Given that standalone ports are now configured to bypass the ATU and
forward all frames towards the upstream port, extend the ATU bypass to
multichip systems.
Load VID 0 (standalone) into the VTU with the policy bit set. Since
VID 4095 (bridged) is already loaded, we now know that all VIDs in use
are always available in all VTUs. Therefore, we can safely enable
802.1Q on DSA ports.
Setting the DSA ports' VTU policy to TRAP means that all incoming
frames on VID 0 will be classified as MGMT - as a result, the ATU is
bypassed on all subsequent switches.
With this isolation in place, we are able to support configurations
that are simultaneously very quirky and very useful. Quirky because it
involves looping cables between local switchports like in this
example:
CPU
| .------.
.---0---. | .----0----.
| sw0 | | | sw1 |
'-1-2-3-' | '-1-2-3-4-'
$ @ '---' $ @ % %
We have three physically looped pairs ($, @, and %).
This is very useful because it allows us to run the kernel's
kselftests for the bridge on mv88e6xxx hardware.
Signed-off-by: Tobias Waldekranz <[email protected]>
---
drivers/net/dsa/mv88e6xxx/chip.c | 63 ++++++++++++++++++++++----------
1 file changed, 44 insertions(+), 19 deletions(-)
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 8896709b9103..d0d766354669 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1630,21 +1630,11 @@ static int mv88e6xxx_fid_map_vlan(struct mv88e6xxx_chip *chip,
int mv88e6xxx_fid_map(struct mv88e6xxx_chip *chip, unsigned long *fid_bitmap)
{
- int i, err;
- u16 fid;
-
bitmap_zero(fid_bitmap, MV88E6XXX_N_FID);
- /* Set every FID bit used by the (un)bridged ports */
- for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
- err = mv88e6xxx_port_get_fid(chip, i, &fid);
- if (err)
- return err;
-
- set_bit(fid, fid_bitmap);
- }
-
- /* Set every FID bit used by the VLAN entries */
+ /* Every FID has an associated VID, so walking the VTU
+ * will discover the full set of FIDs in use.
+ */
return mv88e6xxx_vtu_walk(chip, mv88e6xxx_fid_map_vlan, fid_bitmap);
}
@@ -1657,10 +1647,7 @@ static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip, u16 *fid)
if (err)
return err;
- /* The reset value 0x000 is used to indicate that multiple address
- * databases are not needed. Return the next positive available.
- */
- *fid = find_next_zero_bit(fid_bitmap, MV88E6XXX_N_FID, 1);
+ *fid = find_first_zero_bit(fid_bitmap, MV88E6XXX_N_FID);
if (unlikely(*fid >= mv88e6xxx_num_databases(chip)))
return -ENOSPC;
@@ -2152,6 +2139,9 @@ static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
if (!vlan.valid) {
memset(&vlan, 0, sizeof(vlan));
+ if (vid == MV88E6XXX_VID_STANDALONE)
+ vlan.policy = true;
+
err = mv88e6xxx_atu_new(chip, &vlan.fid);
if (err)
return err;
@@ -2949,8 +2939,43 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
if (err)
return err;
+ /* On chips that support it, set all DSA ports' VLAN policy to
+ * TRAP. In combination with loading MV88E6XXX_VID_STANDALONE
+ * as a policy entry in the VTU, this provides a better
+ * isolation barrier between standalone ports, as the ATU is
+ * bypassed on any intermediate switches between the incoming
+ * port and the CPU.
+ */
+ if (!dsa_is_user_port(ds, port) && chip->info->ops->port_set_policy) {
+ err = chip->info->ops->port_set_policy(chip, port,
+ MV88E6XXX_POLICY_MAPPING_VTU,
+ MV88E6XXX_POLICY_ACTION_TRAP);
+ if (err)
+ return err;
+ }
+
+ /* User ports start out in standalone mode and 802.1Q is
+ * therefore disabled. On DSA ports, all valid VIDs are always
+ * loaded in the VTU - therefore, enable 802.1Q in order to take
+ * advantage of VLAN policy on chips that supports it.
