Add the ability to redirect packets to other devices via XDP_REDIRECT
and to receive redirected frames from other devices via ndo_xdp_xmit.

New functionality:
- XDP_REDIRECT case in e1000_run_xdp() using xdp_do_redirect()
- e1000_xdp_xmit() as the ndo_xdp_xmit callback for receiving
  redirected frames from other devices
- xdp_do_flush() in e1000_finalize_xdp() for REDIR completions
- xdp_features_set/clear_redirect_target() in e1000_xdp_setup()
- NETDEV_XDP_ACT_REDIRECT and NETDEV_XDP_ACT_NDO_XMIT advertised

Assisted-by: claude-opus-4-6
Signed-off-by: Matteo Croce <teknoraver@meta.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 85 +++++++++++++++++++++-
 1 file changed, 81 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index d77f208f00cc..01661e1a74e5 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -41,6 +41,7 @@ char e1000e_driver_name[] = "e1000e";
 #define E1000_XDP_PASS		0
 #define E1000_XDP_CONSUMED	BIT(0)
 #define E1000_XDP_TX		BIT(1)
+#define E1000_XDP_REDIR		BIT(2)
 
 static int debug = -1;
 module_param(debug, int, 0);
@@ -805,6 +806,9 @@ static void e1000_finalize_xdp(struct e1000_adapter *adapter,
 {
 	struct e1000_ring *tx_ring = adapter->tx_ring;
 
+	if (xdp_xmit & E1000_XDP_REDIR)
+		xdp_do_flush();
+
 	if (xdp_xmit & E1000_XDP_TX) {
 		/* Force memory writes to complete before letting h/w
 		 * know there are new descriptors to fetch.
@@ -823,13 +827,14 @@ static void e1000_finalize_xdp(struct e1000_adapter *adapter,
  * @adapter: board private structure
  * @xdp: XDP buffer containing packet data
  *
- * Returns E1000_XDP_PASS, E1000_XDP_TX, or E1000_XDP_CONSUMED
+ * Returns E1000_XDP_PASS, E1000_XDP_TX, E1000_XDP_REDIR, or E1000_XDP_CONSUMED
  **/
 static int e1000_run_xdp(struct e1000_adapter *adapter, struct xdp_buff *xdp)
 {
 	struct bpf_prog *xdp_prog = READ_ONCE(adapter->xdp_prog);
 	struct net_device *netdev = adapter->netdev;
 	int result = E1000_XDP_PASS;
+	int err;
 	u32 act;
 
 	if (!xdp_prog)
@@ -846,6 +851,12 @@ static int e1000_run_xdp(struct e1000_adapter *adapter, struct xdp_buff *xdp)
 		if (result == E1000_XDP_CONSUMED)
 			goto out_failure;
 		break;
+	case XDP_REDIRECT:
+		err = xdp_do_redirect(netdev, xdp, xdp_prog);
+		if (err)
+			goto out_failure;
+		result = E1000_XDP_REDIR;
+		break;
 	default:
 		bpf_warn_invalid_xdp_action(netdev, xdp_prog, act);
 		fallthrough;
@@ -1041,11 +1052,11 @@ static bool e1000_clean_rx_irq_xdp(struct e1000_ring *rx_ring, int *work_done,
 
 			/* page consumed by skb */
 			buffer_info->page = NULL;
-		} else if (xdp_res & E1000_XDP_TX) {
+		} else if (xdp_res & (E1000_XDP_TX | E1000_XDP_REDIR)) {
 			xdp_xmit |= xdp_res;
 			total_rx_bytes += length - crc_len;
 			total_rx_packets++;
-			/* page consumed by XDP TX */
+			/* page consumed by XDP TX/redirect */
 			buffer_info->page = NULL;
 		} else {
 			/* XDP_DROP / XDP_ABORTED - recycle page */
@@ -7812,6 +7823,11 @@ static int e1000_xdp_setup(struct net_device *netdev, struct netdev_bpf *bpf)
 	if (!need_reset)
 		return 0;
 
+	if (prog)
+		xdp_features_set_redirect_target(netdev, true);
+	else
+		xdp_features_clear_redirect_target(netdev);
+
 	if (running) {
 		int err = e1000e_open(netdev);
 
