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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 _UAPI__LINUX_BPF_H__
8 #define _UAPI__LINUX_BPF_H__
9 
10 #include <linux/types.h>
11 #include <linux/bpf_common.h>
12 
13 /* Extended instruction set based on top of classic BPF */
14 
15 /* instruction classes */
16 #define BPF_ALU64	0x07	/* alu mode in double word width */
17 
18 /* ld/ldx fields */
19 #define BPF_DW		0x18	/* double word */
20 #define BPF_XADD	0xc0	/* exclusive add */
21 
22 /* alu/jmp fields */
23 #define BPF_MOV		0xb0	/* mov reg to reg */
24 #define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
25 
26 /* change endianness of a register */
27 #define BPF_END		0xd0	/* flags for endianness conversion: */
28 #define BPF_TO_LE	0x00	/* convert to little-endian */
29 #define BPF_TO_BE	0x08	/* convert to big-endian */
30 #define BPF_FROM_LE	BPF_TO_LE
31 #define BPF_FROM_BE	BPF_TO_BE
32 
33 #define BPF_JNE		0x50	/* jump != */
34 #define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
35 #define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
36 #define BPF_CALL	0x80	/* function call */
37 #define BPF_EXIT	0x90	/* function return */
38 
39 /* Register numbers */
40 enum {
41 	BPF_REG_0 = 0,
42 	BPF_REG_1,
43 	BPF_REG_2,
44 	BPF_REG_3,
45 	BPF_REG_4,
46 	BPF_REG_5,
47 	BPF_REG_6,
48 	BPF_REG_7,
49 	BPF_REG_8,
50 	BPF_REG_9,
51 	BPF_REG_10,
52 	__MAX_BPF_REG,
53 };
54 
55 /* BPF has 10 general purpose 64-bit registers and stack frame. */
56 #define MAX_BPF_REG	__MAX_BPF_REG
57 
58 struct bpf_insn {
59 	__u8	code;		/* opcode */
60 	__u8	dst_reg:4;	/* dest register */
61 	__u8	src_reg:4;	/* source register */
62 	__s16	off;		/* signed offset */
63 	__s32	imm;		/* signed immediate constant */
64 };
65 
66 /* BPF syscall commands */
67 enum bpf_cmd {
68 	/* create a map with given type and attributes
69 	 * fd = bpf(BPF_MAP_CREATE, union bpf_attr *, u32 size)
70 	 * returns fd or negative error
71 	 * map is deleted when fd is closed
72 	 */
73 	BPF_MAP_CREATE,
74 
75 	/* lookup key in a given map
76 	 * err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
77 	 * Using attr->map_fd, attr->key, attr->value
78 	 * returns zero and stores found elem into value
79 	 * or negative error
80 	 */
81 	BPF_MAP_LOOKUP_ELEM,
82 
83 	/* create or update key/value pair in a given map
84 	 * err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
85 	 * Using attr->map_fd, attr->key, attr->value
86 	 * returns zero or negative error
87 	 */
88 	BPF_MAP_UPDATE_ELEM,
89 
90 	/* find and delete elem by key in a given map
91 	 * err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
92 	 * Using attr->map_fd, attr->key
93 	 * returns zero or negative error
94 	 */
95 	BPF_MAP_DELETE_ELEM,
96 
97 	/* lookup key in a given map and return next key
98 	 * err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
99 	 * Using attr->map_fd, attr->key, attr->next_key
100 	 * returns zero and stores next key or negative error
101 	 */
102 	BPF_MAP_GET_NEXT_KEY,
103 
104 	/* verify and load eBPF program
105 	 * prog_fd = bpf(BPF_PROG_LOAD, union bpf_attr *attr, u32 size)
106 	 * Using attr->prog_type, attr->insns, attr->license
107 	 * returns fd or negative error
108 	 */
109 	BPF_PROG_LOAD,
110 };
111 
112 enum bpf_map_type {
113 	BPF_MAP_TYPE_UNSPEC,
114 };
115 
116 enum bpf_prog_type {
117 	BPF_PROG_TYPE_UNSPEC,
118 };
119 
120 union bpf_attr {
121 	struct { /* anonymous struct used by BPF_MAP_CREATE command */
122 		__u32	map_type;	/* one of enum bpf_map_type */
123 		__u32	key_size;	/* size of key in bytes */
124 		__u32	value_size;	/* size of value in bytes */
125 		__u32	max_entries;	/* max number of entries in a map */
126 	};
127 
128 	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
129 		__u32		map_fd;
130 		__aligned_u64	key;
131 		union {
132 			__aligned_u64 value;
133 			__aligned_u64 next_key;
134 		};
135 	};
136 
137 	struct { /* anonymous struct used by BPF_PROG_LOAD command */
138 		__u32		prog_type;	/* one of enum bpf_prog_type */
139 		__u32		insn_cnt;
140 		__aligned_u64	insns;
141 		__aligned_u64	license;
142 		__u32		log_level;	/* verbosity level of verifier */
143 		__u32		log_size;	/* size of user buffer */
144 		__aligned_u64	log_buf;	/* user supplied buffer */
145 	};
146 } __attribute__((aligned(8)));
147 
148 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
149  * function eBPF program intends to call
150  */
151 enum bpf_func_id {
152 	BPF_FUNC_unspec,
153 	__BPF_FUNC_MAX_ID,
154 };
155 
156 #endif /* _UAPI__LINUX_BPF_H__ */
157