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 #include <linux/numa.h>
  18
  19 struct perf_event;
  20 struct bpf_prog;
  21 struct bpf_map;
  22
  23 /* map is generic key/value storage optionally accesible by eBPF programs */
  24 struct bpf_map_ops {
  25         /* funcs callable from userspace (via syscall) */
  26         struct bpf_map *(*map_alloc)(union bpf_attr *attr);
  27         void (*map_release)(struct bpf_map *map, struct file *map_file);
  28         void (*map_free)(struct bpf_map *map);
  29         int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
  30
  31         /* funcs callable from userspace and from eBPF programs */
  32         void *(*map_lookup_elem)(struct bpf_map *map, void *key);
  33         int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
  34         int (*map_delete_elem)(struct bpf_map *map, void *key);
  35
  36         /* funcs called by prog_array and perf_event_array map */
  37         void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file,
  38                                 int fd);
  39         void (*map_fd_put_ptr)(void *ptr);
  40         u32 (*map_gen_lookup)(struct bpf_map *map, struct bpf_insn *insn_buf);
  41         u32 (*map_fd_sys_lookup_elem)(void *ptr);
  42 };
  43
  44 struct bpf_map {
  45         atomic_t refcnt;
  46         enum bpf_map_type map_type;
  47         u32 key_size;
  48         u32 value_size;
  49         u32 max_entries;
  50         u32 map_flags;
  51         u32 pages;
  52         u32 id;
  53         int numa_node;
  54         struct user_struct *user;
  55         const struct bpf_map_ops *ops;
  56         struct work_struct work;
  57         atomic_t usercnt;
  58         struct bpf_map *inner_map_meta;
  59 };
  60
  61 /* function argument constraints */
  62 enum bpf_arg_type {
  63         ARG_DONTCARE = 0,       /* unused argument in helper function */
  64
  65         /* the following constraints used to prototype
  66          * bpf_map_lookup/update/delete_elem() functions
  67          */
  68         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  69         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  70         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  71
  72         /* the following constraints used to prototype bpf_memcmp() and other
  73          * functions that access data on eBPF program stack
  74          */
  75         ARG_PTR_TO_MEM,         /* pointer to valid memory (stack, packet, map value) */
  76         ARG_PTR_TO_UNINIT_MEM,  /* pointer to memory does not need to be initialized,
  77                                  * helper function must fill all bytes or clear
  78                                  * them in error case.
  79                                  */
  80
  81         ARG_CONST_SIZE,         /* number of bytes accessed from memory */
  82         ARG_CONST_SIZE_OR_ZERO, /* number of bytes accessed from memory or 0 */
  83
  84         ARG_PTR_TO_CTX,         /* pointer to context */
  85         ARG_ANYTHING,           /* any (initialized) argument is ok */
  86 };
  87
  88 /* type of values returned from helper functions */
  89 enum bpf_return_type {
  90         RET_INTEGER,                    /* function returns integer */
  91         RET_VOID,                       /* function doesn't return anything */
  92         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  93 };
  94
  95 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  96  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  97  * instructions after verifying
  98  */
  99 struct bpf_func_proto {
 100         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 101         bool gpl_only;
 102         bool pkt_access;
 103         enum bpf_return_type ret_type;
 104         enum bpf_arg_type arg1_type;
 105         enum bpf_arg_type arg2_type;
 106         enum bpf_arg_type arg3_type;
 107         enum bpf_arg_type arg4_type;
 108         enum bpf_arg_type arg5_type;
 109 };
 110
 111 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
 112  * the first argument to eBPF programs.
 113  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
 114  */
 115 struct bpf_context;
 116
 117 enum bpf_access_type {
 118         BPF_READ = 1,
 119         BPF_WRITE = 2
 120 };
 121
 122 /* types of values stored in eBPF registers */
 123 /* Pointer types represent:
 124  * pointer
 125  * pointer + imm
 126  * pointer + (u16) var
 127  * pointer + (u16) var + imm
 128  * if (range > 0) then [ptr, ptr + range - off) is safe to access
 129  * if (id > 0) means that some 'var' was added
 130  * if (off > 0) means that 'imm' was added
 131  */
 132 enum bpf_reg_type {
 133         NOT_INIT = 0,            /* nothing was written into register */
 134         SCALAR_VALUE,            /* reg doesn't contain a valid pointer */
 135         PTR_TO_CTX,              /* reg points to bpf_context */
 136         CONST_PTR_TO_MAP,        /* reg points to struct bpf_map */
 137         PTR_TO_MAP_VALUE,        /* reg points to map element value */
 138         PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
 139         PTR_TO_STACK,            /* reg == frame_pointer + offset */
 140         PTR_TO_PACKET,           /* reg points to skb->data */
 141         PTR_TO_PACKET_END,       /* skb->data + headlen */
 142 };
 143
 144 /* The information passed from prog-specific *_is_valid_access
 145  * back to the verifier.
