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-rw-r--r--src/resolve/resolved-dns-query.c408
1 files changed, 408 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
new file mode 100644
index 0000000000..a9880524e6
--- /dev/null
+++ b/src/resolve/resolved-dns-query.c
@@ -0,0 +1,408 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "resolved-dns-query.h"
+#include "resolved-dns-domain.h"
+
+#define TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
+#define ATTEMPTS_MAX 8
+
+DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) {
+ if (!t)
+ return NULL;
+
+ sd_event_source_unref(t->timeout_event_source);
+ dns_packet_unref(t->packet);
+
+ 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));
+ }
+
+ if (t->scope)
+ LIST_REMOVE(transactions_by_scope, t->scope->transactions, t);
+
+ 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 r;
+
+ assert(q);
+ assert(s);
+
+ r = hashmap_ensure_allocated(&q->manager->dns_query_transactions, NULL, NULL);
+ if (r < 0)
+ return r;
+
+ t = new0(DnsQueryTransaction, 1);
+ if (!t)
+ 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)));
+
+ r = hashmap_put(q->manager->dns_query_transactions, UINT_TO_PTR(t->id), t);
+ if (r < 0) {
+ t->id = 0;
+ return r;
+ }
+
+ LIST_PREPEND(transactions_by_query, q->transactions, t);
+ t->query = q;
+
+ LIST_PREPEND(transactions_by_scope, s->transactions, t);
+ t->scope = s;
+
+ if (ret)
+ *ret = t;
+
+ t = NULL;
+
+ return 0;
+}
+
+static void dns_query_transaction_set_state(DnsQueryTransaction *t, DnsQueryState state) {
+ assert(t);
+
+ if (t->state == state)
+ return;
+
+ t->state = state;
+
+ if (state != DNS_QUERY_SENT)
+ t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
+
+ dns_query_finish(t->query);
+}
+
+int dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p) {
+ assert(t);
+ assert(p);
+
+ t->packet = dns_packet_ref(p);
+
+ if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS) {
+ if( be16toh(DNS_PACKET_HEADER(p)->ancount) > 0)
+ dns_query_transaction_set_state(t, DNS_QUERY_SUCCESS);
+ else
+ dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ } else
+ dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
+
+ return 0;
+}
+
+static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) {
+ DnsQueryTransaction *t = userdata;
+ int r;
+
+ 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);
+ 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;
+ }
+
+ t->n_attempts++;
+
+ r = dns_packet_new_query(&p, 0);
+ if (r < 0)
+ return r;
+
+ for (n = 0; n < t->query->n_keys; n++) {
+ r = dns_packet_append_key(p, &t->query->keys[n], NULL);
+ if (r < 0)
+ return r;
+ }
+
+ DNS_PACKET_HEADER(p)->qdcount = htobe16(t->query->n_keys);
+ DNS_PACKET_HEADER(p)->id = t->id;
+
+ 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);
+
+ return dns_query_transaction_start(t);
+ }
+
+ 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 r;
+}
+
+DnsQuery *dns_query_free(DnsQuery *q) {
+ unsigned n;
+
+ if (!q)
+ return NULL;
+
+ sd_bus_message_unref(q->request);
+ dns_packet_unref(q->packet);
+ sd_event_source_unref(q->timeout_event_source);
+
+ while (q->transactions)
+ dns_query_transaction_free(q->transactions);
+
+ if (q->manager)
+ LIST_REMOVE(queries, q->manager->dns_queries, q);
+
+ for (n = 0; n < q->n_keys; n++)
+ free(q->keys[n].name);
+ free(q->keys);
+ free(q);
+
+ return NULL;
+}
+
+int dns_query_new(Manager *m, DnsQuery **ret, DnsResourceKey *keys, unsigned n_keys) {
+ _cleanup_(dns_query_freep) DnsQuery *q = NULL;
+ DnsScope *s, *first = NULL;
+ 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);
+
+ q = new0(DnsQuery, 1);
+ if (!q)
+ return -ENOMEM;
+
+ q->keys = new(DnsResourceKey, n_keys);
+ if (!q->keys)
+ return -ENOMEM;
+
+ 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;
+
+ if (!name)
+ name = q->keys[q->n_keys].name;
+ else if (!dns_name_equal(name, q->keys[q->n_keys].name))
+ return -EINVAL;
+ }
+
+ LIST_PREPEND(queries, m->dns_queries, q);
+ q->manager = m;
+
+ LIST_FOREACH(scopes, s, m->dns_scopes) {
+ DnsScopeMatch match;
+
+ match = dns_scope_test(s, name);
+ if (match < 0)
+ return match;
+
+ if (match == DNS_SCOPE_NO)
+ continue;
+
+ found = match;
+
+ if (match == DNS_SCOPE_YES) {
+ first = s;
+ break;
+ } else {
+ assert(match == DNS_SCOPE_MAYBE);
+
+ if (!first)
+ first = s;
+ }
+ }
+
+ if (found == DNS_SCOPE_NO)
+ return -ENETDOWN;
+
+ r = dns_query_transaction_new(q, NULL, first);
+ if (r < 0)
+ return r;
+
+ n = 1;
+ LIST_FOREACH(scopes, s, first->scopes_next) {
+ DnsScopeMatch match;
+
+ match = dns_scope_test(s, name);
+ if (match < 0)
+ return match;
+
+ if (match != found)
+ continue;
+
+ r = dns_query_transaction_new(q, NULL, s);
+ if (r < 0)
+ return r;
+
+ n++;
+ }
+
+ if (ret)
+ *ret = q;
+ q = NULL;
+
+ return n;
+}
+
+static void dns_query_set_state(DnsQuery *q, DnsQueryState state) {
+ assert(q);
+
+ if (q->state == state)
+ return;
+
+ q->state = state;
+
+ if (state == DNS_QUERY_SENT)
+ return;
+
+ q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+
+ while (q->transactions)
+ dns_query_transaction_free(q->transactions);
+
+ if (q->complete)
+ q->complete(q);
+}
+
+static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) {
+ DnsQuery *q = userdata;
+
+ assert(s);
+ assert(q);
+
+ dns_query_set_state(q, DNS_QUERY_TIMEOUT);
+ return 0;
+}
+
+int dns_query_start(DnsQuery *q) {
+ DnsQueryTransaction *t;
+ int r;
+
+ assert(q);
+ assert(q->state == DNS_QUERY_NULL);
+
+ if (!q->transactions)
+ return -ENETDOWN;
+
+ 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);
+ if (r < 0)
+ goto fail;
+
+ dns_query_set_state(q, DNS_QUERY_SENT);
+
+ LIST_FOREACH(transactions_by_query, t, q->transactions) {
+
+ r = dns_query_transaction_start(t);
+ if (r < 0)
+ goto fail;
+
+ if (q->state != DNS_QUERY_SENT)
+ break;
+ }
+
+ 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;
+
+ 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;
+ }
+
+ if (t->state == DNS_QUERY_FAILURE) {
+ state = DNS_QUERY_FAILURE;
+
+ if (rcode == 0 && t->packet)
+ rcode = DNS_PACKET_RCODE(t->packet);
+
+ } else if (state == DNS_QUERY_SKIPPED && t->state != DNS_QUERY_SKIPPED)
+ state = t->state;
+ }
+
+ if (state == DNS_QUERY_FAILURE)
+ q->rcode = rcode;
+
+ dns_query_set_state(q, state);
+}