login-common: Avoid using client_destroy_success() when mail_max_user…

…ip_connections is reached

This was currently the only way how data != NULL here.

This change destroys ssl_proxy on client_destroy() instead of
client_unref(), but that doesn't make much of a practical difference. This
new behavior is a bit more correct though.

src/login-common/client-common-auth.c

@@ -729,8 +729,11 @@ sasl_callback(struct client *client, enum sasl_server_reply sasl_reply,
 
 		if (data == NULL)
 			client_destroy_internal_failure(client);
-		else
-			client_destroy_success(client, data);
+		else {
+			/* e.g. mail_max_userip_connections is reached */
+			client->no_extra_disconnect_reason = TRUE;
+			client_destroy(client, data);
+		}
 		break;
 	case SASL_SERVER_REPLY_CONTINUE:
 		i_assert(client->v.auth_send_challenge != NULL);

src/login-common/client-common.c

@@ -232,7 +232,8 @@ void client_destroy(struct client *client, const char *reason)
 
 	pool_unref(&client->preproxy_pool);
 
-	if (!client->login_success && reason != NULL) {
+	if (!client->login_success &&
+	    !client->no_extra_disconnect_reason && reason != NULL) {
 		const char *extra_reason =
 			client_get_extra_disconnect_reason(client);
 		if (extra_reason[0] != '\0')

src/login-common/client-common.h

@@ -199,6 +199,7 @@ struct client {
 	bool destroyed:1;
 	bool input_blocked:1;
 	bool login_success:1;
+	bool no_extra_disconnect_reason:1;
 	bool starttls:1;
 	bool tls:1;
 	bool secured:1;