--------------------------8<------------------------------code : MyMilter.pl----
#!/usr/bin/perl

use Sendmail::Milter;
use Socket;
use MIME::Base64;

sub connect_callback {
    my ($ctx, $hostname, $sockaddr_in) = @_;

    print "[connect] hostname: '$hostname'\n";

    return SMFIS_CONTINUE;
}

sub helo_callback {
    my ($ctx, $helohost) = @_;

    print "    [helo] helohost: '$helohost'\n";

    return SMFIS_CONTINUE;
}

sub envfrom_callback {
    my ($ctx, $from, @args) = @_;

    print "    [envfrom] args: '$from','" . join("','", @args) . "'\n";

    # 익명 송신자 제거
    if ($from !~ /.*\@.*/) {
        print("    ! from nobody: $from\n");
        return SMFIS_REJECT;
    }

    return SMFIS_CONTINUE;
}

sub envrcpt_callback {
    my ($ctx, $rcpt, @args) = @_;

    print "    [envrcpt] args: '$rcpt','" . join("','", @args) . "'\n";

    # 익명 수신자 제거
    if ($rcpt !~ /.*\@.*/) {
        print("    ! rcpt nobody: $rcpt\n");
        return SMFIS_REJECT;
    }

    return SMFIS_CONTINUE;
}

sub check_subject {
    my ($subject) = @_;

    # 광고 및 홍보 제거
    if ($subject =~ /[[(< ({].*(광.*고|홍.*보).*[])>) }]/) {
        print("    ! ad: $subject\n");
        return "bad";
    }
    # 포르노 제거
    if ($subject =~ /.*(포르노|porno).*/) {
        print("    ! porno: $subject\n");
        return "bad";
    }
    return "good";
}

sub header_callback {
    my ($ctx, $headerf, $headerv) = @_;

    # Subject: 헤더인 경우.
    if ($headerf eq "Subject") {
        $chk = &check_subject($headerv);
        if ($chk eq "bad") {
            return SMFIS_REJECT;
        }

        # base64 디코딩을 수행
        @decoded = split(/[\?+\n+ +\t+]/, $headerv);
        $headerv = "";
        foreach (@decoded) {
            $headerv .= decode_base64($_);
        }

        $chk = &check_subject($headerv);
        if ($chk eq "bad") {
            return SMFIS_REJECT;
        }
    }

    return SMFIS_CONTINUE;
}

sub eoh_callback {
    my ($ctx) = @_;

    return SMFIS_CONTINUE;
}

sub check_body {
    my ($body) = @_;

    # 본문 광고 체크 : 정보통신부
    if ($body =~ /정보통신부 *권고 *사항에 *의거/) {
        print("    ! ad: 정보통신부 권고 사항에 의거한 내용\n");
        return "bad";
    }
    return "good";
}

sub body_callback {
    my ($ctx, $body_chunk, $len) = @_;

    print("    [body] length: $len\n");

    # 적당하지 않은 첨부파일이 있을시 거부 *.src, *.pif, *.bat, *.com
    @decoded = split(/[\r+\n+]/, $body_chunk);
    foreach (@decoded) {
        if ($_ =~ /name=\"?.*\.(scr|pif|bat|com)\"?/) {
            print("    ! virus?: $_\n");
            return SMFIS_REJECT;
        }
    }

    $chk = &check_body($body_chunk);
    if ($chk eq "bad") {
        return SMFIS_REJECT;
    }

    # base64 디코딩을 수행
    @decoded = split(/[\?+\r+\n+ +\t+]/, $body_chunk);
    $body_chunk = "";
    foreach (@decoded) {
        $body_chunk .= decode_base64($_);
    }

    $chk = &check_body($body_chunk);
    if ($chk eq "bad") {
        return SMFIS_REJECT;
    }

    return SMFIS_CONTINUE;
}

sub eom_callback {
    my ($ctx) = @_;

    $ctx->addheader("X-MyMilter", "Spam,Virus Chk 1.01beta [Perl version]");

    return SMFIS_CONTINUE;
}

sub abort_callback {
    my ($ctx) = @_;

    return SMFIS_CONTINUE;
}

sub close_callback {
    my ($ctx) = @_;

    return SMFIS_CONTINUE;
}

############################################
# 이하의 코드는 밀터 기본 코드로 수정 불가 #
############################################

my %my_callbacks = (
    'connect' => \&connect_callback,
    'helo'    => \&helo_callback,
    'envfrom' => \&envfrom_callback,
    'envrcpt' => \&envrcpt_callback,
    'header'  => \&header_callback,
    'eoh'     => \&eoh_callback,
    'body'    => \&body_callback,
    'eom'     => \&eom_callback,
    'abort'   => \&abort_callback,
    'close'   => \&close_callback,
);

BEGIN:
{
    if (scalar(@ARGV) < 2) {
        print "Usage: perl $0  \n";
        exit;
    }

    my $conn = Sendmail::Milter::auto_getconn($ARGV[0], $ARGV[1]);

    print "Found connection info for '$ARGV[0]': $conn\n";

    if ($conn =~ /^local:(.+)$/) {
        my $unix_socket = $1;

        if (-e $unix_socket) {
            print "Attempting to UNIX socket '$conn' ...";

            if (unlink($unix_socket) == 0) {
                print "failed.\n";
                exit;
            }
            print "successful.\n";
        }
    }

    if (!Sendmail::Milter::auto_setconn($ARGV[0], $ARGV[1])) {
        print "Failed to detect connection information.\n";
        exit;
    }

    if (!Sendmail::Milter::register($ARGV[0], \%my_callbacks, SMFI_CURR_ACTS)) {
        print "Failed to register callbacks for $ARGV[0].\n";
        exit;
    }

    print("Starting Sendmail::Milter $Sendmail::Milter::VERSION engine.\n");

    if (Sendmail::Milter::main()) {
        print "Successful exit from the Sendmail::Milter engine.\n";
    }
    else {
        print "Unsuccessful exit from the Sendmail::Milter engine.\n";
    }
}
--------------------------8<------------------------------code : MyMilter.pl----