along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
+#include "af-list.h"
+
#include "resolved-dns-query.h"
#include "resolved-dns-domain.h"
-#define TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+/* After how much time to repeat classic DNS requests */
+#define DNS_TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
+
+/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
+#define LLMNR_TRANSACTION_TIMEOUT_USEC (1 * USEC_PER_SEC)
+
+/* How long to wait for the query in total */
#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
-#define ATTEMPTS_MAX 8
+
+/* Maximum attempts to send DNS requests, across all DNS servers */
+#define DNS_TRANSACTION_ATTEMPTS_MAX 8
+
+/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
+#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
+
+#define CNAME_MAX 8
+#define QUERIES_MAX 2048
+
+#define TRANSACTION_TIMEOUT_USEC(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_TIMEOUT_USEC : DNS_TRANSACTION_TIMEOUT_USEC)
+#define TRANSACTION_ATTEMPTS_MAX(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)
+
+static int dns_query_transaction_go(DnsQueryTransaction *t);
DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) {
+ DnsQuery *q;
+
if (!t)
return NULL;
sd_event_source_unref(t->timeout_event_source);
+ dns_question_unref(t->question);
dns_packet_unref(t->sent);
dns_packet_unref(t->received);
+ dns_answer_unref(t->cached);
+
+ dns_stream_free(t->stream);
- sd_event_source_unref(t->tcp_event_source);
- safe_close(t->tcp_fd);
+ if (t->scope) {
+ LIST_REMOVE(transactions_by_scope, t->scope->transactions, t);
- 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->id != 0)
+ hashmap_remove(t->scope->manager->dns_query_transactions, UINT_TO_PTR(t->id));
}
- if (t->scope)
- LIST_REMOVE(transactions_by_scope, t->scope->transactions, t);
+ while ((q = set_steal_first(t->queries)))
+ set_remove(q->transactions, t);
+
+ set_free(t->queries);
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) {
+static void dns_query_transaction_gc(DnsQueryTransaction *t) {
+ assert(t);
+
+ if (t->block_gc > 0)
+ return;
+
+ if (set_isempty(t->queries))
+ dns_query_transaction_free(t);
+}
+
+static int dns_query_transaction_new(DnsQueryTransaction **ret, DnsScope *s, DnsQuestion *q) {
_cleanup_(dns_query_transaction_freep) DnsQueryTransaction *t = NULL;
int r;
- assert(q);
+ assert(ret);
assert(s);
+ assert(q);
- r = hashmap_ensure_allocated(&q->manager->dns_query_transactions, NULL, NULL);
+ r = hashmap_ensure_allocated(&s->manager->dns_query_transactions, NULL, NULL);
if (r < 0)
return r;
if (!t)
return -ENOMEM;
- t->tcp_fd = -1;
+ t->question = dns_question_ref(q);
do
random_bytes(&t->id, sizeof(t->id));
while (t->id == 0 ||
- hashmap_get(q->manager->dns_query_transactions, UINT_TO_PTR(t->id)));
+ hashmap_get(s->manager->dns_query_transactions, UINT_TO_PTR(t->id)));
- r = hashmap_put(q->manager->dns_query_transactions, UINT_TO_PTR(t->id), t);
+ r = hashmap_put(s->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;
assert(t);
t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
- t->tcp_event_source = sd_event_source_unref(t->tcp_event_source);
- t->tcp_fd = safe_close(t->tcp_fd);
+ t->stream = dns_stream_free(t->stream);
}
-static void dns_query_transaction_set_state(DnsQueryTransaction *t, DnsQueryState state) {
+void dns_query_transaction_complete(DnsQueryTransaction *t, DnsQueryState state) {
+ DnsQuery *q;
+ Iterator i;
+
assert(t);
+ assert(!IN_SET(state, DNS_QUERY_NULL, DNS_QUERY_PENDING));
+ assert(IN_SET(t->state, DNS_QUERY_NULL, DNS_QUERY_PENDING));
- if (t->state == state)
- return;
