@@ -950,20 +950,173 @@ static void mt7530_setup_port5(struct dsa_switch *ds, phy_interface_t interface)
mutex_unlock(&priv->reg_mutex);
}
-/* On page 205, section "8.6.3 Frame filtering" of the active standard, IEEE Std
- * 802.1Q™-2022, it is stated that frames with 01:80:C2:00:00:00-0F as MAC DA
- * must only be propagated to C-VLAN and MAC Bridge components. That means
- * VLAN-aware and VLAN-unaware bridges. On the switch designs with CPU ports,
- * these frames are supposed to be processed by the CPU (software). So we make
- * the switch only forward them to the CPU port. And if received from a CPU
- * port, forward to a single port. The software is responsible of making the
- * switch conform to the latter by setting a single port as destination port on
- * the special tag.
+/* In Clause 5 of IEEE Std 802-2014, two sublayers of the data link layer (DLL)
+ * of the Open Systems Interconnection basic reference model (OSI/RM) are
+ * described; the medium access control (MAC) and logical link control (LLC)
+ * sublayers. The MAC sublayer is the one facing the physical layer.
*
- * This switch intellectual property cannot conform to this part of the standard
- * fully. Whilst the REV_UN frame tag covers the remaining :04-0D and :0F MAC
- * DAs, it also includes :22-FF which the scope of propagation is not supposed
- * to be restricted for these MAC DAs.
+ * In 8.2 of IEEE Std 802.1Q-2022, the Bridge architecture is described. A
+ * Bridge component comprises a MAC Relay Entity for interconnecting the Ports
+ * of the Bridge, at least two Ports, and higher layer entities with at least a
+ * Spanning Tree Protocol Entity included.
+ *
+ * Each Bridge Port also functions as an end station and shall provide the MAC
+ * Service to an LLC Entity. Each instance of the MAC Service is provided to a
+ * distinct LLC Entity that supports protocol identification, multiplexing, and
+ * demultiplexing, for protocol data unit (PDU) transmission and reception by
+ * one or more higher layer entities.
+ *
+ * It is described in 8.13.9 of IEEE Std 802.1Q-2022 that in a Bridge, the LLC
+ * Entity associated with each Bridge Port is modeled as being directly
+ * connected to the attached Local Area Network (LAN).
+ *
+ * On the switch with CPU port architecture, CPU port functions as Management
+ * Port, and the Management Port functionality is provided by software which
+ * functions as an end station. Software is connected to an IEEE 802 LAN that is
+ * wholly contained within the system that incorporates the Bridge. Software
+ * provides access to the LLC Entity associated with each Bridge Port by the
+ * value of the source port field on the special tag on the frame received by
+ * software.
+ *
+ * We call frames that carry control information to determine the active
+ * topology and current extent of each Virtual Local Area Network (VLAN), i.e.,
+ * spanning tree or Shortest Path Bridging (SPB) and Multiple VLAN Registration
+ * Protocol Data Units (MVRPDUs), and frames from other link constrained
+ * protocols, such as Extensible Authentication Protocol over LAN (EAPOL) and
+ * Link Layer Discovery Protocol (LLDP), link-local frames. They are not
+ * forwarded by a Bridge. Permanently configured entries in the filtering
+ * database (FDB) ensure that such frames are discarded by the Forwarding
+ * Process. In 8.6.3 of IEEE Std 802.1Q-2022, this is described in detail:
+ *
+ * Each of the reserved MAC addresses specified in Table 8-1
+ * (01-80-C2-00-00-[00,01,02,03,04,05,06,07,08,09,0A,0B,0C,0D,0E,0F]) shall be
+ * permanently configured in the FDB in C-VLAN components and ERs.
+ *
+ * Each of the reserved MAC addresses specified in Table 8-2
+ * (01-80-C2-00-00-[01,02,03,04,05,06,07,08,09,0A,0E]) shall be permanently
+ * configured in the FDB in S-VLAN components.
+ *
+ * Each of the reserved MAC addresses specified in Table 8-3
+ * (01-80-C2-00-00-[01,02,04,0E]) shall be permanently configured in the FDB in
+ * TPMR components.
+ *
+ * The FDB entries for reserved MAC addresses shall specify filtering for all
+ * Bridge Ports and all VIDs. Management shall not provide the capability to
+ * modify or remove entries for reserved MAC addresses.
