NETLINK_CB(skb).dst_groups = XFRMGRP_SA;
static int xfrm_notify_sa_flush(struct km_event *c){	struct xfrm_usersa_flush *p;	struct nlmsghdr *nlh;	struct sk_buff *skb;	unsigned char *b;	int len = NLMSG_LENGTH(sizeof(struct xfrm_usersa_flush));	skb = alloc_skb(len, GFP_ATOMIC);	if (skb == NULL)		return -ENOMEM;	b = skb->tail;	nlh = NLMSG_PUT(skb, c->pid, c->seq,			XFRM_MSG_FLUSHSA, sizeof(*p));	nlh->nlmsg_flags = 0;	p = NLMSG_DATA(nlh);	p->proto = c->data.proto;	nlh->nlmsg_len = skb->tail - b;	return netlink_broadcast(xfrm_nl, skb, 0, XFRMGRP_SA, GFP_ATOMIC);nlmsg_failure:	kfree_skb(skb);	return -1;}