-add_executable(odhcpd src/odhcpd.c src/config.c src/router.c src/dhcpv6.c src/ndp.c src/md5.c src/dhcpv6-ia.c src/dhcpv4.c src/ubus.c)
-target_link_libraries(odhcpd resolv ubus ubox uci)
+if (${EXT_CER_ID})
+ add_definitions(-DEXT_CER_ID=${EXT_CER_ID})
+endif(${EXT_CER_ID})
+
+if(${UBUS})
+ add_definitions(-DWITH_UBUS)
+ set(EXT_SRC ${EXT_SRC} src/ubus.c)
+ set(EXT_LINK ${EXT_LINK} ubus)
+endif(${UBUS})
+
+add_executable(odhcpd src/odhcpd.c src/config.c src/router.c src/dhcpv6.c src/ndp.c src/dhcpv6-ia.c src/dhcpv4.c ${EXT_SRC})
+target_link_libraries(odhcpd resolv ubox uci ${EXT_LINK})