Merge branch 'net-dsa-tag_dsa-unify-regular-and-ethertype-dsa-taggers'

Tobias Waldekranz says:

====================
net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

The first patch ports tag_edsa.c's handling of IGMP/MLD traps to
tag_dsa.c. That way, we start from two logically equivalent taggers
that are then merged. The second commit does the heavy lifting of
actually fusing tag_dsa.c and tag_edsa.c. The final one just follows
up with some clean up of existing comments.

v2 -> v3:
  - Add the first patch described above as suggested by Andrew.
  - Better documentation of TO_SNIFFER and FORWARD tags.
  - Spelling.

v1 -> v2:
  - Fixed some grammar and whitespace errors.
  - Removed unnecessary default value in Kconfig.
  - Removed unnecessary #ifdef.
  - Split out comment fixes from functional changes.
  - Fully document enum dsa_code.
====================

Link: https://lore.kernel.org/r/20201114234558.31203-1-tobias@waldekranz.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/dsa/Kconfig

@@ -68,14 +68,19 @@ config NET_DSA_TAG_GSWIP
 	  Say Y or M if you want to enable support for tagging frames for the
 	  Lantiq / Intel GSWIP switches.
 
+config NET_DSA_TAG_DSA_COMMON
+	tristate
+
 config NET_DSA_TAG_DSA
 	tristate "Tag driver for Marvell switches using DSA headers"
+	select NET_DSA_TAG_DSA_COMMON
 	help
 	  Say Y or M if you want to enable support for tagging frames for the
 	  Marvell switches which use DSA headers.
 
 config NET_DSA_TAG_EDSA
 	tristate "Tag driver for Marvell switches using EtherType DSA headers"
+	select NET_DSA_TAG_DSA_COMMON
 	help
 	  Say Y or M if you want to enable support for tagging frames for the
 	  Marvell switches which use EtherType DSA headers.

net/dsa/Makefile

@@ -7,8 +7,7 @@ dsa_core-y += dsa.o dsa2.o master.o port.o slave.o switch.o
 obj-$(CONFIG_NET_DSA_TAG_8021Q) += tag_8021q.o
 obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
 obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
-obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
-obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
+obj-$(CONFIG_NET_DSA_TAG_DSA_COMMON) += tag_dsa.o
 obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
 obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
 obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o

net/dsa/tag_dsa.c

 // SPDX-License-Identifier: GPL-2.0+
 /*
- * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
+ * Regular and Ethertype DSA tagging
  * Copyright (c) 2008-2009 Marvell Semiconductor
+ *
+ * Regular DSA
+ * -----------
+
+ * For untagged (in 802.1Q terms) packets, the switch will splice in
+ * the tag between the SA and the ethertype of the original
+ * packet. Tagged frames will instead have their outermost .1Q tag
+ * converted to a DSA tag. It expects the same layout when receiving
+ * packets from the CPU.
+ *
+ * Example:
+ *
+ *     .----.----.----.---------
+ * Pu: | DA | SA | ET | Payload ...
+ *     '----'----'----'---------
+ *       6    6    2       N
+ *     .----.----.--------.-----.----.---------
+ * Pt: | DA | SA | 0x8100 | TCI | ET | Payload ...
+ *     '----'----'--------'-----'----'---------
+ *       6    6       2      2    2       N
+ *     .----.----.-----.----.---------
+ * Pd: | DA | SA | DSA | ET | Payload ...
+ *     '----'----'-----'----'---------
+ *       6    6     4    2       N
+ *
+ * No matter if a packet is received untagged (Pu) or tagged (Pt),
+ * they will both have the same layout (Pd) when they are sent to the
+ * CPU. This is done by ignoring 802.3, replacing the ethertype field
+ * with more metadata, among which is a bit to signal if the original
+ * packet was tagged or not.
+ *
+ * Ethertype DSA
+ * -------------
+ * Uses the exact same tag format as regular DSA, but also includes a
+ * proper ethertype field (which the mv88e6xxx driver sets to
+ * ETH_P_EDSA/0xdada) followed by two zero bytes:
+ *
+ * .----.----.--------.--------.-----.----.---------
+ * | DA | SA | 0xdada | 0x0000 | DSA | ET | Payload ...
+ * '----'----'--------'--------'-----'----'---------
+ *   6    6       2        2      4    2       N
  */
 
