Helper functions for base64 encoding/decoding

dnssec.go

@@ -8,7 +8,6 @@ import (
 	"crypto/rsa"
         "crypto/rand"
 	"encoding/hex"
-	"encoding/base64"
 	"hash"
 	"time"
 	"io"
@@ -260,9 +259,7 @@ func (s *RR_RRSIG) Sign(k PrivateKey, rrset RRset) bool {
                         if err != nil {
                                 return false
                         }
-                        b64 := make([]byte, base64.StdEncoding.EncodedLen(len(signature)))
-                        base64.StdEncoding.Encode(b64, signature)
-                        s.Signature = string(b64)
+                        s.Signature = unpackBase64(signature)
                 default:
                         // Not given the correct key
                         return false
@@ -410,20 +407,19 @@ func (s *RR_RRSIG) PeriodOK() bool {
 
 // Return the signatures base64 encodedig sigdata as a byte slice.
 func (s *RR_RRSIG) sigBuf() []byte {
-	sigbuf := make([]byte, 1024) // TODO(mg) length!
-	sigbuflen := base64.StdEncoding.DecodedLen(len(s.Signature))
-	sigbuflen, _ = base64.StdEncoding.Decode(sigbuf[0:sigbuflen], []byte(s.Signature))
-	sigbuf = sigbuf[:sigbuflen]
+        sigbuf, err := packBase64([]byte(s.Signature))
+        if err != nil {
+                return nil
+        }
 	return sigbuf
 }
 
 // Extract the RSA public key from the Key record
 func (k *RR_DNSKEY) pubKeyRSA() *rsa.PublicKey {
-	// Buffer holding the key data
-	keybuf := make([]byte, 1024)
-	keybuflen := base64.StdEncoding.DecodedLen(len(k.PubKey))
-	keybuflen, _ = base64.StdEncoding.Decode(keybuf[0:keybuflen], []byte(k.PubKey))
-	keybuf = keybuf[:keybuflen]
+        keybuf, err := packBase64([]byte(k.PubKey))
+        if err != nil {
+                return nil
+        }
 
 	// RFC 2537/3110, section 2. RSA Public KEY Resource Records
 	// Length is in the 0th byte, unless its zero, then it

keygen.go

@@ -4,11 +4,10 @@ import (
 	"os"
 	"crypto/rsa"
 	"crypto/rand"
-	"encoding/base64"
 )
 
-// Empty interface so all crypty private key
-// can be grouped together
+// Empty interface that is used a wrapper around all possible
+// private key implementation from the crypto package.
 type PrivateKey interface{}
 
 // io.Reader
@@ -16,10 +15,10 @@ type PrivateKey interface{}
 // PrivateKeyFromString
 // PrivateKeyToDNSKEY
 
-// Generate a Key of the given bit size.
+// Generate a key of the given bit size.
 // The public part is directly put inside the DNSKEY record. 
 // The Algorithm in the key must be set as this will define
-// what kind of DNSKEY will be generated
+// what kind of DNSKEY will be generated.
 func (r *RR_DNSKEY) Generate(bits int) (PrivateKey, os.Error) {
 	switch r.Algorithm {
 	case AlgRSAMD5, AlgRSASHA1, AlgRSASHA256:
@@ -56,10 +55,7 @@ func (r *RR_DNSKEY) Generate(bits int) (PrivateKey, os.Error) {
 			return nil, &Error{Error: "Exponent too large"}
 		}
 		keybuf = append(keybuf, priv.PublicKey.N.Bytes()...)
-
-		b64 := make([]byte, base64.StdEncoding.EncodedLen(len(keybuf)))
-		base64.StdEncoding.Encode(b64, keybuf)
-		r.PubKey = string(b64)
+		r.PubKey = unpackBase64(keybuf)
 		return priv, nil
 	}
 	return nil, nil // Dummy return

msg.go

@@ -286,10 +286,10 @@ func packStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int, o
 					msg[off] = byte(fv.Elem(j).(*reflect.UintValue).Get())
 					off++
 				}
-			case "NSEC":    // NSEC/NSEC3
+			case "NSEC": // NSEC/NSEC3
 				for j := 0; j < val.Field(i).(*reflect.SliceValue).Len(); j++ {
-				         var _ = byte(fv.Elem(j).(*reflect.UintValue).Get())
-                                }
+					var _ = byte(fv.Elem(j).(*reflect.UintValue).Get())
+				}
 				// handle type bit maps
 			}
 		case *reflect.StructValue:
@@ -342,7 +342,7 @@ func packStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int, o
 			default:
 				return len(msg), false
 			case "base64":
-                                // TODO(mg) use the Len as return from the conversion (not used right now)
+				// TODO(mg) use the Len as return from the conversion (not used right now)
 				b64len := base64.StdEncoding.DecodedLen(len(s))
 				_, err := base64.StdEncoding.Decode(msg[off:off+b64len], []byte(s))
 				if err != nil {
@@ -559,10 +559,7 @@ func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int,
 				default:
 					consumed = 0 // TODO
 				}
-                                // TODO(mg) check return value of encoding
-				b64 := make([]byte, base64.StdEncoding.EncodedLen(len(msg[off:off+rdlength-consumed])))
-				base64.StdEncoding.Encode(b64, msg[off:off+rdlength-consumed])
-				s = string(b64)
+				s = unpackBase64(msg[off : off+rdlength-consumed])
 				off += rdlength - consumed
 			case "domain-name":
 				s, off, ok = unpackDomainName(msg, off)
@@ -600,6 +597,24 @@ func unpackStruct(any interface{}, msg []byte, off int) (off1 int, ok bool) {
 	return off, ok
 }
 
+func unpackBase64(b []byte) string {
+	b64 := make([]byte, base64.StdEncoding.EncodedLen(len(b)))
+	base64.StdEncoding.Encode(b64, b)
+	return string(b64)
+}
+
+// Helper function for packing, mostly used in dnssec.go
+func packBase64(s []byte) ([]byte, os.Error) {
+	b64len := base64.StdEncoding.DecodedLen(len(s))
+	buf := make([]byte, b64len)
+	n, err := base64.StdEncoding.Decode(buf, []byte(s))
+	if err != nil {
+		return nil, err
+	}
+	buf = buf[:n]
+	return buf, nil
+}
+
 // Resource record packer.
 func packRR(rr RR, msg []byte, off int) (off2 int, ok bool) {
 	if rr == nil {
@@ -696,6 +711,7 @@ func (h *MsgHdr) String() string {
 	return s
 }
 
+// Pack a msg: convert it to wire format.
 func (dns *Msg) Pack() (msg []byte, ok bool) {
 	var dh Header
 
@@ -764,6 +780,7 @@ func (dns *Msg) Pack() (msg []byte, ok bool) {
 	return msg[:off], true
 }
 
+// Unpack a binary message to a Msg structure.
 func (dns *Msg) Unpack(msg []byte) bool {
 	// Header.
 	var dh Header
@@ -808,7 +825,7 @@ func (dns *Msg) Unpack(msg []byte) bool {
 	return true
 }
 
-// Convert a complete message to a string, use dig-like output.
+// Convert a complete message to a string using dig-like output.
 func (dns *Msg) String() string {
 	if dns == nil {
 		return "<nil> MsgHdr"