Merge branch 'net-tja11xx-macsec-support'

Radu Pirea says:

====================
Add MACsec support for TJA11XX C45 PHYs

This is the MACsec support for TJA11XX PHYs. The MACsec block encrypts
the ethernet frames on the fly and has no buffering. This operation will
grow the frames by 32 bytes. If the frames are sent back to back, the
MACsec block will not have enough room to insert the SecTAG and the ICV
and the frames will be dropped.

To mitigate this, the PHY can parse a specific ethertype with some
padding bytes and replace them with the SecTAG and ICV. These padding
bytes might be dummy or might contain information about TX SC that must
be used to encrypt the frame.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 114 insertions, 37 deletions

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 9663050a852d..e34816638569 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -93,6 +93,8 @@ struct pcpu_secy_stats {
  * @secys: linked list of SecY's on the underlying device
  * @gro_cells: pointer to the Generic Receive Offload cell
  * @offload: status of offloading on the MACsec device
+ * @insert_tx_tag: when offloading, device requires to insert an
+ *	additional tag
  */
 struct macsec_dev {
 	struct macsec_secy secy;
@@ -102,6 +104,7 @@ struct macsec_dev {
 	struct list_head secys;
 	struct gro_cells gro_cells;
 	enum macsec_offload offload;
+	bool insert_tx_tag;
 };
 
 /**
@@ -604,26 +607,11 @@ static struct sk_buff *macsec_encrypt(struct sk_buff *skb,
 		return ERR_PTR(-EINVAL);
 	}
 
-	if (unlikely(skb_headroom(skb) < MACSEC_NEEDED_HEADROOM ||
-		     skb_tailroom(skb) < MACSEC_NEEDED_TAILROOM)) {
-		struct sk_buff *nskb = skb_copy_expand(skb,
-						       MACSEC_NEEDED_HEADROOM,
-						       MACSEC_NEEDED_TAILROOM,
-						       GFP_ATOMIC);
-		if (likely(nskb)) {
-			consume_skb(skb);
-			skb = nskb;
-		} else {
-			macsec_txsa_put(tx_sa);
-			kfree_skb(skb);
-			return ERR_PTR(-ENOMEM);
-		}
-	} else {
-		skb = skb_unshare(skb, GFP_ATOMIC);
-		if (!skb) {
-			macsec_txsa_put(tx_sa);
-			return ERR_PTR(-ENOMEM);
-		}
+	ret = skb_ensure_writable_head_tail(skb, dev);
+	if (unlikely(ret < 0)) {
+		macsec_txsa_put(tx_sa);
+		kfree_skb(skb);
+		return ERR_PTR(ret);
 	}
 
 	unprotected_len = skb->len;
@@ -2583,6 +2571,33 @@ static bool macsec_is_configured(struct macsec_dev *macsec)
 	return false;
 }
 
+static bool macsec_needs_tx_tag(struct macsec_dev *macsec,
+				const struct macsec_ops *ops)
+{
+	return macsec->offload == MACSEC_OFFLOAD_PHY &&
+		ops->mdo_insert_tx_tag;
+}
+
+static void macsec_set_head_tail_room(struct net_device *dev)
+{
+	struct macsec_dev *macsec = macsec_priv(dev);
+	struct net_device *real_dev = macsec->real_dev;
+	int needed_headroom, needed_tailroom;
+	const struct macsec_ops *ops;
+
+	ops = macsec_get_ops(macsec, NULL);
+	if (ops) {
+		needed_headroom = ops->needed_headroom;
+		needed_tailroom = ops->needed_tailroom;
+	} else {
+		needed_headroom = MACSEC_NEEDED_HEADROOM;
+		needed_tailroom = MACSEC_NEEDED_TAILROOM;
+	}
+
+	dev->needed_headroom = real_dev->needed_headroom + needed_headroom;
+	dev->needed_tailroom = real_dev->needed_tailroom + needed_tailroom;
+}
+
 static int macsec_update_offload(struct net_device *dev, enum macsec_offload offload)
 {
 	enum macsec_offload prev_offload;
@@ -2620,8 +2635,13 @@ static int macsec_update_offload(struct net_device *dev, enum macsec_offload off
 	ctx.secy = &macsec->secy;
 	ret = offload == MACSEC_OFFLOAD_OFF ? macsec_offload(ops->mdo_del_secy, &ctx)
 					    : macsec_offload(ops->mdo_add_secy, &ctx);
-	if (ret)
+	if (ret) {
 		macsec->offload = prev_offload;
+		return ret;
+	}
+
+	macsec_set_head_tail_room(dev);
+	macsec->insert_tx_tag = macsec_needs_tx_tag(macsec, ops);
 
 	return ret;
 }
@@ -3379,6 +3399,40 @@ static struct genl_family macsec_fam __ro_after_init = {
 	.resv_start_op	= MACSEC_CMD_UPD_OFFLOAD + 1,
 };
 
