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Diffstat (limited to 'src/resolve/resolved-dns-cache.c')
-rw-r--r--src/resolve/resolved-dns-cache.c194
1 files changed, 125 insertions, 69 deletions
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 81ea1cafcb..ef6b69c768 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -411,22 +411,23 @@ int dns_cache_put(
int owner_family,
const union in_addr_union *owner_address) {
- unsigned i;
+ unsigned cache_keys, i;
int r;
assert(c);
- assert(q);
- /* First, delete all matching old RRs, so that we only keep
- * complete by_key in place. */
- for (i = 0; i < q->n_keys; i++)
- dns_cache_remove(c, q->keys[i]);
+ if (q) {
+ /* First, if we were passed a question, delete all matching old RRs,
+ * so that we only keep complete by_key in place. */
+ for (i = 0; i < q->n_keys; i++)
+ dns_cache_remove(c, q->keys[i]);
+ }
if (!answer)
return 0;
for (i = 0; i < answer->n_rrs; i++)
- dns_cache_remove(c, answer->rrs[i]->key);
+ dns_cache_remove(c, answer->items[i].rr->key);
/* We only care for positive replies and NXDOMAINs, on all
* other replies we will simply flush the respective entries,
@@ -435,19 +436,27 @@ int dns_cache_put(
if (!IN_SET(rcode, DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN))
return 0;
+ cache_keys = answer->n_rrs;
+
+ if (q)
+ cache_keys += q->n_keys;
+
/* Make some space for our new entries */
- dns_cache_make_space(c, answer->n_rrs + q->n_keys);
+ dns_cache_make_space(c, cache_keys);
if (timestamp <= 0)
timestamp = now(clock_boottime_or_monotonic());
/* Second, add in positive entries for all contained RRs */
for (i = 0; i < MIN(max_rrs, answer->n_rrs); i++) {
- r = dns_cache_put_positive(c, answer->rrs[i], timestamp, owner_family, owner_address);
+ r = dns_cache_put_positive(c, answer->items[i].rr, timestamp, owner_family, owner_address);
if (r < 0)
goto fail;
}
+ if (!q)
+ return 0;
+
/* Third, add in negative entries for all keys with no RR */
for (i = 0; i < q->n_keys; i++) {
DnsResourceRecord *soa = NULL;
@@ -458,6 +467,10 @@ int dns_cache_put(
if (r > 0)
continue;
+ /* See https://tools.ietf.org/html/rfc2308, which
+ * say that a matching SOA record in the packet
+ * is used to to enable negative caching. */
+
r = dns_answer_find_soa(answer, q->keys[i], &soa);
if (r < 0)
goto fail;
@@ -475,80 +488,76 @@ fail:
/* Adding all RRs failed. Let's clean up what we already
* added, just in case */
- for (i = 0; i < q->n_keys; i++)
- dns_cache_remove(c, q->keys[i]);
+ if (q) {
+ for (i = 0; i < q->n_keys; i++)
+ dns_cache_remove(c, q->keys[i]);
+ }
+
for (i = 0; i < answer->n_rrs; i++)
- dns_cache_remove(c, answer->rrs[i]->key);
+ dns_cache_remove(c, answer->items[i].rr->key);
return r;
}
-int dns_cache_lookup(DnsCache *c, DnsQuestion *q, int *rcode, DnsAnswer **ret) {
+int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **ret) {
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- unsigned i, n = 0;
+ unsigned n = 0;
int r;
bool nxdomain = false;
+ _cleanup_free_ char *key_str = NULL;
+ DnsCacheItem *j, *first;
assert(c);
- assert(q);
+ assert(key);
assert(rcode);
assert(ret);
- if (q->n_keys <= 0) {
- *ret = NULL;
- *rcode = 0;
- return 0;
- }
+ if (key->type == DNS_TYPE_ANY ||
+ key->class == DNS_CLASS_ANY) {
- for (i = 0; i < q->n_keys; i++) {
- _cleanup_free_ char *key_str = NULL;