@@ -7837,6 +7853,64 @@ static int e1000_xdp(struct net_device *netdev, struct netdev_bpf *xdp)
 	}
 }
 
+/**
+ * e1000_xdp_xmit - transmit XDP frames from another device
+ * @netdev: network interface device structure
+ * @n: number of frames to transmit
+ * @frames: array of XDP frame pointers
+ * @flags: XDP transmit flags
+ *
+ * This is the ndo_xdp_xmit callback, called when other devices redirect
+ * frames to this device.
+ **/
+static int e1000_xdp_xmit(struct net_device *netdev, int n,
+			  struct xdp_frame **frames, u32 flags)
+{
+	struct e1000_adapter *adapter = netdev_priv(netdev);
+	struct e1000_ring *tx_ring = adapter->tx_ring;
+	struct netdev_queue *nq = netdev_get_tx_queue(netdev, 0);
+	int cpu = smp_processor_id();
+	int nxmit = 0;
+	int i;
+
+	if (unlikely(test_bit(__E1000_DOWN, &adapter->state)))
+		return -ENETDOWN;
+
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+		return -EINVAL;
+
+	if (!adapter->xdp_prog)
+		return -ENXIO;
+
+	__netif_tx_lock(nq, cpu);
+	txq_trans_cond_update(nq);
+
+	for (i = 0; i < n; i++) {
+		int err;
+
+		err = e1000_xdp_xmit_ring(adapter, tx_ring, frames[i]);
+		if (err != E1000_XDP_TX)
+			break;
+		nxmit++;
+	}
+
+	if (unlikely(flags & XDP_XMIT_FLUSH)) {
+		/* Force memory writes to complete before letting h/w
+		 * know there are new descriptors to fetch.
+		 */
+		wmb();
+		if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
+			e1000e_update_tdt_wa(tx_ring,
+					     tx_ring->next_to_use);
+		else
+			writel(tx_ring->next_to_use, tx_ring->tail);
+	}
+
+	__netif_tx_unlock(nq);
+
+	return nxmit;
+}
+
 static const struct net_device_ops e1000e_netdev_ops = {
 	.ndo_open		= e1000e_open,
 	.ndo_stop		= e1000e_close,
@@ -7860,6 +7934,7 @@ static const struct net_device_ops e1000e_netdev_ops = {
 	.ndo_hwtstamp_get	= e1000e_hwtstamp_get,
 	.ndo_hwtstamp_set	= e1000e_hwtstamp_set,
 	.ndo_bpf		= e1000_xdp,
+	.ndo_xdp_xmit		= e1000_xdp_xmit,
 };
 
 /**
@@ -8070,7 +8145,9 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	netdev->max_mtu = adapter->max_hw_frame_size -
 			  (VLAN_ETH_HLEN + ETH_FCS_LEN);
 
-	netdev->xdp_features = NETDEV_XDP_ACT_BASIC;
+	netdev->xdp_features = NETDEV_XDP_ACT_BASIC |
+			       NETDEV_XDP_ACT_REDIRECT |
+			       NETDEV_XDP_ACT_NDO_XMIT;
 
 	if (e1000e_enable_mng_pass_thru(&adapter->hw))
 		adapter->flags |= FLAG_MNG_PT_ENABLED;
-- 
2.53.0

