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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#include <linux/percpu.h>
14
15struct bpf_map;
16
17/* map is generic key/value storage optionally accesible by eBPF programs */
18struct 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
34struct 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
48struct 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 */
55enum 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 */
77enum 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 */
87struct 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 */
102struct bpf_context;
103
104enum bpf_access_type {
105 BPF_READ = 1,
106 BPF_WRITE = 2
107};
108
109struct bpf_prog;
110
111struct 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
125struct 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
131struct 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
144struct 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
162u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
163void bpf_fd_array_map_clear(struct bpf_map *map);
164bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
165const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
166
167#ifdef CONFIG_BPF_SYSCALL
168DECLARE_PER_CPU(int, bpf_prog_active);
169
170void bpf_register_prog_type(struct bpf_prog_type_list *tl);
171void bpf_register_map_type(struct bpf_map_type_list *tl);
172
173struct bpf_prog *bpf_prog_get(u32 ufd);
174struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
175void bpf_prog_put(struct bpf_prog *prog);
176void bpf_prog_put_rcu(struct bpf_prog *prog);
177
178struct bpf_map *bpf_map_get_with_uref(u32 ufd);
179struct bpf_map *__bpf_map_get(struct fd f);
180struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
181void bpf_map_put_with_uref(struct bpf_map *map);
182void bpf_map_put(struct bpf_map *map);
183int bpf_map_precharge_memlock(u32 pages);
184
185extern int sysctl_unprivileged_bpf_disabled;
186
187int bpf_map_new_fd(struct bpf_map *map);
188int bpf_prog_new_fd(struct bpf_prog *prog);
189
190int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
191int bpf_obj_get_user(const char __user *pathname);
192
193int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
194int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
195int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
196 u64 flags);
197int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
198 u64 flags);
199int 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 */
207static 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 */
218int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
219#else
220static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
221{
222}
223
224static inline struct bpf_prog *bpf_prog_get(u32 ufd)
225{
226 return ERR_PTR(-EOPNOTSUPP);
227}
228
229static 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 */
235extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
236extern const struct bpf_func_proto bpf_map_update_elem_proto;
237extern const struct bpf_func_proto bpf_map_delete_elem_proto;
238
239extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
240extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
241extern const struct bpf_func_proto bpf_tail_call_proto;
242extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
243extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
244extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
245extern const struct bpf_func_proto bpf_get_current_comm_proto;
246extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
247extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
248extern const struct bpf_func_proto bpf_get_stackid_proto;
249
250/* Shared helpers among cBPF and eBPF. */
251void bpf_user_rnd_init_once(void);
252u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
253
254#endif /* _LINUX_BPF_H */