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 29 struct bpf_map { 30 atomic_t refcnt; 31 enum bpf_map_type map_type; 32 u32 key_size; 33 u32 value_size; 34 u32 max_entries; 35 const struct bpf_map_ops *ops; 36 struct work_struct work; 37 }; 38 39 struct bpf_map_type_list { 40 struct list_head list_node; 41 const struct bpf_map_ops *ops; 42 enum bpf_map_type type; 43 }; 44 45 /* function argument constraints */ 46 enum bpf_arg_type { 47 ARG_DONTCARE = 0, /* unused argument in helper function */ 48 49 /* the following constraints used to prototype 50 * bpf_map_lookup/update/delete_elem() functions 51 */ 52 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ 53 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ 54 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ 55 56 /* the following constraints used to prototype bpf_memcmp() and other 57 * functions that access data on eBPF program stack 58 */ 59 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */ 60 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */ 61 62 ARG_PTR_TO_CTX, /* pointer to context */ 63 ARG_ANYTHING, /* any (initialized) argument is ok */ 64 }; 65 66 /* type of values returned from helper functions */ 67 enum bpf_return_type { 68 RET_INTEGER, /* function returns integer */ 69 RET_VOID, /* function doesn't return anything */ 70 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 71 }; 72 73 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 74 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 75 * instructions after verifying 76 */ 77 struct bpf_func_proto { 78 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 79 bool gpl_only; 80 enum bpf_return_type ret_type; 81 enum bpf_arg_type arg1_type; 82 enum bpf_arg_type arg2_type; 83 enum bpf_arg_type arg3_type; 84 enum bpf_arg_type arg4_type; 85 enum bpf_arg_type arg5_type; 86 }; 87 88 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 89 * the first argument to eBPF programs. 90 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 91 */ 92 struct bpf_context; 93 94 enum bpf_access_type { 95 BPF_READ = 1, 96 BPF_WRITE = 2 97 }; 98 99 struct bpf_verifier_ops { 100 /* return eBPF function prototype for verification */ 101 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 102 103 /* return true if 'size' wide access at offset 'off' within bpf_context 104 * with 'type' (read or write) is allowed 105 */ 106 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 107 108 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 109 int src_reg, int ctx_off, 110 struct bpf_insn *insn); 111 }; 112 113 struct bpf_prog_type_list { 114 struct list_head list_node; 115 const struct bpf_verifier_ops *ops; 116 enum bpf_prog_type type; 117 }; 118 119 struct bpf_prog; 120 121 struct bpf_prog_aux { 122 atomic_t refcnt; 123 u32 used_map_cnt; 124 const struct bpf_verifier_ops *ops; 125 struct bpf_map **used_maps; 126 struct bpf_prog *prog; 127 union { 128 struct work_struct work; 129 struct rcu_head rcu; 130 }; 131 }; 132 133 struct bpf_array { 134 struct bpf_map map; 135 u32 elem_size; 136 /* 'ownership' of prog_array is claimed by the first program that 137 * is going to use this map or by the first program which FD is stored 138 * in the map to make sure that all callers and callees have the same 139 * prog_type and JITed flag 140 */ 141 enum bpf_prog_type owner_prog_type; 142 bool owner_jited; 143 union { 144 char value[0] __aligned(8); 145 struct bpf_prog *prog[0] __aligned(8); 146 }; 147 }; 148 #define MAX_TAIL_CALL_CNT 32 149 150 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 151 void bpf_prog_array_map_clear(struct bpf_map *map); 152 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 153 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 154 155 #ifdef CONFIG_BPF_SYSCALL 156 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 157 void bpf_register_map_type(struct bpf_map_type_list *tl); 158 159 struct bpf_prog *bpf_prog_get(u32 ufd); 160 void bpf_prog_put(struct bpf_prog *prog); 161 void bpf_prog_put_rcu(struct bpf_prog *prog); 162 163 struct bpf_map *bpf_map_get(struct fd f); 164 void bpf_map_put(struct bpf_map *map); 165 166 /* verify correctness of eBPF program */ 167 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 168 #else 169 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 170 { 171 } 172 173 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 174 { 175 return ERR_PTR(-EOPNOTSUPP); 176 } 177 178 static inline void bpf_prog_put(struct bpf_prog *prog) 179 { 180 } 181 #endif /* CONFIG_BPF_SYSCALL */ 182 183 /* verifier prototypes for helper functions called from eBPF programs */ 184 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 185 extern const struct bpf_func_proto bpf_map_update_elem_proto; 186 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 187 188 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 189 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 190 extern const struct bpf_func_proto bpf_tail_call_proto; 191 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 192 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 193 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 194 extern const struct bpf_func_proto bpf_get_current_comm_proto; 195 196 #endif /* _LINUX_BPF_H */ 197