Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2038 insertions, 0 deletions

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
new file mode 100644
index 000000000..0f798bcbe
--- /dev/null
+++ b/drivers/net/veth.c
@@ -0,0 +1,2038 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  drivers/net/veth.c
+ *
+ *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
+ *
+ * Author: Pavel Emelianov <xemul@openvz.org>
+ * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
+ *
+ */
+
+#include <linux/netdevice.h>
+#include <linux/slab.h>
+#include <linux/ethtool.h>
+#include <linux/etherdevice.h>
+#include <linux/u64_stats_sync.h>
+
+#include <net/rtnetlink.h>
+#include <net/dst.h>
+#include <net/xfrm.h>
+#include <net/xdp.h>
+#include <linux/veth.h>
+#include <linux/module.h>
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/ptr_ring.h>
+#include <linux/bpf_trace.h>
+#include <linux/net_tstamp.h>
+#include <net/page_pool/helpers.h>
+
+#define DRV_NAME	"veth"
+#define DRV_VERSION	"1.0"
+
+#define VETH_XDP_FLAG		BIT(0)
+#define VETH_RING_SIZE		256
+#define VETH_XDP_HEADROOM	(XDP_PACKET_HEADROOM + NET_IP_ALIGN)
+
+#define VETH_XDP_TX_BULK_SIZE	16
+#define VETH_XDP_BATCH		16
+
+struct veth_stats {
+	u64	rx_drops;
+	/* xdp */
+	u64	xdp_packets;
+	u64	xdp_bytes;
+	u64	xdp_redirect;
+	u64	xdp_drops;
+	u64	xdp_tx;
+	u64	xdp_tx_err;
+	u64	peer_tq_xdp_xmit;
+	u64	peer_tq_xdp_xmit_err;
+};
+
+struct veth_rq_stats {
+	struct veth_stats	vs;
+	struct u64_stats_sync	syncp;
+};
+
+struct veth_rq {
+	struct napi_struct	xdp_napi;
+	struct napi_struct __rcu *napi; /* points to xdp_napi when the latter is initialized */
+	struct net_device	*dev;
+	struct bpf_prog __rcu	*xdp_prog;
+	struct xdp_mem_info	xdp_mem;
+	struct veth_rq_stats	stats;
+	bool			rx_notify_masked;
+	struct ptr_ring		xdp_ring;
+	struct xdp_rxq_info	xdp_rxq;
+	struct page_pool	*page_pool;
+};
+
+struct veth_priv {
+	struct net_device __rcu	*peer;
+	atomic64_t		dropped;
+	struct bpf_prog		*_xdp_prog;
+	struct veth_rq		*rq;
+	unsigned int		requested_headroom;
+};
+
+struct veth_xdp_tx_bq {
+	struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
+	unsigned int count;
+};
+
+/*
+ * ethtool interface
+ */
+
+struct veth_q_stat_desc {
+	char	desc[ETH_GSTRING_LEN];
+	size_t	offset;
+};
+
+#define VETH_RQ_STAT(m)	offsetof(struct veth_stats, m)
+
+static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
+	{ "xdp_packets",	VETH_RQ_STAT(xdp_packets) },
+	{ "xdp_bytes",		VETH_RQ_STAT(xdp_bytes) },
+	{ "drops",		VETH_RQ_STAT(rx_drops) },
+	{ "xdp_redirect",	VETH_RQ_STAT(xdp_redirect) },
+	{ "xdp_drops",		VETH_RQ_STAT(xdp_drops) },
+	{ "xdp_tx",		VETH_RQ_STAT(xdp_tx) },
+	{ "xdp_tx_errors",	VETH_RQ_STAT(xdp_tx_err) },
+};
+
+#define VETH_RQ_STATS_LEN	ARRAY_SIZE(veth_rq_stats_desc)
+
+static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
+	{ "xdp_xmit",		VETH_RQ_STAT(peer_tq_xdp_xmit) },
+	{ "xdp_xmit_errors",	VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
+};
+
+#define VETH_TQ_STATS_LEN	ARRAY_SIZE(veth_tq_stats_desc)
+
+static struct {
+	const char string[ETH_GSTRING_LEN];
+} ethtool_stats_keys[] = {
+	{ "peer_ifindex" },
+};
+
+struct veth_xdp_buff {
+	struct xdp_buff xdp;
+	struct sk_buff *skb;
+};
+
+static int veth_get_link_ksettings(struct net_device *dev,
+				   struct ethtool_link_ksettings *cmd)
+{
+	cmd->base.speed		= SPEED_10000;
+	cmd->base.duplex	= DUPLEX_FULL;
+	cmd->base.port		= PORT_TP;
+	cmd->base.autoneg	= AUTONEG_DISABLE;
+	return 0;
+}
+
+static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
+{
+	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
+	strscpy(info->version, DRV_VERSION, sizeof(info->version));
+}
+
+static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
+{
+	u8 *p = buf;
+	int i, j;
+
+	switch(stringset) {
+	case ETH_SS_STATS:
+		memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
+		p += sizeof(ethtool_stats_keys);
+		for (i = 0; i < dev->real_num_rx_queues; i++)
+			for (j = 0; j < VETH_RQ_STATS_LEN; j++)
+				ethtool_sprintf(&p, "rx_queue_%u_%.18s",
+						i, veth_rq_stats_desc[j].desc);
+
+		for (i = 0; i < dev->real_num_tx_queues; i++)
+			for (j = 0; j < VETH_TQ_STATS_LEN; j++)
+				ethtool_sprintf(&p, "tx_queue_%u_%.18s",
+						i, veth_tq_stats_desc[j].desc);
+
+		page_pool_ethtool_stats_get_strings(p);
+		break;
+	}
+}
+
+static int veth_get_sset_count(struct net_device *dev, int sset)
+{
+	switch (sset) {
+	case ETH_SS_STATS:
+		return ARRAY_SIZE(ethtool_stats_keys) +
+		       VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
+		       VETH_TQ_STATS_LEN * dev->real_num_tx_queues +
+		       page_pool_ethtool_stats_get_count();
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static void veth_get_page_pool_stats(struct net_device *dev, u64 *data)
+{
+#ifdef CONFIG_PAGE_POOL_STATS
+	struct veth_priv *priv = netdev_priv(dev);
+	struct page_pool_stats pp_stats = {};
+	int i;
+
+	for (i = 0; i < dev->real_num_rx_queues; i++) {
+		if (!priv->rq[i].page_pool)
+			continue;
+		page_pool_get_stats(priv->rq[i].page_pool, &pp_stats);
+	}
+	page_pool_ethtool_stats_get(data, &pp_stats);
+#endif /* CONFIG_PAGE_POOL_STATS */
+}
+
+static void veth_get_ethtool_stats(struct net_device *dev,
+		struct ethtool_stats *stats, u64 *data)
+{
+	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
+	struct net_device *peer = rtnl_dereference(priv->peer);
+	int i, j, idx, pp_idx;
+
+	data[0] = peer ? peer->ifindex : 0;
+	idx = 1;
+	for (i = 0; i < dev->real_num_rx_queues; i++) {
+		const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
+		const void *stats_base = (void *)&rq_stats->vs;
+		unsigned int start;
+		size_t offset;
+
+		do {
+			start = u64_stats_fetch_begin(&rq_stats->syncp);
+			for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
+				offset = veth_rq_stats_desc[j].offset;
+				data[idx + j] = *(u64 *)(stats_base + offset);
+			}
+		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
+		idx += VETH_RQ_STATS_LEN;
+	}
+	pp_idx = idx;
+
+	if (!peer)
+		goto page_pool_stats;
+
+	rcv_priv = netdev_priv(peer);
+	for (i = 0; i < peer->real_num_rx_queues; i++) {
+		const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
+		const void *base = (void *)&rq_stats->vs;
+		unsigned int start, tx_idx = idx;
+		size_t offset;
+
+		tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
+		do {
+			start = u64_stats_fetch_begin(&rq_stats->syncp);
+			for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
+				offset = veth_tq_stats_desc[j].offset;
+				data[tx_idx + j] += *(u64 *)(base + offset);
+			}
+		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
+	}
+	pp_idx = idx + dev->real_num_tx_queues * VETH_TQ_STATS_LEN;
+
+page_pool_stats:
+	veth_get_page_pool_stats(dev, &data[pp_idx]);
+}
+
