include/net/xdp.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-only */
 /* include/net/xdp.h
  *
  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
  */
 #ifndef __LINUX_NET_XDP_H__
 #define __LINUX_NET_XDP_H__

 #include <linux/skbuff.h> /* skb_shared_info */

 /**
  * DOC: XDP RX-queue information
  *
  * The XDP RX-queue info (xdp_rxq_info) is associated with the driver
  * level RX-ring queues.  It is information that is specific to how
  * the driver have configured a given RX-ring queue.
  *
  * Each xdp_buff frame received in the driver carry a (pointer)
  * reference to this xdp_rxq_info structure.  This provides the XDP
  * data-path read-access to RX-info for both kernel and bpf-side
  * (limited subset).
  *
  * For now, direct access is only safe while running in NAPI/softirq
  * context.  Contents is read-mostly and must not be updated during
  * driver NAPI/softirq poll.
  *
  * The driver usage API is a register and unregister API.
  *
  * The struct is not directly tied to the XDP prog.  A new XDP prog
  * can be attached as long as it doesn't change the underlying
  * RX-ring.  If the RX-ring does change significantly, the NIC driver
  * naturally need to stop the RX-ring before purging and reallocating
  * memory.  In that process the driver MUST call unregistor (which
  * also apply for driver shutdown and unload).  The register API is
  * also mandatory during RX-ring setup.
  */

 enum xdp_mem_type {
 	MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
 	MEM_TYPE_PAGE_ORDER0,     /* Orig XDP full page model */
 	MEM_TYPE_PAGE_POOL,
 	MEM_TYPE_XSK_BUFF_POOL,
 	MEM_TYPE_MAX,
 };

 /* XDP flags for ndo_xdp_xmit */
 #define XDP_XMIT_FLUSH		(1U << 0)	/* doorbell signal consumer */
 #define XDP_XMIT_FLAGS_MASK	XDP_XMIT_FLUSH

 struct xdp_mem_info {
 	u32 type; /* enum xdp_mem_type, but known size type */
 	u32 id;
 };

 struct page_pool;

 struct xdp_rxq_info {
 	struct net_device *dev;
 	u32 queue_index;
 	u32 reg_state;
 	struct xdp_mem_info mem;
 	unsigned int napi_id;
 } ____cacheline_aligned; /* perf critical, avoid false-sharing */

 struct xdp_txq_info {
 	struct net_device *dev;
 };

 struct xdp_buff {
 	void *data;
 	void *data_end;
 	void *data_meta;
 	void *data_hard_start;
 	struct xdp_rxq_info *rxq;
 	struct xdp_txq_info *txq;
 	u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
 };

 static __always_inline void
 xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
 {
 	xdp->frame_sz = frame_sz;
 	xdp->rxq = rxq;
 }

 static __always_inline void
 xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
 		 int headroom, int data_len, const bool meta_valid)
 {
 	unsigned char *data = hard_start + headroom;

 	xdp->data_hard_start = hard_start;
 	xdp->data = data;
 	xdp->data_end = data + data_len;
 	xdp->data_meta = meta_valid ? data : data + 1;
 }

 /* Reserve memory area at end-of data area.
  *
  * This macro reserves tailroom in the XDP buffer by limiting the
  * XDP/BPF data access to data_hard_end.  Notice same area (and size)
  * is used for XDP_PASS, when constructing the SKB via build_skb().
  */
 #define xdp_data_hard_end(xdp)				\
 	((xdp)->data_hard_start + (xdp)->frame_sz -	\
 	 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))

 static inline struct skb_shared_info *
 xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
 {
 	return (struct skb_shared_info *)xdp_data_hard_end(xdp);
 }

 struct xdp_frame {
 	void *data;
 	u16 len;
 	u16 headroom;
 	u32 metasize:8;
 	u32 frame_sz:24;
 	/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
 	 * while mem info is valid on remote CPU.
 	 */
 	struct xdp_mem_info mem;
 	struct net_device *dev_rx; /* used by cpumap */
 };

