package App::SilverSplash::IPTables;

use strict;
use warnings;

use base 'App::SilverSplash';

use Data::Dumper qw(Dumper);

use Config::SL  ();
use URI::Escape ();

use constant DEBUG => $ENV{SL_DEBUG} || 0;

our (
    $Config,     $Iptables,     $Wan_if,  %tables_chains,
    $Lan_if,     $Perlbal_port, $Mark_op, $Lease_file,
    $Gateway_ip, $Wan_ip,       $Wan_mac,
);

BEGIN {
    $Config       = Config::SL->new;
    $Iptables     = $Config->sl_iptables || die 'oops';
    $Perlbal_port = $Config->sl_perlbal_port || die 'oops';

    # wan and lan interfaces
    $Wan_if = $Config->sl_wan_if || die 'oops';
    $Lan_if = $Config->sl_lan_if || die 'oops';

    ($Gateway_ip) = `/sbin/ifconfig $Lan_if` =~ m/inet addr:(\S+)/;
    ($Wan_ip)     = `/sbin/ifconfig $Wan_if` =~ m/inet addr:(\S+)/;
    ($Wan_mac)    = `/sbin/ifconfig $Wan_if` =~ m/HWaddr\s(\S+)/;

    $Mark_op    = $Config->sl_mark_op         || die 'oops';
    $Lease_file = $Config->sl_dhcp_lease_file || die 'oops';

    %tables_chains = (
        filter => [qw( slAUT slAUTads slNET slRTR )],
        mangle => [qw( slBLK slINC slOUT slTRU )],
        nat    => [qw( slOUT )],
    );

}

our $Blocked_mark = '0x100';
our $Trusted_mark = '0x200';
our $Paid_mark    = '0x400';
our $Ads_mark     = '0x500';

sub load_allows {
    my ( $class, $file ) = @_;

    my $fh;
    open( $fh, '<', $Config->sl_root . "/conf/$file" ) or die $!;
    my $ct = do { local $/; <$fh> };
    close($fh) or die $!;

    my @lines = split( /\n/, $ct );
    @lines = grep { $_ =~ m/\S/ }
      grep { $_ !~ /#/ }             # skip comments
      grep { defined $_ } @lines;    # skip undef

    return \@lines;
}

sub init_firewall {
    my $class = shift;

    `echo 1 > /proc/sys/net/ipv4/ip_forward`;

    # flush the existing firewall
    $class->clear_firewall();

    # create the chains
    foreach my $table ( sort keys %tables_chains ) {
        foreach my $chain ( @{ $tables_chains{$table} } ) {

            iptables("-t $table -N $chain");
        }
    }

    # walled garden exceptions
    my $hosts_allow    = $class->load_allows('cp_hosts_allow.txt');
    my $sslhosts_allow = $class->load_allows('cp_sslhosts_allow.txt');
    my $accept         = "slNET -d %s -p tcp -m tcp --dport %d -j ACCEPT";

    my $slout = "slOUT -d %s -p tcp -m tcp --dport %d -j ACCEPT";

    my $hosts_accept =
      join( "\n", map { sprintf( $accept, $_, 80 ) } @{$hosts_allow} );

    my $sslhosts_accept =
      join( "\n", map { sprintf( $accept, $_, 443 ) } @{$sslhosts_allow} );

    my $hosts_slout =
      join( "\n", map { sprintf( $slout, $_, 80 ) } @{$hosts_allow} );

    my $sslhosts_slout =
      join( "\n", map { sprintf( $slout, $_, 443 ) } @{$sslhosts_allow} );

    ##############################
    # add the filter default chains
    my $filters = <<"FILTERS";
INPUT -i $Lan_if -j slRTR

FORWARD -i $Lan_if -j slNET

slAUT --protocol tcp --source-port ! 25 -j ACCEPT

slAUTads -m state --state RELATED,ESTABLISHED -j ACCEPT
slAUTads -p tcp -m tcp --dport 22 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 80 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 110 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 143 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 443 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 465 -j ACCEPT 
slAUTads -p udp -m udp --dport 500 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 587 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 993 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 995 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 1723 -j ACCEPT 
slAUTads -p udp -m udp --dport 1701 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 3389 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 5050 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 5190 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 5222 -j ACCEPT 
slAUTads -p tcp -m tcp --dport 5223 -j ACCEPT 

slNET -m mark --mark $Blocked_mark/0x700 -j DROP
slNET -m state --state INVALID -j DROP
slNET -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
slNET -m mark --mark $Trusted_mark/0x700 -j ACCEPT
slNET -m mark --mark $Paid_mark/0x700 -j slAUT
slNET -m mark --mark $Ads_mark/0x700 -j slAUTads
slNET -p icmp -j REJECT  --reject-with icmp-port-unreachable
$hosts_accept
$sslhosts_accept
slNET -j DROP

slRTR -m mark --mark $Blocked_mark/0x700 -j DROP
slRTR -m state --state INVALID -j DROP
slRTR -m state --state RELATED,ESTABLISHED -j ACCEPT
slRTR -p tcp -m tcp ! --tcp-option 2 --tcp-flags SYN SYN -j DROP
slRTR -p tcp -m tcp --dport $Perlbal_port -j ACCEPT
slRTR -m mark --mark $Trusted_mark/0x700 -j ACCEPT
slRTR -p udp -m udp -s 10.69.0.1/16 --dport 53 -j ACCEPT
slRTR -p udp -m udp -s 10.69.0.1/16 --dport 67 -j ACCEPT
slRTR -p udp -m udp -s 10.69.0.1/16 --dport 68 -j ACCEPT
slRTR -p tcp -m tcp -s 10.69.0.1/16 --dport 20022 -j ACCEPT
slRTR -p icmp -s 10.69.0.1/16 -j ACCEPT
FILTERS

    add_rules( 'filter', $filters );

    #############################
    # default mangle chains
    my $mangles = <<"MANGLES";
PREROUTING -i $Lan_if -j slOUT
PREROUTING -i $Lan_if -j slBLK
PREROUTING -i $Lan_if -j slTRU
POSTROUTING -o $Lan_if -j slINC
MANGLES

    add_rules( 'mangle', $mangles );

    #############################
    # default nat chains
    my $nats = <<"NATS";
PREROUTING -i $Lan_if -j slOUT
POSTROUTING -o $Wan_if -j MASQUERADE

slOUT -m mark --mark $Trusted_mark/0x700 -j ACCEPT
slOUT -m mark --mark $Paid_mark/0x700 -j ACCEPT
slOUT -m mark --mark $Ads_mark/0x700 -j ACCEPT
$hosts_slout
$sslhosts_slout
slOUT -p tcp -m tcp --dport 80 -j DNAT --to-destination $Gateway_ip:$Perlbal_port
slOUT -p tcp -m tcp --dport 443 -j DNAT --to-destination $Gateway_ip:$Perlbal_port
slOUT -p udp --dport 53 -d $Gateway_ip -j ACCEPT
slOUT -p udp --dport 67 -j ACCEPT
slOUT -p udp --dport 68 -j ACCEPT
slOUT -p tcp --dport 20022 -d $Gateway_ip -j ACCEPT
slOUT -p tcp --dport $Perlbal_port -d $Gateway_ip -j ACCEPT
slOUT -j DROP
NATS

    add_rules( 'nat', $nats );

    # trusted hosts
    my $trusted_hosts = $class->load_allows('trusted_hosts.txt');
    my $out_rule =
"-t mangle -A slTRU -m mac --mac-source %s -j MARK $Mark_op $Trusted_mark";

    # TODO - arp translation
    #my $out_rule = "-t mangle -A slTRU -s %s -m mac --mac-source %s -j MARK $Mark_op $Trusted_mark";
    #my $in_rule = "-t mangle -A slINC -d %s -j ACCEPT";

    foreach my $mac ( @{$trusted_hosts} ) {

        # TODO - arp translation
        # my $ip = App::SilverSplash->ip_from_mac($mac);
        # iptables($in_rule, $ip);
        iptables( sprintf( $out_rule, $mac ) );
    }

}

sub add_rules {
    my ( $table, $rules ) = @_;

    foreach my $rule ( split( /\n/, $rules ) ) {

        chomp($rule);
        next unless $rule =~ m/\S/;    # skip blanks
        warn("$$ Adding rule $rule to table $table\n") if DEBUG;
        iptables("-t $table -A $rule");
    }
}

sub clear_firewall {
    my $class = shift;

    # clear all tables
    iptables("-t $_ -F") for keys %tables_chains;

    # clear all chains
    iptables("-t $_ -X") for keys %tables_chains;

    # reset the postrouting rule - unsure if this is needed
    # iptables("-t nat -A POSTROUTING -o $Wan_if -j MASQUERADE");
}

sub iptables {
    my $cmd = shift;
    system("sudo $Iptables $cmd") == 0
      or require Carp
      && Carp::confess "could not $Iptables '$cmd', err: $!, ret: $?\n";

    return 1;
}

sub fixup_access {
    my ( $class, $mac, $ip, $type ) = @_;

    my $uc_mac        = uc($mac);
    my $iptables_rule = `sudo $Iptables -t mangle -L -v`;

    # see if the mac address is in a rule
    my ($iptables_ip) = $iptables_rule =~
      m/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*?MAC\s+$uc_mac/i;

    my $chain = "_$type\_chain";
    if ( !$iptables_ip ) {

        warn("no rule for authed mac $mac, adding") if DEBUG;
        $class->$chain( 'A', $mac, $ip );

    }
    elsif ( $ip ne $iptables_ip ) {
        warn("iptables rules don't match, updating") if DEBUG;

        # dhcp lease probably expired, delete old rule, create new rule
        my $delete = "delete_from_$type\_chain";
        $class->$delete( $mac, $iptables_ip );
        $class->$chain( 'A', $mac, $ip );
    }
    elsif ( $ip eq $iptables_ip ) {

        # no-op
    }
    return 1;
}

sub paid_users {
    my ($class) = @_;

    return $class->users($Paid_mark);
}

sub ads_users {
    my ($class) = @_;

    return $class->users($Ads_mark);
}

sub users {
    my ( $class, $mark ) = @_;

    my @users =
      map { [ $_ =~ m/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*?MAC\s(\S+)\s/ ] }
      grep { $_ =~ m/(?:$mark)/ }
      split( '\n', `sudo $Iptables -t mangle --list` );

    return @users;
}

sub _paid_chain {
    my ( $class, $op, $mac, $ip ) = @_;
    iptables(
"-t mangle -$op slOUT -s $ip -m mac --mac-source $mac -j MARK $Mark_op $Paid_mark"
    );
    iptables("-t mangle -$op slINC -d $ip -j ACCEPT");
}

sub add_to_paid_chain {
    my ( $class, $mac, $ip ) = @_;

    my $esc_mac = URI::Escape::uri_escape($mac);

    # convert minutes to seconds
    my $stay = time() + 240 * 60;    # 4 hours
    $class->set( $mac => "$stay|paid" );

    warn("cache set $mac => $stay") if DEBUG;

    # add the mac to the paid chain
    return $class->_paid_chain( 'A', $mac, $ip );
}

sub delete_from_paid_chain {
    my ( $class, $mac, $ip ) = @_;

    return $class->_paid_chain( 'D', $mac, $ip );
}

sub check_paid_chain_for_mac {
    my ( $class, $mac ) = @_;

    return $class->_check_chain_for_mac( $Paid_mark, $mac );
}

sub _check_chain_for_mac {
    my ( $class, $mark, $mac ) = @_;

    $mac = uc($mac);

    my @lines = split( '\n', `sudo $Iptables -t mangle --list` );

    my $ip;
    foreach my $line (@lines) {

        next unless $line =~ m/^MARK/;
        last
          if ($ip) =
          $line =~ m/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*?MAC\s+$mac/i;
    }

    return unless $ip;
    return $ip;
}

sub check_ads_chain_for_mac {
    my ( $class, $mac ) = @_;

    return $class->_check_chain_for_mac( $Ads_mark, $mac );
}

sub add_to_ads_chain {
    my ( $class, $mac, $ip ) = @_;

    my $esc_mac = URI::Escape::uri_escape($mac);

    # convert minutes to seconds
    my $stay = time() + $Config->sl_visitor_limit * 60;
    $class->set( $mac => "$stay|ads" );

    warn("cache set $mac => $stay") if DEBUG;
    return $class->_ads_chain( 'A', $mac, $ip );
}

sub delete_from_ads_chain {
    my ( $class, $mac, $ip ) = @_;

    return $class->_ads_chain( 'D', $mac, $ip );
}

sub _ads_chain {
    my ( $class, $op, $mac, $ip ) = @_;

    iptables(
"-t mangle -$op slOUT -s $ip -m mac --mac-source $mac -j MARK $Mark_op $Ads_mark"
    );

    iptables("-t mangle -$op slINC -d $ip -j ACCEPT");
}

sub check_overage {
    my ( $class, $mac, $ip ) = @_;

    my $in  = `$Iptables -t mangle -n -v -x -L slINC`;
    my $out = `$Iptables -t mangle -n -v -x -L slOUT`;

    # check the megabyte limits first
    my ($bytes_in) = $in =~ m/\d+\s+(\d+).*?$ip/;
    return 1 if $bytes_in > $Config->sl_down_overage;

    my ($bytes_out) = $out =~ m/\d+\s+(\d+).*?$ip/;
    return 1 if $bytes_out > $Config->sl_up_overage;

    return;
}

1;