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-rw-r--r--src/resolve/resolved-dns-query.c1109
1 files changed, 1109 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
new file mode 100644
index 0000000..535ef4e
--- /dev/null
+++ b/src/resolve/resolved-dns-query.c
@@ -0,0 +1,1109 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "alloc-util.h"
+#include "dns-domain.h"
+#include "dns-type.h"
+#include "hostname-util.h"
+#include "local-addresses.h"
+#include "resolved-dns-query.h"
+#include "resolved-dns-synthesize.h"
+#include "resolved-etc-hosts.h"
+#include "string-util.h"
+
+#define CNAME_MAX 8
+#define QUERIES_MAX 2048
+#define AUXILIARY_QUERIES_MAX 64
+
+static int dns_query_candidate_new(DnsQueryCandidate **ret, DnsQuery *q, DnsScope *s) {
+ DnsQueryCandidate *c;
+
+ assert(ret);
+ assert(q);
+ assert(s);
+
+ c = new0(DnsQueryCandidate, 1);
+ if (!c)
+ return -ENOMEM;
+
+ c->query = q;
+ c->scope = s;
+
+ LIST_PREPEND(candidates_by_query, q->candidates, c);
+ LIST_PREPEND(candidates_by_scope, s->query_candidates, c);
+
+ *ret = c;
+ return 0;
+}
+
+static void dns_query_candidate_stop(DnsQueryCandidate *c) {
+ DnsTransaction *t;
+
+ assert(c);
+
+ while ((t = set_steal_first(c->transactions))) {
+ set_remove(t->notify_query_candidates, c);
+ set_remove(t->notify_query_candidates_done, c);
+ dns_transaction_gc(t);
+ }
+}
+
+DnsQueryCandidate* dns_query_candidate_free(DnsQueryCandidate *c) {
+
+ if (!c)
+ return NULL;
+
+ dns_query_candidate_stop(c);
+
+ set_free(c->transactions);
+ dns_search_domain_unref(c->search_domain);
+
+ if (c->query)
+ LIST_REMOVE(candidates_by_query, c->query->candidates, c);
+
+ if (c->scope)
+ LIST_REMOVE(candidates_by_scope, c->scope->query_candidates, c);
+
+ return mfree(c);
+}
+
+static int dns_query_candidate_next_search_domain(DnsQueryCandidate *c) {
+ DnsSearchDomain *next = NULL;
+
+ assert(c);
+
+ if (c->search_domain && c->search_domain->linked)
+ next = c->search_domain->domains_next;
+ else
+ next = dns_scope_get_search_domains(c->scope);
+
+ for (;;) {
+ if (!next) /* We hit the end of the list */
+ return 0;
+
+ if (!next->route_only)
+ break;
+
+ /* Skip over route-only domains */
+ next = next->domains_next;
+ }
+
+ dns_search_domain_unref(c->search_domain);
+ c->search_domain = dns_search_domain_ref(next);
+
+ return 1;
+}
+
+static int dns_query_candidate_add_transaction(DnsQueryCandidate *c, DnsResourceKey *key) {
+ DnsTransaction *t;
+ int r;
+
+ assert(c);
+ assert(key);
+
+ t = dns_scope_find_transaction(c->scope, key, true);
+ if (!t) {
+ r = dns_transaction_new(&t, c->scope, key);
+ if (r < 0)
+ return r;
+ } else {
+ if (set_contains(c->transactions, t))
+ return 0;
+ }
+
+ r = set_ensure_allocated(&c->transactions, NULL);
+ if (r < 0)
+ goto gc;
+
+ r = set_ensure_allocated(&t->notify_query_candidates, NULL);
+ if (r < 0)
+ goto gc;
+
+ r = set_ensure_allocated(&t->notify_query_candidates_done, NULL);
+ if (r < 0)
+ goto gc;
+
+ r = set_put(t->notify_query_candidates, c);
+ if (r < 0)
+ goto gc;
+
+ r = set_put(c->transactions, t);
+ if (r < 0) {
+ (void) set_remove(t->notify_query_candidates, c);
+ goto gc;
+ }
+
+ t->clamp_ttl = c->query->clamp_ttl;
+ return 1;
+
+gc:
+ dns_transaction_gc(t);
+ return r;
+}
+
+static int dns_query_candidate_go(DnsQueryCandidate *c) {
