Subject: [PATCH net-next 3/3] net: dsa: mv88e6xxx: mac-auth/MAB implementation

From: "Hans J. Schultz" <[email-masked]>
Date: Mon, 5 Dec 2022 19:59:08 +0100

This implementation for the Marvell mv88e6xxx chip series, is based on
handling ATU miss violations occurring when packets ingress on a port
that is locked with learning on. This will trigger a
SWITCHDEV_FDB_ADD_TO_BRIDGE event, which will result in the bridge module
adding a locked FDB entry. This bridge FDB entry will not age out as
it has the extern_learn flag set.

Userspace daemons can listen to these events and either accept or deny
access for the host, by either replacing the locked FDB entry with a
simple entry or leave the locked entry.

If the host MAC address is already present on another port, a ATU
member violation will occur, but to no real effect. Statistics on these
violations can be shown with the command and example output of interest:

ethtool -S ethX
NIC statistics:
...
     atu_member_violation: 5
     atu_miss_violation: 23
...

Where ethX is the interface of the MAB enabled port.

An anomaly has been observed, where the ATU op to read the FID reports
FID=0 even though it is not a valid read. An -EINVAL error will be logged
in this case. This was seen on a mv88e6097.

Signed-off-by: Hans J. Schultz <[email-masked]>
---
 drivers/net/dsa/mv88e6xxx/Makefile      |  1 +
 drivers/net/dsa/mv88e6xxx/chip.c        | 18 ++++--
 drivers/net/dsa/mv88e6xxx/chip.h        | 15 +++++
 drivers/net/dsa/mv88e6xxx/global1_atu.c | 29 ++++++---
 drivers/net/dsa/mv88e6xxx/switchdev.c   | 83 +++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/switchdev.h   | 19 ++++++
 6 files changed, 152 insertions(+), 13 deletions(-)
 create mode 100644 drivers/net/dsa/mv88e6xxx/switchdev.c
 create mode 100644 drivers/net/dsa/mv88e6xxx/switchdev.h

diff --git a/drivers/net/dsa/mv88e6xxx/Makefile b/drivers/net/dsa/mv88e6xxx/Makefile
index c8eca2b6f959..be903a983780 100644
--- a/drivers/net/dsa/mv88e6xxx/Makefile
+++ b/drivers/net/dsa/mv88e6xxx/Makefile
@@ -15,3 +15,4 @@ mv88e6xxx-objs += port_hidden.o
 mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_PTP) += ptp.o
 mv88e6xxx-objs += serdes.o
 mv88e6xxx-objs += smi.o
+mv88e6xxx-objs += switchdev.o
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 66d7eae24ce0..732d7a2e2a07 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1726,11 +1726,11 @@ static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
 	return err;
 }
 
-static int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
-			      int (*cb)(struct mv88e6xxx_chip *chip,
-					const struct mv88e6xxx_vtu_entry *entry,
-					void *priv),
-			      void *priv)
+int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
+		       int (*cb)(struct mv88e6xxx_chip *chip,
+				 const struct mv88e6xxx_vtu_entry *entry,
+				 void *priv),
+		       void *priv)
 {
 	struct mv88e6xxx_vtu_entry entry = {
 		.vid = mv88e6xxx_max_vid(chip),
@@ -6524,7 +6524,7 @@ static int mv88e6xxx_port_pre_bridge_flags(struct dsa_switch *ds, int port,
 	const struct mv88e6xxx_ops *ops;
 
 	if (flags.mask & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD |
-			   BR_BCAST_FLOOD | BR_PORT_LOCKED))
+			   BR_BCAST_FLOOD | BR_PORT_LOCKED | BR_PORT_MAB))
 		return -EINVAL;
 
 	ops = chip->info->ops;
@@ -6582,6 +6582,12 @@ static int mv88e6xxx_port_bridge_flags(struct dsa_switch *ds, int port,
 			goto out;
 	}
 
+	if (flags.mask & BR_PORT_MAB) {
+		bool mab = !!(flags.val & BR_PORT_MAB);
+
+		mv88e6xxx_port_set_mab(chip, port, mab);
+	}
+
 	if (flags.mask & BR_PORT_LOCKED) {
 		bool locked = !!(flags.val & BR_PORT_LOCKED);
 
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index e693154cf803..f635a5bb47ce 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -280,6 +280,9 @@ struct mv88e6xxx_port {
 	unsigned int serdes_irq;
 	char serdes_irq_name[64];
 	struct devlink_region *region;
+
+	/* MacAuth Bypass control flag */
+	bool mab;
 };
 
 enum mv88e6xxx_region_id {
@@ -784,6 +787,12 @@ static inline bool mv88e6xxx_is_invalid_port(struct mv88e6xxx_chip *chip, int po
 	return (chip->info->invalid_port_mask & BIT(port)) != 0;
 }
 
+static inline void mv88e6xxx_port_set_mab(struct mv88e6xxx_chip *chip,
+					  int port, bool mab)
+{
+	chip->ports[port].mab = mab;
+}
+
 int mv88e6xxx_read(struct mv88e6xxx_chip *chip, int addr, int reg, u16 *val);
 int mv88e6xxx_write(struct mv88e6xxx_chip *chip, int addr, int reg, u16 val);
 int mv88e6xxx_wait_mask(struct mv88e6xxx_chip *chip, int addr, int reg,
@@ -802,6 +811,12 @@ static inline void mv88e6xxx_reg_unlock(struct mv88e6xxx_chip *chip)
 	mutex_unlock(&chip->reg_lock);
 }
 
+int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
+		       int (*cb)(struct mv88e6xxx_chip *chip,
+				 const struct mv88e6xxx_vtu_entry *entry,
+				 void *priv),
+		       void *priv);
+
 int mv88e6xxx_fid_map(struct mv88e6xxx_chip *chip, unsigned long *bitmap);
 
