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
  12 #include <linux/workqueue.h>
  13 #include <linux/file.h>
  14 #include <linux/percpu.h>
  15 #include <linux/err.h>
  16 #include <linux/rbtree_latch.h>
  17
  18 struct perf_event;
  19 struct bpf_map;
  20
  21 /* map is generic key/value storage optionally accesible by eBPF programs */
  22 struct bpf_map_ops {
  23         /* funcs callable from userspace (via syscall) */
  24         struct bpf_map *(*map_alloc)(union bpf_attr *attr);
  25         void (*map_release)(struct bpf_map *map, struct file *map_file);
  26         void (*map_free)(struct bpf_map *map);
  27         int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
  28
  29         /* funcs callable from userspace and from eBPF programs */
  30         void *(*map_lookup_elem)(struct bpf_map *map, void *key);
  31         int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
  32         int (*map_delete_elem)(struct bpf_map *map, void *key);
  33
  34         /* funcs called by prog_array and perf_event_array map */
  35         void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file,
  36                                 int fd);
  37         void (*map_fd_put_ptr)(void *ptr);
  38         u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
  39 };
  40
  41 struct bpf_map {
  42         atomic_t refcnt;
  43         enum bpf_map_type map_type;
  44         u32 key_size;
  45         u32 value_size;
  46         u32 max_entries;
  47         u32 map_flags;
  48         u32 pages;
  49         u32 id;
  50         struct user_struct *user;
  51         const struct bpf_map_ops *ops;
  52         struct work_struct work;
  53         atomic_t usercnt;
  54         struct bpf_map *inner_map_meta;
  55 };
  56
  57 /* function argument constraints */
  58 enum bpf_arg_type {
  59         ARG_DONTCARE = 0,       /* unused argument in helper function */
  60
  61         /* the following constraints used to prototype
  62          * bpf_map_lookup/update/delete_elem() functions
  63          */
  64         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  65         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  66         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  67
  68         /* the following constraints used to prototype bpf_memcmp() and other
  69          * functions that access data on eBPF program stack
  70          */
  71         ARG_PTR_TO_MEM,         /* pointer to valid memory (stack, packet, map value) */
  72         ARG_PTR_TO_UNINIT_MEM,  /* pointer to memory does not need to be initialized,
  73                                  * helper function must fill all bytes or clear
  74                                  * them in error case.
  75                                  */
  76
  77         ARG_CONST_SIZE,         /* number of bytes accessed from memory */
  78         ARG_CONST_SIZE_OR_ZERO, /* number of bytes accessed from memory or 0 */
  79
  80         ARG_PTR_TO_CTX,         /* pointer to context */
  81         ARG_ANYTHING,           /* any (initialized) argument is ok */
  82 };
  83
  84 /* type of values returned from helper functions */
  85 enum bpf_return_type {
  86         RET_INTEGER,                    /* function returns integer */
  87         RET_VOID,                       /* function doesn't return anything */
  88         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  89 };
  90
  91 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  92  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  93  * instructions after verifying
  94  */
  95 struct bpf_func_proto {
  96         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  97         bool gpl_only;
  98         bool pkt_access;
  99         enum bpf_return_type ret_type;
 100         enum bpf_arg_type arg1_type;
 101         enum bpf_arg_type arg2_type;
 102         enum bpf_arg_type arg3_type;
 103         enum bpf_arg_type arg4_type;
 104         enum bpf_arg_type arg5_type;
 105 };
 106
 107 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
 108  * the first argument to eBPF programs.