+ DnsTransaction *t;
+ Iterator i;
+ int r;
+ unsigned n = 0;
+
+ assert(c);
+
+ /* Start the transactions that are not started yet */
+ SET_FOREACH(t, c->transactions, i) {
+ if (t->state != DNS_TRANSACTION_NULL)
+ continue;
+
+ r = dns_transaction_go(t);
+ if (r < 0)
+ return r;
+
+ n++;
+ }
+
+ /* If there was nothing to start, then let's proceed immediately */
+ if (n == 0)
+ dns_query_candidate_notify(c);
+
+ return 0;
+}
+
+static DnsTransactionState dns_query_candidate_state(DnsQueryCandidate *c) {
+ DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
+ DnsTransaction *t;
+ Iterator i;
+
+ assert(c);
+
+ if (c->error_code != 0)
+ return DNS_TRANSACTION_ERRNO;
+
+ SET_FOREACH(t, c->transactions, i) {
+
+ switch (t->state) {
+
+ case DNS_TRANSACTION_NULL:
+ /* If there's a NULL transaction pending, then
+ * this means not all transactions where
+ * started yet, and we were called from within
+ * the stackframe that is supposed to start
+ * remaining transactions. In this case,
+ * simply claim the candidate is pending. */
+
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_VALIDATING:
+ /* If there's one transaction currently in
+ * VALIDATING state, then this means there's
+ * also one in PENDING state, hence we can
+ * return PENDING immediately. */
+ return DNS_TRANSACTION_PENDING;
+
+ case DNS_TRANSACTION_SUCCESS:
+ state = t->state;
+ break;
+
+ default:
+ if (state != DNS_TRANSACTION_SUCCESS)
+ state = t->state;
+
+ break;
+ }
+ }
+
+ return state;
+}
+
+static bool dns_query_candidate_is_routable(DnsQueryCandidate *c, uint16_t type) {
+ int family;
+
+ assert(c);
+
+ /* Checks whether the specified RR type matches an address family that is routable on the link(s) the scope of
+ * this candidate belongs to. Specifically, whether there's a routable IPv4 address on it if we query an A RR,
+ * or a routable IPv6 address if we query an AAAA RR. */
+
+ if (!c->query->suppress_unroutable_family)
+ return true;
+
+ if (c->scope->protocol != DNS_PROTOCOL_DNS)
+ return true;
+
+ family = dns_type_to_af(type);
+ if (family < 0)
+ return true;
+
+ if (c->scope->link)
+ return link_relevant(c->scope->link, family, false);
+ else
+ return manager_routable(c->scope->manager, family);
+}
+
+static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) {
+ DnsQuestion *question;
+ DnsResourceKey *key;
+ int n = 0, r;
+
+ assert(c);
+
+ dns_query_candidate_stop(c);
+
+ question = dns_query_question_for_protocol(c->query, c->scope->protocol);
+
+ /* Create one transaction per question key */
+ DNS_QUESTION_FOREACH(key, question) {
+ _cleanup_(dns_resource_key_unrefp) DnsResourceKey *new_key = NULL;
+ DnsResourceKey *qkey;
+
+ if (!dns_query_candidate_is_routable(c, key->type))
+ continue;
+
+ if (c->search_domain) {
+ r = dns_resource_key_new_append_suffix(&new_key, key, c->search_domain->name);
+ if (r < 0)
+ goto fail;
+
+ qkey = new_key;
+ } else
+ qkey = key;
+
+ if (!dns_scope_good_key(c->scope, qkey))
+ continue;
+
+ r = dns_query_candidate_add_transaction(c, qkey);
+ if (r < 0)
+ goto fail;
+
+ n++;
+ }
+
+ return n;
+
+fail:
+ dns_query_candidate_stop(c);
+ return r;
+}
+
+void dns_query_candidate_notify(DnsQueryCandidate *c) {
+ DnsTransactionState state;
+ int r;
+
+ assert(c);
+
