Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
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 __u16 code; /* Actual filter code */
28 __u8 jt; /* Jump true */
29 __u8 jf; /* Jump false */
30 __u32 k; /* Generic multiuse field */
31};
32
33struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
34 unsigned short len; /* Number of filter blocks */
35 struct sock_filter __user *filter;
36};
37
38/*
39 * Instruction classes
40 */
41
42#define BPF_CLASS(code) ((code) & 0x07)
43#define BPF_LD 0x00
44#define BPF_LDX 0x01
45#define BPF_ST 0x02
46#define BPF_STX 0x03
47#define BPF_ALU 0x04
48#define BPF_JMP 0x05
49#define BPF_RET 0x06
50#define BPF_MISC 0x07
51
52/* ld/ldx fields */
53#define BPF_SIZE(code) ((code) & 0x18)
54#define BPF_W 0x00
55#define BPF_H 0x08
56#define BPF_B 0x10
57#define BPF_MODE(code) ((code) & 0xe0)
58#define BPF_IMM 0x00
59#define BPF_ABS 0x20
60#define BPF_IND 0x40
61#define BPF_MEM 0x60
62#define BPF_LEN 0x80
63#define BPF_MSH 0xa0
64
65/* alu/jmp fields */
66#define BPF_OP(code) ((code) & 0xf0)
67#define BPF_ADD 0x00
68#define BPF_SUB 0x10
69#define BPF_MUL 0x20
70#define BPF_DIV 0x30
71#define BPF_OR 0x40
72#define BPF_AND 0x50
73#define BPF_LSH 0x60
74#define BPF_RSH 0x70
75#define BPF_NEG 0x80
76#define BPF_JA 0x00
77#define BPF_JEQ 0x10
78#define BPF_JGT 0x20
79#define BPF_JGE 0x30
80#define BPF_JSET 0x40
81#define BPF_SRC(code) ((code) & 0x08)
82#define BPF_K 0x00
83#define BPF_X 0x08
84
85/* ret - BPF_K and BPF_X also apply */
86#define BPF_RVAL(code) ((code) & 0x18)
87#define BPF_A 0x10
88
89/* misc */
90#define BPF_MISCOP(code) ((code) & 0xf8)
91#define BPF_TAX 0x00
92#define BPF_TXA 0x80
93
94#ifndef BPF_MAXINSNS
95#define BPF_MAXINSNS 4096
96#endif
97
98/*
99 * Macros for filter block array initializers.
100 */
101#ifndef BPF_STMT
102#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
103#endif
104#ifndef BPF_JUMP
105#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
106#endif
107
108/*
109 * Number of scratch memory words for: BPF_ST and BPF_STX
110 */
111#define BPF_MEMWORDS 16
112
113/* RATIONALE. Negative offsets are invalid in BPF.
114 We use them to reference ancillary data.
115 Unlike introduction new instructions, it does not break
116 existing compilers/optimizers.
117 */
118#define SKF_AD_OFF (-0x1000)
119#define SKF_AD_PROTOCOL 0
120#define SKF_AD_PKTTYPE 4
121#define SKF_AD_IFINDEX 8
122#define SKF_AD_NLATTR 12
123#define SKF_AD_NLATTR_NEST 16
124#define SKF_AD_MARK 20
125#define SKF_AD_QUEUE 24
126#define SKF_AD_MAX 28
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__ */