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Diffstat (limited to 'src/resolve/resolved-dns-query.c')
-rw-r--r--src/resolve/resolved-dns-query.c614
1 files changed, 459 insertions, 155 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index f7cb84e2a6..a96cf439ad 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -30,29 +30,286 @@
#define CNAME_MAX 8
#define QUERIES_MAX 2048
+#define AUXILIARY_QUERIES_MAX 64
-static void dns_query_stop(DnsQuery *q) {
- DnsTransaction *t;
+static int dns_query_candidate_new(DnsQueryCandidate **ret, DnsQuery *q, DnsScope *s) {
+ DnsQueryCandidate *c;
+ assert(ret);
assert(q);
+ assert(s);
- q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+ 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;
+}
- while ((t = set_steal_first(q->transactions))) {
- set_remove(t->queries, q);
+static void dns_query_candidate_stop(DnsQueryCandidate *c) {
+ DnsTransaction *t;
+
+ assert(c);
+
+ while ((t = set_steal_first(c->transactions))) {
+ set_remove(t->query_candidates, 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);
+
+ free(c);
+
+ return NULL;
+}
+
+static int dns_query_candidate_next_search_domain(DnsQueryCandidate *c) {
+ _cleanup_(dns_search_domain_unrefp) DnsSearchDomain *previous = NULL;
+ DnsSearchDomain *next = NULL;
+
+ assert(c);
+
+ if (c->search_domain && c->search_domain->linked) {
+ next = c->search_domain->domains_next;
+
+ if (!next) /* We hit the end of the list */
+ return 0;
+
+ } else {
+ next = dns_scope_get_search_domains(c->scope);
+
+ if (!next) /* OK, there's nothing. */
+ return 0;
+ }
+
+ 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);
+
+ r = set_ensure_allocated(&c->transactions, NULL);
+ if (r < 0)
+ return r;
+
+ t = dns_scope_find_transaction(c->scope, key, true);
+ if (!t) {
+ r = dns_transaction_new(&t, c->scope, key);
+ if (r < 0)
+ return r;
+ }
+
+ r = set_ensure_allocated(&t->query_candidates, NULL);
+ if (r < 0)
+ goto gc;
+
+ r = set_put(t->query_candidates, c);
+ if (r < 0)
+ goto gc;
+
+ r = set_put(c->transactions, t);
+ if (r < 0) {
+ set_remove(t->query_candidates, c);
+ goto gc;
+ }
+
+ return 0;
+
+gc:
+ dns_transaction_gc(t);
+ return r;
+}
+
+static int dns_query_candidate_go(DnsQueryCandidate *c) {
+ DnsTransaction *t;
+ Iterator i;
+ int r;
+
+ 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;
+ }
+
+ 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_RESOURCES;
+
+ SET_FOREACH(t, c->transactions, i) {
+
+ switch (t->state) {
+
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_NULL:
+ return t->state;
+
+ case DNS_TRANSACTION_SUCCESS:
+ state = t->state;
+ break;
+
+ default:
+ if (state != DNS_TRANSACTION_SUCCESS)
+ state = t->state;
+
+ break;
+ }
+ }
+
+ return state;
+}
+
+static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) {
+ DnsResourceKey *key;
+ int n = 0, r;
+
+ assert(c);
+
+ dns_query_candidate_stop(c);
+
+ /* Create one transaction per question key */
+ DNS_QUESTION_FOREACH(key, c->query->question) {
+ _cleanup_(dns_resource_key_unrefp) DnsResourceKey *new_key = NULL;
+
+ if (c->search_domain) {
+ r = dns_resource_key_new_append_suffix(&new_key, key, c->search_domain->name);
+ if (r < 0)
+ goto fail;
+ }
+
+ r = dns_query_candidate_add_transaction(c, new_key ?: key);
+ if (r < 0)
+ goto fail;
+
+ n++;
+ }
+
+ return n;
+
+fail:
+ dns_query_candidate_stop(c);
+ return r;
+}
+
+void dns_query_candidate_ready(DnsQueryCandidate *c) {
+ DnsTransactionState state;
+ int r;
+
+ assert(c);
+
+ state = dns_query_candidate_state(c);
+
+ if (IN_SET(state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_NULL))
+ 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);
+}
+
DnsQuery *dns_query_free(DnsQuery *q) {
if (!q)
return NULL;
- dns_query_stop(q);
- set_free(q->transactions);
+ 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);
+ }
+
+ while (q->candidates)
+ dns_query_candidate_free(q->candidates);
dns_question_unref(q->question);
dns_answer_unref(q->answer);
+ dns_search_domain_unref(q->answer_search_domain);
sd_bus_message_unref(q->request);
sd_bus_track_unref(q->bus_track);
@@ -75,7 +332,7 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex
assert(m);
assert(question);
- r = dns_question_is_valid(question);
+ r = dns_question_is_valid_for_query(question);
if (r < 0)
return r;
@@ -89,6 +346,8 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex
q->question = dns_question_ref(question);
q->ifindex = ifindex;
q->flags = flags;
