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

MACsec driver marks Tx packets for device offload using a dedicated
skb_metadata_dst which holds a 64 bits SCI number.
A previously set rule will match on this number so the correct SA is used
for the MACsec operation.
As device driver can only provide 32 bits of metadata to flow tables,
need to used a mapping from 64 bit to 32 bits marker or id,
which is can be achieved by provide a 32 bit unique flow id in the
control path, and used a hash table to map 64 bit to the unique id in the
datapath.

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/en_accel.h

@@ -39,6 +39,7 @@
 #include "en_accel/ipsec_rxtx.h"
 #include "en_accel/ktls.h"
 #include "en_accel/ktls_txrx.h"
+#include <en_accel/macsec.h>
 #include "en.h"
 #include "en/txrx.h"
 
@@ -137,6 +138,15 @@ static inline bool mlx5e_accel_tx_begin(struct net_device *dev,
 	}
 #endif
 
+#ifdef CONFIG_MLX5_EN_MACSEC
+	if (unlikely(mlx5e_macsec_skb_is_offload(skb))) {
+		struct mlx5e_priv *priv = netdev_priv(dev);
+
+		if (unlikely(!mlx5e_macsec_handle_tx_skb(priv->macsec, skb)))
+			return false;
+	}
+#endif
+
 	return true;
 }
 
@@ -163,6 +173,11 @@ static inline void mlx5e_accel_tx_eseg(struct mlx5e_priv *priv,
 		mlx5e_ipsec_tx_build_eseg(priv, skb, eseg);
 #endif
 
+#ifdef CONFIG_MLX5_EN_MACSEC
+	if (unlikely(mlx5e_macsec_skb_is_offload(skb)))
+		mlx5e_macsec_tx_build_eseg(priv->macsec, skb, eseg);
+#endif
+
 #if IS_ENABLED(CONFIG_GENEVE)
 	if (skb->encapsulation && skb->ip_summed == CHECKSUM_PARTIAL)
 		mlx5e_tx_tunnel_accel(skb, eseg, ihs);

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

@@ -20,7 +20,18 @@ struct mlx5e_macsec_sa {
 	u32 next_pn;
 	sci_t sci;
 
+	struct rhash_head hash;
+	u32 fs_id;
 	struct mlx5e_macsec_tx_rule *tx_rule;
+	struct rcu_head rcu_head;
+};
+
+static const struct rhashtable_params rhash_sci = {
+	.key_len = sizeof_field(struct mlx5e_macsec_sa, sci),
+	.key_offset = offsetof(struct mlx5e_macsec_sa, sci),
+	.head_offset = offsetof(struct mlx5e_macsec_sa, hash),
+	.automatic_shrinking = true,
+	.min_size = 1,
 };
 
 struct mlx5e_macsec {
@@ -31,6 +42,9 @@ struct mlx5e_macsec {
 	/* Global PD for MACsec object ASO context */
 	u32 aso_pdn;
 
+	/* Tx sci -> fs id mapping handling */
+	struct rhashtable sci_hash;      /* sci -> mlx5e_macsec_sa */
+
 	struct mlx5_core_dev *mdev;
 };
 
@@ -96,6 +110,11 @@ static void mlx5e_macsec_destroy_object(struct mlx5_core_dev *mdev, u32 macsec_o
 
 static void mlx5e_macsec_cleanup_sa(struct mlx5e_macsec *macsec, struct mlx5e_macsec_sa *sa)
 {
+	if (sa->fs_id) {
+		/* Make sure ongoing datapath readers sees a valid SA */
+		rhashtable_remove_fast(&macsec->sci_hash, &sa->hash, rhash_sci);
+		sa->fs_id = 0;
+	}
 
 	if (!sa->tx_rule)
 		return;
@@ -131,14 +150,19 @@ static int mlx5e_macsec_init_sa(struct macsec_context *ctx,
 	rule_attrs.macsec_obj_id = sa->macsec_obj_id;
 	rule_attrs.action = MLX5_ACCEL_MACSEC_ACTION_ENCRYPT;
 
-	tx_rule = mlx5e_macsec_fs_add_rule(macsec->macsec_fs, ctx, &rule_attrs);
+	tx_rule = mlx5e_macsec_fs_add_rule(macsec->macsec_fs, ctx, &rule_attrs, &sa->fs_id);
 	if (IS_ERR_OR_NULL(tx_rule))
 		goto destroy_macsec_object;
 
