summaryrefslogtreecommitdiff
path: root/include/linux/filter.h
blob: c6cb8f095088aada43f585eb51fc7c8fc4573cc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
/*
 * Linux Socket Filter Data Structures
 */

#ifndef __LINUX_FILTER_H__
#define __LINUX_FILTER_H__

#include <linux/compiler.h>
#include <linux/types.h>

#ifdef __KERNEL__
#include <asm/atomic.h>
#endif

/*
 * Current version of the filter code architecture.
 */
#define BPF_MAJOR_VERSION 1
#define BPF_MINOR_VERSION 1

/*
 *	Try and keep these values and structures similar to BSD, especially
 *	the BPF code definitions which need to match so you can share filters
 */
 
struct sock_filter	/* Filter block */
{
        __u16	code;   /* Actual filter code */
        __u8	jt;	/* Jump true */
        __u8	jf;	/* Jump false */
        __u32	k;      /* Generic multiuse field */
};

struct sock_fprog	/* Required for SO_ATTACH_FILTER. */
{
	unsigned short		len;	/* Number of filter blocks */
	struct sock_filter __user *filter;
};

#ifdef __KERNEL__
struct sk_filter
{
	atomic_t		refcnt;
        unsigned int         	len;	/* Number of filter blocks */
        struct sock_filter     	insns[0];
};

static inline unsigned int sk_filter_len(struct sk_filter *fp)
{
	return fp->len*sizeof(struct sock_filter) + sizeof(*fp);
}
#endif

/*
 * Instruction classes
 */

#define BPF_CLASS(code) ((code) & 0x07)
#define         BPF_LD          0x00
#define         BPF_LDX         0x01
#define         BPF_ST          0x02
#define         BPF_STX         0x03
#define         BPF_ALU         0x04
#define         BPF_JMP         0x05
#define         BPF_RET         0x06
#define         BPF_MISC        0x07

/* ld/ldx fields */
#define BPF_SIZE(code)  ((code) & 0x18)
#define         BPF_W           0x00
#define         BPF_H           0x08
#define         BPF_B           0x10
#define BPF_MODE(code)  ((code) & 0xe0)
#define         BPF_IMM         0x00
#define         BPF_ABS         0x20
#define         BPF_IND         0x40
#define         BPF_MEM         0x60
#define         BPF_LEN         0x80
#define         BPF_MSH         0xa0

/* alu/jmp fields */
#define BPF_OP(code)    ((code) & 0xf0)
#define         BPF_ADD         0x00
#define         BPF_SUB         0x10
#define         BPF_MUL         0x20
#define         BPF_DIV         0x30
#define         BPF_OR          0x40
#define         BPF_AND         0x50
#define         BPF_LSH         0x60
#define         BPF_RSH         0x70
#define         BPF_NEG         0x80
#define         BPF_JA          0x00
#define         BPF_JEQ         0x10
#define         BPF_JGT         0x20
#define         BPF_JGE         0x30
#define         BPF_JSET        0x40
#define BPF_SRC(code)   ((code) & 0x08)
#define         BPF_K           0x00
#define         BPF_X           0x08

/* ret - BPF_K and BPF_X also apply */
#define BPF_RVAL(code)  ((code) & 0x18)
#define         BPF_A           0x10

/* misc */
#define BPF_MISCOP(code) ((code) & 0xf8)
#define         BPF_TAX         0x00
#define         BPF_TXA         0x80

#ifndef BPF_MAXINSNS
#define BPF_MAXINSNS 4096
#endif

/*
 * Macros for filter block array initializers.
 */
#ifndef BPF_STMT
#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
#endif
#ifndef BPF_JUMP
#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
#endif

/*
 * Number of scratch memory words for: BPF_ST and BPF_STX
 */
#define BPF_MEMWORDS 16

/* RATIONALE. Negative offsets are invalid in BPF.
   We use them to reference ancillary data.
   Unlike introduction new instructions, it does not break
   existing compilers/optimizers.
 */
#define SKF_AD_OFF    (-0x1000)
#define SKF_AD_PROTOCOL 0
#define SKF_AD_PKTTYPE 	4
#define SKF_AD_IFINDEX 	8
#define SKF_AD_MAX 	12
#define SKF_NET_OFF   (-0x100000)
#define SKF_LL_OFF    (-0x200000)

#ifdef __KERNEL__
struct sk_buff;
struct sock;

extern unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen);
extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
extern int sk_chk_filter(struct sock_filter *filter, int flen);
#endif /* __KERNEL__ */

#endif /* __LINUX_FILTER_H__ */