V_sptree_ifnet
TAILQ_INSERT_TAIL(&V_sptree_ifnet[spp[i]->spidx.dir],
TAILQ_REMOVE(&V_sptree_ifnet[spp[i]->spidx.dir],
TAILQ_FOREACH(sp, &V_sptree_ifnet[dir], chain)
TAILQ_FOREACH(sp, &V_sptree_ifnet[dir], chain) {
TAILQ_INIT(&V_sptree_ifnet[i]);
TAILQ_CONCAT(&drainq, &V_sptree_ifnet[i], chain);