Initial Commit

database/perl/lib/Net/netent.pm

@@ -0,0 +1,173 @@
+package Net::netent;
+use strict;
+
+use 5.006_001;
+our $VERSION = '1.01';
+our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS);
+our (
+    $n_name, @n_aliases,
+    $n_addrtype, $n_net
+);
+ 
+BEGIN { 
+    use Exporter   ();
+    @EXPORT      = qw(getnetbyname getnetbyaddr getnet);
+    @EXPORT_OK   = qw(
+			$n_name	    	@n_aliases
+			$n_addrtype 	$n_net
+		   );
+    %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] );
+}
+
+# Class::Struct forbids use of @ISA
+sub import { goto &Exporter::import }
+
+use Class::Struct qw(struct);
+struct 'Net::netent' => [
+   name		=> '$',
+   aliases	=> '@',
+   addrtype	=> '$',
+   net		=> '$',
+];
+
+sub populate (@) {
+    return unless @_;
+    my $nob = new();
+    $n_name 	 =    $nob->[0]     	     = $_[0];
+    @n_aliases	 = @{ $nob->[1] } = split ' ', $_[1];
+    $n_addrtype  =    $nob->[2] 	     = $_[2];
+    $n_net	 =    $nob->[3] 	     = $_[3];
+    return $nob;
+} 
+
+sub getnetbyname ($)  { populate(CORE::getnetbyname(shift)) } 
+
+sub getnetbyaddr ($;$) { 
+    my ($net, $addrtype);
+    $net = shift;
+    require Socket if @_;
+    $addrtype = @_ ? shift : Socket::AF_INET();
+    populate(CORE::getnetbyaddr($net, $addrtype)) 
+} 
+
+sub getnet($) {
+    if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) {
+	require Socket;
+	&getnetbyaddr(Socket::inet_aton(shift));
+    } else {
+	&getnetbyname;
+    } 
+} 
+
+1;
+__END__
+
+=head1 NAME
+
+Net::netent - by-name interface to Perl's built-in getnet*() functions
+
+=head1 SYNOPSIS
+
+ use Net::netent qw(:FIELDS);
+ getnetbyname("loopback") 		or die "bad net";
+ printf "%s is %08X\n", $n_name, $n_net;
+
+ use Net::netent;
+
+ $n = getnetbyname("loopback") 		or die "bad net";
+ { # there's gotta be a better way, eh?
+     @bytes = unpack("C4", pack("N", $n->net));
+     shift @bytes while @bytes && $bytes[0] == 0;
+ }
+ printf "%s is %08X [%d.%d.%d.%d]\n", $n->name, $n->net, @bytes;
+
+=head1 DESCRIPTION
+
+This module's default exports override the core getnetbyname() and
+getnetbyaddr() functions, replacing them with versions that return
+"Net::netent" objects.  This object has methods that return the similarly
+named structure field name from the C's netent structure from F<netdb.h>;
+namely name, aliases, addrtype, and net.  The aliases 
+method returns an array reference, the rest scalars.  
+
+You may also import all the structure fields directly into your namespace
+as regular variables using the :FIELDS import tag.  (Note that this still
+overrides your core functions.)  Access these fields as variables named
+with a preceding C<n_>.  Thus, C<$net_obj-E<gt>name()> corresponds to
+$n_name if you import the fields.  Array references are available as
+regular array variables, so for example C<@{ $net_obj-E<gt>aliases()
+}> would be simply @n_aliases.
+
+The getnet() function is a simple front-end that forwards a numeric
+argument to getnetbyaddr(), and the rest
+to getnetbyname().
+
+To access this functionality without the core overrides,
+pass the C<use> an empty import list, and then access
+function functions with their full qualified names.
+On the other hand, the built-ins are still available
+via the C<CORE::> pseudo-package.
+
+=head1 EXAMPLES
+
+The getnet() functions do this in the Perl core:
+
+    sv_setiv(sv, (I32)nent->n_net);
+
+The gethost() functions do this in the Perl core:
+
+    sv_setpvn(sv, hent->h_addr, len);
+
+That means that the address comes back in binary for the
+host functions, and as a regular perl integer for the net ones.
+This seems a bug, but here's how to deal with it:
+
+ use strict;
+ use Socket;
+ use Net::netent;
+
+ @ARGV = ('loopback') unless @ARGV;
+
+ my($n, $net);
+
+ for $net ( @ARGV ) {
+
+     unless ($n = getnetbyname($net)) {
+ 	warn "$0: no such net: $net\n";
+ 	next;
+     }
+
+     printf "\n%s is %s%s\n", 
+ 	    $net, 
+ 	    lc($n->name) eq lc($net) ? "" : "*really* ",
+ 	    $n->name;
+
+     print "\taliases are ", join(", ", @{$n->aliases}), "\n"
+ 		if @{$n->aliases};     
+
+     # this is stupid; first, why is this not in binary?
+     # second, why am i going through these convolutions
+     # to make it looks right
+     {
+ 	my @a = unpack("C4", pack("N", $n->net));
+ 	shift @a while @a && $a[0] == 0;
+ 	printf "\taddr is %s [%d.%d.%d.%d]\n", $n->net, @a;
+     }
+
+     if ($n = getnetbyaddr($n->net)) {
+ 	if (lc($n->name) ne lc($net)) {
+ 	    printf "\tThat addr reverses to net %s!\n", $n->name;
+ 	    $net = $n->name;
+ 	    redo;
+ 	} 
+     }
+ }
+
+=head1 NOTE
+
+While this class is currently implemented using the Class::Struct
+module to build a struct-like class, you shouldn't rely upon this.
+
+=head1 AUTHOR
+
+Tom Christiansen