| 1 | package Net::netent; |
| 2 | use strict; |
| 3 | |
| 4 | use 5.006_001; |
| 5 | our $VERSION = '1.00'; |
| 6 | our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); |
| 7 | BEGIN { |
| 8 | use Exporter (); |
| 9 | @EXPORT = qw(getnetbyname getnetbyaddr getnet); |
| 10 | @EXPORT_OK = qw( |
| 11 | $n_name @n_aliases |
| 12 | $n_addrtype $n_net |
| 13 | ); |
| 14 | %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] ); |
| 15 | } |
| 16 | use vars @EXPORT_OK; |
| 17 | |
| 18 | # Class::Struct forbids use of @ISA |
| 19 | sub import { goto &Exporter::import } |
| 20 | |
| 21 | use Class::Struct qw(struct); |
| 22 | struct 'Net::netent' => [ |
| 23 | name => '$', |
| 24 | aliases => '@', |
| 25 | addrtype => '$', |
| 26 | net => '$', |
| 27 | ]; |
| 28 | |
| 29 | sub populate (@) { |
| 30 | return unless @_; |
| 31 | my $nob = new(); |
| 32 | $n_name = $nob->[0] = $_[0]; |
| 33 | @n_aliases = @{ $nob->[1] } = split ' ', $_[1]; |
| 34 | $n_addrtype = $nob->[2] = $_[2]; |
| 35 | $n_net = $nob->[3] = $_[3]; |
| 36 | return $nob; |
| 37 | } |
| 38 | |
| 39 | sub getnetbyname ($) { populate(CORE::getnetbyname(shift)) } |
| 40 | |
| 41 | sub getnetbyaddr ($;$) { |
| 42 | my ($net, $addrtype); |
| 43 | $net = shift; |
| 44 | require Socket if @_; |
| 45 | $addrtype = @_ ? shift : Socket::AF_INET(); |
| 46 | populate(CORE::getnetbyaddr($net, $addrtype)) |
| 47 | } |
| 48 | |
| 49 | sub getnet($) { |
| 50 | if ($_[0] =~ /^\d+(?:\.\d+(?:\.\d+(?:\.\d+)?)?)?$/) { |
| 51 | require Socket; |
| 52 | &getnetbyaddr(Socket::inet_aton(shift)); |
| 53 | } else { |
| 54 | &getnetbyname; |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | 1; |
| 59 | __END__ |
| 60 | |
| 61 | =head1 NAME |
| 62 | |
| 63 | Net::netent - by-name interface to Perl's built-in getnet*() functions |
| 64 | |
| 65 | =head1 SYNOPSIS |
| 66 | |
| 67 | use Net::netent qw(:FIELDS); |
| 68 | getnetbyname("loopback") or die "bad net"; |
| 69 | printf "%s is %08X\n", $n_name, $n_net; |
| 70 | |
| 71 | use Net::netent; |
| 72 | |
| 73 | $n = getnetbyname("loopback") or die "bad net"; |
| 74 | { # there's gotta be a better way, eh? |
| 75 | @bytes = unpack("C4", pack("N", $n->net)); |
| 76 | shift @bytes while @bytes && $bytes[0] == 0; |
| 77 | } |
| 78 | printf "%s is %08X [%d.%d.%d.%d]\n", $n->name, $n->net, @bytes; |
| 79 | |
| 80 | =head1 DESCRIPTION |
| 81 | |
| 82 | This module's default exports override the core getnetbyname() and |
| 83 | getnetbyaddr() functions, replacing them with versions that return |
| 84 | "Net::netent" objects. This object has methods that return the similarly |
| 85 | named structure field name from the C's netent structure from F<netdb.h>; |
| 86 | namely name, aliases, addrtype, and net. The aliases |
| 87 | method returns an array reference, the rest scalars. |
| 88 | |
| 89 | You may also import all the structure fields directly into your namespace |
| 90 | as regular variables using the :FIELDS import tag. (Note that this still |
| 91 | overrides your core functions.) Access these fields as variables named |
| 92 | with a preceding C<n_>. Thus, C<$net_obj-E<gt>name()> corresponds to |
| 93 | $n_name if you import the fields. Array references are available as |
| 94 | regular array variables, so for example C<@{ $net_obj-E<gt>aliases() |
| 95 | }> would be simply @n_aliases. |
| 96 | |
| 97 | The getnet() function is a simple front-end that forwards a numeric |
| 98 | argument to getnetbyaddr(), and the rest |
| 99 | to getnetbyname(). |
| 100 | |
| 101 | To access this functionality without the core overrides, |
| 102 | pass the C<use> an empty import list, and then access |
| 103 | function functions with their full qualified names. |
| 104 | On the other hand, the built-ins are still available |
| 105 | via the C<CORE::> pseudo-package. |
| 106 | |
| 107 | =head1 EXAMPLES |
| 108 | |
| 109 | The getnet() functions do this in the Perl core: |
| 110 | |
| 111 | sv_setiv(sv, (I32)nent->n_net); |
| 112 | |
| 113 | The gethost() functions do this in the Perl core: |
| 114 | |
| 115 | sv_setpvn(sv, hent->h_addr, len); |
| 116 | |
| 117 | That means that the address comes back in binary for the |
| 118 | host functions, and as a regular perl integer for the net ones. |
| 119 | This seems a bug, but here's how to deal with it: |
| 120 | |
| 121 | use strict; |
| 122 | use Socket; |
| 123 | use Net::netent; |
| 124 | |
| 125 | @ARGV = ('loopback') unless @ARGV; |
| 126 | |
| 127 | my($n, $net); |
| 128 | |
| 129 | for $net ( @ARGV ) { |
| 130 | |
| 131 | unless ($n = getnetbyname($net)) { |
| 132 | warn "$0: no such net: $net\n"; |
| 133 | next; |
| 134 | } |
| 135 | |
| 136 | printf "\n%s is %s%s\n", |
| 137 | $net, |
| 138 | lc($n->name) eq lc($net) ? "" : "*really* ", |
| 139 | $n->name; |
| 140 | |
| 141 | print "\taliases are ", join(", ", @{$n->aliases}), "\n" |
| 142 | if @{$n->aliases}; |
| 143 | |
| 144 | # this is stupid; first, why is this not in binary? |
| 145 | # second, why am i going through these convolutions |
| 146 | # to make it looks right |
| 147 | { |
| 148 | my @a = unpack("C4", pack("N", $n->net)); |
| 149 | shift @a while @a && $a[0] == 0; |
| 150 | printf "\taddr is %s [%d.%d.%d.%d]\n", $n->net, @a; |
| 151 | } |
| 152 | |
| 153 | if ($n = getnetbyaddr($n->net)) { |
| 154 | if (lc($n->name) ne lc($net)) { |
| 155 | printf "\tThat addr reverses to net %s!\n", $n->name; |
| 156 | $net = $n->name; |
| 157 | redo; |
| 158 | } |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | =head1 NOTE |
| 163 | |
| 164 | While this class is currently implemented using the Class::Struct |
| 165 | module to build a struct-like class, you shouldn't rely upon this. |
| 166 | |
| 167 | =head1 AUTHOR |
| 168 | |
| 169 | Tom Christiansen |