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 ARG_CONST_STACK_SIZE_OR_ZERO, /* number of bytes accessed from stack or 0 */ 69 70 ARG_PTR_TO_CTX, /* pointer to context */ 71 ARG_ANYTHING, /* any (initialized) argument is ok */ 72 }; 73 74 /* type of values returned from helper functions */ 75 enum bpf_return_type { 76 RET_INTEGER, /* function returns integer */ 77 RET_VOID, /* function doesn't return anything */ 78 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 79 }; 80 81 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 82 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 83 * instructions after verifying 84 */ 85 struct bpf_func_proto { 86 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 87 bool gpl_only; 88 enum bpf_return_type ret_type; 89 enum bpf_arg_type arg1_type; 90 enum bpf_arg_type arg2_type; 91 enum bpf_arg_type arg3_type; 92 enum bpf_arg_type arg4_type; 93 enum bpf_arg_type arg5_type; 94 }; 95 96 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 97 * the first argument to eBPF programs. 98 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 99 */ 100 struct bpf_context; 101 102 enum bpf_access_type { 103 BPF_READ = 1, 104 BPF_WRITE = 2 105 }; 106 107 struct bpf_prog; 108 109 struct bpf_verifier_ops { 110 /* return eBPF function prototype for verification */ 111 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 112 113 /* return true if 'size' wide access at offset 'off' within bpf_context 114 * with 'type' (read or write) is allowed 115 */ 116 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 117 118 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 119 int src_reg, int ctx_off, 120 struct bpf_insn *insn, struct bpf_prog *prog); 121 }; 122 123 struct bpf_prog_type_list { 124 struct list_head list_node; 125 const struct bpf_verifier_ops *ops; 126 enum bpf_prog_type type; 127 }; 128 129 struct bpf_prog_aux { 130 atomic_t refcnt; 131 u32 used_map_cnt; 132 const struct bpf_verifier_ops *ops; 133 struct bpf_map **used_maps; 134 struct bpf_prog *prog; 135 struct user_struct *user; 136 union { 137 struct work_struct work; 138 struct rcu_head rcu; 139 }; 140 }; 141 142 struct bpf_array { 143 struct bpf_map map; 144 u32 elem_size; 145 /* 'ownership' of prog_array is claimed by the first program that 146 * is going to use this map or by the first program which FD is stored 147 * in the map to make sure that all callers and callees have the same 148 * prog_type and JITed flag 149 */ 150 enum bpf_prog_type owner_prog_type; 151 bool owner_jited; 152 union { 153 char value[0] __aligned(8); 154 void *ptrs[0] __aligned(8); 155 void __percpu *pptrs[0] __aligned(8); 156 }; 157 }; 158 #define MAX_TAIL_CALL_CNT 32 159 160 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 161 void bpf_fd_array_map_clear(struct bpf_map *map); 162 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 163 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 164 165 #ifdef CONFIG_BPF_SYSCALL 166 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 167 void bpf_register_map_type(struct bpf_map_type_list *tl); 168 169 struct bpf_prog *bpf_prog_get(u32 ufd); 170 void bpf_prog_put(struct bpf_prog *prog); 171 void bpf_prog_put_rcu(struct bpf_prog *prog); 172 173 struct bpf_map *bpf_map_get_with_uref(u32 ufd); 174 struct bpf_map *__bpf_map_get(struct fd f); 175 void bpf_map_inc(struct bpf_map *map, bool uref); 176 void bpf_map_put_with_uref(struct bpf_map *map); 177 void bpf_map_put(struct bpf_map *map); 178 179 extern int sysctl_unprivileged_bpf_disabled; 180 181 int bpf_map_new_fd(struct bpf_map *map); 182 int bpf_prog_new_fd(struct bpf_prog *prog); 183 184 int bpf_obj_pin_user(u32 ufd, const char __user *pathname); 185 int bpf_obj_get_user(const char __user *pathname); 186 187 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); 188 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); 189 int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, 190 u64 flags); 191 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, 192 u64 flags); 193 194 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and 195 * forced to use 'long' read/writes to try to atomically copy long counters. 196 * Best-effort only. No barriers here, since it _will_ race with concurrent 197 * updates from BPF programs. Called from bpf syscall and mostly used with 198 * size 8 or 16 bytes, so ask compiler to inline it. 199 */ 200 static inline void bpf_long_memcpy(void *dst, const void *src, u32 size) 201 { 202 const long *lsrc = src; 203 long *ldst = dst; 204 205 size /= sizeof(long); 206 while (size--) 207 *ldst++ = *lsrc++; 208 } 209 210 /* verify correctness of eBPF program */ 211 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 212 #else 213 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 214 { 215 } 216 217 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 218 { 219 return ERR_PTR(-EOPNOTSUPP); 220 } 221 222 static inline void bpf_prog_put(struct bpf_prog *prog) 223 { 224 } 225 #endif /* CONFIG_BPF_SYSCALL */ 226 227 /* verifier prototypes for helper functions called from eBPF programs */ 228 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 229 extern const struct bpf_func_proto bpf_map_update_elem_proto; 230 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 231 232 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 233 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 234 extern const struct bpf_func_proto bpf_tail_call_proto; 235 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 236 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 237 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 238 extern const struct bpf_func_proto bpf_get_current_comm_proto; 239 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 240 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 241 extern const struct bpf_func_proto bpf_get_stackid_proto; 242 243 /* Shared helpers among cBPF and eBPF. */ 244 void bpf_user_rnd_init_once(void); 245 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 246 247 #endif /* _LINUX_BPF_H */ 248