net/mlx5e: Listen to ARP events to update IPsec L2 headers in tunnel mode

In IPsec packet offload mode all header manipulations are performed by
hardware, which is responsible to add/remove L2 header with source and
destinations MACs.

CX-7 devices don't support offload of in-kernel routing functionality,
as such HW needs external help to fill other side MAC as it isn't
available for HW.

As a solution, let's listen to neigh ARP updates and reconfigure IPsec
rules on the fly once new MAC data information arrives.
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

@@ -35,12 +35,14 @@
 #include <crypto/aead.h>
 #include <linux/inetdevice.h>
 #include <linux/netdevice.h>
+#include <net/netevent.h>
 
 #include "en.h"
 #include "ipsec.h"
 #include "ipsec_rxtx.h"
 
 #define MLX5_IPSEC_RESCHED msecs_to_jiffies(1000)
+#define MLX5E_IPSEC_TUNNEL_SA XA_MARK_1
 
 static struct mlx5e_ipsec_sa_entry *to_ipsec_sa_entry(struct xfrm_state *x)
 {
@@ -251,7 +253,7 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 	struct neighbour *n;
 	u8 addr[ETH_ALEN];
 
-	if (attrs->mode != XFRM_MODE_TUNNEL &&
+	if (attrs->mode != XFRM_MODE_TUNNEL ||
 	    attrs->type != XFRM_DEV_OFFLOAD_PACKET)
 		return;
 
@@ -267,6 +269,8 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 			if (IS_ERR(n))
 				return;
 			neigh_event_send(n, NULL);
+			attrs->drop = true;
+			break;
 		}
 		neigh_ha_snapshot(addr, n, netdev);
 		ether_addr_copy(attrs->smac, addr);
@@ -279,6 +283,8 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 			if (IS_ERR(n))
 				return;
 			neigh_event_send(n, NULL);
+			attrs->drop = true;
+			break;
 		}
 		neigh_ha_snapshot(addr, n, netdev);
 		ether_addr_copy(attrs->dmac, addr);
@@ -507,34 +513,81 @@ static void mlx5e_ipsec_set_esn_ops(struct mlx5e_ipsec_sa_entry *sa_entry)
 	sa_entry->set_iv_op = mlx5e_ipsec_set_iv;
 }
 
+static void mlx5e_ipsec_handle_netdev_event(struct work_struct *_work)
+{
+	struct mlx5e_ipsec_work *work =
+		container_of(_work, struct mlx5e_ipsec_work, work);
+	struct mlx5e_ipsec_sa_entry *sa_entry = work->sa_entry;
+	struct mlx5e_ipsec_netevent_data *data = work->data;
+	struct mlx5_accel_esp_xfrm_attrs *attrs;
+
+	attrs = &sa_entry->attrs;
+
+	switch (attrs->dir) {
+	case XFRM_DEV_OFFLOAD_IN:
+		ether_addr_copy(attrs->smac, data->addr);
+		break;
+	case XFRM_DEV_OFFLOAD_OUT:
+		ether_addr_copy(attrs->dmac, data->addr);
+		break;
+	default:
+		WARN_ON_ONCE(true);
+	}
+	attrs->drop = false;
+	mlx5e_accel_ipsec_fs_modify(sa_entry);
+}
+
 static int mlx5_ipsec_create_work(struct mlx5e_ipsec_sa_entry *sa_entry)
 {
 	struct xfrm_state *x = sa_entry->x;
 	struct mlx5e_ipsec_work *work;
+	void *data = NULL;
 
 	switch (x->xso.type) {
 	case XFRM_DEV_OFFLOAD_CRYPTO:
 		if (!(x->props.flags & XFRM_STATE_ESN))
 			return 0;
 		break;
-	default:
+	case XFRM_DEV_OFFLOAD_PACKET:
+		if (x->props.mode != XFRM_MODE_TUNNEL)
 			return 0;
+		break;
+	default:
+		break;
 	}
 
 	work = kzalloc(sizeof(*work), GFP_KERNEL);
 	if (!work)
 		return -ENOMEM;
 
