Subject: Re: [PATCH net-next v1 06/10] net/mlx5e: Support IPsec TX packet offload in tunnel mode

From: Leon Romanovsky <[email-masked]>
Date: Tue, 18 Apr 2023 09:48:27 +0300

On Mon, Apr 17, 2023 at 03:23:55PM +0200, Simon Horman wrote:
> On Thu, Apr 13, 2023 at 03:29:24PM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <[email-masked]>
> > 
> > Extend mlx5 driver with logic to support IPsec TX packet offload
> > in tunnel mode.
> > 
> > Signed-off-by: Leon Romanovsky <[email-masked]>

<...>

> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c
> > @@ -271,6 +271,18 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
> >  		neigh_ha_snapshot(addr, n, netdev);
> >  		ether_addr_copy(attrs->smac, addr);
> >  		break;
> > +	case XFRM_DEV_OFFLOAD_OUT:
> > +		ether_addr_copy(attrs->smac, addr);
> > +		n = neigh_lookup(&arp_tbl, &attrs->daddr.a4, netdev);
> > +		if (!n) {
> > +			n = neigh_create(&arp_tbl, &attrs->daddr.a4, netdev);
> > +			if (IS_ERR(n))
> > +				return;
> > +			neigh_event_send(n, NULL);
> > +		}
> > +		neigh_ha_snapshot(addr, n, netdev);
> > +		ether_addr_copy(attrs->dmac, addr);
> > +		break;
> 
> I see no problem with the above code.
> However, it does seem very similar to the code for the previous case,
> XFRM_DEV_OFFLOAD_IN. Perhaps this could be refactored somehow.

Yes, it can be refactored to something like this:

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c
index 59b9927ac90f..55b38544422f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c
@@ -252,6 +252,8 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 	struct net_device *netdev;
 	struct neighbour *n;
 	u8 addr[ETH_ALEN];
+	const void *pkey;
+	u8 *dst, *src;
 
 	if (attrs->mode != XFRM_MODE_TUNNEL ||
 	    attrs->type != XFRM_DEV_OFFLOAD_PACKET)
@@ -262,36 +264,31 @@ static void mlx5e_ipsec_init_macs(struct mlx5e_ipsec_sa_entry *sa_entry,
 	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);
-			attrs->drop = true;
-			break;
-		}
-		neigh_ha_snapshot(addr, n, netdev);
-		ether_addr_copy(attrs->smac, addr);
+		src = attrs->dmac;
+		dst = attrs->smac;
+		pkey = &attrs->saddr.a4;
 		break;
 	case XFRM_DEV_OFFLOAD_OUT:
-		ether_addr_copy(attrs->smac, addr);
-		n = neigh_lookup(&arp_tbl, &attrs->daddr.a4, netdev);
-		if (!n) {
-			n = neigh_create(&arp_tbl, &attrs->daddr.a4, netdev);
-			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);
+		src = attrs->smac;
+		dst = attrs->dmac;
+		pkey = &attrs->daddr.a4;
 		break;
 	default:
 		return;
 	}
+
+	ether_addr_copy(src, addr);
+	n = neigh_lookup(&arp_tbl, pkey, netdev);
+	if (!n) {
+		n = neigh_create(&arp_tbl, pkey, netdev);
+		if (IS_ERR(n))
+			return;
+		neigh_event_send(n, NULL);
+		attrs->drop = true;
+	} else {
+		neigh_ha_snapshot(addr, n, netdev);
+		ether_addr_copy(dst, addr);
+	}
 	neigh_release(n);
 }

Thanks