case DNS_TRANSACTION_RCODE_FAILURE:
if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) {
- log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode));
+ log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", FORMAT_DNS_RCODE(dt->answer_rcode));
goto fail;
}
log_debug("Processing incoming packet of size %zu on transaction %" PRIu16" (rcode=%s).",
p->size,
- t->id, dns_rcode_to_string(DNS_PACKET_RCODE(p)));
+ t->id, FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p)));
switch (t->scope->protocol) {
return;
/* Give up, accept the rcode */
- log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p)));
+ log_debug("Server returned error: %s", FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p)));
break;
}
t->clamp_feature_level_servfail < 0) {
t->clamp_feature_level_servfail = t->current_feature_level;
log_debug("Server returned error %s, retrying transaction.",
- dns_rcode_to_string(DNS_PACKET_RCODE(p)));
+ FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p)));
} else {
/* Reduce this feature level by one and try again. */
switch (t->current_feature_level) {
}
log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
- dns_rcode_to_string(DNS_PACKET_RCODE(p)),
+ FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p)),
dns_server_feature_level_to_string(t->clamp_feature_level_servfail));
}
t->clamp_feature_level_nxdomain = DNS_SERVER_FEATURE_LEVEL_UDP;
log_debug("Server returned error %s in EDNS0 mode, retrying transaction with reduced feature level %s (DVE-2018-0001 mitigation)",
- dns_rcode_to_string(DNS_PACKET_RCODE(p)),
+ FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p)),
dns_server_feature_level_to_string(t->clamp_feature_level_nxdomain));
dns_transaction_retry(t, false /* use the same server */);
return 0;
}
+ static int dns_transaction_setup_timeout(
+ DnsTransaction *t,
+ usec_t timeout_usec /* relative */,
+ usec_t next_usec /* CLOCK_BOOTTIME */) {
+
+ int r;
+
+ assert(t);
+
+ dns_transaction_stop_timeout(t);
+
+ r = sd_event_add_time_relative(
+ t->scope->manager->event,
+ &t->timeout_event_source,
+ CLOCK_BOOTTIME,
+ timeout_usec, 0,
+ on_transaction_timeout, t);
+ if (r < 0)
+ return r;
+
+ (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
+
+ t->next_attempt_after = next_usec;
+ t->state = DNS_TRANSACTION_PENDING;
+ return 0;
+ }
+
static usec_t transaction_get_resend_timeout(DnsTransaction *t) {
assert(t);
assert(t->scope);
return DNS_TIMEOUT_USEC;
case DNS_PROTOCOL_MDNS:
- assert(t->n_attempts > 0);
if (t->probing)
return MDNS_PROBING_INTERVAL_USEC;
- else
- return (1 << (t->n_attempts - 1)) * USEC_PER_SEC;
+
+ /* See RFC 6762 Section 5.1 suggests that timeout should be a few seconds. */
+ assert(t->n_attempts > 0);
+ return (1 << (t->n_attempts - 1)) * USEC_PER_SEC;
case DNS_PROTOCOL_LLMNR:
return t->scope->resend_timeout;
return 0;
}
- if (t->n_attempts >= dns_transaction_attempts_max(t->scope->protocol, t->probing)) {
+ if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) {
DnsTransactionState result;
if (t->scope->protocol == DNS_PROTOCOL_LLMNR)
return 1;
}
+ static int dns_packet_append_zone(DnsPacket *p, DnsTransaction *t, DnsResourceKey *k, unsigned *nscount) {
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ bool tentative;
+ int r;
+
+ assert(p);
+ assert(t);
+ assert(k);
+
+ if (k->type != DNS_TYPE_ANY)
+ return 0;
+
+ r = dns_zone_lookup(&t->scope->zone, k, t->scope->link->ifindex, &answer, NULL, &tentative);
+ if (r < 0)
+ return r;
+
+ return dns_packet_append_answer(p, answer, nscount);
+ }
+
static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
- bool add_known_answers = false;
- DnsResourceKey *tkey;
_cleanup_set_free_ Set *keys = NULL;
