MEDIUM: mux-quic: implement http-request timeout
Implement http-request timeout for QUIC MUX. It is used when the
connection is opened and is triggered if no HTTP request is received in
time. By HTTP request we mean at least a QUIC stream with a full header
section. Then qcs instance is attached to a sedesc and upper layer is
then responsible to wait for the rest of the request.
This timeout is also used when new QUIC streams are opened during the
connection lifetime to wait for full HTTP request on them. As it's
possible to demux multiple streams in parallel with QUIC, each waiting
stream is registered in a list <opening_list> stored in qcc with <start>
as timestamp in qcs for the stream opening. Once a qcs is attached to a
sedesc, it is removed from <opening_list>. When refreshing MUX timeout,
if <opening_list> is not empty, the first waiting stream is used to set
MUX timeout.
This is efficient as streams are stored in the list in their creation
order so CPU usage is minimal. Also, the size of the list is
automatically restricted by flow control limitation so it should not
grow too much.
Streams are insert in <opening_list> by application protocol layer. This
is because only application protocol can differentiate streams for HTTP
messaging from internal usage. A function qcs_wait_http_req() has been
added to register a request stream by app layer. QUIC MUX can then
remove it from the list in qc_attach_sc().
As a side-note, it was necessary to implement attach qcc_app_ops
callback on hq-interop module to be able to insert a stream in waiting
list. Without this, a BUG_ON statement would be triggered when trying to
remove the stream on sedesc attach. This is to ensure that every
requests streams are registered for http-request timeout.
MUX timeout is explicitely refreshed on MAX_STREAM_DATA and STOP_SENDING
frame parsing to schedule http-request timeout if a new stream has been
instantiated. It was already done on STREAM parsing due to a previous
patch.
diff --git a/src/mux_quic.c b/src/mux_quic.c
index df6e304..e0d0746 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -130,6 +130,12 @@
qcs->st = QC_SS_IDLE;
qcs->ctx = NULL;
+ /* App callback attach may register the stream for http-request wait.
+ * These fields must be initialed before.
+ */
+ LIST_INIT(&qcs->el_opening);
+ qcs->start = TICK_ETERNITY;
+
/* Allocate transport layer stream descriptor. Only needed for TX. */
if (!quic_stream_is_uni(id) || !quic_stream_is_remote(qcc, id)) {
struct quic_conn *qc = qcc->conn->handle.qc;
@@ -302,18 +308,14 @@
* it with global close_spread delay applied.
*/
- /* TODO implement specific timeouts
- * - http-requset for waiting on incomplete streams
- * - client-fin for graceful shutdown
- */
+ /* TODO implement client/server-fin timeout for graceful shutdown */
/* Frontend timeout management
* - detached streams with data left to send -> default timeout
+ * - stream waiting on incomplete request or no stream yet activated -> timeout http-request
* - idle after stream processing -> timeout http-keep-alive
*/
if (!conn_is_back(qcc->conn)) {
- int timeout;
-
if (qcc->nb_hreq) {
TRACE_DEVEL("one or more requests still in progress", QMUX_EV_QCC_WAKE, qcc->conn);
qcc->task->expire = tick_add_ifset(now_ms, qcc->timeout);
@@ -321,12 +323,29 @@
goto leave;
}
- /* Use http-request timeout if keep-alive timeout not set */
- timeout = tick_isset(px->timeout.httpka) ?
- px->timeout.httpka : px->timeout.httpreq;
+ if (!LIST_ISEMPTY(&qcc->opening_list) || unlikely(!qcc->largest_bidi_r)) {
+ int timeout = px->timeout.httpreq;
+ struct qcs *qcs = NULL;
+ int base_time;
- TRACE_DEVEL("at least one request achieved but none currently in progress", QMUX_EV_QCC_WAKE, qcc->conn);
- qcc->task->expire = tick_add_ifset(qcc->idle_start, timeout);
+ /* Use start time of first stream waiting on HTTP or
+ * qcc idle if no stream not yet used.
+ */
+ if (likely(!LIST_ISEMPTY(&qcc->opening_list)))
+ qcs = LIST_ELEM(qcc->opening_list.n, struct qcs *, el_opening);
+ base_time = qcs ? qcs->start : qcc->idle_start;
+
+ TRACE_DEVEL("waiting on http request", QMUX_EV_QCC_WAKE, qcc->conn, qcs);
+ qcc->task->expire = tick_add_ifset(base_time, timeout);
+ }
+ else {
+ /* Use http-request timeout if keep-alive timeout not set */
+ int timeout = tick_isset(px->timeout.httpka) ?
+ px->timeout.httpka : px->timeout.httpreq;
+
+ TRACE_DEVEL("at least one request achieved but none currently in progress", QMUX_EV_QCC_WAKE, qcc->conn);
+ qcc->task->expire = tick_add_ifset(qcc->idle_start, timeout);
+ }
}
/* fallback to default timeout if frontend specific undefined or for
@@ -1015,6 +1034,9 @@
}
}
+ if (qcc_may_expire(qcc) && !qcc->nb_hreq)
+ qcc_refresh_timeout(qcc);
+
TRACE_LEAVE(QMUX_EV_QCC_RECV, qcc->conn);
return 0;
}
@@ -1064,6 +1086,9 @@
TRACE_DEVEL("receiving STOP_SENDING on stream", QMUX_EV_QCC_RECV|QMUX_EV_QCS_RECV, qcc->conn, qcs);
qcc_reset_stream(qcs, err);
+ if (qcc_may_expire(qcc) && !qcc->nb_hreq)
+ qcc_refresh_timeout(qcc);
+
out:
TRACE_LEAVE(QMUX_EV_QCC_RECV, qcc->conn);
return 0;
@@ -1931,6 +1956,7 @@
qcc->task->expire = tick_add(now_ms, qcc->timeout);
}
qcc_reset_idle_start(qcc);
+ LIST_INIT(&qcc->opening_list);
if (!conn_is_back(conn)) {
if (!LIST_INLIST(&conn->stopping_list)) {