core/dev: do not ignore dmac in dev_forward_skb()

commit 06a23fe31c
("core/dev: set pkt_type after eth_type_trans() in dev_forward_skb()")
and refactoring 64261f230a
("dev: move skb_scrub_packet() after eth_type_trans()")

are forcing pkt_type to be PACKET_HOST when skb traverses veth.

which means that ip forwarding will kick in inside netns
even if skb->eth->h_dest != dev->dev_addr

Fix order of eth_type_trans() and skb_scrub_packet() in dev_forward_skb()
and in ip_tunnel_rcv()

Fixes: 06a23fe31c ("core/dev: set pkt_type after eth_type_trans() in dev_forward_skb()")
CC: Isaku Yamahata <yamahatanetdev@gmail.com>
CC: Maciej Zenczykowski <zenczykowski@gmail.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1690,13 +1690,9 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
 		kfree_skb(skb);
 		return NET_RX_DROP;
 	}
-	skb->protocol = eth_type_trans(skb, dev);
 
-	/* eth_type_trans() can set pkt_type.
-	 * call skb_scrub_packet() after it to clear pkt_type _after_ calling
-	 * eth_type_trans().
-	 */
 	skb_scrub_packet(skb, true);
+	skb->protocol = eth_type_trans(skb, dev);
 
 	return netif_rx(skb);
 }

net/ipv4/ip_tunnel.c

@@ -454,6 +454,8 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 	tstats->rx_bytes += skb->len;
 	u64_stats_update_end(&tstats->syncp);
 
+	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
+
 	if (tunnel->dev->type == ARPHRD_ETHER) {
 		skb->protocol = eth_type_trans(skb, tunnel->dev);
 		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
@@ -461,8 +463,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 		skb->dev = tunnel->dev;
 	}
 
-	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
-
 	gro_cells_receive(&tunnel->gro_cells, skb);
 	return 0;