LXR linux/net/ipv4/tcp

   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