unsigned prioq_idx;
int owner_family;
union in_addr_union owner_address;
LIST_FIELDS(DnsCacheItem, by_key);
};
static void dns_cache_item_free(DnsCacheItem *i) {
if (!i)
return;
dns_resource_record_unref(i->rr);
dns_resource_key_unref(i->key);
free(i);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(DnsCacheItem*, dns_cache_item_free);
static void dns_cache_item_remove_and_free(DnsCache *c, DnsCacheItem *i) {
DnsCacheItem *first;
assert(c);
if (!i)
return;
first = hashmap_get(c->by_key, i->key);
LIST_REMOVE(by_key, first, i);
if (first)
assert_se(hashmap_replace(c->by_key, first->key, first) >= 0);
else
hashmap_remove(c->by_key, i->key);
prioq_remove(c->by_expiry, i, &i->prioq_idx);
dns_cache_item_free(i);
}
void dns_cache_flush(DnsCache *c) {
DnsCacheItem *i;
assert(c);
while ((i = hashmap_first(c->by_key)))
dns_cache_item_remove_and_free(c, i);
assert(hashmap_size(c->by_key) == 0);
assert(prioq_size(c->by_expiry) == 0);
hashmap_free(c->by_key);
c->by_key = NULL;
prioq_free(c->by_expiry);
c->by_expiry = NULL;
}
static void dns_cache_remove(DnsCache *c, DnsResourceKey *key) {
DnsCacheItem *i;
assert(c);
assert(key);
while ((i = hashmap_get(c->by_key, key)))
dns_cache_item_remove_and_free(c, i);
}
static void dns_cache_make_space(DnsCache *c, unsigned add) {
assert(c);
void dns_cache_prune(DnsCache *c) {
usec_t t = 0;
assert(c);
/* Remove all entries that are past their TTL */
for (;;) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
DnsCacheItem *i;
i = prioq_peek(c->by_expiry);
if (!i)
break;
if (t <= 0)
t = now(CLOCK_BOOTTIME);
if (i->until > t)
break;
/* Take an extra reference to the key so that it
* doesn't go away in the middle of the remove call */
key = dns_resource_key_ref(i->key);
dns_cache_remove(c, key);
}
}
static int dns_cache_item_prioq_compare_func(const void *a, const void *b) {
const DnsCacheItem *x = a, *y = b;
if (x->until < y->until)
return -1;
if (x->until > y->until)
return 1;
return 0;
}
static int dns_cache_init(DnsCache *c) {
int r;
assert(c);
r = prioq_ensure_allocated(&c->by_expiry, dns_cache_item_prioq_compare_func);
if (r < 0)
return r;
r = hashmap_ensure_allocated(&c->by_key, &dns_resource_key_hash_ops);
if (r < 0)
return r;
return r;
}
static int dns_cache_link_item(DnsCache *c, DnsCacheItem *i) {
DnsCacheItem *first;
int r;
assert(c);
assert(i);
r = prioq_put(c->by_expiry, i, &i->prioq_idx);
if (r < 0)
return r;
first = hashmap_get(c->by_key, i->key);
if (first) {
LIST_PREPEND(by_key, first, i);
assert_se(hashmap_replace(c->by_key, first->key, first) >= 0);
} else {
r = hashmap_put(c->by_key, i->key, i);
if (r < 0) {
prioq_remove(c->by_expiry, i, &i->prioq_idx);
return r;
}
}
return 0;
}
static DnsCacheItem* dns_cache_get(DnsCache *c, DnsResourceRecord *rr) {
DnsCacheItem *i;
assert(c);
assert(rr);
LIST_FOREACH(by_key, i, hashmap_get(c->by_key, rr->key))
if (i->rr && dns_resource_record_equal(i->rr, rr) > 0)
return i;
return NULL;
}
static void dns_cache_item_update_positive(DnsCache *c, DnsCacheItem *i, DnsResourceRecord *rr, usec_t timestamp) {
assert(c);
assert(i);
assert(rr);
i->type = DNS_CACHE_POSITIVE;
if (!i->by_key_prev) {
/* We are the first item in the list, we need to
* update the key used in the hashmap */
assert_se(hashmap_replace(c->by_key, rr->key, i) >= 0);
}
dns_resource_record_ref(rr);
dns_resource_record_unref(i->rr);
i->rr = rr;
dns_resource_key_unref(i->key);
i->key = dns_resource_key_ref(rr->key);
i->until = timestamp + MIN(rr->ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC);
prioq_reshuffle(c->by_expiry, i, &i->prioq_idx);
}
static int dns_cache_put_positive(
DnsCache *c,
DnsResourceRecord *rr,
usec_t timestamp,
int owner_family,
const union in_addr_union *owner_address) {
_cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL;
DnsCacheItem *existing;
int r;
assert(c);
assert(rr);
assert(owner_address);
/* New TTL is 0? Delete the entry... */
if (rr->ttl <= 0) {
dns_cache_remove(c, rr->key);
return 0;
}
if (rr->key->class == DNS_CLASS_ANY)
return 0;
if (rr->key->type == DNS_TYPE_ANY)
return 0;
/* Entry exists already? Update TTL and timestamp */
existing = dns_cache_get(c, rr);
if (existing) {
dns_cache_item_update_positive(c, existing, rr, timestamp);
return 0;
}
/* Otherwise, add the new RR */
r = dns_cache_init(c);
if (r < 0)
return r;
dns_cache_make_space(c, 1);
i = new0(DnsCacheItem, 1);
if (!i)
return -ENOMEM;
i->type = DNS_CACHE_POSITIVE;
i->key = dns_resource_key_ref(rr->key);
i->rr = dns_resource_record_ref(rr);
i->until = timestamp + MIN(i->rr->ttl * USEC_PER_SEC, CACHE_TTL_MAX_USEC);
i->prioq_idx = PRIOQ_IDX_NULL;
i->owner_family = owner_family;
i->owner_address = *owner_address;
r = dns_cache_link_item(c, i);
if (r < 0)
return r;
i = NULL;
return 0;
}
static int dns_cache_put_negative(
DnsCache *c,
DnsResourceKey *key,
int rcode,
usec_t timestamp,
uint32_t soa_ttl,
int owner_family,
const union in_addr_union *owner_address) {
_cleanup_(dns_cache_item_freep) DnsCacheItem *i = NULL;
int r;
assert(c);
assert(key);
assert(owner_address);
dns_cache_remove(c, key);
if (key->class == DNS_CLASS_ANY)
return 0;
if (key->type == DNS_TYPE_ANY)
return 0;
if (soa_ttl <= 0)
return 0;
if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN))
return 0;
r = dns_cache_init(c);
if (r < 0)
return r;
dns_cache_make_space(c, 1);
i = new0(DnsCacheItem, 1);
if (!i)
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;
r = dns_cache_link_item(c, i);
if (r < 0)
return r;
i = NULL;
return 0;
}
int dns_cache_put(
DnsCache *c,
DnsQuestion *q,
int rcode,
DnsAnswer *answer,
unsigned max_rrs,
usec_t timestamp,
int owner_family,
const union in_addr_union *owner_address) {
unsigned i;
int r;
assert(c);
assert(q);