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)
+/* How long to wait for the query in total */
#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
-#define ATTEMPTS_MAX 8
-DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) {
- if (!t)
+#define CNAME_MAX 8
+#define QUERIES_MAX 2048
+
+static void dns_query_stop(DnsQuery *q) {
+ DnsTransaction *t;
+
+ assert(q);
+
+ q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+
+ while ((t = set_steal_first(q->transactions))) {
+ set_remove(t->queries, q);
+ dns_transaction_gc(t);
+ }
+}
+
+DnsQuery *dns_query_free(DnsQuery *q) {
+ if (!q)
return NULL;
- sd_event_source_unref(t->timeout_event_source);
- dns_packet_unref(t->packet);
+ dns_query_stop(q);
+ set_free(q->transactions);
+
+ dns_question_unref(q->question);
+ dns_answer_unref(q->answer);
- if (t->query) {
- LIST_REMOVE(transactions_by_query, t->query->transactions, t);
- hashmap_remove(t->query->manager->dns_query_transactions, UINT_TO_PTR(t->id));
+ sd_bus_message_unref(q->request);
+ sd_bus_track_unref(q->bus_track);
+
+ if (q->manager) {
+ LIST_REMOVE(queries, q->manager->dns_queries, q);
+ q->manager->n_dns_queries--;
}
- if (t->scope)
- LIST_REMOVE(transactions_by_scope, t->scope->transactions, t);
+ free(q);
- free(t);
return NULL;
}
-DEFINE_TRIVIAL_CLEANUP_FUNC(DnsQueryTransaction*, dns_query_transaction_free);
-
-static int dns_query_transaction_new(DnsQuery *q, DnsQueryTransaction **ret, DnsScope *s) {
- _cleanup_(dns_query_transaction_freep) DnsQueryTransaction *t = NULL;
+int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex, uint64_t flags) {
+ _cleanup_(dns_query_freep) DnsQuery *q = NULL;
+ unsigned i;
int r;
- assert(q);
- assert(s);
+ assert(m);
+ assert(question);
- r = hashmap_ensure_allocated(&q->manager->dns_query_transactions, NULL, NULL);
+ r = dns_question_is_valid(question);
if (r < 0)
return r;
- t = new0(DnsQueryTransaction, 1);
- if (!t)
+ if (m->n_dns_queries >= QUERIES_MAX)
+ return -EBUSY;
+
+ q = new0(DnsQuery, 1);
+ if (!q)
return -ENOMEM;
- do
- random_bytes(&t->id, sizeof(t->id));
- while (t->id == 0 ||
- hashmap_get(q->manager->dns_query_transactions, UINT_TO_PTR(t->id)));
+ q->question = dns_question_ref(question);
+ q->ifindex = ifindex;
+ q->flags = flags;
- r = hashmap_put(q->manager->dns_query_transactions, UINT_TO_PTR(t->id), t);
- if (r < 0) {
- t->id = 0;
- return r;
- }
+ for (i = 0; i < question->n_keys; i++) {
+ _cleanup_free_ char *p;
+
+ r = dns_resource_key_to_string(question->keys[i], &p);
+ if (r < 0)
+ return r;
- LIST_PREPEND(transactions_by_query, q->transactions, t);
- t->query = q;
+ log_debug("Looking up RR for %s", p);
+ }
- LIST_PREPEND(transactions_by_scope, s->transactions, t);
- t->scope = s;
+ LIST_PREPEND(queries, m->dns_queries, q);
+ m->n_dns_queries++;
+ q->manager = m;
if (ret)
- *ret = t;
-
- t = NULL;
+ *ret = q;
+ q = NULL;
return 0;
}
-static void dns_query_transaction_set_state(DnsQueryTransaction *t, DnsQueryState state) {
- assert(t);
-
- if (t->state == state)
- return;
+static void dns_query_complete(DnsQuery *q, DnsTransactionState state) {
+ assert(q);
+ assert(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