-	sa->tx_rule = tx_rule;
+	err = rhashtable_insert_fast(&macsec->sci_hash, &sa->hash, rhash_sci);
+	if (err)
+		goto destroy_macsec_rule;
 
+	sa->tx_rule = tx_rule;
 	return 0;
 
+destroy_macsec_rule:
+	mlx5e_macsec_fs_del_rule(macsec->macsec_fs, tx_rule, MLX5_ACCEL_MACSEC_ACTION_ENCRYPT);
 destroy_macsec_object:
 	mlx5e_macsec_destroy_object(mdev, sa->macsec_obj_id);
 
@@ -295,7 +319,7 @@ static int mlx5e_macsec_del_txsa(struct macsec_context *ctx)
 
 	mlx5e_macsec_cleanup_sa(macsec, tx_sa);
 	mlx5_destroy_encryption_key(macsec->mdev, tx_sa->enc_key_id);
-	kfree(tx_sa);
+	kfree_rcu(tx_sa);
 	macsec->tx_sa[assoc_num] = NULL;
 
 out:
@@ -304,6 +328,20 @@ static int mlx5e_macsec_del_txsa(struct macsec_context *ctx)
 	return err;
 }
 
+static u32 mlx5e_macsec_get_sa_from_hashtable(struct rhashtable *sci_hash, sci_t *sci)
+{
+	struct mlx5e_macsec_sa *macsec_sa;
+	u32 fs_id = 0;
+
+	rcu_read_lock();
+	macsec_sa = rhashtable_lookup(sci_hash, sci, rhash_sci);
+	if (macsec_sa)
+		fs_id = macsec_sa->fs_id;
+	rcu_read_unlock();
+
+	return fs_id;
+}
+
 static bool mlx5e_is_macsec_device(const struct mlx5_core_dev *mdev)
 {
 	if (!(MLX5_CAP_GEN_64(mdev, general_obj_types) &
@@ -341,6 +379,36 @@ static const struct macsec_ops macsec_offload_ops = {
 	.mdo_del_txsa = mlx5e_macsec_del_txsa,
 };
 
+bool mlx5e_macsec_handle_tx_skb(struct mlx5e_macsec *macsec, struct sk_buff *skb)
+{
+	struct metadata_dst *md_dst = skb_metadata_dst(skb);
+	u32 fs_id;
+
+	fs_id = mlx5e_macsec_get_sa_from_hashtable(&macsec->sci_hash, &md_dst->u.macsec_info.sci);
+	if (!fs_id)
+		goto err_out;
+
+	return true;
+
+err_out:
+	dev_kfree_skb_any(skb);
+	return false;
+}
+
+void mlx5e_macsec_tx_build_eseg(struct mlx5e_macsec *macsec,
+				struct sk_buff *skb,
+				struct mlx5_wqe_eth_seg *eseg)
+{
+	struct metadata_dst *md_dst = skb_metadata_dst(skb);
+	u32 fs_id;
+
+	fs_id = mlx5e_macsec_get_sa_from_hashtable(&macsec->sci_hash, &md_dst->u.macsec_info.sci);
+	if (!fs_id)
+		return;
+
+	eseg->flow_table_metadata = cpu_to_be32(MLX5_ETH_WQE_FT_META_MACSEC | fs_id << 2);
+}
+
 void mlx5e_macsec_build_netdev(struct mlx5e_priv *priv)
 {
 	struct net_device *netdev = priv->netdev;
@@ -381,6 +449,13 @@ int mlx5e_macsec_init(struct mlx5e_priv *priv)
 		goto err_pd;
 	}
 
+	err = rhashtable_init(&macsec->sci_hash, &rhash_sci);
+	if (err) {
+		mlx5_core_err(mdev, "MACsec offload: Failed to init SCI hash table, err=%d\n",
+			      err);
+		goto err_out;
+	}
+
 	priv->macsec = macsec;
 
 	macsec->mdev = mdev;
@@ -416,6 +491,8 @@ void mlx5e_macsec_cleanup(struct mlx5e_priv *priv)
 
 	mlx5_core_dealloc_pd(priv->mdev, macsec->aso_pdn);
 
+	rhashtable_destroy(&macsec->sci_hash);
+
 	mutex_destroy(&macsec->lock);
 
 	kfree(macsec);

