Add SSL_CIPHER_is_DHE.

Change-Id: I158d1fa1a6b70a278054862326562988c97911b5
Reviewed-on: https://boringssl-review.googlesource.com/8140
Reviewed-by: David Benjamin <davidben@google.com>

include/openssl/ssl.h

@@ -1095,6 +1095,9 @@ OPENSSL_EXPORT int SSL_CIPHER_is_block_cipher(const SSL_CIPHER *cipher);
 /* SSL_CIPHER_is_ECDSA returns one if |cipher| uses ECDSA. */
 OPENSSL_EXPORT int SSL_CIPHER_is_ECDSA(const SSL_CIPHER *cipher);
 
+/* SSL_CIPHER_is_DHE returns one if |cipher| uses DHE. */
+OPENSSL_EXPORT int SSL_CIPHER_is_DHE(const SSL_CIPHER *cipher);
+
 /* SSL_CIPHER_is_ECDHE returns one if |cipher| uses ECDHE. */
 OPENSSL_EXPORT int SSL_CIPHER_is_ECDHE(const SSL_CIPHER *cipher);
 

ssl/ssl_cipher.c

@@ -1691,6 +1691,10 @@ int SSL_CIPHER_is_ECDSA(const SSL_CIPHER *cipher) {
   return (cipher->algorithm_auth & SSL_aECDSA) != 0;
 }
 
+int SSL_CIPHER_is_DHE(const SSL_CIPHER *cipher) {
+  return (cipher->algorithm_mkey & SSL_kDHE) != 0;
+}
+
 int SSL_CIPHER_is_ECDHE(const SSL_CIPHER *cipher) {
   return (cipher->algorithm_mkey & SSL_kECDHE) != 0;
 }