- DnsCacheItem *j;
+ /* If we have ANY lookups we simply refresh */
- if (q->keys[i]->type == DNS_TYPE_ANY ||
- q->keys[i]->class == DNS_CLASS_ANY) {
- /* If we have ANY lookups we simply refresh */
+ r = dns_resource_key_to_string(key, &key_str);
+ if (r < 0)
+ return r;
- r = dns_resource_key_to_string(q->keys[i], &key_str);
- if (r < 0)
- return r;
+ log_debug("Ignoring cache for ANY lookup: %s", key_str);
- log_debug("Ignoring cache for ANY lookup: %s", key_str);
+ *ret = NULL;
+ *rcode = DNS_RCODE_SUCCESS;
+ return 0;
+ }
- *ret = NULL;
- *rcode = 0;
- return 0;
- }
+ first = hashmap_get(c->by_key, key);
+ if (!first) {
+ /* If one question cannot be answered we need to refresh */
- j = hashmap_get(c->by_key, q->keys[i]);
- if (!j) {
- /* If one question cannot be answered we need to refresh */
+ r = dns_resource_key_to_string(key, &key_str);
+ if (r < 0)
+ return r;
- r = dns_resource_key_to_string(q->keys[i], &key_str);
- if (r < 0)
- return r;
+ log_debug("Cache miss for %s", key_str);
- log_debug("Cache miss for %s", key_str);
+ *ret = NULL;
+ *rcode = DNS_RCODE_SUCCESS;
+ return 0;
+ }
- *ret = NULL;
- *rcode = 0;
- return 0;
- } else {
- r = dns_resource_key_to_string(j->key, &key_str);
- if (r < 0)
- return r;
+ LIST_FOREACH(by_key, j, first) {
+ if (j->rr)
+ n++;
+ else if (j->type == DNS_CACHE_NXDOMAIN)
+ nxdomain = true;
+ }
- log_debug("%s cache hit for %s",
- j->type == DNS_CACHE_POSITIVE ? "Positive" :
- (j->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN"), key_str);
- }
+ r = dns_resource_key_to_string(key, &key_str);
+ if (r < 0)
+ return r;
- LIST_FOREACH(by_key, j, j) {
- if (j->rr)
- n++;
- else if (j->type == DNS_CACHE_NXDOMAIN)
- nxdomain = true;
- }
- }
+ log_debug("%s cache hit for %s",
+ nxdomain ? "NXDOMAIN" :
+ n > 0 ? "Positive" : "NODATA",
+ key_str);
if (n <= 0) {
*ret = NULL;
@@ -560,17 +569,13 @@ int dns_cache_lookup(DnsCache *c, DnsQuestion *q, int *rcode, DnsAnswer **ret) {
if (!answer)
return -ENOMEM;
- for (i = 0; i < q->n_keys; i++) {
- DnsCacheItem *j;
+ LIST_FOREACH(by_key, j, first) {
+ if (!j->rr)
+ continue;
- j = hashmap_get(c->by_key, q->keys[i]);
- LIST_FOREACH(by_key, j, j) {
- if (j->rr) {
- r = dns_answer_add(answer, j->rr);
- if (r < 0)
- return r;
- }
- }
+ r = dns_answer_add(answer, j->rr, 0);
+ if (r < 0)
+ return r;
}
*ret = answer;
@@ -615,3 +620,54 @@ int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_
/* There's a conflict */
return 1;
}
+
+void dns_cache_dump(DnsCache *cache, FILE *f) {
+ Iterator iterator;
+ DnsCacheItem *i;
+ int r;
+
+ if (!cache)
+ return;
+
+ if (!f)
+ f = stdout;
+
+ HASHMAP_FOREACH(i, cache->by_key, iterator) {
+ DnsCacheItem *j;
+
+ LIST_FOREACH(by_key, j, i) {
+ _cleanup_free_ char *t = NULL;
+
+ fputc('\t', f);
+
+ if (j->rr) {
+ r = dns_resource_record_to_string(j->rr, &t);
+ if (r < 0) {
+ log_oom();
+ continue;
+ }
+
+ fputs(t, f);
+ fputc('\n', f);
+ } else {
+ r = dns_resource_key_to_string(j->key, &t);
+ if (r < 0) {
+ log_oom();
+ continue;
+ }
+
+ fputs(t, f);
+ fputs(" -- ", f);
+ fputs(j->type == DNS_CACHE_NODATA ? "NODATA" : "NXDOMAIN", f);
+ fputc('\n', f);
+ }
+ }
+ }
+}
+
+bool dns_cache_is_empty(DnsCache *cache) {
+ if (!cache)
+ return true;
+
+ return hashmap_isempty(cache->by_key);
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-03 10:18:50 +0000