1 files changed, 18 insertions, 4 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 86c109e2f2cd..0804b3e435c8 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -962,7 +962,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
         struct dccp_rx_hist_entry *packet;
         struct timeval now;
         u8 win_count;
-        u32 p_prev;
+        u32 p_prev, r_sample, t_elapsed;
         int ins;
 
         if (hcrx == NULL)
@@ -982,9 +982,23 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
                         break;
                 p_prev = hcrx->ccid3hcrx_rtt;
                 do_gettimeofday(&now);
-                hcrx->ccid3hcrx_rtt = timeval_usecs(&now) -
-                                     (opt_recv->dccpor_timestamp_echo -
-                                      opt_recv->dccpor_elapsed_time) * 10;
+                timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
+                r_sample = timeval_usecs(&now);
+                t_elapsed = opt_recv->dccpor_elapsed_time * 10;
+
+                if (unlikely(r_sample <= t_elapsed))
+                        LIMIT_NETDEBUG(KERN_WARNING
+                                       "%s: r_sample=%uus, t_elapsed=%uus\n",
+                                       __FUNCTION__, r_sample, t_elapsed);
+                else
+                        r_sample -= t_elapsed;
+
+                if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
+                        hcrx->ccid3hcrx_rtt = r_sample;
+                else
+                        hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
+                                              r_sample / 10;
+
                 if (p_prev != hcrx->ccid3hcrx_rtt)
                         ccid3_pr_debug("%s, New RTT=%luus, elapsed time=%u\n",
                                        dccp_role(sk), hcrx->ccid3hcrx_rtt,