+ assert(IN_SET(q->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
- t->state = state;
+ /* Note that this call might invalidate the query. Callers
+ * should hence not attempt to access the query or transaction
+ * after calling this function. */
- if (state != DNS_QUERY_SENT)
- t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
+ q->state = state;
- dns_query_finish(t->query);
+ dns_query_stop(q);
+ if (q->complete)
+ q->complete(q);
}
-int dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p) {
- assert(t);
- assert(p);
-
- t->packet = dns_packet_ref(p);
+static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) {
+ DnsQuery *q = userdata;
- if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
- dns_query_transaction_set_state(t, DNS_QUERY_SUCCESS);
- else
- dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
+ assert(s);
+ assert(q);
+ dns_query_complete(q, DNS_TRANSACTION_TIMEOUT);
return 0;
}
-static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) {
- DnsQueryTransaction *t = userdata;
+static int dns_query_add_transaction(DnsQuery *q, DnsScope *s, DnsResourceKey *key) {
+ _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
+ DnsTransaction *t;
int r;
+ assert(q);
assert(s);
- assert(t);
-
- /* Timeout reached? Try again, with a new server */
- dns_scope_next_dns_server(t->scope);
- r = dns_query_transaction_start(t);
+ r = set_ensure_allocated(&q->transactions, NULL);
if (r < 0)
- dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
-
- return 0;
-}
-
-int dns_query_transaction_start(DnsQueryTransaction *t) {
- _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
- unsigned n;
- int r;
-
- assert(t);
-
- t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
-
- if (t->n_attempts >= ATTEMPTS_MAX) {
- dns_query_transaction_set_state(t, DNS_QUERY_ATTEMPTS_MAX);
- return 0;
- }
+ return r;
- t->n_attempts++;
+ if (key) {
+ question = dns_question_new(1);
+ if (!question)
+ return -ENOMEM;
- r = dns_packet_new_query(&p, 0);
- if (r < 0)
- return r;
+ r = dns_question_add(question, key);
+ if (r < 0)
+ return r;
+ } else
+ question = dns_question_ref(q->question);
- for (n = 0; n < t->query->n_keys; n++) {
- r = dns_packet_append_key(p, &t->query->keys[n], NULL);
+ t = dns_scope_find_transaction(s, question, true);
+ if (!t) {
+ r = dns_transaction_new(&t, s, question);
if (r < 0)
return r;
}
- DNS_PACKET_HEADER(p)->qdcount = htobe16(t->query->n_keys);
- DNS_PACKET_HEADER(p)->id = t->id;
+ r = set_ensure_allocated(&t->queries, NULL);
+ if (r < 0)
+ goto gc;
- r = dns_scope_send(t->scope, p);
- if (r < 0) {
- /* Couldn't send? Try immediately again, with a new server */
- dns_scope_next_dns_server(t->scope);
+ r = set_put(t->queries, q);
+ if (r < 0)
+ goto gc;
- return dns_query_transaction_start(t);
+ r = set_put(q->transactions, t);
+ if (r < 0) {
+ set_remove(t->queries, q);
+ goto gc;
}
- if (r > 0) {
- int q;
-
- q = sd_event_add_time(t->query->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t);
- if (q < 0)
- return q;
-
- dns_query_transaction_set_state(t, DNS_QUERY_SENT);
- } else
- dns_query_transaction_set_state(t, DNS_QUERY_SKIPPED);
+ return 0;
+gc:
+ dns_transaction_gc(t);
return r;
}
-DnsQuery *dns_query_free(DnsQuery *q) {
