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
  15 struct bpf_map;
  16
  17 /* map is generic key/value storage optionally accesible by eBPF programs */
  18 struct bpf_map_ops {
  19         /* funcs callable from userspace (via syscall) */
  20         struct bpf_map *(*map_alloc)(union bpf_attr *attr);
  21         void (*map_free)(struct bpf_map *);
  22         int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
  23
  24         /* funcs callable from userspace and from eBPF programs */
  25         void *(*map_lookup_elem)(struct bpf_map *map, void *key);
  26         int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
  27         int (*map_delete_elem)(struct bpf_map *map, void *key);
  28
  29         /* funcs called by prog_array and perf_event_array map */
  30         void *(*map_fd_get_ptr) (struct bpf_map *map, int fd);
  31         void (*map_fd_put_ptr) (void *ptr);
  32 };
  33
  34 struct bpf_map {
  35         atomic_t refcnt;
  36         enum bpf_map_type map_type;
  37         u32 key_size;
  38         u32 value_size;
  39         u32 max_entries;
  40         u32 map_flags;
  41         u32 pages;
  42         struct user_struct *user;
  43         const struct bpf_map_ops *ops;
  44         struct work_struct work;
  45         atomic_t usercnt;
  46 };
  47
  48 struct bpf_map_type_list {
  49         struct list_head list_node;
  50         const struct bpf_map_ops *ops;
  51         enum bpf_map_type type;
  52 };
  53
  54 /* function argument constraints */
  55 enum bpf_arg_type {
  56         ARG_DONTCARE = 0,       /* unused argument in helper function */
  57
  58         /* the following constraints used to prototype
  59          * bpf_map_lookup/update/delete_elem() functions
  60          */
  61         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  62         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  63         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  64
  65         /* the following constraints used to prototype bpf_memcmp() and other
  66          * functions that access data on eBPF program stack
  67          */
  68         ARG_PTR_TO_STACK,       /* any pointer to eBPF program stack */
  69         ARG_PTR_TO_RAW_STACK,   /* any pointer to eBPF program stack, area does not
  70                                  * need to be initialized, helper function must fill
  71                                  * all bytes or clear them in error case.
  72                                  */
  73
  74         ARG_CONST_STACK_SIZE,   /* number of bytes accessed from stack */
  75         ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack or 0 */
  76
  77         ARG_PTR_TO_CTX,         /* pointer to context */
  78         ARG_ANYTHING,           /* any (initialized) argument is ok */
  79 };
  80
  81 /* type of values returned from helper functions */
  82 enum bpf_return_type {
  83         RET_INTEGER,                    /* function returns integer */
  84         RET_VOID,                       /* function doesn't return anything */
  85         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  86 };
  87
  88 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  89  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  90  * instructions after verifying
  91  */
  92 struct bpf_func_proto {
  93         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  94         bool gpl_only;
  95         enum bpf_return_type ret_type;
  96         enum bpf_arg_type arg1_type;
  97         enum bpf_arg_type arg2_type;
  98         enum bpf_arg_type arg3_type;
  99         enum bpf_arg_type arg4_type;
 100         enum bpf_arg_type arg5_type;
 101 };
 102
 103 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
 104  * the first argument to eBPF programs.
