[PATCH v3 net-next 0/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[PATCH v3 net-next 0/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[Tobias Waldekranz]

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.

Tobias Waldekranz (3):
  net: dsa: tag_dsa: Allow forwarding of redirected IGMP traffic
  net: dsa: tag_dsa: Unify regular and ethertype DSA taggers
  net: dsa: tag_dsa: Use a consistent comment style

 net/dsa/Kconfig    |   5 +
 net/dsa/Makefile   |   3 +-
 net/dsa/tag_dsa.c  | 329 ++++++++++++++++++++++++++++++++++++---------
 net/dsa/tag_edsa.c | 202 ----------------------------
 4 files changed, 271 insertions(+), 268 deletions(-)
 delete mode 100644 net/dsa/tag_edsa.c

-- 
2.17.1

[PATCH v3 net-next 1/3] net: dsa: tag_dsa: Allow forwarding of redirected IGMP traffic

[Tobias Waldekranz]

When receiving an IGMP/MLD frame with a TO_CPU tag, the switch has not
performed any forwarding of it. This means that we should not set the
offload_fwd_mark on the skb, in case a software bridge wants it
forwarded.

This is a port of:

1ed9ec9b08ad ("dsa: Allow forwarding of redirected IGMP traffic")

Which corrected the issue for chips using EDSA tags, but not for those
using regular DSA tags.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/dsa/tag_dsa.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index 63d690a0fca6..af340a4945dc 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -12,6 +12,11 @@
 
 #define DSA_HLEN	4
 
+#define FRAME_TYPE_TO_CPU	0x00
+#define FRAME_TYPE_FORWARD	0x03
+
+#define TO_CPU_CODE_IGMP_MLD_TRAP	0x02
+
 static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -61,6 +66,8 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	u8 *dsa_header;
 	int source_device;
 	int source_port;
+	int frame_type;
+	int code;
 
 	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
 		return NULL;
@@ -73,8 +80,29 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	/*
 	 * Check that frame type is either TO_CPU or FORWARD.
 	 */
-	if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0)
+	frame_type = dsa_header[0] >> 6;
+
+	switch (frame_type) {
+	case FRAME_TYPE_TO_CPU:
+		code = (dsa_header[1] & 0x6) | ((dsa_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.
@@ -132,8 +160,6 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 			2 * ETH_ALEN);
 	}
 
-	skb->offload_fwd_mark = 1;
-
 	return skb;
 }
 
-- 
2.17.1

[PATCH v3 net-next 2/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[Tobias Waldekranz]

Ethertype DSA encodes exactly the same information in the DSA tag as
the non-ethertype variety. So refactor out the common parts and reuse
them for both protocols.

This is ensures tag parsing and generation is always consistent across
all mv88e6xxx chips.

While we are at it, explicitly deal with all possible CPU codes on
receive, making sure to set offload_fwd_mark as appropriate.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/dsa/Kconfig    |   5 +
 net/dsa/Makefile   |   3 +-
 net/dsa/tag_dsa.c  | 305 ++++++++++++++++++++++++++++++++++++---------
 net/dsa/tag_edsa.c | 202 ------------------------------
 4 files changed, 252 insertions(+), 263 deletions(-)
 delete mode 100644 net/dsa/tag_edsa.c

diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index d975614f7dd6..dfecd7b22fd7 100644
--- a/net/dsa/Kconfig
+++ b/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.
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index e25d5457964a..0fb2b75a7ae3 100644
--- a/net/dsa/Makefile
+++ b/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
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index af340a4945dc..04646dd71c6c 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -1,7 +1,48 @@
 // 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>
@@ -12,27 +53,92 @@
 
 #define DSA_HLEN	4
 
-#define FRAME_TYPE_TO_CPU	0x00
-#define FRAME_TYPE_FORWARD	0x03
+/**
+ * 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
+};
 
-#define TO_CPU_CODE_IGMP_MLD_TRAP	0x02
+/**
+ * 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(struct sk_buff *skb, struct net_device *dev)
+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);
+		}
+
+		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;
 
 		/*
@@ -43,15 +149,14 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
 			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;
+		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;
@@ -60,53 +165,62 @@ 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;
-	int frame_type;
-	int code;
-
-	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
-		return NULL;
 
 	/*
 	 * The ethertype field is part of the DSA header.
 	 */
 	dsa_header = skb->data - 2;
 
-	/*
-	 * Check that frame type is either TO_CPU or FORWARD.
-	 */
-	frame_type = dsa_header[0] >> 6;
+	cmd = dsa_header[0] >> 6;
+	switch (cmd) {
+	case DSA_CMD_FORWARD:
+		skb->offload_fwd_mark = 1;
+		break;
 
-	switch (frame_type) {
-	case FRAME_TYPE_TO_CPU:
+	case DSA_CMD_TO_CPU:
 		code = (dsa_header[1] & 0x6) | ((dsa_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)
+		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;
 
-	case FRAME_TYPE_FORWARD:
-		skb->offload_fwd_mark = 1;
-		break;
-
 	default:
 		return NULL;
 	}
 
