--- cci/sys/netinet/tcp_input.c	2019/07/28 12:24:19	1.1.1.1
+++ cci/sys/netinet/tcp_input.c	2019/07/28 12:29:38	1.1.1.2
@@ -67,7 +67,7 @@ tcp_input(m0)
 	short ostate;
 	struct in_addr laddr;
 	int dropsocket = 0;
-	struct ifnet *ifp;
+	struct ifnet *ifp, *ifnet;
 	struct ifnet *tcp_getif();
 	u_short	ifmss;
 
@@ -142,8 +142,8 @@ tcp_input(m0)
 	 * Drop TCP and IP headers.
 	 */
 	off += sizeof (struct ip);
-	m->m_off += off;
-	m->m_len -= off;
+	m->m_off += sizeof(struct tcpiphdr);
+	m->m_len -= sizeof(struct tcpiphdr);
 
 	/*
 	 * Convert TCP protocol specific fields to host format.
@@ -565,6 +565,22 @@ trimthenstep6:
 				tp->t_srtt =
 				    tcp_alpha * tp->t_srtt +
 				    (1 - tcp_alpha) * tp->t_rtt;
+			/*
+		 	* Kludge. We adjust the srtt value for x25/l2 interface
+		 	* or serial line to reduce the number of retries when 
+			* the line is loaded. The value is proportional to 
+			* the load, i.e., the route's reference count.
+		 	*/
+			if (tp->t_inpcb->inp_route.ro_rt) {
+				ifnet = tp->t_inpcb->inp_route.ro_rt->rt_ifp;
+				if (tp->t_srtt && 
+				    ifnet && 
+				    ifnet->if_name[0] == 's' && 
+				    (ifnet->if_name[1] == 'd' ||
+				     ifnet->if_name[1] == 'l')) {
+					tp->t_srtt += tp->t_inpcb->inp_route.ro_rt->rt_refcnt;
+				}
+			}
 			tp->t_rtt = 0;
 		}
 
@@ -574,6 +590,7 @@ trimthenstep6:
 			TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
 			    tcp_beta * tp->t_srtt, TCPTV_MIN, TCPTV_MAX);
 			tp->t_rtt = 1;
+			tp->t_rtseq = ti->ti_ack;
 			tp->t_rxtshift = 0;
 		}
 		if (acked > so->so_snd.sb_cc) {