MINOR: mux: Add a new method to get informations about a mux.

Add a new method, ctl(), to muxes. It uses a "enum mux_ctl_type" to
let it know which information we're asking for, and can output it either
directly by returning the expected value, or by using an optional argument.
"output" argument.
Right now, the only known mux_ctl_type is MUX_STATUS, that will return 0 if
the mux is not ready, or MUX_STATUS_READY if the mux is ready.

We probably want to backport this to 1.9 and 2.0.

include/types/connection.h

@@ -331,6 +331,12 @@ struct xprt_ops {
 	int (*add_xprt)(struct connection *conn, void *xprt_ctx, void *toadd_ctx, const struct xprt_ops *toadd_ops, void **oldxprt_ctx, const struct xprt_ops **oldxprt_ops); /* Add a new XPRT as the new xprt, and return the old one */
 };
 
+enum mux_ctl_type {
+	MUX_STATUS, /* Expects an int as output, sets it to a combinaison of MUX_STATUS flags */
+};
+
+#define MUX_STATUS_READY (1 << 0)
+
 /* mux_ops describes the mux operations, which are to be performed at the
  * connection level after data are exchanged with the transport layer in order
  * to propagate them to streams. The <init> function will automatically be
@@ -359,6 +365,7 @@ struct mux_ops {
 	void (*destroy)(void *ctx); /* 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 */
+	int (*ctl)(struct connection *conn, enum mux_ctl_type mux_ctl, void *arg); /* Provides informations about the mux */
 	unsigned int flags;                           /* some flags characterizing the mux's capabilities (MX_FL_*) */
 	char name[8];                                 /* mux layer name, zero-terminated */
 };

src/mux_fcgi.c

@@ -3000,6 +3000,20 @@ static int fcgi_wake(struct connection *conn)
 	return (fcgi_process(fconn));
 }
 
+
+static int fcgi_ctl(struct connection *conn, enum mux_ctl_type mux_ctl, void *output)
+{
+	int ret = 0;
+	switch (mux_ctl) {
+	case MUX_STATUS:
+		if (conn->flags & CO_FL_CONNECTED)
+			ret |= MUX_STATUS_READY;
+		return ret;
+	default:
+		return -1;
+	}
+}
+
 /* Connection timeout management. The principle is that if there's no receipt
  * nor sending for a certain amount of time, the connection is closed. If the
  * MUX buffer still has lying data or is not allocatable, the connection is
@@ -4050,6 +4064,7 @@ static const struct mux_ops mux_fcgi_ops = {
 	.unsubscribe   = fcgi_unsubscribe,
 	.shutr         = fcgi_shutr,
 	.shutw         = fcgi_shutw,
+	.ctl           = fcgi_ctl,
 	.show_fd       = fcgi_show_fd,
 	.flags         = MX_FL_HTX,
 	.name          = "FCGI",

src/mux_h1.c

@@ -2727,6 +2727,19 @@ static int h1_snd_pipe(struct conn_stream *cs, struct pipe *pipe)
 }
 #endif
 
+static int h1_ctl(struct connection *conn, enum mux_ctl_type mux_ctl, void *output)
+{
+	int ret = 0;
+	switch (mux_ctl) {
+	case MUX_STATUS:
+		if (conn->flags & CO_FL_CONNECTED)
+			ret |= MUX_STATUS_READY;
+		return ret;
+	default:
+		return -1;
+	}
+}
+
 /* for debugging with CLI's "show fd" command */
 static void h1_show_fd(struct buffer *msg, struct connection *conn)
 {
@@ -2974,6 +2987,7 @@ static const struct mux_ops mux_h1_ops = {
 	.shutw       = h1_shutw,
 	.show_fd     = h1_show_fd,
 	.reset       = h1_reset,
+	.ctl         = h1_ctl,
 	.flags       = MX_FL_HTX,
 	.name        = "H1",
 };

src/mux_h2.c

@@ -3792,6 +3792,24 @@ static const struct conn_stream *h2_get_first_cs(const struct connection *conn)
 	return NULL;
 }
 
+static int h2_ctl(struct connection *conn, enum mux_ctl_type mux_ctl, void *output)
+{
+	int ret = 0;
+	struct h2c *h2c = conn->ctx;
+
+	switch (mux_ctl) {
+	case MUX_STATUS:
+		/* Only consider the mux to be ready if we're done with
+		 * the preface and settings, and we had no error.
+		 */
+		if (h2c->st0 >= H2_CS_FRAME_H && h2c->st0 < H2_CS_ERROR)
+			ret |= MUX_STATUS_READY;
+		return ret;
+	default:
+		return -1;
+	}
+}
+
 /*
  * Destroy the mux and the associated connection, if it is no longer used
  */
@@ -6095,6 +6113,7 @@ static const struct mux_ops h2_ops = {
 	.used_streams = h2_used_streams,
 	.shutr = h2_shutr,
 	.shutw = h2_shutw,
+	.ctl = h2_ctl,
 	.show_fd = h2_show_fd,
 	.flags = MX_FL_CLEAN_ABRT|MX_FL_HTX,
 	.name = "H2",

src/mux_pt.c

@@ -333,6 +333,19 @@ static int mux_pt_snd_pipe(struct conn_stream *cs, struct pipe *pipe)
 }
 #endif
 
+static int mux_pt_ctl(struct connection *conn, enum mux_ctl_type mux_ctl, void *output)
+{
+	int ret = 0;
+	switch (mux_ctl) {
+	case MUX_STATUS:
+		if (conn->flags & CO_FL_CONNECTED)
+			ret |= MUX_STATUS_READY;
+		return ret;
+	default:
+		return -1;
+	}
+}
+
 /* The mux operations */
 const struct mux_ops mux_pt_ops = {
 	.init = mux_pt_init,
@@ -351,6 +364,7 @@ const struct mux_ops mux_pt_ops = {
 	.avail_streams = mux_pt_avail_streams,
 	.used_streams = mux_pt_used_streams,
 	.destroy = mux_pt_destroy_meth,
+	.ctl = mux_pt_ctl,
 	.shutr = mux_pt_shutr,
 	.shutw = mux_pt_shutw,
 	.flags = MX_FL_NONE,