 109  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
 110  */
 111 struct bpf_context;
 112
 113 enum bpf_access_type {
 114         BPF_READ = 1,
 115         BPF_WRITE = 2
 116 };
 117
 118 /* types of values stored in eBPF registers */
 119 enum bpf_reg_type {
 120         NOT_INIT = 0,            /* nothing was written into register */
 121         UNKNOWN_VALUE,           /* reg doesn't contain a valid pointer */
 122         PTR_TO_CTX,              /* reg points to bpf_context */
 123         CONST_PTR_TO_MAP,        /* reg points to struct bpf_map */
 124         PTR_TO_MAP_VALUE,        /* reg points to map element value */
 125         PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
 126         FRAME_PTR,               /* reg == frame_pointer */
 127         PTR_TO_STACK,            /* reg == frame_pointer + imm */
 128         CONST_IMM,               /* constant integer value */
 129
 130         /* PTR_TO_PACKET represents:
 131          * skb->data
 132          * skb->data + imm
 133          * skb->data + (u16) var
 134          * skb->data + (u16) var + imm
 135          * if (range > 0) then [ptr, ptr + range - off) is safe to access
 136          * if (id > 0) means that some 'var' was added
 137          * if (off > 0) menas that 'imm' was added
 138          */
 139         PTR_TO_PACKET,
 140         PTR_TO_PACKET_END,       /* skb->data + headlen */
 141
 142         /* PTR_TO_MAP_VALUE_ADJ is used for doing pointer math inside of a map
 143          * elem value.  We only allow this if we can statically verify that
 144          * access from this register are going to fall within the size of the
 145          * map element.
 146          */
 147         PTR_TO_MAP_VALUE_ADJ,
 148 };
 149
 150 struct bpf_prog;
 151
 152 struct bpf_verifier_ops {
 153         /* return eBPF function prototype for verification */
 154         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 155
 156         /* return true if 'size' wide access at offset 'off' within bpf_context
 157          * with 'type' (read or write) is allowed
 158          */
 159         bool (*is_valid_access)(int off, int size, enum bpf_access_type type,
 160                                 enum bpf_reg_type *reg_type, int *ctx_field_size);
 161         int (*gen_prologue)(struct bpf_insn *insn, bool direct_write,
 162                             const struct bpf_prog *prog);
 163         u32 (*convert_ctx_access)(enum bpf_access_type type,
 164                                   const struct bpf_insn *src,
 165                                   struct bpf_insn *dst,
 166                                   struct bpf_prog *prog);
 167         int (*test_run)(struct bpf_prog *prog, const union bpf_attr *kattr,
 168                         union bpf_attr __user *uattr);
 169 };
 170
 171 struct bpf_prog_aux {
 172         atomic_t refcnt;
 173         u32 used_map_cnt;
 174         u32 max_ctx_offset;
 175         u32 stack_depth;
 176         u32 id;
 177         struct latch_tree_node ksym_tnode;
 178         struct list_head ksym_lnode;
 179         const struct bpf_verifier_ops *ops;
 180         struct bpf_map **used_maps;
 181         struct bpf_prog *prog;
 182         struct user_struct *user;
 183         union {
 184                 struct work_struct work;
 185                 struct rcu_head rcu;
 186         };
 187 };
 188
 189 struct bpf_array {
 190         struct bpf_map map;
 191         u32 elem_size;
 192         /* 'ownership' of prog_array is claimed by the first program that
 193          * is going to use this map or by the first program which FD is stored
 194          * in the map to make sure that all callers and callees have the same
 195          * prog_type and JITed flag
 196          */
 197         enum bpf_prog_type owner_prog_type;
 198         bool owner_jited;
 199         union {
 200                 char value[0] __aligned(8);
 201                 void *ptrs[0] __aligned(8);
 202                 void __percpu *pptrs[0] __aligned(8);
 203         };
 204 };
 205
 206 #define MAX_TAIL_CALL_CNT 32
 207
 208 struct bpf_event_entry {
 209         struct perf_event *event;
 210         struct file *perf_file;
 211         struct file *map_file;
 212         struct rcu_head rcu;
 213 };
 214
 215 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 216 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 217
 218 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
 219 int bpf_prog_calc_tag(struct bpf_prog *fp);
 220
 221 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 222
 223 typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src,
 224                                         unsigned long off, unsigned long len);
 225
 226 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 227                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy);
 228
 229 int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 230                           union bpf_attr __user *uattr);
 231 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 232                           union bpf_attr __user *uattr);
 233