 146  */
 147 struct bpf_insn_access_aux {
 148         enum bpf_reg_type reg_type;
 149         int ctx_field_size;
 150 };
 151
 152 static inline void
 153 bpf_ctx_record_field_size(struct bpf_insn_access_aux *aux, u32 size)
 154 {
 155         aux->ctx_field_size = size;
 156 }
 157
 158 struct bpf_verifier_ops {
 159         /* return eBPF function prototype for verification */
 160         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 161
 162         /* return true if 'size' wide access at offset 'off' within bpf_context
 163          * with 'type' (read or write) is allowed
 164          */
 165         bool (*is_valid_access)(int off, int size, enum bpf_access_type type,
 166                                 struct bpf_insn_access_aux *info);
 167         int (*gen_prologue)(struct bpf_insn *insn, bool direct_write,
 168                             const struct bpf_prog *prog);
 169         u32 (*convert_ctx_access)(enum bpf_access_type type,
 170                                   const struct bpf_insn *src,
 171                                   struct bpf_insn *dst,
 172                                   struct bpf_prog *prog, u32 *target_size);
 173         int (*test_run)(struct bpf_prog *prog, const union bpf_attr *kattr,
 174                         union bpf_attr __user *uattr);
 175 };
 176
 177 struct bpf_prog_aux {
 178         atomic_t refcnt;
 179         u32 used_map_cnt;
 180         u32 max_ctx_offset;
 181         u32 stack_depth;
 182         u32 id;
 183         struct latch_tree_node ksym_tnode;
 184         struct list_head ksym_lnode;
 185         const struct bpf_verifier_ops *ops;
 186         struct bpf_map **used_maps;
 187         struct bpf_prog *prog;
 188         struct user_struct *user;
 189         union {
 190                 struct work_struct work;
 191                 struct rcu_head rcu;
 192         };
 193 };
 194
 195 struct bpf_array {
 196         struct bpf_map map;
 197         u32 elem_size;
 198         /* 'ownership' of prog_array is claimed by the first program that
 199          * is going to use this map or by the first program which FD is stored
 200          * in the map to make sure that all callers and callees have the same
 201          * prog_type and JITed flag
 202          */
 203         enum bpf_prog_type owner_prog_type;
 204         bool owner_jited;
 205         union {
 206                 char value[0] __aligned(8);
 207                 void *ptrs[0] __aligned(8);
 208                 void __percpu *pptrs[0] __aligned(8);
 209         };
 210 };
 211
 212 #define MAX_TAIL_CALL_CNT 32
 213
 214 struct bpf_event_entry {
 215         struct perf_event *event;
 216         struct file *perf_file;
 217         struct file *map_file;
 218         struct rcu_head rcu;
 219 };
 220
 221 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 222 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 223
 224 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
 225 int bpf_prog_calc_tag(struct bpf_prog *fp);
 226
 227 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 228
 229 typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src,
 230                                         unsigned long off, unsigned long len);
 231
 232 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
 233                      void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy);
 234
 235 int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 236                           union bpf_attr __user *uattr);
 237 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 238                           union bpf_attr __user *uattr);
 239
 240 #ifdef CONFIG_BPF_SYSCALL
 241 DECLARE_PER_CPU(int, bpf_prog_active);
 242
 243 #define BPF_PROG_TYPE(_id, _ops) \
 244         extern const struct bpf_verifier_ops _ops;
 245 #define BPF_MAP_TYPE(_id, _ops) \
 246         extern const struct bpf_map_ops _ops;
 247 #include <linux/bpf_types.h>
 248 #undef BPF_PROG_TYPE
 249 #undef BPF_MAP_TYPE
 250
 251 struct bpf_prog *bpf_prog_get(u32 ufd);
 252 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
 253 struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
 254 void bpf_prog_sub(struct bpf_prog *prog, int i);
 255 struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
 256 struct bpf_prog * __must_check bpf_prog_inc_not_zero(struct bpf_prog *prog);
 257 void bpf_prog_put(struct bpf_prog *prog);
 258 int __bpf_prog_charge(struct user_struct *user, u32 pages);
 259 void __bpf_prog_uncharge(struct user_struct *user, u32 pages);
 260
 261 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 262 struct bpf_map *__bpf_map_get(struct fd f);
 263 struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref);
 264 void bpf_map_put_with_uref(struct bpf_map *map);
 265 void bpf_map_put(struct bpf_map *map);
 266 int bpf_map_precharge_memlock(u32 pages);
 267 void *bpf_map_area_alloc(size_t size, int numa_node);
 268 void bpf_map_area_free(void *base);
 269
 270 extern int sysctl_unprivileged_bpf_disabled;
 271
 272 int bpf_map_new_fd(struct bpf_map *map);
 273 int bpf_prog_new_fd(struct bpf_prog *prog);
 274
 275 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
 276 int bpf_obj_get_user(const char __user *pathname);
 277
 278 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
 279 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
 280 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
 281                            u64 flags);
 282 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
 283                             u64 flags);
 284
 285 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);
 286
 287 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
 288                                  void *key, void *value, u64 map_flags);
 289 int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
 290 void bpf_fd_array_map_clear(struct bpf_map *map);
 291 int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
 292                                 void *key, void *value, u64 map_flags);
 293 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
 294
 295 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
 296  * forced to use 'long' read/writes to try to atomically copy long counters.