+static void veth_get_channels(struct net_device *dev,
+			      struct ethtool_channels *channels)
+{
+	channels->tx_count = dev->real_num_tx_queues;
+	channels->rx_count = dev->real_num_rx_queues;
+	channels->max_tx = dev->num_tx_queues;
+	channels->max_rx = dev->num_rx_queues;
+}
+
+static int veth_set_channels(struct net_device *dev,
+			     struct ethtool_channels *ch);
+
+static const struct ethtool_ops veth_ethtool_ops = {
+	.get_drvinfo		= veth_get_drvinfo,
+	.get_link		= ethtool_op_get_link,
+	.get_strings		= veth_get_strings,
+	.get_sset_count		= veth_get_sset_count,
+	.get_ethtool_stats	= veth_get_ethtool_stats,
+	.get_link_ksettings	= veth_get_link_ksettings,
+	.get_ts_info		= ethtool_op_get_ts_info,
+	.get_channels		= veth_get_channels,
+	.set_channels		= veth_set_channels,
+};
+
+/* general routines */
+
+static bool veth_is_xdp_frame(void *ptr)
+{
+	return (unsigned long)ptr & VETH_XDP_FLAG;
+}
+
+static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
+{
+	return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
+}
+
+static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
+{
+	return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
+}
+
+static void veth_ptr_free(void *ptr)
+{
+	if (veth_is_xdp_frame(ptr))
+		xdp_return_frame(veth_ptr_to_xdp(ptr));
+	else
+		kfree_skb(ptr);
+}
+
+static void __veth_xdp_flush(struct veth_rq *rq)
+{
+	/* Write ptr_ring before reading rx_notify_masked */
+	smp_mb();
+	if (!READ_ONCE(rq->rx_notify_masked) &&
+	    napi_schedule_prep(&rq->xdp_napi)) {
+		WRITE_ONCE(rq->rx_notify_masked, true);
+		__napi_schedule(&rq->xdp_napi);
+	}
+}
+
+static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
+{
+	if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
+		dev_kfree_skb_any(skb);
+		return NET_RX_DROP;
+	}
+
+	return NET_RX_SUCCESS;
+}
+
+static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
+			    struct veth_rq *rq, bool xdp)
+{
+	return __dev_forward_skb(dev, skb) ?: xdp ?
+		veth_xdp_rx(rq, skb) :
+		__netif_rx(skb);
+}
+
+/* return true if the specified skb has chances of GRO aggregation
+ * Don't strive for accuracy, but try to avoid GRO overhead in the most
+ * common scenarios.
+ * When XDP is enabled, all traffic is considered eligible, as the xmit
+ * device has TSO off.
+ * When TSO is enabled on the xmit device, we are likely interested only
+ * in UDP aggregation, explicitly check for that if the skb is suspected
+ * - the sock_wfree destructor is used by UDP, ICMP and XDP sockets -
+ * to belong to locally generated UDP traffic.
+ */
+static bool veth_skb_is_eligible_for_gro(const struct net_device *dev,
+					 const struct net_device *rcv,
+					 const struct sk_buff *skb)
+{
+	return !(dev->features & NETIF_F_ALL_TSO) ||
+		(skb->destructor == sock_wfree &&
+		 rcv->features & (NETIF_F_GRO_FRAGLIST | NETIF_F_GRO_UDP_FWD));
+}
+
+static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
+	struct veth_rq *rq = NULL;
+	int ret = NETDEV_TX_OK;
+	struct net_device *rcv;
+	int length = skb->len;
+	bool use_napi = false;
+	int rxq;
+
+	rcu_read_lock();
+	rcv = rcu_dereference(priv->peer);
+	if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
+		kfree_skb(skb);
+		goto drop;
+	}
+
+	rcv_priv = netdev_priv(rcv);
+	rxq = skb_get_queue_mapping(skb);
+	if (rxq < rcv->real_num_rx_queues) {
+		rq = &rcv_priv->rq[rxq];
+
+		/* The napi pointer is available when an XDP program is
+		 * attached or when GRO is enabled
+		 * Don't bother with napi/GRO if the skb can't be aggregated
+		 */
+		use_napi = rcu_access_pointer(rq->napi) &&
+			   veth_skb_is_eligible_for_gro(dev, rcv, skb);
+	}
+
+	skb_tx_timestamp(skb);
+	if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
+		if (!use_napi)
+			dev_sw_netstats_tx_add(dev, 1, length);
+		else
+			__veth_xdp_flush(rq);
+	} else {
+drop:
+		atomic64_inc(&priv->dropped);
+		ret = NET_XMIT_DROP;
+	}
+
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int i;
+
+	result->peer_tq_xdp_xmit_err = 0;
+	result->xdp_packets = 0;
+	result->xdp_tx_err = 0;
+	result->xdp_bytes = 0;
+	result->rx_drops = 0;
+	for (i = 0; i < dev->num_rx_queues; i++) {
+		u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
+		struct veth_rq_stats *stats = &priv->rq[i].stats;
+		unsigned int start;
+
+		do {
+			start = u64_stats_fetch_begin(&stats->syncp);
+			peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
+			xdp_tx_err = stats->vs.xdp_tx_err;
+			packets = stats->vs.xdp_packets;
+			bytes = stats->vs.xdp_bytes;
+			drops = stats->vs.rx_drops;
+		} while (u64_stats_fetch_retry(&stats->syncp, start));
+		result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
+		result->xdp_tx_err += xdp_tx_err;
+		result->xdp_packets += packets;
+		result->xdp_bytes += bytes;
+		result->rx_drops += drops;
+	}
+}
+
+static void veth_get_stats64(struct net_device *dev,
+			     struct rtnl_link_stats64 *tot)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+	struct veth_stats rx;
+
+	tot->tx_dropped = atomic64_read(&priv->dropped);
+	dev_fetch_sw_netstats(tot, dev->tstats);
+
+	veth_stats_rx(&rx, dev);
+	tot->tx_dropped += rx.xdp_tx_err;
+	tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
+	tot->rx_bytes += rx.xdp_bytes;
+	tot->rx_packets += rx.xdp_packets;
+
+	rcu_read_lock();
+	peer = rcu_dereference(priv->peer);
+	if (peer) {
+		struct rtnl_link_stats64 tot_peer = {};
+
+		dev_fetch_sw_netstats(&tot_peer, peer->tstats);
+		tot->rx_bytes += tot_peer.tx_bytes;
+		tot->rx_packets += tot_peer.tx_packets;
+
+		veth_stats_rx(&rx, peer);
+		tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
+		tot->rx_dropped += rx.xdp_tx_err;
+		tot->tx_bytes += rx.xdp_bytes;
+		tot->tx_packets += rx.xdp_packets;
+	}
+	rcu_read_unlock();
+}
+
+/* fake multicast ability */
+static void veth_set_multicast_list(struct net_device *dev)
+{
+}
+
+static int veth_select_rxq(struct net_device *dev)
+{
+	return smp_processor_id() % dev->real_num_rx_queues;
+}
+
+static struct net_device *veth_peer_dev(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+
+	/* Callers must be under RCU read side. */
+	return rcu_dereference(priv->peer);
+}
+
+static int veth_xdp_xmit(struct net_device *dev, int n,
+			 struct xdp_frame **frames,
+			 u32 flags, bool ndo_xmit)
+{
+	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
+	int i, ret = -ENXIO, nxmit = 0;
+	struct net_device *rcv;
+	unsigned int max_len;
+	struct veth_rq *rq;
+
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
+		return -EINVAL;
+
+	rcu_read_lock();
+	rcv = rcu_dereference(priv->peer);
+	if (unlikely(!rcv))
+		goto out;
+
+	rcv_priv = netdev_priv(rcv);
+	rq = &rcv_priv->rq[veth_select_rxq(rcv)];
+	/* The napi pointer is set if NAPI is enabled, which ensures that
+	 * xdp_ring is initialized on receive side and the peer device is up.
