diff mbox series

[v2,net-next,1/5] net: dsa: mv88e6xxx: Improve isolation of standalone ports

Message ID 20220203101657.990241-2-tobias@waldekranz.com (mailing list archive)
State Accepted
Commit 7af4a361a62f59b44ec301f21090823365dd0244
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: mv88e6xxx: Improve standalone port isolation | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 18 this patch: 18
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 24 this patch: 24
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 23 this patch: 23
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Tobias Waldekranz Feb. 3, 2022, 10:16 a.m. UTC
Clear MapDA on standalone ports to bypass any ATU lookup that might
point the packet in the wrong direction. This means that all packets
are flooded using the PVT config. So make sure that standalone ports
are only allowed to communicate with the local upstream port.

Here is a scenario in which this is needed:

   CPU
    |     .----.
.---0---. | .--0--.
|  sw0  | | | sw1 |
'-1-2-3-' | '-1-2-'
      '---'

- sw0p1 and sw1p1 are bridged
- sw0p2 and sw1p2 are in standalone mode
- Learning must be enabled on sw0p3 in order for hardware forwarding
  to work properly between bridged ports

1. A packet with SA :aa comes in on sw1p2
   1a. Egresses sw1p0
   1b. Ingresses sw0p3, ATU adds an entry for :aa towards port 3
   1c. Egresses sw0p0

2. A packet with DA :aa comes in on sw0p2
   2a. If an ATU lookup is done at this point, the packet will be
       incorrectly forwarded towards sw0p3. With this change in place,
       the ATU is bypassed and the packet is forwarded in accordance
       with the PVT, which only contains the CPU port.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 32 +++++++++++++++++++++++++-------
 drivers/net/dsa/mv88e6xxx/port.c |  7 +++++--
 drivers/net/dsa/mv88e6xxx/port.h |  2 +-
 include/net/dsa.h                | 12 ++++++++++++
 4 files changed, 43 insertions(+), 10 deletions(-)

Comments

Vladimir Oltean Feb. 3, 2022, 12:43 p.m. UTC | #1
On Thu, Feb 03, 2022 at 11:16:53AM +0100, Tobias Waldekranz wrote:
> Clear MapDA on standalone ports to bypass any ATU lookup that might
> point the packet in the wrong direction. This means that all packets
> are flooded using the PVT config. So make sure that standalone ports
> are only allowed to communicate with the local upstream port.
> 
> Here is a scenario in which this is needed:
> 
>    CPU
>     |     .----.
> .---0---. | .--0--.
> |  sw0  | | | sw1 |
> '-1-2-3-' | '-1-2-'
>       '---'
> 
> - sw0p1 and sw1p1 are bridged
> - sw0p2 and sw1p2 are in standalone mode
> - Learning must be enabled on sw0p3 in order for hardware forwarding
>   to work properly between bridged ports
> 
> 1. A packet with SA :aa comes in on sw1p2
>    1a. Egresses sw1p0
>    1b. Ingresses sw0p3, ATU adds an entry for :aa towards port 3
>    1c. Egresses sw0p0
> 
> 2. A packet with DA :aa comes in on sw0p2
>    2a. If an ATU lookup is done at this point, the packet will be
>        incorrectly forwarded towards sw0p3. With this change in place,
>        the ATU is bypassed and the packet is forwarded in accordance
>        with the PVT, which only contains the CPU port.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
diff mbox series

Patch

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 1023e4549359..7f02ec502e71 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1290,8 +1290,15 @@  static u16 mv88e6xxx_port_vlan(struct mv88e6xxx_chip *chip, int dev, int port)
 
 	pvlan = 0;
 
-	/* Frames from user ports can egress any local DSA links and CPU ports,
-	 * as well as any local member of their bridge group.
+	/* Frames from standalone user ports can only egress on the
+	 * upstream port.
+	 */
+	if (!dsa_port_bridge_dev_get(dp))
+		return BIT(dsa_switch_upstream_port(ds));
+
+	/* Frames from bridged user ports can egress any local DSA
+	 * links and CPU ports, as well as any local member of their
+	 * bridge group.
 	 */
 	dsa_switch_for_each_port(other_dp, ds)
 		if (other_dp->type == DSA_PORT_TYPE_CPU ||
@@ -2487,6 +2494,10 @@  static int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
 	if (err)
 		goto unlock;
 
