/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#ifndef _LINUX_BPF_H
#define _LINUX_BPF_H 1

#include <uapi/linux/bpf.h>
#include <linux/workqueue.h>
#include <linux/file.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/err.h>

struct perf_event;
struct bpf_map;

/* 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);

        /* 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);

        /* 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);
};

struct bpf_map {
        /* 1st cacheline 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;
        u32 pages;
        u32 id;
        int numa_node;
        bool unpriv_array;
        /* 7 bytes hole */

        /* 2nd cacheline with misc members to avoid false sharing
         * particularly with refcounting.
         */
        struct user_struct *user ____cacheline_aligned;
        atomic_t refcnt;
        atomic_t usercnt;
        struct work_struct work;
        char name[BPF_OBJ_NAME_LEN];
};

/* 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 */

        /* the following constraints used to prototype bpf_memcmp() and other
         * functions that access data on eBPF program stack
         */
        ARG_PTR_TO_MEM,         /* pointer to valid memory (stack, packet, map value) */
        ARG_PTR_TO_MEM_OR_NULL, /* pointer to valid memory or NULL */
        ARG_PTR_TO_UNINIT_MEM,  /* pointer to memory does not need to be initialized,
                                 * helper function must fill all bytes or clear
                                 * them in error case.
                                 */

        ARG_CONST_SIZE,         /* number of bytes accessed from memory */
        ARG_CONST_SIZE_OR_ZERO, /* number of bytes accessed from memory or 0 */

        ARG_PTR_TO_CTX,         /* pointer to context */
        ARG_ANYTHING,           /* any (initialized) argument is ok */
};

/* type of values returned from helper functions */
enum bpf_return_type {
        RET_INTEGER,                    /* function returns integer */
        RET_VOID,                       /* function doesn't return anything */
        RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
};

/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
 * instructions after verifying
 */
struct bpf_func_proto {
        u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
        bool gpl_only;
        bool pkt_access;
        enum bpf_return_type ret_type;
        enum bpf_arg_type arg1_type;
        enum bpf_arg_type arg2_type;
        enum bpf_arg_type arg3_type;
        enum bpf_arg_type arg4_type;
        enum bpf_arg_type arg5_type;
};

/* bpf_context is intentionally undefined structure. Pointer to bpf_context is
 * the first argument to eBPF programs.
 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
 */
struct bpf_context;

enum bpf_access_type {
        BPF_READ = 1,
        BPF_WRITE = 2
};

/* types of values stored in eBPF registers */
/* Pointer types represent:
 * pointer
 * pointer + imm
 * pointer + (u16) var
 * pointer + (u16) var + imm
 * if (range > 0) then [ptr, ptr + range - off) is safe to access
 * if (id > 0) means that some 'var' was added
 * if (off > 0) means that 'imm' was added
 */
enum bpf_reg_type {
        NOT_INIT = 0,            /* nothing was written into register */
        SCALAR_VALUE,            /* reg doesn't contain a valid pointer */
        PTR_TO_CTX,              /* reg points to bpf_context */
        CONST_PTR_TO_MAP,        /* reg points to struct bpf_map */
        PTR_TO_MAP_VALUE,        /* reg points to map element value */
        PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
        PTR_TO_STACK,            /* reg == frame_pointer + offset */
        PTR_TO_PACKET_META,      /* skb->data - meta_len */
        PTR_TO_PACKET,           /* reg points to skb->data */
        PTR_TO_PACKET_END,       /* skb->data + headlen */
};

struct bpf_prog;

/* The information passed from prog-specific *_is_valid_access
 * back to the verifier.
 */
struct bpf_insn_access_aux {
        enum bpf_reg_type reg_type;
        int ctx_field_size;
};

static inline void
bpf_ctx_record_field_size(struct bpf_insn_access_aux *aux, u32 size)
{
        aux->ctx_field_size = size;
}

struct bpf_prog_ops {
        int (*test_run)(struct bpf_prog *prog, const union bpf_attr *kattr,
                        union bpf_attr __user *uattr);
};

struct bpf_verifier_ops {
        /* return eBPF function prototype for verification */
        const struct bpf_func_proto *
        (*get_func_proto)(enum bpf_func_id func_id,
                          const struct bpf_prog *prog);

