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