diff --git a/msg.go b/msg.go
index f0aec9d4..ffc0733c 100644
--- a/msg.go
+++ b/msg.go
@@ -576,17 +576,16 @@ func packOctetString(s string, msg []byte, offset int, tmp []byte) (int, error)
 	return offset, nil
 }
 
-func unpackTxt(msg []byte, offset, rdend int) ([]string, int, error) {
-	var err error
-	var ss []string
+func unpackTxt(msg []byte, off0 int) (ss []string, off int, err error) {
+	off = off0
 	var s string
-	for offset < rdend && err == nil {
-		s, offset, err = unpackTxtString(msg, offset)
+	for off < len(msg) && err == nil {
+		s, off, err = unpackTxtString(msg, off)
 		if err == nil {
 			ss = append(ss, s)
 		}
 	}
-	return ss, offset, err
+	return
 }
 
 func unpackTxtString(msg []byte, offset int) (string, int, error) {
@@ -960,17 +959,11 @@ func packStructCompress(any interface{}, msg []byte, off int, compression map[st
 	return off, err
 }
 
-// TODO(miek): Fix use of rdlength here
-
 // Unpack a reflect.StructValue from msg.
 // Same restrictions as packStructValue.
 func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err error) {
-	var lenrd int
 	lenmsg := len(msg)
 	for i := 0; i < val.NumField(); i++ {
-		if lenrd != 0 && lenrd == off {
-			break
-		}
 		if off > lenmsg {
 			return lenmsg, &Error{"bad offset unpacking"}
 		}
@@ -982,7 +975,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 			// therefore it's expected that this interface would be PrivateRdata
 			switch data := fv.Interface().(type) {
 			case PrivateRdata:
-				n, err := data.Unpack(msg[off:lenrd])
+				n, err := data.Unpack(msg[off:])
 				if err != nil {
 					return lenmsg, err
 				}
@@ -998,7 +991,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				// HIP record slice of name (or none)
 				var servers []string
 				var s string
-				for off < lenrd {
+				for off < lenmsg {
 					s, off, err = UnpackDomainName(msg, off)
 					if err != nil {
 						return lenmsg, err
@@ -1007,17 +1000,17 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				}
 				fv.Set(reflect.ValueOf(servers))
 			case `dns:"txt"`:
-				if off == lenmsg || lenrd == off {
+				if off == lenmsg {
 					break
 				}
 				var txt []string
-				txt, off, err = unpackTxt(msg, off, lenrd)
+				txt, off, err = unpackTxt(msg, off)
 				if err != nil {
 					return lenmsg, err
 				}
 				fv.Set(reflect.ValueOf(txt))
 			case `dns:"opt"`: // edns0
-				if off == lenrd {
+				if off == lenmsg {
 					// This is an EDNS0 (OPT Record) with no rdata
 					// We can safely return here.
 					break
@@ -1030,7 +1023,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				}
 				code, off = unpackUint16(msg, off)
 				optlen, off1 := unpackUint16(msg, off)
-				if off1+int(optlen) > lenrd {
+				if off1+int(optlen) > lenmsg {
 					return lenmsg, &Error{err: "overflow unpacking opt"}
 				}
 				switch code {
@@ -1095,7 +1088,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 					edns = append(edns, e)
 					off = off1 + int(optlen)
 				}
-				if off < lenrd {
+				if off < lenmsg {
 					goto Option
 				}
 				fv.Set(reflect.ValueOf(edns))
@@ -1106,10 +1099,10 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 						continue
 					}
 				}
-				if off == lenrd {
+				if off == lenmsg {
 					break // dyn. update
 				}
-				if off+net.IPv4len > lenrd || off+net.IPv4len > lenmsg {
+				if off+net.IPv4len > lenmsg {
 					return lenmsg, &Error{err: "overflow unpacking a"}
 				}
 				fv.Set(reflect.ValueOf(net.IPv4(msg[off], msg[off+1], msg[off+2], msg[off+3])))
@@ -1121,10 +1114,10 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 						continue
 					}