+	 */
+	if (!rcu_access_pointer(rq->napi))
+		goto out;
+
+	max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
+
+	spin_lock(&rq->xdp_ring.producer_lock);
+	for (i = 0; i < n; i++) {
+		struct xdp_frame *frame = frames[i];
+		void *ptr = veth_xdp_to_ptr(frame);
+
+		if (unlikely(xdp_get_frame_len(frame) > max_len ||
+			     __ptr_ring_produce(&rq->xdp_ring, ptr)))
+			break;
+		nxmit++;
+	}
+	spin_unlock(&rq->xdp_ring.producer_lock);
+
+	if (flags & XDP_XMIT_FLUSH)
+		__veth_xdp_flush(rq);
+
+	ret = nxmit;
+	if (ndo_xmit) {
+		u64_stats_update_begin(&rq->stats.syncp);
+		rq->stats.vs.peer_tq_xdp_xmit += nxmit;
+		rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
+		u64_stats_update_end(&rq->stats.syncp);
+	}
+
+out:
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
+			     struct xdp_frame **frames, u32 flags)
+{
+	int err;
+
+	err = veth_xdp_xmit(dev, n, frames, flags, true);
+	if (err < 0) {
+		struct veth_priv *priv = netdev_priv(dev);
+
+		atomic64_add(n, &priv->dropped);
+	}
+
+	return err;
+}
+
+static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
+{
+	int sent, i, err = 0, drops;
+
+	sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
+	if (sent < 0) {
+		err = sent;
+		sent = 0;
+	}
+
+	for (i = sent; unlikely(i < bq->count); i++)
+		xdp_return_frame(bq->q[i]);
+
+	drops = bq->count - sent;
+	trace_xdp_bulk_tx(rq->dev, sent, drops, err);
+
+	u64_stats_update_begin(&rq->stats.syncp);
+	rq->stats.vs.xdp_tx += sent;
+	rq->stats.vs.xdp_tx_err += drops;
+	u64_stats_update_end(&rq->stats.syncp);
+
+	bq->count = 0;
+}
+
+static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
+{
+	struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
+	struct net_device *rcv;
+	struct veth_rq *rcv_rq;
+
+	rcu_read_lock();
+	veth_xdp_flush_bq(rq, bq);
+	rcv = rcu_dereference(priv->peer);
+	if (unlikely(!rcv))
+		goto out;
+
+	rcv_priv = netdev_priv(rcv);
+	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
+	/* xdp_ring is initialized on receive side? */
+	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
+		goto out;
+
+	__veth_xdp_flush(rcv_rq);
+out:
+	rcu_read_unlock();
+}
+
+static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
+		       struct veth_xdp_tx_bq *bq)
+{
+	struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
+
+	if (unlikely(!frame))
+		return -EOVERFLOW;
+
+	if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
+		veth_xdp_flush_bq(rq, bq);
+
+	bq->q[bq->count++] = frame;
+
+	return 0;
+}
+
+static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
+					  struct xdp_frame *frame,
+					  struct veth_xdp_tx_bq *bq,
+					  struct veth_stats *stats)
+{
+	struct xdp_frame orig_frame;
+	struct bpf_prog *xdp_prog;
+
+	rcu_read_lock();
+	xdp_prog = rcu_dereference(rq->xdp_prog);
+	if (likely(xdp_prog)) {
+		struct veth_xdp_buff vxbuf;
+		struct xdp_buff *xdp = &vxbuf.xdp;
+		u32 act;
+
+		xdp_convert_frame_to_buff(frame, xdp);
+		xdp->rxq = &rq->xdp_rxq;
+		vxbuf.skb = NULL;
+
+		act = bpf_prog_run_xdp(xdp_prog, xdp);
+
+		switch (act) {
+		case XDP_PASS:
+			if (xdp_update_frame_from_buff(xdp, frame))
+				goto err_xdp;
+			break;
+		case XDP_TX:
+			orig_frame = *frame;
+			xdp->rxq->mem = frame->mem;
+			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
+				trace_xdp_exception(rq->dev, xdp_prog, act);
+				frame = &orig_frame;
+				stats->rx_drops++;
+				goto err_xdp;
+			}
+			stats->xdp_tx++;
+			rcu_read_unlock();
+			goto xdp_xmit;
+		case XDP_REDIRECT:
+			orig_frame = *frame;
+			xdp->rxq->mem = frame->mem;
+			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
+				frame = &orig_frame;
+				stats->rx_drops++;
+				goto err_xdp;
+			}
+			stats->xdp_redirect++;
+			rcu_read_unlock();
+			goto xdp_xmit;
+		default:
+			bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
+			fallthrough;
+		case XDP_ABORTED:
+			trace_xdp_exception(rq->dev, xdp_prog, act);
+			fallthrough;
+		case XDP_DROP:
+			stats->xdp_drops++;
+			goto err_xdp;
+		}
+	}
+	rcu_read_unlock();
+
+	return frame;
+err_xdp:
+	rcu_read_unlock();
+	xdp_return_frame(frame);
+xdp_xmit:
+	return NULL;
+}
+
+/* frames array contains VETH_XDP_BATCH at most */
+static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
+				  int n_xdpf, struct veth_xdp_tx_bq *bq,
+				  struct veth_stats *stats)
+{
+	void *skbs[VETH_XDP_BATCH];
+	int i;
+
+	if (xdp_alloc_skb_bulk(skbs, n_xdpf,
+			       GFP_ATOMIC | __GFP_ZERO) < 0) {
+		for (i = 0; i < n_xdpf; i++)
+			xdp_return_frame(frames[i]);
+		stats->rx_drops += n_xdpf;
+
+		return;
+	}
+
+	for (i = 0; i < n_xdpf; i++) {
+		struct sk_buff *skb = skbs[i];
+
+		skb = __xdp_build_skb_from_frame(frames[i], skb,
+						 rq->dev);
+		if (!skb) {
+			xdp_return_frame(frames[i]);
+			stats->rx_drops++;
+			continue;
+		}
+		napi_gro_receive(&rq->xdp_napi, skb);
+	}
+}
+
+static void veth_xdp_get(struct xdp_buff *xdp)
+{
+	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
+	int i;
+
+	get_page(virt_to_page(xdp->data));
+	if (likely(!xdp_buff_has_frags(xdp)))
+		return;
+
+	for (i = 0; i < sinfo->nr_frags; i++)
+		__skb_frag_ref(&sinfo->frags[i]);
+}
+
+static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
+					struct xdp_buff *xdp,
+					struct sk_buff **pskb)
+{
+	struct sk_buff *skb = *pskb;
+	u32 frame_sz;
+
+	if (skb_shared(skb) || skb_head_is_locked(skb) ||
+	    skb_shinfo(skb)->nr_frags ||
+	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
+		u32 size, len, max_head_size, off;
+		struct sk_buff *nskb;
+		struct page *page;
+		int i, head_off;
+
+		/* We need a private copy of the skb and data buffers since
+		 * the ebpf program can modify it. We segment the original skb
+		 * into order-0 pages without linearize it.
