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 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 struct bpf_map_ops *ops; 42 enum bpf_map_type type; 43 }; 44 45 void bpf_register_map_type(struct bpf_map_type_list *tl); 46 void bpf_map_put(struct bpf_map *map); 47 struct bpf_map *bpf_map_get(struct fd f); 48 49 /* function argument constraints */ 50 enum bpf_arg_type { 51 ARG_ANYTHING = 0, /* any argument is ok */ 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 67 /* type of values returned from helper functions */ 68 enum bpf_return_type { 69 RET_INTEGER, /* function returns integer */ 70 RET_VOID, /* function doesn't return anything */ 71 RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */ 72 }; 73 74 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs 75 * to in-kernel helper functions and for adjusting imm32 field in BPF_CALL 76 * instructions after verifying 77 */ 78 struct bpf_func_proto { 79 u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 80 bool gpl_only; 81 enum bpf_return_type ret_type; 82 enum bpf_arg_type arg1_type; 83 enum bpf_arg_type arg2_type; 84 enum bpf_arg_type arg3_type; 85 enum bpf_arg_type arg4_type; 86 enum bpf_arg_type arg5_type; 87 }; 88 89 /* bpf_context is intentionally undefined structure. Pointer to bpf_context is 90 * the first argument to eBPF programs. 91 * For socket filters: 'struct bpf_context *' == 'struct sk_buff *' 92 */ 93 struct bpf_context; 94 95 enum bpf_access_type { 96 BPF_READ = 1, 97 BPF_WRITE = 2 98 }; 99 100 struct bpf_verifier_ops { 101 /* return eBPF function prototype for verification */ 102 const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); 103 104 /* return true if 'size' wide access at offset 'off' within bpf_context 105 * with 'type' (read or write) is allowed 106 */ 107 bool (*is_valid_access)(int off, int size, enum bpf_access_type type); 108 }; 109 110 struct bpf_prog_type_list { 111 struct list_head list_node; 112 struct bpf_verifier_ops *ops; 113 enum bpf_prog_type type; 114 }; 115 116 void bpf_register_prog_type(struct bpf_prog_type_list *tl); 117 118 struct bpf_prog; 119 120 struct bpf_prog_aux { 121 atomic_t refcnt; 122 bool is_gpl_compatible; 123 enum bpf_prog_type prog_type; 124 struct bpf_verifier_ops *ops; 125 struct bpf_map **used_maps; 126 u32 used_map_cnt; 127 struct bpf_prog *prog; 128 struct work_struct work; 129 }; 130 131 #ifdef CONFIG_BPF_SYSCALL 132 void bpf_prog_put(struct bpf_prog *prog); 133 #else 134 static inline void bpf_prog_put(struct bpf_prog *prog) {} 135 #endif 136 struct bpf_prog *bpf_prog_get(u32 ufd); 137 /* verify correctness of eBPF program */ 138 int bpf_check(struct bpf_prog *fp, union bpf_attr *attr); 139 140 /* verifier prototypes for helper functions called from eBPF programs */ 141 extern struct bpf_func_proto bpf_map_lookup_elem_proto; 142 extern struct bpf_func_proto bpf_map_update_elem_proto; 143 extern struct bpf_func_proto bpf_map_delete_elem_proto; 144 145 #endif /* _LINUX_BPF_H */ 146