net/mlx5e: Implement MACsec Rx data path using MACsec skb_metadata_dst

MACsec driver need to distinguish to which offload device the MACsec
is target to, in order to handle them correctly.
This can be done by attaching a metadata_dst to a SKB with a SCI,
when there is a match on MACsec rule.
To achieve that, there is a map between fs_id to SCI, so for each RX SC,
there is a unique fs_id allocated when creating RX SC.
fs_id passed to device driver as metadata for packets that passed Rx
MACsec offload to aid the driver to retrieve the matching SCI.

Signed-off-by: Lior Nahmanson <liorna@nvidia.com>
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Lior Nahmanson

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_rxtx.h

@@ -39,9 +39,9 @@
 #include "en.h"
 #include "en/txrx.h"
 
-/* Bit31: IPsec marker, Bit30-24: IPsec syndrome, Bit23-0: IPsec obj id */
+/* Bit31: IPsec marker, Bit30: reserved, Bit29-24: IPsec syndrome, Bit23-0: IPsec obj id */
 #define MLX5_IPSEC_METADATA_MARKER(metadata)  (((metadata) >> 31) & 0x1)
-#define MLX5_IPSEC_METADATA_SYNDROM(metadata) (((metadata) >> 24) & GENMASK(6, 0))
+#define MLX5_IPSEC_METADATA_SYNDROM(metadata) (((metadata) >> 24) & GENMASK(5, 0))
 #define MLX5_IPSEC_METADATA_HANDLE(metadata)  ((metadata) & GENMASK(23, 0))
 
 struct mlx5e_accel_tx_ipsec_state {

drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c

@@ -39,6 +39,7 @@ struct mlx5e_macsec_rx_sc {
 	struct mlx5e_macsec_sa *rx_sa[MACSEC_NUM_AN];
 	struct list_head rx_sc_list_element;
 	struct mlx5e_macsec_rx_sc_xarray_element *sc_xarray_element;
+	struct metadata_dst *md_dst;
 	struct rcu_head rcu_head;
 };
 
@@ -455,16 +456,24 @@ static int mlx5e_macsec_add_rxsc(struct macsec_context *ctx)
 	if (err)
 		goto destroy_sc_xarray_elemenet;
 
+	rx_sc->md_dst = metadata_dst_alloc(0, METADATA_MACSEC, GFP_KERNEL);
+	if (!rx_sc->md_dst) {
+		err = -ENOMEM;
+		goto erase_xa_alloc;
+	}
+
 	rx_sc->sci = ctx_rx_sc->sci;
 	rx_sc->active = ctx_rx_sc->active;
 	list_add_rcu(&rx_sc->rx_sc_list_element, &macsec->macsec_rx_sc_list_head);
 
 	rx_sc->sc_xarray_element = sc_xarray_element;
-
+	rx_sc->md_dst->u.macsec_info.sci = rx_sc->sci;
 	mutex_unlock(&macsec->lock);
 
 	return 0;
 
+erase_xa_alloc:
+	xa_erase(&macsec->sc_xarray, sc_xarray_element->fs_id);
 destroy_sc_xarray_elemenet:
 	kfree(sc_xarray_element);
 destroy_rx_sc:
@@ -558,8 +567,15 @@ static int mlx5e_macsec_del_rxsc(struct macsec_context *ctx)
 		rx_sc->rx_sa[i] = NULL;
 	}
 
+/*
+ * At this point the relevant MACsec offload Rx rule already removed at
+ * mlx5e_macsec_cleanup_sa need to wait for datapath to finish current
+ * Rx related data propagating using xa_erase which uses rcu to sync,
+ * once fs_id is erased then this rx_sc is hidden from datapath.
+ */
 	list_del_rcu(&rx_sc->rx_sc_list_element);
 	xa_erase(&macsec->sc_xarray, rx_sc->sc_xarray_element->fs_id);
+	metadata_dst_free(rx_sc->md_dst);
 	kfree(rx_sc->sc_xarray_element);
 
 	kfree_rcu(rx_sc);
@@ -821,6 +837,34 @@ void mlx5e_macsec_tx_build_eseg(struct mlx5e_macsec *macsec,
 	eseg->flow_table_metadata = cpu_to_be32(MLX5_ETH_WQE_FT_META_MACSEC | fs_id << 2);
 }
 
