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