 #include <linux/etherdevice.h>
@@ -12,41 +53,104 @@
 
 #define DSA_HLEN	4
 
-static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
+/**
+ * enum dsa_cmd - DSA Command
+ * @DSA_CMD_TO_CPU: Set on packets that were trapped or mirrored to
+ *     the CPU port. This is needed to implement control protocols,
+ *     e.g. STP and LLDP, that must not allow those control packets to
+ *     be switched according to the normal rules.
+ * @DSA_CMD_FROM_CPU: Used by the CPU to send a packet to a specific
+ *     port, ignoring all the barriers that the switch normally
+ *     enforces (VLANs, STP port states etc.). No source address
+ *     learning takes place. "sudo send packet"
+ * @DSA_CMD_TO_SNIFFER: Set on the copies of packets that matched some
+ *     user configured ingress or egress monitor criteria. These are
+ *     forwarded by the switch tree to the user configured ingress or
+ *     egress monitor port, which can be set to the CPU port or a
+ *     regular port. If the destination is a regular port, the tag
+ *     will be removed before egressing the port. If the destination
+ *     is the CPU port, the tag will not be removed.
+ * @DSA_CMD_FORWARD: This tag is used on all bulk traffic passing
+ *     through the switch tree, including the flows that are directed
+ *     towards the CPU. Its device/port tuple encodes the original
+ *     source port on which the packet ingressed. It can also be used
+ *     on transmit by the CPU to defer the forwarding decision to the
+ *     hardware, based on the current config of PVT/VTU/ATU
+ *     etc. Source address learning takes places if enabled on the
+ *     receiving DSA/CPU port.
+ */
+enum dsa_cmd {
+	DSA_CMD_TO_CPU     = 0,
+	DSA_CMD_FROM_CPU   = 1,
+	DSA_CMD_TO_SNIFFER = 2,
+	DSA_CMD_FORWARD    = 3
+};
+
+/**
+ * enum dsa_code - TO_CPU Code
+ *
+ * @DSA_CODE_MGMT_TRAP: DA was classified as a management
+ *     address. Typical examples include STP BPDUs and LLDP.
+ * @DSA_CODE_FRAME2REG: Response to a "remote management" request.
+ * @DSA_CODE_IGMP_MLD_TRAP: IGMP/MLD signaling.
+ * @DSA_CODE_POLICY_TRAP: Frame matched some policy configuration on
+ *     the device. Typical examples are matching on DA/SA/VID and DHCP
+ *     snooping.
+ * @DSA_CODE_ARP_MIRROR: The name says it all really.
+ * @DSA_CODE_POLICY_MIRROR: Same as @DSA_CODE_POLICY_TRAP, but the
+ *     particular policy was set to trigger a mirror instead of a
+ *     trap.
+ * @DSA_CODE_RESERVED_6: Unused on all devices up to at least 6393X.
+ * @DSA_CODE_RESERVED_7: Unused on all devices up to at least 6393X.
+ *
+ * A 3-bit code is used to relay why a particular frame was sent to
+ * the CPU. We only use this to determine if the packet was mirrored
+ * or trapped, i.e. whether the packet has been forwarded by hardware
+ * or not.
+ *
+ * This is the superset of all possible codes. Any particular device
+ * may only implement a subset.
+ */
+enum dsa_code {
+	DSA_CODE_MGMT_TRAP     = 0,
+	DSA_CODE_FRAME2REG     = 1,
+	DSA_CODE_IGMP_MLD_TRAP = 2,
+	DSA_CODE_POLICY_TRAP   = 3,
+	DSA_CODE_ARP_MIRROR    = 4,
+	DSA_CODE_POLICY_MIRROR = 5,
+	DSA_CODE_RESERVED_6    = 6,
+	DSA_CODE_RESERVED_7    = 7
+};
+
+static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
+				   u8 extra)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
 	u8 *dsa_header;
 