-	work->data = kzalloc(sizeof(*sa_entry), GFP_KERNEL);
-	if (!work->data) {
-		kfree(work);
-		return -ENOMEM;
-	}
+	switch (x->xso.type) {
+	case XFRM_DEV_OFFLOAD_CRYPTO:
+		data = kzalloc(sizeof(*sa_entry), GFP_KERNEL);
+		if (!data)
+			goto free_work;
 
 		INIT_WORK(&work->work, mlx5e_ipsec_modify_state);
+		break;
+	case XFRM_DEV_OFFLOAD_PACKET:
+		data = kzalloc(sizeof(struct mlx5e_ipsec_netevent_data),
+			       GFP_KERNEL);
+		if (!data)
+			goto free_work;
+
+		INIT_WORK(&work->work, mlx5e_ipsec_handle_netdev_event);
+		break;
+	default:
+		break;
+	}
+
+	work->data = data;
 	work->sa_entry = sa_entry;
 	sa_entry->work = work;
 	return 0;
+
+free_work:
+	kfree(work);
+	return -ENOMEM;
 }
 
 static int mlx5e_ipsec_create_dwork(struct mlx5e_ipsec_sa_entry *sa_entry)
@@ -629,6 +682,12 @@ static int mlx5e_xfrm_add_state(struct xfrm_state *x,
 	if (sa_entry->dwork)
 		queue_delayed_work(ipsec->wq, &sa_entry->dwork->dwork,
 				   MLX5_IPSEC_RESCHED);
+
+	if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET &&
+	    x->props.mode == XFRM_MODE_TUNNEL)
+		xa_set_mark(&ipsec->sadb, sa_entry->ipsec_obj_id,
+			    MLX5E_IPSEC_TUNNEL_SA);
+
 out:
 	x->xso.offload_handle = (unsigned long)sa_entry;
 	return 0;
@@ -651,6 +710,7 @@ static int mlx5e_xfrm_add_state(struct xfrm_state *x,
 static void mlx5e_xfrm_del_state(struct xfrm_state *x)
 {
 	struct mlx5e_ipsec_sa_entry *sa_entry = to_ipsec_sa_entry(x);
+	struct mlx5_accel_esp_xfrm_attrs *attrs = &sa_entry->attrs;
 	struct mlx5e_ipsec *ipsec = sa_entry->ipsec;
 	struct mlx5e_ipsec_sa_entry *old;
 
@@ -659,6 +719,12 @@ static void mlx5e_xfrm_del_state(struct xfrm_state *x)
 
 	old = xa_erase_bh(&ipsec->sadb, sa_entry->ipsec_obj_id);
 	WARN_ON(old != sa_entry);
+
+	if (attrs->mode == XFRM_MODE_TUNNEL &&
+	    attrs->type == XFRM_DEV_OFFLOAD_PACKET)
+		/* Make sure that no ARP requests are running in parallel */
+		flush_workqueue(ipsec->wq);
+
 }
 
 static void mlx5e_xfrm_free_state(struct xfrm_state *x)
@@ -683,6 +749,46 @@ static void mlx5e_xfrm_free_state(struct xfrm_state *x)
 	kfree(sa_entry);
 }
 
