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