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> Of Matteo Croce
> Sent: Monday, March 23, 2026 7:28 PM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
> <andrew+netdev@lunn.ch>; David S. Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>; Alexei Starovoitov <ast@kernel.org>; Daniel
> Borkmann <daniel@iogearbox.net>; Jesper Dangaard Brouer
> <hawk@kernel.org>; John Fastabend <john.fastabend@gmail.com>; Mohsin
> Bashir <mohsin.bashr@gmail.com>
> Cc: netdev@vger.kernel.org; bpf@vger.kernel.org; intel-wired-
> lan@lists.osuosl.org; linux-kernel@vger.kernel.org
> Subject: [Intel-wired-lan] [PATCH net-next v4 2/2] e1000e: add
> XDP_REDIRECT support
> 
> Add the ability to redirect packets to other devices via XDP_REDIRECT
> and to receive redirected frames from other devices via ndo_xdp_xmit.
> 
> New functionality:
> - XDP_REDIRECT case in e1000_run_xdp() using xdp_do_redirect()
> - e1000_xdp_xmit() as the ndo_xdp_xmit callback for receiving
>   redirected frames from other devices
> - xdp_do_flush() in e1000_finalize_xdp() for REDIR completions
> - xdp_features_set/clear_redirect_target() in e1000_xdp_setup()
> - NETDEV_XDP_ACT_REDIRECT and NETDEV_XDP_ACT_NDO_XMIT advertised
> 
> Assisted-by: claude-opus-4-6
> Signed-off-by: Matteo Croce <teknoraver@meta.com>
> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c | 85
> +++++++++++++++++++++-
>  1 file changed, 81 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
> b/drivers/net/ethernet/intel/e1000e/netdev.c
> index d77f208f00cc..01661e1a74e5 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -41,6 +41,7 @@ char e1000e_driver_name[] = "e1000e";
>  #define E1000_XDP_PASS		0
>  #define E1000_XDP_CONSUMED	BIT(0)
>  #define E1000_XDP_TX		BIT(1)

...

> 
> +/**
> + * e1000_xdp_xmit - transmit XDP frames from another device
> + * @netdev: network interface device structure
> + * @n: number of frames to transmit
> + * @frames: array of XDP frame pointers
> + * @flags: XDP transmit flags
> + *
> + * This is the ndo_xdp_xmit callback, called when other devices
> +redirect
> + * frames to this device.
> + **/
> +static int e1000_xdp_xmit(struct net_device *netdev, int n,
> +			  struct xdp_frame **frames, u32 flags) {
> +	struct e1000_adapter *adapter = netdev_priv(netdev);
> +	struct e1000_ring *tx_ring = adapter->tx_ring;
> +	struct netdev_queue *nq = netdev_get_tx_queue(netdev, 0);
> +	int cpu = smp_processor_id();
> +	int nxmit = 0;
> +	int i;
> +
> +	if (unlikely(test_bit(__E1000_DOWN, &adapter->state)))
> +		return -ENETDOWN;
> +
> +	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
> +		return -EINVAL;
> +
> +	if (!adapter->xdp_prog)
> +		return -ENXIO;
> +
> +	__netif_tx_lock(nq, cpu);
> +	txq_trans_cond_update(nq);
> +
> +	for (i = 0; i < n; i++) {
> +		int err;
> +
> +		err = e1000_xdp_xmit_ring(adapter, tx_ring, frames[i]);
> +		if (err != E1000_XDP_TX)
> +			break;
On first failure, we break out of the loop. frames[i] through frames[n-1] are silently abandoned.
It should be no memleaks I hope, but silent packets drop is nasty!

> +		nxmit++;
> +	}
> +
> +	if (unlikely(flags & XDP_XMIT_FLUSH)) {
> +		/* Force memory writes to complete before letting h/w
> +		 * know there are new descriptors to fetch.
> +		 */
> +		wmb();
> +		if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
> +			e1000e_update_tdt_wa(tx_ring,
> +					     tx_ring->next_to_use);
> +		else
> +			writel(tx_ring->next_to_use, tx_ring->tail);
> +	}
> +
> +	__netif_tx_unlock(nq);
> +
> +	return nxmit;
> +}
> +

...

