Function ng_con_nodes

freebsd/netgraph/ng_base.c:1477–1521

* Connect this node with another node. We assume that this node is * currently locked, as we are only called from an NGM_CONNECT message. */

 * currently locked, as we are only called from an NGM_CONNECT message.
 */
static int
ng_con_nodes(item_p item, node_p node, const char *name,
    node_p node2, const char *name2)
{
	int	error;
	hook_p	hook;
	hook_p	hook2;

	if (ng_findhook(node2, name2) != NULL) {
		return(EEXIST);
	}
	if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
		return (error);
	/* Allocate the other hook and link it up */
	NG_ALLOC_HOOK(hook2);
	if (hook2 == NULL) {
		TRAP_ERROR();
		ng_destroy_hook(hook);	/* XXX check ref counts so far */
		NG_HOOK_UNREF(hook);	/* including our ref */
		return (ENOMEM);
	}
	hook2->hk_refs = 1;		/* start with a reference for us. */
	hook2->hk_flags = HK_INVALID;
	hook2->hk_peer = hook;		/* Link the two together */
	hook->hk_peer = hook2;	
	NG_HOOK_REF(hook);		/* Add a ref for the peer to each*/
	NG_HOOK_REF(hook2);
	hook2->hk_node = &ng_deadnode;
	strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);

	/*
	 * Queue the function above.
	 * Procesing continues in that function in the lock context of
	 * the other node.
	 */
	if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
	    NG_NOFLAGS))) {
		printf("failed in ng_con_nodes(): %d\n", error);
		ng_destroy_hook(hook);	/* also zaps peer */
	}

	NG_HOOK_UNREF(hook);		/* Let each hook go if it wants to */
	NG_HOOK_UNREF(hook2);
	return (error);
}

/*
 * Make a peer and connect.