 105  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
 106  */
 107 struct bpf_context;
 108
 109 enum bpf_access_type {
 110         BPF_READ = 1,
 111         BPF_WRITE = 2
 112 };
 113
 114 struct bpf_prog;
 115
 116 struct bpf_verifier_ops {
 117         /* return eBPF function prototype for verification */
 118         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 119
 120         /* return true if 'size' wide access at offset 'off' within bpf_context
 121          * with 'type' (read or write) is allowed
 122          */
 123         bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
 124
 125         u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
 126                                   int src_reg, int ctx_off,
 127                                   struct bpf_insn *insn, struct bpf_prog *prog);
 128 };
 129
 130 struct bpf_prog_type_list {
 131         struct list_head list_node;
 132         const struct bpf_verifier_ops *ops;
 133         enum bpf_prog_type type;
 134 };
 135
 136 struct bpf_prog_aux {
 137         atomic_t refcnt;
 138         u32 used_map_cnt;
 139         u32 max_ctx_offset;
 140         const struct bpf_verifier_ops *ops;
 141         struct bpf_map **used_maps;
 142         struct bpf_prog *prog;
 143         struct user_struct *user;
 144         union {
 145                 struct work_struct work;
 146                 struct rcu_head rcu;
 147         };
 148 };
 149
 150 struct bpf_array {
 151         struct bpf_map map;
 152         u32 elem_size;
 153         /* 'ownership' of prog_array is claimed by the first program that
 154          * is going to use this map or by the first program which FD is stored
 155          * in the map to make sure that all callers and callees have the same
 156          * prog_type and JITed flag
 157          */
 158         enum bpf_prog_type owner_prog_type;
 159         bool owner_jited;
 160         union {
 161                 char value[0] __aligned(8);
 162                 void *ptrs[0] __aligned(8);
 163                 void __percpu *pptrs[0] __aligned(8);
 164         };
 165 };
 166 #define MAX_TAIL_CALL_CNT 32
 167
 168 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 169 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 170 void bpf_fd_array_map_clear(struct bpf_map *map);
 171 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
 172
 173 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 174 const struct bpf_func_proto *bpf_get_event_output_proto(void);
 175
 176 #ifdef CONFIG_BPF_SYSCALL
 177 DECLARE_PER_CPU(int, bpf_prog_active);
 178
 179 void bpf_register_prog_type(struct bpf_prog_type_list *tl);
 180 void bpf_register_map_type(struct bpf_map_type_list *tl);
 181
 182 struct bpf_prog *bpf_prog_get(u32 ufd);
 183 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
 184 void bpf_prog_put(struct bpf_prog *prog);
 185 void bpf_prog_put_rcu(struct bpf_prog *prog);
 186
 187 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
 188 struct bpf_map *__bpf_map_get(struct fd f);
 189 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
 190 void bpf_map_put_with_uref(struct bpf_map *map);
 191 void bpf_map_put(struct bpf_map *map);
 192 int bpf_map_precharge_memlock(u32 pages);
 193
 194 extern int sysctl_unprivileged_bpf_disabled;
 195
 196 int bpf_map_new_fd(struct bpf_map *map);
 197 int bpf_prog_new_fd(struct bpf_prog *prog);
 198
 199 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
 200 int bpf_obj_get_user(const char __user *pathname);
 201
 202 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
 203 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
 204 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
 205                            u64 flags);
 206 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
 207                             u64 flags);
 208 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);
 209
 210 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
 211  * forced to use 'long' read/writes to try to atomically copy long counters.
 212  * Best-effort only.  No barriers here, since it _will_ race with concurrent
 213  * updates from BPF programs. Called from bpf syscall and mostly used with
 214  * size 8 or 16 bytes, so ask compiler to inline it.
 215  */
 216 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
 217 {
 218         const long *lsrc = src;
 219         long *ldst = dst;
 220
 221         size /= sizeof(long);
 222         while (size--)
 223                 *ldst++ = *lsrc++;
 224 }
 225
 226 /* verify correctness of eBPF program */
 227 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 228 #else
 229 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
 230 {
 231 }
 232
 233 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 234 {
 235         return ERR_PTR(-EOPNOTSUPP);
 236 }
 237
 238 static inline void bpf_prog_put(struct bpf_prog *prog)
 239 {
 240 }
 241 #endif /* CONFIG_BPF_SYSCALL */
 242
 243 /* verifier prototypes for helper functions called from eBPF programs */
 244 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
 245 extern const struct bpf_func_proto bpf_map_update_elem_proto;
 246 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
 247
 248 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
 249 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
 250 extern const struct bpf_func_proto bpf_tail_call_proto;
 251 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
 252 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
 253 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
 254 extern const struct bpf_func_proto bpf_get_current_comm_proto;
 255 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 256 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 257 extern const struct bpf_func_proto bpf_get_stackid_proto;
 258
 259 /* Shared helpers among cBPF and eBPF. */
 260 void bpf_user_rnd_init_once(void);
 261 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 262
 263 #endif /* _LINUX_BPF_H */