 				}
-				if off == lenrd {
+				if off == lenmsg {
 					break
 				}
-				if off+net.IPv6len > lenrd || off+net.IPv6len > lenmsg {
+				if off+net.IPv6len > lenmsg {
 					return lenmsg, &Error{err: "overflow unpacking aaaa"}
 				}
 				fv.Set(reflect.ValueOf(net.IP{msg[off], msg[off+1], msg[off+2], msg[off+3], msg[off+4],
@@ -1135,7 +1128,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				// Rest of the record is the bitmap
 				var serv []uint16
 				j := 0
-				for off < lenrd {
+				for off < lenmsg {
 					if off+1 > lenmsg {
 						return lenmsg, &Error{err: "overflow unpacking wks"}
 					}
@@ -1170,21 +1163,17 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				}
 				fv.Set(reflect.ValueOf(serv))
 			case `dns:"nsec"`: // NSEC/NSEC3
-				if off == lenrd {
+				if off == lenmsg {
 					break
 				}
 				// Rest of the record is the type bitmap
-				if off+2 > lenrd || off+2 > lenmsg {
+				if off+2 > lenmsg {
 					return lenmsg, &Error{err: "overflow unpacking nsecx"}
 				}
 				var nsec []uint16
 				length := 0
 				window := 0
-				for off+2 < lenrd {
-					if off+2 > lenmsg {
-						return lenmsg, &Error{err: "overflow unpacking nsecx"}
-					}
-
+				for off+2 < lenmsg {
 					window = int(msg[off])
 					length = int(msg[off+1])
 					//println("off, windows, length, end", off, window, length, endrr)
@@ -1241,7 +1230,12 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				return lenmsg, err
 			}
 			if val.Type().Field(i).Name == "Hdr" {
-				lenrd = off + int(val.FieldByName("Hdr").FieldByName("Rdlength").Uint())
+				lenrd := off + int(val.FieldByName("Hdr").FieldByName("Rdlength").Uint())
+				if lenrd > lenmsg {
+					return lenmsg, &Error{err: "overflowing header size"}
+				}
+				msg = msg[:lenrd]
+				lenmsg = len(msg)
 			}
 		case reflect.Uint8:
 			if off == lenmsg {
@@ -1272,6 +1266,9 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 			fv.SetUint(uint64(uint32(msg[off])<<24 | uint32(msg[off+1])<<16 | uint32(msg[off+2])<<8 | uint32(msg[off+3])))
 			off += 4
 		case reflect.Uint64:
+			if off == lenmsg {
+				break
+			}
 			switch val.Type().Field(i).Tag {
 			default:
 				if off+8 > lenmsg {
@@ -1298,30 +1295,26 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 			default:
 				return lenmsg, &Error{"bad tag unpacking string: " + val.Type().Field(i).Tag.Get("dns")}
 			case `dns:"octet"`:
-				strend := lenrd
-				if strend > lenmsg {
-					return lenmsg, &Error{err: "overflow unpacking octet"}
-				}
-				s = string(msg[off:strend])
-				off = strend
+				s = string(msg[off:])
+				off = lenmsg
 			case `dns:"hex"`:
-				hexend := lenrd
+				hexend := lenmsg
 				if val.FieldByName("Hdr").FieldByName("Rrtype").Uint() == uint64(TypeHIP) {
 					hexend = off + int(val.FieldByName("HitLength").Uint())
 				}
-				if hexend > lenrd || hexend > lenmsg {
-					return lenmsg, &Error{err: "overflow unpacking hex"}
+				if hexend > lenmsg {
+					return lenmsg, &Error{err: "overflow unpacking HIP hex"}
 				}
 				s = hex.EncodeToString(msg[off:hexend])
 				off = hexend
 			case `dns:"base64"`:
 				// Rest of the RR is base64 encoded value
-				b64end := lenrd
+				b64end := lenmsg
 				if val.FieldByName("Hdr").FieldByName("Rrtype").Uint() == uint64(TypeHIP) {
 					b64end = off + int(val.FieldByName("PublicKeyLength").Uint())
 				}
-				if b64end > lenrd || b64end > lenmsg {
-					return lenmsg, &Error{err: "overflow unpacking base64"}
+				if b64end > lenmsg {
+					return lenmsg, &Error{err: "overflow unpacking HIP base64"}
 				}
 				s = toBase64(msg[off:b64end])
 				off = b64end