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resolved: cache - don't cache NXDOMAIN by TYPE

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An NXDOMAIN entry means there are no RRs of any type for a name,
so only cache by CLASS + NAME, rather than CLASS + NAME + TYPE.
This commit is contained in:
Tom Gundersen 2015-12-03 19:53:35 +01:00
parent 5d27351f85
commit 71e136699c
1 changed files with 17 additions and 1 deletions
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18
src/resolve/resolved-dns-cache.c
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@ -364,6 +364,8 @@ static int dns_cache_put_negative(
if (key->class == DNS_CLASS_ANY)
return 0;
if (key->type == DNS_TYPE_ANY)
/* This is particularly important to filter out as we use this as a
* pseudo-type for NXDOMAIN entries */
return 0;
if (soa_ttl <= 0) {
r = dns_resource_key_to_string(key, &key_str);
@ -389,13 +391,21 @@ static int dns_cache_put_negative(
return -ENOMEM;
i->type = rcode == DNS_RCODE_SUCCESS ? DNS_CACHE_NODATA : DNS_CACHE_NXDOMAIN;
i->key = dns_resource_key_ref(key);
i->until = timestamp + MIN(soa_ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC);
i->prioq_idx = PRIOQ_IDX_NULL;
i->owner_family = owner_family;
i->owner_address = *owner_address;
i->authenticated = authenticated;
if (i->type == DNS_CACHE_NXDOMAIN) {
/* NXDOMAIN entries should apply equally to all types, so we use ANY as
* a pseudo type for this purpose here. */
i->key = dns_resource_key_new(key->class, DNS_TYPE_ANY, DNS_RESOURCE_KEY_NAME(key));
if (!i->key)
return -ENOMEM;
} else
i->key = dns_resource_key_ref(key);
r = dns_cache_link_item(c, i);
if (r < 0)
return r;
@ -534,6 +544,12 @@ static DnsCacheItem *dns_cache_get_by_key_follow_cname_dname_nsec(DnsCache *c, D
n = DNS_RESOURCE_KEY_NAME(k);
/* Check if we have an NXDOMAIN cache item for the name, notice that we use
* the pseudo-type ANY for NXDOMAIN cache items. */
i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_ANY, n));
if (i && i->type == DNS_CACHE_NXDOMAIN)
return i;
/* Check if we have an NSEC record instead for the name. */
i = hashmap_get(c->by_key, &DNS_RESOURCE_KEY_CONST(k->class, DNS_TYPE_NSEC, n));
if (i)