2 * Linux Socket Filter Data Structures
5 #ifndef __LINUX_FILTER_H__
6 #define __LINUX_FILTER_H__
8 #include <linux/compiler.h>
11 * Current version of the filter code architecture.
13 #define BPF_MAJOR_VERSION 1
14 #define BPF_MINOR_VERSION 1
17 * Try and keep these values and structures similar to BSD, especially
18 * the BPF code definitions which need to match so you can share filters
21 struct sock_filter /* Filter block */
23 __u16 code; /* Actual filter code */
24 __u8 jt; /* Jump true */
25 __u8 jf; /* Jump false */
26 __u32 k; /* Generic multiuse field */
29 struct sock_fprog /* Required for SO_ATTACH_FILTER. */
31 unsigned short len; /* Number of filter blocks */
32 struct sock_filter __user *filter;
39 unsigned int len; /* Number of filter blocks */
40 struct sock_filter insns[0];
43 static inline unsigned int sk_filter_len(struct sk_filter *fp)
45 return fp->len*sizeof(struct sock_filter) + sizeof(*fp);
53 #define BPF_CLASS(code) ((code) & 0x07)
64 #define BPF_SIZE(code) ((code) & 0x18)
68 #define BPF_MODE(code) ((code) & 0xe0)
77 #define BPF_OP(code) ((code) & 0xf0)
92 #define BPF_SRC(code) ((code) & 0x08)
96 /* ret - BPF_K and BPF_X also apply */
97 #define BPF_RVAL(code) ((code) & 0x18)
101 #define BPF_MISCOP(code) ((code) & 0xf8)
106 #define BPF_MAXINSNS 4096
110 * Macros for filter block array initializers.
113 #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
116 #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
120 * Number of scratch memory words for: BPF_ST and BPF_STX
122 #define BPF_MEMWORDS 16
124 /* RATIONALE. Negative offsets are invalid in BPF.
125 We use them to reference ancillary data.
126 Unlike introduction new instructions, it does not break
127 existing compilers/optimizers.
129 #define SKF_AD_OFF (-0x1000)
130 #define SKF_AD_PROTOCOL 0
131 #define SKF_AD_PKTTYPE 4
132 #define SKF_AD_IFINDEX 8
133 #define SKF_AD_MAX 12
134 #define SKF_NET_OFF (-0x100000)
135 #define SKF_LL_OFF (-0x200000)
138 extern int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen);
139 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
140 extern int sk_chk_filter(struct sock_filter *filter, int flen);
141 #endif /* __KERNEL__ */
143 #endif /* __LINUX_FILTER_H__ */