include/linux/bpf.h

   1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #ifndef _LINUX_BPF_H
   8 #define _LINUX_BPF_H 1
   9
  10 #include <uapi/linux/bpf.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/file.h>
  13
  14 struct bpf_map;
  15
  16 /* map is generic key/value storage optionally accesible by eBPF programs */
  17 struct bpf_map_ops {
  18         /* funcs callable from userspace (via syscall) */
  19         struct bpf_map *(*map_alloc)(union bpf_attr *attr);
  20         void (*map_free)(struct bpf_map *);
  21         int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
  22
  23         /* funcs callable from userspace and from eBPF programs */
  24         void *(*map_lookup_elem)(struct bpf_map *map, void *key);
  25         int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
  26         int (*map_delete_elem)(struct bpf_map *map, void *key);
  27
  28         /* funcs called by prog_array and perf_event_array map */
  29         void *(*map_fd_get_ptr) (struct bpf_map *map, int fd);
  30         void (*map_fd_put_ptr) (void *ptr);
  31 };
  32
  33 struct bpf_map {
  34         atomic_t refcnt;
  35         enum bpf_map_type map_type;
  36         u32 key_size;
  37         u32 value_size;
  38         u32 max_entries;
  39         u32 pages;
  40         struct user_struct *user;
  41         const struct bpf_map_ops *ops;
  42         struct work_struct work;
  43         atomic_t usercnt;
  44 };
  45
  46 struct bpf_map_type_list {
  47         struct list_head list_node;
  48         const struct bpf_map_ops *ops;
  49         enum bpf_map_type type;
  50 };
  51
  52 /* function argument constraints */
  53 enum bpf_arg_type {
  54         ARG_DONTCARE = 0,       /* unused argument in helper function */
  55
  56         /* the following constraints used to prototype
  57          * bpf_map_lookup/update/delete_elem() functions
  58          */
  59         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  60         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  61         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  62
  63         /* the following constraints used to prototype bpf_memcmp() and other
  64          * functions that access data on eBPF program stack
  65          */
  66         ARG_PTR_TO_STACK,       /* any pointer to eBPF program stack */
  67         ARG_CONST_STACK_SIZE,   /* number of bytes accessed from stack */
  68
  69         ARG_PTR_TO_CTX,         /* pointer to context */
  70         ARG_ANYTHING,           /* any (initialized) argument is ok */
  71 };
  72
  73 /* type of values returned from helper functions */
  74 enum bpf_return_type {
  75         RET_INTEGER,                    /* function returns integer */
  76         RET_VOID,                       /* function doesn't return anything */
  77         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  78 };
  79
  80 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  81  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  82  * instructions after verifying
  83  */
  84 struct bpf_func_proto {
  85         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  86         bool gpl_only;
  87         enum bpf_return_type ret_type;
  88         enum bpf_arg_type arg1_type;
  89         enum bpf_arg_type arg2_type;
  90         enum bpf_arg_type arg3_type;
  91         enum bpf_arg_type arg4_type;
  92         enum bpf_arg_type arg5_type;
  93 };
  94
  95 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
  96  * the first argument to eBPF programs.
  97  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
  98  */
  99 struct bpf_context;
 100
 101 enum bpf_access_type {
 102         BPF_READ = 1,
 103         BPF_WRITE = 2
 104 };
 105
 106 struct bpf_prog;
 107
 108 struct bpf_verifier_ops {
 109         /* return eBPF function prototype for verification */
 110         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 111
 112         /* return true if 'size' wide access at offset 'off' within bpf_context
 113          * with 'type' (read or write) is allowed
 114          */
 115         bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
 116
 117         u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
 118                                   int src_reg, int ctx_off,
 119                                   struct bpf_insn *insn, struct bpf_prog *prog);
 120 };
 121
 122 struct bpf_prog_type_list {
 123         struct list_head list_node;
 124         const struct bpf_verifier_ops *ops;
 125         enum bpf_prog_type type;
 126 };
 127
 128 struct bpf_prog_aux {
 129         atomic_t refcnt;
 130         u32 used_map_cnt;
 131         const struct bpf_verifier_ops *ops;
 132         struct bpf_map **used_maps;
 133         struct bpf_prog *prog;
 134         struct user_struct *user;
 135         union {
 136                 struct work_struct work;
 137                 struct rcu_head rcu;
 138         };
 139 };
 140
 141 struct bpf_array {
 142         struct bpf_map map;
 143         u32 elem_size;
 144         /* 'ownership' of prog_array is claimed by the first program that
 145          * is going to use this map or by the first program which FD is stored
 146          * in the map to make sure that all callers and callees have the same
 147          * prog_type and JITed flag
 148          */
 149         enum bpf_prog_type owner_prog_type;
 150         bool owner_jited;
 151         union {
 152                 char value[0] __aligned(8);
 153                 void *ptrs[0] __aligned(8);
 154         };
 155 };
 156 #define MAX_TAIL_CALL_CNT 32
 157
 158 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 159 void bpf_fd_array_map_clear(struct bpf_map *map);
 160 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
 161 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 162
 163 #ifdef CONFIG_BPF_SYSCALL
 164 void bpf_register_prog_type(struct bpf_prog_type_list *tl);
 165 void bpf_register_map_type(struct bpf_map_type_list *tl);
 166
 167 struct bpf_prog *bpf_prog_get(u32 ufd);
 168 void bpf_prog_put(struct bpf_prog *prog);
 169 void bpf_prog_put_rcu(struct bpf_prog *prog);
 170
 171 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 172 struct bpf_map *__bpf_map_get(struct fd f);
 173 void bpf_map_inc(struct bpf_map *map, bool uref);
 174 void bpf_map_put_with_uref(struct bpf_map *map);
 175 void bpf_map_put(struct bpf_map *map);
 176
 177 extern int sysctl_unprivileged_bpf_disabled;
 178
 179 int bpf_map_new_fd(struct bpf_map *map);
 180 int bpf_prog_new_fd(struct bpf_prog *prog);
 181
 182 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
 183 int bpf_obj_get_user(const char __user *pathname);
 184
 185 /* verify correctness of eBPF program */
 186 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 187 #else
 188 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
 189 {
 190 }
 191
 192 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 193 {
 194         return ERR_PTR(-EOPNOTSUPP);
 195 }
 196
 197 static inline void bpf_prog_put(struct bpf_prog *prog)
 198 {
 199 }
 200 #endif /* CONFIG_BPF_SYSCALL */
 201
 202 /* verifier prototypes for helper functions called from eBPF programs */
 203 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
 204 extern const struct bpf_func_proto bpf_map_update_elem_proto;
 205 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
 206
 207 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
 208 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
 209 extern const struct bpf_func_proto bpf_tail_call_proto;
 210 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
 211 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
 212 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
 213 extern const struct bpf_func_proto bpf_get_current_comm_proto;
 214 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 215 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 216
 217 /* Shared helpers among cBPF and eBPF. */
 218 void bpf_user_rnd_init_once(void);
 219 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 220
 221 #endif /* _LINUX_BPF_H */