---
name: "Net::Frame::Dump::Online2"
section: "3pm"
platform: "linux"
package: "libnet-frame-dump-perl"
version: "1.18-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Net::Frame::Dump::Online2"
---

# Net::Frame::Dump::Online2(3pm)

tcpdump like implementation, online mode and non-blocking

## NAME

Net::Frame::Dump::Online2 - tcpdump like implementation, online mode and non-blocking

## SYNOPSIS

```
   use Net::Frame::Dump::Online2;
   #
   # Simply create a Dump object
   #
   my $oDump = Net::Frame::Dump::Online2->new(
      dev => 'eth0',
   );
   $oDump->start;
   # Gather frames
   while (1) {
      if (my $f = $oDump->next) {
         my $raw            = $f->{raw};
         my $firstLayerType = $f->{firstLayer};
         my $timestamp      = $f->{timestamp};
      }
   }
   $oDump->stop;
   #
   # Default parameters on creation
   #
   my $oDumpDefault = Net::Frame::Dump::Online2->new(
      timeoutOnNext => 3,
      timeout       => 0,
      promisc       => 0,
      snaplen       => 1514,
      file          => '',
      overwrite     => 0,
   );
```

## DESCRIPTION

This module implements a tcpdump-like program, for live capture from networks.

## ATTRIBUTES

- **dev**

  The network interface to listen on. No default value.

- **timeoutOnNext**

  Each time you call **next** method, an internal counter is updated. This counter tells you if you have not received any data since **timeoutOnNext** seconds. When a timeout occurred, **timeout** is set to true.

- **timeout**

  When **timeoutOnNext** seconds has been reached, this variable is set to true, and never reset. See **timeoutReset** if you want to reset it.

- **snaplen**

  If you want to capture a different snaplen, set it a number. Default to 1514.

- **promisc**

  By default, interface is not put into promiscuous mode, set this parameter to true if you want it.

The following are inherited attributes:

- **filter**

  Pcap filter to use. Default to no filter.

- **firstLayer**

  Stores information about the first layer type contained on read frame. This attribute is filled only after a call to **start** method.

- **isRunning**

  Returns true if a call to **start** has been done, false otherwise or if a call to **stop** has been done.

- **keepTimestamp**

  Sometimes, when frames are captured and saved to a .pcap file, timestamps sucks. That is, you send a frame, and receive the reply, but your request appear to have been sent after the reply. So, to correct that, you can use **Net::Frame::Dump** own timestamping system. The default is 0. Set it manually to 1 if you need original .pcap frames timestamps.

## METHODS

- **new**

  - **new** (hash)

  Object constructor. You can pass attributes that will overwrite default ones. See **SYNOPSIS** for default values.

- **start**

  When you want to start reading frames from network, call this method.

- **stop**

  When you want to stop reading frames from network, call this method.

- **next**

  Returns the next captured frame; undef if none awaiting. Each time this method is called, a comparison is done to see if no frame has been captured during **timeoutOnNext** number of seconds. If so, **timeout** attribute is set to 1 to reflect the pending timeout.

- **store** (**Net::Frame::Simple** object)

  This method will store internally, sorted, the **Net::Frame::Simple** object passed as a single parameter. **getKey** methods, implemented in various **Net::Frame::Layer** objects will be used to efficiently retrieve (via **getKeyReverse** method) frames.

  Basically, it is used to make **recv** method (from **Net::Frame::Simple**) to retrieve quickly the reply frame for a request frame.

- **getFramesFor** (**Net::Frame::Simple** object)

  This will return an array of possible reply frames for the specified **Net::Frame::Simple** object. For example, reply frames for a UDP probe will be all the frames which have the same source port and destination port as the request.

- **flush**

  Will flush stored frames, the one which have been stored via **store** method.

- **timeoutReset**

  Reset the internal timeout state (**timeout** attribute).

- **getStats**

  Tries to get packet statistics on an open descriptor. It returns a reference to a hash that has to following fields: **ps\_recv**, **ps\_drop**, **ps\_ifdrop**.

## SEE ALSO

Net::Frame::Dump

## AUTHOR

Patrice \<GomoR\> Auffret

## COPYRIGHT AND LICENSE

Copyright (c) 2006-2020, Patrice \<GomoR\> Auffret

You may distribute this module under the terms of the Artistic license. See LICENSE.Artistic file in the source distribution archive.