Function ng_apply_item

freebsd/netgraph/ng_base.c:2360–2503

* We have an item that was possibly queued somewhere. * It should contain all the information needed * to run it on the appropriate node/hook. * If there is apply pointer and we own the last reference, call apply(). */

 * If there is apply pointer and we own the last reference, call apply().
 */
static int
ng_apply_item(node_p node, item_p item, int rw)
{
	hook_p  hook;
	ng_rcvdata_t *rcvdata;
	ng_rcvmsg_t *rcvmsg;
	struct ng_apply_info *apply;
	int	error = 0, depth;

	/* Node and item are never optional. */
	KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
	KASSERT(item != NULL, ("ng_apply_item: item is NULL"));

	NGI_GET_HOOK(item, hook); /* clears stored hook */
#ifdef	NETGRAPH_DEBUG
	_ngi_check(item, __FILE__, __LINE__);
#endif

	apply = item->apply;
	depth = item->depth;

	switch (item->el_flags & NGQF_TYPE) {
	case NGQF_DATA:
		/*
		 * Check things are still ok as when we were queued.
		 */
		KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
		if (NG_HOOK_NOT_VALID(hook) ||
		    NG_NODE_NOT_VALID(node)) {
			error = EIO;
			NG_FREE_ITEM(item);
			break;
		}
		/*
		 * If no receive method, just silently drop it.
		 * Give preference to the hook over-ride method.
		 */
		if ((!(rcvdata = hook->hk_rcvdata)) &&
		    (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
			error = 0;
			NG_FREE_ITEM(item);
			break;
		}
		error = (*rcvdata)(hook, item);
		break;
	case NGQF_MESG:
		if (hook && NG_HOOK_NOT_VALID(hook)) {
			/*
			 * The hook has been zapped then we can't use it.
			 * Immediately drop its reference.
			 * The message may not need it.
			 */
			NG_HOOK_UNREF(hook);
			hook = NULL;
		}
		/*
		 * Similarly, if the node is a zombie there is
		 * nothing we can do with it, drop everything.