1 files changed, 711 insertions, 0 deletions

diff --git a/net/core/xdp.c b/net/core/xdp.c
new file mode 100644
index 000000000..844c9d99d
--- /dev/null
+++ b/net/core/xdp.c
@@ -0,0 +1,711 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* net/core/xdp.c
+ *
+ * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
+ */
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/netdevice.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/rhashtable.h>
+#include <linux/bug.h>
+#include <net/page_pool.h>
+
+#include <net/xdp.h>
+#include <net/xdp_priv.h> /* struct xdp_mem_allocator */
+#include <trace/events/xdp.h>
+#include <net/xdp_sock_drv.h>
+
+#define REG_STATE_NEW		0x0
+#define REG_STATE_REGISTERED	0x1
+#define REG_STATE_UNREGISTERED	0x2
+#define REG_STATE_UNUSED	0x3
+
+static DEFINE_IDA(mem_id_pool);
+static DEFINE_MUTEX(mem_id_lock);
+#define MEM_ID_MAX 0xFFFE
+#define MEM_ID_MIN 1
+static int mem_id_next = MEM_ID_MIN;
+
+static bool mem_id_init; /* false */
+static struct rhashtable *mem_id_ht;
+
+static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
+{
+	const u32 *k = data;
+	const u32 key = *k;
+
+	BUILD_BUG_ON(sizeof_field(struct xdp_mem_allocator, mem.id)
+		     != sizeof(u32));
+
+	/* Use cyclic increasing ID as direct hash key */
+	return key;
+}
+
+static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
+			  const void *ptr)
+{
+	const struct xdp_mem_allocator *xa = ptr;
+	u32 mem_id = *(u32 *)arg->key;
+
+	return xa->mem.id != mem_id;
+}
+
+static const struct rhashtable_params mem_id_rht_params = {
+	.nelem_hint = 64,
+	.head_offset = offsetof(struct xdp_mem_allocator, node),
+	.key_offset  = offsetof(struct xdp_mem_allocator, mem.id),
+	.key_len = sizeof_field(struct xdp_mem_allocator, mem.id),
+	.max_size = MEM_ID_MAX,
+	.min_size = 8,
+	.automatic_shrinking = true,
+	.hashfn    = xdp_mem_id_hashfn,
+	.obj_cmpfn = xdp_mem_id_cmp,
+};
+
+static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
+{
+	struct xdp_mem_allocator *xa;
+
+	xa = container_of(rcu, struct xdp_mem_allocator, rcu);
+
+	/* Allow this ID to be reused */
+	ida_simple_remove(&mem_id_pool, xa->mem.id);
+
+	kfree(xa);
+}
+
+static void mem_xa_remove(struct xdp_mem_allocator *xa)
+{
+	trace_mem_disconnect(xa);
+
+	if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
+		call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
+}
+
+static void mem_allocator_disconnect(void *allocator)
+{
+	struct xdp_mem_allocator *xa;
+	struct rhashtable_iter iter;
+
+	mutex_lock(&mem_id_lock);
+
+	rhashtable_walk_enter(mem_id_ht, &iter);
+	do {
+		rhashtable_walk_start(&iter);
+
+		while ((xa = rhashtable_walk_next(&iter)) && !IS_ERR(xa)) {
+			if (xa->allocator == allocator)
+				mem_xa_remove(xa);
+		}
+
+		rhashtable_walk_stop(&iter);
+
+	} while (xa == ERR_PTR(-EAGAIN));
+	rhashtable_walk_exit(&iter);
+
+	mutex_unlock(&mem_id_lock);
+}
+
+void xdp_unreg_mem_model(struct xdp_mem_info *mem)
+{
+	struct xdp_mem_allocator *xa;
+	int type = mem->type;
+	int id = mem->id;
+
+	/* Reset mem info to defaults */
+	mem->id = 0;
+	mem->type = 0;
+
+	if (id == 0)
+		return;
+
+	if (type == MEM_TYPE_PAGE_POOL) {
+		rcu_read_lock();
+		xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
+		page_pool_destroy(xa->page_pool);
+		rcu_read_unlock();
+	}
+}
+EXPORT_SYMBOL_GPL(xdp_unreg_mem_model);
+
+void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
+{
+	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
+		WARN(1, "Missing register, driver bug");
+		return;
+	}
+
+	xdp_unreg_mem_model(&xdp_rxq->mem);
+}
+EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
+
+void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
+{
+	/* Simplify driver cleanup code paths, allow unreg "unused" */
+	if (xdp_rxq->reg_state == REG_STATE_UNUSED)