 #define XDP_BULK_QUEUE_SIZE	16
 struct xdp_frame_bulk {
 	int count;
 	void *xa;
 	void *q[XDP_BULK_QUEUE_SIZE];
 };

 static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
 {
 	/* bq->count will be zero'ed when bq->xa gets updated */
 	bq->xa = NULL;
 }

 static inline struct skb_shared_info *
 xdp_get_shared_info_from_frame(struct xdp_frame *frame)
 {
 	void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);

 	return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
 				SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
 }

 struct xdp_cpumap_stats {
 	unsigned int redirect;
 	unsigned int pass;
 	unsigned int drop;
 };

 /* Clear kernel pointers in xdp_frame */
 static inline void xdp_scrub_frame(struct xdp_frame *frame)
 {
 	frame->data = NULL;
 	frame->dev_rx = NULL;
 }

 /* Avoids inlining WARN macro in fast-path */
 void xdp_warn(const char *msg, const char *func, const int line);
 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)

 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
 					   struct sk_buff *skb,
 					   struct net_device *dev);
 struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
 					 struct net_device *dev);
 int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp);
 struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf);

 static inline
 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
 {
 	xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
 	xdp->data = frame->data;
 	xdp->data_end = frame->data + frame->len;
 	xdp->data_meta = frame->data - frame->metasize;
 	xdp->frame_sz = frame->frame_sz;
 }

 static inline
 int xdp_update_frame_from_buff(struct xdp_buff *xdp,
 			       struct xdp_frame *xdp_frame)
 {
 	int metasize, headroom;

 	/* Assure headroom is available for storing info */
 	headroom = xdp->data - xdp->data_hard_start;
 	metasize = xdp->data - xdp->data_meta;
 	metasize = metasize > 0 ? metasize : 0;
 	if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
 		return -ENOSPC;

 	/* Catch if driver didn't reserve tailroom for skb_shared_info */
 	if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
 		XDP_WARN("Driver BUG: missing reserved tailroom");
 		return -ENOSPC;
 	}

 	xdp_frame->data = xdp->data;
 	xdp_frame->len  = xdp->data_end - xdp->data;
 	xdp_frame->headroom = headroom - sizeof(*xdp_frame);
 	xdp_frame->metasize = metasize;
 	xdp_frame->frame_sz = xdp->frame_sz;

 	return 0;
 }

 /* Convert xdp_buff to xdp_frame */
 static inline
 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
 {
 	struct xdp_frame *xdp_frame;

 	if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
 		return xdp_convert_zc_to_xdp_frame(xdp);

 	/* Store info in top of packet */
 	xdp_frame = xdp->data_hard_start;
 	if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
 		return NULL;

 	/* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
 	xdp_frame->mem = xdp->rxq->mem;

 	return xdp_frame;
 }

 void xdp_return_frame(struct xdp_frame *xdpf);
 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
 void xdp_return_buff(struct xdp_buff *xdp);
 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
 			   struct xdp_frame_bulk *bq);

 /* When sending xdp_frame into the network stack, then there is no
  * return point callback, which is needed to release e.g. DMA-mapping
  * resources with page_pool.  Thus, have explicit function to release
  * frame resources.
  */
 void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
 static inline void xdp_release_frame(struct xdp_frame *xdpf)
 {
 	struct xdp_mem_info *mem = &xdpf->mem;

 	/* Curr only page_pool needs this */
 	if (mem->type == MEM_TYPE_PAGE_POOL)
 		__xdp_release_frame(xdpf->data, mem);
 }

 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
 		     struct net_device *dev, u32 queue_index, unsigned int napi_id);
 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
 			       enum xdp_mem_type type, void *allocator);
 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);

 /* Drivers not supporting XDP metadata can use this helper, which
  * rejects any room expansion for metadata as a result.
  */
 static __always_inline void
 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
 {
 	xdp->data_meta = xdp->data + 1;
 }

 static __always_inline bool
 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
 {
 	return unlikely(xdp->data_meta > xdp->data);
 }

 struct xdp_attachment_info {
 	struct bpf_prog *prog;
 	u32 flags;
 };

 struct netdev_bpf;
 void xdp_attachment_setup(struct xdp_attachment_info *info,
 			  struct netdev_bpf *bpf);

 #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE

 #endif /* __LINUX_NET_XDP_H__ */
	/* SPDX-License-Identifier: GPL-2.0-only */
	/* include/net/xdp.h
	*
	* Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
	*/
	#ifndef __LINUX_NET_XDP_H__
	#define __LINUX_NET_XDP_H__

