#!/usr/bin/perl

use strict;
use warnings;
use PVE::SafeSyslog;
use POSIX ":sys_wait_h";
use Fcntl ':flock';
use Getopt::Long;
use Time::HiRes qw (gettimeofday);
use PVE::Tools qw(dir_glob_foreach file_read_firstline);
use PVE::INotify;
use PVE::Cluster qw(cfs_read_file);
use PVE::RPCEnvironment;
use PVE::CLIHandler;
use PVE::Firewall;

use base qw(PVE::CLIHandler);

my $pve_firewall_pidfile = "/var/run/pve-firewall.pid";

$SIG{'__WARN__'} = sub {
    my $err = $@;
    my $t = $_[0];
    chomp $t;
    print "$t\n";
    syslog('warning', "WARNING: %s", $t);
    $@ = $err;
};

initlog('pve-firewall');

$ENV{'PATH'} = '/sbin:/bin:/usr/sbin:/usr/bin';

die "please run as root\n" if $> != 0;

PVE::INotify::inotify_init();

my $rpcenv = PVE::RPCEnvironment->init('cli');

$rpcenv->init_request();
$rpcenv->set_language($ENV{LANG});
$rpcenv->set_user('root@pam');

my $commandline = [$0, @ARGV];

$0 = "pve-firewall";

sub restart_server {
    my ($waittime) = @_;

    syslog('info', "server shutdown (restart)");

    $ENV{RESTART_PVE_FIREWALL} = 1;

    sleep($waittime) if $waittime; # avoid high server load due to restarts

    exec (@$commandline);
    exit (-1); # never reached?
}

sub cleanup {
    unlink "$pve_firewall_pidfile.lock";
    unlink $pve_firewall_pidfile;
}

sub lockpidfile {
    my $pidfile = shift;
    my $lkfn = "$pidfile.lock";

    if (!open (FLCK, ">>$lkfn")) {
	my $msg = "can't aquire lock on file '$lkfn' - $!";
	syslog ('err', $msg);
	die "ERROR: $msg\n";
    }

    if (!flock (FLCK, LOCK_EX|LOCK_NB)) {
	close (FLCK);
        my $msg = "can't aquire lock '$lkfn' - $!";
	syslog ('err', $msg);
	die "ERROR: $msg\n";
    }
}

sub writepidfile {
    my $pidfile = shift;

    if (!open (PIDFH, ">$pidfile")) {
	my $msg = "can't open pid file '$pidfile' - $!";
	syslog ('err', $msg);
	die "ERROR: $msg\n";
    } 
    print PIDFH "$$\n";
    close (PIDFH);
}

my $restart_request = 0;
my $next_update = 0;

my $cycle = 0; 
my $updatetime = 10;

my $initial_memory_usage;

sub run_server {
    my ($param) = @_;

    # try to get the lock
    lockpidfile($pve_firewall_pidfile);

    # run in background
    my $spid;

    my $restart = $ENV{RESTART_PVE_FIREWALL};

    delete $ENV{RESTART_PVE_FIREWALL};

    PVE::Cluster::cfs_update();
    
    PVE::Firewall::init();

    if (!$param->{debug}) {
	open STDIN,  '</dev/null' || die "can't read /dev/null";
	open STDOUT, '>/dev/null' || die "can't write /dev/null";
    }

    if (!$restart && !$param->{debug}) {
	$spid = fork();
	if (!defined ($spid)) {
	    my $msg =  "can't put server into background - fork failed";
	    syslog('err', $msg);
	    die "ERROR: $msg\n";
	} elsif ($spid) { # parent
	    exit (0);
	}
    } 

    writepidfile($pve_firewall_pidfile);

    open STDERR, '>&STDOUT' || die "can't close STDERR\n";
 
    $SIG{INT} = $SIG{TERM} = $SIG{QUIT} = sub { 
	syslog('info' , "server closing");

	$SIG{INT} = 'DEFAULT';

	# wait for children
	1 while (waitpid(-1, POSIX::WNOHANG()) > 0);
	
	syslog('info' , "clear firewall rules");
	eval { PVE::Firewall::remove_pvefw_chains(); die "STOP";};
	warn $@ if $@;

	cleanup();

	exit (0);
    };

    $SIG{HUP} = sub {
	# wake up process, so this forces an immediate firewall rules update
	syslog('info' , "received signal HUP (restart)");
	$restart_request = 1;
    };

    if ($restart) {
	syslog('info' , "restarting server");
    } else {
	syslog('info' , "starting server");
    }

    for (;;) { # forever

	eval {

	    local $SIG{'__WARN__'} = 'IGNORE'; # do not fill up logs

	    $next_update = time() + $updatetime;

	    my ($ccsec, $cusec) = gettimeofday ();
	    eval {
		PVE::Cluster::cfs_update();
		PVE::Firewall::update();
	    };
	    my $err = $@;

	    if ($err) {
		syslog('err', "status update error: $err");
	    }

	    my ($ccsec_end, $cusec_end) = gettimeofday ();
	    my $cptime = ($ccsec_end-$ccsec) + ($cusec_end - $cusec)/1000000;

	    syslog('info', sprintf("firewall update time (%.3f seconds)", $cptime))
		if ($cptime > 5);

