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From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	DENG Qingfang <dqfext@gmail.com>, John Crispin <john@phrozen.org>,
	Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>
Subject: [RFC PATCH net-next 1/4] net: dsa: create a helper that strips EtherType DSA headers on RX
Date: Mon,  9 Aug 2021 14:57:19 +0300	[thread overview]
Message-ID: <20210809115722.351383-2-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20210809115722.351383-1-vladimir.oltean@nxp.com>

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>
---
 net/dsa/dsa_priv.h    | 26 ++++++++++++++++++++++++++
 net/dsa/tag_brcm.c    | 10 ++--------
 net/dsa/tag_dsa.c     |  8 ++------
 net/dsa/tag_lan9303.c |  5 +++--
 net/dsa/tag_mtk.c     |  4 +---
 net/dsa/tag_qca.c     |  3 +--
 net/dsa/tag_rtl4_a.c  |  5 +----
 net/dsa/tag_sja1105.c |  4 +---
 8 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 9575cabd3ec3..8a12ec1f9d21 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);
diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index 96e93b544a0d..2fc546b31ad8 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -190,10 +190,7 @@ static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
 	if (!nskb)
 		return nskb;
 
-	/* Move the Ethernet DA and SA */
-	memmove(nskb->data - ETH_HLEN,
-		nskb->data - ETH_HLEN - BRCM_TAG_LEN,
-		2 * ETH_ALEN);
+	dsa_strip_etype_header(skb, BRCM_TAG_LEN);
 
 	return nskb;
 }
@@ -270,10 +267,7 @@ static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
 
 	dsa_default_offload_fwd_mark(skb);
 
-	/* Move the Ethernet DA and SA */
-	memmove(skb->data - ETH_HLEN,
-		skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN,
-		2 * ETH_ALEN);
+	dsa_strip_etype_header(skb, BRCM_LEG_TAG_LEN);
 
 	return skb;
 }
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index e32f8160e895..ad9c841c998f 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -312,14 +312,10 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
 		memcpy(dsa_header, new_header, DSA_HLEN);
 
 		if (extra)
-			memmove(skb->data - ETH_HLEN,
-				skb->data - ETH_HLEN - extra,
-				2 * ETH_ALEN);
+			dsa_strip_etype_header(skb, extra);
 	} else {
 		skb_pull_rcsum(skb, DSA_HLEN);
-		memmove(skb->data - ETH_HLEN,
-			skb->data - ETH_HLEN - DSA_HLEN - extra,
-			2 * ETH_ALEN);
+		dsa_strip_etype_header(skb, DSA_HLEN + extra);
 	}
 
 	return skb;
diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c
index 58d3a0e712d2..af13c0a9cb41 100644
--- a/net/dsa/tag_lan9303.c
+++ b/net/dsa/tag_lan9303.c
@@ -112,8 +112,9 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
 	 * and the current ethertype field.
 	 */
 	skb_pull_rcsum(skb, 2 + 2);
-	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
-		2 * ETH_ALEN);
+
+	dsa_strip_etype_header(skb, LAN9303_TAG_LEN);
+
 	if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU))
 		dsa_default_offload_fwd_mark(skb);
 
diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index bbf37c031d44..6a78e9f146e5 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -80,9 +80,7 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev)
 	/* Remove MTK tag and recalculate checksum. */
 	skb_pull_rcsum(skb, MTK_HDR_LEN);
 
-	memmove(skb->data - ETH_HLEN,
-		skb->data - ETH_HLEN - MTK_HDR_LEN,
-		2 * ETH_ALEN);
+	dsa_strip_etype_header(skb, MTK_HDR_LEN);
 
 	/* Get source port information */
 	port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK);
diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index 6e3136990491..f9fc881da591 100644
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -72,8 +72,7 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
 
 	/* 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);
+	dsa_strip_etype_header(skb, QCA_HDR_LEN);
 
 	/* Get source port information */
 	port = (hdr & QCA_HDR_RECV_SOURCE_PORT_MASK);
diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index aaddca3c0245..ff8707ff0c5b 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -108,10 +108,7 @@ static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb,
 	/* Remove RTL4 tag and recalculate checksum */
 	skb_pull_rcsum(skb, RTL4_A_HDR_LEN);
 
-	/* Move ethernet DA and SA in front of the data */
-	memmove(skb->data - ETH_HLEN,
-		skb->data - ETH_HLEN - RTL4_A_HDR_LEN,
-		2 * ETH_ALEN);
+	dsa_strip_etype_header(skb, RTL4_A_HDR_LEN);
 
 	dsa_default_offload_fwd_mark(skb);
 
diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index fc4cde775e50..5e8234079d08 100644
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -571,9 +571,7 @@ static struct sk_buff *sja1110_rcv_inband_control_extension(struct sk_buff *skb,
 	/* Advance skb->data past the DSA header */
 	skb_pull_rcsum(skb, SJA1110_HEADER_LEN);
 
-	/* Remove the DSA header */
-	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - SJA1110_HEADER_LEN,
-		2 * ETH_ALEN);
+	dsa_strip_etype_header(skb, SJA1110_HEADER_LEN);
 
 	/* With skb->data in its final place, update the MAC header
 	 * so that eth_hdr() continues to works properly.
-- 
2.25.1


  reply	other threads:[~2021-08-09 11:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-09 11:57 [RFC PATCH net-next 0/4] DSA tagger helpers Vladimir Oltean
2021-08-09 11:57 ` Vladimir Oltean [this message]
2021-08-10  1:01   ` [RFC PATCH net-next 1/4] net: dsa: create a helper that strips EtherType DSA headers on RX Andrew Lunn
2021-08-10  9:18   ` Florian Fainelli
2021-08-11 13:23   ` Linus Walleij
2021-08-09 11:57 ` [RFC PATCH net-next 2/4] net: dsa: create a helper which allocates space for EtherType DSA headers Vladimir Oltean
2021-08-10  1:03   ` Andrew Lunn
2021-08-10  9:21   ` Florian Fainelli
2021-08-11 13:24   ` Linus Walleij
2021-08-09 11:57 ` [RFC PATCH net-next 3/4] net: dsa: create a helper for locating EtherType DSA headers on RX Vladimir Oltean
2021-08-10  1:05   ` Andrew Lunn
2021-08-10  9:21   ` Florian Fainelli
2021-08-11 13:27   ` Linus Walleij
2021-08-09 11:57 ` [RFC PATCH net-next 4/4] net: dsa: create a helper for locating EtherType DSA headers on TX Vladimir Oltean
2021-08-10  1:07   ` Andrew Lunn
2021-08-10  9:22   ` Florian Fainelli
2021-08-11 13:28   ` Linus Walleij

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