        /* return true if 'size' wide access at offset 'off' within bpf_context
         * with 'type' (read or write) is allowed
         */
        bool (*is_valid_access)(int off, int size, enum bpf_access_type type,
                                const struct bpf_prog *prog,
                                struct bpf_insn_access_aux *info);
        int (*gen_prologue)(struct bpf_insn *insn, bool direct_write,
                            const struct bpf_prog *prog);
        u32 (*convert_ctx_access)(enum bpf_access_type type,
                                  const struct bpf_insn *src,
                                  struct bpf_insn *dst,
                                  struct bpf_prog *prog, u32 *target_size);
};

struct bpf_prog_aux {
        atomic_t refcnt;
        u32 used_map_cnt;
        u32 id;
        u32 func_cnt;
        struct bpf_prog **func;
        void *jit_data; /* JIT specific data. arch dependent */
        u32 max_ctx_offset;
        u32 stack_depth;
        const struct bpf_prog_ops *ops;
        struct bpf_map **used_maps;
        struct bpf_prog *prog;
        struct user_struct *user;
        u64 load_time; /* ns since boottime */
        char name[BPF_OBJ_NAME_LEN];
#ifdef CONFIG_SECURITY
        void *security;
#endif
        union {
                struct work_struct work;
                struct rcu_head rcu;
        };
};

struct bpf_array {
        struct bpf_map map;
        u32 elem_size;
        u32 index_mask;
        /* 'ownership' of prog_array is claimed by the first program that
         * is going to use this map or by the first program which FD is stored
         * in the map to make sure that all callers and callees have the same
         * prog_type and JITed flag
         */
        enum bpf_prog_type owner_prog_type;
        bool owner_jited;
        union {
                char value[0] __aligned(8);
                void *ptrs[0] __aligned(8);
                void __percpu *pptrs[0] __aligned(8);
        };
};

#define MAX_TAIL_CALL_CNT 32

struct bpf_event_entry {
        struct perf_event *event;
        struct file *perf_file;
        struct file *map_file;
        struct rcu_head rcu;
};

bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
int bpf_prog_calc_tag(struct bpf_prog *fp);

const struct bpf_func_proto *bpf_get_trace_printk_proto(void);

typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src,
                                        unsigned long off, unsigned long len);

u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
                     void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy);

int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
                          union bpf_attr __user *uattr);

/* an array of programs to be executed under rcu_lock.
 *
 * Typical usage:
 * ret = BPF_PROG_RUN_ARRAY(&bpf_prog_array, ctx, BPF_PROG_RUN);
 *
 * the structure returned by bpf_prog_array_alloc() should be populated
 * with program pointers and the last pointer must be NULL.
 * The user has to keep refcnt on the program and make sure the program
 * is removed from the array before bpf_prog_put().
 * The 'struct bpf_prog_array *' should only be replaced with xchg()
 * since other cpus are walking the array of pointers in parallel.
 */
struct bpf_prog_array {
        struct rcu_head rcu;
        struct bpf_prog *progs[0];
};

struct bpf_prog_array __rcu *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags);
void bpf_prog_array_free(struct bpf_prog_array __rcu *progs);
int bpf_prog_array_length(struct bpf_prog_array __rcu *progs);
int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
                                __u32 __user *prog_ids, u32 cnt);

void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,
                                struct bpf_prog *old_prog);
int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
                             u32 *prog_ids, u32 request_cnt,
                             u32 *prog_cnt);
int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
                        struct bpf_prog *exclude_prog,
                        struct bpf_prog *include_prog,
                        struct bpf_prog_array **new_array);

#define __BPF_PROG_RUN_ARRAY(array, ctx, func, check_non_null)  \
        ({                                              \
                struct bpf_prog **_prog, *__prog;       \
                struct bpf_prog_array *_array;          \
                u32 _ret = 1;                           \
                rcu_read_lock();                        \
                _array = rcu_dereference(array);        \
                if (unlikely(check_non_null && !_array))\
                        goto _out;                      \
                _prog = _array->progs;                  \
                while ((__prog = READ_ONCE(*_prog))) {  \
                        _ret &= func(__prog, ctx);      \
                        _prog++;                        \
                }                                       \
_out:                                                   \
                rcu_read_unlock();                      \
                _ret;                                   \
         })

#define BPF_PROG_RUN_ARRAY(array, ctx, func)            \
        __BPF_PROG_RUN_ARRAY(array, ctx, func, false)

#define BPF_PROG_RUN_ARRAY_CHECK(array, ctx, func)      \
        __BPF_PROG_RUN_ARRAY(array, ctx, func, true)

