#!/usr/local/bin/perl
# 
# Filename: ip-up
#
# Code by Lindsay Haisley, FMP Computer Serivces, fmouse@fmp.com
# Terms of the GNU GENERAL PUBLIC LICENSE apply
# see <http://www.gnu.org/copyleft/gpl.html>
#
# ip-up for use with pppd and mgetty 0.99 with Auto_PPP.  This script allows
# the setting of proxyarp for a ppp connection on a per-user basis -
# something which can't be done with Auto_PPP since pppd always has a real
# and effective uid of root if invoked with the Auto_PPP facility in mgetty
# 0.99.
#
# To use the script, create the file /etc/ppp/proxyarp with lines in the
# format:
#
# username	+|-
#
# If a "+" follows the username, proxy arp will be set for a login by
# username.  If a "-" follows the username, any proxy arp entry for a login
# by username will be removed.  The script can thus be used to remove proxy
# arp for specific users if proxyarp is set globally, or to add it if
# proxyarp is not set globally.


$ENV{'PATH'} = "/bin:/usr/bin:/sbin:/usr/sbin";
$piddir = "/var/run";

# Obtain local hardware address
open (L, "ifconfig|grep HWaddr|");
($foo, $hw_addr) = split(/HWaddr\ /, <L>);
chop $hw_addr;

# Obtain the terminal
$ARGV[1] =~ /\/dev\/(.+)$/;
$tty = $1;
$iface = $ARGV[0];

# Grab the assigned remote IP
$ip = $ARGV[4];

# Determine the user
open (M, "who|grep $tty|");
($who, $foo) = split (/[ \t]+/, <M>);

# We now know who, now we can find out what

open (PAFILE, "/etc/ppp/proxyarp");
while (<PAFILE>) {
	($user, $status) = split;
	if ($status =~ /\n/) {chop $status;}
	last if $user eq $who;
}

exit if $user ne $who; 	# Not in list - as you were

if ($status eq "+") {`arp -s $ip $hw_addr pub`;}
if ($status eq "-") { `arp -d $ip pub`; }

# Now let's deal with timeouts
# ---------------------------------------
# Create a session file
# Get pid
open (PIDFILE, "${piddir}/${iface}.pid");
$pid = <PIDFILE>;
chomp $pid;
close (PIDFILE);
$time = time;

# Get packet traffic stats
open (NETSTAT, "/proc/net/dev");
$trash = <NETSTAT>;
$trash = <NETSTAT>;
$time = time;
while (<NETSTAT>) {
	($ifname, $rpackets, $rerrs, $rdrop, $rfifo, $rframe, \
$xpackets, $xerrs, $xdrop, $xfifo, $xcolls, $xcarrier) = split;
	last if $ifname eq $iface.":";
}
open (SESSION, ">/var/run/$iface.session");
print SESSION "$who\t$pid\t$time\t$time\t$rpackets\t$xpackets";
close (SESSION);