+static struct sk_buff *macsec_insert_tx_tag(struct sk_buff *skb,
+					    struct net_device *dev)
+{
+	struct macsec_dev *macsec = macsec_priv(dev);
+	const struct macsec_ops *ops;
+	struct phy_device *phydev;
+	struct macsec_context ctx;
+	int skb_final_len;
+	int err;
+
+	ops = macsec_get_ops(macsec, &ctx);
+	skb_final_len = skb->len - ETH_HLEN + ops->needed_headroom +
+		ops->needed_tailroom;
+	if (unlikely(skb_final_len > macsec->real_dev->mtu)) {
+		err = -EINVAL;
+		goto cleanup;
+	}
+
+	phydev = macsec->real_dev->phydev;
+
+	err = skb_ensure_writable_head_tail(skb, dev);
+	if (unlikely(err < 0))
+		goto cleanup;
+
+	err = ops->mdo_insert_tx_tag(phydev, skb);
+	if (unlikely(err))
+		goto cleanup;
+
+	return skb;
+cleanup:
+	kfree_skb(skb);
+	return ERR_PTR(err);
+}
+
 static netdev_tx_t macsec_start_xmit(struct sk_buff *skb,
 				     struct net_device *dev)
 {
@@ -3393,6 +3447,15 @@ static netdev_tx_t macsec_start_xmit(struct sk_buff *skb,
 		skb_dst_drop(skb);
 		dst_hold(&md_dst->dst);
 		skb_dst_set(skb, &md_dst->dst);
+
+		if (macsec->insert_tx_tag) {
+			skb = macsec_insert_tx_tag(skb, dev);
+			if (IS_ERR(skb)) {
+				DEV_STATS_INC(dev, tx_dropped);
+				return NETDEV_TX_OK;
+			}
+		}
+
 		skb->dev = macsec->real_dev;
 		return dev_queue_xmit(skb);
 	}
@@ -3454,10 +3517,7 @@ static int macsec_dev_init(struct net_device *dev)
 	dev->features = real_dev->features & MACSEC_FEATURES;
 	dev->features |= NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE;
 
-	dev->needed_headroom = real_dev->needed_headroom +
-			       MACSEC_NEEDED_HEADROOM;
-	dev->needed_tailroom = real_dev->needed_tailroom +
-			       MACSEC_NEEDED_TAILROOM;
+	macsec_set_head_tail_room(dev);
 
 	if (is_zero_ether_addr(dev->dev_addr))
 		eth_hw_addr_inherit(dev, real_dev);
@@ -3604,21 +3664,19 @@ static int macsec_set_mac_address(struct net_device *dev, void *p)
 	struct macsec_dev *macsec = macsec_priv(dev);
 	struct net_device *real_dev = macsec->real_dev;
 	struct sockaddr *addr = p;
+	u8  old_addr[ETH_ALEN];
 	int err;
 
 	if (!is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 
-	if (!(dev->flags & IFF_UP))
-		goto out;
-
-	err = dev_uc_add(real_dev, addr->sa_data);
-	if (err < 0)
-		return err;
-
-	dev_uc_del(real_dev, dev->dev_addr);
+	if (dev->flags & IFF_UP) {
+		err = dev_uc_add(real_dev, addr->sa_data);
+		if (err < 0)
+			return err;
+	}
 
-out:
+	ether_addr_copy(old_addr, dev->dev_addr);
 	eth_hw_addr_set(dev, addr->sa_data);
 
 	/* If h/w offloading is available, propagate to the device */
@@ -3627,13 +3685,29 @@ out:
 		struct macsec_context ctx;
 
 		ops = macsec_get_ops(macsec, &ctx);
-		if (ops) {
-			ctx.secy = &macsec->secy;
-			macsec_offload(ops->mdo_upd_secy, &ctx);
+		if (!ops) {
+			err = -EOPNOTSUPP;
+			goto restore_old_addr;
 		}
+
+		ctx.secy = &macsec->secy;
+		err = macsec_offload(ops->mdo_upd_secy, &ctx);
+		if (err)
+			goto restore_old_addr;
 	}
 
+	if (dev->flags & IFF_UP)
+		dev_uc_del(real_dev, old_addr);
+
 	return 0;
+
+restore_old_addr:
+	if (dev->flags & IFF_UP)
+		dev_uc_del(real_dev, addr->sa_data);
+
+	eth_hw_addr_set(dev, old_addr);
+
+	return err;
 }
 
 static int macsec_change_mtu(struct net_device *dev, int new_mtu)
@@ -4126,6 +4200,9 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 			err = macsec_offload(ops->mdo_add_secy, &ctx);
 			if (err)
 				goto del_dev;
+
+			macsec->insert_tx_tag =
+				macsec_needs_tx_tag(macsec, ops);
 		}
 	}