xnu-3789.31.2.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 72f5f611cb4402908f2a084dd1c323e1b1b05655..2a48e2046de5b902cb097558959cc1073a91916d 100644 (file)
--- a/bsd/netinet/tcp_input.c
+++ b/bsd/netinet/tcp_input.c
@@ -5399,8 +5399,8 @@ tcp_compute_rtt(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th)
 }
 
 /*
- * Collect new round-trip time estimate
- * and update averages and current timeout.
+ * Collect new round-trip time estimate and update averages and
+ * current timeout.
  */
 static void
 tcp_xmit_timer(struct tcpcb *tp, int rtt,
@@ -5408,6 +5408,17 @@ tcp_xmit_timer(struct tcpcb *tp, int rtt,
 {
        int delta;
 
+       /*
+        * On AWDL interface, the initial RTT measurement on SYN
+        * can be wrong due to peer caching. Avoid the first RTT
+        * measurement as it might skew up the RTO.
+        * <rdar://problem/28739046>
+        */
+       if (tp->t_inpcb->inp_last_outifp != NULL &&
+           (tp->t_inpcb->inp_last_outifp->if_eflags & IFEF_AWDL) &&
+           th_ack == tp->iss + 1)
+               return;
+
        if (tp->t_flagsext & TF_RECOMPUTE_RTT) {
                if (SEQ_GT(th_ack, tp->snd_una) &&
                    SEQ_LEQ(th_ack, tp->snd_max) &&
@@ -5903,7 +5914,6 @@ tcp_newreno_partial_ack(struct tcpcb *tp, struct tcphdr *th)
                else
                        tp->snd_cwnd = 0;
                tp->snd_cwnd += tp->t_maxseg;
-
 }
 
 /*
@@ -5970,7 +5980,6 @@ tcp_dropdropablreq(struct socket *head)
                cur_cnt = 0;
        }
 
-
        qlen = head->so_incqlen;
        if (rnd == 0)
                rnd = RandomULong();
@@ -6022,7 +6031,6 @@ tcp_dropdropablreq(struct socket *head)
                        }
                }
                so = sonext;
-
        }
        if (so == NULL) {
                return (0);
@@ -6043,12 +6051,15 @@ found_victim:
        }
 
        TAILQ_REMOVE(&head->so_incomp, so, so_list);
+       head->so_incqlen--;
+       head->so_qlen--;
+       so->so_state &= ~SS_INCOMP;
+       so->so_flags |= SOF_OVERFLOW;
+       so->so_head = NULL;
        tcp_unlock(head, 0, 0);
 
        lck_mtx_assert(&inp->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
        tp = sototcpcb(so);
-       so->so_flags |= SOF_OVERFLOW;
-       so->so_head = NULL;
 
        tcp_close(tp);
        if (inp->inp_wantcnt > 0 && inp->inp_wantcnt != WNT_STOPUSING) {
@@ -6059,6 +6070,7 @@ found_victim:
                 * be garbage collected later.
                 * Release the reference held for so_incomp queue
                 */
+               VERIFY(so->so_usecount > 0);
                so->so_usecount--;
                tcp_unlock(so, 1, 0);
        } else {
@@ -6073,6 +6085,7 @@ found_victim:
 
                tcp_lock(so, 0, 0);
                /* Release the reference held for so_incomp queue */
+               VERIFY(so->so_usecount > 0);
                so->so_usecount--;
 
                if (so->so_usecount != 1 ||
@@ -6086,8 +6099,8 @@ found_victim:
                         */
                        tcp_unlock(so, 1, 0);
                } else {
-
                        /* Drop the reference held for this function */
+                       VERIFY(so->so_usecount > 0);
                        so->so_usecount--;
 
                        in_pcbdispose(inp);
@@ -6097,8 +6110,6 @@ found_victim:
        tcpstat.tcps_drops++;
 
        tcp_lock(head, 0, 0);
-       head->so_incqlen--;
-       head->so_qlen--;
        return(1);
 }