along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
+#include "af-list.h"
+
#include "resolved-dns-query.h"
#include "resolved-dns-domain.h"
-#define TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+/* After how much time to repeat classic DNS requests */
+#define DNS_TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+
+/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
+#define LLMNR_TRANSACTION_TIMEOUT_USEC (1 * USEC_PER_SEC)
+
+/* How long to wait for the query in total */
#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
-#define ATTEMPTS_MAX 8
+
+/* Maximum attempts to send DNS requests, across all DNS servers */
+#define DNS_TRANSACTION_ATTEMPTS_MAX 8
+
+/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
+#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
+
#define CNAME_MAX 8
#define QUERIES_MAX 2048
+#define TRANSACTION_TIMEOUT_USEC(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_TIMEOUT_USEC : DNS_TRANSACTION_TIMEOUT_USEC)
+#define TRANSACTION_ATTEMPTS_MAX(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)
+
static int dns_query_transaction_go(DnsQueryTransaction *t);
DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) {
* should hence not attempt to access the query or transaction
* after calling this function. */
+ log_debug("Transaction on scope %s on %s/%s now complete with %s",
+ dns_protocol_to_string(t->scope->protocol),
+ t->scope->link ? t->scope->link->name : "*",
+ t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family),
+ dns_query_state_to_string(state));
+
t->state = state;
dns_query_transaction_stop(t);
if (p->family != t->scope->family)
return;
- if (p->ipproto == IPPROTO_UDP) {
- if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
- return;
+ /* Tentative replies shall be discarded, see RFC 4795,
+ * 2.1.1 */
- if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
- return;
- }
+ if (DNS_PACKET_T(p))
+ return;
}
if (t->scope->protocol == DNS_PROTOCOL_DNS) {
return;
}
- dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, 0);
+ /* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
+ dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0);
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
dns_query_transaction_complete(t, DNS_QUERY_SUCCESS);
}
static int dns_query_transaction_go(DnsQueryTransaction *t) {
+ bool had_stream;
int r;
assert(t);
+ had_stream = !!t->stream;
+
dns_query_transaction_stop(t);
- if (t->n_attempts >= ATTEMPTS_MAX) {
+ log_debug("Beginning transaction on scope %s on %s/%s",
+ dns_protocol_to_string(t->scope->protocol),
+ t->scope->link ? t->scope->link->name : "*",
+ t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family));
+
+ if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t)) {
+ dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
+ return 0;
+ }
+
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR && had_stream) {
+ /* If we already tried via a stream, then we don't
+ * retry on LLMNR. See RFC 4795, Section 2.7. */
dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
return 0;
}
return dns_query_transaction_go(t);
}
- r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t);
+ r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC(t), 0, on_transaction_timeout, t);
if (r < 0)
return r;
q->question = dns_question_ref(question);
for (i = 0; i < question->n_keys; i++) {
- log_debug("Looking up RR for %s %s %s",
- strna(dns_class_to_string(question->keys[i]->class)),
- strna(dns_type_to_string(question->keys[i]->type)),
- DNS_RESOURCE_KEY_NAME(question->keys[i]));
+ _cleanup_free_ char *p;
+
+ r = dns_resource_key_to_string(question->keys[i], &p);
+ if (r < 0)
+ return r;
+
+ log_debug("Looking up RR for %s", p);
}
LIST_PREPEND(queries, m->dns_queries, q);
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
int rcode = 0;
DnsScope *scope = NULL;
+ bool pending = false;
Iterator i;
assert(q);
if (state == DNS_QUERY_SUCCESS && t->scope != scope)
continue;
- /* One of the transactions is still going on, let's wait for it */
- if (t->state == DNS_QUERY_PENDING || t->state == DNS_QUERY_NULL)
- return;
+ /* One of the transactions is still going on, let's maybe wait for it */
+ if (IN_SET(t->state, DNS_QUERY_PENDING, DNS_QUERY_NULL)) {
+ pending = true;
+ continue;
+ }
/* One of the transactions is successful, let's use
* it, and copy its data out */
state = t->state;
}
+ if (pending) {
+
+ /* If so far we weren't successful, and there's
+ * something still pending, then wait for it */
+ if (state != DNS_QUERY_SUCCESS)
+ return;
+
+ /* If we already were successful, then only wait for
+ * other transactions on the same scope to finish. */
+ SET_FOREACH(t, q->transactions, i) {
+ if (t->scope == scope && IN_SET(t->state, DNS_QUERY_PENDING, DNS_QUERY_NULL))
+ return;
+ }
+ }
+
if (IN_SET(state, DNS_QUERY_SUCCESS, DNS_QUERY_FAILURE)) {
q->answer = dns_answer_ref(answer);
q->answer_rcode = rcode;
return 0;
}
+
+static const char* const dns_query_state_table[_DNS_QUERY_STATE_MAX] = {
+ [DNS_QUERY_NULL] = "null",
+ [DNS_QUERY_PENDING] = "pending",
+ [DNS_QUERY_FAILURE] = "failure",
+ [DNS_QUERY_SUCCESS] = "success",
+ [DNS_QUERY_NO_SERVERS] = "no-servers",
+ [DNS_QUERY_TIMEOUT] = "timeout",
+ [DNS_QUERY_ATTEMPTS_MAX] = "attempts-max",
+ [DNS_QUERY_INVALID_REPLY] = "invalid-reply",
+ [DNS_QUERY_RESOURCES] = "resources",
+ [DNS_QUERY_ABORTED] = "aborted",
+};
+DEFINE_STRING_TABLE_LOOKUP(dns_query_state, DnsQueryState);
~ianmdlvl / elogind.git / blobdiff