net/ipv4/tcp_dctcp.h

0001 #ifndef _TCP_DCTCP_H
0002 #define _TCP_DCTCP_H
0003
0004 static inline void dctcp_ece_ack_cwr(struct sock *sk, u32 ce_state)
0005 {
0006     struct tcp_sock *tp = tcp_sk(sk);
0007
0008     if (ce_state == 1)
0009         tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
0010     else
0011         tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
0012 }
0013
0014 /* Minimal DCTP CE state machine:
0015  *
0016  * S:   0 <- last pkt was non-CE
0017  *  1 <- last pkt was CE
0018  */
0019 static inline void dctcp_ece_ack_update(struct sock *sk, enum tcp_ca_event evt,
0020                     u32 *prior_rcv_nxt, u32 *ce_state)
0021 {
0022     u32 new_ce_state = (evt == CA_EVENT_ECN_IS_CE) ? 1 : 0;
0023
0024     if (*ce_state != new_ce_state) {
0025         /* CE state has changed, force an immediate ACK to
0026          * reflect the new CE state. If an ACK was delayed,
0027          * send that first to reflect the prior CE state.
0028          */
0029         if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) {
0030             dctcp_ece_ack_cwr(sk, *ce_state);
0031             __tcp_send_ack(sk, *prior_rcv_nxt);
0032         }
0033         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW;
0034     }
0035     *prior_rcv_nxt = tcp_sk(sk)->rcv_nxt;
0036     *ce_state = new_ce_state;
0037     dctcp_ece_ack_cwr(sk, new_ce_state);
0038 }
0039
0040 #endif