=head1 NAME

SPF - plugin to implement Sender Permitted From

=head1 SYNOPSIS

  # in config/plugins
  sender_permitted_from

Or if you wish to issue 5xx on SPF fail:

  sender_permitted_from spf_deny 1

=cut

use Mail::SPF::Query;

sub register {
  my ($self, $qp, @args) = @_;
  %{$self->{_args}} = @args;
  $self->register_hook("mail", "mail_handler");
  $self->register_hook("rcpt", "rcpt_handler");
  $self->register_hook("data_post", "data_handler");
}

sub mail_handler {
  my ($self, $transaction, $sender) = @_;

  return (DECLINED) unless ($sender->format ne "<>"
                            and $sender->host && $sender->user);

  my $host = lc $sender->host;
  my $from = $sender->user . '@' . $host;

  my $ip = $self->qp->connection->remote_ip;
  my $query = Mail::SPF::Query->new(ip => $ip, sender => $from)
    || die "Couldn't construct Mail::SPF::Query object";
  $transaction->notes('spfquery', $query);
               
  return (DECLINED);
}

sub rcpt_handler {
  my ($self, $transaction, $rcpt) = @_;
  my $query = $transaction->notes('spfquery');
  my ($result, $comment) = $query->result();
  
  $self->qp->connection->notes('spf_result', $result);
  $self->qp->connection->notes('spf_comment', $comment);

  if ($result eq "fail" and $self->{_args}{spf_deny}) {
    return (DENY, "SPF forgery ($comment)");
  }
   
  return (DECLINED);
}

sub data_handler {
    my ($self, $transaction) = @_;
    
    my $spf = $self->qp->connection->notes('spf_result');

    my $host = $self->qp->connection->remote_host;
    my $ip = $self->qp->connection->remote_ip;
    my $sender = $transaction->sender;

    my $details = '';
    if ($spf eq 'fail') {
        $details = "fail (client $host[$ip] is not a designated mailer for domain of sender $sender)";
    }
    elsif ($spf eq 'softfail') {
        $details = "error (temporary failure while resolving designated mailer status for domain of sender $sender)";
    }
    elsif ($spf eq 'pass') {
        $details = "pass (client $host[$ip] is designated mailer for domain of sender $sender)";
    }
    else {
        $details = "unknown (domain of sender $sender does not designate mailers)";
    }
    $transaction->header->add('Received-SPF' => $details);

    return DECLINED;
}