	    $cycle++;

	    my $mem = PVE::ProcFSTools::read_memory_usage();

	    if (!defined($initial_memory_usage) || ($cycle < 10)) {
		$initial_memory_usage = $mem->{resident};
	    } else {
		my $diff = $mem->{resident} - $initial_memory_usage;
		if ($diff > 5*1024*1024) {
		    syslog ('info', "restarting server after $cycle cycles to " .
			    "reduce memory usage (free $mem->{resident} ($diff) bytes)");
		    restart_server();
		}
	    }

	    my $wcount = 0;
	    while ((time() < $next_update) && 
		   ($wcount < $updatetime) && # protect against time wrap
		   !$restart_request) { $wcount++; sleep (1); };

	    restart_server() if $restart_request;
	};

	my $err = $@;
    
	if ($err) {
	    syslog ('err', "ERROR: $err");
	    restart_server(5);
	    exit (0);
	}
    }
}

__PACKAGE__->register_method ({
    name => 'start',
    path => 'start',
    method => 'POST',
    description => "Start the Proxmox VE firewall service.",
    parameters => {
    	additionalProperties => 0,
	properties => {
	    debug => {
		description => "Debug mode - stay in foreground",
		type => "boolean",
		optional => 1,
		default => 0,
	    },
	},
    },
    returns => { type => 'null' },

    code => sub {
	my ($param) = @_;

	run_server($param);

	return undef;
    }});

__PACKAGE__->register_method ({
    name => 'stop',
    path => 'stop',
    method => 'POST',
    description => "Stop firewall. This removes all Proxmox VE related iptable rules. The host is unprotected afterwards.",
    parameters => {
    	additionalProperties => 0,
	properties => {},
    },
    returns => { type => 'null' },

    code => sub {
	my ($param) = @_;

	my $pid = int(PVE::Tools::file_read_firstline($pve_firewall_pidfile) || 0);

	if ($pid) {
	    if (PVE::ProcFSTools::check_process_running($pid)) {
		kill(15, $pid); # send TERM signal
		# give max 5 seconds to shut down
		for (my $i = 0; $i < 5; $i++) {
		    last if !PVE::ProcFSTools::check_process_running($pid);
		    sleep (1);
		}
       
		# to be sure
		kill(9, $pid); 
		waitpid($pid, 0);
	    }
	    if (-f $pve_firewall_pidfile) {
		# try to get the lock
		lockpidfile($pve_firewall_pidfile);
		cleanup();
	    }
	}

	return undef;
    }});

__PACKAGE__->register_method ({
    name => 'status',
    path => 'status',
    method => 'GET',
    description => "Get firewall status.",
    parameters => {
    	additionalProperties => 0,
	properties => {},
    },
    returns => { 
	type => 'object',
	additionalProperties => 0,
	properties => {
	    status => {
		type => 'string',
		enum => ['unknown', 'stopped', 'active'],
	    },
	    changes => {
		description => "Set when there are pending changes.",
		type => 'boolean',
		optional => 1,
	    }
	},
    },
    code => sub {
	my ($param) = @_;

	local $SIG{'__WARN__'} = 'DEFAULT'; # do not fill up syslog

	my $code = sub {

	    my $pid = int(PVE::Tools::file_read_firstline($pve_firewall_pidfile) || 0);
	    my $running = PVE::ProcFSTools::check_process_running($pid);

	    my $status = $running ? 'active' : 'stopped';

	    my $res = { status => $status };
	    if ($status eq 'active') {
		my ($ruleset, $ipset_ruleset) = PVE::Firewall::compile();

		my (undef, undef, $ipset_changes) = PVE::Firewall::get_ipset_cmdlist($ipset_ruleset);
		my (undef, $ruleset_changes) = PVE::Firewall::get_ruleset_cmdlist($ruleset);
	      
		$res->{changes} = ($ipset_changes || $ruleset_changes) ? 1 : 0;
	    }

	    return $res;
	};

	return PVE::Firewall::run_locked($code);
    }});

__PACKAGE__->register_method ({
    name => 'compile',
    path => 'compile',
    method => 'POST',
    description => "Compile and print firewall rules. This is useful for testing.",
    parameters => {
    	additionalProperties => 0,
	properties => {},
    },
    returns => { type => 'null' },

    code => sub {
	my ($param) = @_;

	local $SIG{'__WARN__'} = 'DEFAULT'; # do not fill up syslog

	my $code = sub {
	    my ($ruleset, $ipset_ruleset) = PVE::Firewall::compile();

	    my (undef, undef, $ipset_changes) = PVE::Firewall::get_ipset_cmdlist($ipset_ruleset, 1);
	    my (undef, $ruleset_changes) = PVE::Firewall::get_ruleset_cmdlist($ruleset, 1);
	    if ($ipset_changes || $ruleset_changes) {
		print "detected changes\n";
	    } else {
		print "no changes\n";
	    }
	};

	PVE::Firewall::run_locked($code);

	return undef;
    }});

my $nodename = PVE::INotify::nodename();

my $cmddef = {
    start => [ __PACKAGE__, 'start', []],
    stop => [ __PACKAGE__, 'stop', []],
    compile => [ __PACKAGE__, 'compile', []],
    status => [ __PACKAGE__, 'status', [], undef, sub {
	my $res = shift;
	if ($res->{changes}) {
	    print "Status: $res->{status} (pending changes)\n";
	} else {
	    print "Status: $res->{status}\n";
	}
    }],
 };

my $cmd = shift;

PVE::CLIHandler::handle_cmd($cmddef, $0, $cmd, \@ARGV, undef, $0);

exit (0);

__END__

=head1 NAME
                                          
pve-firewall - PVE Firewall Daemon

=head1 SYNOPSIS

=include synopsis

=head1 DESCRIPTION

This service updates iptables rules periodically.

=include pve_copyright