+		 *
+		 * Make sure we have enough space for linear and paged area
+		 */
+		max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
+						  VETH_XDP_HEADROOM);
+		if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
+			goto drop;
+
+		/* Allocate skb head */
+		page = page_pool_dev_alloc_pages(rq->page_pool);
+		if (!page)
+			goto drop;
+
+		nskb = napi_build_skb(page_address(page), PAGE_SIZE);
+		if (!nskb) {
+			page_pool_put_full_page(rq->page_pool, page, true);
+			goto drop;
+		}
+
+		skb_reserve(nskb, VETH_XDP_HEADROOM);
+		skb_copy_header(nskb, skb);
+		skb_mark_for_recycle(nskb);
+
+		size = min_t(u32, skb->len, max_head_size);
+		if (skb_copy_bits(skb, 0, nskb->data, size)) {
+			consume_skb(nskb);
+			goto drop;
+		}
+		skb_put(nskb, size);
+
+		head_off = skb_headroom(nskb) - skb_headroom(skb);
+		skb_headers_offset_update(nskb, head_off);
+
+		/* Allocate paged area of new skb */
+		off = size;
+		len = skb->len - off;
+
+		for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
+			page = page_pool_dev_alloc_pages(rq->page_pool);
+			if (!page) {
+				consume_skb(nskb);
+				goto drop;
+			}
+
+			size = min_t(u32, len, PAGE_SIZE);
+			skb_add_rx_frag(nskb, i, page, 0, size, PAGE_SIZE);
+			if (skb_copy_bits(skb, off, page_address(page),
+					  size)) {
+				consume_skb(nskb);
+				goto drop;
+			}
+
+			len -= size;
+			off += size;
+		}
+
+		consume_skb(skb);
+		skb = nskb;
+	}
+
+	/* SKB "head" area always have tailroom for skb_shared_info */
+	frame_sz = skb_end_pointer(skb) - skb->head;
+	frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
+	xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
+			 skb_headlen(skb), true);
+
+	if (skb_is_nonlinear(skb)) {
+		skb_shinfo(skb)->xdp_frags_size = skb->data_len;
+		xdp_buff_set_frags_flag(xdp);
+	} else {
+		xdp_buff_clear_frags_flag(xdp);
+	}
+	*pskb = skb;
+
+	return 0;
+drop:
+	consume_skb(skb);
+	*pskb = NULL;
+
+	return -ENOMEM;
+}
+
+static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
+					struct sk_buff *skb,
+					struct veth_xdp_tx_bq *bq,
+					struct veth_stats *stats)
+{
+	void *orig_data, *orig_data_end;
+	struct bpf_prog *xdp_prog;
+	struct veth_xdp_buff vxbuf;
+	struct xdp_buff *xdp = &vxbuf.xdp;
+	u32 act, metalen;
+	int off;
+
+	skb_prepare_for_gro(skb);
+
+	rcu_read_lock();
+	xdp_prog = rcu_dereference(rq->xdp_prog);
+	if (unlikely(!xdp_prog)) {
+		rcu_read_unlock();
+		goto out;
+	}
+
+	__skb_push(skb, skb->data - skb_mac_header(skb));
+	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
+		goto drop;
+	vxbuf.skb = skb;
+
+	orig_data = xdp->data;
+	orig_data_end = xdp->data_end;
+
+	act = bpf_prog_run_xdp(xdp_prog, xdp);
+
+	switch (act) {
+	case XDP_PASS:
+		break;
+	case XDP_TX:
+		veth_xdp_get(xdp);
+		consume_skb(skb);
+		xdp->rxq->mem = rq->xdp_mem;
+		if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
+			trace_xdp_exception(rq->dev, xdp_prog, act);
+			stats->rx_drops++;
+			goto err_xdp;
+		}
+		stats->xdp_tx++;
+		rcu_read_unlock();
+		goto xdp_xmit;
+	case XDP_REDIRECT:
+		veth_xdp_get(xdp);
+		consume_skb(skb);
+		xdp->rxq->mem = rq->xdp_mem;
+		if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
+			stats->rx_drops++;
+			goto err_xdp;
+		}
+		stats->xdp_redirect++;
+		rcu_read_unlock();
+		goto xdp_xmit;
+	default:
+		bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
+		fallthrough;
+	case XDP_ABORTED:
+		trace_xdp_exception(rq->dev, xdp_prog, act);
+		fallthrough;
+	case XDP_DROP:
+		stats->xdp_drops++;
+		goto xdp_drop;
+	}
+	rcu_read_unlock();
+
+	/* check if bpf_xdp_adjust_head was used */
+	off = orig_data - xdp->data;
+	if (off > 0)
+		__skb_push(skb, off);
+	else if (off < 0)
+		__skb_pull(skb, -off);
+
+	skb_reset_mac_header(skb);
+
+	/* check if bpf_xdp_adjust_tail was used */
+	off = xdp->data_end - orig_data_end;
+	if (off != 0)
+		__skb_put(skb, off); /* positive on grow, negative on shrink */
+
+	/* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
+	 * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
+	 */
+	if (xdp_buff_has_frags(xdp))
+		skb->data_len = skb_shinfo(skb)->xdp_frags_size;
+	else
+		skb->data_len = 0;
+
+	skb->protocol = eth_type_trans(skb, rq->dev);
+
+	metalen = xdp->data - xdp->data_meta;
+	if (metalen)
+		skb_metadata_set(skb, metalen);
+out:
+	return skb;
+drop:
+	stats->rx_drops++;
+xdp_drop:
+	rcu_read_unlock();
+	kfree_skb(skb);
+	return NULL;
+err_xdp:
+	rcu_read_unlock();
+	xdp_return_buff(xdp);
+xdp_xmit:
+	return NULL;
+}
+
+static int veth_xdp_rcv(struct veth_rq *rq, int budget,
+			struct veth_xdp_tx_bq *bq,
+			struct veth_stats *stats)
+{
+	int i, done = 0, n_xdpf = 0;
+	void *xdpf[VETH_XDP_BATCH];
+
+	for (i = 0; i < budget; i++) {
+		void *ptr = __ptr_ring_consume(&rq->xdp_ring);
+
+		if (!ptr)
+			break;
+
+		if (veth_is_xdp_frame(ptr)) {
+			/* ndo_xdp_xmit */
+			struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
+
+			stats->xdp_bytes += xdp_get_frame_len(frame);
+			frame = veth_xdp_rcv_one(rq, frame, bq, stats);
+			if (frame) {
+				/* XDP_PASS */
+				xdpf[n_xdpf++] = frame;
+				if (n_xdpf == VETH_XDP_BATCH) {
+					veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
+							      bq, stats);
+					n_xdpf = 0;
+				}
+			}
+		} else {
+			/* ndo_start_xmit */
+			struct sk_buff *skb = ptr;
+
+			stats->xdp_bytes += skb->len;
+			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
+			if (skb) {
+				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
+					netif_receive_skb(skb);
+				else
+					napi_gro_receive(&rq->xdp_napi, skb);
+			}
+		}
+		done++;
+	}
+
+	if (n_xdpf)
+		veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
+
+	u64_stats_update_begin(&rq->stats.syncp);
+	rq->stats.vs.xdp_redirect += stats->xdp_redirect;
+	rq->stats.vs.xdp_bytes += stats->xdp_bytes;
+	rq->stats.vs.xdp_drops += stats->xdp_drops;
+	rq->stats.vs.rx_drops += stats->rx_drops;
+	rq->stats.vs.xdp_packets += done;
