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