linux/include/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/bitfield.h>
#include <linux/filter.h>
#include <linux/netdevice.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 has configured a given RX-ring queue.
 *
 * Each xdp_buff frame received in the driver carries 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 are 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 needs to stop the RX-ring before purging and reallocating
 * memory.  In that process the driver MUST call unregister (which
 * also applies for driver shutdown and unload).  The register API is
 * also mandatory during RX-ring setup.
 */

enum xdp_mem_type { … };

/* XDP flags for ndo_xdp_xmit */
#define XDP_XMIT_FLUSH …
#define XDP_XMIT_FLAGS_MASK …

struct xdp_mem_info { … };

struct page_pool;

struct xdp_rxq_info { … } ____cacheline_aligned; /* perf critical, avoid false-sharing */

struct xdp_txq_info { … };

enum xdp_buff_flags { … };

struct xdp_buff { … };

static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp)
{ … }

static __always_inline void xdp_buff_set_frags_flag(struct xdp_buff *xdp)
{ … }

static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp)
{ … }

static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp)
{ … }

static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp)
{ … }

static __always_inline void
xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *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)
{ … }

/* 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) …

static inline struct skb_shared_info *
xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
{ … }

static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)
{ … }

struct xdp_frame { … };

static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame)
{ … }

static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame)
{ … }

#define XDP_BULK_QUEUE_SIZE …
struct xdp_frame_bulk { … };

static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
{ … }

static inline struct skb_shared_info *
xdp_get_shared_info_from_frame(struct xdp_frame *frame)
{ … }

struct xdp_cpumap_stats { … };

/* Clear kernel pointers in xdp_frame */
static inline void xdp_scrub_frame(struct xdp_frame *frame)
{ … }

static inline void
xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags,
			   unsigned int size, unsigned int truesize,
			   bool pfmemalloc)
{ … }

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

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)
{ … }

static inline
int xdp_update_frame_from_buff(struct xdp_buff *xdp,
			       struct xdp_frame *xdp_frame)
{ … }

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

void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
		  struct xdp_buff *xdp);
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);

static __always_inline unsigned int xdp_get_frame_len(struct xdp_frame *xdpf)
{ … }

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);
static inline 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);
int xdp_reg_mem_model(struct xdp_mem_info *mem,
		      enum xdp_mem_type type, void *allocator);
void xdp_unreg_mem_model(struct xdp_mem_info *mem);

/* 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)
{ … }

static __always_inline bool
xdp_data_meta_unsupported(const struct xdp_buff *xdp)
{ … }

static inline bool xdp_metalen_invalid(unsigned long metalen)
{ … }

struct xdp_attachment_info { … };

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

#define DEV_MAP_BULK_SIZE …

/* Define the relationship between xdp-rx-metadata kfunc and
 * various other entities:
 * - xdp_rx_metadata enum
 * - netdev netlink enum (Documentation/netlink/specs/netdev.yaml)
 * - kfunc name
 * - xdp_metadata_ops field
 */
#define XDP_METADATA_KFUNC_xxx … \

enum xdp_rx_metadata { … };

enum xdp_rss_hash_type { … };

struct xdp_metadata_ops { … };

#ifdef CONFIG_NET
u32 bpf_xdp_metadata_kfunc_id(int id);
bool bpf_dev_bound_kfunc_id(u32 btf_id);
void xdp_set_features_flag(struct net_device *dev, xdp_features_t val);
void xdp_features_set_redirect_target(struct net_device *dev, bool support_sg);
void xdp_features_clear_redirect_target(struct net_device *dev);
#else
static inline u32 bpf_xdp_metadata_kfunc_id(int id) { return 0; }
static inline bool bpf_dev_bound_kfunc_id(u32 btf_id) { return false; }

static inline void
xdp_set_features_flag(struct net_device *dev, xdp_features_t val)
{
}

static inline void
xdp_features_set_redirect_target(struct net_device *dev, bool support_sg)
{
}

static inline void
xdp_features_clear_redirect_target(struct net_device *dev)
{
}
#endif

static inline void xdp_clear_features_flag(struct net_device *dev)
{ … }

static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
					    struct xdp_buff *xdp)
{ … }
#endif /* __LINUX_NET_XDP_H__ */