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#ifdef __KERNEL__
41struct sk_filter
42{
43 atomic_t refcnt;
44 unsigned int len; /* Number of filter blocks */
45 struct rcu_head rcu;
46 struct sock_filter insns[0];
47};
48
49static inline unsigned int sk_filter_len(struct sk_filter *fp)
50{
51 return fp->len*sizeof(struct sock_filter) + sizeof(*fp);
52}
53#endif
54
55/*
56 * Instruction classes
57 */
58
59#define BPF_CLASS(code) ((code) & 0x07)
60#define BPF_LD 0x00
61#define BPF_LDX 0x01
62#define BPF_ST 0x02
63#define BPF_STX 0x03
64#define BPF_ALU 0x04
65#define BPF_JMP 0x05
66#define BPF_RET 0x06
67#define BPF_MISC 0x07
68
69/* ld/ldx fields */
70#define BPF_SIZE(code) ((code) & 0x18)
71#define BPF_W 0x00
72#define BPF_H 0x08
73#define BPF_B 0x10
74#define BPF_MODE(code) ((code) & 0xe0)
75#define BPF_IMM 0x00
76#define BPF_ABS 0x20
77#define BPF_IND 0x40
78#define BPF_MEM 0x60
79#define BPF_LEN 0x80
80#define BPF_MSH 0xa0
81
82/* alu/jmp fields */
83#define BPF_OP(code) ((code) & 0xf0)
84#define BPF_ADD 0x00
85#define BPF_SUB 0x10
86#define BPF_MUL 0x20
87#define BPF_DIV 0x30
88#define BPF_OR 0x40
89#define BPF_AND 0x50
90#define BPF_LSH 0x60
91#define BPF_RSH 0x70
92#define BPF_NEG 0x80
93#define BPF_JA 0x00
94#define BPF_JEQ 0x10
95#define BPF_JGT 0x20
96#define BPF_JGE 0x30
97#define BPF_JSET 0x40
98#define BPF_SRC(code) ((code) & 0x08)
99#define BPF_K 0x00
100#define BPF_X 0x08
101
102/* ret - BPF_K and BPF_X also apply */
103#define BPF_RVAL(code) ((code) & 0x18)
104#define BPF_A 0x10
105
106/* misc */
107#define BPF_MISCOP(code) ((code) & 0xf8)
108#define BPF_TAX 0x00
109#define BPF_TXA 0x80
110
111#ifndef BPF_MAXINSNS
112#define BPF_MAXINSNS 4096
113#endif
114
115/*
116 * Macros for filter block array initializers.
117 */
118#ifndef BPF_STMT
119#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
120#endif
121#ifndef BPF_JUMP
122#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
123#endif
124
125/*
126 * Number of scratch memory words for: BPF_ST and BPF_STX
127 */
128#define BPF_MEMWORDS 16
129
130/* RATIONALE. Negative offsets are invalid in BPF.
131 We use them to reference ancillary data.
132 Unlike introduction new instructions, it does not break
133 existing compilers/optimizers.
134 */
135#define SKF_AD_OFF (-0x1000)
136#define SKF_AD_PROTOCOL 0
137#define SKF_AD_PKTTYPE 4
138#define SKF_AD_IFINDEX 8
139#define SKF_AD_MAX 12
140#define SKF_NET_OFF (-0x100000)
141#define SKF_LL_OFF (-0x200000)
142
143#ifdef __KERNEL__
144struct sk_buff;
145struct sock;
146
147extern unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen);
148extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
149extern int sk_detach_filter(struct sock *sk);
150extern int sk_chk_filter(struct sock_filter *filter, int flen);
151#endif /* __KERNEL__ */
152
153#endif /* __LINUX_FILTER_H__ */