+ /* 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_query_state_to_string(state));
t->state = state;
- if (state != DNS_QUERY_SENT) {
- dns_query_transaction_stop(t);
- dns_query_finish(t->query);
- }
+ dns_query_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);
+ t->block_gc--;
+
+ dns_query_transaction_gc(t);
}
-static int on_tcp_ready(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
- DnsQueryTransaction *t = userdata;
- int r;
+static int on_stream_complete(DnsStream *s, int error) {
+ _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+ DnsQueryTransaction *t;
- assert(t);
+ assert(s);
+ assert(s->transaction);
- if (revents & EPOLLOUT) {
- struct iovec iov[2];
- be16_t sz;
- ssize_t ss;
+ /* Copy the data we care about out of the stream before we
+ * destroy it. */
+ t = s->transaction;
+ p = dns_packet_ref(s->read_packet);
- sz = htobe16(t->sent->size);
+ t->stream = dns_stream_free(t->stream);
- iov[0].iov_base = &sz;
- iov[0].iov_len = sizeof(sz);
- iov[1].iov_base = DNS_PACKET_DATA(t->sent);
- iov[1].iov_len = t->sent->size;
+ if (error != 0) {
+ dns_query_transaction_complete(t, DNS_QUERY_RESOURCES);
+ return 0;
+ }
- IOVEC_INCREMENT(iov, 2, t->tcp_written);
+ t->block_gc++;
+ dns_query_transaction_process_reply(t, p);
+ t->block_gc--;
- ss = writev(fd, iov, 2);
- if (ss < 0) {
- if (errno != EINTR && errno != EAGAIN) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return -errno;
- }
- } else
- t->tcp_written += ss;
+ /* If the response wasn't useful, then complete the transition now */
+ if (t->state == DNS_QUERY_PENDING)
+ dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY);
- /* Are we done? If so, disable the event source for EPOLLOUT */
- if (t->tcp_written >= sizeof(sz) + t->sent->size) {
- r = sd_event_source_set_io_events(s, EPOLLIN);
- if (r < 0) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return r;
- }
- }
- }
+ return 0;
+}
- if (revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) {
+static int dns_query_transaction_open_tcp(DnsQueryTransaction *t) {
+ _cleanup_close_ int fd = -1;
+ int r;
- if (t->tcp_read < sizeof(t->tcp_read_size)) {
- ssize_t ss;
+ assert(t);
- ss = read(fd, (uint8_t*) &t->tcp_read_size + t->tcp_read, sizeof(t->tcp_read_size) - t->tcp_read);
- if (ss < 0) {
- if (errno != EINTR && errno != EAGAIN) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return -errno;
- }
- } else if (ss == 0) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return -EIO;
- } else
- t->tcp_read += ss;
- }
+ if (t->stream)
+ return 0;
- if (t->tcp_read >= sizeof(t->tcp_read_size)) {
+ if (t->scope->protocol == DNS_PROTOCOL_DNS)
+ fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53);
+ else if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
+
+ /* When we already received a query to this (but it was truncated), send to its sender address */
+ if (t->received)
+ fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port);
+ else {
+ union in_addr_union address;
+ int family;
+
+ /* Otherwise, try to talk to the owner of a
+ * the IP address, in case this is a reverse
+ * PTR lookup */
+ r = dns_question_extract_reverse_address(t->question, &family, &address);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return -EINVAL;
- if (be16toh(t->tcp_read_size) < DNS_PACKET_HEADER_SIZE) {
- dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
- return -EBADMSG;
- }
+ fd = dns_scope_tcp_socket(t->scope, family, &address, 5355);
+ }
+ } else
+ return -EAFNOSUPPORT;
- if (t->tcp_read < sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) {
- ssize_t ss;
+ if (fd < 0)
+ return fd;
- if (!t->received) {