+ state = dns_query_candidate_state(c);
+
+ if (DNS_TRANSACTION_IS_LIVE(state))
+ return;
+
+ if (state != DNS_TRANSACTION_SUCCESS && c->search_domain) {
+
+ r = dns_query_candidate_next_search_domain(c);
+ if (r < 0)
+ goto fail;
+
+ if (r > 0) {
+ /* OK, there's another search domain to try, let's do so. */
+
+ r = dns_query_candidate_setup_transactions(c);
+ if (r < 0)
+ goto fail;
+
+ if (r > 0) {
+ /* New transactions where queued. Start them and wait */
+
+ r = dns_query_candidate_go(c);
+ if (r < 0)
+ goto fail;
+
+ return;
+ }
+ }
+
+ }
+
+ dns_query_ready(c->query);
+ return;
+
+fail:
+ log_warning_errno(r, "Failed to follow search domains: %m");
+ c->error_code = r;
+ dns_query_ready(c->query);
+}
+
+static void dns_query_stop(DnsQuery *q) {
+ DnsQueryCandidate *c;
+
+ assert(q);
+
+ q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+
+ LIST_FOREACH(candidates_by_query, c, q->candidates)
+ dns_query_candidate_stop(c);
+}
+
+static void dns_query_free_candidates(DnsQuery *q) {
+ assert(q);
+
+ while (q->candidates)
+ dns_query_candidate_free(q->candidates);
+}
+
+static void dns_query_reset_answer(DnsQuery *q) {
+ assert(q);
+
+ q->answer = dns_answer_unref(q->answer);
+ q->answer_rcode = 0;
+ q->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
+ q->answer_errno = 0;
+ q->answer_authenticated = false;
+ q->answer_protocol = _DNS_PROTOCOL_INVALID;
+ q->answer_family = AF_UNSPEC;
+ q->answer_search_domain = dns_search_domain_unref(q->answer_search_domain);
+}
+
+DnsQuery *dns_query_free(DnsQuery *q) {
+ if (!q)
+ return NULL;
+
+ while (q->auxiliary_queries)
+ dns_query_free(q->auxiliary_queries);
+
+ if (q->auxiliary_for) {
+ assert(q->auxiliary_for->n_auxiliary_queries > 0);
+ q->auxiliary_for->n_auxiliary_queries--;
+ LIST_REMOVE(auxiliary_queries, q->auxiliary_for->auxiliary_queries, q);
+ }
+
+ dns_query_free_candidates(q);
+
+ dns_question_unref(q->question_idna);
+ dns_question_unref(q->question_utf8);
+
+ dns_query_reset_answer(q);
+
+ sd_bus_message_unref(q->request);
+ sd_bus_track_unref(q->bus_track);
+
+ dns_packet_unref(q->request_dns_packet);
+ dns_packet_unref(q->reply_dns_packet);
+
+ if (q->request_dns_stream) {
+ /* Detach the stream from our query, in case something else keeps a reference to it. */
+ q->request_dns_stream->complete = NULL;
+ q->request_dns_stream->on_packet = NULL;
+ q->request_dns_stream->query = NULL;
+ dns_stream_unref(q->request_dns_stream);
+ }
+
+ free(q->request_address_string);
+
+ if (q->manager) {
+ LIST_REMOVE(queries, q->manager->dns_queries, q);
+ q->manager->n_dns_queries--;
+ }
+
+ return mfree(q);
+}
+
+int dns_query_new(
+ Manager *m,
+ DnsQuery **ret,
+ DnsQuestion *question_utf8,
+ DnsQuestion *question_idna,
+ int ifindex,
+ uint64_t flags) {
+
+ _cleanup_(dns_query_freep) DnsQuery *q = NULL;
+ DnsResourceKey *key;
+ bool good = false;
+ int r;
+ char key_str[DNS_RESOURCE_KEY_STRING_MAX];
+
+ assert(m);
+
+ if (dns_question_size(question_utf8) > 0) {
+ r = dns_question_is_valid_for_query(question_utf8);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EINVAL;
+
+ good = true;
+ }
+
+ /* If the IDNA and UTF8 questions are the same, merge their references */
+ r = dns_question_is_equal(question_idna, question_utf8);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ question_idna = question_utf8;