+		return;
+
+	xdp_rxq_info_unreg_mem_model(xdp_rxq);
+
+	xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
+	xdp_rxq->dev = NULL;
+}
+EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
+
+static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
+{
+	memset(xdp_rxq, 0, sizeof(*xdp_rxq));
+}
+
+/* Returns 0 on success, negative on failure */
+int __xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
+		       struct net_device *dev, u32 queue_index,
+		       unsigned int napi_id, u32 frag_size)
+{
+	if (!dev) {
+		WARN(1, "Missing net_device from driver");
+		return -ENODEV;
+	}
+
+	if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
+		WARN(1, "Driver promised not to register this");
+		return -EINVAL;
+	}
+
+	if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
+		WARN(1, "Missing unregister, handled but fix driver");
+		xdp_rxq_info_unreg(xdp_rxq);
+	}
+
+	/* State either UNREGISTERED or NEW */
+	xdp_rxq_info_init(xdp_rxq);
+	xdp_rxq->dev = dev;
+	xdp_rxq->queue_index = queue_index;
+	xdp_rxq->napi_id = napi_id;
+	xdp_rxq->frag_size = frag_size;
+
+	xdp_rxq->reg_state = REG_STATE_REGISTERED;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__xdp_rxq_info_reg);
+
+void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
+{
+	xdp_rxq->reg_state = REG_STATE_UNUSED;
+}
+EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
+
+bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
+{
+	return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
+}
+EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
+
+static int __mem_id_init_hash_table(void)
+{
+	struct rhashtable *rht;
+	int ret;
+
+	if (unlikely(mem_id_init))
+		return 0;
+
+	rht = kzalloc(sizeof(*rht), GFP_KERNEL);
+	if (!rht)
+		return -ENOMEM;
+
+	ret = rhashtable_init(rht, &mem_id_rht_params);
+	if (ret < 0) {
+		kfree(rht);
+		return ret;
+	}
+	mem_id_ht = rht;
+	smp_mb(); /* mutex lock should provide enough pairing */
+	mem_id_init = true;
+
+	return 0;
+}
+
+/* Allocate a cyclic ID that maps to allocator pointer.
+ * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
+ *
+ * Caller must lock mem_id_lock.
+ */
+static int __mem_id_cyclic_get(gfp_t gfp)
+{
+	int retries = 1;
+	int id;
+
+again:
+	id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
+	if (id < 0) {
+		if (id == -ENOSPC) {
+			/* Cyclic allocator, reset next id */
+			if (retries--) {
+				mem_id_next = MEM_ID_MIN;
+				goto again;
+			}
+		}
+		return id; /* errno */
+	}
+	mem_id_next = id + 1;
+
+	return id;
+}
+
+static bool __is_supported_mem_type(enum xdp_mem_type type)
+{
+	if (type == MEM_TYPE_PAGE_POOL)
+		return is_page_pool_compiled_in();
+
+	if (type >= MEM_TYPE_MAX)
+		return false;
+
+	return true;
+}
+
+static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem,
+						     enum xdp_mem_type type,
+						     void *allocator)
+{
+	struct xdp_mem_allocator *xdp_alloc;
+	gfp_t gfp = GFP_KERNEL;
+	int id, errno, ret;
+	void *ptr;
+
+	if (!__is_supported_mem_type(type))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	mem->type = type;
+
+	if (!allocator) {
+		if (type == MEM_TYPE_PAGE_POOL)
+			return ERR_PTR(-EINVAL); /* Setup time check page_pool req */
+		return NULL;
+	}
+
+	/* Delay init of rhashtable to save memory if feature isn't used */
+	if (!mem_id_init) {
+		mutex_lock(&mem_id_lock);
+		ret = __mem_id_init_hash_table();
+		mutex_unlock(&mem_id_lock);
+		if (ret < 0) {
+			WARN_ON(1);
+			return ERR_PTR(ret);
+		}
+	}
+
+	xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
+	if (!xdp_alloc)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&mem_id_lock);
+	id = __mem_id_cyclic_get(gfp);
+	if (id < 0) {
+		errno = id;
+		goto err;
+	}
+	mem->id = id;
+	xdp_alloc->mem = *mem;
