[Feature] use_domain_sign_inbound

lualib/lua_dkim_tools.lua

@@ -98,6 +98,10 @@ local function prepare_dkim_signing(N, task, settings)
     dkim_domain = get_dkim_domain('use_domain_sign_local')
     rspamd_logger.debugm(N, task, 'local: use domain(%s) for signature: %s',
       settings.use_domain_sign_local, dkim_domain)
+  elseif settings.use_domain_sign_inbound and not is_local and not auser then
+    dkim_domain = get_dkim_domain('use_domain_sign_inbound')
+    rspamd_logger.debugm(N, task, 'inbound: use domain(%s) for signature: %s',
+      settings.use_domain_sign_inbound, dkim_domain)
   else
     dkim_domain = get_dkim_domain('use_domain')
     rspamd_logger.debugm(N, task, 'use domain(%s) for signature: %s',