+ else {
+ if (dns_question_size(question_idna) > 0) {
+ r = dns_question_is_valid_for_query(question_idna);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EINVAL;
+
+ good = true;
+ }
+ }
+
+ if (!good) /* don't allow empty queries */
+ return -EINVAL;
+
+ if (m->n_dns_queries >= QUERIES_MAX)
+ return -EBUSY;
+
+ q = new0(DnsQuery, 1);
+ if (!q)
+ return -ENOMEM;
+
+ q->question_utf8 = dns_question_ref(question_utf8);
+ q->question_idna = dns_question_ref(question_idna);
+ q->ifindex = ifindex;
+ q->flags = flags;
+ q->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
+ q->answer_protocol = _DNS_PROTOCOL_INVALID;
+ q->answer_family = AF_UNSPEC;
+
+ /* First dump UTF8 question */
+ DNS_QUESTION_FOREACH(key, question_utf8)
+ log_debug("Looking up RR for %s.",
+ dns_resource_key_to_string(key, key_str, sizeof key_str));
+
+ /* And then dump the IDNA question, but only what hasn't been dumped already through the UTF8 question. */
+ DNS_QUESTION_FOREACH(key, question_idna) {
+ r = dns_question_contains(question_utf8, key);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ continue;
+
+ log_debug("Looking up IDNA RR for %s.",
+ dns_resource_key_to_string(key, key_str, sizeof key_str));
+ }
+
+ LIST_PREPEND(queries, m->dns_queries, q);
+ m->n_dns_queries++;
+ q->manager = m;
+
+ if (ret)
+ *ret = q;
+ q = NULL;
+
+ return 0;
+}
+
+int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for) {
+ assert(q);
+ assert(auxiliary_for);
+
+ /* Ensure that the query is not auxiliary yet, and
+ * nothing else is auxiliary to it either */
+ assert(!q->auxiliary_for);
+ assert(!q->auxiliary_queries);
+
+ /* Ensure that the unit we shall be made auxiliary for isn't
+ * auxiliary itself */
+ assert(!auxiliary_for->auxiliary_for);
+
+ if (auxiliary_for->n_auxiliary_queries >= AUXILIARY_QUERIES_MAX)
+ return -EAGAIN;
+
+ LIST_PREPEND(auxiliary_queries, auxiliary_for->auxiliary_queries, q);
+ q->auxiliary_for = auxiliary_for;
+
+ auxiliary_for->n_auxiliary_queries++;
+ return 0;
+}
+
+static void dns_query_complete(DnsQuery *q, DnsTransactionState state) {
+ assert(q);
+ assert(!DNS_TRANSACTION_IS_LIVE(state));
+ assert(DNS_TRANSACTION_IS_LIVE(q->state));
+
+ /* Note that this call might invalidate the query. Callers
+ * should hence not attempt to access the query or transaction
+ * after calling this function. */
+
+ q->state = state;
+
+ dns_query_stop(q);
+ 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_complete(q, DNS_TRANSACTION_TIMEOUT);
+ return 0;
+}
+
+static int dns_query_add_candidate(DnsQuery *q, DnsScope *s) {
+ DnsQueryCandidate *c;
+ int r;
+
+ assert(q);
+ assert(s);
+
+ r = dns_query_candidate_new(&c, q, s);
+ if (r < 0)
+ return r;
+
+ /* If this a single-label domain on DNS, we might append a suitable search domain first. */
+ if ((q->flags & SD_RESOLVED_NO_SEARCH) == 0 &&
+ dns_scope_name_needs_search_domain(s, dns_question_first_name(q->question_idna))) {
+ /* OK, we need a search domain now. Let's find one for this scope */
+
+ r = dns_query_candidate_next_search_domain(c);
+ if (r <= 0) /* if there's no search domain, then we won't add any transaction. */
+ goto fail;
+ }
+
+ r = dns_query_candidate_setup_transactions(c);
+ if (r < 0)
+ goto fail;
+
+ return 0;
+