 234 #ifdef CONFIG_BPF_SYSCALL
 235 DECLARE_PER_CPU(int, bpf_prog_active);
 236
 237 #define BPF_PROG_TYPE(_id, _ops) \
 238         extern const struct bpf_verifier_ops _ops;
 239 #define BPF_MAP_TYPE(_id, _ops) \
 240         extern const struct bpf_map_ops _ops;
 241 #include <linux/bpf_types.h>
 242 #undef BPF_PROG_TYPE
 243 #undef BPF_MAP_TYPE
 244
 245 struct bpf_prog *bpf_prog_get(u32 ufd);
 246 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
 247 struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
 248 void bpf_prog_sub(struct bpf_prog *prog, int i);
 249 struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
 250 void bpf_prog_put(struct bpf_prog *prog);
 251 int __bpf_prog_charge(struct user_struct *user, u32 pages);
 252 void __bpf_prog_uncharge(struct user_struct *user, u32 pages);
 253
 254 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 255 struct bpf_map *__bpf_map_get(struct fd f);
 256 struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref);
 257 void bpf_map_put_with_uref(struct bpf_map *map);
 258 void bpf_map_put(struct bpf_map *map);
 259 int bpf_map_precharge_memlock(u32 pages);
 260 void *bpf_map_area_alloc(size_t size);
 261 void bpf_map_area_free(void *base);
 262
 263 extern int sysctl_unprivileged_bpf_disabled;
 264
 265 int bpf_map_new_fd(struct bpf_map *map);
 266 int bpf_prog_new_fd(struct bpf_prog *prog);
 267
 268 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
 269 int bpf_obj_get_user(const char __user *pathname);
 270
 271 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
 272 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
 273 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
 274                            u64 flags);
 275 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
 276                             u64 flags);
 277
 278 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);
 279
 280 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
 281                                  void *key, void *value, u64 map_flags);
 282 void bpf_fd_array_map_clear(struct bpf_map *map);
 283 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
 284                                 void *key, void *value, u64 map_flags);
 285
 286 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
 287  * forced to use 'long' read/writes to try to atomically copy long counters.
 288  * Best-effort only.  No barriers here, since it _will_ race with concurrent
 289  * updates from BPF programs. Called from bpf syscall and mostly used with
 290  * size 8 or 16 bytes, so ask compiler to inline it.
 291  */
 292 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
 293 {
 294         const long *lsrc = src;
 295         long *ldst = dst;
 296
 297         size /= sizeof(long);
 298         while (size--)
 299                 *ldst++ = *lsrc++;
 300 }
 301
 302 /* verify correctness of eBPF program */
 303 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 304 #else
 305 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 306 {
 307         return ERR_PTR(-EOPNOTSUPP);
 308 }
 309
 310 static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
 311                                                  enum bpf_prog_type type)
 312 {
 313         return ERR_PTR(-EOPNOTSUPP);
 314 }
 315 static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog,
 316                                                           int i)
 317 {
 318         return ERR_PTR(-EOPNOTSUPP);
 319 }
 320
 321 static inline void bpf_prog_sub(struct bpf_prog *prog, int i)
 322 {
 323 }
 324
 325 static inline void bpf_prog_put(struct bpf_prog *prog)
 326 {
 327 }
 328
 329 static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog)
 330 {
 331         return ERR_PTR(-EOPNOTSUPP);
 332 }
 333
 334 static inline int __bpf_prog_charge(struct user_struct *user, u32 pages)
 335 {
 336         return 0;
 337 }
 338
 339 static inline void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
 340 {
 341 }
 342 #endif /* CONFIG_BPF_SYSCALL */
 343
 344 /* verifier prototypes for helper functions called from eBPF programs */
 345 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
 346 extern const struct bpf_func_proto bpf_map_update_elem_proto;
 347 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
 348
 349 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
 350 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
 351 extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
 352 extern const struct bpf_func_proto bpf_tail_call_proto;
 353 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
 354 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
 355 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
 356 extern const struct bpf_func_proto bpf_get_current_comm_proto;
 357 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 358 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 359 extern const struct bpf_func_proto bpf_get_stackid_proto;
 360
 361 /* Shared helpers among cBPF and eBPF. */
 362 void bpf_user_rnd_init_once(void);
 363 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 364
 365 #endif /* _LINUX_BPF_H */