+	xdp_alloc->allocator = allocator;
+
+	/* Insert allocator into ID lookup table */
+	ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
+	if (IS_ERR(ptr)) {
+		ida_simple_remove(&mem_id_pool, mem->id);
+		mem->id = 0;
+		errno = PTR_ERR(ptr);
+		goto err;
+	}
+
+	if (type == MEM_TYPE_PAGE_POOL)
+		page_pool_use_xdp_mem(allocator, mem_allocator_disconnect, mem);
+
+	mutex_unlock(&mem_id_lock);
+
+	return xdp_alloc;
+err:
+	mutex_unlock(&mem_id_lock);
+	kfree(xdp_alloc);
+	return ERR_PTR(errno);
+}
+
+int xdp_reg_mem_model(struct xdp_mem_info *mem,
+		      enum xdp_mem_type type, void *allocator)
+{
+	struct xdp_mem_allocator *xdp_alloc;
+
+	xdp_alloc = __xdp_reg_mem_model(mem, type, allocator);
+	if (IS_ERR(xdp_alloc))
+		return PTR_ERR(xdp_alloc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xdp_reg_mem_model);
+
+int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
+			       enum xdp_mem_type type, void *allocator)
+{
+	struct xdp_mem_allocator *xdp_alloc;
+
+	if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
+		WARN(1, "Missing register, driver bug");
+		return -EFAULT;
+	}
+
+	xdp_alloc = __xdp_reg_mem_model(&xdp_rxq->mem, type, allocator);
+	if (IS_ERR(xdp_alloc))
+		return PTR_ERR(xdp_alloc);
+
+	if (trace_mem_connect_enabled() && xdp_alloc)
+		trace_mem_connect(xdp_alloc, xdp_rxq);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
+
+/* XDP RX runs under NAPI protection, and in different delivery error
+ * scenarios (e.g. queue full), it is possible to return the xdp_frame
+ * while still leveraging this protection.  The @napi_direct boolean
+ * is used for those calls sites.  Thus, allowing for faster recycling
+ * of xdp_frames/pages in those cases.
+ */
+void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
+		  struct xdp_buff *xdp)
+{
+	struct page *page;
+
+	switch (mem->type) {
+	case MEM_TYPE_PAGE_POOL:
+		page = virt_to_head_page(data);
+		if (napi_direct && xdp_return_frame_no_direct())
+			napi_direct = false;
+		/* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE)
+		 * as mem->type knows this a page_pool page
+		 */
+		page_pool_put_full_page(page->pp, page, napi_direct);
+		break;
+	case MEM_TYPE_PAGE_SHARED:
+		page_frag_free(data);
+		break;
+	case MEM_TYPE_PAGE_ORDER0:
+		page = virt_to_page(data); /* Assumes order0 page*/
+		put_page(page);
+		break;
+	case MEM_TYPE_XSK_BUFF_POOL:
+		/* NB! Only valid from an xdp_buff! */
+		xsk_buff_free(xdp);
+		break;
+	default:
+		/* Not possible, checked in xdp_rxq_info_reg_mem_model() */
+		WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
+		break;
+	}
+}
+
+void xdp_return_frame(struct xdp_frame *xdpf)
+{
+	struct skb_shared_info *sinfo;
+	int i;
+
+	if (likely(!xdp_frame_has_frags(xdpf)))
+		goto out;
+
+	sinfo = xdp_get_shared_info_from_frame(xdpf);
+	for (i = 0; i < sinfo->nr_frags; i++) {
+		struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+		__xdp_return(page_address(page), &xdpf->mem, false, NULL);
+	}
+out:
+	__xdp_return(xdpf->data, &xdpf->mem, false, NULL);
+}
+EXPORT_SYMBOL_GPL(xdp_return_frame);
+
+void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
+{
+	struct skb_shared_info *sinfo;
+	int i;
+
+	if (likely(!xdp_frame_has_frags(xdpf)))
+		goto out;
+
+	sinfo = xdp_get_shared_info_from_frame(xdpf);
+	for (i = 0; i < sinfo->nr_frags; i++) {
+		struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+		__xdp_return(page_address(page), &xdpf->mem, true, NULL);
+	}
+out:
+	__xdp_return(xdpf->data, &xdpf->mem, true, NULL);
+}
+EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
+
+/* XDP bulk APIs introduce a defer/flush mechanism to return
+ * pages belonging to the same xdp_mem_allocator object
+ * (identified via the mem.id field) in bulk to optimize
+ * I-cache and D-cache.