+fail:
+ dns_query_candidate_free(c);
+ return r;
+}
+
+static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ int r;
+
+ assert(q);
+ assert(state);
+
+ /* Tries to synthesize localhost RR replies (and others) where appropriate. Note that this is done *after* the
+ * the normal lookup finished. The data from the network hence takes precedence over the data we
+ * synthesize. (But note that many scopes refuse to resolve certain domain names) */
+
+ if (!IN_SET(*state,
+ DNS_TRANSACTION_RCODE_FAILURE,
+ DNS_TRANSACTION_NO_SERVERS,
+ DNS_TRANSACTION_TIMEOUT,
+ DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
+ DNS_TRANSACTION_NETWORK_DOWN,
+ DNS_TRANSACTION_NOT_FOUND))
+ return 0;
+
+ r = dns_synthesize_answer(
+ q->manager,
+ q->question_utf8,
+ q->ifindex,
+ &answer);
+ if (r == -ENXIO) {
+ /* If we get ENXIO this tells us to generate NXDOMAIN unconditionally. */
+
+ dns_query_reset_answer(q);
+ q->answer_rcode = DNS_RCODE_NXDOMAIN;
+ q->answer_protocol = dns_synthesize_protocol(q->flags);
+ q->answer_family = dns_synthesize_family(q->flags);
+ q->answer_authenticated = true;
+ *state = DNS_TRANSACTION_RCODE_FAILURE;
+
+ return 0;
+ }
+ if (r <= 0)
+ return r;
+
+ dns_query_reset_answer(q);
+
+ q->answer = TAKE_PTR(answer);
+ q->answer_rcode = DNS_RCODE_SUCCESS;
+ q->answer_protocol = dns_synthesize_protocol(q->flags);
+ q->answer_family = dns_synthesize_family(q->flags);
+ q->answer_authenticated = true;
+
+ *state = DNS_TRANSACTION_SUCCESS;
+
+ return 1;
+}
+
+static int dns_query_try_etc_hosts(DnsQuery *q) {
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ int r;
+
+ assert(q);
+
+ /* Looks in /etc/hosts for matching entries. Note that this is done *before* the normal lookup is done. The
+ * data from /etc/hosts hence takes precedence over the network. */
+
+ r = manager_etc_hosts_lookup(
+ q->manager,
+ q->question_utf8,
+ &answer);
+ if (r <= 0)
+ return r;
+
+ dns_query_reset_answer(q);
+
+ q->answer = TAKE_PTR(answer);
+ q->answer_rcode = DNS_RCODE_SUCCESS;
+ q->answer_protocol = dns_synthesize_protocol(q->flags);
+ q->answer_family = dns_synthesize_family(q->flags);
+ q->answer_authenticated = true;
+
+ return 1;
+}
+
+int dns_query_go(DnsQuery *q) {
+ DnsScopeMatch found = DNS_SCOPE_NO;
+ DnsScope *s, *first = NULL;
+ DnsQueryCandidate *c;
+ int r;
+
+ assert(q);
+
+ if (q->state != DNS_TRANSACTION_NULL)
+ return 0;
+
+ r = dns_query_try_etc_hosts(q);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ dns_query_complete(q, DNS_TRANSACTION_SUCCESS);
+ return 1;
+ }
+
+ LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
+ DnsScopeMatch match;
+ const char *name;
+
+ name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol));
+ if (!name)
+ continue;
+
+ match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
+ if (match < 0) {
+ log_debug("Couldn't check if '%s' matches against scope, ignoring.", name);
+ continue;
+ }
+
+ if (match > found) { /* Does this match better? If so, remember how well it matched, and the first one
+ * that matches this well */
+ found = match;
+ first = s;
+ }
+ }
+
+ if (found == DNS_SCOPE_NO) {
+ DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
+
+ r = dns_query_synthesize_reply(q, &state);
+ if (r < 0)
+ return r;
+
+ dns_query_complete(q, state);
