Factor repeated preprocessor condition to a macro

The condition is a complex and repeated a few times. There were already some
inconsistencies in the repetitions as some of them forgot about DES.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index b371094..06188be 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -152,6 +152,15 @@
 #define MBEDTLS_SSL_RETRANS_WAITING         2
 #define MBEDTLS_SSL_RETRANS_FINISHED        3
 
+/* For CBC-specific encrypt/decrypt code */
+#if defined(MBEDTLS_CIPHER_MODE_CBC) &&                               \
+    ( defined(MBEDTLS_AES_C)      ||                                  \
+      defined(MBEDTLS_CAMELLIA_C) ||                                  \
+      defined(MBEDTLS_ARIA_C)     ||                                  \
+      defined(MBEDTLS_DES_C) )
+#define MBEDTLS_SSL_SOME_SUITES_USE_CBC
+#endif
+
 /*
  * Allow extra bytes for record, authentication and encryption overhead:
  * counter (8) + header (5) + IV(16) + MAC (16-48) + padding (0-256)
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index a40b46a..34485d2 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1433,8 +1433,7 @@
 #endif /* MBEDTLS_SSL_PROTO_SSL3 */
 
 #if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER) ||     \
-    ( defined(MBEDTLS_CIPHER_MODE_CBC) &&                                  \
-      ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_CAMELLIA_C) || defined(MBEDTLS_ARIA_C)) )
+    defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC)
 #define SSL_SOME_MODES_USE_MAC
 #endif
 
@@ -1669,8 +1668,7 @@
     }
     else
 #endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C */
-#if defined(MBEDTLS_CIPHER_MODE_CBC) &&                                    \
-    ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_CAMELLIA_C) || defined(MBEDTLS_ARIA_C) )
+#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC)
     if( mode == MBEDTLS_MODE_CBC )
     {
         int ret;
@@ -1789,8 +1787,7 @@
 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
     }
     else
-#endif /* MBEDTLS_CIPHER_MODE_CBC &&
-          ( MBEDTLS_AES_C || MBEDTLS_CAMELLIA_C || MBEDTLS_ARIA_C ) */
+#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC */
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
@@ -1962,8 +1959,7 @@
     }
     else
 #endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C */
-#if defined(MBEDTLS_CIPHER_MODE_CBC) &&                                    \
-    ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_CAMELLIA_C) || defined(MBEDTLS_ARIA_C) )
+#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC)
     if( mode == MBEDTLS_MODE_CBC )
     {
         /*
@@ -2176,8 +2172,7 @@
         ssl->in_msglen -= padlen;
     }
     else
-#endif /* MBEDTLS_CIPHER_MODE_CBC &&
-          ( MBEDTLS_AES_C || MBEDTLS_CAMELLIA_C || MBEDTLS_ARIA_C ) */
+#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC) */
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );