vrf: check the original netdevice for generating redirect

[ Upstream commit 2f17becfbea5e9a0529b51da7345783e96e69516 ]

Use the right device to determine if redirect should be sent especially
when using vrf. Same as well as when sending the redirect.

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3fe80e1..21f3bf2 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1538,6 +1538,12 @@
 	   ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
 	bool ret;
 
+	if (netif_is_l3_master(skb->dev)) {
+		dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
+		if (!dev)
+			return;
+	}
+
 	if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
 		ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
 			  dev->name);