/usr/share/qpsmtpd/plugins/loop is in qpsmtpd 0.94-2.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | #!perl -w
=head1 NAME
loop - Detect mail loops
=head1 DESCRIPTION
This plugin detects loops by counting "Received" and "Delivered-To"
header lines. It's a kluge but it duplicates what qmail-smtpd does,
and it does at least prevent messages from looping forever.
=head1 CONFIGURATION
Takes one optional parameter, the maximum number of "hops" ("Received"
and lines plus "Delivered-To" lines) allowed. The default is 100, the
same as in qmail-smtpd.
=head1 AUTHOR
Written by Keith C. Ivey
=head1 LICENSE
Released to the public domain, 17 June 2005.
=cut
use Qpsmtpd::DSN;
sub init {
my ($self, $qp, @args) = @_;
$self->{_max_hops} = $args[0] || 100;
if ($self->{_max_hops} !~ /^\d+$/) {
$self->log(LOGWARN, "Invalid max_hops value -- using default");
$self->{_max_hops} = 100;
}
$self->log(LOGWARN, "Ignoring additional arguments") if @args > 1;
}
sub hook_data_post {
my ($self, $transaction) = @_;
my $hops = 0;
$hops++
for $transaction->header->get('Received'),
$transaction->header->get('Delivered-To');
if ($hops >= $self->{_max_hops}) {
# default of too_many_hops is DENY, see comment in POD of Qpsmtpd::DSN
return Qpsmtpd::DSN->too_many_hops();
}
return DECLINED;
}
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