net/mlx5e: Support IPsec RX packet offload in tunnel mode

Extend mlx5 driver with logic to support IPsec RX packet offload
in tunnel mode.
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -242,6 +242,41 @@ static void mlx5e_ipsec_init_limits(struct mlx5e_ipsec_sa_entry *sa_entry,
 	attrs->lft.numb_rounds_soft = (u64)n;
 }
 
+static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
+				  struct mlx5_accel_esp_xfrm_attrs *attrs)
+{
+	struct mlx5_core_dev *mdev = mlx5e_ipsec_sa2dev(sa_entry);
+	struct xfrm_state *x = sa_entry->x;
+	struct net_device *netdev;
+	struct neighbour *n;
+	u8 addr[ETH_ALEN];
+
+	if (attrs->mode != XFRM_MODE_TUNNEL &&
+	    attrs->type != XFRM_DEV_OFFLOAD_PACKET)
+		return;
+
+	netdev = x->xso.real_dev;
+
+	mlx5_query_mac_address(mdev, addr);
+	switch (attrs->dir) {
+	case XFRM_DEV_OFFLOAD_IN:
+		ether_addr_copy(attrs->dmac, addr);
+		n = neigh_lookup(&arp_tbl, &attrs->saddr.a4, netdev);
+		if (!n) {
+			n = neigh_create(&arp_tbl, &attrs->saddr.a4, netdev);
+			if (IS_ERR(n))
+				return;
+			neigh_event_send(n, NULL);
+		}
+		neigh_ha_snapshot(addr, n, netdev);
+		ether_addr_copy(attrs->smac, addr);
+		break;
+	default:
+		return;
+	}
+	neigh_release(n);
+}
+
 void mlx5e_ipsec_build_accel_xfrm_attrs(struct mlx5e_ipsec_sa_entry *sa_entry,
 					struct mlx5_accel_esp_xfrm_attrs *attrs)
 {
@@ -300,6 +335,7 @@ void mlx5e_ipsec_build_accel_xfrm_attrs(struct mlx5e_ipsec_sa_entry *sa_entry,
 	attrs->mode = x->props.mode;
 
 	mlx5e_ipsec_init_limits(sa_entry, attrs);
+	mlx5e_ipsec_init_macs(sa_entry, attrs);
 }
 
 static int mlx5e_xfrm_validate_state(struct mlx5_core_dev *mdev,

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

@@ -99,6 +99,8 @@ struct mlx5_accel_esp_xfrm_attrs {
 	u32 authsize;
 	u32 reqid;
 	struct mlx5_ipsec_lft lft;
+	u8 smac[ETH_ALEN];
+	u8 dmac[ETH_ALEN];
 };
 
 enum mlx5_ipsec_cap {

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

@@ -837,6 +837,53 @@ static int setup_modify_header(struct mlx5_core_dev *mdev, u32 val, u8 dir,
 	return 0;
 }
 
+static int
+setup_pkt_tunnel_reformat(struct mlx5_core_dev *mdev,
+			  struct mlx5_accel_esp_xfrm_attrs *attrs,
+			  struct mlx5_pkt_reformat_params *reformat_params)
+{
+	struct ethhdr *eth_hdr;
+	char *reformatbf;
+	size_t bfflen;
+
+	bfflen = sizeof(*eth_hdr);
+
+	reformatbf = kzalloc(bfflen, GFP_KERNEL);
+	if (!reformatbf)
+		return -ENOMEM;
+
+	eth_hdr = (struct ethhdr *)reformatbf;
+	switch (attrs->family) {
+	case AF_INET:
+		eth_hdr->h_proto = htons(ETH_P_IP);
+		break;
+	case AF_INET6:
+		eth_hdr->h_proto = htons(ETH_P_IPV6);
+		break;
+	default:
+		goto free_reformatbf;
+	}
+
+	ether_addr_copy(eth_hdr->h_dest, attrs->dmac);
+	ether_addr_copy(eth_hdr->h_source, attrs->smac);
+
+	switch (attrs->dir) {
+	case XFRM_DEV_OFFLOAD_IN:
+		reformat_params->type = MLX5_REFORMAT_TYPE_L3_ESP_TUNNEL_TO_L2;
+		break;
+	default:
+		goto free_reformatbf;
+	}
+
+	reformat_params->size = bfflen;
+	reformat_params->data = reformatbf;
+	return 0;
+
+free_reformatbf:
+	kfree(reformatbf);
+	return -EINVAL;
+}
+
 static int
 setup_pkt_transport_reformat(struct mlx5_accel_esp_xfrm_attrs *attrs,
 			     struct mlx5_pkt_reformat_params *reformat_params)
@@ -901,6 +948,9 @@ static int setup_pkt_reformat(struct mlx5_core_dev *mdev,
 	case XFRM_MODE_TRANSPORT:
 		ret = setup_pkt_transport_reformat(attrs, &reformat_params);
 		break;
+	case XFRM_MODE_TUNNEL:
+		ret = setup_pkt_tunnel_reformat(mdev, attrs, &reformat_params);
+		break;
 	default:
 		ret = -EINVAL;
 	}