- r = dns_packet_new(&t->received, be16toh(t->tcp_read_size));
- if (r < 0) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return r;
- }
- }
+ r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd);
+ if (r < 0)
+ return r;
- ss = read(fd,
- (uint8_t*) DNS_PACKET_DATA(t->received) + t->tcp_read - sizeof(t->tcp_read_size),
- sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size) - t->tcp_read);
- if (ss < 0) {
- if (errno != EINTR && errno != EAGAIN) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return -errno;
- }
- } else if (ss == 0) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
- return -EIO;
- } else
- t->tcp_read += ss;
- }
+ fd = -1;
- if (t->tcp_read >= sizeof(t->tcp_read_size) + be16toh(t->tcp_read_size)) {
- t->received->size = be16toh(t->tcp_read_size);
- dns_query_transaction_reply(t, t->received);
- return 0;
- }
- }
+ r = dns_stream_write_packet(t->stream, t->sent);
+ if (r < 0) {
+ t->stream = dns_stream_free(t->stream);
+ return r;
}
+ t->received = dns_packet_unref(t->received);
+ t->stream->complete = on_stream_complete;
+ t->stream->transaction = t;
+
+ /* The interface index is difficult to determine if we are
+ * connecting to the local host, hence fill this in right away
+ * instead of determining it from the socket */
+ if (t->scope->link)
+ t->stream->ifindex = t->scope->link->ifindex;
+
return 0;
}
-static int dns_query_transaction_start_tcp(DnsQueryTransaction *t) {
+void dns_query_transaction_process_reply(DnsQueryTransaction *t, DnsPacket *p) {
int r;
assert(t);
+ assert(p);
+ assert(t->state == DNS_QUERY_PENDING);
- if (t->tcp_fd >= 0)
- return 0;
+ /* Note that this call might invalidate the query. Callers
+ * should hence not attempt to access the query or transaction
+ * after calling this function. */
- t->tcp_written = 0;
- t->tcp_read = 0;
- t->received = dns_packet_unref(t->received);
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
+ assert(t->scope->link);
- t->tcp_fd = dns_scope_tcp_socket(t->scope);
- if (t->tcp_fd < 0)
- return t->tcp_fd;
+ /* For LLMNR we will not accept any packets from other
+ * interfaces */
- r = sd_event_add_io(t->query->manager->event, &t->tcp_event_source, t->tcp_fd, EPOLLIN|EPOLLOUT, on_tcp_ready, t);
- if (r < 0) {
- t->tcp_fd = safe_close(t->tcp_fd);
- return r;
+ if (p->ifindex != t->scope->link->ifindex)
+ return;
+
+ if (p->family != t->scope->family)
+ return;
+
+ /* Tentative replies shall be discarded, see RFC 4795,
+ * 2.1.1 */
+
+ if (DNS_PACKET_T(p))
+ return;
}
- return 0;
-}
+ if (t->scope->protocol == DNS_PROTOCOL_DNS) {
-void dns_query_transaction_reply(DnsQueryTransaction *t, DnsPacket *p) {
- int r;
+ /* For DNS we are fine with accepting packets on any
+ * interface, but the source IP address must be one of
+ * a valid DNS server */
- assert(t);
- assert(p);
+ if (!dns_scope_good_dns_server(t->scope, p->family, &p->sender))
+ return;
- if (t->state != DNS_QUERY_SENT)
- return;
+ if (p->sender_port != 53)
+ return;
+ }
if (t->received != p) {
dns_packet_unref(t->received);
t->received = dns_packet_ref(p);
}
- if (t->tcp_fd >= 0) {
+ if (p->ipproto == IPPROTO_TCP) {
if (DNS_PACKET_TC(p)) {
/* Truncated via TCP? Somebody must be fucking with us */
- dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY);
return;
}
if (DNS_PACKET_ID(p) != t->id) {
/* Not the reply to our query? Somebody must be fucking with us */
- dns_query_transaction_set_state(t, DNS_QUERY_INVALID_REPLY);
+ dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY);
return;
}
}
if (DNS_PACKET_TC(p)) {
/* Response was truncated, let's try again with good old TCP */
- r = dns_query_transaction_start_tcp(t);
