/*
   * 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

  enum {
  	BPF_S_RET_K = 0,
  	BPF_S_RET_A,
  	BPF_S_ALU_ADD_K,
  	BPF_S_ALU_ADD_X,
  	BPF_S_ALU_SUB_K,
  	BPF_S_ALU_SUB_X,
  	BPF_S_ALU_MUL_K,
  	BPF_S_ALU_MUL_X,
  	BPF_S_ALU_DIV_X,
  	BPF_S_ALU_AND_K,
  	BPF_S_ALU_AND_X,
  	BPF_S_ALU_OR_K,
  	BPF_S_ALU_OR_X,
  	BPF_S_ALU_LSH_K,
  	BPF_S_ALU_LSH_X,
  	BPF_S_ALU_RSH_K,
  	BPF_S_ALU_RSH_X,
  	BPF_S_ALU_NEG,
  	BPF_S_LD_W_ABS,
  	BPF_S_LD_H_ABS,
  	BPF_S_LD_B_ABS,
  	BPF_S_LD_W_LEN,
  	BPF_S_LD_W_IND,
  	BPF_S_LD_H_IND,
  	BPF_S_LD_B_IND,
  	BPF_S_LD_IMM,
  	BPF_S_LDX_W_LEN,
  	BPF_S_LDX_B_MSH,
  	BPF_S_LDX_IMM,
  	BPF_S_MISC_TAX,
  	BPF_S_MISC_TXA,
  	BPF_S_ALU_DIV_K,
  	BPF_S_LD_MEM,
  	BPF_S_LDX_MEM,
  	BPF_S_ST,
  	BPF_S_STX,
  	BPF_S_JMP_JA,
  	BPF_S_JMP_JEQ_K,
  	BPF_S_JMP_JEQ_X,
  	BPF_S_JMP_JGE_K,
  	BPF_S_JMP_JGE_X,
  	BPF_S_JMP_JGT_K,
  	BPF_S_JMP_JGT_X,
  	BPF_S_JMP_JSET_K,
  	BPF_S_JMP_JSET_X,
  };

  #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_NLATTR_NEST	16

  #define SKF_AD_MARK 	20

  #define SKF_AD_QUEUE	24

  #define SKF_AD_HATYPE	28
  #define SKF_AD_MAX	32

  #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__ */