NAME
Net::Connection::Sniffer -- gather stats on network connections
SYNOPSIS
use Net::Connection::Sniffer;
gather($config)DESCRIPTION
Net::Connection::Sniffer is a perl module to gather connection statistics by listening to ethernet traffic. Traffic is filtered using standard BPF notation as described in the tcpdump documentation and implemented using the standard pcap library to sniff packets on host network interfaces.
CONFIGURATION
Create a directory with appropriate permissions for the pid file and the profile statistics dump file. Typical installation:
mkdir -p /var/run/nc.snifferEdit the nc.sniffer.pl.sample file to change or set the following:
my $config = {
# specify the directory for the pid file for this daemon.
# The directory must exist and have writable permissions.
# [required]
#
piddir => '/var/run/nc.sniffer',
# specify the directory for the statistics file for this
# daemon. The directory must exist and have writable
# permissions
# [required]
#
sniffer => '/var/run/nc.sniffer',
# BPF filter statement. See examples below.
# [required]
#
bpf => 'src host myhost.com and tcp port 80',
# UDP listen port to trigger a dump file
# [optional]
#
port => 10004,
# HOST address on which to listen
# may be one of a HOSTNAME, IP address, or
# strings 'INADDR_ANY', 'INADDR_LOOPBACK'
# [optional] default 127.0.0.1 == INADDR_LOOPBACK
#
host => 'INADDR_LOOPBACK',
# ALLOWED connecting host(s)
# may be HOSTNAME or IP address
# [optional] default 127.0.0.1
#
allowed => ['127.0.0.1',],
};To generate a web report to STDOUT with or without a cache file, edit the nc.sniffer.cgi.sample file to change or set the configuration parameters. See Net::Connection::Sniffer::Report::web_report or the sample file for details.
Usage: <!--#exec cmd="./nc.sniffer.cgi 0" -->
or <!--#exec cmd="./nc.sniffer.cgi 1" -->where an argument of "0" produces a report ordered by /24 by usage and an argument of "1" produces a report ordered by subdomain by usage.
OPERATION
Launch the daemon with the command:
nc.sniffer.pl start
Syntax: nc.sniffer.pl start
nc.sniffer.pl stop
nc.sniffer.pl restart
nc.sniffer.pl status
nc.sniffer.pl dump
nc.sniffer.pl config
-d switch may be added to
redirect output to STDERROn most systems it will be necessary to wrap a shell script around nc.sniffer.pl if the path for perl is not in scope during boot.
#!/bin/sh
#
# shell script 'rc.nc.sniffer'
#
/path/to/nc.sniffer.pl $*A sample shell script is included in the distribution as rc.nc.sniffer
To run multiple copies of nc.sniffer for data collection on various ports or IP's at the same time, name them:
nc.sniffer1.pl
nc.sniffer2.pl
etc...
start start daemon if not running, write pid file
stop stop a running daemon
restart do stop, then start
status report if daemon running or not
dump refresh/write statistics file
config print configuration to STDOUTSIGNALS
The statistics information will be written to the file specified in the configuration upon receipt of a SIG USR1
SIG TERM write stats file, terminate
SIG HUP write stats file, start over
SIG USR1 write statistics fileUDP listener -- statistics file dump
If the nc.sniffer daemon is configured for a UDP listen port, sending a message dump will produce the same result as SIG USR1. The daemon will respond OK timestamp, but this is NOT syncronized with the file dump and only indicates that the statistics file should not have a timestamp earlier that the epoch value returned. When either a dump or SIG USR1 is issued, you must check the ctime of the file to determine if it has been updated.
BUGS / RESTRICTIONS
Net::Connection::Sniffer uses libpcap. The data collection is accomplished using a selectable capture device which is NOT SUPPORTED on Windows and some older BSD platforms. The next two paragraphs are from the pcap library and describe the platform limitations.
Some BPF ...devices do not support select() or poll() (for example, regular network devices on FreeBSD 4.3 and 4.4, and Endace DAG devices)...
...On most versions of most BSDs (including Mac OS X), select() and poll() do not work correctly on BPF devices. While a BPF file descriptor will be returned ...on most of those versions (the exceptions being FreeBSD 4.3 and 4.4), a simple select() or poll() will not return even after a... specified timeout expires... ...In FreeBSD 4.6 and later, select() and poll() work correctly on BPF devices...
BPF EXAMPLES
The bpf entry in the configuration hash uses the standard language documented in detail in the tcpdump man(1) page. The bpf statement must contain at a minimum, 'host somename [or IP address]'. The host specification must be for a single unique IP address and be the first such specification if there are multiple src/dest host specifications in the statment.
Capture all traffic to/from a particular host:
bpf => 'host particular.host.com',Capture traffic to/from your mail server:
bpf => 'host my.mx.com and tcp port 25',Capture request traffic arriving at your DNS server:
bpf => 'dst host my.dns.com and udp port 53',Capture response traffic leaving your DNS server:
bpf => 'src host my.dns.com and udp port 53',DUMP FILE FORMAT
The dump file is written in a format compatible with that produced by Data::Dumper. It may be imported for analysis using Perl's 'do' or by using File::SafeDO.
# start: 1145923212, Mon Apr 24 17:00:12 2006
# current: 1145923334, Mon Apr 24 17:02:14 2006
# hits: 3832 per minute
# bytes: 5927 per second
# users: 1234 users now
# device: eth1:1 non-promiscuous
# bpf: dst host my.host.com
{
my $dump = {
'69.3.95.131' => {
B => 240,
C => 4,
E => 1145760699,
N => ['hostname1','hostname2','...'],
R => 723,
S => 1145757331,
T => 1145790478,
W => 43359,
},
}start:
The start time of this data collection in seconds since the epoch and local time.
current:
The time the file was written in seconds since the epoch and local time.
hits:
The connections per minute collected by this filter configuration.
bytes:
The bandwidth in bytes per second collected by this filter configuration.
users:
The total number of discreet hosts logged at this instant
device:
The network device being sniffed and whether or not the device is in promiscuous mode.
bpf:
The bpf statment used for data collection
value hash pointer for one or more IP addresses.
Time values are seconds since the epoch.
Hash pointer = { IP address => { B => incremental byte count C => incremental connection count E => last update time N => ['hostname1','hostname2','...'], R => connections / hour S => start time this data set T => TTL expiration for hostname W => bytes / hour }, next IP address => { ...
EXPORTS
Only one function is exported by Sniffer.pm. This function is called in the nc.sniffer.pl.sample script to launch the nc.sniffer daemon.
PREREQUISITES
The pcap library (libpcap) which is part of tcpdump and is included in most *nix distributions. Available from:
http://sourceforge.net/projects/libpcap/NetAddr::IP::Util which is part of distribution NetAddr::IP::Lite
COPYRIGHT
Copyright 2004 - 2006, Michael Robinton <michael@bizsystems.com>
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License (except as noted otherwise in individuals sub modules) published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
AUTHOR
Michael Robinton <michael@bizsystems.com>
SEE ALSO
man (1) tcpdump
man (3) pcap