- unsigned n;
-
- if (!q)
- return NULL;
+static int dns_query_add_transaction_split(DnsQuery *q, DnsScope *s) {
+ int r;
- sd_bus_message_unref(q->request);
- dns_packet_unref(q->packet);
- sd_event_source_unref(q->timeout_event_source);
+ assert(q);
+ assert(s);
- while (q->transactions)
- dns_query_transaction_free(q->transactions);
+ if (s->protocol == DNS_PROTOCOL_MDNS) {
+ r = dns_query_add_transaction(q, s, NULL);
+ if (r < 0)
+ return r;
+ } else {
+ unsigned i;
- if (q->manager)
- LIST_REMOVE(queries, q->manager->dns_queries, q);
+ /* On DNS and LLMNR we can only send a single
+ * question per datagram, hence issue multiple
+ * transactions. */
- for (n = 0; n < q->n_keys; n++)
- free(q->keys[n].name);
- free(q->keys);
- free(q);
+ for (i = 0; i < q->question->n_keys; i++) {
+ r = dns_query_add_transaction(q, s, q->question->keys[i]);
+ if (r < 0)
+ return r;
+ }
+ }
- return NULL;
+ return 0;
}
-int dns_query_new(Manager *m, DnsQuery **ret, DnsResourceKey *keys, unsigned n_keys) {
- _cleanup_(dns_query_freep) DnsQuery *q = NULL;
- DnsScope *s, *first = NULL;
+int dns_query_go(DnsQuery *q) {
DnsScopeMatch found = DNS_SCOPE_NO;
- const char *name = NULL;
- int n, r;
-
- assert(m);
-
- if (n_keys <= 0 || n_keys >= 65535)
- return -EINVAL;
-
- assert(keys);
+ DnsScope *s, *first = NULL;
+ DnsTransaction *t;
+ const char *name;
+ Iterator i;
+ int r;
- q = new0(DnsQuery, 1);
- if (!q)
- return -ENOMEM;
+ assert(q);
- q->keys = new(DnsResourceKey, n_keys);
- if (!q->keys)
- return -ENOMEM;
+ if (q->state != DNS_TRANSACTION_NULL)
+ return 0;
- for (q->n_keys = 0; q->n_keys < n_keys; q->n_keys++) {
- q->keys[q->n_keys].class = keys[q->n_keys].class;
- q->keys[q->n_keys].type = keys[q->n_keys].type;
- q->keys[q->n_keys].name = strdup(keys[q->n_keys].name);
- if (!q->keys[q->n_keys].name)
- return -ENOMEM;
+ assert(q->question);
+ assert(q->question->n_keys > 0);
- if (!name)
- name = q->keys[q->n_keys].name;
- else if (!dns_name_equal(name, q->keys[q->n_keys].name))
- return -EINVAL;
- }
+ name = DNS_RESOURCE_KEY_NAME(q->question->keys[0]);
- LIST_PREPEND(queries, m->dns_queries, q);
- q->manager = m;
-
- LIST_FOREACH(scopes, s, m->dns_scopes) {
+ LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
DnsScopeMatch match;
- match = dns_scope_test(s, name);
+ match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
if (match < 0)
return match;
}
if (found == DNS_SCOPE_NO)
- return -ENETDOWN;
+ return -ESRCH;
- r = dns_query_transaction_new(q, NULL, first);
+ r = dns_query_add_transaction_split(q, first);
if (r < 0)
- return r;
+ goto fail;
- n = 1;
LIST_FOREACH(scopes, s, first->scopes_next) {
DnsScopeMatch match;
- match = dns_scope_test(s, name);
+ match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
if (match < 0)
- return match;
+ goto fail;
if (match != found)
continue;
- r = dns_query_transaction_new(q, NULL, s);
+ r = dns_query_add_transaction_split(q, s);
if (r < 0)
- return r;
+ goto fail;
+ }
- n++;
+ q->answer = dns_answer_unref(q->answer);
+ q->answer_ifindex = 0;
+ q->answer_rcode = 0;
+ q->answer_family = AF_UNSPEC;
+ q->answer_protocol = _DNS_PROTOCOL_INVALID;
+
+ r = sd_event_add_time(
+ q->manager->event,
