[PATCH net] stmmac: fix reception of 802.1ad Ethernet tagged frames

[Elad Nachman]

stmmac reception handler calls stmmac_rx_vlan() to strip the vlan before 
calling napi_gro_receive().

The function assumes VLAN tagged frames are always tagged with 802.1Q protocol,
and assigns ETH_P_8021Q to the skb by hard-coding the parameter on call to 
__vlan_hwaccel_put_tag() .

This causes packets not to be passed to the VLAN slave if it was created with 
802.1AD protocol
(ip link add link eth0 eth0.100 type vlan proto 802.1ad id 100).

This fix passes the protocol from the VLAN header into __vlan_hwaccel_put_tag()
instead of using the hard-coded value of ETH_P_8021Q.

Signed-off-by: Elad Nachman <el...@gilat.com>

---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c 
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b65e2d1..ced2d34 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3293,17 +3293,19 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, 
struct net_device *dev)
 
 static void stmmac_rx_vlan(struct net_device *dev, struct sk_buff *skb)
 {
-       struct ethhdr *ehdr;
+       struct vlan_ethhdr *veth;
        u16 vlanid;
+       __be16 vlan_proto;
 
        if ((dev->features & NETIF_F_HW_VLAN_CTAG_RX) ==
            NETIF_F_HW_VLAN_CTAG_RX &&
            !__vlan_get_tag(skb, &vlanid)) {
                /* pop the vlan tag */
-               ehdr = (struct ethhdr *)skb->data;
-               memmove(skb->data + VLAN_HLEN, ehdr, ETH_ALEN * 2);
+               veth = (struct vlan_ethhdr *)skb->data;
+               vlan_proto = veth->h_vlan_proto;
+               memmove(skb->data + VLAN_HLEN, veth, ETH_ALEN * 2);
                skb_pull(skb, VLAN_HLEN);
-               __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlanid);
+               __vlan_hwaccel_put_tag(skb, vlan_proto, vlanid);
        }
 }
 
-- 
2.7.4