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);
+ (void) set_remove(q->request_dns_stream->queries, q);
+ q->request_dns_stream = dns_stream_unref(q->request_dns_stream);
}
free(q->request_address_string);
#define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC)
#define DNS_STREAMS_MAX 128
+#define DNS_QUERIES_PER_STREAM 32
+
static void dns_stream_stop(DnsStream *s) {
assert(s);
s->n_written = 0;
f |= EPOLLOUT;
}
- if (!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size)
+
+ /* Let's read a packet if we haven't queued any yet. Except if we already hit a limit of parallel
+ * queries for this connection. */
+ if ((!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size) &&
+ set_size(s->queries) < DNS_QUERIES_PER_STREAM)
f |= EPOLLIN;
#if ENABLE_DNS_OVER_TLS
/* For handshake and clean closing purposes, TLS can override requested events */
- if (s->dnstls_events)
+ if (s->dnstls_events != 0)
f = s->dnstls_events;
#endif
_cleanup_(dns_stream_unrefp) _unused_ DnsStream *ref = dns_stream_ref(s); /* Protect stream while we process it */
assert(s);
+ assert(error >= 0);
+
+ /* Error is > 0 when the connection failed for some reason in the network stack. It's == 0 if we sent
+ * and receieved exactly one packet each (in the LLMNR client case). */
#if ENABLE_DNS_OVER_TLS
if (s->encrypted) {
static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
_cleanup_(dns_stream_unrefp) DnsStream *s = dns_stream_ref(userdata); /* Protect stream while we process it */
+ bool progressed = false;
int r;
assert(s);
if (ss < 0) {
if (!IN_SET(-ss, EINTR, EAGAIN))
return dns_stream_complete(s, -ss);
- } else
+ } else {
+ progressed = true;
s->n_written += ss;
+ }
/* Are we done? If so, disable the event source for EPOLLOUT */
if (s->n_written >= sizeof(s->write_size) + s->write_packet->size) {
return dns_stream_complete(s, -ss);
} else if (ss == 0)
return dns_stream_complete(s, ECONNRESET);
- else
+ else {
+ progressed = true;
s->n_read += ss;
+ }
}
if (s->n_read >= sizeof(s->read_size)) {
}
}
- if ((s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) &&
+ /* Call "complete" callback if finished reading and writing one packet, and there's nothing else left
+ * to write. */
+ if (s->type == DNS_STREAM_LLMNR_SEND &&
+ (s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) &&
+ ordered_set_isempty(s->write_queue) &&
(s->read_packet && s->n_read >= sizeof(s->read_size) + s->read_packet->size))
return dns_stream_complete(s, 0);
+ /* If we did something, let's restart the timeout event source */
+ if (progressed && s->timeout_event_source) {
+ r = sd_event_source_set_time(s->timeout_event_source, now(clock_boottime_or_monotonic()) + DNS_STREAM_TIMEOUT_USEC);
+ if (r < 0)
+ log_warning_errno(errno, "Couldn't restart TCP connection timeout, ignoring: %m");
+ }
+
return 0;
}
if (s->manager) {
LIST_REMOVE(streams, s->manager->dns_streams, s);
- s->manager->n_dns_streams--;
+ s->manager->n_dns_streams[s->type]--;
}
#if ENABLE_DNS_OVER_TLS
int dns_stream_new(
Manager *m,
DnsStream **ret,
+ DnsStreamType type,
DnsProtocol protocol,
int fd,
const union sockaddr_union *tfo_address) {
assert(m);
assert(ret);
+ assert(type >= 0);
+ assert(type < _DNS_STREAM_TYPE_MAX);
+ assert(protocol >= 0);
+ assert(protocol < _DNS_PROTOCOL_MAX);
assert(fd >= 0);