+ r = dns_query_transaction_open_tcp(t);
+ if (r == -ESRCH) {
+ /* No servers found? Damn! */
+ dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS);
+ return;
+ }
if (r < 0) {
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ /* On LLMNR, if we cannot connect to the host,
+ * we immediately give up */
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
+ dns_query_transaction_complete(t, DNS_QUERY_RESOURCES);
+ return;
+ }
+
+ /* On DNS, couldn't send? Try immediately again, with a new server */
+ dns_scope_next_dns_server(t->scope);
+
+ r = dns_query_transaction_go(t);
+ if (r < 0) {
+ dns_query_transaction_complete(t, DNS_QUERY_RESOURCES);
+ return;
+ }
+
return;
}
}
+ /* Parse and update the cache */
+ r = dns_packet_extract(p);
+ if (r < 0) {
+ dns_query_transaction_complete(t, DNS_QUERY_INVALID_REPLY);
+ return;
+ }
+
+ /* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
+ dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0);
+
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
- dns_query_transaction_set_state(t, DNS_QUERY_SUCCESS);
+ dns_query_transaction_complete(t, DNS_QUERY_SUCCESS);
else
- dns_query_transaction_set_state(t, DNS_QUERY_FAILURE);
+ dns_query_transaction_complete(t, DNS_QUERY_FAILURE);
}
static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) {
/* Timeout reached? Try again, with a new server */
dns_scope_next_dns_server(t->scope);
- r = dns_query_transaction_start(t);
+ r = dns_query_transaction_go(t);
if (r < 0)
- dns_query_transaction_set_state(t, DNS_QUERY_RESOURCES);
+ dns_query_transaction_complete(t, DNS_QUERY_RESOURCES);
return 0;
}
static int dns_query_make_packet(DnsQueryTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
- unsigned n;
+ unsigned n, added = 0;
int r;
assert(t);
if (t->sent)
return 0;
- r = dns_packet_new_query(&p, 0);
+ r = dns_packet_new_query(&p, t->scope->protocol, 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);
+ for (n = 0; n < t->question->n_keys; n++) {
+ r = dns_scope_good_key(t->scope, t->question->keys[n]);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ r = dns_packet_append_key(p, t->question->keys[n], NULL);
if (r < 0)
return r;
+
+ added++;
}
- DNS_PACKET_HEADER(p)->qdcount = htobe16(t->query->n_keys);
+ if (added <= 0)
+ return -EDOM;
+
+ DNS_PACKET_HEADER(p)->qdcount = htobe16(added);
DNS_PACKET_HEADER(p)->id = t->id;
t->sent = p;
return 0;
}
-int dns_query_transaction_start(DnsQueryTransaction *t) {
+static int dns_query_transaction_go(DnsQueryTransaction *t) {
+ bool had_stream;
int r;
assert(t);
+ had_stream = !!t->stream;
+
dns_query_transaction_stop(t);
- if (t->n_attempts >= ATTEMPTS_MAX) {
- dns_query_transaction_set_state(t, DNS_QUERY_ATTEMPTS_MAX);
+ log_debug("Beginning 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)) {
+ dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
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_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
+ return 0;
+ }
+
t->n_attempts++;
+ t->received = dns_packet_unref(t->received);
+ t->cached = dns_answer_unref(t->cached);
+ t->cached_rcode = 0;
- r = dns_query_make_packet(t);
+ /* First, let's try the cache */
+ dns_cache_prune(&t->scope->cache);
+ r = dns_cache_lookup(&t->scope->cache, t->question, &t->cached_rcode, &t->cached);
if (r < 0)
return r;
+ if (r > 0) {
+ if (t->cached_rcode == DNS_RCODE_SUCCESS)
+ dns_query_transaction_complete(t, DNS_QUERY_SUCCESS);
+ else
+ dns_query_transaction_complete(t, DNS_QUERY_FAILURE);
+ return 0;
+ }
- /* Try via UDP, and if that fails due to large size try via TCP */
- r = dns_scope_send(t->scope, t->sent);
