Linux::Proc::Net::TCP - Parser for Linux /proc/net/tcp and /proc/net/tcp6
use Linux::Proc::Net::TCP; my $table = Linux::Proc::Net::TCP->read; for my $entry (@$table) { printf("%s:%d --> %s:%d, %s\n", $entry->local_address, $entry->local_port, $entry->rem_address, $entry->rem_port, $entry->st ); }
This module can read and parse the information available from /proc/net/tcp in Linux systems.
reads /proc/net/tcp and /proc/net/tcp6 and returns an object representing a table of the connections.
/proc/net/tcp
/proc/net/tcp6
Individual entries in the table can be accessed just dereferencing the returned object. For instance:
for my $entry (@$table) { # do something with $entry }
The table entries are of class Linux::Proc::Net::TCP::Entry described below.
Linux::Proc::Net::TCP::Entry
This method accepts the following optional arguments:
disables parsing of the file /proc/net/tcp containing state information for TCP over IP4 connections
disables parsing of the file /proc/net/tcp6 containing state information for TCP over IP6 connections
overrides the default mount point for the procfs at /proc.
/proc
returns a list of the entries that are listeners:
for my $entry ($table->listeners) { printf "listener: %s:%d\n", $entry->local_address, $entry->local_port; }
returns the list of TCP ports where there are some service listening.
This method can be used to find some unused port:
my @used_ports = Linux::Proc::Net::TCP->read->listener_ports; my %used_port = map { $_ => 1 } @used_ports; my $port = $start; $port++ while $used_port{$port};
The entries in the table are of class Linux::Proc::Net::TCP::Entry and implement the following read only accessors:
sl local_address local_port rem_address rem_port st tx_queue rx_queue timer tm_when retrnsmt uid timeout inode reference_count memory_address retransmit_timeout predicted_tick ack_quick ack_pingpong sending_congestion_window slow_start_size_threshold ip4 ip6
This is the documentation about /proc/net/tcp available from the Linux kernel source distribution:
This document describes the interfaces /proc/net/tcp and /proc/net/tcp6. Note that these interfaces are deprecated in favor of tcp_diag. These /proc interfaces provide information about currently active TCP connections, and are implemented by tcp4_seq_show() in net/ipv4/tcp_ipv4.c and tcp6_seq_show() in net/ipv6/tcp_ipv6.c, respectively. It will first list all listening TCP sockets, and next list all established TCP connections. A typical entry of /proc/net/tcp would look like this (split up into 3 parts because of the length of the line): 46: 010310AC:9C4C 030310AC:1770 01 | | | | | |--> connection state | | | | |------> remote TCP port number | | | |-------------> remote IPv4 address | | |--------------------> local TCP port number | |---------------------------> local IPv4 address |----------------------------------> number of entry 00000150:00000000 01:00000019 00000000 | | | | |--> number of unrecovered RTO timeouts | | | |----------> number of jiffies until timer expires | | |----------------> timer_active (see below) | |----------------------> receive-queue |-------------------------------> transmit-queue 1000 0 54165785 4 cd1e6040 25 4 27 3 -1 | | | | | | | | | |--> slow start size threshold, | | | | | | | | | or -1 if the threshold | | | | | | | | | is >= 0xFFFF | | | | | | | | |----> sending congestion window | | | | | | | |-------> (ack.quick<<1)|ack.pingpong | | | | | | |---------> Predicted tick of soft clock | | | | | | (delayed ACK control data) | | | | | |------------> retransmit timeout | | | | |------------------> location of socket in memory | | | |-----------------------> socket reference count | | |-----------------------------> inode | |----------------------------------> unanswered 0-window probes |---------------------------------------------> uid timer_active: 0 no timer is pending 1 retransmit-timer is pending 2 another timer (e.g. delayed ack or keepalive) is pending 3 this is a socket in TIME_WAIT state. Not all fields will contain data (or even exist) 4 zero window probe timer is pending
Salvador Fandiño <sfandino@yahoo.com>
Copyright (C) 2010, 2012, 2014 by Qindel Formación y Servicios S.L.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.1 or, at your option, any later version of Perl 5 you may have available.
To install Linux::Proc::Net::TCP, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Linux::Proc::Net::TCP
CPAN shell
perl -MCPAN -e shell install Linux::Proc::Net::TCP
For more information on module installation, please visit the detailed CPAN module installation guide.