- if (m->n_dns_streams > DNS_STREAMS_MAX)
+ if (m->n_dns_streams[type] > DNS_STREAMS_MAX)
return -EBUSY;
s = new(DnsStream, 1);
(void) sd_event_source_set_description(s->timeout_event_source, "dns-stream-timeout");
LIST_PREPEND(streams, m->dns_streams, s);
- m->n_dns_streams++;
+ m->n_dns_streams[type]++;
s->manager = m;
s->fd = fd;
typedef struct DnsStream DnsStream;
+typedef enum DnsStreamType {
+ DNS_STREAM_LOOKUP, /* Outgoing connection to a classic DNS server */
+ DNS_STREAM_LLMNR_SEND, /* Outgoing LLMNR TCP lookup */
+ DNS_STREAM_LLMNR_RECV, /* Incoming LLMNR TCP lookup */
+ DNS_STREAM_STUB, /* Incoming DNS stub connection */
+ _DNS_STREAM_TYPE_MAX,
+ _DNS_STREAM_TYPE_INVALID = -1,
+} DnsStreamType;
+
#include "resolved-dns-packet.h"
#include "resolved-dns-transaction.h"
#include "resolved-manager.h"
Manager *manager;
unsigned n_ref;
+ DnsStreamType type;
DnsProtocol protocol;
int fd;
LIST_HEAD(DnsTransaction, transactions); /* when used by the transaction logic */
DnsServer *server; /* when used by the transaction logic */
- DnsQuery *query; /* when used by the DNS stub logic */
+ Set *queries; /* when used by the DNS stub logic */
/* used when DNS-over-TLS is enabled */
bool encrypted:1;
LIST_FIELDS(DnsStream, streams);
};
-int dns_stream_new(Manager *m, DnsStream **s, DnsProtocol protocol, int fd, const union sockaddr_union *tfo_address);
+int dns_stream_new(Manager *m, DnsStream **s, DnsStreamType type, DnsProtocol protocol, int fd, const union sockaddr_union *tfo_address);
#if ENABLE_DNS_OVER_TLS
int dns_stream_connect_tls(DnsStream *s, void *tls_session);
#endif
return 0;
}
-static void dns_stub_detach_stream(DnsStream *s) {
- assert(s);
-
- s->complete = NULL;
- s->on_packet = NULL;
- s->query = NULL;
-}
-
static int dns_stub_send(Manager *m, DnsStream *s, DnsPacket *p, DnsPacket *reply) {
int r;
assert_not_reached("Impossible state");
}
- /* If there's a packet to write set, let's leave the stream around */
- if (q->request_dns_stream && DNS_STREAM_QUEUED(q->request_dns_stream)) {
-
- /* Detach the stream from our query (make it an orphan), but do not drop the reference to it. The
- * default completion action of the stream will drop the reference. */
-
- dns_stub_detach_stream(q->request_dns_stream);
- q->request_dns_stream = NULL;
- }
-
dns_query_free(q);
}
static int dns_stub_stream_complete(DnsStream *s, int error) {
assert(s);
- log_debug_errno(error, "DNS TCP connection terminated, destroying query: %m");
+ log_debug_errno(error, "DNS TCP connection terminated, destroying queries: %m");
+
+ for (;;) {
+ DnsQuery *q;
+
+ q = set_first(s->queries);
+ if (!q)
+ break;
- assert(s->query);
- dns_query_free(s->query);
+ dns_query_free(q);
+ }
+ /* This drops the implicit ref we keep around since it was allocated, as incoming stub connections
+ * should be kept as long as the client wants to. */
+ dns_stream_unref(s);
return 0;
}
assert(p);
assert(p->protocol == DNS_PROTOCOL_DNS);
- /* Takes ownership of the *s stream object */
-
if (in_addr_is_localhost(p->family, &p->sender) <= 0 ||
in_addr_is_localhost(p->family, &p->destination) <= 0) {
log_error("Got packet on unexpected IP range, refusing.");
q->complete = dns_stub_query_complete;
if (s) {
- s->on_packet = NULL;
- s->complete = dns_stub_stream_complete;
- s->query = q;
