com.h3c.util.pkt

Class PacketReader

java.lang.Object

com.h3c.util.pkt.PacketReader

Direct Known Subclasses:

OfPacketReader

public class PacketReader
extends Object

Wraps a ByteBuffer and provides methods to read rich data types from it. Supported data types are from the com.h3c.util.ip package.

Constructor Summary

Constructors

Constructor and Description
PacketReader(ByteBuffer b) Constructs a packet reader wrapping a ByteBuffer.

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	array() Returns the byte array that backs this reader.
int	limit() Returns the limit of usable bytes.
int	odometer() Number of bytes read since creation of this reader or since the last call to reset the odometer.
byte	peek(int offset) Peek at the byte at the specified offset from current reader index.
int	peekU16() Peek at the next two bytes from the current position, interpreting them as an unsigned 16-bit value.
int	peekU16(int offset) Peek at the next two bytes from the given offset from the current position, interpreting them as an unsigned 16-bit value.
int	peekU24() Peek at the next three bytes from the current position, interpreting them as an unsigned 24-bit value.
int	peekU24(int offset) Peek at the next three bytes from the given offset from the current position, interpreting them as an unsigned 24-bit value.
short	peekU8() Peek at the next byte from the current position, interpreting it as an unsigned 8-bit value.
short	peekU8(int offset) Peek at the byte at the given offset from the current position, interpreting it as an unsigned 8-bit value.
int	readableBytes() Returns the count of readable bytes remaining.
BigPortNumber	readBigPortNumber() Reads a (u32) port number from the buffer.
byte	readByte() Reads and returns a single byte from the buffer.
byte[]	readBytes(int n) Reads the specified number of bytes from the buffer, returning them in a newly allocated array.
EthernetType	readEthernetType() Reads an Ethernet type from the buffer.
ICMPv4Type	readIcmpv4Type() Reads an ICMPv4 Type from the buffer.
ICMPv6Type	readIcmpv6Type() Reads an ICMPv6 Type from the buffer.
int	readInt() Reads four bytes as an int.
IpProtocol	readIpProtocol() Reads an IP Protocol from the buffer.
IpAddress	readIPv4Address() Reads an IPv4 address from the buffer.
IpAddress	readIPv6Address() Reads an IPv6 address from the buffer.
long	readLong() Reads eight bytes as a long.
MacAddress	readMacAddress() Reads a MAC address from the buffer.
PortNumber	readPortNumber() Reads a (u16) port number from the buffer.
String	readString(int n) Reads a string from the buffer.
int	readU16() Reads two bytes, interpreting them as an unsigned 16-bit value.
int	readU24() Reads three bytes, interpreting them as an unsigned 24-bit value.
long	readU32() Reads four bytes, interpreting them as an unsigned 32-bit value.
short	readU8() Reads a byte, interpreting it as an unsigned 8-bit value.
void	resetIndex() Resets the buffer position to the reader's original starting position.
void	resetOdometer() Resets the odometer to the current buffer position.
int	ri() Returns the reader index.
void	ri(int newPosition) Sets the reader index to the given position.
void	skip(int count) Skips buffer data by increasing the current reader index by the specified number of bytes.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

PacketReader

public PacketReader(ByteBuffer b)

Constructs a packet reader wrapping a ByteBuffer.

Parameters:

b - the byte buffer

Method Detail

toString

public String toString()

Overrides:

toString in class Object

odometer

public int odometer()

Number of bytes read since creation of this reader or since the last call to reset the odometer.

Returns:

the number of bytes read since creation or reset

resetOdometer

public void resetOdometer()

Resets the odometer to the current buffer position.

resetIndex

public void resetIndex()

Resets the buffer position to the reader's original starting position. The odometer is reset to 0.

ri

public int ri()

Returns the reader index.

Returns:

the reader index

ri

public void ri(int newPosition)

Sets the reader index to the given position. The new position must be non-negative and no larger than the current limit.

Parameters:

newPosition - the new position

Throws:

IllegalArgumentException - if preconditions for newPosition are not met

readableBytes

public int readableBytes()

Returns the count of readable bytes remaining.

Returns:

the number of readable bytes

limit

public int limit()

Returns the limit of usable bytes.

