created signature_scheme_from_oid() helper function

src/libstrongswan/credentials/keys/public_key.c

@@ -13,6 +13,8 @@
  * for more details.
  */
 
+#include <asn1/oid.h>
+
 #include "public_key.h"
 
 ENUM(key_type_names, KEY_RSA, KEY_DSA,
@@ -21,7 +23,8 @@ ENUM(key_type_names, KEY_RSA, KEY_DSA,
 	"DSA"
 );
 
-ENUM(signature_scheme_names, SIGN_DEFAULT, SIGN_ECDSA_521,
+ENUM(signature_scheme_names, SIGN_UNKNOWN, SIGN_ECDSA_521,
+	"UNKNOWN",
 	"DEFAULT",
 	"RSA_EMSA_PKCS1_NULL",
 	"RSA_EMSA_PKCS1_MD5",
@@ -35,3 +38,33 @@ ENUM(signature_scheme_names, SIGN_DEFAULT, SIGN_ECDSA_521,
 	"ECDSA-521",
 );
 
+/*
+ * Defined in header.
+ */
+signature_scheme_t signature_scheme_from_oid(int oid)
+{
+	switch (oid)
+	{
+		case OID_MD5_WITH_RSA:
+		case OID_MD5:
+			return SIGN_RSA_EMSA_PKCS1_MD5;
+		case OID_SHA1_WITH_RSA:
+		case OID_SHA1:
+			return SIGN_RSA_EMSA_PKCS1_SHA1;
+		case OID_SHA256_WITH_RSA:
+		case OID_SHA256:
+			return SIGN_RSA_EMSA_PKCS1_SHA256;
+		case OID_SHA384_WITH_RSA:
+		case OID_SHA384:
+			return SIGN_RSA_EMSA_PKCS1_SHA384;
+		case OID_SHA512_WITH_RSA:
+		case OID_SHA512:
+			return SIGN_RSA_EMSA_PKCS1_SHA512;
+		case OID_ECDSA_WITH_SHA1:
+		case OID_EC_PUBLICKEY:
+			return SIGN_ECDSA_WITH_SHA1;
+		default:
+			return SIGN_UNKNOWN;
+	}
+}
+

src/libstrongswan/credentials/keys/public_key.h

@@ -58,6 +58,8 @@ extern enum_name_t *key_type_names;
  * variants is OCTET_STRING instead of the default BIT_STRING.
  */
 enum signature_scheme_t {
+	/** Unknown signature scheme                                       */
+	SIGN_UNKNOWN,
 	/** Default scheme of the underlying crypto system                 */
 	SIGN_DEFAULT,
 	/** EMSA-PKCS1_v1.5 signature over digest without digestInfo       */
@@ -164,4 +166,12 @@ struct public_key_t {
 	void (*destroy)(public_key_t *this);
 };
 
+/**
+ * Conversion of ASN.1 signature or hash OID to signature scheme.
+ * 
+ * @param oid			ASN.1 OID
+ * @return				signature_scheme, SIGN_UNKNOWN if OID is unsupported
+ */
+signature_scheme_t signature_scheme_from_oid(int oid);
+
 #endif /** PUBLIC_KEY_H_ @}*/