MEDIUM: mux: Add an optional "reset" method.

Add a new method to mux, "reset", that is used to let the mux know the
connection attempt failed, and we're about to retry, so it just have to
reinit itself. Currently only the H1 mux needs it.

include/types/connection.h

@@ -337,6 +337,7 @@ struct mux_ops {
 	int (*avail_streams)(struct connection *conn); /* Returns the number of streams still available for a connection */
 	int (*max_streams)(struct connection *conn);   /* Returns the max number of streams available for that connection. */
 	void (*destroy)(struct connection *conn); /* Let the mux know one of its users left, so it may have to disappear */
+	void (*reset)(struct connection *conn); /* Reset the mux, because we're re-trying to connect */
 	const struct cs_info *(*get_cs_info)(struct conn_stream *cs); /* Return info on the specified conn_stream or NULL if not defined */
 	unsigned int flags;                           /* some flags characterizing the mux's capabilities (MX_FL_*) */
 	char name[8];                                 /* mux layer name, zero-terminated */

src/backend.c

@@ -1293,7 +1293,7 @@ int connect_server(struct stream *s)
 			return SF_ERR_INTERNAL;
 	}
 
-	if (!conn_xprt_ready(srv_conn)) {
+	if (!conn_xprt_ready(srv_conn) && !srv_conn->mux) {
 		/* the target was only on the stream, assign it to the SI now */
 		srv_conn->target = s->target;
 
@@ -1361,6 +1361,10 @@ int connect_server(struct stream *s)
 
 		assign_tproxy_address(s);
 	}
+	else if (!conn_xprt_ready(srv_conn)) {
+		if (srv_conn->mux->reset)
+			srv_conn->mux->reset(srv_conn);
+	}
 	else
 		s->flags |= SF_SRV_REUSED;
 

src/mux_h1.c

@@ -1824,6 +1824,13 @@ static struct task *h1_io_cb(struct task *t, void *ctx, unsigned short status)
 	return NULL;
 }
 
+static void h1_reset(struct connection *conn)
+{
+	struct h1c *h1c = conn->mux_ctx;
+
+	/* Reset the flags, and let the mux know we're waiting for a connection */
+	h1c->flags = H1C_F_CS_WAIT_CONN;
+}
 
 static int h1_wake(struct connection *conn)
 {
@@ -2171,6 +2178,7 @@ const struct mux_ops mux_h1_ops = {
 	.unsubscribe = h1_unsubscribe,
 	.shutr       = h1_shutr,
 	.shutw       = h1_shutw,
+	.reset       = h1_reset,
 	.flags       = MX_FL_NONE,
 	.name        = "h1",
 };