xnu-3248.50.21.tar.gz

[apple/xnu.git] / bsd / netinet / tcp_input.c

diff --git a/bsd/netinet/tcp_input.c b/bsd/netinet/tcp_input.c
index 38e98861414f66a94fe409a2de42ae9ba454bfe9..24450b2762704efa85f1c8a962c4a05b0c84b8c4 100644 (file)
--- a/bsd/netinet/tcp_input.c
+++ b/bsd/netinet/tcp_input.c
@@ -152,6 +152,9 @@ struct tcphdr tcp_savetcp;
 #define DBG_FNC_TCP_INPUT       NETDBG_CODE(DBG_NETTCP, (3 << 8))
 #define DBG_FNC_TCP_NEWCONN     NETDBG_CODE(DBG_NETTCP, (7 << 8))
 
+#define        TCP_RTT_HISTORY_EXPIRE_TIME     (60 * TCP_RETRANSHZ)
+#define        TCP_RECV_THROTTLE_WIN   (5 * TCP_RETRANSHZ)
+
 tcp_cc tcp_ccgen;
 
 struct tcpstat tcpstat;
@@ -5161,12 +5164,17 @@ uint32_t
 get_base_rtt(struct tcpcb *tp) 
 {
        uint32_t base_rtt = 0, i;
-       for (i = 0; i < N_RTT_BASE; ++i) {
-               if (tp->rtt_hist[i] != 0 &&
-                       (base_rtt == 0 || tp->rtt_hist[i] < base_rtt))
-                       base_rtt = tp->rtt_hist[i];
+       struct rtentry *rt = tp->t_inpcb->inp_route.ro_rt;
+
+       if (rt != NULL) {
+               for (i = 0; i < NRTT_HIST; ++i) {
+                       if (rt->rtt_hist[i] != 0 &&
+                           (base_rtt == 0 || rt->rtt_hist[i] < base_rtt))
+                               base_rtt = rt->rtt_hist[i];
+               }
        }
-       return base_rtt;
+
+       return (base_rtt);
 }
 
 /* Each value of RTT base represents the minimum RTT seen in a minute.
@@ -5175,31 +5183,59 @@ get_base_rtt(struct tcpcb *tp)
 void
 update_base_rtt(struct tcpcb *tp, uint32_t rtt)
 {
-       int32_t i, qdelay;
        u_int32_t base_rtt;
+       struct rtentry *rt;
 
-       if (++tp->rtt_count >= rtt_samples_per_slot) {
+       if ((rt = tp->t_inpcb->inp_route.ro_rt) == NULL)
+               return;
+       if (rt->rtt_expire_ts == 0) {
+               RT_LOCK_SPIN(rt);
+               /* check again to avoid any race */
+               if (rt->rtt_expire_ts != 0) {
+                       RT_UNLOCK(rt);
+                       goto update;
+               }
+               rt->rtt_expire_ts = tcp_now;
+               rt->rtt_index = 0;
+               rt->rtt_hist[0] = rtt;
+               RT_UNLOCK(rt);
+               return;
+       }
+update:
 #if TRAFFIC_MGT
-               /*
-                * If the recv side is being throttled, check if the 
-                * current RTT is closer to the base RTT seen in 
-                * first (recent) two slots. If so, unthrottle the stream.
-                */
-               if (tp->t_flagsext & TF_RECV_THROTTLE) {
-                       base_rtt = min(tp->rtt_hist[0], tp->rtt_hist[1]);
-                       qdelay = tp->t_rttcur - base_rtt;
-                       if (qdelay < target_qdelay)
-                               tp->t_flagsext &= ~(TF_RECV_THROTTLE);
+       /*
+        * If the recv side is being throttled, check if the
+        * current RTT is closer to the base RTT seen in
+        * first (recent) two slots. If so, unthrottle the stream.
+        */
+       if ((tp->t_flagsext & TF_RECV_THROTTLE) &&
+           (int)(tcp_now - tp->t_recv_throttle_ts) >= TCP_RECV_THROTTLE_WIN) {
+               base_rtt = get_base_rtt(tp);
+               if (tp->t_rttcur <= (base_rtt + target_qdelay)) {
+                       tp->t_flagsext &= ~TF_RECV_THROTTLE;
+                       tp->t_recv_throttle_ts = 0;
                }
+       }
 #endif /* TRAFFIC_MGT */
-
-               for (i = (N_RTT_BASE-1); i > 0; --i) {
-                       tp->rtt_hist[i] = tp->rtt_hist[i-1];
+       if ((int)(tcp_now - rt->rtt_expire_ts) >=
+           TCP_RTT_HISTORY_EXPIRE_TIME) {
+               RT_LOCK_SPIN(rt);
+               /* check the condition again to avoid race */
+               if ((int)(tcp_now - rt->rtt_expire_ts) >=
+                   TCP_RTT_HISTORY_EXPIRE_TIME) {
+                       rt->rtt_index++;
+                       if (rt->rtt_index >= NRTT_HIST)
+                               rt->rtt_index = 0;
+                       rt->rtt_hist[rt->rtt_index] = rtt;
+                       rt->rtt_expire_ts = tcp_now;
+               } else {
+                       rt->rtt_hist[rt->rtt_index] =
+                           min(rt->rtt_hist[rt->rtt_index], rtt);
                }
-               tp->rtt_hist[0] = rtt;
-               tp->rtt_count = 0;
+               RT_UNLOCK(rt);
        } else {
-               tp->rtt_hist[0] = min(tp->rtt_hist[0], rtt);
+               rt->rtt_hist[rt->rtt_index] =
+                   min(rt->rtt_hist[rt->rtt_index], rtt);
        }
 }
 
@@ -5444,9 +5480,9 @@ tcp_mss(tp, offer, input_ifscope)
        int offer;
        unsigned int input_ifscope;
 {
-       register struct rtentry *rt;
+       struct rtentry *rt;
        struct ifnet *ifp;
-       register int rtt, mss;
+       int rtt, mss;
        u_int32_t bufsize;
        struct inpcb *inp;
        struct socket *so;