PcapWriter (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- net.i2p.client.streaming.impl.PcapWriter

All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
```
public class PcapWriter
extends Object
implements Closeable, Flushable
```
Write a standard pcap file with a "TCP" packet that can be analyzed with standard tools such as wireshark. The source and dest "IP" and "port" are fake but are generated from the hashes of the Destinations and stream ID's, so they will be consistent. The local "IP" will always be of the form 127.0.x.y Initial IP for a conn will be 127.0.0.0 for the local and 0.0.0.0 for the remote. Reference: http://wiki.wireshark.org/Development/LibpcapFileFormat The Jpcap library http://netresearch.ics.uci.edu/kfujii/jpcap/doc/ was close to what I want, but it requires you to instantiate a "captor" before you can write a file, and it requires a native lib to do so, and even then, it only wants to read the file, not write it. We even calculate a correct TCP header checksum to keep the tools happy. We don't, however, convert I2P-style sequence numbers, which count packets, to TCP-style byte counts. We don't track a lowest-acked-thru byte count atm, really. We do represent the window size in bytes though, so that's real confusing. This is designed to debug the streaming lib, but there are not log calls for every single packet - pings and pongs, and various odd cases where received packets are dropped, are not logged. Yes we could dump it natively and write a wireshark dissector. That sounds hard. And we wouldn't get the TCP stream analysis built into the tools.

Constructor Summary
Constructors
Constructor and Description
PcapWriter(I2PAppContext ctx, String file)
Creates a new PcapWriter that writes to the specified file in the log directory.

Constructors
Constructor and Description
`PcapWriter(I2PAppContext ctx, String file)` Creates a new PcapWriter that writes to the specified file in the log directory.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Closes the output stream, flushing any buffered data.
`void`	`flush()` Flushes any buffered data to the underlying output stream.
`void`	`write(Packet pkt, Connection con)` Write an inbound packet to the pcap file.
`void`	`write(PacketLocal pkt)` Write an outbound packet to the pcap file.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PcapWriter
```
public PcapWriter(I2PAppContext ctx,
                  String file)
           throws IOException
```
    Creates a new PcapWriter that writes to the specified file in the log directory.
    Parameters:
    ctx - the application context
    file - the filename to write (relative to the log directory)
    Throws:
    IOException - if the file cannot be opened or the header cannot be written
- Method Detail
  - close
```
public void close()
```
    Closes the output stream, flushing any buffered data. Errors during close are silently ignored.
    Specified by:
    close in interface Closeable
    Specified by:
    close in interface AutoCloseable
  - flush
```
public void flush()
```
    Flushes any buffered data to the underlying output stream. Errors during flush are silently ignored.
    Specified by:
    flush in interface Flushable
  - write
```
public void write(Packet pkt,
                  Connection con)
           throws IOException
```
    Write an inbound packet to the pcap file.
    Parameters:
    pkt - the inbound packet to write
    con - the connection, may be null
    Throws:
    IOException - if the packet cannot be written
  - write
```
public void write(PacketLocal pkt)
           throws IOException
```
    Write an outbound packet to the pcap file.
    Parameters:
    pkt - the outbound packet to write
    Throws:
    IOException - if the packet cannot be written

Class PcapWriter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

PcapWriter

Method Detail

close

flush

write

write