CLEANUP: connection: use conn_ctrl_ready() instead of checking the flag

It's easier and safer to rely on conn_ctrl_ready() everywhere than to
check the flag itself. It will also simplify adding extra checks later
if needed. Some useless controls for !ctrl have been removed, as the
CTRL_READY flag itself guarantees ctrl is set.
diff --git a/src/checks.c b/src/checks.c
index 82aec1a..70b5a2e 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -800,7 +800,7 @@
 	if (conn->flags & CO_FL_ERROR && ((errno && errno != EAGAIN) || !conn->ctrl))
 		return 1;
 
-	if (!(conn->flags & CO_FL_CTRL_READY) || !conn->ctrl)
+	if (!conn_ctrl_ready(conn))
 		return 0;
 
 	if (getsockopt(conn->t.sock.fd, SOL_SOCKET, SO_ERROR, &skerr, &lskerr) == 0)
diff --git a/src/connection.c b/src/connection.c
index f85e775..1483f18 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -157,7 +157,7 @@
 {
 	unsigned int f = c->flags;
 
-	if (!(c->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(c))
 		return;
 
 	/* update read status if needed */
@@ -192,7 +192,7 @@
 {
 	unsigned int f = c->flags;
 
-	if (!(c->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(c))
 		return;
 
 	/* update read status if needed */
@@ -248,7 +248,7 @@
 	if (conn->flags & CO_FL_SOCK_RD_SH)
 		goto fail;
 
-	if (!(conn->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(conn))
 		goto fail;
 
 	if (!fd_recv_ready(conn->t.sock.fd))
diff --git a/src/dumpstats.c b/src/dumpstats.c
index 19d4dbd..18aadf6 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -4286,7 +4286,7 @@
 
 static inline const char *get_conn_ctrl_name(const struct connection *conn)
 {
-	if (!(conn->flags & CO_FL_CTRL_READY) || !conn->ctrl)
+	if (!conn_ctrl_ready(conn))
 		return "NONE";
 	return conn->ctrl->name;
 }
diff --git a/src/proto_http.c b/src/proto_http.c
index bc5b014..95fb870 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -2502,7 +2502,7 @@
 		req->flags |= CF_READ_DONTWAIT; /* try to get back here ASAP */
 		s->rep->flags &= ~CF_EXPECT_MORE; /* speed up sending a previous response */
 #ifdef TCP_QUICKACK
-		if (s->listener->options & LI_O_NOQUICKACK && req->buf->i && objt_conn(s->req->prod->end) && (__objt_conn(s->req->prod->end)->flags & CO_FL_CTRL_READY)) {
+		if (s->listener->options & LI_O_NOQUICKACK && req->buf->i && objt_conn(s->req->prod->end) && conn_ctrl_ready(__objt_conn(s->req->prod->end))) {
 			/* We need more data, we have to re-enable quick-ack in case we
 			 * previously disabled it, otherwise we might cause the client
 			 * to delay next data.
@@ -3031,13 +3031,13 @@
 			break;
 
 		case HTTP_REQ_ACT_SET_TOS:
-			if ((cli_conn = objt_conn(s->req->prod->end)) && (cli_conn->flags & CO_FL_CTRL_READY))
+			if ((cli_conn = objt_conn(s->req->prod->end)) && conn_ctrl_ready(cli_conn))
 				inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, rule->arg.tos);
 			break;
 
 		case HTTP_REQ_ACT_SET_MARK:
 #ifdef SO_MARK
-			if ((cli_conn = objt_conn(s->req->prod->end)) && (cli_conn->flags & CO_FL_CTRL_READY))
+			if ((cli_conn = objt_conn(s->req->prod->end)) && conn_ctrl_ready(cli_conn))
 				setsockopt(cli_conn->t.sock.fd, SOL_SOCKET, SO_MARK, &rule->arg.mark, sizeof(rule->arg.mark));
 #endif
 			break;
@@ -3117,13 +3117,13 @@
 			break;
 
 		case HTTP_RES_ACT_SET_TOS:
-			if ((cli_conn = objt_conn(s->req->prod->end)) && (cli_conn->flags & CO_FL_CTRL_READY))
+			if ((cli_conn = objt_conn(s->req->prod->end)) && conn_ctrl_ready(cli_conn))
 				inet_set_tos(cli_conn->t.sock.fd, cli_conn->addr.from, rule->arg.tos);
 			break;
 
 		case HTTP_RES_ACT_SET_MARK:
 #ifdef SO_MARK
-			if ((cli_conn = objt_conn(s->req->prod->end)) && (cli_conn->flags & CO_FL_CTRL_READY))
+			if ((cli_conn = objt_conn(s->req->prod->end)) && conn_ctrl_ready(cli_conn))
 				setsockopt(cli_conn->t.sock.fd, SOL_SOCKET, SO_MARK, &rule->arg.mark, sizeof(rule->arg.mark));
 #endif
 			break;
@@ -4004,7 +4004,7 @@
 		 * the client to delay further data.
 		 */
 		if ((s->listener->options & LI_O_NOQUICKACK) &&
-		    cli_conn && (cli_conn->flags & CO_FL_CTRL_READY) &&
+		    cli_conn && conn_ctrl_ready(cli_conn) &&
 		    ((msg->flags & HTTP_MSGF_TE_CHNK) ||
 		     (msg->body_len > req->buf->i - txn->req.eoh - 2)))
 			setsockopt(cli_conn->t.sock.fd, IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one));
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 79c7baf..cd05678 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -626,7 +626,7 @@
 	if (conn->flags & CO_FL_ERROR)
 		return 0;
 
-	if (!(conn->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(conn))
 		return 0;
 
 	if (!(conn->flags & CO_FL_WAIT_L4_CONN))
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index d30a8eb..31f0939 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -1097,7 +1097,7 @@
 	if (conn->xprt_ctx)
 		return 0;
 
-	if (!(conn->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(conn))
 		return 0;
 
 	if (global.maxsslconn && sslconns >= global.maxsslconn) {
@@ -1169,7 +1169,7 @@
 {
 	int ret;
 
-	if (!(conn->flags & CO_FL_CTRL_READY))
+	if (!conn_ctrl_ready(conn))
 		return 0;
 
 	if (!conn->xprt_ctx)