	#include <linux/skbuff.h> /* skb_shared_info */

	/**
	* DOC: XDP RX-queue information
	*
	* The XDP RX-queue info (xdp_rxq_info) is associated with the driver
	* level RX-ring queues. It is information that is specific to how
	* the driver have configured a given RX-ring queue.
	*
	* Each xdp_buff frame received in the driver carry a (pointer)
	* reference to this xdp_rxq_info structure. This provides the XDP
	* data-path read-access to RX-info for both kernel and bpf-side
	* (limited subset).
	*
	* For now, direct access is only safe while running in NAPI/softirq
	* context. Contents is read-mostly and must not be updated during
	* driver NAPI/softirq poll.
	*
	* The driver usage API is a register and unregister API.
	*
	* The struct is not directly tied to the XDP prog. A new XDP prog
	* can be attached as long as it doesn't change the underlying
	* RX-ring. If the RX-ring does change significantly, the NIC driver
	* naturally need to stop the RX-ring before purging and reallocating
	* memory. In that process the driver MUST call unregistor (which
	* also apply for driver shutdown and unload). The register API is
	* also mandatory during RX-ring setup.
	*/

	enum xdp_mem_type {
	MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
	MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
	MEM_TYPE_PAGE_POOL,
	MEM_TYPE_XSK_BUFF_POOL,
	MEM_TYPE_MAX,
	};

	/* XDP flags for ndo_xdp_xmit */
	#define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */
	#define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH

	struct xdp_mem_info {
	u32 type; /* enum xdp_mem_type, but known size type */
	u32 id;
	};

	struct page_pool;

	struct xdp_rxq_info {
	struct net_device *dev;
	u32 queue_index;
	u32 reg_state;
	struct xdp_mem_info mem;
	unsigned int napi_id;
	} ____cacheline_aligned; /* perf critical, avoid false-sharing */

	struct xdp_txq_info {
	struct net_device *dev;
	};

	struct xdp_buff {
	void *data;
	void *data_end;
	void *data_meta;
	void *data_hard_start;
	struct xdp_rxq_info *rxq;
	struct xdp_txq_info *txq;
	u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
	};

	static __always_inline void
	xdp_init_buff(struct xdp_buff xdp, u32 frame_sz, struct xdp_rxq_info rxq)
	{
	xdp->frame_sz = frame_sz;
	xdp->rxq = rxq;
	}

	static __always_inline void
	xdp_prepare_buff(struct xdp_buff xdp, unsigned char hard_start,
	int headroom, int data_len, const bool meta_valid)
	{
	unsigned char *data = hard_start + headroom;

	xdp->data_hard_start = hard_start;
	xdp->data = data;
	xdp->data_end = data + data_len;
	xdp->data_meta = meta_valid ? data : data + 1;
	}

	/* Reserve memory area at end-of data area.
	*
	* This macro reserves tailroom in the XDP buffer by limiting the
	* XDP/BPF data access to data_hard_end. Notice same area (and size)
	* is used for XDP_PASS, when constructing the SKB via build_skb().
	*/
	#define xdp_data_hard_end(xdp) \
	((xdp)->data_hard_start + (xdp)->frame_sz - \
	SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))

	static inline struct skb_shared_info *
	xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
	{
	return (struct skb_shared_info *)xdp_data_hard_end(xdp);
	}

	struct xdp_frame {
	void *data;
	u16 len;
	u16 headroom;
	u32 metasize:8;
	u32 frame_sz:24;
	/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
	* while mem info is valid on remote CPU.
	*/
	struct xdp_mem_info mem;
	struct net_device dev_rx; / used by cpumap */
	};

	#define XDP_BULK_QUEUE_SIZE 16
	struct xdp_frame_bulk {
	int count;
	void *xa;
	void *q[XDP_BULK_QUEUE_SIZE];
	};

	static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
	{
	/* bq->count will be zero'ed when bq->xa gets updated */
	bq->xa = NULL;
	}

	static inline struct skb_shared_info *
	xdp_get_shared_info_from_frame(struct xdp_frame *frame)
	{
	void data_hard_start = frame->data - frame->headroom - sizeof(frame);

	return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
	SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
	}

	struct xdp_cpumap_stats {
	unsigned int redirect;
	unsigned int pass;
	unsigned int drop;
	};

