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 const struct bpf_map_ops *ops; 40 struct work_struct work; 41 }; 42 43 struct bpf_map_type_list { 44 struct list_head list_node; 45 const struct bpf_map_ops *ops; 46 enum bpf_map_type type; 47 }; 48 49 /* function argument constraints */ 50 enum bpf_arg_type { 51 ARG_DONTCARE = 0, /* unused argument in helper function */ 52 53 /* the following constraints used to prototype 54 * bpf_map_lookup/update/delete_elem() functions 55 */ 56 ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ 57 ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ 58 ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ 59 60 /* the following constraints used to prototype bpf_memcmp() and other 61 * functions that access data on eBPF program stack 62 */ 63 ARG_PTR_TO_STACK, /* any pointer to eBPF program stack */ 64 ARG_CONST_STACK_SIZE, /* number of bytes accessed from stack */ 65 66 ARG_PTR_TO_CTX, /* pointer to context */ 67 ARG_ANYTHING, /* any (initialized) argument is ok */ 68 }; 69 70 /* type of values returned from helper functions */ 71 enum bpf_return_type { 72 RET_INTEGER, /* function returns integer */ 73 RET_VOID, /* function doesn't return anything */ 74 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 75 }; 76 77 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 78 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 79 * instructions after verifying 80 */ 81 struct bpf_func_proto { 82 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 83 bool gpl_only; 84 enum bpf_return_type ret_type; 85 enum bpf_arg_type arg1_type; 86 enum bpf_arg_type arg2_type; 87 enum bpf_arg_type arg3_type; 88 enum bpf_arg_type arg4_type; 89 enum bpf_arg_type arg5_type; 90 }; 91 92 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 93 * the first argument to eBPF programs. 94 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 95 */ 96 struct bpf_context; 97 98 enum bpf_access_type { 99 BPF_READ = 1, 100 BPF_WRITE = 2 101 }; 102 103 struct bpf_verifier_ops { 104 /* return eBPF function prototype for verification */ 105 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 106 107 /* return true if 'size' wide access at offset 'off' within bpf_context 108 * with 'type' (read or write) is allowed 109 */ 110 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 111 112 u32 (*convert_ctx_access)(enum bpf_access_type type, int dst_reg, 113 int src_reg, int ctx_off, 114 struct bpf_insn *insn); 115 }; 116 117 struct bpf_prog_type_list { 118 struct list_head list_node; 119 const struct bpf_verifier_ops *ops; 120 enum bpf_prog_type type; 121 }; 122 123 struct bpf_prog; 124 125 struct bpf_prog_aux { 126 atomic_t refcnt; 127 u32 used_map_cnt; 128 const struct bpf_verifier_ops *ops; 129 struct bpf_map **used_maps; 130 struct bpf_prog *prog; 131 union { 132 struct work_struct work; 133 struct rcu_head rcu; 134 }; 135 }; 136 137 struct bpf_array { 138 struct bpf_map map; 139 u32 elem_size; 140 /* 'ownership' of prog_array is claimed by the first program that 141 * is going to use this map or by the first program which FD is stored 142 * in the map to make sure that all callers and callees have the same 143 * prog_type and JITed flag 144 */ 145 enum bpf_prog_type owner_prog_type; 146 bool owner_jited; 147 union { 148 char value[0] __aligned(8); 149 void *ptrs[0] __aligned(8); 150 }; 151 }; 152 #define MAX_TAIL_CALL_CNT 32 153 154 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); 155 void bpf_fd_array_map_clear(struct bpf_map *map); 156 bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); 157 const struct bpf_func_proto *bpf_get_trace_printk_proto(void); 158 159 #ifdef CONFIG_BPF_SYSCALL 160 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 161 void bpf_register_map_type(struct bpf_map_type_list *tl); 162 163 struct bpf_prog *bpf_prog_get(u32 ufd); 164 void bpf_prog_put(struct bpf_prog *prog); 165 void bpf_prog_put_rcu(struct bpf_prog *prog); 166 167 struct bpf_map *bpf_map_get(struct fd f); 168 void bpf_map_put(struct bpf_map *map); 169 170 /* verify correctness of eBPF program */ 171 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr); 172 #else 173 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl) 174 { 175 } 176 177 static inline struct bpf_prog *bpf_prog_get(u32 ufd) 178 { 179 return ERR_PTR(-EOPNOTSUPP); 180 } 181 182 static inline void bpf_prog_put(struct bpf_prog *prog) 183 { 184 } 185 #endif /* CONFIG_BPF_SYSCALL */ 186 187 /* verifier prototypes for helper functions called from eBPF programs */ 188 extern const struct bpf_func_proto bpf_map_lookup_elem_proto; 189 extern const struct bpf_func_proto bpf_map_update_elem_proto; 190 extern const struct bpf_func_proto bpf_map_delete_elem_proto; 191 192 extern const struct bpf_func_proto bpf_perf_event_read_proto; 193 extern const struct bpf_func_proto bpf_get_prandom_u32_proto; 194 extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; 195 extern const struct bpf_func_proto bpf_tail_call_proto; 196 extern const struct bpf_func_proto bpf_ktime_get_ns_proto; 197 extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto; 198 extern const struct bpf_func_proto bpf_get_current_uid_gid_proto; 199 extern const struct bpf_func_proto bpf_get_current_comm_proto; 200 extern const struct bpf_func_proto bpf_skb_vlan_push_proto; 201 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; 202 203 #endif /* _LINUX_BPF_H */ 204