void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
DnsQuery *q;
DnsZoneItem *z;
Iterator i;
assert(t);
assert(!IN_SET(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. */
log_debug("Transaction on scope %s on %s/%s now complete with <%s>",
dns_protocol_to_string(t->scope->protocol),
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family),
dns_transaction_state_to_string(state));
t->state = state;
dns_transaction_stop(t);
/* Notify all queries that are interested, but make sure the
* transaction isn't freed while we are still looking at it */
t->block_gc++;
SET_FOREACH(q, t->queries, i)
dns_query_ready(q);
SET_FOREACH(z, t->zone_items, i)
dns_zone_item_ready(z);
t->block_gc--;
dns_transaction_gc(t);
}
int main(int argc, const char *argv[]) {
unsigned int i;
for (i = 0; i < ELEMENTSOF(af_names); i++) {
if (af_names[i]) {
assert_se(streq(af_to_name(i), af_names[i]));
assert_se(af_from_name(af_names[i]) == (int) i);
}
}
assert_se(af_to_name(af_max()) == NULL);
assert_se(af_to_name(-1) == NULL);
assert_se(af_from_name("huddlduddl") == AF_UNSPEC);
return 0;
}
static void print_local_addresses(struct local_address *a, unsigned n) {
unsigned i;
for (i = 0; i < n; i++) {
_cleanup_free_ char *b = NULL;
assert_se(in_addr_to_string(a[i].family, &a[i].address, &b) >= 0);
printf("%s if%i scope=%i metric=%u address=%s\n", af_to_name(a[i].family), a[i].ifindex, a[i].scope, a[i].metric, b);
}
}
static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) {
_cleanup_free_ char *pretty = NULL;
DnsZoneItem *z;
assert(t);
assert(p);
if (manager_our_packet(t->scope->manager, p) != 0)
return;
in_addr_to_string(p->family, &p->sender, &pretty);
log_debug("Transaction on scope %s on %s/%s got tentative packet from %s",
dns_protocol_to_string(t->scope->protocol),
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family),
pretty);
/* RFC 4795, Section 4.1 says that the peer with the
* lexicographically smaller IP address loses */
if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) {
log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
return;
}
log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
t->block_gc++;
while ((z = set_first(t->zone_items))) {
/* First, make sure the zone item drops the reference
* to us */
dns_zone_item_probe_stop(z);
/* Secondly, report this as conflict, so that we might
* look for a different hostname */
dns_zone_item_conflict(z);
}
t->block_gc--;
dns_transaction_gc(t);
}
static void test_hostname_lookup(sd_bus *bus, const char *name, int family, const char *result) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *req = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_free_ char *m = NULL;
const char *af;
int r;
af = family == AF_UNSPEC ? "AF_UNSPEC" : af_to_name(family);
/* If the name starts with a dot, we prefix one to three random labels */
if (startswith(name, ".")) {
prefix_random(name + 1, &m);
name = m;
}
assert_se(sd_bus_message_new_method_call(
bus,
&req,
"org.freedesktop.resolve1",
"/org/freedesktop/resolve1",
"org.freedesktop.resolve1.Manager",
"ResolveHostname") >= 0);
assert_se(sd_bus_message_append(req, "isit", 0, name, family, UINT64_C(0)) >= 0);
r = sd_bus_call(bus, req, SD_RESOLVED_QUERY_TIMEOUT_USEC, &error, &reply);
if (r < 0) {
assert_se(result);
assert_se(sd_bus_error_has_name(&error, result));
log_info("[OK] %s/%s resulted in <%s>.", name, af, error.name);
} else {
assert_se(!result);
log_info("[OK] %s/%s succeeded.", name, af);
}
}
int dns_transaction_go(DnsTransaction *t) {
bool had_stream;
usec_t ts;
int r;
assert(t);
had_stream = !!t->stream;
dns_transaction_stop(t);
log_debug("Excercising transaction on scope %s on %s/%s",
dns_protocol_to_string(t->scope->protocol),
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family));
if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) {
dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED);
return 0;
}
if (t->scope->protocol == DNS_PROTOCOL_LLMNR && had_stream) {
/* If we already tried via a stream, then we don't
* retry on LLMNR. See RFC 4795, Section 2.7. */
dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED);
return 0;
}
assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0);
t->n_attempts++;
t->start_usec = ts;
t->received = dns_packet_unref(t->received);
t->cached = dns_answer_unref(t->cached);
t->cached_rcode = 0;
/* Check the cache, but only if this transaction is not used
* for probing or verifying a zone item. */
if (set_isempty(t->zone_items)) {
/* Before trying the cache, let's make sure we figured out a
* server to use. Should this cause a change of server this
* might flush the cache. */
dns_scope_get_dns_server(t->scope);
/* Let's then prune all outdated entries */
dns_cache_prune(&t->scope->cache);
r = dns_cache_lookup(&t->scope->cache, t->key, &t->cached_rcode, &t->cached);
if (r < 0)
return r;
if (r > 0) {
if (t->cached_rcode == DNS_RCODE_SUCCESS)
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
else
dns_transaction_complete(t, DNS_TRANSACTION_FAILURE);
return 0;
}
}
if (t->scope->protocol == DNS_PROTOCOL_LLMNR && !t->initial_jitter) {
usec_t jitter;
/* RFC 4795 Section 2.7 suggests all queries should be
* delayed by a random time from 0 to JITTER_INTERVAL. */
t->initial_jitter = true;
random_bytes(&jitter, sizeof(jitter));
jitter %= LLMNR_JITTER_INTERVAL_USEC;
r = sd_event_add_time(
t->scope->manager->event,
&t->timeout_event_source,
clock_boottime_or_monotonic(),
ts + jitter,
LLMNR_JITTER_INTERVAL_USEC,
on_transaction_timeout, t);
if (r < 0)
return r;
t->n_attempts = 0;
t->state = DNS_TRANSACTION_PENDING;
log_debug("Delaying LLMNR transaction for " USEC_FMT "us.", jitter);
return 0;
}
/* Otherwise, we need to ask the network */
r = dns_transaction_make_packet(t);
if (r == -EDOM) {
/* Not the right request to make on this network?
* (i.e. an A request made on IPv6 or an AAAA request
* made on IPv4, on LLMNR or mDNS.) */
dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS);
return 0;
}
if (r < 0)
return r;
if (t->scope->protocol == DNS_PROTOCOL_LLMNR &&
(dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), "in-addr.arpa") > 0 ||
dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), "ip6.arpa") > 0)) {
/* RFC 4795, Section 2.4. says reverse lookups shall
* always be made via TCP on LLMNR */
r = dns_transaction_open_tcp(t);
} else {
/* Try via UDP, and if that fails due to large size try via TCP */
r = dns_transaction_emit(t);
if (r == -EMSGSIZE)
r = dns_transaction_open_tcp(t);
}
if (r == -ESRCH) {
/* No servers to send this to? */
dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS);
return 0;
} else if (r < 0) {
if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return 0;
}
/* Couldn't send? Try immediately again, with a new server */
dns_transaction_next_dns_server(t);
return dns_transaction_go(t);
}
r = sd_event_add_time(
t->scope->manager->event,
&t->timeout_event_source,
clock_boottime_or_monotonic(),
ts + transaction_get_resend_timeout(t), 0,
on_transaction_timeout, t);
if (r < 0)
return r;
t->state = DNS_TRANSACTION_PENDING;
return 1;
}