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

@@ -8,18 +8,32 @@
 
 #include <linux/mlx5/driver.h>
 #include <net/macsec.h>
+#include <net/dst_metadata.h>
 
 struct mlx5e_priv;
+struct mlx5e_macsec;
 
 void mlx5e_macsec_build_netdev(struct mlx5e_priv *priv);
 int mlx5e_macsec_init(struct mlx5e_priv *priv);
 void mlx5e_macsec_cleanup(struct mlx5e_priv *priv);
+bool mlx5e_macsec_handle_tx_skb(struct mlx5e_macsec *macsec, struct sk_buff *skb);
+void mlx5e_macsec_tx_build_eseg(struct mlx5e_macsec *macsec,
+				struct sk_buff *skb,
+				struct mlx5_wqe_eth_seg *eseg);
+
+static inline bool mlx5e_macsec_skb_is_offload(struct sk_buff *skb)
+{
+	struct metadata_dst *md_dst = skb_metadata_dst(skb);
+
+	return md_dst && (md_dst->type == METADATA_MACSEC);
+}
 
 #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; }
 
 #endif  /* CONFIG_MLX5_EN_MACSEC */
 

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

@@ -464,7 +464,8 @@ static void macsec_fs_tx_del_rule(struct mlx5e_macsec_fs *macsec_fs,
 static struct mlx5e_macsec_tx_rule *
 macsec_fs_tx_add_rule(struct mlx5e_macsec_fs *macsec_fs,
 		      const struct macsec_context *macsec_ctx,
-		      struct mlx5_macsec_rule_attrs *attrs)
+		      struct mlx5_macsec_rule_attrs *attrs,
+		      u32 *sa_fs_id)
 {
 	char reformatbf[MLX5_MACSEC_TAG_LEN + MACSEC_SCI_LEN];
 	struct mlx5_pkt_reformat_params reformat_params = {};
@@ -518,6 +519,7 @@ macsec_fs_tx_add_rule(struct mlx5e_macsec_fs *macsec_fs,
 	}
 
 	tx_rule->fs_id = fs_id;
+	*sa_fs_id = fs_id;
 
 	flow_act.action = MLX5_FLOW_CONTEXT_ACTION_FWD_DEST |
 			  MLX5_FLOW_CONTEXT_ACTION_CRYPTO_ENCRYPT |
@@ -626,10 +628,11 @@ static int macsec_fs_tx_init(struct mlx5e_macsec_fs *macsec_fs)
 struct mlx5e_macsec_tx_rule *
 mlx5e_macsec_fs_add_rule(struct mlx5e_macsec_fs *macsec_fs,
 			 const struct macsec_context *macsec_ctx,
-			 struct mlx5_macsec_rule_attrs *attrs)
+			 struct mlx5_macsec_rule_attrs *attrs,
+			 u32 *sa_fs_id)
 {
 	if (attrs->action == MLX5_ACCEL_MACSEC_ACTION_ENCRYPT)
-		return macsec_fs_tx_add_rule(macsec_fs, macsec_ctx, attrs);
+		return macsec_fs_tx_add_rule(macsec_fs, macsec_ctx, attrs, sa_fs_id);
 
 	return NULL;
 }

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

@@ -30,7 +30,8 @@ mlx5e_macsec_fs_init(struct mlx5_core_dev *mdev, struct net_device *netdev);
 struct mlx5e_macsec_tx_rule *
 mlx5e_macsec_fs_add_rule(struct mlx5e_macsec_fs *macsec_fs,
 			 const struct macsec_context *ctx,
-			 struct mlx5_macsec_rule_attrs *attrs);
+			 struct mlx5_macsec_rule_attrs *attrs,
+			 u32 *sa_fs_id);
 
 void mlx5e_macsec_fs_del_rule(struct mlx5e_macsec_fs *macsec_fs,
 			      struct mlx5e_macsec_tx_rule *macsec_rule,

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

@@ -39,6 +39,7 @@
 #include "ipoib/ipoib.h"
 #include "en_accel/en_accel.h"
 #include "en_accel/ipsec_rxtx.h"
+#include "en_accel/macsec.h"
 #include "en/ptp.h"
 #include <net/ipv6.h>
 
@@ -485,7 +486,7 @@ mlx5e_sq_xmit_wqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 static bool mlx5e_tx_skb_supports_mpwqe(struct sk_buff *skb, struct mlx5e_tx_attr *attr)
 {
 	return !skb_is_nonlinear(skb) && !skb_vlan_tag_present(skb) && !attr->ihs &&
-	       !attr->insz;
+	       !attr->insz && !mlx5e_macsec_skb_is_offload(skb);
 }
 
 static bool mlx5e_tx_mpwqe_same_eseg(struct mlx5e_txqsq *sq, struct mlx5_wqe_eth_seg *eseg)