+ /* Remember which queries belong to this stream, so that we can cancel them when the stream
+ * is disconnected early */
+
+ r = set_ensure_allocated(&s->queries, &trivial_hash_ops);
+ if (r < 0) {
+ log_oom();
+ goto fail;
+ }
+
+ if (set_put(s->queries, q) < 0) {
+ log_oom();
+ goto fail;
+ }
}
r = dns_query_go(q);
return;
fail:
- if (s && DNS_STREAM_QUEUED(s))
- dns_stub_detach_stream(s);
-
dns_query_free(q);
}
} else
log_debug("Invalid DNS stub TCP packet, ignoring.");
- /* Drop the reference to the stream. Either a query was created and added its own reference to the stream now,
- * or that didn't happen in which case we want to free the stream */
- dns_stream_unref(s);
-
return 0;
}
return -errno;
}
- r = dns_stream_new(m, &stream, DNS_PROTOCOL_DNS, cfd, NULL);
+ r = dns_stream_new(m, &stream, DNS_STREAM_STUB, DNS_PROTOCOL_DNS, cfd, NULL);
if (r < 0) {
safe_close(cfd);
return r;
}
stream->on_packet = on_dns_stub_stream_packet;
+ stream->complete = dns_stub_stream_complete;
- /* We let the reference to the stream dangling here, it will either be dropped by the default "complete" action
- * of the stream, or by our packet callback, or when the manager is shut down. */
+ /* We let the reference to the stream dangle here, it will be dropped later by the complete callback. */
return 0;
}
if (t)
return dns_transaction_on_stream_packet(t, p);
- /* Ignore incorrect transaction id as transaction can have been canceled */
- if (dns_packet_validate_reply(p) <= 0) {
- log_debug("Invalid TCP reply packet.");
- on_stream_complete(s, 0);
- }
-
+ /* Ignore incorrect transaction id as an old transaction can have been canceled. */
+ log_debug("Received unexpected TCP reply packet with id %" PRIu16 ", ignoring.", t->id);
return 0;
}
}
static int dns_transaction_emit_tcp(DnsTransaction *t) {
- _cleanup_close_ int fd = -1;
_cleanup_(dns_stream_unrefp) DnsStream *s = NULL;
+ _cleanup_close_ int fd = -1;
union sockaddr_union sa;
+ DnsStreamType type;
int r;
assert(t);
else
fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, dns_port_for_feature_level(t->current_feature_level), &sa);
+ type = DNS_STREAM_LOOKUP;
break;
case DNS_PROTOCOL_LLMNR:
fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT, &sa);
}
+ type = DNS_STREAM_LLMNR_SEND;
break;
default:
if (fd < 0)
return fd;
- r = dns_stream_new(t->scope->manager, &s, t->scope->protocol, fd, &sa);
+ r = dns_stream_new(t->scope->manager, &s, type, t->scope->protocol, fd, &sa);
if (r < 0)
return r;
if (t->server) {
dns_server_unref_stream(t->server);
- t->server->stream = dns_stream_ref(s);
s->server = dns_server_ref(t->server);
+ t->server->stream = dns_stream_ref(s);
}
s->complete = on_stream_complete;
return -errno;
}
- r = dns_stream_new(m, &stream, DNS_PROTOCOL_LLMNR, cfd, NULL);
+ r = dns_stream_new(m, &stream, DNS_STREAM_LLMNR_RECV, DNS_PROTOCOL_LLMNR, cfd, NULL);
if (r < 0) {
safe_close(cfd);
return r;
}
stream->on_packet = on_llmnr_stream_packet;
+ /* We don't configure a "complete" handler here, we rely on the default handler than simply drops the
+ * reference to the stream, thus freeing it */
return 0;
}
unsigned n_dns_queries;
LIST_HEAD(DnsStream, dns_streams);
- unsigned n_dns_streams;
+ unsigned n_dns_streams[_DNS_STREAM_TYPE_MAX];
/* Unicast dns */
LIST_HEAD(DnsServer, dns_servers);
projects / thirdparty / systemd.git / commitdiff
