1#ifndef _TCP_DCTCP_H
2#define _TCP_DCTCP_H
3
4static inline void dctcp_ece_ack_cwr(struct sock *sk, u32 ce_state)
5{
6	struct tcp_sock *tp = tcp_sk(sk);
7
8	if (ce_state == 1)
9		tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
10	else
11		tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
12}
13
14/* Minimal DCTP CE state machine:
15 *
16 * S:	0 <- last pkt was non-CE
17 *	1 <- last pkt was CE
18 */
19static inline void dctcp_ece_ack_update(struct sock *sk, enum tcp_ca_event evt,
20					u32 *prior_rcv_nxt, u32 *ce_state)
21{
22	u32 new_ce_state = (evt == CA_EVENT_ECN_IS_CE) ? 1 : 0;
23
24	if (*ce_state != new_ce_state) {
25		/* CE state has changed, force an immediate ACK to
26		 * reflect the new CE state. If an ACK was delayed,
27		 * send that first to reflect the prior CE state.
28		 */
29		if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
30			dctcp_ece_ack_cwr(sk, *ce_state);
31			__tcp_send_ack(sk, *prior_rcv_nxt);
32		}
33		inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
34	}
35	*prior_rcv_nxt = tcp_sk(sk)->rcv_nxt;
36	*ce_state = new_ce_state;
37	dctcp_ece_ack_cwr(sk, new_ce_state);
38}
39
40#endif
41