+void mlx5e_macsec_offload_handle_rx_skb(struct net_device *netdev,
+					struct sk_buff *skb,
+					struct mlx5_cqe64 *cqe)
+{
+	struct mlx5e_macsec_rx_sc_xarray_element *sc_xarray_element;
+	u32 macsec_meta_data = be32_to_cpu(cqe->ft_metadata);
+	struct mlx5e_priv *priv = netdev_priv(netdev);
+	struct mlx5e_macsec_rx_sc *rx_sc;
+	struct mlx5e_macsec *macsec;
+	u32  fs_id;
+
+	macsec = priv->macsec;
+	if (!macsec)
+		return;
+
+	fs_id = MLX5_MACSEC_METADATA_HANDLE(macsec_meta_data);
+
+	rcu_read_lock();
+	sc_xarray_element = xa_load(&macsec->sc_xarray, fs_id);
+	rx_sc = sc_xarray_element->rx_sc;
+	if (rx_sc) {
+		dst_hold(&rx_sc->md_dst->dst);
+		skb_dst_set(skb, &rx_sc->md_dst->dst);
+	}
+
+	rcu_read_unlock();
+}
+
 void mlx5e_macsec_build_netdev(struct mlx5e_priv *priv)
 {
 	struct net_device *netdev = priv->netdev;

drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.h

@@ -10,6 +10,10 @@
 #include <net/macsec.h>
 #include <net/dst_metadata.h>
 
+/* Bit31 - 30: MACsec marker, Bit3-0: MACsec id */
+#define MLX5_MACSEC_METADATA_MARKER(metadata)  ((((metadata) >> 30) & 0x3)  == 0x1)
+#define MLX5_MACSEC_METADATA_HANDLE(metadata)  ((metadata) & GENMASK(3, 0))
+
 struct mlx5e_priv;
 struct mlx5e_macsec;
 
@@ -28,12 +32,25 @@ static inline bool mlx5e_macsec_skb_is_offload(struct sk_buff *skb)
 	return md_dst && (md_dst->type == METADATA_MACSEC);
 }
 
+static inline bool mlx5e_macsec_is_rx_flow(struct mlx5_cqe64 *cqe)
+{
+	return MLX5_MACSEC_METADATA_MARKER(be32_to_cpu(cqe->ft_metadata));
+}
+
+void mlx5e_macsec_offload_handle_rx_skb(struct net_device *netdev, struct sk_buff *skb,
+					struct mlx5_cqe64 *cqe);
+
 #else
 
 static inline void mlx5e_macsec_build_netdev(struct mlx5e_priv *priv) {}
 static inline int mlx5e_macsec_init(struct mlx5e_priv *priv) { return 0; }
 static inline void mlx5e_macsec_cleanup(struct mlx5e_priv *priv) {}
 static inline bool mlx5e_macsec_skb_is_offload(struct sk_buff *skb) { return false; }
+static inline bool mlx5e_macsec_is_rx_flow(struct mlx5_cqe64 *cqe) { return false; }
+static inline void mlx5e_macsec_offload_handle_rx_skb(struct net_device *netdev,
+						      struct sk_buff *skb,
+						      struct mlx5_cqe64 *cqe)
+{}
 
 #endif  /* CONFIG_MLX5_EN_MACSEC */
 

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -49,6 +49,7 @@
 #include "en/rep/tc.h"
 #include "ipoib/ipoib.h"
 #include "en_accel/ipsec.h"
+#include "en_accel/macsec.h"
 #include "en_accel/ipsec_rxtx.h"
 #include "en_accel/ktls_txrx.h"
 #include "en/xdp.h"
@@ -1421,6 +1422,9 @@ static inline void mlx5e_build_rx_skb(struct mlx5_cqe64 *cqe,
 	if (unlikely(mlx5_ipsec_is_rx_flow(cqe)))
 		mlx5e_ipsec_offload_handle_rx_skb(netdev, skb, cqe);
 
+	if (unlikely(mlx5e_macsec_is_rx_flow(cqe)))
+		mlx5e_macsec_offload_handle_rx_skb(netdev, skb, cqe);
+
 	if (lro_num_seg > 1) {
 		mlx5e_lro_update_hdr(skb, cqe, cqe_bcnt);
 		skb_shinfo(skb)->gso_size = DIV_ROUND_UP(cqe_bcnt, lro_num_seg);