+/* Events passed to congestion control interface */
+enum tcp_ca_event {
+ CA_EVENT_TX_START, /* first transmit when no packets in flight */
+ CA_EVENT_CWND_RESTART, /* congestion window restart */
+ CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
+ CA_EVENT_FRTO, /* fast recovery timeout */
+ CA_EVENT_LOSS, /* loss timeout */
+ CA_EVENT_FAST_ACK, /* in sequence ack */
+ CA_EVENT_SLOW_ACK, /* other ack */
+};
+
+/*
+ * Interface for adding new TCP congestion control handlers
+ */
+#define TCP_CA_NAME_MAX 16
+struct tcp_congestion_ops {
+ struct list_head list;
+
+ /* initialize private data (optional) */
+ void (*init)(struct tcp_sock *tp);
+ /* cleanup private data (optional) */
+ void (*release)(struct tcp_sock *tp);
+
+ /* return slow start threshold (required) */
+ u32 (*ssthresh)(struct tcp_sock *tp);
+ /* lower bound for congestion window (optional) */
+ u32 (*min_cwnd)(struct tcp_sock *tp);
+ /* do new cwnd calculation (required) */
+ void (*cong_avoid)(struct tcp_sock *tp, u32 ack,
+ u32 rtt, u32 in_flight, int good_ack);
+ /* round trip time sample per acked packet (optional) */
+ void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt);
+ /* call before changing ca_state (optional) */
+ void (*set_state)(struct tcp_sock *tp, u8 new_state);
+ /* call when cwnd event occurs (optional) */
+ void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev);
+ /* new value of cwnd after loss (optional) */
+ u32 (*undo_cwnd)(struct tcp_sock *tp);
+ /* hook for packet ack accounting (optional) */
+ void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked);
+ /* get info for tcp_diag (optional) */
+ void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb);
+
+ char name[TCP_CA_NAME_MAX];
+ struct module *owner;
+};
+
+extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
+extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
+
+extern void tcp_init_congestion_control(struct tcp_sock *tp);
+extern void tcp_cleanup_congestion_control(struct tcp_sock *tp);
+extern int tcp_set_default_congestion_control(const char *name);
+extern void tcp_get_default_congestion_control(char *name);
+
+extern struct tcp_congestion_ops tcp_reno;
+extern u32 tcp_reno_ssthresh(struct tcp_sock *tp);
+extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack,
+ u32 rtt, u32 in_flight, int flag);
+extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp);
+
+static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state)
+{
+ if (tp->ca_ops->set_state)
+ tp->ca_ops->set_state(tp, ca_state);
+ tp->ca_state = ca_state;
+}
+
+static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event)
+{
+ if (tp->ca_ops->cwnd_event)
+ tp->ca_ops->cwnd_event(tp, event);
+}
+