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/perf_event.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         const struct bpf_map_ops *ops;
  41         struct work_struct work;
  42 };
  43
  44 struct bpf_map_type_list {
  45         struct list_head list_node;
  46         const struct bpf_map_ops *ops;
  47         enum bpf_map_type type;
  48 };
  49
  50 /* function argument constraints */
  51 enum bpf_arg_type {
  52         ARG_DONTCARE = 0,       /* unused argument in helper function */
  53
  54         /* the following constraints used to prototype
  55          * bpf_map_lookup/update/delete_elem() functions
  56          */
  57         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  58         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  59         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  60
  61         /* the following constraints used to prototype bpf_memcmp() and other
  62          * functions that access data on eBPF program stack
  63          */
  64         ARG_PTR_TO_STACK,       /* any pointer to eBPF program stack */
  65         ARG_CONST_STACK_SIZE,   /* number of bytes accessed from stack */
  66
  67         ARG_PTR_TO_CTX,         /* pointer to context */
  68         ARG_ANYTHING,           /* any (initialized) argument is ok */
  69 };
  70
  71 /* type of values returned from helper functions */
  72 enum bpf_return_type {
  73         RET_INTEGER,                    /* function returns integer */
  74         RET_VOID,                       /* function doesn't return anything */
  75         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  76 };
  77
  78 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  79  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  80  * instructions after verifying
  81  */
  82 struct bpf_func_proto {
  83         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  84         bool gpl_only;
  85         enum bpf_return_type ret_type;
  86         enum bpf_arg_type arg1_type;
  87         enum bpf_arg_type arg2_type;
  88         enum bpf_arg_type arg3_type;
  89         enum bpf_arg_type arg4_type;
  90         enum bpf_arg_type arg5_type;
  91 };
  92
  93 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
  94  * the first argument to eBPF programs.
  95  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
  96  */
  97 struct bpf_context;
  98
  99 enum bpf_access_type {
 100         BPF_READ = 1,
 101         BPF_WRITE = 2
 102 };
 103
 104 struct bpf_verifier_ops {
 105         /* return eBPF function prototype for verification */
 106         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 107
 108         /* return true if 'size' wide access at offset 'off' within bpf_context
 109          * with 'type' (read or write) is allowed
 110          */
 111         bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
 112
 113         u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
 114                                   int src_reg, int ctx_off,
 115                                   struct bpf_insn *insn);
 116 };
 117
 118 struct bpf_prog_type_list {
 119         struct list_head list_node;
 120         const struct bpf_verifier_ops *ops;
 121         enum bpf_prog_type type;
 122 };
 123
 124 struct bpf_prog;
 125
 126 struct bpf_prog_aux {
 127         atomic_t refcnt;
 128         u32 used_map_cnt;
 129         const struct bpf_verifier_ops *ops;
 130         struct bpf_map **used_maps;
 131         struct bpf_prog *prog;
 132         union {
 133                 struct work_struct work;
 134                 struct rcu_head rcu;
 135         };
 136 };
 137
 138 struct bpf_array {
 139         struct bpf_map map;
 140         u32 elem_size;
 141         /* 'ownership' of prog_array is claimed by the first program that
 142          * is going to use this map or by the first program which FD is stored
 143          * in the map to make sure that all callers and callees have the same
 144          * prog_type and JITed flag
 145          */
 146         enum bpf_prog_type owner_prog_type;
 147         bool owner_jited;
 148         union {
 149                 char value[0] __aligned(8);
 150                 void *ptrs[0] __aligned(8);
 151         };
 152 };
 153 #define MAX_TAIL_CALL_CNT 32
 154
 155 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
 156 void bpf_fd_array_map_clear(struct bpf_map *map);
 157 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
 158 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
 159
 160 #ifdef CONFIG_BPF_SYSCALL
 161 void bpf_register_prog_type(struct bpf_prog_type_list *tl);
 162 void bpf_register_map_type(struct bpf_map_type_list *tl);
 163
 164 struct bpf_prog *bpf_prog_get(u32 ufd);
 165 void bpf_prog_put(struct bpf_prog *prog);
 166 void bpf_prog_put_rcu(struct bpf_prog *prog);
 167
 168 struct bpf_map *bpf_map_get(struct fd f);
 169 void bpf_map_put(struct bpf_map *map);
 170
 171 /* verify correctness of eBPF program */
 172 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 173 #else
 174 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
 175 {
 176 }
 177
 178 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 179 {
 180         return ERR_PTR(-EOPNOTSUPP);
 181 }
 182
 183 static inline void bpf_prog_put(struct bpf_prog *prog)
 184 {
 185 }
 186 #endif /* CONFIG_BPF_SYSCALL */
 187
 188 /* verifier prototypes for helper functions called from eBPF programs */
 189 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
 190 extern const struct bpf_func_proto bpf_map_update_elem_proto;
 191 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
 192
 193 extern const struct bpf_func_proto bpf_perf_event_read_proto;
 194 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
 195 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
 196 extern const struct bpf_func_proto bpf_tail_call_proto;
 197 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
 198 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
 199 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
 200 extern const struct bpf_func_proto bpf_get_current_comm_proto;
 201 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 202 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 203
 204 #endif /* _LINUX_BPF_H */