- unsigned qdcount;
- unsigned nscount = 0;
+ unsigned qdcount, ancount = 0 /* avoid false maybe-uninitialized warning */, nscount;
+ bool add_known_answers = false;
usec_t ts;
int r;
/* Discard any previously prepared packet, so we can start over and coalesce again */
t->sent = dns_packet_unref(t->sent);
+ /* First, create a dummy packet to calculate packet size. */
r = dns_packet_new_query(&p, t->scope->protocol, 0, false);
if (r < 0)
return r;
if (dns_key_is_shared(dns_transaction_key(t)))
add_known_answers = true;
- if (dns_transaction_key(t)->type == DNS_TYPE_ANY) {
- r = set_ensure_put(&keys, &dns_resource_key_hash_ops, dns_transaction_key(t));
- if (r < 0)
- return r;
- }
+ r = dns_packet_append_zone(p, t, dns_transaction_key(t), NULL);
+ if (r < 0)
+ return r;
+
+ /* Save appended keys */
+ r = set_ensure_put(&keys, &dns_resource_key_hash_ops, dns_transaction_key(t));
+ if (r < 0)
+ return r;
/*
* For mDNS, we want to coalesce as many open queries in pending transactions into one single
assert_se(sd_event_now(t->scope->manager->event, CLOCK_BOOTTIME, &ts) >= 0);
- LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) {
-
- /* Skip ourselves */
- if (other == t)
- continue;
-
- if (other->state != DNS_TRANSACTION_PENDING)
- continue;
-
- if (other->next_attempt_after > ts)
- continue;
+ for (bool restart = true; restart;) {
+ restart = false;
+ LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) {
+ size_t saved_packet_size;
+ bool append = false;
- if (qdcount >= UINT16_MAX)
- break;
+ /* Skip ourselves */
+ if (other == t)
+ continue;
- r = dns_packet_append_key(p, dns_transaction_key(other), 0, NULL);
+ if (other->state != DNS_TRANSACTION_PENDING)
+ continue;
- /*
- * If we can't stuff more questions into the packet, just give up.
- * One of the 'other' transactions will fire later and take care of the rest.
- */
- if (r == -EMSGSIZE)
- break;
+ if (other->next_attempt_after > ts)
+ continue;
- if (r < 0)
- return r;
+ if (!set_contains(keys, dns_transaction_key(other))) {
+ r = dns_packet_append_key(p, dns_transaction_key(other), 0, &saved_packet_size);
+ /* If we can't stuff more questions into the packet, just give up.
+ * One of the 'other' transactions will fire later and take care of the rest. */
+ if (r == -EMSGSIZE)
+ break;
+ if (r < 0)
+ return r;
- r = dns_transaction_prepare(other, ts);
- if (r <= 0)
- continue;
+ r = dns_packet_append_zone(p, t, dns_transaction_key(other), NULL);
+ if (r == -EMSGSIZE)
+ break;
+ if (r < 0)
+ return r;
- ts += transaction_get_resend_timeout(other);
+ append = true;
+ }
- r = sd_event_add_time(
- other->scope->manager->event,
- &other->timeout_event_source,
- CLOCK_BOOTTIME,
- ts, 0,
- on_transaction_timeout, other);
- if (r < 0)
- return r;
+ r = dns_transaction_prepare(other, ts);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ if (append)
+ dns_packet_truncate(p, saved_packet_size);
- (void) sd_event_source_set_description(other->timeout_event_source, "dns-transaction-timeout");
+ /* In this case, not only this transaction, but multiple transactions may be
+ * freed. Hence, we need to restart the loop. */
+ restart = true;
+ break;
+ }
- other->state = DNS_TRANSACTION_PENDING;
- other->next_attempt_after = ts;
+ usec_t timeout = transaction_get_resend_timeout(other);
+ r = dns_transaction_setup_timeout(other, timeout, usec_add(ts, timeout));
+ if (r < 0)
+ return r;
- qdcount++;
+ if (dns_key_is_shared(dns_transaction_key(other)))
+ add_known_answers = true;
- if (dns_key_is_shared(dns_transaction_key(other)))
- add_known_answers = true;
+ if (append) {
+ r = set_ensure_put(&keys, &dns_resource_key_hash_ops, dns_transaction_key(other));