-	/*
-	 * Convert the outermost 802.1q tag to a DSA tag for tagged
-	 * packets, or insert a DSA tag between the addresses and
-	 * the ethertype field for untagged packets.
-	 */
 	if (skb->protocol == htons(ETH_P_8021Q)) {
-		/*
-		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
-		 */
-		dsa_header = skb->data + 2 * ETH_ALEN;
-		dsa_header[0] = 0x60 | dp->ds->index;
+		if (extra) {
+			skb_push(skb, extra);
+			memmove(skb->data, skb->data + extra, 2 * ETH_ALEN);
+		}
+
+		/* Construct tagged FROM_CPU DSA tag from 802.1Q tag. */
+		dsa_header = skb->data + 2 * ETH_ALEN + extra;
+		dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | 0x20 | dp->ds->index;
 		dsa_header[1] = dp->index << 3;
 
-		/*
-		 * Move CFI field from byte 2 to byte 1.
-		 */
+		/* Move CFI field from byte 2 to byte 1. */
 		if (dsa_header[2] & 0x10) {
 			dsa_header[1] |= 0x01;
 			dsa_header[2] &= ~0x10;
 		}
 	} else {
-		skb_push(skb, DSA_HLEN);
-
-		memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
+		skb_push(skb, DSA_HLEN + extra);
+		memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);
 
-		/*
-		 * Construct untagged FROM_CPU DSA tag.
-		 */
-		dsa_header = skb->data + 2 * ETH_ALEN;
-		dsa_header[0] = 0x40 | dp->ds->index;
+		/* Construct untagged FROM_CPU DSA tag. */
+		dsa_header = skb->data + 2 * ETH_ALEN + extra;
+		dsa_header[0] = (DSA_CMD_FROM_CPU << 6) | dp->ds->index;
 		dsa_header[1] = dp->index << 3;
 		dsa_header[2] = 0x00;
 		dsa_header[3] = 0x00;
@@ -55,30 +159,60 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
 	return skb;
 }
 
-static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
-			       struct packet_type *pt)
+static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
+				  u8 extra)
 {
+	int source_device, source_port;
+	enum dsa_code code;
+	enum dsa_cmd cmd;
 	u8 *dsa_header;
-	int source_device;
-	int source_port;
 
-	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
-		return NULL;
-
-	/*
-	 * The ethertype field is part of the DSA header.
-	 */
+	/* The ethertype field is part of the DSA header. */
 	dsa_header = skb->data - 2;
 
-	/*
-	 * Check that frame type is either TO_CPU or FORWARD.
-	 */
-	if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0)
+	cmd = dsa_header[0] >> 6;
+	switch (cmd) {
+	case DSA_CMD_FORWARD:
+		skb->offload_fwd_mark = 1;
+		break;
+
+	case DSA_CMD_TO_CPU:
+		code = (dsa_header[1] & 0x6) | ((dsa_header[2] >> 4) & 1);
+
+		switch (code) {
+		case DSA_CODE_FRAME2REG:
+			/* Remote management is not implemented yet,
+			 * drop.
+			 */
+			return NULL;
+		case DSA_CODE_ARP_MIRROR:
+		case DSA_CODE_POLICY_MIRROR:
+			/* Mark mirrored packets to notify any upper
+			 * device (like a bridge) that forwarding has
+			 * already been done by hardware.
+			 */
+			skb->offload_fwd_mark = 1;
+			break;
+		case DSA_CODE_MGMT_TRAP:
+		case DSA_CODE_IGMP_MLD_TRAP:
+		case DSA_CODE_POLICY_TRAP:
+			/* Traps have, by definition, not been
+			 * forwarded by hardware, so don't mark them.
+			 */
+			break;
+		default:
+			/* Reserved code, this could be anything. Drop
+			 * seems like the safest option.
+			 */
+			return NULL;
+		}
+
+		break;
+
+	default:
 		return NULL;
+	}
 
