net: vlan: introduce skb_vlan_eth_hdr()

Similar to skb_eth_hdr() introduced in commit 96cc4b6 ("macvlan: do
not assume mac_header is set in macvlan_broadcast()"), let's introduce a
skb_vlan_eth_hdr() helper which can be used in TX-only code paths to get
to the VLAN header based on skb->data rather than based on the
skb_mac_header(skb).

We also consolidate the drivers that dereference skb->data to go through
this helper.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: vladimiroltean

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

@@ -1935,8 +1935,7 @@ u16 bnx2x_select_queue(struct net_device *dev, struct sk_buff *skb,
 
 		/* Skip VLAN tag if present */
 		if (ether_type == ETH_P_8021Q) {
-			struct vlan_ethhdr *vhdr =
-				(struct vlan_ethhdr *)skb->data;
+			struct vlan_ethhdr *vhdr = skb_vlan_eth_hdr(skb);
 
 			ether_type = ntohs(vhdr->h_vlan_encapsulated_proto);
 		}

drivers/net/ethernet/emulex/benet/be_main.c

@@ -1124,7 +1124,7 @@ static struct sk_buff *be_lancer_xmit_workarounds(struct be_adapter *adapter,
 						  struct be_wrb_params
 						  *wrb_params)
 {
-	struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
+	struct vlan_ethhdr *veh = skb_vlan_eth_hdr(skb);
 	unsigned int eth_hdr_len;
 	struct iphdr *ip;
 

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -1532,7 +1532,7 @@ static int hns3_handle_vtags(struct hns3_enet_ring *tx_ring,
 	if (unlikely(rc < 0))
 		return rc;
 
-	vhdr = (struct vlan_ethhdr *)skb->data;
+	vhdr = skb_vlan_eth_hdr(skb);
 	vhdr->h_vlan_TCI |= cpu_to_be16((skb->priority << VLAN_PRIO_SHIFT)
 					 & VLAN_PRIO_MASK);
 

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -3063,7 +3063,7 @@ static inline int i40e_tx_prepare_vlan_flags(struct sk_buff *skb,
 			rc = skb_cow_head(skb, 0);
 			if (rc < 0)
 				return rc;
-			vhdr = (struct vlan_ethhdr *)skb->data;
+			vhdr = skb_vlan_eth_hdr(skb);
 			vhdr->h_vlan_TCI = htons(tx_flags >>
 						 I40E_TX_FLAGS_VLAN_SHIFT);
 		} else {

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -8798,7 +8798,7 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
 
 			if (skb_cow_head(skb, 0))
 				goto out_drop;
-			vhdr = (struct vlan_ethhdr *)skb->data;
+			vhdr = skb_vlan_eth_hdr(skb);
 			vhdr->h_vlan_TCI = htons(tx_flags >>
 						 IXGBE_TX_FLAGS_VLAN_SHIFT);
 		} else {

drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c

@@ -1854,7 +1854,7 @@ netxen_tso_check(struct net_device *netdev,
 
 	if (protocol == cpu_to_be16(ETH_P_8021Q)) {
 
-		vh = (struct vlan_ethhdr *)skb->data;
+		vh = skb_vlan_eth_hdr(skb);
 		protocol = vh->h_vlan_encapsulated_proto;
 		flags = FLAGS_VLAN_TAGGED;
 

drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c

@@ -318,7 +318,7 @@ static void qlcnic_send_filter(struct qlcnic_adapter *adapter,
 
 	if (adapter->flags & QLCNIC_VLAN_FILTERING) {
 		if (protocol == ETH_P_8021Q) {
-			vh = (struct vlan_ethhdr *)skb->data;
+			vh = skb_vlan_eth_hdr(skb);
 			vlan_id = ntohs(vh->h_vlan_TCI);
 		} else if (skb_vlan_tag_present(skb)) {
 			vlan_id = skb_vlan_tag_get(skb);
@@ -468,7 +468,7 @@ static int qlcnic_tx_pkt(struct qlcnic_adapter *adapter,
 	u32 producer = tx_ring->producer;
 
 	if (protocol == ETH_P_8021Q) {
-		vh = (struct vlan_ethhdr *)skb->data;
+		vh = skb_vlan_eth_hdr(skb);
 		flags = QLCNIC_FLAGS_VLAN_TAGGED;
 		vlan_tci = ntohs(vh->h_vlan_TCI);
 		protocol = ntohs(vh->h_vlan_encapsulated_proto);

drivers/net/ethernet/sfc/tx_tso.c

@@ -147,7 +147,7 @@ static __be16 efx_tso_check_protocol(struct sk_buff *skb)
 	EFX_WARN_ON_ONCE_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
 				  protocol);
 	if (protocol == htons(ETH_P_8021Q)) {
-		struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
+		struct vlan_ethhdr *veh = skb_vlan_eth_hdr(skb);
 
 		protocol = veh->h_vlan_encapsulated_proto;
 	}

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -4569,13 +4569,10 @@ 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 vlan_ethhdr *veth;
-	__be16 vlan_proto;
+	struct vlan_ethhdr *veth = skb_vlan_eth_hdr(skb);
+	__be16 vlan_proto = veth->h_vlan_proto;
 	u16 vlanid;
 
-	veth = (struct vlan_ethhdr *)skb->data;
-	vlan_proto = veth->h_vlan_proto;
-
 	if ((vlan_proto == htons(ETH_P_8021Q) &&
 	     dev->features & NETIF_F_HW_VLAN_CTAG_RX) ||
 	    (vlan_proto == htons(ETH_P_8021AD) &&

drivers/staging/gdm724x/gdm_lte.c

@@ -349,7 +349,7 @@ static s32 gdm_lte_tx_nic_type(struct net_device *dev, struct sk_buff *skb)
 	/* Get ethernet protocol */
 	eth = (struct ethhdr *)skb->data;
 	if (ntohs(eth->h_proto) == ETH_P_8021Q) {
-		vlan_eth = (struct vlan_ethhdr *)skb->data;
+		vlan_eth = skb_vlan_eth_hdr(skb);
 		mac_proto = ntohs(vlan_eth->h_vlan_encapsulated_proto);
 		network_data = skb->data + VLAN_ETH_HLEN;
 		nic_type |= NIC_TYPE_F_VLAN;
@@ -435,7 +435,7 @@ static netdev_tx_t gdm_lte_tx(struct sk_buff *skb, struct net_device *dev)
 	 * driver based on the NIC mac
 	 */
 	if (nic_type & NIC_TYPE_F_VLAN) {
-		struct vlan_ethhdr *vlan_eth = (struct vlan_ethhdr *)skb->data;
+		struct vlan_ethhdr *vlan_eth = skb_vlan_eth_hdr(skb);
 
 		nic->vlan_id = ntohs(vlan_eth->h_vlan_TCI) & VLAN_VID_MASK;
 		data_buf = skb->data + (VLAN_ETH_HLEN - ETH_HLEN);