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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
114struct bpf_prog;
115
116struct bpf_verifier_ops {
117 /* return eBPF function prototype for verification */
118 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
119
120 /* return true if 'size' wide access at offset 'off' within bpf_context
121 * with 'type' (read or write) is allowed
122 */
123 bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
124
125 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
126 int src_reg, int ctx_off,
127 struct bpf_insn *insn, struct bpf_prog *prog);
128};
129
130struct bpf_prog_type_list {
131 struct list_head list_node;
132 const struct bpf_verifier_ops *ops;
133 enum bpf_prog_type type;
134};
135
136struct bpf_prog_aux {
137 atomic_t refcnt;
138 u32 used_map_cnt;
139 u32 max_ctx_offset;
140 const struct bpf_verifier_ops *ops;
141 struct bpf_map **used_maps;
142 struct bpf_prog *prog;
143 struct user_struct *user;
144 union {
145 struct work_struct work;
146 struct rcu_head rcu;
147 };
148};
149
150struct bpf_array {
151 struct bpf_map map;
152 u32 elem_size;
153 /* 'ownership' of prog_array is claimed by the first program that
154 * is going to use this map or by the first program which FD is stored
155 * in the map to make sure that all callers and callees have the same
156 * prog_type and JITed flag
157 */
158 enum bpf_prog_type owner_prog_type;
159 bool owner_jited;
160 union {
161 char value[0] __aligned(8);
162 void *ptrs[0] __aligned(8);
163 void __percpu *pptrs[0] __aligned(8);
164 };
165};
166#define MAX_TAIL_CALL_CNT 32
167
168u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
169u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
170void bpf_fd_array_map_clear(struct bpf_map *map);
171bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
172
173const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
174const struct bpf_func_proto *bpf_get_event_output_proto(void);
175
176#ifdef CONFIG_BPF_SYSCALL
177DECLARE_PER_CPU(int, bpf_prog_active);
178
179void bpf_register_prog_type(struct bpf_prog_type_list *tl);
180void bpf_register_map_type(struct bpf_map_type_list *tl);
181
182struct bpf_prog *bpf_prog_get(u32 ufd);
183struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
184void bpf_prog_put(struct bpf_prog *prog);
185void bpf_prog_put_rcu(struct bpf_prog *prog);
186
187struct bpf_map *bpf_map_get_with_uref(u32 ufd);
188struct bpf_map *__bpf_map_get(struct fd f);
189struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
190void bpf_map_put_with_uref(struct bpf_map *map);
191void bpf_map_put(struct bpf_map *map);
192int bpf_map_precharge_memlock(u32 pages);
193
194extern int sysctl_unprivileged_bpf_disabled;
195
196int bpf_map_new_fd(struct bpf_map *map);
197int bpf_prog_new_fd(struct bpf_prog *prog);
198
199int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
200int bpf_obj_get_user(const char __user *pathname);
201
202int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
203int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
204int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
205 u64 flags);
206int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
207 u64 flags);
208int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value);
209
210/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
211 * forced to use 'long' read/writes to try to atomically copy long counters.
212 * Best-effort only. No barriers here, since it _will_ race with concurrent
213 * updates from BPF programs. Called from bpf syscall and mostly used with
214 * size 8 or 16 bytes, so ask compiler to inline it.
215 */
216static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
217{
218 const long *lsrc = src;
219 long *ldst = dst;
220
221 size /= sizeof(long);
222 while (size--)
223 *ldst++ = *lsrc++;
224}
225
226/* verify correctness of eBPF program */
227int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
228#else
229static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
230{
231}
232
233static inline struct bpf_prog *bpf_prog_get(u32 ufd)
234{
235 return ERR_PTR(-EOPNOTSUPP);
236}
237
238static inline void bpf_prog_put(struct bpf_prog *prog)
239{
240}
241#endif /* CONFIG_BPF_SYSCALL */
242
243/* verifier prototypes for helper functions called from eBPF programs */
244extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
245extern const struct bpf_func_proto bpf_map_update_elem_proto;
246extern const struct bpf_func_proto bpf_map_delete_elem_proto;
247
248extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
249extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
250extern const struct bpf_func_proto bpf_tail_call_proto;
251extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
252extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
253extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
254extern const struct bpf_func_proto bpf_get_current_comm_proto;
255extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
256extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
257extern const struct bpf_func_proto bpf_get_stackid_proto;
258
259/* Shared helpers among cBPF and eBPF. */
260void bpf_user_rnd_init_once(void);
261u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
262
263#endif /* _LINUX_BPF_H */