+ *
+ * The addresses in Table 8-1, Table 8-2, and Table 8-3 determine the scope of
+ * propagation of PDUs within a Bridged Network, as follows:
+ *
+ * The Nearest Bridge group address (01-80-C2-00-00-0E) is an address that no
+ * conformant Two-Port MAC Relay (TPMR) component, Service VLAN (S-VLAN)
+ * component, Customer VLAN (C-VLAN) component, or MAC Bridge can forward.
+ * PDUs transmitted using this destination address, or any other addresses
+ * that appear in Table 8-1, Table 8-2, and Table 8-3
+ * (01-80-C2-00-00-[00,01,02,03,04,05,06,07,08,09,0A,0B,0C,0D,0E,0F]), can
+ * therefore travel no further than those stations that can be reached via a
+ * single individual LAN from the originating station.
+ *
+ * The Nearest non-TPMR Bridge group address (01-80-C2-00-00-03), is an
+ * address that no conformant S-VLAN component, C-VLAN component, or MAC
+ * Bridge can forward; however, this address is relayed by a TPMR component.
+ * PDUs using this destination address, or any of the other addresses that
+ * appear in both Table 8-1 and Table 8-2 but not in Table 8-3
+ * (01-80-C2-00-00-[00,03,05,06,07,08,09,0A,0B,0C,0D,0F]), will be relayed by
+ * any TPMRs but will propagate no further than the nearest S-VLAN component,
+ * C-VLAN component, or MAC Bridge.
+ *
+ * The Nearest Customer Bridge group address (01-80-C2-00-00-00) is an address
+ * that no conformant C-VLAN component, MAC Bridge can forward; however, it is
+ * relayed by TPMR components and S-VLAN components. PDUs using this
+ * destination address, or any of the other addresses that appear in Table 8-1
+ * but not in either Table 8-2 or Table 8-3 (01-80-C2-00-00-[00,0B,0C,0D,0F]),
+ * will be relayed by TPMR components and S-VLAN components but will propagate
+ * no further than the nearest C-VLAN component or MAC Bridge.
+ *
+ * Because the LLC Entity associated with each Bridge Port is provided via CPU
+ * port, we must not filter these frames but forward them to CPU port.
+ *
+ * In a Bridge, the transmission Port is majorly decided by ingress and egress
+ * rules, FDB, and spanning tree Port State functions of the Forwarding Process.
+ * For link-local frames, only CPU port should be designated as destination port
+ * in the FDB, and the other functions of the Forwarding Process must not
+ * interfere with the decision of the transmission Port. We call this process
+ * trapping frames to CPU port.
+ *
+ * Therefore, on the switch with CPU port architecture, link-local frames must
+ * be trapped to CPU port, and certain link-local frames received by a Port of a
+ * Bridge comprising a TPMR component or an S-VLAN component must be excluded
+ * from it.
+ *
+ * A Bridge of the switch with CPU port architecture cannot comprise a Two-Port
+ * MAC Relay (TPMR) component as a TPMR component supports only a subset of the
+ * functionality of a MAC Bridge. A Bridge comprising two Ports (Management Port
+ * doesn't count) of this architecture will either function as a standard MAC
+ * Bridge or a standard VLAN Bridge.
+ *
+ * Therefore, a Bridge of this architecture can only comprise S-VLAN components,
+ * C-VLAN components, or MAC Bridge components. Since there's no TPMR component,
+ * we don't need to relay PDUs using the destination addresses specified on the
+ * Nearest non-TPMR section, and the proportion of the Nearest Customer Bridge
+ * section where they must be relayed by TPMR components.
+ *
+ * One option to trap link-local frames to CPU port is to add static FDB entries
+ * with CPU port designated as destination port. However, because that
+ * Independent VLAN Learning (IVL) is being used on every VID, each entry only
+ * applies to a single VLAN Identifier (VID). For a Bridge comprising a MAC
+ * Bridge component or a C-VLAN component, there would have to be 16 times 4096
+ * entries. This switch intellectual property can only hold a maximum of 2048
+ * entries. Using this option, there also isn't a mechanism to prevent
+ * link-local frames from being discarded when the spanning tree Port State of
+ * the reception Port is discarding.
