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