#!/usr/bin/perl
# uidentd 1.2.1 - an auth/ident server implementing most of RFC 1413
#
# Copyright (C) 2002-2006 Amir Malik <a@unoc.net>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
#
# For more information, see: http://www.unoc.net/a/uidentd/
#
# ChangeLog
#   - 1.0    initial release of IPv6-only version
#   - 1.1    added IPv4 and multiple query support
#   - 1.2    update header
#   - 1.2.1  send CRLFs as per RFC; thanks to Thomas Zehetbauer

my $MAXQUERIES = 5; # max queries per connection
my $MAXTIME = 10; # max seconds per connection

$SIG{'ALRM'} = sub { exit };
alarm($MAXTIME); # die on blocking sockets
$| = 1;
my($port1,$port2);
my $i;

while(<STDIN>) {
  $i++;
  chomp(my $line = $_);
  $line =~ s/\s//g;
  ($port1,$port2) = split(/,/,$line);
  if(!$port1 || !$port2) {
    print "$port1 , $port2 : ERROR : UNKNOWN-ERROR\r\n";
    exit;
  }
  my $unam = getports("tcp6"); # ipv6 check
  if($unam) {
    print "$port1 , $port2 : USERID : UNIX : $unam\r\n";
  } else {
    $unam = getports("tcp"); # ipv4 check
    if($unam) {
      print "$port1 , $port2 : USERID : UNIX : $unam\r\n";
    } else {
      print "$port1 , $port2 : ERROR : UNKNOWN-ERROR\r\n";
    }
  }
  if($i >= $MAXQUERIES) {
    exit;
  }
}

sub getports {
  my($file) = $_[0];
  open(PROC_TCP,"</proc/net/$file");
  my $unam;
  while(my $proc_tcp = <PROC_TCP>) {
    my($laddr,$lport,$raddr,$rport,$uid) = $proc_tcp =~ /^\s*\S+\: (\S+)\:(\S+)\s+(\S+)\:(\S+)\s+\S+\s+\S+\:\S+\s+\S+\:\S+\s+\S+\s+(\S+)/;
    $lport = hex($lport);
    $rport = hex($rport);
    if($port1 == $lport && $port2 == $rport) {
      ($unam) = getpwuid($uid);
    }
  }
  close(PROC_TCP);
  return $unam;
}