+ *
+ * The remaining option is to utilise the BPC, RGAC1, RGAC2, RGAC3, and RGAC4
+ * registers. Whilst this applies to every VID, it doesn't contain all of the
+ * reserved MAC addresses without affecting the remaining Standard Group MAC
+ * Addresses. The REV_UN frame tag utilised using the RGAC4 register covers the
+ * remaining 01-80-C2-00-00-[04,05,06,07,08,09,0A,0B,0C,0D,0F] destination
+ * addresses. It also includes the 01-80-C2-00-00-22 to 01-80-C2-00-00-FF
+ * destination addresses which may be relayed by MAC Bridges or VLAN Bridges.
+ * The latter option provides better but not complete conformance.
+ *
+ * This switch intellectual property also does not provide a mechanism to trap
+ * link-local frames with specific destination addresses to CPU port by Bridge,
+ * to conform to the filtering rules for the distinct Bridge components.
+ *
+ * Therefore, regardless of the type of the Bridge component, link-local frames
+ * with these destination addresses will be trapped to CPU port:
+ *
+ * 01-80-C2-00-00-[00,01,02,03,0E]
+ *
+ * In a Bridge comprising a MAC Bridge component or a C-VLAN component:
+ *
+ * Link-local frames with these destination addresses won't be trapped to CPU
+ * port which won't conform to IEEE Std 802.1Q-2022:
+ *
+ * 01-80-C2-00-00-[04,05,06,07,08,09,0A,0B,0C,0D,0F]
+ *
+ * In a Bridge comprising an S-VLAN component:
+ *
+ * Link-local frames with these destination addresses will be trapped to CPU
+ * port which won't conform to IEEE Std 802.1Q-2022:
+ *
+ * 01-80-C2-00-00-00
+ *
+ * Link-local frames with these destination addresses won't be trapped to CPU
+ * port which won't conform to IEEE Std 802.1Q-2022:
+ *
+ * 01-80-C2-00-00-[04,05,06,07,08,09,0A]
+ *
+ * To trap link-local frames to CPU port as conformant as this switch
+ * intellectual property can allow, link-local frames are made to be regarded as
+ * Bridge Protocol Data Units (BPDUs). This is because this switch intellectual
+ * property only lets the frames regarded as BPDUs bypass the spanning tree Port
+ * State function of the Forwarding Process.
+ *
+ * The only remaining interference is the ingress rules. When the reception Port
+ * has no PVID assigned on software, VLAN-untagged frames won't be allowed in.
+ * There doesn't seem to be a mechanism on the switch intellectual property to
+ * have link-local frames bypass this function of the Forwarding Process.
*/
static void
mt753x_trap_frames(struct mt7530_priv *priv)
@@ -971,35 +1124,43 @@ mt753x_trap_frames(struct mt7530_priv *priv)
/* Trap 802.1X PAE frames and BPDUs to the CPU port(s) and egress them
* VLAN-untagged.
*/
- mt7530_rmw(priv, MT753X_BPC, MT753X_PAE_EG_TAG_MASK |
- MT753X_PAE_PORT_FW_MASK | MT753X_BPDU_EG_TAG_MASK |
- MT753X_BPDU_PORT_FW_MASK,
- MT753X_PAE_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_PAE_PORT_FW(MT753X_BPDU_CPU_ONLY) |
- MT753X_BPDU_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_BPDU_CPU_ONLY);
+ mt7530_rmw(priv, MT753X_BPC,
+ MT753X_PAE_BPDU_FR | MT753X_PAE_EG_TAG_MASK |
+ MT753X_PAE_PORT_FW_MASK | MT753X_BPDU_EG_TAG_MASK |
+ MT753X_BPDU_PORT_FW_MASK,
+ MT753X_PAE_BPDU_FR |
+ MT753X_PAE_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_PAE_PORT_FW(MT753X_BPDU_CPU_ONLY) |
+ MT753X_BPDU_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_BPDU_CPU_ONLY);
/* Trap frames with :01 and :02 MAC DAs to the CPU port(s) and egress
* them VLAN-untagged.
