[PATCH RFC net-next 18/19] net: dsa: tag_qca: split out common tag accessors

[Alexander Lobakin]

...to make them available for the upcoming GRO callbacks.

Signed-off-by: Alexander Lobakin <alobakin@xxxxxxxx>
---
 net/dsa/tag_qca.c | 45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index 8939abce36d7..bee2788e034d 100644
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -28,6 +28,27 @@
 #define QCA_HDR_XMIT_FROM_CPU		BIT(7)
 #define QCA_HDR_XMIT_DP(port)		FIELD_PREP(GENMASK(6, 0), BIT(port))
 
+static inline bool qca_tag_sanity_check(const u8 *data)
+{
+	/* The QCA header is added by the switch between src addr and Ethertype
+	 * At this point, skb->data points to ethertype so header should be
+	 * right before
+	 */
+	u16 hdr = ntohs(*(__be16 *)(data - 2));
+
+	return QCA_HDR_RECV_VERSION(hdr) == QCA_HDR_VERSION;
+}
+
+static inline int qca_tag_source_port(const u8 *data)
+{
+	return *(data - 1) & QCA_HDR_RECV_SOURCE_PORT_MASK;
+}
+
+static inline __be16 qca_tag_encap_proto(const u8 *data)
+{
+	return *(__be16 *)data;
+}
+
 static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	const struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -55,34 +76,26 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 				   struct packet_type *pt)
 {
 	int port;
-	__be16 *phdr, hdr;
 
 	if (unlikely(!pskb_may_pull(skb, QCA_HDR_LEN)))
 		return NULL;
 
-	/* The QCA header is added by the switch between src addr and Ethertype
-	 * At this point, skb->data points to ethertype so header should be
-	 * right before
-	 */
-	phdr = (__be16 *)(skb->data - 2);
-	hdr = ntohs(*phdr);
-
 	/* Make sure the version is correct */
-	if (unlikely(QCA_HDR_RECV_VERSION(hdr) != QCA_HDR_VERSION))
+	if (unlikely(!qca_tag_sanity_check(skb->data)))
 		return NULL;
 
-	/* Remove QCA tag and recalculate checksum */
-	skb_pull_rcsum(skb, QCA_HDR_LEN);
-	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
-		ETH_HLEN - QCA_HDR_LEN);
-
 	/* Get source port information */
-	port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
+	port = qca_tag_source_port(skb->data);
 
 	skb->dev = dsa_master_find_slave(dev, 0, port);
 	if (!skb->dev)
 		return NULL;
 
+	/* Remove QCA tag and recalculate checksum */
+	skb_pull_rcsum(skb, QCA_HDR_LEN);
+	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - QCA_HDR_LEN,
+		ETH_HLEN - QCA_HDR_LEN);
+
 	return skb;
 }
 
@@ -90,7 +103,7 @@ static void qca_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto,
 				 int *offset)
 {
 	*offset = QCA_HDR_LEN;
-	*proto = ((__be16 *)skb->data)[0];
+	*proto = qca_tag_encap_proto(skb->data);
 }
 
 static const struct dsa_device_ops qca_netdev_ops = {
-- 
2.24.1