net: macsec: add support for offloading to the MAC

This patch adds a new MACsec offloading option, MACSEC_OFFLOAD_MAC,
allowing a user to select a MAC as a provider for MACsec offloading
operations.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macsec.c

@@ -339,7 +339,8 @@ static void macsec_set_shortlen(struct macsec_eth_header *h, size_t data_len)
 /* Checks if a MACsec interface is being offloaded to an hardware engine */
 static bool macsec_is_offloaded(struct macsec_dev *macsec)
 {
-	if (macsec->offload == MACSEC_OFFLOAD_PHY)
+	if (macsec->offload == MACSEC_OFFLOAD_MAC ||
+	    macsec->offload == MACSEC_OFFLOAD_PHY)
 		return true;
 
 	return false;
@@ -355,6 +356,9 @@ static bool macsec_check_offload(enum macsec_offload offload,
 	if (offload == MACSEC_OFFLOAD_PHY)
 		return macsec->real_dev->phydev &&
 		       macsec->real_dev->phydev->macsec_ops;
+	else if (offload == MACSEC_OFFLOAD_MAC)
+		return macsec->real_dev->features & NETIF_F_HW_MACSEC &&
+		       macsec->real_dev->macsec_ops;
 
 	return false;
 }
@@ -369,9 +373,14 @@ static const struct macsec_ops *__macsec_get_ops(enum macsec_offload offload,
 
 		if (offload == MACSEC_OFFLOAD_PHY)
 			ctx->phydev = macsec->real_dev->phydev;
+		else if (offload == MACSEC_OFFLOAD_MAC)
+			ctx->netdev = macsec->real_dev;
 	}
 
+	if (offload == MACSEC_OFFLOAD_PHY)
 		return macsec->real_dev->phydev->macsec_ops;
+	else
+		return macsec->real_dev->macsec_ops;
 }
 
 /* Returns a pointer to the MACsec ops struct if any and updates the MACsec

include/uapi/linux/if_link.h

@@ -489,6 +489,7 @@ enum macsec_validation_type {
 enum macsec_offload {
 	MACSEC_OFFLOAD_OFF = 0,
 	MACSEC_OFFLOAD_PHY = 1,
+	MACSEC_OFFLOAD_MAC = 2,
 	__MACSEC_OFFLOAD_END,
 	MACSEC_OFFLOAD_MAX = __MACSEC_OFFLOAD_END - 1,
 };

tools/include/uapi/linux/if_link.h

@@ -489,6 +489,7 @@ enum macsec_validation_type {
 enum macsec_offload {
 	MACSEC_OFFLOAD_OFF = 0,
 	MACSEC_OFFLOAD_PHY = 1,
+	MACSEC_OFFLOAD_MAC = 2,
 	__MACSEC_OFFLOAD_END,
 	MACSEC_OFFLOAD_MAX = __MACSEC_OFFLOAD_END - 1,
 };