*/
- mt7530_rmw(priv, MT753X_RGAC1, MT753X_R02_EG_TAG_MASK |
- MT753X_R02_PORT_FW_MASK | MT753X_R01_EG_TAG_MASK |
- MT753X_R01_PORT_FW_MASK,
- MT753X_R02_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_R02_PORT_FW(MT753X_BPDU_CPU_ONLY) |
- MT753X_R01_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_BPDU_CPU_ONLY);
+ mt7530_rmw(priv, MT753X_RGAC1,
+ MT753X_R02_BPDU_FR | MT753X_R02_EG_TAG_MASK |
+ MT753X_R02_PORT_FW_MASK | MT753X_R01_BPDU_FR |
+ MT753X_R01_EG_TAG_MASK | MT753X_R01_PORT_FW_MASK,
+ MT753X_R02_BPDU_FR |
+ MT753X_R02_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_R02_PORT_FW(MT753X_BPDU_CPU_ONLY) |
+ MT753X_R01_BPDU_FR |
+ MT753X_R01_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_BPDU_CPU_ONLY);
/* Trap frames with :03 and :0E MAC DAs to the CPU port(s) and egress
* them VLAN-untagged.
*/
- mt7530_rmw(priv, MT753X_RGAC2, MT753X_R0E_EG_TAG_MASK |
- MT753X_R0E_PORT_FW_MASK | MT753X_R03_EG_TAG_MASK |
- MT753X_R03_PORT_FW_MASK,
- MT753X_R0E_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_R0E_PORT_FW(MT753X_BPDU_CPU_ONLY) |
- MT753X_R03_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
- MT753X_BPDU_CPU_ONLY);
+ mt7530_rmw(priv, MT753X_RGAC2,
+ MT753X_R0E_BPDU_FR | MT753X_R0E_EG_TAG_MASK |
+ MT753X_R0E_PORT_FW_MASK | MT753X_R03_BPDU_FR |
+ MT753X_R03_EG_TAG_MASK | MT753X_R03_PORT_FW_MASK,
+ MT753X_R0E_BPDU_FR |
+ MT753X_R0E_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_R0E_PORT_FW(MT753X_BPDU_CPU_ONLY) |
+ MT753X_R03_BPDU_FR |
+ MT753X_R03_EG_TAG(MT7530_VLAN_EG_UNTAGGED) |
+ MT753X_BPDU_CPU_ONLY);
}
static void
@@ -65,6 +65,7 @@ enum mt753x_id {
/* Registers for BPDU and PAE frame control*/
#define MT753X_BPC 0x24
+#define MT753X_PAE_BPDU_FR BIT(25)
#define MT753X_PAE_EG_TAG_MASK GENMASK(24, 22)
#define MT753X_PAE_EG_TAG(x) FIELD_PREP(MT753X_PAE_EG_TAG_MASK, x)
#define MT753X_PAE_PORT_FW_MASK GENMASK(18, 16)
@@ -75,20 +76,24 @@ enum mt753x_id {
/* Register for :01 and :02 MAC DA frame control */
#define MT753X_RGAC1 0x28
+#define MT753X_R02_BPDU_FR BIT(25)
#define MT753X_R02_EG_TAG_MASK GENMASK(24, 22)
#define MT753X_R02_EG_TAG(x) FIELD_PREP(MT753X_R02_EG_TAG_MASK, x)
#define MT753X_R02_PORT_FW_MASK GENMASK(18, 16)
#define MT753X_R02_PORT_FW(x) FIELD_PREP(MT753X_R02_PORT_FW_MASK, x)
+#define MT753X_R01_BPDU_FR BIT(9)
#define MT753X_R01_EG_TAG_MASK GENMASK(8, 6)
#define MT753X_R01_EG_TAG(x) FIELD_PREP(MT753X_R01_EG_TAG_MASK, x)
#define MT753X_R01_PORT_FW_MASK GENMASK(2, 0)
/* Register for :03 and :0E MAC DA frame control */
#define MT753X_RGAC2 0x2c
+#define MT753X_R0E_BPDU_FR BIT(25)
#define MT753X_R0E_EG_TAG_MASK GENMASK(24, 22)
#define MT753X_R0E_EG_TAG(x) FIELD_PREP(MT753X_R0E_EG_TAG_MASK, x)
#define MT753X_R0E_PORT_FW_MASK GENMASK(18, 16)
#define MT753X_R0E_PORT_FW(x) FIELD_PREP(MT753X_R0E_PORT_FW_MASK, x)
+#define MT753X_R03_BPDU_FR BIT(9)
#define MT753X_R03_EG_TAG_MASK GENMASK(8, 6)
#define MT753X_R03_EG_TAG(x) FIELD_PREP(MT753X_R03_EG_TAG_MASK, x)
#define MT753X_R03_PORT_FW_MASK GENMASK(2, 0)