+ */
err = mv88e6xxx_port_set_8021q_mode(chip, port,
- MV88E6XXX_PORT_CTL2_8021Q_MODE_DISABLED);
+ dsa_is_user_port(ds, port) ?
+ MV88E6XXX_PORT_CTL2_8021Q_MODE_DISABLED :
+ MV88E6XXX_PORT_CTL2_8021Q_MODE_SECURE);
+ if (err)
+ return err;
+
+ /* Bind MV88E6XXX_VID_STANDALONE to MV88E6XXX_FID_STANDALONE by
+ * virtue of the fact that mv88e6xxx_atu_new() will pick it as
+ * the first free FID. This will be used as the private PVID for
+ * unbridged ports. Shared (DSA and CPU) ports must also be
+ * members of this VID, in order to trap all frames assigned to
+ * it to the CPU.
+ */
+ err = mv88e6xxx_port_vlan_join(chip, port, MV88E6XXX_VID_STANDALONE,
+ MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNMODIFIED,
+ false);
if (err)
return err;
@@ -2963,7 +2988,7 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
* relying on their port default FID.
*/
err = mv88e6xxx_port_vlan_join(chip, port, MV88E6XXX_VID_BRIDGED,
- MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNTAGGED,
+ MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNMODIFIED,
false);
if (err)
return err;
--
2.25.1
On Mon, Jan 31, 2022 at 04:46:54PM +0100, Tobias Waldekranz wrote:
> Given that standalone ports are now configured to bypass the ATU and
> forward all frames towards the upstream port, extend the ATU bypass to
> multichip systems.
>
> Load VID 0 (standalone) into the VTU with the policy bit set. Since
> VID 4095 (bridged) is already loaded, we now know that all VIDs in use
> are always available in all VTUs. Therefore, we can safely enable
> 802.1Q on DSA ports.
>
> Setting the DSA ports' VTU policy to TRAP means that all incoming
> frames on VID 0 will be classified as MGMT - as a result, the ATU is
> bypassed on all subsequent switches.
>
> With this isolation in place, we are able to support configurations
> that are simultaneously very quirky and very useful. Quirky because it
> involves looping cables between local switchports like in this
> example:
>
> CPU
> | .------.
> .---0---. | .----0----.
> | sw0 | | | sw1 |
> '-1-2-3-' | '-1-2-3-4-'
> $ @ '---' $ @ % %
>
> We have three physically looped pairs ($, @, and %).
>
> This is very useful because it allows us to run the kernel's
> kselftests for the bridge on mv88e6xxx hardware.
>
> Signed-off-by: Tobias Waldekranz <[email protected]>
> ---
> drivers/net/dsa/mv88e6xxx/chip.c | 63 ++++++++++++++++++++++----------
> 1 file changed, 44 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index 8896709b9103..d0d766354669 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -1630,21 +1630,11 @@ static int mv88e6xxx_fid_map_vlan(struct mv88e6xxx_chip *chip,
>
> int mv88e6xxx_fid_map(struct mv88e6xxx_chip *chip, unsigned long *fid_bitmap)
> {
> - int i, err;
> - u16 fid;
> -
> bitmap_zero(fid_bitmap, MV88E6XXX_N_FID);
>
> - /* Set every FID bit used by the (un)bridged ports */
> - for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
> - err = mv88e6xxx_port_get_fid(chip, i, &fid);
> - if (err)
> - return err;
> -
> - set_bit(fid, fid_bitmap);
> - }
> -
> - /* Set every FID bit used by the VLAN entries */
> + /* Every FID has an associated VID, so walking the VTU
> + * will discover the full set of FIDs in use.
> + */
So practically, regardless of whether the switch supports VTU policy or
not, we still load VID 0 in the VTU, and this simplifies the driver a
bit. Could we also simplify mv88e6xxx_port_db_dump() by deleting the
mv88e6xxx_port_get_fid() from there (and then delete this function
altogether)?
I think the mv88e6xxx_port_set_fid() call is now useless too?
