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package Net::netent; |
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use strict; |
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|
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use 5.006_001; |
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our $VERSION = '1.00'; |
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our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); |
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BEGIN { |
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use Exporter (); |
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@EXPORT = qw(getnetbyname getnetbyaddr getnet); |
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@EXPORT_OK = qw( |
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$n_name @n_aliases |
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$n_addrtype $n_net |
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); |
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%EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); |
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} |
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use vars @EXPORT_OK; |
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|
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# Class::Struct forbids use of @ISA |
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sub import { goto &Exporter::import } |
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|
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use Class::Struct qw(struct); |
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struct 'Net::netent' => [ |
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name => '$', |
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aliases => '@', |
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addrtype => '$', |
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net => '$', |
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]; |
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|
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sub populate (@) { |
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return unless @_; |
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my $nob = new(); |
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$n_name = $nob->[0] = $_[0]; |
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@n_aliases = @{ $nob->[1] } = split ' ', $_[1]; |
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$n_addrtype = $nob->[2] = $_[2]; |
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$n_net = $nob->[3] = $_[3]; |
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return $nob; |
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} |
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|
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sub getnetbyname ($) { populate(CORE::getnetbyname(shift)) } |
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|
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sub getnetbyaddr ($;$) { |
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my ($net, $addrtype); |
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$net = shift; |
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require Socket if @_; |
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$addrtype = @_ ? shift : Socket::AF_INET(); |
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populate(CORE::getnetbyaddr($net, $addrtype)) |
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} |
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|
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sub getnet($) { |
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if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { |
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require Socket; |
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&getnetbyaddr(Socket::inet_aton(shift)); |
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} else { |
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&getnetbyname; |
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} |
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} |
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|
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1; |
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__END__ |
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|
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=head1 NAME |
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|
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Net::netent - by-name interface to Perl's built-in getnet*() functions |
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|
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=head1 SYNOPSIS |
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|
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use Net::netent qw(:FIELDS); |
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getnetbyname("loopback") or die "bad net"; |
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printf "%s is %08X\n", $n_name, $n_net; |
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|
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use Net::netent; |
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|
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$n = getnetbyname("loopback") or die "bad net"; |
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{ # there's gotta be a better way, eh? |
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@bytes = unpack("C4", pack("N", $n->net)); |
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shift @bytes while @bytes && $bytes[0] == 0; |
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} |
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printf "%s is %08X [%d.%d.%d.%d]\n", $n->name, $n->net, @bytes; |
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|
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=head1 DESCRIPTION |
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|
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This module's default exports override the core getnetbyname() and |
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getnetbyaddr() functions, replacing them with versions that return |
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"Net::netent" objects. This object has methods that return the similarly |
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named structure field name from the C's netent structure from F<netdb.h>; |
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namely name, aliases, addrtype, and net. The aliases |
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method returns an array reference, the rest scalars. |
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|
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You may also import all the structure fields directly into your namespace |
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as regular variables using the :FIELDS import tag. (Note that this still |
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overrides your core functions.) Access these fields as variables named |
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with a preceding C<n_>. Thus, C<$net_obj-E<gt>name()> corresponds to |
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$n_name if you import the fields. Array references are available as |
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regular array variables, so for example C<@{ $net_obj-E<gt>aliases() |
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}> would be simply @n_aliases. |
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|
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The getnet() function is a simple front-end that forwards a numeric |
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argument to getnetbyaddr(), and the rest |
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to getnetbyname(). |
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|
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To access this functionality without the core overrides, |
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pass the C<use> an empty import list, and then access |
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function functions with their full qualified names. |
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On the other hand, the built-ins are still available |
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via the C<CORE::> pseudo-package. |
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|
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=head1 EXAMPLES |
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|
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The getnet() functions do this in the Perl core: |
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|
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sv_setiv(sv, (I32)nent->n_net); |
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|
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The gethost() functions do this in the Perl core: |
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|
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sv_setpvn(sv, hent->h_addr, len); |
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|
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That means that the address comes back in binary for the |
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host functions, and as a regular perl integer for the net ones. |
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This seems a bug, but here's how to deal with it: |
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|
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use strict; |
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use Socket; |
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use Net::netent; |
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|
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@ARGV = ('loopback') unless @ARGV; |
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|
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my($n, $net); |
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|
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for $net ( @ARGV ) { |
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|
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unless ($n = getnetbyname($net)) { |
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warn "$0: no such net: $net\n"; |
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next; |
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} |
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|
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printf "\n%s is %s%s\n", |
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$net, |
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lc($n->name) eq lc($net) ? "" : "*really* ", |
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$n->name; |
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|
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print "\taliases are ", join(", ", @{$n->aliases}), "\n" |
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if @{$n->aliases}; |
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|
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# this is stupid; first, why is this not in binary? |
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# second, why am i going through these convolutions |
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# to make it looks right |
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{ |
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my @a = unpack("C4", pack("N", $n->net)); |
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shift @a while @a && $a[0] == 0; |
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printf "\taddr is %s [%d.%d.%d.%d]\n", $n->net, @a; |
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} |
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|
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if ($n = getnetbyaddr($n->net)) { |
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if (lc($n->name) ne lc($net)) { |
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printf "\tThat addr reverses to net %s!\n", $n->name; |
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$net = $n->name; |
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redo; |
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} |
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} |
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} |
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|
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=head1 NOTE |
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|
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While this class is currently implemented using the Class::Struct |
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module to build a struct-like class, you shouldn't rely upon this. |
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|
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=head1 AUTHOR |
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|
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Tom Christiansen |