-	/*
-	 * Determine source device and port.
-	 */
 	source_device = dsa_header[0] & 0x1f;
 	source_port = (dsa_header[1] >> 3) & 0x1f;
 
@@ -86,16 +220,15 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (!skb->dev)
 		return NULL;
 
-	/*
-	 * Convert the DSA header to an 802.1q header if the 'tagged'
-	 * bit in the DSA header is set.  If the 'tagged' bit is clear,
-	 * delete the DSA header entirely.
+	/* If the 'tagged' bit is set; convert the DSA tag to a 802.1Q
+	 * tag, and delete the ethertype (extra) if applicable. If the
+	 * 'tagged' bit is cleared; delete the DSA tag, and ethertype
+	 * if applicable.
 	 */
 	if (dsa_header[0] & 0x20) {
 		u8 new_header[4];
 
-		/*
-		 * Insert 802.1q ethertype and copy the VLAN-related
+		/* Insert 802.1Q ethertype and copy the VLAN-related
 		 * fields, but clear the bit that will hold CFI (since
 		 * DSA uses that bit location for another purpose).
 		 */
@@ -104,16 +237,13 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 		new_header[2] = dsa_header[2] & ~0x10;
 		new_header[3] = dsa_header[3];
 
-		/*
-		 * Move CFI bit from its place in the DSA header to
-		 * its 802.1q-designated place.
+		/* Move CFI bit from its place in the DSA header to
+		 * its 802.1Q-designated place.
 		 */
 		if (dsa_header[1] & 0x01)
 			new_header[2] |= 0x10;
 
-		/*
-		 * Update packet checksum if skb is CHECKSUM_COMPLETE.
-		 */
+		/* Update packet checksum if skb is CHECKSUM_COMPLETE. */
 		if (skb->ip_summed == CHECKSUM_COMPLETE) {
 			__wsum c = skb->csum;
 			c = csum_add(c, csum_partial(new_header + 2, 2, 0));
@@ -122,30 +252,101 @@ static struct sk_buff *dsa_rcv(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);
 	} else {
-		/*
-		 * Remove DSA tag and update checksum.
-		 */
 		skb_pull_rcsum(skb, DSA_HLEN);
 		memmove(skb->data - ETH_HLEN,
-			skb->data - ETH_HLEN - DSA_HLEN,
+			skb->data - ETH_HLEN - DSA_HLEN - extra,
 			2 * ETH_ALEN);
 	}
 
-	skb->offload_fwd_mark = 1;
-
 	return skb;
 }
 
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA)
+
+static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	return dsa_xmit_ll(skb, dev, 0);
+}
+
+static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
+			       struct packet_type *pt)
+{
+	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
+		return NULL;
+
+	return dsa_rcv_ll(skb, dev, 0);
+}
+
 static const struct dsa_device_ops dsa_netdev_ops = {
-	.name	= "dsa",
-	.proto	= DSA_TAG_PROTO_DSA,
-	.xmit	= dsa_xmit,
-	.rcv	= dsa_rcv,
+	.name	  = "dsa",
+	.proto	  = DSA_TAG_PROTO_DSA,
+	.xmit	  = dsa_xmit,
+	.rcv	  = dsa_rcv,
 	.overhead = DSA_HLEN,
 };
 
-MODULE_LICENSE("GPL");
+DSA_TAG_DRIVER(dsa_netdev_ops);
 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_DSA);
+#endif	/* CONFIG_NET_DSA_TAG_DSA */
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA)
+
+#define EDSA_HLEN 8
+
+static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	u8 *edsa_header;
+
+	skb = dsa_xmit_ll(skb, dev, EDSA_HLEN - DSA_HLEN);
+	if (!skb)
+		return NULL;
 
