/*

 * Linux Socket Filter Data Structures

 */

#ifndef __LINUX_FILTER_H__

#define __LINUX_FILTER_H__

#include <linux/compiler.h>

#include <linux/types.h>

#ifdef __KERNEL__

#include <asm/atomic.h>

#endif

/*

 * Current version of the filter code architecture.

 */

#define BPF_MAJOR_VERSION 1

#define BPF_MINOR_VERSION 1

/*

 *	Try and keep these values and structures similar to BSD, especially

 *	the BPF code definitions which need to match so you can share filters

 */

struct sock_filter	/* Filter block */

{

	__u16	code;   /* Actual filter code */

	__u8	jt;	/* Jump true */

	__u8	jf;	/* Jump false */

	__u32	k;      /* Generic multiuse field */

};

struct sock_fprog	/* Required for SO_ATTACH_FILTER. */

{

	unsigned short		len;	/* Number of filter blocks */

	struct sock_filter __user *filter;

};

/*

 * Instruction classes

 */

#define BPF_CLASS(code) ((code) & 0x07)

#define         BPF_LD          0x00

#define         BPF_LDX         0x01

#define         BPF_ST          0x02

#define         BPF_STX         0x03

#define         BPF_ALU         0x04

#define         BPF_JMP         0x05

#define         BPF_RET         0x06

#define         BPF_MISC        0x07

/* ld/ldx fields */

#define BPF_SIZE(code)  ((code) & 0x18)

#define         BPF_W           0x00

#define         BPF_H           0x08

#define         BPF_B           0x10

#define BPF_MODE(code)  ((code) & 0xe0)

#define         BPF_IMM         0x00

#define         BPF_ABS         0x20

#define         BPF_IND         0x40

#define         BPF_MEM         0x60

#define         BPF_LEN         0x80

#define         BPF_MSH         0xa0

/* alu/jmp fields */

#define BPF_OP(code)    ((code) & 0xf0)

#define         BPF_ADD         0x00

#define         BPF_SUB         0x10

#define         BPF_MUL         0x20

#define         BPF_DIV         0x30

#define         BPF_OR          0x40

#define         BPF_AND         0x50

#define         BPF_LSH         0x60

#define         BPF_RSH         0x70

#define         BPF_NEG         0x80

#define         BPF_JA          0x00

#define         BPF_JEQ         0x10

#define         BPF_JGT         0x20

#define         BPF_JGE         0x30

#define         BPF_JSET        0x40

#define BPF_SRC(code)   ((code) & 0x08)

#define         BPF_K           0x00

#define         BPF_X           0x08

/* ret - BPF_K and BPF_X also apply */

#define BPF_RVAL(code)  ((code) & 0x18)

#define         BPF_A           0x10

/* misc */

#define BPF_MISCOP(code) ((code) & 0xf8)

#define         BPF_TAX         0x00

#define         BPF_TXA         0x80

#ifndef BPF_MAXINSNS

#define BPF_MAXINSNS 4096

#endif

/*

 * Macros for filter block array initializers.

 */

#ifndef BPF_STMT

#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }

#endif

#ifndef BPF_JUMP

#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }

#endif

/*

 * Number of scratch memory words for: BPF_ST and BPF_STX

 */

#define BPF_MEMWORDS 16

/* RATIONALE. Negative offsets are invalid in BPF.

   We use them to reference ancillary data.

   Unlike introduction new instructions, it does not break

   existing compilers/optimizers.

 */

#define SKF_AD_OFF    (-0x1000)

#define SKF_AD_PROTOCOL 0

#define SKF_AD_PKTTYPE 	4

#define SKF_AD_IFINDEX 	8

#define SKF_AD_NLATTR	12

#define SKF_AD_MAX 	16

#define SKF_NET_OFF   (-0x100000)

#define SKF_LL_OFF    (-0x200000)

#ifdef __KERNEL__

struct sk_filter

{

	atomic_t		refcnt;

	unsigned int         	len;	/* Number of filter blocks */

	struct rcu_head		rcu;

	struct sock_filter     	insns[0];

};

static inline unsigned int sk_filter_len(const struct sk_filter *fp)

{

	return fp->len * sizeof(struct sock_filter) + sizeof(*fp);

}

struct sk_buff;

struct sock;

extern int sk_filter(struct sock *sk, struct sk_buff *skb);

extern unsigned int sk_run_filter(struct sk_buff *skb,

				  struct sock_filter *filter, int flen);

extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);

extern int sk_detach_filter(struct sock *sk);

extern int sk_chk_filter(struct sock_filter *filter, int flen);

#endif /* __KERNEL__ */

#endif /* __LINUX_FILTER_H__ */