# Net::Config.pm

#

# Copyright (c) 2000 Graham Barr <gbarr@pobox.com>. All rights reserved.

# This program is free software; you can redistribute it and/or

# modify it under the same terms as Perl itself.

package Net::Config;

require Exporter;

use vars qw(@ISA @EXPORT %NetConfig $VERSION $CONFIGURE $LIBNET_CFG);

use Socket qw(inet_aton inet_ntoa);

use strict;

@EXPORT  = qw(%NetConfig);

@ISA     = qw(Net::LocalCfg Exporter);

$VERSION = "1.10"; # $Id: //depot/libnet/Net/Config.pm#17 $

eval { local $SIG{__DIE__}; require Net::LocalCfg };

%NetConfig = (

    nntp_hosts => [],

    snpp_hosts => [],

    pop3_hosts => [],

    smtp_hosts => [],

    ph_hosts => [],

    daytime_hosts => [],

    time_hosts => [],

    inet_domain => undef,

    ftp_firewall => undef,

    ftp_ext_passive => 0,

    ftp_int_passive => 0,

    test_hosts => 1,

    test_exist => 1,

);

#

# Try to get as much configuration info as possible from InternetConfig

#

$^O eq 'MacOS' and eval <<TRY_INTERNET_CONFIG;

use Mac::InternetConfig;

{

my %nc = (

    nntp_hosts      => [ \$InternetConfig{ kICNNTPHost() } ],

    pop3_hosts      => [ \$InternetConfig{ kICMailAccount() } =~ /\@(.*)/ ],

    smtp_hosts      => [ \$InternetConfig{ kICSMTPHost() } ],

    ftp_testhost    => \$InternetConfig{ kICFTPHost() } ? \$InternetConfig{ kICFTPHost()} : undef,

    ph_hosts        => [ \$InternetConfig{ kICPhHost() }   ],

    ftp_ext_passive => \$InternetConfig{"646F676F\xA5UsePassiveMode"} || 0,

    ftp_int_passive => \$InternetConfig{"646F676F\xA5UsePassiveMode"} || 0,

    socks_hosts     => 

    	\$InternetConfig{ kICUseSocks() }    ? [ \$InternetConfig{ kICSocksHost() }    ] : [],

    ftp_firewall    => 

    	\$InternetConfig{ kICUseFTPProxy() } ? [ \$InternetConfig{ kICFTPProxyHost() } ] : [],

);

\@NetConfig{keys %nc} = values %nc;

}

TRY_INTERNET_CONFIG

my $file = __FILE__;

my $ref;

$file =~ s/Config.pm/libnet.cfg/;

if ( -f $file ) {

    $ref = eval { local $SIG{__DIE__}; do $file };

    if (ref($ref) eq 'HASH') {

	%NetConfig = (%NetConfig, %{ $ref });

	$LIBNET_CFG = $file;

    }

}

if ($< == $> and !$CONFIGURE)  {

    my $home = eval { local $SIG{__DIE__}; (getpwuid($>))[7] } || $ENV{HOME};

    $home ||= $ENV{HOMEDRIVE} . ($ENV{HOMEPATH}||'') if defined $ENV{HOMEDRIVE};

    if (defined $home) {

	$file = $home . "/.libnetrc";

	$ref = eval { local $SIG{__DIE__}; do $file } if -f $file;

	%NetConfig = (%NetConfig, %{ $ref })

	    if ref($ref) eq 'HASH';	

    }

}

my ($k,$v);

while(($k,$v) = each %NetConfig) {

	$NetConfig{$k} = [ $v ]

		if($k =~ /_hosts$/ and $k ne "test_hosts" and defined($v) and !ref($v));

}

# Take a hostname and determine if it is inside the firewall

sub requires_firewall {

    shift; # ignore package

    my $host = shift;

    return 0 unless defined $NetConfig{'ftp_firewall'};

    $host = inet_aton($host) or return -1;

    $host = inet_ntoa($host);

    if(exists $NetConfig{'local_netmask'}) {

	my $quad = unpack("N",pack("C*",split(/\./,$host)));

	my $list = $NetConfig{'local_netmask'};

	$list = [$list] unless ref($list);

	foreach (@$list) {

	    my($net,$bits) = (m#^(\d+\.\d+\.\d+\.\d+)/(\d+)$#) or next;

	    my $mask = ~0 << (32 - $bits);

	    my $addr = unpack("N",pack("C*",split(/\./,$net)));

	    return 0 if (($addr & $mask) == ($quad & $mask));

	}

	return 1;

    }

    return 0;

}

use vars qw(*is_external);

*is_external = \&requires_firewall;

1;

__END__

=head1 NAME

Net::Config - Local configuration data for libnet

=head1 SYNOPSYS

    use Net::Config qw(%NetConfig);

=head1 DESCRIPTION

C<Net::Config> holds configuration data for the modules in the libnet

distribuion. During installation you will be asked for these values.

