net/mlx5e: Support IPsec NAT-T functionality

Extend mlx5 IPsec packet offload to support UDP encapsulation
of IPsec ESP packets.
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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

@@ -354,6 +354,12 @@ void mlx5e_ipsec_build_accel_xfrm_attrs(struct mlx5e_ipsec_sa_entry *sa_entry,
 
 	mlx5e_ipsec_init_limits(sa_entry, attrs);
 	mlx5e_ipsec_init_macs(sa_entry, attrs);
+
+	if (x->encap) {
+		attrs->encap = true;
+		attrs->sport = x->encap->encap_sport;
+		attrs->dport = x->encap->encap_dport;
+	}
 }
 
 static int mlx5e_xfrm_validate_state(struct mlx5_core_dev *mdev,
@@ -387,8 +393,25 @@ static int mlx5e_xfrm_validate_state(struct mlx5_core_dev *mdev,
 		return -EINVAL;
 	}
 	if (x->encap) {
-		NL_SET_ERR_MSG_MOD(extack, "Encapsulated xfrm state may not be offloaded");
-		return -EINVAL;
+		if (!(mlx5_ipsec_device_caps(mdev) & MLX5_IPSEC_CAP_ESPINUDP)) {
+			NL_SET_ERR_MSG_MOD(extack, "Encapsulation is not supported");
+			return -EINVAL;
+		}
+
+		if (x->encap->encap_type != UDP_ENCAP_ESPINUDP) {
+			NL_SET_ERR_MSG_MOD(extack, "Encapsulation other than UDP is not supported");
+			return -EINVAL;
+		}
+
+		if (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) {
+			NL_SET_ERR_MSG_MOD(extack, "Encapsulation is supported in packet offload mode only");
+			return -EINVAL;
+		}
+
+		if (x->props.mode != XFRM_MODE_TRANSPORT) {
+			NL_SET_ERR_MSG_MOD(extack, "Encapsulation is supported in transport mode only");
+			return -EINVAL;
+		}
 	}
 	if (!x->aead) {
 		NL_SET_ERR_MSG_MOD(extack, "Cannot offload xfrm states without aead");

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

@@ -94,13 +94,20 @@ struct mlx5_accel_esp_xfrm_attrs {
 	u8 dir : 2;
 	u8 type : 2;
 	u8 drop : 1;
+	u8 encap : 1;
 	u8 family;
 	struct mlx5_replay_esn replay_esn;
 	u32 authsize;
 	u32 reqid;
 	struct mlx5_ipsec_lft lft;
-	u8 smac[ETH_ALEN];
-	u8 dmac[ETH_ALEN];
+	union {
+		u8 smac[ETH_ALEN];
+		__be16 sport;
+	};
+	union {
+		u8 dmac[ETH_ALEN];
+		__be16 dport;
+	};
 };
 
 enum mlx5_ipsec_cap {

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

@@ -951,37 +951,70 @@ setup_pkt_tunnel_reformat(struct mlx5_core_dev *mdev,
 	return -EINVAL;
 }
 
+static int get_reformat_type(struct mlx5_accel_esp_xfrm_attrs *attrs)
+{
+	switch (attrs->dir) {
+	case XFRM_DEV_OFFLOAD_IN:
+		if (attrs->encap)
+			return MLX5_REFORMAT_TYPE_DEL_ESP_TRANSPORT_OVER_UDP;
+		return MLX5_REFORMAT_TYPE_DEL_ESP_TRANSPORT;
+	case XFRM_DEV_OFFLOAD_OUT:
+		if (attrs->family == AF_INET) {
+			if (attrs->encap)
+				return MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_UDPV4;
+			return MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_IPV4;
+		}
+
+		if (attrs->encap)
+			return MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_UDPV6;
+		return MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_IPV6;
+	default:
+		WARN_ON(true);
+	}
+
+	return -EINVAL;
+}
+
 static int
 setup_pkt_transport_reformat(struct mlx5_accel_esp_xfrm_attrs *attrs,
 			     struct mlx5_pkt_reformat_params *reformat_params)
 {
-	u8 *reformatbf;
+	struct udphdr *udphdr;
+	char *reformatbf;
+	size_t bfflen;
 	__be32 spi;
+	void *hdr;
+
+	reformat_params->type = get_reformat_type(attrs);
+	if (reformat_params->type < 0)
+		return reformat_params->type;
 
 	switch (attrs->dir) {
 	case XFRM_DEV_OFFLOAD_IN:
-		reformat_params->type = MLX5_REFORMAT_TYPE_DEL_ESP_TRANSPORT;
 		break;
 	case XFRM_DEV_OFFLOAD_OUT:
-		if (attrs->family == AF_INET)
-			reformat_params->type =
-				MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_IPV4;
-		else
-			reformat_params->type =
-				MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_OVER_IPV6;
-
-		reformatbf = kzalloc(MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_SIZE,
-				     GFP_KERNEL);
+		bfflen = MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_SIZE;
+		if (attrs->encap)
+			bfflen += sizeof(*udphdr);
+
+		reformatbf = kzalloc(bfflen, GFP_KERNEL);
 		if (!reformatbf)
 			return -ENOMEM;
 
+		hdr = reformatbf;
+		if (attrs->encap) {
+			udphdr = (struct udphdr *)reformatbf;
+			udphdr->source = attrs->sport;
+			udphdr->dest = attrs->dport;
+			hdr += sizeof(*udphdr);
+		}
+
 		/* convert to network format */
 		spi = htonl(attrs->spi);
-		memcpy(reformatbf, &spi, sizeof(spi));
+		memcpy(hdr, &spi, sizeof(spi));
 
 		reformat_params->param_0 = attrs->authsize;
-		reformat_params->size =
-			MLX5_REFORMAT_TYPE_ADD_ESP_TRANSPORT_SIZE;
+		reformat_params->size = bfflen;
 		reformat_params->data = reformatbf;
 		break;
 	default: