diff --git a/config.h b/config.h
index 18760c3..fa47152 100644
--- a/config.h
+++ b/config.h
@@ -39,7 +39,8 @@
 
 extern struct clat_config Global_Clatd_Config;
 
-int read_config(const char *file, const char *uplink_interface, const char *plat_prefix);
+int read_config(const char *file, const char *uplink_interface, const char *plat_prefix,
+        unsigned net_id);
 void config_generate_local_ipv6_subnet(struct in6_addr *interface_ip);
 
 #endif /* __CONFIG_H__ */