-module_dsa_tag_driver(dsa_netdev_ops);
+	edsa_header = skb->data + 2 * ETH_ALEN;
+	edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
+	edsa_header[1] = ETH_P_EDSA & 0xff;
+	edsa_header[2] = 0x00;
+	edsa_header[3] = 0x00;
+	return skb;
+}
+
+static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
+				struct packet_type *pt)
+{
+	if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
+		return NULL;
+
+	skb_pull_rcsum(skb, EDSA_HLEN - DSA_HLEN);
+
+	return dsa_rcv_ll(skb, dev, EDSA_HLEN - DSA_HLEN);
+}
+
+static const struct dsa_device_ops edsa_netdev_ops = {
+	.name	  = "edsa",
+	.proto	  = DSA_TAG_PROTO_EDSA,
+	.xmit	  = edsa_xmit,
+	.rcv	  = edsa_rcv,
+	.overhead = EDSA_HLEN,
+};
+
+DSA_TAG_DRIVER(edsa_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA);
+#endif	/* CONFIG_NET_DSA_TAG_EDSA */
+
+static struct dsa_tag_driver *dsa_tag_drivers[] = {
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_DSA)
+	&DSA_TAG_DRIVER_NAME(dsa_netdev_ops),
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_EDSA)
+	&DSA_TAG_DRIVER_NAME(edsa_netdev_ops),
+#endif
+};
+
+module_dsa_tag_drivers(dsa_tag_drivers);
+
+MODULE_LICENSE("GPL");