	/* Clear kernel pointers in xdp_frame */
	static inline void xdp_scrub_frame(struct xdp_frame *frame)
	{
	frame->data = NULL;
	frame->dev_rx = NULL;
	}

	/* Avoids inlining WARN macro in fast-path */
	void xdp_warn(const char msg, const char func, const int line);
	#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)

	struct xdp_frame xdp_convert_zc_to_xdp_frame(struct xdp_buff xdp);
	struct sk_buff __xdp_build_skb_from_frame(struct xdp_frame xdpf,
	struct sk_buff *skb,
	struct net_device *dev);
	struct sk_buff xdp_build_skb_from_frame(struct xdp_frame xdpf,
	struct net_device *dev);
	int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp);
	struct xdp_frame xdpf_clone(struct xdp_frame xdpf);

	static inline
	void xdp_convert_frame_to_buff(struct xdp_frame frame, struct xdp_buff xdp)
	{
	xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
	xdp->data = frame->data;
	xdp->data_end = frame->data + frame->len;
	xdp->data_meta = frame->data - frame->metasize;
	xdp->frame_sz = frame->frame_sz;
	}

	static inline
	int xdp_update_frame_from_buff(struct xdp_buff *xdp,
	struct xdp_frame *xdp_frame)
	{
	int metasize, headroom;

	/* Assure headroom is available for storing info */
	headroom = xdp->data - xdp->data_hard_start;
	metasize = xdp->data - xdp->data_meta;
	metasize = metasize > 0 ? metasize : 0;
	if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
	return -ENOSPC;

	/* Catch if driver didn't reserve tailroom for skb_shared_info */
	if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
	XDP_WARN("Driver BUG: missing reserved tailroom");
	return -ENOSPC;
	}

	xdp_frame->data = xdp->data;
	xdp_frame->len = xdp->data_end - xdp->data;
	xdp_frame->headroom = headroom - sizeof(*xdp_frame);
	xdp_frame->metasize = metasize;
	xdp_frame->frame_sz = xdp->frame_sz;

	return 0;
	}

	/* Convert xdp_buff to xdp_frame */
	static inline
	struct xdp_frame xdp_convert_buff_to_frame(struct xdp_buff xdp)
	{
	struct xdp_frame *xdp_frame;

	if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
	return xdp_convert_zc_to_xdp_frame(xdp);

	/* Store info in top of packet */
	xdp_frame = xdp->data_hard_start;
	if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
	return NULL;

	/* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
	xdp_frame->mem = xdp->rxq->mem;

	return xdp_frame;
	}

	void xdp_return_frame(struct xdp_frame *xdpf);
	void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
	void xdp_return_buff(struct xdp_buff *xdp);
	void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
	void xdp_return_frame_bulk(struct xdp_frame *xdpf,
	struct xdp_frame_bulk *bq);

	/* When sending xdp_frame into the network stack, then there is no
	* return point callback, which is needed to release e.g. DMA-mapping
	* resources with page_pool. Thus, have explicit function to release
	* frame resources.
	*/
	void __xdp_release_frame(void data, struct xdp_mem_info mem);
	static inline void xdp_release_frame(struct xdp_frame *xdpf)
	{
	struct xdp_mem_info *mem = &xdpf->mem;

	/* Curr only page_pool needs this */
	if (mem->type == MEM_TYPE_PAGE_POOL)
	__xdp_release_frame(xdpf->data, mem);
	}

	int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
	struct net_device *dev, u32 queue_index, unsigned int napi_id);
	void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
	void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
	bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
	int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
	enum xdp_mem_type type, void *allocator);
	void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);

	/* Drivers not supporting XDP metadata can use this helper, which
	* rejects any room expansion for metadata as a result.
	*/
	static __always_inline void
	xdp_set_data_meta_invalid(struct xdp_buff *xdp)
	{
	xdp->data_meta = xdp->data + 1;
	}

	static __always_inline bool
	xdp_data_meta_unsupported(const struct xdp_buff *xdp)
	{
	return unlikely(xdp->data_meta > xdp->data);
	}

	struct xdp_attachment_info {
	struct bpf_prog *prog;
	u32 flags;
	};

	struct netdev_bpf;
	void xdp_attachment_setup(struct xdp_attachment_info *info,
	struct netdev_bpf *bpf);

	#define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE

	#endif /* __LINUX_NET_XDP_H__ */