+static void
+tcp_estimate_initial_rtt (tcp_connection_t * tc)
+{
+ u8 thread_index = vlib_num_workers ()? 1 : 0;
+ int mrtt;
+
+ if (tc->rtt_ts)
+ {
+ tc->mrtt_us = tcp_time_now_us (thread_index) - tc->rtt_ts;
+ mrtt = clib_max ((u32) (tc->mrtt_us * THZ), 1);
+ tc->rtt_ts = 0;
+ }
+ else
+ {
+ mrtt = tcp_time_now_w_thread (thread_index) - tc->rcv_opts.tsecr;
+ tc->mrtt_us = (f64) mrtt *TCP_TICK;
+
+ }
+
+ if (mrtt > 0 && mrtt < TCP_RTT_MAX)
+ tcp_estimate_rtt (tc, mrtt);
+}
+