Linux kernel mirror (for testing)
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linux
1/*
2 * Linux Socket Filter Data Structures
3 */
4
5#ifndef __LINUX_FILTER_H__
6#define __LINUX_FILTER_H__
7
8#include <linux/compiler.h>
9#include <linux/types.h>
10
11#ifdef __KERNEL__
12#include <asm/atomic.h>
13#endif
14
15/*
16 * Current version of the filter code architecture.
17 */
18#define BPF_MAJOR_VERSION 1
19#define BPF_MINOR_VERSION 1
20
21/*
22 * Try and keep these values and structures similar to BSD, especially
23 * the BPF code definitions which need to match so you can share filters
24 */
25
26struct sock_filter /* Filter block */
27{
28 __u16 code; /* Actual filter code */
29 __u8 jt; /* Jump true */
30 __u8 jf; /* Jump false */
31 __u32 k; /* Generic multiuse field */
32};
33
34struct sock_fprog /* Required for SO_ATTACH_FILTER. */
35{
36 unsigned short len; /* Number of filter blocks */
37 struct sock_filter __user *filter;
38};
39
40/*
41 * Instruction classes
42 */
43
44#define BPF_CLASS(code) ((code) & 0x07)
45#define BPF_LD 0x00
46#define BPF_LDX 0x01
47#define BPF_ST 0x02
48#define BPF_STX 0x03
49#define BPF_ALU 0x04
50#define BPF_JMP 0x05
51#define BPF_RET 0x06
52#define BPF_MISC 0x07
53
54/* ld/ldx fields */
55#define BPF_SIZE(code) ((code) & 0x18)
56#define BPF_W 0x00
57#define BPF_H 0x08
58#define BPF_B 0x10
59#define BPF_MODE(code) ((code) & 0xe0)
60#define BPF_IMM 0x00
61#define BPF_ABS 0x20
62#define BPF_IND 0x40
63#define BPF_MEM 0x60
64#define BPF_LEN 0x80
65#define BPF_MSH 0xa0
66
67/* alu/jmp fields */
68#define BPF_OP(code) ((code) & 0xf0)
69#define BPF_ADD 0x00
70#define BPF_SUB 0x10
71#define BPF_MUL 0x20
72#define BPF_DIV 0x30
73#define BPF_OR 0x40
74#define BPF_AND 0x50
75#define BPF_LSH 0x60
76#define BPF_RSH 0x70
77#define BPF_NEG 0x80
78#define BPF_JA 0x00
79#define BPF_JEQ 0x10
80#define BPF_JGT 0x20
81#define BPF_JGE 0x30
82#define BPF_JSET 0x40
83#define BPF_SRC(code) ((code) & 0x08)
84#define BPF_K 0x00
85#define BPF_X 0x08
86
87/* ret - BPF_K and BPF_X also apply */
88#define BPF_RVAL(code) ((code) & 0x18)
89#define BPF_A 0x10
90
91/* misc */
92#define BPF_MISCOP(code) ((code) & 0xf8)
93#define BPF_TAX 0x00
94#define BPF_TXA 0x80
95
96#ifndef BPF_MAXINSNS
97#define BPF_MAXINSNS 4096
98#endif
99
100/*
101 * Macros for filter block array initializers.
102 */
103#ifndef BPF_STMT
104#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
105#endif
106#ifndef BPF_JUMP
107#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
108#endif
109
110/*
111 * Number of scratch memory words for: BPF_ST and BPF_STX
112 */
113#define BPF_MEMWORDS 16
114
115/* RATIONALE. Negative offsets are invalid in BPF.
116 We use them to reference ancillary data.
117 Unlike introduction new instructions, it does not break
118 existing compilers/optimizers.
119 */
120#define SKF_AD_OFF (-0x1000)
121#define SKF_AD_PROTOCOL 0
122#define SKF_AD_PKTTYPE 4
123#define SKF_AD_IFINDEX 8
124#define SKF_AD_NLATTR 12
125#define SKF_AD_NLATTR_NEST 16
126#define SKF_AD_MAX 20
127#define SKF_NET_OFF (-0x100000)
128#define SKF_LL_OFF (-0x200000)
129
130#ifdef __KERNEL__
131struct sk_filter
132{
133 atomic_t refcnt;
134 unsigned int len; /* Number of filter blocks */
135 struct rcu_head rcu;
136 struct sock_filter insns[0];
137};
138
139static inline unsigned int sk_filter_len(const struct sk_filter *fp)
140{
141 return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
142}
143
144struct sk_buff;
145struct sock;
146
147extern int sk_filter(struct sock *sk, struct sk_buff *skb);
148extern unsigned int sk_run_filter(struct sk_buff *skb,
149 struct sock_filter *filter, int flen);
150extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
151extern int sk_detach_filter(struct sock *sk);
152extern int sk_chk_filter(struct sock_filter *filter, int flen);
153#endif /* __KERNEL__ */
154
155#endif /* __LINUX_FILTER_H__ */