io.pkts.packet.impl

Class PCapPacketImpl

java.lang.Object

io.pkts.packet.impl.AbstractPacket

io.pkts.packet.impl.PCapPacketImpl

All Implemented Interfaces:

Packet, PCapPacket, Cloneable

public final class PCapPacketImpl
extends AbstractPacket
implements PCapPacket

TODO: may rename this to a frame instead since this is a little different than a "real" protocol packet.

Author:

jonas@jonasborjesson.com

Constructor Summary

Constructors

Constructor and Description
PCapPacketImpl(PcapGlobalHeader pcapGlobalHeader, PcapRecordHeader header, Buffer payload) Constructor which uses the PCAP file's global header to support more than just Ethernet link layers
PCapPacketImpl(PcapRecordHeader header, Buffer payload) Constructor which assumes an Ethernet link layer.

Method Summary

Modifier and Type	Method and Description
PCapPacket	clone()
long	getArrivalTime() The arrival time of this packet in microseconds relative to epoch (midnight UTC of January 1, 1970).
long	getCapturedLength() Get the actual length of what is contained in this frame.
Packet	getNextPacket() Get the next frame, or null if there is none.
long	getTotalLength() Get the total length of the data.
String	toString()
void	verify() Calling this method will force the packet to completely parse its data and check so that all the information conforms to whatever rules this packet needs to follow.
void	write(OutputStream out, Buffer payload) Writes this packet to the OutputStream with the supplied payload.

Methods inherited from class io.pkts.packet.impl.AbstractPacket

checkParent, getName, getPacket, getParentPacket, getPayload, getProtocol, hasProtocol, write

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.pkts.packet.Packet

getName, getPacket, getParentPacket, getPayload, getProtocol, hasProtocol, write

Constructor Detail

PCapPacketImpl

public PCapPacketImpl(PcapRecordHeader header,
                      Buffer payload)

Constructor which assumes an Ethernet link layer.

PCapPacketImpl

public PCapPacketImpl(PcapGlobalHeader pcapGlobalHeader,
                      PcapRecordHeader header,
                      Buffer payload)

Constructor which uses the PCAP file's global header to support more than just Ethernet link layers

Method Detail

getArrivalTime

public long getArrivalTime()

The arrival time of this packet in microseconds relative to epoch (midnight UTC of January 1, 1970). Note, since this returns with microseconds precision (which may or may not be relevant depending on the hardware on which the packet was captured on) and you wish to format this arrival time into a more human readable format you could use the SimpleDateFormat but it can only handle milliseconds precision (you will have to write your own date formatter if you want microseconds). Here is a snippet illustrating how to turn the arrival time of the packet into a human readable date

 Packet p = ...;
 SimpleDateFormat formatter = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss.SSS");
 Date date = new Date(p.getArrivalTime() / 1000);
 System.out.println("Arrival time: " + formatter.format(date));
 

Note how an integer devision is performed on the arrival time to "cut off" the microseconds from the time stamp

Specified by:

getArrivalTime in interface Packet

Returns:

the arrival time of the packet in microseconds since the start of the epoch

getTotalLength

public long getTotalLength()

Description copied from interface: PCapPacket

Get the total length of the data. Not all of that data may have been captured in this one frame, which is evident if the actual captured length is different from the total length

Specified by:

getTotalLength in interface PCapPacket

Returns:

getCapturedLength

public long getCapturedLength()

Description copied from interface: PCapPacket

Get the actual length of what is contained in this frame. Note, if the captured length is different from the total length then we have a fragmented packet

Specified by:

getCapturedLength in interface PCapPacket

Returns:

the length in bytes

verify

public void verify()

Calling this method will force the packet to completely parse its data and check so that all the information conforms to whatever rules this packet needs to follow. E.g., if this happens to be a SIP packet, then it will check if it has the mandatory headers etc. Some simpler packets, such as the IPPacket, hardly does anything in this method but more complex protocols such as SIP (once again), HTTP etc can spend quite some time verifying everything, which is why you don't want to do it unless you really have to. In general, yajpcap has the philosophy of "assume that everything is ok until things blow up and then deal with it"

Specified by:

verify in interface Packet

Overrides:

verify in class AbstractPacket

toString

public String toString()

Overrides:

toString in class Object

write

public void write(OutputStream out,
                  Buffer payload)
           throws IOException

Description copied from interface: Packet

Writes this packet to the OutputStream with the supplied payload. You can use this method to e.g. write a raw UDPPacket to the stream with this payload. Note, if the UDPPacket already had a payload it will be ignored so use this method with care.

Specified by:

write in interface Packet

Throws:

IOException

clone

public PCapPacket clone()

Specified by:

clone in interface Packet

Specified by:

clone in interface PCapPacket

Specified by:

clone in class AbstractPacket

getNextPacket

public Packet getNextPacket()
                     throws IOException,
                            PacketParseException

Description copied from interface: Packet

Get the next frame, or null if there is none. Note, if there isn't another frame but there is still raw data within this frame, it only means that we didn't recognize the payload.

Specified by:

getNextPacket in interface Packet

Returns:

Throws:

IOException

PacketParseException - if the next packet can't be parsed by the framer