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 #include <linux/err.h> 15 16 struct perf_event; 17 struct bpf_map; 18 19 /* map is generic key/value storage optionally accesible by eBPF programs */ 20 struct bpf_map_ops { 21 /* funcs callable from userspace (via syscall) */ 22 struct bpf_map *(*map_alloc)(union bpf_attr *attr); 23 void (*map_release)(struct bpf_map *map, struct file *map_file); 24 void (*map_free)(struct bpf_map *map); 25 int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key); 26 27 /* funcs callable from userspace and from eBPF programs */ 28 void *(*map_lookup_elem)(struct bpf_map *map, void *key); 29 int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); 30 int (*map_delete_elem)(struct bpf_map *map, void *key); 31 32 /* funcs called by prog_array and perf_event_array map */ 33 void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, 34 int fd); 35 void (*map_fd_put_ptr)(void *ptr); 36 }; 37 38 struct bpf_map { 39 atomic_t refcnt; 40 enum bpf_map_type map_type; 41 u32 key_size; 42 u32 value_size; 43 u32 max_entries; 44 u32 map_flags; 45 u32 pages; 46 struct user_struct *user; 47 const struct bpf_map_ops *ops; 48 struct work_struct work; 49 atomic_t usercnt; 50 }; 51 52 struct bpf_map_type_list { 53 struct list_head list_node; 54 const struct bpf_map_ops *ops; 55 enum bpf_map_type type; 56 }; 57 58 /* function argument constraints */ 59 enum bpf_arg_type { 60 ARG_DONTCARE = 0, /* unused argument in helper function */ 61 62 /* the following constraints used to prototype 63 * bpf_map_lookup/update/delete_elem() functions 64 */ 65 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ 66 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ 67 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ 68 69 /* the following constraints used to prototype bpf_memcmp() and other 70 * functions that access data on eBPF program stack 71 */ 72 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */ 73 ARG_PTR_TO_RAW_STACK, /* any pointer to eBPF program stack, area does not 74 * need to be initialized, helper function must fill 75 * all bytes or clear them in error case. 76 */ 77 78 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */ 79 ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack or 0 */ 80 81 ARG_PTR_TO_CTX, /* pointer to context */ 82 ARG_ANYTHING, /* any (initialized) argument is ok */ 83 }; 84 85 /* type of values returned from helper functions */ 86 enum bpf_return_type { 87 RET_INTEGER, /* function returns integer */ 88 RET_VOID, /* function doesn't return anything */ 89 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 90 }; 91 92 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 93 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 94 * instructions after verifying 95 */ 96 struct bpf_func_proto { 97 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 98 bool gpl_only; 99 bool pkt_access; 100 enum bpf_return_type ret_type; 101 enum bpf_arg_type arg1_type; 102 enum bpf_arg_type arg2_type; 103 enum bpf_arg_type arg3_type; 104 enum bpf_arg_type arg4_type; 105 enum bpf_arg_type arg5_type; 106 }; 107 108 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 109 * the first argument to eBPF programs. 110 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 111 */ 112 struct bpf_context; 113 114 enum bpf_access_type { 115 BPF_READ = 1, 116 BPF_WRITE = 2 117 }; 118 119 /* types of values stored in eBPF registers */ 120 enum bpf_reg_type { 121 NOT_INIT = 0, /* nothing was written into register */ 122 UNKNOWN_VALUE, /* reg doesn't contain a valid pointer */ 123 PTR_TO_CTX, /* reg points to bpf_context */ 124 CONST_PTR_TO_MAP, /* reg points to struct bpf_map */ 125 PTR_TO_MAP_VALUE, /* reg points to map element value */ 126 PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */ 127 FRAME_PTR, /* reg == frame_pointer */ 128 PTR_TO_STACK, /* reg == frame_pointer + imm */ 129 CONST_IMM, /* constant integer value */ 130 131 /* PTR_TO_PACKET represents: 132 * skb->data 133 * skb->data + imm 134 * skb->data + (u16) var 135 * skb->data + (u16) var + imm 136 * if (range > 0) then [ptr, ptr + range - off) is safe to access 137 * if (id > 0) means that some 'var' was added 138 * if (off > 0) menas that 'imm' was added 139 */ 140 PTR_TO_PACKET, 141 PTR_TO_PACKET_END, /* skb->data + headlen */ 142 143 /* PTR_TO_MAP_VALUE_ADJ is used for doing pointer math inside of a map 144 * elem value. We only allow this if we can statically verify that 145 * access from this register are going to fall within the size of the 146 * map element. 147 */ 148 PTR_TO_MAP_VALUE_ADJ, 149 }; 150 151 struct bpf_prog; 152 153 struct bpf_verifier_ops { 154 /* return eBPF function prototype for verification */ 155 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 156 157 /* return true if 'size' wide access at offset 'off' within bpf_context 158 * with 'type' (read or write) is allowed 159 */ 160 bool (*is_valid_access)(int off, int size, enum bpf_access_type type, 161 enum bpf_reg_type *reg_type); 162 int (*gen_prologue)(struct bpf_insn *insn, bool direct_write, 163 const struct bpf_prog *prog); 164 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 165 int src_reg, int ctx_off, 166 struct bpf_insn *insn, struct bpf_prog *prog); 167 }; 168 169 struct bpf_prog_type_list { 170 struct list_head list_node; 171 const struct bpf_verifier_ops *ops; 172 enum bpf_prog_type type; 173 }; 174 175 struct bpf_prog_aux { 