net/dsa/tag_edsa.c

-// SPDX-License-Identifier: GPL-2.0+
-/*
- * net/dsa/tag_edsa.c - Ethertype DSA tagging
- * Copyright (c) 2008-2009 Marvell Semiconductor
- */
-
-#include <linux/etherdevice.h>
-#include <linux/list.h>
-#include <linux/slab.h>
-
-#include "dsa_priv.h"
-
-#define DSA_HLEN	4
-#define EDSA_HLEN	8
-
-#define FRAME_TYPE_TO_CPU	0x00
-#define FRAME_TYPE_FORWARD	0x03
-
-#define TO_CPU_CODE_MGMT_TRAP		0x00
-#define TO_CPU_CODE_FRAME2REG		0x01
-#define TO_CPU_CODE_IGMP_MLD_TRAP	0x02
-#define TO_CPU_CODE_POLICY_TRAP		0x03
-#define TO_CPU_CODE_ARP_MIRROR		0x04
-#define TO_CPU_CODE_POLICY_MIRROR	0x05
-
-static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	u8 *edsa_header;
-
-	/*
-	 * Convert the outermost 802.1q tag to a DSA tag and prepend
-	 * a DSA ethertype field is the packet is tagged, or insert
-	 * a DSA ethertype plus DSA tag between the addresses and the
-	 * current ethertype field if the packet is untagged.
-	 */
-	if (skb->protocol == htons(ETH_P_8021Q)) {
-		skb_push(skb, DSA_HLEN);
-
-		memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
-
-		/*
-		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
-		 */
-		edsa_header = skb->data + 2 * ETH_ALEN;
-		edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
-		edsa_header[1] = ETH_P_EDSA & 0xff;
-		edsa_header[2] = 0x00;
-		edsa_header[3] = 0x00;
-		edsa_header[4] = 0x60 | dp->ds->index;
-		edsa_header[5] = dp->index << 3;
-
-		/*
-		 * Move CFI field from byte 6 to byte 5.
-		 */
-		if (edsa_header[6] & 0x10) {
-			edsa_header[5] |= 0x01;
-			edsa_header[6] &= ~0x10;
-		}
-	} else {
-		skb_push(skb, EDSA_HLEN);
-
-		memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);
-
-		/*
-		 * Construct untagged FROM_CPU DSA tag.
-		 */
-		edsa_header = skb->data + 2 * ETH_ALEN;
-		edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff;
-		edsa_header[1] = ETH_P_EDSA & 0xff;
-		edsa_header[2] = 0x00;
-		edsa_header[3] = 0x00;
-		edsa_header[4] = 0x40 | dp->ds->index;
-		edsa_header[5] = dp->index << 3;
-		edsa_header[6] = 0x00;
-		edsa_header[7] = 0x00;
-	}
-
-	return skb;
-}
-
-static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
-				struct packet_type *pt)
-{
-	u8 *edsa_header;
-	int frame_type;
-	int code;
-	int source_device;
-	int source_port;
-
-	if (unlikely(!pskb_may_pull(skb, EDSA_HLEN)))
-		return NULL;
-
-	/*
-	 * Skip the two null bytes after the ethertype.
-	 */
-	edsa_header = skb->data + 2;
-
-	/*
-	 * Check that frame type is either TO_CPU or FORWARD.
-	 */
-	frame_type = edsa_header[0] >> 6;
-
-	switch (frame_type) {
-	case FRAME_TYPE_TO_CPU:
-		code = (edsa_header[1] & 0x6) | ((edsa_header[2] >> 4) & 1);
-
-		/*
-		 * Mark the frame to never egress on any port of the same switch
-		 * unless it's a trapped IGMP/MLD packet, in which case the
-		 * bridge might want to forward it.
-		 */
-		if (code != TO_CPU_CODE_IGMP_MLD_TRAP)
-			skb->offload_fwd_mark = 1;
-
-		break;
-
-	case FRAME_TYPE_FORWARD:
-		skb->offload_fwd_mark = 1;
-		break;
-
-	default:
-		return NULL;
-	}
-
-	/*
-	 * Determine source device and port.
-	 */
-	source_device = edsa_header[0] & 0x1f;
-	source_port = (edsa_header[1] >> 3) & 0x1f;
-
-	skb->dev = dsa_master_find_slave(dev, source_device, source_port);
-	if (!skb->dev)
-		return NULL;
-
-	/*
-	 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q
-	 * tag and delete the ethertype part.  If the 'tagged' bit is
-	 * clear, delete the ethertype and the DSA tag parts.
-	 */
-	if (edsa_header[0] & 0x20) {
-		u8 new_header[4];
-
-		/*
-		 * Insert 802.1q ethertype and copy the VLAN-related
-		 * fields, but clear the bit that will hold CFI (since
-		 * DSA uses that bit location for another purpose).
-		 */
-		new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
-		new_header[1] = ETH_P_8021Q & 0xff;
-		new_header[2] = edsa_header[2] & ~0x10;
-		new_header[3] = edsa_header[3];
-
-		/*
-		 * Move CFI bit from its place in the DSA header to
-		 * its 802.1q-designated place.
-		 */
-		if (edsa_header[1] & 0x01)
-			new_header[2] |= 0x10;
-
-		skb_pull_rcsum(skb, DSA_HLEN);
-
-		/*
-		 * Update packet checksum if skb is CHECKSUM_COMPLETE.
-		 */
-		if (skb->ip_summed == CHECKSUM_COMPLETE) {
-			__wsum c = skb->csum;
-			c = csum_add(c, csum_partial(new_header + 2, 2, 0));
-			c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0));
-			skb->csum = c;
-		}
-
-		memcpy(edsa_header, new_header, DSA_HLEN);
-
-		memmove(skb->data - ETH_HLEN,
-			skb->data - ETH_HLEN - DSA_HLEN,
-			2 * ETH_ALEN);
-	} else {
-		/*
-		 * Remove DSA tag and update checksum.
-		 */
-		skb_pull_rcsum(skb, EDSA_HLEN);
-		memmove(skb->data - ETH_HLEN,
-			skb->data - ETH_HLEN - EDSA_HLEN,
-			2 * ETH_ALEN);
-	}
-
-	return skb;
-}
-
-static const struct dsa_device_ops edsa_netdev_ops = {
-	.name	= "edsa",
-	.proto	= DSA_TAG_PROTO_EDSA,
-	.xmit	= edsa_xmit,
-	.rcv	= edsa_rcv,
-	.overhead = EDSA_HLEN,
-};
-
-MODULE_LICENSE("GPL");
-MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_EDSA);
-
-module_dsa_tag_driver(edsa_netdev_ops);