+static int mlx5e_ipsec_netevent_event(struct notifier_block *nb,
+				      unsigned long event, void *ptr)
+{
+	struct mlx5_accel_esp_xfrm_attrs *attrs;
+	struct mlx5e_ipsec_netevent_data *data;
+	struct mlx5e_ipsec_sa_entry *sa_entry;
+	struct mlx5e_ipsec *ipsec;
+	struct neighbour *n = ptr;
+	struct net_device *netdev;
+	struct xfrm_state *x;
+	unsigned long idx;
+
+	if (event != NETEVENT_NEIGH_UPDATE || !(n->nud_state & NUD_VALID))
+		return NOTIFY_DONE;
+
+	ipsec = container_of(nb, struct mlx5e_ipsec, netevent_nb);
+	xa_for_each_marked(&ipsec->sadb, idx, sa_entry, MLX5E_IPSEC_TUNNEL_SA) {
+		attrs = &sa_entry->attrs;
+
+		if (attrs->family == AF_INET) {
+			if (!neigh_key_eq32(n, &attrs->saddr.a4) &&
+			    !neigh_key_eq32(n, &attrs->daddr.a4))
+				continue;
+		} else {
+			if (!neigh_key_eq128(n, &attrs->saddr.a4) &&
+			    !neigh_key_eq128(n, &attrs->daddr.a4))
+				continue;
+		}
+
+		x = sa_entry->x;
+		netdev = x->xso.real_dev;
+		data = sa_entry->work->data;
+
+		neigh_ha_snapshot(data->addr, n, netdev);
+		queue_work(ipsec->wq, &sa_entry->work->work);
+	}
+
+	return NOTIFY_DONE;
+}
+
 void mlx5e_ipsec_init(struct mlx5e_priv *priv)
 {
 	struct mlx5e_ipsec *ipsec;
@@ -711,6 +817,13 @@ void mlx5e_ipsec_init(struct mlx5e_priv *priv)
 			goto err_aso;
 	}
 
+	if (mlx5_ipsec_device_caps(priv->mdev) & MLX5_IPSEC_CAP_TUNNEL) {
+		ipsec->netevent_nb.notifier_call = mlx5e_ipsec_netevent_event;
+		ret = register_netevent_notifier(&ipsec->netevent_nb);
+		if (ret)
+			goto clear_aso;
+	}
+
 	ret = mlx5e_accel_ipsec_fs_init(ipsec);
 	if (ret)
 		goto err_fs_init;
@@ -721,6 +834,9 @@ void mlx5e_ipsec_init(struct mlx5e_priv *priv)
 	return;
 
 err_fs_init:
+	if (mlx5_ipsec_device_caps(priv->mdev) & MLX5_IPSEC_CAP_TUNNEL)
+		unregister_netevent_notifier(&ipsec->netevent_nb);
+clear_aso:
 	if (mlx5_ipsec_device_caps(priv->mdev) & MLX5_IPSEC_CAP_PACKET_OFFLOAD)
 		mlx5e_ipsec_aso_cleanup(ipsec);
 err_aso:
@@ -739,6 +855,8 @@ void mlx5e_ipsec_cleanup(struct mlx5e_priv *priv)
 		return;
 
 	mlx5e_accel_ipsec_fs_cleanup(ipsec);
+	if (mlx5_ipsec_device_caps(priv->mdev) & MLX5_IPSEC_CAP_TUNNEL)
+		unregister_netevent_notifier(&ipsec->netevent_nb);
 	if (mlx5_ipsec_device_caps(priv->mdev) & MLX5_IPSEC_CAP_PACKET_OFFLOAD)
 		mlx5e_ipsec_aso_cleanup(ipsec);
 	destroy_workqueue(ipsec->wq);

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

@@ -144,6 +144,10 @@ struct mlx5e_ipsec_work {
 	void *data;
 };
 
+struct mlx5e_ipsec_netevent_data {
+	u8 addr[ETH_ALEN];
+};
+
 struct mlx5e_ipsec_dwork {
 	struct delayed_work dwork;
 	struct mlx5e_ipsec_sa_entry *sa_entry;
@@ -169,6 +173,7 @@ struct mlx5e_ipsec {
 	struct mlx5e_ipsec_tx *tx;
 	struct mlx5e_ipsec_aso *aso;
 	struct notifier_block nb;
+	struct notifier_block netevent_nb;
 	struct mlx5_ipsec_fs *roce;
 };