+	u64_stats_update_end(&rq->stats.syncp);
+
+	return done;
+}
+
+static int veth_poll(struct napi_struct *napi, int budget)
+{
+	struct veth_rq *rq =
+		container_of(napi, struct veth_rq, xdp_napi);
+	struct veth_stats stats = {};
+	struct veth_xdp_tx_bq bq;
+	int done;
+
+	bq.count = 0;
+
+	xdp_set_return_frame_no_direct();
+	done = veth_xdp_rcv(rq, budget, &bq, &stats);
+
+	if (stats.xdp_redirect > 0)
+		xdp_do_flush();
+
+	if (done < budget && napi_complete_done(napi, done)) {
+		/* Write rx_notify_masked before reading ptr_ring */
+		smp_store_mb(rq->rx_notify_masked, false);
+		if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
+			if (napi_schedule_prep(&rq->xdp_napi)) {
+				WRITE_ONCE(rq->rx_notify_masked, true);
+				__napi_schedule(&rq->xdp_napi);
+			}
+		}
+	}
+
+	if (stats.xdp_tx > 0)
+		veth_xdp_flush(rq, &bq);
+	xdp_clear_return_frame_no_direct();
+
+	return done;
+}
+
+static int veth_create_page_pool(struct veth_rq *rq)
+{
+	struct page_pool_params pp_params = {
+		.order = 0,
+		.pool_size = VETH_RING_SIZE,
+		.nid = NUMA_NO_NODE,
+		.dev = &rq->dev->dev,
+	};
+
+	rq->page_pool = page_pool_create(&pp_params);
+	if (IS_ERR(rq->page_pool)) {
+		int err = PTR_ERR(rq->page_pool);
+
+		rq->page_pool = NULL;
+		return err;
+	}
+
+	return 0;
+}
+
+static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int err, i;
+
+	for (i = start; i < end; i++) {
+		err = veth_create_page_pool(&priv->rq[i]);
+		if (err)
+			goto err_page_pool;
+	}
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
+		if (err)
+			goto err_xdp_ring;
+	}
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		napi_enable(&rq->xdp_napi);
+		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
+	}
+
+	return 0;
+
+err_xdp_ring:
+	for (i--; i >= start; i--)
+		ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
+	i = end;
+err_page_pool:
+	for (i--; i >= start; i--) {
+		page_pool_destroy(priv->rq[i].page_pool);
+		priv->rq[i].page_pool = NULL;
+	}
+
+	return err;
+}
+
+static int __veth_napi_enable(struct net_device *dev)
+{
+	return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
+}
+
+static void veth_napi_del_range(struct net_device *dev, int start, int end)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int i;
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		rcu_assign_pointer(priv->rq[i].napi, NULL);
+		napi_disable(&rq->xdp_napi);
+		__netif_napi_del(&rq->xdp_napi);
+	}
+	synchronize_net();
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		rq->rx_notify_masked = false;
+		ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
+	}
+
+	for (i = start; i < end; i++) {
+		page_pool_destroy(priv->rq[i].page_pool);
+		priv->rq[i].page_pool = NULL;
+	}
+}
+
+static void veth_napi_del(struct net_device *dev)
+{
+	veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
+}
+
+static bool veth_gro_requested(const struct net_device *dev)
+{
+	return !!(dev->wanted_features & NETIF_F_GRO);
+}
+
+static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
+				 bool napi_already_on)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int err, i;
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		if (!napi_already_on)
+			netif_napi_add(dev, &rq->xdp_napi, veth_poll);
+		err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
+		if (err < 0)
+			goto err_rxq_reg;
+
+		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
+						 MEM_TYPE_PAGE_SHARED,
+						 NULL);
+		if (err < 0)
+			goto err_reg_mem;
+
+		/* Save original mem info as it can be overwritten */
+		rq->xdp_mem = rq->xdp_rxq.mem;
+	}
+	return 0;
+
+err_reg_mem:
+	xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
+err_rxq_reg:
+	for (i--; i >= start; i--) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		xdp_rxq_info_unreg(&rq->xdp_rxq);
+		if (!napi_already_on)
+			netif_napi_del(&rq->xdp_napi);
+	}
+
+	return err;
+}
+
+static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
+				   bool delete_napi)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int i;
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		rq->xdp_rxq.mem = rq->xdp_mem;
+		xdp_rxq_info_unreg(&rq->xdp_rxq);
+
+		if (delete_napi)
+			netif_napi_del(&rq->xdp_napi);
+	}
+}
+
+static int veth_enable_xdp(struct net_device *dev)
+{
+	bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
+	struct veth_priv *priv = netdev_priv(dev);
+	int err, i;
+
+	if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
+		err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
+		if (err)
+			return err;
+
+		if (!napi_already_on) {
+			err = __veth_napi_enable(dev);
+			if (err) {
+				veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
+				return err;
+			}
+
+			if (!veth_gro_requested(dev)) {
+				/* user-space did not require GRO, but adding XDP
+				 * is supposed to get GRO working
+				 */
+				dev->features |= NETIF_F_GRO;
+				netdev_features_change(dev);
+			}
+		}
+	}
+
+	for (i = 0; i < dev->real_num_rx_queues; i++) {
+		rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
+		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
+	}
+
+	return 0;
+}
+
+static void veth_disable_xdp(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int i;
+
+	for (i = 0; i < dev->real_num_rx_queues; i++)
+		rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
+
+	if (!netif_running(dev) || !veth_gro_requested(dev)) {
+		veth_napi_del(dev);
+
+		/* if user-space did not require GRO, since adding XDP
+		 * enabled it, clear it now
+		 */
+		if (!veth_gro_requested(dev) && netif_running(dev)) {
+			dev->features &= ~NETIF_F_GRO;
+			netdev_features_change(dev);
+		}
+	}
+
+	veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
+}
+
+static int veth_napi_enable_range(struct net_device *dev, int start, int end)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int err, i;
+
+	for (i = start; i < end; i++) {
+		struct veth_rq *rq = &priv->rq[i];
+
+		netif_napi_add(dev, &rq->xdp_napi, veth_poll);
+	}