+ * The bulk queue size is set to 16 to be aligned to how
+ * XDP_REDIRECT bulking works. The bulk is flushed when
+ * it is full or when mem.id changes.
+ * xdp_frame_bulk is usually stored/allocated on the function
+ * call-stack to avoid locking penalties.
+ */
+void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
+{
+	struct xdp_mem_allocator *xa = bq->xa;
+
+	if (unlikely(!xa || !bq->count))
+		return;
+
+	page_pool_put_page_bulk(xa->page_pool, bq->q, bq->count);
+	/* bq->xa is not cleared to save lookup, if mem.id same in next bulk */
+	bq->count = 0;
+}
+EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
+
+/* Must be called with rcu_read_lock held */
+void xdp_return_frame_bulk(struct xdp_frame *xdpf,
+			   struct xdp_frame_bulk *bq)
+{
+	struct xdp_mem_info *mem = &xdpf->mem;
+	struct xdp_mem_allocator *xa;
+
+	if (mem->type != MEM_TYPE_PAGE_POOL) {
+		xdp_return_frame(xdpf);
+		return;
+	}
+
+	xa = bq->xa;
+	if (unlikely(!xa)) {
+		xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
+		bq->count = 0;
+		bq->xa = xa;
+	}
+
+	if (bq->count == XDP_BULK_QUEUE_SIZE)
+		xdp_flush_frame_bulk(bq);
+
+	if (unlikely(mem->id != xa->mem.id)) {
+		xdp_flush_frame_bulk(bq);
+		bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
+	}
+
+	if (unlikely(xdp_frame_has_frags(xdpf))) {
+		struct skb_shared_info *sinfo;
+		int i;
+
+		sinfo = xdp_get_shared_info_from_frame(xdpf);
+		for (i = 0; i < sinfo->nr_frags; i++) {
+			skb_frag_t *frag = &sinfo->frags[i];
+
+			bq->q[bq->count++] = skb_frag_address(frag);
+			if (bq->count == XDP_BULK_QUEUE_SIZE)
+				xdp_flush_frame_bulk(bq);
+		}
+	}
+	bq->q[bq->count++] = xdpf->data;
+}
+EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
+
+void xdp_return_buff(struct xdp_buff *xdp)
+{
+	struct skb_shared_info *sinfo;
+	int i;
+
+	if (likely(!xdp_buff_has_frags(xdp)))
+		goto out;
+
+	sinfo = xdp_get_shared_info_from_buff(xdp);
+	for (i = 0; i < sinfo->nr_frags; i++) {
+		struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+		__xdp_return(page_address(page), &xdp->rxq->mem, true, xdp);
+	}
+out:
+	__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
+}
+EXPORT_SYMBOL_GPL(xdp_return_buff);
+
+/* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
+void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
+{
+	struct xdp_mem_allocator *xa;
+	struct page *page;
+
+	rcu_read_lock();
+	xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
+	page = virt_to_head_page(data);
+	if (xa)
+		page_pool_release_page(xa->page_pool, page);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(__xdp_release_frame);
+
+void xdp_attachment_setup(struct xdp_attachment_info *info,
+			  struct netdev_bpf *bpf)
+{
+	if (info->prog)
+		bpf_prog_put(info->prog);
+	info->prog = bpf->prog;
+	info->flags = bpf->flags;
+}
+EXPORT_SYMBOL_GPL(xdp_attachment_setup);
+
+struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
+{
+	unsigned int metasize, totsize;
+	void *addr, *data_to_copy;
+	struct xdp_frame *xdpf;
+	struct page *page;
+
+	/* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
+	metasize = xdp_data_meta_unsupported(xdp) ? 0 :
+		   xdp->data - xdp->data_meta;
+	totsize = xdp->data_end - xdp->data + metasize;
+
+	if (sizeof(*xdpf) + totsize > PAGE_SIZE)
+		return NULL;
+
+	page = dev_alloc_page();
+	if (!page)
+		return NULL;
+
+	addr = page_to_virt(page);
+	xdpf = addr;
+	memset(xdpf, 0, sizeof(*xdpf));
+
+	addr += sizeof(*xdpf);