+ &q->timeout_event_source,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + QUERY_TIMEOUT_USEC, 0,
+ on_query_timeout, q);
+ if (r < 0)
+ goto fail;
+
+ q->state = DNS_TRANSACTION_PENDING;
+ q->block_ready++;
+
+ /* Start the transactions that are not started yet */
+ SET_FOREACH(t, q->transactions, i) {
+ if (t->state != DNS_TRANSACTION_NULL)
+ continue;
+
+ r = dns_transaction_go(t);
+ if (r < 0)
+ goto fail;
}
- if (ret)
- *ret = q;
- q = NULL;
+ q->block_ready--;
+ dns_query_ready(q);
- return n;
+ return 1;
+
+fail:
+ dns_query_stop(q);
+ return r;
}
-static void dns_query_set_state(DnsQuery *q, DnsQueryState state) {
+void dns_query_ready(DnsQuery *q) {
+ DnsTransaction *t;
+ DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ int rcode = 0;
+ DnsScope *scope = NULL;
+ bool pending = false;
+ Iterator i;
+
assert(q);
+ assert(IN_SET(q->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
+
+ /* Note that this call might invalidate the query. Callers
+ * should hence not attempt to access the query or transaction
+ * after calling this function, unless the block_ready
+ * counter was explicitly bumped before doing so. */
- if (q->state == state)
+ if (q->block_ready > 0)
return;
- q->state = state;
+ SET_FOREACH(t, q->transactions, i) {
- if (state == DNS_QUERY_SENT)
- return;
+ /* If we found a successful answer, ignore all answers from other scopes */
+ if (state == DNS_TRANSACTION_SUCCESS && t->scope != scope)
+ continue;
- q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+ /* One of the transactions is still going on, let's maybe wait for it */
+ if (IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_NULL)) {
+ pending = true;
+ continue;
+ }
- while (q->transactions)
- dns_query_transaction_free(q->transactions);
+ /* One of the transactions is successful, let's use
+ * it, and copy its data out */
+ if (t->state == DNS_TRANSACTION_SUCCESS) {
+ DnsAnswer *a;
+
+ if (t->received) {
+ rcode = DNS_PACKET_RCODE(t->received);
+ a = t->received->answer;
+ } else {
+ rcode = t->cached_rcode;
+ a = t->cached;
+ }
+
+ if (state == DNS_TRANSACTION_SUCCESS) {
+ DnsAnswer *merged;
+
+ merged = dns_answer_merge(answer, a);
+ if (!merged) {
+ dns_query_complete(q, DNS_TRANSACTION_RESOURCES);
+ return;
+ }
+
+ dns_answer_unref(answer);
+ answer = merged;
+ } else {
+ dns_answer_unref(answer);
+ answer = dns_answer_ref(a);
+ }
+
+ scope = t->scope;
+ state = DNS_TRANSACTION_SUCCESS;
+ continue;
+ }
- if (q->complete)
- q->complete(q);
-}
+ /* One of the transactions has failed, let's see
+ * whether we find anything better, but if not, return
+ * its response data */
+ if (state != DNS_TRANSACTION_SUCCESS && t->state == DNS_TRANSACTION_FAILURE) {
+ DnsAnswer *a;
+
+ if (t->received) {
+ rcode = DNS_PACKET_RCODE(t->received);
+ a = t->received->answer;
+ } else {
+ rcode = t->cached_rcode;
+ a = t->cached;
+ }
+
+ dns_answer_unref(answer);
+ answer = dns_answer_ref(a);
+
+ scope = t->scope;
+ state = DNS_TRANSACTION_FAILURE;
+ continue;
+ }
-static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) {
- DnsQuery *q = userdata;
+ if (state == DNS_TRANSACTION_NO_SERVERS && t->state != DNS_TRANSACTION_NO_SERVERS)
+ state = t->state;
+ }
- assert(s);
- assert(q);
