compat: Fix gre header bug

Commit 436d36d introduced a bug into the gre header build for gre and ip gre type tunnels. __vlan_hwaccel_push_inside does not check whether the vlan tag is even present. So check first and avoid padding space for a vlan tag that isn't present. Fixes: 436d36d ("compat: Fixups for newer kernels") Signed-off-by: Greg Rose <[email protected]> Acked-by: William Tu <[email protected]> Signed-off-by: Justin Pettit <[email protected]>
lhh · Jun 29, 2018 · 56174c2 · 56174c2
1 parent 4c0583d
commit 56174c2
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/datapath/linux/compat/ip_gre.c b/datapath/linux/compat/ip_gre.c
@@ -552,10 +552,12 @@ netdev_tx_t rpl_gre_fb_xmit(struct sk_buff *skb)
 			goto err_free_rt;
 	}
 
-	skb = __vlan_hwaccel_push_inside(skb);
-	if (unlikely(!skb)) {
-		err = -ENOMEM;
-		goto err_free_rt;
+	if (skb_vlan_tag_present(skb)) {
+		skb = __vlan_hwaccel_push_inside(skb);
+		if (unlikely(!skb)) {
+			err = -ENOMEM;
+			goto err_free_rt;
+		}
 	}
 
 	/* Push Tunnel header. */