--- zzzz-none-000/linux-4.1.38/net/ipv4/fib_frontend.c	2017-01-18 18:48:06.000000000 +0000
+++ bcm63-7582-715/linux-4.1.38/net/ipv4/fib_frontend.c	2020-11-25 10:06:48.000000000 +0000
@@ -379,6 +379,13 @@
 {
 	int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
 
+#if defined(CONFIG_BCM_KF_MCAST_RP_FILTER)
+	/* ignore rp_filter for multicast traffic */
+	if (skb->pkt_type == PACKET_MULTICAST) {
+		r = 0;
+	}
+#endif
+
 	if (!r && !fib_num_tclassid_users(dev_net(dev)) &&
 	    IN_DEV_ACCEPT_LOCAL(idev) &&
 	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {