certificate_t->issued_by takes an argument to receive signature scheme

src/libstrongswan/credentials/certificates/certificate.h

@@ -143,9 +143,11 @@ struct certificate_t {
 	 * Check if this certificate is issued and signed by a specific issuer.
 	 *
 	 * @param issuer	issuer's certificate
+	 * @param scheme	receives signature scheme used during verification
 	 * @return			TRUE if certificate issued by issuer and trusted
 	 */
-	bool (*issued_by)(certificate_t *this, certificate_t *issuer);
+	bool (*issued_by)(certificate_t *this, certificate_t *issuer,
+					  signature_scheme_t *scheme);
 
 	/**
 	 * Get the public key associated to this certificate.

src/libstrongswan/credentials/sets/cert_cache.c

@@ -165,7 +165,7 @@ METHOD(cert_cache_t, issued_by, bool,
 		}
 	}
 	/* no cache hit, check and cache signature */
-	if (subject->issued_by(subject, issuer))
+	if (subject->issued_by(subject, issuer, NULL))
 	{
 		cache(this, subject, issuer);
 		return TRUE;