diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -1172,7 +1172,19 @@
 	else
 		INP_RLOCK(inp);
 	NET_EPOCH_ENTER(et);
+#ifdef INET6
+	if ((flags & PRUS_IPV6) != 0) {
+		if ((inp->in6p_outputopts != NULL) &&
+		    (inp->in6p_outputopts->ip6po_tclass != -1))
+			tos = (u_char)inp->in6p_outputopts->ip6po_tclass;
+		else
+			tos = 0;
+	} else {
+		tos = inp->inp_ip_tos;
+	}
+#else
 	tos = inp->inp_ip_tos;
+#endif
 	if (control != NULL) {
 		/*
 		 * XXX: Currently, we assume all the optional information is