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|
#!/usr/bin/perl
#
# Module: vyatta-dns-forwarding.pl
#
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# 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.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2008 Vyatta, Inc.
# All Rights Reserved.
#
# Author: Mohit Mehta
# Date: August 2008
# Description: Script to glue Vyatta CLI to dnsmasq daemon
#
# **** End License ****
#
use lib "/opt/vyatta/share/perl5/";
use VyattaConfig;
use VyattaMisc;
use Getopt::Long;
use strict;
use warnings;
my $dnsforwarding_init = '/etc/init.d/dnsmasq';
my $dnsforwarding_conf = '/etc/dnsmasq.conf';
sub dnsforwarding_restart {
system("$dnsforwarding_init restart >&/dev/null");
print "Setting up DNS forwarding.\n";
}
sub dnsforwarding_stop {
system("$dnsforwarding_init stop >&/dev/null");
print "Stopping DNS forwarding.\n";
}
sub dnsforwarding_get_constants {
my $output;
my $date = `date`;
chomp $date;
$output = "#\n# autogenerated by vyatta-dns-forwarding.pl on $date\n#\n";
return $output;
}
sub dnsforwarding_get_values {
my $output = '';
my $config = new VyattaConfig;
$config->setLevel("service dns forwarding");
my @ignore_interfaces = $config->returnValues("ignore-interface");
if ($#ignore_interfaces >= 0) {
foreach my $interface (@ignore_interfaces) {
$output .= "except-interface=$interface\n";
}
}
my $cache_size = $config->returnValue("cache-size");
if (defined $cache_size) {
$output .= "cache-size=$cache_size\n";
}
return $output;
}
sub dnsforwarding_write_file {
my ($config) = @_;
open(my $fh, '>', $dnsforwarding_conf) || die "Couldn't open $dnsforwarding_conf - $!";
print $fh $config;
close $fh;
}
sub check_nameserver {
my $cmd = `grep nameserver /etc/resolv.conf|wc -l`;
return $cmd;
}
sub check_system_nameserver {
my $num_all_nameservers = `grep nameserver /etc/resolv.conf|wc -l`;
my $num_dhcp_nameservers = `grep nameserver /etc/resolv.conf| grep vyatta_update_resolv|wc -l`;
return ($num_all_nameservers - $num_dhcp_nameservers);
}
sub check_dhcp_nameserver {
my $intf = shift;
my $cmd = `grep nameserver /etc/resolv.conf.dhclient-new-$intf|wc -l`;
return $cmd;
}
sub is_dhcp_enabled {
my $intf = shift;
my $config = new VyattaConfig;
if ($intf =~ m/^eth/) {
if ($intf =~ m/(\w+)\.(\d+)/) {
$config->setLevel("interfaces ethernet $1 vif $2");
} else {
$config->setLevel("interfaces ethernet $intf");
}
} elsif ($intf =~ m/^br/) {
$config->setLevel("interfaces bridge $intf");
} else {
#
# currently we only support dhcp on ethernet
# and bridge interfaces.
#
return 0;
}
my @addrs = $config->returnOrigValues("address");
foreach my $addr (@addrs) {
if (defined $addr && $addr eq "dhcp") {
return 1;
}
}
return 0;
}
sub check_dhcp_interface {
my $interface = shift;
if (!is_dhcp_enabled($interface)) {
print "$interface is not using DHCP to get an IP address\n";
return 0;
}
if (-e "/var/run/vyatta/dhclient/dhclient_release_$interface") {
# dhcp released for the interface
print "DHCP lease for $interface has been released.\n";
print "Renew lease for $interface before setting this parameter.\n";
return 0;
}
return 1;
}
#
# main
#
my ($update_dnsforwarding, $stop_dnsforwarding, $system_nameserver, $dhcp_interface, $dhcp_interface_nameserver);
GetOptions("update-dnsforwarding!" => \$update_dnsforwarding,
"stop-dnsforwarding!" => \$stop_dnsforwarding,
"system-nameserver!" => \$system_nameserver,
"dhcp-interface-nameserver=s" => \$dhcp_interface_nameserver,
"dhcp-interface=s" => \$dhcp_interface);
if (defined $system_nameserver) {
my $system_nameserver_exists = check_system_nameserver();
if ($system_nameserver_exists < 1){
print "Warning: No DNS servers set in system to forward queries.\n";
}
}
if (defined $dhcp_interface_nameserver) {
my $dhcp_interface_nameserver_exists = check_dhcp_nameserver($dhcp_interface_nameserver);
if ($dhcp_interface_nameserver_exists < 1){
print "Warning: No DNS servers received from DHCP server for $dhcp_interface_nameserver.\n";
}
}
if (defined $dhcp_interface) {
if (!check_dhcp_interface($dhcp_interface)){
exit 1;
}
}
if (defined $update_dnsforwarding) {
my $config;
my $vyatta_config = new VyattaConfig;
$vyatta_config->setLevel("service dns forwarding");
my $use_system_nameservers = $vyatta_config->exists("system");
my @use_dhcp_nameservers = $vyatta_config->returnValues("dhcp");
my @use_nameservers = $vyatta_config->returnValues("name-server");
if (!(defined $use_system_nameservers) && (@use_dhcp_nameservers == 0) && (@use_nameservers == 0)) {
my $nameserver_exists = check_nameserver();
if ($nameserver_exists < 1){
print "Warning: No DNS servers ('system set' or 'dhcp received') to forward queries.\n";
}
}
$config = dnsforwarding_get_constants();
$config .= dnsforwarding_get_values();
dnsforwarding_write_file($config);
dnsforwarding_restart();
}
if (defined $stop_dnsforwarding) {
dnsforwarding_stop();
}
exit 0;
# end of file
|