+
+	err = __veth_napi_enable_range(dev, start, end);
+	if (err) {
+		for (i = start; i < end; i++) {
+			struct veth_rq *rq = &priv->rq[i];
+
+			netif_napi_del(&rq->xdp_napi);
+		}
+		return err;
+	}
+	return err;
+}
+
+static int veth_napi_enable(struct net_device *dev)
+{
+	return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
+}
+
+static void veth_disable_range_safe(struct net_device *dev, int start, int end)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+
+	if (start >= end)
+		return;
+
+	if (priv->_xdp_prog) {
+		veth_napi_del_range(dev, start, end);
+		veth_disable_xdp_range(dev, start, end, false);
+	} else if (veth_gro_requested(dev)) {
+		veth_napi_del_range(dev, start, end);
+	}
+}
+
+static int veth_enable_range_safe(struct net_device *dev, int start, int end)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int err;
+
+	if (start >= end)
+		return 0;
+
+	if (priv->_xdp_prog) {
+		/* these channels are freshly initialized, napi is not on there even
+		 * when GRO is requeste
+		 */
+		err = veth_enable_xdp_range(dev, start, end, false);
+		if (err)
+			return err;
+
+		err = __veth_napi_enable_range(dev, start, end);
+		if (err) {
+			/* on error always delete the newly added napis */
+			veth_disable_xdp_range(dev, start, end, true);
+			return err;
+		}
+	} else if (veth_gro_requested(dev)) {
+		return veth_napi_enable_range(dev, start, end);
+	}
+	return 0;
+}
+
+static void veth_set_xdp_features(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+
+	peer = rtnl_dereference(priv->peer);
+	if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
+		struct veth_priv *priv_peer = netdev_priv(peer);
+		xdp_features_t val = NETDEV_XDP_ACT_BASIC |
+				     NETDEV_XDP_ACT_REDIRECT |
+				     NETDEV_XDP_ACT_RX_SG;
+
+		if (priv_peer->_xdp_prog || veth_gro_requested(peer))
+			val |= NETDEV_XDP_ACT_NDO_XMIT |
+			       NETDEV_XDP_ACT_NDO_XMIT_SG;
+		xdp_set_features_flag(dev, val);
+	} else {
+		xdp_clear_features_flag(dev);
+	}
+}
+
+static int veth_set_channels(struct net_device *dev,
+			     struct ethtool_channels *ch)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	unsigned int old_rx_count, new_rx_count;
+	struct veth_priv *peer_priv;
+	struct net_device *peer;
+	int err;
+
+	/* sanity check. Upper bounds are already enforced by the caller */
+	if (!ch->rx_count || !ch->tx_count)
+		return -EINVAL;
+
+	/* avoid braking XDP, if that is enabled */
+	peer = rtnl_dereference(priv->peer);
+	peer_priv = peer ? netdev_priv(peer) : NULL;
+	if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
+		return -EINVAL;
+
+	if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
+		return -EINVAL;
+
+	old_rx_count = dev->real_num_rx_queues;
+	new_rx_count = ch->rx_count;
+	if (netif_running(dev)) {
+		/* turn device off */
+		netif_carrier_off(dev);
+		if (peer)
+			netif_carrier_off(peer);
+
+		/* try to allocate new resurces, as needed*/
+		err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
+		if (err)
+			goto out;
+	}
+
+	err = netif_set_real_num_rx_queues(dev, ch->rx_count);
+	if (err)
+		goto revert;
+
+	err = netif_set_real_num_tx_queues(dev, ch->tx_count);
+	if (err) {
+		int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
+
+		/* this error condition could happen only if rx and tx change
+		 * in opposite directions (e.g. tx nr raises, rx nr decreases)
+		 * and we can't do anything to fully restore the original
+		 * status
+		 */
+		if (err2)
+			pr_warn("Can't restore rx queues config %d -> %d %d",
+				new_rx_count, old_rx_count, err2);
+		else
+			goto revert;
+	}
+
+out:
+	if (netif_running(dev)) {
+		/* note that we need to swap the arguments WRT the enable part
+		 * to identify the range we have to disable
+		 */
+		veth_disable_range_safe(dev, new_rx_count, old_rx_count);
+		netif_carrier_on(dev);
+		if (peer)
+			netif_carrier_on(peer);
+	}
+
+	/* update XDP supported features */
+	veth_set_xdp_features(dev);
+	if (peer)
+		veth_set_xdp_features(peer);
+
+	return err;
+
+revert:
+	new_rx_count = old_rx_count;
+	old_rx_count = ch->rx_count;
+	goto out;
+}
+
+static int veth_open(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer = rtnl_dereference(priv->peer);
+	int err;
+
+	if (!peer)
+		return -ENOTCONN;
+
+	if (priv->_xdp_prog) {
+		err = veth_enable_xdp(dev);
+		if (err)
+			return err;
+	} else if (veth_gro_requested(dev)) {
+		err = veth_napi_enable(dev);
+		if (err)
+			return err;
+	}
+
+	if (peer->flags & IFF_UP) {
+		netif_carrier_on(dev);
+		netif_carrier_on(peer);
+	}
+
+	veth_set_xdp_features(dev);
+
+	return 0;
+}
+
+static int veth_close(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer = rtnl_dereference(priv->peer);
+
+	netif_carrier_off(dev);
+	if (peer)
+		netif_carrier_off(peer);
+
+	if (priv->_xdp_prog)
+		veth_disable_xdp(dev);
+	else if (veth_gro_requested(dev))
+		veth_napi_del(dev);
+
+	return 0;
+}
+
+static int is_valid_veth_mtu(int mtu)
+{
+	return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
+}
+
+static int veth_alloc_queues(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	int i;
+
+	priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL_ACCOUNT);
+	if (!priv->rq)
+		return -ENOMEM;
+
+	for (i = 0; i < dev->num_rx_queues; i++) {
+		priv->rq[i].dev = dev;
+		u64_stats_init(&priv->rq[i].stats.syncp);
+	}
+
+	return 0;
+}
+
+static void veth_free_queues(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+
+	kfree(priv->rq);
+}
+
+static int veth_dev_init(struct net_device *dev)
+{
+	return veth_alloc_queues(dev);
+}
+
+static void veth_dev_free(struct net_device *dev)
+{
+	veth_free_queues(dev);
+}
+
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void veth_poll_controller(struct net_device *dev)
+{
+	/* veth only receives frames when its peer sends one
+	 * Since it has nothing to do with disabling irqs, we are guaranteed
+	 * never to have pending data when we poll for it so
+	 * there is nothing to do here.
