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
26 struct 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
33 struct 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_HATYPE 28
127 #define SKF_AD_RXHASH 32
128 #define SKF_AD_CPU 36
129 #define SKF_AD_MAX 40
130 #define SKF_NET_OFF (-0x100000)
131 #define SKF_LL_OFF (-0x200000)
132
133 #ifdef __KERNEL__
134 struct sk_filter
135 {
136 atomic_t refcnt;
137 unsigned int len; /* Number of filter blocks */
138 struct rcu_head rcu;
139 struct sock_filter insns[0];
140 };
141
sk_filter_len(const struct sk_filter * fp)142 static inline unsigned int sk_filter_len(const struct sk_filter *fp)
143 {
144 return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
145 }
146
147 struct sk_buff;
148 struct sock;
149
150 extern int sk_filter(struct sock *sk, struct sk_buff *skb);
151 extern unsigned int sk_run_filter(const struct sk_buff *skb,
152 const struct sock_filter *filter);
153 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
154 extern int sk_detach_filter(struct sock *sk);
155 extern int sk_chk_filter(struct sock_filter *filter, int flen);
156 #endif /* __KERNEL__ */
157
158 #endif /* __LINUX_FILTER_H__ */
159