- if (r == -EMSGSIZE)
- r = dns_query_transaction_start_tcp(t);
+ /* Otherwise, we need to ask the network */
+ r = dns_query_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_query_transaction_complete(t, DNS_QUERY_NO_SERVERS);
+ return 0;
+ }
+ if (r < 0)
+ return r;
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR &&
+ (dns_question_endswith(t->question, "in-addr.arpa") > 0 ||
+ dns_question_endswith(t->question, "ip6.arpa") > 0)) {
+
+ /* RFC 4795, Section 2.4. says reverse lookups shall
+ * always be made via TCP on LLMNR */
+ r = dns_query_transaction_open_tcp(t);
+ } else {
+ /* Try via UDP, and if that fails due to large size try via TCP */
+ r = dns_scope_send(t->scope, t->sent);
+ if (r == -EMSGSIZE)
+ r = dns_query_transaction_open_tcp(t);
+ }
if (r == -ESRCH) {
- dns_query_transaction_set_state(t, DNS_QUERY_NO_SERVERS);
+ /* No servers to send this to? */
+ dns_query_transaction_complete(t, DNS_QUERY_NO_SERVERS);
return 0;
}
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);
+ return dns_query_transaction_go(t);
}
- r = 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);
+ r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC(t), 0, on_transaction_timeout, t);
if (r < 0)
return r;
- dns_query_transaction_set_state(t, DNS_QUERY_SENT);
+ t->state = DNS_QUERY_PENDING;
return 1;
}
DnsQuery *dns_query_free(DnsQuery *q) {
- unsigned n;
+ DnsQueryTransaction *t;
if (!q)
return NULL;
sd_bus_message_unref(q->request);
- dns_packet_unref(q->received);
+
+ dns_question_unref(q->question);
+ dns_answer_unref(q->answer);
+
sd_event_source_unref(q->timeout_event_source);
- while (q->transactions)
- dns_query_transaction_free(q->transactions);
+ while ((t = set_steal_first(q->transactions))) {
+ set_remove(t->queries, q);
+ dns_query_transaction_gc(t);
+ }
+
+ set_free(q->transactions);
- if (q->manager)
+ if (q->manager) {
LIST_REMOVE(queries, q->manager->dns_queries, q);
+ q->manager->n_dns_queries--;
+ }
- 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) {
+int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question) {
_cleanup_(dns_query_freep) DnsQuery *q = NULL;
- DnsScope *s, *first = NULL;
- DnsScopeMatch found = DNS_SCOPE_NO;
- const char *name = NULL;
- int n, r;
+ unsigned i;
+ int r;
assert(m);
+ assert(question);
- if (n_keys <= 0 || n_keys >= 65535)
- return -EINVAL;
+ r = dns_question_is_valid(question);
+ if (r < 0)
+ return r;
- assert(keys);
+ if (m->n_dns_queries >= QUERIES_MAX)
+ return -EBUSY;
q = new0(DnsQuery, 1);
if (!q)
return -ENOMEM;
- q->keys = new(DnsResourceKey, n_keys);
- if (!q->keys)
- return -ENOMEM;
+ q->question = dns_question_ref(question);
- 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;
+ for (i = 0; i < question->n_keys; i++) {
+ _cleanup_free_ char *p;
+
+ r = dns_resource_key_to_string(question->keys[i], &p);
+ if (r < 0)
+ return r;
- if (!name)
- name = q->keys[q->n_keys].name;
- else if (!dns_name_equal(name, q->keys[q->n_keys].name))
- return -EINVAL;
+ log_debug("Looking up RR for %s", p);
}
LIST_PREPEND(queries, m->dns_queries, q);
+ m->n_dns_queries++;
q->manager = m;
- LIST_FOREACH(scopes, s, m->dns_scopes) {
+ if (ret)
+ *ret = q;
+ q = NULL;
+
+ return 0;
+}
+
+static void dns_query_stop(DnsQuery *q) {
+ DnsQueryTransaction *t;
+
+ assert(q);
+
+ q->timeout_event_source = sd_event_source_unref(q->timeout_event_source);
+
+ while ((t = set_steal_first(q->transactions))) {
+ set_remove(t->queries, q);
+ dns_query_transaction_gc(t);
+ }
+}
+
+static void dns_query_complete(DnsQuery *q, DnsQueryState state) {
+ assert(q);
+ assert(!IN_SET(state, DNS_QUERY_NULL, DNS_QUERY_PENDING));