-	/*
-	 * Determine source device and port.
-	 */
 	source_device = dsa_header[0] & 0x1f;
 	source_port = (dsa_header[1] >> 3) & 0x1f;
 
@@ -114,10 +228,10 @@ 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];
@@ -150,28 +264,101 @@ 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);
 	}
 
 	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");
diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
deleted file mode 100644
index abf70a29deb4..000000000000
--- a/net/dsa/tag_edsa.c
+++ /dev/null
@@ -1,202 +0,0 @@
-// 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);
-- 
2.17.1

[PATCH v3 net-next 3/3] net: dsa: tag_dsa: Use a consistent comment style

[Tobias Waldekranz]

Use a consistent style of one-line/multi-line comments throughout the
file.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 net/dsa/tag_dsa.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index 04646dd71c6c..112c7c6dd568 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -129,21 +129,17 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 	u8 *dsa_header;
 
 	if (skb->protocol == htons(ETH_P_8021Q)) {
-		/*
-		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
-		 */
 		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;
@@ -152,9 +148,7 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 		skb_push(skb, DSA_HLEN + extra);
 		memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);
 
-		/*
-		 * Construct untagged FROM_CPU DSA tag.
-		 */
+		/* 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;
@@ -173,9 +167,7 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
 	enum dsa_cmd cmd;
 	u8 *dsa_header;
 
-	/*
-	 * The ethertype field is part of the DSA header.
-	 */
+	/* The ethertype field is part of the DSA header. */
 	dsa_header = skb->data - 2;
 
 	cmd = dsa_header[0] >> 6;
@@ -236,8 +228,7 @@ static struct sk_buff *dsa_rcv_ll(struct sk_buff *skb, struct net_device *dev,
 	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).
 		 */
@@ -246,16 +237,13 @@ static struct sk_buff *dsa_rcv_ll(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));
-- 
2.17.1

Re: [PATCH v3 net-next 1/3] net: dsa: tag_dsa: Allow forwarding of redirected IGMP traffic

[Andrew Lunn]

On Sun, Nov 15, 2020 at 12:45:56AM +0100, Tobias Waldekranz wrote:
> When receiving an IGMP/MLD frame with a TO_CPU tag, the switch has not
> performed any forwarding of it. This means that we should not set the
> offload_fwd_mark on the skb, in case a software bridge wants it
> forwarded.
> 
> This is a port of:
> 
> 1ed9ec9b08ad ("dsa: Allow forwarding of redirected IGMP traffic")
> 
> Which corrected the issue for chips using EDSA tags, but not for those
> using regular DSA tags.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH v3 net-next 3/3] net: dsa: tag_dsa: Use a consistent comment style

[Andrew Lunn]

On Sun, Nov 15, 2020 at 12:45:58AM +0100, Tobias Waldekranz wrote:
> Use a consistent style of one-line/multi-line comments throughout the
> file.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH v3 net-next 2/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[Andrew Lunn]

On Sun, Nov 15, 2020 at 12:45:57AM +0100, Tobias Waldekranz wrote:
> Ethertype DSA encodes exactly the same information in the DSA tag as
> the non-ethertype variety. So refactor out the common parts and reuse
> them for both protocols.
> 
> This is ensures tag parsing and generation is always consistent across
> all mv88e6xxx chips.
> 
> While we are at it, explicitly deal with all possible CPU codes on
> receive, making sure to set offload_fwd_mark as appropriate.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH v3 net-next 1/3] net: dsa: tag_dsa: Allow forwarding of redirected IGMP traffic

[Florian Fainelli]

On 11/14/2020 3:45 PM, Tobias Waldekranz wrote:
> When receiving an IGMP/MLD frame with a TO_CPU tag, the switch has not
> performed any forwarding of it. This means that we should not set the
> offload_fwd_mark on the skb, in case a software bridge wants it
> forwarded.
> 
> This is a port of:
> 
> 1ed9ec9b08ad ("dsa: Allow forwarding of redirected IGMP traffic")
> 
> Which corrected the issue for chips using EDSA tags, but not for those
> using regular DSA tags.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH v3 net-next 2/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[Florian Fainelli]

On 11/14/2020 3:45 PM, Tobias Waldekranz wrote:
> Ethertype DSA encodes exactly the same information in the DSA tag as
> the non-ethertype variety. So refactor out the common parts and reuse
> them for both protocols.
> 
> This is ensures tag parsing and generation is always consistent across
> all mv88e6xxx chips.
> 
> While we are at it, explicitly deal with all possible CPU codes on
> receive, making sure to set offload_fwd_mark as appropriate.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH v3 net-next 3/3] net: dsa: tag_dsa: Use a consistent comment style

[Florian Fainelli]

On 11/14/2020 3:45 PM, Tobias Waldekranz wrote:
> Use a consistent style of one-line/multi-line comments throughout the
> file.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH v3 net-next 0/3] net: dsa: tag_dsa: Unify regular and ethertype DSA taggers

[Jakub Kicinski]

On Sun, 15 Nov 2020 00:45:55 +0100 Tobias Waldekranz wrote:
> 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.

Applied, thanks everyone!