
 	}
 	return s + "."
 }
-
-// SplitLabels splits a domainname string into its labels.
-// No syntax checks are performed.
-// TODO: labels functions...
-func SplitLabels(s string) (labels []string) {
-        last := byte('.')
-        k := 0
-        l := 0
-	for i := 0; i < len(s); i++ {
-                if s[i] == '.' {
-                        if last == '\\' {
-                                // do nothing
-                                break
-                        }
-                        labels[l] = s[k:i]
-                        k = i+1 // + dot
-                }
-                last = s[i]
-        }
-        return
-}
diff --git a/dns.go b/dns.go
index 4f3e3ed4..9f5c693c 100644
--- a/dns.go
+++ b/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 := len(h.Name) + 1
+        l += 10 // rrtype(2) + class(2) + ttl(4) + rdlength(2)
+        return l
+}
+
 func zoneMatch(pattern, zone string) (ok bool) {
 	if len(pattern) == 0 {
 		return
 	}
-        if len(zone) == 0 {
-                zone = "."
-        }
-        pattern = Fqdn(pattern)
-        zone = Fqdn(zone)
+	if len(zone) == 0 {
+		zone = "."
+	}
+	pattern = Fqdn(pattern)
+	zone = Fqdn(zone)
 	i := 0
 	for {
 		ok = pattern[len(pattern)-1-i] == zone[len(zone)-1-i]
diff --git a/edns.go b/edns.go
index f003167d..6f6cecf0 100644
--- a/edns.go
+++ b/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 {
diff --git a/label_test.go b/label_test.go
new file mode 100644
index 00000000..4749b556
--- /dev/null
+++ b/label_test.go
@@ -0,0 +1,30 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestCompareLabels(t *testing.T) {
+        s1 := "www.miek.nl."
+        s2 := "miek.nl."
+        s3 := "www.bla.nl."
+        s4 := "nl.www.bla."
+        s5 := "nl"
+
+        if CompareLabels(s1, s2) != 2 {
+                t.Logf("%s with %s should be %d", s1, s2, 2)
+                t.Fail()
+        }
+        if CompareLabels(s1, s3) != 1 {
+                t.Logf("%s with %s should be %d", s1, s3, 1)
+                t.Fail()
+        }
+        if CompareLabels(s3, s4) != 0 {
+                t.Logf("%s with %s should be %d", s3, s4, 0)
+                t.Fail()
+        }
+        if CompareLabels(s1, s5) != 1 {
+                t.Logf("%s with %s should be %d", s1, s5, 1)
+                t.Fail()
+        }
+}
diff --git a/labels.go b/labels.go
new file mode 100644
index 00000000..7979dad2
--- /dev/null
+++ b/labels.go
@@ -0,0 +1,50 @@
+package dns
+
+// Holds a bunch of helper functions for dealing with labels.
+
+// SplitLabels splits a domainname string into its labels.
+func SplitLabels(s string) []string {
+	last := byte('.')
+	k := 0
+        labels := make([]string, 0)
+        s = Fqdn(s)     // Make fully qualified
+	for i := 0; i < len(s); i++ {
+		if s[i] == '.' {
+			if last == '\\' {
+				// do nothing
+				break
+			}
+			labels = append(labels,s[k:i])
+			k = i + 1 // + dot
+		}
+		last = s[i]
+	}
+	return labels
+}
+
+// CompareLabels compares the strings s1 and s2 and
+// returns how many labels they have in common starting from the right.
+// The comparison stops at the first inequality
+//
+// www.miek.nl and miek.nl have two labels in common: miek and nl
+// www.miek.nl and www.bla.nl have one label in common: nl
+func CompareLabels(s1, s2 string) (n int) {
+	l1 := SplitLabels(s1)
+	l2 := SplitLabels(s2)
+
+	x1 := len(l1)-1
+	x2 := len(l2)-1
+	for {
+                if x1 < 0 || x2 < 0 {
+                        break
+                }
+                if l1[x1] == l2[x2] {
+                        n++
+                } else {
+                        break
+                }
+                x1--
+                x2--
+	}
+        return
+}
diff --git a/msg.go b/msg.go
index c476eba7..b2744923 100644
--- a/msg.go
+++ b/msg.go
@@ -463,6 +463,10 @@ func packStructValue(val reflect.Value, msg []byte, off int) (off1 int, ok bool)
 					//fmt.Fprintf(os.Stderr, "dns: overflow packing (size-)hex string")
 					return lenmsg, false
 				}
+                                if off+hex.DecodedLen(len(s)) > lenmsg {
+                                        // Overflow
+                                        return lenmsg, false
+                                }
 				copy(msg[off:off+hex.DecodedLen(len(s))], h)
 				off += hex.DecodedLen(len(s))
 			case "size":
@@ -979,11 +983,8 @@ func (dns *Msg) Pack() (msg []byte, ok bool) {
 	dh.Nscount = uint16(len(ns))
 	dh.Arcount = uint16(len(extra))
 