 297  * Best-effort only.  No barriers here, since it _will_ race with concurrent
 298  * updates from BPF programs. Called from bpf syscall and mostly used with
 299  * size 8 or 16 bytes, so ask compiler to inline it.
 300  */
 301 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
 302 {
 303         const long *lsrc = src;
 304         long *ldst = dst;
 305
 306         size /= sizeof(long);
 307         while (size--)
 308                 *ldst++ = *lsrc++;
 309 }
 310
 311 /* verify correctness of eBPF program */
 312 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 313
 314 /* Map specifics */
 315 struct net_device  *__dev_map_lookup_elem(struct bpf_map *map, u32 key);
 316 void __dev_map_insert_ctx(struct bpf_map *map, u32 index);
 317 void __dev_map_flush(struct bpf_map *map);
 318
 319 /* Return map's numa specified by userspace */
 320 static inline int bpf_map_attr_numa_node(const union bpf_attr *attr)
 321 {
 322         return (attr->map_flags & BPF_F_NUMA_NODE) ?
 323                 attr->numa_node : NUMA_NO_NODE;
 324 }
 325
 326 #else
 327 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 328 {
 329         return ERR_PTR(-EOPNOTSUPP);
 330 }
 331
 332 static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
 333                                                  enum bpf_prog_type type)
 334 {
 335         return ERR_PTR(-EOPNOTSUPP);
 336 }
 337 static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog,
 338                                                           int i)
 339 {
 340         return ERR_PTR(-EOPNOTSUPP);
 341 }
 342
 343 static inline void bpf_prog_sub(struct bpf_prog *prog, int i)
 344 {
 345 }
 346
 347 static inline void bpf_prog_put(struct bpf_prog *prog)
 348 {
 349 }
 350
 351 static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog)
 352 {
 353         return ERR_PTR(-EOPNOTSUPP);
 354 }
 355
 356 static inline struct bpf_prog *__must_check
 357 bpf_prog_inc_not_zero(struct bpf_prog *prog)
 358 {
 359         return ERR_PTR(-EOPNOTSUPP);
 360 }
 361
 362 static inline int __bpf_prog_charge(struct user_struct *user, u32 pages)
 363 {
 364         return 0;
 365 }
 366
 367 static inline void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
 368 {
 369 }
 370
 371 static inline int bpf_obj_get_user(const char __user *pathname)
 372 {
 373         return -EOPNOTSUPP;
 374 }
 375
 376 static inline struct net_device  *__dev_map_lookup_elem(struct bpf_map *map,
 377                                                        u32 key)
 378 {
 379         return NULL;
 380 }
 381
 382 static inline void __dev_map_insert_ctx(struct bpf_map *map, u32 index)
 383 {
 384 }
 385
 386 static inline void __dev_map_flush(struct bpf_map *map)
 387 {
 388 }
 389 #endif /* CONFIG_BPF_SYSCALL */
 390
 391 #if defined(CONFIG_STREAM_PARSER) && defined(CONFIG_BPF_SYSCALL)
 392 struct sock  *__sock_map_lookup_elem(struct bpf_map *map, u32 key);
 393 int sock_map_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type);
 394 #else
 395 static inline struct sock  *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
 396 {
 397         return NULL;
 398 }
 399
 400 static inline int sock_map_prog(struct bpf_map *map,
 401                                 struct bpf_prog *prog,
 402                                 u32 type)
 403 {
 404         return -EOPNOTSUPP;
 405 }
 406 #endif
 407
 408 /* verifier prototypes for helper functions called from eBPF programs */
 409 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
 410 extern const struct bpf_func_proto bpf_map_update_elem_proto;
 411 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
 412
 413 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
 414 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
 415 extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
 416 extern const struct bpf_func_proto bpf_tail_call_proto;
 417 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
 418 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
 419 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
 420 extern const struct bpf_func_proto bpf_get_current_comm_proto;
 421 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 422 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 423 extern const struct bpf_func_proto bpf_get_stackid_proto;
 424 extern const struct bpf_func_proto bpf_sock_map_update_proto;
 425
 426 /* Shared helpers among cBPF and eBPF. */
 427 void bpf_user_rnd_init_once(void);
 428 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 429
 430 #endif /* _LINUX_BPF_H */