#!/usr/bin/perl
package Karma;

use strict;
use warnings;

BEGIN { @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File) }
use AnyDBM_File;
use Data::Dumper;
use Fcntl qw(:DEFAULT :flock LOCK_EX LOCK_NB);
use Net::IP qw(:PROC);
use POSIX qw(strftime);

my $self = bless( { args => { db_dir => 'config' }, }, 'Karma' );
my $command = $ARGV[0];

if ( ! $command ) {
    $self->usage();
}
elsif ( $command eq 'capture' ) {
    $self->capture( $ARGV[1] );
}
elsif ( $command eq 'release' ) {
    $self->capture( $ARGV[1] );
}
elsif ( $command eq 'prune' ) {
    $self->prune_db( $ARGV[1] || 7 );
}
elsif ( $command eq 'list' ) {
    $self->main();
};

exit(0);

sub usage {
    print <<EO_HELP
 karma_tool [ list search prune capture release ]

list takes no arguments.

search [ naughty nice both ]
  and returns a list of matching IPs

capture [ IP ]
  sends an IP to the penalty box

release [ IP ]
  remove an IP from the penalty box

prune takes no arguments.
  prunes database of entries older than 7 days

EO_HELP
;
};

sub capture {
    my $self = shift;
    my $ip = shift or return;
    is_ip( $ip ) or do {
        warn "not an IP: $ip\n";
        return;
    };

    my $db   = $self->get_db_location();
    my $lock = $self->get_db_lock( $db ) or return;
    my $tied = $self->get_db_tie( $db, $lock ) or return;
    my $key  = $self->get_db_key( $ip );

    $tied->{$key} = join(':', time, 1, 0, 1);
    return $self->cleanup_and_return( $tied, $lock );
};

sub release {
    my $self = shift;
    my $ip = shift or return;
    is_ip( $ip ) or do {
        warn "not an IP: $ip\n";
        return;
    };

    my $db   = $self->get_db_location();
    my $lock = $self->get_db_lock( $db ) or return;
    my $tied = $self->get_db_tie( $db, $lock ) or return;
    my $key  = $self->get_db_key( $ip );

    $tied->{$key} = join(':', 0, 1, 0, 1);
    return $self->cleanup_and_return( $tied, $lock );
};

sub main {
    my $self = shift;

    my $db   = $self->get_db_location();
    my $lock = $self->get_db_lock( $db ) or return;
    my $tied = $self->get_db_tie( $db, $lock ) or return;
    my %totals;

    print "      IP Address                 Penalty        Naughty  Nice  Connects  Hostname\n";
    foreach my $r ( sort keys %$tied ) {
        my $ip = ip_bintoip( ip_inttobin( $r, 4 ), 4);
        my ($penalty_start_ts, $naughty, $nice, $connects) = split /:/, $tied->{$r};
        $naughty ||= '';
        $nice    ||= '';
        $connects ||= '';
        my $time_human = '';
        if ( $command eq 'search' ) {
            my $search = $ARGV[1];
            if ( $search eq 'nice' ) {
                next if ! $nice;
            }
            elsif ( $search eq 'naughty' ) {
                next if ! $naughty;
            }
            elsif ( $search eq 'both' ) {
                next if ! $naughty || ! $nice;
            }
            elsif ( is_ip() && $search ne $ip ) {
                next;
            }
        };
        if ( $penalty_start_ts ) {
            $time_human = strftime "%a %b %e %H:%M", localtime $penalty_start_ts;
        };
        my $hostname = '';
        if ( $naughty && $nice ) {
            $hostname = `dig +short -x $ip`; chomp $hostname;
        };
        printf(" %-18s  %24s    %3s     %3s     %3s    %30s\n", $ip, $time_human, $naughty, $nice, $connects, $hostname);
        $totals{naughty}  += $naughty  if $naughty;
        $totals{nice}     += $nice     if $nice;
        $totals{connects} += $connects if $connects;
    };
    print Dumper(\%totals);
}

sub is_ip {
    my $ip = shift || $ARGV[0];
    return 1 if $ip =~ /^(\d{1,3}\.){3}\d{1,3}$/;
    return;
};

sub cleanup_and_return {
    my ($self, $tied, $lock ) = @_;
    untie $tied;
    close $lock;
};

sub get_db_key {
    my $self = shift;
    my $nip = Net::IP->new( shift );
    return $nip->intip;   # convert IP to an int
};

sub get_db_tie {
    my ( $self, $db, $lock ) = @_;

    tie( my %db, 'AnyDBM_File', $db, O_CREAT|O_RDWR, 0600) or do {
        warn "tie to database $db failed: $!";
        close $lock;
        return;
    };
    return \%db;
};

sub get_db_location {
    my $self = shift;

    # Setup database location
    my @candidate_dirs = ( $self->{args}{db_dir},
        "/var/lib/qpsmtpd/karma", "./var/db", "./config", '.' );

    my $dbdir;
    for my $d ( @candidate_dirs ) {
        next if ! $d || ! -d $d;   # impossible
        $dbdir = $d;
        last;   # first match wins
    }
    my $db = "$dbdir/karma.dbm";
    print "using karma db at $db\n";
    return $db;
};

sub get_db_lock {
    my ($self, $db) = @_;

    return $self->get_db_lock_nfs($db) if $self->{_args}{nfslock};

    # Check denysoft db
    open( my $lock, ">$db.lock" ) or do {
        warn "opening lockfile failed: $!";
        return;
    };

    flock( $lock, LOCK_EX ) or do {
        warn "flock of lockfile failed: $!";
        close $lock;
        return;
    };

    return $lock;
}

sub get_db_lock_nfs {
    my ($self, $db) = @_;

    require File::NFSLock;

    ### set up a lock - lasts until object looses scope
    my $nfslock = new File::NFSLock {
        file      => "$db.lock",
        lock_type => LOCK_EX|LOCK_NB,
        blocking_timeout   => 10,      # 10 sec
        stale_lock_timeout => 30 * 60, # 30 min
    } or do {
        warn "nfs lockfile failed: $!";
        return;
    };

    open( my $lock, "+<$db.lock") or do {
        warn "opening nfs lockfile failed: $!";
        return;
    };

    return $lock;
};

sub prune_db {
    my $self = shift;
    my $prune_days = shift;

    my $db   = $self->get_db_location();
    my $lock = $self->get_db_lock( $db ) or return;
    my $tied = $self->get_db_tie( $db, $lock ) or return;
    my $count = keys %$tied;

    my $pruned = 0;
    foreach my $key ( keys %$tied ) {
        my ($ts, $naughty, $nice, $connects) = split /:/, $tied->{$key};
        my $days_old = ( time - $ts ) / 86400;
        next if $days_old < $prune_days;
        delete $tied->{$key};
        $pruned++;
    };
    untie $tied;
    close $lock;
    warn "pruned $pruned of $count DB entries";
    return $self->cleanup_and_return( $tied, $lock );
};