#ifdef CONFIG_BPF_SYSCALL
DECLARE_PER_CPU(int, bpf_prog_active);

extern const struct file_operations bpf_map_fops;
extern const struct file_operations bpf_prog_fops;

#define BPF_PROG_TYPE(_id, _name) \
        extern const struct bpf_prog_ops _name ## _prog_ops; \
        extern const struct bpf_verifier_ops _name ## _verifier_ops;
#define BPF_MAP_TYPE(_id, _ops) \
        extern const struct bpf_map_ops _ops;
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE

struct bpf_prog *bpf_prog_get(u32 ufd);
struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
struct bpf_prog * __must_check bpf_prog_inc_not_zero(struct bpf_prog *prog);
void bpf_prog_put(struct bpf_prog *prog);
int __bpf_prog_charge(struct user_struct *user, u32 pages);
void __bpf_prog_uncharge(struct user_struct *user, u32 pages);

struct bpf_map *bpf_map_get(u32 ufd);
struct bpf_map *__bpf_map_get(struct fd f);
struct bpf_map *bpf_map_get_with_uref(u32 ufd);
struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref);
void bpf_map_put_with_uref(struct bpf_map *map);
void bpf_map_put(struct bpf_map *map);
int bpf_map_precharge_memlock(u32 pages);
void *bpf_map_area_alloc(size_t size, int numa_node);
void bpf_map_area_free(void *base);
void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr);

extern int sysctl_unprivileged_bpf_disabled;

int bpf_map_new_fd(struct bpf_map *map, int flags);
int bpf_prog_new_fd(struct bpf_prog *prog);

int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
int bpf_obj_get_user(const char __user *pathname, int flags);

int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
                           u64 flags);
int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
                            u64 flags);

int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);

int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
                                 void *key, void *value, u64 map_flags);
int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
void bpf_fd_array_map_clear(struct bpf_map *map);
int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
                                void *key, void *value, u64 map_flags);
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);

int bpf_get_file_flag(int flags);

/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
 * forced to use 'long' read/writes to try to atomically copy long counters.
 * Best-effort only.  No barriers here, since it _will_ race with concurrent
 * updates from BPF programs. Called from bpf syscall and mostly used with
 * size 8 or 16 bytes, so ask compiler to inline it.
 */
static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
{
        const long *lsrc = src;
        long *ldst = dst;

        size /= sizeof(long);
        while (size--)
                *ldst++ = *lsrc++;
}

/* verify correctness of eBPF program */
int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);

/* Return map's numa specified by userspace */
static inline int bpf_map_attr_numa_node(const union bpf_attr *attr)
{
        return (attr->map_flags & BPF_F_NUMA_NODE) ?
                attr->numa_node : NUMA_NO_NODE;
}

#else
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{
        return ERR_PTR(-EOPNOTSUPP);
}

static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
                                                 enum bpf_prog_type type)
{
        return ERR_PTR(-EOPNOTSUPP);
}
static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog,
                                                          int i)
{
        return ERR_PTR(-EOPNOTSUPP);
}

static inline void bpf_prog_put(struct bpf_prog *prog)
{
}

static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog)
{
        return ERR_PTR(-EOPNOTSUPP);
}

static inline void bpf_prog_sub(struct bpf_prog *prog, int i)
{
}

static inline struct bpf_prog *__must_check
bpf_prog_inc_not_zero(struct bpf_prog *prog)
{
        return ERR_PTR(-EOPNOTSUPP);
}

static inline int __bpf_prog_charge(struct user_struct *user, u32 pages)
{
        return 0;
}

static inline void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
{
}

static inline int bpf_obj_get_user(const char __user *pathname, int flags)
{
        return -EOPNOTSUPP;
}

#endif /* CONFIG_BPF_SYSCALL */

/* verifier prototypes for helper functions called from eBPF programs */
extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
extern const struct bpf_func_proto bpf_map_update_elem_proto;
extern const struct bpf_func_proto bpf_map_delete_elem_proto;

extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
extern const struct bpf_func_proto bpf_tail_call_proto;
extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
extern const struct bpf_func_proto bpf_get_current_comm_proto;
extern const struct bpf_func_proto bpf_get_stackid_proto;

/* Shared helpers among cBPF and eBPF. */
void bpf_user_rnd_init_once(void);
u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);

bool bpf_helper_changes_skb_data(void *func);
#endif /* _LINUX_BPF_H */