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#!/usr/bin/perl
# A Hobbit client-side module to check the local network interface
# states (e.g. "needs to be up", "needs to be in promiscuous mode",
# etc.).
#
# Copyright (C) 2018-2022 Axel Beckert <abe@debian.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as 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
use strict;
use warnings;
use 5.010;
use Hobbit;
use YAML::Tiny;
use Sys::Hostname;
use File::Which;
use File::Slurp qw(read_file);
my $interval = 10; # How long to measure packet amounts in seconds
my @config_file_locations = qw(
/etc/xymon/net.yaml
/etc/xymon-client/net.yaml
);
my %netstat_field = (
'RX-OK' => 2,
'RX-ERR' => 3,
'TX-OK' => 10,
'TX-ERR' => 11,
);
my $config_file;
foreach my $location (@config_file_locations) {
if (-e $location) {
$config_file = $location;
last;
}
}
exit 0 unless defined $config_file and -e $config_file;
my $bb = new Hobbit('net');
my $hostname = hostname;
my $config;
# Try to parse the YAML configuration and throw a warning if the
# YAML::Tiny parser fails. Needs to copy with different generations of
# YAML::Tiny which have different behaviour on errors.
my $config_yaml = YAML::Tiny->read($config_file);
unless (defined $config_yaml) {
$bb->color_line( 'red',
"YAML::Tiny couldn't parse $config_file.\n".
( defined($YAML::Tiny::errstr) ?
$YAML::Tiny::errstr."\n" :
'' ));
$bb->send;
exit 0;
};
# Look for my hostname in the configuration file and exit if it's not
# in there.
$config = $config_yaml->[0]{$hostname} if ( exists($config_yaml->[0]) and
exists($config_yaml->[0]{$hostname}) and
defined($config_yaml->[0]{$hostname}) );
exit 0 unless $config;
my %if_cache;
my %special_case = (
'Full' => 'Duplex: Full',
'Half' => 'Duplex: Half',
'TP' => 'Port: Twisted Pair',
'Twisted Pair' => 'Port: Twisted Pair',
'FIBRE' => 'Port: FIBRE',
);
# Check if at least one of the two binaries is present
my $ip_bin = which 'ip';
my $ifconfig_bin = which 'ifconfig';
my $ethtool_bin = which 'ethtool';
if ($ip_bin or $ifconfig_bin) {
my @interfaces = ();
if (ref($config) eq 'ARRAY') {
@interfaces = @$config;
foreach my $interface (@interfaces) {
![Axel Beckert Axel Beckert's avatar](/uploads/-/system/user/avatar/1582/avatar.png?width=72)
Axel Beckert
committed
check_if_state($interface, 'UP');
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}
} elsif (ref($config) eq 'HASH') {
@interfaces = sort keys %$config;
foreach my $interface (@interfaces) {
#if_exists($interface);
if (ref($config->{$interface}) eq 'ARRAY') {
my @states = @{$config->{$interface}};
foreach my $state (@states) {
my $color = 'yellow';
if (ref($state) eq 'HASH') {
# TODO: Support more than one key value pair per line
my $old_state = $state;
$state = (keys %$old_state)[0];
$color = (values %$old_state)[0];
#use Data::Dumper;
#die Dumper [$old_state, $state, $color];
}
check_if_state($interface, $state, $color);
}
} elsif (ref($config->{$interface}) eq 'HASH') {
my $if_state = $config->{$interface};
my @states = sort keys %$if_state;
foreach my $state (@states) {
check_if_state($interface, $state, $if_state->{$state});
}
} else {
$bb->color_line(
'yellow',
"$hostname -> $interface is not a YAML list or hash, skipping.\n"
);
}
}
}
} else {
# Neither ifconfig nor ip is found?!? Strange installation, that.
$bb->color_line(
'red',
"$config_file exists, but neither ip nor ifconfig can be found in $ENV{PATH}.\n"
);
}
$bb->send;
###
### Functions
###
sub parse_proc_net_dev {
my $contents = shift;
my $matrix = [];
foreach my $line (split(/\n/, $contents)) {
# Ignore headers
next unless $line =~ /:/;
push(@$matrix, [ split(' ', $line) ]);
}
return $matrix;
}
sub proc_net_dev_stats {
my $interface = shift;
my ($stdout, $stderr) = ('', '');
# Capture /proc/net/dev twice with $interval seconds in between
my $first_read = read_file('/proc/net/dev');
if (!defined($first_read)) {
$bb->color_line( 'yellow',
"Couldn't read /proc/net/dev initially!");
return ($stdout, $stderr);
}
sleep($interval);
my $second_read = read_file('/proc/net/dev');
if (!defined($second_read)) {
$bb->color_line( 'yellow',
"Couldn't read /proc/net/dev for a second time!");
return ($stdout, $stderr);
}
# Parse them into an array of arrays
my $first_matrix = parse_proc_net_dev($first_read);
my $second_matrix = parse_proc_net_dev($second_read);
my $result_matrix = [];
# Then calculate the difference between all numerical values
for (my $i = 0; $i < @$first_matrix; $i++) {
$result_matrix->[$i] = [];
for (my $j = 0; $j < @{$first_matrix->[$i]}; $j++) {
my $a = $first_matrix->[$i][$j];
my $b = $second_matrix->[$i][$j];
if ($a =~ /^\d+$/ and $b =~ /^\d+$/) {
$result_matrix->[$i][$j] = ($b - $a)/$interval;
} elsif ($a eq $b) {
$result_matrix->[$i][$j] = $a;
} else {
$bb->color_line( 'yellow',
'Inconsistency found in /proc/net/dev: '.
