From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Wed, 29 Apr 2026 13:10:13 +0000 (+0200)
Subject: MINOR: backend: support QMux in clear for BE side
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6717531053bd69a206f52ff24ec5e2f66371d774;p=thirdparty%2Fhaproxy.git

MINOR: backend: support QMux in clear for BE side

Use xprt_add_l6hs() at the end of connect_server() if selected MUX layer
relies on a temporary handshake prior to its initialization. This
functions is noop is SSL layer is active.

This change is necessary to support clear QMux on the backend side.
Recently defined <init_xprt> from mux_proto_list is used to render the
code as generic as possible.
---

diff --git a/src/backend.c b/src/backend.c
index 45bdb3899..726c88d60 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1818,7 +1818,7 @@ int connect_server(struct stream *s)
 {
 	struct connection *cli_conn = objt_conn(strm_orig(s));
 	struct connection *srv_conn = NULL;
-	const struct mux_proto_list *mux_proto;
+	const struct mux_proto_list *mux_proto = NULL;
 	struct server *srv;
 	struct ist name = IST_NULL;
 	struct sample *name_smp;
@@ -2139,12 +2139,10 @@ int connect_server(struct stream *s)
 		}
 
 		if (may_start_mux_now) {
-			/* Delay QMux MUX init to let xprt_qmux handshake runs first. */
+			/* Delay MUX init if an XPRT handshake is required prior. */
 			mux_proto = conn_select_mux_be(srv_conn);
-			if (mux_proto && mux_proto->init_xprt == XPRT_QMUX) {
-				srv_conn->flags |= (CO_FL_QMUX_RECV|CO_FL_QMUX_SEND);
+			if (mux_proto && mux_proto->init_xprt)
 				may_start_mux_now = 0;
-			}
 		}
 
 #if defined(USE_OPENSSL) && defined(TLSEXT_TYPE_application_layer_protocol_negotiation)
@@ -2254,6 +2252,13 @@ int connect_server(struct stream *s)
 			}
 		}
 	}
+	else if (mux_proto && mux_proto->init_xprt) {
+		/* Add handshake layer prior to MUX init if required. Does nothing if SSL layer is active though. */
+		if (xprt_add_l6hs(srv_conn, mux_proto->init_xprt)) {
+			conn_full_close(srv_conn);
+			return SF_ERR_INTERNAL;
+		}
+	}
 
 	/*
 	 * Now that the mux may have been created, we can start the xprt.