[LARTC] Perl script to adjust default routing on 2 Net connections

[whit@xxxxxxxxxxxxx (Whit Blauvelt)]

More fixed. Simpler logic on appending. Deletes only if append has worked.
An allows setting the number of pings to try and the number of those that
must be good.

Whit

--- cut ---
#!/usr/local/bin/perl

# checkroutes.pl version 0.06, 18 Feb. 2002, whit@transpect.com
# Extends stock Nano-Howto setup with upstream route accessibility checking
# See http://www.linuxvirtualserver.org/~julian/nano.txt and patches at
# http://www.linuxvirtualserver.org/~julian/#routes
# (if not using Julian's patchs, remove "proto static" occurrences below)

# Run from cron (set with "crontab -e")
# example: "0-59/2 * * * * /path/to/checkroutes.pl" runs this every 2 minutes

# Best IPs to test for general use may be last IPs at ISPs before routing out to Net
# Best IP to test if a single remote site is most important is that site's

# If perl not at /usr/local/bin/perl change first line to point to it

# Before running install Net::Ping from http://freeware.roobik.com/netping/
# (untar, cd to directory, "perl Makefile.PL; make; make install")

use Net::Ping;

# User settings
# _____________

$ip	= "/usr/sbin/ip";	# Location of "ip" on system

$gw1 	= "";	# Gateway 1 IP
$dev1	= "";		# Device (e.g., eth1)
$tip1	= "";	# Upstream IP to test
$src1	= "";	# Source address for outgoing packets
$wei1	= "1";			# Weight

$gw2	= "";	# Gateway 2 IP
$dev2	= "";		# Device (e.g., eth2)
$tip2	= "";	# Upstream IP to test
$src2	= "";	# Source address for outgoing packets
$wei2	= "1";			# Weight

$pings	= "1";			# Number of pings to send
$good	= "1";			# Number of pings that must be good

$tab	= "222";		# Table to set routes in

$logfile = "/var/log/checkroutes.log"; # File to log messages to 

# create timestamp for log
# ________________________

sub TimeStamp {

	# subroutine to create a "nice" looking timestamp
	# that doesn't rely on the system's 'date' command

	my @days = ('Sun','Mon','Tue','Wed','Thu','Fri','Sat');
	my @months = ('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep',
		'Oct','Nov','Dec');

	my ($sec,$min,$hour,$dom,$mon,$year,$wday,$yday,$isd) = localtime(time);
	my $timestamp = sprintf("%3s %3s %02d %4d  %02d:%02d:%02d", $days[$wday],
		$months[$mon], $dom, $year+1900, $hour, $min, $sec);

	return $timestamp;
} 

# be sure routes are set via appropriate gateways to test IPs 
# ___________________________________________________________

$checkro = `$ip ro ls`;
if (!($checkro =~ /$tip1/)) {
	system ("$ip ro add to $tip1 via $gw1 src $src1 proto static");
}
if (!($checkro =~ /$tip2/)) {
	system ("$ip ro add to $tip2 via $gw2 src $src2 proto static");
}

# test if $gw1 and/or $gw2 currently in table $tab
# ________________________________________________

$checkgw = qx/$ip ro ls tab $tab/;

if ($checkgw =~ /$gw1/) {
	$check1 = 1;
} else {
	$check1 = 0;
}

if ($checkgw =~ /$gw2/) {
	$check2 = 1;
} else {
	$check2 = 0;
}

# ping the test IPs $tip1 and $tip2
# _________________________________

$i=0;
$p = Net::Ping->new("icmp");
while ($i < $pings) {
	if ($p->ping($tip1)) {
		$ping1++;
	}
	$i++;
}
$p->close();

if ($ping1 >= $good) {
	$live1 = 1;
} else {
	$live1 = 0;
}

$i=0;
$p = Net::Ping->new("icmp");
while ($i < $pings) {
	if ($p->ping($tip2)) {
		$ping2++;
	}
	$i++;
}
$p->close();

if ($ping2 >= $good) {
	$live2 = 1;
} else {
	$live2 = 0;
}

# If the current default in table $tab does not match the ping results then
# if only one route's test IP is pingable change the default to that route
# or if both test IPs are pingable change the default to use both
# or if neither test IPs are pingable change the default to use both 
# (might as well continue to try them, if we're not going anywhere anyway)
# _________________________________________________________________________

# append new default route
# ________________________

if (($check1 != $live1)||($check2 != $live2)) {
	if (($live1 == 1)&&($live2 == 0)) {
		system ("$ip ro ap default tab $tab proto static via $gw1 dev $dev1");
	} elsif (($live1 == 0)&&($live2 == 1)) {
		system ("$ip ro ap default tab $tab proto static via $gw2 dev $dev2");
	} else {
		system ("$ip ro ap default tab $tab proto static nexthop via $gw1 dev $dev1 weight $wei1 nexthop via $gw2 dev $dev2 weight $wei2");
	}
}

# delete and flush old default route if second has been appended
# ______________________________________________________________

$checkdup = qx/$ip ro ls tab $tab/;
if ($checkdup =~ /default.*default/s) {
	system ("$ip ro del default tab $tab");
	system ("$ip ro flush cache");
}

# log
# ___

if (($live1 == 1)&&($live2 == 1)) {
	$log = "both UP";
} elsif (($live1 == 0)&&($live2 == 0)) {
	$log = "both DOWN (set UP)";
} elsif (($live1 == 1)&&($live2 == 0)) {
	$log = "$gw1 up, $gw2 DOWN";
} elsif (($live1 == 0)&&($live2 == 1)) {
	$log = "$gw2 up, $gw1 DOWN";
}

open(LOG, ">>$logfile");
print LOG &TimeStamp . " - $log\n";
close(LOG);