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