+	data_to_copy = metasize ? xdp->data_meta : xdp->data;
+	memcpy(addr, data_to_copy, totsize);
+
+	xdpf->data = addr + metasize;
+	xdpf->len = totsize - metasize;
+	xdpf->headroom = 0;
+	xdpf->metasize = metasize;
+	xdpf->frame_sz = PAGE_SIZE;
+	xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
+
+	xsk_buff_free(xdp);
+	return xdpf;
+}
+EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
+
+/* Used by XDP_WARN macro, to avoid inlining WARN() in fast-path */
+void xdp_warn(const char *msg, const char *func, const int line)
+{
+	WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg);
+};
+EXPORT_SYMBOL_GPL(xdp_warn);
+
+int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp)
+{
+	n_skb = kmem_cache_alloc_bulk(skbuff_head_cache, gfp,
+				      n_skb, skbs);
+	if (unlikely(!n_skb))
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xdp_alloc_skb_bulk);
+
+struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
+					   struct sk_buff *skb,
+					   struct net_device *dev)
+{
+	struct skb_shared_info *sinfo = xdp_get_shared_info_from_frame(xdpf);
+	unsigned int headroom, frame_size;
+	void *hard_start;
+	u8 nr_frags;
+
+	/* xdp frags frame */
+	if (unlikely(xdp_frame_has_frags(xdpf)))
+		nr_frags = sinfo->nr_frags;
+
+	/* Part of headroom was reserved to xdpf */
+	headroom = sizeof(*xdpf) + xdpf->headroom;
+
+	/* Memory size backing xdp_frame data already have reserved
+	 * room for build_skb to place skb_shared_info in tailroom.
+	 */
+	frame_size = xdpf->frame_sz;
+
+	hard_start = xdpf->data - headroom;
+	skb = build_skb_around(skb, hard_start, frame_size);
+	if (unlikely(!skb))
+		return NULL;
+
+	skb_reserve(skb, headroom);
+	__skb_put(skb, xdpf->len);
+	if (xdpf->metasize)
+		skb_metadata_set(skb, xdpf->metasize);
+
+	if (unlikely(xdp_frame_has_frags(xdpf)))
+		xdp_update_skb_shared_info(skb, nr_frags,
+					   sinfo->xdp_frags_size,
+					   nr_frags * xdpf->frame_sz,
+					   xdp_frame_is_frag_pfmemalloc(xdpf));
+
+	/* Essential SKB info: protocol and skb->dev */
+	skb->protocol = eth_type_trans(skb, dev);
+
+	/* Optional SKB info, currently missing:
+	 * - HW checksum info		(skb->ip_summed)
+	 * - HW RX hash			(skb_set_hash)
+	 * - RX ring dev queue index	(skb_record_rx_queue)
+	 */
+
+	/* Until page_pool get SKB return path, release DMA here */
+	xdp_release_frame(xdpf);
+
+	/* Allow SKB to reuse area used by xdp_frame */
+	xdp_scrub_frame(xdpf);
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);
+
+struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
+					 struct net_device *dev)
+{
+	struct sk_buff *skb;
+
+	skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
+	if (unlikely(!skb))
+		return NULL;
+
+	memset(skb, 0, offsetof(struct sk_buff, tail));
+
+	return __xdp_build_skb_from_frame(xdpf, skb, dev);
+}
+EXPORT_SYMBOL_GPL(xdp_build_skb_from_frame);
+
+struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
+{
+	unsigned int headroom, totalsize;
+	struct xdp_frame *nxdpf;
+	struct page *page;
+	void *addr;
+
+	headroom = xdpf->headroom + sizeof(*xdpf);
+	totalsize = headroom + xdpf->len;
+
+	if (unlikely(totalsize > PAGE_SIZE))
+		return NULL;
+	page = dev_alloc_page();
+	if (!page)
+		return NULL;
+	addr = page_to_virt(page);
+
+	memcpy(addr, xdpf, totalsize);
+
+	nxdpf = addr;
+	nxdpf->data = addr + headroom;
+	nxdpf->frame_sz = PAGE_SIZE;
+	nxdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
+	nxdpf->mem.id = 0;
+
+	return nxdpf;
+}