Returns:

the limit

array

public byte[] array()

Returns the byte array that backs this reader.

Returns:

the backing byte array

readIPv4Address

public IpAddress readIPv4Address()

Reads an IPv4 address from the buffer.

Returns:

an IP address (IPv4)

readIPv6Address

public IpAddress readIPv6Address()

Reads an IPv6 address from the buffer.

Returns:

an IP address (IPv6)

readMacAddress

public MacAddress readMacAddress()

Reads a MAC address from the buffer.

Returns:

a MAC address

readEthernetType

public EthernetType readEthernetType()

Reads an Ethernet type from the buffer.

Returns:

an Ethernet type

readIpProtocol

public IpProtocol readIpProtocol()

Reads an IP Protocol from the buffer.

Returns:

an IP Protocol

readIcmpv4Type

public ICMPv4Type readIcmpv4Type()

Reads an ICMPv4 Type from the buffer.

Returns:

an ICMPv4 type

readIcmpv6Type

public ICMPv6Type readIcmpv6Type()

Reads an ICMPv6 Type from the buffer.

Returns:

an ICMPv6 type

readPortNumber

public PortNumber readPortNumber()

Reads a (u16) port number from the buffer.

Returns:

a port number

readBigPortNumber

public BigPortNumber readBigPortNumber()

Reads a (u32) port number from the buffer.

Returns:

a big port number

readString

public String readString(int n)

Reads a string from the buffer. The data in the buffer is assumed to be in a field of length N, null terminated and encoded as ASCII. At the end of this operation the reader index of the underlying buffer will have advanced by N bytes.

Parameters:

n - the size of the string field

Returns:

a string

readBytes

public byte[] readBytes(int n)

Reads the specified number of bytes from the buffer, returning them in a newly allocated array.

Parameters:

n - the number of bytes to read

Returns:

a byte array containing the read bytes

readByte

public byte readByte()

Reads and returns a single byte from the buffer.

Returns:

the next byte in the buffer

skip

public void skip(int count)

Skips buffer data by increasing the current reader index by the specified number of bytes.

Parameters:

count - the number of bytes to skip

readInt

public int readInt()

Reads four bytes as an int.

Returns:

the int value

readLong

public long readLong()

Reads eight bytes as a long.

Returns:

the long value

readU8

public short readU8()

Reads a byte, interpreting it as an unsigned 8-bit value.

Returns:

the U8 equivalent of the byte read

peek

public byte peek(int offset)

Peek at the byte at the specified offset from current reader index.

Parameters:

offset - from the current reader index

Returns:

the byte at offset

peekU8

public short peekU8(int offset)

Peek at the byte at the given offset from the current position, interpreting it as an unsigned 8-bit value.

Parameters:

offset - the offset from the current position

Returns:

the U8 equivalent of the byte

peekU8

public short peekU8()

Peek at the next byte from the current position, interpreting it as an unsigned 8-bit value.

Returns:

the U8 equivalent of the byte

peekU16

public int peekU16(int offset)

Peek at the next two bytes from the given offset from the current position, interpreting them as an unsigned 16-bit value.

Parameters:

offset - the offset from the current position

Returns:

the U16 equivalent of the bytes read

peekU16

public int peekU16()

Peek at the next two bytes from the current position, interpreting them as an unsigned 16-bit value.

Returns:

the U16 equivalent of the bytes read

peekU24

public int peekU24(int offset)

Peek at the next three bytes from the given offset from the current position, interpreting them as an unsigned 24-bit value.

Parameters:

offset - the offset from the current position

Returns:

the U24 equivalent of the bytes read

peekU24

public int peekU24()

Peek at the next three bytes from the current position, interpreting them as an unsigned 24-bit value.

Returns:

the U24 equivalent of the bytes read

readU16

public int readU16()

Reads two bytes, interpreting them as an unsigned 16-bit value.

Returns:

the U16 equivalent of the bytes read

readU24

public int readU24()

Reads three bytes, interpreting them as an unsigned 24-bit value.

Returns:

the U24 equivalent of the bytes read

readU32

public long readU32()

Reads four bytes, interpreting them as an unsigned 32-bit value.

Returns:

the U32 equivalent of the bytes read