176 atomic_t refcnt; 177 u32 used_map_cnt; 178 u32 max_ctx_offset; 179 const struct bpf_verifier_ops *ops; 180 struct bpf_map **used_maps; 181 struct bpf_prog *prog; 182 struct user_struct *user; 183 union { 184 struct work_struct work; 185 struct rcu_head rcu; 186 }; 187 }; 188 189 struct bpf_array { 190 struct bpf_map map; 191 u32 elem_size; 192 /* 'ownership' of prog_array is claimed by the first program that 193 * is going to use this map or by the first program which FD is stored 194 * in the map to make sure that all callers and callees have the same 195 * prog_type and JITed flag 196 */ 197 enum bpf_prog_type owner_prog_type; 198 bool owner_jited; 199 union { 200 char value[0] __aligned(8); 201 void *ptrs[0] __aligned(8); 202 void __percpu *pptrs[0] __aligned(8); 203 }; 204 }; 205 206 #define MAX_TAIL_CALL_CNT 32 207 208 struct bpf_event_entry { 209 struct perf_event *event; 210 struct file *perf_file; 211 struct file *map_file; 212 struct rcu_head rcu; 213 }; 214 215 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 216 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 217 218 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 219 220 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 221 222 typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, 223 unsigned long off, unsigned long len); 224 225 u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 226 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy); 227 228 #ifdef CONFIG_BPF_SYSCALL 229 DECLARE_PER_CPU(int, bpf_prog_active); 230 231 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 232 void bpf_register_map_type(struct bpf_map_type_list *tl); 233 234 struct bpf_prog *bpf_prog_get(u32 ufd); 235 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type); 236 struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i); 237 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); 238 void bpf_prog_put(struct bpf_prog *prog); 239 240 struct bpf_map *bpf_map_get_with_uref(u32 ufd); 241 struct bpf_map *__bpf_map_get(struct fd f); 242 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref); 243 void bpf_map_put_with_uref(struct bpf_map *map); 244 void bpf_map_put(struct bpf_map *map); 245 int bpf_map_precharge_memlock(u32 pages); 246 247 extern int sysctl_unprivileged_bpf_disabled; 248 249 int bpf_map_new_fd(struct bpf_map *map); 250 int bpf_prog_new_fd(struct bpf_prog *prog); 251 252 int bpf_obj_pin_user(u32 ufd, const char __user *pathname); 253 int bpf_obj_get_user(const char __user *pathname); 254 255 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); 256 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); 257 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, 258 u64 flags); 259 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, 260 u64 flags); 261 262 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value); 263 264 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file, 265 void *key, void *value, u64 map_flags); 266 void bpf_fd_array_map_clear(struct bpf_map *map); 267 268 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and 269 * forced to use 'long' read/writes to try to atomically copy long counters. 270 * Best-effort only. No barriers here, since it _will_ race with concurrent 271 * updates from BPF programs. Called from bpf syscall and mostly used with 272 * size 8 or 16 bytes, so ask compiler to inline it. 273 */ 274 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size) 275 { 276 const long *lsrc = src; 277 long *ldst = dst; 278 279 size /= sizeof(long); 280 while (size--) 281 *ldst++ = *lsrc++; 282 } 283 284 /* verify correctness of eBPF program */ 285 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 286 #else 287 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 288 { 289 } 290 291 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 292 { 293 return ERR_PTR(-EOPNOTSUPP); 294 } 295 296 static inline struct bpf_prog *bpf_prog_get_type(u32 ufd, 297 enum bpf_prog_type type) 298 { 299 return ERR_PTR(-EOPNOTSUPP); 300 } 301 static inline struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) 302 { 303 return ERR_PTR(-EOPNOTSUPP); 304 } 305 306 static inline void bpf_prog_put(struct bpf_prog *prog) 307 { 308 } 309 static inline struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) 310 { 311 return ERR_PTR(-EOPNOTSUPP); 312 } 313 #endif /* CONFIG_BPF_SYSCALL */ 314 315 /* verifier prototypes for helper functions called from eBPF programs */ 316 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 317 extern const struct bpf_func_proto bpf_map_update_elem_proto; 318 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 319 320 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 321 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 322 extern const struct bpf_func_proto bpf_tail_call_proto; 323 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 324 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 325 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 326 extern const struct bpf_func_proto bpf_get_current_comm_proto; 327 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 328 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 329 extern const struct bpf_func_proto bpf_get_stackid_proto; 330 331 /* Shared helpers among cBPF and eBPF. */ 332 void bpf_user_rnd_init_once(void); 333 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 334 335 #endif /* _LINUX_BPF_H */ 336