+	 *
+	 * We need this though so netpoll recognizes us as an interface that
+	 * supports polling, which enables bridge devices in virt setups to
+	 * still use netconsole
+	 */
+}
+#endif	/* CONFIG_NET_POLL_CONTROLLER */
+
+static int veth_get_iflink(const struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+	int iflink;
+
+	rcu_read_lock();
+	peer = rcu_dereference(priv->peer);
+	iflink = peer ? peer->ifindex : 0;
+	rcu_read_unlock();
+
+	return iflink;
+}
+
+static netdev_features_t veth_fix_features(struct net_device *dev,
+					   netdev_features_t features)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+
+	peer = rtnl_dereference(priv->peer);
+	if (peer) {
+		struct veth_priv *peer_priv = netdev_priv(peer);
+
+		if (peer_priv->_xdp_prog)
+			features &= ~NETIF_F_GSO_SOFTWARE;
+	}
+	if (priv->_xdp_prog)
+		features |= NETIF_F_GRO;
+
+	return features;
+}
+
+static int veth_set_features(struct net_device *dev,
+			     netdev_features_t features)
+{
+	netdev_features_t changed = features ^ dev->features;
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer;
+	int err;
+
+	if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
+		return 0;
+
+	peer = rtnl_dereference(priv->peer);
+	if (features & NETIF_F_GRO) {
+		err = veth_napi_enable(dev);
+		if (err)
+			return err;
+
+		if (peer)
+			xdp_features_set_redirect_target(peer, true);
+	} else {
+		if (peer)
+			xdp_features_clear_redirect_target(peer);
+		veth_napi_del(dev);
+	}
+	return 0;
+}
+
+static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
+{
+	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
+	struct net_device *peer;
+
+	if (new_hr < 0)
+		new_hr = 0;
+
+	rcu_read_lock();
+	peer = rcu_dereference(priv->peer);
+	if (unlikely(!peer))
+		goto out;
+
+	peer_priv = netdev_priv(peer);
+	priv->requested_headroom = new_hr;
+	new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
+	dev->needed_headroom = new_hr;
+	peer->needed_headroom = new_hr;
+
+out:
+	rcu_read_unlock();
+}
+
+static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
+			struct netlink_ext_ack *extack)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct bpf_prog *old_prog;
+	struct net_device *peer;
+	unsigned int max_mtu;
+	int err;
+
+	old_prog = priv->_xdp_prog;
+	priv->_xdp_prog = prog;
+	peer = rtnl_dereference(priv->peer);
+
+	if (prog) {
+		if (!peer) {
+			NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
+			err = -ENOTCONN;
+			goto err;
+		}
+
+		max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
+			  peer->hard_header_len;
+		/* Allow increasing the max_mtu if the program supports
+		 * XDP fragments.
+		 */
+		if (prog->aux->xdp_has_frags)
+			max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
+
+		if (peer->mtu > max_mtu) {
+			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
+			err = -ERANGE;
+			goto err;
+		}
+
+		if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
+			NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
+			err = -ENOSPC;
+			goto err;
+		}
+
+		if (dev->flags & IFF_UP) {
+			err = veth_enable_xdp(dev);
+			if (err) {
+				NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
+				goto err;
+			}
+		}
+
+		if (!old_prog) {
+			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
+			peer->max_mtu = max_mtu;
+		}
+
+		xdp_features_set_redirect_target(peer, true);
+	}
+
+	if (old_prog) {
+		if (!prog) {
+			if (peer && !veth_gro_requested(dev))
+				xdp_features_clear_redirect_target(peer);
+
+			if (dev->flags & IFF_UP)
+				veth_disable_xdp(dev);
+
+			if (peer) {
+				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
+				peer->max_mtu = ETH_MAX_MTU;
+			}
+		}
+		bpf_prog_put(old_prog);
+	}
+
+	if ((!!old_prog ^ !!prog) && peer)
+		netdev_update_features(peer);
+
+	return 0;
+err:
+	priv->_xdp_prog = old_prog;
+
+	return err;
+}
+
+static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
+{
+	switch (xdp->command) {
+	case XDP_SETUP_PROG:
+		return veth_xdp_set(dev, xdp->prog, xdp->extack);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
+{
+	struct veth_xdp_buff *_ctx = (void *)ctx;
+
+	if (!_ctx->skb)
+		return -ENODATA;
+
+	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
+	return 0;
+}
+
+static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
+			    enum xdp_rss_hash_type *rss_type)
+{
+	struct veth_xdp_buff *_ctx = (void *)ctx;
+	struct sk_buff *skb = _ctx->skb;
+
+	if (!skb)
+		return -ENODATA;
+
+	*hash = skb_get_hash(skb);
+	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;
+
+	return 0;
+}
+
+static const struct net_device_ops veth_netdev_ops = {
+	.ndo_init            = veth_dev_init,
+	.ndo_open            = veth_open,
+	.ndo_stop            = veth_close,
+	.ndo_start_xmit      = veth_xmit,
+	.ndo_get_stats64     = veth_get_stats64,
+	.ndo_set_rx_mode     = veth_set_multicast_list,
+	.ndo_set_mac_address = eth_mac_addr,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	.ndo_poll_controller	= veth_poll_controller,
+#endif
+	.ndo_get_iflink		= veth_get_iflink,
+	.ndo_fix_features	= veth_fix_features,
+	.ndo_set_features	= veth_set_features,
+	.ndo_features_check	= passthru_features_check,
+	.ndo_set_rx_headroom	= veth_set_rx_headroom,
+	.ndo_bpf		= veth_xdp,
+	.ndo_xdp_xmit		= veth_ndo_xdp_xmit,
+	.ndo_get_peer_dev	= veth_peer_dev,
+};
+
+static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
+	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
+	.xmo_rx_hash			= veth_xdp_rx_hash,
+};
+
+#define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
+		       NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
+		       NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
+		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
+		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
+
+static void veth_setup(struct net_device *dev)
+{
+	ether_setup(dev);
+
+	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
+	dev->priv_flags |= IFF_NO_QUEUE;
+	dev->priv_flags |= IFF_PHONY_HEADROOM;
+
+	dev->netdev_ops = &veth_netdev_ops;
+	dev->xdp_metadata_ops = &veth_xdp_metadata_ops;
+	dev->ethtool_ops = &veth_ethtool_ops;
+	dev->features |= NETIF_F_LLTX;
+	dev->features |= VETH_FEATURES;
+	dev->vlan_features = dev->features &
+			     ~(NETIF_F_HW_VLAN_CTAG_TX |
