org.jnetstream.filter.bpf
Class BPFInstruction

java.lang.Object
  org.jnetstream.filter.bpf.BPFInstruction

public class BPFInstruction
extends java.lang.Object

A single instruction of a BPF binary program. This is the equivelement to an assembly instruction. The representation here is more java friendly.

Author:

Mark Bednarczyk, Sly Technologies, Inc.

Nested Class Summary

static class

BPFInstruction.Symbol

Field Summary

int	code
int	jf
int	jt
long	k
BPFInstruction.Symbol	symbol

Constructor Summary

BPFInstruction(byte[] buf, int offset, java.nio.ByteOrder encoding)
Initializes the instruction from raw buffer data.

BPFInstruction(java.nio.ByteBuffer buf, int offset)
Initializes the instruction from raw buffer data.

BPFInstruction(int code, int jt, int jf, int k)

BPFInstruction(int code, int jt, int jf, long k)

Method Summary

byte[]	encodeToBinary()
static byte[]	encodeToBinary(BPFInstruction[] inst) Converts an array of BPF instructions to a binary program stored in a buffer.
int	getCode()
int	getJf()
int	getJt()
long	getK()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

code

public final int code

jf

public final int jf

jt

public final int jt

k

public final long k

symbol

public final BPFInstruction.Symbol symbol

Constructor Detail

BPFInstruction

public BPFInstruction(byte[] buf,
                      int offset,
                      java.nio.ByteOrder encoding)
               throws IllegalInstructionException

Initializes the instruction from raw buffer data. Each instruction is 64-bits wide and has the following structure:

 
 struct bpf_insn { u_short code; u_char jt; u_char jf; bpf_int32 k; };
 
 

Parameters:

buf - buffer to extract the structure from

offset - offset within the buffer to read the structure

Throws:

IllegalInstructionException

BPFInstruction

public BPFInstruction(java.nio.ByteBuffer buf,
                      int offset)

Initializes the instruction from raw buffer data. Each instruction is 64-bits wide and has the following structure:

 
 struct bpf_insn { u_short code; u_char jt; u_char jf; bpf_int32 k; };
 
 

Parameters:

buf - buffer to extract the structure from

offset - offset within the buffer to read the structure

BPFInstruction

public BPFInstruction(int code,
                      int jt,
                      int jf,
                      int k)
               throws IllegalInstructionException

Throws:

IllegalInstructionException

BPFInstruction

public BPFInstruction(int code,
                      int jt,
                      int jf,
                      long k)

Parameters:

code - BPF op code

jt - jump address

jf - jump address

k - base offset

Method Detail

encodeToBinary

public static byte[] encodeToBinary(BPFInstruction[] inst)

Converts an array of BPF instructions to a binary program stored in a buffer.

Parameters:

inst - instruction array to do the conversion of

Returns:

buffer containing the converted binary bpf program

encodeToBinary

public byte[] encodeToBinary()

Returns:

getCode

public final int getCode()

Returns:

Returns the code.

getJf

public final int getJf()

Returns:

Returns the jf.

getJt

public final int getJt()

Returns:

Returns the jt.

getK

public final long getK()

Returns:

Returns the k.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object