+	err = mv88e6xxx_port_set_map_da(chip, port, true);
+	if (err)
+		return err;
+
 	err = mv88e6xxx_port_commit_pvid(chip, port);
 	if (err)
 		goto unlock;
@@ -2521,6 +2532,12 @@  static void mv88e6xxx_port_bridge_leave(struct dsa_switch *ds, int port,
 	    mv88e6xxx_port_vlan_map(chip, port))
 		dev_err(ds->dev, "failed to remap in-chip Port VLAN\n");
 
+	err = mv88e6xxx_port_set_map_da(chip, port, false);
+	if (err)
+		dev_err(ds->dev,
+			"port %d failed to restore map-DA: %pe\n",
+			port, ERR_PTR(err));
+
 	err = mv88e6xxx_port_commit_pvid(chip, port);
 	if (err)
 		dev_err(ds->dev,
@@ -2918,12 +2935,13 @@  static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
 		return err;
 
 	/* Port Control 2: don't force a good FCS, set the MTU size to
-	 * 10222 bytes, disable 802.1q tags checking, don't discard tagged or
-	 * untagged frames on this port, do a destination address lookup on all
-	 * received packets as usual, disable ARP mirroring and don't send a
-	 * copy of all transmitted/received frames on this port to the CPU.
+	 * 10222 bytes, disable 802.1q tags checking, don't discard
+	 * tagged or untagged frames on this port, skip destination
+	 * address lookup on user ports, disable ARP mirroring and don't
+	 * send a copy of all transmitted/received frames on this port
+	 * to the CPU.
 	 */
-	err = mv88e6xxx_port_set_map_da(chip, port);
+	err = mv88e6xxx_port_set_map_da(chip, port, !dsa_is_user_port(ds, port));
 	if (err)
 		return err;
 
diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index ab41619a809b..ceb450113f88 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -1278,7 +1278,7 @@  int mv88e6xxx_port_drop_untagged(struct mv88e6xxx_chip *chip, int port,
 	return mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_CTL2, new);
 }
 
-int mv88e6xxx_port_set_map_da(struct mv88e6xxx_chip *chip, int port)
+int mv88e6xxx_port_set_map_da(struct mv88e6xxx_chip *chip, int port, bool map)
 {
 	u16 reg;
 	int err;
@@ -1287,7 +1287,10 @@  int mv88e6xxx_port_set_map_da(struct mv88e6xxx_chip *chip, int port)
 	if (err)
 		return err;
 
-	reg |= MV88E6XXX_PORT_CTL2_MAP_DA;
+	if (map)
+		reg |= MV88E6XXX_PORT_CTL2_MAP_DA;
+	else
+		reg &= ~MV88E6XXX_PORT_CTL2_MAP_DA;
 
 	return mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_CTL2, reg);
 }
diff --git a/drivers/net/dsa/mv88e6xxx/port.h b/drivers/net/dsa/mv88e6xxx/port.h
index 03382b66f800..5c347cc58baf 100644
--- a/drivers/net/dsa/mv88e6xxx/port.h
+++ b/drivers/net/dsa/mv88e6xxx/port.h
@@ -425,7 +425,7 @@  int mv88e6185_port_get_cmode(struct mv88e6xxx_chip *chip, int port, u8 *cmode);
 int mv88e6352_port_get_cmode(struct mv88e6xxx_chip *chip, int port, u8 *cmode);
 int mv88e6xxx_port_drop_untagged(struct mv88e6xxx_chip *chip, int port,
 				 bool drop_untagged);
-int mv88e6xxx_port_set_map_da(struct mv88e6xxx_chip *chip, int port);
+int mv88e6xxx_port_set_map_da(struct mv88e6xxx_chip *chip, int port, bool map);
 int mv88e6095_port_set_upstream_port(struct mv88e6xxx_chip *chip, int port,
 				     int upstream_port);
 int mv88e6xxx_port_set_mirror(struct mv88e6xxx_chip *chip, int port,
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 43c4153ef53a..6e5ef62a7dce 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -591,6 +591,18 @@  static inline bool dsa_is_upstream_port(struct dsa_switch *ds, int port)
 	return port == dsa_upstream_port(ds, port);
 }
 
+/* Return the local port used to reach the CPU port */
+static inline unsigned int dsa_switch_upstream_port(struct dsa_switch *ds)
+{
+	struct dsa_port *dp;
+
+	dsa_switch_for_each_available_port(dp, ds) {
+		return dsa_upstream_port(ds, dp->index);
+	}
+
+	return ds->num_ports;
+}
+
 /* Return true if @upstream_ds is an upstream switch of @downstream_ds, meaning
  * that the routing port from @downstream_ds to @upstream_ds is also the port
  * which @downstream_ds uses to reach its dedicated CPU.