+ return 1;
+ }
+
+ r = dns_query_add_candidate(q, first);
+ if (r < 0)
+ goto fail;
+
+ LIST_FOREACH(scopes, s, first->scopes_next) {
+ DnsScopeMatch match;
+ const char *name;
+
+ name = dns_question_first_name(dns_query_question_for_protocol(q, s->protocol));
+ if (!name)
+ continue;
+
+ match = dns_scope_good_domain(s, q->ifindex, q->flags, name);
+ if (match < 0) {
+ log_debug("Couldn't check if '%s' matches against scope, ignoring.", name);
+ continue;
+ }
+
+ if (match < found)
+ continue;
+
+ r = dns_query_add_candidate(q, s);
+ if (r < 0)
+ goto fail;
+ }
+
+ dns_query_reset_answer(q);
+
+ r = sd_event_add_time(
+ q->manager->event,
+ &q->timeout_event_source,
+ clock_boottime_or_monotonic(),
+ now(clock_boottime_or_monotonic()) + SD_RESOLVED_QUERY_TIMEOUT_USEC,
+ 0, on_query_timeout, q);
+ if (r < 0)
+ goto fail;
+
+ (void) sd_event_source_set_description(q->timeout_event_source, "query-timeout");
+
+ q->state = DNS_TRANSACTION_PENDING;
+ q->block_ready++;
+
+ /* Start the transactions */
+ LIST_FOREACH(candidates_by_query, c, q->candidates) {
+ r = dns_query_candidate_go(c);
+ if (r < 0) {
+ q->block_ready--;
+ goto fail;
+ }
+ }
+
+ q->block_ready--;
+ dns_query_ready(q);
+
+ return 1;
+
+fail:
+ dns_query_stop(q);
+ return r;
+}
+
+static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
+ DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
+ bool has_authenticated = false, has_non_authenticated = false;
+ DnssecResult dnssec_result_authenticated = _DNSSEC_RESULT_INVALID, dnssec_result_non_authenticated = _DNSSEC_RESULT_INVALID;
+ DnsTransaction *t;
+ Iterator i;
+ int r;
+
+ assert(q);
+
+ if (!c) {
+ r = dns_query_synthesize_reply(q, &state);
+ if (r < 0)
+ goto fail;
+
+ dns_query_complete(q, state);
+ return;
+ }
+
+ if (c->error_code != 0) {
+ /* If the candidate had an error condition of its own, start with that. */
+ state = DNS_TRANSACTION_ERRNO;
+ q->answer = dns_answer_unref(q->answer);
+ q->answer_rcode = 0;
+ q->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
+ q->answer_authenticated = false;
+ q->answer_errno = c->error_code;
+ }
+
+ SET_FOREACH(t, c->transactions, i) {
+
+ switch (t->state) {
+
+ case DNS_TRANSACTION_SUCCESS: {
+ /* We found a successfully reply, merge it into the answer */
+ r = dns_answer_extend(&q->answer, t->answer);
+ if (r < 0)
+ goto fail;
+
+ q->answer_rcode = t->answer_rcode;
+ q->answer_errno = 0;
+
+ if (t->answer_authenticated) {
+ has_authenticated = true;
+ dnssec_result_authenticated = t->answer_dnssec_result;
+ } else {
+ has_non_authenticated = true;
+ dnssec_result_non_authenticated = t->answer_dnssec_result;
+ }
+
+ state = DNS_TRANSACTION_SUCCESS;
+ break;
+ }
+
+ case DNS_TRANSACTION_NULL:
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_VALIDATING:
+ case DNS_TRANSACTION_ABORTED:
+ /* Ignore transactions that didn't complete */
+ continue;
+
+ default:
+ /* Any kind of failure? Store the data away, if there's nothing stored yet. */
+ if (state == DNS_TRANSACTION_SUCCESS)
+ continue;
+
+ /* If there's already an authenticated negative reply stored, then prefer that over any unauthenticated one */
+ if (q->answer_authenticated && !t->answer_authenticated)
+ continue;
+
+ q->answer = dns_answer_unref(q->answer);
+ q->answer_rcode = t->answer_rcode;
