	rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
			      sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
			      orig_dport, sk);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		if (err == -ENETUNREACH)
			IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
		return err;
	}
…
	/* Socket identity is still unknown (sport may be zero).
	 * However we set state to SYN-SENT and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	tcp_set_state(sk, TCP_SYN_SENT);
	err = inet_hash_connect(tcp_death_row, sk);
	if (err)
		goto failure;
…
	if (likely(!tp->repair)) {
		union tcp_seq_and_ts_off st;

		st = secure_tcp_seq_and_ts_off(net,
					       inet->inet_saddr,
					       inet->inet_daddr,
					       inet->inet_sport,
					       usin->sin_port);
		if (!tp->write_seq)
			WRITE_ONCE(tp->write_seq, st.seq);
		WRITE_ONCE(tp->tsoffset, st.ts_off);
	}
…
	err = tcp_connect(sk);

	if (err)
		goto failure;

	return 0;

failure:
	/*
	 * This unhashes the socket and releases the local port,
	 * if necessary.
	 */
	tcp_set_state(sk, TCP_CLOSE);
	inet_bhash2_reset_saddr(sk);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
	inet->inet_dport = 0;
	return err;

Warm-up