add support for get/set x509 version

closes #61

cert.go

@@ -43,6 +43,16 @@ const (
 	EVP_SHA512    EVP_MD = iota
 )
 
+// X509_Version represents a version on an x509 certificate.
+type X509_Version int
+
+// Specify constants for x509 versions because the standard states that they
+// are represented internally as one lower than the common version name.
+const (
+	X509_V1 X509_Version = 0
+	X509_V3 X509_Version = 2
+)
+
 type Certificate struct {
 	x      *C.X509
 	Issuer *Certificate
@@ -388,3 +398,17 @@ func (c *Certificate) GetSerialNumberHex() (serial string) {
 	C.X_OPENSSL_free(unsafe.Pointer(hex))
 	return
 }
+
+// GetVersion returns the X509 version of the certificate.
+func (c *Certificate) GetVersion() X509_Version {
+	return X509_Version(C.X_X509_get_version(c.x))
+}
+
+// SetVersion sets the X509 version of the certificate.
+func (c *Certificate) SetVersion(version X509_Version) error {
+	cvers := C.long(version)
+	if C.X_X509_set_version(c.x, cvers) != 1 {
+		return errors.New("failed to set certificate version")
+	}
+	return nil
+}

cert_test.go

@@ -21,7 +21,7 @@ import (
 )
 
 func TestCertGenerate(t *testing.T) {
-	key, err := GenerateRSAKey(2048)
+	key, err := GenerateRSAKey(768)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -43,7 +43,7 @@ func TestCertGenerate(t *testing.T) {
 }
 
 func TestCAGenerate(t *testing.T) {
-	cakey, err := GenerateRSAKey(2048)
+	cakey, err := GenerateRSAKey(768)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -70,7 +70,7 @@ func TestCAGenerate(t *testing.T) {
 	if err := ca.Sign(cakey, EVP_SHA256); err != nil {
 		t.Fatal(err)
 	}
-	key, err := GenerateRSAKey(2048)
+	key, err := GenerateRSAKey(768)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -102,7 +102,7 @@ func TestCAGenerate(t *testing.T) {
 }
 
 func TestCertGetNameEntry(t *testing.T) {
-	key, err := GenerateRSAKey(2048)
+	key, err := GenerateRSAKey(768)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -137,3 +137,28 @@ func TestCertGetNameEntry(t *testing.T) {
 		t.Fatalf("entry should be empty; got %q", entry)
 	}
 }
+
+func TestCertVersion(t *testing.T) {
+	key, err := GenerateRSAKey(768)
+	if err != nil {
+		t.Fatal(err)
+	}
+	info := &CertificateInfo{
+		Serial:       big.NewInt(int64(1)),
+		Issued:       0,
+		Expires:      24 * time.Hour,
+		Country:      "US",
+		Organization: "Test",
+		CommonName:   "localhost",
+	}
+	cert, err := NewCertificate(info, key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := cert.SetVersion(X509_V3); err != nil {
+		t.Fatal(err)
+	}
+	if vers := cert.GetVersion(); vers != X509_V3 {
+		t.Fatalf("bad version: %d", vers)
+	}
+}

shim.c

@@ -701,3 +701,11 @@ int X_sk_X509_num(STACK_OF(X509) *sk) {
 X509 *X_sk_X509_value(STACK_OF(X509)* sk, int i) {
    return sk_X509_value(sk, i);
 }
+
+long X_X509_get_version(const X509 *x) {
+	return X509_get_version(x);
+}
+
+int X_X509_set_version(X509 *x, long version) {
+	return X509_set_version(x, version);
+}

shim.h

@@ -158,6 +158,8 @@ extern const ASN1_TIME *X_X509_get0_notBefore(const X509 *x);
 extern const ASN1_TIME *X_X509_get0_notAfter(const X509 *x);
 extern int X_sk_X509_num(STACK_OF(X509) *sk);
 extern X509 *X_sk_X509_value(STACK_OF(X509)* sk, int i);
+extern long X_X509_get_version(const X509 *x);
+extern int X_X509_set_version(X509 *x, long version);
 
 /* PEM methods */
 extern int X_PEM_write_bio_PrivateKey_traditional(BIO *bio, EVP_PKEY *key, const EVP_CIPHER *enc, unsigned char *kstr, int klen, pem_password_cb *cb, void *u);

sni_test.go

@@ -1,23 +0,0 @@
-// Copyright (C) 2017. See AUTHORS.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//   http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package openssl
-
-import "fmt"
-
-// We can implemant SNI rfc6066 (http://tools.ietf.org/html/rfc6066) on the server side using foolowing callback.
-// You should implement context storage (tlsCtxStorage) by your self.
-func ExampleSetTLSExtServernameCallback() {
-	fmt.Println("Hello")
-}