> return mv88e6xxx_vtu_walk(chip, mv88e6xxx_fid_map_vlan, fid_bitmap);
> }
>
> @@ -1657,10 +1647,7 @@ static int mv88e6xxx_atu_new(struct mv88e6xxx_chip *chip, u16 *fid)
> if (err)
> return err;
>
> - /* The reset value 0x000 is used to indicate that multiple address
> - * databases are not needed. Return the next positive available.
> - */
> - *fid = find_next_zero_bit(fid_bitmap, MV88E6XXX_N_FID, 1);
> + *fid = find_first_zero_bit(fid_bitmap, MV88E6XXX_N_FID);
> if (unlikely(*fid >= mv88e6xxx_num_databases(chip)))
> return -ENOSPC;
>
> @@ -2152,6 +2139,9 @@ static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
> if (!vlan.valid) {
> memset(&vlan, 0, sizeof(vlan));
>
> + if (vid == MV88E6XXX_VID_STANDALONE)
> + vlan.policy = true;
> +
> err = mv88e6xxx_atu_new(chip, &vlan.fid);
> if (err)
> return err;
> @@ -2949,8 +2939,43 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
> if (err)
> return err;
>
> + /* On chips that support it, set all DSA ports' VLAN policy to
> + * TRAP. In combination with loading MV88E6XXX_VID_STANDALONE
> + * as a policy entry in the VTU, this provides a better
> + * isolation barrier between standalone ports, as the ATU is
> + * bypassed on any intermediate switches between the incoming
> + * port and the CPU.
> + */
> + if (!dsa_is_user_port(ds, port) && chip->info->ops->port_set_policy) {
Will this not also affect FWD frames sent on behalf of VLAN-unaware
bridges as they are received on CPU ports and upstream-facing DSA ports?
Somehow I think you intend to make this match only on downstream-facing
DSA ports.
> + err = chip->info->ops->port_set_policy(chip, port,
> + MV88E6XXX_POLICY_MAPPING_VTU,
> + MV88E6XXX_POLICY_ACTION_TRAP);
> + if (err)
> + return err;
> + }
> +
> + /* User ports start out in standalone mode and 802.1Q is
> + * therefore disabled. On DSA ports, all valid VIDs are always
> + * loaded in the VTU - therefore, enable 802.1Q in order to take
> + * advantage of VLAN policy on chips that supports it.
> + */
Is this really needed? I thought cascade ports parse the VID from the
DSA header regardless of 802.1Q mode.
> err = mv88e6xxx_port_set_8021q_mode(chip, port,
> - MV88E6XXX_PORT_CTL2_8021Q_MODE_DISABLED);
> + dsa_is_user_port(ds, port) ?
> + MV88E6XXX_PORT_CTL2_8021Q_MODE_DISABLED :
> + MV88E6XXX_PORT_CTL2_8021Q_MODE_SECURE);
> + if (err)
> + return err;
> +
> + /* Bind MV88E6XXX_VID_STANDALONE to MV88E6XXX_FID_STANDALONE by
> + * virtue of the fact that mv88e6xxx_atu_new() will pick it as
> + * the first free FID. This will be used as the private PVID for
> + * unbridged ports. Shared (DSA and CPU) ports must also be
> + * members of this VID, in order to trap all frames assigned to
> + * it to the CPU.
> + */
> + err = mv88e6xxx_port_vlan_join(chip, port, MV88E6XXX_VID_STANDALONE,
> + MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNMODIFIED,
> + false);
> if (err)
> return err;
>
> @@ -2963,7 +2988,7 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
> * relying on their port default FID.
> */
> err = mv88e6xxx_port_vlan_join(chip, port, MV88E6XXX_VID_BRIDGED,
> - MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNTAGGED,
> + MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNMODIFIED,
I think the idea with UNTAGGED here was that packets sent by tag_dsa.c
with TX forwarding offload on behalf of a VLAN-unaware bridge have VID
4095. By setting the port as untagged, that VID is stripped on egress.
If you make it UNMODIFIED, the outside world will see it. Or am I wrong?
> false);
> if (err)
> return err;
> --
> 2.25.1
>