+ q->answer_family = AF_UNSPEC;
+ q->answer_protocol = _DNS_PROTOCOL_INVALID;
for (i = 0; i < question->n_keys; i++) {
_cleanup_free_ char *p;
@@ -111,6 +370,29 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex
return 0;
}
+int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for) {
+ assert(q);
+ assert(auxiliary_for);
+
+ /* Ensure that 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(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
@@ -137,64 +419,40 @@ static int on_query_timeout(sd_event_source *s, usec_t usec, void *userdata) {
return 0;
}
-static int dns_query_add_transaction(DnsQuery *q, DnsScope *s, DnsResourceKey *key) {
- DnsTransaction *t;
+static int dns_query_add_candidate(DnsQuery *q, DnsScope *s) {
+ DnsQueryCandidate *c;
int r;
assert(q);
assert(s);
- assert(key);
- r = set_ensure_allocated(&q->transactions, NULL);
+ r = dns_query_candidate_new(&c, q, s);
if (r < 0)
return r;
- t = dns_scope_find_transaction(s, key, true);
- if (!t) {
- r = dns_transaction_new(&t, s, key);
- if (r < 0)
- return r;
- }
-
- r = set_ensure_allocated(&t->queries, NULL);
+ /* If this a single-label domain on DNS, we might append a suitable search domain first. */
+ r = dns_scope_name_needs_search_domain(s, dns_question_first_name(q->question));
if (r < 0)
- goto gc;
-
- r = set_put(t->queries, q);
- if (r < 0)
- goto gc;
+ goto fail;
+ if (r > 0) {
+ /* OK, we need a search domain now. Let's find one for this scope */
- r = set_put(q->transactions, t);
- if (r < 0) {
- set_remove(t->queries, q);
- goto gc;
+ 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;
-gc:
- dns_transaction_gc(t);
+fail:
+ dns_query_candidate_free(c);
return r;
}
-static int dns_query_add_transaction_split(DnsQuery *q, DnsScope *s) {
- unsigned i;
- int r;
-
- assert(q);
- assert(s);
-
- /* Create one transaction per question key */
-
- 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 0;
-}
-
static int SYNTHESIZE_IFINDEX(int ifindex) {
/* When the caller asked for resolving on a specific
@@ -597,9 +855,9 @@ static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
q->answer = answer;
answer = NULL;
- q->answer_family = SYNTHESIZE_FAMILY(q->flags);
- q->answer_protocol = SYNTHESIZE_PROTOCOL(q->flags);
q->answer_rcode = DNS_RCODE_SUCCESS;
+ q->answer_protocol = SYNTHESIZE_PROTOCOL(q->flags);
+ q->answer_family = SYNTHESIZE_FAMILY(q->flags);
*state = DNS_TRANSACTION_SUCCESS;
@@ -609,9 +867,8 @@ static int dns_query_synthesize_reply(DnsQuery *q, DnsTransactionState *state) {
int dns_query_go(DnsQuery *q) {
DnsScopeMatch found = DNS_SCOPE_NO;
DnsScope *s, *first = NULL;
- DnsTransaction *t;
+ DnsQueryCandidate *c;
const char *name;
- Iterator i;
int r;
assert(q);
@@ -622,7 +879,7 @@ int dns_query_go(DnsQuery *q) {
assert(q->question);
assert(q->question->n_keys > 0);
- name = DNS_RESOURCE_KEY_NAME(q->question->keys[0]);
+ name = dns_question_first_name(q->question);
LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
DnsScopeMatch match;
@@ -655,7 +912,7 @@ int dns_query_go(DnsQuery *q) {
return 1;
}
- r = dns_query_add_transaction_split(q, first);
+ r = dns_query_add_candidate(q, first);
if (r < 0)
goto fail;
@@ -669,7 +926,7 @@ int dns_query_go(DnsQuery *q) {
if (match != found)
continue;
- r = dns_query_add_transaction_split(q, s);
+ r = dns_query_add_candidate(q, s);
if (r < 0)
goto fail;
}
@@ -691,14 +948,13 @@ int dns_query_go(DnsQuery *q) {
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)
+ /* 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--;
@@ -711,132 +967,128 @@ fail:
return r;
}
-void dns_query_ready(DnsQuery *q) {
- DnsTransaction *t;
+static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- int rcode = 0;
- DnsScope *scope = NULL;
- bool pending = false;
+ DnsTransaction *t;
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->block_ready > 0)
+ if (!c) {
+ dns_query_synthesize_reply(q, &state);
+ dns_query_complete(q, state);
return;
+ }
- SET_FOREACH(t, q->transactions, i) {
+ SET_FOREACH(t, c->transactions, i) {
- /* If we found a successful answer, ignore all answers from other scopes */
- if (state == DNS_TRANSACTION_SUCCESS && t->scope != scope)
- continue;
+ switch (t->state) {
- /* 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;
- }
+ case DNS_TRANSACTION_SUCCESS: {
+ /* We found a successfuly reply, merge it into the answer */
+ DnsAnswer *merged;
- /* 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;
+ merged = dns_answer_merge(q->answer, t->answer);