> --
> 2.53.0

Il giorno mar 24 mar 2026 alle ore 09:48 Loktionov, Aleksandr
<aleksandr.loktionov@intel.com> ha scritto:
>
>
>
> > -----Original Message-----
> > From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> > Of Matteo Croce
> > Sent: Monday, March 23, 2026 7:28 PM
> > To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> > Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
> > <andrew+netdev@lunn.ch>; David S. Miller <davem@davemloft.net>; Eric
> > Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> > Abeni <pabeni@redhat.com>; Alexei Starovoitov <ast@kernel.org>; Daniel
> > Borkmann <daniel@iogearbox.net>; Jesper Dangaard Brouer
> > <hawk@kernel.org>; John Fastabend <john.fastabend@gmail.com>; Mohsin
> > Bashir <mohsin.bashr@gmail.com>
> > Cc: netdev@vger.kernel.org; bpf@vger.kernel.org; intel-wired-
> > lan@lists.osuosl.org; linux-kernel@vger.kernel.org
> > Subject: [Intel-wired-lan] [PATCH net-next v4 2/2] e1000e: add
> > XDP_REDIRECT support
> >
> > Add the ability to redirect packets to other devices via XDP_REDIRECT
> > and to receive redirected frames from other devices via ndo_xdp_xmit.
> >
> > New functionality:
> > - XDP_REDIRECT case in e1000_run_xdp() using xdp_do_redirect()
> > - e1000_xdp_xmit() as the ndo_xdp_xmit callback for receiving
> >   redirected frames from other devices
> > - xdp_do_flush() in e1000_finalize_xdp() for REDIR completions
> > - xdp_features_set/clear_redirect_target() in e1000_xdp_setup()
> > - NETDEV_XDP_ACT_REDIRECT and NETDEV_XDP_ACT_NDO_XMIT advertised
> >
> > Assisted-by: claude-opus-4-6
> > Signed-off-by: Matteo Croce <teknoraver@meta.com>
> > ---
> >  drivers/net/ethernet/intel/e1000e/netdev.c | 85
> > +++++++++++++++++++++-
> >  1 file changed, 81 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
> > b/drivers/net/ethernet/intel/e1000e/netdev.c
> > index d77f208f00cc..01661e1a74e5 100644
> > --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> > +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> > @@ -41,6 +41,7 @@ char e1000e_driver_name[] = "e1000e";
> >  #define E1000_XDP_PASS               0
> >  #define E1000_XDP_CONSUMED   BIT(0)
> >  #define E1000_XDP_TX         BIT(1)
>
> ...
>
> >
> > +/**
> > + * e1000_xdp_xmit - transmit XDP frames from another device
> > + * @netdev: network interface device structure
> > + * @n: number of frames to transmit
> > + * @frames: array of XDP frame pointers
> > + * @flags: XDP transmit flags
> > + *
> > + * This is the ndo_xdp_xmit callback, called when other devices
> > +redirect
> > + * frames to this device.
> > + **/
> > +static int e1000_xdp_xmit(struct net_device *netdev, int n,
> > +                       struct xdp_frame **frames, u32 flags) {
> > +     struct e1000_adapter *adapter = netdev_priv(netdev);
> > +     struct e1000_ring *tx_ring = adapter->tx_ring;
> > +     struct netdev_queue *nq = netdev_get_tx_queue(netdev, 0);
> > +     int cpu = smp_processor_id();
> > +     int nxmit = 0;
> > +     int i;
> > +
> > +     if (unlikely(test_bit(__E1000_DOWN, &adapter->state)))
> > +             return -ENETDOWN;
> > +
> > +     if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
> > +             return -EINVAL;
> > +
> > +     if (!adapter->xdp_prog)
> > +             return -ENXIO;
> > +
> > +     __netif_tx_lock(nq, cpu);
> > +     txq_trans_cond_update(nq);
> > +
> > +     for (i = 0; i < n; i++) {
> > +             int err;
> > +
> > +             err = e1000_xdp_xmit_ring(adapter, tx_ring, frames[i]);
> > +             if (err != E1000_XDP_TX)
> > +                     break;
> On first failure, we break out of the loop. frames[i] through frames[n-1] are silently abandoned.
> It should be no memleaks I hope, but silent packets drop is nasty!
>

I wanted to be consistent with other similar drivers, this i what igb
does in igb_main.c:

for (i = 0; i < n; i++) {
        struct xdp_frame *xdpf = frames[i];
        int err;

        err = igb_xmit_xdp_ring(adapter, tx_ring, xdpf);
        if (err != IGB_XDP_TX)
                break;
        nxmit++;
}

Regards,
-- 
Matteo Croce

perl -e 'for($t=0;;$t++){print chr($t*($t>>8|$t>>13)&255)}' |aplay