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 bpf_map; 17 18 /* map is generic key/value storage optionally accesible by eBPF programs */ 19 struct bpf_map_ops { 20 /* funcs callable from userspace (via syscall) */ 21 struct bpf_map *(*map_alloc)(union bpf_attr *attr); 22 void (*map_free)(struct bpf_map *); 23 int (*map_get_next_key)(struct bpf_map *map, void *key, void *next_key); 24 25 /* funcs callable from userspace and from eBPF programs */ 26 void *(*map_lookup_elem)(struct bpf_map *map, void *key); 27 int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); 28 int (*map_delete_elem)(struct bpf_map *map, void *key); 29 30 /* funcs called by prog_array and perf_event_array map */ 31 void *(*map_fd_get_ptr) (struct bpf_map *map, int fd); 32 void (*map_fd_put_ptr) (void *ptr); 33 }; 34 35 struct bpf_map { 36 atomic_t refcnt; 37 enum bpf_map_type map_type; 38 u32 key_size; 39 u32 value_size; 40 u32 max_entries; 41 u32 map_flags; 42 u32 pages; 43 struct user_struct *user; 44 const struct bpf_map_ops *ops; 45 struct work_struct work; 46 atomic_t usercnt; 47 }; 48 49 struct bpf_map_type_list { 50 struct list_head list_node; 51 const struct bpf_map_ops *ops; 52 enum bpf_map_type type; 53 }; 54 55 /* function argument constraints */ 56 enum bpf_arg_type { 57 ARG_DONTCARE = 0, /* unused argument in helper function */ 58 59 /* the following constraints used to prototype 60 * bpf_map_lookup/update/delete_elem() functions 61 */ 62 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ 63 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ 64 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ 65 66 /* the following constraints used to prototype bpf_memcmp() and other 67 * functions that access data on eBPF program stack 68 */ 69 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */ 70 ARG_PTR_TO_RAW_STACK, /* any pointer to eBPF program stack, area does not 71 * need to be initialized, helper function must fill 72 * all bytes or clear them in error case. 73 */ 74 75 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */ 76 ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack or 0 */ 77 78 ARG_PTR_TO_CTX, /* pointer to context */ 79 ARG_ANYTHING, /* any (initialized) argument is ok */ 80 }; 81 82 /* type of values returned from helper functions */ 83 enum bpf_return_type { 84 RET_INTEGER, /* function returns integer */ 85 RET_VOID, /* function doesn't return anything */ 86 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 87 }; 88 89 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 90 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 91 * instructions after verifying 92 */ 93 struct bpf_func_proto { 94 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 95 bool gpl_only; 96 enum bpf_return_type ret_type; 97 enum bpf_arg_type arg1_type; 98 enum bpf_arg_type arg2_type; 99 enum bpf_arg_type arg3_type; 100 enum bpf_arg_type arg4_type; 101 enum bpf_arg_type arg5_type; 102 }; 103 104 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 105 * the first argument to eBPF programs. 106 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 107 */ 108 struct bpf_context; 109 110 enum bpf_access_type { 111 BPF_READ = 1, 112 BPF_WRITE = 2 113 }; 114 115 struct bpf_prog; 116 117 struct bpf_verifier_ops { 118 /* return eBPF function prototype for verification */ 119 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 120 121 /* return true if 'size' wide access at offset 'off' within bpf_context 122 * with 'type' (read or write) is allowed 123 */ 124 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 125 126 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 127 int src_reg, int ctx_off, 128 struct bpf_insn *insn, struct bpf_prog *prog); 129 }; 130 131 struct bpf_prog_type_list { 132 struct list_head list_node; 133 const struct bpf_verifier_ops *ops; 134 enum bpf_prog_type type; 135 }; 136 137 struct bpf_prog_aux { 138 atomic_t refcnt; 139 u32 used_map_cnt; 140 u32 max_ctx_offset; 141 const struct bpf_verifier_ops *ops; 142 struct bpf_map **used_maps; 143 struct bpf_prog *prog; 144 struct user_struct *user; 145 union { 146 struct work_struct work; 147 struct rcu_head rcu; 148 }; 149 }; 150 151 struct bpf_array { 152 struct