net: dsa: create a helper that strips EtherType DSA headers on RX
All header taggers open-code a memmove that is fairly not all that
obvious, and we can hide the details behind a helper function, since the
only thing specific to the driver is the length of the header tag.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 9575cab..8a12ec1 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -452,6 +452,32 @@ static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb)
skb->offload_fwd_mark = !!(dp->bridge_dev);
}
+/* Helper for removing DSA header tags from packets in the RX path.
+ * Must not be called before skb_pull(len).
+ * skb->data
+ * |
+ * v
+ * | | | | | | | | | | | | | | | | | | |
+ * +-----------------------+-----------------------+---------------+-------+
+ * | Destination MAC | Source MAC | DSA header | EType |
+ * +-----------------------+-----------------------+---------------+-------+
+ * | |
+ * <----- len -----> <----- len ----->
+ * |
+ * >>>>>>> v
+ * >>>>>>> | | | | | | | | | | | | | | |
+ * >>>>>>> +-----------------------+-----------------------+-------+
+ * >>>>>>> | Destination MAC | Source MAC | EType |
+ * +-----------------------+-----------------------+-------+
+ * ^
+ * |
+ * skb->data
+ */
+static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
+{
+ memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
+}
+
/* switch.c */
int dsa_switch_register_notifier(struct dsa_switch *ds);
void dsa_switch_unregister_notifier(struct dsa_switch *ds);
