#!/usr/bin/perl
#
# $Header: /usr/machine/nat/RCS/nat,v 1.6 2002/06/22 01:16:00 sanpei Exp sanpei $
#
$DEBUG = 0;
#
# local settings
#
$POOLING_TIME = 60; #seconds)
$WAN_INTERFACE = "ed1";
$NAT_DIR = "/usr/machine/nat";
$HEADER = "${NAT_DIR}/header.html";
$MIDDLE = "${NAT_DIR}/middle.html";
$FOOTER = "${NAT_DIR}/footer.html";
$MY_HOME = "my-home.html";
$MY_HOME_HTML = "/tmp/$MY_HOME";
$FTP_COMMAND = "/tmp/put_html";
#
#  for FreeBSD settings
#
$DHCPC = "/usr/local/sbin/dhcpc";
$DHCPC_PID = "/var/run/dhcpc.$WAN_INTERFACE.pid";
$DHCPC_START = "$DHCPC $WAN_INTERFACE";
$PS = "/bin/ps";
$PS_OPT = "axuww";
$IFCONFIG = "/sbin/ifconfig";
$PING_BIN = "/sbin/ping";
$CHECK_HOST = "219.117.164.1" ; # www.seaple.icc.ne.jp
$KILLALL = "/usr/bin/killall";
#
# initialize  variable
#
$old_wan_ip = "0.0.0.0";

while (1) {
    &check_wan_ip;
    &check_dhcpc;
    sleep($POOLING_TIME);
}
###################
#
#  check wan_ip
#
sub check_wan_ip {
    $current_wan_ip = &ischange_wan_ip;
    if (! $current_wan_ip) {
	return 0;
    } else {
	system("/usr/local/sbin/ddup --host lily.homedns.org --ip $current_wan_ip");
	&recreate_html($current_wan_ip);
	$old_wan_ip = $current_wan_ip;
	return 0;
    }
}
#
#  ischange_wan_ip
#    return wan_ip_address (if wan_interface address was changed)
#           0              (if it was not changed
#                              or still not get wan ip address via dhcp)
#
sub ischange_wan_ip {
    my($current_wan_ip);
    $current_wan_ip = &get_wan_ip($WAN_INTERFACE);
    if ($current_wan_ip =~ /^10.0/) {
	return 0;
    } elsif ($current_wan_ip eq $old_wan_ip) {
	return 0;
    } else {
	return $current_wan_ip;
    }
}

sub get_wan_ip {
    local($WAN_INTERFACE) = @_;
    local($wan_ip, $d1, $d3);
    open(IFCONFIG, "$IFCONFIG $WAN_INTERFACE |");
    while (<IFCONFIG>) {
	chonp;
	if ($DEBUG) {
	    print "$_\n";
	}
	if (/inet/) {
	    ($d1, $wan_ip, $d3) = split(/ /, $_, 3);
	}
    }
    close(IFCONFIG);
    if ($DEBUG) {
	print "$wan_ip\n";
    }
    if ($DEBUG) {
	return time;
    } else {
	return $wan_ip;
    }
}
    
################
#
# check dhcpc
#
sub check_dhcpc {
    if (&isconnect_server == 0) {
	&killdhcpc;
    }
    if (&isstaydhcpc) {
	return 0;
    } else {
	&restart_dhcpc;
    }
}
sub isconnect_server {
    if (system("${PING_BIN} -c 1 ${CHECK_HOST} > /dev/null 2>&1") == 0) {
        return 1;
    } else {
        return 0;
    }
}
sub killdhcpc {
    system("${KILLALL} dhcpc");
    system("${IFCONFIG} ${WAN_INTERFACE} down");
    system("${IFCONFIG} ${WAN_INTERFACE} delete");
}
sub restart_dhcpc {
    system($DHCPC_START);
}
sub isstaydhcpc {
    open(FP, "< $DHCPC_PID");
    $dhcpc_pid = <FP>;
    close(FP);
    open (PS, "$PS $PS_OPT |");
    while (<PS>) {
	($dummy1, $pid, $dummy2) = split(/[ \t\n]+/, $_, 3);
	if ($_ =~ /dhcpc/ && $_ =~ /$WAN_INTERFACE/ 
	    && $pid == $dhcpc_pid) {
	    close(PS);
	    return 1;
	}
    }
    close(PS);
    return 0;
}	
###################
#
# recreate html
#
sub recreate_html {
    my($wan_ip) = @_;
    open(HOME, "> $MY_HOME_HTML");
    &put_file_to($HEADER);

    if (0) {
	print HOME "<a href=\"http://$wan_ip/\">\n";
	print HOME "$wan_ip\n";
	print HOME "</a>\n";
    } else {
	print HOME "[1]";
	print HOME "$wan_ip\n";
    }

    &put_file_to($MIDDLE);

    print HOME `date`;
    print HOME "\n";

    &put_file_to($FOOTER);
    close(HOME);
    &create_ftp_command;
}
sub put_file_to {
    my($file) = @_;
    open(FP_TMP, "< $file");
    open(FP2, ">> /tmp/zz");
    while (<FP_TMP>) {
	print HOME $_;
	print FP2 $_;
    }
    close(FP);
    close(FP2);
}
sub create_ftp_command {
    open(fp, "> $FTP_COMMAND");
    print fp <<"---";
#!/bin/csh -f
cd /tmp
setenv HOME /root
ftp www.seaple.icc.ne.jp << _EOF_ >&! ftp.log
cd public_html
bin
---

    print fp "put $MY_HOME\n";
    print fp <<"---";
quit
_EOF_
---
    close(fp);
    system("chmod +x ". $FTP_COMMAND);
    system($FTP_COMMAND);
}