+ if (r < 0)
+ return r;
+ }
- if (dns_transaction_key(other)->type == DNS_TYPE_ANY) {
- r = set_ensure_put(&keys, &dns_resource_key_hash_ops, dns_transaction_key(other));
- if (r < 0)
- return r;
+ qdcount++;
+ if (qdcount >= UINT16_MAX)
+ break;
}
}
- DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount);
-
/* Append known answer section if we're asking for any shared record */
if (add_known_answers) {
- r = dns_cache_export_shared_to_packet(&t->scope->cache, p);
+ r = dns_cache_export_shared_to_packet(&t->scope->cache, p, ts, 0);
if (r < 0)
return r;
+
+ ancount = be16toh(DNS_PACKET_HEADER(p)->ancount);
}
- SET_FOREACH(tkey, keys) {
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- bool tentative;
+ /* Then, create acctual packet. */
+ p = dns_packet_unref(p);
+ r = dns_packet_new_query(&p, t->scope->protocol, 0, false);
+ if (r < 0)
+ return r;
+
+ /* Questions */
+ DnsResourceKey *k;
+ SET_FOREACH(k, keys) {
+ r = dns_packet_append_key(p, k, 0, NULL);
+ if (r < 0)
+ return r;
+ }
+ DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount);
- r = dns_zone_lookup(&t->scope->zone, tkey, t->scope->link->ifindex, &answer, NULL, &tentative);
+ /* Known answers */
+ if (add_known_answers) {
+ r = dns_cache_export_shared_to_packet(&t->scope->cache, p, ts, ancount);
if (r < 0)
return r;
+ }
- r = dns_packet_append_answer(p, answer, &nscount);
+ /* Authorities */
+ nscount = 0;
+ SET_FOREACH(k, keys) {
+ r = dns_packet_append_zone(p, t, k, &nscount);
if (r < 0)
return r;
}
DNS_PACKET_HEADER(p)->nscount = htobe16(nscount);
t->sent = TAKE_PTR(p);
-
return 0;
}
if (!t->initial_jitter_scheduled &&
IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) {
- usec_t jitter, accuracy;
+ usec_t jitter;
- /* RFC 4795 Section 2.7 suggests all queries should be delayed by a random time from 0 to
- * JITTER_INTERVAL. */
+ /* RFC 4795 Section 2.7 suggests all LLMNR queries should be delayed by a random time from 0 to
+ * JITTER_INTERVAL.
+ * RFC 6762 Section 8.1 suggests initial probe queries should be delayed by a random time from
+ * 0 to 250ms. */
t->initial_jitter_scheduled = true;
+ t->n_attempts = 0;
switch (t->scope->protocol) {
case DNS_PROTOCOL_LLMNR:
jitter = random_u64_range(LLMNR_JITTER_INTERVAL_USEC);
- accuracy = LLMNR_JITTER_INTERVAL_USEC;
break;
case DNS_PROTOCOL_MDNS:
- jitter = usec_add(random_u64_range(MDNS_JITTER_RANGE_USEC), MDNS_JITTER_MIN_USEC);
- accuracy = MDNS_JITTER_RANGE_USEC;
+ if (t->probing)
+ jitter = random_u64_range(MDNS_PROBING_INTERVAL_USEC);
+ else
+ jitter = 0;
break;
default:
assert_not_reached();
}
- assert(!t->timeout_event_source);
-
- r = sd_event_add_time_relative(
- t->scope->manager->event,
- &t->timeout_event_source,
- CLOCK_BOOTTIME,
- jitter, accuracy,
- on_transaction_timeout, t);
+ r = dns_transaction_setup_timeout(t, jitter, ts);
if (r < 0)
return r;
- (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
-
- t->n_attempts = 0;
- t->next_attempt_after = ts;
- t->state = DNS_TRANSACTION_PENDING;
-
log_debug("Delaying %s transaction %" PRIu16 " for " USEC_FMT "us.",
dns_protocol_to_string(t->scope->protocol),
t->id,
return dns_transaction_go(t);
}
- ts += transaction_get_resend_timeout(t);
-
- r = sd_event_add_time(
- t->scope->manager->event,
- &t->timeout_event_source,
- CLOCK_BOOTTIME,
- ts, 0,
- on_transaction_timeout, t);
+ usec_t timeout = transaction_get_resend_timeout(t);
+ r = dns_transaction_setup_timeout(t, timeout, usec_add(ts, timeout));
if (r < 0)
return r;
- (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
-
- t->state = DNS_TRANSACTION_PENDING;
- t->next_attempt_after = ts;
-
return 1;
}
projects / thirdparty / systemd.git / commitdiff
