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 15 struct bpf_map; 16 17 /* map is generic key/value storage optionally accesible by eBPF programs */ 18 struct 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 34 struct 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 48 struct 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 */ 55 enum 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 */ 82 enum 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 */ 92 struct 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 */ 107 struct bpf_context; 108 109 enum bpf_access_type { 110 BPF_READ = 1, 111 BPF_WRITE = 2 112 }; 113 114 /* types of values stored in eBPF registers */ 115 enum 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 }; 138 139 struct bpf_prog; 140 141 struct 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 }; 155 156 struct bpf_prog_type_list { 157 struct list_head list_node; 158 const struct bpf_verifier_ops *ops; 159 enum bpf_prog_type type; 160 }; 161 162 struct 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 }; 175 176 struct 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 32 193 194 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 195 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 196 void bpf_fd_array_map_clear(struct bpf_map *map); 197 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 198 199 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 200 const struct bpf_func_proto *bpf_get_event_output_proto(void); 201 202 #ifdef CONFIG_BPF_SYSCALL 203 DECLARE_PER_CPU(int, bpf_prog_active); 204 205 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 206 void bpf_register_map_type(struct bpf_map_type_list *tl); 207 208 struct bpf_prog *bpf_prog_get(u32 ufd); 209 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); 210 void bpf_prog_put(struct bpf_prog *prog); 211 void bpf_prog_put_rcu(struct bpf_prog *prog); 212 213 struct bpf_map *bpf_map_get_with_uref(u32 ufd); 214 struct bpf_map *__bpf_map_get(struct fd f); 215 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref); 216 void bpf_map_put_with_uref(struct bpf_map *map); 217 void bpf_map_put(struct bpf_map *map); 218 int bpf_map_precharge_memlock(u32 pages); 219 220 extern int sysctl_unprivileged_bpf_disabled; 221 222 int bpf_map_new_fd(struct bpf_map *map); 223 int bpf_prog_new_fd(struct bpf_prog *prog); 224 225 int bpf_obj_pin_user(u32 ufd, const char __user *pathname); 226 int bpf_obj_get_user(const char __user *pathname); 227 228 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); 229 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); 230 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, 231 u64 flags); 232 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, 233 u64 flags); 234 int 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 */ 242 static 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 */ 253 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 254 #else 255 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 256 { 257 } 258 259 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 260 { 261 return ERR_PTR(-EOPNOTSUPP); 262 } 263 264 static inline void bpf_prog_put(struct bpf_prog *prog) 265 { 266 } 267 268 static 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 */ 274 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 275 extern const struct bpf_func_proto bpf_map_update_elem_proto; 276 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 277 278 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 279 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 280 extern const struct bpf_func_proto bpf_tail_call_proto; 281 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 282 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 283 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 284 extern const struct bpf_func_proto bpf_get_current_comm_proto; 285 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 286 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 287 extern const struct bpf_func_proto bpf_get_stackid_proto; 288 289 /* Shared helpers among cBPF and eBPF. */ 290 void bpf_user_rnd_init_once(void); 291 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 292 293 #endif /* _LINUX_BPF_H */ 294