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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/perf_event.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 const struct bpf_map_ops *ops;
41 struct work_struct work;
42};
43
44struct bpf_map_type_list {
45 struct list_head list_node;
46 const struct bpf_map_ops *ops;
47 enum bpf_map_type type;
48};
49
50/* function argument constraints */
51enum bpf_arg_type {
52 ARG_DONTCARE = 0, /* unused argument in helper function */
53
54 /* the following constraints used to prototype
55 * bpf_map_lookup/update/delete_elem() functions
56 */
57 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */
58 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */
59 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */
60
61 /* the following constraints used to prototype bpf_memcmp() and other
62 * functions that access data on eBPF program stack
63 */
64 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */
65 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */
66
67 ARG_PTR_TO_CTX, /* pointer to context */
68 ARG_ANYTHING, /* any (initialized) argument is ok */
69};
70
71/* type of values returned from helper functions */
72enum bpf_return_type {
73 RET_INTEGER, /* function returns integer */
74 RET_VOID, /* function doesn't return anything */
75 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
76};
77
78/* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
79 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
80 * instructions after verifying
81 */
82struct bpf_func_proto {
83 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
84 bool gpl_only;
85 enum bpf_return_type ret_type;
86 enum bpf_arg_type arg1_type;
87 enum bpf_arg_type arg2_type;
88 enum bpf_arg_type arg3_type;
89 enum bpf_arg_type arg4_type;
90 enum bpf_arg_type arg5_type;
91};
92
93/* bpf_context is intentionally undefined structure. Pointer to bpf_context is
94 * the first argument to eBPF programs.
95 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
96 */
97struct bpf_context;
98
99enum bpf_access_type {
100 BPF_READ = 1,
101 BPF_WRITE = 2
102};
103
104struct bpf_verifier_ops {
105 /* return eBPF function prototype for verification */
106 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
107
108 /* return true if 'size' wide access at offset 'off' within bpf_context
109 * with 'type' (read or write) is allowed
110 */
111 bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
112
113 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
114 int src_reg, int ctx_off,
115 struct bpf_insn *insn);
116};
117
118struct bpf_prog_type_list {
119 struct list_head list_node;
120 const struct bpf_verifier_ops *ops;
121 enum bpf_prog_type type;
122};
123
124struct bpf_prog;
125
126struct bpf_prog_aux {
127 atomic_t refcnt;
128 u32 used_map_cnt;
129 const struct bpf_verifier_ops *ops;
130 struct bpf_map **used_maps;
131 struct bpf_prog *prog;
132 union {
133 struct work_struct work;
134 struct rcu_head rcu;
135 };
136};
137
138struct bpf_array {
139 struct bpf_map map;
140 u32 elem_size;
141 /* 'ownership' of prog_array is claimed by the first program that
142 * is going to use this map or by the first program which FD is stored
143 * in the map to make sure that all callers and callees have the same
144 * prog_type and JITed flag
145 */
146 enum bpf_prog_type owner_prog_type;
147 bool owner_jited;
148 union {
149 char value[0] __aligned(8);
150 void *ptrs[0] __aligned(8);
151 };
152};
153#define MAX_TAIL_CALL_CNT 32
154
155u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
156void bpf_fd_array_map_clear(struct bpf_map *map);
157bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
158const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
159
160#ifdef CONFIG_BPF_SYSCALL
161void bpf_register_prog_type(struct bpf_prog_type_list *tl);
162void bpf_register_map_type(struct bpf_map_type_list *tl);
163
164struct bpf_prog *bpf_prog_get(u32 ufd);
165void bpf_prog_put(struct bpf_prog *prog);
166void bpf_prog_put_rcu(struct bpf_prog *prog);
167
168struct bpf_map *bpf_map_get(struct fd f);
169void bpf_map_put(struct bpf_map *map);
170
171/* verify correctness of eBPF program */
172int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
173#else
174static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
175{
176}
177
178static inline struct bpf_prog *bpf_prog_get(u32 ufd)
179{
180 return ERR_PTR(-EOPNOTSUPP);
181}
182
183static inline void bpf_prog_put(struct bpf_prog *prog)
184{
185}
186#endif /* CONFIG_BPF_SYSCALL */
187
188/* verifier prototypes for helper functions called from eBPF programs */
189extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
190extern const struct bpf_func_proto bpf_map_update_elem_proto;
191extern const struct bpf_func_proto bpf_map_delete_elem_proto;
192
193extern const struct bpf_func_proto bpf_perf_event_read_proto;
194extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
195extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
196extern const struct bpf_func_proto bpf_tail_call_proto;
197extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
198extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
199extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
200extern const struct bpf_func_proto bpf_get_current_comm_proto;
201extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
202extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
203
204#endif /* _LINUX_BPF_H */