BUG/MINOR: mux_quic: refresh timeout only if I/O performed

Previously, QUIC MUX timeout was refreshed on every qcc_io_cb()
execution. This is not desired if no send/receive were performed, as in
this case the connection may be stuck.

This patch fixes this by refreshing timeout only if some progress is
performed during qcc_io_cb(). To implement this, return value of
qcc_io_recv() has been adjusted to return the number of newly decoded
bytes.

This patch is considered as a bug fix as without it there is a risk of
QUIC MUX inactivity timeout to be less efficient and to maintain a
connection too long.

This should be backported up to 2.8, after a period of observation.

diff --git a/src/mux_quic.c b/src/mux_quic.c
index ff2f9523dc41839047c592971151bf77eca7c75c..7a1500db8e449d31b2c678f990594c84e8207673 100644 (file)
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -3247,12 +3247,12 @@ static void qcc_wait_for_hs(struct qcc *qcc)
 /* Proceed on receiving. Loop on streams subscribed in recv_list and performed
  * STREAM frames decoding upon them.
  *
- * Returns 0 on success else non-zero.
+ * Returns the number of newly transcoded bytes.
  */
 static int qcc_io_recv(struct qcc *qcc)
 {
        struct qcs *qcs;
-       int ret;
+       int total = 0, ret;
 
        TRACE_ENTER(QMUX_EV_QCC_RECV, qcc->conn);
 
@@ -3281,12 +3281,13 @@ static int qcc_io_recv(struct qcc *qcc)
 
                        if (ret <= 0)
                                goto done;
+                       total += ret;
                }
        }
 
  done:
        TRACE_LEAVE(QMUX_EV_QCC_RECV, qcc->conn);
-       return 0;
+       return total;
 }
 
 /* Calculate the number of bidirectional streams which can still be opened for
@@ -3613,7 +3614,7 @@ struct task *qcc_io_cb(struct task *t, void *ctx, unsigned int state)
 {
        struct qcc *qcc = ctx;
        struct connection *conn;
-       int conn_in_list;
+       int total = 0, conn_in_list;
 
        if (state & TASK_F_USR1) {
                /* the tasklet was idling on an idle connection, it might have
@@ -3661,16 +3662,17 @@ struct task *qcc_io_cb(struct task *t, void *ctx, unsigned int state)
        }
 
        if (!(qcc->wait_event.events & SUB_RETRY_SEND))
-               qcc_io_send(qcc);
+               total += qcc_io_send(qcc);
 
-       qcc_io_recv(qcc);
+       total += qcc_io_recv(qcc);
 
        if (qcc_io_process(qcc)) {
                TRACE_STATE("releasing dead connection", QMUX_EV_QCC_WAKE, conn);
                goto release;
        }
 
-       qcc_refresh_timeout(qcc);
+       if (total)
+               qcc_refresh_timeout(qcc);
 
        /* Trigger pacing task is emission should be retried after some delay. */
        if (qcc_is_pacing_active(conn)) {