Required TTL now calculated correctly.

Sources/mtrace/c/MTrace

@@ -369,6 +369,9 @@ void			k_hdr_include __P((int bool));
 void			k_set_ttl __P((int t));
 void			k_set_loop __P((int l));
 void			k_set_if __P((u_int32 ifa));
+#ifdef __riscos
+void			k_set_sleep __P((int s));
+#endif
 void			k_join __P((u_int32 grp, u_int32 ifa));
 void			k_leave __P((u_int32 grp, u_int32 ifa));
 char *			inet_fmt __P((u_int32 addr, char *s));
@@ -439,6 +442,9 @@ init_igmp()
     if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0)
 	log(LOG_ERR, errno, "IGMP socket");
 
+#ifdef __riscos
+    k_set_sleep(TRUE);		/* sleep taskwindows */
+#endif
     k_hdr_include(TRUE);	/* include IP header when sending */
     k_set_rcvbuf(48*1024);	/* lots of input buffering        */
     k_set_ttl(1);		/* restrict multicasts to one hop */
@@ -716,6 +722,16 @@ k_set_loop(l)
 	log(LOG_ERR, errno, "setsockopt IP_MULTICAST_LOOP %u", loop);
 }
 
+#ifdef __riscos
+void
+k_set_sleep(s)
+    int s;
+{
+    if (ioctl(igmp_socket, FIOSLEEPTW, &s) < 0)
+	log(LOG_ERR, errno, "ioctl FIOSLEEPTW %u", s);
+}
+#endif
+
 void
 k_set_if(ifa)
     u_int32 ifa;
@@ -3052,11 +3068,11 @@ or multicast at ttl %d doesn't reach its last-hop router for that source\n",
 
     printf("Round trip time %d ms; ", t_diff(base.rtime, base.qtime));
     {
-	struct tr_resp *n = base.resps + base.len - 1;
-	u_int ttl = n->tr_fttl + 1;
+	struct tr_resp *n = base.resps + base.len;
+	u_int ttl = 0;
 
-	rno = base.len - 1;
-	while (--rno > 0) {
+	rno = base.len;
+	while (--rno >= 0) {
 	    --n;
 	    ttl = MaX(ttl, MaX(1, n->tr_fttl) + base.len - rno);
 	}