"'$a' not equal '$b', but both are not a ".
"number either.");
}
}
}
foreach my $line (@$result_matrix) {
my $line_interface = $line->[0];
$line_interface =~ s/:$//;
my $if_stdout = '';
foreach my $type (sort keys %netstat_field) {
$if_stdout .=
$type .
': ' .
$line->[$netstat_field{$type}] .
"\n";
}
$if_cache{"netstat+$line_interface"} =
[ $if_stdout, $stderr, 'netstat', $line_interface ];
$stdout .= $if_stdout;
$if_cache{"netstat"} =
[ $stdout, $stderr, 'netstat' ];
return @{$if_cache{"netstat+$interface"}};
}
sub check_if_state {
my ($interface, $state, $color) = @_;
my ($stdin, $stdout, $stderr, @cmd, $exitcode);
# Special casing
if (exists $special_case{$state}) {
$state = $special_case{$state};
} elsif ($state eq 'DOWN' and not $ip_bin) {
$state = 'not UP';
}
# Generic special cases (sic!)
$state =~ s{ (\d+) baseT $ }{Speed: ${1}Mb/s}x;
$state =~ s{ ^ \d+ Mb/s $ }{Speed: $&}x;
# Some checks need ethtool
if ($state =~ /Duplex:|Speed:|Auto-negotiation:|Port:|Link detected:/) {
($stdout, $stderr, @cmd) =
(@{$if_cache{"ethtool+$interface"}}, '(cached)');
return 0 if (defined($stderr) and
$stderr =~ /No such device/);
} else {
if ($ethtool_bin) {
@cmd = ('ethtool', $interface);
} else {
$bb->color_line(
'yellow',
"State '$state' (on '$interface') can only be queried ".
"with ethtool, but ethtool seems not available.\n");
}
run(\@cmd, \$stdin, \$stdout, \$stderr);
$exitcode = $? >> 8;
$if_cache{"ethtool+$interface"} = [ $stdout, $stderr, @cmd ];
# Checks against /proc/net/dev (aka netstat without calling a program)
} elsif ($state =~ /^[TR]X-(OK|ERR)[:<>=\s]/) {
if (exists $if_cache{"netstat+$interface"}) {
($stdout, $stderr, @cmd) =
(@{$if_cache{"netstat+$interface"}}, '(cached)');
} else {
if (-r '/proc/net/dev') {
($stdout, $stderr) = &proc_net_dev_stats($interface);
} else {
$bb->color_line(
'yellow',
"/proc/net/dev either does not exist or is not readable.\n");
}
}
} else {
# States being able to read with ip or ifconfig
if (exists $if_cache{$interface}) {
($stdout, $stderr, @cmd) =
(@{$if_cache{$interface}}, '(cached)');
return 0 if (defined($stderr) and
$stderr =~ /Cannot find device|Device not found/);
} else {
if ($ip_bin) {
# Safeguard because we have to use "sh -c ..."
croak "Bad interface name '$interface'"
if $interface !~ /^[-_a-zA-Z0-9]*$/;
@cmd = ('sh', '-c',
"ip link show dev $interface && ip address show dev $interface");
} elsif ($ifconfig_bin) {
@cmd = ('ifconfig', $interface);
} else {
croak 'Assertion failed: ip or ifconfig present';
}
run(\@cmd, \$stdin, \$stdout, \$stderr);
$exitcode = $? >> 8;
$if_cache{$interface} = [ $stdout, $stderr, @cmd ];
}
}
if (defined($stderr) and $stderr ne '') {
if ($stderr =~ /Cannot find device|Device not found|No such device/) {
$bb->color_line(
'yellow',
"Interface '$interface' configured, but not found. Skipping.\n");
return 0;
}
# Ignore all "Operation not permitted" warnings as long as we
# get all the information we wanted.
unless ($stderr =~ /Operation not permitted/) {
$bb->color_line(
'yellow',
"Calling '".join(' ', @cmd)."' caused a warning: $stderr");
}
}
if ($exitcode) {
$bb->color_line(
'yellow',
"Querying $interface exited with $exitcode.\n");
}
if (defined($stdout) and $stdout ne '') {
if ($state =~ /^not\s(.*)$/) {
$state = $1;
if ($stdout =~ /\b\Q$state\E\b/) {
$bb->color_line($color || 'yellow',
"$interface is $state (but shouldn't)\n");
} else {
$bb->color_line('green',
"$interface isn't $state\n");
}
} elsif ($state =~ / ^ ([^<>=]*?) \s* ( [<>=] | [<>=]= ) \s* ([^<>=]*?) $ /x) {
my ($key, $comparison, $threshold) = ($1, $2, $3);
$key =~ s/:$//;
if ($stdout =~ / \b \Q$key\E :? \s* ( [-+]? \d+(?:\.\d+)? ) \b /x) {
my $value = $1;
$comparison = '==' if $comparison eq '=';
if (eval('$value '.$comparison.' '.$threshold)) {
$bb->color_line('green',
"$key on $interface ($value) is $comparison $threshold\n");
} else {
$bb->color_line($color || 'yellow',
"$key on $interface ($value) is NOT $comparison $threshold\n");
}
} else {
$bb->color_line($color || 'yellow',
"Can't find '$key' for $interface to check its value\n$stdout\n\n");
}
} else {
if ($stdout !~ /\b\Q$state\E\b/) {
$bb->color_line($color || 'yellow',
"$interface isn't $state (but should)\n");
} else {
$bb->color_line('green',
"$interface is $state\n");
}
}
} else {
$bb->color_line(
'yellow',
"Can't check $state on $interface: Querying $interface resulted in no output.\n");
}
}