/* 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/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) */
  	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);

  };
  
  struct bpf_map {
  	atomic_t refcnt;
  	enum bpf_map_type map_type;
  	u32 key_size;
  	u32 value_size;
  	u32 max_entries;

  	u32 map_flags;

  	u32 pages;
  	struct user_struct *user;

  	const struct bpf_map_ops *ops;

  	struct work_struct work;

  	atomic_t usercnt;

  };
  
  struct bpf_map_type_list {
  	struct list_head list_node;

  	const struct bpf_map_ops *ops;

  	enum bpf_map_type type;
  };

  /* 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_STACK,	/* any pointer to eBPF program stack */

  	ARG_PTR_TO_RAW_STACK,	/* any pointer to eBPF program stack, area does not
  				 * need to be initialized, helper function must fill
  				 * all bytes or clear them in error case.
  				 */

  	ARG_CONST_STACK_SIZE,	/* number of bytes accessed from stack */

  	ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack 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 */
  enum bpf_reg_type {
  	NOT_INIT = 0,		 /* nothing was written into register */
  	UNKNOWN_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 */
  	FRAME_PTR,		 /* reg == frame_pointer */
  	PTR_TO_STACK,		 /* reg == frame_pointer + imm */
  	CONST_IMM,		 /* constant integer value */
  
  	/* PTR_TO_PACKET represents:
  	 * skb->data
  	 * skb->data + imm
  	 * skb->data + (u16) var
  	 * skb->data + (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) menas that 'imm' was added
  	 */
  	PTR_TO_PACKET,
  	PTR_TO_PACKET_END,	 /* skb->data + headlen */

  
  	/* PTR_TO_MAP_VALUE_ADJ is used for doing pointer math inside of a map
  	 * elem value.  We only allow this if we can statically verify that
  	 * access from this register are going to fall within the size of the
  	 * map element.
  	 */
  	PTR_TO_MAP_VALUE_ADJ,

  };

  struct bpf_prog;

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

  
  	/* 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,
  				enum bpf_reg_type *reg_type);

  	int (*gen_prologue)(struct bpf_insn *insn, bool direct_write,
  			    const struct bpf_prog *prog);

  	u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
  				  int src_reg, int ctx_off,

  				  struct bpf_insn *insn, struct bpf_prog *prog);

  };
  
  struct bpf_prog_type_list {
  	struct list_head list_node;

  	const struct bpf_verifier_ops *ops;

  	enum bpf_prog_type type;
  };

  struct bpf_prog_aux {
  	atomic_t refcnt;

  	u32 used_map_cnt;

  	u32 max_ctx_offset;

  	const struct bpf_verifier_ops *ops;

  	struct bpf_map **used_maps;

  	struct bpf_prog *prog;

  	struct user_struct *user;

  	union {
  		struct work_struct work;
  		struct rcu_head	rcu;
  	};

  };

  struct bpf_array {
  	struct bpf_map map;
  	u32 elem_size;
  	/* '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;
  };

  u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);

  u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);

  bool bpf_prog_array_compatible(struct bpf_array *array, const 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);

  #ifdef CONFIG_BPF_SYSCALL

  DECLARE_PER_CPU(int, bpf_prog_active);

  void bpf_register_prog_type(struct bpf_prog_type_list *tl);

  void bpf_register_map_type(struct bpf_map_type_list *tl);

  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 *bpf_prog_add(struct bpf_prog *prog, int i);

  struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);

  void bpf_prog_put(struct bpf_prog *prog);

  struct bpf_map *bpf_map_get_with_uref(u32 ufd);

  struct bpf_map *__bpf_map_get(struct fd f);

  struct bpf_map *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);

  extern int sysctl_unprivileged_bpf_disabled;

  int bpf_map_new_fd(struct bpf_map *map);
  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 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);
  void bpf_fd_array_map_clear(struct bpf_map *map);

  /* 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);

  #else

  static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
  {
  }
  
  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 *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 *bpf_prog_inc(struct bpf_prog *prog)
  {
  	return ERR_PTR(-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_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_skb_vlan_push_proto;
  extern const struct bpf_func_proto bpf_skb_vlan_pop_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);

  #endif /* _LINUX_BPF_H */