I think you'll have to add code to your main loop to handle the packet when it comes in, and pass it off to the subroutine that can deal with it. Here's some pseudocode:
MainLoop: while ($packet = getpacket())
{
if ($packet == RESPONSE_PACKET)
{
deal_with_response();
}
else
{
dispatch_packet();
}
}
sub dispatch_packet
{
my $packet = shift;
if ($packet == NORMAL_PACKET)
{
ordinary_handler();
}
elsif ($packet == SPECIAL_PACKET)
{
special_handler();
}
}
sub ordinary_handler
{
whatever();
}
sub special_handler
{
ask_for_info();
# save the state so that we can deal
# with the response later
save_state();
}
sub deal_with_response
{
# get the saved state and deal with the response
load_state();
talk_to_the_hand();
}
__END__
The implementation details are left as an exercise for the reader.