+ if (!merged) {
+ dns_query_complete(q, DNS_TRANSACTION_RESOURCES);
+ return;
}
- if (state == DNS_TRANSACTION_SUCCESS) {
- DnsAnswer *merged;
+ dns_answer_unref(q->answer);
+ q->answer = merged;
+ q->answer_rcode = t->answer_rcode;
+
+ state = DNS_TRANSACTION_SUCCESS;
+ break;
+ }
+
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_NULL:
+ 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. */
- merged = dns_answer_merge(answer, a);
- if (!merged) {
- dns_query_complete(q, DNS_TRANSACTION_RESOURCES);
- return;
- }
+ if (state != DNS_TRANSACTION_SUCCESS) {
- dns_answer_unref(answer);
- answer = merged;
- } else {
- dns_answer_unref(answer);
- answer = dns_answer_ref(a);
+ dns_answer_unref(q->answer);
+ q->answer = dns_answer_ref(t->answer);
+ q->answer_rcode = t->answer_rcode;
+
+ state = t->state;
}
- scope = t->scope;
- state = DNS_TRANSACTION_SUCCESS;
- continue;
+ break;
}
+ }
- /* 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;
- }
+ q->answer_protocol = c->scope->protocol;
+ q->answer_family = c->scope->family;
- dns_answer_unref(answer);
- answer = dns_answer_ref(a);
+ dns_search_domain_unref(q->answer_search_domain);
+ q->answer_search_domain = dns_search_domain_ref(c->search_domain);
- scope = t->scope;
- state = DNS_TRANSACTION_FAILURE;
- continue;
- }
+ dns_query_synthesize_reply(q, &state);
+ dns_query_complete(q, state);
+}
- if (state == DNS_TRANSACTION_NO_SERVERS && t->state != DNS_TRANSACTION_NO_SERVERS)
- state = t->state;
- }
+void dns_query_ready(DnsQuery *q) {
+
+ DnsQueryCandidate *bad = NULL, *c;
+ bool pending = false;
- if (pending) {
+ assert(q);
+ assert(IN_SET(q->state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
- /* If so far we weren't successful, and there's
- * something still pending, then wait for it */
- if (state != DNS_TRANSACTION_SUCCESS)
+ /* 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 transactions is successful,
+ * let's use it, and copy its data out */
+ dns_query_accept(q, c);
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;
- }
- }
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_NULL:
+ /* One of the transactions is still going on, let's maybe wait for it */
+ pending = true;
+ break;
- if (IN_SET(state, DNS_TRANSACTION_SUCCESS, DNS_TRANSACTION_FAILURE)) {
- q->answer = dns_answer_ref(answer);
- q->answer_rcode = rcode;
- q->answer_protocol = scope ? scope->protocol : _DNS_PROTOCOL_INVALID;
- q->answer_family = scope ? scope->family : AF_UNSPEC;
+ default:
+ /* Any kind of failure */
+ bad = c;
+ break;
+ }
}
- /* Try to synthesize a reply if we couldn't resolve something. */
- dns_query_synthesize_reply(q, &state);
+ if (pending)
+ return;
- dns_query_complete(q, state);
+ dns_query_accept(q, bad);
}
-int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
+static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
_cleanup_(dns_question_unrefp) DnsQuestion *nq = NULL;
int r;
assert(q);
+ q->n_cname_redirects ++;
if (q->n_cname_redirects > CNAME_MAX)
return -ELOOP;
@@ -848,14 +1100,66 @@ int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
q->question = nq;
nq = NULL;
- q->n_cname_redirects++;
-
dns_query_stop(q);
q->state = DNS_TRANSACTION_NULL;
return 0;
}
+int dns_query_process_cname(DnsQuery *q) {
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL;
+ DnsResourceRecord *rr;
+ int r;
+
+ assert(q);
+
+ if (q->state != DNS_TRANSACTION_SUCCESS)
+ return 0;
+
+ DNS_ANSWER_FOREACH(rr, q->answer) {
+
+ r = dns_question_matches_rr(q->question, rr, DNS_SEARCH_DOMAIN_NAME(q->answer_search_domain));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return 0; /* The answer matches directly, no need to follow cnames */
+
+ r = dns_question_matches_cname(q->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 0; /* No cname to follow */
+
+ if (q->flags & SD_RESOLVED_NO_CNAME)
+ return -ELOOP;
+
+ /* 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 */
+ DNS_ANSWER_FOREACH(rr, q->answer) {
+ r = dns_question_matches_rr(q->question, rr, NULL);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return 0; /* It can answer it, yay! */
+ }
+
+ /* OK, it cannot, let's begin with the new query */
+ r = dns_query_go(q);
+ if (r < 0)
+ return r;
+
+ return 1; /* We return > 0, if we restarted the query for a new cname */
+}
+
static int on_bus_track(sd_bus_track *t, void *userdata) {
DnsQuery *q = userdata;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-01 11:40:49 +0000