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
14 struct bpf_map;
15
16 /* map is generic key/value storage optionally accesible by eBPF programs */
17 struct 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 /* funcs called by prog_array and perf_event_array map */
29 void *(*map_fd_get_ptr) (struct bpf_map *map, int fd);
30 void (*map_fd_put_ptr) (void *ptr);
31 };
32
33 struct bpf_map {
34 atomic_t refcnt;
35 enum bpf_map_type map_type;
36 u32 key_size;
37 u32 value_size;
38 u32 max_entries;
39 u32 pages;
40 struct user_struct *user;
41 const struct bpf_map_ops *ops;
42 struct work_struct work;
43 atomic_t usercnt;
44 };
45
46 struct bpf_map_type_list {
47 struct list_head list_node;
48 const struct bpf_map_ops *ops;
49 enum bpf_map_type type;
50 };
51
52 /* function argument constraints */
53 enum bpf_arg_type {
54 ARG_DONTCARE = 0, /* unused argument in helper function */
55
56 /* the following constraints used to prototype
57 * bpf_map_lookup/update/delete_elem() functions
58 */
59 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */
60 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */
61 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */
62
63 /* the following constraints used to prototype bpf_memcmp() and other
64 * functions that access data on eBPF program stack
65 */
66 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */
67 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */
68
69 ARG_PTR_TO_CTX, /* pointer to context */
70 ARG_ANYTHING, /* any (initialized) argument is ok */
71 };
72
73 /* type of values returned from helper functions */
74 enum bpf_return_type {
75 RET_INTEGER, /* function returns integer */
76 RET_VOID, /* function doesn't return anything */
77 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
78 };
79
80 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
81 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL
82 * instructions after verifying
83 */
84 struct bpf_func_proto {
85 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
86 bool gpl_only;
87 enum bpf_return_type ret_type;
88 enum bpf_arg_type arg1_type;
89 enum bpf_arg_type arg2_type;
90 enum bpf_arg_type arg3_type;
91 enum bpf_arg_type arg4_type;
92 enum bpf_arg_type arg5_type;
93 };
94
95 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is
96 * the first argument to eBPF programs.
97 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *'
98 */
99 struct bpf_context;
100
101 enum bpf_access_type {
102 BPF_READ = 1,
103 BPF_WRITE = 2
104 };
105
106 struct bpf_prog;
107
108 struct bpf_verifier_ops {
109 /* return eBPF function prototype for verification */
110 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
111
112 /* return true if 'size' wide access at offset 'off' within bpf_context
113 * with 'type' (read or write) is allowed
114 */
115 bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
116
117 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg,
118 int src_reg, int ctx_off,
119 struct bpf_insn *insn, struct bpf_prog *prog);
120 };
121
122 struct bpf_prog_type_list {
123 struct list_head list_node;
124 const struct bpf_verifier_ops *ops;
125 enum bpf_prog_type type;
126 };
127
128 struct bpf_prog_aux {
129 atomic_t refcnt;
130 u32 used_map_cnt;
131 const struct bpf_verifier_ops *ops;
132 struct bpf_map **used_maps;
133 struct bpf_prog *prog;
134 struct user_struct *user;
135 union {
136 struct work_struct work;
137 struct rcu_head rcu;
138 };
139 };
140
141 struct bpf_array {
142 struct bpf_map map;
143 u32 elem_size;
144 /* 'ownership' of prog_array is claimed by the first program that
145 * is going to use this map or by the first program which FD is stored
146 * in the map to make sure that all callers and callees have the same
147 * prog_type and JITed flag
148 */
149 enum bpf_prog_type owner_prog_type;
150 bool owner_jited;
151 union {
152 char value[0] __aligned(8);
153 void *ptrs[0] __aligned(8);
154 };
155 };
156 #define MAX_TAIL_CALL_CNT 32
157
158 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5);
159 void bpf_fd_array_map_clear(struct bpf_map *map);
160 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp);
161 const struct bpf_func_proto *bpf_get_trace_printk_proto(void);
162
163 #ifdef CONFIG_BPF_SYSCALL
164 void bpf_register_prog_type(struct bpf_prog_type_list *tl);
165 void bpf_register_map_type(struct bpf_map_type_list *tl);
166
167 struct bpf_prog *bpf_prog_get(u32 ufd);
168 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
169 void bpf_prog_put(struct bpf_prog *prog);
170 void bpf_prog_put_rcu(struct bpf_prog *prog);
171
172 struct bpf_map *bpf_map_get_with_uref(u32 ufd);
173 struct bpf_map *__bpf_map_get(struct fd f);
174 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref);
175 void bpf_map_put_with_uref(struct bpf_map *map);
176 void bpf_map_put(struct bpf_map *map);
177
178 extern int sysctl_unprivileged_bpf_disabled;
179
180 int bpf_map_new_fd(struct bpf_map *map);
181 int bpf_prog_new_fd(struct bpf_prog *prog);
182
183 int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
184 int bpf_obj_get_user(const char __user *pathname);
185
186 /* verify correctness of eBPF program */
187 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
188 #else
bpf_register_prog_type(struct bpf_prog_type_list * tl)189 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
190 {
191 }
192
bpf_prog_get(u32 ufd)193 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
194 {
195 return ERR_PTR(-EOPNOTSUPP);
196 }
197
bpf_prog_put(struct bpf_prog * prog)198 static inline void bpf_prog_put(struct bpf_prog *prog)
199 {
200 }
201 #endif /* CONFIG_BPF_SYSCALL */
202
203 /* verifier prototypes for helper functions called from eBPF programs */
204 extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
205 extern const struct bpf_func_proto bpf_map_update_elem_proto;
206 extern const struct bpf_func_proto bpf_map_delete_elem_proto;
207
208 extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
209 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
210 extern const struct bpf_func_proto bpf_tail_call_proto;
211 extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
212 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
213 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
214 extern const struct bpf_func_proto bpf_get_current_comm_proto;
215 extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
216 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
217
218 /* Shared helpers among cBPF and eBPF. */
219 void bpf_user_rnd_init_once(void);
220 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
221
222 #endif /* _LINUX_BPF_H */
223