+			       NETIF_F_HW_VLAN_STAG_TX |
+			       NETIF_F_HW_VLAN_CTAG_RX |
+			       NETIF_F_HW_VLAN_STAG_RX);
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = veth_dev_free;
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
+	dev->max_mtu = ETH_MAX_MTU;
+
+	dev->hw_features = VETH_FEATURES;
+	dev->hw_enc_features = VETH_FEATURES;
+	dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
+	netif_set_tso_max_size(dev, GSO_MAX_SIZE);
+}
+
+/*
+ * netlink interface
+ */
+
+static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
+			 struct netlink_ext_ack *extack)
+{
+	if (tb[IFLA_ADDRESS]) {
+		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
+			return -EINVAL;
+		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
+			return -EADDRNOTAVAIL;
+	}
+	if (tb[IFLA_MTU]) {
+		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
+			return -EINVAL;
+	}
+	return 0;
+}
+
+static struct rtnl_link_ops veth_link_ops;
+
+static void veth_disable_gro(struct net_device *dev)
+{
+	dev->features &= ~NETIF_F_GRO;
+	dev->wanted_features &= ~NETIF_F_GRO;
+	netdev_update_features(dev);
+}
+
+static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
+{
+	int err;
+
+	if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
+		err = netif_set_real_num_tx_queues(dev, 1);
+		if (err)
+			return err;
+	}
+	if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
+		err = netif_set_real_num_rx_queues(dev, 1);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int veth_newlink(struct net *src_net, struct net_device *dev,
+			struct nlattr *tb[], struct nlattr *data[],
+			struct netlink_ext_ack *extack)
+{
+	int err;
+	struct net_device *peer;
+	struct veth_priv *priv;
+	char ifname[IFNAMSIZ];
+	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
+	unsigned char name_assign_type;
+	struct ifinfomsg *ifmp;
+	struct net *net;
+
+	/*
+	 * create and register peer first
+	 */
+	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
+		struct nlattr *nla_peer;
+
+		nla_peer = data[VETH_INFO_PEER];
+		ifmp = nla_data(nla_peer);
+		err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack);
+		if (err < 0)
+			return err;
+
+		err = veth_validate(peer_tb, NULL, extack);
+		if (err < 0)
+			return err;
+
+		tbp = peer_tb;
+	} else {
+		ifmp = NULL;
+		tbp = tb;
+	}
+
+	if (ifmp && tbp[IFLA_IFNAME]) {
+		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
+		name_assign_type = NET_NAME_USER;
+	} else {
+		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
+		name_assign_type = NET_NAME_ENUM;
+	}
+
+	net = rtnl_link_get_net(src_net, tbp);
+	if (IS_ERR(net))
+		return PTR_ERR(net);
+
+	peer = rtnl_create_link(net, ifname, name_assign_type,
+				&veth_link_ops, tbp, extack);
+	if (IS_ERR(peer)) {
+		put_net(net);
+		return PTR_ERR(peer);
+	}
+
+	if (!ifmp || !tbp[IFLA_ADDRESS])
+		eth_hw_addr_random(peer);
+
+	if (ifmp && (dev->ifindex != 0))
+		peer->ifindex = ifmp->ifi_index;
+
+	netif_inherit_tso_max(peer, dev);
+
+	err = register_netdevice(peer);
+	put_net(net);
+	net = NULL;
+	if (err < 0)
+		goto err_register_peer;
+
+	/* keep GRO disabled by default to be consistent with the established
+	 * veth behavior
+	 */
+	veth_disable_gro(peer);
+	netif_carrier_off(peer);
+
+	err = rtnl_configure_link(peer, ifmp, 0, NULL);
+	if (err < 0)
+		goto err_configure_peer;
+
+	/*
+	 * register dev last
+	 *
+	 * note, that since we've registered new device the dev's name
+	 * should be re-allocated
+	 */
+
+	if (tb[IFLA_ADDRESS] == NULL)
+		eth_hw_addr_random(dev);
+
+	if (tb[IFLA_IFNAME])
+		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
+	else
+		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
+
+	err = register_netdevice(dev);
+	if (err < 0)
+		goto err_register_dev;
+
+	netif_carrier_off(dev);
+
+	/*
+	 * tie the deviced together
+	 */
+
+	priv = netdev_priv(dev);
+	rcu_assign_pointer(priv->peer, peer);
+	err = veth_init_queues(dev, tb);
+	if (err)
+		goto err_queues;
+
+	priv = netdev_priv(peer);
+	rcu_assign_pointer(priv->peer, dev);
+	err = veth_init_queues(peer, tb);
+	if (err)
+		goto err_queues;
+
+	veth_disable_gro(dev);
+	/* update XDP supported features */
+	veth_set_xdp_features(dev);
+	veth_set_xdp_features(peer);
+
+	return 0;
+
+err_queues:
+	unregister_netdevice(dev);
+err_register_dev:
+	/* nothing to do */
+err_configure_peer:
+	unregister_netdevice(peer);
+	return err;
+
+err_register_peer:
+	free_netdev(peer);
+	return err;
+}
+
+static void veth_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct veth_priv *priv;
+	struct net_device *peer;
+
+	priv = netdev_priv(dev);
+	peer = rtnl_dereference(priv->peer);
+
+	/* Note : dellink() is called from default_device_exit_batch(),
+	 * before a rcu_synchronize() point. The devices are guaranteed
+	 * not being freed before one RCU grace period.
+	 */
+	RCU_INIT_POINTER(priv->peer, NULL);
+	unregister_netdevice_queue(dev, head);
+
+	if (peer) {
+		priv = netdev_priv(peer);
+		RCU_INIT_POINTER(priv->peer, NULL);
+		unregister_netdevice_queue(peer, head);
+	}
+}
+
+static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
+	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
+};
+
+static struct net *veth_get_link_net(const struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+	struct net_device *peer = rtnl_dereference(priv->peer);
+
+	return peer ? dev_net(peer) : dev_net(dev);
+}
+
+static unsigned int veth_get_num_queues(void)
+{
+	/* enforce the same queue limit as rtnl_create_link */
+	int queues = num_possible_cpus();
+
+	if (queues > 4096)
+		queues = 4096;
+	return queues;
+}
+
+static struct rtnl_link_ops veth_link_ops = {
+	.kind		= DRV_NAME,
+	.priv_size	= sizeof(struct veth_priv),
+	.setup		= veth_setup,
+	.validate	= veth_validate,
+	.newlink	= veth_newlink,
+	.dellink	= veth_dellink,
+	.policy		= veth_policy,
+	.maxtype	= VETH_INFO_MAX,
+	.get_link_net	= veth_get_link_net,
+	.get_num_tx_queues	= veth_get_num_queues,
+	.get_num_rx_queues	= veth_get_num_queues,
+};
+
+/*
+ * init/fini
+ */
+
+static __init int veth_init(void)
+{
+	return rtnl_link_register(&veth_link_ops);
+}
+
+static __exit void veth_exit(void)
+{
+	rtnl_link_unregister(&veth_link_ops);
+}
+
+module_init(veth_init);
+module_exit(veth_exit);
+
+MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_RTNL_LINK(DRV_NAME);