static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
			   u32 seq, u16 flags, int event, bool unicast)
{
	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
	struct tcf_block *block = chain->block;
	struct net *net = block->net;
	struct sk_buff *skb;
	int err = 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tc_chain_fill_node(chain->tmplt_ops, chain->tmplt_priv,
			       chain->index, net, skb, block, portid,
			       seq, flags, event) <= 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	if (unicast)
		err = rtnl_unicast(skb, net, portid);
	else
		err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
				     flags & NLM_F_ECHO);

	return err;
}