int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
{
	struct sock *sk = skb->sk;
	struct inet_sock *inet = inet_sk(sk);
	struct ip_options_rcu *inet_opt;
	struct flowi4 *fl4;
	struct rtable *rt;
	struct iphdr *iph;
	int res;

	/* Skip all of this if the packet is already routed,
	 * f.e. by something like SCTP.
	 */
	rcu_read_lock();
	inet_opt = rcu_dereference(inet->inet_opt);
	fl4 = &fl->u.ip4;
	rt = skb_rtable(skb);
	if (rt != NULL)
		goto packet_routed;

	/* Make sure we can route this packet. */
	rt = (struct rtable *)__sk_dst_check(sk, 0);
	if (rt == NULL) {
		__be32 daddr;

		/* Use correct destination address if we have options. */
		daddr = inet->inet_daddr;
		if (inet_opt && inet_opt->opt.srr)
			daddr = inet_opt->opt.faddr;

		/* If this fails, retransmit mechanism of transport layer will
		 * keep trying until route appears or the connection times
		 * itself out.
		 */
		rt = ip_route_output_ports(sock_net(sk), fl4, sk,
					   daddr, inet->inet_saddr,
					   inet->inet_dport,
					   inet->inet_sport,
					   sk->sk_protocol,
					   RT_CONN_FLAGS(sk),
					   sk->sk_bound_dev_if);
		if (IS_ERR(rt))
			goto no_route;
		sk_setup_caps(sk, &rt->dst);
	}
	skb_dst_set_noref(skb, &rt->dst);

packet_routed:
	if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
		goto no_route;

	/* OK, we know where to send it, allocate and build IP header. */
	skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
	skb_reset_network_header(skb);
	iph = ip_hdr(skb);
	*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
	if (ip_dont_fragment(sk, &rt->dst) && !skb->local_df)
		iph->frag_off = htons(IP_DF);
	else
		iph->frag_off = 0;
	iph->ttl      = ip_select_ttl(inet, &rt->dst);
	iph->protocol = sk->sk_protocol;
	ip_copy_addrs(iph, fl4);

	/* Transport layer set skb->h.foo itself. */

	if (inet_opt && inet_opt->opt.optlen) {
		iph->ihl += inet_opt->opt.optlen >> 2;
		ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
	}

	ip_select_ident_more(skb, &rt->dst, sk,
			     (skb_shinfo(skb)->gso_segs ?: 1) - 1);

	skb->priority = sk->sk_priority;
	skb->mark = sk->sk_mark;

	res = ip_local_out(skb);
	rcu_read_unlock();
	return res;

no_route:
	rcu_read_unlock();
	IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
	kfree_skb(skb);
	return -EHOSTUNREACH;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.