The configuration data is held globally in a file in the perl installation

tree, but a user may override any of these values by providing their own. This

can be done by having a C<.libnetrc> file in their home directory. This file

should return a reference to a HASH containing the keys described below.

For example

    # .libnetrc

    {

        nntp_hosts => [ "my_prefered_host" ],

	ph_hosts   => [ "my_ph_server" ],

    }

    __END__

=head1 METHODS

C<Net::Config> defines the following methods. They are methods as they are

invoked as class methods. This is because C<Net::Config> inherits from

C<Net::LocalCfg> so you can override these methods if you want.

=over 4

=item requires_firewall HOST

Attempts to determine if a given host is outside your firewall. Possible

return values are.

  -1  Cannot lookup hostname

   0  Host is inside firewall (or there is no ftp_firewall entry)

   1  Host is outside the firewall

This is done by using hostname lookup and the C<local_netmask> entry in

the configuration data.

=back

=head1 NetConfig VALUES

=over 4

=item nntp_hosts

=item snpp_hosts

=item pop3_hosts

=item smtp_hosts

=item ph_hosts

=item daytime_hosts

=item time_hosts

Each is a reference to an array of hostnames (in order of preference),

which should be used for the given protocol

=item inet_domain

Your internet domain name

=item ftp_firewall

If you have an FTP proxy firewall (B<NOT> an HTTP or SOCKS firewall)

then this value should be set to the firewall hostname. If your firewall

does not listen to port 21, then this value should be set to

C<"hostname:port"> (eg C<"hostname:99">)

=item ftp_firewall_type

There are many different ftp firewall products available. But unfortunately

there is no standard for how to traverse a firewall.  The list below shows the

sequence of commands that Net::FTP will use

  user        Username for remote host

  pass        Password for remote host

  fwuser      Username for firewall

  fwpass      Password for firewall

  remote.host The hostname of the remote ftp server

=over 4

=item 0

There is no firewall

=item 1

     USER user@remote.host

     PASS pass

=item 2

     USER fwuser

     PASS fwpass

     USER user@remote.host

     PASS pass

=item 3

     USER fwuser

     PASS fwpass

     SITE remote.site

     USER user

     PASS pass

=item 4

     USER fwuser

     PASS fwpass

     OPEN remote.site

     USER user

     PASS pass

=item 5

     USER user@fwuser@remote.site

     PASS pass@fwpass

=item 6

     USER fwuser@remote.site

     PASS fwpass

     USER user

     PASS pass

=item 7

     USER user@remote.host

     PASS pass

     AUTH fwuser

     RESP fwpass

=back

=item ftp_ext_passive

=item ftp_int_pasive

FTP servers normally work on a non-passive mode. That is when you want to

transfer data you have to tell the server the address and port to

connect to.

With some firewalls this does not work as the server cannot

connect to your machine (because you are behind a firewall) and the firewall

does not re-write the command. In this case you should set C<ftp_ext_passive>

to a I<true> value.

Some servers are configured to only work in passive mode. If you have

one of these you can force C<Net::FTP> to always transfer in passive

mode; when not going via a firewall, by setting C<ftp_int_passive> to

a I<true> value.

=item local_netmask

A reference to a list of netmask strings in the form C<"134.99.4.0/24">.

These are used by the C<requires_firewall> function to determine if a given

host is inside or outside your firewall.

=back

The following entries are used during installation & testing on the

libnet package

=over 4

=item test_hosts

If true then C<make test> may attempt to connect to hosts given in the

configuration.

=item test_exists

If true then C<Configure> will check each hostname given that it exists

=back

=for html <hr>

I<$Id: //depot/libnet/Net/Config.pm#17 $>

=head1 COPYRIGHT

Copyright (c) 2000 Graham Barr <gbarr@pobox.com>. All rights reserved.

This program is free software; you can redistribute it and/or 

modify it under the same terms as Perl itself.

=cut