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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_PTR_TO_RAW_STACK, /* any pointer to eBPF program stack, area does not
70 * need to be initialized, helper function must fill
71 * all bytes or clear them in error case.
72 */
73
74 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */
75 ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack or 0 */
76
77 ARG_PTR_TO_CTX, /* pointer to context */
78 ARG_ANYTHING, /* any (initialized) argument is ok */
79};
80
81/* type of values returned from helper functions */
82enum bpf_return_type {
83 RET_INTEGER, /* function returns integer */
84 RET_VOID, /* function doesn't return anything */
85 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
86};
87
88/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
89 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
90 * instructions after verifying
91 */
92struct bpf_func_proto {
93 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
94 bool gpl_only;
95 enum bpf_return_type ret_type;
96 enum bpf_arg_type arg1_type;
97 enum bpf_arg_type arg2_type;
98 enum bpf_arg_type arg3_type;
99 enum bpf_arg_type arg4_type;
100 enum bpf_arg_type arg5_type;
101};
102
103/* bpf_context is intentionally undefined structure. Pointer to bpf_context is
104 * the first argument to eBPF programs.
105 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
106 */
107struct bpf_context;
108
109enum bpf_access_type {
110 BPF_READ = 1,
111 BPF_WRITE = 2
112};
113
114/* types of values stored in eBPF registers */
115enum bpf_reg_type {
116 NOT_INIT = 0, /* nothing was written into register */
117 UNKNOWN_VALUE, /* reg doesn't contain a valid pointer */
118 PTR_TO_CTX, /* reg points to bpf_context */
119 CONST_PTR_TO_MAP, /* reg points to struct bpf_map */
120 PTR_TO_MAP_VALUE, /* reg points to map element value */
121 PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
122 FRAME_PTR, /* reg == frame_pointer */
123 PTR_TO_STACK, /* reg == frame_pointer + imm */
124 CONST_IMM, /* constant integer value */
125
126 /* PTR_TO_PACKET represents:
127 * skb->data
128 * skb->data + imm
129 * skb->data + (u16) var
130 * skb->data + (u16) var + imm
131 * if (range > 0) then [ptr, ptr + range - off) is safe to access
132 * if (id > 0) means that some 'var' was added
133 * if (off > 0) menas that 'imm' was added
134 */
135 PTR_TO_PACKET,
136 PTR_TO_PACKET_END, /* skb->data + headlen */
137};
138
139struct bpf_prog;
140
141struct bpf_verifier_ops {
142 /* return eBPF function prototype for verification */
143 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
144
145 /* return true if 'size' wide access at offset 'off' within bpf_context
146 * with 'type' (read or write) is allowed
147 */
148 bool (*is_valid_access)(int off, int size, enum bpf_access_type type,
149 enum bpf_reg_type *reg_type);
150
151 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
152 int src_reg, int ctx_off,
153 struct bpf_insn *insn, struct bpf_prog *prog);
154};
155
156struct bpf_prog_type_list {
157 struct list_head list_node;
158 const struct bpf_verifier_ops *ops;
159 enum bpf_prog_type type;
160};
161
162struct bpf_prog_aux {
163 atomic_t refcnt;
164 u32 used_map_cnt;
165 u32 max_ctx_offset;
166 const struct bpf_verifier_ops *ops;
167 struct bpf_map **used_maps;
168 struct bpf_prog *prog;
169 struct user_struct *user;
170 union {
171 struct work_struct work;
172 struct rcu_head rcu;
173 };
174};
175
176struct bpf_array {
177 struct bpf_map map;
178 u32 elem_size;
179 /* 'ownership' of prog_array is claimed by the first program that
180 * is going to use this map or by the first program which FD is stored
181 * in the map to make sure that all callers and callees have the same
182 * prog_type and JITed flag
183 */
184 enum bpf_prog_type owner_prog_type;
185 bool owner_jited;
186 union {
187 char value[0] __aligned(8);
188 void *ptrs[0] __aligned(8);
189 void __percpu *pptrs[0] __aligned(8);
190 };
191};
192#define MAX_TAIL_CALL_CNT 32
193
194u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
195u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
196void bpf_fd_array_map_clear(struct bpf_map *map);
197bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
198
199const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
200const struct bpf_func_proto *bpf_get_event_output_proto(void);
201
202#ifdef CONFIG_BPF_SYSCALL
203DECLARE_PER_CPU(int, bpf_prog_active);
204
205void bpf_register_prog_type(struct bpf_prog_type_list *tl);
206void bpf_register_map_type(struct bpf_map_type_list *tl);
207
208struct bpf_prog *bpf_prog_get(u32 ufd);
209struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
210void bpf_prog_put(struct bpf_prog *prog);
211void bpf_prog_put_rcu(struct bpf_prog *prog);
212
213struct bpf_map *bpf_map_get_with_uref(u32 ufd);
214struct bpf_map *__bpf_map_get(struct fd f);
215struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
216void bpf_map_put_with_uref(struct bpf_map *map);
217void bpf_map_put(struct bpf_map *map);
218int bpf_map_precharge_memlock(u32 pages);
219
220extern int sysctl_unprivileged_bpf_disabled;
221
222int bpf_map_new_fd(struct bpf_map *map);
223int bpf_prog_new_fd(struct bpf_prog *prog);
224
225int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
226int bpf_obj_get_user(const char __user *pathname);
227
228int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
229int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
230int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
231 u64 flags);
232int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
233 u64 flags);
234int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);
235
236/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
237 * forced to use 'long' read/writes to try to atomically copy long counters.
238 * Best-effort only. No barriers here, since it _will_ race with concurrent
239 * updates from BPF programs. Called from bpf syscall and mostly used with
240 * size 8 or 16 bytes, so ask compiler to inline it.
241 */
242static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
243{
244 const long *lsrc = src;
245 long *ldst = dst;
246
247 size /= sizeof(long);
248 while (size--)
249 *ldst++ = *lsrc++;
250}
251
252/* verify correctness of eBPF program */
253int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
254#else
255static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
256{
257}
258
259static inline struct bpf_prog *bpf_prog_get(u32 ufd)
260{
261 return ERR_PTR(-EOPNOTSUPP);
262}
263
264static inline void bpf_prog_put(struct bpf_prog *prog)
265{
266}
267
268static inline void bpf_prog_put_rcu(struct bpf_prog *prog)
269{
270}
271#endif /* CONFIG_BPF_SYSCALL */
272
273/* verifier prototypes for helper functions called from eBPF programs */
274extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
275extern const struct bpf_func_proto bpf_map_update_elem_proto;
276extern const struct bpf_func_proto bpf_map_delete_elem_proto;
277
278extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
279extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
280extern const struct bpf_func_proto bpf_tail_call_proto;
281extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
282extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
283extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
284extern const struct bpf_func_proto bpf_get_current_comm_proto;
285extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
286extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
287extern const struct bpf_func_proto bpf_get_stackid_proto;
288
289/* Shared helpers among cBPF and eBPF. */
290void bpf_user_rnd_init_once(void);
291u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
292
293#endif /* _LINUX_BPF_H */