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