libctrl: Change controlif_setup so it returns the ctrl handle

nat: Catch up with controlif_setup API change
We now save a control handle reference in the nat
osmo-bsc: Catch up with controlif_setup API change
We now save a control handle reference in the gsm network
diff --git a/openbsc/src/libctrl/control_if.c b/openbsc/src/libctrl/control_if.c
index 36fdc28..e871a51 100644
--- a/openbsc/src/libctrl/control_if.c
+++ b/openbsc/src/libctrl/control_if.c
@@ -39,6 +39,7 @@
 #include <sys/types.h>
 
 #include <openbsc/control_cmd.h>
+#include <openbsc/control_if.h>
 #include <openbsc/debug.h>
 #include <openbsc/gsm_data.h>
 #include <openbsc/ipaccess.h>
@@ -62,14 +63,6 @@
 #include <osmocom/abis/e1_input.h>
 #include <osmocom/abis/ipa.h>
 
-struct ctrl_handle {
-	struct osmo_fd listen_fd;
-	struct gsm_network *gsmnet;
-
-	/* List of control connections */
-	struct llist_head ccon_list;
-};
-
 vector ctrl_node_vec;
 
 int ctrl_cmd_send(struct osmo_wqueue *queue, struct ctrl_cmd *cmd)
@@ -607,33 +600,37 @@
 	return 0;
 }
 
-int controlif_setup(struct gsm_network *gsmnet, uint16_t port)
+struct ctrl_handle *controlif_setup(struct gsm_network *gsmnet, uint16_t port)
 {
 	int ret;
 	struct ctrl_handle *ctrl;
 
 	ctrl = talloc_zero(tall_bsc_ctx, struct ctrl_handle);
 	if (!ctrl)
-		return -ENOMEM;
+		return NULL;
 
 	INIT_LLIST_HEAD(&ctrl->ccon_list);
 
 	ctrl->gsmnet = gsmnet;
 
 	ctrl_node_vec = vector_init(5);
-	if (!ctrl_node_vec)
-		return -ENOMEM;
+	if (!ctrl_node_vec) {
+		talloc_free(ctrl);
+		return NULL;
+	}
 
 	/* Listen for control connections */
 	ret = make_sock(&ctrl->listen_fd, IPPROTO_TCP, INADDR_LOOPBACK, port,
 			0, listen_fd_cb, ctrl);
 	if (ret < 0) {
 		talloc_free(ctrl);
-		return ret;
+		vector_free(ctrl_node_vec);
+		ctrl_node_vec = NULL;
+		return NULL;
 	}
 
 	ctrl_cmd_install(CTRL_NODE_ROOT, &cmd_rate_ctr);
 	ctrl_cmd_install(CTRL_NODE_ROOT, &cmd_counter);
 
-	return ret;
+	return ctrl;
 }