+ assert(IN_SET(q->state, DNS_QUERY_NULL, DNS_QUERY_PENDING));
+
+ /* 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_QUERY_TIMEOUT);
+ return 0;
+}
+
+static int dns_query_add_transaction(DnsQuery *q, DnsScope *s, DnsResourceKey *key) {
+ _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
+ DnsQueryTransaction *t;
+ int r;
+
+ assert(q);
+
+ r = set_ensure_allocated(&q->transactions, NULL, NULL);
+ if (r < 0)
+ return r;
+
+ if (key) {
+ question = dns_question_new(1);
+ if (!question)
+ return -ENOMEM;
+
+ r = dns_question_add(question, key);
+ if (r < 0)
+ return r;
+ } else
+ question = dns_question_ref(q->question);
+
+ LIST_FOREACH(transactions_by_scope, t, s->transactions)
+ if (dns_question_is_superset(t->question, question))
+ break;
+
+ if (!t) {
+ r = dns_query_transaction_new(&t, s, question);
+ if (r < 0)
+ return r;
+ }
+
+ r = set_ensure_allocated(&t->queries, NULL, NULL);
+ if (r < 0)
+ goto fail;
+
+ r = set_put(t->queries, q);
+ if (r < 0)
+ goto fail;
+
+ r = set_put(q->transactions, t);
+ if (r < 0) {
+ set_remove(t->queries, q);
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ dns_query_transaction_gc(t);
+ return r;
+}
+
+static int dns_query_add_transaction_split(DnsQuery *q, DnsScope *s) {
+ int r;
+
+ assert(q);
+ assert(s);
+
+ if (s->protocol == DNS_PROTOCOL_MDNS) {
+ r = dns_query_add_transaction(q, s, NULL);
+ if (r < 0)
+ return r;
+ } else {
+ unsigned i;
+
+ /* On DNS and LLMNR we can only send a single
+ * question per datagram, hence issue multiple
+ * transactions. */
+
+ 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;
+}
+
+int dns_query_go(DnsQuery *q) {
+ DnsScopeMatch found = DNS_SCOPE_NO;
+ DnsScope *s, *first = NULL;
+ DnsQueryTransaction *t;
+ const char *name;
+ Iterator i;
+ int r;
+
+ assert(q);
+
+ if (q->state != DNS_QUERY_NULL)
+ return 0;
+
+ assert(q->question);
+ assert(q->question->n_keys > 0);
+
+ name = DNS_RESOURCE_KEY_NAME(q->question->keys[0]);
+
+ LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
DnsScopeMatch match;
- match = dns_scope_test(s, name);
+ match = dns_scope_good_domain(s, name);
if (match < 0)
return match;
}
if (found == DNS_SCOPE_NO)
- return -ENETDOWN;
+ return -ESRCH;
- r = dns_query_transaction_new(q, NULL, first);
+ r = dns_query_add_transaction_split(q, first);
if (r < 0)
return r;
- n = 1;
LIST_FOREACH(scopes, s, first->scopes_next) {
DnsScopeMatch match;
- match = dns_scope_test(s, name);
+ match = dns_scope_good_domain(s, name);
if (match < 0)
return match;
if (match != found)
continue;
- r = dns_query_transaction_new(q, NULL, s);
+ r = dns_query_add_transaction_split(q, 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;
+ q->answer = dns_answer_unref(q->answer);
+ q->answer_ifindex = 0;
+ q->answer_rcode = 0;
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);
+ q->state = DNS_QUERY_PENDING;
+ q->block_ready++;
- 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;
+ SET_FOREACH(t, q->transactions, i) {
+ if (t->state == DNS_QUERY_NULL) {
+ r = dns_query_transaction_go(t);
+ if (r < 0)
+ goto fail;
+ }
}
- return 0;
+ q->block_ready--;
+ dns_query_ready(q);
-fail:
- while (q->transactions)
- dns_query_transaction_free(q->transactions);
+ return 1;
+fail:
+ dns_query_stop(q);
return r;
}
-void dns_query_finish(DnsQuery *q) {
+void dns_query_ready(DnsQuery *q) {
DnsQueryTransaction *t;
DnsQueryState state = DNS_QUERY_NO_SERVERS;
- DnsPacket *received = NULL;
+ _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
+ int rcode = 0;
+ DnsScope *scope = NULL;
+ bool pending = false;
+ Iterator i;
assert(q);
