net: dsa: create a helper for locating EtherType DSA headers on TX

Create a similar helper for locating the offset to the DSA header
relative to skb->data, and make the existing EtherType header taggers to
use it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index ee194df68902..9ea637832ea9 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -521,6 +521,15 @@ static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)
 	return skb->data - 2;
 }
 
+/* On TX, skb->data points to skb_mac_header(skb), which means that EtherType
+ * header taggers start exactly where the EtherType is (the EtherType is
+ * treated as part of the DSA header).
+ */
+static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)
+{
+	return skb->data + 2 * ETH_ALEN;
+}
+
 /* switch.c */
 int dsa_switch_register_notifier(struct dsa_switch *ds);
 void dsa_switch_unregister_notifier(struct dsa_switch *ds);