mlxsw: spectrum_acl: Offload FLOW_ACTION_SAMPLE

Implement support for action sample when used with a flower classifier
by implementing the required sampler_add() / sampler_del() callbacks and
registering an Rx listener for the sampled packets.

The sampler_add() callback returns an error for Spectrum-1 as the
functionality is not supported. In Spectrum-{2,3} the callback creates a
mirroring agent towards the CPU. The agent's identifier is used by the
policy engine code to mirror towards the CPU with probability.

The Rx listener for the sampled packet is registered with the 'policy
engine' mirroring reason and passes trapped packets to the psample
module after looking up their parameters (e.g., sampling group).

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
index 3dbf5e53e9ff..26d01adbedad 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_trap.c
@@ -51,6 +51,8 @@ enum {
 enum {
 	/* Packet was mirrored from ingress. */
 	MLXSW_SP_MIRROR_REASON_INGRESS = 1,
+	/* Packet was mirrored from policy engine. */
+	MLXSW_SP_MIRROR_REASON_POLICY_ENGINE = 2,
 	/* Packet was early dropped. */
 	MLXSW_SP_MIRROR_REASON_INGRESS_WRED = 9,
 	/* Packet was mirrored from egress. */
@@ -341,6 +343,42 @@ out:
 	consume_skb(skb);
 }
 
+static void mlxsw_sp_rx_sample_acl_listener(struct sk_buff *skb, u8 local_port,
+					    void *trap_ctx)
+{
+	struct mlxsw_sp *mlxsw_sp = devlink_trap_ctx_priv(trap_ctx);
+	struct mlxsw_sp_sample_trigger trigger = {
+		.type = MLXSW_SP_SAMPLE_TRIGGER_TYPE_POLICY_ENGINE,
+	};
+	struct mlxsw_sp_sample_params *params;
+	struct mlxsw_sp_port *mlxsw_sp_port;
+	struct psample_metadata md = {};
+	int err;
+
+	err = __mlxsw_sp_rx_no_mark_listener(skb, local_port, trap_ctx);
+	if (err)
+		return;
+
+	mlxsw_sp_port = mlxsw_sp->ports[local_port];
+	if (!mlxsw_sp_port)
+		goto out;
+
+	params = mlxsw_sp_sample_trigger_params_lookup(mlxsw_sp, &trigger);
+	if (!params)
+		goto out;
+
+	/* The psample module expects skb->data to point to the start of the
+	 * Ethernet header.
+	 */
+	skb_push(skb, ETH_HLEN);
+	mlxsw_sp_psample_md_init(mlxsw_sp, &md, skb,
+				 mlxsw_sp_port->dev->ifindex, params->truncate,
+				 params->trunc_size);
+	psample_sample_packet(params->psample_group, skb, params->rate, &md);
+out:
+	consume_skb(skb);
+}
+
 #define MLXSW_SP_TRAP_DROP(_id, _group_id)				      \
 	DEVLINK_TRAP_GENERIC(DROP, DROP, _id,				      \
 			     DEVLINK_TRAP_GROUP_GENERIC_ID_##_group_id,	      \
@@ -1898,6 +1936,9 @@ mlxsw_sp2_trap_items_arr[] = {
 			MLXSW_RXL_MIRROR(mlxsw_sp_rx_sample_tx_listener, 1,
 					 SP_PKT_SAMPLE,
 					 MLXSW_SP_MIRROR_REASON_EGRESS),
+			MLXSW_RXL_MIRROR(mlxsw_sp_rx_sample_acl_listener, 1,
+					 SP_PKT_SAMPLE,
+					 MLXSW_SP_MIRROR_REASON_POLICY_ENGINE),
 		},
 	},
 };