net: dsa: mv88e6xxx: mac-auth/MAB implementation

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, and the packet will
be dropped in hardware. 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.

Furthermore, as added vlan interfaces where the vid is not added to the
VTU will cause ATU miss violations reporting the FID as
MV88E6XXX_FID_STANDALONE, we need to check and skip the miss violations
handling in this case.
Signed-off-by: Hans J. Schultz <netdev@kapio-technology.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/dsa/mv88e6xxx/Makefile

@@ -15,6 +15,7 @@ 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
 mv88e6xxx-objs += trace.o
 
 # for tracing framework to find trace.h

drivers/net/dsa/mv88e6xxx/chip.c

@@ -1728,7 +1728,7 @@ static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
 	return err;
 }
 
-static int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
+int mv88e6xxx_vtu_walk(struct mv88e6xxx_chip *chip,
 		       int (*cb)(struct mv88e6xxx_chip *chip,
 				 const struct mv88e6xxx_vtu_entry *entry,
 				 void *priv),
@@ -6526,7 +6526,7 @@ 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;
@@ -6584,6 +6584,12 @@ 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);
 

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 */

drivers/net/dsa/mv88e6xxx/global1_atu.c

@@ -12,6 +12,7 @@
 
 #include "chip.h"
 #include "global1.h"
+#include "switchdev.h"
 #include "trace.h"
 
 /* Offset 0x01: ATU FID Register */
@@ -443,6 +444,13 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 						   entry.portvec, entry.mac,
 						   fid);
 		chip->ports[spid].atu_miss_violation++;
+
+		if (fid != MV88E6XXX_FID_STANDALONE && 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) {
@@ -456,6 +464,8 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 
 out_unlock:
 	mv88e6xxx_reg_unlock(chip);
+
+out:
 	dev_err(chip->dev, "ATU problem: error %d while handling interrupt\n",
 		err);
 	return IRQ_HANDLED;

drivers/net/dsa/mv88e6xxx/switchdev.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * switchdev.c
+ *
+ *	Authors:
+ *	Hans J. Schultz		<netdev@kapio-technology.com>
+ *
+ */
+
+#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;
+}

drivers/net/dsa/mv88e6xxx/switchdev.h

+/* SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * switchdev.h
+ *
+ *	Authors:
+ *	Hans J. Schultz		<netdev@kapio-technology.com>
+ *
+ */
+
+#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_ */