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);
return 0;
}
+ t->block_gc++;
dns_query_transaction_process_reply(t, p);
+ t->block_gc--;
+
+ /* If the response wasn't useful, then complete the transition now */
+ if (t->state == DNS_QUERY_PENDING)
+ dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY);
+
return 0;
}
if (t->scope->protocol == DNS_PROTOCOL_DNS)
fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53);
else if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
- if (!t->received)
- return -EINVAL;
- fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port);
+ /* When we already received a query to this (but it was truncated), send to its sender address */
+ if (t->received)
+ fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port);
+ else {
+ union in_addr_union address;
+ int family;
+
+ /* Otherwise, try to talk to the owner of a
+ * the IP address, in case this is a reverse
+ * PTR lookup */
+ r = dns_question_extract_reverse_address(t->question, &family, &address);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EINVAL;
+
+ fd = dns_scope_tcp_socket(t->scope, family, &address, 5355);
+ }
} else
return -EAFNOSUPPORT;
t->received = dns_packet_unref(t->received);
t->stream->complete = on_stream_complete;
+ t->stream->transaction = t;
+
+ /* The interface index is difficult to determine if we are
+ * connecting to the local host, hence fill this in right away
+ * instead of determining it from the socket */
+ if (t->scope->link)
+ t->stream->ifindex = t->scope->link->ifindex;
return 0;
}
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;
}
if (r < 0)
return r;
- /* Try via UDP, and if that fails due to large size try via TCP */
- r = dns_scope_send(t->scope, t->sent);
- if (r == -EMSGSIZE)
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR &&
+ (dns_question_endswith(t->question, "in-addr.arpa") > 0 ||
+ dns_question_endswith(t->question, "ip6.arpa") > 0)) {
+
+ /* RFC 4795, Section 2.4. says reverse lookups shall
+ * always be made via TCP on LLMNR */
r = dns_query_transaction_open_tcp(t);
+ } else {
+ /* Try via UDP, and if that fails due to large size try via TCP */
+ r = dns_scope_send(t->scope, t->sent);
+ if (r == -EMSGSIZE)
+ r = dns_query_transaction_open_tcp(t);
+ }
if (r == -ESRCH) {
/* No servers to send this to? */
dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS);
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;
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