+ if (pending) {
- dns_query_set_state(q, DNS_QUERY_TIMEOUT);
- return 0;
+ /* If so far we weren't successful, and there's
+ * something still pending, then wait for it */
+ if (state != DNS_TRANSACTION_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_TRANSACTION_PENDING, DNS_TRANSACTION_NULL))
+ return;
+ }
+ }
+
+ if (IN_SET(state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE)) {
+ q->answer = dns_answer_ref(answer);
+ q->answer_rcode = rcode;
+ q->answer_ifindex = (scope && scope->link) ? scope->link->ifindex : 0;
+ q->answer_protocol = scope ? scope->protocol : _DNS_PROTOCOL_INVALID;
+ q->answer_family = scope ? scope->family : AF_UNSPEC;
+ }
+
+ dns_query_complete(q, state);
}
-int dns_query_start(DnsQuery *q) {
- DnsQueryTransaction *t;
+int dns_query_cname_redirect(DnsQuery *q, const char *name) {
+ _cleanup_(dns_question_unrefp) DnsQuestion *nq = NULL;
int r;
assert(q);
- assert(q->state == DNS_QUERY_NULL);
- if (!q->transactions)
- return -ENETDOWN;
+ if (q->n_cname_redirects > CNAME_MAX)
+ return -ELOOP;
- r = sd_event_add_time(q->manager->event, &q->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + QUERY_TIMEOUT_USEC, 0, on_query_timeout, q);
+ r = dns_question_cname_redirect(q->question, name, &nq);
if (r < 0)
- goto fail;
-
- dns_query_set_state(q, DNS_QUERY_SENT);
+ return r;
- LIST_FOREACH(transactions_by_query, t, q->transactions) {
+ dns_question_unref(q->question);
+ q->question = nq;
+ nq = NULL;
- r = dns_query_transaction_start(t);
- if (r < 0)
- goto fail;
+ q->n_cname_redirects++;
- if (q->state != DNS_QUERY_SENT)
- break;
- }
+ dns_query_stop(q);
+ q->state = DNS_TRANSACTION_NULL;
return 0;
-
-fail:
- while (q->transactions)
- dns_query_transaction_free(q->transactions);
-
- return r;
}
-void dns_query_finish(DnsQuery *q) {
- DnsQueryTransaction *t;
- DnsQueryState state = DNS_QUERY_SKIPPED;
- uint16_t rcode = 0;
+static int on_bus_track(sd_bus_track *t, void *userdata) {
+ DnsQuery *q = userdata;
+ assert(t);
assert(q);
- if (q->state != DNS_QUERY_SENT)
- return;
-
- LIST_FOREACH(transactions_by_query, t, q->transactions) {
-
- /* One of the transactions is still going on, let's wait for it */
- if (t->state == DNS_QUERY_SENT || t->state == DNS_QUERY_NULL)
- return;
-
- /* One of the transactions is sucecssful, let's use it */
- if (t->state == DNS_QUERY_SUCCESS) {
- q->packet = dns_packet_ref(t->packet);
- dns_query_set_state(q, DNS_QUERY_SUCCESS);
- return;
- }
+ log_debug("Client of active query vanished, aborting query.");
+ dns_query_complete(q, DNS_TRANSACTION_ABORTED);
+ return 0;
+}
- if (t->state == DNS_QUERY_FAILURE) {
- state = DNS_QUERY_FAILURE;
+int dns_query_bus_track(DnsQuery *q, sd_bus *bus, sd_bus_message *m) {
+ int r;
- if (rcode == 0 && t->packet)
- rcode = DNS_PACKET_RCODE(t->packet);
+ assert(q);
+ assert(m);
- } else if (state == DNS_QUERY_SKIPPED && t->state != DNS_QUERY_SKIPPED)
- state = t->state;
+ if (!q->bus_track) {
+ r = sd_bus_track_new(bus, &q->bus_track, on_bus_track, q);
+ if (r < 0)
+ return r;
}
- if (state == DNS_QUERY_FAILURE)
- q->rcode = rcode;
+ r = sd_bus_track_add_sender(q->bus_track, m);
+ if (r < 0)
+ return r;
- dns_query_set_state(q, state);
+ return 0;
}