path: root/include/linux/bpf.h

/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 */
#ifndef _LINUX_BPF_H
#define _LINUX_BPF_H 1

#include <uapi/linux/bpf.h>

#include <linux/workqueue.h>
#include <linux/file.h>
#include <linux/percpu.h>
#include <linux/err.h>
#include <linux/rbtree_latch.h>
#include <linux/numa.h>
#include <linux/mm_types.h>
#include <linux/wait.h>
#include <linux/u64_stats_sync.h>
#include <linux/refcount.h>
#include <linux/mutex.h>
#include <linux/module.h>

struct bpf_verifier_env;
struct bpf_verifier_log;
struct perf_event;
struct bpf_prog;
struct bpf_prog_aux;
struct bpf_map;
struct sock;
struct seq_file;
struct btf;
struct btf_type;
struct exception_table_entry;

extern struct idr btf_idr;
extern spinlock_t btf_idr_lock;

/* map is generic key/value storage optionally accesible by eBPF programs */
struct bpf_map_ops {
	/* funcs callable from userspace (via syscall) */
	int (*map_alloc_check)(union bpf_attr *attr);
	struct bpf_map *(*map_alloc)(union bpf_attr *attr);
	void (*map_release)(struct bpf_map *map, struct file *map_file);
	void (*map_free)(struct bpf_map *map);
	int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
	void (*map_release_uref)(struct bpf_map *map);
	void *(*map_lookup_elem_sys_only)(struct bpf_map *map, void *key);
	int (*map_lookup_batch)(struct bpf_map *map, const union bpf_attr *attr,
				union bpf_attr __user *uattr);
	int (*map_lookup_and_delete_batch)(struct bpf_map *map,
					   const union bpf_attr *attr,
					   union bpf_attr __user *uattr);
	int (*map_update_batch)(struct bpf_map *map, const union bpf_attr *attr,
				union bpf_attr __user *uattr);
	int (*map_delete_batch)(struct bpf_map *map, const union bpf_attr *attr,
				union bpf_attr __user *uattr);

	/* funcs callable from userspace and from eBPF programs */
	void *(*map_lookup_elem)(struct bpf_map *map, void *key);
	int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
	int (*map_delete_elem)(struct bpf_map *map, void *key);
	int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags);
	int (*map_pop_elem)(struct bpf_map *map, void *value);
	int (*map_peek_elem)(struct bpf_map *map, void *value);

	/* funcs called by prog_array and perf_event_array map */
	void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file,
				int fd);
	void (*map_fd_put_ptr)(void *ptr);
	u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
	u32 (*map_fd_sys_lookup_elem)(void *ptr);
	void (*map_seq_show_elem)(struct bpf_map *map, void *key,
				  struct seq_file *m);
	int (*map_check_btf)(const struct bpf_map *map,
			     const struct btf *btf,
			     const struct btf_type *key_type,
			     const struct btf_type *value_type);

	/* Prog poke tracking helpers. */
	int (*map_poke_track)(struct bpf_map *map, struct bpf_prog_aux *aux);
	void (*map_poke_untrack)(struct bpf_map *map, struct bpf_prog_aux *aux);
	void (*map_poke_run)(struct bpf_map *map, u32 key, struct bpf_prog *old,
			     struct bpf_prog *new);

	/* Direct value access helpers. */
	int (*map_direct_value_addr)(const struct bpf_map *map,
				     u64 *imm, u32 off);
	int (*map_direct_value_meta)(const struct bpf_map *map,
				     u64 imm, u32 *off);
	int (*map_mmap)(struct bpf_map *map, struct vm_area_struct *vma);
};

struct bpf_map_memory {
	u32 pages;
	struct user_struct *user;
};

struct bpf_map {
	/* The first two cachelines with read-mostly members of which some
	 * are also accessed in fast-path (e.g. ops, max_entries).
	 */
	const struct bpf_map_ops *ops ____cacheline_aligned;
	struct bpf_map *inner_map_meta;
#ifdef CONFIG_SECURITY
	void *security;
#endif
	enum bpf_map_type map_type;
	u32 key_size;
	u32 value_size;
	u32 max_entries;
	u32 map_flags;
	int spin_lock_off; /* >=0 valid offset, <0 error */
	u32 id;
	int numa_node;
	u32 btf_key_type_id;
	u32 btf_value_type_id;
	struct btf *btf;
	struct bpf_map_memory memory;
	char name[BPF_OBJ_NAME_LEN];
	u32 btf_vmlinux_value_type_id;
	bool unpriv_array;
	bool frozen; /* write-once; write-protected by freeze_mutex */
	/* 22 bytes hole */