bpf_map map; 153 u32 elem_size; 154 /* 'ownership' of prog_array is claimed by the first program that 155 * is going to use this map or by the first program which FD is stored 156 * in the map to make sure that all callers and callees have the same 157 * prog_type and JITed flag 158 */ 159 enum bpf_prog_type owner_prog_type; 160 bool owner_jited; 161 union { 162 char value[0] __aligned(8); 163 void *ptrs[0] __aligned(8); 164 void __percpu *pptrs[0] __aligned(8); 165 }; 166 }; 167 #define MAX_TAIL_CALL_CNT 32 168 169 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 170 u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 171 void bpf_fd_array_map_clear(struct bpf_map *map); 172 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 173 174 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 175 const struct bpf_func_proto *bpf_get_event_output_proto(void); 176 177 #ifdef CONFIG_BPF_SYSCALL 178 DECLARE_PER_CPU(int, bpf_prog_active); 179 180 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 181 void bpf_register_map_type(struct bpf_map_type_list *tl); 182 183 struct bpf_prog *bpf_prog_get(u32 ufd); 184 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog); 185 void bpf_prog_put(struct bpf_prog *prog); 186 void bpf_prog_put_rcu(struct bpf_prog *prog); 187 188 struct bpf_map *bpf_map_get_with_uref(u32 ufd); 189 struct bpf_map *__bpf_map_get(struct fd f); 190 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref); 191 void bpf_map_put_with_uref(struct bpf_map *map); 192 void bpf_map_put(struct bpf_map *map); 193 int bpf_map_precharge_memlock(u32 pages); 194 195 extern int sysctl_unprivileged_bpf_disabled; 196 197 int bpf_map_new_fd(struct bpf_map *map); 198 int bpf_prog_new_fd(struct bpf_prog *prog); 199 200 int bpf_obj_pin_user(u32 ufd, const char __user *pathname); 201 int bpf_obj_get_user(const char __user *pathname); 202 203 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); 204 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); 205 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, 206 u64 flags); 207 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, 208 u64 flags); 209 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value); 210 211 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and 212 * forced to use 'long' read/writes to try to atomically copy long counters. 213 * Best-effort only. No barriers here, since it _will_ race with concurrent 214 * updates from BPF programs. Called from bpf syscall and mostly used with 215 * size 8 or 16 bytes, so ask compiler to inline it. 216 */ 217 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size) 218 { 219 const long *lsrc = src; 220 long *ldst = dst; 221 222 size /= sizeof(long); 223 while (size--) 224 *ldst++ = *lsrc++; 225 } 226 227 /* verify correctness of eBPF program */ 228 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 229 #else 230 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 231 { 232 } 233 234 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 235 { 236 return ERR_PTR(-EOPNOTSUPP); 237 } 238 239 static inline void bpf_prog_put(struct bpf_prog *prog) 240 { 241 } 242 #endif /* CONFIG_BPF_SYSCALL */ 243 244 /* verifier prototypes for helper functions called from eBPF programs */ 245 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 246 extern const struct bpf_func_proto bpf_map_update_elem_proto; 247 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 248 249 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 250 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 251 extern const struct bpf_func_proto bpf_tail_call_proto; 252 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 253 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 254 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 255 extern const struct bpf_func_proto bpf_get_current_comm_proto; 256 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 257 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 258 extern const struct bpf_func_proto bpf_get_stackid_proto; 259 260 /* Shared helpers among cBPF and eBPF. */ 261 void bpf_user_rnd_init_once(void); 262 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 263 264 #endif /* _LINUX_BPF_H */ 265