MEDIUM: mux-quic: support backend private connection

If a backend connection is private, it should not be reused outside of
its original attached session. As such, on stream detach operation, such
connection is never inserted into server idle/avail list. Instead, it is
stored directly on the session.

The purpose of this commit is to implement proper handling of private
backend connections via QUIC multiplexer.

diff --git a/src/mux_quic.c b/src/mux_quic.c
index 87d981154dada42b4fe2e6f06857b3c8cfdfe98b..1a0db225c360ec23bc6c653f525df6cac32fe51e 100644 (file)
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -3751,6 +3751,7 @@ static void qmux_strm_detach(struct sedesc *sd)
        struct qcs *qcs = sd->se;
        struct qcc *qcc = qcs->qcc;
        struct connection *conn = qcc->conn;
+       struct session *sess = qcs->sess;
 
        TRACE_ENTER(QMUX_EV_STRM_END, conn, qcs);
 
@@ -3780,7 +3781,32 @@ static void qmux_strm_detach(struct sedesc *sd)
        /* Backend connection can be reused unless it is already on error/closed. */
        if ((qcc->flags & QC_CF_IS_BACK) && !qcc_is_dead(qcc) &&
            qcc->app_st == QCC_APP_ST_INIT) {
-               if (!(conn->flags & CO_FL_PRIVATE)) {
+               if (conn->flags & CO_FL_PRIVATE) {
+                       TRACE_DEVEL("handle private connection reuse", QMUX_EV_STRM_END, conn);
+
+                       /* Add connection into session. If an error occured,
+                        * conn will be closed if idle, or insert will be
+                        * retried on next detach.
+                        */
+                       if (!session_add_conn(sess, conn, conn->target)) {
+                               TRACE_ERROR("error during connection insert into session list", QMUX_EV_STRM_END, conn);
+                               conn->owner = NULL;
+                               if (!qcc->nb_sc) {
+                                       qcc_shutdown(qcc);
+                                       goto end;
+                               }
+                       }
+
+                       /* If conn is idle, check if session can keep it. Conn is freed if this is not the case.
+                        * TODO graceful shutdown should be preferable instead of plain mux->destroy().
+                        */
+                       if (!qcc->nb_sc && session_check_idle_conn(sess, conn)) {
+                               TRACE_DEVEL("idle conn rejected by session", QMUX_EV_STRM_END);
+                               conn = NULL;
+                               goto end;
+                       }
+               }
+               else {
                        if (!qcc->nb_sc) {
                                TRACE_DEVEL("prepare for idle connection reuse", QMUX_EV_STRM_END, conn);
                                if (!srv_add_to_idle_list(objt_server(conn->target), conn, 1)) {