+ q->answer_dnssec_result = t->answer_dnssec_result;
+ q->answer_authenticated = t->answer_authenticated;
+ q->answer_errno = t->answer_errno;
+
+ state = t->state;
+ break;
+ }
+ }
+
+ if (state == DNS_TRANSACTION_SUCCESS) {
+ q->answer_authenticated = has_authenticated && !has_non_authenticated;
+ q->answer_dnssec_result = q->answer_authenticated ? dnssec_result_authenticated : dnssec_result_non_authenticated;
+ }
+
+ q->answer_protocol = c->scope->protocol;
+ q->answer_family = c->scope->family;
+
+ dns_search_domain_unref(q->answer_search_domain);
+ q->answer_search_domain = dns_search_domain_ref(c->search_domain);
+
+ r = dns_query_synthesize_reply(q, &state);
+ if (r < 0)
+ goto fail;
+
+ dns_query_complete(q, state);
+ return;
+
+fail:
+ q->answer_errno = -r;
+ dns_query_complete(q, DNS_TRANSACTION_ERRNO);
+}
+
+void dns_query_ready(DnsQuery *q) {
+
+ DnsQueryCandidate *bad = NULL, *c;
+ bool pending = false;
+
+ assert(q);
+ assert(DNS_TRANSACTION_IS_LIVE(q->state));
+
+ /* 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->block_ready > 0)
+ return;
+
+ LIST_FOREACH(candidates_by_query, c, q->candidates) {
+ DnsTransactionState state;
+
+ state = dns_query_candidate_state(c);
+ switch (state) {
+
+ case DNS_TRANSACTION_SUCCESS:
+ /* One of the candidates is successful,
+ * let's use it, and copy its data out */
+ dns_query_accept(q, c);
+ return;
+
+ case DNS_TRANSACTION_NULL:
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_VALIDATING:
+ /* One of the candidates is still going on,
+ * let's maybe wait for it */
+ pending = true;
+ break;
+
+ default:
+ /* Any kind of failure */
+ bad = c;
+ break;
+ }
+ }
+
+ if (pending)
+ return;
+
+ dns_query_accept(q, bad);
+}
+
+static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
+ _cleanup_(dns_question_unrefp) DnsQuestion *nq_idna = NULL, *nq_utf8 = NULL;
+ int r, k;
+
+ assert(q);
+
+ q->n_cname_redirects++;
+ if (q->n_cname_redirects > CNAME_MAX)
+ return -ELOOP;
+
+ r = dns_question_cname_redirect(q->question_idna, cname, &nq_idna);
+ if (r < 0)
+ return r;
+ else if (r > 0)
+ log_debug("Following CNAME/DNAME %s → %s.", dns_question_first_name(q->question_idna), dns_question_first_name(nq_idna));
+
+ k = dns_question_is_equal(q->question_idna, q->question_utf8);
+ if (k < 0)
+ return r;
+ if (k > 0) {
+ /* Same question? Shortcut new question generation */
+ nq_utf8 = dns_question_ref(nq_idna);
+ k = r;
+ } else {
+ k = dns_question_cname_redirect(q->question_utf8, cname, &nq_utf8);
+ if (k < 0)
+ return k;
+ else if (k > 0)
+ log_debug("Following UTF8 CNAME/DNAME %s → %s.", dns_question_first_name(q->question_utf8), dns_question_first_name(nq_utf8));
+ }
+
+ if (r == 0 && k == 0) /* No actual cname happened? */
+ return -ELOOP;
+
+ if (q->answer_protocol == DNS_PROTOCOL_DNS) {
+ /* Don't permit CNAME redirects from unicast DNS to LLMNR or MulticastDNS, so that global resources
+ * cannot invade the local namespace. The opposite way we permit: local names may redirect to global
+ * ones. */
+
+ q->flags &= ~(SD_RESOLVED_LLMNR|SD_RESOLVED_MDNS); /* mask away the local protocols */
+ }
+
+ /* Turn off searching for the new name */
+ q->flags |= SD_RESOLVED_NO_SEARCH;
+
+ dns_question_unref(q->question_idna);
+ q->question_idna = TAKE_PTR(nq_idna);
+