	/* The 3rd and 4th cacheline with misc members to avoid false sharing
	 * particularly with refcounting.
	 */
	atomic64_t refcnt ____cacheline_aligned;
	atomic64_t usercnt;
	struct work_struct work;
	struct mutex freeze_mutex;
	u64 writecnt; /* writable mmap cnt; protected by freeze_mutex */
};

static inline bool map_value_has_spin_lock(const struct bpf_map *map)
{
	return map->spin_lock_off >= 0;
}

static inline void check_and_init_map_lock(struct bpf_map *map, void *dst)
{
	if (likely(!map_value_has_spin_lock(map)))
		return;
	*(struct bpf_spin_lock *)(dst + map->spin_lock_off) =
		(struct bpf_spin_lock){};
}

/* copy everything but bpf_spin_lock */
static inline void copy_map_value(struct bpf_map *map, void *dst, void *src)
{
	if (unlikely(map_value_has_spin_lock(map))) {
		u32 off = map->spin_lock_off;

		memcpy(dst, src, off);
		memcpy(dst + off + sizeof(struct bpf_spin_lock),
		       src + off + sizeof(struct bpf_spin_lock),
		       map->value_size - off - sizeof(struct bpf_spin_lock));
	} else {
		memcpy(dst, src, map->value_size);
	}
}
void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
			   bool lock_src);

struct bpf_offload_dev;
struct bpf_offloaded_map;

struct bpf_map_dev_ops {
	int (*map_get_next_key)(struct bpf_offloaded_map *map,
				void *key, void *next_key);
	int (*map_lookup_elem)(struct bpf_offloaded_map *map,
			       void *key, void *value);
	int (*map_update_elem)(struct bpf_offloaded_map *map,
			       void *key, void *value, u64 flags);
	int (*map_delete_elem)(struct bpf_offloaded_map *map, void *key);
};

struct bpf_offloaded_map {
	struct bpf_map map;
	struct net_device *netdev;
	const struct bpf_map_dev_ops *dev_ops;
	void *dev_priv;
	struct list_head offloads;
};

static inline struct bpf_offloaded_map *map_to_offmap(struct bpf_map *map)
{
	return container_of(map, struct bpf_offloaded_map, map);
}

static inline bool bpf_map_offload_neutral(const struct bpf_map *map)
{
	return map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
}

static inline bool bpf_map_support_seq_show(const struct bpf_map *map)
{
	return (map->btf_value_type_id || map->btf_vmlinux_value_type_id) &&
		map->ops->map_seq_show_elem;
}

int map_check_no_btf(const struct bpf_map *map,
		     const struct btf *btf,
		     const struct btf_type *key_type,
		     const struct btf_type *value_type);

extern const struct bpf_map_ops bpf_map_offload_ops;

/* function argument constraints */
enum bpf_arg_type {
	ARG_DONTCARE = 0,	/* unused argument in helper function */

	/* the following constraints used to prototype
	 * bpf_map_lookup/update/delete_elem() functions
	 */
	ARG_CONST_MAP_PTR,	/* const argument used as pointer to bpf_map */
	ARG_PTR_TO_MAP_KEY,	/* pointer to stack used as map key */
	ARG_PTR_TO_MAP_VALUE,	/* pointer to stack used as map value */
	ARG_PTR_TO_UNINIT_MAP_VALUE,	/* pointer to valid memory used to store a map value */
	ARG_PTR_TO_MAP_VALUE_OR_NULL,	/* pointer to stack used as map value or NULL */

	/* the following constraints used to prototype bpf_memcmp() and other
	 * functions that access data on eBPF program stack
	 */
	ARG_PTR_TO_ME