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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
14struct bpf_map;
15
16/* map is generic key/value storage optionally accesible by eBPF programs */
17struct 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
29struct 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
39struct bpf_map_type_list {
40 struct list_head list_node;
41 struct bpf_map_ops *ops;
42 enum bpf_map_type type;
43};
44
45void bpf_register_map_type(struct bpf_map_type_list *tl);
46void bpf_map_put(struct bpf_map *map);
47struct bpf_map *bpf_map_get(struct fd f);
48
49/* function argument constraints */
50enum 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 */
68enum 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 */
78struct 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 */
93struct bpf_context;
94
95enum bpf_access_type {
96 BPF_READ = 1,
97 BPF_WRITE = 2
98};
99
100struct 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
110struct bpf_prog_type_list {
111 struct list_head list_node;
112 struct bpf_verifier_ops *ops;
113 enum bpf_prog_type type;
114};
115
116void bpf_register_prog_type(struct bpf_prog_type_list *tl);
117
118struct bpf_prog;
119
120struct 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
132void bpf_prog_put(struct bpf_prog *prog);
133#else
134static inline void bpf_prog_put(struct bpf_prog *prog) {}
135#endif
136struct bpf_prog *bpf_prog_get(u32 ufd);
137/* verify correctness of eBPF program */
138int bpf_check(struct bpf_prog *fp, union bpf_attr *attr);
139
140/* verifier prototypes for helper functions called from eBPF programs */
141extern struct bpf_func_proto bpf_map_lookup_elem_proto;
142extern struct bpf_func_proto bpf_map_update_elem_proto;
143extern struct bpf_func_proto bpf_map_delete_elem_proto;
144
145#endif /* _LINUX_BPF_H */