/**
* Remove NSEC records between start and end points.
* By walking the tree, the tree is sorted canonically.
* @param neg: negative cache.
* @param zone: the zone
* @param el: element to start walking at.
* @param nsec: the nsec record with the end point
*/
static void wipeout(struct val_neg_cache* neg, struct val_neg_zone* zone,
struct val_neg_data* el, struct ub_packed_rrset_key* nsec)
{
struct packed_rrset_data* d = (struct packed_rrset_data*)nsec->
entry.data;
uint8_t* end;
size_t end_len;
int end_labs, m;
rbnode_t* walk, *next;
struct val_neg_data* cur;
uint8_t buf[257];
/* get endpoint */
if(!d || d->count == 0 || d->rr_len[0] < 2+1)
return;
if(ntohs(nsec->rk.type) == LDNS_RR_TYPE_NSEC) {
end = d->rr_data[0]+2;
end_len = dname_valid(end, d->rr_len[0]-2);
end_labs = dname_count_labels(end);
} else {
/* NSEC3 */
if(!nsec3_get_nextowner_b32(nsec, 0, buf, sizeof(buf)))
return;
end = buf;
end_labs = dname_count_size_labels(end, &end_len);
}
/* sanity check, both owner and end must be below the zone apex */
if(!dname_subdomain_c(el->name, zone->name) ||
!dname_subdomain_c(end, zone->name))
return;
/* detect end of zone NSEC ; wipe until the end of zone */
if(query_dname_compare(end, zone->name) == 0) {
end = NULL;
}
walk = rbtree_next(&el->node);
while(walk && walk != RBTREE_NULL) {
cur = (struct val_neg_data*)walk;
/* sanity check: must be larger than start */
if(dname_canon_lab_cmp(cur->name, cur->labs,
el->name, el->labs, &m) <= 0) {
/* r == 0 skip original record. */
/* r < 0 too small! */
walk = rbtree_next(walk);
continue;
}
/* stop at endpoint, also data at empty nonterminals must be
* removed (no NSECs there) so everything between
* start and end */
if(end && dname_canon_lab_cmp(cur->name, cur->labs,
end, end_labs, &m) >= 0) {
break;
}
/* this element has to be deleted, but we cannot do it
* now, because we are walking the tree still ... */
/* get the next element: */
next = rbtree_next(walk);
/* now delete the original element, this may trigger
* rbtree rebalances, but really, the next element is
* the one we need.
* But it may trigger delete of other data and the
* entire zone. However, if that happens, this is done
* by deleting the *parents* of the element for deletion,
* and maybe also the entire zone if it is empty.
* But parents are smaller in canonical compare, thus,
* if a larger element exists, then it is not a parent,
* it cannot get deleted, the zone cannot get empty.
* If the next==NULL, then zone can be empty. */
if(cur->in_use)
neg_delete_data(neg, cur);
walk = next;
}
}
/** remove a random item */
static void remove_item(struct val_neg_cache* neg)
{
int n, i;
struct val_neg_data* d;
rbnode_t* walk;
struct val_neg_zone* z;
lock_basic_lock(&neg->lock);
if(neg->tree.count == 0) {
lock_basic_unlock(&neg->lock);
return; /* nothing to delete */
}
/* pick a random zone */
walk = rbtree_first(&neg->tree); /* first highest parent, big count */
z = (struct val_neg_zone*)walk;
n = random() % (int)(z->count);
if(negverbose)
printf("neg stress delete zone %d\n", n);
i=0;
walk = rbtree_first(&neg->tree);
z = (struct val_neg_zone*)walk;
while(i!=n+1 && walk && walk != RBTREE_NULL && !z->in_use) {
walk = rbtree_next(walk);
z = (struct val_neg_zone*)walk;
if(z->in_use)
i++;
}
if(!walk || walk == RBTREE_NULL) {
lock_basic_unlock(&neg->lock);
return;
}
if(!z->in_use) {
lock_basic_unlock(&neg->lock);
return;
}
if(negverbose)
log_nametypeclass(0, "delete zone", z->name, 0, 0);
/* pick a random nsec item. - that is in use */
walk = rbtree_first(&z->tree); /* first is highest parent */
d = (struct val_neg_data*)walk;
n = random() % (int)(d->count);
if(negverbose)
printf("neg stress delete item %d\n", n);
i=0;
walk = rbtree_first(&z->tree);
d = (struct val_neg_data*)walk;
while(i!=n+1 && walk && walk != RBTREE_NULL && !d->in_use) {
walk = rbtree_next(walk);
d = (struct val_neg_data*)walk;
if(d->in_use)
i++;
}
if(!walk || walk == RBTREE_NULL) {
lock_basic_unlock(&neg->lock);
return;
}
if(d->in_use) {
if(negverbose)
log_nametypeclass(0, "neg delete item:", d->name, 0, 0);
neg_delete_data(neg, d);
}
lock_basic_unlock(&neg->lock);
}