-        // TODO: fix this MG
-	// Could work harder to calculate message size,
-	// but this is far more than we need and not
-	// big enough to hurt the allocator.
-	msg = make([]byte, DefaultMsgSize) // TODO, calculate REAL size
+        // TODO: still too much, but better than 64K
+	msg = make([]byte, dns.Len()*6)
 
 	// Pack it in: header and then the pieces.
 	off := 0
@@ -1099,6 +1100,33 @@ 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 {
diff --git a/types.go b/types.go
index 35ac3203..6f573314 100644
--- a/types.go
+++ b/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 {
-	        s = ";.\t" // root label
-        } else {
-	        s = ";" + q.Name + "\t"
-        }
+	if len(q.Name) == 0 {
+		s = ";.\t" // root label
+	} else {
+		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 := len(q.Name)+1
+	return 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 := len(rr.Cname)+1
+	return rr.Hdr.Len() + 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 := len(rr.Mb)+1
+	return rr.Hdr.Len() + 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 := len(rr.Mg)+1
+	return rr.Hdr.Len() + 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 := len(rr.Rmail)+1
+	n := len(rr.Email)+1
+	return rr.Hdr.Len() + l + 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 := len(rr.Mr)+1
+	return rr.Hdr.Len() + 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 := len(rr.Mx)+1
+	return rr.Hdr.Len() + 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 := len(rr.Ns)+1
+	return rr.Hdr.Len() + 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 := len(rr.Ptr)+1
+	return rr.Hdr.Len() + 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 := len(rr.Ns)+1
+	n := len(rr.Mbox)+1
+	return rr.Hdr.Len() + l + 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 := len(rr.Target)+1
+	return rr.Hdr.Len() + 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 := len(rr.Target)+1
+	return rr.Hdr.Len() + 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 := len(rr.SignerName)+1
+	return rr.Hdr.Len() + 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 := len(rr.NextDomain)+1
+	return rr.Hdr.Len() + 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 +703,10 @@ func (rr *RR_TALINK) String() string {
 		" " + rr.PreviousName + " " + rr.NextName
 }
 
+func (rr *RR_TALINK) Len() int {
+	return rr.Hdr.Len() + len(rr.PreviousName) + len(rr.NextName) + 2
+}
+
 type RR_SSHFP struct {
 	Hdr         RR_Header
 	Algorithm   uint8
@@ -598,6 +724,10 @@ 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 +747,10 @@ 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 +784,11 @@ 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 +811,8 @@ func (rr *RR_NSEC3PARAM) String() string {
 	return s
 }
 
-// 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)
+func (rr *RR_NSEC3PARAM) Len() int {
+	return rr.Hdr.Len() + 0
 }
 
 // See RFC 4408.
@@ -695,6 +829,10 @@ 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 +855,10 @@ 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 +875,10 @@ 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 +896,10 @@ 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 +913,10 @@ 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 +949,15 @@ 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()
-//	mod := (int64(t) - utc) / Year68
+	//	utc := time.Now().UTC().Unix()
+	//	mod := (int64(t) - utc) / Year68
 	ti := time.Unix(int64(t), 0).UTC()
 	return ti.Format("20060102150405")
 }
@@ -813,7 +971,7 @@ 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 +986,15 @@ 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) },