mlxsw: spectrum_router: Optimize processing of VRRP MACs

Hosts using a VRRP router send their packets with a destination MAC of
the VRRP router which is of the following form [1]:

IPv4 - 00-00-5E-00-01-{VRID}
IPv6 - 00-00-5E-00-02-{VRID}

Where VRID is the ID of the virtual router. Such packets are directed to
the router block in the ASIC by an FDB entry that was added in the
previous patch.

However, in certain cases it is possible to skip this FDB lookup and
send such packets directly to the router. This is accomplished by adding
these special MAC addresses to the RIF cache. If the cache is hit, the
packet will skip the L2 lookup and ingress the router with the RIF
specified in the cache entry.

1. https://tools.ietf.org/html/rfc5798#section-7.3

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/reg.h

@@ -4353,6 +4353,20 @@ MLXSW_ITEM32(reg, ritr, if_swid, 0x08, 24, 8);
  */
 MLXSW_ITEM_BUF(reg, ritr, if_mac, 0x12, 6);
 
+/* reg_ritr_if_vrrp_id_ipv6
+ * VRRP ID for IPv6
+ * Note: Reserved for RIF types other than VLAN, FID and Sub-port.
+ * Access: RW
+ */
+MLXSW_ITEM32(reg, ritr, if_vrrp_id_ipv6, 0x1C, 8, 8);
+
+/* reg_ritr_if_vrrp_id_ipv4
+ * VRRP ID for IPv4
+ * Note: Reserved for RIF types other than VLAN, FID and Sub-port.
+ * Access: RW
+ */
+MLXSW_ITEM32(reg, ritr, if_vrrp_id_ipv4, 0x1C, 0, 8);
+
 /* VLAN Interface */
 
 /* reg_ritr_vlan_if_vid

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -6449,6 +6449,46 @@ static int mlxsw_sp_inetaddr_vlan_event(struct net_device *vlan_dev,
 	return 0;
 }
 
+static bool mlxsw_sp_rif_macvlan_is_vrrp4(const u8 *mac)
+{
+	u8 vrrp4[ETH_ALEN] = { 0x00, 0x00, 0x5e, 0x00, 0x01, 0x00 };
+	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 };
+
+	return ether_addr_equal_masked(mac, vrrp4, mask);
+}
+
+static bool mlxsw_sp_rif_macvlan_is_vrrp6(const u8 *mac)
+{
+	u8 vrrp6[ETH_ALEN] = { 0x00, 0x00, 0x5e, 0x00, 0x02, 0x00 };
+	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 };
+
+	return ether_addr_equal_masked(mac, vrrp6, mask);
+}
+
+static int mlxsw_sp_rif_vrrp_op(struct mlxsw_sp *mlxsw_sp, u16 rif_index,
+				const u8 *mac, bool adding)
+{
+	char ritr_pl[MLXSW_REG_RITR_LEN];
+	u8 vrrp_id = adding ? mac[5] : 0;
+	int err;
+
+	if (!mlxsw_sp_rif_macvlan_is_vrrp4(mac) &&
+	    !mlxsw_sp_rif_macvlan_is_vrrp6(mac))
+		return 0;
+
+	mlxsw_reg_ritr_rif_pack(ritr_pl, rif_index);
+	err = mlxsw_reg_query(mlxsw_sp->core, MLXSW_REG(ritr), ritr_pl);
+	if (err)
+		return err;
+
+	if (mlxsw_sp_rif_macvlan_is_vrrp4(mac))
+		mlxsw_reg_ritr_if_vrrp_id_ipv4_set(ritr_pl, vrrp_id);
+	else
+		mlxsw_reg_ritr_if_vrrp_id_ipv6_set(ritr_pl, vrrp_id);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ritr), ritr_pl);
+}
+
 static int mlxsw_sp_rif_macvlan_add(struct mlxsw_sp *mlxsw_sp,
 				    const struct net_device *macvlan_dev,
 				    struct netlink_ext_ack *extack)
@@ -6468,13 +6508,23 @@ static int mlxsw_sp_rif_macvlan_add(struct mlxsw_sp *mlxsw_sp,
 	if (err)
 		return err;
 
+	err = mlxsw_sp_rif_vrrp_op(mlxsw_sp, rif->rif_index,
+				   macvlan_dev->dev_addr, true);
+	if (err)
+		goto err_rif_vrrp_add;
+
 	/* Make sure the bridge driver does not have this MAC pointing at
 	 * some other port.
 	 */
 	if (rif->ops->fdb_del)
 		rif->ops->fdb_del(rif, macvlan_dev->dev_addr);
 
 	return 0;
+
+err_rif_vrrp_add:
+	mlxsw_sp_rif_fdb_op(mlxsw_sp, macvlan_dev->dev_addr,
+			    mlxsw_sp_fid_index(rif->fid), false);
+	return err;
 }
 
 void mlxsw_sp_rif_macvlan_del(struct mlxsw_sp *mlxsw_sp,
@@ -6489,6 +6539,8 @@ void mlxsw_sp_rif_macvlan_del(struct mlxsw_sp *mlxsw_sp,
 	 */
 	if (!rif)
 		return;
+	mlxsw_sp_rif_vrrp_op(mlxsw_sp, rif->rif_index, macvlan_dev->dev_addr,
+			     false);
 	mlxsw_sp_rif_fdb_op(mlxsw_sp, macvlan_dev->dev_addr,
 			    mlxsw_sp_fid_index(rif->fid), false);
 }