+ dns_question_unref(q->question_utf8);
+ q->question_utf8 = TAKE_PTR(nq_utf8);
+
+ dns_query_free_candidates(q);
+ dns_query_reset_answer(q);
+
+ q->state = DNS_TRANSACTION_NULL;
+
+ return 0;
+}
+
+int dns_query_process_cname(DnsQuery *q) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL;
+ DnsQuestion *question;
+ DnsResourceRecord *rr;
+ int r;
+
+ assert(q);
+
+ if (!IN_SET(q->state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_NULL))
+ return DNS_QUERY_NOMATCH;
+
+ question = dns_query_question_for_protocol(q, q->answer_protocol);
+
+ DNS_ANSWER_FOREACH(rr, q->answer) {
+ r = dns_question_matches_rr(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return DNS_QUERY_MATCH; /* The answer matches directly, no need to follow cnames */
+
+ r = dns_question_matches_cname_or_dname(question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain));
+ if (r < 0)
+ return r;
+ if (r > 0 && !cname)
+ cname = dns_resource_record_ref(rr);
+ }
+
+ if (!cname)
+ return DNS_QUERY_NOMATCH; /* No match and no cname to follow */
+
+ if (q->flags & SD_RESOLVED_NO_CNAME)
+ return -ELOOP;
+
+ if (!q->answer_authenticated)
+ q->previous_redirect_unauthenticated = true;
+
+ /* OK, let's actually follow the CNAME */
+ r = dns_query_cname_redirect(q, cname);
+ if (r < 0)
+ return r;
+
+ /* Let's see if the answer can already answer the new
+ * redirected question */
+ r = dns_query_process_cname(q);
+ if (r != DNS_QUERY_NOMATCH)
+ return r;
+
+ /* OK, it cannot, let's begin with the new query */
+ r = dns_query_go(q);
+ if (r < 0)
+ return r;
+
+ return DNS_QUERY_RESTARTED; /* We restarted the query for a new cname */
+}
+
+static int on_bus_track(sd_bus_track *t, void *userdata) {
+ DnsQuery *q = userdata;
+
+ assert(t);
+ assert(q);
+
+ log_debug("Client of active query vanished, aborting query.");
+ dns_query_complete(q, DNS_TRANSACTION_ABORTED);
+ return 0;
+}
+
+int dns_query_bus_track(DnsQuery *q, sd_bus_message *m) {
+ int r;
+
+ assert(q);
+ assert(m);
+
+ if (!q->bus_track) {
+ r = sd_bus_track_new(sd_bus_message_get_bus(m), &q->bus_track, on_bus_track, q);
+ if (r < 0)
+ return r;
+ }
+
+ r = sd_bus_track_add_sender(q->bus_track, m);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+DnsQuestion* dns_query_question_for_protocol(DnsQuery *q, DnsProtocol protocol) {
+ assert(q);
+
+ switch (protocol) {
+
+ case DNS_PROTOCOL_DNS:
+ return q->question_idna;
+
+ case DNS_PROTOCOL_MDNS:
+ case DNS_PROTOCOL_LLMNR:
+ return q->question_utf8;
+
+ default:
+ return NULL;
+ }
+}
+
+const char *dns_query_string(DnsQuery *q) {
+ const char *name;
+ int r;
+
+ /* Returns a somewhat useful human-readable lookup key string for this query */
+
+ if (q->request_address_string)
+ return q->request_address_string;
+
+ if (q->request_address_valid) {
+ r = in_addr_to_string(q->request_family, &q->request_address, &q->request_address_string);
+ if (r >= 0)
+ return q->request_address_string;
+ }
+
+ name = dns_question_first_name(q->question_utf8);
+ if (name)
+ return name;
+
+ return dns_question_first_name(q->question_idna);
+}
+
+bool dns_query_fully_authenticated(DnsQuery *q) {
+ assert(q);
+
+ return q->answer_authenticated && !q->previous_redirect_unauthenticated;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 17:57:47 +0000