Perl script as a sniffer with built-in statistics
C Clears the GUI
In other words, when the user presses c, the callback in line 46 sends a "clear"
event to interested parties, who used reg_cb()
to register with the TopGUI class object – in this case, the main program in Listing 1. This in turn calls the reset()
method in the TopCapture
module line 12, which causes it to reset the counter. The next timer call with stats()
finds empty entries; the call to the update()
method in line 40 of Listing 1 notifies the TopGUI
module, which in turn cleans up the GUI after the counters have been reset to zero.
When new packet data arrives, Listing 1 only needs to sort the stats data based on the counter state, format it with sprintf()
, and then call update()
in the TopGUI
module.
Anyone hoping that TShark will also grab packets not addressed to the current host on the current subnet should think again, however. Modern switches (in contrast to the hubs from 20 years ago) do not send all packets to all connected interfaces. Packets not addressed to the host on which tshark
is running, therefore, do not physically reach the host.
In a wireless LAN, however, all packets may reach all WiFi cards in the reception area, but these cards can rarely be switched to a mode in which packets addressed to other targets are forwarded to the analyzing host. If TShark is not installed on a router or a host with a special network card, it only shows the outgoing and incoming packets for the TShark host.
Infos
- Listings for this article: ftp://ftp.linux-magazine.com/pub/listings/magazine/180/
« Previous 1 2 3
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Linux Servers Targeted by Akira Ransomware
A group of bad actors who have already extorted $42 million have their sights set on the Linux platform.
-
TUXEDO Computers Unveils Linux Laptop Featuring AMD Ryzen CPU
This latest release is the first laptop to include the new CPU from Ryzen and Linux preinstalled.
-
XZ Gets the All-Clear
The back door xz vulnerability has been officially reverted for Fedora 40 and versions 38 and 39 were never affected.
-
Canonical Collaborates with Qualcomm on New Venture
This new joint effort is geared toward bringing Ubuntu and Ubuntu Core to Qualcomm-powered devices.
-
Kodi 21.0 Open-Source Entertainment Hub Released
After a year of development, the award-winning Kodi cross-platform, media center software is now available with many new additions and improvements.
-
Linux Usage Increases in Two Key Areas
If market share is your thing, you'll be happy to know that Linux is on the rise in two areas that, if they keep climbing, could have serious meaning for Linux's future.
-
Vulnerability Discovered in xz Libraries
An urgent alert for Fedora 40 has been posted and users should pay attention.
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs