sub setup_listener {
    my $self = shift;

    my $tcp = getprotobyname('tcp');
    socket( HTTPDaemon, PF_INET, SOCK_STREAM, $tcp ) or croak "socket: $!";
    setsockopt( HTTPDaemon, SOL_SOCKET, SO_REUSEADDR, pack( "l", 1 ) )
        or warn "setsockopt: $!";
    bind( HTTPDaemon,
        sockaddr_in(
            $self->port(),
            (   $self->host
                ? inet_aton( $self->host )
                : INADDR_ANY
            )
        )
        )
        or croak "bind to @{[$self->host||'*']}:@{[$self->port]}: $!";
    listen( HTTPDaemon, SOMAXCONN ) or croak "listen: $!";
}