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
  14 struct bpf_map;
  15
  16 /* map is generic key/value storage optionally accesible by eBPF programs */
  17 struct bpf_map_ops {
  18         /* funcs callable from userspace (via syscall) */
  19         struct bpf_map *(*map_alloc)(union bpf_attr *attr);
  20         void (*map_free)(struct bpf_map *);
  21         int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key);
  22
  23         /* funcs callable from userspace and from eBPF programs */
  24         void *(*map_lookup_elem)(struct bpf_map *map, void *key);
  25         int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags);
  26         int (*map_delete_elem)(struct bpf_map *map, void *key);
  27 };
  28
  29 struct bpf_map {
  30         atomic_t refcnt;
  31         enum bpf_map_type map_type;
  32         u32 key_size;
  33         u32 value_size;
  34         u32 max_entries;
  35         struct bpf_map_ops *ops;
  36         struct work_struct work;
  37 };
  38
  39 struct bpf_map_type_list {
  40         struct list_head list_node;
  41         struct bpf_map_ops *ops;
  42         enum bpf_map_type type;
  43 };
  44
  45 void bpf_register_map_type(struct bpf_map_type_list *tl);
  46 void bpf_map_put(struct bpf_map *map);
  47 struct bpf_map *bpf_map_get(struct fd f);
  48
  49 /* function argument constraints */
  50 enum bpf_arg_type {
  51         ARG_ANYTHING = 0,       /* any argument is ok */
  52
  53         /* the following constraints used to prototype
  54          * bpf_map_lookup/update/delete_elem() functions
  55          */
  56         ARG_CONST_MAP_PTR,      /* const argument used as pointer to bpf_map */
  57         ARG_PTR_TO_MAP_KEY,     /* pointer to stack used as map key */
  58         ARG_PTR_TO_MAP_VALUE,   /* pointer to stack used as map value */
  59
  60         /* the following constraints used to prototype bpf_memcmp() and other
  61          * functions that access data on eBPF program stack
  62          */
  63         ARG_PTR_TO_STACK,       /* any pointer to eBPF program stack */
  64         ARG_CONST_STACK_SIZE,   /* number of bytes accessed from stack */
  65 };
  66
  67 /* type of values returned from helper functions */
  68 enum bpf_return_type {
  69         RET_INTEGER,                    /* function returns integer */
  70         RET_VOID,                       /* function doesn't return anything */
  71         RET_PTR_TO_MAP_VALUE_OR_NULL,   /* returns a pointer to map elem value or NULL */
  72 };
  73
  74 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
  75  * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
  76  * instructions after verifying
  77  */
  78 struct bpf_func_proto {
  79         u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
  80         bool gpl_only;
  81         enum bpf_return_type ret_type;
  82         enum bpf_arg_type arg1_type;
  83         enum bpf_arg_type arg2_type;
  84         enum bpf_arg_type arg3_type;
  85         enum bpf_arg_type arg4_type;
  86         enum bpf_arg_type arg5_type;
  87 };
  88
  89 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
  90  * the first argument to eBPF programs.
  91  * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
  92  */
  93 struct bpf_context;
  94
  95 enum bpf_access_type {
  96         BPF_READ = 1,
  97         BPF_WRITE = 2
  98 };
  99
 100 struct bpf_verifier_ops {
 101         /* return eBPF function prototype for verification */
 102         const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
 103
 104         /* return true if 'size' wide access at offset 'off' within bpf_context
 105          * with 'type' (read or write) is allowed
 106          */
 107         bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
 108 };
 109
 110 struct bpf_prog_type_list {
 111         struct list_head list_node;
 112         struct bpf_verifier_ops *ops;
 113         enum bpf_prog_type type;
 114 };
 115
 116 void bpf_register_prog_type(struct bpf_prog_type_list *tl);
 117
 118 struct bpf_prog;
 119
 120 struct bpf_prog_aux {
 121         atomic_t refcnt;
 122         bool is_gpl_compatible;
 123         enum bpf_prog_type prog_type;
 124         struct bpf_verifier_ops *ops;
 125         struct bpf_map **used_maps;
 126         u32 used_map_cnt;
 127         struct bpf_prog *prog;
 128         struct work_struct work;
 129 };
 130
 131 #ifdef CONFIG_BPF_SYSCALL
 132 void bpf_prog_put(struct bpf_prog *prog);
 133 #else
 134 static inline void bpf_prog_put(struct bpf_prog *prog) {}
 135 #endif
 136 struct bpf_prog *bpf_prog_get(u32 ufd);
 137 /* verify correctness of eBPF program */
 138 int bpf_check(struct bpf_prog *fp, union bpf_attr *attr);
 139
 140 /* verifier prototypes for helper functions called from eBPF programs */
 141 extern struct bpf_func_proto bpf_map_lookup_elem_proto;
 142 extern struct bpf_func_proto bpf_map_update_elem_proto;
 143 extern struct bpf_func_proto bpf_map_delete_elem_proto;
 144
 145 #endif /* _LINUX_BPF_H */