MINOR: quic: remove unnecessary quic_session_accept()

A specialized listener accept was previously used for QUIC. This is now
unneeded and we can revert to the default one session_accept_fd().

One change of importance is that the call order between
conn_xprt_start() and conn_complete_session() is now reverted to the
default one. This means that MUX instance is now NULL during
qc_xprt_start() and its app-ops layer cannot be set here. This operation
has been delayed to qc_init() to prevent a segfault.

This should be backported up to 2.6.

src/cfgparse.c

@@ -4326,7 +4326,7 @@ init_proxies_list_stage2:
 			if (listener->flags & LI_F_QUIC_LISTENER) {
 				if (!global.cluster_secret)
 					diag_no_cluster_secret = 1;
-				listener->accept = quic_session_accept;
+
 				li_init_per_thr(listener);
 			}
 #endif

src/mux_quic.c

@@ -1915,6 +1915,12 @@ static int qc_init(struct connection *conn, struct proxy *prx,
 	qcc->flags = 0;
 
 	qcc->app_ops = NULL;
+	if (qcc_install_app_ops(qcc, conn->handle.qc->app_ops)) {
+		TRACE_PROTO("Cannot install app layer", QMUX_EV_QCC_NEW, qcc->conn);
+		/* prepare a CONNECTION_CLOSE frame */
+		quic_set_connection_close(conn->handle.qc, quic_err_transport(QC_ERR_APPLICATION_ERROR));
+		goto fail_no_tasklet;
+	}
 
 	qcc->streams_by_id = EB_ROOT_UNIQUE;
 
@@ -2024,6 +2030,8 @@ static int qc_init(struct connection *conn, struct proxy *prx,
  fail_no_timeout_task:
 	tasklet_free(qcc->wait_event.tasklet);
  fail_no_tasklet:
+	if (qcc->app_ops && qcc->app_ops->release)
+		qcc->app_ops->release(qcc->ctx);
 	pool_free(pool_head_qcc, qcc);
  fail_no_qcc:
 	TRACE_LEAVE(QMUX_EV_QCC_NEW);

src/quic_sock.c

@@ -38,76 +38,6 @@
 #include <haproxy/task.h>
 #include <haproxy/tools.h>
 
-/* This function is called from the protocol layer accept() in order to
- * instantiate a new session on behalf of a given listener and frontend. It
- * returns a positive value upon success, 0 if the connection can be ignored,
- * or a negative value upon critical failure. The accepted connection is
- * closed if we return <= 0. If no handshake is needed, it immediately tries
- * to instantiate a new stream. The connection must already have been filled
- * with the incoming connection handle (a fd), a target (the listener) and a
- * source address.
- */
-int quic_session_accept(struct connection *cli_conn)
-{
-	struct listener *l = __objt_listener(cli_conn->target);
-	struct proxy *p = l->bind_conf->frontend;
-	struct session *sess;
-
-	cli_conn->proxy_netns = l->rx.settings->netns;
-	/* This flag is ordinarily set by conn_ctrl_init() which cannot
-	 * be called for now.
-	 */
-	cli_conn->flags |= CO_FL_CTRL_READY;
-
-	/* wait for a PROXY protocol header */
-	if (l->options & LI_O_ACC_PROXY)
-		cli_conn->flags |= CO_FL_ACCEPT_PROXY;
-
-	/* wait for a NetScaler client IP insertion protocol header */
-	if (l->options & LI_O_ACC_CIP)
-		cli_conn->flags |= CO_FL_ACCEPT_CIP;
-
-	/* Add the handshake pseudo-XPRT */
-	if (cli_conn->flags & (CO_FL_ACCEPT_PROXY | CO_FL_ACCEPT_CIP)) {
-		if (xprt_add_hs(cli_conn) != 0)
-			goto out_free_conn;
-	}
-
-	sess = session_new(p, l, &cli_conn->obj_type);
-	if (!sess)
-		goto out_free_conn;
-
-	conn_set_owner(cli_conn, sess, NULL);
-
-	if (conn_complete_session(cli_conn) < 0)
-		goto out_free_sess;
-
-	if (conn_xprt_start(cli_conn) < 0) {
-		/* conn_complete_session has succeeded : conn is the owner of
-		 * the session and the MUX is initialized.
-		 * Let the MUX free all resources on error.
-		 */
-		cli_conn->mux->destroy(cli_conn->ctx);
-		return -1;
-	}
-
-	return 1;
-
- out_free_sess:
-	/* prevent call to listener_release during session_free. It will be
-	* done below, for all errors. */
-	sess->listener = NULL;
-	session_free(sess);
- out_free_conn:
-	cli_conn->handle.qc->conn = NULL;
-	conn_stop_tracking(cli_conn);
-	conn_xprt_close(cli_conn);
-	conn_free(cli_conn);
- out:
-
-	return -1;
-}
-
 /* Retrieve a connection's source address. Returns -1 on failure. */
 int quic_sock_get_src(struct connection *conn, struct sockaddr *addr, socklen_t len)
 {
@@ -182,12 +112,6 @@ static int new_quic_cli_conn(struct quic_conn *qc, struct listener *l,
 
 	cli_conn->target = &l->obj_type;
 
-	/* We need the xprt context before accepting (->accept()) the connection:
-	 * we may receive packet before this connection acception.
-	 */
-	if (conn_prepare(cli_conn, l->rx.proto, l->bind_conf->xprt) < 0)
-		goto out_free_conn;
-
 	return 1;
 
  out_free_conn:

src/xprt_quic.c

@@ -121,12 +121,6 @@ static int qc_xprt_start(struct connection *conn, void *ctx)
 
 	qc = conn->handle.qc;
 	TRACE_ENTER(QUIC_EV_CONN_NEW, qc);
-	if (qcc_install_app_ops(qc->qcc, qc->app_ops)) {
-		TRACE_PROTO("Cannot install app layer", QUIC_EV_CONN_LPKT, qc);
-		/* prepare a CONNECTION_CLOSE frame */
-		quic_set_connection_close(qc, quic_err_transport(QC_ERR_APPLICATION_ERROR));
-		goto out;
-	}
 
 	/* mux-quic can now be considered ready. */
 	qc->mux_state = QC_MUX_READY;