linux/net/ipv4/tcp_dctcp.h
Yuchung Cheng ffd177dea5 tcp: refactor DCTCP ECN ACK handling
DCTCP has two parts - a new ECN signalling mechanism and the response
function to it. The first part can be used by other congestion
control for DCTCP-ECN deployed networks. This patch moves that part
into a separate tcp_dctcp.h to be used by other congestion control
module (like how Yeah uses Vegas algorithmas). For example, BBR is
experimenting such ECN signal currently
https://tinyurl.com/ietf-102-iccrg-bbr2

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-10 22:26:00 -07:00

41 lines
1.0 KiB
C

#ifndef _TCP_DCTCP_H
#define _TCP_DCTCP_H
static inline void dctcp_ece_ack_cwr(struct sock *sk, u32 ce_state)
{
struct tcp_sock *tp = tcp_sk(sk);
if (ce_state == 1)
tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
else
tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
}
/* Minimal DCTP CE state machine:
*
* S: 0 <- last pkt was non-CE
* 1 <- last pkt was CE
*/
static inline void dctcp_ece_ack_update(struct sock *sk, enum tcp_ca_event evt,
u32 *prior_rcv_nxt, u32 *ce_state)
{
u32 new_ce_state = (evt == CA_EVENT_ECN_IS_CE) ? 1 : 0;
if (*ce_state != new_ce_state) {
/* CE state has changed, force an immediate ACK to
* reflect the new CE state. If an ACK was delayed,
* send that first to reflect the prior CE state.
*/
if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
dctcp_ece_ack_cwr(sk, *ce_state);
__tcp_send_ack(sk, *prior_rcv_nxt);
}
inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
}
*prior_rcv_nxt = tcp_sk(sk)->rcv_nxt;
*ce_state = new_ce_state;
dctcp_ece_ack_cwr(sk, new_ce_state);
}
#endif