IGMP_TIMER_SCALE
ih->code = mrt / (HZ / IGMP_TIMER_SCALE);
ihv3->code = igmpv3_mrc(mrt / (HZ / IGMP_TIMER_SCALE));
max_delay = ih->code * (HZ / IGMP_TIMER_SCALE);
igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE) : 1;
max_delay = igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE);
max_delay = igmpv3_mrt(ih3) * (HZ / IGMP_TIMER_SCALE);
max_delay = ih->code*(HZ/IGMP_TIMER_SCALE);