+ assert(IN_SET(q->state, DNS_QUERY_NULL, DNS_QUERY_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->state != DNS_QUERY_SENT)
+ if (q->block_ready > 0)
return;
- LIST_FOREACH(transactions_by_query, t, q->transactions) {
+ SET_FOREACH(t, q->transactions, i) {
- /* 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;
+ /* If we found a successful answer, ignore all answers from other scopes */
+ if (state == DNS_QUERY_SUCCESS && t->scope != scope)
+ continue;
+
+ /* One of the transactions is still going on, let's maybe wait for it */
+ if (IN_SET(t->state, DNS_QUERY_PENDING, DNS_QUERY_NULL)) {
+ pending = true;
+ continue;
+ }
- /* One of the transactions is successful, let's use it */
+ /* One of the transactions is successful, let's use
+ * it, and copy its data out */
if (t->state == DNS_QUERY_SUCCESS) {
- q->received = dns_packet_ref(t->received);
- dns_query_set_state(q, DNS_QUERY_SUCCESS);
- return;
+ DnsAnswer *a;
+
+ if (t->received) {
+ rcode = DNS_PACKET_RCODE(t->received);
+ a = t->received->answer;
+ } else {
+ rcode = t->cached_rcode;
+ a = t->cached;
+ }
+
+ if (state == DNS_QUERY_SUCCESS) {
+ DnsAnswer *merged;
+
+ merged = dns_answer_merge(answer, a);
+ if (!merged) {
+ dns_query_complete(q, DNS_QUERY_RESOURCES);
+ return;
+ }
+
+ dns_answer_unref(answer);
+ answer = merged;
+ } else {
+ dns_answer_unref(answer);
+ answer = dns_answer_ref(a);
+ }
+
+ scope = t->scope;
+ state = DNS_QUERY_SUCCESS;
+ continue;
}
/* One of the transactions has failed, let's see
* whether we find anything better, but if not, return
- * its response packet */
- if (t->state == DNS_QUERY_FAILURE) {
- received = t->received;
+ * its response data */
+ if (state != DNS_QUERY_SUCCESS && t->state == DNS_QUERY_FAILURE) {
+ DnsAnswer *a;
+
+ if (t->received) {
+ rcode = DNS_PACKET_RCODE(t->received);
+ a = t->received->answer;
+ } else {
+ rcode = t->cached_rcode;
+ a = t->cached;
+ }
+
+ dns_answer_unref(answer);
+ answer = dns_answer_ref(a);
+
+ scope = t->scope;
state = DNS_QUERY_FAILURE;
continue;
}
state = t->state;
}
- if (state == DNS_QUERY_FAILURE)
- q->received = dns_packet_ref(received);
+ if (pending) {
- dns_query_set_state(q, state);
+ /* If so far we weren't successful, and there's
+ * something still pending, then wait for it */
+ if (state != DNS_QUERY_SUCCESS)
+ 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_QUERY_PENDING, DNS_QUERY_NULL))
+ return;
+ }
+ }
+
+ if (IN_SET(state, DNS_QUERY_SUCCESS, DNS_QUERY_FAILURE)) {
+ q->answer = dns_answer_ref(answer);
+ q->answer_rcode = rcode;
+ q->answer_ifindex = (scope && scope->link) ? scope->link->ifindex : 0;
+ }
+
+ dns_query_complete(q, state);
}
+
+int dns_query_cname_redirect(DnsQuery *q, const char *name) {
+ _cleanup_(dns_question_unrefp) DnsQuestion *nq = NULL;
+ int r;
+
+ assert(q);
+
+ if (q->n_cname_redirects > CNAME_MAX)
+ return -ELOOP;
+
+ r = dns_question_cname_redirect(q->question, name, &nq);
+ if (r < 0)
+ return r;
+
+ dns_question_unref(q->question);
+ q->question = nq;
+ nq = NULL;
+
+ q->n_cname_redirects++;
+
+ dns_query_stop(q);
+ q->state = DNS_QUERY_NULL;
+
+ return 0;
+}
+
+static const char* const dns_query_state_table[_DNS_QUERY_STATE_MAX] = {
+ [DNS_QUERY_NULL] = "null",
+ [DNS_QUERY_PENDING] = "pending",
+ [DNS_QUERY_FAILURE] = "failure",
+ [DNS_QUERY_SUCCESS] = "success",
+ [DNS_QUERY_NO_SERVERS] = "no-servers",
+ [DNS_QUERY_TIMEOUT] = "timeout",
+ [DNS_QUERY_ATTEMPTS_MAX] = "attempts-max",
+ [DNS_QUERY_INVALID_REPLY] = "invalid-reply",
+ [DNS_QUERY_RESOURCES] = "resources",
+ [DNS_QUERY_ABORTED] = "aborted",
+};
+DEFINE_STRING_TABLE_LOOKUP(dns_query_state, DnsQueryState);
~ianmdlvl / elogind.git / blobdiff