ngm_macfilter_hooks
const struct ngm_macfilter_hooks *const ngm_hooks =
(const struct ngm_macfilter_hooks *)(buf - OFFSETOF(struct ngm_macfilter_hooks, hooks));
struct ngm_macfilter_hooks *ngm_hooks;
resplen = sizeof(struct ngm_macfilter_hooks) + n * sizeof(struct ngm_macfilter_hook);
ngm_hooks = (struct ngm_macfilter_hooks *)resp->data;