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 }; 44 45 struct bpf_map_type_list { 46 struct list_head list_node; 47 const struct bpf_map_ops *ops; 48 enum bpf_map_type type; 49 }; 50 51 /* function argument constraints */ 52 enum bpf_arg_type { 53 ARG_DONTCARE = 0, /* unused argument in helper function */ 54 55 /* the following constraints used to prototype 56 * bpf_map_lookup/update/delete_elem() functions 57 */ 58 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ 59 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ 60 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ 61 62 /* the following constraints used to prototype bpf_memcmp() and other 63 * functions that access data on eBPF program stack 64 */ 65 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */ 66 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */ 67 68 ARG_PTR_TO_CTX, /* pointer to context */ 69 ARG_ANYTHING, /* any (initialized) argument is ok */ 70 }; 71 72 /* type of values returned from helper functions */ 73 enum bpf_return_type { 74 RET_INTEGER, /* function returns integer */ 75 RET_VOID, /* function doesn't return anything */ 76 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 77 }; 78 79 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 80 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 81 * instructions after verifying 82 */ 83 struct bpf_func_proto { 84 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 85 bool gpl_only; 86 enum bpf_return_type ret_type; 87 enum bpf_arg_type arg1_type; 88 enum bpf_arg_type arg2_type; 89 enum bpf_arg_type arg3_type; 90 enum bpf_arg_type arg4_type; 91 enum bpf_arg_type arg5_type; 92 }; 93 94 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 95 * the first argument to eBPF programs. 96 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 97 */ 98 struct bpf_context; 99 100 enum bpf_access_type { 101 BPF_READ = 1, 102 BPF_WRITE = 2 103 }; 104 105 struct bpf_prog; 106 107 struct bpf_verifier_ops { 108 /* return eBPF function prototype for verification */ 109 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 110 111 /* return true if 'size' wide access at offset 'off' within bpf_context 112 * with 'type' (read or write) is allowed 113 */ 114 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 115 116 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 117 int src_reg, int ctx_off, 118 struct bpf_insn *insn, struct bpf_prog *prog); 119 }; 120 121 struct bpf_prog_type_list { 122 struct list_head list_node; 123 const struct bpf_verifier_ops *ops; 124 enum bpf_prog_type type; 125 }; 126 127 struct bpf_prog_aux { 128 atomic_t refcnt; 129 u32 used_map_cnt; 130 const struct bpf_verifier_ops *ops; 131 struct bpf_map **used_maps; 132 struct bpf_prog *prog; 133 struct user_struct *user; 134 union { 135 struct work_struct work; 136 struct rcu_head rcu; 137 }; 138 }; 139 140 struct bpf_array { 141 struct bpf_map map; 142 u32 elem_size; 143 /* 'ownership' of prog_array is claimed by the first program that 144 * is going to use this map or by the first program which FD is stored 145 * in the map to make sure that all callers and callees have the same 146 * prog_type and JITed flag 147 */ 148 enum bpf_prog_type owner_prog_type; 149 bool owner_jited; 150 union { 151 char value[0] __aligned(8); 152 void *ptrs[0] __aligned(8); 153 }; 154 }; 155 #define MAX_TAIL_CALL_CNT 32 156 157 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 158 void bpf_fd_array_map_clear(struct bpf_map *map); 159 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 160 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 161 162 #ifdef CONFIG_BPF_SYSCALL 163 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 164 void bpf_register_map_type(struct bpf_map_type_list *tl); 165 166 struct bpf_prog *bpf_prog_get(u32 ufd); 167 void bpf_prog_put(struct bpf_prog *prog); 168 void bpf_prog_put_rcu(struct bpf_prog *prog); 169 170 struct bpf_map *bpf_map_get(u32 ufd); 171 struct bpf_map *__bpf_map_get(struct fd f); 172 void bpf_map_put(struct bpf_map *map); 173 174 extern int sysctl_unprivileged_bpf_disabled; 175 176 int bpf_map_new_fd(struct bpf_map *map); 177 int bpf_prog_new_fd(struct bpf_prog *prog); 178 179 int bpf_obj_pin_user(u32 ufd, const char __user *pathname); 180 int bpf_obj_get_user(const char __user *pathname); 181 182 /* verify correctness of eBPF program */ 183 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 184 #else 185 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 186 { 187 } 188 189 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 190 { 191 return ERR_PTR(-EOPNOTSUPP); 192 } 193 194 static inline void bpf_prog_put(struct bpf_prog *prog) 195 { 196 } 197 #endif /* CONFIG_BPF_SYSCALL */ 198 199 /* verifier prototypes for helper functions called from eBPF programs */ 200 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 201 extern const struct bpf_func_proto bpf_map_update_elem_proto; 202 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 203 204 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 205 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 206 extern const struct bpf_func_proto bpf_tail_call_proto; 207 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 208 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 209 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 210 extern const struct bpf_func_proto bpf_get_current_comm_proto; 211 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 212 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 213 214 /* Shared helpers among cBPF and eBPF. */ 215 void bpf_user_rnd_init_once(void); 216 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 217 218 #endif /* _LINUX_BPF_H */ 219