 #endif /* _MV88E6XXX_CHIP_H */
diff --git a/drivers/net/dsa/mv88e6xxx/global1_atu.c b/drivers/net/dsa/mv88e6xxx/global1_atu.c
index 8a874b6fc8e1..bb004df517b2 100644
--- a/drivers/net/dsa/mv88e6xxx/global1_atu.c
+++ b/drivers/net/dsa/mv88e6xxx/global1_atu.c
@@ -12,6 +12,7 @@
 
 #include "chip.h"
 #include "global1.h"
+#include "switchdev.h"
 
 /* Offset 0x01: ATU FID Register */
 
@@ -408,23 +409,25 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 
 	err = mv88e6xxx_g1_read_atu_violation(chip);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_read(chip, MV88E6XXX_G1_ATU_OP, &val);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_fid_read(chip, &fid);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_data_read(chip, &entry);
 	if (err)
-		goto out;
+		goto out_unlock;
 
 	err = mv88e6xxx_g1_atu_mac_read(chip, &entry);
 	if (err)
-		goto out;
+		goto out_unlock;
+
+	mv88e6xxx_reg_unlock(chip);
 
 	spid = entry.state;
 
@@ -446,6 +449,18 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 				    "ATU miss violation for %pM portvec %x spid %d\n",
 				    entry.mac, entry.portvec, spid);
 		chip->ports[spid].atu_miss_violation++;
+
+		if (!fid) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (chip->ports[spid].mab) {
+			err = mv88e6xxx_handle_miss_violation(chip, spid,
+							      &entry, fid);
+			if (err)
+				goto out;
+		}
 	}
 
 	if (val & MV88E6XXX_G1_ATU_OP_FULL_VIOLATION) {
@@ -454,13 +469,13 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 				    entry.mac, entry.portvec, spid);
 		chip->ports[spid].atu_full_violation++;
 	}
-	mv88e6xxx_reg_unlock(chip);
 
 	return IRQ_HANDLED;
 
-out:
+out_unlock:
 	mv88e6xxx_reg_unlock(chip);
 
+out:
 	dev_err(chip->dev, "ATU problem: error %d while handling interrupt\n",
 		err);
 	return IRQ_HANDLED;
diff --git a/drivers/net/dsa/mv88e6xxx/switchdev.c b/drivers/net/dsa/mv88e6xxx/switchdev.c
new file mode 100644
index 000000000000..4c346a884fb2
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/switchdev.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * switchdev.c
+ *
+ *	Authors:
+ *	Hans J. Schultz		<[email-masked]>
+ *
+ */
+
+#include <net/switchdev.h>
+#include "chip.h"
+#include "global1.h"
+#include "switchdev.h"
+
+struct mv88e6xxx_fid_search_ctx {
+	u16 fid_search;
+	u16 vid_found;
+};
+
+static int __mv88e6xxx_find_vid(struct mv88e6xxx_chip *chip,
+				const struct mv88e6xxx_vtu_entry *entry,
+				void *priv)
+{
+	struct mv88e6xxx_fid_search_ctx *ctx = priv;
+
+	if (ctx->fid_search == entry->fid) {
+		ctx->vid_found = entry->vid;
+		return 1;
+	}
+
+	return 0;
+}
+
+static int mv88e6xxx_find_vid(struct mv88e6xxx_chip *chip, u16 fid, u16 *vid)
+{
+	struct mv88e6xxx_fid_search_ctx ctx;
+	int err;
+
+	ctx.fid_search = fid;
+	mv88e6xxx_reg_lock(chip);
+	err = mv88e6xxx_vtu_walk(chip, __mv88e6xxx_find_vid, &ctx);
+	mv88e6xxx_reg_unlock(chip);
+	if (err < 0)
+		return err;
+	if (err == 1)
+		*vid = ctx.vid_found;
+	else
+		return -ENOENT;
+
+	return 0;
+}
+
+int mv88e6xxx_handle_miss_violation(struct mv88e6xxx_chip *chip, int port,
+				    struct mv88e6xxx_atu_entry *entry, u16 fid)
+{
+	struct switchdev_notifier_fdb_info info = {
+		.addr = entry->mac,
+		.locked = true,
+	};
+	struct net_device *brport;
+	struct dsa_port *dp;
+	u16 vid;
+	int err;
+
+	err = mv88e6xxx_find_vid(chip, fid, &vid);
+	if (err)
+		return err;
+
+	info.vid = vid;
+	dp = dsa_to_port(chip->ds, port);
+
+	rtnl_lock();
+	brport = dsa_port_to_bridge_port(dp);
+	if (!brport) {
+		rtnl_unlock();
+		return -ENODEV;
+	}
+	err = call_switchdev_notifiers(SWITCHDEV_FDB_ADD_TO_BRIDGE,
+				       brport, &info.info, NULL);
+	rtnl_unlock();
+
+	return err;
+}
diff --git a/drivers/net/dsa/mv88e6xxx/switchdev.h b/drivers/net/dsa/mv88e6xxx/switchdev.h
new file mode 100644
index 000000000000..62214f9d62b0
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/switchdev.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * switchdev.h
+ *
+ *	Authors:
+ *	Hans J. Schultz		<[email-masked]>
+ *
+ */
+
+#ifndef _MV88E6XXX_SWITCHDEV_H_
+#define _MV88E6XXX_SWITCHDEV_H_
+
+#include "chip.h"
+
+int mv88e6xxx_handle_miss_violation(struct mv88e6xxx_chip *chip, int port,
+				    struct mv88e6xxx_atu_entry *entry,
+				    u16 fid);
+
+#endif /* _MV88E6XXX_SWITCHDEV_H_ */
-- 
2.34.1